bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidases and Oxygenases
Authors: Frey Perry A. , Hegeman Adrian D.
Published: November 2020

An oxidase catalyzes the oxidation of a substrate by O2 without incorporating an oxygen atom into the product. A monooxygenase catalyzes oxidation by O2 with incorporation of one oxygen atom into the product, and oxidation by a dioxygenase proceeds with incorporation of both atoms of O2 into the product. These reactions generally require an organic or metallic coenzyme, with few exceptions, notably urate oxidase. Mechanisms of action of phenylalanine hydroxylase, galactose oxidase, and ascorbate oxidase are provided in chapter 4 in connection with the introduction of metallic coenzymes. In this chapter, we present cases of well-studied coenzyme and metal-dependent oxidases and oxygenases, and we consider one example of an oxidase that does not require a cofactor. Biochemical diversity may be a characteristic of oxidases, which include flavoproteins, heme proteins, copper proteins, and quinoproteins. The actions of copper and topaquinone-dependent amine oxidases are presented in chapter 3, and in chapter 4, two copper-dependent oxidases are discussed. In this chapter, we discuss flavin-dependent oxidases, a mononuclear iron oxidase, and a cofactor-independent oxidase. Flavin-dependent oxidases catalyze the reaction of O2 with an alcohol or amine to produce the corresponding carbonyl compound and H2O2. Examples include glucose oxidase, which produces gluconolactone and H2O2 from glucose and O2 according to. A D-Amino acid oxidase (EC 1.4.3.3) catalyzes a formally similar reaction to produce an α-keto acid from the corresponding α-D-amino acid. The oxidation of an amino acid by an oxidase produces ammonium ion in addition to hydrogen peroxide and the ketoacid, and so it is formally more complex. It proceeds in the three phases described in, the reduction of FAD to FADH2 by the amino acid, hydrolysis of the resultant α-iminoacid to the corresponding α-ketoacid and NH4, and oxidation of FADH2 by O2 to form H2O2. D-Amino acid oxidase is a thoroughly studied example of a flavoprotein oxidase. The enzyme is a 84-kDa homodimer containing one molecule of FAD per subunit. The mechanisms of the hydrolysis of imines and of the oxidation of dihydroflavins are discussed in chapters 1 and 3.
Discovering Life in America: Tools and Techniques of Biodiversity Inventory
Authors: Stein Bruce A. , Davis Frank W.
Published: November 2020

When John and William Bartram set off for Florida from their Philadelphia farm on a July day in 1765, a vast and largely unknown continent lay before them. Journeying in search of novel and unusual plants for their English patrons, the virgin territories of the southeastern United States provided fertile grounds for their biological explorations. These pioneering naturalists, father and son, lived at a time when new scientific discoveries literally lay around each corner. On this trip alone, they were able to collect or draw more than 200 species new to science. One species that slipped away from them was a “very curious” shrub they found growing along the banks of the Altamaha River in Georgia. Sporting beautiful white flowers accented by a central tuft of orange stamens, the shrubs unfortunately yielded no ripe seeds. Only on a return trip to Georgia some eight years later was son William able to collect seed and bring the species into cultivation—and to the attention of the scientific world. Given the name Franklinia alatamaha, in honor of Bartram’s close friend and fellow Quaker Benjamin Franklin, the shrub turned out to represent a completely new branch of the camellia family. Thanks to its beautiful flowers and foliage, Franklinia quickly became a popular ornamental, and even today it is widely cultivated in gardens. But Bartram’s horticultural introduction of this unique plant was fortuitous for another reason: The species has disappeared from its native habitat along the Altamaha River and was last seen in the wild in 1803. Sadly, Franklinia represents one of the first species known to vanish from the American landscape. While the American frontier formally closed in 1892, the biological discovery of America continues to this day. Not all discoveries are as spectacular as the “curious shrubs” the Bartrams had the good fortune to find, but each, in its own way, is just as important. The ongoing process of exploring our biological frontiers gradually fills in the fabric of our knowledge about the United States and its ecosystems. The knowledge generated by this basic inventory also serves as the backbone of our efforts to protect our nation’s biological diversity.
The Geography of Imperilment: Targeting Conservation toward Critical Biodiversity Areas
Authors: Chaplin Stephen J. , Watson Hal M.
Published: November 2020

