bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrating Socioeconomic and Geographic Information Systems: A Methodology for Rural Development and Agricultural Policy Design
Authors: Stonich Susan
Published: November 2020

Understanding the factors related to destructive ecological processes in the tropics has expanded significantly in the last decade. Much has been learned about heterogeneity in geomorphology, soils, hydrology, and climate and about associated vulnerability to ecological damage. Research on cropping systems has divulged both the suitability and the liability in swidden agricultural practices and has led to recommendations involving alternative cropping and agroforestry complexes (Altieri 1987). At the same time, there has been a growing awareness that a more comprehensive knowledge of tropical ecology and enlarged technological and/or agricultural options will not necessarily affect a sustainable ecology (Altieri and Hecht 1990; Redclift 1984, 1987). Research on peasant economies in Latin America and elsewhere has demonstrated the existence of a highly differentiated peasantry, the vast majority of whom are landless or land-poor and who are more dependent on income earned from off-farm than from on-farm sources (Collins 1986; Deere and Wasserstrom 1981; Stonich 1991b). Such studies have demonstrated that systemic interconnections among family and corporate farmers with landholdings of all sizes promote environmental destruction (Stonich 1989); have established the existence of labor scarcity rather than labor surpluses in many peasant communities and the related environmental consequences (Brush 1977,1987; Collins 1987,1988; Posner and MacPherson 1982; Stonich 1993); and have called for rural and agricultural development policy that takes into account a socially differentiated peasantry and diversified rural poverty (de Janvry and Sadoulet 1989). It is increasingly evident that ecological destruction cannot be fathomed apart from the demographic, institutional, and social factors that influence the agricultural practices and other natural resource management decisions of agricultural producers. This paper describes a multidisciplinary methodology designed to examine the interactions among demographic trends, social processes, agricultural production decisions, and ecological decline in southern Honduras, a region characterized by widespread and worsening human impoverishment and environmental degradation. The methodology integrated the research efforts and databases compiled by anthropologists from the University of Kentucky using a farming systems approach, who were part of the socioeconomic component of the International Sorghum Millet Project (INTSORMIL) with potentially complementary research conducted by the natural and agricultural scientists working as part of the Comprehensive Resource Inventory and Evaluation System Project (CRIES) at Michigan State University.
Moving from Catchments to Cognition: Tentative Steps Toward a Larger Archaeological Context for GIS
Authors: Gaffney Vincent , Watson Helen
Published: November 2020

Geographical informations systems are being used increasingly frequently within archaeological applications. Given the nature of much archaeological data, there can be little doubt that this technology probably represents one of the most flexible and comprehensible tools for the analysis of spatial data presently available. However, there are causes for concern relating to the archaeological context of GIS. This paper suggests that the nature of most GIS is such that they are most readily applied to data that are most conveniently stored in map format and that this may ultimately be restrictive to the natural development of archaeological analysis. In particular it is suggested that the use of GIS modules may lead to the unwitting exposition of an environmentally or functionally deterministic viewpoint of a type that has largely been rejected by most archaeologists. The need to develop cognitive models is emphasized and it is suggested that GIS has an important role to play in the development of such approaches. Particular emphasis is placed on the ability of GIS to incorporate the whole environment within archaeological models and to transform abstract spatial information in order to place it within a cultural domain. Two case studies are presented to support these suggestions. The first involves the re-analysis of a GIS study of late prehistoric settlement and burial data on the island of Hvar by the authors. It is suggested that the original interpretation of these data can be greatly improved through a more thoughtful consideration of the belief systems operating within these communities. The second case study involves prehistoric rock art and other ritual monuments in mid-Argyll in southern Scotland. The GIS-generated viewshed data are used to explore the cognitive context of the monuments within the landscape and to explore the perceived relationship between monuments. The GIS clearly has a lot to offer archaeology. However, there is a need to ensure that we use the technology on the terms of archaeology rather than simply transfer the techniques for which GIS is most commonly used into an archaeological context.
The Politics of Settlement Choice on the Northwest Coast: Cognition, GIS, and Coastal Landscapes
Authors: Maschner Herbert D. G.
Published: November 2020

