Stash
Ekagra Agarwal's Stashed Knowledge
Ravens
A woman from New Orleans who read the article on ravens that I wrote when I had just started to investigate whether and how ravens share, wrote me: "I did not have so much trouble as you did in showing that ravens share. I see them at my feeder - they even feed one another". There are no ravens in New Orleans, nor anywhere else in Louisiana. Perhaps what she actually saw were several large dark birds (crows? Grackles?), one of which fed another one or two (probably their grown offspring traveling along with them). People commonly confuse personal interpretations with factual observations. This tendency is a special bane in getting reliable observations on ravens because so much ingrained folklore about them exists that it is difficult to look at them objectively. I once read an article about a trapper/writer in Alaska. Knowing he would be familiar with ravens in the north, I wrote to ask him if he had seen ravens feeding in crowds. He had a lot of raven stories to tell. First, he said "everyone" he knew, knew that ravens share their food. He was surprised at the ignorance of us armchair scientists so far away, who would even question it. Ravens were "clever enough" to raid the fish he kept on racks for his dogs. They proved their cleverness by posting a "twenty-four-hour guard" at his cabin. (How did he distinguish this, I wondered, from birds waiting for an opportunity to feed?) As soon as he left the cabin, a raven was there to "spread the word". (Read: Flew away and/or called.) He claimed that one raven "followed" him all day. (Read: He occasionally saw a raven.) It then "reported back" to the others so that they could all leave just before he got back from his day on the trapline. (Read: He saw several leave together, and there were none when he got back to the cabin door.) Many of the birds "raided" (fed from?) his fish rack, and his idea of their "getting out the word" to ravens for miles around is that the one who discovers the food calls, and thereby summons all the birds in neighboring territories, who then also call in an ever-enlarging ring of information sharing. (An interesting thought).) It was no mystery to him why the birds would do this: they are "gossiping". "It seems obvious", he said, "that the birds get excited, and they simply cannot hold in their excitement - that lets others know". Any why should they evolve such transparent excitement? That, too, was "obvious": "Because it is best for the species". This stock answer explains nothing. It was disturbing to me to see anyone so facilely blur the distinction between the observations and interpretations and then even go so far as to make numerous deductions without the slightest shred of evidence. When I was very young and did not "see" what seemed obvious to adults, I often though I was stupid and unsuited for science. Now I sometimes wonder if that is why I make progress. I see the ability to invent interconnections as no advantage whatsoever where the discovery of truth is the objective. There are those who believe that science consists entirely of disproving alternative hypotheses, as if when you eliminate the alternative views, the one you have left is right. The problem is that there is no way to think of all the possible hypotheses that nature can devise. More than that, you have to prove which is the most reasonable. But any one hypothesis can, with a limited data set, be reasonable. There is at least a touch of truth in the idea that any variable affects another. If you look long and determinedly enough you will find that almost any variable element you choose to examine apparently affects the behavior you are studying. You have to be able to skim over what is not important or relevant to your problem, and to concentrate long enough on the prime movers to unearth sufficient facts that, presuming they are recognized, add up to something. Q. 6.
