bluuebunny/crossref_metadata_2025 huggingface dataset:
Health, State Medicine, and Henry Ingersoll Bowditch The Radical Approach
Authors: Cumbler John T.
Published: November 2020

On September 15, 1869, Massachusetts governor Andrew appointed seven members to the state board of health. The men appointed to that board had a new vision of medicine and the roles of science and the state in protecting health. For these men, medicine should do more than just cure; it must also prevent illness. Their understanding of illness was expansive, and it led them to a concern about filth and pollution. They also came to believe that for science and medicine to perform their new role in society, they needed the backing and power of the state. On September 22, the board met for the first time, electing George Derby as secretary and Henry Ingersoll Bowditch as chair. Bowditch was a logical choice for chair. In addition to being one of the region’s leading doctors, he came from a respected Boston family, and he held the professorship of clinical medicine at Harvard School of Medicine. He was vice president of the American Medical Association (later he would be president) and the author of several scientificjournal articles. Bowditch served as a medical volunteer to the Union army and lost a son in battle. Moreover, it had been his idea to form a state board of health. In a speech before the Massachusetts Medical Society in 1862, Bowditch argued that medicine should serve the people. To do so required the creation of a state board of health, “one that eventually will be of more service . . . to the inhabitants of this state . . . by [its] united and persistent efforts to increase the state authority.” Bowditch was not the only one to advocate for a state board. Dr. Edward Jarvis, a well known sanitary reformer, had as well, and along with Bowditch, he pushed the idea, only to have it fail in the legislative house in April of 1866 as “inexpedient,” despite Governor Andrew’s endorsement. Three years later, a typhoid epidemic in western Massachusetts encouraged state representatives from the Connecticut River Valley and farther west to back a bill for a state board.
Apollonia
Authors: Fant Clyde E. , Reddish Mitchell G.
Published: November 2020

Apollonia of Macedonia, a city scarcely known even in Greek history, is on the verge of new prominence as a recent discovery brings its past to light. In the summer of 2000 a farmer digging in his fields near Nea (“new”) Apollonia, 30 miles east of Thessalonica, made an amazing discovery. In the bottom of a trench he found a wreath of thirty solid-gold ivy leaves, decorated with two bunches of grapes, that weighed more than a pound. Only three other wreaths of this type and quality have ever been discovered in all of Greece. Archaeologists from Thessaloniki dated the find at approximately 350 B.C.E., or more than 2,350 years old. (This remarkable wreath is currently on display in the Archaeological Museum in Thessaloniki.) The following day their probings uncovered a statue believed to be an image of the goddess known as the Nike of Samothraki, or the Winged Victory of Samothrace. Subsequently, massive fortifying walls and five towers from the 5th century B.C.E. were uncovered. Likewise, two pottery kilns and sixteen cist (stone slab) graves have been unearthed. Archaeologists now believe that this finding marks the location of ancient Apollonia of Macedonia. More surprising, they estimate its population at 10,000, roughly the same as that of Athens during the same period. The city is believed to have existed from approximately 400 B.C.E. to the 8th century C.E. and to have reached its zenith under Philip II of Macedon, the father of Alexander the Great. The first inhabitants of Apollonia were refugees from the nearby Chalkidiki peninsula who fled that location when it was threatened by Athenian warships during the Peloponnesian War. Prior to the recent discoveries, Apollonia was known only as a station on the ancient trade route between the east and west. King Xerxes of Persia passed through the area in 480 B.C.E. (Herodotus 7.112–115), as did Alexander the Great in his epic journey to the east some 150 years later (Arrian, Anabasis 1.11.4).
Antioch on the Orontes
Authors: Fant Clyde E. , Reddish Mitchell G.
Published: November 2020

At one time Antioch on the Orontes was one of the three largest and most important cities of the Greco-Roman world, along with Rome and Alexandria (Egypt). Although Antioch faded from prominence centuries ago, the present city, with its population of approximately 150,000, is still a rewarding place to visit. The museum of the city, the Hatay Archaeological Museum, contains one of the best collections of ancient mosaics of any museum in the world. In ancient times Antioch on the Orontes was a part of Syria and thus is sometimes referred to, especially in biblical studies, as Antioch of Syria. (Fifteen other cities in the ancient world were named Antioch as well.) Today the city, now known as Antakya, is just north of the Syrian border, in the Hatay province of southern Turkey. The Orontes River (today called the Asi) connected the city to the Mediterranean Sea. Seleucus I Nicator, one of the generals of Alexander the Great, founded the city. At first Antigonus, another general, controlled Syria, but he was defeated in 301 by Seleucus and other leaders. Seleucus then gained control of Syria and established his own cities, including Antioch and its port city of Seleucia Pieria. Seleucus named the city, which soon became the capital of the Seleucid kingdom, after his father, Antiochus. Subsequent Seleucid rulers, including Antiochus I Soter (r. 281–261 B.C.E.), Seleucus II Callinicus (r. 246–225 B.C.E.), and Antiochus IV Epiphanes (r. 175– 164 B.C.E.), enlarged and enhanced the city. Tigranes of Armenia captured the city in 83 B.C.E., but in 66 B.C.E. he was defeated by the Roman general Pompey, who made Antioch the capital of the Roman province of Syria. Both Julius Caesar and Augustus visited the city, and both erected various buildings there. (The wedding of Mark Antony to Cleopatra likely took place in Antioch. Ancient sources indicate it occurred in Syria but do not specify the city. As the capital, Antioch was the likely location.) During the Roman period, Antioch was a large, cosmopolitan city, the third largest city in the Roman world after Rome and Alexandria.
Derbe
Authors: Fant Clyde E. , Reddish Mitchell G.
Published: November 2020