The Lake Wales Ridge stretches out along Florida’s central spine, pointing southward like an arrow toward Lake Okeechobee and the Everglades beyond. The “river of grass,” as the Everglades are known, attracts visitors from around the world to experience this unique ecosystem and view its immense wildlife concentrations. Compared to its famous neighbor to the south, the Lake Wales Ridge is virtually unknown to the public. From a biological perspective, though, these low, scrub-covered sand hills are of perhaps greater interest than the immense wetlands of the Everglades, because the ancient sand dunes that form this ridge are home to some of the most distinctive and highly localized species in the world. Yet most of the scrub vegetation that supports these species has been destroyed, replaced by agriculture and housing developments: Only about 15% of this unique habitat remains (Menges 1997). Among the rarest of the ridge’s inhabitants is the Lake Placid scrub mint (Dicerandra frutescens), known from just a handful of localities. This mint produces chemicals that have a powerful deterrent effect on insects and that could provide the key to developing new forms of insect repellents useful to people (Eisner et al. 1990). Although these chemicals protect the mint from being devoured by insects, the plant has little protection against the development pressures that threaten it. Another resident of the ridge is the yellow scrub balm (Dicerandra christmanii), a closely related mint that has an even more restricted distribution. Both of these plants are regarded as critically imperiled (GI), and both are listed by the federal government as endangered. Sharing the Lake Wales Ridge with these rare plants is the Florida scrub jay (Aphelocoma coerulescens), a bird that is mostly restricted to the scrub along Florida’s central ridge but occurs in scattered locations along Florida’s Gulf and Atlantic Coasts as well. Florida scrub jays have the unusual characteristic of living in family groups. To survive in a particular location, these birds need a large enough area of suitable habitat to support a number of these family groupings. This species is regarded as vulnerable (G3) and listed as threatened under the Endangered Species Act.
Masturbatory Insanity and Delinquency
Authors: Goldberg Ann
Published: November 2020

As argued in chapter 4, masturbatory insanity was closely linked to male identity and contemporary notions of masculinity. An additional factor contributing to the obsessive focus of medical practitioners on masturbation was the usefulness of the concept of masturbatory illness to the professional interests and aspirations of medicine and of alienists in particular, a group who embraced the notion of masturbatory illness with special fervor. According to Gilbert, the masturbation diagnosis partly derived from a gap between the “prestige and skill level” of the medical profession. This disjuncture drove doctors “to explain diseases of which they had inadequate knowledge in terms of the moral feelings of their patients.” The issue for psychiatry, this chapter argues, was not so much a gap between prestige and knowledge as the use of a new type of knowledge to enhance the prestige of mental medicine. For it is surely not coincidental that the frenzy over masturbatory insanity coincided with the period in which a nascent psychiatry was struggling to establish itself as a legitimate medical specialty. The notion of masturbatory illness was also, as Foucault has pointed out, connected with the power relationships of nineteenth-century institutions, such as the school, the army, and the insane asylum. The following case study of Johann A., a single, thirty-five-year-old farm laborer and former soldier, shows the role played by the institutions of the army and the insane asylum in masturbatory insanity. It also suggests how masturbation could play a crucial role in the expansion and legitimation of psychiatric expertise through the insertion of a discourse of sexual pathology into areas of behavior long viewed and treated as disciplinary or criminal matters. It did this by providing the scientific basis for the diagnosis of illness in ambiguous cases, where distinctions between delinquency and illness were unclear. The use of the masturbation diagnosis for disciplining male delinquency varied, both institutionally and culturally, by social class. The second part of the chapter explores the different ways that male masturbatory insanity was coded in, and experienced by, lower- and middle-class men.
One-Dimensional Infiltration and Vertical Flow
Authors: Warrick Arthur W.
Published: November 2020

This chapter addresses one-dimensional infiltration and vertical flow problems. Traditionally, infiltration has received more attention than other unsaturated flow procedures, both for empirical formulations and for applications of Richards’ equation. Rarely is infiltration the only process of interest, and from an overall point of view it is only one example of soil water dynamics. Here, we will first emphasize systems for which analytical (or quasi-analytical) solutions can be found. These include the Green and Ampt solution (1911), which adds gravity to the simplified analysis discussed in chapter 4. Then a linearized form of Richards’ equation will be examined, followed by the perturbation of the horizontal problem of Philip leading to his famous series solution. Although the closed-form and quasi-analytical solutions are convenient for calculations and discussing the physical principles, generally, the nonlinearity of Richards’ equation precludes such convenient forms. However, numerical approximations can be used. The conventional numerical methods applied in water and solute transport are based on finite differences and finite elements. Because of its greater simplicity, we will emphasize finite differences and build on the methodology from the saturated-flow example in chapter 3. Richards’ equation is a parabolic partial differential equation reducing to an elliptical form for steady-state cases. The analyses and methods parallel developments for techniques developed primarily for the linear diffusion equation. Many texts exist for numerical methods; one to which we refer is by Smith (1985). Ideally, numerical methods give solutions that are as accurate as the input warrants or as necessary for application. In some cases, results may be easier or more accurate than the evaluation of a complex analytical expression. Clearly, infiltration is of limited duration, with drainage and redistribution occurring over much longer time frames. We will visit briefly some steady-state examples, including layered profile and upward flow from a shallow water table. Other examples include modeling plant water uptake from the profile and drainage of initially wet profiles. The rapid increase in computational power and availability of computers make solutions feasible and routine for problems that were very tedious or time consuming only a few years ago. This is particularly true of the one-dimensional numerical solutions.
Successful African American Young Women and Their Families
Authors: Hrabowski Freeman A. , Maton Kenneth I. , Greene Monica , Greif Geoffrey L.
Published: November 2020

