Discussion Question Essay

1. Briefly describe Moore law. What are the implications of this law? Are there any practical limitations to Moore law? Moore’s Law is a hypothesis stating that transistor densities on a single chip double every two years. Moore’s law describes a long-term trend in the history of computing hardware. The number of transistors that can be placed inexpensively on an integrated circuit has doubled approximately every two years. Moore’s law is a rule of thumb in the computer industry about the growth of computing power over time. Attributed to Gordon E. Moore the co-founder of Intel, it states that the growth of computing power follows an empirical exponential law. Moore originally proposed a 12 month doubling and, later, a 24 month period. Due to the mathematical nature of doubling, this implies that within 30-50 years computers will become more intelligent than human beings. The implications of many digital electronic devices are strongly linked to Moore’s law: processing speed, memory capacity, sensors and even the number and size of pixels in digital cameras.All of these are improving at (roughly) exponential rates as well. This has dramatically increased the usefulness of digital electronics in nearly every segment of the world economy. Moore’s law precisely describes a driving force of technological and social change in the late 20th and early 21st centuries. Transistors per integrated circuit. The most popular formulation is of the doubling of the number of transistors on integrated circuits every two years. At the end of the 1970s, Moore’s law became known as the limit for the number of transistors on the most complex chips. Recent trends show that this rate has been maintained into 2007. Density at minimum cost per transistor. This is the formulation given in Moore’s 1965 paper. It is not just about the density of transistors that can be achieved, but about the density of transistors at which the cost per transistor is the lowest. As more transistors are  put on a chip, the cost to make each transistor decreases, but the chance that the chip will not work due to a defect increases. In 1965, Moore examined the density of transistors at which cost is minimized, and observed that, as transistors were made smaller through advances in photolithography, this number would increase at â€Å"a rate of roughly a factor of two pe r year†. Power consumption. The power consumption of computer nodes doubles every 18 months.Hard disk storage cost per unit of information. A similar law (sometimes called Kryder’s Law) has held for hard disk storage cost per unit of information. The rate of progression in disk storage over the past decades has actually sped up more than once, corresponding to the utilization of error correcting codes, the magnetoresistive effect and the giant magnetoresistive effect. The current rate of increase in hard drive capacity is roughly similar to the rate of increase in transistor count. Recent trends show that this rate has been maintained into 2007.Network capacity. According to Gerry/Gerald Butters, the former head of Lucent’s Optical Networking Group at Bell Labs, there is another version, called Butter’s Law of Photonics, a formulation which deliberately parallels Moore’s law. Butter’s law says that the amount of data coming out of an optical fiber is doubling every nine months. Thus, the cost of transmitting a bit over an optical network decreases by half every nine months. The availability of wavelength-division multiplexing (sometimes called â€Å"WDM†) increased the capacity that could be placed on a single fiber by as much as a factor of 100. Optical networking and dense wavelength-division multiplexing (DWDM) is rapidly bringing down the cost of networking, and further progress seems assured. As a result, the wholesale price of data traffic collapsed in the dot-com bubble. Nielsen’s Law says that the bandwidth available to users increases by 50% annually. 2. What is a quad core processor? What advantages does it offer users? Quad-core processors are computer central processing units (CPUs) that have four separate processing cores contained in a single device. Intel and AMD, two popular CPU manufacturers, both produce quad-core processors. Quad-core processors carry several advantages over normal single-core processors, though there is skepticism as to how much of an advantage they are for the average computer user. Multitasking. Perhaps the most significant benefit of quad-core processors is their ability to handle several applications at the same time. When you run a few different programs on a single-core processor, it slows down from running data calculations for many programs at once. With a quad-core processor, each core is responsible for a different process, so even running four demanding programs can be possible without experiencing much delay from a lack of processing power. Future Programs. One of the frequently cited benefits of quad-core processors is that they are â€Å"future proof.† As of summer 2009, there are not many programs that can utilize the full power of a quad-core processor, but programs and games capable of using multiple cores in parallel will be developed in the future. If and when this happens, computers without multiple cores will quickly become obsolete while those with quadcore processors will likely remain useful until developers make programs that can utilize an even greater number of processors. Taxing Processes. Another area in which quad-core processors will yield significant benefits is in processes that require calculations on large amounts of data, such as rendering 3D graphics, compressing CDs or DVDs and audio and video editing. Enterprise resource planning and customer relationship management applications also see a noticeable benefit with quad-core processors. Power Consumption. The integrated architecture of a quad-core processor uses less power than if the four cores were split into separate physical units. This is important, since the  amount of electricity required by computer power supplies has risen quickly in recent years. Also, newer CPUs are beginning to use 45nm architecture, which requires less power and produce less heat than the larger 60nm processor architecture. Criticism. Until programs take full advantage of multiple cores, there will not be a significant difference in performance between quad-core and dual-core processors, and perhaps even quad-core and single-core processors. Considering the rapid progress of computer technology, there may be processors with eight, ten or more cores by the time programs are developed that properly utilize parallel processing of many cores. 3. What would be an advantage for a university computer lab to install thin clients rather than standard desktop personal computer? Can you identify any disadvantages? A thin client is an aesthetically slim PC used as an access point for server-based computing. It has fewer parts and requires fewer components to run; hence, it has numerous cost efficiency benefits. Although thin client benefits are remarkable, we must also look into their disadvantages. Thin client computing fits a lot of work environments. Since thin clients do not need to be in the same place as their server, the setup presents thin client benefits that are mostly practical. Clients can be taken into the harshest of work places like dusty desert camps and can be deployed even after the occurrence of a natural disaster. Thin clients are also perfect for environments where space is a big issue. A thin client has an inherent space-conserving attribute since they come in one piece with only the monitor showing while the unit is hidden behind it. Some even mount on walls with only the peripherals and the monitor exposed. Even work places with very little budget room to run air conditioning systems can be expected to gain with thin client benefits in their facilities. The absence of dynamic or moving parts to serve one’s computing purpose entails less generation of heat. This is mainly because thin clients make use of solid state devices like flash drives instead of hard drives. However, as ideal as a server based computing may all seem, there are notable disadvantages which concern costs and performance abilities. Below is a rundown of advantages and disadvantages you should consider before deciding to use thin client computing in your university computer lab. Advantages of Thin Computing: Lower Operational Costs- An office environment where several workstations are involved will access a single server unit, thereby reducing the operational costs covering these related actions: * Setting up the device takes less than ten minutes to accomplish. * The lifespan of thin clients is very long since there are no moving parts inside each unit. The only parts that need constant replacements are the peripherals which are external to the unit. This brings cost efficiency in the maintenance aspect which means when something breaks on the client’s end, it can be as easy as taking a replacement unit to replace the broken one. Even wear and tear is considerably unnoticeable. * Energy efficiency- A thin client unit is said to consume 20W to 40W as opposed to the regular thick PC where power consumption during operation mode consumes 60W to 110W. In addition, thin clients themselves need little to no air conditioning at all, which literally means less operating costs. Whatever air conditioning needed is demanded and supplied at the server area. * Work efficiency- The thin client work environment can be far reaching and extensive; it can provide quick access to remotely located workers, also operating on server-based computing. Superior Security – Since users will only have access to the server by network connections, security measures like different access levels for different users can be implemented. This way, users with lower access levels will not be able to see, know, or in worst case scenarios, hack into the confidential files and applications of the entire organization since they are all secured at the server’s end. It is also a way of securing the data in the event of natural disasters. The servers will be the only machines that need to survive the disaster as the server is the main location of all the saved data. Immediately after the disaster, new clients can easily be connected to the server as long as the server is intact. Lower Malware Infection Risks – There is a very slim chance of getting malware on the server from a thin client. The client inputs to the server will only be coming from the keyboard, mouse actions, and screen images. Thin clients get their software or programs from the server itself. The software updates and virus scanning applications as well as patches will be implemented only on the server. At the same time, the servers will be the one to process information and store the information afterwards. Highly Reliable –Business organizations can expect continuous service for longer durations since thin clients can have a lifespan of more than five years. In as much as thin clients are built as solid state devices, there is less impact from wear and tear through constant use. Disadvantages of Thin Computing: Client Organizations are Subject to Limitations – Since the thin clients do most of their processing at the server, there will be setups where rich media access will be disabled. Some of these concerns are the result of poor performance when simultaneous access to multimedia on the thin client is taking place. Heavy and resource-hungry applications like Flash animations and video streaming can slow the performance of both the server and client. In corporate organizations where video conferencing and webinars are often  carried out, presentation of materials and web-cam/video communications can be adversely affected. Requires Superior Network Connection – Using a network that has latency or network lag issues can greatly affect thin clients. It can even mean rendering the thin clients unusable because the processing will not be fluently transmitted from the server to the client. This makes the thin client very hard to use in these cases since the response from the server will affect both the visual and the processing performance of the thin client. Even printing tasks have been observed to hog bandwidth in some thin client set-ups, which can affect the work going on in other units. A Thin Client Work Environment is Cost Intensive – For any plans of converting a regular work station into a thin client work environment, it is advised that comparative cost analysis be performed. Thin client set-ups have been noted to be cost efficient only if employed on a large-scale basis. Comparison of regular workstations using the same number of regular PC units should be made versus a work environment set-up that makes use of a dedicated server and the same number of thin clients. In some cases the cost of installing the server itself is already far more expensive than all the regular workstations combined. This is aside from the fact that a thin client unit can cost as much as a fully-equipped PC. Nevertheless, some argue that the benefits of thin clients, as far as cost and maintenance efficiency are concerned, will offset the initial costs. Besides, as a capitalized investment, the costs can be spread out for at least five years. Still, the excessiveness of the fees involving different licenses, which include software for every station, Client Access Licenses (CAL) for clients and server, as well as tracking and managing licenses, will tie up a substantial amount of business funds and may take too long to recover. Thus, smaller business organizations are advised to carefully consider such costs before venturing into server-based or thin client computing. Single Point of Failure Affects All – If the server goes down, every thin client connected to it becomes barely usable. No matter how many clients are connected, if the server becomes inaccessible, all work processes will come to a standstill thereby adversely affecting business-hour productivity. References http://research.microsoft.com/en-us/um/people/gray/moore_law.html http://en.wikipedia.org/wiki/Cloud_computing

