bluuebunny/crossref_metadata_2025 huggingface dataset:
Discourse of Foreign Farmworkers
Authors: Bauder Harald
Published: November 2020

In 1995, the Ontario provincial government, under conservative premier Mike Harris, repealed legislation put in place the year before by the former central-left government of Bob Rae that protected Ontario’s agricultural workers under the province’s labor code. Migrant workers were also affected by this legislation. In late April 2001, Mexican workers staged a two-day strike in a Leamington greenhouse, and in May 2001, approximately 100 Mexican offshore farmworkers protested in Leamington against substandard working and living conditions, including the lack of safety protection against pesticides, overcrowded living spaces, long working hours, no overtime pay, insufficient medical care, unfair government paycheck deductions, and threats of deportation to their home countries. After these events, some of the protesters were dismissed from the offshore program and sent back to Mexico. The media reports on these protests varied widely. Reports were either sympathetic to the workers’ concerns, or they condemned the protests as unjustified nagging by a small minority of angry workers. Several of the newspaper reports that were sympathetic to the protesting workers (e.g., Kitchener-Waterloo [Ontario] Record 2001; St. Catharines [Ontario] Standard 2001) presented the same quote from an anonymous migrant worker who criticizes the unfair treatment of foreign migrant workers by Canadian employers: “What I’ve realized here in Canada is that employers don’t hire us as human beings. They think we’re animals. . . . The first threat that they always make is that if you don’t like it, you can go back to Mexico.” In a report about the same protests, the Windsor (Ontario) Star quoted farmworkers who articulated similar concerns: “‘Growers don’t care whether you’re injured or not, they only care when you’re healthy,’” and “[the grower] said, ‘If you don’t work faster, you’ll be sent back to Mexico’” (Welch 2001). Other articles gave the events a different spin. A fact-finding mission after the protests uncovered that only a few migrant workers filed formal complaints against their employers. The lack of complaints was interpreted as assurance that workers were satisfied with their employment circumstances.
Landscape and Scale
Authors: Bauder Harald
Published: November 2020

That the offshore program has remained in place for decades and public outcry against it has been minimal is partly the achievement of a carefully spun discourse of foreign farm labor, as we saw in the previous chapter. In this chapter, I examine how this discourse makes use of several strategies. First, it situates the foreign migrant workers in the context of the familiar landscape of rural Ontario. Second, it frames the representation of offshore labor in dualisms of belonging and nonbelonging. Third, it associates various dualisms with different geographical scales. These scale-particular representations enable seemingly contradictory narratives to coexist. However, in the context of the wider discourse, geographical scales and associated dualisms interlock in a manner that situates seasonal migrant labor in subordinate economic and marginal social roles. It is still common among scholars to use essentialized ethnic categories to assess rural landscapes and examine social relationships in agricultural production. In view of such scholarly practices, it is particularly important to expose the ideological underpinnings of landscape representation. Geography has offered many approaches, associated with different traditions of scholarship, to the study of landscape. These approaches variously treat landscape as an expression of rural lifestyle, a manifestation of everyday social space, a material reflection of social relations, and an ideology. I assume the fourth perspective on landscape, which George L. Henderson (2003) also describes as “apocryphal” landscape because it reveals, not authentic social relations, but ideological ways of seeing. When Stephen Daniels and Denis Cosgrove (1988: 1) say, “A landscape is a cultural image,” they refer to the ideological representation of people and objects through landscape. According to this approach to landscape, the manner in which people are situated and represented in landscape can reveal ideologies of subordination and exclusion. For example, the portrayal of Gypsies as uncivilized, dirty, and a “polluting presence” in the English countryside reflects “the assumption that the countryside belongs to the privileged” (Sibley 1995: 107). In this context, landscape is the discursive construction of “a stereotyped pure space which cannot accommodate difference” (108).
Composites
Authors: Mark James E. , Schaefer Dale W. , Lin Gui
Published: November 2020

