bluuebunny/crossref_metadata_2025 huggingface dataset:
Organic Matter and Nutrients in the Mainstem Amazon River
Authors: Devol Allan H. , Hedges John I.
Published: November 2020

The Amazon, like smaller rivers, is the daughter of its drainage basin. Local climate and interactions over time with the template of topography, geology, and vegetation determine the size and flow of rivers. Likewise, the compositions of the particulate and dissolved materials carried by rivers result from initially similar rainwaters that have been uniquely imprinted by contact with almost every plant, animal, and mineral in the catchment. Rivers thus provide a continuously flowing signal, recorded by isotopes, ions and molecules, of the cumulative effects of drainage basin processes such as weathering, oxidation/reduction, gas exchange, photosynthesis, biodegradation, and partitioning. This recording is complementary to more classical methods of remote sensing based on electromagnetic radiation, but is composited over a wider range of time and space scales and includes effects of subcanopy and subsurface processes. The Amazon River is similar to other rivers in this regard, but is unusual in the size and extent of different environments its waters touch. The Amazon River is the world’s largest river and drains the world’s largest single catchment (∼6,000,000 km2). It discharges an average of about 200,000 m3 of water per second to the Atlantic Ocean. This volume is about 5 times more than the Congo, the second largest river. The Amazon has 1100 major tributaries, three of which are nearly as large as the Congo. From its origins at about 5200 m in the Andes about 200 km from the Pacific Ocean, the Amazon goes through at least 10 name changes as it snakes its way 6500 km eastward to the Atlantic Ocean (Schreider and Schreider 1970). The flooded areas along the lower mainstem are important sources of greenhouse gases such as methane (Bartlett and Harriss 1993, Devol et al. 1994) and the latent heat release from convective precipitation in the basin is sufficient to influence global climate. The Amazon drainage basin contains 40% of the world’s tropical rain forest (dos Santos, 1987) and is home to countless species of plants and animals. The river itself contains some 2000 described species of fish.
Properties and Management of Oxidic Soils
Authors: Juo Anthony S. R. , Franzluebbers Kathrin
Published: November 2020

Oxidic soils are deeply weathered, fine-textured, oxide-rich soils in the tropics. These soils are the second most abundant soils in the tropics. Geographically, oxidic soils are found in Latin America (Brazil, Central America), East and Central Africa (Kenya, Congo, and Cameroon), the Caribbean Basin, and the Pacific Islands. In southeastern Asia, oxidic soils are found in isolated areas of Indonesia, the Philippines, and northern Australia, usually on the volcanic and limestone-dominated geomorphic surfaces. Oxidic soils are oxide-rich, low bulk density Oxisols, Alfisols, and Ultisols according to the Soil Taxonomy classification. In other soil classification schemes, most oxidic soils are classified under Sols Ferallitiques according to the French system, and Ferralsols and Nitosols under the FAO/UNESCO system. Oxidic soils are differentiated into high-base-status and low-base-status soils on the basis of the 70% base saturation limit calculated from effective CEC. The high-base-status oxidic soils generally are enriched with Ca-saturated organic matter in the surface layer and are among the more productive upland soils in the tropics. The low-base-status oxidic soils are acidic, have a low effective CEC, and the degree of exchangeable Al saturation often exceeds 60% in the subsoil horizons. Because of their excellent soil physical properties, oxidic soils are more resistant to soil erosion and therefore better suited to large-scale mechanized agriculture than kaolinitic soils. Although the dominant clay mineral is kaolinite, the presence of moderate amounts of crystalline and amorphous Fe and Al oxides and hydrous oxides (around 5% Fe2O3 or higher) with a high specific surface area (100 m2/g or larger) gives rise to many unique chemical and physical properties, such as a variable surface charge, the formation of microaggregates, low bulk density (0.8-1.2 Mg/ m3), stable soil structure, and high permeability. Most oxidic soils are red or dark red due to the presence of clay-size hematite (Fe2O3) in the soil. The yellowish oxidic soils contain primarily goethite (FeOOH) in the clay fraction and occur in the wetter geomorphic positions of a deeply weathered landscape. Extensive areas of clayey, yellowish oxidic soils are found in the Amazon Basin. Gibbsite (A1OOH) is the major crystalline Al oxide.
Properties and Management of Allophanic Soils
Authors: Juo Anthony S. R. , Franzluebbers Kathrin
Published: November 2020