The reasons why evolutionary ecology and, more specifically, optimal foraging theory, do not work in many archaeological situations are varied. Most importantly however, is our lack of understanding of basic human decision-making processes in societies intermediate between bands and states. From evolutionary ecology, we can predict some foraging behavior and thus explain some of the settlement behavior of foraging societies (Mithen 1991; Smith 1991). In states and empires, we can use modern microeconomic theory to predict settlement, trade, and political organization. However, we have very little understanding of how to predict behavior in societies that fall between these two extremes. One of the basic assumptions of modern economic, geographical, and cultural ecological studies is that humans are energy maximizers. Ecologists view this ability to be economically efficient as a product of our evolutionary history of being adaptive (Jochim 1981; Krebs and Davies 1991; Smith and Winterhalder 1992; Stephens and Krebs 1986; Winterhalder and Smith 1981). Support for this assumption is clearly seen in studies of small, mobile foraging societies where individuals and kin-based groups tend to maximize their economic return with subsistence and settlement behaviors that most would agree are adaptive in that particular context (Jochim 1981; Mithen 1991; Smith 1991). For sedentary communities with more complex political organizations (tribes and simple chiefdoms), however, this is not the case, and this discrepancy is seen archaeologically in settlement and subsistence strategies that do not conform to predictions derived from optimal foraging theory. Thus, an underlying assumption in ecological studies is that models of subsistence economizing behavior and studies of subsistence efficiency will work well for hunters and gatherers (Keene 1981; Winterhalder and Smith 1981) or small-scale horticulturalists (Keegan 1986), but will decrease in their explanatory power with increasing social and political complexity. Although this has not been specifically tested, the fact that optimal foraging theory is less effective in explaining behavior in agricultural and sedentary hunter-and-gatherer societies (Maschner 1992) and is not usually applied to chiefdoms and states at all supports this contention.
EXPRESS information bases
Authors: Schenck Douglas , Wilson Peter
Published: November 2020

One of the assumptions underlying EXPRESS is that there is, somewhere, going to be an information base that contains instances of data corresponding to the information model. In this Chapter we examine aspects of this hypothetical information base. We also briefly note some of the software tools that could be useful when you are modeling using EXPRESS. We use the term information base in a very general sense; it is any repository that contains data corresponding to an EXPRESS (or EXPRESS-G) information model. The idea that probably comes to mind when hearing the term is that ‘an information base is a fancy name for a database.’ In our sense, an information base may be a database, but it may also be more than or less than a database. In fact, it may not even be computer-based at all! Some examples of information bases are: • Intelligent Knowledgebases • Knowledgebases • Databases • Computer files • Printed documents These examples are listed in approximately decreasing order of technical complexity and increasing order of technology age. Thus, intelligent knowledgebases are at, or even beyond, the leading edge of technology, while printed documents have been available for some centuries, although the technology for producing these has made dramatic strides over the last decade. Below we briefly describe various types of information bases, starting with databases. Knowledgebases are at the leading edge of the technology and are not treated; we merely note that there appears to be no fundamental reason why EXPRESS models should not be stored and instanced using this advanced technology. Databases provide a structured means of both storing data in a computer system and of querying the data in an efficient manner. Internally, the data may be structured in the form of a network, a hierarchy, or in tables following the relational model. Most new databases are relational, while older ones may be hierarchical or network based. Object-Oriented databases have recently appeared, but as yet there appears to be no consensus on exactly what an OODB is. Databases are designed so that they can be modified and queried by mutiple users.
EXPRESS-G models
Authors: Schenck Douglas , Wilson Peter
Published: November 2020

EXPRESS-G provides for two levels of modeling — a schema-level model and an entity-level model. Further, either of these may be complete or partial. This Chapter describes these various kinds of model. A schema-level model is one which displays the schemas, and the relationships between these schemas, that comprise an information model. The contents of the schemas (i.e., the entities, types, etc.) are not displayed. A schema level model, then, consists of: • The schemas that another schema Uses. • The schemas that another schema References. • The names of the things used and referenced. An example schema level model is shown in Figure 19.1. The Use relation is shown by a normal width relation line from the using schema to the used schema, with an open circle denoting the used schema end of the relationship line. The Reference relation is shown by a dashed relation line from the referencing schema to the referenced schema, with an open circle denoting the referenced schema end of the relationship line. The definitions used or referenced are shown as a list of names adjacent to the relevant relationship line, and connected to the relationship line by an arrowheaded line. If a definition is aliased, then this is indicated by following the original name of the definition by a ‘greater than’ (>) sign and the alias name. The model in Figure 19.1 consists of three schemas called fem, geom and mat. The fem schema Uses the property entity from the mat schema. It also References the point entity from the geom schema, and gives it the node alias. Schema-level models may be too large to fit on a single physical page. If this is the case then the page referencing symbols can be used to split the schema-schema relationship lines. The names of imported definitions should be on the same page as the importing schema symbol. An entity-level model is an EXPRESS-G model that represents the definitions and relationships that comprise a single schema. Thus, the components of such a model consist of type, entity and relationship symbols, together with role and cardinality information as appropriate.
The EXPRESS-I Language
Authors: Schenck Douglas , Wilson Peter
Published: November 2020

