bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical and Physical Modification of the Rhizosphere
Authors: Tinker Peter B. , Nye Peter
Published: November 2020

The term ‘rhizosphere’ tends to mean different things to different people. In discussing how a root affects the soil, it is well to bear in mind the spread of the zone being exploited for a particular solute: if this is wide, there may be no point in emphasizing effects close to the root; but if it is narrow, predictions based on the behaviour of the bulk soil may be wide of the mark. In a moist loam after 10 days, a simple non-adsorbed solute moves about 1 cm, but a strongly adsorbed one will move about 1 mm. In a dry soil, the spread may be an order of magnitude less. The modifications to the soil in the rhizosphere may be physical, chemical or microbiological. In this chapter, we discuss essentially non-living modifications, and in chapter 8 the modifications that involve living organisms and their effects. Roots tend to follow pores and channels that are not much less, and are often larger, in diameter than their own. If the channels are larger, the roots are not randomly arranged in the void (Kooistra et al. 1992), but tend to be held against a soil surface by surface tension, and to follow the channel geotropically on the down-side. If the channels are smaller, good contact is assured, but the roots do not grow freely unless some soil is displaced as the root advances. For example, in winter wheat, Low (1972) cites minimum pore sizes of 390–450 μm for primary seminal roots, 320–370 μm for primary laterals, 300–350 μm for secondary laterals, and 8–12 μm for root hairs, though some figures seem large. Whiteley & Dexter (1984) and Dexter (1986a, b, c) have studied the mechanics of root penetration in detail (section 9.3.5). It may compact and reorient the soil at the root surface. Greacen et al. (1968) found that wheat roots penetrating a uniform fine sand increased the density only from 1.4 to 1.5 close to the root; and a pea radicle, a comparatively large root, raised the density of a loam from 1.5 to 1.55.
Multidimensional Water Flow in Variably Saturated Soils
Authors: Warrick Arthur W.
Published: November 2020

Chapters 4 and 5 dealt with one-dimensional rectilinear flow, with and without the effect of gravity. Now the focus is on multidimensional flow. We will refer to two- and three-dimensional flow based on the number of Cartesian coordinates necessary to describe the problem. For this convention, a point source emitting a volume of water per unit time results in a three-dimensional problem even if it can be described with a single spherical coordinate. Similarly, a line source would be two-dimensional even if it could be described with a single radial coordinate. A problem with axial symmetry will be termed a three-dimensional problem even when only a depth and radius are needed to describe the geometry. The pressure at a point source is undefined. But more generally, three-dimensional point sources refer to flow from finite-sized sources into a larger soil domain, such as infiltration from a small surface pond into the soil. Often, the soil domain can be taken as infinite in one or more directions. Also, a point sink can occur with flow to a sump or to a suction sampler. In two dimensions, the same types of example can be given, but we will refer to them as line sources or sinks. Practical interest in point sources includes analyses of surface or subsurface leaks and of trickle (drip) irrigation. The desirability of determining soil properties in situ has provided the impetus for a rigorous analysis of disctension and borehole infiltrometers. Also, environmental monitoring with suction cups or candles, pan lysimeters, and wicking devices all include convergent or divergent flow in multidimensions. There are some conceptual differences between line and point sources and one-dimensional sources. For discussion, consider water supplied at a constant matric potential into drier surroundings. For a one-dimensional source, the corresponding physical problem includes a planar source over an area large enough for “edge” effects to be negligible. For two dimensions, the source might be a long horizontal cylinder or a furrow of finite depth from which water flows. For three dimensions, the source could be a small orifice providing water at a finite rate or a small, shallow pond on the soil surface.
Patients Who Refuse Treatment
Authors: Berg Jessica W. , Appelbaum Paul S. , Lidz Charles W. , Parker Lisa S.
Published: November 2020

From its inception, the law of informed consent has been based on two premises: first, that a patient has the right to receive sufficient information to make an informed choice about the treatment recommended; and second, that the patient may choose to accept or to decline the physician’s recommendation. The legitimacy of this second premise should be underscored because it is too often belied by the everyday language of medical practice. Getting a consent is medical jargon that implies that patient agreement is the only acceptable outcome. Indeed, the term informed consent itself suggests that patients are expected to agree to be treated rather than to decline treatment. Unless patients are viewed as having the right to say no, as well as yes, and even yes with conditions, much of the rationale for informed consent evaporates. Nonetheless, the medical profession’s reaction to patients who refuse treatment often has been less than optimal. The right to refuse treatment is frequently ignored in practice because it is inconsistent with the history and ethos of medicine (1,2). Physicians are trained to treat illness and to prolong life; situations in which they cannot do either—not because of limitations of knowledge or technology, but because patients or third parties reject their recommendations for care—evoke profound feelings of frustration and even anger. It would not be too much to suggest that these confrontations challenge an essential element of the medical identity. Physicians’ reactions to these situations are varied. Some will contend with patients over their refusal, while others, having assimilated a distorted version of patients’ right to refuse treatment, may too quickly abandon their patients to the consequences of their choices, thereby depriving them of the guidance for which patients traditionally have turned to their physicians. Regardless of the quality of care offered to patients or the degree of concern of those who treat them, some patients will have reasons of their own to decline treatment. Before considering how clinicians might respond to these situations, this chapter reviews the status of the law regarding treatment refusal, surveying a legal landscape that has seen dramatic changes in the last decade.
A Landscape Transformed
Authors: Gordon Robert B.
Published: November 2020