Allophanic soils are dark-colored young soils derived mainly from volcanic ash. These soils typically have a low bulk density (< 0.9 Mg/m3), a high water retention capacity (100% by weight at field capacity), and contain predominantly allophanes, imogolite, halloysite, and amorphous Al silicates in the clay fraction. These soils are found in small, restricted areas with volcanic activity. Worldwide, there are about 120 million ha of allophanic soils, which is about 1% of the Earth's ice-free land surface. In tropical regions, allophanic soils are among the most productive and intensively used agricultural soils. They occur in the Philippines, Indonesia, Papua New Guinea, the Caribbean and South Pacific islands, East Africa, Central America, and the Andean rim of South America. Allophanic soils are primarily Andisols and andic Inceptisols, Entisols, Mollisols, and Alfisols according to the Soil Taxonomy classification. Allophanic soils generally have a dark-colored surface soil, slippery or greasy consistency, a predominantly crumb and granular structure, and a low bulk density ranging from 0.3 to 0.8 Mg/m3. Although allophanic soils are apparently well-drained, they still have a very high water content many days after rain. When the soil is pressed between fingers, it gives a plastic, greasy, but non-sticky sensation of a silty or loamy texture. When dry, the soil loses its greasiness and becomes friable and powdery. The low bulk density of allophanic soils is closely related to the high soil porosity. For example, moderately weathered allophanic soils typically have a total porosity of 78%, with macro-, meso-, and micropores occupying 13%, 33%, and 32%, respectively. Water retained in the mesopores is readily available for plant uptake. Water retained in the micropores is held strongly by soil particles and is not readily available for plant use. The macropores provide soil aeration and facilitate water infiltration. The high water retention capacity is also associated with the high soil porosity. In allophanic soils formed under a humid climate, especially those containing large amounts of allophane, the moisture content at field capacity can be as high as 300%, calculated on a weight basis. Such extremely high values of water content seem misleading.
Relative Prices
Authors: Rostow W. W.
Published: November 2020

In viewing the time ahead, especially the next quarter century, I have been inclined to conclude that the industrial progress of India, China, Southeast Asia, and the major countries of Latin America are likely to produce a phase of rising prices in foodstuffs and raw materials and increased outlays to deal with the forces of environmental degradation. It is my hypothesis that for a time, in the early part of the 21st century, these developments will outstrip the deceleration of population. The more or less regular occurrence of such phases of demand pressure has marked the story of the world economy since the end of the 18th century. At least since about 1789, there have been successive periods when foodstuffs and raw materials were expensive and then cheap, relative to manufactured goods. From 1789 to 1920, these periods lasted about 25 years. After 1920, the cycles were much less regular and were significantly affected by wars, by the successive rise in the importance of oil, by outlays to preserve the environment, and finally by the involvement more directly of politics in the setting of basic prices. But economic historians are likely to agree that the period 1789-1914 was marked by two-and-a-half long relative-price cycles in raw material versus manufactured goods (see Figure 4.1). Although he had several predecessors, N. D. Kondratieff, a Russian economist who was immortalized by Joseph Schumpeter as the discoverer of the Kondratieff cycle or long wave, identified, dated, and discussed analytically this long cycle in the interwar years. He died in one of Joseph Stalin's labor camps in Siberia. The approximate dates and length of these long cycles through 1920 are shown in Table 4.1. The successive phases of falling and rising relative prices continued to follow one another despite two world wars, a pathological interwar period, and an unexpected postwar recovery, illustrated in Table 4.2. The peak of the early 1980s came in the second quarter of 1982 (or, on an annual basis, in 1981).
Introduction: Historical Perspective and Significance of Alpine Ecosystem Studies
Authors: Bowman William D.
Published: November 2020

Alpine tundra is an intriguing ecosystem—for its beauty as well as for the harsh climate in which it exists. Contrasted against jagged rock precipices and snow and ice and subjected to rapid changes in weather, the tundra, with its proliferation of diminutive flowers, appears deceptively fragile. John Muir, in detailing the alpine of the Sierra Nevada, was at a loss to adequately describe “the exquisite beauty of these mountain carpets as they lie smoothly outspread in the savage wilderness” (Muir 1894). Despite this aesthetic fascination for the alpine, it is one of the least studied ecosystems in the world. Significant effort has been expended to describe the physiological ecology of alpine organisms (e.g., Bliss 1985; Carey 1993; Körner 1999) and community patterns (Komárková 1979; Billings 1988), but there have been no syntheses detailing alpine ecosystem processes and patterns to the degree that they have been described in the arctic (e.g., Chapin 1992) and forest (e.g., Likens and Bormann 1995) ecosystems. The goal of this book is to provide a description of the Niwot Ridge/Green Lakes Valley alpine ecosystem of the Front Range in the Colorado Rocky Mountains, including the spatial and temporal patterns of animals, plants, and microorganisms and the associated ecosystem processes. The book focuses on the strengths of the research carried out on Niwot Ridge during the past four decades, particularly physical factors influencing alpine ecology (climate and geomorphology), patterns and functions of the vegetation, and N biogeochemistry. While the book focuses on a particular site, the results can be extrapolated to much of the southern and central Rocky Mountains, and thus it pertains to a broader geographic and scientific scope and will be of direct interest to ecologists in general as well as to those interested in ecosystems in extreme environments. There are numerous justifications for a synthesis of alpine ecosystem studies. While alpine tundra occupies only about 3% of the global land surface (Körner 1995) and thus has little impact on atmosphere-biosphere exchange, its presence at the extreme climatic tolerance for many organisms and its presence on every continent make it a good “indicator” system for regional environmental change.
Vertebrates
Authors: Armstrong David M. , Halfpenny James C.
Published: November 2020

