bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluvial Sediment, Forms, and Processes
Authors: Graf William L.
Published: November 2020

Although there are numerous aspects of sediment that might be considered in conjunction with questions related to plutonium transport and storage in rivers, particle size is the critical characteristic. Information on the size distribution of particles in sedimentary deposits connects plutonium, sediment, and river processes. An explanation of the geography of plutonium in the regional river system requires knowledge of particle sizes, the distribution of those particle sizes, and their potential mobility in the regional canyons, rivers, and reservoirs. Some general data concerning the size characteristics of fluvial sediment in the Rio Grande system are available from published sources for a few locations, particularly Los Alamos Canyon. Recent, previously unpublished field and laboratory investigations provide additional detailed information for the changing sedimentary environments associated with the river system. This chapter reviews the characteristics of river sediments in the Northern Rio Grande and presents a regional sediment budget from historical and geographical perspectives. Almost 200 sediment samples from deposits of various ages near the channels of the Rio Grande and tributaries demonstrate the variability of the sediment particle sizes. The analysis had three parts: sample collection, sieving, and electronic particle analysis. In the sample-collection phase, collection sites represented identifiable sedimentary units or channel deposits. Each collection site yielded three samples to indicate local variability. Penetration of the surfaces to depths of 5 to 90 cm with a standard cylindrical soil probe provided masses of about 120 g each for laboratory analysis. Investigators kept only the split of the sample that included those particles with diameters of less than 2 mm (that is, sand size or smaller). Laboratory procedures included sieving and electronic counting. Sieving divided each sample into masses consisting of those particles larger than 63 microns in diameter (the sand fraction) and those smaller than 63 microns (the silt and clay fraction). The weight of each fraction provided a standarized means of comparing the samples for this study and the results reported by other researchers. Analysis of the silt and clay fraction using a Coulter electronic particle analysis system permitted a detailed investigation of the frequency distribution of the particles in this restricted range.
Information Processing: Rational and Irrational Transcended
Authors: Anderson E. N.
Published: November 2020

A large and probably increasing proportion of literature on the environment is based on the assumptions of rational choice theory. People are held to be almost errorless maximizers of individual utility. They are seen as being quite clear about their goals, having perfect information about the means to achieve those goals, and being able to calculate rapidly and precisely the exact trade-offs and Bayesian optima that allow them to reach their goals by the most cost-effective method. A further assumption, often unspoken (occasionally even denied) but in practice almost always accepted, is that people’s goals are narrowly individualistic—short-term and narrow, not long-term and wide. This assumption is not really entailed by rational choice theory, but rational choice theorists often make it. Rational choice theory has its uses, but these assumptions are questionable (at the very least). Perhaps the commonest counterview in the environmental literature is based on the assumption that rational individualism is a product of the modern capitalist world, and that other peoples have based their lives on more communitarian and ecologically sensitive intuitions. Carolyn Merchant, chronicler of Radical Ecology, provides a particularly powerfully argued summary of the variants of this view. Unfortunately, anthropological evidence shows fairly conclusively that many premodern cultures ruined their environments through shortsighted and wasteful practices (see chapter 8). This chapter argues for a different way of understanding human successes and mistakes. A number of lines of evidence suggest that humans do indeed practice something like the rational calculus but that they are not perfect at it and that they are greatly influenced by social and emotional factors. The result is that their decision making often closely approximates rational choice but often deviates from rational choice models in dramatic but often predictable ways. This fact goes a long way to explain many of the mistakes we see in environmental management. It also helps explain the question posed earlier in this book : Why do people often use religious and mythic institutions to motivate rational behavior? If rational choice theory were adequate, people would not need the panoply of religion and myth to get them to act sensibly.
Fundamental Equations
Authors: Phan-Thien Nhan , Kim Sangtae
Published: November 2020