This book examines the industrial ecology of 200 years of ironmaking with renewal energy resources in northwestern Connecticut. It focuses on the cultural context of people's decisions about technology and the environment, and the gradual transition they effected in their land from industrial landscape to pastoral countryside.
Introduction
Authors: Enoki Toshiaki , Endo Morinobu , Suzuki Masatsugu
Published: November 2020

There are two important features in the structure and electronic properties of graphite: a two-dimensional (2D) layered structure and an amphoteric feature (Kelly, 1981). The basic unit of graphite, called graphene is an extreme state of condensed aromatic hydrocarbons with an infinite in-plane dimension, in which an infinite number of benzene hexagon rings are condensed to form a rigid planar sheet, as shown in Figure 1.1. In a graphene sheet, π-electrons form a 2D extended electronic structure. The top of the HOMO (highest occupied molecular orbital) level featured by the bonding π-band touches the bottom of the LUMO (lowest unoccupied molecular orbital) level featured by the π*-antibonding band at the Fermi energy EF, the zero-gap semiconductor state being stabilized as shown in Figure 1.2a. The AB stacking of graphene sheets gives graphite, as shown in Figure 1.3, in which the weak inter-sheet interaction modifies the electronic structure into a semimetallic one having a quasi-2D nature, as shown in Figure 1.2b. Graphite thus features a 2D system from both structural and electronic aspects. The amphoteric feature is characterized by the fact that graphite works not only as an oxidizer but also as a reducer in chemical reactions. This characteristic stems from the zero-gap-semiconductor-type or semimetallic electronic structure, in which the ionization potential and the electron affinity have the same value of 4.6 eV (Kelly, 1981). Here, the ionization potential is defined as the energy required when we take one electron from the top of the bonding π-band to the vacuum level, while the electron affinity is defined as the energy produced by taking an electron from the vacuum level to the bottom of the anti-bonding π*-band. The amphoteric character gives graphite (or graphene) a unique property in the charge transfer reaction with a variety of materials: namely, not only an electron donor but also an electron acceptor gives charge transfer complexes with graphite, as shown in the following reactions: . . .xC + D → D+ C+x. . . . . .(1.1). . . . . .xC + A → C+x A−. . . . . .(1.2). . . where C, D, and A are graphite, donor, and acceptor, respectively.
Lattice Dynamics
Authors: Enoki Toshiaki , Endo Morinobu , Suzuki Masatsugu
Published: November 2020

Pristine graphite crystallizes according to the D46h space group. There are twelve modes of vibration associated with the three degrees of freedom of the four atoms in the primitive cell. The hexagonal Brillouin zone and the phonon dispersion curves of pristine graphite, calculated by Maeda et al. (1979), are shown in Figure 4.1. The zone-center (Γ point) modes are labeled as three acoustic modes (A2u + Elu), three infrared active modes (A2u + Elu), four Raman active modes (2E2g), and two silent modes (2Blg). The first calculation of phonon dispersion for the stage-1 compounds KC8 and RbC8 was presented by Horie et al. (1980) on the basis of the model of Maeda et al. (1979) for the lattice dynamics of pristine graphite. Although the calculated phonon energies do not agree well with the experimental data, the model has most of the ingredients for describing the lattice dynamics of stage-1 GICs. A simple review of their work is presented as follows. The primitive cell of KC8, having a p(2 × 2)R0° superlattice, contains 16 carbon atoms and two K atoms. Note that only an αβ stacking sequence is assumed here (see Section 3.6.1). The primitive translation vectors are given by t1 (0, a, 0), t2 = (−√3a/2, a/2, 0), and t3 = (−√3a/4, −a/4, c), where a = 2aG = 4.91 Å and c = 5.35 × 2 = 10.70 Å. The corresponding Brillouin zone is shown in Figure 4.2b. The phonon dispersion for KC8 has been calculated by Horie et al. (1980) on the basis of the Born-von Karman force constant model. This dispersion curve is compared with that of pristine graphite by folding the dispersion curves of graphite into the first Brillouin zone of KC8. Since the side of the Brillouin zone in KC8 is not flat in two directions, as shown in Figure 4.2b, it is a little difficult to transfer the information on the dispersion curves in the first Brillouin zone of graphite into the Brillouin zone of KC8. For simplicity, nevertheless, we assume that the side of the Brillouin zone in KC8 is flat like that of graphite.
Electron Transport Properties
Authors: Enoki Toshiaki , Endo Morinobu , Suzuki Masatsugu
Published: November 2020