Sparsha Saha
The shifting of world powers
As we enter 2008, the countdown is well under way for August's Olympic Games in China. Yet, months before the Olympic torch sparks into life in Beijing, China and its fellow Asian nations have already raced into a position of global leadership. This year, emerging-market nations, led by Asia, will overtake the rich countries of the developed world to become the most important collective engine for global growth. As the mighty US economy falters and once-so-superior Europe stumbles, China, for the first time since the early 19th century, will become the largest national contributor to world economic expansion. That will be true whether China's impact is calculated by measuring what it produces at market values, or after making adjustments so that a dollar would buy the same goods if it was spent in Beijing or New York. This historic - presumably temporary - passing of the baton of global economic leadership from the West to the emerging powers of Asia is a moment as remarkable as the breaking of the four-minute mile. However, as Western governments confront the industrial world's diminishing prospects in what will be their most testing year since the start of the century, the passing of this milestone has left markets fretting over two crucial questions. First, can these emerging markets really sustain their outperformance, charging ahead at the front of the field even as the big economic powers of the Group of Seven developed countries fall behind? Secondly, will their stamina help to sustain the West's failing performance? The good news is that the odds look very much in favour of Asia and emerging markets sustaining their strong performance this year despite the G7's plight, a phenomenon that economists have dubbed "decoupling". The bad news is that while this trend will help to bolster global growth, its benefits to the industrialised world will be limited and are likely to come at a significant cost, both literally and metaphorically. Scepticism over the decoupling idea remains pervasive among financial markets as well as policymakers. The old dogma that if America sneezes the rest of the global economy must inevitably catch a nasty chill remains a deeply rooted piece of conventional wisdom - understandably so, since investors or governments dismiss the potency of the US economy as a driving force at their peril. Yet the reality is that this familiar prognosis of inescapable global contagion from America's ills is almost certainly misplaced. Crucially, the exposure of Asia and other emerging markets to this US downturn is vastly less than their vulnerability to the fallout triggered by the dot-com bust of 2000. In the previous US downswing, there was no escape for emerging markets. The huge bubble in internet and technology-related shares was not only an American but also a worldwide trend. When Wall Street fell, stock markets across the world, including those in emerging markets, were, unavoidably, hit. The impact of the financial toll on Asia was then magnified since the region's factories were the world's workshop for huge quantities of the high-tech gear for which demand abruptly slumped. This time round, things are drastically different. The origins of US economic woes lie in its residential housing market, a sector that has its impact almost wholly within America's borders. As Merrill Lynch puts it: "The world does not build American houses."
pallavi gawas
DNA-THE CENTRAL DOGMA
he start of a distinct modern molecular biology dates from the discovery of the structure of DNA by Watson and Crick. In his book, The Double Helix, Jim Watson writes: "Back" in my rooms I lit the coal fire, knowing there was no chance that the sight of my breath would disappear before I was ready for bed. With my fingers too cold to write legibly I huddled next to the fireplace, daydreaming about how several DNA chains could fold together in a pretty and hopefully scientific way. Soon, however, I abandoned thinking at the molecular level and turned to the much easier job of reading biochemical papers on the interrelations of DNA, RNA and protein synthesis. Virtually all the evidence then available made me believe that DNA was the template upon which RNA chains were made. In turn, RNA chains were the likely candidates for the templates for protein synthesis. There was some fuzzy data using sea urchins, interpreted as a transformation of DNA into RNA, but I preferred to trust other experiments showing that DNA molecules, once synthesized, are very stable. The idea of the genes' being immortal smelled right, and so on the wall above my desk I taped up a paper sheet saying DNA -> RNA -> protein. The arrows did not signify chemical transformations, but instead expressed the transfer of genetic information from the sequences of nucleotides in DNA molecules to the sequences of amino acids in proteins" The term Central Dogma is ascribed to Frances Crick. In his book, What Mad Pursuit, he describes why he used this term: "The other theoretical idea I proposed was of a rather different character. I suggested that "once 'information' has passed into protein it cannot get out again," adding that "Information means here the precise determination of sequence, either of bases in the nucleic acid or of amino acid residues in the protein. I called this idea the central dogma, for two reasons, I suspect. I had already used the obvious word hypothesis in the sequence hypothesis, and in addition I wanted to suggest that this new assumption was more central and more powerful. I did remark that their speculative nature was emphasized by their names." Nearly 20 years ago, biochemists found that a separable constituent of the cell Deoxyribonucleic acid or DNA appeared to guide the cell's protein synthesizing machinery. The internal structure of DNA seemed to represent a set of coded instructions which dictated the pattern of protein synthesis. Experiments indicated that in the presence of appropriate enzymes each DNA molecule could form a replica, a new DNA molecule containing the specific guiding message present in the original. This idea when added to what was already known about the cellular mechanisms of heredity appeared to establish a molecular basis for inheritance. Proponents of the theory that DNA was a self duplicating molecule, containing a code that by itself determined biological inheritance, introduced the term 'central dogma' into scientific literature in order to describe the principles that were supposed to explain that the reverse effect is impossible, proteins cannot guide the synthesis of nucleic acids. But actual experimental observations deny the second and crucial part of this assumption. Other test-tube experiments show that agents besides DNA have a guiding influence. The kind of protein made may depend on the specific organism from which the necessary enzyme is obtained. It also depends on the test tube's temperature, the degree of acids and the amount of metallic salts present. The central dogma banishes from consideration the interactions among the numerous molecular processes that have been discovered in cells or in their extracted fluids. In the living cell, molecular processes - the synthesis of nucleic acids and proteins or the oxidation of food substances - are not separate but interact in exceedingly complex ways. No matter how many ingredients the biochemists test tubes may contain the mixtures are nonliving; but these same ingredients organized by the subtle structure of the cell constitute a system which is alive.