A relatively new area that involves silicon-containing materials is the synthesis of “ultrastructure” materials (i.e., materials in which structure can be controlled at the level of 100 Å). An example is the “sol-gel” hydrolysis of alkoxysilanes (organosilicates) to give silica, SiO2. The reaction is complicated, involving polymerization and branching, but the overall reaction may be written . . . Si(OR4 + 2H2O → SiO2 + 4ROH (9.1) . . . where the Si(OR)4 organometallic species is typically tetraethoxysilane such as tetraethylorthosilicate (TEOS, with R being C2H5). In this application, the precursor compound is hydrolyzed and then condensed to yield branched polymers. Eventually a continuous swollen gel is formed. The gel is dried at moderately low temperatures to remove volatile species, and then it is fired into a porous ceramic object that can then be densified and machined into a final ceramic part. The production of ceramics by this novel route triggered interest in the ceramics community because of advantages over the conventional powder-processing approach to ceramics. Advantages include (i) the higher purity of the starting materials, (ii) the relatively low temperatures required, (iii) the possibility of controlling the ultrastructure to reduce the microscopic flaws that lead to failure, (iv) the ease with which ceramic coatings can be formed, and (v) the ease with which ceramic alloys can be prepared (e.g., by hydrolyzing solutions of both silicates and titanates). The sol-gel approach has been used to form ceramic-like phases in a variety of polymers. Poly(dimethylsiloxane) (PDMS) is the most popular. PDMS is relatively weak and stands to benefit most from reinforcement. PDMS is easily absorbs the precursor materials generally used in the solgel process. Nearly monodisperse silica microparticles can be obtained using siloxane elastomer mixtures. In some cases, the PDMS has been part of a copolymer, with ureas, imides, amideimides, and dianilines. In other approaches, the particle surface is modified, for example, with a polysiloxane. Siloxane/silica nanocomposites have also been used as “culture-stone-protective materials.” Sol-gel hydrolysis and condensation can be carried out within a polymeric matrix to generate particles of the ceramic material, typically with an average diameter of a few hundred angstroms.
Fluorescent Probes
Authors: Shapiro Howard M.
Published: November 2020

In the jargon of cytometry, cellular characteristics, such as size, nucleic acid content, and membrane potential, are usually referred to as parameters, a term that is also used for the physical characteristics, such as absorption, light scattering, and fluorescence intensity, that are measured by cytometric instrumentation. Fluorescence, as a physical parameter, plays a key role in the detection of probes on beads for multiplexed analysis. Cellular parameters can be classed as intrinsic or extrinsic. Intrinsic cellular parameters are those that can be measured without the use of a reagent; measurement of extrinsic parameters requires the use of reagents, which are almost always referred to as probes, thereby occasioning confusion among molecular biologists new to cytometry. Cellular parameters are also characterized as structural or functional; DNA and RNA content and the presence and copy number of an antigen or nucleic acid sequence are structural parameters, whereas internal pH, membrane potential, and enzyme activity are functional parameters. The distinction between structural and functional parameters blurs at the edge, but the concept has been generally useful. Fluorescent probes allow measurement of the widest variety of extrinsic cellular parameters. For an atom or molecule to fluoresce, it must first absorb a photon, raising an electron to a higher energy level that is known as an excited state. Excitation by absorption requires only about a femtosecond. Fluorescence occurs when the electron loses all or some of the absorbed energy by emission of a photon. The fluorescence lifetime, that is, the period between excitation and emission, is typically on the order of a few nanoseconds for fluorescent organic materials but is notably longer (hundreds of microseconds) for some materials (e.g., lanthanide chelates). In almost all cases, some of the excitation energy is lost nonradiatively by transitions between different vibrational energy levels of the electronic excited state; this loss requires that the emitted energy be less than the energy absorbed, meaning that the fluorescence emission will be at a longer wavelength than the excitation. The difference between the principal excitation and emission maxima in the fluorescence spectrum is known as the Stokes shift, honoring George Stokes, who first described fluorescence in the mid-1800s. Typical Stokes shifts are no more than a few tens of nanometers.
Applications of Flow Cytometry to Cell Adhesion Biology: From Aggregates to Drug Discovery
Authors: Larson Richard S. , Chigaev Alexandre
Published: November 2020

Flow cytometry represents a powerful and evolving methodologic approach to cell adhesion biology. In its beginnings, flow cytometry was used solely to measure the expression of receptors on cellular surfaces and to correlate that expression with biologic function in non-flow-cytometry-based assays. From this primitive beginning, applications have proliferated and now include methodologies that measure real-time aggregation, receptor activity, and the downstream biologic consequences of cell adhesion. These biologic applications have led to platforms that are easily employed as drug screening and target validation tools. Functional assays that measure cell aggregation were initially developed to measure cell–cell interactions in the immune system, especially between cytotoxic cells and various cell types targeted as the focus of their cytotoxic activity. The cytotoxic “effector” cells and the “target” cells were stained with spectrally distinct fluorescent dyes, gently sedimented together into a cell pellet, and allowed to interact under static conditions for designated intervals of time. When resuspended and introduced into the flow cytometer, effector cells adherent to target cells were detected as “conjugate” particles emitting the fluorescence spectra of both dyes. Nonadherent effector and target cells were detected as monochromatically fluorescent particles. By using ion concentration–sensitive cytoplasmic fluorescent probes as the effector cell labels, it was also possible to detect physiological changes in intracellular ionized calcium and pH elicited by adhesion to target cells and to correlate these responses with cytotoxic function. Later, methods were developed for continuously measuring (“real-time”) cell adhesive interactions as they progressed over time in a fluid shear environment. A limitation of early adhesion kinetics analyses was that the fluid shear was generated with a magnetic stir bar and was thus neither homogeneous nor amenable to precise quantification. Subsequent refinement of these methods has enabled flow cytometric analysis of cell mixtures subjected to a more uniform and quantifiable fluid shear environment generated in a cone-plate viscometer. Cell mixtures are sampled periodically from the viscometer into a formalin fixative solution for subsequent off-line flow cytometric analysis. These experiments have been able to demonstrate a remarkable potentiation of adhesion efficiency through the combined action of two sets of adhesion molecules and a progression of adhesion molecule use from one class to another over time.
Rheology and Processing of Polymeric Materials: Volume 1: Polymer Rheology
Authors: Han Chang Dae
Published: November 2020