In GICs, charge transfer between graphite and intercalate produces a large concentration of charge carriers, featuring an electron or hole nature in donor or acceptor GICs, respectively, as discussed in Chapter 5. GICs are therefore metallic, in contrast with the semi-metallic properties of host graphite. The typical inplane conductivity values for GICs are in the range of ~ 105 Ω−1 cm−1, which is one order of magnitude larger than the in-plane conductivity of pristine graphite (Delhaes, 1977). It is well known that the conductivity of some GICs, such as AsF5, exceeds that of copper, suggesting the properties of synthetic metals (Vogel et al., 1977). As discussed in Chapter 5, GICs have two-dimensional (2D) features in the electronic properties inherent to their stacking structure, so that electron transport is considerably anisotropic between in-plane and interplane electron conduction processes. In the in-plane process, conduction electrons, whose concentration is estimated from eq (5.9), contribute to the coherent electron conduction, and the electrical conductivity σa or resistivity ρa is described as follows (Drude formula): . . .σa =1/ρa = Neμ= Ne2τ/(m*). . . . . .(6.1). . . where N, μ, τ, and m* are the density, mobility, relaxation time, and effective mass of the conduction carriers (electrons or holes), respectively.
Highly Conductive Graphite Fibers
Authors: Enoki Toshiaki , Endo Morinobu , Suzuki Masatsugu
Published: November 2020

From the viewpoint of applications of GICs, a very interesting development is the enhancement in conductivity of the host graphite up to the range of metals, especially for pristine materials with fibrous forms. Much attention has been paid to the exploitation of the order of magnitude intercalation-induced enhancement of the electrical conductivity of graphite fibers for the fabrication of practical high-conductivity, lightweight conductors (Vogel et al., 1977; Goldberg and Kalnim, 1981; Manini et al., 1983, 1985; Murday et al., 1984; Meschi et al., 1986; Natarajan and Woollam, 1983; Natarajan et al., 1983a). The fiber geometry (large aspect length/diameter) ratio offers advantages relative to highly oriented pyrolytic graphite (HOPG) or bulk graphite for the measurement of several of the transport properties of GICs and for increasing the compositional stability of GICs both under ambient conditions and at elevated temperatures (Endo et al., 1981, 1983a). For bulk GICs, intercalation increases the density of carriers by the injection of electrons into the graphite planes in the case of donor guest species, and by injection of holes in the case of acceptor type (see Chapters 5 and 6). The intercalation-induced decrease in carrier mobility that results from the increased scattering by defects and the increased effective mass is outweighed by the larger increase in carrier density, resulting in a large conductivity enhancement as discussed in Section 6.1. The carriers are localized in the graphene planes, and for high-stage compounds (n ≥ 2) the carrier density falls off rapidly with distance from the graphite bounding layer owing to the screening of the charged intercalate layer by the surrounding graphite bounding layers. From an application standpoint, many of the applications of intercalated carbon fibers exploit the high specific conductivity of GICs, which can be expressed as a figure of merit in terms of the conductivity σ divided by the mass density ρm; for a good conductor like copper this is ~ 6 x 10−2 cm /gμΩ. For example, intercalated carbon fibers can provide a lightweight conductor for huge aircraft or motor vehicles, in which, respectively, about 1.5 tonne or 30 kg conventional metallic conductor is used.
Intercalated Fullerenes and Carbon Nanotubes
Authors: Enoki Toshiaki , Endo Morinobu , Suzuki Masatsugu
Published: November 2020

