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This chapter tells the story of the long struggle to overturn Plessy v. Ferguson and desegregate American schools - culminating with the Supreme Court’s unanimous opinion Brown v. Board of Education. The chapter then examines the application of Brown, detailing how subsequent rulings purporting to stem from Brown have, in fact, failed to carry out its central command to desegregate all American schools. Much of this checkered legal history arose due to the Court’s insistence on delineating between de jure (legally mandated) and de facto (arising incidentally as a result of non-legally mandated conduct) segregation This distinction led to the 2007 PICS ruling, which dramatically circumscribes the use of race to achieve a desegregated educational environment for districts which experience de facto rather than de jure discrimination. The chapter concludes with an analysis of the growing “resegregation” of American schools, tracing its deleterious effects on all students.
Severe phase coarsening and separation in Sn–Bi alloys have brought increasing reliability concern in microelectronic packages. In this study, a phase field model is developed to simulate the microstructural evolution and evaluate the change in macroscopic physical properties of the flip chip Cu/Sn58Bi/Cu joint under the conditions of isothermal aging, as well as the coupled loads of elastic stress and electric current stressing. Results show that large-sized Bi-rich phase particles grow up at the expense of small-sized ones. Under the coupled loads, Bi atoms migrate along the electron flow direction, consequently Bi-rich phase segregates to form a Bi-rich phase layer at the anode. The current crowding ratio in the solder decreases rapidly first and then fluctuates slightly with time. Current density and von Mises stress exhibit inhomogeneous distribution, and both of them are higher in the Sn-rich phase than in the Bi-rich phase. Electric current transfers through the Sn-rich phase and detours the Bi-rich phase. As time proceeds, the resistance of the solder joint increases, and the average von Mises stress of the solder joint decreases. The Bi-rich phase coarsens much faster under the coupled loads than under the conditions of isothermal aging.
We introduce an efficient, automated computational approach for analyzing interfaces within atom probe tomography datasets, enabling quantitative mapping of their thickness, composition, as well as the Gibbsian interfacial excess of each solute. Detailed evaluation of an experimental dataset indicates that compared with the composition map, the interfacial excess map is more robust and exhibits a relatively higher resolution to reveal compositional variations. By field evaporation simulations with a predefined emitter mimicking the experimental dataset, the impact of trajectory aberrations on the measurement of the thickness, composition, and interfacial excess of the decorated interface are systematically analyzed and discussed.
The microstructure and distribution of the elements have been studied in thin films of a near-equimolar CrNbTaTiW high entropy alloy (HEA) and films with 8 at.% carbon added to the alloy. The films were deposited by magnetron sputtering at 300°C. X-ray diffraction shows that the near-equimolar metallic film crystallizes in a single-phase body centered cubic (bcc) structure with a strong (110) texture. However, more detailed analyses with transmission electron microscopy (TEM) and atom probe tomography (APT) show a strong segregation of Ti to the grain boundaries forming a very thin Ti–Cr rich interfacial layer. The effect can be explained by the large negative formation enthalpy of Ti–Cr compounds and shows that CrNbTaTiW is not a true HEA at lower temperatures. The addition of 8 at.% carbon leads to the formation of an amorphous structure, which can be explained by the limited solubility of carbon in bcc alloys. TEM energy-dispersive X-ray spectroscopy indicated that all metallic elements are randomly distributed in the film. The APT investigation, however, revealed that carbide-like clusters are present in the amorphous film.
Research has shown that white Americans oppose welfare spending in part due to their racial prejudices. Yet, this conventional wisdom ignores the importance of local geography in determining whether whites are likely to view welfare in racialized terms. This article demonstrates that the effect of prejudice on whites’ welfare preferences depends on the salience of welfare's racialized image in a given geographic context. I present a novel application of the racial threat hypothesis—conceptualizing both prejudice and place as multidimensional—to argue that the racial geography of an area amplifies the effect of traditional racial stereotypes on welfare preferences, whereas economic geography amplifies the effect of symbolically racist attitudes. I test these propositions using geocoded data from the years following the 1996 U.S. welfare policy reforms. My analysis reveals that racial attitudes are more predictive of welfare preferences not simply where the stigmas of welfare are salient due to a large black population or high poverty rate, but more specifically where residential segregation makes black or poor households more visible from the viewpoint of whites. These findings highlight the subjectivity of the white perspective, and call for more scholarship theorizing whites’ agency in seeing racialized issues as threatening to white interests.