Volume 1 presents first fundamental principles of the rheology of polymeric fluid including kinematics and stresses of a deformable body, the continuum theory for the viscoelasticity of flexible homogeneous polymeric liquids, the molecular theory for the viscoelasticity of flexible homogeneous polymeric liquids, and the experimental methods for the measurement of the rheological properties of poylmeric liquids. The materials presented are intended to set a stage for the subsequent chapters by introducing the basic concepts and principles of rheology, from both phenomenological and molecular perspectives, ofstructurally simple flexible and homogeneous polymeric liquids. Next, this volume presents the rheological behavior of structurally complex polymeric materials including miscible polymer blends, block copolymers, liquid-crystalline polymers, thermoplastic polyurethanes, immiscible polymer blends, perticulare-filled polymers, organoclay nanocomposites, molten polymers with dissolved gas, and thermosts.
Relationships Between Polymer Rheology and Polymer Processing
Authors: Han Chang Dae
Published: November 2020

Polymer products have long been used for a variety of applications in our daily lives, as well as for some more exotic applications, such as biomedical devices, superhigh- speed airplanes, and outer-space vehicles. Other applications are too numerous to mention them all here. There are many steps involved in the production of polymer products, from the synthesis of raw materials to the manufacturing of the finished products. Of the many steps involved, the fabrication (processing) step plays a pivotal role in determining the quality of the final products. Successful processing of polymeric materials requires a good understanding of their rheological behavior (Han 1976, 1981). Thus, intimate relationships exist between polymer rheology and polymer processing. In this chapter we describe briefly some of these close relationships between polymer rheology and polymer processing. Rheology is the science that deals with the deformation and flow of matter. Hence, polymer rheology is the science that deals with the deformation and flow of polymeric materials. Since there are a variety of polymeric materials, we can classify polymer rheology further into different categories, depending upon the nature of the polymeric materials; for instance, (1) the rheology of homogeneous polymers, (2) the rheology of miscible polymer blends, (3) the rheology of immiscible polymer blends, (4) the rheology of particulate-filled polymers, (5) the rheology of fiberglass-reinforced polymers, (6) the rheology of organoclay nanocomposites, (7) the rheology of polymeric foams, (8) the rheology of thermosets, (9) the rheology of block copolymers, and (10) the rheology of liquid-crystalline polymers. Each of these polymeric materials exhibits its own unique rheological characteristics. Thus, different theories are needed to interpret the experimental results of the rheological behavior of different polymeric materials. However, at present we do not have a comprehensive theory that can describe the rheological behavior of some polymeric materials and thus we must resort to empirical correlations to interpret the experimentally observed rheological behavior of those materials. It is then fair to state that a complete understanding of the rheological behavior of all polymeric materials remains quite a challenge indeed.
Continuum Theories for the Viscoelasticity of Flexible Homogeneous Polymeric Liquids
Authors: Han Chang Dae
Published: November 2020

There are two primary reasons for seeking a precise mathematical description of the constitutive equations for viscoelastic fluids, which relate the state of stress to the state of deformation or deformation history. The first reason is that the constitutive equations are needed to predict the rheological behavior of viscoelastic fluids for a given flow field. The second reason is that constitutive equations are needed to solve the equations of motion (momentum balance equations), energy balance equations, and/or mass balance equations in order to describe the velocity, stress, temperature, and/or concentration profiles in a given flow field that is often encountered in polymer processing operations. There are two approaches to developing constitutive equations for viscoelastic fluids: one is a continuum (phenomenological) approach and the other is a molecular approach. Depending upon the chemical structure of a polymer (e.g., flexible homopolymer, rigid rodlike polymer, microphase-separated block copolymer, segmented multicomponent polymers, highly filled polymer, miscible polymer blend, immiscible polymer blend), one may take a different approach to the formulation of the constitutive equation. In this chapter we present some representative constitutive equations for flexible, homogeneous viscoelastic liquids that have been formulated on the basis of the phenomenological approach. In the next chapter we present the molecular approach to the formulation of constitutive equations for flexible, homogeneous viscoelastic fluids. In the formulation of the constitutive equations using a phenomenological approach, emphasis is placed on the relationship between the components of stress and the components of the rate of deformation (or strain) or deformation (or strain) history, such that the responses of a fluid to a specified flow field or stress can adequately be described. The parameters appearing in a constitutive equation are supposed to represent the characteristics of the fluid under consideration. More often than not, the parameters appearing in a phenomenological constitutive equation are determined by curve fitting to experimental results. Thus phenomenological constitutive equations shed little light on the effect of the molecular parameters of the fluid under investigation to the rheological responses of the fluid.
Rheology of Flexible Homopolymers
Authors: Han Chang Dae
Published: November 2020

