bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Analysis of Conservative Maps: A Possible Foundation of Nonextensive Phenomena
Authors: Baldovin Fulvio
Published: November 2020

We discuss the sensitivity to initial conditions and the entropy production of low-dimensional conservative maps, focusing on situations where the phase space presents complex (fractal-like) structures. We analyze numerically the standard map as a specific example and we observe a scenario that presents appealing analogies with anomalies detected in long-range Hamiltonian systems. We see how the Tsallis nonextensive formalism handles this situation both from a dynamical and from a statistical mechanics point of view…. In recent years, the Tsallis extension of the Boltzmann-Gibbs (BG) statistical mechanics [9, 26], usually referred to as nonextensive (NE) statistical mechanics, has become an intense and exciting research area (see, e.g., Tsallis [25]). The q-exponential distribution functions that emerge as a consequence of the NE formalism have been applied to an impressive variety of problems, ranging from turbulence, to high-energy physics, epilepsy, protein folding, and financial analysis. Yet, the foundation of this formalism, as well as the definition of its area of applicability, is still not completely understood, and it stands as a present challenge in the affirmation of the whole proposal. An intensive effort is currently being made to investigate this point, precisely in trying to understand: (1) which mechanisms lead to a crisis of the BG formalism; and (2) in these cases, does the NE formalism provide a "way out" to some of the problems? A possible approach to these questions comes from the study of the underlying dynamics that gives the basis for a statistical mechanic treatment of the system. This idea is not new. Einstein, in his critical remark about the validity of the Boltzmann principle [10], was one of the first to call attention to the relevance of a dynamical foundation of statistical mechanics. Another fundamental contribution is Krylov's seminal work [14] on the mixing properties of dynamical systems. In one-dimensional (dissipative) systems, intensive effort has been made to analyze the properties of the systems at the edge of chaos, i.e., at the critical poin that marks the transition between chaoticity and regularity [6, 8, 16, 19, 18, 23, 27].
The Pricing of Stock Options
Authors: Borland Lisa
Published: November 2020

We describe how a stock price model based on nonextensive statistics can be used to derive a generalized theory for pricing stock options. A review of theoretical and empirical results is presented…. In 1973, Black and Scholes [1] and Merton [12] published their seminal papers which developed a theory of the fair price of options. Scholes and Merton were later to receive the 1997 Nobel prize for this famous work (Fisher Black had unfortunately passed away two years earlier). Options are important financial instruments which are traded in a huge volume all around the world on a variety of exchanges. There are options on underlying assets ranging from orange juice to gold, stocks to currency. In principle, an option is simply the right—but not the obligation—to execute some previously agreed upon action, for example, the right to buy or sell the underlying asset at some predetermined price, called the strike. It is not difficult to understand that the existence of such instruments could be extremely useful—for example, the right to buy an asset at a certain price protects against unforeseen events which could lead to huge price rises and thereby losses to someone who knows that they will need the asset at some time in the future. Similarly, the right to sell the asset at a certain price will protect against unforeseen drops in its value. These examples illustrate the use of options to hedge oneself against possible future events. Another use is more speculative: If a trader believes that the price of a stock will rise above a certain price at some date in the future, then it is in his interest to secure an option to buy the stock at some fixed lower price. Then, if the price of the stock does rise above that price, the trader can execute his option, just to turn around and resell the stock again at the higher market price.
The Architecture of Complex Systems
Authors: Latora Vito , Marchiori Massimo
Published: November 2020

At the present time, the most commonly accepted definition of a complex system is that of a system containing many interdependent constituents which interact nonlinearly. Therefore, when we want to model a complex system, the first issue has to do with the connectivity properties of its network, the architecture of the wirings between the constituents. In fact, we have recently learned that the network structure can be as important as the nonlinear interactions between elements, and an accurate description of the coupling architecture and a characterization of the structural properties of the network can be of fundamental importance also in understanding the dynamics of the system. In the last few years the research on networks has taken different directions producing rather unexpected and important results. Researchers have: (1) proposed various global variables to describe and characterize the properties of realworld networks and (2) developed different models to simulate the formation and the growth of networks such as the ones found in the real world. The results obtained can be summed up by saying that statistical physics has been able to capture the structure of many diverse systems within a few common frameworks, though these common frameworks are very different from the regular array, or capture the random connectivity, previously used to model the network of a complex system. Here we present a list of some of the global quantities introduced to characterize a network: the characteristic path length L, the clustering coefficient C, the global efficiency Eglob, the local efficiency Eloc, the cost Cost, and the degree distribution P(k). We also review two classes of networks proposed: smallworld and scale-free networks. We conclude with a possible application of the nonextensive thermodynamics formalism to describe scale-free networks. Watts and Strogatz [17] have shown that the connection topology of some biological, social, and technological networks is neither completely regular nor completely random. These networks, that are somehow in between regular and random networks, have been named small worlds in analogy with the smallworld phenomenon empirically observed in social systems more than 30 years ago [11, 12].
Monitoring Drought in the United States: Status and Trends
Authors: Wilhite Donald A. , Svoboda Mark D.
Published: November 2020