apeksha rajkumari
CONNECTING ROD
A standard connecting rod used in automobiles
ayushman dutta
3D PRINTING OF UNIVERSAL JOINT: AN ACADEMIC PROJEC
3D PRINTING OF UNIVERSAL JOINT: AN ACADEMIC PROJECT A universal coupling/joint is used to facilitate rotation between shafts which are inclined to each other. The angle between the two shafts is called the operating angle. It Is generally, but not necessarily, constant during operation. In order to achieve perfect rotation, 2 joints are generally used with an intermediate shaft in between. The method used in making this joint was FDM 3D PRINTING. It is a rapid manufacturing method which can quickly make intricate and complex shapes which are otherwise, very cumbersome in case of conventional machining processes. 3D printing is used to manufacture the universal coupling as our project. The 3D printing machine used here is a FDM 3D PRINTING machine which uses ABS material. Considering the volume (in cc) of our entire assembly, the total cost (including taxes and cost of support material) was Rs. 811. The total time taken for the 3d printing process was approximately 5-6 hours, excluding the time taken to manually remove the support material stuck on the finished surfaces. The general procedure for the 3d printing of the universal joint involved the following steps: We used the Solidworks model of a universal joint and scaled down its overall dimensions. The dimensions were reduced proportionally in a manner such that the distance between the 2 extreme ends of the assembly does not exceed 5 cm. The design of the individual components and the overall assembly was submitted to the labin- charge of the 3d printing machine. The models were converted to .stl files and their net volume (in cc) and weight was calculated (for cost purposes). The machine calculated an estimate of 5-6 hours for the entire process. After the printing was done, we used sharp pins and needles to remove the support materials. Since it is a relatively small model, the support material were stuck and had to be removed, especially from the holes. Using drilling, the hole of the fork component was enlarged to properly insert the collar pin and assembling the other components. The miniature universal joint can be used to rotate small shafts which are not properly oriented to each other. It can also be used to support rotation between shafts which are parallel but not in the same level. This can be achieved by used 2 universal joints. Being made of ABS, there are lesser chances of rusting and chemical degradation by acids and abrasive chemicals. The total manufacture time required for the joint was 5-6 hours. For a universal joint of the size mentioned here, it would take much more time if conventional machining processes were used. The method can be easily used as an alternative to machining processes.
DESIGN METHODOLOGY OF A SPRING LOADED RELIEF VALVE
DESIGN METHODOLOGY OF A SPRING LOADED RELIEF VALVE INTRODUCTION: In this CASE STUDY, a spring loaded safety relief valve has been designed based on a given problem statement. The design procedure involves the following: Designing of the SPRING to be used Designing of the THREADED FASTENER to be used for joint The spring loaded safety valve has been assumed to be an assembly consisting of a spring (to be designed). The assembly attached to a pipe joint using a flange. Based on the cracking pressure, the shape of the flange and the resulting no. of threaded fasteners have to be decided. Having decided the nature of the flange the dimensions of threaded joints must be decided. PROBLEM STATEMENT: A boiler safety relief valve, using a close coil helical spring is set to blow-off at a fluid pressure of 0.35 N/mm2. A suitable compression spring is required for the purpose. The valve diameter is 12.70 mm. Use a suitable spring constant. Maximum lift allowed is 5 mm and the initial compression in the spring is 10 mm. Maximum shear stress allowed for wire is limited as per the material of the wire. Find the necessary dimensions of the spring. The given valve is vertically attached to the top of a boiler with the help of a flange coupling using a certain number of bolts. Based on the working stress being subjected to the coupling, determine the bolt dimensions required for keeping the valve seated. GIVEN DATA AND ASSUMPTIONS MADE: Depending on the application (steam boiler), the following data has been gathered: Material selected= Carbon steel C= 6 τ= 294 MPa G= 80 kN/mm2 Max. pressure= 0.35 N/mm2 Valve dia=12.70 mm Bolt material= ASTM A36 (σt= 450 MPa) F.O.S =8 CALCULATION FOR SPRING: Given in attachment.