Shadow Kiss Chapter 16

Sixteen â€Å"SO ARE YOU,† HE TEASED. â€Å"Yeah, but I just thought – â€Å" â€Å"That I was human? Because of the bite marks?† â€Å"Yeah,† I admitted. No point in lying. â€Å"We all have to survive,† he said. â€Å"And dhampirs are good at figuring out ways to.† â€Å"Yeah, but most of us become guardians,† I pointed out. â€Å"Especially men.† I still couldn't believe he was a dhampir – or that I hadn't spotted it right away. Long ago, dhampirs had been born from humans and Moroi getting together. We were half-vampire, half-human. Over time, Moroi started keeping themselves separate from humans. Humans grew too plentiful and no longer needed Moroi for magic. Moroi now feared they'd become human experiments if ever discovered. So no more dhampirs were being made that way, and in a bizarre genetic twist, dhampirs getting together with dhampirs couldn't make more dhampirs. The only way my race kept reproducing was through Moroi mixing with dhampirs. Normal logic would make you think that a dhampir and a Moroi would make children who were ? Moroi. Nope. We came out with perfect dhampir genes, half and half, mixing some of the best traits of both races. Most dhampirs came from dhampir women and Moroi men. For centuries, these women had sent their kids off to be raised somewhere else, so that the mothers could go back to being guardians. That's what mine had done. Over time, though, some dhampir women had decided they wanted to raise their children themselves. They refused to be guardians and instead banded together in communities. That's what Dimitri's mother had done. Lots of ugly rumors surrounded these women because Moroi men often visited in the hopes of getting cheap sex. Dimitri had told me that a lot of these stories were exaggerated and that most dhampir women weren't that easy. The rumors came from the fact that these women were almost always single mothers who had no contact with their kids' fathers – and because some dhampirs would let Moroi drink blood during sex. It was a kinky, dirty thing in our culture and was where the nickname for these non-guardian dhampirs had come from: blood whores. But I'd never even thought about a male blood whore. My mind was reeling. â€Å"Most guys who don't want to be guardians just run off,† I said. It was rare, but it happened. Guys bailed on guardian school and disappeared to hide out among humans. It was another disgraceful thing. â€Å"I didn't want to run off,† said Ambrose, seeming very cheerful about all this. â€Å"But I didn't want to fight Strigoi either. So I did this.† Beside me, Lissa was stunned. Blood whores stayed on the fringes of our world. Having one right in front of her – a guy, no less – was incredible. â€Å"This is better than being a guardian?† I asked in disbelief. â€Å"Well, let's see. Guardians spend all their time watching out for others, risking their lives, and wearing bad shoes. Me? I have great shoes, am currently massaging a pretty girl, and sleep in an awesome bed.† I made a face. â€Å"Let's not talk about where you sleep, okay?† â€Å"And giving blood isn't as bad as you think. I don't give as much as a feeder, but the high's pretty neat.† â€Å"Let's not talk about that either,† I said. No way would I admit that I knew Moroi bites were indeed â€Å"pretty neat.† â€Å"Fine. But say what you want, my life's good.† He gave me a lopsided smile. â€Å"But aren't people, like†¦well, aren't they mean to you? They must say things†¦Ã¢â‚¬  â€Å"Oh yes,† he agreed. â€Å"Horrible things. I get called a lot of ugly names. But you know where I get the most grief from? Other dhampirs. Moroi tend to leave me alone.† â€Å"That's because they don't understand what it's like to be a guardian, how important it is.† It occurred to me, with some unease, that I sounded exactly like my mother. â€Å"It's what dhampirs are meant to do.† Ambrose rose, unkinking his legs and giving me a face full of muscled chest. â€Å"You sure? How would you like to find out what you're really meant to do? I know someone who might be able to tell you.† â€Å"Ambrose, don't do it,† groaned Lissa's manicurist. â€Å"That woman's crazy.† â€Å"She's psychic, Eve.† â€Å"She's not psychic, and you cannot take the Dragomir princess to go see her.† â€Å"The queen herself goes to her for advice,† he argued back. â€Å"That's a mistake too,† grumbled Eve. Lissa and I exchanged looks. She'd latched onto the word psychic. Psychics and fortune-tellers were generally regarded with the same disbelief as ghosts – except that Lissa and I had recently learned that psychic abilities we'd previously believed to be fantasy were actually part of spirit. Hope that she might have stumbled onto another spirit user shot through Lissa. â€Å"We'd love to see a psychic. Can we go? Please?† Lissa glanced at a nearby clock. â€Å"And soon? We have a flight to catch.† Eve clearly thought it was a waste of our time, but Ambrose could hardly wait to show us. We put our shoes back on and were led out of the massage area. The spa rooms had been in a maze of halls behind the front salon, and we soon found ourselves in another maze that was farther back still. â€Å"There's no directory here,† I said as we walked past closed doors. â€Å"What are these rooms for?† â€Å"Everything and anything people will pay money for,† he said. â€Å"Like what?† â€Å"Ah, Rose. You're such an innocent.† We finally reached a door at the end of the hall. We stepped inside and found a small room that only held a desk. A closed door sat beyond it. A Moroi at the desk looked up, obviously recognizing Ambrose. He walked over to her, and the two got into a quiet argument as he tried to get her to let us in. Lissa turned to me, keeping her voice soft. â€Å"What do you think?† My eyes were on Ambrose. â€Å"That all that muscle's going to waste.† â€Å"Forget the blood whore thing already. I mean about this psychic. Do you think we've found another spirit user?† she asked eagerly. â€Å"If a party boy like Adrian can be a spirit user, then a woman who tells the future probably can be too.† Ambrose returned to us, grinning. â€Å"Suzanne was happy to fit you into the schedule before your flight. It'll be just a minute while Rhonda finishes up with her current client.† Suzanne didn't look very happy about fitting us in, but I didn't have time to ponder that because the inner door opened and an older Moroi man walked out, entranced. He gave Suzanne some cash, nodded at the rest of us, and left. Ambrose stood and made a wide sweeping motion toward the door. â€Å"Your turn.† Lissa and I walked inside the other room. Ambrose followed and closed the door behind us. It was like walking into someone's heart. Everything was red. Plush red carpet, a red velvet couch, velvet brocade wallpaper, and red satin cushions on the floor. Sitting on the cushions was a Moroi in her forties, with curly black hair and equally dark eyes. There was a very faint olive cast to her skin, but her overall look was pale, like all Moroi. Her black clothing stood out in stark contrast to the red room, and jewelry the color of my nails gleamed on her neck and hands. I expected her to speak in a spooky, mysterious voice – one with an exotic accent – but her words sounded blandly American. â€Å"Please, sit down.† She pointed to some cushions across from her. Ambrose sat on the couch. â€Å"Who've you brought?† she asked him as Lissa and I settled down. â€Å"Princess Vasilisa Dragomir, and her guardian-to-be, Rose. They need a fast fortune.† â€Å"Why do you always want to rush these things?† Rhonda asked. â€Å"Hey, it's not me. They have a plane to catch.† â€Å"It'd be the same if you didn't. You're always in a rush.† I shook off my awe of the room enough to pay attention to their easy banter and similar hair. â€Å"Are you guys related?† â€Å"This is my aunt,† said Ambrose fondly. â€Å"She adores me.† Rhonda rolled her eyes. That was a surprise. Dhampirs rarely had contact with their extended Moroi family, but then, Ambrose was hardly normal. Lissa was intrigued by all of this too, but her interest was different from mine. She was studying Rhonda intently, trying to find any indication that the woman might be a spirit user. â€Å"Are you a gypsy?† I asked. Rhonda made a face and began shuffling some cards. â€Å"I'm Roma,† she said. â€Å"A lot of people call us gypsies, though the term isn't exactly accurate. And really, I'm Moroi first.† She gave the cards a few more shuffles, then handed them to Lissa. â€Å"Cut, please.† Lissa was still staring, half-hoping she might see an aura. Adrian could sense other spirit users, but she didn't have that skill yet. She cut the cards and handed them back. Rhonda put the deck back together and dealt out three cards to Lissa. I leaned forward. â€Å"Cool.† They were tarot cards. I didn't know much about them, only that they supposedly had mystical powers and could tell the future. I didn't believe in that stuff much more than I'd ever believed in religion, but then, until recently, I'd never really believed in ghosts, either. The three cards were the Moon, the Empress, and the Ace of Cups. Ambrose leaned over my shoulder to peer at the cards. â€Å"Ooh,† he said. â€Å"Very interesting.† Rhonda glanced up at him. â€Å"Hush. You don't know what you're talking about.† She turned back to the cards and tapped the Ace of Cups. â€Å"You're on the verge of a new beginning, a rebirth of great power and emotion. Your life will change, but it will be a change that takes you in a direction that, while difficult, will ultimately illuminate the world.† â€Å"Whoa,† I said. Rhonda then pointed to the Empress. â€Å"Power and leadership lie ahead of you, which you will handle with grace and intelligence. The seeds are already in place, though there's an edge of uncertainty – an enigmatic set of influences that hang around you like mist.† Her attention was on the Moon as she said those words. â€Å"But my overall impression is that those unknown factors won't deter you from your destiny.† Lissa's eyes were wide. â€Å"You can tell that just from the cards?† Rhonda shrugged. â€Å"It's in the cards, yes, but I also have a gift that lets me see forces beyond what ordinary people can perceive.† She shuffled the cards again and then handed them to me to cut. I did, and she flipped three more over. The Nine of Swords, the Sun, and the Ace of Swords. The Sun card was upside down. Now, I knew nothing about this stuff, but I immediately got the feeling I was about to get a raw deal compared to Lissa. The Empress card had shown a woman in a long dress, with stars on her head. The Moon had shown a full moon with two dogs below it, and the Ace of Cups had shown a bejeweled chalice filled with flowers. Meanwhile, my Nine of Swords showed a woman sobbing in front of a wall of swords, and the Ace of Swords was a boring hand holding a plain iron sword. The Sun at least looked cheerful. It had what looked like an angel riding a white horse, with a brilliant sun shining above. â€Å"Shouldn't that be flipped right-side up?† I asked. â€Å"No,† she said, eyes on the cards. After several moments of heavy silence, she said, â€Å"You will destroy that which is undead.† I waited about thirty seconds for her to continue, but she didn't. â€Å"Wait, that's it?† She nodded. â€Å"That's what the cards say to me.† I pointed at them. â€Å"Seems like they've got a little bit more to say than that. You gave Lissa a whole encyclopedia worth of information! And I already know I'm going to kill the undead. That's my job.† Bad enough I'd gotten a minuscule fortune. It was also totally unoriginal. Rhonda shrugged, as though that were some sort of explanation. I started to say that she'd better not even think about charging me for that crap reading when there was a soft knock at the door. It opened, and to my surprise, Dimitri stuck his head inside. His eyes fell on Lissa and me. â€Å"Ah, they said you were in here.† He walked in and noticed Rhonda. To my further surprise, he gave her a low nod of respect and said very politely, â€Å"I'm sorry to interrupt, but I need to bring these two to their flight.† Rhonda examined him – but not in a checking-him-out kind of way. It was more like he was mystery she wanted to figure out. â€Å"There's nothing to apologize for. But maybe you've got time for a reading of your own?† With our similar views on religion, I expected Dimitri to tell her he had no time for her scam-artist fortune-telling. Yet the look on his face stayed serious, and he finally nodded, sitting down beside me, letting me smell the sweet scent of leather and aftershave. â€Å"Thank you.† His words were still perfectly polite. â€Å"I'll be brief.† Rhonda was already shuffling up my useless cards. In record time, she had them ready for cutting and had dealt out three cards in front of Dimitri. The Knight of Rods, the Wheel of Fortune, and the Five of Cups. I couldn't get a feel for these. The Knight of Rods was what it sounded like, a man on horseback with a long wooden spear. The Wheel of Fortune was a circle with strange symbols floating in the clouds. The Five of Cups showed five knocked-over cups spilling some kind of liquid out while a man stood with his back to them. Her eyes flicked over the cards, looked at Dimitri, then looked back at the cards. Her expression was blank. â€Å"You will lose what you value most, so treasure it while you can.† She pointed to the Wheel of Fortune card. â€Å"The wheel is turning, always turning.† The reading wasn't as good as Lissa's, but he'd gotten a hell of a lot more than me. Lissa elbowed me in a silent warning to be quiet, which startled me at first. Without even realizing it, I'd opened my mouth to protest. I shut it and glowered. Dimitri's face was dark and thoughtful as he stared at the cards. I didn't know if he knew anything about this stuff, but he was staring at the images as though they really held all the secrets of the world. At last, he gave Rhonda another respectful nod. â€Å"Thank you.† She nodded back, and then the three of us rose to catch our flight. Ambrose told us the readings were on him and that he'd settle up with Suzanne afterward. â€Å"It was worth it,† he told me. â€Å"Worth it to see you think twice about your fate.† I scoffed. â€Å"No offense, but those cards didn't make me think much about anything.† Like everything else, this just made him laugh. We were about to leave Suzanne's little waiting room when Lissa suddenly dashed back to Rhonda's open doorway. I followed after her. â€Å"Um, excuse me,† Lissa said. Rhonda looked up from more shuffling, her face troubled. â€Å"Yes?† â€Å"This is going to sound weird, but†¦um, could you tell me what element you specialized in?† I could feel Lissa holding her breath. She so, so wanted Rhonda to say she hadn't specialized, which was often the sign of having spirit. There was still so much to learn, and Lissa loved the ideas of finding others who could teach her – and she especially loved the idea of someone teaching her to foretell the future. â€Å"Air,† said Rhonda. A soft breezed rustled through our hair to prove the point. â€Å"Why?† Lissa let go of her breath, disappointment washing over me through her link. â€Å"No reason. Thank you again.†

