bluuebunny/crossref_metadata_2025 huggingface dataset:
Climate Discourse Transformed
Authors: Fleming James R.
Published: November 2020

The impressionistic Enlightenment view of the American climate and its changes was rebutted in two distinct ways—literary and scientific. The literary critique was spearheaded by Noah Webster in 1799 and finally put to rest four decades later by Samuel Forry, a surgeon and climatologist in the United States Army. The scientific response came from pioneer climatologists who subjected the growing amounts of meteorological data to statistical analysis. Both approaches contributed to the radical transformation of climate discourse and, along with the expansion of meteorological networks, led to the emergence of a recognizably modern climatology. In his essay “On the Supposed Change in the Temperature of Winter,” Noah Webster criticized the “popular opinion” advanced by “many writers of reputation . . . the Abbé Du Bos, Buffon, Hume, Gibbon, Jefferson, Holyoke, Williams” that the climate of Europe and America, especially the temperature of winter, had become warmer in modern times. His critique emphasized their loose citation of sources, both ancient and contemporary, and the improper deductions they drew from these citations: . . . Men are led into numberless errors by drawing general conclusions from particular facts. “Lady Montague sat with her window open in January, 1718, and therefore there is little or no winter in Constantinople,” is very bad logic. The farmers on Connecticut River plowed their lands, as I saw in February, 1779; and the peaches blossomed in Pennsylvania. What then? Are the winters all mild in America? Not at all; in the very next year, not only our rivers, but our bays, and the ocean itself, on our coast, were fast bound with ice. . . . Webster was particularly critical of Samuel Williams, whose contention that Italy had warmed seventeen degrees in eighteen centuries was based on selective citations from ancient Roman writers. Williams erred in his assumption that reports of extreme weather were representative of ordinary conditions. Webster used historical accounts of the range of frost-sensitive plants—olive, fig, and date trees—to argue that Italy’s climate had not changed since antiquity and “could never have been colder than the Carolinas” and that its winters “were not severe, but mild.”
T. C. Chamberlin and the Geological Agency of the Atmosphere
Authors: Fleming James R.
Published: November 2020

The earth sciences may have experienced their most recent conceptual revolution in the 1970s with the acceptance of plate tectonics, but that was by no means their only major revolution. T. C. Chamberlin (1843–1928), America’s most eminent geologist turned geocosmologist, experienced three major conceptual revolutions in his field. As a student in the 1860s, he rejected the scriptural geology he had learned in his youth. As a working geologist interested in multiple glaciations, he rejected the dominant theories of hot planetary birth and secular cooling of the Earth as severely lacking in explanatory power. As one of the leading interdisciplinary scientists of his day, he formulated a new theory of the origin and evolution of the Earth and solar system—the planetesimal hypothesis. Glacial theories of the late nineteenth and early twentieth centuries appear in three distinct clusters: astronomical theories involve changes in the Sun’s luminosity, the passage of the Earth through opaque regions of space, and the variation of the Earth’s tilt and orbital elements; terrestrial theories include mountain building, volcanism, and changes in atmospheric and oceanic circulations; and molecular theories invoke changes in the water vapor or CO2 content of the atmosphere. The favorite among geologists was Charles Lyell’s theory of continental uplift and mountain building. James Croll’s theory of periodic changes in solar insolation due to changes in the Earth’s orbital elements was tantalizing but did not fit with geological evidence. Speculations about possible changes in the Sun were popular as well but were impossible to prove. Lord Kelvin had decided that the Sun was simply cooling off and the Earth’s future climate would be a cold, frozen one. Most theorists focused on a single mechanism of glaciation, with perhaps a secondary cause added in. There was some lip service to but little interest in multiple causation. Chamberlin tried to keep his options open by advocating his “method of multiple working hypotheses.” He was one of the first geologists to see the Ice Age as a series of multiple glaciations, and he was interested in searching for fundamental mechanisms of change that would explain the details, including the repeated oscillations between cold and warm epochs, the timing and duration of these events, and the differences between high and low latitude glaciation.
Global Warming? The Early Twentieth Century
Authors: Fleming James R.
Published: November 2020

