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[转帖]GMAT阅读背景文章
再次感谢iamf！！我来贴一些以前的背景文章吧。[em23]
found one article:企业价值观(explicit value /hidden value)对决策者的影响。
阅读次数：672
shushu 2002-08-29 13:55:12
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Management extracts hidden corporate value at
GE, Dow, and Hughes Space and Communications
Two hundred years after Adam Smith recognized the potential role of manufacturing in industrial society, we have entered an era in which the wealth of nations depends on the creation, transformation, and capitalization of knowledge. Corporate knowledge has become a leading competitive factor—knowledge wrapped up in intellectual assets/intellectual property such as information, patents, trademarks, and copyrights and knowledge wrapped up in corporate management systems, customers, and human resources. But traditional models of accounting and management have often been criticized as not being sufficient to measure and report the current and potential value of companies whose primary assets fall into these categories.
A new management paradigm has emerged over the past five years that attempts to address this problem called intellectual capital management or ICM. ICM builds a new framework for thinking about what constitutes value in a company—a new framework for growing, extracting, and measuring corporate value that doesn’t necessarily rely on revenue flows or tangible assets as a basis for accounting.
Intellectual capital is a term/concept that applies to the missing value between book value and market value of the firm. This “missing value” can represent up to 75% of the market price of the company vis-?vis its hard assets. This phenomenon is due to the increasing role of knowledge (both tacit and explicit) in creating shareholder value and a broad recognition that corporate knowledge is power in industry, particularly when it comes to competing on the basis of speed to market. (Tacit knowledge is the experience and intellectual creativity and learning that rests with the human resources of the firm. Explicit knowledge is knowledge that can be codified into information and accessed and disseminated systematically.)
Three large U.S. companies, Hughes Space and Communications (HSC), Dow Chemical, and General Electric, are focusing on managing, measuring, and reporting the intellectual capital and, as a result, benefiting from this relatively new approach to thinking about corporate value.
HSC: The Cost Efficiencies of Knowledge
“Unlike many companies, our knowledge management program is not a stand-alone thing and doesn’t have its own objectives—it only exists to support our strategic direction, and it’s focused on that,” says Arian Ward, former leader of Collaboration, Knowledge, and Learning, HSC.
Hughes Space and Communications, a subsidiary of Hughes Electronics, is the world’s largest producer of commercial communications satellites. Over the last five years one of the key competitive factors at HSC has been its ability to bring technological innovation to market while reducing design and development costs to a level that would allow it to expand its customer base. How does Hughes do it? By managing its intellectual capital.
A key challenge at HSC, for example, was to reengineer the design process to capture the tacit and explicit knowledge that had been previously hidden in knowledge silos. As HSC is a science and technology contract environment, this used to mean nonstandardized products and a high degree of specialization in product development and design. “Islands of knowledge” or knowledge silos had emerged within departments, programs, and customer groups. This condition created unnecessary repetition in product development, longer than necessary cycle times, and higher associated costs. HSC addressed the problems created by these islands of knowledge by dramatically reengineering its satellite development and design process into what it called the Integrated Satellite Factory. The Integrated Satellite Factory was built around Communities of Practice (CoPs)—an informal work group that shares a common purpose and a common set of practices, usually members of a specific profession or specialty who often work in different processes, departments, or functions.
Prior to developing the CoPs strategy, these work groups worked autonomously with different work practices, systems, and standards. By developing CoPs, HSC enabled business units, projects, and functions to share practices, standards, and sometimes people. HSC supports the CoPs by promoting knowledge-sharing processes such as collaborative conversations, providing collaborative technologies such as groupware and desktop video conferencing, and developing new support roles such as knowledge stewards, CoP facilitators, and boundary spanners.
The development of CoPs has improved the exchange of information at Hughes and has facilitated establishing an inventory of best practices. By utilizing best practice information and removing communication barriers that existed between groups, HSC eliminated some of the repetition involved in proj- ect development and design and thereby reduced costs and cycle times. As a result, customers that were once excluded from purchasing satellites due to high telecommunications market entry costs and long payback periods are now able to seek HSC solutions.
According to Arian Ward, “What was happening at HSC was that each program (satellite) was tailored to the specific customer. There was a lot of repetition of process and design that created cost and cycle time inefficiencies. By establishing mechanisms such as the CoPs and our intranet capabilities, we could eliminate some of the repetition. This, in turn, enabled us to reduce our costs and cycle times and, therefore, to offer satellite technology to a new class of customers that previously was unattainable to them due to high market entry costs and long payback periods.”
Dow: the Innovation Revolution
At Dow Chemical there’s a distinct relationship among the innovative capabilities of the organization, its ability to compete on the basis of productivity, and, ultimately, its prospect for long-run profitability. Fernand Kaufman, senior VP, New Business, noted that innovation helps achieve superior productivity and cost competitiveness. To him, “An innovative organization is the cornerstone of growth and profitability.”
The main mechanism for directing and monitoring Dow’s growth is the CEO Growth Forum. The Forum is made up of the seven most senior people in the company—the executive committee, the manufacturing VP, the R&D VP, and the VP, New Business. Members of the Forum support prototypes and new business models and explore potential vertical integration options and other initiatives focused on growth. They focus on growth opportunities that tend to be outside the normal operations of the company. These business opportunities may include totally new business models or products and processes that sit across two or three different lines of business (such as a foray into an automotive market that Dow serves from many different business units).
Dow has made extensive use of several organizational assessment tools to help guide its growth strategies. One such tool was the Staircase for Growth Model that essentially provided direction for expanding organizational competencies, technological capabilities, and customer reach over time.
Cost and Process Improvements
Since 1992, Dow Chemical has largely focused on improving productivity through process innovations and significant cost reductions. Dow set aggressive targets of achieving a 50% reduction in conversion costs; nonmaterials-related production costs; and achieving more stringent health, safety, and environmental targets than ever before including a 90% reduction in all emissions. Historically, Dow has been slower in bringing products to market than its competitors. In order to address this problem, it reengineered processes; eliminated layers of bureaucracy; and invested in communications, training, and education tools that would help eliminate knowledge silos.