There is a need for theoretical and computational tools that provide macroscopic relations for a composite continuum, starting from a description of the composite microstructure. The outlook for this viewpoint is particularly bright, given current trends in high-performance parallel supercomputing. This book is a step along those directions, with a special emphasis on a collection of mathematical methods that together build a base for advanced computational models. Consider the important example of the effective bulk properties of fiberreinforced materials consisting of fibers of minute cross section imbedded in a soft elastic epoxy. The physical properties of such materials is determined by the microstructure parameters: volume fraction occupied by the fibers versus continuous matrix; fiber orientations; shape of the fiber cross sections; and the spatial distribution of fibers. Hashin notes that “While for conventional engineering materials, such as metals and plastics, physical properties are almost exclusively determined by experiment, such an approach is impractical for FRM (fiber-reinforced materials) because of their great structural and physical variety,” The analysis of warpage and shrinkage of reinforced thermoset plastic parts provides yet another example of the important role played by computational models. The inevitable deformation of the fabricated part is influenced by the interplay between constituent material properties, the composite microstructure and macroscopic shape of the component. Computational models play an important role in controlling these deformations to minimize undesired directions that lead to warpage and shrinkage. The strength, stiffness, and low weight of these materials all result from the combination of a dispersed inclusion of very high modulus imbedded in a relatively soft and workable elastic matrix. It thus appears reasonable, as a first approximation, to consider a theory for the distribution of rigid (infinite modulus) inclusions in an elastic matrix, reserving the bulk of our efforts for the study of the role of inclusion microstructure. A framework for computational modeling has been established for materials processing, using models of microstructure with simplified rules for the motion of the inclusions.
The Philosophy of Science
Authors: Blum Bruce I.
Published: November 2020

This chapter presents an overview of the philosophy of science. why study this philosophy? Here is my justification. we know that the software process is a transformation from the identification of a need in-the- world into a set of computer programs that operate in-the-computer. The process begins with an idea, a concept, something that may defy a complete description, and it ends with the delivery of a formal model that executes in the computer. As we have seen, there is a fundamental tension in this transformation, a tension between what we want and how we make it work, between the requirements in-the-world and their realization in-the-computer, between the subjective and the objective, the conceptual and the formal. This book seeks to resolve that tension. Science faces a similar problem, and so I start by examining its solutions. Science begins with something very complex and poorly represented—the real world—and its goal is to describe aspects of that reality with theories and models. we know that science is successful. It is reasonable to look, therefore, into its strengths and limitations for insight into resolving the software process’ central tension. To gain this insight, I turn to the philosophy of science because it constitutes a kind of meta-science. It examines the nature of science from a theoretical perspective; it helps us appreciate what is knowable and what can be represented formally. I note at the outset, this is not my area of expertise. Moreover, the philosophers of science have not reached a consensus. Philosophical inquiry is, by its very nature, controversial and argumentative, and the theme of this chapter is the underlying controversies regarding the nature of science and scientific knowledge. If we are to find “scientific foundations,” then we must first understand what science is (and is not)—the topic of what follows. I warn the reader that this chapter conforms to truth in labeling; as its title indicates, it literally is about the philosophy of science. There are a few explanatory comments that tie the material to the immediate needs of a software engineer, but this really is a chapter about philosophy.
System Implementation
Authors: Smith Ronnie W. , Hipp D. Richard
Published: November 2020

Without development of an actual working system it is impossible to empirically validate the proposed computational model. Thus, the architecture introduced in section 3.1 has been implemented on a Sun 4 workstation and later ported to a Spare II workstation. The majority of the code is written in Quintus Prolog while the parser is written in C. The system software is available via anonymous FTP as described in appendix C. The overall hardware configuration is illustrated in figure 6.1. Speech recognition is performed by a Verbex 6000 user-dependent connected-speech recognizer running on an IBM PC. The vocabulary is currently restricted to the 125 words given in table 7.1. Users are required to begin each utterance with the word “verbie” and end with the word “over” (e.g. “verbie, the switch is up, over”). The Verbex speech recognizer acknowledges each input with a small beep. These sentinel interactions act as a synchronization mechanism for the user arid the machine. Speech output is performed by a DECtalk DTCO1 text-to-speech converter. This chapter discusses the following technical aspects of the implementation. • The various knowledge representation formalisms. • The implemented domain processor, an expert system for assisting in simple circuit repair. • The implemented generation component. • The basic physical resource utilization of the system. The basis for the implementation has been the logic programming language, Prolog. Clocksin and Mellish [CM87] provide an introduction to this language. Pereira and Shieber [PS87] arid McCord [McC87] can be consulted for a discussion of the usage of Prolog for natural language analysis. Prolog allows the expression of rules and facts in a subset of first-order logic called Horn clauses. Prolog is supplemented with non-logical features that aid in efficient computation as well, but as a representational formalism, its utility in representing rules and facts in a declarative format provides a basis for the representation of knowledge and rules within the model. The Goal and Action Description Language was introduced in section 3.2.2. A detailed description is provided in appendix A. It is used as a standard formalism for representing goals that may be accomplished during a task.
Arranging a Marriage: Ecology and Agriculture
Authors: Worster Donald
Published: November 2020