Now we turn to the question: ‘Once I have created an abstract declaration in EXPRESS, what would an instance of that thing look like?’ EXPRESS-I allows you to create instances of EXPRESS things that have values in place of references to datatypes. The main reason for doing this is to study some realistic examples of things that otherwise might be difficult to understand. After all, it is one thing to describe a tree and quite another to actually see one. Some of the design goals of EXPRESS-I are based on these requirements: • Major information modeling projects are large and complex. Managing them without appropriate tools based on formal languages and methods is a risky proposition. Informal specification techniques eliminate the possibility of employing computer automation in checking for inconsistencies in presentation or specification. • The language should focus on the display of the realization of the properties of entities, which are the things of interest. The definition of entities is in terms of data and behavior. Data represents the properties by which an entity is realized and behavior is represented by constraints. • The language should seek to avoid, as far as possible, specific implementation views. That is, EXPRESS-I models do not suggest the structure of databases, object bases, or of information bases in general. • The language should provide a means for displaying small populated models of EXPRESS schemas as examples for design reviews. • The language should provide a means for supporting the specification of test suites for information model processors. EXPRESS-I represents entity instances in terms of the values of its attributes (attributes are the traits or characteristics considered important for use and understanding). These values have a representation which might be considered simple (an integer value) or something more complex (an entity value). A geometric point might be defined in terms of three real numbers named x, y and z, and the actual values associated with those attributes might be 1.0, 2.5 and 7.9. The EXPRESS-I instance language provides a means of displaying instantiations of EXPRESS data elements. The language is designed principally for human readability and for ease of generating EXPRESS-I element instances from definitions in an EXPRESS schema.
Usage notes
Authors: Schenck Douglas , Wilson Peter
Published: November 2020

Now we discuss some of the potential uses of the EXPRESS-I language. In Object-Oriented terms, an EXPRESS entity would be called a class, and an instance of a class is termed an object. One object may reference another object. EXPRESS, though, distinguishes between entities and types (i.e., the enumeration, select and the defined data type) as entities may be subtyped whereas types cannot be. EXPRESS-I treats entity instances as objects in the OO sense. It also allows types to be treated as objects in that they can be instantiated and referenced. Alternatively, type values may be embedded in entity instances. The simplest use of EXPRESS-I is as a paper exercise in displaying examples of EXPRESS declarations that are populated with data. The language allows the display of entity instances as referenceable objects. Types instances may also be displayed as referenceable objects, or they may appear as unreferenceable values within other objects' values. Examples in this book show both forms of type instantiation. Values of explicit entity attributes are required. The values of derived or inverse attributes need not be displayed, except as exemplars, because as noted, these are essentially calculable from the values of the explicit attributes. Examples of EXPRESS schemas can also be displayed, as well as individual objects. The EXPRESS-I model construct is provided to enable the display of multiple schemas. Typically, a model would be used when two or more EXPRESS schemas interact with each other. Note that EXPRESS itself does not support such a construct. Note: We do not discuss models in this book. The test case construct is provided to assist in the formal specification of test cases against the implementation of an EXPRESS schema. EXPRESS itself does not provide an equivalent construct. For a test case, a base set of EXPRESS-I objects must be defined which will be the objects (and their supporting data) to be tested. The values of these objects may be in the form of parameters, whose formal definition are given in an enclosing context. A series of test cases may then be defined on the context, by providing actual parameter values.
Parallel Computing Using the Prefix Problem
Authors: Lakshmivarahan S. , Dhall Sudarshan K.
Published: November 2020

The prefix operation on a set of data is one of the simplest and most useful building blocks in parallel algorithms. This introduction to those aspects of parallel programming and parallel algorithms that relate to the prefix problem emphasizes its use in a broad range of familiar and important problems. The book illustrates how the prefix operation approach to parallel computing leads to fast and efficient solutions to many different kinds of problems. Students, teachers, programmers, and computer scientists will want to read this clear exposition of an important approach.
Preliminaries
Authors: Schmickler Wolfgang
Published: November 2020