One of the cities visited by the Apostle Paul during his travels, Derbe has almost vanished today. A few inscriptions, coins, and literary references and an unexcavated mound bear scant testimony to a city that was one of the early recipients of the preaching of Paul and Barnabas. The ancient city of Derbe was located southeast of Iconium (modern Konya) in the ancient region of south-central Asia Minor known as Lycaonia. Several sites have been proposed for the precise location of Derbe, most of them located near the modern town of Karaman. The location that has the strongest claim to being the authentic site of Derbe is the tumulus (mound) Kerti Höyük, which is situated approximately 15 miles northeast of Karaman (ancient Laranda) and near the village of Aşïran (Ekinözü). On the side of this mound in 1956, Michael Ballance discovered a white limestone block approximately 41 inches high, 27 inches wide, and 27 inches thick. The stone block is inscribed with a dedication by the council and the people of Derbe honoring Emperor Antoninus Pius. In the inscription, which has been dated to 157 B.C.E., the city was likely referred to as Claudioderbe, a special title given to the city during the time of Emperor Claudius. (Part of the face of the stone immediately preceding the word Derbe is broken off. The name Claudioderbe appears on 2nd-century-C.E. coins from Derbe.) Another inscription mentioning Derbe, this one from a tombstone from the 4th–5thcentury C.E., was discovered in the nearby village of Suduraǧi. This inscription, surrounded by five engraved concentric circles, mentions “the most God-loving Michael, bishop of Derbe.” Michael Ballance says he was shown this inscribed marble slab in 1958 and was told by the villagers of Suduraǧi that the inscription was found nearby at Devri Şehri, about 2.5 miles southeast of Kerti Höyük. Bastiaan van Elderen reported seeing the slab in 1962 and said that the people of Suduraǧi were adamant that the inscription came from Kerti Höyük.
Hierapolis
Authors: Fant Clyde E. , Reddish Mitchell G.
Published: November 2020

Hierapolis is a popular tourist site, featured frequently on travel posters and tourist advertisements because of the adjacent spectacular calcified cliffs. Equally as impressive as the white cliffs, however, are the remains of the ancient city and the excellent museum at the site. Along with Colossae and Laodicea, Hierapolis was one of the major cities of the Lycus River valley. While Colossae and Laodicea are on the southern side of the Lycus River, Hierapolis (today known as Pamukkale) is north (or northeast) of the river. The site of the ancient city is approximately 12 miles north of the modern city of Denizli. The most striking aspect of the city, in ancient as well as modern times, is the sight of the calcified white cliffs, formed by mineral deposits from the water flowing over the cliffs. From these white cliffs, which can be seen from the ruins of Laodicea, approximately 6 miles away, Hierapolis derived its modern name of Pamukkale (meaning “cotton castle”). The date of the founding of the city of Hierapolis is uncertain. Because the earliest inscription found at Hierapolis dates from the reign of Eumenes II of Pergamum (r. 197–159 B.C.E.), the founding of the city has usually been dated to the time of the Pergamene kingdom. But because of an inscription in the theater that lists various tribal names, some of which are derived from the names of members of the Seleucid family who ruled parts of Asia Minor during the 4th and 3rd centuries B.C.E. (such as Seleucidos and Antiochidos), the founding of the city should likely be moved back to the time of the Seleucid kings. Even the origin of the name of the city is uncertain. One tradition is that the Pergamene rulers named the city after Hiera, the wife of Telephus (son of Hercules and grandson of Zeus), the mythical founder of Pergamum. Another explanation is that the name means “holy city” (hieros in Greek means “holy”) and that the city was so named because of the temples located there. The latter explanation may have arisen after the mythological connection was forgotten.
Southern Cyprus
Authors: Fant Clyde E. , Reddish Mitchell G.
Published: November 2020