In the first half of the twentieth century, most scientists did not believe that increased CO2 levels would result in global warming. It was thought that at current atmospheric concentrations, the gas already absorbed all the available long-wave radiation; thus any increases in CO2 would not change the radiative heat balance of the planet but might augment plant growth. Other mechanisms of climatic change, although highly speculative, were given more credence, especially changes in solar luminosity, atmospheric transparency, and the Earth’s orbital elements. By the 1950s, as temperatures around the Northern Hemisphere reached early-twentieth-century peaks, global warming first found its way onto the public agenda. Concerns were expressed in both the scientific and popular press about rising sea levels, loss of habitat, and shifting agricultural zones. Amid the myriad mechanisms that could possibly account for climatic changes, several scientists, notably G. S. Callendar, Gilbert Plass, Hans Suess, and Roger Revelle, focused on possible links between anthropogenic CO2 emissions, the geochemical carbon cycle, and climate warming. By 1900, most of the chief theories of climate change had been proposed, if not yet fully explored: changes in solar output; changes in the Earth’s orbital geometry; changes in terrestrial geography, including the form and height of continents and the circulation of the oceans; and changes in atmospheric transparency and composition, in part due to human activities. Of course, there were many others. New climate theories were being proposed and new work was being done on heat budgets, spectroscopy, and the rising CO2 content of the atmosphere. Evidence for glaciation in low latitudes was explained by Wladimir Köppen and Alfred Wegener as the result of continents drifting northward under climate zones controlled mainly by latitude. Although this theory was not widely accepted by geologists, it is now seen as a first step in paleoclimatic reconstruction. In the 1930s, the Serbian astronomer and geophysicist Milutin Milanković, building on earlier work, outlined a comprehensive “astronomical theory of the ice ages” that viewed them as caused by periodic changes in the Earth’s orbital elements. Atmospheric heat budgets were constructed early in the twentieth century by William Henry Dines and George Clark Simpson, among others.
Global Cooling, Global Warming: Historical Dimensions
Authors: Fleming James R.
Published: November 2020

I have chosen to conclude these essays just as the well-known IGY was getting started. Of course, much has changed since then. There is little to gain, however, by attempting to recount the recent policy history of global change, at least from my perspective as a historian of science and technology. I have tried in this book to provide fresh perspectives on the more distant past, not to replicate the recent literature on global change. Although I am actively engaged in projects sponsored by the American Meteorological Society and the American Geophysical Union that document the recent past, I have little inclination to attempt to interpret it. Consequently I include in this chapter only the briefest sketch of the global cooling scare after 1958 and the return of a global warming discourse in the 1980s. I believe the metaphor of apprehension (awareness, understanding, fear, intervention) applies quite well to a number of current environmental issues, and I will point to some of them by way of conclusion. I was asked once after a seminar whether, as a historian, I could predict the eventual demise of today’s global change discourse, since there had been so many changes in the past. I responded that history has no predictive value, but does indeed provide valuable perspectives to its readers. History is first and foremost the study of change. For students of global change, history can serve as an inspirational story of how far we have come. It can also serve as a humbling reminder that change is indeed inevitable in our lives, in the Earth system, and in our ideas and institutions. Although I am professionally engaged with the past, I am still a citizen of my own age—an age of vastly enhanced environmental awareness. Like many of my contemporaries, I believe that humanity is a part of, not apart from, nature; that human activity is placing tremendous stress on global biophysical systems; and that we have an ethical responsibility to each other and to future generations to live sustainably, in harmony with the Earth. Your guesses about the future are probably as good as and perhaps better than mine.
Reflection and Refraction of Waves at a Planar Composite Interface
Authors: Chimenti Dale , Rokhlin Stanislav , Nagy Peter
Published: November 2020

Nondestructive ultrasonic testing of composite materials is affected by several special features of wave propagation that arise from the strong anisotropy and inhomogeneity of these materials. The resulting complexity requires re-examination of old testing methodologies and development of new ones. One of the most fundamental phenomena in ultrasonic nondestructive evaluation is the reflection–refraction of ultrasonic waves at a plane interface. Even the simplest test procedure requires understanding of mode conversion and knowledge of elastic wave reflection and transmission coefficients and refraction angles. Reflection–refraction phenomena, while straightforward and well documented for isotropic materials, are much more complicated for anisotropic materials. When analyzing the oblique incidence inspection method for composite materials, one first has to address the problem of wave propagation through the interface between the coupling medium and the composite material. For example, there is an inherent fluid/composite interface in the immersion technique and a perspex/composite interface in the contact method. In the latter case, assuming that a thin fluid layer is applied to facilitate coupling through the interface, slip rather than welded boundary conditions prevail. Another example of great practical importance is the case of multidirectional fiber plies in a composite laminate, when the reflection and transmission of ultrasonic waves from one ply to another with a different orientation must be considered. Before discussing the general problem of wave refraction in anisotropic composite materials, let us review the simple isotropic case. Consider a plane interface between two isotropic elastic media in “welded” (perfectly bonded) contact, implying continuity of tractions and displacements across the interface, although the boundary conditions are not important at this point. Figure 4.1 shows a schematic diagram of a plane wave with wavenumber ki incident on the interface at angle θi. The parallel lines with spacing equal to the incident wavelength λi correspond to equal-phase planes orthogonal to the incident plane. By definition, the wavenumber ki = 2π/λi is the magnitude of the wave vector ki. The incident wave is converted at the interface into reflected and transmitted waves. The refraction angle of the transmitted wave is θr and its wavenumber is kr.
Selected Topics in Approximation and Computation
Authors: Kowalski Marek A. , Sikorski Krzystof A. , Stenger Frank
Published: November 2020