We hear these days a repeated call by scientists, agricultural reformers, and environmentalists to effect a marriage between agriculture and the science of ecology—to create a new agroecology and a new ecologically based agriculture. Each party needs the other, it is said, but agriculture in particular needs this marriage and this spouse, if it is have a more secure, less environmentally destructive future. So far we have heard mainly the views of ecologists, who might be described as the bride pursuing the groom, who is agriculture. We don’t, however, really know what agriculture thinks about the idea, whether he thinks about it at all, or whether he is really the marrying kind. Those of us who are mere observers to the marriage proposal, including this historian, may support the idea of matrimony on general principles but confess to being a little nervous and uncertain as to whether such a union would work or not. Who is this potential groom, agriculture, and what has been his past? A very complicated fellow, he is the farmer in the field, of course, but also the rural banker, farm implement manufacturer, pesticide salesman, international grain merchant, and food processor. He is modern agribusiness in all its manifestations. He works hard, is full of self-confidence, and wants no interference with his work. Yet these days he is a ward of the government, unable to function alone. He is full of contradictions, not only between his insistence on free enterprise and his simultaneous demand for public support, but also between his ancient memories of stability and harmony and his modern drive for wealth and power. The first and most difficult task for the bride is to convince this fellow that he needs a mate. Before he will come to the altar, he must be brought to understand that his life is incomplete as it is, that in fact it is a mess. He must see that he needs to reform himself if he has any hopes of surviving and that the proposed marriage with ecology can be the first step toward that reform.
Moralists and Aggregators: The Case of Muir and Pinchot
Authors: Norton Bryan G.
Published: November 2020

Gifford Pinchot first met John Muir in 1896, while on a trip through the West to study possible sites for new forest preserves. Pinchot was much impressed by Muir, twenty-seven years his senior, and recalled the meeting fifty years later in his autobiography. He described Muir as “cordial, and a most fascinating talker, I took to him at once.” Muir, in his writings of this period, was explicitly complimentary of Pinchot’s efforts at sustainable forestry. At the Grand Canyon, Muir and Pinchot struck off on their own and “spent an unforgettable day on the rim of the prodigious chasm, letting it soak in.” They came across a tarantula and Muir wouldn’t let Pinchot kill it: “He said it had as much right there as we did.” Within a year, however, Muir had complained bitterly and publicly about Pinchot’s decision to allow grazing in the national forest reserves. This rift between the Moralist (Muir) and the Aggregator (Pinchot) shaped the two wings of the environmental movement, and its original configuration owes much to attitudes developed in the early life and work of each man. Muir entered the University of Wisconsin in 1861, the year the Civil War broke out. Although he was almost twenty-three, his last formal schooling had been interrupted at the age of eleven, when his family emigrated from Scotland. His father, Daniel, a religious zealot, had no use for any book but the Bible. The elder Muir, who joined ever more extreme sects in search of one sufficiently pure and exacting, chose eighty acres of virgin land and put his eldest son John to work clearing it. Days were spent cutting trees and grubbing out roots, and nights were given over to memorizing Scripture. Daniel Muir planted only corn and wheat for cash crops, and the farmland was worn out in only eight years. Choosing a new and larger plot, the family moved and repeated the process. Again, the hardest work fell to John as his father spent all of his time studying the Bible and preaching to anyone who would listen.
Introduction
Authors: Hoyt Douglas V. , Shatten Kenneth H.
Published: November 2020

About 400 years before the birth of Christ, near Mt. Lyscabettus in ancient Greece, the pale orb of the sun rose through the mists. According to habit, Meton recorded the sun’s location on the horizon. In this era when much remained to be discovered, Meton hoped to find predictable changes in the locations of sunrise and moonrise. Although rainy weather had limited his recent observations, this foggy morning he discerned specks on the face of the sun, the culmination of many such blemishes in recent years. On a hunch, Meton began examining his more than 20 years of solar records. These seemed to confirm his belief: when the sun has spots, the weather tends to be wetter and rainier. Theophrastus reported these findings in the fourth century B.C. Other ancient accounts concerning the sun and weather are vague. If one stretches one’s imagination, some comments by Aratus of Soli, Virgil, and Pliny the Elder may touch on this subject. What happened to the original records used by Theophrastus? Perhaps these and related scientific data were burned in the fire that destroyed the Library at Alexandria around A.D. 300. Other possible ancient accounts have vanished. Two thousand years passed. The Roman Empire rose and fell, the Dark Ages lasted a thousand years, and Europe entered the Renaissance. The 1600s reveal perhaps half a dozen scattered references to changes in the sun and their effect on weather. After a few more references in the 1700s, scientific interest in the sun waned. Following Sir William Herschel’s comments on sunspots and climate in 1796 and 1801, about 10 scientific papers touched on the sun’s influence on climate and weather. The next two decades contain about 10 or so references to this topic. Shortly after a paper by C. Piazzi Smyth appeared in the proceedings of the Royal Society in 1870, the field exploded. This paper stimulated scientists such as Sir Norman Lockyer, Ferguson, Meldrum, and others to think about solar and terrestrial changes. Meldrum, a British meteorolo gist in India, considered Indian cyclones. His tabular values are compared with sunspot numbers in Figure 1.1.
Climate Measurement and Modeling
Authors: Hoyt Douglas V. , Shatten Kenneth H.
Published: November 2020