Since the discovery of soccer-ball-shaped C60 (Kroto et al., 1985), fullerenes have been added to the family of allotropes of carbon element. During the fullerene formation by arc-discharge of graphite electrodes, carbon nanotubes were simultaneously grown as a deposit on the electrode (Iijima, 1991). The carbon nanotubes consist of single or multiple graphene sheets rolled in the form of a seamless cylinder, with the diameter of the hollow core being almost 10 Å (similar to that of fullerenes) or even as small as 4 Å. For these new forms of nanometer-sized carbon, so-called nanocarbons, basically similar concepts as GICs have been applied from the aspects of structures, electronic properties, and functionalities that can be controlled by doping or intercalation process. That is, the bonding force between nanoballs or nanotubes is governed by weak van der Waals forces, so that foreign species such as atoms or molecules can be intercalated (or doped) in the van der Waals gaps, similar to graphite. So, from applications and the basic science of these new carbon families, intercalation as well as doping to these hosts has been studied intensively in the last ten years. There are three kinds of doping reactions of guest species into these host materials, which are reflected in their specific structure. Guest atoms can be introduced by substituting the carbon atoms of the hosts. This process is generally called “doping,” as there is a similarity with the doping process in semiconductors, where, in general, there is no long-range periodicity in the guest arrangement against the host crystal. Guests can locate in the hollow cores of fullerenes or carbon nanotubes as well as on their outer surfaces. GICs establish the super-lattice structure between the host of the graphite lattice and the inserted guest species, where the long-range periodicity along the c-axis as well as on the a-b plane is formed. According to the original meaning of “intercalation,” periodic doping to the host materials is defined as intercalation. So, the three kinds of doping are: (1) endohedral doping into the hollow cage; (2) substitutional doping by replacing the carbon atoms on the cages; and (3) exohedral doping where the dopants are sited in the gaps between the cage molecules of a fullerene crystal or between carbon nanotubes in the array of the bundle form.
Reflections
Authors: Haroutounian Joanne
Published: November 2020

The Grand Canyon scene from chapter one seems a distant memory now that we have examined the perspectives of musical talent from experts across different fields. A synthesis of the ideas gleaned from these opening chapters can be embodied once again in that scene and those four friends. The scientific examiner searches beneath the surface for answers. He analyzes the inner core, piece by piece. The psychometricians who systematically refine the measurement of the capacities of music aptitude believe in analyzing the sensory core of musical talent. From this scientific perspective, we learn that the talented musician listens carefully and can discriminate differences in sound. Music aptitude describes the basic capacities that provide this keen discrimination. A musically talented person is fine-tuned in awareness and differentiation of pitch, rhythm, dynamics, and timbre. Our environmental observer searches for answers revealed in surrounding influences and changes over the course of time. She is more concerned with examining how the ongoing flux and flow transforms the whole. The developmental psychologists who examine music intelligence agree that music aptitude is the sensory base of musical talent. However, there is much more to consider and explore. How do these sensory capacities function while engaged in real musical tasks? What tasks can instill metaperceptive functioning as the child develops? From the perspective of the cognitive developmental psychologist, we learn that musical intelligence is a perceptive/cognitive unique way of knowing. The musically talented student develops musical intelligence by solving challenging musical problems that inventively work across the dimensions of performance, composing, improvisation, listening, and critiquing musical work. Our photographer captures the scene through an artistic eye, ever searching for a personal way to interpret this experience to others through his art form. Many hours are spent in the darkroom working through this creative process. With persistence, time, and focus, that personal visual statement will emerge. The performer realizes musical talent through the same artistic process, with the same persistence, focus, and hours of practice.
Final Reflections
Authors: Haroutounian Joanne
Published: November 2020

As we reach the end of our journey in search of the “spark,” initial perspectives may have been stretched or transformed, resulting in a new level of understanding of the term, musical talent. During the course of writing this book, I found myself acutely aware of the musical behavior of friends, students, and performers. What do I see and hear that describes the “spark”? The process of exploring the enigma of musical talent allowed me to reflect on past aesthetic musical experiences, still fresh in my memory. Hopefully, as you paused between chapters of this book, you found your ears focusing on surrounding sounds and your mind reflecting on past musical experiences as well. There are still unanswered questions to ponder and research to pursue, but the basics of musical talent remain constant. The spark of talent is experienced when someone expresses himself or herself through music, making a personal aesthetic statement to others. We have learned that capacities underlying this personal statement can be measured objectively and that the process of developing this interpretation requires metaperceptive reasoning. Students who show potential talent are motivated to learn, eager to hurdle over the next musical challenge. They may have different technical levels, training, and music aptitude scores, but their desire to express themselves through music is readily observable. Can it really be this simple? In looking back at the hundreds of children, teenagers, and adults I have worked with in my studio and classrooms, I visualize a collage of musical capabilities, each unique in its own way. I remember the sensitive, creative seven-year-old who sought out independent ideas from the first lesson, developing into a highly individual composer and musician as an adult. There was the young boy who arrived at the audition/interview with the Moonlight Sonata under his tiny fingers, self-taught, with nuances closely matching the recording he had used as a “teacher.” He reached his goal of playing the Emperor Concerto as a teenager, still craving more Beethoven.
Molecular-Backscatter Lidar Profiling of the Volume-Scattering Coefficient in Cirrus
Authors: Ansmann Albert
Published: November 2020