Skidelsky Warwick Lecture

In my third and fourth lectures examine the monetary and fiscal confusion which as reigned in the last five years -the experiments with ‘unorthodox monetary policy' and the austerity drive in fiscal policy -as policy makers sought a path to recovery. In my fifth lecture 1 kick at the causes Of the crisis from the standpoint of the world monetary system. Finally, I ask the question: what should post-crash economics be like? What guidance should economics offer the policy-maker to prevent further calamities of the kind we have just experienced?What should students of economics be taught? In this lecture I will consider only those bits of pre-crash orthodoxy relevant to policy making, tit main emphasis being on UK developments. Theories of expectation formation played an overwhelming parting shaping the theory of macroeconomic policy; with changes in the way economists modeled expectations marking the different phases of theory. I will treat these in roughly chronological order, s tarting with the Keynesian theory. II.UNCERTAIN EXPECTATIONS Keynesian macro theory dominated policy from roughly 1945-1975. The minimum doctrine -not in Keynes, but in accepted versions of Keynesian theory -to justify policy intervention to stabilize economies is: SLIDE 1 1. Uncertain expectations, particularly important for investment, leaving investment to depend on ‘conventions' and ‘animal spirits'. 2. Relative interest-inelastic of investment. 3. A) sticky nominal wages (unexplained) and b) sticky nominal interest rates (explained by liquidity preference).The first point suggested investment was subject to severe fluctuations; the last suggested there was a lack or weakness of spontaneous recovery mechanisms- ii the possibility of ;under-employment equilibrium'. This led to a prescription for macro-policy: to prevent or minimize fluctuations of investment demand. Point 2 in combination with b suggested primacy of fiscal over monetary policy for stabilization. SLIDE 2 ‘For Keynes, it was the tendency for the private sector, from time to time, to want to stop spending and to accumulate financial assets instead that lay behind the problems of slumps and unemployment.It could be checked by deficit spending'. (C J. Also and D. Makes (1985), in D. Morris (De. ) ‘The Economic System in the UK†, 374) ‘In the standard Keynesian economic model, when the economy is at less than full capacity, output is determined by demand; and the management of economic activity and hence employment is effected by managing demand'. (ibid, 370) Mention in passing, that there was a theoretical and social radicalism in Keynes obliterated in the standard postwar Keynesian model.For example, he thought insufficient demand was chronic and would get worse; and that, in consequence, the longer term survival of a free enterprise system depended on the redistribution of wealth and income and the reduction in hours of work. I will return to these points in my last lecture. Demand- management The government used fiscal policy (variations in taxes and spending) to maintain full employment, while keeping short term interest rates close to some ‘normal' (or expected) level. Eel. Monetary policy was largely bypassed as a tool of demand-management.The government forecast real GAP for the following year by forecasting year on movement of its expenditure components: consumption, fixed capital formation, stock building spending, and net exports. Budget deficits then adjusted to maintain full employment. There was no explicit modeling of expectations, though attention was paid to the issue of ‘confidence'. The prevalent view was that the confidence of the cuisines community was best maintained by a commitment to full employment. It was different with the balance of payments.With sterling convertible into foreign currencies at a fixed exchange rate, governments also needed to retain confidence of non-resident holders of sterling, so the two requirements of confidence might pull in different directions. ‘Stop-Go' was the result. Stop-Go not withstanding, fiscal activism proved highly successful, aided by the long post-war boom. The budget remained in surplus with current account revenues exceeding expenditure and with borrowing mostly stricter to finance public investment not covered by current-account surpluses.Chancellors from Crisps to Macmillan were even tempted to extend this-above-the-line surplus to an overall surplus by covering capital expenditure below the line from revenue yet this was not achieved 1 . Nonetheless, the public-sector borrowing requirement (ESP.) fell from an average of 7. 5% of GAP (1952-1959) to 6. 6% of GAP (1960-1969). The national debt-to-income ratio fell from 3:1 in 1950 to 0. 7:1 in 19702. Unemployment was consistently below 2. 5% and inflation was low. Ill. THE RISE AND FALL OF PHILLIPS CURVE KEYNESIAN The post-war problem turned out to be not unemployment but inflation. With full capacity utilization, whether generated by Keynesian policy or by benign world conditions, there was always going to be pressure on prices. So the attention of Keynesian policymakers was increasingly turned to fighting inflation, using both fiscal and monetary tools. In this they were also successful for a time. But from the late asses, inflation started to creep up; and the unemployment cost of restraining it started to rise: we enter the era of ‘stagflation'. The underlying theoretical question was: what caused inflation? Was it excess demand or ‘cost-push'?There was no single Keynesian answer to this question. Some Keynesian economists argued that labor market was like any other, with price being determined by the balance between supply and demand. A reduction in the demand for labor would lower its price. Deflation would slow the rise of nominal wages, and hence a rise in the general price level. The question of course was how much deflation would be needed for stable prices? This was not an easy case for Keynesian to argue. Given their belief in sticky nominal wages, the unemployment cost might prove very high.Most Keynesian economists were more comfortable with the ‘cost push' theory of inflation: unions pushing up wages ahead of productivity. Prices rose because business managements raised them; managements raised prices because their costs had risen; costs rose owing to pay increases; and pay increased because otherwise unions would come out on strike. Higher unemployment would not stop them because most of the unemployed could not do the strikers' jobs. In fact, cost-push could occur at levels well below full employment.Short of bringing back mass unemployment, deflating demand would not stop inflation. What was required was a compact with the unions to restrain pay push: incomes policies. Anti-inflation policy in the 1 sass and asses wobbled between fiscal and monetary measures to restrain demand and attempts to reach pay deals with the unions. The Keynesian were rescued from this dilemma by the econometric work Of A. W. Phillips. In 1 958, A. W. Phillips published a famous article which claimed to demonstrate a well-determined relationship between the unemployment rate and the rate of wage increases.The Phillips Curve implied that there was a stable trade-off between unemployment and inflation. The prize was price stability with a small increase in unemployment, way short of the depression. More generally, policy-makers were supposed to have a ‘menu of choice' between different rates of inflation and unemployment. SLIDE 3. ORIGINAL PHILLIPS CURVE The Keynesian policy of demand-management unraveled with the attack on the Phillips Curve by Milton Friedman of Chicago University. In a single lecture in 1 968, he demolished Phillips Curve Keynesian and started the monetarist counter-revolution.Adaptive Expectations Friedman restated the pre-Keynesian idea that there was a unique equilibrium rate of unemployment which he called the ‘natural rate'. Inflation was caused by government attempts to reduce unemployment below the natural rate by increasing the amount of money in the economy. Friedman accepted that there was a trade-off between inflation and unemployment, but that it was temporary, and existed only because workers were fooled into accepting lower real wages than they wanted by not taking into account the rise in prices.But if government repeatedly resorted to monetary expansion (for example by running budget deficits) in order to educe unemployment below its ‘natural' rate, this ‘money illusion' would disappear and workers would put in increased wage demands to match the now expected rise in prices. In short, after a time workers developed inflationary expectations: they built the expected inflation into their wage bargaining. One could not use the Phillips Curve to control inflation in the long run since the Curve itself shifted due to the level of inflation rising. SLIDE 4.FRIEDMAN'S EXPECTATIONS AUGMENTED PHILLIPS CURVE SLIDE 5. One simple version of adaptive expectations is stated in the following equation, where pee is the next year's rate of inflation that is currently expected; p-Eel is this year's rate of inflation that was expected last year; and p is this year's actual rate of inflation: where is between O and 1. This says that current expectations of future inflation reflect past expectations and an â€Å"error-adjustment† term, in which current expectations are raised (or lowered) according to the gap between actual inflation and previous expectations.This error-adjustment is also called â€Å"partial adjustment. † Friedman's work had huge anti-Keynesian policy implications. The five main Ones Were: First, macro-policy can influence nominal, but not real variables: the price level, not the employment or output level. Second, Friedman re-stated the Quantity Theory of Money, the theory that prices (or no minal incomes) change proportionally with the quantity of money. Conversely, fiscal ‘fine tuning' operates with ‘long and variable lags': it is liable to land the economy in the wrong place at the wrong time.Consequently, such stabilization as was needed is much better done by monetary policy than fiscal policy. It lies within the power of the central bank, but not the Treasury, to keep nominal income stable. Provided the government kept money supply growing in line with productivity there would be no inflation, and economies would normally be at their ‘natural rate' of unemployment. Third, Friedman argued that ‘inflation was always and only a monetary phenomenon'.It was the total money supply in the economy which determined the general price level; cost pressures were not independent sources of inflation; they had to be validated by an accommodating monetary policy to be able to get away with a mark-up based price determination strategy; Fourth, Friedman's p ermanent income hypothesis -dating from the early 9505 -suggested that it is households' average long-run income (permanent income) that is likely to determine total demand for consumer spending, rather than fluctuation in their current disposable income, as suggested by the Keynesian consumption function.The reason for this is that agents Want smooth consumption paths. This implied that the degree of self-stabilization of the economy was greater than Keynes suggested, and that consequently multipliers were smaller. Keynesian tried to fight the monetarist onslaught by strengthening Keynesian micro-foundations, especially of observed nominal rigidities. They plopped models with ;menu costs', ‘insider-outsider' labor markets, ‘asymmetric information'. These kept the door open for policy interventions to sustain aggregate demand. Nevertheless, Friedman's impact on macro-policy was swift and decisive.SLIDE 6 ‘We used to think that you could spend your way out of a rece ssion, and increase employment by cutting taxes and boosting Government spending. Tell you in all candor that that option no longer exists, and that in so far as it ever did exist, it only worked on each occasion since the war by injecting a bigger dose of inflation into the economy, followed by a higher level of employment as the next step'. Prime Minister James Callaghan (1976), Leader's speech, Blackball ‘The conquest of inflation should be the objective of macroeconomic policy.And the creation Of conditions conducive to growth and employment should be the