When we read or hear about young African American women in our society, we usually find that the emphasis is on problems—from welfare and teenage pregnancy to violence and drugs. Rarely do the media focus on the success of young Black girls in school or of African American women in professional careers. For example, despite the fact that the nation’s teenage pregnancy rates have steadily declined since 1991, and that the majority of the nation’s pregnant teenagers are not Black, it is common nevertheless for the American public immediately to associate the expression, "babies having babies," with young Black girls. This association is largely created and reinforced by images presented in the media of young African American women in trouble, either as unwed mothers or, in more recent years, as gang members. Less well known are the significant accomplishments and value of African American women and the enormous role they can, and do, play in our nation. Consider the prose of Nobel Prize-winning writer Toni Morrison, and the courageous voice of one of America’s most eloquent child-advocates, Marian Wright Edelman. African American women are achieving at the highest of professional levels, from college presidencies to cabinet posts. Consider, for example, the appointments of Dr. Shirley Jackson, a physicist and the first African American female to earn a Ph.D. in any field at the Massachusetts Institute of Technology, as president of Rensselaer Polytechnic Institute, one of America’s major technological universities, or of Dr. Condoleezza Rice as the President’s National Security Advisor. Notwithstanding these positive accomplishments, most Americans— Black and White—still know very little about these high achievers. Increasingly, entertainers—both women and men—send mixed signals to young Black girls about who they should aspire to become as they move toward womanhood. Often, these images, which tend to be unflattering and even at times degrading, focus on a culture that is excessively influenced by glamour, sex, and violence. In Reviving Ophelia, Mary Pipher discusses the powerful influence of the media in shaping girls’ definitions of themselves through teen magazines, advertisements, music, television, and movies.
Raising Successful African American Young Women What We Have Learned
Authors: Hrabowski Freeman A. , Maton Kenneth I. , Greene Monica , Greif Geoffrey L.
Published: November 2020

It is important to remember that the young women in our study are successful not simply in general, but they have excelled in high school and college math and science courses and performed well on standardized tests. Their success is especially significant in the light of recent legal decisions regarding affirmative action. These decisions make it more difficult for minority children to gain admission to some of the nation’s colleges and universities. The critical challenge minority children face is that if their grades and test scores—the traditional measures of success—are not as competitive as those of their White or Asian counterparts, these underrepresented minority groups may not be able to take advantage of all the educational and career opportunities available in our society. Therefore, we must do all we can to strengthen and elevate the academic performance of these students well before they enter college. We know that schools and teachers are critical in the educational process, and understandably they receive a great deal of attention when we look at student-achievement levels. However, we need to focus much more attention on the role of families in this process, particularly in preparing daughters for success in school. Both parents and daughters agreed that parental or family support, in addition to natural ability, was a major reason for the daughters’ success. We have learned that raising African American girls to become high-achieving women in science is a complex and exciting challenge. The past six chapters have focused on what we have learned from slightly more than one hundred families of successful African American college women in science. The book uses and analyzes the voices of the parents and daughters to illuminate the journeys of these families over three generations. What emerges from their diverse perspectives and backgrounds is a rich and colorful tapestry that helps us understand the values, practices, and strategies that have led to the daughters’ success. The daughters in our study come from a variety of familial, geographic, educational, and economic backgrounds.
Structures and Phase Transitions
Authors: Enoki Toshiaki , Endo Morinobu , Suzuki Masatsugu
Published: November 2020

Graphite intercalation compounds (GICs) have unique layered structures where intercalate layers are arranged periodically between graphite layers. This phenomenon is known as staging, and the number of graphite layers between adjacent intercalate layers is known as the stage number n. As the stage number n increases, the separation between adjacent intercalate layers becomes larger. So the interlayer interactions between intercalate layers become weak, leading to a crossover of dimensionality from three-dimensional (3D) to two-dimensional (2D). Because of their intrinsic anisotropy, GICs exhibit a great variety of structural orderings such as staging, in-plane ordering of intercalate layers, and stacking ordering of both graphite and intercalate layers. The stable stage and in-plane ordering of the intercalate layers depend on the relative strength of the intercalate-graphite interaction to the intercalate-intercalate interaction. At low temperatures the intercalate layers form a variety of 2D superlattices resulting from the competing interactions. At elevated temperatures the superlattice undergoes a transition to a 2D liquid. The migration of intercalate atoms is restricted to the 2D gallery between graphite layers. The critical temperature below which the stacking order appears is equal to or lower than the critical temperature below which the in-plane order appears. In this chapter, we review the subject of structures, phase transitions, and kinetics for donor and acceptor GICs. The subject matter of this chapter is organized as follows. Section 3.1 deals with the general structural characteristics of GICs. Sections 3.2 and 3.3 are respectively devoted to descriptions of liquid state and phase transitions of stage-2 alkali metal GICs. Section 3.4 deals with the discommensuration domain model for high-stage alkali metal GICs. Sections 3.5 and 3.6 are devoted to descriptions of liquid-solid transitions in stage-1 K and Rb GIC. In Sections 3.7-3.9, we describe the stage transition, Kirczenow’s model, Hendricks-Teller-type stage disorder, and fractional stage. In Sections 3.10 and 3.11 we describe the phase transitions of acceptor-type GICs (Br2 GIC and SbCl5 GIC). Section 3.12 treats the ordering kinetics in K GIC and SbCl5 GIC.
Introduction
Authors: Bhushan Nalini , Rosenfeld Stuart
Published: November 2020