Drought occurs somewhere in the United States almost every year and results in serious economic, social, and environmental costs and losses. Drought is more commonly associated with the western United States because much of this region is typically arid to semiarid. For example, this region experienced widespread drought conditions from the late 1980s through the early 1990s. The widespread and severe drought that affected large portions of the nation in 1988 resulted in an estimated $39 billion in impacts in sectors ranging from agriculture and forestry to transportation, energy production, water supply, tourism, recreation, and the environment (Riebsame et al., 1991). In the case of agriculture, production losses of more than $15 billion occurred and especially devastated corn and spring wheat belts in addition to reducing exports to other nations. In 1995, the U.S. Federal Emergency Management Agency (FEMA) estimated annual losses attributable to drought at $6–8 billion (FEMA, 1995). Since 1995, drought has occurred in nearly all parts of the country, and many regions have been affected on several occasions and in consecutive years. Most of the eastern United States experienced an extremely severe drought in 1998– 99, and in parts of the southeast, drought occurred each year from 1999 through 2002, especially in Florida and Georgia. Figure 9.1 depicts nonirrigated corn yields for Nebraska for the period from 1950 to 2002. Nebraska is one of the principal agricultural states in the United States, and corn is one of its primary crops. The drought effects on yields are most apparent during the severe droughts of the mid-1950s, mid-1970s, 1980, 1983, 1988–89, and 2000. Extremely wet years, such as 1993 in the eastern part of the state, also depressed corn yields. Monitoring drought presents some unique challenges because of its distinctive characteristics (Wilhite, 2000). The purpose of this chapter is to document the current status of drought monitoring and assessment in the United States, particularly with regard to the agricultural sector.
An Early Graduate Program in Computers and Communications
Authors: Burks Arthur W.
Published: November 2020

This is the story of how, in 1957, John Holland, a graduate student in mathematics; Gordon Peterson, a professor of speech; the present writer, a professor of philosophy; and several other Michigan faculty started a graduate program in Computers and Communications—with John our first Ph.D. and, I believe, the world's first doctorate in this now-burgeoning field. This program was to become the Department of Computer and Communication Sciences in the College of Literature, Science, and the Arts about ten years later. It had arisen also from a research group at Michigan on logic and computers that I had established in 1949 at the request of the Burroughs Adding Machine Company. When I first met John in 1956, he was a graduate of MIT in electrical engineering, and one of the few people in the world who had worked with the relatively new electronic computers. He had used the Whirlwind I computer at MIT [33], which was a process-control variant of the Institute for Advanced Study (IAS) Computer [27]. He had also studied the 1946 Moore School Lectures on the design of electronic computers, edited by George Patterson [58]. He had then gone to IBM and helped program its first electronic computer, the IBM 701, the first commercial version of the IAS Computer. While a graduate student in mathematics at Michigan, John was also doing military work at the Willow Run Research Laboratories to support himself. And 1 had been invited to the Laboratories by a former student of mine, Dr. Jesse Wright, to consult with a small research group of which John was a member. It was this meeting that led to the University's graduate program and then the College's full-fledged department. The Logic of Computers Group, out of which this program arose, in part, then continued with John as co-director, though each of us did his own research. This anomaly of a teacher of philosophy meeting an accomplished electrical engineer in the new and very small field of electronic computers needs some explanation, one to be found in the story of the invention of the programmable electronic computer. For the first three programmable electronic computers (the manually programmed ENIAC and the automatically programmed EDVAC and Institute for Advanced Study Computer) and their successors constituted both the instrumentation and the subject matter of our new Graduate Program in Computers and Communications.
Building Foundations for Reading Success
Authors: Allen Janet , Landaker Christine
Published: November 2020