Selected Topics in Approximation and Computation addresses the relationship between modern approximation theory and computational methods. The text is a combination of expositions of basic classical methods of approximation leading to popular splines and new explicit tools of computation, including Sinc methods, elliptic function methods, and positive operator approximation methods. It also provides an excellent summary of worst case analysis in information based complexity. It relates optimal computational methods with the theory of s-numbers and n-widths. It can serve as a text for senior-graduate courses in computer science and applied mathematics, and also as a reference for professionals.
Summary of Elements of Algebraic Theory
Authors: Iachello F. , Levine R. D.
Published: November 2020

Algebraic theory makes use of an algebraic structure. The structure appropriate to ordinary quantum mechanical problems is that of a Lie algebra. We begin this chapter with a brief review of the essential concepts of Lie algebras. The binary operation (“multiplication”) in the Lie algebra is that of taking the commutator. As usual, we denote the commutator by square brackets, [A, B] = AB - BA. A set of operators {X} is a Lie algebra when it is closed under commutation.
Generative Sets and Creative Systems
Authors: Smullyan Raymond M
Published: November 2020

we now have the background to study the beautiful subject of creative and productive sets inaugurated by Emil Post [1944]. This plays a key rôle in the metamathematical study of incompleteness and undecidability. §1. Productive and Creative Sets. To say that a set A is not r.e. is equivalent to saying that for any r.e. subset ωi of A, there is a number in A not in ωi . A is called productive if there is a recursive function f(x)—called a productive function for A—such that for any number i, if ωi Í A, then f(i) Î A - ωi . [Informally, this means that it is not only true that no r.e. subset of A is A, but given any such r.e. subset, we can effectively find a number which is in A but not in the subset.] A set A is called creative (after Post) if it is r.e., and its complement is productive. Let us note that a productive function for the complement of a set A is a recursive function f(x) such that for any number i such that ωi is disjoint from A, the number f(i) lies outside both ωi and A. A system S is called productive if the set P of Gödel numbers of the provable formulas of S is a productive set; S is called creative if the set P is creative. As we will see, the complete theory N is not only not axiomatizable but is productive, and the system P.A. is not only undecidable but creative. Post’s Sets C and K. A simple example of a creative set is Post’s set C —the set of all numbers x such that x Î ωx. Thus for any number i, i Î C ↔ i Î ωi. If ωi is disjoint from C, then i is outside both ωi and C and, therefore, the identity function I(x) is a productive function for C͂. Therefore, C͂ is productive, and since C is obviously r.e., C is creative.
Classical Theories of Rubber Elasticity
Authors: Erman Burak , Mark James E.
Published: November 2020

This chapter describes three molecular theories of rubber elasticity. Section 2.1 outlines the elementary theory of Kuhn and Treloar, which is of particular importance since it presents the basic elements of rubberlike elasticity in a very transparent way. Section 2.2 presents the phantom network model developed by James and Guth, and section 2.3 presents the affine network model developed by Wall and Flory. Historical aspects of the theories have been given in an article by Guth and Mark, and in a book prepared as a memorial to Guth. Finally, the major features of both theories are briefly summarized in a review. Separately, the James-Guth theory has been reviewed by Guth and by Flory, and the phantom network model of section 2.2 is based on the Flory treatment. The affine network model has been described in detail in Flory’s 1953 book. This model is described in section 2.3 by generalizing the phantom network model (as was done in one of Flory’s subsequent studies). The simple, elementary statistical theory described in section 2.1 paved the way to the current understanding of rubber elasticity. Further progress in the understanding of rubberlike systems was possible, however, only as a result of the two more precise and accurate theories: the phantom network and the affine network theories. Despite their differences, these two theories and the corresponding molecular models have served as basic reference points in this area for more than four decades. They still serve this purpose for the interpretation and explanation of experimental data. The differences between the assumptions and the predictions of the two models have led to serious disagreements during their development, as may be seen from the original papers cited earlier. The main point of disagreement was the magnitude of the front factor that appeared in the expression for the elastic free energy and the stress. For tetrafunctional networks, the James-Guth phantom network theory predicts one-half the value of the front factor obtained by the Wall-Flory affine network theory.
Ecology, Phenotype, and Character Evolution in Bluegill Sunfish: A Population Comparative Approach
Authors: Ehlinger Timothy J.
Published: November 2020