Backscatter and polarization lidars have already been used extensively to investigate ice clouds (see chapters 2 and 10). A severe limitation is that trustworthy values of the volume-scattering coefficient, one of the most important parameters in the description of the impact of cirrus on climate, cannot be derived from data taken with these lidars. Even the retrieved cirrus backscatter-coefficient profile is often questionable. A discussion of achievements and limitations of the lidar method can be found in the literature (e.g., Fernald et al. 1972; Klett 1981; Fernald 1984; Klett 1985; Sasano et al. 1985; Bissonnette 1986; Ansmann et al. 1992b; Kovalev 1995). The procedure, with all its subsequent modifications and improvements, suffers from the fact that two physical quantities, the particle backscatter coefficient and the particle extinction coefficient, must be determined from only one lidar signal. The uncertainties in the estimated optical parameters are especially large in cirrus, in which the relationship between particle extinction and backscattering can vary strongly in space and time. The situation improved significantly when the first molecular (Raman)-backscatter lidar experiments demonstrated that accurate extinction profiling throughout the entire troposphere is possible (Ansmann et al. 1990, 1992b). After the Pinatubo eruption, it was shown that even at stratospheric heights profiles of the volume-scattering coefficient can easily be obtained with a Raman lidar (Ansmann et al. 1991, 1993a, 1997; Ferrare et al. 1992; Gross et al. 1995; Donavan und Carswell 1997). Two types of molecular-backscatter lidars for extinction measurements are available. The Raman lidar measures lidar return signals elastically backscattered by air molecules and particles and inelastically (Raman) backscattered by nitrogen and/or oxygen molecules (Cooney et al. 1969; Melfi 1972; Ansmann et al. 1992a; Whiteman et al. 1992; Reichardt et al. 1996). Interference-filter polychromators and double-grating monochromators (Arshinov et al. 1983; Wandinger et al. 1998) are used to separate the aerosol signal from the vibrational-rotational or pure rotational Raman signals, to reduce the sky background radiation, and, for the Raman channels, to block the strong elastic-backscatter radiation at the laser wavelength. The suppression has to be better than 10-8. The second type of a molecular-backscatter lidar is the High Spectral Resolution Lidar (HSRL).
Contrail Cirrus
Authors: Schumann Ulrich
Published: November 2020

A contrail (a term introduced for “condensation trail” in 1942 by British pilots) is a visible cloud forming behind aircraft, mainly due to water vapor emissions from the engines. Contrails were first observed behind propeller-driven aircraft in 1915 but form as well from the exhaust of jet engines in cold ambient air (Schumann 1996a). Contrails are visible indicators of cruising aircraft and may impact the Earth's climate. Aircraft exhaust may influence cloud formation either directly by forming contrails or indirectly by causing an aerosol of black carbon soot, volatile particles, and metallic particles which later impact the formation and properties of cirrus clouds in the same air mass at other places. Though the cover by contrails is small compared to the cover by natural cirrus clouds, the potential climatic importance of contrails is being studied intensively. A review of the results obtained so far has been prepared for an assessment on Aviation and the Global Atmosphere (IPCC 1999). It reveals considerable progress in understanding aviation-produced aerosols and cloudiness (Fahey and Schumann 1999). Contrail studies also aid in learning about cirrus formation because contrails are cirrus clouds that form under relatively well defined and reproducible conditions. This chapter reviews some of the progress in understanding contrail formation, occurrence, properties, and radiative impact and identifies some important unanswered questions. Contrail formation can be accurately predicted for given atmospheric temperature and humidity conditions. Contrails form thermodynamically according to the Schmidt-Appleman criterion (Schmidt 1941; Appleman 1953) when the relative humidity (RH) in the plume of exhaust gases mixing with ambient air temporarily reaches or exceeds liquid saturation, so that liquid droplets form on cloud-condensation nuclei (CCN) and soon freeze to ice particles. Measurements have shown that liquid saturation is indeed necessary (see fig. 11.1) and that contrails do not form when the RH exceeds ice saturation (Jensen et al. 1998b; Kärcher et al. 1998a; Schumann et al. 2000). The maximum RH reaches liquid saturation when the ambient temperature is below a threshold temperature of typically -50° to -35°C, depending on ambient pressure and humidity and aircraft properties. This maximum is reached in the young plume (age <0.5 s) closely behind the aircraft.
Dynamic Processes in Cirrus Clouds: A Review of Observational Results
Authors: Quante Markus , Starr David O’C.
Published: November 2020