Ethnic diversity is generally associated with less social capital and lower levels of trust. However, most empirical evidence for this relationship is focused on generalized trust, rather than more theoretically appropriate measures of group-based trust. This article evaluates the relationship between ethnic diversity – at the national, regional and local levels – and the degree to which coethnics are trusted more than non-coethnics, a value referred to here as the ‘coethnic trust premium’. Using public opinion data from sixteen African countries, this study finds that citizens of ethnically diverse states express, on average, more ethnocentric trust. However, within countries, regional ethnic diversity is associated with less ethnocentric trust. This same negative pattern between diversity and ethnocentric trust appears across districts and enumeration areas within Malawi. The article then shows, consistent with these patterns, that diversity is only detrimental to intergroup trust at the national level when ethnic groups are spatially segregated. These results highlight the importance of the spatial distribution of ethnic groups on intergroup relations, and question the utility of micro-level studies of interethnic interactions for understanding macro-level group dynamics.
Ashley Smith’s experience in the adult prison system flowed from certain of its systemic features. This article considers whether and how it is possible to reconcile the basic commitments of sentencing law, including the legal aims of punishment, with that systemic portrait. The youth court that ordered Smith’s transfer to adult custody relied upon an idealized conception of adult imprisonment, just as ordinary adult sentencing courts do. Judges purport to stipulate the severity of punishment, but tend not to consider how prison conditions will shape the severity of the sanction. Even where a particular defendant is likely to face unique difficulties in custody, courts tend to take notice in limited and rare ways. Smith’s experience in adult custody challenges us to more clearly identify, and to consider extending, doctrinal sentencing rules that represent a judicial concern with the effects and prospects of imprisonment in particular cases.
The death of Ashley Smith represents the first time in Canadian legal history that correctional officers were criminally charged in the death of a prisoner under the care of the state. In response to these unprecedented charges, the Union of Canadian Correctional Officers (UCCO) mounted a highly public campaign in defense of the officers. In this article, I review UCCO’s media statements following Smith’s death, submissions to various government review committees, and the current Global Agreement between UCCO and Correctional Service Canada (CSC) regarding federally sentenced women. I suggest these narratives work to reproduce administrative segregation as necessary to manage “troubled young women” who are constituted as an unsafe working condition for officers. I highlight the failure of UCCO to influence government policy, unlike the effective success of unions in the United States, and I challenge the place of UCCO in Canada’s trade union movement.
This article examines the history of debates around the creation of a ‘native village’ in Pietermaritzburg culminating in the construction of the city's first formal township. This, and the decision to locate the new township next to the city's main dump, have commonly been interpreted to corroborate Maynard Swanson's influential concept of the ‘sanitation syndrome’. Swanson first coined that term to explain the origins of racial segregation in Durban, but it struck a chord very widely, not only because it problematized science as metaphorical, but also because it shifted responsibility for the antecedents of apartheid onto urban, self-styled progressive English-speaking officials and voters. From the Pietermaritzburg evidence, however, I argue that the concept ‘sanitation syndrome’ now unhelpfully elides or oversimplifies a complex history. I thus question its continued utility as a critique of cultural racism within liberal or modernization discourses in the wider contemporary regional context.
In this paper we consider a system of reaction–diffusion–advection equations with a free boundary, which arises in a competition ecological model in heterogeneous environment. The evolution of the free-boundary problem is discussed, which is an extension of the results of Du and Lin (Discrete Contin. Dynam. Syst. B19 (2014), 3105–3132). Precisely, when u is an inferior competitor, we prove that (u, v) → (0, V) as t→∞. When u is a superior competitor, we prove that a spreading–vanishing dichotomy holds, namely, as t→∞, either h(t)→∞ and (u, v) → (U, 0), or limt→∞h(t) < ∞ and (u, v) → (0, V). Moreover, in a weak competition case, we prove that two competing species coexist in the long run, while in a strong competition case, two species spatially segregate as the competition rates become large. Furthermore, when spreading occurs, we obtain some rough estimates of the asymptotic spreading speed.