At a time when districts have mandated coverage of elaborate lists of content standards, most teachers are feeling the challenge of covering so much material with students who come to class lacking the interest, background knowledge or content language necessary for reading historical texts. An additional challenge affects our instructional decisions when we also must work with students who have no sense of the time and place in which they live. Christine’s 8th grade classroom offers us a great example of how difficult it is to teach, or even to know where to begin, when this combination of problems occurs. Christine and her students had just begun a unit on Colonial America, and Christine worked with her students to generate a list of information they would need to find in order to be experts on what life was like in one of the three Colonial regions. After generating their lists, students used three sources to create their descriptions of life in Colonial America: A History of US, the district-adopted textbooks, and related supplemental trade books. Imagine Christine’s surprise when one group of experts reported that colonists traveled by whores and communicated via cell phones! On days like this, we are reminded of how important it is to build background knowledge with students before asking them to read, write, or conduct research. Even our best students struggle to understand concepts that seem far removed from their lives, and our most struggling readers are often so overwhelmed they do not even attempt to read their assignments. As content teachers, we have four broad tasks:… • Assessing the knowledge base students bring to the study • Providing students with experiences that give them a rich and memorable context for their reading • Anticipating words and concepts that may make reading difficult • Helping students develop questions they would like to answer so that they have a purpose for reading… As we were writing this book, Christine reminded me just how important it is simply to ask students what they already know—before beginning teaching. She said she often starts class by writing the following statement on the board: “What do you already know or think you know about ___________?” She then records students’ answers on a chart or transparency.
France: Expertise and Friendship
Authors: Freidberg Susanne
Published: November 2020

Que voulons-nous manger?—What do we want to eat? The French government posed this question in 2000 as part of a Ministry of Agriculture project on l’Etats Generaux de l’Alimentation (EGA), or the “General State of Food.” It also recruited thousands of citizens to respond in surveys, discussion groups, and a national colloquium, which were all duly recorded, analyzed, and interpreted by market researchers. Described as an effort to promote debate and dialogue around the French public’s “true” food concerns, the EGA seemed an extraordinary overture from a government not known for soliciting public opinion on policy matters (Marris 1999). But then, it was an extraordinary time. In the previous five years, mad cows, dioxin chickens, and listeria had found their way into the French food supply; opposition to genetically modified organisms (GMOs) had mushroomed into a major political crisis; a millennial shipwreck off the Brittany coast had dumped huge quantities of potential carcinogens into some of the country’s richest fishing waters. Media coverage of these affairs had played up the roles of government officials who were either corrupt, incompetent, disingenuous, or simply unable or unwilling to address questions about possible food risks (Jaillette 2000; Mamère and Narbonne 2001). The government badly needed to show that it was listening, and that it could protect the public’s health. Yet the EGA findings, while inconclusive in many respects, did show that alleviating public anxieties about the food supply would take more than stricter safety measures (Joly and Marris 2001). For the French were concerned not only about mad cow disease and listeria, but also the loss of their culinary patrimony. In particular, they feared that globalization would force upon them the travesties of “Anglo-Saxon” food culture, from Big Macs to biotech maize. France’s fresh produce importers would probably find the EGA’s findings old but ironic news. After all, the importers had helped to globalize one prominent part of the French diet, namely fresh produce. For much of the past century France, unlike Britain, had produced much of its own fruit and vegetable supply.
Nitty-Gritty
Authors: Parini Jay
Published: November 2020

Okay, you’ve got your first job. I was there, 30 years ago, but— unfortunately—there was nobody around to write me the sort of letter I’m writing to you. I don’t even know you, but I feel a certain responsibility, mostly because I want to spare you some of the mistakes I made, to make your life in the classroom, in the academic village, a little easier. Like all advice, you can take it or leave it. One of the main things I can say to you is that every teacher, like every person, is different. You have to teach out of who you are. That is the only way you will succeed, as a professional, as a teacher and scholar, as a member of the community of scholars. You will have to adapt anything I say here to your own private vision, to some version of yourself. The essential journey in this profession is toward self-knowledge; this will involve getting lost in order to get found, losing your thread, having to revise your sense of reality over and over, frequently adjusting to new information, new contexts. In modeling this revisionary path, you will help your students to learn how to forge their own paths. I will assume that you went into the teaching profession because you thought you had a gift for teaching or scholarship—or both. You liked a few teachers along the way and you thought you could emulate their success. Perhaps you were just fascinated by the field: literature, physics, whatever. You wanted to spend your life around people fascinated by this field, who take their work in a given subject seriously. You liked, perhaps, the smell of the lab or library, the feel of scholarly journals in your hands. You enjoyed hearing intelligent people argue. That is probably as good a place to begin as anywhere, but you nevertheless have to make your way in the profession: among students and among your colleagues, some of whom will vote on your tenure. Again I will return to the basic advice: be yourself, but build on that notion, adding to yourself, amplifying yourself.
Application to real data
Authors: Pawlowsky-Glahn Vera , Olea Richardo A.
Published: November 2020