Local dynamical processes are a key factor determining the microphysical characteristics and typically heterogeneous macroscopic structure of cirrus cloud fields. The internal and background flow fields are correspondingly heterogeneous, albeit only weakly turbulent in most instances, as is discussed here. Nucleation processes and ice crystal growth and habit are intrinsically governed by the local temperature and humidity (saturation ratio) conditions that, in turn, are strongly regulated by the intensity and duration of local updrafts and downdrafts. The microphysical result of equivalent lift by a 50cm/s updraft over a cell width of 200m is quite different from that by a 0.5 cm/s updraft over a 2-km width, even though the overall mass fluxes are equivalent. The great degree of horizontal structure seen in fallstreaks emanating from cirrus likely reflects corresponding variability in microphysical properties, primarily ice crystal size, resulting from variability in the dynamical conditions in the ice-crystal-generating layer. The ice fallout process is a first-order effect in determining overall cloud ice water path. Entrainment of noncloudy environmental air and internal mixing processes are other dynamical aspects that likely play a significant role in cloud life cycle. Dynamical processes provide an important coupling between cirrus cloud microphysical and radiative processes, as described in chapter 18 and illustrated in figure 17.1. Cirrus cloud microphysical properties and macroscopic structure strongly affect the overall radiative properties of a cirrus cloud field and thus the important radiative effect of cirrus in the climate system. Knowledge of the dynamical processes influencing cloud macrophysical properties and microphysical structure is important to understanding the origin of these characteristics. Moreover, cloud-resolving models of cirrus cloud systems must be evaluated in these respects due to the importance of cloud dynamical processes in determining overall cloud properties. Dynamical processes in cirrus are linked to the state of the background flow field that, in general, is characterized by significant wind shear and a stable thermal stratification. Gravity waves are ubiquitous and occur over a range of scales. Upper tropospheric turbulence tends to occur intermittently in patches, likely a result of sporadic shear generation (Kelvin-Helmholtz instabilities) or breaking gravity waves. Turbulent mixing in stratified shear flows is a notoriously difficult subject, and advances in its description have been obtained only recently (e.g., Fernando 1991; Schumann and Gerz 1995; Vanneste and Haynes 2000).
Introduction
Authors: Rockman Deborah A.
Published: November 2020

This is the formal statement of my teaching philosophy, first developed when I initially sought a position in postsecondary art education. Although it has been finetuned and slightly revised over the years, it remains an accurate reflection of what I strive for in the teaching of art, and more specifically in the teaching of drawing. The memory of walking into a classroom of students for which I had complete responsibility for the first time still fills me with wonder and terror. I was no longer the student waiting to be showered with pearls of wisdom from my instructor. I was the instructor. The sense of awe and responsibility that I felt was simply overwhelming, especially since I had come from an undergraduate experience that seemed to promote the laissez-faire approach—for the most part, there was not a lot of active teaching taking place. The unspoken philosophy during my undergraduate years seemed to be one of passive instruction, supported simply by the primarily silent and stoic presence of the faculty member in the classroom. With few exceptions, there were no lectures or demonstrations given, there were no slides shown as examples, there were no textbooks or reference materials recommended or required, no group critiques or discussions of materials and media, no mention of current philosophies or issues in the art world. As students, we were often left to fend for ourselves. For the student with some natural ability, it may not have been a traumatic experience, but for the student who needed more guidance and encouragement, it was often an experience filled with frustration and a sense of failure. This was not the environment I wanted to re-create for the students for whom I was responsible. Once again, although in a very different role, I found myself on my own. As I gathered teaching experience in the classroom, I saw with increasing clarity the significance of the foundation experience for the student of visual arts. The quality of this introductory experience had the power to broadly influence a student’s entire attitude toward his or her education in the arts.
Teaching Essential Drawing Principles in Relation to the Human Figure
Authors: Rockman Deborah A.
Published: November 2020

There is perhaps no more significant experience in the study of drawing than the study of the human figure. One needs only to look to the ancient Greeks and to the Renaissance masters to recognize the historical importance of the human form in the study of the visual arts and the refinement of visual expression. Although the figure’s presence and significance during the period known as modernism and in contemporary art has ebbed and flowed, its influence is always felt to some degree, and no classical or traditional art education would be complete without a substantial focus on drawing and studying the human form. Much debate is currently taking place about the changing role and responsibility of foundation courses for students studying both the fine and applied arts. If we examine those aspects that the fine and applied arts have in common, we find that a concern for communication is paramount, whether it takes place in a gallery or museum, in a television or magazine ad, on a showroom floor, on a computer monitor, or in any number of other locales. The power of the human form to communicate cannot be overstated, primarily because it is what we are. We have things in common with other humans that we have in common with nothing else. Looking at a human form in any context has the potential to provide us with the experience of looking in the mirror, of seeing our own reflection, so to speak. It follows that any significant experience in visual communication must thoroughly examine the role of the figure, and for the visual artist this requires experience with drawing the figure. The fine and applied arts also have in common a concern for principles of design and aesthetics. If we acknowledge the presence of these principles in nature, then we may also recognize an element of universality. Quite simply, I can think of no finer example of the application of principles of design and aesthetics than the living, breathing human form, and the human form is universal.
Evolutionary Significance of Variation
Authors: Mazer Susan J. , Damuth John
Published: November 2020