Having considered the sun and its variations, we now turn to Earth’s climate and climatic variations. We examine the definition of climate and the difficulties in measuring it. Awareness of these complexities is critical for an appreciation of how difficult it is to demonstrate changing climate. Separating trends from random variations is the first step in defining climate change. After reviewing the statistical properties of climate, we deal with theoretical climate models. This background is important for understanding how solar variations might affect climate. The following four chapters review specific sun/climate relationships, and the statistical and physical guidelines developed now will be used to select pertinent studies. As the heat source that drives Earth’s climate, the variable sun is important when studying climate change. With many, if not most, modern popular accounts focusing on how humanity is altering climate, it is important to realize that solar variations may play a significant role in the background natural variability. To understand anthropogenic (human-made) influences on climate change, we must be able to make distinctions among the contributions that arise from naturally occurring climate variability. Natural climate variations include a possible solar-irradiance component. Man-made climatic changes are not well known, and natural climate variations are uncertain too. For example, we do not know whether a man-made doubling of atmospheric carbon dioxide provides a 1.5 or a 4.5 °C increase in mean global temperature. This uncertainty arises, in part, because natural climate variability acts as “noise” to confuse our measures of man-made influences. To obtain accurate results, we must understand and remove these background noise sources. Although these temperature changes seem small, they can have tremendous global impact on the survivability of species and on many different aspects of life. In addition, the uncertainty factor of 3 is highly important because it tells us that the risk in emitting a quantity of carbon dioxide is uncertain by this same factor.
Gaia or Athena? The Early Faint-Sun Paradox
Authors: Hoyt Douglas V. , Shatten Kenneth H.
Published: November 2020

Stellar evolution theory predicts large, long-term solar large, long-term solar luminosity (L⊙) changes over the lifetime of the sun. The most certain prediction is a general monotonic increase (neglecting short-period variations) in L⊙ of about 30% over the past 4.7 billion years, an increase that will continue. This prediction is well founded theoretically (based on the conversion of hydrogen into heavier elements) and supported observationally by the famous Hertzsprung-Russell diagram showing stellar evolution. If the solar luminosity increases monotonically with time, one might expect to find evidence of increasing surface temperatures in the Earth’s paleoclimatic record. Instead, isotopic indicators show Earth’s mean surface temperature is now significantly lower than it was 3 billion years ago. In 1975, R. K. Ulrich termed this the “faint young sun” paradox. Simultaneous solar luminosity increase and terrestrial temperature decrease imply additional strong influences on climate evolution. To understand climate evolution (and, by inference, the present climate), we must first determine the nature of these “compensatory mechanisms.” The positively increasing line in Figure 12.1 shows the evolution of solar luminosity (in units of present luminosity, L). Since terrestrial surface temperatures have remained nearly constant during the last 2.3 billion years, this requires a very effective compensatory mechanism. Several theories attempt to explain why the Earth’s surface temperature has remained relatively constant even while the solar luminosity has increased by 30%. Also, various scenarios have been advanced to explain why the Earth remained ice-free even during periods when the sun was much dimmer than it is today. Some of these ideas are: • Since it had fewer continents and more oceans, the early Earth was much darker. This same darker surface absorbed enough additional incoming solar radiation to remain ice-free. • In the past, energy transport from the equator to polar regions was easier because the continents had lower elevations. This enhanced heat transport allowed the Earth to remain relatively warm. • The early atmosphere had more carbon dioxide and methane, creating an enhanced greenhouse effect sufficient to trap the incoming solar radiation and keep the Earth warm. The enormous amount of carbon trapped in limestone suggests that Earth’s former atmosphere contained much more carbon dioxide than it does today.
Electrolyte Solutions
Authors: Fawcett W. Ronald
Published: November 2020