Numerous flexible homopolymers and flexible random copolymers are commercially available. Thus, understandably, a number of research groups have reported on the rheological behavior of flexible homopolymers and flexible random copolymers in the bulk and solution states. There are too many studies to cite them all here. In Chapters 3 to 5 we presented the rheological behavior, in general terms, of linear flexible homopolymers in steady-state shear flow, elongational flow, and/or oscillatory shear flow. In this chapter, we present the effects of temperature, molecular weight (although in Chapter 4 we presented theoretical predictions of the effect of molecular weight), and molecular weight distribution on the rheological behavior of linear flexible homopolymers, and also flexible homopolymers with long-chain branching. The rheological behavior of much more complex polymer systems is presented in other chapters of this volume. From the point of view of polymer processing, temperature is one of the most important variables that greatly affect the rheological behavior of polymeric liquids. Therefore, it is very important to present the effect of temperature on rheological behavior, placing emphasis on the methods that enable one to obtain temperature-independent correlations for rheological properties. Such correlations, when available, will help one to estimate the rheological properties of the same polymer without conducting additional experiments. With respect to polymer synthesis and polymer processing, a better understanding of the effects of molecular weight and molecular weight distribution on the rheological behavior of a polymer is of fundamental importance. In Chapter 4 we have presented molecular theory, demonstrating that the molecular weight of a linear flexible homopolymer has a profound influence on its rheological properties. Thus, information on the relationships between molecular weight and rheology, when available, will help one to choose, with little waste of time and effort, optimum processing conditions. One of the common features of all commercial homopolymers is that they are polydisperse and, therefore, it is not difficult to surmise that the molecular weight distribution of a polymer also has a profound influence on its rheological properties.
Rheology of Molten Polymers with Solubilized Gaseous Component
Authors: Han Chang Dae
Published: November 2020

Polymer melts (or polymer solutions) with a solubilized gaseous component (which occur under sufficiently high pressures, thus forming homogeneous mixtures), and polymer melts (or polymer solutions) with dispersed gas bubbles (thus forming heterogeneous mixtures of polymeric fluid and gas bubbles) are encountered in thermoplastic foam processing and polymer devolatilization. Thus, a good understanding of the rheological behavior of such mixtures is very important to the design of processing equipment and successful optimization of such polymer processing operations. From the 1950s through the 1970s, the dynamics of a single, spherical gas bubble dispersed in a stationary Newtonian or viscoelastic medium was extensively reported in the literature (Barlow and Langlois 1962; Duda and Vrentas 1969; Epstein and Plesset 1950; Folger and Goddard 1970; Marique and Houghton 1962; Plessst and Zwick 1952; Rosner and Epstein 1972; Ruckenstein and Davis 1970; Scriven 1959; Street 1968; Street et al. 1971; Tanasawa and Yang 1970; Ting 1975; Yang and Yeh 1966; Yoo and Han 1982; Zana and Leal 1975). While such investigations are of fundamental importance in their own right, they are not much help to describe bubble dynamics in thermoplastic foam extrusion or structural foam injection molding, for instance. There is no question that an investigation of bubble dynamics in a flowing molten polymer with dispersed gas bubbles is a very difficult subject by any measure. Thus, understandably, a relatively small number of research publications on bubble dynamics in a flowing molten polymer have been reported (Han and Villamizar 1978; Han et al. 1976; Yoo and Han 1981). The complexity of the problem arises from other related issues, such as the solubility and diffusivity of gaseous component(s) in a flowing molten polymer, which in turn depend on temperature and pressure of the system. Further, a gaseous component solubilized in molten polymer in the upstream side of a die, for instance, may nucleate as the pressure of the fluid stream decreases along the die axis, after which they could grow continuously as the molten polymer with dispersed gas bubbles flows through the rest of the die.
Tubular Film Blowing
Authors: Han Chang Dae
Published: November 2020