Vertebrates of alpine tundra are near the limits of their genetic tolerance, and thus the alpine provides a natural laboratory for the study of the ecology of these organisms in a climatically stressful environment. The alpine supports a greater species richness of vertebrate herbivores than does arctic tundra (Halfpenny and Southwick 1982). Hoffmann (1974) provided an extensive review of terrestrial vertebrates of arctic and alpine ecosystems, emphasizing circumpolar patterns. For a variety of reasons, however, vertebrates of alpine tundra are considerably less studied than are those of the Arctic, and much remains to be learned about the physiological and behavioral adaptations of vertebrates that allow this group to exist in this extreme and variable ecosystem. May (1980) offered some generalizations about the state of knowledge of alpine animals. Terrestrial systems are better known than aquatic systems; the magnitude of environmental variability is better known than its predictability and significance to populations of animals; life histories of animals are better known than their roles and functions; dynamics of single species are better known than interactions between and among species; habitat selection by animals is more often defined in terms of the perception of the investigator than in terms of the perception of the organism; the response of animals to patterns of vegetation is better known than the influence animals have in creating and maintaining those patterns; and densities of animals are better known than are patterns of dispersion and their causes. Those generalizations remain broadly accurate. The purpose of this chapter is to develop a perspective on the structure and function of the vertebrate fauna of alpine environments of the Southern Rocky Mountains, with an emphasis on the fauna found on Niwot Ridge. It considers the origin and ongoing development of the fauna and its biogeographic and ecological relationships. A pattern of distributions is described that is dynamic in space and time. A principal focus is the role of vertebrates to the structure and function of the tundra ecosystem, including both the biotic and physical impacts of vertebrate populations. Some attention is paid to vertebrate trophic guilds, but plant-animal interactions are detailed in this volume by Dearing (chapter 14).
Nitrogen Cycling
Authors: Fisk Melany C. , Brooks Paul D.
Published: November 2020

In this chapter, we discuss the current understanding of internal N cycling, or the flow of N through plant and soil components, in the Niwot Ridge alpine ecosystem. We consider the internal N cycle largely as the opposing processes of uptake and incorporation of N into organic form and mineralization of N from organic to inorganic form. We will outline the major organic pools in which N is stored and discuss the transfers of N into and from those pools. With a synthesis of information regarding the various N pools and relative turnover of N through them, we hope to provide greater understanding of the relative function of different components of the alpine N cycle. Because of the short growing season, cold temperatures, and water regimes tending either toward very dry or very wet extremes, the alpine tundra is not a favorable ecosystem for either production or decomposition. Water availability, temperature, and nutrient availability (N in particular) all can limit alpine plant growth (chapter 9). Cold soils also inhibit decomposition so that N remains bound in organic matter and is unavailable for plant uptake (chapter 11). Consequently, N cycling in the alpine often is presumed to be slow and conservative (Rehder 1976a, 1976b; Holzmann and Haselwandter 1988). Nonetheless, studies reveal large spatial variation in primary production and N cycling in alpine tundra across gradients of snowpack accumulation, growing season water availability, and plant species composition (May and Webber, 1982, Walker et al., 1994, Bowman, 1994, Fisk et al. 1998; chapter 9). Furthermore, evidence for relatively large N transformations under seasonal snowcover (Brooks et al., 1995a, 1998) and maintenance of high microbial biomass in frozen soils (Lipson et al. 1999a) provide a complex temporal component of N cycling on Niwot Ridge. Our discussion of N cycling on Niwot Ridge will focus on two main points: first, the spatial variation in N turnover in relation to snowpack regimes and plant community distributions; and second, the temporal variability of N transformations during both snow-free and snow-covered time periods.
The Collapse of Thermal Contraction
Authors: Oreskes Naomi
Published: November 2020