In this chapter we introduce and discuss a number of concepts that are commonly used in the electrochemical literature and in the remainder of this book. In particular we will illuminate the relation of electrochemical concepts to those used in related disciplines. Electrochemistry has much in common with surface science, which is the study of solid surfaces in contact with a gas phase or, more commonly, with ultrahigh vacuum (uhv). A number of surface science techniques has been applied to electrochemical interfaces with great success. Conversely, surface scientists have become attracted to electrochemistry because the electrode charge (or equivalently the potential) is a useful variable which cannot be well controlled for surfaces in uhv. This has led to a laudable attempt to use similar terminologies for these two related sciences, and to introduce the concepts of the absolute scale of electrochemical potentials and the Fermi level of a redox reaction into electrochemistry. Unfortunately, there is some confusion of these terms in the literature, even though they are quite simple. Electrochemical interfaces are sometimes referred to as electrified interfaces, meaning that potential differences, charge densities, dipole moments, and electric currents occur. It is obviously important to have a precise definition of the electrostatic potential of a phase. There are two different concepts. The outer or Volta potential ψα of the phase a is the work required to bring a unit point charge from infinity to a point just outside the surface of the phase. By "just outside" we mean a position very close to the surface, but so far away that the image interaction with the phase can be ignored; in practice, that means a distance of about 10-5 — 10-3 cm from the surface. Obviously, the outer potential ψα is a measurable quantity. In contrast, the inner or Galvani potential ϕα is defined as the work required to bring a unit point charge from infinity to a point inside the phase α; so this is the electrostatic potential which is actually experienced by a charged particle inside the phase. Unfortunately, the inner potential cannot be measured: If one brings a real charged particle - as opposed to a point charge - into the phase, additional work is required due to the chemical interaction of this particle with other particles in the phase. For example, if one brings an electron into a metal, one has to do not only electrostatic work, but also work against the exchange and correlation energies.
Selected experimental results for electron-transfer reactions
Authors: Schmickler Wolfgang
Published: November 2020

Innumerable experiments have been performed on both inner- and outer-sphere electron-transfer reactions. We do not review them here, but present a few results that are directly relevant to the theoretical issues raised in the preceding chapters. The Butler-Volmer equation (5.10) predicts that for |η| > kT/e0 a plot of the logarithm of the current versus the applied potential (Tafel plot) should result in a straight line, whose slope is determined by the transfer coefficient α. Because of the dual role of the transfer coefficient (see Section 5.2), it is important to verify that the transfer coefficient obtained from a Tafel plot is independent of temperature. We shall see later that proton- and ion-transfer reactions often give straight lines in Tafel plots, too, but the apparent transfer coefficient obtained from these plots can depend on the temperature, indicating that these reactions do not obey the Butler-Volmer law. In order to test the temperature independence of the transfer coefficient, Curtiss et al. investigated the kinetics of the Fe2+/Fe3+ reaction on gold in a pressurized aqueous solution of perchloric acid over a temperature range from 25° to 75°C. In the absence of trace impurities of chloride ions, this reaction proceeds via an outer sphere mechanism with a low rate constant (k0 ≈ 10-5 cm s-1 at room temperature). Figure 8.1 shows the slope of their Tafel plots, d(lni)/dη, as a function of the inverse temperature 1/T. The Butler-Volmer equation predicts a straight line of slope αe0/k, which is indeed observed. Over the investigated temperature range both the transfer coefficient and the energy of activation are constant: α = 0.425 ± 0.01 and Eact = 0.59± 0.01 eV at equilibrium, confirming the validity of the Butler-Volmer equation in the region of low overpotentials, from which the Tafel slopes were obtained. The phenomenological derivation of the Butler-Volmer equation is based on a linear expansion of the Gibbs energy of activation with respect to the applied overpotential. At large overpotentials higher-order terms are expected to contribute, and a Tafel plot should no longer be linear.
Charge distribution in Adsorbates
Authors: Schmickler Wolfgang
Published: November 2020

The distribution of charges on an adsorbate is important in several respects: It indicates the nature of the adsorption bond, whether it is mainly ionic or covalent, and it affects the dipole potential at the interface. Therefore, a fundamental problem of classical electrochemistry is: What does the current associated with an adsorption reaction tell us about the charge distribution in the adsorption bond? In this chapter we will elaborate this problem, which we have already touched upon in Chapter 4. However, ultimately the answer is a little disappointing: All the quantities that can be measured do not refer to an individual adsorption bond, but involve also the reorientation of solvent molecules and the distribution of the electrostatic potential at the interface. This is not surprising; after all, the current is a macroscopic quantity, which is determined by all rearrangement processes at the interface. An interpretation in terms of microscopic quantities can only be based on a specific model. There is a formal similarity between adsorption and reactions such as metal deposition which gives rise to the concept of electrosorption valence. Consider the deposition of a metal ion of charge number z on an electrode of the same material.
Introduction and Related Research
Authors: Graf William L.
Published: November 2020