Tubular film blowing has long been used to produce biaxially oriented films using such thermoplastic polymers as low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP). Here, LDPE refers to a polymer that is synthesized by free-radical polymerization under high pressure (Fawcett et al. 1937). The discovery of linear low-density polyethylene (LLDPE) in the 1980s via the Unipol process (Beret et al. 1986; Jones et al. 1985), which uses a low-pressure gas-phase process, has led to additions to the family of tubular blown films during the past two decades. The discovery of metallocene catalysts (Stevens and Neithamer 1991; Welborn and Ewen 1994) in the 1990s further increased the number of LLDPEs that have been used to produce tubular blown films during the last decade. To distinguish LLDPE from LDPE, LLDPE is sometimes referred to as low-pressure low-density polyethylene (LP-LDPE) and LDPE is referred to as high-pressure low-density polyethylene (HP-LDPE) (see Chapter 6 of Volume 1). In this chapter, however, we use the terminologies LDPE and LLDPE. As described in Chapter 6 of Volume 1, LDPE has a high degree of long-chain branching, while LLDPE has short-chain branching with little or no longchain branching. However, the metallocene catalysts apparently allow one to produce LLDPEs having a wide range of side chains, including a certain degree of long-chain branching. The details of the synthetic procedures for producing such a variety of LLDPEs are closely guarded industrial secrets. Biaxially oriented film can be strong and tough in all directions in the plane of the film. As in fiber spinning, the polymer melt exiting from the die flows under a mechanical tension in the direction of flow. However, in the film blowing process, the tube of molten polymer is extended in both the transverse and the axial (machine) directions. Therefore, rheologically speaking, the film blowing process may be treated from the point of view of biaxial elongational flow, whereas the fiber spinning process may be treated from the point of view of uniaxial elongational flow.
Sex and Drugs
Authors: Li Jie Jack
Published: November 2020

The word aphrodisiac comes from the name of Aphrodite, the Greek goddess of sexual love, fertility, and beauty. An aphrodisiac is any drug that arouses the sexual instinct. Throughout recorded history, humans have gone to great lengths in pursuing enhancement of sexual activity and desire. In Shakespeare’s Midsummer Night’s Dream (II, i), Oberon begged for the love potion:… Fetch me that flower; the herb I show’d thee once: The juice of it on sleeping eyelid laid Will make a man or woman madly dote Upon the next live creature that it sees… Perhaps the best-known aphrodisiac is alcohol, which was recognized thousands of years ago for its possible aphrodisiac properties. Shakespeare described the effect of liquor through the porter in Macbeth (II, iii):… Lechery, Sir, it provokes, and unprovokes; It provokes the desire, But it takes away the performance. Therefore much drink may be said to be an equivocator with lechery; It makes him, and it mars him; It sets him on, and it takes him off; It persuades him, and disheartens him; Makes him stand to, and not stand to; In conclusion, equivocates him in a sleep, and, Giving him the lie, leaves him…. Aphrodisiacs are not a mere recreational curiosity in medicine; they may genuinely help some patients on antidepressants who suffer decreased libido as a side effect. According to the mechanisms of action, libido lifters can be divided into seven categories:… 1. Serotonin antagonists: cyproheptadine and granisetron 2. Adrenergic antagonists: yohimbine and trazodone 3. Cholinergic agonists: bethanechol chloride 4. Dopamine-enhancing drugs: bupropion, amantadine, and bromocriptine 5. Autoreceptor agonists: buspirone and pindolol 6. Stimulants: amphetamine, methylphenidate, and ephedrine 7. Herbals: ginkgo biloba and L-arginine… Aphrodisiacs can be obtained from plants and animals or made through chemical synthesis. Although many aphrodisiacs have not been rigorously proven effective in clinical trials, in reality, a psychological boost is likely enough to help, because many sexual problems are “in the mind” anyway.
Ligand Substitution Reactions
Authors: Jordan Robert B.
Published: November 2020

In ligand substitution reactions, one or more ligands around a metal ion are replaced by other ligands. In many ways, all inorganic reactions can be classified as either substitution or oxidation-reduction reactions, so that substitution reactions represent a major type of inorganic process. Some examples of substitution reactions follow: The operational approach was first expounded in 1965 in a monograph by Langford and Gray. It is an attempt to classify reaction mechanisms in relation to the type of information that kinetic studies of various types can provide. It delineates what can be said about the mechanism on the basis of the observations from certain types of experiments. The mechanism is classified by two properties, its stoichiometric character and its intimate character. The Stoichiometric mechanism can be determined from the kinetic behavior of one system. The classifications are as follows: 1. Dissociative (D): an intermediate of lower coordination number than the reactant can be identified. 2. Associative (A): an intermediate of larger coordination number than the reactant can be identified. 3. Interchange (I): no detectable intermediate can be found. The intimate mechanism can be determined from a series of experiments in which the nature of the reactants is changed in a systematic way. The classifications are as follows: 1. Dissociative activation (d): the reaction rate is more sensitive to changes in the leaving group. 2. Associative activation (a): the reaction rate is more sensitive to changes in the entering group. This terminology has largely replaced the SN1, SN2 and so on type of nomenclature that is still used in physical organic chemistry. These terminologies are compared and further explained as follows: Dissociative [D = SN1 (limiting)]: there is definite evidence of an intermediate of reduced coordination number. The bond between the metal and the leaving group has been completely broken in the transition state without any bond making to the entering group. Dissociative interchange (1d= SN1): there is no definite evidence of an intermediate. In the transition state, there is a large degree of bond breaking to the leaving group and a small amount of bond making to the entering group.
Kinetics in Heterogeneous Systems
Authors: Jordan Robert B.
Published: November 2020