objective of microeconomic policy'. Chancellor of Exchequer Engel Lawson (1 984), Mass Lecture Discretionary demand-management was out; balanced budgets were back. The unemployment target was replaced by an inflation target. The ;natural' rate of unemployment was to be lowered by supply-side policies, which included legislative curbs on trade unions. V. RATIONAL EXPECTATIONS AND THE NEW CLASSICAL ECONOMICS With rational e xpectations we enter the world of New Classical Economics. RE is the ‘radical wing of monetarism†¦ Est. known for the startling policy conclusion †¦ that macro-economic policies, both monetary and fiscal, are ineffective, even in the short-run'4. Rational expectations first appeared in the economic theory literature in a famous article by J. Mouth in 1961, but only filtered through to policy discussion in the early 1 sass with the work of Robert Lucas and Thomas Sergeant on business cycles, and Eugene Fame on financial markets. The Lucas critique Of adaptive expectations (1976) put paid to the idea Of an exploitable trade-off between employment and inflation.Friedman's adaptive expectations rely on gradual adjustment of expectations to the experienced behavior of a variable. But our knowledge includes not just what we have experienced but current pronouncements of public authorities and theoretical knowledge of aggregate relationships. For example, the Minister of Fi nance announces that he will increase money supply by 10% a year to stimulate employment. STEM tells us that an increase in the money supply will ease prices proportionately. So it is rational to expect inflation to be a year.All nominal values -interest rates, wage rates- are instantly adjusted to the expected rate of inflation. There is not even a brief interval of higher employment. Friedman's distinction between a Keynesian short run in which agents can be fooled and a Classical long run in which they know what to expect disappears. Adaptive behavior is a description of irrational behavior if agents know what to expect already. Notice though that in this example, rational expectations is defined as belief in the STEM.SLIDE 7 Expectations, since they are informed predictions of future events are essentially the same as the predictions of the relevant economic theory†¦ Expectations of firms (or more generally, the subjective probability distribution of outcomes) tend to be di stributed for the same information set, about the prediction Of the theory (or the ‘objective' probability distribution Of outcomes)' (G. K Shaw (1 984), 56) Formally, the rational expectations hypothesis (ERE) says that agents optimally utilities all available information about the economy and policy to construct their expectations.As such, such they have ‘rational' expectations. They are also rational in that they use their expectations to maximize their utility or profits. This does not imply that agents never make mistakes; agents may make mistakes on occasion. However, all that is there to be learnt has already been learnt, mistakes are assumed to be random, so that agents are correct on average. Agents learn the true value of parameters through repeated application of Bases' theorem. Eel they turn their subjective bets into objective probability distributions.An equivalent statement is that agents â€Å"behave in says consistent with the models that predict how th ey will behave†6. Since the models contain all the available information, ii. They are rational expectations models, following the model minimizes the possibility of making expectation errors. At the core of the rational expectations hypothesis is the assumption that the model of the economy used by individuals in making their forecasts is the correct one -that is, that the economy behaves in a way predicted by the model.The math is simplified by the device of the Representative Agent, the sum of all agents, possessed of identical information and utility preferences. This micro-economic device means that the framework can be used to analyses the impact of policies on aggregate welfare, as welfare is the utility of the agents. The implication of the ERE is that outcomes will not differ systematically from what people expect them to be. If we take the price level, for instance, we can write: SLIDE 8 This says that the price level will only differ from the expectation if there is a surprise.So ex ante, the price anticipated is equal to the expectation. [E[P] is the rational expectation based on all information up to date; is the error ERM, which has an expected value of zero, and is independent of the expectation. With rational expectations the Phillips Curve is vertical in the short-run and in the long-run. SLIDE 9. THE SERGEANT-LUCAS PHILLIPS CURVE. With rational expectations, government action can affect real variables only by surprise. Otherwise they will be fully anticipated. This rules out any fiscal or monetary intervention designed to improve an existing equilibrium.More generally ‘any portion Of policy that is a response to publicly available information -such as the unemployment rate or the index of leading indicators -is irrelevant to the real economy' 7. Policy can influence real variables only by using information not known to the public. The Efficient Market Hypothesis The application of rational expectations to financial markets is know n as the â€Å"Efficient Market Hypothesis† (MME), made popular by Eugene Fame (1970, 1976). The MME postulates that shares are always correctly priced on average because they adjust instantaneously and accurately to any newly released information.In the words of Fame, â€Å"l take the market efficiency hypothesis to be the simple statement that security prices fully reflect all available information† 8. So prices can't be wrong because if they were, someone would seek to profit from the error and correct it. It follows that according to the efficient market hypothesis, it is impossible to consistently achieve returns in excess of average market returns (beat the market). In an RE joke, two economists spot a $10 bill on the ground. One stoops to pick it up, whereupon the other interjects, ‘Don't.If it were really $1 0, it wouldn't be there anymore. † The efficient market hypothesis is the modern manifestation of Adam Smith's ‘invisible hand'. Increase d regulation can only aka markets less efficient because regulators have less information than those engaged in the market, risking their own money. There are different versions of the efficient market hypothesis. In its ‘weak' form, investors make predictions about current prices only using historical information about past prices (like in adaptive expectations).In its ‘semi-strong' form, investors take into account all publicly available information, including past-prices. (This is the most ‘accurate' and the closest to rational expectations). In its ‘strong' form, investors take into account all information that can possibly be known, including insider information. Rational expectations models rely heavily on math. Lucas defined expectations as the mean Of a distribution of a random variable. The greater the number of observations of a random variable, the more likely it is to have a bell shaped or Normal distribution.The mean of the distribution, in ordin ary parlance the average of the observations, is called the Expectation of the distribution. In the bell-shaped distribution, it coincides with the peak of the bell. Those who are supposed to hold Rational Expectations (ii all of us) are assumed to know how the systematic parts of he model determine a price. We use that knowledge to generate our prediction. This will be correct except for random influences. We can assume that such random events will also adhere to the bell-shaped distribution and that their mean/expectation will be zero.Thus the systematic or deterministic prediction based on theory is always correct. Errors have zero expectation. The tendency of the MME, as is readily seen, is to rule out, or minimize, the possibility Of bubbles -and therefore crashes; more generally to rule out the possibility of crises being generated within the financial system: historically he most important source of crises. This being so, policy did not have to pay much attention to banks. Fo llowing the acceptance of the MME, the financial system was extensively De-regulated.Real Business cycle DOGS DOGS modeling takes root in New Classical macroeconomics, where the works of Lucas (1975), Jutland and Prescott (1982), and Long and Peoples (1983) were most prominent. The earlier DOGS models were pure real business cycle (RIB) models. ii models that attempted to explain business cycles in terms of real productivity or consumption shocks, abstracting from money. The logic behind RIB models is clear. If money cannot affect real variables, the source of any disturbance to the real economy must be non-monetary.If we are all modeled as having rational expectations, business fluctuations must be caused by ‘real' and ‘unanticipated' ‘shocks'. (Notice the use of word ‘shock'). These shocks make the economy dynamic and stochastic. Unemployment is explained in these models by rational adjustments by workers of their work/leisure trade off to shifts in product ivity. This is a fancy way of saying that there is never any unemployment. As a result of continuously re-optimizing agents, economies in DOGS models re always in some form of equilibrium, whether in the short run or long run.The economy always starts from an equilibrium position, and even when there is a shock, it immediately jumps onto an equilibrium time path – the saddle path. So the economy never finds itself in a position of disequilibrium. SLIDE 10 ‘The model provides an example of an economy where real shocks drive output movements. Because the economy is Wallabies, the movements are the optimal response to the shocks. Thus, contrary to the conventional wisdom about macroeconomic fluctuations, here fluctuations do not reflect NY market failures, and government interventions to mitigate them can only reduce welfare.In short, the implication of real-business cycle models, in their strongest form, is that observed aggregate output movements represent the time-varyi ng Parent optimum'. (Roomer (2011 ) â€Å"Advanced Macroeconomics†, 204) Translated into English: depressions are optimal; any attempt to mitigate them will only make things worse. Later came the New Keynesian who preserved the basic framework of the New Classical RIB/DOGS models, but added ‘market frictions', like monopolistic competition and nominal rigidities, to make the models more applicable to the real world. Critiques: 1 .The fundamental criticism is that this whole class of New Classical models carries an intellectual theorem -that agents are rational optimizers – to an extreme and absurd conclusion. By postulating complete information and complete markets, ii. By abolishing Keynesian or Knighting uncertainty, they cut off enquiry into what might be rational behavior under uncertainty -such as ‘herd behavior'. They also exclude irrational expectations. Behavioral economics only really took off after the crisis. 2. The aim of New Classical economics was to unify macro and micro by giving macro-economic secure micro-foundations.Macroeconomic models should be based on optimization by firms and consumers. But New Classical models are not well grounded in micro-economics since their account of human behavior is seriously incomplete. 3. Ay defining rational as the mean of a random distribution, the New Classical models rule out as too exceptional to worry about ‘fat tails' – that is extreme events with disproportionately large consequences. 4. The vast majority of DOGS models utilities log-landslides utility functions which eliminate the possibility of multiple equilibrium. 1 5. New Classical models have no place for money, and therefore for money hoarding, which depends on uncertainty. In pure DOGS models there is no financial sector. DOGS models depend on what Goodhearted calls the ‘transversally condition', which says that â€Å"by the end of the day, or when the model stops, all agents shall have repaid all their debts, including all the interest owed, with certainty. In other words, when a person dies he/she has zero assets left' 12. Defaults cannot happen. This is another kind of logical madness.