Chemistry is a substantial science by the measures of industry, economics, and politics. As an academic discipline, it underlies the vibrant growth of molecular biology, materials science, and medical technology. Although not the youngest of sciences, its frontiers continue to expand in remarkable ways. And although it shares boundaries with every other field of science, it has an autonomy, both methodologically and conceptually; this autonomy, however, continues to be unappreciated by most philosophers of science. Why is there no philosophy of chemistry? Although there have been philosophical writings on chemistry, increasingly so during recent years, curiously enough, no coherent discipline analogous to the philosophy of physics, biology, or mathematics has emerged. Indeed, some would argue that there is no subject matter here to begin with because chemistry is in the end reducible to physics and therefore without a distinct methodology or conceptual repertoire of its own worthy of philosophical consideration. One motivation for this anthology is to demonstrate that this view requires serious rethinking, particularly in the context of modern molecular science. In a 1981 review article entitled “On the Philosophy of Chemistry,” J. van Brakel and H. Vermeeren pointed out that although there is a vast amount of literature on the history of chemistry, there is precious little in the philosophy of chemistry. They observe that “even isolated articles in which the philosophy of science is applied to chemistry are extremely rare: in all cases it is clear that the published work is the outcome of a side interest of the author (most of whom are chemists who developed an interest in the philosophy of science)”. An exception to this lack of interest, cited by van Brakel and Vermeeren, is a strand of scholarly activity in Eastern Europe, particularly Russia, East Germany, and Romania, where books and articles on the philosophy of chemistry have been published since the late 1950s.
Analytical Instrumentation and Instrumental Objectivity
Authors: Baird Davis
Published: November 2020

The bulk of this chapter is concerned with analytical chemistry during and for the first decade after World War II. At this time analytical chemistry underwent a radical change, which can most easily be characterized as a shift from wet chemistry to instrumental methods (Baird, 1993). Although this transformation of analytical chemistry may interest readers of this volume for a variety of reasons, I focus here on a shift in the concept and practice of a kind of objectivity. Objectivity is one of those concepts with generally positive connotations, but whose exact characterization proves elusive. A dictionary tells us that, as an adjective, objective applies to that which has “actual existence or reality.” Objective observation is “based on observable phenomena” and “uninfluenced by emotions or personal prejudices” (American Heritage Dictionary, 1993, p. 940). Objectivity, it would seem, either sits next to truth or defines the right route to truth. What emerges here, however, is a more complicated concept—a concept with a history that serves various agendas through suitable shades of meaning and marriages of convenience with other concepts. The development of instrumental methods in analytical chemistry made possible fast, precise, and accurate analyses of a wide variety of important substances. Instrumental methods changed forever the metals industries, medical diagnosis, oil analysis, and forensic analytical chemistry, to mention a few highlights. In a very real sense, these developments in analytical chemistry made contemporary science and technology possible by opening up vast new continents of information about the world, which could be gained relatively easily and applied toward technological and/or scientific ends. I argue here that these developments in analytical chemistry established a paradigm for one kind of concept of objectivity. Ralph Müller, who will play a central role in this discussion, wrote in the January 1947 issue of the Analytical Edition of Industrial and Engineering Chemistry (the journal that subsequently became Analytical Chemistry): . . .The true instrumental method of analysis requires no reduction of data to normal pressure and temperature, no corrections or computations, no reference to correction factors nor interpolation on nomographic charts. . . .
Starting from Basics
Authors: Tammemagi Hans
Published: November 2020