Methods for spatial correlation analysis and estimation of r-compositions introduced in the foregoing chapters are illustrated here by an example that draws upon real data taken from the Lyons West oil field located in west-central Kansas, USA. Data consist of core analyses of water saturation, saturated thickness and average reservoir porosity over the connate saturated interval at different locations in the Lyons West field. These data are used to compare different possible methods for predicting regionalized compositions. The methods we consider are: 1. a direct approach for estimating compositional variables derived from the original measurements; 2. the basis method, applicable only when there is a random function that can be regarded as the size or accumulation of the regionalized variable under study; 3. the logratio approach, using the additive logratio (air) transformation. Kriging and cokriging estimation methods will be considered for original compositions and for transformed data. Software used for statistical analyses include GSLIB, programs written by Ma and Yao (2001) and ad hoc programs written by the authors. GSLIB is a public-domain library of geostatistical programs written in Fortran (Deutsch and Journel 1998); the other programs are available from their authors. The Lyons West oil field is located at 98° 15' west longitude and 38° 20' north latitude in west-central Kansas, near the center of the United States. The reservoir occurs in Mississippian (Lower Carboniferous) rocks that originated as sediments deposited in the shallow interior sea that covered much of North America in the late Paleozoic. The field was discovered somewhat accidentally in 1963, during the drilling of a deeper Ordovician prospect. Initial oil in place was estimated at 22 million stock-tank barrels of oil. The genesis of the reservoir, composed of carbonate-cemented sands, is interpreted as an offshore bar enclosed in marine shales. Regional uplift tilted the sand body, which was truncated along the western margins by the unconformity marking the base of the Pennsylvanian (Upper Carboniferous). The sandstones interfinger with marine shales to the east, but the eastern margin of the reservoir is defined by the intersection of the oil-water contact with the shale seal at the top of the reservoir interval (Ehm 1965).
Assimilation: 1900–1920
Authors: Graham Patricia Albjerg
Published: November 2020

Alively, Towheaded, Eight-Year-Old Boy shivered with dread and excitement on a cool morning in September 1900 in Ottertail County, Minnesota, as he headed for his first day of school. His older brother, Mads, and his older sister, Esther, had already attempted this venture, and neither had liked it at all. For many, not only the first day of school but latter days as well were a harrowing experience. Subsequently his six younger brothers and sisters would make the same journey, and most of them would not like it either. His father offered one piece of advice in Danish, the only language spoken in the family, “When the teacher looks at you, stand up and say, ‘My name is Victor Lincoln Albjerg.’” That was his preparation for schooling in America. His parents’ concession to his need for Americanization was his middle name; they offered few others. Victor Lincoln Albjerg was my father. Little Victor followed his father’s advice precisely, and when the teacher turned to him, he rose and replied as his father had instructed. Derisive laughter from his fellow students and a frown from the teacher greeted him. Confused and embarrassed, he sat immediately, and understood why Mads and Esther had sought to avoid school. Obviously the teacher had asked him something other than his name, but, since she spoke English and he spoke only Danish, he had no idea what she had said. The teacher, on the other hand, recognized that her preeminent task was to teach her pupils English, and to do so she forbade them from speaking their family language to each other in the school or schoolyard. The sharp rap of the birch rod met such infractions. Despite his inauspicious beginning, Victor prospered in the school, more than his father wished. Victor’s father believed in schooling only within “thrifty limits,” by which he meant a modicum of English and arithmetic and perhaps a bit else but not enough to give students an appetite for further book learning that might take them away from their local environment. As his father feared, Victor, unlike his brothers, did not want to return to the family farm. As he expressed it, “I wanted to be somebody—a rural schoolteacher.”
Achievement: 1983–Present
Authors: Graham Patricia Albjerg
Published: November 2020

Milton Goldberg Worried. As he entered the White House State Dining Room with the members of the commission that he had staffed for the previous two years, the teacher and administrator from Philadelphia pondered what the president of the United States, Ronald Reagan, would say about the report on which they had labored so vigorously. Everyone understood that most federal commission documents descend into immediate obscurity. He feared that destiny for their report. He also feared that the president would call again for policies, such as prayer in schools, vouchers for private school tuition, tuition tax credits, or abolition of the Department of Education (Goldberg’s current employer), that the commission had not endorsed. The president strode vigorously into the room as Goldberg rose anxiously. Reagan genially introduced the report, saying that it fully accorded with his earlier enunciated views on education. Obviously he had not read the report since it did not deal with any of those issues. This report was Reagan’s last major presidential effort on education, although he continued to discuss education in various speeches. The commissioners, who sought public attention for their report as a stimulus to change, feared that the press would now ignore the report, believing they had written a Reagan-support document. As one of the commissioners, physicist Gerald Holton, reported, the authors were appalled and one said loudly enough for the press to hear, “We have been had.” Hearing the remark, journalists in attendance suddenly developed an intense interest in the report. They immediately recognized a profound disconnect between the Reagan administration’s rhetoric about education and the content of the report. Both the political disconnect and the subject matter initially intrigued them, but the substance of the document caught the public’s attention and has remained there for nearly a quarter of a century. A Nation at Risk alerted the American people, often in rather colorful and occasionally purple and erroneous prose, to the danger the country faced if the academic achievement of schoolchildren did not improve.
Autonomy to Accountability
Authors: Graham Patricia Albjerg
Published: November 2020