Answer questions from articles Essay Example | Topics and Well Written Essays - 750 words

Answer questions from articles - Essay Example Schor explains that these statistics underpin the need for the revival of the discourse that will call all individuals and households to reconsider their material requirements. In order for this right to be enforced, she suggests that governments should guarantee their citizens of employment, supply their basic needs, and consider using government income vouchers or transfers (Schor 7). A second element that Schor believes can help overcome the problems in American consumerism is an emphasis on quality of life rather than quantity of stuff. Schor states that it was in the 1970s that the indicators of the quality of the life of Americans stopped reflecting their incomes and the country’s Gross Domestic Product. She states that there is evidence suggesting that earning an income above the poverty line does not necessarily improve an individual’s well-being. She asserts that the lack of emphasis on well-being among the people above the poverty line is an indication of people’s concern with relative rather than absolute income. She states that an alternative explanation to the unlikely relationship between income and well-being could be the fact that increased output undermines factors yielding welfare (Schor 7). She observes that this is seen in the increase in work time, the decline in family leisure and time for one’s community. She offers that these two things exemplify the inverse relationship between growth and social capital. Growth and increased materialism affects a person’s appreciation of personal meaning, social commitment, community, religion, and family, all of which are alternative sets of values. She advises that the labor market should be restructured to allow workers more time to themselves and that companies that require their workers to work for excessive hours should be penalized. Schor believes that this will serve as an alternative indicator of GNP,

The central concepts of finance Essay Example | Topics and Well Written Essays - 3000 words

The central concepts of finance - Essay Example In this case therefore, as argued by Bodie, et al, (2011), if the market is not able to predict its fluctuations, but does asses them as being likely or less likely, then the likelihood can be accessed through mathematical process using the relevant information in the market. Thus, factors such as price reflect all the relevant information that is available in terms of the total value of an asset. With the introduction and analysis of the financial efficiency, this paper provides a comprehensive analysis of the market efficiency types and the approaches to test this efficiency. After the emergence of stock market, there was a widespread concern and controversy that made most of the investors to be keen when participating in the market. The situation was caused by the fact that their approach of making their profits seemed inappropriate. Considering that the stock market is an important component of the capital market, many economists in the world developed serious concerns and intere sts in exploring the trend of stock price. In this case, even though the intentions were different, there has been a central focus on the trend of the capital market in the global financial market. As the efficient market hypothesis became known to many, it became also an important part of the school of rational expectations theory, and one of the theoretical foundations of modern economic principles. As argued by the America financial economist, Fama (1965), if the market price fully reflect the all of available information.

MGMT670 Week 4 Conf Assignment Example | Topics and Well Written Essays - 500 words

MGMT670 Week 4 Conf - Assignment Example A second situation in which SWOT analysis would be useful for the company is to evaluate other companies. A few years ago the firm was looking for a strategic to form a marketing alliance. The executive management team of the company utilized SWOT to evaluate the different partner alternatives. â€Å"SWOT chart can help to uncover opportunities that your company is well placed to take advantage of† (Smith, 2006). A third potential application of SWOT analysis is that it can be used to analyze different locations for international expansion. To fully analyze external opportunities an analyst has to monitor the key macroeconomic forces which are demographic-economic, technological, political-legal, social-cultural (Kotler, 2003). The identification of the strengths of a company can be used to formulate plans and operational procedures to improve the efficiency and profitability of a company. The analytics of opportunities can help an organization gain a competitive advantage. Analyzing the threats of a company is crucial to adequately incorporate a risk management plan. It can also help firms mitigate and resolve problems when they occur through proper strategic planning. Our firm should expand the use of SWOT beyond the executive management team in order to take full advantage of the capabilities and reach of this powerful managerial tool. SWOT analysis is a great tool, but it does have its limitations. For instance the use of SWOT does not provide alternative solutions to managers for specific problems. The analysis is too broad base which hinders the ability of a firm to solve specific problems that are hurting the efficiency, productivity, and profitability of the company. Project management requires the ability of the project managers and his team to prioritize specific issues. The use of SWOT does not help the leader

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Employment Law - Independent Contract Case Study - Essay Example The IRS defines an employee using existing common-law rules (IRS P-15a 4). The IRS maintains that it makes no difference how you label the relationship because the relationship between the employer and the person performing the service defines the relationship (IRS P-15a 4). The relationship that existed between Ark Bark and Joshua was bound by an oral agreement which was not put to writing. The employer, according to the case study, maintained an employer/employee relationship with Joshua by staying in frequent contact with him via telephone. It demonstrates that the employer, not Joshua, was in charge of maintaining the relationship that existed between them. The IRS tells us to examine the element of behavioral control between the parties (IRS P-15a 6). Behavioral control, whether it rests with the employer or the person performing the service, is significant in identifying the nature of the relationship. Behavioral control establishes â€Å"[†¦] whether a business has the right to direct and control how the worker does the task for which the worker is hired [†¦] (IRS P15a 6).† An employee, the IRS states, must generally follow the employer’s instructions on when, how, and where to perform the work (IRS P-15a 6). The employer gives the employee these instructions, that normally include the tools to use in performing the work, identifies who will assist the employee in accomplishing the work, where the employee must purchase or receive the relevant supplies and equipment necessary to perform the work, who performs each component of the task and in what order of priority it is performed (IRS P-15a 6). In the case study presented, we cannot say the employer issued directions to Joshua on when, how, and where to perform the work because we do not know the substance of the sixty-eight telephone calls made to Joshua by Ark Bark’s vice president. The employer did not provide Joshua the tools to perform the sales work, although

Management of Working Capital Essay Example | Topics and Well Written Essays - 1500 words

Management of Working Capital - Essay Example A discussion relating to working capital cycle, methods of managing working capital, working capital management in UK companies and suggestions for improvement has been presented below. The working capital of the business is defined as the net of current assets over current liabilities. It is an important liquidity measure of the firm. The current assets include not only cash, receivables but also inventories as it can be easily liquidated whereas the current liabilities include short term loans and creditors (University of California, n.d.). A business with scarce working capital faces difficulty in meeting its short term obligations from the available cash resources if there is a sudden or continuous fall in sales. Therefore, it is important to maintain an optimum amount of working capital in the business and it must be carefully monitored by the managers (Nix & McFetridge, n.d.). Working capital forms an important part of a firm’s operations. Maintaining an ideal level of inventory ensures that the firm does not have to face the problem of material deficit in meeting its production targets. Similarly the receivables figure in the balance sheet indicates the willingness of the firm to extend goods on credit. As credit sale is risky the management must be careful in the choice of debtors. Working capital consists of current assets like cash, inventory and current liability like creditors and short term loans. The pattern of all the above components of working capital varies with the business cycle. When there is a fall in the market demand there is a rise in the stock of finished goods. Later when this fall in demand takes the form of recession the firm lowers the stock of inventories, delays the payment of loans and accelerates the realization of receivables. This implies that with the worsening of the recession there is a decrease in the working capital. Therefore the efficient management of working

Response Strategies Assignment Example | Topics and Well Written Essays - 500 words - 1

Response Strategies - Assignment Example This is done so as to encourage the idea that a security breech would be difficult to bring about. Deterrence is usually practiced in all private and government agencies where security personnel are required to be on their feet at all times, to conduct random patrols and to react effectively to any possible intrusions. In this way an impression of high security is created in order to deter a possible attack. However, this method is only affective for low-level threats that are less motivated from the start, and may not be as effective against high-risk threats that are carefully maneuvered by the criminals. Denial Strategies are often used for the security of certain materials and equipments, for example, hazardous chemicals, nuclear weapons, explosives etc. Since use or release of these materials can put the common public at risk, a denial strategy is applied by which access to such material is prohibited. In order to prevent any sort of breech, highly trained and armed security per sonnel are positioned so as to ensure timely reaction against any attack. Containment strategy is applied against theft of an asset. This strategy is usually practiced in places like banks and museums where valuable assets are in danger of being stolen.

Overweight and Obesity Among Adults in the US Essay

Overweight and Obesity Among Adults in the US - Essay Example The statistics mentioned in this essay represents the rate of obesity in the United States according to statistics of 2010 among adults who are 20 and older (National Institute of Diabetes and Digestive and Kidney Diseases, 2012). It can be seen that rate of obesity is relatively higher in ethnic groups as compared to Whites in different categories of obesity. If analyzed in the light of causes mentioned above, it can be seen that ethnic groups have relatively lower access to a healthy lifestyle. Prime reasons of it can be less income, residence in the neighborhoods where availability of healthy food and fresh produce is not possible and other social and cultural factors leading to obesity (Centers of Disease Control & Prevention, 2013). In addition to that, ethnic groups like African Americans and Hispanics have cultural preferences for larger portions and family meals contributing to the overall increase in weight (Lutfiyya, Garcia, Dankwa, Young & Lipsky, 2008). As far as sedentar y lifestyle is concerned, the rate of multiple jobs is higher in ethnic groups requiring more time to be spent on job curtailing the rate of physical activity. Furthermore, low median income groups also sustain lower access to nutritional food due to increasing cost of fresh edible items and also easy availability of junk food (Lutfiyya, Garcia, Dankwa, Young & Lipsky, 2008). The higher rate of both parents employment is also present in ethnic minorities which also makes utilization of junk food a viable option. Furthermore, deprived neighborhoods also have the poor infrastructure in which recreational spaces are also limited. A considerable amount of research also indicates that individuals from ethnic groups are more susceptible to mental conditions like clinical depression which is more likely to trigger binge eating (Fuchs, 2011). Research also states that factors such as commercialism on food, increased screen time and complex work arrangements are likely to affect ethnic minor ities more as compared to Whites.