Electrolyte solutions are important in all branches of chemistry, but especially in analytical chemistry, and biochemistry. These systems by their nature are always non-ideal, and represented an early challenge to theoreticians interested in describing their thermodynamic properties. The solute components are ions, cations, and anions, which carry opposite charges and thus interact very differently with one another. The existence of electrolyte solutions depends on the polar properties of the solvent through which the individual ions are stabilized. When one recognizes the molecular nature of the solvent, one must also consider the interactions between solvent dipoles and the ion. This results in changes in solvent structure in the immediate vicinity of the ions. It follows that a complete description of an electrolyte solution at the molecular level requires the consideration of ion–dipole, ion–ion, and dipole–dipole interactions. In addition to these simple electrostatic interactions, one must also consider the role of hydrogen bonding in protic solvents like water. In very dilute electrolyte solutions, the most important consideration is ion– dipole interactions. One expects these interactions to be different for cations and anions. This follows from the fact that the solvent molecule is not a simple dipole in the electrostatic sense but instead it has a chemical structure which is different at each end of the molecular dipole. Each ion interacts locally with four to six solvent molecules in its immediate surroundings. In the case of water, the concentration of water molecules in the pure liquid is 55.5 M; it follows that the number of water molecules experiencing direct interaction with ions in dilute solutions represents a small fraction of the total number. As the electrolyte concentration increases, ion–ion interactions become more important in determining the thermodynamic properties of the solution. The electrostatic field of an ion is long ranged, decreasing with the reciprocal of the distance from the charge center of the ion. As a result a given ion has an ionic atmosphere in which the concentration of oppositely charged ions in its vicinity is slightly greater on the average than that of ions of the same charge.
Introduction
Authors: Krishnamurti T. N. , Bedi H. S. , Hardiker V. M.
Published: November 2020

The spectral modeling approach to numerical weather prediction is being practiced in many parts of the world. Historically, the spectral approach came into atmospheric sciences from studies of geomagnetism, where it was introduced by Elsasser in the late nineteenth century. The first attempt of spectral representation of data sets and its use via simple vorticity conserving models came in the 1940s. The works of Neamtan (1946) from the University of Manitoba and Haurwitz (1940) and Craig (1945) from New York University were pioneering during this era. These were still close to linear problems, lacking any formalism for addressing the nonlinear advective dynamics. It was in the late 1950s when we saw the emergence of formal proposals for the solution of the nonlinear barotropic vorticity equation. Pioneering work from the University of Chicago (Platzman 1960; Baer 1964) explored what is sometimes called the interaction coefficients approach for the nonlinear problem. Around the same time at MIT we saw the elucidation of what are now called the low-order systems. This pioneering work of Lorenz (1960b) and Saltzman (1959) brought to us the first exposure to simple nonlinear systems and the concept of chaos. These simple three-component systems demonstrated some of the essentials of nonlinear dynamics and the growth of errors arising from initial state uncertainties. The interaction coefficients approach to the solution of the weather forecast problem led to unmanageably large memory requirements that were not easily amenable to the then available, or even to the present, memory of computers. It was during the mid-1950s when the Cooley-Tukey algorithm (1965) emerged and provided a breakthrough via the fast Fourier transform. This was exploited and demonstrated to provide accurate representations of the quadratic terms for fast computation of the nonlinear advective dynamics by contributions from Eliasen et al. (1970) and Machenhauer (1974) from the University of Copenhagen and from Orszag (1970) at MIT. Thereafter, we saw a rapid development of global spectral models in many parts of the world, especially Australia, Canada, England, Japan, and the United States.
What Is a Spectral Model?
Authors: Krishnamurti T. N. , Bedi H. S. , Hardiker V. M.
Published: November 2020