When is Schooling Complete? At the beginning of the twentieth century most Americans believed they had “completed” their schooling if they finished the eighth grade. Only 6 percent of young people then graduated from high school. Eighth-grade graduation was a major celebration, particularly in rural neighborhoods, with the newly recognized scholars feted and dressed in their best as the photograph of my father’s 1908 Ottertail County, Minnesota, eighth-grade class illustrates. In 1955 a ninth-grade student in my homeroom, when queried how far her father had gone in school, replied confidently, “all the way.” That meant high school graduation in the Deep Creek, Virginia, neighborhood. By the end of the twentieth century, however, that definition had changed radically. “Completing schooling” now means some college at a minimum, with about 66 percent of high school graduates now attending, and increasingly it has meant acquiring a post-graduate degree. These changing expectations for what is considered sufficient schooling have dramatically altered American views of higher education. Once thought the domain of the very few (less than 2 percent of the age group in 1900) and largely peripheral to the economy, colleges and universities occupied a very different position at the beginning of the twenty-first century. They now appeal to a mass population, and they constitute a crucial link in the economy through their research and development activities. Furthermore, unlike 1900 when few foreigners would ever have considered coming to the United States to study, they now attract both students and faculty from all over the world, including some of the most gifted and ambitious. The range of these institutions from the leading research universities, which remain among the best in the world, to “open enrollment” institutions (with no requirements for admission other than paying the tuition), which provide unparalleled access to higher education, is extraordinary. Today the academic overlap between some of the best high schools and some undergraduate institutions is considerable, with high school juniors and seniors flourishing in college classes.
Plessy’s Long Shadow
Authors: Bell Derrick
Published: November 2020

The supreme court’s 1896 Decision in Plessy v. Ferguson served to bring the law into a dismal harmony with the nation’s view of race in life. The Court decided that segregation in public facilities through “separate but equal” accommodations for black citizens would satisfy the equal protection clause in the Fourteenth Amendment. The years since the sporadically enforced policies of Reconstruction ended in 1876 had been hard for those former slaves and their offspring whose slavery had legally ended with the passage of the Thir­teenth Amendment in 1865. To ensure their rights to due process and the equal protection of the law, the Fourteenth Amendment in 1868 provided that “all persons born or naturalized in the United States, . . . are citizens of the United States and of the State wherein they reside.” Despite legislation intended to provide enforcement of these rights, the laws were poorly enforced and most were subsequently declared unconstitutional. Corrupting law but relying on intimidation and violence, southern governments stripped blacks of political power. Given meaningful if unspoken assurances that the federal government would not protect black civil rights, conservative southerners regained power utilizing racial fear and hatred to break up competing populist groups of poor black and white farmers. In addition to the disenfranchisement of blacks, whites sought to secure their power through intensive anti-Negro propaganda campaigns championing white supremacy. Literary and scientific leaders published tracts and books intended to “prove” the inhumanity of the Negro. In this hostile climate, segregation laws that had made a brief appearance during Reconstruction were revived across the South, accompanied by waves of violence punctuated by an increase in lynchings and race riots. In an effort both to protest the indignity of segregation and challenge its validity, Homer Plessy, acting for a New Orleans civil rights group, attempted to ride in a railroad car reserved for whites. He was arrested and convicted of violating Louisiana’s 1890 segregation law. On appeal, the Supreme Court acknowledged that the Fourteenth Amendment required absolute equality of the two races before the law, adding: “but in the nature of things it could not have been intended to abolish distinctions based upon color, or to enforce social, as distinguished from political equality, or a commingling of the two races upon terms unsatisfactory to either.”
Molecular Informants: A Changing Perspective of Organic Chemistry
Authors: Gaines Susan M. , Eglinton Geoffrey , Rullkötter Jürgen
Published: November 2020