The landfill has been a child of convenience. Historically, waste was simply dumped in depressions, ravines, and other handy locales that were close to the population centers producing the waste. For centuries this was an acceptable method, but two developments caused serious environmental difficulties with this approach. First, the enormous growth in population resulted in much more garbage being generated, at the same time as land was becoming a scarcer and more valuable resource. Second, the technological and consumer revolution led to the creation of many more hazardous products—particularly synthetic organic substances such as pesticides, PCBs, paint removers, and degreasers, which ultimately wound up in landfills. Landfills grew bigger, and their contents were more toxic than ever before. The child of convenience grew up and turned into an environmental ghoul. Instead of convenience, we need to seek methods of waste disposal that do not impair our environment, use up valuable resources, or place limitations on future resources. Changing engrained habits is not an easy task. We need a revolution that sweeps aside the old ways and introduces new concepts and technologies that are in accord with philosophies that value and protect our environment. Although the gravity of the situation is becoming recognized, and some positive steps—such as streetside recycling programs—are being implemented, there is still an enormous amount to be done. Perhaps we need a different outlook on waste disposal. We should seek disposal technologies and methods that protect the environment; furthermore, these methods must be based on fundamental philosophies that the public understands, agrees with, and buys into. When we seek to redesign waste management, it is important to start with the ultimate objectives firmly in mind. We need goals and a set of rudimentary principles to guide us. Many of us have read a science fiction novel in which a lonely spaceship has been sent to explore a distant galaxy, hundreds of light years away in the farthest reaches of the known universe. Even at hyperspeeds, the spaceship must travel for centuries to reach its destination, requiring several generations of crew to pass their lives aboard the ship.
The Quest
Authors: Haroutounian Joanne
Published: November 2020

A point has been reached in this discussion of musical talent and its identification where some concrete questions must be answered. We have examined perspectives of talent across fields and synthesized a simple set of musical talent criteria. Will teachers and musicians agree that these criteria are valid indicators of talent in students they teach on a daily basis? What must be added to define this criteria further? We recognize the need to identify talented students in music; however, we have yet to find an effective procedure to carry out this identification. What is the best way to unveil potential as well as demonstrated talent in a variety of school settings? The research discussed in this chapter sought to answer these pressing questions. This personal quest began with an analysis of data from the National Research Center on the Gifted and Talented (NRC G/T) at the University of Virginia, augmented by data from different specialized schools. This analysis provided a look at the status quo of what criteria and procedures were currently being used in schools across the country. A survey containing criteria and procedures drawn from this analysis was sent to musicians, teachers, researchers, and specialists across the music and gifted fields in over 15 states. My goal was to see which criteria were deemed “absolutely essential” by people who work with talented music students. In addition, what procedures are currently being used and what types of activities will effectively reveal musical talent? The survey also sought opinions about what performance criteria were important to consider on assessment forms. Quantitative results created a list of criteria and procedures that showed their degree of importance according to the mean of the survey rating scales. Numbers on paper provide quantitative results. However, discussions with experts across the music and gifted fields could allow clarification of ideas, substantive qualitative input, and brainstorming of possible procedures for identification that all seem invaluable for answering questions concerning musical talent. Therefore, this research concluded with a set of interviews of experts across the music and gifted fields of education, research, performance, and psychology to gather this vital information.
Kindling the Spark: Early Development
Authors: Haroutounian Joanne
Published: November 2020

Alullaby winds its way through the intimate confines of the nursery, as a restless baby is soothed to sleep. The rhythm and rocking chair synchronize a pulse as a mother sings softly to her child. The baby listens to the gentle flow of the melody, which drifts into a hum that vibrates against the sleeping child’s tiny head. A few short years later, Mom smiles as she looks in to her three-year-old’s room. Her daughter is nestled in the same rocking chair, singing a rather lopsided version of the same lullaby, gently stroking a rag doll wrapped in a frayed old baby blanket. Children listen before they are born. They are aware of their mother’s heartbeat and the different environmental sounds that filter into the cozy womb. They are surrounded by the low-pitched pulsating sounds of their mother’s cardiovascular system at work. Studies show that pregnant singers find their babies much quieter when they are singing. Instrumentalists report the opposite effect, with lots of internal activity when they are performing. Even before birth, a child recognizes the sound of a mother’s voice and responds to music or familiar sounds. Prenatal studies abound that can measure the movements and startle reflexes of these yet-to-be-born listeners. Loud, sudden noises (above 100 db) cause the fetal heart to beat faster and an immediate startle response. One experiment zapped 15 seconds of a Bach organ prelude (at 100 db) through headphones nestled close to a mother’s abdomen. Not surprisingly, the fetal heart rate accelerated within five seconds of this musical stimulation. Once a baby is born, the effects of these prenatal sounds still have an influence on behavior. Studies of newborns by Salk in the 1960s resulted in the popularity of crib devices that play the sound of an adult heartbeat to soothe babies to sleep. Other studies show the same soothing effect for seven-day-old neonates listening to taped sounds of intrauterine background noises. From birth, the mother’s voice is distinguished from other women’s voices and recognized more readily than the father’s voice—again stemming from prenatal listening experiences.
Cirrus: A Modern Perspective
Authors: Sassen Kenneth
Published: November 2020