The Main Forces of the United States Essay Example | Topics and Well Written Essays - 1500 words

The Main Forces of the United States - Essay Example This motive had been echoed earlier on by Beveridge when he stated that ‘it may be that we will not annex the Philippines, Hawaii, and Cuba: but events will annex them†¦Ã¢â‚¬â„¢ (Ayers, 2009). The forces that were instrumental in this movement were the politicians and other state leaders who wanted to see the United States become an imperial power. Initially, Americas’ involvement in the war was purely humanitarian. They wanted to offer their support to the Cubans who were fighting for their independence against the Spanish Navy. However, their change after a presidential decree by McKinley who wanted to assist the Cubans to gain their freedom from the Spaniards (Ayers, 2009, p 489). This interference brought them to war with the Spanish Navy, a war which they wore due to their superior Navy skills and equipment. It was after this conflict with the Spanish that the Americans sought to acquire more territory in areas such as Philippines and Hawaii. They wanted to rid of European rule in these nations and spread their own beliefs and practices. Among the notable voices of imperialism was that of Albert Beveridge. Even at a young age, his superior oratory skills made him the focus of attention. He had been quoted championing for imperialism on a number of occasions, the most memorable being his argument that America needed to spread its liberty, civilization and the kingdom of God here on earth. It is such remarks that have been echoed by the American foreign policy, even to this day. At first, the United States was separated geographically from the rest of the European countries, thus could not participate in the acquisition. Additionally, it was guided by the Monroe Declaration that prohibited it from interfering with the affairs of other nations. The only exception was when they stepped in to offer humanitarian aid to the affected nations.

Clothes In Latin America Essay Example for Free

Clothes In Latin America Essay Clothes in Chile and general Latin America Clothing styles throughout Latin America vary from region to region and have been influenced through several different sources. Fashion in Latin America today and traditional fashions of Latin America differ dramatically. Climate, location, isolation, population, economy, history, colonial influences are many of the sources that have helped to contribute to these changes. Traditional Latin American fashion varied form region to region but maintained a distinctive appearance. Traditional and new aged Latino fashions are generally easy to decipher from each other. Modern fashion in Chile and most of Latin American have lost their traditional roots and are similar to North American. It has become the norm to see a citizen of Chile walking the street in Gap or American eagle. The amount of traditional roots left in clothes largely depends on the location. Rural Latin American and Chile clothes are much more traditional than in the cities. Rural Chileans and Latin Americans who live in tropical climates prefer lightweight cotton clothing in general. Men usually wear lightweight cotton clothing and loose fitting cotton shirts. The majority of the woman dress in long skirts and blouses. In contrast, people who live in mountains or places of high elevation need heavier clothing for protection against the cold. Both men and woman alike wear ponchos or will simply use blankets with a slit for the head. Woman also dress in full skirts, long sleeved blouses, and shawls. Different lifestyles require different sorts of fashion. Farmers wear straw or felt hats to protect themselves form the sun. In the highlands men often wear coarse hand woven shirts and baggy pants. Rural people generally go barefoot or in sandals, and some even make shoes out of automobile tires. Despite modernized fashion Chileans and other Latin Americans, will dress more traditionally for special events or occasions. Chilean cowboys (Hausas) wear big flat-topped hats, heavy ponchos, colorful sashes, fringed leather leggings, and boost with spurs. This is a traditional outfit for Hausas in Chile. The clothing of the Araucarias Indian women of south-central Chile includes brightly colored shawls and heavy silver jewelry. Many Indian groups wear brightly colored clothing with traditional patterns. In such groups, each area/village has its own special designs and colors. Colonials played a large and important role in the alteration and adaptation of Latin American fashion. The cultures different styles of clothing mixed together and became more European/American as time went on. Over the years factories have bee built throughout Latin America and Chile, many of which produced clothes, influencing fashion further. Media greatly promoted the Americanization of clothes in the Hispanic culture as well. Different regions have held on to their native clothes styles better than others. Traditional clothing, however, can still be found in certain areas of Latin America today. Areas that are more isolated than others have a better chance of holding on to their traditional way of dress. Because these regions are isolated they have not been as colonized as other areas and are visited by outside locations less often. Even if a location isn t necessarily isolated the physical characteristics and weather can cause traditional dress to continue. Extreme heat of cold, high winds, and a rocky area of land are examples of factors that cause modernization to decrease. Clothes worn in Latin American countries today differ greatly from region to region. In Ecuador the Otovindions are well known for their distinctive weave pattern, bright colors, and sharp depiction of figures in their clothing. Clothes in Ecuador and many other Latin American countries are hand made to a larger extent than in America. Bolivia is very much in touch with their traditional roots in clothing today. Many men and boys wear brightly colored knitted caps with earflaps, which help to keep them warm in the highlands. Due to warm weather in certain areas of Bolivia many Bolivians wear lightweight fabric, especially lightweight cotton. Despite the changes in civilization the many native Bolivian Indians are able to maintain their traditional style of clothing and customs. The woman wear their hair in long pigtails with a soft derby hat on their heads. Bolivian women will wear an apron over a bright skirt with many underskirts, which are cool.