Evolutionary ecology explores the intimate relationships between the mechanisms responsible for the production and maintenance of organismal form and the ecological function of the structures and behaviors that compose form (Arnold 1983). The analysis of diversity from this perspective is founded on the premise that variation in measured phenotypes can reflect the results of the process of natural selection (Williams 1966, 1992; Gould and Vrba 1982). However, because the fitness consequences of any particular phenotype are the result of complex interactions among an individual’s genotype, morphology, behavior, and the environment within which it must function (Gould and Lewontin 1978, Endler 1986), a phenotype best suited for one set of environmental conditions may not perform best in another (e.g., Endler 1983, Rausher 1984, Ehlinger and Wilson 1988, Schluter 1993). When making comparisons among populations, phenotypic variation due to underlying genetic differences that may reflect evolutionary responses to different environments must be distinguished from phenotypic variation that results from phenotypic plasticity and/or genotype–environment interactions (Stearns 1989). For example, regional environmental variation can result in different selective regimes among populations and produce “site-dependent” fitnesses for phenotypes (e.g., Reznick et al. 1990, Robinson and Wilson 1994; chapters in this volume). Likewise, varying social and trophic conditions on a local scale can result in “situation-dependent” performances and payoffs for different phenotypes within populations (Maynard-Smith 1974, Ehlinger 1990, Krebs and Kacelnik 1991). Both phenomena may influence patterns of geographic variation and must be considered when studying phenotypic differences among populations. My aim in this chapter is to illustrate how population comparisons of bluegill sunfish (Lepomis macrochirus) can be used to study the evolution of behavioural and morphological variation. Critical features that shape bluegill trophic ecology (e.g., temperature, depth, substrate type, prey types, productivity, and predator abundance) vary among lakes in combination with forces that influence reproductive ecology (e.g., availability of spawning habitat and age or size structure of the population). Population comparisons provide unique opportunities for discerning the roles of sexual and trophic selection in bluegill phenotypic evolution.
Social Shaping of Technology
Authors: Salzman Harold , Rosenthal Stephen R.
Published: November 2020

Artists leave behind their names on their work and, with their face and story, provide some insight into the design of their creations. Not so with workplace technology. The design of technology often appears as received wisdom. A band of technicians descends upon an office or a factory floor leaving behind artifacts bearing the labels of companies whose names are familiar but whose identities are really anonymous. In some abstract way we all know that inanimate objects are manufactured, the product of human design. Yet, as we handle and look at these artifacts we use everyday, we seldom know the whys and wherefores of their design. We may judge the technology as easy or difficult to use, helpful or unhelpful in accomplishing the task at hand, and regard it as good or bad. But the calculus that went into the design decisions almost always remains a mystery. If we inquire of the designers of a piece of technology, by which we mean those who engineered and made decisions about its features and functionality (decisions beyond its aesthetic appearance, which is a common connotation of design but too limited for our purposes), we are likely to be mesmerized by formulae, calculations, reports of the latest discoveries of science and state-of-the-art engineering. In short, we may be informed that “economy and efficiency” (with perhaps a bit of aesthetics thrown in) are the watchwords of engineering. Engineering is portrayed as an objective enterprise limited only by knowledge and creativity. Many would argue that, provided a task that is well defined and a mission to accomplish, the engineer can proceed to create the optimal technology. To the social scientist these explanations generally form an impenetrable wall that precludes further inquiry. Although the social impact of technology has been widely studied, technology itself is usually treated as a “black box.” Research instead tends to focus on what to do with the black box, how to implement it, not how to create it. Thus social scientists have contributed little (and are seen as offering little) to the task of technology design, except in such realms as human factors for the user interface, a contribution viewed as rather peripheral to the “real” task of engineering.
Understanding and Managing Software Acquisition
Authors: Salzman Harold , Rosenthal Stephen R.
Published: November 2020