The generation of granitic magmas begins with melting in the lower crust, under active participation of the underlying mantle. Thermally driven, melting is a pervasive and continuous process that develops over a wide region. In contrast, the building of a granitic pluton is highly discontinuous in time and space. Several inputs of magma, sometimes with a different chemical compositions, are focused toward a region where they accumulate, forming a large pluton, often separated by some 50 km from an adjacent one. The switch from a continuous to a discontinuous process represents a fundamental point of magma generation. It gives place to the modified model m(M-SAE), in which the mantle (m) and Melting (M) are separated from the Segregation (S), Ascent (A) and Emplacement (E) modes. Discontinuities result from non-linear processes that develop during segregation and ascent of the magma. They rely on the non-linear rheology of partially molten rocks. Thresholds control the change from a solid-like to liquid-like behaviour of the magma. In between, the rheology exhibits sudden jumps between states. Because two phases continuously coexist (matrix and melt), strain is highly partitioned between them. This may induce highly discontinuous melt segregation, which needs both pure and simple shear to develop. Melt focusing is controlled by the viscosity contrast between the two phases. It gives rise to different compaction lengths depending on the region, a partially melting source or a nearly brittle crust, where it develops. Because ascent and emplacement are discontinuous in time, this allows the crust to relax, avoiding the room problem for a pluton intruding the upper crust. Intermediate magma chambers could develop with different temperature and magma composition. They could be the place of enhanced magma mixing. Finally, the stress conditions, which differ for each tectonic setting, influence the shape of the granitic body.
Racial integration has been a tenet of educational equity for over fifty years. Despite this, U.S. higher education presents staggering rates of segregation. Strikingly, there is little scholarship to answer the question of how integrated colleges segregated? I interrogate the process of segregation over a fifty-year period through a comparative historical analysis of the broader field of higher education and case studies of three nineteenth-century colleges. Through analysis of independently collected archival materials, I show that local-level organization of racial contact fails to account for the success or failure of racial integration in schools. Instead, I show that the interaction between colleges—and the emergence of a competitive field of higher education—undermined even successfully integrated campuses. Mesolevel practices are important for revealing how organizational actors implement rationalized cultural ideas as well as how local-level ideas are negotiated in a situated field. The growth of intercollegiate college competition differentiated not only particular types of education but also consecrated groups of people. Further, this reveals the production of cultural meanings around race as a differentiation strategy in response to interorganizational competition.
This paper examines the racial ecology of lead exposure as a form of environmental inequity, one with both historical and contemporary significance. Drawing on comprehensive data from over one million blood tests administered to Chicago children from 1995-2013 and matched to over 2300 geographic block groups, we address two major questions: (1) What is the nature of the relationship between neighborhood-level racial composition and variability in children’s elevated lead prevalence levels? And (2) what is the nature of the relationship between neighborhood-level racial composition and rates of change in children’s prevalence levels over time within neighborhoods? We further assess an array of structural explanations for observed racial disparities, including socioeconomic status, type and age of housing, proximity to freeways and smelting plants, and systematic observations of housing decay and neighborhood disorder. Overall, our theoretical framework posits lead toxicity as a major environmental pathway through which racial segregation has contributed to the legacy of Black disadvantage in the United States. Our findings support this hypothesis and show alarming racial disparities in toxic exposure, even after accounting for possible structural explanations. At the same time, however, our longitudinal results show the power of public health policies to reduce racial inequities.
During the first half of the twentieth century, deep structural changes occurred in the South African countryside. While farming became an important pillar of the national economy, more and more people left the land in search of better lives in towns and cities. This article examines agricultural education, an early avenue of state intervention in farming, to elucidate how officials and groups of farmers navigated the ‘agrarian question’ by trying to define the roles that men, women, blacks, and whites played in the sector's restructuring. I argue that agricultural planning was inextricable from ideologies and politics of segregation, a factor that historiography has not systematically taken into account. By comparing interventions in the Transkei and Ciskei with those in the Orange Free State, this article illuminates the interrelations between rural planning and segregation, as well as how they were complicated by delineations of class and gender.
This paper formulates a new model of racial integration for African Americans in the United States, based upon a careful consideration of the weaknesses in previous models. Instead of spatial mixing, this model of integration calls for transformed habits of interaction between citizens in public spaces, as well as a redistribution of power, understood as access to resources and opportunities. Integration along these lines would produce mutual transformation rather than compulsory assimilation. However, this model does not necessarily answer the concerns of integration critics who question the capacity of the United States to achieve true racial equality. Hence, the conclusion considers three significant obstacles to the achievement of integration, and acknowledges that unprecedented, radical transformations would be necessary to lay the groundwork for integration. In the end, both integration pessimism and a renewed commitment to integration are reasonable and defensible responses to our still-segregated present.