For example, the Leadership Development Network is a company-wide two-day training session that the company has developed within the last five years in which 3,000 middle managers take instruction on new corporate programs/strategies and then communicate them to the rest of the organization. The program is a top-down initiative taught by 50 of Dow’s most senior level managers who themselves have attended a two-day session conducted by the CEO or other members of the executive office.
Customer Insight Tools and Management
According to Kaufman, because organizations are typically internally focused, investing in customer insight tools such as data warehouses and developing more formal processes for scanning the environment are critical to marketing, financial management, and corporate growth. Dow recently has made significant investments in information technology that integrates customer-based information with the organization’s financial accounting systems and its value-Based Management system. This system has enabled them to segment their markets in detail, giving them access to profitability figures by customer and providing them with information on customer value gain by product.
One of the main challenges, according to Kaufman, in managing customer information is to build a knowledge management system that can provide information in a codified, organized way yet allows it to be tracked back to the source. Dow also maintains an elaborate customer technical service system. Via a call center, technical problems get routed to an automated solution or to a company expert. Over the last three years this system has resulted in a cost saving of 30% on R&D costs. Finally, it has created a business intelligence group to scan the environment, to observe or predict changes in the applications of their products, to learn about the trends in the technologies surrounding these applications, and to understand where the market is headed.
GE: Best Practices in Organizational Learning
Prior to the installation of new CEO Jack Welch in 1981, GE was considered a very insular company. Today, GE has exhaustive processes for identifying best practices from outside the organization because of one of Welch’s legacies. For example, at the GE training center every class is challenged to go into companies around the world to uncover best practices and apply them to GE. According to Kerr, “We’re always creating these mechanisms and processes to remove barriers, transfer knowledge, and help people utilize knowledge.” His job, as chief learning officer, is to facilitate the move toward this “boundary-less organization” by communicating and integrating best practices within GE.
GE competes on its ability to meet changing market conditions quickly. Steve Kerr notes, “This involves a very multidimensional set of objectives, goals, tactics, tools, and methods that are geared toward making GE better at predicting and responding to markets.” In order to provide greater value to customers while minimizing the company’s exposure to risk, GE has become a prolific producer of customer information. In addition to customer insight tools such as surveys, focus groups, and interviews, many formal mechanisms have been implemented to enable GE to respond to individual customer demands as well as changing market conditions. GE also is committed to total quality management systems such as Six Sigma and has created corporate performance systems such as Dashboards and Scorecards for each of its major clients to ensure that quality and service are maintained.
Breaking ‘Knowledge Silos'
Clearly, corporations like Hughes, Dow Chemical, and GE have taken the management of knowledge, information, and corporate intelligence seriously. By developing communities of practice (CoPs), Hughes has integrated a potentially broad, and previously untapped, range of knowledge that rested within departments, customer groups, and human resource designations. The resulting cost efficiencies from improving the design flow has facilitated speed to market and opened up opportunities for developing new clients. At Dow Chemical, the CEO Growth Forum takes new venture propositions and assesses the potential to leverage them across the organization. Meanwhile, its Business Intelligence Group closely monitors changes in the customer, technology, market, and regulatory environment.
Corporate knowledge is further leveraged through elaborate information systems that codify explicit knowledge of customers. Ensuring that the knowledge source is identifiable and traceable continues to be one of the major challenges in building a knowledge management system. At GE, implementing best practices company-wide has been a primary knowledge management strategy. As in Hughes Space and Communications, organizational learning at GE has increased speed to market and helped to break down the traditional “knowledge silos” that plague large corporations.
找到一篇关于Episodic Memory的摘要
阅读次数：503
angel 2002-08-29 13:31:42
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刚刚找到一篇关于Episodic Memory（片断记忆）的摘要，尽管很短，由于该题是高频考题，所以特此刊出，至少可以从中领会一下这一概念。
另外以往的机经很多都把该词误写为epidemic memory，在此特别更正，应该是Episodic Memory（片断记忆），以免被误导。
The question of whether any non-human species displays episodic memory is controversial. Associative accounts of animal learning recognize that behaviour can change in response to single events but this does not imply that animals need or are later able to recall representations of unique events at a different time and place. The lack of language is also relevant, being the usual medium for communicating about the world, but whether it is critical for the capacity to represent and recall events is a separate matter. One reason for suspecting that certain animals possess an episodic-like memory system is that a variety of learning and memory tasks have been developed that, even though they do not meet the strict criteria required for episodic memory, have an 'episodic-like' character. These include certain one-trial learning tasks, scene-specific discrimination learning, multiple reversal learning, delayed matching and non-matching tasks and, most recently, tasks demanding recollection of 'what, where and when' an event happened. Another reason is that the neuronal architecture of brain areas thought to be involved in episodic memory (including the hippocampal formation) are substantially similar in mammals and, arguably, all vertebrates. Third, our developing understanding of activity-dependent synaptic plasticity (which is a candidate neuronal mechanism for encoding memory traces) suggests that its expression reflects certain physiological characteristics that are ideal components of a neuronal episodic memory system. These include the apparently digital character of synaptic change at individual terminals and the variable persistence of potentiation accounted for by the synaptic tag hypothesis. A further value of studying episodic-like memory in animals is the opportunity it affords to model certain kinds of neurodegenerative disease that, in humans, affect episodic memory. An example is recent work on a transgenic mouse that over-expresses a mutation of human amyloid precursor protein (APP) that occurs in familial Alzheimer's disease, under the control of platelet derived (PD) growth factor promoter (the PDAPP mouse). A striking age- and amyloid plaque-related deficit is seen using a task in which the mice have to keep changing their memory representation of the world rather than learn a single fact.
Good luck to everyone!
