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Segregation
Kinds of Segregation Terms modified by Segregation Selected AbstractsMEASURING OCCUPATIONAL SEX SEGREGATION: ACADEMIA IN AUSTRALIAN UNIVERSITIES, 1989 TO 2000ECONOMIC PAPERS: A JOURNAL OF APPLIED ECONOMICS AND POLICY, Issue 3 2002JUDITH RICH First page of article [source] SIZE-AND AGE-CLASS SEGREGATION OF BOWHEAD WHALES SUMMERING IN NORTHERN FOXE BASIN: A PHOTOGRAMMETRIC ANALYSISMARINE MAMMAL SCIENCE, Issue 2 2003Susan E. Cosens Abstract To determine whether Hudson Bay-Foxe Basin bowhead whales segregate on the basis of age, whales summering in northern Foxe Basin, were aerially photographed in August of 1996, 1997, and 1998. Image lengths on either the negatives or contact prints were measured and total body lengths were estimated. In all three years the majority of whales photographed were ,13.5 m long. Calves and juveniles made up 89.3%, 96.6%, and 79.3% of the total number of measured whales in 1996 (n = 28), 1997 (n = 30) and 1998 (n = 29) respectively. The number of bowheads >13.5 m, the approximate size at which females reach sexual maturity, that were photographed was directly proportional to the number of calves photographed. Our results indicate that northern Foxe Basin bowheads are part of a more widely distributed stock. Adult males and resting adult females apparently summer in another part of the range, probably northwestern Hudson Bay. Northern Foxe Basin appears to be used as a summer feeding area by cows with young-of-the-year calves and by juveniles. [source] Segregation and scheduling for P2P applications with the interceptor middleware systemCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 6 2008Cosimo Anglano Abstract Very large size peer-to-peer systems are often required to implement efficient and scalable services, but usually they can be built only by assembling resources contributed by many independent users. Among the guarantees that must be provided to convince these users to join the P2P system, particularly important is the ability of ensuring that P2P applications and services run on their nodes will not unacceptably degrade the performance of their own applications because of an excessive resource consumption. In this paper we present the Interceptor, a middleware-level application segregation and scheduling system, which is able to strictly enforce quantitative limitations on node resource usage and, at the same time, to make P2P applications achieve satisfactory performance even in face of these limitations. A proof-of-concept implementation has been carried out for the Linux operating system, and has been used to perform an extensive experimentation aimed at quantitatively evaluating the Interceptor. The results we obtained clearly demonstrate that the Interceptor is able to strictly enforce quantitative limitations on node resource usage, and at the same time to effectively schedule P2P applications. Copyright © 2007 John Wiley & Sons, Ltd. [source] Diversity and composition of Arctiidae moth ensembles along a successional gradient in the Ecuadorian AndesDIVERSITY AND DISTRIBUTIONS, Issue 5 2005Nadine Hilt ABSTRACT Andean montane rain forests are among the most species-rich terrestrial habitats. Little is known about their insect communities and how these respond to anthropogenic habitat alteration. We investigated exceptionally speciose ensembles of nocturnal tiger moths (Arctiidae) at 15 anthropogenically disturbed sites, which together depict a gradient of forest recovery and six closed-forest understorey sites in southern Ecuador. At weak light traps we sampled 9211 arctiids, representing 287 species. Arctiid abundance and diversity were highest at advanced succession sites, where secondary scrub or young forest had re-established, followed by early succession sites, and were lowest, but still high, in mature forest understorey. The proportion of rare species showed the reverse pattern. We ordinated moth samples by non-metric multidimensional scaling using the chord-normalized expected species shared index (CNESS) index at various levels of the sample size parameter m. A distinct segregation of arctiid ensembles at succession sites from those in mature forest consistently emerged only at high m -values. Segregation between ensembles of early vs. late succession stages was also clear at high m values only, and was rather weak. Rare species were responsible for much of the faunal difference along the succession gradient, whereas many common arctiid species occurred in all sites. Matrix correlation tests as well as exploration of relationships between ordination axes and environmental variables revealed the degree of habitat openness, and to a lesser extent, elevation, as best predictors of faunal dissimilarity. Faunal differences were not related to geographical distances between sampling sites. Our results suggest that many of the more common tiger moths of Neotropical