Plasmodium Falciparum Life Cycle

Plasmodium Falciparum Life Cycle Malaria is one of the world leading causes of death, especially among people living in sub-Sahara Africa and other tropical regions. Of the five species of the genus Plasmodium, the malaria protozoan parasite, known to infect Man, Plasmodium falciparum is responsible for the most virulent, severe and dangerous form of human malaria. Over the years, chemotherapy has played central role in the strategies towards the eradication of this disease. However, ability of P. falciparum to develop resistance to effective and affordable drugs and to pyrathroids, the active principle of the insecticides treated nets (ITNs) has made constant search for new pharmacotherapy imperative. This review presents an overview of the life cycle of the causative organism (P. falciparum), the efforts at controlling the disease and the molecular and cellular basis of the infection, with special emphasis on molecular chaperones of the heat shock proteins family as critical components of the parasite intra-erythr ocytic development and survival. The motivation for the present work is also presented. 1.1 Introduction Malaria, whose pathogen is transmitted by female Anopheles mosquitoes, is both preventable and curable, but yet still impacting negatively on the health of millions of people and account for high rate of mortality, especially among children in sub-Sahara Africa (Breman, 2001; Greenwood et al., 2008; Hay et al., 2004; Rowe et al., 2006; Snow et al., 2005). Five species of the genus Plasmodium, the protozoan parasites, responsible for malaria infection are known to infect humans. They are P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi. It has been proposed that P. ovale consist of two species (Cox-Singh, 2010) and that zoonosis is the medium through which P. knowlesi infect humans (White, 2008). Of these, P. falciparum and P. vivax are numerically most important, with the former responsible for the most virulent, severe and dangerous form of human malaria (Greenwood et al., 2008). The World Health Organization (WHO) 2011 Malaria reports (WHO | World Malaria Report 2011, 2012) estimated a total of 216 million episodes of malaria in 2010 with at least 655 000 deaths, mostly in Africa and among children under the age of 5 years. Malaria was reported to be prevalent in 99 countries with an estimated 3.3 billion people at risk. Though, supports by international donors has led to rapid decrease in malaria mortality, especially among adults in Africa, Murray et al., (2012) contended that the malaria mortality burden may actually be larger than previously estimated and that for the necessary elimination and eradication to be achieved at larger scale, there is an urgent need for more supports. Factors, such as lack ofsanitation, malnutrition, lack or reduced access to medications, poverty and the location of many of the poor countries affected by malaria in the tropical zones, all combined together to create an enabling environment for the disease to thrive. Though pre ventive approaches such as good sanitation and distribution of insecticide treated nets (ITNs) (Curtis et al., 2006), have been employed as strategy towards the eradication of this disease, chemotherapy remains the most widely used approach. The ability of P. falciparum to develop resistance to effective and affordable drugs (Cheeseman et al., 2012; Jambou et al., 2005; Mller Hyde, 2010; Phyo et al., 2012) and to pyrethroids, the active principle of the insecticides treated nets (ITNs) (Fane et al., 2012; NGuessan et al., 2007) has made constant search for new pharmacotherapy imperative. Malaria parasite life cycle is a complex mechanism involving two hosts, human and female Anopheles mosquitoes. However, the clinical symptoms of the disease are associated with the invasion of the erythrocytes by the parasite, its growth, division inside the host cell and the cyclic cell lysis and reinvasion of new erythrocytes. The intra-erythrocytic survival and development of the parasite as well as the pathology of the infection are linked to structural and functional remodeling of the host cell through the export of parasite-encoded proteins (Botha et al., 2007; Miller et al., 2002; Pesce Blatch, 2009; Przyborski Lanzer, 2005). Meanwhile, attempts have been made to present an extensive description of the protein interaction network for P. falciparum (LaCount et al., 2005) and about 300 parasite-encoded proteins are predicted to be exported (Marti et al., 2004; Sargeant et al., 2006). Among the exported proteins are the molecular chaperones of the heat shock protein family (Nya lwidhe Lingelbach, 2006). Molecular chaperone are a family of proteins that function to stabilize proteins, facilitate their translocation across intracellular membranes, their degradation, and ensure that proteins in a cell are properly folded and functional (Hartl Hayer-Hartl, 2002; Hartl, 1996). PFA0660w belongs to an extended family of Hsp40 proteins predicted to be transported by the parasite into the host cell (Hiller et al., 2004; Marti et al., 2005; Sargeant et al., 2006). It is a Type II Hsp40 protein, said to be homologous to human DnaJB4, a cytosolic type II Hsp40, known to interact with human Hsp70 to facilitate protein folding, transport and assembly (Botha et al., 2007). Recent studies have localized PFA0660w into structures in the infected erythrocyte, called the J-dots (Kulzer et al., 2010); said to be exported in complex with P. falciparum Hsp70-x (PfHsp70-x) into the J dots (Kulzer et al., 2012) and failure to obtain a viable PFA0660w-knocked-out parasite (Maier et al., 2008), suggests that it may be essential for the survival of the parasite in the infected erythrocytes and therefore a potential target for drug action. 1.2 Malaria Infection 1.2.1 Background information Malaria, though curable and preventable, remains a life-threatening disease that was noted in more than 4,000 years ago and has being responsible for millions of death. World Health Organization (WHO) listed malaria among the most important infectious diseases of the tropics and form part of the sixth millennium development goal (MDG 6) (WHO | MDG 6: combat HIV/AIDS, malaria and other diseases, 2012). The target 6C of MDG 6 is to bring malaria and other major diseases to a halt by 2015 and begin to reverse their incidences. Strategies advocated by WHO to combat malaria includes prevention with the use of long-lasting insecticides treated bed-nets (ITNs) and indoor residual spraying, and rapid treatment with effective anti-malarial medicines with special focus on pregnant women and young children. WHO Roll Back Malaria further recommends that to control Plasmodium falciparum malaria during pregnancy, in addition to individual protection with ITNs and prompt management of anaemia and m alaria using effective anti-malaria drugs, intermittent preventive treatment (IPTp) or chemoprophylaxis should be encouraged (WHO | Malaria in pregnancy, 2012). Though, the World Health Organization (WHO) 2011 Malaria reports (WHO | World Malaria Report 2011, 2012) estimated at least 655 000 deaths as a result of malaria infection, mostly in Africa and among children under the age of 5 years, the mortality burden may actually be larger than previously estimated, thus, the need for improved supports by the funding organization to be able to achieve the much needed malaria elimination and eradication (Murray et al., 2012). Malaria is caused by the transmission of parasites to humans by female Anopheles mosquitoes during a blood meal. Plasmodium falciparum is known to be responsible for high rate of mortality, especially among children in sub-Saharan Africa, mostly under age 5 years (Breman, 2001; Greenwood et al., 2008; Hay et al., 2004; Rowe et al., 2006; Snow et al., 2005). Apart from the fact that many of the countries that are mostly affected are located in the tropical region of the world, increasing level of poverty, with its attendant economic consequences, coupled with lack of or improper sanitation and reduced access to prompt medication are factors that are creating enabling environment for the disease to thrive. Though preventive approaches such as the use of insecticide treated bed nets, IPTp and chemoprophylaxis with good sanitation (Curtis et al., 2006; WHO | Malaria in pregnancy, 2012), have been employed as strategy towards the eradication of this disease, the use of chemotherapeutic drugs remains the most widely used approach (Butler et al., 2010; DAlessandro, 2009). However, the success of this strategy has been hampered by the resilient of the parasite in continually creating resistance to the available drugs. The ability of P. falciparum to develop resistance to effective and affordable drugs (Cheeseman et al., 2012; Jambou et al., 2005; Mller Hyde, 2010; Phyo et al., 2012) and to pyrethroids, the active principle of the insecticides treated nets (ITNs) (Fane et al., 2012; NGuessan et al., 2007), has made constant search for new pharmacotherapy imperative. However, notwithstanding the centrality of chemoprophylaxis and chemotherapy in efforts at combating the menace of malaria infe ction (DAlessandro, 2009), and wide distribution of insecticide-impregnated bed nets, efforts aimed at enhancing long lasting protective immunity through vaccination, of which RTS,S is emerging as most promising vaccine formulation, have also been intensified (Ballou, 2009; Casares et al., 2010). 1.2.2 Life Cycle of Plasmodium falciparum Malaria parasite life cycle (Figure 1.1) is a complex mechanism involving two hosts, human and female Anopheles mosquitoes. The survival of the parasite during several stages of its development depends on its ability to invade and grow within multiple cell types and to evade host immune responses by using their specialized proteins (Florens et al., 2002; Greenwood et al., 2008). Sporozoites (infective stage), merozoites (erythrocytes invading stage), trophozoites (multiplying form in erythrocytes), and gametocytes (sexual stages) are stages involved in the development of the parasite. These stages are unique in shapes, structures and complementary proteins. The continuous changes in surface proteins and metabolic pathways during these stages help the parasites to survive the host immune response and create challenges for drugs and vaccines development (Florens et al., 2002). The sporogony or sexual phase occurs in mosquitoes, resulting in the development of numerous infective forms of the parasites which when ingested by human host induced disease. During a blood meal by female Anopheles mosquitoes from an individual infected with malaria, the male and female gametocytes of the parasite enter into the gut of the mosquito, adjust itself to the insect host environment and initiate the sporogonic cycle. The fusion of male and female gametes produced zygotes, which subsequently develop into actively moving ookinetes that pierced into the mosquito midgut wall to develop into oocysts. Each oocyst divides to produce numerous active haploid forms called sporozoites which are subsequently released into the mosquitos body cavity following the burst of the oocyst. The released sporozoites travel to and invade the mosquito salivary glands, from where they get injected into the human bloodstream during another blood meal, causing malaria infection (Barillas-Mury Kum ar, 2005; Ferguson Read, 2004; Hill, 2006). The parasite life cycle traverse two hosts (Man and Mosquito) with each stage involving complex cellular and molecular modifications. To prevent blood clots, Sporozoites infected saliva are deposited into Man during blood meal by female Anopheles mosquitoes, make their way to the liver, develop over time into hypnozoites (dormant stage, usually responsible for relapse of infection) or merozoites (that are released into blood stream to invade erythrocytes). The clinical symptoms of the disease are associated with the invasion of the erythrocytes by the parasite, its growth, division inside the host cell and the cyclic cell lysis and reinvasion of new erythrocytes. The schizogony or asexual phase of the life cycle occurs in human host. The cycle is initiated from the liver by the ingested sporozoites and later continues within the red blood cells, resulting in the clinical manifestations of the malaria disease. Following the introduction of invasive sporozoites into the skin after mosquito bite, they are either destroyed by macrophages, enter the lymphatics and drain into the lymph nodes from where they can develop into exoerythrocytic stages (Vaughan et al., 2008) and prime the T cells as a way of mounting protective immune response (Good Doolan, 2007) and/or blood vessel (Silvie et al., 2008b; Vaughan et al., 2008; Yamauchi et al., 2007), from where they made their way into the liver. While in the liver, sporozoites negotiate through the liver sinusoids, entered into hepatocytes, followed by multiplication and growth in parasitophorous vacuoles into schizonts, each of which contains thousands of merozoites, especially with P. falciparum (Ami no et al., 2006; Jones Good, 2006; Kebaier et al., 2009). Thrombospondin-related anonymous protein (TRAP) family and an actinmyosin motor has been show to help sporozoites in its continuous sequence of stick-and-slip motility (Baum et al., 2006; Mnter et al., 2009; Yamauchi et al., 2007) and that it growth and development within the liver cells is facilitated by the circumsporozoite protein of the parasite (Prudncio et al., 2006; Singh et al., 2007). This stick and slip motility prevent the parasite from been washed away by the circulating blood into kidney from where they can be destroyed and removed from the body. Motility is driven by an actin-myosin motor located underneath the plasma membrane. The sporozoite journey is propelled by a unique actin-myosin system, which allows extracellular migration, cell traversal and cell invasion (Kappe et al., 2004).This is a single cycle phase with no clinical symptoms, unlike the erythrocytic stage, which occurs repeatedly and characterize d with clinical manifestation. The hepatocytic merozoites are stored in vesicles called merosomes where they are protected from the phagocytotic action of Kupffer cells. The release of these merozoites into the blood stream via the lung capillaries initiates the blood stage of the infection (Silvie et al., 2008b). In some cases (as it can be found with P. vivax and P. ovale malaria) dormant sporozoites, called hypnozoites, are formed and remain in the liver for a long time. These hypnozoites are usually responsible for the development of relapse of clinical malaria infection and has been reported to be genotypically different from the infective sporozoites ingested after a mosquito bite (Cogswell, 1992; Collins, 2007). The development of the parasite within the red blood cells occur with precise cyclic accuracy with each repeated cycles producing hundreds of daughter cells that subsequently invades more red blood cells. The clinical symptoms of the disease are associated with the invasion of the erythrocytes by th e parasite, its growth, division inside the host cell and the cyclic cell lysis and reinvasion of new erythrocytes. The invasion of RBCs by the merozoites takes place within seconds and made possible by series of receptorligand interactions. The ability of the merozoites to quickly disappear from circulation into the RBCs protect its surface antigens from exposure to the host immune response (Cowman Crabb, 2006; Greenwood et al., 2008; Silvie et al., 2008b). Unlike P. Vivax, which invade the RBCs by binding to Duffy blood group, the more virulent P. falciparum possess varieties of Duffy binding-like (DBL) homologous proteins and the reticulocyte binding-like homologous proteins that allows it to recognize and bind effectively to different RBC receptors (Mayer et al., 2009; Weatherall et al., 2002). Micronemes, rhoptries, and dense granules are the specialized apical secretory organelles of the merozoite that help the merozoites to attach, invade, and establish itself in the red cel l. The successful formation of stable parasitehost cell junction is followed by entering into the cells through the erythrocyte bilayer. This entrance is made possible with the aid of the actinmyosin motor, proteins of the thrombospondin-related anonymous protein family (TRAP) and aldolase, leading to the creation of a parasitophorous vacuole, that isolate the intracellular ring parasite from the host-cell cytoplasm, thereby creating a conducive environment for its development (Bosch et al., 2007; Cowman Crabb, 2006; Haldar Mohandas, 2007). The intra-erythrocytic parasite is faced with the challenge of surviving in an environment devoid of standard biosynthetic pathways and intracellular organelles in the red cells. This challenge is overcome by the ability of the parasite to adjust its nutritional requirement to haemoglobin only, formation of a tubovesicular network, thereby expanding it surface area and by export of a range of remodeling and virulence factors into the red cell (Silvie et al., 2008b). Following the ingestion of the hemoglobin into the food vacuole, it is degraded to make available the amino acids for protein biosynthesis. Heme is a toxic free radical capable of destroying the parasite within the red blood cells. Heme polymerase is used by the parasite for the detoxification of heme and the resulting hemozoin is sequestrated as hemozoin. As the parasite grows and multiplies, new permeation pathways are created in the host cell membrane to help in the uptake of solutes from the extracellular medium, disp osal of metabolic wastes, and in initiating and sustaining electrochemical ion gradients, thereby preserving the osmotic stability of the infected red cells and thus, premature hemolysis (Kirk, 2001; Lew et al., 2003). 