关于暴龙是食腐动物还是食肉动物 de课外阅读
阅读次数：543
thousandlife 2002-08-29 13:51:20
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关于暴龙tyrannosaurus是食腐动物scavenger还是食肉动物carnivore、predator
这几天总有人发现ets阅读的原文章，比如北欧海盗；昨天我在discovery上看到一个专题报道是关于暴龙的讨论，我留意到jj中的材料很少，可能是这篇文章较难或者比较多的名词不好记忆，所以在这里把discovery长达一个小时的节目总结一下，希望对阅读有用，也请考试中读过该文章的人出来指正。重申一下，这只是一点课外知识的补充，不要影响大家答题。
说长久以来人们一直把暴龙看成是凶猛的食肉动物，原因是早先一个学家主观地如是描绘恐龙，还说恐龙是直立行走、尾巴拖地。
片子主要介绍了一帮人在一个地方挖骨头，其带头人反驳了这一无证据的观点，同时提出了暴龙食腐动物的主张，且配以各方面的证据：
一、在三角龙头上的齿痕（jj上提到文中有）
这个学者拿一个三角龙的头骨，上面有很多小坑；众所周知，暴龙在所有恐龙中有最强大的牙齿，这些小坑正好能容下它们牙齿，证明是暴龙咬的，但不能说明是食肉动物还是食腐动物。但是有一块骨头上的坑可以说明是食腐动物，因为逻辑上讲暴龙必须先吃掉外面所有的肉和骨头才有可能碰到里面这块骨头，所以证明暴龙是
慢慢吃的食腐动物。
二、股骨径骨的比较
这两块腿上的骨头，当前者比后者长时，这种动物就善于奔跑。学家门有这种比例来判断一种动物奔跑的速度，发现暴龙的前者短，证明它门不善奔跑。
三、饶骨尺骨（我觉得这个最有说服力不过可能不会考）
暴龙的前肢上的两块骨头--就是小臂，短于肱骨--就是大臂，这说明它门的双手根本无法接触，它们用手也不能将猎物送至嘴边（太可怜了），甚至它们跌到了都很难靠四肢支撑再站起来。而公认的食肉动物，一种小的xx龙，它的前肢就很发达很长，且付赠利爪弯钩。
四、嗅觉
通过研究暴龙的头骨（不是周星驰的那个），学家发现恐龙的视觉神经很弱，这对于捕食是不利的；同时它的嗅觉神经很发达。接着他又对比了另一种食腐动物-xx鹫---这家伙可以发现25miles以外的肉味，它的嗅觉神经与暴龙的惊人的相似。再此验证了暴龙食腐。
五、丑陋的外表
大凡食腐动物都有丑陋的外表，如土狼、秃鹫，意在赶跑其他动物，而暴龙巨大丑陋。
再来一篇关于气候与动物灭绝(From 国家地理杂志)
阅读次数：478
smartom 2002-08-30 19:20:36
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看了几百篇ETS的科技文章，发觉自己越来越喜欢看这些东东，大家有机会的话看看明珠台和国际台，国家地理频道之类的节目，长知识，还可以练听力。
The Sixth Extinction
Text by Virginia Morell
Photographs by Frans Lanting
The first orange rays of the sun are just beginning to touch the saw grass prairie of Everglades National Park in Florida when our helicopter pilot lifts off from a small airport nearby. He turns low over the park, skimming above the gray-green grasses and morning mist. Here and there small stands of pencil-thin native slash pine show dark green against the pale grasslands. But it’s the open marshy prairie that we seek, home to the endangered Cape Sable seaside sparrow. Heading south, the pilot searches for a particular point on a transect map, then banks and flies due west. Twenty minutes later we’re on the ground. “Here’s your first spot,” he says over the radio to Stuart Pimm, the conservation biologist seated beside me in the back. In front another biologist, Sonny Bass, gives us the thumbs-up sign. Pimm and I, dressed in olive green flight suits and white helmets, jump into the wet marsh and run a short way from the helicopter.
For a moment this seems almost like a scene from Apocalypse Now. The helicopter’s blades whip the air, bending the grasses in a wide swath all around and obliterating every sound except the wap-wap-wap of its rotors. As it peels away, ferrying Bass to the next site a kilometer away, Pimm removes his helmet and turns to me. “Welcome,” he says, his voice rising above the fading roar of the helicopter, “to the front lines of saving biodiversity.”
An avuncular researcher from the University of Tennessee, Pimm is not merely being theatrical. Based on his and his colleagues’ calculations, some 50 percent of the world’s flora and fauna could be on a path to extinction within a hundred years. And everything is affected: fish, birds, insects, plants, and mammals. By Pimm’s count 11 percent of birds, or 1,100 species out of the world’s nearly 10,000, are on the edge of extinction; it’s doubtful that the majority of these 1,100 will live much beyond the end of the next century. The picture is not pretty for plants either. A team of respected botanists recently reported that one in eight plants is at risk of becoming extinct. “It’s not just species on islands or in rain forests or just birds or big charismatic mammals,” says Pimm. “It’s everything and it’s everywhere. It’s here in this national park. It is a worldwide epidemic of extinctions.”
Such a rate of extinction has occurred only five times since complex life emerged, and each time it was caused by a catastrophic natural disaster. For instance, geologists have found evidence that a meteorite crashed into Earth 65 million years ago, leading to the demise of the dinosaurs. That was the most recent major extinction. Today the Earth is again in extinction’s grip—but the cause has changed. The sixth extinction is not happening because of some external force. It is happening because of us, Homo sapiens, an “exterminator species,” as one scientist has characterized humankind. The collective actions of humans—developing and paving over the landscape, clear-cutting forests, polluting rivers and streams, altering the atmosphere’s protective ozone layer, and populating nearly every place imaginable—are bringing an end to the lives of creatures across the Earth. “I think we must ask ourselves if this is really what we want to do to God’s creation,” says Pimm. “To drive it to extinction? Because extinction really is irreversible; species that go extinct are lost forever. This is not like Jurassic Park. We can’t bring them back.”
In Pimm’s eyes people should be stewards of their neighboring species. That’s why he’s here at dawn in the Everglades, fighting to save the life of a little brown-and-white songbird with a smattering of gold feathers above its eyes.