In this chapter, we consider the causes and evolutionary consequences of phenotypic variation among individuals in random-mating, unstructured populations. We focus on quantitative traits because they illustrate well the difficulties in determining genetic versus environmental causes of phenotypic variation. This is an important step when aiming to make precise predictions concerning phenotypic change in traits that influence individual longevity and reproduction. We also describe several recent conceptual advances concerning the evolutionary significance of population structure. Variation among individuals in quantitative traits is typically measured as total phenotypic variance (the variance estimated from all phenotypes measured in a population). This parameter has three convenient properties; first, total phenotypic variance can be partitioned into components that are themselves variances attributable to different causes, and second, these components are additive, summing to the total phenotypic variance. These attributes allow one to identify and to compare the magnitudes of different sources of variance to determine their relative evolutionary and ecological importance. Third, even when total phenotypic variance in a trait is high, resulting in a high degree of overlap among the means of different Variation among individuals in quantitative traits is typically measured as total phenotypic variance (the variance estimated from all phenotypes measured in a population). This parameter has three convenient properties; first, total phenotypic variance can be partitioned into components that are themselves variances attributable to different causes, and second, these components are additive, summing to the total phenotypic variance. These attributes allow one to identify and to compare the magnitudes of different sources of variance to determine their relative evolutionary and ecological importance. Third, even when total phenotypic variance in a trait is high, resulting in a high degree of overlap among the means of different populations or genotypes, the statistical control of one or more variance components often permits the detection of significant differences among phenotypic means. The proportion of total phenotypic variance accounted for by genotypic versus environmentally induced causes determines the degree of resemblance between parents and offspring or between other types of relatives (e.g., clonal replicates, siblings, half-siblings, maternal lineages). Given that a high degree of resemblance among relatives is a criterion for natural selection to cause evolutionary change, a major goal of evolutionary ecologists is to measure these variance components in wild populations.
Natural Selection
Authors: Fairbairn Daphne J. , Reeve Jeff P.
Published: November 2020

The theory that organisms become adapted to their environment through the process of natural selection has become so ingrained in modern biological thought, and more generally in Western culture of the late 20th century, that it is surely one of the great scientific paradigms of the present era. Evolution and adaptation were both well-accepted concepts by the mid-19th century, at least among French and British natural philosophers. The theory of natural selection, developed by Wallace (1858) and Darwin (1859), provided a functional connection between the two processes. However, despite its logical consistency, natural selection was not accepted as a necessary or sufficient explanation for adaptation until the “evolutionary synthesis” of the mid-20th century, when knowledge from population and quantitative genetics, natural history (e.g., biogeography, ecology, behavior), systematics, and paleontology merged to form the unified theory of adaptive evolution known as neo-Darwinism (see Futuyma 1998 for a concise review of this history). Since that time, natural selection has been accepted as the universal mechanism leading to adaptation, and the two terms have become so closely associated as to be almost tautological. Adaptationist hypotheses are now fundamental to much of modern biology and are becoming increasingly apparent in more disparate fields, such as anthropology, medicine, biochemistry, and psychology (Futuyma 1999). Nevertheless, there is much that natural selection cannot explain. For example, chance events may strongly influence macroevolutionary trends (i.e., the origin and extinction of species and higher taxa), some aspects of molecular evolution, and evolution within small or subdivided populations (Mazer and Damuth, this volume, chapter 2; Nunny, this volume). For this reason, adaptationist hypotheses should be viewed with skepticism until adequately tested (Reznick and Travis, this volume). In this chapter, we carefully define natural selection and discuss methods of measuring selection in natural populations as a means of testing adaptationist hypotheses. These methods are most appropriate for testing hypotheses concerning the adaptive significance of contemporary trait distributions within and among populations (“microevolutionary” hypotheses) and thus have particular relevance for evolutionary ecologists. Readers will find many additional examples of these and other methods of testing microevolutionary adaptationist hypotheses throughout this volume, such tests being an essential component of most research programs in evolutionary ecology.
Senescence
Authors: Tatar Marc
Published: November 2020