1.2.3 Control of Malaria infection Preventive measures are a critical step towards the control and eradication of malaria. Preventive approach can broadly be divided into two Infection control and Vector control. Infection control focuses on preventing the development of the disease as a result of occasional mosquito bite or relapse of previous infection (Lell et al., 2000; Walsh et al., 1999b). This involves the use of chemoprophylaxis. Travellers to malaria endemic countries are expected to start prophylaxis at least two weeks before and to continue up to two weeks after. One important target group in the infection control using chemoprophylaxis are the pregnant women. Intermittent preventive treatment for pregnant women (IPTp) is the globally acknowledge approach for prevention of malaria in pregnancy (Vallely et al., 2007; WHO | Malaria in pregnancy, 2012). Sulphadoxin-pyrimethamine (SP) has been used for this purpose and there are compelling arguments for the use of artesunate-SP (Jansen, 2011). To ensure long lasting prevention, this approach should be combined with vector control. Vector control focuses on protecting against mosquitoes bite, thereby preventing the transmission of the parasite to Man. Strategies for vector control include the use of residual spraying of insecticides, insect repellent cream or spray, sleeping under bed nets, especially, the insecticide impregnated bed nets (ITNs) and proper sanitation (Curtis et al., 2006; Lavialle-Defaix et al., 2011; WHO | Insecticide-treated materials,). WHO provides guideline for the production, preparation, distribution and the use of the ITNs (WHO | Insecticide-treated materials,). With the reported resistance to pyrathroids, an active principle of the insecticides treated bed nets (Fane et al., 2012; NGuessan et al., 2007), all strategies involving the use of chemical agents, also faces the global challenge of developing resistance. Training in proper sanitation and its sustainability from generation to generation is most probably the best approach in controlling the malaria disease. Personal and general hygiene which involve in-door and out-door cleaning, good refuse disposal practices, eradication of stagnant water, proper sewage disposal and clean, dry and uninterrupted drainages are examples of good sanitation practices that will not only prevent malaria infection, but also other killer diseases of the tropics. Sanitation is not only cheap and affordable; it is within the reach of everybody. 1.2.3.2 Malaria Chemotherapy Despite the use of preventive approaches outlined above (Curtis et al., 2006; WHO | Malaria in pregnancy, 2012), as strategy towards the eradication of this malaria, the use of chemotherapeutic drugs remains the most widely used approach (Butler et al., 2010; DAlessandro, 2009). They are widely employed as prophylaxis, suppressive and curative. However, the success of this strategy has been hampered by the resilient of the parasite in continually creating resistance to the available drugs. The ability of P. falciparum to develop resistance to effective and affordable drugs (Cheeseman et al., 2012; Jambou et al., 2005; Mller Hyde, 2010; Phyo et al., 2012) and to pyrethroids, the active principle of the insecticides treated nets (ITNs) (Fane et al., 2012; NGuessan et al., 2007), has made constant search for new pharmacotherapy imperative. Various approaches have been employed to identify new antimalaria agents with a view to reducing cost, ensuring availability and reducing the incidences of resistance (Rosenthal, 2003). Chemical modification of the existing antimalarial is a simple approach and required no extensive knowledge of the mechanism of drug action and the biology of the infection. Many drugs in use today have been produced using this approach, including chloroquine, primaquine and mefloquine from quinine (Stocks et al., 2001), 8-aminoquinoline, tafenoquine, from primaquine (Walsh et al., 1999a) and lumefantrine from halofantrine (van Vugt et al., 2000). Another approach is the use of plant derived compound with little or no chemical modification has led to the discovery of potent antimalarial such as artemisinins (Meshnick, 2001). Also, the use of other agents not originally designed for malaria such as folate antagonists, tetracyclines and antibiotics that were reported to be active against malaria parasit es (Clough Wilson, 2001) is another viable approach to drug discovery. Resistance reversals such verapamil, desipramine and trifluoperazine (van Schalkwyk et al., 2001) have also been used in combination with antimalaria drugs to improve therapy. Optimization of therapy with existing antimalaria agents is widely used as a productive approach towards improving therapy. Optimization of therapy underscore the need for combination therapy with newer and older drugs and with agents that are not original designed as antimalaria but which can potentiate the antimalaria property and/or block resistance to antimalaria agents. Thus for the combination to be ideal, it should improve antimalarial efficacy, providing additive or synergistic antiparasitic activity and slow the progression of parasite resistance to the antimalaria agents. For example, combination of artesunate with sulfadoxine/pyrimethamine (von Seidlein et al., 2000) or with amodiaquine (Adjuik et al., 2002), if devoid of underlying resistance to the artesunate partners which can lead to high rates recrudescence (Dorsey et al., 2002), may prove to be optimal antimalarial agents. Other combinations that have been effectively used include artesunate and mefloquine (Price et al., 1997) and artemether and lumefantrine (Lefevre et al., 2001). The combination of analog of proguanil (chlorproguanil) with dihydropteroate synthase (DHPS) inhibitor (dapsone), originally produced to treat leprosy (Mutabingwa et al., 2001) has open up a new and effective approach in antimalaria drug therapy. The use of dapsone and other drug resistance reversers such as verapamil, desipramine, trifluoperazine (van Schalkwyk et al., 2001) and Chlorpheniramine (Sowunmi et al., 1997) has shown potential for reducing the rate of drug resistance. Table 1.1: Classes and Mechanism of Antimalarial drugs CLASSES OF DRUGS Gametocidal Tafenoquine Gamatocidal Gametocidal biguanides (proguanil, cycloguanil), Trimethoprim CLASSES OF DRUGS Clindamycin, Spiramycin m ubiquinol to cytochrome C (Vaidya, 2001). Meanwhile, one important and innovative approach towards drug discovery in malaria chemotherapy is the search for new antimalaria drug target. Such targets include parasite membrane (Vial Calas, 2001), food vacuole (Banerjee et al., 2002), mitochondrial and apicoplast (Ralph et al., 2001; Vaidya, 2001). The cytosol, which is the centre of metabolic activities (e.g. folate metabolism and glycolysis) and enzymes activities have proven to be valuable as potential target for drug action (Plowe, 2001; Razakantoanina et al., 2000). To survive and develop within the erythrocytes, Plasmodium falciparum export most of its virulent factors into the cytosol of the infected erythrocytes. Among these are the molecular chaperones of the heat shock proteins which are focus of many researches and are increasingly gaining ground as potential target of drug action (Behr et al., 1992; Kumar et al., 1990). 1.2.3.3 Malaria Vaccines Notwithstanding the centrality of chemoprophylaxis and chemotherapy in efforts at combating the menace of malaria infection (DAlessandro, 2009), and wide distribution of insecticide-impregnated bed nets, efforts aimed at enhancing long lasting protective immunity through vaccination, of which RTS,S is emerging as most promising vaccine formulation, has been intensified (Ballou, 2009; Casares et al., 2010). These attempts at producing an effective vaccine against malaria infection has, however, for many years proved unsuccessful (Andr, 2003; Artavanis-Tsakonas et al., 2003). Having a vaccine that can completely block transmission from human to mosquito host can be a major limp towards global eradication of malaria. But, the absences of such immunity may explain the possible partnership between the parasite and the host, developed over a long time of co-habitation (Evans Wellems, 2002). On the other hand, a vaccine developed in line with the model of naturally acquired immunity that o ffers protections against morbidity and mortality, offers more encouragement. Such a vaccine will be a major step in the right direction and may not require regular booster vaccination like it would with vaccine that target infection transmission blockage (Struik Riley, 2004). Meanwhile, the development of natural immunity, after a long term exposure to the infection, especially with people living in the endemic areas has been reported (Baird, 1995; Hoffman et al., 1987; Rogier et al., 1996). The rate of acquired immunity in infants is faster than older children, but they also stand the chance of higher risk of developing severe malaria infection and anaemia (Aponte et al., 2007). Though, adults who, having obtained naturally acquired immunity, migrated to malaria-free zones, stands the risk of contacting the diseases upon return to their endemic region, documentary evidences however revealed that their responses to such re-infection are very rapid and tend to respond to treatment and recover faster than those who have not been previously xposed. (Di Perri G et al., 1994; Jelinek et al., 2002; Lepers et al., 1988). While this naturally acquired immunity is beneficial, it leaves the most vulnerable population (children and pregnant women though the mother may be immune, the foetus is not) at risk, as they are yet to gain enough exposure for such immunity to take place. Aponte et al., (2007) also showed that a reduced exposure toP. falciparumantigens through chemoprophylaxis early in life have the potential to delay immunity acquisition. Furthermore, it does not appear that naturally acquired immunity have any effect on transmission of malaria. This further explained the possibility of an evolving host-parasite relationship (Evans Wellems, 2002), which might have been developed over a long time host-parasite co-evolution. Therefore, understanding the compromises that may have developed over time between the parasite and the host may be an important approach towards developing a much needed vaccine. 1.3 Molecular and Cellular Basis of Malaria Infection Following blood meal by an Anopheles female mosquito accompany with the release of saliva to prevent blood coagulation (Beier, 1998), malaria parasites are deposited or ejection of into the skin (Frischknecht et al., 2004; Vanderberg Frevert, 2004). By continuous gliding in the skin, the sporozoite reach a blood vessel, breach the endothelial barrier and enter the blood circulation (Amino et al., 2007; Vanderberg Frevert, 2004) and/or breach a lymphatic vessel to enter the draining lymph node, where exoerythrocytic stages of sporozoites development may take place (Amino et al., 2006). A micronemal protein, called thrombospondin-related anonymous protein (TRAP), has been shown to be responsible for the gliding motility and invasion mosquito vector salivary gland and in mammalian host (Kappe et al., 1999). The sporozoite transversal to the liver and the merozoites invasion and remodeling of the host cells are complex but necessary processes for the survival and development of the par asite. 1.3.1 Cell Transversal Sporozoite possesses the ability to transverse cells i.e move in and out of the host cells by membrane disruption (Mota et al., 2002, 2001; Vanderberg Stewart, 1990). Among the proteins secreted by the micronemes that have been implicated in host cell traversal are SPECT1 (sporozoite microneme proteinessential forcelltraversal 1) and SPECT2 (Ishino et al., 2005, 2004). The absence of SPECT1orSPECT2in mutant sporozoite does not prevent gliding motility but prevent migration through host cells (Ishino et al., 2004).Other proteins of importance to sporozoite cell traversal prior to hepatocyte infection, includes TRAP-Like Protein (Moreira et al., 2008), a sporozoite secreted phospholipase (Bhanot et al., 2005), and celltraversal protein forookinete andsporozoite (Kariu et al., 2006). Similarly, the circumsporozoite protein (CSP) probably plays a role in targeting sporozoites to hepatocytes by interacting with heparin sulfate proteoglycans (Sinnis Sim, 1997). 1.3.2 Liver stage development Upon entering the bloodstream, infectious sporozoite makes it way to the liver. Circumsporozoite protein (CSP) is highly expressed at this stage of the parasite life cycle. Using the sporozoites that expresses fluorescent proteins under the control of CSP and intravital imaging, Frevert and colleagues were able to show the movement of sporozoites in the liver (Frevert et al., 2005). The study showed that sporozoite migrates through several hepatocytes before finally settling in one, form PV and begin the liver stage development. CSP, mediated by low-density lipoprotein receptor-related protein LRP-1, and other highly expressed proteins by Kupffer cells, play an important role in inhibiting the generation of reactive oxygen species via the generation of cyclic AMP (cAMP) which stimulates adenyl cyclase activity (Usynin et al., 2007). Ishino and co-workers reported that two parasite molecules P36 and P52/P36p are involved in sporozoite invasion of hepatocytes with the formation of a PV membrane (PVM) (Ishino et al., 2005). Apart from CSP, other gene product that has been implicated in liver stage development of the parasite includes sporozoite low complexity asparagine-rich protein (SAP1) (Aly et al., 2008) and sporozoite and liver stage asparagine-rich protein (SLARP) (Silvie et al., 2008a) 1.3.3 Erythrocyte Invasion Erythrocyte invasion involves four steps, namely, initial merozoites binding, reorientation and erythrocyte deformation, specific interaction and junction formation and parasite entry (Figure 1.2). Merozoite surface protein-1 (MSP-1) is a well characterized merozoite surface proteins implicated in initial merozoite binding. It has been reported to be uniformly distributed over the merozo