In Southern Cyprus the principal site of interest is Paphos, where the Apostle Paul encountered the Roman governor of Cyprus, Sergius Paulus. But other fine sites of interest range from Paphos to Larnaca, a distance of approximately 80 miles. Since there are airports in both locations and ferries arrive at Limassol, a visit might begin at any one of these places. In any case, with an early start it is possible to make a round trip between Paphos and Larnaca in one day and see the principal sites. A much easier itinerary, however, involves seeing the sites in the Paphos area on one day and the sites in Larnaca on another day, along with those between Paphos and Larnaca. The two sites in the south referred to in the Bible are Paphos and Kition (Kittim), which is mentioned in the Hebrew scriptures. Related sites include St. Paul’s Pillar, the Catacombs of Agia Solomoni, the Tombs of the Kings, Paleopaphos, the Temple of Aphrodite, Kourion, the Temple of Apollo, and the Church of St. Lazarus, as well as several museums. The route below begins at Larnaca and proceeds toward Paphos, since that is the direction Paul and his companions traveled. At one time, Kition was one of the greatest naval powers in the Mediterranean, and its mercenaries even served in the deserts of southern Judea. Today its ruins still suggest the might of this ancient city. The site of ancient Kition, known in the Bible as Kittim, is located in the modern city of Larnaca. In the construction of Larnaca, whose name likely came from the Greek word for sarcophagus (larnax), or coffin, many sarcophagi were unearthed from ancient Kition. Larnaca was the location of a settlement of Mycenaeans as early as the 13th century B.C.E. Later abandoned, the site was rebuilt around 1200 B.C.E. by Achaean refugees following the destruction of the great Mycenaean centers of mainland Greece. A second wave of immigrants arrived about 1150 B.C.E. The original mud-brick city walls were rebuilt in the 12th century B.C.E. with cyclopean stones, huge rectangular ashlar blocks. After an earthquake in 1075 B.C.E., the city was resettled closer to the sea.
Ecology, Engineering, and Management
Authors: van Eeten Michel J. G. , Roe Emery
Published: November 2020

Ecology, Engineering, and the Paradox of Management is the first book that addresses and reconciles what many take to be the core paradox facing environmental decision-makers and stakeholders: How do they restore the environment while at the same time provide ever more services reliably from that environment, including clean air, water and energy for more and more people? The book provides a conceptual framework, empirical case analyses, and organizational proposals to resolve the paradox, be it in the US, Europe, or elsewhere. Thus, Ecology, Engineering, and the Paradox of Management has multiple audiences. First are the key professions involved in the protection and improvement of ecosystems and in the provision and delivery of services from those ecosystems. These include ecologists (and other natural scientists such as conservation biologists, climatologists, forest scientists, and toxicologists), engineers (as well as hydrologists, environmental engineers, civil engineers, and line operators), modeling and gaming experts, managers, planners, and power, agriculture, and recreation communities. Another audience includes university researchers in ecology, conservation biology, engineering, the policy sciences, and resource management. Those interested in interdisciplinary approaches in these fields will also find the book especially helpful. Finally, those interested in the Everglades, the Columbia River Basin, San Francisco Bay-Delta, and the Green Heart of western Netherlands will find new insights here, as the book provides a detailed examination of the paradox in each of these cases.
Adaptive Management in a High Reliability Context: Hard Problems, Partial Responses
Authors: van Eeten Michel J. G. , Roe Emery
Published: November 2020

The examples found at the beginning of this book are, to our minds, neither instances of a lack of societal commitment to saving the environment nor evidence of unreasonable demands for highly reliable services. If they were that, the obvious answer would then be to bite the bullet and take either the environment or the services more seriously. In our view, the examples really express the hard paradox of having to improve the environment while ensuring reliable services at the same time. Beyond specific examples, the strongest expressions of the paradox being taken seriously in terms of the budgets and stakes involved are those large-scale adaptive management initiatives proposed and undertaken in regions where they seem most difficult to implement; that is, where the reliable provision of services is a priority. Just what “reliability” is for the kinds of organizations we study is detailed in chapter 4. Here, we take a closer look at our case studies to see how the issues are articulated empirically. The paradox is even enshrined in law. The mandate of the Pacific Northwest Electric Power Planning and Conservation Act of 1980, for example, is to “protect, mitigate and enhance fish and wildlife affected by the development, operation, and management of [power generation] facilities while assuring the Pacific Northwest an adequate, efficient, economical, and reliable water supply.” But how to do this? Or, as one ecologist, Lance Gunderson (1999b, p. 27), phrased the paradox, “So how does one assess the unpredictable in order to manage the unmanageable?” The answer usually given by ecologists and others is to “undertake adaptive management” (chapter 2). The decision maker learns by experimenting with the system or its elements, systematically and step-by-step, in order to develop greater insight into what is known and not known for managing ecosystem functions and services. Learning more on the ground about the system to be managed is imperative, especially given imprecisely defined terms such as “restore,” “enhance,” and “reliable.” As the senior biologist planner at the Northwest Power Planning Council told us, the last clause of the Power Act “AERPS” (adequate, efficient, economical, and reliable power supply) “never has been quantified, so it is not very clear what it actually means.” He is not alone.
Introduction: A Framework for Biodiversity Studies
Authors: Gosz James R. , Perevolotsky Avi
Published: November 2020