Plutonium occurs throughout the earth’s environmental systems, though usually in quantities so small that they are barely detectable. Because this artificial element is so toxic, it is necessary to identify those few locations where the concentrations are likely to be the highest. Because almost all plutonium released into the environment is ultimately attached to soil and sediment particles, the behavior of constantly changing natural transport systems such as water and sediment flows provide the key to understanding the ultimate geographic disposition of the element. The general purpose of the work discussed in this book is to explain the distribution of plutonium in the Northern Rio Grande system of northern New Mexico and southwestern Colorado by forging a link among the available data and general principles of environmental sciences such as hydrology, geomorphology, and radioecology. Between 1945 and 1952, Los Alamos National Laboratory handled large amounts of plutonium as part of the Manhattan Project (the effort to construct the first atomic weapons) and as part of the weapons programs related to the early years of the cold war. During this time, the laboratory emptied untreated plutonium waste into the alluvium of Los Alamos Canyon. After 1952, the laboratory released relatively small amounts of treated plutonium waste. Although the vertical movement of plutonium through the alluvial materials has been largely limited to the upper 10 m,4 the horizontal movement of the contaminants has had much larger dimensions. The plutonium was adsorbed onto sedimentary particles, and so the fate of those sediments is also the fate of the plutonium. Natural processes of erosion have resulted in substantial movement of contaminated sediments through the canyons. Research during the 1960s and early 1970s showed that since the war years, surface flows within the laboratory’s boundaries had redistributed at least some of plutonium. Laboratory researchers later estimated that fluvial (river-related) processes in Los Alamos Canyon had probably removed significant quantities from the laboratory area by carrying the plutonium into the Rio Grande. They predicted that early in the twenty-first century almost all of the plutonium would have been emptied from Los Alamos Canyon into the Rio Grande.
Annual Plutonium Budget for the Rio Grande
Authors: Graf William L.
Published: November 2020

A mean annual plutonium budget for the Northern Rio Grande provides an accounting of the amounts of plutonium moving into and out of various reaches of the river during a typical year. Such a budget is a basis for assessing the rates of plutonium transport and the location of storage along the river. The budget presented in the following pages is for bedload and suspended sediments. It does not include plutonium in water because water-borne plutonium is such a small portion of the total in the system (as discussed in Chapter 7). The budget as calculated here requires data concerning sediment and plutonium concentrations in the sediment. The sediment discharge data that are available from U. S. Geological Survey gaging sites (Chapter 4) define the overall framework for budget construction. A reasonably detailed picture is possible for the river system from the Rio Grande at Embudo and the Rio Chama at Chamita southward to the Rio Grande at San Marcial (for locations, see Figure 3.9) where the river empties into Elephant Butte Reservoir. Data collected by Los Alamos National Laboratory and published in the annual surveillance reports by the laboratory’s Environmental Studies Group and later by the Environmental Surveillance Group provide plutonium concentrations for bedload and suspended sediments. The calculations for each site in this study used mean values of plutonium concentrations from all measurements at or near the site. Table 8.1 reviews the sources of plutonium concentration data for each of the sediment-gaging sites in the regional budget calculations. Unfortunately, the sites for collecting the plutonium data were not always colocated with the gaging sites that produced the sediment discharge data. In addition, most of the plutonium concentration data are for bedload sediments because of the manner in which the workers collected samples. In some cases, the best estimates of plutonium concentrations in suspended load for gaging sites are from concentrations found in sediments of the nearest reservoir downstream because those sediments are likely to have been in suspension before their emplacement on reservoir floors. The assumption that the mean concentration is a useful representative value seems reasonable given that in those reaches with relatively large amounts of data, concentration values do not show temporal or geographic trends.
Privatizing Public Lands
Authors: Lehmann Scott
Published: November 2020

In the United States, private ownership of land is not a new idea, yet the federal government retains title to roughly a quarter of the nation's land, including national parks, forests, and wildlife refuges. Managing these properties is expensive and contentious, and few management decisions escape criticism. Some observers, however, argue that such criticism is largely misdirected. The fundamental problem, in their view, is collective ownership and its solution is privatization. A free market, they claim, directs privately owned resources to their most productive uses, and privatizing public lands would create a free market in their services. This timely study critically examines these issues, arguing that there is no sense of "productivity" for which it is true that greater productivity is both desirable and a likely consequence of privatizing public lands or "marketizing" their management. Lehmann's discussion is self-contained, with background chapters on federal lands and management agencies, economics, and ethics, and will interest philosophers as well as public policy analysts.
Federal Lands, Past and Present
Authors: Lehmann Scott
Published: November 2020

How did the federal government end up with title to a quarter of the land in a nation with a long-standing distrust of government power, a corresponding faith in individual enterprise, and democratic institutions designed to make government policies reflect its will? While explanation is not justification, an account of their evolution can help make some sense of current federal land policies. In this chapter, I outline the history of federal lands and the shape of the current management regime, indicating what agencies are responsible for what lands under what statutory charters. Readers familiar with these topics will find nothing new here and may wish to skip to the concluding observations. The federal government got into the real-estate business early on. Through a political compromise between the original states, it acquired the old “western lands” between the Appalachians and the Mississippi. During the colonial period, England had rather imprecisely divided the land it claimed in America among its colonies. Charters granted extensive lands beyond the Appalachians to some colonies, sometimes the same lands to different colonies. Connecticut and Massachusetts, for example, claimed the same 26 million acres in the old Northwest (north of the Ohio River, west of the Appalachians). England revoked some of these grants in 1774, but colonies thereby severed from their western lands regarded the War of Independence as a means to regain what had been theirs. States with no historical claims to press wanted to share in what they considered war booty “wrested from the common enemy by the blood and treasure of the thirteen states.” They proposed that the western lands be surrendered to the federal government “to be disposed of for the common good of the United States.” Maryland feared that otherwise it would have to make good on promises of land in exchange for service in the Revolution that the Continental Congress had made to Maryland troops. For the same reason, the national government, such as it was, promoted state cession of western lands: nobody relished the prospect of angry veterans marching on Congress to demand the land they’d been promised.
Reaction Dynamics in Femtosecond and Microsecond Time Windows: Ammonia Clusters as a Paradigm
Authors: Wei S. , Castleman A. W. , Jr
Published: November 2020