In 1901, Karl Zittel, president of the Bavarian Royal Academy of Sciences, declared that “Suess has secured almost general recognition for the contraction theory” of mountain-building. This was wishful thinking. Suess’s Das Antlitz der Erde was indeed an influential work, but by the time Suess finished the final volume (1904), the thermal contraction theory was under serious attack. Problems were evident from three different but equally important quarters. The most obvious problem for contraction theory arose from field studies of mountains themselves. As early as the 1840s, it had been recognized that the Swiss Alps contained large slabs of rock that appeared to have been transported laterally over enormous distances. These slabs consisted of nearly flat-lying rocks that might be construed as undisplaced, except that they lay on top of younger rocks. In the late nineteenth century, several prominent geologists, most notably Albert Heim (1849 –1937), undertook extensive field work in the Alps to attempt to resolve their structure. Heim’s detailed field work, beautiful maps, and elegant prose convinced geological colleagues that the Alpine strata had been displaced horizontally over enormous distances. In some cases, the rocks had been accordioned so tightly that layers that previously extended horizontally for hundreds of kilometers were now reduced to distances of a few kilometers. But in even more startling cases, the rocks were scarcely folded at all, as if huge slabs of rocks had been simply lifted up from one area of the crust and laid down in another. Heim interpreted the slabs of displaced rock in his own Glarus district as a huge double fold with missing lower limbs, but in 1884 the French geologist Marcel Bertrand (1847–1907) argued that these displacements were not folds but faults. Large segments of the Alps were the result of huge faults that had thrust strata from south to north, over and on top of younger rocks. August Rothpletz (1853–1918), an Austrian geologist, realized that the Alpine thrust faults were similar to those that had been earlier described by the Rogers brothers in the Appalachians. By the late 1880s, thrust faults had been mapped in detail in North America, Scotland, and Scandinavia.
From Fact to Theory
Authors: Oreskes Naomi
Published: November 2020

If continental drift was not rejected for lack of a mechanism, why was it rejected? Some say the time was not ripe. Historical evidence suggests the reverse. The retreat of the thermal contraction theory in the face of radioactive heat generation, the conflict between isostasy and land bridges, and the controversy that Wegener’s theory provoked all show that the time was ripe for a new theory. In 1921, Reginald Daly complained to Walter Lambert about the “bankruptcy in decent theories of mountain-building.” Chester Longwell opined in 1926 that the “displacement hypothesis, in its general form . . . promises a solution of certain troublesome enigmas.” A year later, William Bowie suggested in a letter to Charles Schuchert that it was time for “a long talk on some of the major problems of the earth’s structure and the processes which have caused surface change. The time is ripe for an attack on these larger phases of geology.” One possibility is that the fault lay with Wegener himself, that his deficiencies as a scientist discredited his theory. Wegener was in fact abundantly criticized for his lack of objectivity. In a review of The Origin of Continents, British geologist Philip Lake accused him of being “quite devoid of critical faculty.” No doubt Wegener sometimes expressed himself incautiously. But emphatic language characterized both sides of the drift debate, as well as later discussions of plate tectonics. The strength of the arguments was more an effect than a cause of what was at stake. Some have blamed Wegener’s training, disciplinary affiliations, or nationality for the rejection of his theory, but these arguments lack credibility. Wegener’s contributions to meteorology and geophysics were widely recognized; his death in 1930 prompted a full-page obituary in Nature, which recounted his pioneering contributions to meteorology and mourned his passing as “a great loss to geophysical science.” Being a disciplinary outsider can be an advantage — it probably was for Arthur Holmes when he first embarked on the radiometric time scale. To be sure, there were nation alistic tensions in international science in the early 1920s— German earth scientists complained bitterly over their exclusion from international geodetic and geophysical commissions— but by the late 1920s the theory of continental drift was associated as much with Joly and Holmes as it was with Wegener.
Abundance and Measurement of Stable Isotopes
Authors: Criss Robert E.
Published: November 2020

The discovery of isotopes is best understood in the context of the spectacular advances in physics and chemistry that transpired during the last 200 years. Around the year 1800, compounds and elements had been distinguished. About 39 elements were recognized, and discoveries of new elements were occurring rapidly. At about this time, the chemist John Dalton revived the ancient idea of the atom, a word derived from the Greek “atomos,” which literally means “indivisible.” According to Dalton’s theory, all matter is made of atoms which are immutable and which cannot be further subdivided. Moreover, Dalton argued that all atoms of a given element are identical in all respects, including mass, but that atoms of different elements have different masses. Even today, Dalton’s atomic theory would be accepted by a casual reader, yet later developments have shown that it is erroneous in almost every one of its key aspects. Nevertheless, Dalton’s concept of the atom was a great advance, and, with it, he not only produced the first table of atomic weights, but also generated the concept that compounds comprise elements combined in definite proportions. His theory laid the groundwork for many other important advances in early nineteenth-century chemistry, including Avogadro’s 1811 hypothesis that equal volumes of gas contain equal numbers of particles, and Prout’s 1815 hypothesis that the atomic weights of the elements are integral multiples of the weight of hydrogen. By 1870, approximately 65 elements had been identified. In that year, Mendeleev codified much of the available chemical knowledge in his “periodic table,” which basically portrayed the relationships between the chemical properties of the elements and their atomic weights. The regularities that Mendeleev found directly lead to the discovery of several “new” elements—for example, Sc, Ga, Ge, and Hf—that filled vacancies in his table and confirmed his predictions of their chemical properties and atomic weights. Similarly, shortly after Rayleigh and Ramsay isolated Ar from air in 1894, the element He was isolated from uranium minerals in 1895; the elements Ne, Kr, and Xe were found in air in 1898; and Rn was discovered in 1900.
Chihuahuan Desert Fauna: Effects on Ecosystem Properties and Processes
Authors: Whitford Walter G. , Bestelmeyer Brandon T.
Published: November 2020