If one takes a closed system of the basic meteorological equations and introduces within this system a finite expansion of the dependent variables using functions such as double Fourier or Fourier-Legendre functions in space, then the use of the orthogonality properties of these spatial functions enables one to obtain a set of coupled nonlinear ordinary differential equations for the coefficients of these functions. These coefficients are functions of time and the vertical coordinate, since the horizontal spatial dependence has been removed by taking a Fourier or a Fourier-Legendre transform of the equations. The coupled nonlinear ordinary differential equations for the coefficients are usually solved by simple time-differencing and vertical finite-differencing schemes. The mapping of the solution requires the multiplication of the coefficients with the spatial functions summed over a set of chosen finite spatial basis functions. This is what defines spectral modeling. Meteorological application of the spectral method was initiated by Silberman (1954), who studied the nondivergent barotropic vorticity equation in the spherical coordinate system using the spectral technique. In its earlier days, the spectral method was particularly suitable for low-resolution simple models. The equations of these simple models involved nonlinear terms evaluated at each time step. Evaluation of the nonlinear terms was performed using the interaction coefficient method and thus required large memory allocations, which was an undesirable proposition. However, with the introduction of the transform method, developed independently by Eliasen et al. (1970) and Orszag (1970), the method for evaluation of these nonlinear terms changed completely. This transform method also made it feasible to include nonadiabatic effects in the model equations. For the past couple of decades, the spectral method has be come an increasingly popular technique for studies of general circulation and numerical weather prediction at the operational and research centers. This method forms the basis for spectral modeling, and it is easy to understand if the reader has some background in linear algebra. We have a set of linearly independent functions θi(x), which are called the basis functions. The dependent variables of the problem are represented by a finite sum of these basis functions.
Introduction
Authors: Brown Alan W. , Carney David J. , Morris Edwin J. , Smith Dennis B. , Zarrella Paul F.
Published: November 2020

Computers have a significant impact on almost every aspect of our lives. Computer systems are used as integral components in the design of many of the artifacts we use and the homes we inhabit. They also control the operation of a number of devices we frequently use, and record information on many of the significant actions we take in our daily lives. The rapid increases in performance and reliability of computer hardware, coupled with dramatic decreases in their size and cost, have resulted in an explosion of uses of computer technology in a wide variety of application domains. A consequence of this trend is that computer software is in great demand. In addition to new software being written, many millions of lines of existing software are in daily use, and require constant maintenance and upgrade. As a result, computer software is very often the overriding factor in a system’s costs, reliability, performance, and usability. Software that is poorly designed, implemented, and maintained is a major problem for many companies that make use of computer systems. These facts have led to increasing attention being placed on the processes by which software is developed and maintained, and on the computer-based technology that supports these activities. Over the past decade or more, this attention has focused on understanding better how software can be produced and evolved, and on providing automated support for these processes where appropriate. One of the consequences of this attention has been the development of the field of computer-aided software engineering (CASE), which directly addresses the needs of software engineers themselves in the use of computerbased technology to support their own development and maintenance activities. The promise of CASE is that automated support for some aspects of software development and maintenance will: • increase productivity and reduce the cost of software development, • improve the quality (e.g., reliability, usability, performance) of software products, • keep documentation in step with software products as they evolve, • facilitate maintenance of existing software systems, and • make the software engineers’ task less odious and more enjoyable.
Effects of Stress
Authors: Oertel Gerhard
Published: November 2020

The simplest relationship between stress and strain is Hooke’s law, describing the linear elastic response of solids to stress. Elastic strain (almost in all cases small) is proportional to the applied stress, with one proportionality factor expressing the relationship between normal, and another that between tangential stress and strain. An ideally elastic strain is completely reversed upon removal of the stress that has caused it. Most materials obey Hooke’s law somewhat imperfectly, and that only up to a critical yield stress beyond which they begin to flow and to acquire, in addition to the elastic strain, a permanent strain that does not revert upon stress release. Hooke’s law in this form is applied to materials that are elastically isotropic, or can be assumed to be approximately so. Crystals, however, never are elastically isotropic, nor are crystalline materials consisting of constituent grains with a distribution of crystallographic orientations that departs from being uniform. The response of a crystal to a stress (at a level below the yield stress) consists of a strain determined by a matter tensor of the fourth rank, the compliance tensor s i j k l : . . . ɛij = s i j k l σkl, (7.1) . . . the 81 components of which are constants. Any tensor that describes the linear relationship between two tensors of the second rank is necessarily of the fourth rank, and like other tensors of the fourth rank, the compliance tensor can be referred to a new set of reference coordinates by means of a rotation matrix aij: s i j k l = aimajnakoalp smnop. (7.2) . . . The components of the compliance tensor are highly redundant, first because both the stress and the strain tensors are symmetric, and second because the tensor itself is symmetric. The number of independent components for crystals of the lowest, triclinic (both classes) symmetry is 21, and with increasing crystal symmetry the redundancies become more numerous; only three independent compliances are needed to describe the elastic properties of a cubic crystal.
User Rights and Biodiversity Conservation
Authors: Miranda Marie Lynn , LaPalme Sharon
Published: November 2020