In this Chapter, a heterogeneous system is one in which the reactants are present in at least two phases. The discussion will concentrate on two such conditions, two-phase gas/liquid systems and three-phase gas/liquid/solid systems. Chemists tend to favor homogeneous conditions, with the reactants all in one phase, because they provide more controlled and reproducible conditions. However, heterogeneous conditions are often preferred in industrial processes because of the ease of separating the catalyst from the products. In many mechanistic studies, heterogeneity adds a complicating feature to be avoided, but there are times when this cannot be done, or when it happens unexpectedly. In gas/liquid systems, the gas often has limited solubility in the liquid which contains the other reagents. As a consequence, there can be problems of mass transport of the gaseous reactant from the gas to the liquid phase. Mass transport can limit the concentration of the gas in the liquid and/or become a rate-limiting feature of the system. These features can confuse interpretations of product distributions and rate laws. The gas/liquid/solid systems generally involve reactants in the gas and liquid phases and a catalyst as the solid phase. In some cases, the solid may be produced from initially homogeneous conditions, and a question arises as to whether the real catalyst is the original species added or the solid product formed under the reaction conditions. There are further questions about the factors that may control the rate of the catalytic process. In the chemistry laboratory, these systems are most often encountered with the gases H2 or CO reacting with substrate and possibly a catalyst in the liquid phase. For the mechanistic interpretation of kinetic observations, an important factor is the rate of mass transfer of the gas to the liquid phase. The rate of gas absorption into the liquid is typically represented as a first order process, driven by the difference between the saturated gas concentration [G(I)]f and the concentration at any time [G(I)], as given by where kLA is an effective first-order rate constant. This constant is taken as a product of an inherent absorption rate constant, kL, and something related to the surface area of the liquid phase, A.
America Abroad
Authors: Raustiala Kal
Published: November 2020

The single most important feature of American history after 1945 was the United States’s assumption of hegemonic leadership. Europeans had noted America’s enormous potential since at least the nineteenth century. After the Civil War the United States had one of the largest economies in the world, but, as noted earlier in this book, in geopolitical terms it remained a surprisingly minor player. By 1900 the United States was playing a more significant political role. But it was only after 1945 that the nation’s potential on the world stage was fully realized. Victory in the Second World War left the United States in an enviable position. Unlike the Soviet Union, which endured devastating fighting on its territory and lost tens of millions of citizens, the United States had experienced only one major attack on its soil. Thanks to its actions in the war America had great influence in Europe. And the national economy emerged surprisingly vibrant from the years of conflagration, easily dominant over any conceivable rival or set of rivals. When the First World War ended the United States ultimately chose to return to its hemispheric perch. It declined to join the new League of Nations, and rather than maintaining engagement with the great powers of the day, America generally turned inward. The years following the Second World War were quite different. In addition to championing—and hosting—the new United Nations, the United States quickly established a panoply of important institutions aimed at maintaining and organizing international cooperation in both economic and security affairs. Rising tensions with the Soviet Union, apparent to many shortly after the war’s end, led the United States to remain militarily active in both Europe and Asia. The intensifying Cold War cemented this unprecedented approach to world politics. The prolonged occupations of Germany and Japan were straightforward examples of this newly active global role. In both cases the United States refashioned a conquered enemy into a democratic, free-market ally—a significant feat. The United States did not, however, seek a formal empire in the wake of its victory.
Frontotemporal Dementia
Authors: Blass David M.
Published: November 2020

Frontotemporal dementia (FTD) is a family of neurodegenerative diseases and syndromes that most commonly involve the frontal and temporal lobes, producing dramatic alterations of personality, behavior, language, and other cognitive abilities (McKhann et al., 2001). Age of onset tends to be younger than in Alzheimer’s disease (AD), with most patients becoming symptomatic in the sixth decade of life. Although population-based epidemiologic studies of FTD have found a prevalence of approximately 5–10 per 100,000 in patients 50 years of age and older, autopsy-based case series have found that approximately 5% to15% of people with dementia have FTD, a discrepancy suggesting that many cases go undiagnosed during life (Rosso et al., 2003). Recent advances in clinicopathologic correlation have revealed that a number of neurologic conditions previously conceived of as independent disease entities such as progressive supranuclear palsy (PSP), corticobasilar degeneration (CBD), and hippocampal sclerosis dementia are in many cases better classified in the FTD family (McKhann et al., 2001; Blass et al., 2004). Many patients with FTD develop other neurologic syndromes as well, including parkinsonism and amyotrophic lateral sclerosis (ALS). FTD is actually a group of clinical syndromes with overlapping neuropathologies. The clinical expression of the disease relates primarily to the anatomic location of disease involvement rather than the neuropathologic subtype; there are many such subtypes. Clinical variants are most distinct early in the disease course, when the degree of anatomic involvement may be limited to discrete regions. As the disease spreads through the brain, many patients have symptoms that become complex and take on char acteristics of other variants. The first clinical FTD variant is one in which behavioral abnormalities and personality changes dominate the clinical presentation. This syndrome is usually associated with disease involvement of the frontal and anterior temporal lobes. In addition, there are two language presentations: primary progressive aphasia and semantic dementia (McKhann et al., 2001). The neurologic syndromes of PSP, CBD, and ALS with dementia are familiar to the neurologist because of their neurologic symptoms; it is noteworthy that patients with any of the previously mentioned syndromes routinely develop the psychiatric symptoms reviewed below.
Huntington’s Disease
Authors: Rosenblatt Adam
Published: November 2020