In today’s service-oriented economy, information systems are becoming the lifeblood of many organizations. As part of this trend, applications software is an increasingly important and little understood type of process technology. In this chapter we synthesize many of our findings and explore their implications for procuring software in organizations that deliver services. We will argue that it is during the procurement of software and in the planning processes that precede procurement that managers with insight about software design have the most to offer. This book has provided several extended examples of how mission critical software is used in service organizations by operational personnel to assist them in service delivery and by management for monitoring and control purposes. We have shown how service delivery becomes redefined in terms of the combined capability of workers and the integrative functionality designed into mission critical software. We have also shown how software may affect the structure of a service organization and the scope of individual jobs within it. Mission critical software thus serves important integrative functions, such as job restructuring and service redefinition, for the service delivery organization. Although vital to any company’s production capability, process technology is often viewed as an ancillary concern of top management when it comes to purchasing it. Procurement is thought to be best left to technicians who have both the time and inclination to preoccupy themselves with comparison shopping. Many managers are uncomfortable with technological decisions. In large organizations, decisions about new technology tend to be delegated to groups far removed from senior management. Only when procurement costs rise above a certain threshold will the level for such decisions be escalated in the organization. By then, assessments are usually reduced to some sort of financial payback calculation and the substantive issues associated with the proposed technology become submerged. The crucial shortcoming of this approach is that technology acquisition is an important strategic issue, not just a technical matter. By shaping the capabilities of the organization’s production function, process technologies, can dramatically affect productivity, quality, and the range of possibilities for making goods or delivering services.
The Teardrop Magnetosphere
Authors: Kennel Charles F.
Published: November 2020

In this chapter, we try to infer from magnetohydrodynamic reasoning and observation how the magnetosphere might look and behave if the magnetopause were inactive. Since there probably never has been an occasion when both viscosity and reconnection were absent, all we can do is array observations of phenomena that do not depend on either mechanism for their existence. As a result, we end up focusing on how the magnetosphere arrives at a balance of pressure with the solar wind. How it responds to changes in its confining pressure will be the topic of the next chapter. All discussions of the magnetosphere start with the magnetopause, and, indeed, the first models of the magnetosphere were calculations of the shape of the magnetopause. Without reconnection and without viscosity, the magnetopause would be given by the Chapman-Ferraro model on the dayside and close due to the reexpansion of the finite-temperature solar wind on the nightside (Section 2.2). This magnetosphere has a teardrop shape. After the dependence upon the interplanetary field via the reconnection process is taken into account, the average position and shape of the dayside magnetopause is in general accord with the Chapman-Ferraro model (Section 2.3). Because the magnetopause is always in motion, the early estimates of its thickness were uncertain until the first twospacecraft observations were made (Section 2.4). The magnetopause current layer proved to be several ion Larmor radii thick, significantly thicker than the electron inertial length. Once the average position of the magnetopause is specified, the position of the bow shock can be calculated using methods first employed for hypersonic flow around blunt bodies, which are easily extended to a weak-field MHD regime. The measured average positions of the bow shock and magnetopause agree once variations in solar wind dynamic pressure are taken into account (Section 2.5). While weak-field MHD does a good job with the bow shock, it fails in the subsolar magnetosheath, where a plasma depletion layer forms just upstream of the magnetopause (Section 2.6). Full MHD theory suggests that as many as three shocks could be standing in the flow enclosing the magnetosphere, a fast bow shock, an intermediate shock, and a slow shock.
The Reconnecting Magnetosphere
Authors: Kennel Charles F.
Published: November 2020

Dungey’s (1961a) pattern of internal magnetospheric convection was similar to that of Axford and Hines (1961). However, his model made testable statements about the structure of the magnetosphere that were not contained in the viscous convection model. It predicted that solar wind plasma enters the magnetosphere over the polar caps, that open field lines connect the polar caps directly to the interplanetary magnetic field, and that these field lines are stretched into a long, low-density magnetic tail. There would be a current layer separating the two lobes of the tail, and surrounding it, a sheet of relatively dense, hot, earthward-convecting plasma confined by closed field lines. A second magnetic neutral line would terminate the earthward flow region (Levy et al., 1964; Axford et al., 1965; Petschek, 1966; Axford, 1969). To preserve the steady state, reconnection at the tail neutral line had to have the same rate as at the dayside magnetopause. Clearly, the two reconnection regions ought to be major drivers of magnetospheric activity. Yet unambiguous proof of the existence of magnetopause reconnection was not found until 1979, 18 years after the reconnection model was proposed, and no one knew where to look for tail reconnection, because Dungey’s model did not say how far away the tail neutral line was. However, the closure of the slow expansion fans carrying solar wind plasma into the tail lobes was a natural way to force tail reconnection (Coroniti and Kennel, 1979). This closure point is fifty to one hundred earth radii downstream of earth. Twenty-four years were to pass before the average location of the tail neutral line could be established, because no spacecraft until ISEE-3 spent enough time that far downtail. In retrospect, it is a testament to the power of the paradigm that so many would search for so long for direct evidence of dayside and nightside reconnection without jettisoning Dungey’s model altogether. Faith in Dungey’s model was sustained by its collateral predictions. The access of energetic particles of solar origin to the polar cap ionosphere confirmed that reconnection occurs.
Coordination Of The Geosynchronous And Auroral Substorms
Authors: Kennel Charles F.
Published: November 2020