The management of tropical forests has evolved considerably during recent decades. In the 1970s, the colonial and postindependence emphasis on maintaining large plantations and maximizing timber production gave way to a dual emphasis on revenue generation and social forestry. More recently, the international community, including developing countries themselves, has begun to recognize the important environmental services provided by tropical forest resources, including water quality, soil retention, biodiversity, and microclimate and macroclimate regulation. Just as the prevailing view of appropriate objectives for tropical forest management has changed, so has support for the devolution, or transfer, of rights to local people. Under the previous forest-management paradigm, which stressed revenue generation and social forestry, governments and international aid agencies encouraged nationalization of forests and the gazetting of land into systems of state forest preserves. This served, perhaps unintentionally but nevertheless forcefully, to restrict the rights of locals. But as the relationship between the landless poor, indigenous groups, and the forest resource came to be better understood, more consideration was given to allowing communities to retain or gain customary and/or legal rights to the forest resource. Now, however, by adding the protection of environmental services to the management paradigm, the effects on the devolution of rights to local people are much less clear. On the one hand, some would argue that the only way to vest locals in the maintenance of the forest resource is to give them specific, income-enhancing rights to its use. On the other hand, examples abound of local populations who have exploited the forest resource in ways that are not sustainable, destroying fragile ecological relationships and degrading the biodiversity of the area in the process. The support for devolution of rights has waxed and waned over the years, with its popularity dependent on both international politics and the world economy. The question of whether to devolve rights becomes especially complicated when considering the fate of protected areas in the tropical developing world. Within the protected areas themselves, user rights exercised by local people either can be relatively benign or can have devastating effects on the local ecosystem.
Compensation and Economic Incentives: Reducing Pressure on Protected Areas
Authors: Ferraro Paul J. , Kramer Randall A.
Published: November 2020

Although the global social benefits of establishing protected areas in tropical rain forests may outweigh the total costs, the local private costs of restricting access to an important resource may be relatively substantial for residents and communities. The imbalance between costs accruing at the local level and benefits accruing at the national and international levels has raised questions about whether people living in or near protected areas ought to be compensated for their losses, and if so, how compensation should be made. The issue of compensating residents for lost resources has been discussed, implicitly or explicitly, in many treatments of the relationship between protected areas and local people, as well as in treatments of externalities. (Economists define externalities as actions of consumers or producers that affect the well-being of others in a way that is not reflected through prices or economic transactions.) In the literature on compensation, there is a large difference of opinion on whether compensation should be paid to victims of negative externalities, which include such things as the pollution of air or water and the siting of hazardous waste dumps. A number of studies have argued for compensation of those people subject to negative externalities, at least in particular situations or through particular mechanisms Oohnson, 1977; O'Hare, 1977; Western, 1982; Knetsch, 1983; Ward, 1986; Tietenberg, 1988; Hodge, 1989; Sullivan, 1990, 1992; Barnett, 1991; Burrows, 1991; McNeely, 1991; Miceli, 1991; Farber, 1992; Pollot, 1993). Other authors, mainly economists, have argued equally persuasively against compensation in many or all situations (Knetsch, 1983; Blume et al., 1984; Baumol and Gates, 1988). Most of the differences of opinion derive from differences in the context of the case examined, the assumptions made, the criteria used for judging the desirability of outcomes, interpretations of relevant laws, and the proposed mechanism for compensation. In the context of protected areas, most authors have argued in favor of compensating residents (e.g., Western, 1982; Barnett, 1991; McNeely, 1991). A unique best choice regarding compensation is not indicated in economic and political theory. Few protected area projects have attempted large-scale compensation initiatives; thus, there are few field examples to guide the discussion.
Conservation Biology
Authors: Wheelwright Nathaniel T.
Published: November 2020