Biodiversity is regarded as a scientific concept, a measurable entity, as well as a social–political construct (Gaston 1996, Wilson 1993). The aim of this volume is to develop the scientific basis for biodiversity studies, and for the integration of the concept into management practice. We emphasize biodiversity as a powerful, integrative concept—one that requires careful articulation and further conceptualization before application. Diversity is a concept that refers to the range of variation or differences among a set of entities; biological diversity then refers to variety within the living world. An example of biological diversity is “species diversity,” which is commonly used to describe the number, variety, and variability of the assemblage of living organisms in a defined area or space. However, biodiversity as a concept has evolved. Current definitions expand the biological diversity concept to emphasize the multiple dimensions and ecological realms in which biodiversity can be observed. These definitions stress that biodiversity encompasses at least four kinds of diversities: genetic diversity, species or taxonomic diversity, ecosystem diversity, and landscape diversity (McAllister 1991; Solbrig 1993, Stuart and Adams 1991; Groombridge 1992; Heywood 1994, Wilson 1993). Two main problems emerge as a consequence of the broad scope that the biodiversity concept has taken at present. Cast as questions, the problems are: (1) How do we incorporate processes (e.g., foraging, energy and nutrient flows, patch dynamics) into a concept that is based on seemingly static entities (i.e., individual organisms, species, habitat types, patch types)? (2) How do we integrate across ecological subdisciplines (e.g., ecosystem, population, landscape ecology) and across scales that are involved in biodiversity studies? The two problems are not mutually exclusive. Indeed, they are inseparable and complementary. For example, to determine how species diversity and ecosystem processes interact requires incorporation of entities and processes, as well as integration of community and ecosystem ecology. The focus on both entities and processes reflects the long-recognized dichotomy of structure and function in biology and ecology. Clearly, both structure and function must be integrated in order to successfully solve ecological questions. Dealing with biodiversity brings this needed integration into focus.
The Effects of Grazing on Plant Biodiversity in Arid Ecosystems
Authors: Ward David
Published: November 2020

Conventional wisdom views heavy grazing as the major cause of desertification in semiarid and arid areas of Africa, Asia, and Australia (see, e.g., Acocks 1953, Jarman and Bosch 1973, Sinclair and Fryxell 1985, Middleton and Thomas 1997). Nowhere is the effect of heavy grazing more apparent than in the Sahel of Africa (Sinclair and Fryxell 1985). This land denudation has resulted in a negative feedback loop via decreased soil nutrient status and increased soil albedo (due to lower vegetation cover), causing increased evaporation and decreased precipitation, which in turn reduces the stocking capacity of the land, further exacerbating the negative effects of grazing (Schlesinger et al. 1990). A less dramatic result of overgrazing is a long-term decline in agricultural productivity. For example, the arid Karoo region of South Africa has experienced no climatic change over the last two centuries, yet there has been a 50% decline in stocking rates in seven of eight magisterial districts from 1911 to 1981 (Dean and McDonald 1994). These authors ascribe this decline to heavy grazing that reduced palatable plant populations and hence the carrying capacity of the vegetation in the long term. These examples of the negative effects of grazing in arid ecosystems lie in stark contrast with a large number of African studies that compared the effects of commercial (privately owned) and communal (subsistence, no private ownership) ranching on vegetation and soils (e.g., Archer et al. 1989, Tapson 1993, Scoones 1995, Ward et al. 1999a,b, reviewed by Behnke and Abel 1996). In spite of 5–10-fold higher stocking rates on communal ranches, few studies have shown differences in effects on biodiversity, plant species composition and soil quality between these ranching types (Archer et al. 1989, Tapson 1993, Scoones 1995, Ward et al. 1999a,b—fig. 14.1). Similarly, studies of grazing in Mediterranean semiarid grasslands (reviewed by Seligman 1996) and Middle Eastern arid rangelands (Ward et al. 1999b) show that the effects of grazing on biodiversity are relatively small. A consensus has developed in recent years that arid grazing ecosystems are nonequilibrial, event-driven systems (see, e.g., O’Connor 1985, Venter et al. 1989, Milchunas et al. 1989, Parsons et al. 1997).
Reconciliation Ecology and the Future of Species Diversity
Authors: Rosenzweig Michael L.
Published: November 2020