At all taxonomic levels, there exists tremendous variation in life expectancy. A field mouse Peromyscus may live 1.2 years, while the African elephant may persist for 60 years, and even a mousesized bat such as Corynorhinus rafinesquei lives a healthy 20 years (Promislow 1991). Part of this variance is caused by differences in ecological risks, rodents being perhaps the most susceptible to predation, and to vagaries of climate and resources. Another portion is caused by differences in senescence, the intrinsic degeneration of function that produces progressive decrement in age-specific survival and fecundity. Senescence occurs in natural populations, where it affects life expectancy and reproduction as can be seen, for instance, from the progressive change in age-specific mortality and maternity of lion and baboon in East Africa. The occurrence of senescence and of the widespread variation in longevity presents a paradox: How does the age-dependent deterioration of fitness components evolve under natural selection? The conceptual and empirical resolutions to this problem will be explored in this chapter. We shall see that the force of natural selection does not weigh equally on all ages and that there is therefore an increased chance for genes with late-age-deleterious effects to be expressed. Life histories are expected to be optimized to regulate intrinsic deterioration, and in this way, longevity evolves despite the maladaptive nature of senescence. From this framework, we will then consider how the model is tested, both through studies of laboratory evolution and of natural variation, and through the physiological and molecular dissection of constraints underlying trade-offs between reproduction and longevity. As humans are well aware from personal experience, performance and physical condition progressively deteriorate with adult age. And in us, as well as in many other species, mortality rates progressively increase with cohort age. Medawar (1955), followed by Williams (1957), stated the underlying assumption connecting these events: Senescent decline in function causes a progressive increase in mortality rate. Although mortality may increase episodically across some age classes, such as with increases in reproductive effort, we assume that the continuous increase of mortality across the range of adult ages represents our best estimate of senescence.
Foraging Behavior
Authors: Kramer Donald L.
Published: November 2020

Foraging is the set of processes by which organisms acquire energy and nutrients, whether the food is directly consumed (feeding), stored for later consumption (hoarding), or given to other individuals (provisioning). Foraging behavior plays an important role in evolutionary biology, not only because it is a major determinant of the survival, growth, and reproductive success of foragers but also because of its impact on predator avoidance, pollination, and dispersal adaptations of potential food organisms. From a contemporary perspective, it is surprising how generally the fundamental role of behavior was neglected in early-20th-century studies of evolution and ecology. Following the development of quantitative techniques and field-oriented approaches by European ethologists, however, interest in foraging, along with other aspects of behavior grew rapidly. Most of this research has sought to describe, explain, and predict foraging behavior quantitatively. The development of an a priori predictive approach using optimality theory, in particular, has revealed a richness and complexity in the patterns of foraging that could not have been imagined only a few decades ago. My goal in this chapter is to provide a brief overview of the main issues in foraging behavior and the logical basis of current approaches. I wish to highlight the successes and potential value of these approaches, while recognizing the gaps and challenges for future research. Contemporary studies of foraging by evolutionary ecologists are based on the synthesis of two research traditions, both emerging during the 1960s. The ethological approach to behavior is illustrated by the research of K. von Frisch and his associates on honeybee foraging and N. Tinbergen and his group on searching behavior of birds. The ethologists’ recognition of behavior as an evolved phenotype, their emphasis on its ecological context, and their careful quantitative and experimental fieldwork set the stage for behavioral ecology (Curio 1976). They classified the behavioral components of foraging, an important contribution to much of the ecological work that followed, and identified a number of widespread characteristics such as localized search following the discovery of a prey (“area-restricted search”) and enhanced detection following experience of a particular prey type (“search image”). The theoretical approach to population ecology was foreshadowed by the Russian V. S. Ivlev.
Predator-Prey Interactions
Authors: Abrams Peter A.
Published: November 2020

Predation has been given many different definitions. For the purposes of this chapter, it is an interaction in which one free-living individual kills and derives resources from another organism. This definition includes finches that consume seeds but does not include fish that eat the siphons of clams that are unable to retract them quickly enough (assuming the clam usually survives the loss of tissue). Both broader and narrower definitions of predation are possible, and a variety can be found in ecology textbooks. Because broad definitions include herbivory and parasitism as forms of predation, the definition used here was chosen to minimize overlap with other chapters in this section. Predation probably arose early in the history of life, and since then, it has been a major source of natural selection on both parties in the interaction. Given the lethal consequences of predation, it is clear that predators will usually have some effect on the rate of increase of their prey. If prey differ in their susceptibility to predators due to heritable differences in characteristics, evolutionary change in antipredator traits will ensue. Because predators must consume prey to survive and reproduce, the selective importance of predation-related traits is obvious. Predators have undergone considerable change and diversification since the first predatory protocell evolved from what was probably a scavenging ancestor. Darwin regarded some of the clearest cases of natural selection as due to the interactions between predator and prey, and that viewpoint is also held by many current-day evolutionary biologists (e.g., Dawkins and Krebs 1979; Vermeij 1994). Predation can be regarded as the most basic interaction between populations. Herbivory and parasitism share the basic property of predation, that one organism consumes some or all of another living organism. Many cases of competition involve predation on the same set of prey species by two or more different predator species. Even when competitors consume nonliving foods, many aspects of the consumption process are similar to consumption of prey by predators. Even mutualism frequently involves one organism eating parts or products of another.