Each February, when I return to Monteverde to study the reproductive ecology of lauraceous trees, I stay with friends in their farmhouse tucked on the edge of the lower montane moist forest. On my first morning back, I am always eager to listen to the dawn bird chorus. During my most recent visit, I awoke to hear a cacophony of Great-tailed Crackles, a noisy flock of Brown Jays, an exuberant House Wren, and a gang of Bronzed Cowbirds squabbling over spilled grain by the cow barn. Back in 1978, during my first visit, there were no Great-tailed Crackles in Monteverde. Brown Jays had colonized the area, but their flocks were relatively small and restricted to the lower parts of the community. House Wrens, always familiar denizens of Monteverde’s yards and farms, are more abundant today than ever. Once a rarity in Monteverde, Bronzed Cowbirds are now common. Monteverde has changed, and more changes are coming. The rest of Monteverde’s avifauna has undoubtedly felt an impact from the explosive population growth of these bird species. Crackles and jays prey on the eggs, nestlings, and fledglings of other birds; wrens also occasionally destroy other birds’ eggs. Cowbirds are brood parasites. All four species potentially compete with other species for food. Without censuses from earlier years, it is impossible to know how newly colonizing species have affected the fauna and flora of Monteverde. Contributors to this book have provided evidence that various species of animals and plants, especially widespread species of Costa Rica’s lowlands and foothills, have expanded their ranges and increased their population sizes in Monteverde. At the same time, other species are rarer than they used to be only a few decades ago. I used to marvel at the frenzied breeding aggregations of Golden Toads, hold multicolored Harlequin Frogs, and listen to nightly serenades of glass frogs along the Río Guacimal. Most of them no longer exist in Monteverde. In this chapter my goals are to (1) highlight aspects of the biodiversity of Monteverde that are relevant to conservation, (2) give a brief overview of general concepts in conservation biology, (3) discuss conservation problems that are specific to Monteverde and neotropical highland forests, and (4) consider how principles of conservation biology might provide solutions to those problems.
Computational Tools
Authors: Epstein Irving R. , Pojman John A.
Published: November 2020

It is fair to say that the field of nonlinear chemical dynamics would not be where it is today, and perhaps it would not exist at all, without fast digital computers. As we saw in Chapter 1, the numerical simulation of the essential behavior of the BZ reaction (Edelson et al., 1975) did much both to support the FKN mechanism and to make credible the idea that chemical oscillators could be understood without invoking any new principles of chemical kinetics. In 1975, solving those differential equations challenged the most advanced machines of the day, yet the computers used then were less powerful than many of today’s home computers! Despite the present widespread availability of computing power, there remain many challenging computational problems in nonlinear dynamics, and even seemingly simple equations can be difficult to solve or maybe even lead to spurious results. In this chapter, we will look at some of the most widely used computational techniques, try to provide a rudimentary understanding of how the methods work (and how they can fail!), and list some of the tools that are available. There are several reasons for utilizing the techniques described in this chapter: 1. For a complicated system, it is generally not possible to measure all of the rate constants in a proposed mechanism. One way to estimate the remaining parameters is to simulate numerically the behavior of the system, varying the unknown rate constants until the model satisfactorily reproduces the experimental behavior. 2. If a mechanism, which may consist of dozens of elementary chemical reactions, is valid, then it should reproduce the observed dynamical behavior. Proposed mechanisms are most commonly tested by integrating the corresponding rate equations numerically and comparing the results with the experimental time series, or by comparing the results of many such simulations with different initial conditions (or of a numerical continuation study) to the experimental phase diagram. 3. Numerical results can act as a guide to further experiments. The real reason for developing models is not to interpolate between our experimental observations but to extrapolate into unknown realms.
Coupled Oscillators
Authors: Epstein Irving R. , Pojman John A.
Published: November 2020

We have thus far learned a great deal about chemical oscillators, but, except in Chapter 9, where we looked at the effects of external fields, our oscillatory systems have been treated as isolated. In fact, mathematicians, physicists, and biologists are much more likely than are chemists to have encountered and thought about oscillators that interact with one another and with their environment. Forced and coupled oscillators, both linear and nonlinear, are classic problems in mathematics and physics. The key notions of resonance and damping that arise from studies of these systems have found their way into several areas of chemistry as well. Although biologists rarely consider oscillators in a formal sense, the vast variety of interdependent oscillatory processes in living systems makes the representation of an organism by a system of coupled oscillators a less absurd caricature than one might at first think. In this chapter, we will examine some of the rich variety of behaviors that coupled chemical oscillators can display. We will consider two approaches to coupling oscillatory chemical reactions, and then we will look at the phenomenology of coupled systems. We begin with some general considerations about forced oscillators, which constitute a limiting case of asymmetric coupling, in which the linkage between two oscillators is infinitely stronger in one direction than in the other. As an aid to intuition, picture a child on a swing or a pendulum moving periodically. The forcing consists of an impulse that is applied, either once or periodically, generally with a frequency different from that of the unforced oscillator. In a chemical oscillator, the forcing might occur through pulsed addition of a reactive species or variation of the flow rate in a CSTR. Mathematically, we can write the equations describing such a system as . . . dX/dt = f(x) + ε g(X, t) (12.1) . . . where the vector x contains the concentrations, the vector function f(x) contains all the rate and flow terms in the absence of forcing, g(x) represents the appropriately scaled temporal dependence of the forcing, and the scalar parameter e specifies the strength of the forcing.