Lodged in the earth’s outermost layer, ephemeral scratch on a mineral skin, life plays cards with a handful of elements—builds molecular extravaganzas of carbon and hydrogen, oxygen, nitrogen, sulfur, or precious phosphorus, and forms the pieces to the parts that, assembled, define it. When the game is over, the cards reshuffled, the parts dismantled—membranes ruptured, shells dissolved, bones ground to dust—a few of those organic molecules remain in the sediments and rocks, bearing witness to the distant moments of their creation. Imagine the most humble bit of life, a microscopic alga basking in the sun-graced surface of the sea. Think of the tiny animal that grazes on the alga, dismantling its parts, using the pieces and discarding the difficult-to-digest fats and sturdy membrane lipids in tiny pellet-like feces that sink slowly into the dark waters of the deep sea—a thousand meters, two, three, maybe more. Imagine the bacteria that cling to the pellets as they settle onto the seafloor, zealous recyclers of organic molecules, using some and transforming others, leaving them stripped down or broken but still recognizable among the generic mineral bits of shell and clay that accumulate, particle by particle, year by year, layer by layer. Dig down, dig back, through meters and kilometers of sediments, through millennia and epochs, and you’ll find them yet, those molecular relics, testaments to that tiny, light-loving bit of bygone life. What do those molecules know, what do they have to say? Might they remember their maker’s name and environment, how that tiny alga lived and died? Was it rich or poor, food plentiful or scarce, the water warm or cold? Perhaps there was a current from the south, or cold nutrient-rich waters upwelling from the deep. Maybe there was a drought in Africa and dry winds blew nutrient-laden dust over the Atlantic, the continent’s misfortune a literal windfall for marine algae. Perhaps a meteor fell that year and the light went out of the sky, the temperature dropped suddenly, and the world died in a blink.
Deep Sea Mud: Biomarker Clues to Ancient Climates
Authors: Gaines Susan M. , Eglinton Geoffrey , Rullkötter Jürgen
Published: November 2020

Though the concept of the biomarker emerged from attempts to infer the provenance of petroleum and the incidence of life on the young earth—for all the successes and disappointments of the early studies on Precambrian rocks, lunar dust, and oil shales—it was in the sediments of the deep sea that biomarkers really came into their own. The Deep Sea Drilling Project (DSDP) was initiated in the 1960s by a consortium of American oceanographic research institutions, but institutions in Russia, the United Kingdom, France, and Germany were quick to sign on. In what began as an effort to understand the makeup and dynamics of the earth’s crust and mantle, the DSDP’s special research ship traveled the world’s oceans, drilling thousands of meters into the seafloor to retrieve sediment cores that soon became coveted objects of study for geologists, oceanographers, biologists, paleontologists, and geochemists around the world. When Geoff’s group started analyzing the DSDP sediments in the early 1970s, most of the organic chemists involved with the program were from the oil industry and formed part of the drill ship’s safety program, monitoring the cores as they were brought on deck to ensure that dangerous accumulations of gas or liquid hydrocarbons weren’t being penetrated. But Geoff saw the DSDP as the perfect opportunity to wean his Bristol lab of its dependence on NASA’s Apollo program—a chance to bring his full attention back to Earth and its still largely unexplored realm of fossil molecules. The British Natural Environment Research Council had earmarked a large pot of funding for work on the cores, which would be unencumbered by the narrow commercial goals and secrecy that surrounded the limited offerings from oil-company bore holes. Geoff’s budding Organic Geochemistry Unit would be aligned with a multidisciplinary community of scientists who were all studying the same cores, working cooperatively, and publishing freely. And, unlike the lunar samples, ocean sediments were rife with interesting organic compounds, including many entirely unforeseen structures. Most of the cores consisted of sediments that had been laid down and buried sequentially without ever being subjected to the tectonic turmoil of stretching and subsidence, and the overlying kilometers of cold water had kept their temperatures relatively low.
Early Life Revisited
Authors: Gaines Susan M. , Eglinton Geoffrey , Rullkötter Jürgen
Published: November 2020