Huntington’s disease (HD) is a hereditary neurodegenerative disorder characterized by the triad of a movement disorder, dementia, and various psychiatric disturbances. HD is caused by the abnormal expansion of a trinucleotide (CAG) repeat in the huntingtin gene of chromosome 4—a mutation that is inherited as an autosomal dominant. When the number of CAG repeats exceeds 39, the individual harboring it goes on to develop HD. The most common time of onset is in the fourth or fifth decade, but the age of onset is inversely correlated with the size of the triplet repeat expansion. In rare instances, persons with very large expansions may have onset in childhood, and those with expansions only just into the abnormal range may have onset late in life. Children of affected fathers, if they receive the abnormal allele, tend to inherit an allele that is even further expanded, and thus usually experience the onset of symptoms at a younger age than their fathers; this phenomenon is known as paternal anticipation. The progression of HD is inexorable and usually leads to death within 15 to 20 years of symptom onset; patients in the final stages have severe dementia and are unable to speak, eat, or purposefully move. Death typically results from the consequences of immobility such as pneumonia or malnutrition. The movement disorder of HD has two major manifestations: involuntary movements (eg, chorea, dystonia) and impairments of voluntary movement (eg, clumsiness, dysarthria, swallowing difficulties, falls, bradykinesia, rigidity). Chorea generally predominates early in the course and is gradually eclipsed by motor impairment as the disease becomes more advanced. In the end stages, patients are rigid and immobile. A variety of medications are used to suppress chorea in HD, including neuroleptics, benzodiazepines, and dopamine-depleting agents such as tetrabenazine, but it remains controversial whether these agents convey functional, as opposed to cosmetic, benefits. HD, like many other neurodegenerative disorders, is associated with a variety of psychiatric problems. Some of these problems such as insomnia or demoralization may be thought of as nonspecific. They have a variety of causes and are associated with many different medical conditions.
Tourette’s Syndrome
Authors: Walkup John T. , Schneider Benjamin N.
Published: November 2020

Tourette’s syndrome (TS) is a neuropsychiatric disorder of childhood onset characterized by the presence of motor and vocal tics for a duration of at least 1 year. Tics are typically brief and stereotypical movements (eg, eye blinking, head jerks) or vocalizations (eg, throat clearing, grunting), but they can also be more complex movements involving multiple muscle groups and combinations of movements and sounds. There is a great range of tic severity. Tics can be so subtle or occur so infrequently as to be unnoticeable, even to the person with the tics. However, tics can also be so intense and frequent that they are readily noticeable by others, and they can be disruptive of daily activities. Indeed, in some cases (eg, severe head jerks), tics can cause pain or physical injury (eg, cervical disc and spine damage). Tics usually begin in childhood; the average age at diagnosis is 7 years. They reach peak severity in the early teen years and then lessen in intensity and frequency during young adulthood (Leckman et al., 2001). Tics wax and wane in severity, worsening with excitement and stress and improving during calm, focused activities. Coprolalia and its motor counterpart copropraxia (uttering obscene words or making obscene gestures, respectively) are uncommon symptoms, occurring in less than 10% of patients with TS and are not required for a diagnosis of TS (Robertson and Stern, 1998). Many patients describe a sensation or urge prior to tic occurrence, commonly referred to as a premonitory sensation or urge (Miguel et a1., 2000). Even though tics are considered involuntary, they can be voluntarily suppressed for short periods of time. Prevalence estimates of TS have varied and depend a great deal on the threshold for diagnosis and setting in which cases are identified. A review of the many epidemiologic studies suggests that 0.1% to 1% of people are affected with TS (Scahill et al., 2005). Despite this variability in specific rates, epidemiologic studies have consistently identified that males are more commonly affected than females, children are more frequently affected than adults, and that milder forms of TS are more common than severe forms.
Lessons from History
Authors: Marschark Marc , Lang Harry G. , Albertini John A.
Published: November 2020