The last decade has seen tremendous growth in the study of gas phase clusters. Some areas of cluster research which have received considerable attention in this regard include solvation (Lee et al. 1980), (Armirav et al. 1982), and reactivity (Dantus et al. 1991; Khudkar and Zewail 1990; Rosker et al. 1988; Scherer et al. 1987). In particular, studies of the dynamics of formation and dissociation, and the changing properties of clusters at successively higher degrees of aggregation, enable an investigation of the basic mechanisms of nucleation and the continuous transformation of matter from the gas phase to the condensed phase to be probed at the molecular level (Castleman and Keesee 1986a, 1988). In this context, the progressive clustering of a molecule involves energy transfer and redistribution within the molecular system, with attendant processes of unimolecular dissociation taking place between growth steps (Kay and Castleman 1983). Related processes of energy transfer, proton transfer, and dissociation are also operative during the reorientation of molecules about ions produced during the primary ionization event required in detecting clusters via mass spectrometry (Castleman and Keesee 1986b), providing further motivation for studies of the reaction dynamics of clusters (Begemann et al. 1986; Boesl et al 1992; Castleman and Keesee 1987; Echt et al. 1985; Levine and Bernstein 1987; Lifshitz et al. 1990; Lifshitz and Louage 1989, 1990; Märk 1987; Märk and Castleman 1984, 1986; Morgan and Castleman 1989; Stace and Moore 1983; Wei et al. 1990a,b). The real-time probing of cluster reaction dynamics is a facilitating research field through femtosecond pump-probe techniques pioneered by Zewail and coworkers (Dantus et al. 1991; Khundkar and Zewail 1990; Rosker et al. 1988; Scherer et al. 1987). Some real-time investigations have been performed on metal, van der Waals, and hydrogen-bonded clusters by employing these pump-probe spectroscopic techniques. For example, the photoionization and fragmentation of sodium clusters have been investigated by ion mass spectrometry and zero kinetic energy photoelectron spectroscopy in both picosecond (Schreiber et al. 1992) and femtosecond (Baumert et al. 1992, 1993; Bühler et al. 1992) time domains. Studies have also been made to elucidate the effect of solvation on intracluster reactions.
Magic Numbers, Reactivity, and lonization Mechanisms in ArnXm Heteroclusters
Authors: Vaidyanathan Gopalakrishnan , Garvey James F.
Published: November 2020

During the past decade, there has been an enormous increase in experimental and theoretical studies directed toward obtaining a fundamental understanding of the properties of van der Waals (vdW) clusters (Castleman 1990; Castleman and Keesee 1986b, 1988b; Garvey et al. 1991; Goyal et al. 1993; Janda 1985; Jortner 1984; Levy 1981; Märk 1987; Märk and Castleman 1985; Ng 1983; Stace 1992). As the term "cluster" is frequently used in the scientific community with different connations, it would be appropriate to define "cluster" in the context of this field. Gas phase clusters are defined as finite gas phase aggregates composed of two to several million components (i.e., atoms or molecules). These species are held together by different types of forces, ranging from the weak van der Waals forces all the way up to strong electrostatic forces. A techique of classifying clusters based on the type of the binding forces has been developed. Another convenient basis for the classification of clusters is according to the size, such that clusters with n = 2-10 or 13 have been termed microclusters, clusters with n = 10-102 have been referred to as small clusters, and aggregates with n ≥ 102 are called large clusters (Jortner 1984). Clusters composed of a few molecules can be treated, to a first approximation, as isolated gas phase species, while clusters with sizes n > 103 begin to exhibit properties resembling those of condensed or bulk materials. Between these two extremes lies the regime where cluster systems cannot be adequately treated by either the molecular concepts or the conventional solid-state approach. Thus, clusters have previously been described as the conceptual bridge linking the gas and the condensed phases (bulk liquids or solids) (Castleman 1990; Castleman and Keesee 1986b, 1988b; Garvey et al. 1991; Goyal et al. 1993; Janda 1985; Jortner 1984; Levy 1981; Märk 1987; Märk and Castleman 1985; Ng 1983; Stace 1992).
Landscape with Figures
Authors: Anderson E. N.
Published: November 2020