Studies using data from the ATS-5 geosynchronous spacecraft revealed a clear relationship between midnight region injection events near the spacecraft and auroral displays near the ATS magnetic conjugate point (Hones et al., 1971a; Mende et al., 1972; Eather et al., 1976; Mende and Shelley, 1976). A comparison of ATS-5 particle and magnetic field data with all-sky photographs taken at the conjugate point, Great Whale River, indicated that an injection at geostationary orbit generally corresponded to the brightening of the onset arc when the spacecraft was in the midnight sector (Akasofu et al., 1974). Results such as this whetted the collective appetite. How closely can the initial onset and injection be related to one another in time, do the onset and injection start on the same field field line, does the westward propagation of dipolarization correspond to the westward surge, can one relate the fine structures of the auroral expansion and the dipolarization? As time passed, increasingly precise answers have been given to these and similar questions, and auroral and geosynchronous substorm phenomenology has become more tightly integrated. In this chapter, we sample some of the evidence that supports this statement. The GEOS 2 spacecraft was stationed with its magnetic conjugate point near Kiruna, Sweden, so that the conjugate aurora could be studied with the extensive network of ground-based observatories in Scandinavia (Knott, 1975; Knott et al., 1979). In the first part of this chapter, we review some of the correlation studies carried out in the GEOS 2 project. In one particular series of four substorms, it was found that the dipolarization occurred at the same time as the aurora brightened and expanded poleward over the ground conjugate region (Section 14.2). In another case, a dispersionless injection at GEOS 2 corresponded to an intensification of the auroral X-ray band in Scandinavia (Section 14.2). Westward surges at the auroral conjugate point were associated with dipolarization at the spacecraft on a statistical basis (Section 14.3). Finally, the close relationship between both the auroral and geostationary substorm phenomena was extended to small spatio-temporal scales.
Geographic Information Systems and Spatial Analysis in the Social Sciences
Authors: Goodchild Michael F.
Published: November 2020

Although geographers have used them for centuries, the idea that they might be part of the formal or informal process of data analysis and scientific inference is still novel in many areas of the social sciences. In economics, for example, the dominant paradigm emphasizes search for theories and principles that apply uniformly within human society or its economies, and if geographic areas such as nation-states are used as units of analysis, their role is more or less that of statistical samples, each equally representative of a hypothetical population of all possible nation-states. Within this paradigm (and I do not wish to suggest that it is the only paradigm within economics or that it is necessarily inappropriate), a list of nation-states, ordered alphabetically, is more precise and useful for analysis than a map, since maps tend to lump data values into coarse classes of color or shade and make it difficult to identify the attributes of small nation-states like Luxembourg or St. Lucia. Tables, on the other hand, present each nation state’s value clearly and precisely. The chapters in this book represent a striking departure from this orthodoxy, since each describes research that depends in some way on a belief in the importance of spatial context or in looking at data from a spatial perspective. This might mean merely looking at a map, despite the disadvantages already noted. Or it might mean direct reference to such primitive spatial concepts as adjacency, proximity, direction, or coincidence in space. We might choose to call this examination of data in spatial context GIS or spatial analysis, and the methods used might be mathematically sophisticated, computationally intensive, or simply intuitive—the chapters in this book cover a wide range of options. Taken together, however, it is clear that they represent a striking departure from the aspatial ways of thinking described earlier. It seems appropriate in this concluding chapter to attempt a summary of the main features and assumptions of spatial analysis and its limitations and impediments. One of the aims of GIS is to make spatial analysis easier, more flexible, and more powerful.
Closing Remarks
Authors: Greenlaw Raymond , Hoover H. James , Ruzzo Walter L.
Published: November 2020