Alexander von Humboldt (1807) provided the first hint of one of ecology’s most pervasive rules: larger areas contain more species than do small ones. Many ecologists see that rule—the species–area relationship—as one of ecology’s very few general laws (e.g., Lawton 1999, Rosenzweig and Ziv 1999). In the past two centuries, ecologists have learned a lot about species–area relationships. I will explore that knowledge and show that we can already use it in the struggle to minimize extinction losses. It teaches us what proportion of diversity is truly threatened and how to prevent most losses by applying a new strategy of conservation biology. Olaf Arrhenius (1921) and Frank Preston (1960) formalized the species–area pattern by fitting it with a power equation: . . . S = Caz (1) . . . where S is the number of species, A is the area, and C and z are constants. For convenience, ecologists generally employ the logarithmic form of this equation: . . . log S = c + z log A (2) . . . where c = log C. (Note that I do not use the jargon term “species richness.” To understand why, see Rosenzweig et al. 2003.) The species–area power equation, or SPAR, can be fitted to an immense amount of data (Rosenzweig 1995). Ecologists are not sure why a power equation fits islands or continents. But we do have a successful mathematical theory for areas within a province. Brian McGill (personal communication) has deduced the species–area curve within provinces from four assumptions: • The geographical range of each species is independently located with respect to all others. • Species vary in abundance with respect to each other. • Species have a minimum abundance. • Each species’ abundance varies significantly across its own range, being relatively scarce more often than relatively common. (“Relatively” means with respect to its own average abundance.) Data support all four assumptions. From them, McGill shows that there is a species–area curve and that it approximates a power equation whose z-value ranges between 0.05 and 0.25 with a mean of about 0.15.
The Dirac Equation
Authors: Dyall Kenneth G. , Faegri Knut
Published: November 2020

The purpose of this chapter is to introduce the Dirac equation, which will provide us with a basis for developing the relativistic quantum mechanics of electronic systems. Thus far we have reviewed some basic features of the classical relativistic theory, which is the foundation of relativistic quantum theory. As in the nonrelativistic case, quantum mechanical equations may be obtained from the classical relativistic particle equations by use of the correspondence principle, where we replace classical variables by operators. Of particular interest are the substitutions In terms of the momentum four-vector introduced earlier, this yields In going from a classical relativistic description to relativistic quantum mechanics, we require that the equations obtained are invariant under Lorentz transformations. Other basic requirements, such as gauge invariance, must also apply to the equations of relativistic quantum mechanics. We start this chapter by reexamining the quantization of the nonrelativistic Hamiltonian and draw out some features that will be useful in the quantization of the relativistic Hamiltonian. We then turn to the Dirac equation and sketch its derivation. We discuss some properties of the equation and its solutions, and show how going to the nonrelativistic limit reduces it to a Schrödinger-type equation containing spin.
Relativistic Symmetry
Authors: Dyall Kenneth G. , Faegri Knut
Published: November 2020

Symmetry is one of the great unifying principles of physics and chemistry. Symmetry governs the geometry of molecules, as well as their spectra and the shapes of their crystals. The symmetry of a system provides fingerprints that show up under various probes of the system. Knowledge of the symmetry of a system provides us with valuable information about its properties and behavior, and symmetry may also be used to simplify quantum chemical calculations on the system. All this—provided we have the theory and tools to extract this information. The purpose of this chapter is to provide some of the tools to deal with the symmetries of relativistic quantum chemistry and examine the symmetries of the Dirac equation. Most chemists have a good working knowledge of the finite point group symmetry of molecules. Crystallographers and solid state chemists are also familiar with the symmetries of extended and infinite systems. This is usually accompanied by some knowledge of the mathematical discipline of group theory, which provides a powerful tool for the theoretical treatment of symmetry. Group theory in itself is a vast subject, and only a small fraction of it is actively used in physics, and even less in chemistry. For this presentation our selection will be aimed at those aspects of group theory immediately connected to relativistic quantum chemistry either as a foundation for the theory or in its application and interpretation.We will assume that the reader has a solid background in the finite point group symmetry of nonrelativistic quantum chemistry, as well as a familiarity with group theory at the level of a good advanced undergraduate course (e.g., Atkins and Friedman 1997). For completeness and ease of reference, some of the basic features of group theory commonly encountered by chemists are reviewed in appendix C. Group theoretical concepts beyond this level will be introduced in the text as they are needed. In this chapter, we start with a qualitative introduction of double groups and relativistic molecular symmetries, connecting to the more or less phenomenological introduction this subject is frequently accorded in quantum chemistry. The aim is to provide the necessary insight for those who only need an operational familiarity with double groups.
Basis-Set Expansions of Relativistic Electronic Wave Functions
Authors: Dyall Kenneth G. , Faegri Knut
Published: November 2020

There have been several successful applications of the Dirac–Hartree–Fock (DHF) equations to the calculation of numerical electronic wave functions for diatomic molecules (Laaksonen and Grant 1984a, 1984b, Sundholm 1988, 1994, Kullie et al. 1999). However, the use of numerical techniques in relativistic molecular calculations encounters the same difficulties as in the nonrelativistic case, and to proceed to general applications beyond simple diatomic and linear molecules it is necessary to resort to an analytic approximation using a basis set expansion of the wave function. The techniques for such calculations may to a large extent be based on the methods developed for nonrelativistic calculations, but it turns out that the transfer of these methods to the relativistic case requires special considerations. These considerations, as well as the development of the finite basis versions of both the Dirac and DHF equations, form the subject of the present chapter. In particular, in the early days of relativistic quantum chemistry, attempts to solve the DHF equations in a basis set expansion sometimes led to unexpected results. One of the problems was that some calculations did not tend to the correct nonrelativistic limit. Subsequent investigations revealed that this was caused by inconsistencies in the choice of basis set for the small-component space, and some basic principles of basisset selection for relativistic calculations were established. The variational stability of the DHF equations in a finite basis has also been a subject of debate. As we show in this chapter, it is possible to establish lower variational bounds, thus ensuring that the iterative solution of the DHF equations does not collapse. There are two basically different strategies that may be followed when developing a finite basis formulation for relativistic molecular calculations. One possibility is to expand the large and small components of the 4-spinor in a basis of 2-spinors. The alternative is to expand each of the scalar components of the 4-spinor in a scalar basis. Both approaches have their advantages and disadvantages, though the latter approach is obviously the easier one for adapting nonrelativistic methods, which work in real scalar arithmetic.
Correlation Methods
Authors: Dyall Kenneth G. , Faegri Knut
Published: November 2020