So wrote Edward Fitzgerald, following (loosely) the Persian of Omar Khayyám. In this quatrain, he captured what may be the most universal and constant yearning of humankind. Modern psychology has shown what many of us always suspected: humans continually, in the secrecy of their thoughts, do exactly what Fitzgerald wished. The external world is all too refractory, but “the soul is free.” Thus, humans often see what they want to see, and believe about it what they wish to believe. The external world may intrude harshly on this process, but people often show a truly instructive ability to shut out reality. Positive illusions are only one of the ways we distort information. The human brain is a wondrous device—partly because it does not produce a perfect, total representation of what the senses perceive. We are constantly reinterpreting those perceptions in terms of our wants and needs—not only needs for things like food and shelter, but also needs to see the world as hopefully as possible, to see it as simple and comprehensible, and to see it as ultimately manageable. The brain quite literally does shatter perception “to bits, and then remold it closer to the heart’s desire.” The world environmental problem is serious, and getting steadily more so. Part of the reason is that humans have seen what they wanted to see and have deliberately blinded themselves to the less desirable consequences of their actions. The built-in human tendency to see the world through rose-colored glasses has received the name “positive illusions” from social psychologist Shelley Taylor. She points out the advantages of positive illusions. They allow us to face a threatening world. However, positive illusions have their costs. It is, at the best of times, hard to get people to sacrifice short-term interests for longterm benefits. Positive illusions make it even harder. Such habits of mind lie behind much of the world’s pollution, species extinction, deforestation, overfishing, soil erosion, and famine. Political remedies have failed. The vaunted Rio de Janeiro conference of 1992 was disappointing.
Beyond Programming
Authors: Blum Bruce I.
Published: November 2020

This book provides a unique examination of the software development process, arguing that discipline, still dominated by methods conceived in the framework of older technologies, must undergo a fundamental reexamination of its guiding principles in order for significant progress to take place. To gain fresh insights into how we ought to direct future research, the author begins with a search for first principles. The book begins with an exploration of the scientific foundations of computer technology, then examines design from the perspective of practitioners. The book also offers a critique of the methods employed in software development and an evaluation of an alternate paradigm that has been used successfully for 14 years. The concepts reviewed here comprise a set of core readings for understanding the research and development challenges that will confront computer technology in the 21st century and will be of great interest to computer science researchers and educators, graduate students, and software engineers.
Paths Across the Levee
Authors: Worster Donald
Published: November 2020

In 1821 a man came exploring across the prairies and plains of the North American continent. His name was Jacob Fowler, and with his companions he would be the first Euro-American to ascend the whole length of the Arkansas River from what is now Fort Smith, Arkansas, to the Rocky Mountains. After eight days of poling against the current, “we stoped,” he writes in his untutored spelling, “at the mouth of a bold sreem of Watter” emptying into the Arkansas, a tributary about seventy feet wide. They followed that stream north through the sand hills that cover part of present-day Reno and Rice counties in the state of Kansas. Only a few cottonwood trees grew along its banks, affording scant shelter from the big sky, but the bluestem grass was so high one could not see the river ahead as it meandered across the prairie. Beyond the rich moist bottomlands the vegetation became buffalo grass, and the bison grazed there in black, drifting multitudes; the local Indians called the stream after the female bison, a name that became “Cow Creek” in the white man’s tongue. There were pronghorn antelopes in those days, so light and agile, counterpointing the shaggy herds. Fowler and his crew might also have seen deer, elk, coyotes, and dense flocks of ducks and geese. Then, their curiosity satisfied and their senses pleased, they pushed on west. Fowler had no idea that almost three centuries earlier another European, Don Francisco Vásquez de Coronado, had come here from the opposite direction, crossing this very same Cow Creek on his quest for the fabled city of Quivira. Coronado found in the vicinity only the Wichita Indians living in domed huts thatched with grass, but he did remark that . . . the country itself is the best I have ever seen for producing all the products of Spain, for besides the land itself being very fat and black, and being very well watered by the rivulets and springs and rivers, I found prunes like those of Spain and nuts and very good sweet grapes and mulberries. . . .
Restoring a Natural Order
Authors: Worster Donald
Published: November 2020