The sceptic media
Every day, experts bombard us with their views on topics as varied as Iraqi insurgents, Bolivian coca growers, European central bankers, and North Korea's Politburo. But how much credibility should we attach to the opinions of experts? Skeptics, warn that the mass media dictate the voices we hear and are less interested in reasoned debate than in catering to popular prejudices. As a result, fame could be negatively, not positively, correlated with long-run accuracy. Until recently, no one knew who is right, because no one was keeping score. But the results of a 20-year research project now suggest that the skeptics are closer to the truth. I describe the project in detail in my book Expert Political Judgment: How good is it? How can we know? The basic idea was to solicit thousands of predictions from hundreds of experts about the fates of dozens of countries, and then score the predictions for accuracy. We find that the media not only fail to weed out bad ideas, but that they often favor bad ideas, especially when the truth is too messy to be packaged neatly. The evidence falls into two categories. First, as the skeptics warned, when hordes of pundits are jostling for the limelight, many are tempted to claim that they know more than they do. Boom and doom pundits are the most reliable over-claimers. Between 1985 and 2005, boomsters made 10-year forecasts that exaggerated the chances of big positive changes in both financial markets. They assigned probabilities of 65% to rosy scenarios that materialized only 15% of the time. In the same period, doomsters performed even more poorly, exaggerating the chances of negative changes in all the same places where boomsters accentuated the positive. They assigned probabilities of 70% to bleak scenarios that materialized only 12% of the time. Second, again as the skeptics warned, over-claimers rarely pay penalties for being wrong. Indeed, the media shower lavish attention on over-claimers while neglecting their humbler colleagues. We can see this process in sharp relief when, following the philosopher Sir Isaiah Berlin, we classify experts as "hedgehogs" or "foxes." Hedgehogs are big-idea thinkers in love with grand theories: libertarianism, Marxism, environmentalism, etc. Their self-confidence can be infectious. They know how to stoke momentum in an argument by multiplying reasons why they are right and others are wrong. That wins them media acclaim. But they don't know when to slam the mental brakes by making concessions to other points of view. They take their theories too seriously. The result: hedgehogs make more mistakes, but they pile up more hits on Google. Imagine your job as a media executive depends on expanding your viewing audience. Whom would you pick: an expert who balances conflicting arguments and concludes that the likeliest outcome is more of the same, or an expert who gets viewers on the edge of their seats over radical Islamists seizing control and causing oil prices to soar? At this point, uncharitable skeptics chortle that we get the media we deserve. But that is unfair. No society has yet created a widely trusted method for keeping score on the punditocracy. Even citizens who prize accuracy have little way of knowing that they are sacrificing it when they switch channels from boring foxes to charismatic hedgehogs. Here, then, is a modest proposal that applies to all democracies: the marketplace of ideas works better if it is easier for citizens to see the trade-offs between accuracy and entertainment, or between accuracy and party loyalty. Wouldn't they be more likely to read pundits with better track records?
kevin dudeja
News media buisness
News media businesses can no longer rely solely on making money from traditional advertising and must embrace the multiple commercial opportunities from online, according to magazine publisher and broadcaster Andrew Neil. The Press Holdings chairman, BBC presenter and former Sunday Times editor said the changes sweeping the media industry were "transformative and revolutionary" and that traditional ways of making money had all but eroded as increased competition and the explosion of online media erodes the exclusivity of advertising deals. Speaking at today's SIIA Global Information Industry Summit in London, Neil said that the internet was not a threat to the traditional printed media companies, but an "essential" opportunity to diversify and ultimately save them. "Sensible newspaper and magazine publishers do not see online as a threat or something they have to do because 'it is the future, so let's do it and grit our teeth'," he said. "Offline publications are still necessary for brand building and because people still like to hold a newspaper or particularly a magazine. But the revenues for that are in decline as search engines make classified ads increasingly irrelevant." Neil pointed out that his magazine websites (- he is also chairman of ITP Publishing, the Gulf's largest magazine publishers) were visited mainly by people who also read the print version and visit the site "for the additional material that is only online". He said The Spectator, owned by Press Holdings, had achieved great success with its Coffee House network of blogs, which has 200,000 unique users a month and will contribute "20 per cent of the bottom line" this year in terms of revenue. He also pointed out that the one of the biggest spikes in traffic for Telegraph.co.uk was around 10am every day, when the print readers had finished their Daily Telegraph and wanted to know what else its journalists were doing. "You now need to use online to do a whole host of things that you just could not before," he added. "It ceases to be an either-or situation." Neil admitted the going was tough for the media in a multi-platform world with complex revenue streams but it was, for him at least, "a lot more fun". He contrasted the UK market with the US, in which newspapers are run by big city monopolies that are unused to competition and "run for the journalists and not for the readers". In the UK many mainstream publishers grasped the need to diversify early on: "Most trends like this begin in the US but in this trend the British media are particularly much ahead of them," he said. "British newspapers have always been used to competition: it's the most competitive newspaper market in the world bar none."