Found only in this park, Big Cypress National Preserve, and nearby areas, the Cape Sable sparrow was once fairly common in the Everglades’ hundred square miles [160.9 square kilometers] of prairie lands, which lie adjacent to its better known “river of grass.” In 1992 the sparrow’s population registered a healthy 6,400 individuals. By 1995 the sparrow’s numbers had taken a nosedive: Its population dropped by 60 percent to 2,600. “It was clearly on its way out,” says Pimm, turning to set his helmet on the ground. “And to me that was unconscionable. In a national park of this size [the Everglades encompasses 1.5 million acres] (.6075 million hectares) and in the richest country in the world, species shouldn’t be going extinct because of our actions. These areas, after all, were set up for their protection.”
Raising his binoculars, Pimm surveys the surrounding grasses, then cups his ear to listen for the sparrow’s call. “Ahhh, there’s one. Do you hear it? Listen for a chit-chit-tweeeee,” he says, imitating the bird’s short, quick notes and insect-like buzz. We stand silently, and a few moments later the call comes again, clear and brazen in the still morning air. “That’s the male defending his territory; the birds have just started nesting, and so this is the best time to get a count of their population.” Through our binoculars we spot this throaty male, perched at the end of a swaying grass stalk, his beak open, singing to the sky.
Throughout the three-month nesting period Pimm and Bass make these counts, flying a different line of their transect map each dawn and stopping at sites spaced precisely a kilometer (0.6 mile) apart to look and listen for the birds. The resulting data give them not only a count of the number of eligible males but also a map of where the birds prefer to build their nests. And that, in turn, has revealed what is harming them: Too much water. “The birds start nesting in the middle of April,” Pimm says. “They weave the grasses together to form a bowl about three inches [76.2 millimeters] off the ground.”
Because they nest so close to the ground, there can’t be any standing water if they’re to raise a brood successfully. But water throughout and around the Everglades is managed and controlled by two agencies, the South Florida Water Management District and the Army Corps of Engineers. Water, which naturally would have flowed throughout the park, is held in reservoirs, channeled in dikes, and, above all, prevented from spilling into bordering farms and the suburbs of Greater Miami. To water managers, say Pimm and Bass, the drying western prairies of the Everglades in the spring look like an excellent place to dump excess water, which is what happened for several years beginning in 1993. While this protected some homes and roads, it has proved a disaster for the sparrow and, the biologists suspect, for other species, including many wading birds, such as egrets and herons whose nesting patterns have also been disrupted. “We’re losing the sparrow and probably other species just because of water management decisions,” says Bass on the flight back to the airport.
“Admittedly, it is a big problem managing the water here, especially in stormy years. But all it takes is holding off a couple of months, as the agencies did last year, to let the birds nest and rear their young. It’s a matter of making the right decision.”
If the Cape Sable sparrow’s nesting grounds are not flooded, Pimm and Bass think their population will begin to increase.
For other species, though, no decision will change their fate; they are simply doomed to disappear from Earth.
In London, at the Royal Botanic Gardens at Kew, two horticulturists lead the way through a greenhouse, stopping to point out plants, from shrubs to spindly trees, that no longer exist in the wild. Kew researchers hope eventually to return some to their homelands. But for others the greenhouse is the end of the line.
“Now that poor thing, an Encephalartos woodii, hasn’t had sex in about a hundred years,” says Stefan Czeladzinski, a horticulturist-in-training, referring to one of the trees. “It’s one of our living dead.” The plant, about five feet [1.5 meters] tall with leathery leaves, is from Natal in South Africa. It is a dioecious species, meaning that its individuals are either male or female. In this case the plant is a male, and no females are known to exist. “Botanists have combed Natal looking for one, but they’ve never found it,” says Czeladzinski. This survivor comes from cuttings from the last wild plant, which was moved to a botanical garden decades ago. All E. woodii plants alive today, including the lonely Kew specimen, are clones of that wild male; they are genetically identical and will never reproduce naturally unless a female is found.
And it’s not just the Encephalartos that has been lost. Most of the native flora of many islands is extinct, beaten out by species that settlers introduced from Europe more than 300 years ago. “In some islands the habitats were already destroyed by the time the first botanists arrived,” says Michael Maunder, a tall, dark-haired conservation biologist at Kew who specializes in the recovery of critically endangered plants. “We’ve managed to piece the flora together by reading travelers’ diaries, collecting pollen from soil samples, and having bits of wood identified. But we only have a shadow of an idea of what was once there.”
Because the species on islands are often endemics—meaning that they are found nowhere else in the world—their populations are typically small and consequently more prone to extinction. When a foreign plant is introduced—for example, the Chinese guava tree that blankets much of Mauritius, an island off Madagascar—it can become a weed that ends all others.
Kew Gardens and the Mauritian Wildlife Foundation have launched a project basically to weed the island of Mauritius. On the wall of his office Maunder has a large photo of an area known as the Black River Gorge, which retains remnants of Mauritius’s original forest. These plots, some a mere acre[0.41 hectare] in size, are caged in chain-link fences to keep out the deer and pigs, also introduced from Europe. Outside, as if biding its time, grows a thick, tangled mat of similarly introduced guava and privet.
“The plots are weeded every year,” Maunder says. “We can keep these small plots of natives going, but how do we extend them? Can we ever fully restore Mauritius?” Maunder only shakes his head.
Throughout the islands of the Indian Ocean and the South Pacific, the tale is much the same: extinctions being driven by species introduced by European explorers a few hundred years ago. But there was an even earlier round of extinctions in these and other places as humans moved out of Africa and into new lands. In Australia the arrival of the first people 50,000 to 60,000 years ago may have led to the demise of that island continent’s megafauna, which included 20 species of giant kangaroos, the marsupial lion, and diprotodons—herbivorous marsupials that resembled cow-size rodents.
“I’ve no doubt that people hunted them to extinction,” says Tim Flannery, a mammalogist at the Australian Museum in Sydney, who has investigated his country’s extinctions, past and present. “It’s the same story in New Guinea and New Zealand. There you can still find some of the evidence, such as piles of bones from the giant moas [large, flightless birds] that the Maori killed until there were no more.”