The present investigation addressed the weldability of Super Ni 718 alloy and AISI 316L using gas tungsten arc (GTA) welding process using three different filler wires, such as ER2594, ERNiCrMo-4 and ERNiCrCoMo-1. Interface microstructures showed the formation of secondary phases at the heat-affected zone (HAZ) of Super Ni 718 alloy and delta ferrite colonies at the HAZ of AISI 316L. It was witnessed from the weld microstructures that the deleterious phases were suppressed or controlled while using these filler wires for joining the bimetals. Tensile results corroborated that the failure occurred at the parent metal of AISI 316L in all the cases. The presence of microvoids and dimples characterized for the ductile mode of fracture in these weldments. Charpy V-notch test results showed that the weldments using ERNiCrMo-4 filler exhibited higher impact energy. A detailed study has been made to investigate the structure–property relationships of these weldments using optical and scanning electron microscopic techniques.
The share of older migrants in Dutch cities is increasing. However, only limited knowledge has been gained about the urban conditions that older migrants live in and how these compare to those of their native Dutch counterparts. This paper contributes to filling this knowledge gap using detailed information on residential patterns, housing conditions and levels of neighbourhood deprivation in the city of Amsterdam in the Netherlands, and links this information to data about housing and neighbourhood satisfaction and perceived safety. Empirical evidence demonstrates that there is strong path dependence with regard to the places in which one finds different groups of older non-Western migrants. Older non-Western migrants in Amsterdam are highly concentrated in disadvantaged neighbourhoods. The number of concentrations has increased significantly over the past decade, as well as the concentration levels. Nevertheless, we did not find indications of social isolation. With regard to housing conditions, we found better conditions for socio-economically similar groups of native Dutch and Surinamese 55+ residents, compared to Turkish and Moroccan 55+ residents. These conditions correspond with levels of housing satisfaction. Surinamese older people are more positive about their neighbourhoods. We hypothesise that this is related to the restructuring of neighbourhoods where Surinamese 55+ residents are concentrated. Although the immediate environment of older non-Western people is characterised by high levels of social deprivation, this does not translate into dissatisfaction with social relations or feelings of lack of safety. This suggests that their residential concentration in particular urban neighbourhoods may also bring significant opportunities.
The use of large groups of robots in the execution of complex tasks has received much attention in recent years. Generally called robotic swarms, these systems employ a large number of simple agents to perform different types of tasks. A basic requirement for most robotic swarms is the ability for safe navigation in shared environments. Particularly, two desired behaviors are to keep robots close to their kin and to avoid merging with distinct groups. These are respectively called cohesion and segregation, which are observed in several biological systems. In this paper, we investigate two different approaches that allow swarms of robots to navigate in a cohesive fashion while being segregated from other groups of agents. Our first approach is based on artificial potential fields and hierarchical abstractions. However, this method has one drawback: It needs a central entity which is able to communicate with all robots. To cope with this problem, we introduce a distributed mechanism that combines hierarchical abstractions, flocking behaviors, and an efficient collision avoidance mechanism. We perform simulated and real experiments to study the feasibility and effectiveness of our methods. Results show that both approaches ensure cohesion and segregation during swarm navigation.
This paper analyzes the relationship between unexplained racial/ethnic wage differentials on the one hand and social network segregation, as measured by inbreeding homophily, on the other. Our analysis is based on both the US and Estonian surveys, supplemented with the Estonian telephone communication data. In the case of Estonia we consider the regional variation in economic performance of the Russian minority, and in the US case we consider the regional variation in black--white differentials. Our analysis finds a strong relationship between the size of the wage differential and network segregation: Regions with more segregated social networks exhibit larger unexplained wage gaps.
In this paper we adjudicate between competing claims of persisting segregation and rapid integration by analyzing trends in residential dissimilarity and spatial isolation for African Americans, Hispanics, and Asians living in 287 consistently defined metropolitan areas from 1970 to 2010. On average, Black segregation and isolation have fallen steadily but still remain very high in many areas, particularly those areas historically characterized by hypersegregation. In contrast, Hispanic segregation has increased slightly but Hispanic isolation has risen substantially owing to rapid population growth. Asian segregation has changed little and remains moderate, and although Asian isolation has increased it remains at low levels compared with other groups. Whites remain quite isolated from all three minority groups in metropolitan America, despite rising diversity and some shifts toward integration from the minority viewpoint.
Multivariate analyses reveal that minority segregation and spatial isolation are actively produced in some areas by restrictive density zoning regimes, large and/or rising minority percentages, lagging minority socioeconomic status, and active expressions of anti-Black and anti-Latino sentiment, especially in large metropolitan areas. Areas displaying these characteristics are either integrating very slowly (in the case of Blacks) or becoming more segregated (in the case of Hispanics), whereas those lacking these attributes are clearly moving toward integration, often quite rapidly.