That the evolution of organisms depends in large part on the evolution of their environment is something paleontologists have been noting since the early nineteenth century, and indeed, it is so inherent in Darwinian theory as to seem almost banal. That this dependency might have been two-way—that the earth’s minerals, atmosphere, oceans, and climate have been in large measure determined by the evolution of different life-forms—was somewhat harder to document and accept, partly because the most dramatic evidence was hidden, at the molecular level, in the elusive Precambrian rocks. The concept of the coevolution of Earth and life saw its first cohesive and most provocative expression when James Lovelock presented his Gaia hypothesis in the early 1970s, but not until the end of the twentieth century were the basic tenets of the hypothesis accepted as a valid theory. Lovelock began conceiving the Gaia hypothesis when he was designing instruments for NASA’s first extraterrestrial explorations and it occurred to him that, unlike the moon and Mars, the earth had an atmosphere composed of gases that couldn’t and wouldn’t coexist without life’s intervention. At the same time, a handful of paleontologists and geochemists had been conceiving similar if less provocatively formulated hypotheses based on their studies of the earth’s most ancient rocks and sediments. In 1979, a decade after Geoff, Thomas Hoering, and Keith Kvenvolden had more or less given up on the prospect of garnering clues about early life-forms from the fossil molecules in Archean and early Proterozoic rocks, one of those paleontologists inadvertently inspired a certain Australian chemist to give it another go. Roger Summons met the paleontologist Preston Cloud when Cloud was on sabbatical at the Australian Institute of Marine Science. Summons was working in the biology department at Australian National University and had been assigned to play guide and chauffeur for Andrew Benson, a visiting American plant physiologist who was staying out at the marine institute. “There was a couple living in the guesthouse next to us,” Summons tells me. “And this guy was a jogger. He’d leave every morning at 5:00 A.M. and run past the house, clump clump clump clump, and I’d wake up.”
The Classification of Intellectual Disability
Authors: Harris James C.
Published: November 2020

Although intellectual disability has been recognized since antiquity, interest in its classification did not develop until the nineteenth century, when it became apparent that intellectual disability is not one homogeneous category, as was previously thought, but has many causes. Moreover, it became apparent that intervention could be beneficial and that interventions might be tailored for specific disorders. Early authors prepared the way for modern efforts to differentiate specific conditions that differ in both etiology and pathology, yet all result in intellectual disability. Some attempts were misguided. J. Langdon Hayden Down, in his ethnic classification (1866; Jordan, 2000), sought to classify based on the physical appearance of the individuals he examined. His goal was to absolve parents of self-blame for the handicap by emphasizing a constitutional basis for their child’s disorder. He proposed an “ethnic classification,” suggesting that the various forms of intellectual disability represented regressions to stereotypical racial forms (e.g., mongoloid, Aztec). Although he later abandoned this unfortunate idea, he continues to be known for it. Still, he is credited with drawing scientific attention to the syndrome bearing his name (Jordan, 2000) and for suggesting that the best classification is one based on etiology. Subsequently, he anticipated current efforts at classification by describing three major groups: (1) congenital, which included microcephalic, macrocephalic, hydrocephalic, epileptic, and paralytic types; (2) developmental, with a vulnerability to mental breakdown with stress during a developmental crisis; and (3) accidental (caused by injury or illness). Later, William Weatherspoon Ireland (1877), in his textbook on intellectual disability, suggested 10 subdivisions. Among these are genetous (congential), microcephalic, epileptic, eclamptic, hydrocephalic, paralytic, traumatic, inflammatory, cretinism, and idiocy by social and physical deprivation. In 1880, tuberous sclerosis complex was identified by Désiré-Maglione Bourneville (1880), who established that intellectual disability might result from brain pathology. Subsequently, many other intellectual disability syndromes were recognized. Thus began a new era, with investigators searching for clearly defined disorders associated with intellectual disability; these were commonly named after their discoverers. It was an era when intellectual disability syndromes were beginning to be recognized, but medicine had little to offer therapeutically.
Rules to Work By
Authors: Bauder Harald
Published: November 2020

“Culture shock” is a common phenomenon among visitors to another country, and even the most seasoned traveler can be stymied by local behavioral norms, cultural conventions, and values. Tourists often revel in the sensation of being surrounded by the exotic and unknown. Other visitors, such as foreign exchange students, face a greater challenge as they attempt to forge relationships with native classmates and host families while learning a new language. Immigrants also face a challenge of cultural adaptation when they arrive in their new country, but they have much more at stake than the casual tourist or exchange student. Although the shock experience fades in most cases, immigrants often continue to experience difficulties reconciling the dominating cultural norms and conventions of their new home with their own norms and values. That is, the habitus of the newcomer does not match local norms and expectations. The rules of the game are defined locally, and the stranger who is unfamiliar with the rules will be unable to play effectively or will be excluded from the game altogether. Labor markets and business networks also operate according to a set of rules. For immigrants, being unfamiliar with these rules can have profound effects. For example, many Chinese business-class immigrants who came to Canada as entrepreneurs quickly discovered that the business world operates differently in Vancouver than in Hong Kong or Taipei. Many of their businesses folded and their investments flopped because they were unprepared for stringent regulations, strange business practices, and peculiar consumer behavior (Ley 1999, 2003). Consequently, a large number of Chinese immigrant entrepreneurs reoriented their investments back to China, where they knew how to run a business profitably. The return of Chinese entrepreneurs to East Asia is one of the reasons the astronaut family is a common phenomenon in Vancouver. Business regulations and conventions rendered Canada an unattractive place for investment by many Chinese immigrant entrepreneurs. In the labor market, conventions and norms are equally important. Many immigrants are unfamiliar with the norms and conventions of the hiring process in Canada, are unable to judge employers’ expectations, and are unaware of the codes of conduct in the Canadian workplace.
Rheology of Liquid-Crystalline Polymers
Authors: Han Chang Dae
Published: November 2020