The previous chapters have laid out the history, foundations, and mechanics of the theory of P-completeness. We have shown that this theory plays roughly the same role in the parallel complexity domain as , NP-completeness does in the sequential domain. Having devoted much effort to establishing the notion of feasible highly parallel algorithms and arguing that P-completeness captures the notions of inherently sequential problems and algorithms, it is now appropriate to temper our case a bit with some additional observations. For some problems depending on the relevant input size, it may not be worth the effort to search for a feasible highly parallel algorithm assuming for example that you already have a √n time parallel algorithm. The following table shows the relationship between square roots and logarithms for various input sizes. Of course, for small input sizes the constants on the running times also play a major role. Although it is extremely risky to predict hardware trends, it seems safe to say that massively parallel computers containing billions of processors are not "just around the corner" and although potentially feasible, machines with millions of processors are not soon to become commodity personal computers. Thus, highly parallel algorithms will not be feasible if the processor requirements for an input of size n are much greater than n2, and probably more like n log n. Even if you have sufficient numbers of processors for problems that interest you, your algorithm may succumb to the tyranny of asymptotics. For example, a parallel algorithm that uses √n time is probably preferable to one that uses (logn)4 time, at least for values of n less than 1013. As Table 11.1 illustrates, the only really practical polylogarithmic parallel time algorithms are O((logn)2). Perhaps the limit to feasible highly parallel algorithms are those that run in (logn)2 time and use O(n2) processors. However, the search for an NC algorithm often leads to new insights into how a problem can be effectively parallelized. That is, a problem frequently is found to exhibit unexpected parallelism when the limits of its parallelism are pushed.
Principal Component Analysis Of Three -Way Data
Authors: Hohn Michael Edward
Published: November 2020

Extension of conventional eigenvector analysis to three-way sets of data is possible through three-mode principal component analysis. First introduced in the 1960's, this method gives three sets of loadings corresponding to the three ways in the data, e.g., variable, location, and time. A core matrix relates loadings across modes. Data must be centered and scaled before analysis, and as in conventional two-way analysis, preprocessing options affect the reduction in dimensionality and the appearance of the results. An example using water quality data illustrates the method and preprocessing effects. Although three-way tables can be studied through conventional analysis of a two-way table created by combining two modes of the data, three-mode analysis treats each mode separately and with the same weight. In addition, a restricted three-mode principal component model avoids problems in rotational indeterminacy, and results in a particularly simple model. Factor analysis or principal component analysis begins with a two-way table with samples along one margin and variables along the other. For instance, samples may be arranged as rows and variables as columns. R-mode analysis of the columns displays interdependencies among variables and Q-mode analysis displays similarities among samples. The analysis increases in complexity if a set of variables is repeatedly observed on the same samples; each set of measurements might represent a different experimental condition, chemical or sedimentological fraction, or simply geologic time. The resulting table of data can be visualized as a three-dimensional block: horizontal slices represent samples, vertical slices parallel with the front represent variables, and vertical slices parallel with the ends represent different conditions, times, or fractions. For example, Oudin (1970) performed elemental analyses of organic extracts from Jurassic shales in the Paris basin. Samples represented very different depths of maximum burial. Each was fractionated into several extracts according to solubility in organic solvents. Data published by Oudin (1970) have the three ways: locality, fraction, and element. Multivariate analysis of these data was presented by Hohn (1979). Hohn and Friberg (1979) applied principal component analysis to petrographic data in which the three modes were sample, mineral phase, and chemical component.
Expert Systems In Environmental Geology
Authors: Skala W. , Heynisch S.
Published: November 2020

Geoscientific environmental research deals with very complex problems requiring integration of knowledge from many different fields. Computer-based risk evaluation methods are required as practical tools to automatically compare and evaluate contaminated sites. ALTRISK and HYDRISK are two examples of knowledge-based systems useful for environmental analysis. What types of problems must be solved by the geosciences that are relevant to environmental issues? Is it possible to define a special field of "environmental geology" that is distinct from the other branches of the geosciences? Geoscientists have always believed that it is part of their responsibility to find solutions to environmental problems. These questions have been treated for many years in numerous publications and discussions, and have been considered in educational programs. The environmental sciences are characterized by pragmatism. Research must be restricted to that which is sensible and leads to further decisions and actions that result in solutions which are acceptable with respect to their consequences. There are two essential aspects of environmental research: 1) Investigators should use scientific, empirically reproducible methods; and 2) Research should be driven by the significance and consequences of any potential risk—for example, the environmental impact on human health. These aspects cannot be considered separately. Pragmatic considerations determine the modality and resolution of the research. This has the effect of "styling" the mode of operation and the approach to specific problems. The method of sampling influences the perception of effects in a specific situation and also determines the assessment of risk. Because of the very complex correlations between many causes, risk cannot be determined in an exact manner. It is necessary that an expert be asked for an opinion of the degree of risk involved, based on his or her past experience in similar circumstances. Environmental research requires interdisciplinary investigations and the integration of knowledge from different fields. Even taking into account all of the known interrelationships, an exact evaluation of the risk may be impossible. The very complex problems dealt with by geoscientific environmental research are characterized by many interactions that depend upon conditions within the system.
Acceptable Evidence in a Pluralistic Society
Authors: Jasanoff Sheila
Published: November 2020