It is well known from nonrelativistic quantum chemistry that mean-field methods, such as the Hartree–Fock (HF) model, provide mainly qualitative insights into the electronic structure and bonding of molecules. To obtain reliable results of “chemical accuracy” usually requires models that go beyond the mean field and account for electron correlation. There is no reason to expect that the mean-field approach should perform significantly better in this respect for the relativistic case, and so we are led to develop schemes for introducing correlation into our models for relativistic quantum chemistry. There is no fundamental change in the concept of correlation between relativistic and nonrelativistic quantum chemistry: in both cases, correlation describes the difference between a mean-field description, which forms the reference state for the correlation method, and the exact description. We can also define dynamical and nondynamical correlation in both cases. There is in fact no formal difference between a nonrelativistic spin–orbital-based formalism and a relativistic spinor-based formalism. Thus we should be able to transfer most of the schemes for post-Hartree–Fock calculations to a relativistic post-Dirac–Hartree–Fock model. Several such schemes have been implemented and applied in a range of calculations. The main technical differences to consider are those arising from having to deal with integrals that are complex, and the need to replace algorithms that exploit the nonrelativistic spin symmetry by schemes that use time-reversal and double-group symmetry. In addition to these technical differences, however, there are differences of content between relativistic and nonrelativistic methods. The division between dynamical and nondynamical correlation is complicated by the presence of the spin–orbit interaction, which creates near-degeneracies that are not present in the nonrelativistic theory. The existence of the negative-energy states of relativistic theory raise the question of whether they should be included in the correlation treatment. The first two sections of this chapter are devoted to a discussion of these issues. The main challenges in the rest of this chapter are to handle the presence of complex integrals and to exploit time-reversal symmetry.
Matrix Approximations
Authors: Dyall Kenneth G. , Faegri Knut
Published: November 2020

In quantum chemistry, regardless of which operators we choose for the Hamiltonian, we almost invariably implement our chosen method in a finite basis set. The Douglas– Kroll and Barysz–Sadlej–Snijders methods in the end required a matrix representation of the momentum-dependent operators in the implementation, and the regular methods usually end up with a basis set, even if the potentials are tabulated on a grid. Why not start with a matrix representation of the Dirac equation and perform transformations on the Dirac matrix rather than doing operator transformations, for which the matrix elements are difficult to evaluate analytically? It is almost always much easier to do manipulations with matrices of operators than with the operators themselves. Provided proper account is taken in the basis sets of the correct relationships between the range and the domain of the operators (Dyall et al. 1984), matrix manipulations can be performed with little or no approximation beyond the matrix representation itself. In this chapter, we explore the use of matrix approximations.
Population Cycles Causes and Analysis
Authors: Berryman Alan A.
Published: November 2020

Ever since Elton’s classic book Voles, Mice and Lemmings (Elton 1942), understanding and explaining the causes of regular multiannual cycles in animal populations has been a central issue in ecology. Many hypotheses have been erected and incessantly argued about, but no clear picture has emerged. Below I briefly sketch the major hypotheses without any attempt to be complete or to comment on their relative merits or demerits. Detailed reviews and discussion can be found in Keith (1963), Krebs and Myers (1974), Finerty (1980), Myers (1988), Royama (1992), and Stenseth (1999). (H1) Physical effects (e.g., Elton 1924, Bodenheimer 1938). Perhaps the most obvious hypothesis is that cycles in animal populations reflect the response of birth and death rates to an external physical factor that is itself cyclic. Two of the more specific physical hypotheses involve periodic climatic factors and sunspot activity. (H2) Predator effects. Lotka (1924) and Volterra (1926) demonstrated that cyclic dynamics are inherent in simple predator-prey models, leading to the hypothesis that regular cycles can result from interactions between predator and prey populations. (H3) Pathogen effects. Anderson and May (1980) showed that, under certain conditions, simple models of infectious disease transmission can generate cycles in host and pathogen populations. This is similar to H2 with the pathogen as a predator. (H4) Plant effects. Several hypotheses have been proposed for the possible role of plants in generating population cycles of herbivores. One is a generalization of H2 in which the plant is considered the prey and the herbivore the predator (Elton 1924, Pitelka 1957). Another involves nutrient cycling: In this hypothesis, nutrient deficiencies are assumed to reduce the resistance of plants, resulting in larger herbivore populations, but nutrients released in feces and decaying animal and plant matter cycle back to the plants, increasing their vigor and resistance, and resulting in reduced herbivory (e.g., White 1974). Another hypothesis argues that herbivore feeding induces sustained chemical and/or physical changes in the plant (delayed induced resistance), which then reduce the reproduction and/or survival of future herbivore generations (Benz 1974, Haukioja and Hakala 1975).
Population Cycles of the Autumnal Moth in Fennoscandia
Authors: Tanhuanpää Miia , Ruohomäki Kai
Published: November 2020