This chapter focuses on the direct and indirect effects of animals on ecosystem processes and/or their effects on ecosystem properties. This set of effects has been the primary focus of animal studies on the Jornada Experimental Range (JER) and the Chihuahuan Desert Rangeland Research Center (CDRRC) during the twentieth century. Early studies dealt with animal species that were thought to reduce the amount of primary production that was available to support livestock. With the establishment of the International Biological Programme (IBP) in the late 1960s and its premise that ecosystems could be modeled based on energy flow, animal studies were designed to measure energy flow through consumer populations. Those studies yielded estimates of consumption of live plant biomass between 1% and 10% of the annual net primary production (NPP) (Turner and Chew 1981). From these studies Chew (1974) concluded that in most ecosystems consumers process only a small fraction of the NPP as live plant material but play important roles in ecosystems as regulators of ecosystem processes rather than energy flow. Chew’s hypothesis was then the focus of animal studies in the Jornada Basin for nearly 30 years. Studies of animals as regulators of ecosystem processes led to the expansion of Chew’s hypothesis to include the effects of animals on ecosystem properties, such as patchiness. Many of the studies examined in this chapter support the hypothesis that animals affect spatiotemporal heterogeneity and in turn are affected by it. Because this research focused on the role of animals in ecosystems, studies of animal populations were conducted simultaneously with functional studies. Population and behavioral studies were considered an integral part of the central theme because they supported an understanding of the spatial and temporal variation of desert ecosystem properties. We review animal studies that focused on spatial patterns in the distribution and ecosystem effects of several taxa and guilds. Large-scale ecosystem degradation and vegetation changes in the Jornada Basin occurred prior to studies of animal populations (Buffington and Herbel 1965). Therefore, it is important to bear in mind that the published data on animal populations reflect vegetation and ecosystem conditions that are very different from the conditions in which many Chihuahuan Desert species existed only a century before (see chapter 10).
Legal Aspects of the Continental Shelf
Authors: Smith Robert W. , Taft George
Published: November 2020

The 1982 United Nations Convention on the Law of the Sea (the Convention) establishes a comprehensive framework for addressing the issues implicated in the uses of ocean space. It represents both a codification of customary international law and the development of new rules of law. The Convention contains 17 Parts, 320 articles, 9 annexes, and a Final Act. The history of the development of the Convention and its subsequent implementation is outlined in chapter 2. The provisions of the Convention relating to the continental shelf are largely contained in articles 76-85, annex II (regarding the Commission on the Limits of the Continental Shelf), and annex II of the Final Act (which contains a statement of understanding concerning a specific method to be used in establishing the outer edge of the continental margin in very unusual circumstances). The provisions set forth the parameters of a regime in an area in which the coastal State exercises sovereign rights for the purposes of exploring and exploiting the natural resources of the seabed and seafloor. The first article of Part VI, article 76, defines the continental shelf in a manner which is scientifically based, legally defensible, and politically acceptable. The formula to define the outer limit of a coastal State's continental shelf is complex, but workable. At a minimum under the Convention, coastal States have sovereign rights regarding the seabed and subsoil of the continental shelf out to 200 M measured from its baseline, whether or not the physical continental shelf extends to that limit, subject to the delimitation of boundaries with neighboring adjacent or opposite States. Article 77 provides that the sovereign rights, both within and beyond 200 M regarding the continental shelf, are exclusive rights in the sense that if a coastal State does not explore the continental shelf or exploit its natural resources, no one may undertake these activities without the express consent of the coastal State. In addition, those sovereign rights "do not depend on occupation, effective or notional, or any express proclamation." The Convention allows a coastal State to claim an exclusive economic zone which shall not extend beyond 200 M from the baseline from which the territorial sea is measured.
Satellite Positioning Methods
Authors: Ashkenazi Vidal , Hill Chris
Published: November 2020