“The same thing happened here,” says Dolores Piperno, an archaeologist at the Smithsonian Tropical Research Institute in Panama, giving a quick smile and a sigh almost simultaneously. “Let me show you something.” She walks briskly across the tile floor of her office and riffles through a row of files. From one she pulls out a large chart and unfolds it on her desk. It’s a graph of plant fossils collected from sediments taken from a lake in central Panama, and it spans a period from 14,000 years ago to the present.
Fourteen thousand years ago the diversity of trees and plants was relatively modest, reflecting the tail end of the last ice age in the tropics. But by 11,000 years ago, as Panama began to warm up, the variety of flora increased dramatically. Piperno traces this burst of plant life with her forefinger as the graph makes an upward spike, but then the line takes a sudden downward plunge, as if tracking the collapse of the stock market in 1929. “That,” she says, tapping the graph, “is when people began practicing slash-and-burn agriculture here, about 7,000 years ago. That’s what people can do to a forest with a stone ax and fire. It shows that the idea of the noble savage—that people in the past in simpler societies lived in harmony with the natural world—isn’t true. We humans have short-term goals. That’s what makes saving species and conserving the environment for the long term so hard. We want results now.”
But that short-term outlook can also work against people by eliminating potentially useful species. “We have not yet identified all the plants on Earth,” says Sir Ghillean Prance, the director of Kew Gardens, “and we’re losing them, I’m afraid, faster than we can catalog them.” Because so many of our most effective medicines, from aspirin to morphine, come from plants, Prance worries that in losing the flora of the world, we’re also losing the possibility of finding new drugs and chemicals.
“Every time we lose a species, we lose an option for the future,” he says. “We lose a potential cure for AIDS or a virus-resistant crop. So we must somehow stop losing species, not just for the sake of our planet but for our own selfish needs and uses.” The Cape Sable sparrow, of course, is not likely to lead to a cure for cancer or to any other earthshaking discovery. Nor are most species around us. What would it matter if this little bird, or any of the 1,100 others on Pimm’s list, becomes extinct? That thought crosses my mind one morning while joining his team of bird banders in the Everglades.
To trap the sparrows, the team watches the males to identify each individual’s nesting territory. The banders then set up a mist net nearby and play a tape recording of another male’s song, fooling the resident male into thinking a rival has arrived to court his mate. That kind of cheeky behavior elicits an immediate response from the male in this territory. He swoops in low over the grass, stops for a few seconds atop a single blade to sing his own territorial song, and then flies determinedly into the net, where he thinks his competitor is lurking.
Two banders rush forward to catch him. They weigh and measure him and gently fasten two yellow bands onto his left leg. “Would you like to let him go?” asks Dave Okines, the chief bander. He shows me how to hold the sparrow’s legs between my first and second fingers, so that he sits upright on the top of my hand. For a brief moment, I keep him there, feeling his warmth, admiring the bright gold of his eyebrow feathers. Then I open my hand and he’s gone in a flash, and I allow myself the thought that the sixth extinction is not inevitable. If humans are the cause, they can also be the solution.
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anan28:《又找到一篇火星上有生命的文章，很像JJ！ 》（8.24)
site:
http://cass.jsc.nasa.gov/lpi/meteorites/alhnpap.html
JJ里提到的人名及AHL8400这个东东都有！大家好好看看！
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我自己看了一下，确实很长，讲了很多科学家的观点，每一篇后面都附上作者自己的评述（语气像极了GMAT的CR和AWA的八股味！呵呵）。。如果时间不够的同志们只看下面的文章就可以了。
Schopf J.W. (1999) Breakthrough Discoveries. Ch. 5 (p. 91-117) in Evolution! Facts and Fallacies (ed. J.W. Schopf) Academic Press, NY.
The author recalls his experiences leading up to the NASA press conference at which D.S. McKay and colleagues announced their claim of evidence for ancient martian life in ALH 84001. The validity of the claim and its evidence are discussed in the context of two failed extraordinary claims in paleontology.
The course of science is littered with claims of extraordinary breakthroughs and insights. Correct claims are well-chronicled, and often led to Nobel prizes. Failed claims reveal a rarely-seen side of science: error, faith, despair, and sometimes redemption. Dr. Schopf considers three extraordinary claims: the fossil of a purported man drowned in the Noachian deluge; hoax fossils of birds, stars, spiderwebs, the name of God in Hebrew, etc., perpetrated upon a German paleontologist; and evidence for fossil life in meteorite ALH 84001.
In 1725, Dr. J.J. Scheutzer discovered fossil bones in limestone from Baden (Germany), and interpreted them as a human skeleton, from a man drowned in the Noachian flood. His discovery was hailed as scientific proof of the Bible, although many scholars harbored doubts. After Scheutzer's death, and the conquest of his home Holland by France in 1810, Georges Cuvier was granted permission to "clean" the specimen. Cuvier confirmed his suspicions (based on published drawings) that the skeleton actually came from a large salamander.
Also in 1725, Professor J. Beringer of Würzburg (Germany) dug up a collection of rocks with incised and relief depictions of animals (bees, scorpions, lizards, aphids, spiderwebs, a honeycomb, a bird with eggs), flowers, stars, a smiling sun, and the name of God in Hebrew. Professor Beringer quickly published a treatise on these marvelous rocks, but soon realized that he had been hoaxed. He requested a judicial hearing, where two rival academics were implicated. Beringer was exonerated, and continued his distinguished career.
In 1996, Dr. D. McKay and colleagues at the Johnson Space Center announced at a press conference that they had uncovered evidence, in a meteorite, for life in Mars' distant past. Their first line of evidence was the presence of carbonate, sulfide and oxide minerals together in the rock. McKay et al. suggested that the association of these minerals could be related to life, but the association does not prove life. Second, McKay's group found minute crystals of magnetic iron oxide, which are strikingly similar to those found in some Earth bacteria. Yet these particles cannot be distinguished from similar magnetic grains formed without life. The third line of evidence was the presence of organic chemical compounds associated with the carbonate minerals, yet the specific organic compounds discovered can form readily without any intervention from life. Finally, McKay and colleagues presented images of "features resembling terrestrial microorganisms..." as possibly being fossils of martian microorganisms.