Most species of insect herbivores are restricted to low densities, but some display large-scale density fluctuations, including periodic outbreaks (Faeth 1987, Mason 1987, Hanski 1990, Hunter 1995). The tendency to reach high densities has been related to certain life history traits (Hunter 1991, 1995, Tammaru and Haukioja 1996). However, all populations of a given outbreaking species do not necessarily display high densities. In those cases, outbreaks are frequently more pronounced in populations in physically severe and marginal habitats (Wallner 1987, Myers and Rothman 1995). The autumnal moth, Epirrita autumnata (Borkhausen) (Lepidoptera: Geometridae) is an example of a species with both outbreaking and nonoutbreaking populations. In mountain birch [Betula pubescens ssp. czerepanovii (Orlova) Hämet-Ahti] forests of northern and mountainous Fennoscandia (hereafter northern populations), E. autumnata displays fluctuations with a statistically significant periodicity of 9-10 years (Tenow 1972, Haukioja et al. 1988, Bylund 1995). During outbreaks, forests may be totally defoliated and trees may even die over large areas (Tenow 1972, Lehtonen and Heikkinen 1995). In more southern parts of the species' Holarctic distribution (hereafter southern populations), outbreaks are absent and populations remain at low densities. Cycles of northern E. autumnata populations vary in their amplitude (Tenow 1972). Outbreak densities that produce conspicuous defoliation are typically reached in only some areas, and often in different areas during successive peaks (Tenow and Bylund 1989). Empirical data indicate a fairly regular pattern of fluctuations, that is synchronous on a regional scale, also in populations with moderate or low peak densities (Bylund 1997). Thus, there are two main questions regarding population regulation of northern and mountainous E. autumnata—what causes the cycles, and what causes spatial variations in outbreak severity? In southern populations, the main question is what prevents outbreaks? Larvae of E. autumnata hatch early in spring at the time of birch bud break. Birches (Betula spp.) are the main host plants, although larvae are able to feed on many deciduous trees and shrubs (Seppänen 1970).
Objecives of Tissue Engineering
Authors: Saltzman W. Mark
Published: November 2020

Tissue exchange is an ancient art, but tissue engineering is a new concept. The new thinking about tissue engineering is supported by technologies that were developed during the twentieth century, including advanced cell culture, gene transfer, and materials synthesis. Tissue engineering arose from a diverse group of historical precedents that included pharmacology, surgery, and materials science; each historical line of inquiry engaged different motivations and diverse tools. Therefore, as a substitute for a single definition, this chapter observes tissue engineering from several different angles and attempts to illustrate the field by practical example. The field of tissue engineering can be subdivided in various ways; usually it is organized by organ system, as in hepatic tissue engineering or bone tissue engineering, which are concerned with engineering replacements for liver and bone function, respectively. A coarse subdivision can also be made according to the general objective; most tissue engineering strategies involve replacement of a tissue’s metabolic function, structural function, or both. Here, several overlapping views of tissue engineering are presented: tissue engineering as a logical extension of contemporary medical and surgical therapies; tissue engineering as a method for controlling the normal healing response of tissues; tissue engineering as an effort to repopulate the cellular component of tissues without replacement of the whole organ; tissue engineering as a variety of controlled drug delivery; and tissue engineering as a new method for developing models of human physiology. Metabolism is a coordinated ensemble of chemical transformations that are individually regulated by the action of enzymes. Many metabolic disorders are caused by the defective production of a single enzyme. It is sometimes possible to identify, produce, and use enzymes to reconstitute missing elements of metabolism. For example, the enzyme adenosine deaminase (ADA) is involved in the degradation of purine nucleosides; individuals who lack the gene for ADA cannot produce the enzyme in their bodies. As a result, high concentrations of certain purine nucleoside metabolites accumulate within cells; toxicity due to these metabolites is particularly harmful to B and T lymphocytes.
Garbage of the Golden West
Authors: Wilshire Howard G. , Hazlett Richard W. , Nielson Jane E.
Published: November 2020