In recent years policy analysts have come to recognize cross-national comparison as a technique for illuminating noteworthy or desirable elements of decisions in particular national contexts (Heidenheimer, Heclo, and Adams 1975). This approach has proved especially fruitful in studies of science-based regulation. Comparisons between countries have helped identify institutional, political, and cultural factors that condition decision makers' use of scientific knowledge. This research has demonstrated, for example, that the analysis of evidence, especially in fields characterized by high uncertainty, can be influenced by the participation of differing classes of professionals in the administrative process, the composition and powers of scientific advisory committees, and the legal and political processes by which regulators are held accountable to the public (Brickman, Jasanoff, and Ilgen 1985; Gillespie, Eva, and Johnston 1979; McCrea and Markle 1984; Jasanoff 1986, 1987). As a result, it is by no means uncommon to find decision makers interpreting the same scientific information in different ways in different countries. Cultural variation appears to influence not only the way decision makers select among competing interpretations of data but also their methods of regulatory analysis and their techniques for coping with scientific uncertainty. For instance, in assessing both environmental and economic impacts, U.S. regulators place a higher value on formal analytical methods, whose validity can be publicly tested and verified, than do regulators in most European countries (Jasanoff 1983; Vogel 1986). One result of such methodological divergence is that evidence considered sufficient to trigger action in one country may fail to do so in another. These findings should not be surprising to anyone familiar with the problems of policy-relevant science. When knowledge is uncertain or ambiguous, as is often the case in science bearing on policy, facts alone are inadequate to compel a choice. Any selection inevitably blends scientific with policy considerations, and policymakers accordingly are forced to look beyond science to legitimate their preferred reading of the evidence. In this quest, cross-national divergences can be expected to appear as policymakers fall back on established, possibly nation-specific, repertoires of institutional and procedural approaches to securing political legitimacy.
Guidelines for Communicating Information About Chemical Risks Effectively and Responsibly
Authors: Covello Vincent T. , Sandman Peter M.
Published: November 2020

The Emergency Planning and Community Right-to-Know Act of 1986 (Title III of the Superfund amendments) and many state and local laws are imposing much more openness on the chemical industry. During the next few years, industry officials, government officials, and representatives from public-interest groups will increasingly be called upon to provide and explain information about chemical risks to the general public and to people living near chemical plants. This chapter presents and discusses guidelines for communicating informatio about chemical risks effectively, responsibly and ethically. A basic assumption of the chapter is that discussing risk, when done properly, is always better than withholding information. In the long run, more effective, responsible, and ethical risk communication will be better for communities, industry, government, and society as a whole. The chapter consists of four parts: (1) guidelines for communicating risk information, (2) guidelines for presenting and explaining risk-related numbers and statistics, (3) guidelines for presenting and explaining risk comparisons, and (4) problems frequently encountered in communicating risk information. Most of the material in this chapter deals with health risks, not the risks of accidents. In some cases, accidents raise similar communication issues, especially when most of the expected adverse health effects are long term rather than immediate. However, when considering the risks of accidents, it is generally best to focus on preventive measures, emergency response procedures, containment and remediation procedures, and the extent of the possible damage. There are no easy prescriptions for communicating risk information effectively, responsibly, and ethically (Table 4.1). But those who have studied and participated in debates about risk do generally agree on seven principles that underlie effective risk communication (Covello and Allen 1988). These principles apply equally well to both the public and the private sectors; (Covello and Allen 1988; Covello, McCallum, and Pavlova 1989; Covello, Sandman, Slovic 1987; Covello, von Winterfeldt, and Slovic 1989; Hance, Chess, and Sandman 1987; Krimsky and Plough 1988). Although many of these principles may seem obvious, they are continually and consistently violated. Thus a useful way to read them is try to understand why they are frequently not followed.
Phenomenological treatment of electron-transfer reactions
Authors: Schmickler Wolfgang
Published: November 2020

Electron-transfer reactions are the simplest class of electrochemical reactions. They play a special role in that every electrochemical reaction involves at least one electron-transfer step. This is even true if the current across the electrochemical interface is carried by ions since, depending on the direction of the current, the ions must either be generated or discharged by an exchange of electrons with the surroundings. In general electron-transfer reactions can be quite complicated, involving breaking or forming of chemical bonds, adsorption of at least one of the redox partners, or the presence of certain catalysts. So far our understanding is limited to the simplest possible case, so-called outersphere electron-transfer reactions, in which from a chemist's point of view nothing happens but the exchange of one electron - as we shall see later, the simultaneous transfer of two or more electrons is highly unlikely. In the course of such a reaction, no bonds are broken or formed, the reactants are not specifically adsorbed, and catalysts play no role. If one of these conditions is not fulfilled, the reaction is said to proceed via an inner-sphere pathway.