In the previous chapter, positioning was examined from a historical perspective, recognizing that in many parts of the world, such data are not just useful, they are frequently the only data available. But in many areas, the case for extending the limits of the continental shelf will be dependent on the acquisition of new data, and for the most part, this will mean the use of satellite navigation systems. Therefore, this chapter deals in some detail with current and future satellite navigation and positioning systems. The first generation of satellite navigation systems used the principle of the Doppler shift of transmissions from satellites to provide measurements of a user's position. The Doppler shift of an emitted signal is related to the relative velocity between the source of the signal and the point at which it is received. The apparent frequency of the received signal is increased when the emitter is moving toward the receiver, and decreased when it is moving away. This phenomenon can often be observed in everyday situations, such as when a vehicle drives past a pedestrian. The pitch of the sound from the vehicle appears to drop as it passes the pedestrian, due to the transition from increased to decreased frequency of the sound. In satellite Doppler systems, measurements of the Doppler shift of signals from the satellites are combined with knowledge of the satellite's position and velocity (its ephemeris), to give an indication of the receiver's position. TRANSIT was the first operational satellite navigation system (see chapter 7). Data-processing techniques were developed which allowed a receiver to be located with respect to another at a known location, to an accuracy of the order of 1 m. TRANSIT ceased operation as a position and timing system at the end of 1996. A similar system to TRANSIT was developed by the Soviet Navy in 1965. The system, known as TSIKADA, is still operational today (2000). Since satellite Doppler systems rely on the accumulation of measurements over a period of time to provide a useful measure of a receiver's position, they could not be used as true real-time satellite navigation systems (see chapter 7).
Gravity and Magnetic Methods
Authors: Carruthers Richard M. , Cornwell John D.
Published: November 2020

Lateral variations in the density and magnetization of the rocks within the crust give rise to "anomalies" in the Earth's gravity and magnetic fields. These anomalies can be measured and interpreted in terms of the geology both in a qualitative sense, by mapping out trends and changes in anomaly style, and quantitatively, by creating models of the subsurface which reproduce the observed fields. Such interpretations are generally less definitive in themselves than the results from seismic surveys (see chapter 12), but the data are widely available and can provide information in areas where other methods are ineffective or have not been applied. As the different geophysical techniques respond to specific rock properties such as density, magnetization, and acoustic velocity, the results are complementary, and a fully integrated approach to data collection and interpretation is generally more effective than the sum of its parts assessed on an individual basis. Gravity and magnetic data have been acquired, at least to a reconnaissance scale, over most of the world. In particular, the release into the public domain of satellite altimetry information (combined with improved methods of data processing) means that there is gravity coverage to a similar standard for most of the offshore region to within about 50 km of the coast. Magnetic anomalies recorded from satellites provide global coverage, but the high altitude of the observations means that only large-scale features extending over many 10s of kilometers are delineated. Reconnaissance aeromagnetic surveys with flight lines 10-20 km apart provide a lateral anomaly resolution similar to that of the satellite gravity data. Oceanographic surveys undertaken by a variety of academic and research institutions are another valuable source of data in remote regions offshore which supplement and extend the more detailed coverage obtained over the continental shelves, for example, by oil companies in areas of hydrocarbon interest. Surveys over land vary widely in terms of acquisition parameters and quality, but some form of national compilation is available from many countries. A number of possible applications of the potential field (i.e., gravity and magnetic) data follow from the terms set out by UNCLOS. Paragraph 4(b) of article 76 states, "In the absence of evidence to the contrary, the foot of the continental slope is to be determined as the point of maximum change in the gradient at its base" (italics added).
Initial Assessment
Authors: Macnab Ron
Published: November 2020

The previous chapters have outlined the various techniques for acquiring data on the continental shelf and adjacent areas. We now need to consider how to most effectively draw those various data sets together. This chapter describes a generic procedure for determining whether a coastal State is likely to be entitled to establish a continental shelf limit beyond 200 nautical miles (M), in order to circumscribe an area where it may exercise sovereign rights over natural resources of the seabed and subsoil. In most cases, this procedure will begin with the assembly and analysis of existing information, with the objectives of determining provisionally the outer limit of the continental shelf and of assessing the long-term economic potential of seabed resources beyond 200 M. If the analysis of available information is satisfactory in all respects and justifies such action, the coastal State may proceed directly to the preparation of a claim for submission to the UN Commission on the Limits of the Continental Shelf. If, on the other hand, the result of the investigation is inconclusive or otherwise unsatisfactory on account of inaccurate or incomplete information, the coastal State may opt to acquire new information that enhances existing data holdings, and to repeat some or all of the analyses. The above steps are illustrated in the generic flow diagram of figure 16.1, outlined in table 16.1, and discussed in some detail in the remainder of this chapter. The essence of article 76 is to define a procedure whereby a coastal State with a wide continental margin may claim jurisdiction over certain resources of the seabed beyond the 200-M limit. It follows that the location of the 200-M limit should be known with a reasonable degree of reliability. It is portrayed on the official charts of many nations. However, not all of these charts are constructed at scales or projections that readily lend themselves to the visualization and analysis of information such as sounding profiles and seabed morphology that may need to be examined in conjunction with the 200-M limit. From time to time, therefore, it may be necessary to portray the 200-M limit on a chart that is custom-built, or which covers a more restricted area.
Ridge Issues
Authors: Taft George , Kagami Hideo
Published: November 2020