The "features resembling terrestrial microorganisms..." are actually similar in shape only, not in size. They are up to 30 x 130 nm (billionths of a meter) long. This is about 1/200 the volume of the smallest known terrestrial organism, which is a parasite: it is too small to contain all the biochemistry needed for life as we know it. If we assume that the martian organism had a cell wall ~ 6 nm thick, its volume is 1/2000 that of the smallest known Earth organism.
The question of life in ALH 84001 cannot be answered definitively with the available data. Dr. Schopf draws three lessons from the stories of extraordinary scientific claims: that "headlines win," that scientists are human, and that science is self-correcting -- faulty conclusions will eventually be found out.
This chapter is not a peer-reviewed scientific document, but gives a fascinating historical account of the ALH 84001 controversy. Dr. Schopf was the designated skeptic at the first NASA press conference on ALH 84001, the curmudgeon who found the flaws in the theory McKay built. Particularly intriguing is Schopf's story of his first meeting with McKay's group -- by his account, they had tentatively identified carbonate pancakes in ALH 84001 as whole fossil foraminifera.
This chapter was adapted from a longer work by Dr. Schopf, Cradle of Life, to be published in 1999 by Princeton University Press.
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anan28: 《找到一篇文章关于VINLAND map真伪的，与真题很像。可以试试！》（8.14)
在网上好不容易才搜到的，特贴于此。
http://www.yalealumnimagazine.com/issues/96_05/vinland_map.html
比较长，耐心点读，权当练阅读。
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Tales of the "Un-Fake"
The reputation of a map donated to the Beinecke Library and later suspected of being a fraud has been rehabilitated, but the process highlights the problems of proving a document's authenticity beyond a doubt.
May 1996
by Jennifer Kaylin
It was the fall of 1965, and a small group of Yale scholars could barely contain their elation. After months of secrecy, they had just announced receipt of an extraordinary gift, a wrinkled piece of parchment known as the Vinland Map. Hailed as the "cartographic discovery of the century," the document was said to prove that Leif Ericson, and not Christopher Columbus, was the true discoverer of America. James Tanis, the University Librarian at the time, called the Vinland Map "the most exciting single acquisition of the Yale Library in modern times, exceeding in significance even Yale's Gutenberg Bible and Bay Psalm Book"; Alexander O. Vietor, Yale's curator of maps, declared it "the greatest treasure of the Yale Map collection." To coincide with the announcement, Yale University Press triumphantly published a book, The Vinland Map and the Tartar Relation.
But elation soon turned to mortification. Skeptical of the process used to authenticate the Vinland Map, several scholars called for more sophisticated testing, and in 1972, an investigation by an independent laboratory forced the University to concede that the Vinland Map "may be a forgery," subjecting Yale to one of the more embarrassing public humiliations in its history.
One would think that an apparent gaffe of this magnitude would have put an end to the saga of the Vinland Map, but last year, yet another group of scientists presented new evidence suggesting that the map was indeed a genuine pre-Columbian document. This finding prompted Yale University Press to publish a revised edition of its original book. The handsome volume arrived in bookstores this February, but not without an introduction conceding that doubts about the map might never be entirely eliminated.
Even the map's most ardent supporters had been shaken by the on-again-off-again authentication saga, but they were hardly alone. In an era of rapidly changing technology, when frauds abound and even government mints can stay only a step or two ahead of counterfeiters, the people who make decisions about what is real and what is fake are under enormous pressure. That pressure grows even more intense when the object in question has a potential for historic and monetary value. If scholars and scientists using the latest equipment could study the Vinland Map for almost 40 years and still not reach a unanimous conclusion on its authenticity, what does that say about the chances that the genuineness of any artifact can be verified with certainty?
The journey that led to the rehabilitation of the Vinland Map began in 1957, when a New Haven rare-book dealer named Lawrence Witten bought the document for $3,600 from an Italian book seller. To the untrained eye, the map could not have been less impressive. Drawn on a sheet of parchment about the size of a place mat, it had become brownish and rippled with age. There were none of those colorful renderings of mythic sea monsters or the decorative calligraphy one associates with early maps -- just a faded and imprecise wavy black outline of several large land masses.
Nevertheless, Witten stopped by the Yale Library to show his acquisition to Alexander Vietor and Thomas E. Marston, the curator of Medieval and Renaissance Literature. Both were impressed by the document, in which they recognized a remarkably accurate representation of Greenland. But next to that was a large area labeled "Vinlanda Insula." The scholars concluded that the "island" was actually the coastline of North America. Even more intriguing, a Latin inscription in the upper left corner described how Leif Ericson and Bjarni Herjolfson had sailed from Greenland and discovered the new land, which they named Vinland. The scholars concluded that the map had been drawn about 50 years before Columbus's voyage by an unknown European cartographer using since-lost records left by Viking explorers, and that the discovery itself would have been made about 500 years before Columbus.
Historians had long been aware of Norse sagas about pre-Columbian voyages to North America, but efforts to find any cartographic evidence of these excursions had failed. Suddenly, it appeared to Vietor and Marston, the proof had dropped into their laps.
Alerted to the find, an anonymous donor (who was later identified as Paul Mellon '29, one of Yale's most durably generous benefactors), purchased the map for $1 million and turned it over to the Beinecke.
Even then, however, the Yale scholars were not without their reservations. Unaccountably, the map had been bound during the 19th century with a medieval manuscript called the Tartar Relation, which related the findings of a 13th-century expedition into Asia to the land of the Tartars. The problem was that the map and the Relation didn't seem to have anything in common except that they were bound together. To further muddle things, the binding was relatively new, and a cluster of worm holes in the map didn't match the worm holes in the Relation. Until these disparities could be adequately explained, the authenticity of the map would have to remain suspect.