In May 1970, Look magazine ran an International Paper Company advertisement, “The Story of the Disposable Environment,” which envisioned a time when “the entire environment in which [we] live” would be discarded. “Colorful and sturdy” nursery furniture “will cost so little, you’ll throw it away when [your child] outgrows it,” the ad enthused, adding for the socially conscious, “experimental lowbudget housing developments of this kind are already being tested.” International Paper never addressed where the disposable housing, furniture, and hospital gowns, or the toxic chemicals used for processing raw materials and manufacturing products— or the fossil fuel emissions—would end up. More than 30 years later, we live with the consequences of that vision, which has transmuted the real environment that we depend on into a nightmarish one, dominated by colossal and increasingly hazardous wastes. For nearly all of human history and prehistory, people dropped their wastes where they lived, expecting the discards would largely disappear. When wastes were relatively minor and all natural materials, many of them did disappear through “natural attenuation”—the diluting or neutralizing effects of natural processes. But even after tens of thousands of years, many items in ancient garbage remain recognizable, and poking through prehistoric dumps can reveal significant details about long-gone people and their ways of life. History shows that soils and waters have limited capacities for processing even natural wastes. Garrett Hardin underscored these lessons in his 1968 essay “The Tragedy of the Commons.” From Roman urbs urbii (cities) to nineteenth-century industrial complexes, the refuse dumped in and around larger population centers issued foul odors and helped spread diseases. Public health concerns eventually forced towns and cities to provide sewers, “sanitary” dumps, water treatment, and more recently, sewage treatment. Nowadays, however, our sewers and dumps receive a sizable proportion of synthetic chemicals with unknown properties as well as millions of tons of toxic wastes, hazardous to humans and other living things.
Conclusion: The Needs of Our Posterity
Authors: Wilshire Howard G. , Hazlett Richard W. , Nielson Jane E.
Published: November 2020

In 1957, Admiral Hyman G. Rickover gave a speech of breathtaking prescience, which warned that the United States would face a resource-depleted future unless it controlled energy consumption. Speaking to an audience of American physicians, he advised that the nation needed to turn away from the allure of affluence and take a truly conservative path—that is, the path of conserving resources and carefully planning consumption levels, to keep itself rich in oil and other mineral wealth for many generations. Rickover’s warnings are especially relevant to the message that we authors hope to convey. The western states have contributed much of the nation’s timber and mineral resources, and most of its major public works projects—including damming of the region’s rivers to provide water supplies and power to western farmers and cities. The whole nation has benefited from exploiting these resources, but now the oil and mineral resources are highly depleted, and clean water also is in short supply. Rickover questioned some of the apparent benefits, however—“Much of the wilderness which nurtured what is most dynamic in the American character has now been buried under cities, factories and suburban developments where each picture window looks out on nothing more inspiring than the neighbor’s back yard,” he said. “The nation’s resources—its lumber, mineral ores, and especially its petroleum—have been used for this remaking of a once-agrarian country into a relatively sterile urban–suburban landscape.” We can add only that this transition from natural lands to sterile urban–suburban and agricultural affluence is the force that has degraded our air, water, and soils. These are nature’s gifts, open to everyone, which the lives and well-being of all creatures in the western states, including its people, depend upon. Rickover feared mindless consumption and population growth, observing, “In the 8,000 years from the beginning of history to the year 2000 A.D. world population will have grown from 10 million to 4 billion, with 90% of that growth taking place during the last five percent of that period. . . .
Individual Muscles Attachments, Action, & Structure
Authors: Goldfinger Eliot
Published: November 2020

The muscles of the head consist of the chewing muscles (temporalis, masseter, and digastric) and the facial muscles (zygomaticus, orbicularis oris, etc.). The chewing muscles are thick and volumetric, and they originate and insert on bone. They open and close the lower jaw, with the action taking place at the jaw joint (temporomandibular joint). The facial muscles are thin. They originate either from the skull or from the surface of other muscles, and they generally insert into other facial muscles or into the skin. When they contract, they move the features of the face (eyes, nose, mouth, ears). As they pull the facial features, they often gather the skin into folds and wrinkles that lie perpendicular to the direction of their muscular fibers (perpendicular to the direction of pull). The mouth region receives the most muscles; therefore, it is the most mobile part of the face. Some facial muscles are so thin that they do not create any direct form on the surface (caninus, malaris, orbicularis oculi), whereas other facial muscles or their tendons may create surface form directly (buccinator, levator labii maxillaris, zygomaticus, and depressor labii mandibularis). Facial muscles are generally more visible on the surface in the horse and the ox than in the dog and feline. The facial muscles, as they move the eyes, nose, mouth, and ears, generate whatever facial expressions animals are capable of producing. . . . • Attachment: A short ligament at the inner corner of the eye, whose inner end attaches to the skull. . . . . . . • Action: Eyelid portion: closes eyelids (blinking), primarily by depressing the upper eyelid. Outer portion: tightens and compresses the skin surrounding the eye, protecting the eyeball. . . . . . . • Structure: The orbicularis oculi is a flat, elliptical muscle consisting of two portions. The eyelid portion lies in the upper and lower eyelids, and the outer portion surrounds the eye and lies on the skull. . . .