It is now understood that the cirrus clouds inhabiting the upper troposphere play a significant role in regulating the radiation balance of the earth-atmosphere system and so must be recognized as a crucial component in solving the human-induced climate change puzzle (Liou 1986). Because of their high altitudes, these cold, ice-dominated clouds act as a thermal blanket by trapping the outgoing terrestrial (infrared) radiation, but, at the same time, they can be effective at reflecting the incoming solar radiation back out to space. The balance between these two radiative processes, the greenhouse and albedo effects, respectively, determines the net impact of cirrus on our climate system. Which process dominates appears to be quite sensitive to the cloud microphysical and macrophysical properties (e.g., see Stephans et al. 1990). These properties in turn depend on the weather processes that generate cirrus, a function of geographic location, thereby complicating the global view. Of current concern is comprehending how cirrus clouds will respond, or feedback, to the effects of global warming caused by the buildup of carbon dioxide and other greenhouse gases. Would the changing atmosphere produce alterations in cirrus clouds that reinforce, or act to negate, the theoretically predicted global warming surmised from fundamental physics? One must also ask whether increasing jet aircraft traffic is creating more cirrus cloud cover, and if this traffic and agricultural activities are increasing the transport of dust and smoke particles into the upper troposphere and affecting, in a radiatively important sense, those cirrus formed naturally. Settling these issues could be pivotal to making difficult decisions on the future use of the Earth's resources. Fortunately, a new generation of meteorological instrumentation has become available. The need for these new measurement capabilities has helped to spawn and adapt instrumentation for cirrus research. Sophisticated cloud measurement capabilities using in situ probes on jet aircraft, satellite multispectral imaging, and remote sensing with lidar, short-wavelength radar, and passive radiometers, have all greatly facilitated cirrus cloud research. Major advancements have also been made in the field of numerical cloud modeling. As will be reviewed briefly here and in depth in following chapters, these developments have significantly advanced our knowledge of the characteristic properties of cirrus clouds over the past few decades.
Laboratory Studies of Cirrus Cloud Processes
Authors: DeMott Paul
Published: November 2020

A number of processes that play a role in the formation, evolution of microphysical properties, and radiative characteristics of cirrus clouds are amenable to investigation in a laboratory setting. These laboratory studies provide fundamental data for quantifying and validating theoretical concepts and help guide investigations involving direct and remote measurements of cirrus. Laboratory data also may be used for formulating parameterizations for numerical cloud models, especially where information is incomplete or full descriptions are not possible. This chapter reviews results from laboratory studies of ice formation, ice crystal growth, radiative transfer, and aerosol scavenging and transformation in the cirrus environment. Emphasis is placed on ice formation in cirrus conditions. The related topic of contrail formation is covered separately in this book. The formation mechanisms of lower stratospheric clouds are reviewed elsewhere (e.g., Tolbert 1994; Peter 1996; Carslaw et al. 1997; Koop et al. 1997a). Laboratory studies of cirrus ice formation are at a rapidly developing stage, so it is useful to provide significant background bases for current and needed studies. Key issues are aerosol composition, ice nucleation mechanisms, and the synergy between theory and laboratory measurements. Vali (1996), Baker (1997) and Martin (2000) discuss some of these issues in review papers. Upper tropospheric aerosol particles play an important catalytic role in the formation of cirrus. The nucleation process is important in determining the microphysical properties of cirrus. Numerical modeling studies (e.g., Jensen and Toon 1994; DeMott et al. 1994, 1997; Heymsfield and Sabin 1989) indicate that variation in the factors that drive the nucleation of ice and variations in the physical and chemical characteristics of aerosol particle populations lead to the formation of cirrus with different microphysical characteristics. Knowledge of the physics and chemistry of aerosols in the upper troposphere and lower stratosphere has evolved at a rapid pace. A detailed accounting of this topic is beyond the scope of this chapter. For the purpose of the present discussion, it is sufficient to note that the aerosol from which cirrus nucleate may vary significantly from place to place. Differences in aerosol properties in time and space occur because particles can arrive to the upper troposphere in so many ways and from so many sources.
Cirrus and Weather: A Satellite Perspective
Authors: Wylie Donald P.
Published: November 2020