But in 1958, an amazing stroke of luck seemed to provide the answer. Marston invited Witten over to inspect the bindings of some rare books he'd recently bought from a London company. As Witten leafed through one of the books -- a medieval encyclopedia called Speculum Historialia -- he noticed that it was made up of an odd combination of parchment and paper pages. Recalling the same feature in the Tartar Relation, he compared the water marks and found that they were the same. He then found that a worm hole on the first page of the Relation exactly matched up with one on the last page of the encyclopedia. Three pairs of worm holes on the map aligned exactly with those on the first page of the encyclopedia. It was therefore clear that the map, the Tartar Relation, and the encyclopedia had once all been parts of the same book -- and that evidence contained in the encyclopedia could now be used to authenticate the map.
Eight years of arduous research followed, culminating in the publication of the Press's lavish book, which described in detail the scholarly and scientific scrutiny to which the map had been subjected. Chester Kerr, who was then the director of the press, has vivid memories of that time. "We planned to publish the book in the spring," recalls Kerr, "but there was a delay in getting the proofs read, which meant it couldn't come out until June. I didn't want it to get lost in the summer, light-reading season, so we decided to wait until the fall." Kerr and the other major players thought it would be timely to release the book on October 9, Leif Ericson's birthday, but they decided to wait until the following Monday to accommodate everyone's schedules. "That was where I made my great mistake, because that turned out to be Columbus Day," Kerr recalls. "I was always accused of doing this deliberately to discredit Columbus in favor of Leif Ericson, but the truth is that it was a complete accident."
Angered by what appeared to be an insult to a large population of Italian-Americans, public figures across the country scrambled to register their indignation. Jimmy Durante quipped that although he was not "poissonally" acquainted with Columbus, he knew that when the explorer arrived in America, he "played only to Indians -- there were no Norwegians in the audience!" John Lindsay '44, '48LLB, a congressman who was then a candidate for mayor of New York (where Italian-American voters far outnumbered Norse-Americans), declared that "to say Columbus didn't discover America is as absurd as saying DiMaggio doesn't know anything about baseball or that Toscanini and Caruso weren't great musicians." It wasn't long before the popular press took up the story, and the combined notoriety helped turn the book into a best-seller.
"It was an amazing time," recalls Anna Glen Vietor, the widow of Alexander Vietor. "My husband was flooded with phone calls from people asking him why he hated Columbus. Then there were the cartoons: Indians sitting in a circle raising their glasses, saying 'Skoal' as the Santa Maria pulled up to the shore -- things like that. If it hadn't been played up by the media the way it was, it would have been a perfectly good scientific affair."
But the Columbus Day brouhaha wasn't the only upheaval the map encountered. At a 1966 conference convened by the Smithsonian Institution to discuss the map, lingering doubts about its authenticity prompted Yale to commission an independent laboratory to reexamine the map. Walter C. McCrone, a Chicago microscopist and expert on air pollution, removed 29 particles of vellum and ink from the map. His X-ray analysis showed that the particles consisted of anatase, a crystalline form of titanium dioxide that is rare in nature -- and was not commercially available as a white pigment until 1920. Devastated, but facing what appeared to be incontrovertible scientific evidence, Yale conceded that the map might be a fake.
As horrifying as this episode was for Yale scholars, they might have taken comfort in the knowledge that they were in good company. History is littered with examples of suspected and confirmed forgeries, not to mention revisionist discoveries. Experts are still debating the authenticity of the Shroud of Turin, the cloth supposedly used to wrap the body of Christ after he was taken down from the cross and which is said to bear his image. More recently, a statue that stood unnoticed for years in the lobby of a stately New York City home designed by Stanford White for the Payne Whitney family has been reassessed by at least one reputable scholar as a work by Michelangelo.
More common are forgeries that were ultimately exposed. Euripides, Themistocles, and Socrates are just three ancient writers whose letters and works were forged. In the late 18th century, William Henry Ireland claimed to have discovered unknown manuscripts by Shakespeare, going so far as to create a new "Shakespeare" play, Vortigern and Rowena. In 1928, the Atlantic Monthly published a series of articles based on what turned out to be forged love letters from Abraham Lincoln to Ann Rutledge. The "diaries" of Benito Mussolini even fooled his son, Vittorio, and the forging of Howard Hughes's autobiography by Clifford Irving was only exposed when the reclusive billionaire emerged from seclusion to denounce its authenticity.
One of the more spectacular American forgery cases involved a con artist named Mark Hofmann, who sought to rewrite Mormon theology by creating bogus documents that included the so-called "White Salamander Letter," which described the finding of the "gold plates" on which Mormonism is founded. But perhaps the most dramatic forgery attempt of modern times occurred in 1983 with the appearance of 62 diaries supposedly written by Adolf Hitler. The West German photo weekly Stern paid $3.8 million before discovering its error, and Newsweek magazine was left red-faced after it devoted a cover story to what turned out to be total fabrications.
These examples, of course, all involve forgeries that were eventually exposed; the case of the Vinland Map differs in that it could well be authentic. This makes its story all the more intriguing, and the detective work of the scholars assigned to unravel the mystery that much more difficult.
When investigating a document like the Vinland Map, experts use a combination of science and scholarship, drawing on historical evidence as well as physical data. Improved technology -- high-powered microscopes, ultraviolet light, micronometers, X-rays, and cyclotrons are but some of the tools -- now enables scientists to expose fraudulent artifacts with greater ease, but a thorough knowledge of the culture in which the item was supposedly produced is also essential. For example, scholars were immediately suspicious of a notebook that was purportedly the diary of Jack the Ripper because it contained phrases inconsistent with Victorian prose. The simple fact that the diary was written in the sort of scrapbook usually used for mounting postcards and photographs rather than recording personal histories added to the doubts, which were eventually confirmed.