Abhisekh Deshmukh
Money laundering and Migration
The amount of money sent back home by migrants working abroad has grown rapidly in recent years -according to the World Bank it doubled in the five years from 2002, reaching at least $350bn. But the mechanisms used to transfer money can also be used for money laundering, and are of increasing concern to law enforcement agencies. Some estimates suggest that half of all money transfers from migrants living abroad are done outside the formal sector - that is, banks or money transfer firms. Of course, most migrant transfers are for legitimate reasons. But the vast volume of informal transfers has made it much easier to hide illicit transfers, whether they relate to criminal activity or terrorist finance. There are two reasons for the growth of the this informal sector. The first is the expense of transferring money abroad for poor individuals. The cost, especially for small amounts sent to nations with a less well-developed financial sector, can be as much as 20% of the sum, according to the World Bank. Secondly, there are a number of countries, for example in parts of Africa and the Middle East, where the banking system is not highly developed and so cash transactions are common. As directly sending cash, or its equivalent in gold or diamonds, is potentially risky, this has led to the widespread use, in Muslim countries, of the hawala system. Hawala is an informal system of money transfer based on trust, which uses a system of money brokers based throughout the Middle East, Africa and Asia, with links to others in major cities across Europe and North America. Under hawala, no money actually crosses international borders. Instead, a system of complex swaps is employed, using food, fuel, electronics or gold as a way of balancing the books between operators - hawaladas - in different countries. The OECD's Financial Action Task Force says these "alternative remittance systems" are widely used by terrorist finance, because of the "level of anonymity and rapidity" they offer, and for "cultural" reasons. They say that they have the additional attraction of "weaker and/or less opaque record-keeping" and in many places "less stringent regulatory oversight". This might particularly apply in failed states, such as Somalia, or large parts of Afghanistan. Finding terrorist funding in the huge volume of international money transfers may seem akin to looking for a needle in a haystack. The volume of normal transactions dwarfs the amount of money needed to carry out terrorist actions. The OECD estimates that the direct operational costs of major terrorist actions like the London and Madrid bombings were no more than $10,000 to $12,000 (£6,751 to £8,100). This level of funding - or even the Bali bombing, estimated to have cost $50,000 - could easily be incorporated into the hawala system. But the OECD says terrorist networks need other longer term funding to support their operations and logistics base - and so will also turn to money laundering, criminal activities, and the use of charities as conduits for money. Regulators, particularly in Europe, are beginning to tighten up the supervision of all types of financial institutions, formal and informal. An EU directive comes into force in 2009 that will compel financial companies above a certain size to become registered with the FSA and to put up bonds proportionate to their turnover or profit. At the same time, The World Bank has been pushing to lower the cost of formal money transfers. One possibility is to make more use of the postal system, which has the ability to create a global money transfer system. Another new development could be the use of mobile phone systems to credit small amounts to users. This would be particularly attractive in developing countries, where mobile phone use is growing and is much more dense than internet use. Meanwhile, private agencies such as Western Union and Moneygram have expanded rapidly across the globe, and the money transfer business has proved highly profitable, growing by 6% per year. There is no doubt that, overall, remittances make a positive contribution to economic growth in poor countries - although they might be better targeted. So finding ways of improving transfers, while avoiding the risks of hiding money, could be useful for economic development. And improving living conditions in these countries could be in itself an important antidote to the appeal of anti-Western militancy across the globe.
sagar sinha