Liquid crystals (LCs) may be divided into two subgroups: (1) lyotropic LCs, formed by mixing rigid rodlike molecules with a solvent, and (2) thermotropic LCs, formed by heating. One finds in the literature such terms as mesomorphs, mesoforms, mesomorphic states, and anisotropic liquids. The molecules in LCs have an orderly arrangement, and different orders of structures (nematic, smectic, or cholesteric structure) have been observed, as schematically shown in Figure 9.1. The kinds of molecules that form LCs generally possess certain common molecular features. The structural characteristics that determine the type of mesomorphism exhibited by various molecules have been reviewed. At present, our understanding of polymeric liquid crystals, often referred to as liquid-crystalline polymers (LCPs), is largely derived from studies of monomeric liquid crystals. However, LCPs may exhibit intrinsic differences from their monomeric counterparts because of the concatenation of monomers to form the chainlike macromolecules. The linkage of monomers inevitably means a loss of their translational and orientational independence, which in turn profoundly affects the dynamics of polymers in the liquid state. These intramolecular structural constraints are expressed in the flexibility of the polymer chain. Generally speaking, the chemical constitution of the monomer determines the flexibility and equilibrium dimensions of the polymer chain (Gray 1962). Figure 9.2 illustrates the variability of chain conformation (flexible chain, semiflexible chain, and rigid rodlike chain) forming macromolecules. Across this spectrum of chain flexibility, the persistence in the orientation of successive monomer units varies from the extreme of random orientation (flexible chains) to perfect order (the rigid rod). Hence, efforts have been made to synthesize LCPs that consist of rigid segments contributing to the formation of a mesophase and flexible segments contributing to the mobility of the entire macromolecule in the liquid state (Ober et al. 1984). From the point of view of molecular architecture, as schematically shown in Figure 9.3, two types of LCP have been developed: (1) main-chain LCPs (MCLCPs), having the monomeric liquid crystals (i.e., mesogenic group) in the main chain of flexible links, and (2) side-chain LCPs (SCLCPs), having the monomeric liquid crystals attached, as a pendent side chain, to the main chain.
Compression Molding of Thermoset/Fiber Composites
Authors: Han Chang Dae
Published: November 2020

Glass-fiber-reinforced thermoset composites have long been used by the plastics industry. Two primary reasons for using glass fibers as reinforcement of thermosets are: (1) to improve the mechanical/physical properties (e.g., tensile modulus, dimensional stability, fatigue endurance, deformation under load, hardness, or abrasion resistance) of the thermosets, and (2) to reduce the cost of production by replacing expensive resins with inexpensive glass fibers. In place of metals, the automotive industry uses glassfiber- reinforced unsaturated polyester composites. One reason for this substitution is that the weight per unit volume of composite materials is quite low compared with that of metals. This has allowed for considerable reductions in the fuel consumption of automobiles. Another reason is that composite materials are less expensive than metals. The unsaturated polyester premix molding compounds in commercial use are supplied as sheet molding compound (SMC), bulk molding compound (BMC), or thick molding compound (TMC) (Bruins 1976; Parkyn et al. 1967). These molding compounds can be molded in standard compression or transfer molds. The basic challenge in molding unsaturated polyester premix compounds is to get a uniform layer of glass reinforcement in place in the die cavity while the resin fills the cavity and reaches its gel stage during cure. Temperature, mold closing speed, pressure, and cure time are all functions of the design of the part being produced. The flow of the mixture through the gate(s) can result in variations in strength across the part due to fiber orientation during the flow. The precise end-use properties depend on the fiber orientation, fiber distribution, and fiber content in the premix compounds, which are greatly influenced by the processing conditions. Since the mechanical properties of the molded articles depend strongly upon the orientation of the glass fibers, it is important to understand how to control fiber orientation during molding. Unsaturated polyester accounts for the greater part of all thermosets used in glass-fiber-reinforced plastics. Glass-fiber-reinforced unsaturated polyesters offer the advantages of a balance of good mechanical, chemical, and electrical properties. Depending upon the application, a number of additives are employed to provide specific products or end-use properties.