Cirrus were originally thought of as benign cloud forms that could be used for predicting the onset of foul weather, such as “mare's tails” and “anvil edges,” but not of great concern because they do not produce any damaging winds or hydrometers. Our original view of cirrus was from the ground, so they were mostly ignored until aircraft started flying in them and making cirruslike contrails in the latter part of World War II. Cirrus limited visibility for the aircraft, and contrails made detection of aircraft from the ground easier. This led to the first studies of cirrus by the Air Force (Stone 1957). Had our first views of earth been from space, cirrus would have been an obvious cloud and often an obstruction to viewing everything else on the planet. Cirrus are difficult to see on visual satellite images, which is deceiving because they reflect enough solar radiation to obscure quantitative measurements of the land and water surfaces. Cirrus are more obvious in window channel infrared images, and they block any sensor that tries to look horizontally through them from either aircraft or satellites. The term “invisible cirrus” originated from an attempt to fly a horizontal viewing sensor on an aircraft for detecting approaching objects (missiles). The sensor was obscured because of its long path length through cirrus, while ground observers did not report the cirrus. Pilots were uncertain whether they were in a cloud or not. The frequency of cirrus reported from satellite data often surprises other scientists. Wylie and Menzel (1999) reported finding cirrus in 25-30% of GOES/VAS (Geostationary Operational Environmental Satellite/Visual spin scan radiometer Atmospheric Sounder) data over the continental United States. A similar satellite instrument flying globally, the HIRS (High Resolution Infrared Radiometer Sounder) on the National Oceanic and Atmospheric Administration (NOAA) satellites, reported cirrus 43% of the time (Wylie and Menzel 1994; Wylie and Menzel 1999). The horizontally viewing SAGE (Stratospheric Aerosol and Gas Experiment) is even more sensitive and reports cirrus in 50-70% of its data (Wang et al. 1996). These numbers should not have surprised people because the compilations of ground-based weather observations by Warren et al. (1988) show cirrus frequencies as high as 75% in Indonesia.
On Cirrus Modeling for General Circulation and Climate Models
Authors: Sundqvist Hilding
Published: November 2020

Cirrus clouds are significant regulators of the earth's radiation budget. Cirrus generally have low ice water content, leading to partial transparency to radiation, and a variety of ice crystal types constitutes the cloud. As a consequence, cirrus have complex optical qualities, which are discussed in other chapters of this book. In this chapter, I discuss the appearance and behavior of the cirrus clouds per se and discuss approaches to include those features in numerical models by parameterization. The number of general circulation models (GCMs) containing physically based parameterizations of cloud processes with prognostic equations for water/ice content increased remarkably during the 1990s. Model simulations of the general circulation of the atmosphere have shown a pronounced sensitivity to modeled optical properties of cirrus (e.g., Ramanathan et al. 1983; Senior and Mitchell 1993; Mitchell 1994b; Fowler and Randall 1996a,b; Kristjansson et al. 1998). Most studies with GCMs and climate models have focused on features of radiation and energy budgets and the modulation of these budgets as a consequence of changes in cloudiness quality or other conditions. Much less attention has been paid to the characteristics and realism of the model cloudiness itself (e.g., Liou 1992). Only meager discussions are generally found on these topics from studies in this context. In most cases, zonally averaged and/or bird's-eyeview cloudiness are reported. The reason for this is the sparseness of observational data, which makes it difficult to conduct a detailed verification of the simulated cloud fields. Many papers on model experimentation on this topic do indeed contain statements that uncertainties in cloud behavior constitute a severe weakness of the simulations (Senior and Mitchell 1993; Mitchell 1994). It is also emphasized that substantial improvement in our understanding of the behavior of clouds (not least cirrus) is required for satisfactory confidence in simulations of different climate scenarios. The critical need for high-accuracy measurements of upper-tropospheric water vapor is emphasized for example, in a paper by Stephens et al. (1996) discussing satellite measurements of water vapor. Clouds also have an indirect effect on climatology because their appearance and disappearance (evaporation) modulate the distribution of water vapor in the atmosphere.
Cirrus, Climate, and Global Change
Authors: Stephens Graeme
Published: November 2020

Understanding the climate of Earth and the way climate varies in time requires a quantitative understanding of the way water cycles back and forth between the atmosphere and at the Earth's surface. The exchanges of water between the surface and atmosphere establish the hydrological cycle, and it is the influence of this cycle on the energy budget of Earth that is central not only to understanding present climate but also to the prediction of climate change. Processes relating to the smallest of the reservoirs of water—namely, the atmospheric branch of the hydrological cycle—play an especially critical role in climate change. Water in vapor phase is the critical greenhouse gas (e.g., Chahine 1992) providing much studied feedbacks on climate forcing (Lindzen 1990; Rind et al. 1991; Stephens and Greenwald 1991; Inamdar and Ramanathan 1998; Hall and Manabe 1999). Water in the form of condensed, precipitation-sized particles is an important source of energy fueling circulation systems and is the fundamental supply of fresh water to life on Earth. Liquid water cloud droplets significantly modulate the radiative budget of the planet (e.g., Wielicki et al. 1995). Water that exists as ice particles suspended in the atmosphere is perhaps the smallest of the water reservoirs of the atmosphere, yet these ice crystals when distributed as part of large-scale cirrus clouds exert a disproportionate influence on the energy and water budgets of the planet. This chapter briefly speculates on the important ways cirrus clouds affect the Earth's climate. The topics discussed are central to what is referred to as the cloud-climate problem, which might be schematically represented in terms of the coupled processes represented in figure 20.1. The two most critical scientific questions associated with the cloud-climate problem are also stated in figure 20.1. Answers to these questions require a clearer understanding of how the large-scale circulation of the atmosphere governs cloud formation and evolution, how these clouds heat and moisten the atmosphere, and how this heating and moistening effect in turn feeds back to influence the dynamical and thermodynamical properties of the atmosphere.
Polyphosphazenes
Authors: Mark James E. , Allcock Harry R. , West Robert
Published: November 2020