The Third United Nations Conference on the Law of the Sea sought to establish a definition of the continental shelf that would accommodate the interests of a number, albeit a minority, of coastal States. This included consideration of various submarine elevations, including ridges, and their relationship to the regime of the continental shelf. For a variety of reasons, submarine and oceanic ridges have proved to be contentious. Indeed, this chapter proved to be the most difficult of all the chapters in this book to obtain a text to which all the authors, scientists, and lawyers could agree. Therefore, rather than produce an anodyne chapter which might have summarized only those areas of agreement, we considered it best to also cover areas where agreement was lacking. This provides the reader with both sides of the argument and the opportunity to reach their own view on the basis of the evidence presented. Some of the contentious areas are . . . i. Whether or not article 76 should be interpreted in such a manner as to preclude a country situated on a ridge from having a continental shelf beyond 200 M. ii. Whether bathymetry (reflecting geomorphology) should be given more or less weight than, or the same weight as geology in any consideration of a continental shelf beyond 200 M, including extension along an oceanic ridge, iii. Whether the fact that article 76 refers to the continental shelf being a natural prolongation of the land territory "to the outer edge of the continental margin" means that it can (or cannot) be applied to an island sitting on top of an oceanic ridge, iv. Whether or not article 76 can be interpreted in such a way as to allow a coastal State to "jump" its claim from the margin onto an adjacent ridge. v. Whether or not article 76 limits the use of ridges so that coastal States do not unreasonably extend their continental shelf regime. . . . Ultimately, for the answers to these questions, the reader will need to look to the Commission on the Limits of the Continental Shelf (the Commission), together with the outcome of diplomacy.
Thermodynamic Scaling Near the Critical Point
Authors: Chimowitz Eldred H.
Published: November 2020

Thermodynamic scaling near the critical point is a signature of critical phenomena, and many useful applications of supercritical solvent fluids depend upon exploiting this behavior in some technologically interesting way. Near the critical point, many transport and thermodynamic properties show anomalous behavior which is usually linked to the divergence of certain thermodynamic properties, such as the fluid’s isothermal compressibility. In figures 3.1 and 3.2 we depict the near-critical behavior of both the density of xenon and the thermal conductivity of carbon dioxide, respectively, adapted from published data [1, 2]. The onset of what appear to be critical singularities in these properties is clearly evident in both instances. In this chapter, we focus upon the thermodynamic basis for this type of behavior. In the theory of critical phenomena, the limiting behavior of certain thermodynamic properties near the critical point assumes special significance. In particular, properties that diverge at the critical point are of interest, and this divergence is usually described in terms of scaling laws.
The Renormalization-Group Method
Authors: Chimowitz Eldred H.
Published: November 2020

The renormalization-group (RG) method discussed in this chapter has assumed a pivotal role in the modern theory of critical phenomena. It attempts to relate the partition function of a given system to that of a “similar system” with decreased degrees of freedom through a process referred to as renormalization. Exactly how these degrees of freedom are removed from the system, what we mean by a “similar” system, and how successive systems are coupled to one another are essentially the questions we take up in the introductory treatment given in this chapter. The RG method is a topic with large scope and found widely disseminated in an extensive physics literature on the topic; however, it is seldom found in engineering journals. Our purpose here is to try and make sense of some basic ideas with the RG approach so that it is more accessible to this wider community. For this we often rely upon some prior exposes of the subject in more specialized settings [1, 2, 3, 5]. In its complete sense, the RG method has only been made to work, at least analytically, for a few simple statistical-mechanical models. But aside from these numerical results, many important and quite general insights about critical phenomena can be developed from studying this approach to the problem, especially the central role played by length scale as a factor in describing the phenomenology. These ideas have significantly enhanced our understanding of ideas like scale invariance, universality classes, relevant scaling fields (as opposed to irrelevant ones), Hamiltonian renormalization, and so on; these and related concepts lie at the center of modern discourse on the subject. The essential concepts of the approach can be well illustrated using the Ising system since, with this model, lattice spins are fixed in space, which makes the analytical work quite transparent. This approach, called real space renormalization, is the RG method studied in this chapter.
Transport in the Critical Region
Authors: Chimowitz Eldred H.
Published: November 2020