Jacqueline Olin of the Smithsonian Institution's Conservation Analytical Laboratory says teamwork is often critical to authenticating an artifact. Just as an assortment of health-care specialists will work together to diagnose a disease and develop a course of treatment, experts representing a range of different fields will join forces to analyze a questionable document. In his book, Forging History, Kenneth W. Rendell writes that the "authentication of historical letters and documents uses an analytic approach that can be illustrated and proven. It is true that an initial element that many call 'intuition' does play an important part in any examination of questioned documents; but what is frequently called intuition is a simultaneous observation of combinations of facts reflected against the mental images stored during decades of experience, giving an indication of whether the document in question meets the general criteria of genuine documents of the period and circumstances." Rendell adds that "knowing the psychology of forgers is almost as important as knowing how to analyze handwriting."
The case for and against the Vinland Map has always hinged on the scientific evidence, but the ways in which that evidence is gathered and evaluated are constantly changing. McCrone's technical data, gathered in the early 1970s, seemed at the time to be definitive. As time passed, however, a challenge to the original results became all but inevitable. When it happened -- at the behest of a group of supporters who remained unwavering in their belief that the map was authentic -- no one was sure what the result would be. But in 1985, the pro-Map forces got the news they had been hoping for. Physicists at the University of California at Davis had uncovered new evidence that contradicted McCrone's findings and tipped the scale back toward the view that the document was genuine.
Using a powerful cyclotron to fire a beam of protons through the map, the UCD team had generated X-rays from which all elements present in the ink and parchment could be identified and quantified. Thomas A. Cahill, who headed the project, reported that the ink contained only trace amounts of titanium, amounts consistent with other medieval documents he had studied. "We tested 150 parchment documents from that period, and the findings were similar," he says.
Another McCrone finding that had hurt the map's claim to authenticity was that the anatase appeared in the form of crystals, rather than in the irregular chunks and shards that are found in nature. Cahill acknowledges the point, but argues that the condition is likely to be the result of modern contamination rather than a modern forgery. "Such particles could be easily pressed into the map during handling," he says. "This is in fact almost impossible to avoid." As for McCrone's contention that the anatase was used to make the map's yellow lines, Cahill says experiments proved it was not present in sufficient quantities to produce visible marks.
McCrone, who has also tested the Shroud of Turin and is convinced that it is a forgery, stands by his position that the Vinland Map is "a modern production." In a dramatic gesture emphasizing just how heated the argument has become, McCrone showed up, uninvited, at a symposium held at Yale on February 10 to discuss the map. McCrone remained silent throughout, but when the symposium ended he handed out a copy of the report he said he would have submitted had he been asked. It was titled: "The Vinland Map, Still a 20th-Century Fake." Among McCrone's supporters is Kenneth M. Towe, a senior research geologist at the National Museum of Natural History. "Cahill's instrument can find an element like titanium dioxide, but not a mineral, such as anatase," Towe says. "It's like having an instrument capable of detecting carbon but not being able to tell whether it's graphite or a diamond."
How can reputable scientists and scholars reach such contradictory conclusions? If authenticating an artifact were an objective science, devoid of the capriciousness of human emotions and free from the vagaries of interpretation, consensus might be easier to reach. But bias, ego, emotion, even wishful thinking -- in short, the human factor -- are very much a part of the equation. " eople think that scientists, with their white lab coats, are not subject to human frailties," says Wilcomb Washburn, director of the American Studies Program at the Smithsonian Institution. "But human emotions do affect their considerations of the truth."
The probing is not over yet. The results of a carbon-14 dating test performed on the map are expected later this year.
It would be an understatement to say that the Vinland Map has been subjected to an unprecedented amount of controversy and study. It has aroused the passions of both scientists and historians, who remain divided over its authenticity, and even its advocates are forced to hedge their bets. Back in 1965, when the first Vinland Map book was published, Alexander Vietor wrote that it was designed to be a "preliminary worka springboard for further investigation." More than 30 years later, Washburn remains similarly circumspect. In the book's second edition, he writes that while the dispute over the map's authenticity may never be resolved, it "can now be said to have reached a new stage." Those who have been charging forgery "must now assume a defensive role and respond to those previously on the defensive."
Given such lingering doubts, it might seem surprising that Yale University Press would release a second edition of The Vinland Map and the Tartar Relation, which stops just short of declaring the map genuine. Despite the risk of another catastrophe of credibility, Press Director John Ryden says he had no qualms about publishing the revised work. "To the extent possible, the people involved have been vindicated," he says. "All the apparently damning evidence was overturned, which led us to conclude that the map had received a bum rap." Ryden also knows that scholars and scientists are limited in what they can do to authenticate a historic artifact. "You can never prove authenticity; you can only disprove it," he says, adding philosophically, "secretly, I feel that to leave a little bit of mystery is probably a good thing."
美国华人移民法
Chinese-American Men,
between 1890 and 1910(?)
History of the American West, 1860-1920
After the Civil War, immigrants again began to stream to the United States. Between 1870 and 1900, nearly 12 million immigrants arrived--more foreign-born people than had come to the country in the preceding 70 years. During the 1870s and 1880s, the majority came from Germany, Ireland, and England--the principal source of immigration before the Civil War. Even so, a relatively large group of Chinese immigrated to the United States between the start of the California gold rush in 1849 and 1882, when federal law stopped their immigration.
While the majority of immigrants came to settle in the United States permanently, many worked for a time and returned home with whatever savings they had set aside from their work. The majority of Chinese immigrants, for example, were single men who worked for a while and returned home. At first, they were attracted to North America by the gold rush in California. Many prospected for gold on their own or labored for other miners. Soon, many opened their own businesses such as restaurants, laundries, and other personal service concerns. After the gold rush, Chinese immigrants worked as agricultural laborers, on railroad construction crews throughout the West, and in low-paying industrial jobs.
With the onset of hard economic times in the 1870s, other immigrants and European Americans began to compete for the jobs traditionally reserved for the Chinese. With economic competition came dislike and even racial suspicion and hatred. Such feelings were accompanied by anti-Chinese riots and pressure, especially in California, for the exclusion of Chinese immigrants from the United States. The result of this pressure was the Chinese Exclusion Act, passed by Congress in 1882. This Act virtually ended Chinese immigration for nearly a century. As the following documents suggest, there were many opinions about this issue. |
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