Polyphosphazenes comprise by far the largest class of inorganic macromolecules. At least 700 different polymers of this type have been synthesized, with a range of physical and chemical properties that rivals that known hitherto only for synthetic organic macromolecules. Most polyphosphazenes have the general molecular structure. The polymer backbone consists of alternating phosphorus and nitrogen atoms, with two side groups, R, being attached to each phosphorus. The side groups may be organic, organometallic, or inorganic units. Each macromolecule typically contains from 100 to 15,000 or more repeating units linked end to end, which means that (depending on the organic side groups) the highest molecular weights are in the range of 2 million to 10 million. The bonding structure in the backbone is formally represented as a series of alternating single and double bonds. However, this formulation is misleading. Structural measurements suggest that all the bonds along the chain are equal or nearly equal in length, but without the extensive conjugation found in organic polyunsaturated materials. This anomaly will be discussed later. In addition to linear polyphosphazenes with one type of side group, other molecular architectures have also been assembled. These include polyphosphazenes in which two or more different side groups, R1 and R2, are arrayed along the chain in random, regular, or block distributions. Other species exist with short phosphazene branches linked to phosphorus atoms in the main chain. Also available are macromolecules in which carbon or sulfur replace some of the phosphorus atoms in the skeleton. Star-geometry structures, using the symbolism defined, are also accessible. A new and growing area is the field of phosphazene-organic and phosphazene-polysiloxane hybrid linear copolymers, and comb copolymers of the types. In addition, polymers are known in which six-membered phosphazene rings are side groups linked to organic polymers, and where phosphazene rings are linked by organic connector groups to form cyclolinear or cyclomatrix materials.
Miscellaneous Inorganic Polymers
Authors: Mark James E. , Allcock Harry R. , West Robert
Published: November 2020

The polymers discussed in this chapter are simply those that do not fit into one of the earlier, more general categories. They are generally polymers that are not yet of great commercial importance, often because they are so new that much more research needs to be done before they can be utilized effectively. It should be mentioned first that a number of minerals, and glass itself, contain silicon and consist of polymeric structures. Glass is a highly irregular material that consists of rings and linear chains of silicate units in complicated three-dimensional arrangements. On the other hand, some minerals consist of single chains or double chains in which negatively charged oxygen atoms are neutralized by positively charged metal cations. It is sometimes possible to make such materials more tractable by breaking open the cross-links and inserting non-ionic, non-polar groups in their place. Nonetheless, these materials generally are not synthesizable, characterizable, and processable in the way that most organic or inorganic-organic polymers are. The most important class of silicon-containing polymers that have not yet been covered are the polysilazanes, shown. These polymers, or precursors to them, are generally prepared by the reaction of organic-substituted chlorosilanes with ammonia or amines as is shown in reaction.
Preceramic Inorganic Polymers
Authors: Mark James E. , Allcock Harry R. , West Robert
Published: November 2020

One of the most important interfaces in materials science is the one between polymers and ceramics. Ceramics can be viewed as highly cross-linked polymer systems, with the three-dimensional network providing strength, rigidity, and resistance to high temperatures. Although not generally recognized as such, a few ceramics exist that are totally organic (i.e., carbon-based). Melamine-formaldehyde resins, phenolformaldehyde materials, and carbon fibers are well-known examples. However, totally inorganic ceramics are more widely known, many of which are based on the elements silicon, aluminum, or boron combined with oxygen, carbon, or nitrogen. Among the inorganic ceramics, two different classes can be recognized—oxide ceramics and non-oxide materials. The oxide ceramics frequently include silicate structures, and these are relatively low melting materials. The non-oxide ceramics, such as silicon carbide, silicon nitride, aluminum nitride, and boron nitride are some of the highest melting substances known. Non-oxide ceramics are often so high melting that they are difficult to shape and fabricate by the melt- or powder-fusion techniques that are common for oxide materials. One major use for inorganic-organic polymers and oligomers is as sacrificial intermediates for pyrolytic conversion to ceramics. The logic is as follows. Linear, branched, or cyclolinear polymers or oligomers can be fabricated easily by solution- or melt-fabrication techniques. If a polymeric material that has been shaped and fabricated in this way is then cross-linked and pyrolyzed in an inert atmosphere to drive off the organic components (typically, the side groups), the resultant residue may be a totally inorganic ceramic in the shape of the original fabricated article. Thus, ceramic fibers, films, coatings, and shaped objects may by accessible without recourse to the ultra-high temperatures needed for melting of the ceramic material itself. Note, however, that although the final shape of the object may be retained during pyrolysis, the size will be diminished due to the loss of volatile material. If the pyrolysis takes place too quickly, this contraction process may cause cracking of the material and loss of strength.