The behavior of dynamic properties in the critical region is important in many engineering applications, and in this chapter we investigate this topic, focusing upon diffusion. In the literature, the term critical slowing down is used to describe the long relaxation times that occur when criticality is approached. Does this mean that diffusion processes per se come to a halt and, if not, how does slowing down manifest itself in fluids? We see that, in spite of the nonequilibrium nature of this topic, equilibrium concepts still play a key role in describing dynamics in the critical region. To begin this discussion, we investigate the dynamic behavior of a tagged fluid molecule as it experiences random fluctuations in its position in the fluid. These fluctuations would be induced by random thermally induced collisions between the tagged species and other fluid molecules. This type of dynamics is referred to as Brownian motion or a random walk. A schematic showing two 10-step trajectories depicting a random walk in two dimensions is shown in figure 12.1, and its analysis leads naturally to the definition of the self-diffusion coefficient.
Discovering Concepts in Structural Data
Authors: Cook Diane J. , Holder Lawrence B.
Published: November 2020

The large amount of data collected today is quickly overwhelming researchers’ abilities to interpret the data and discover interesting patterns. In response to this problem, a number of researchers have developed techniques for discovering concepts in databases. These techniques work well for data expressed in a nonstructural, attribute-value representation and address issues of data relevance, missing data, noise and uncertainty, and utilization of domain knowledge (Fisher, 1987; Cheeseman and Stutz, 1996). However, recent data acquisition projects are collecting structural data describing the relationships among the data objects. Correspondingly, there exists a need for techniques to analyze and discover concepts in structural databases (Fayyad et al., 1996b). One method for discovering knowledge in structural data is the identification of common substructures. The goal is to find substructures capable of compressing the data and to identify conceptually interesting substructures that enhance the interpretation of the data. Substructure discovery is the process of identifying concepts describing interesting and repetitive substructures within structural data. Once discovered, the substructure concept can be used to simplify the data by replacing instances of the substructure with a pointer to the newly discovered concept. The discovered substructure concepts allow abstraction over detailed structure in the original data and provide new, relevant attributes for interpreting the data. Iteration of the substructure discovery and replacement process constructs a hierarchical description of the structural data in terms of the discovered substructures. This hierarchy provides varying levels of interpretation that can be accessed based on the goals of the data analysis. We describe a system called Subdue that discovers interesting substructures in structural data based on the minimum description length (MDL) principle. The Subdue system discovers substructures that compress the original data and represent structural concepts in the data. By replacing previously discovered substructures, multiple passes of Subdue produce a hierarchical description of the structural regularities in the data. Subdue uses a computationally bounded inexact graph match that identifies similar, but not identical, instances of a substructure and finds an approximate measure of closeness of two substructures when under computational constraints.
Education and Religion in the Nation’s Service, 1868-1888
Authors: Kemeny P. C.
Published: November 2020

“Can the oversight of the religion and morals of the young men, long kept up in American Colleges,” President James McCosh asked an international audience of Presbyterian leaders in 1884, “be maintained any longer?” “Three-fourths to nine-tenths” of America’s colleges, McCosh observed, earnestly “continue to profess religion.” But state institutions, he noted, “scarcely profess to keep up any religion” lest they “offend” any religious minority. Some of the nation’s larger colleges also find it “vain” to give religious instruction to students. Yet the absence of religious education in “our secular institutions,” according to McCosh, was not the only problem facing American higher education. To avoid “the Infidelity” now evident in some parts of American higher education, many denominations were establishing their own institutions. Yet, in McCosh’s estimation, the academic quality of their faculties was so low that these institutions actually injured the cause of religion. “The time is over,” the brusque Scotsman insisted, “when men are to be appointed to our College chairs simply because they are pious or loud in their orthodoxy.” Unless Christian institutions have a faculty “equal in ability and scholarship” to the leading colleges and universities, the nation’s best students “will, in spite the efforts of ministers, flock to the Secular Colleges, which will then control them, and may use the intellectual life which they possess to the worst of purposes.” To McCosh, his colleagues at Princeton, and many peers at other institutions, parents and students should not have to choose between scholarship or orthodoxy. When Charles W. Eliot, president of Harvard College, accepted an invitation to debate the role of religion in collegiate education two years later before the Nineteenth Century Club in New York City, McCosh welcomed the opportunity to present a case for preserving evangelical religion’s place in the halls of the nation’s leading academic institutions. At Princeton, evangelical ideals and practices helped the institution fulfill its dual purpose of meeting the nation’s need for educated leaders and, as the college’s first president termed it, serving as a “Seminary of vital Piety as of good Literature.”