The adage “those who do not learn from history are doomed to repeat it” is a powerful one for parents and teachers of deaf students. Myths that have grown from ignorance have dogged us in this field as far back as we can see, and faulty assumptions and overgeneralizations have been sustained through time. A study of history also reveals what at first might seem like a series of random events, but which actually manifest patterns that have influenced today’s educational policy (see Fischer & Lane, 1993; Van Cleve, 1993). These patterns are related to several themes critical to the emphases of this book. One such theme is the importance of parental involvement in the education of deaf children. History provides us with factual accounts and anecdotes that enrich our understanding of the advocacy roles parents have played, especially with regard to the establishment of school programs. As we shall see, research clearly supports the role of parental involvement in both formal and informal education, as evidenced in studies demonstrating the long-term influence of mother-child relationships and early communication and the need for providing deaf children with a variety of experiences during the early years. Another theme that emerges from a historical perspective relates to how deaf people have taken an increasingly greater role in influencing their own education. Histories have been published that describe how deafness was perceived in ancient times, how various societies changed with regard to their attitudes toward deaf people, and that highlight the turning points in the education and acceptance of people who are deaf. In most published histories of deaf education, we see the long-standing conflicts through the centuries pertaining to sign language and spoken communication philosophies and the contributions of the individuals who founded school programs or attempted to teach deaf children. Often, however, writers have neglected to examine how deaf people themselves have overcome barriers in many periods of history and under a wide variety of conditions to make important contributions in education and other fields. A history of the education of deaf individuals thus should be more than just a study of changes in educational practices.
Characteristics of Deaf Learners
Authors: Marschark Marc , Lang Harry G. , Albertini John A.
Published: November 2020

In the interests of equality, sensitivity, and political correctness, it is often claimed that deaf and hearing individuals are exactly the same, except for their hearing losses. To some extent, this attitude may reflect an understandable swing of the pendulum after years of society’s treating deaf individuals as though they are deficient. At the same time, we believe that there is now considerable evidence to indicate that the experiences, knowledge, and strategies of deaf individuals often differ in some ways from those of hearing individuals, and that such differences are likely to influence learning. At one level, the question of differences between deaf and hearing learners is a statistical, descriptive one. This chapter provides some basic information in that regard, including demographics, types and causes of hearing loss, and issues relating to educational placement. We discuss populations and their characteristics. At another level, however, the question of differences between deaf and hearing learners is about individuals. There, the relevant issues are more empirical than descriptive, and an interdisciplinary perspective becomes important. If deaf and hearing students were the same except for their hearing losses, then we would not have to worry about special educational methods, issues of social integration, or whether a local public school or special school program would be better for a deaf child. If deaf and hearing children were the same except for their hearing losses, we could put them in the same classrooms and assume the same background knowledge, social skills, and educational futures. The problem is that life is rarely so simple. By virtue of their hearing losses, many deaf children (and particularly those with hearing parents) have somewhat different early environments than hearing children. Frequently, those children do not have access to the language of their families, and their parents are not fully prepared for handling the special needs of a child who cannot hear. With differences in communication, early social interactions, and ways of acquiring new information, it seems likely that deaf children will have some characteristics that distinguish them from hearing children.
Education Begins at Home
Authors: Marschark Marc , Lang Harry G. , Albertini John A.
Published: November 2020

Parents, siblings, and others provide young children with a context in which development occurs and supports and promotes early learning. In this chapter, we consider the roles of various individuals and early interventions in social, language, and cognitive development before children enter school. Because most deaf children are born to nonsigning, hearing parents, communication in the home is given special consideration, particularly with regard to the kinds of information and experience that contribute to those domains. We also consider the importance of implicit instruction in relation to fostering educational readiness and the potential effects on long-term academic achievement and personal growth. Parents will encounter both opportunities and challenges in raising a deaf child, and research has demonstrated a variety of ways in which they can optimize their child’s development. Therefore, we devote some space to describing the field on which early development takes place. Most important, we will see the importance of deaf children having early access to language, social interaction, and experiential diversity. Because most cases of deafness are not hereditary, many deaf children will have congenital or early-onset hearing losses that are totally unexpected (and usually unrecognized for some time) by their parents. Some of those children will be considered at risk at birth because of the maternal, fetal, or neonatal medical problems that contributed to their hearing losses. Beyond the consequences of initial medical difficulties, factors related to prenatal or postnatal hearing loss may well influence the quantity or quality of interactions the infant has with others in the environment during the first few months. These earliest influences, and their effects, can have ever-widening consequences for development over the first months and years of life. Even before birth, sounds perceived from within the womb can influence the course of development. Early in the last trimester of pregnancy, a fetus will rotate and adopt a new position with the head against the mother’s pelvis. Most fetuses already have considerable responsiveness to sound at this point and can perceive the mother’s voice and heartbeat through bone conduction (Als et al., 1979).