A few years ago I came down a backcountry road in Wisconsin looking for a place where a man had given his life. The road had once been the route of pioneers moving west, then a farm road running through dry, sandy, marginal fields. In the days of Prohibition it had carried illegal whiskey distilled hereabouts, some of the last trees having been cut down to cook the bootlegger’s brew. Then in 1935 another sort of settler came along. It was the time of the Great Depression, and he could buy a lot of land, 120 acres in all, land abandoned by its owners, for a little money in back taxes. The land had no economic value left in it. The man, whose name was Aldo Leopold, knew that but did not mind; he was not after gain or even subsistence. He began coming out regularly from the city of Madison, where he taught at the university, to plant trees. For thirteen years he planted and nurtured. Then, in 1948, he died fighting a forest fire on a neighbor’s land. Knowing those few details, I came wanting to know what manner of man he was and what he had died for. There was no publicity, no tour guide provided, but the dense forest of pines was a sufficient announcement that here was Leopold’s place, now all grown up again to natural splendor. I walked through an open field rich in wild grasses and forbs to a small, gray, weathered shack where he had stayed on those weekends, regaled by the smell of his new pines coming up and the sound of birdsong and wind in their branches. From the shack, I found my way down a short path to the Wisconsin River, rolling silently between its pungent banks, the warm summer sun glinting on its ripples. One August years ago Leopold, as recalled in a sketch he wrote and collected in A Sand County Almanac, found the river “in a painting mood,” laying down a brief carpet of moss on its silty edges, spangling it with blue and white and pink flowers, attracting deer and meadow mice, then abruptly scouring its palette down to austere sand.
The Electrical Double Layer
Authors: Fawcett W. Ronald
Published: November 2020

In examining the properties of the metal | solution interface, two limiting types of behavior are found, namely, the ideal polarizable interface and the ideally nonpolarizable interface. In the former case, the interface behaves as a capacitor so that charge can be placed on the metal using an external voltage source. This leads to the establishment of an equal and opposite charge on the solution side. The total system in which charge is separated in space is called the electrical double layer and its properties are characterized by electrostatic equilibrium. An electrical double layer exists in general at any interface at which there is a change in dielectric properties. It has an important influence on the structure of the interface and on the kinetics of processes occurring there. The classical example of an ideally polarizable interface is a mercury electrode in an electrolyte solution which does not contain mercury ions, for example, aqueous KCl. The charge on the mercury surface is altered using an external voltage source placed between the polarizable electrode and non-polarizable electrode, for example, a silver | silver chloride electrode in contact with the same solution. Within well-defined limits, the charge can be changed in both the negative and positive directions. When the mercury electrode is positively charged, there is an excess of anions in the solution close to the electrode. The opposite situation occurs when the electrode is negatively charged. An important point of reference is the point of zero charge (PZC), which occurs when the charge on the electrode is exactly zero. The properties of the electrical double layer in solution depend on the nature of the electrolyte and its concentration. In many electrolytes, one or more of the constituent ions are specifically adsorbed at the interface. Specific adsorption implies that the local ionic concentration is determined not just by electrostatic forces but also by specific chemical forces. For example, the larger halide ions are chemisorbed on mercury due to the covalent nature of the interaction between a mercury atom and the anion. Specific adsorption can also result from the hydrophobic nature of an ion.
Preservation Paradigms and Tropical Rain Forests
Authors: Kramer Randall A. , van Schaik Carel P.
Published: November 2020

Tropical rain forests are disappearing rapidly as a result of increasing human encroachment. During the past century, tropical rain forests have been reduced to about half of their original area. And the rate of deforestation is accelerating, fueled by population growth in developing countries and resource demands in the developed countries. The remaining forests are subject to increasingly intensive human use. Deforestation, fragmentation, and exploitation cause a plethora of problems, including soil erosion; siltation of rivers, lakes, and estuaries; increased flooding and droughts; release of carbon dioxide and other greenhouse gases into the atmosphere; and loss of species. In recent years, these problems have become the subject of international concern. This book focuses on the loss of biodiversity in tropical rain forests and on the role of protected areas in stemming the loss. This chapter examines the meaning of biodiversity and the history of the park movement in the tropics. What began as protection of habitat through the exclusion of people has transformed into sustainable use of biological resources. This new emphasis provides local control of important resources and greater income, but does it conserve habitat and species? We will argue that a renewed focus on protected areas as the primary storehouse of biodiversity is needed. We will also make the case for a focus on the tropical rain forest biome and will conclude with an overview of the rest of the book. In its strict sense, biodiversity refers to the “variety and variability among living organisms and the ecological complexes in which they occur” (Office of Technology Assessment, U.S. Congress, 1987:3). This definition can be extended both downward to cover genetic variability within a species and upward to include habitat and ecosystem diversity. practical terms, however, biodiversity is most profitably expressed as species diversity (weighted for rarity, endemism, and taxonomic distinctiveness, if necessary) at the landscape level (see chapter 6). We adopt this definition of biodiversity. During the past few years, attempts to link rain forest protection with sustainable development have led to a noticeable expansion of the meaning of the phrase “biodiversity conservation.”