montane forests have a substantial recolonization potential at the small spatial scale of our study and accordingly occur also in landscape mosaics surrounding nature reserves. These species contribute to the unexpectedly high diversity of arctiid ensembles at disturbed sites, whereas the proportion of rare species declines outside mature forest. [source] An Economic Model of Friendship: Homophily, Minorities, and SegregationECONOMETRICA, Issue 4 2009Sergio Currarini We develop a model of friendship formation that sheds light on segregation patterns observed in social and economic networks. Individuals have types and see type-dependent benefits from friendships. We examine the properties of a steady-state equilibrium of a matching process of friendship formation. We use the model to understand three empirical patterns of friendship formation: (i) larger groups tend to form more same-type ties and fewer other-type ties than small groups, (ii) larger groups form more ties per capita, and (iii) all groups are biased towards same-type relative to demographics, with the most extreme bias coming from middle-sized groups. We show how these empirical observations can be generated by biases in preferences and biases in meetings. We also illustrate some welfare implications of the model. [source] Black Employment, Segregation, and the Social Organization of Metropolitan Labor MarketsECONOMIC GEOGRAPHY, Issue 3 2007Niki T. Dickerson Abstract: This broad analysis of the employment of blacks in metropolitan areas examines the role of residential segregation in comparison with four other key structural explanations for racial metropolitan inequality: industrial composition, minority concentration, immigration, and the racial disparity in skills. The goal of the analysis was to determine whether the spatial configuration of blacks relative to whites in a metropolitan area influences the employment rates of black men and black women in the context of the structural conditions of the local labor market. The study expanded the analysis of space and work beyond an emphasis on the physical distance between black communities and jobs to a broader conceptualization of residential segregation as a structural feature of the entire metropolitan labor market that is representative of its social organization with regard to race. Using a longitudinal data set of the structural characteristics of the 95 largest U.S. cities from the 1980, 1990, and 2000 decennial censuses, the study used a cross-sectional analysis of the cities in 2000 and a fixed-effects analysis to assess the impact of five dimensions of residential segregation and the four other structural factors on the employment of blacks across different labor markets and across time within each labor market. The results revealed that when the other structural characteristics are controlled, the employment rates of blacks are lower in more segregated cities and decrease as cities become more segregated over time. The clustering and evenness dimensions of residential segregation were the most determinative of black employment. [source] Local Housing Markets and Segregation in EnglandECONOMIC OUTLOOK, Issue 1 2005Article first published online: 2 FEB 200 In this article, Geoff Meen discusses patterns of economic segregation in England. Despite the emphasis that the government places on reducing segregation, patterns have, in fact, remained remarkably constant over, at least, the last twenty years. Dynamic changes in housing markets and migration over time help to explain these patterns, and evidence is presented on the extent to which house prices in certain local authorities have been under- or over-valued. The analysis also shows that, at the local level, housing markets exhibit non-linear behaviour, which hinders the effectiveness of housing policy in the most deprived areas and adds to economic segregation. [source] Segregation of temporal and spatial distribution between kleptoparasites and parasitoids of the eusocial sweat bee, Lasioglossum malachurum (Hymenoptera: Halictidae, Mutillidae)ENTOMOLOGICAL SCIENCE, Issue 2 2009Carlo POLIDORI Abstract Cuckoo bees and velvet ants use different resources of their shared host bees, the former laying eggs on the host pollen stores and the latter on immature stages. We studied the activity patterns of the cuckoo bee Sphecodes monilicornis and the velvet ant Myrmilla capitata at two nesting sites of their host, the social digger bee Lasioglossum malachurum, over a 3 year period. Due to the difference in host exploitation, we expected different temporal patterns of the two natural enemies as well as a positive spatial association with host nest density for both species. At a daily level, S. monilicornis was more abundant between 10.00 and 15.00 h, while M. capitata was most active in the early morning and late afternoon; both species activities were independent from host provisioning activity. The activity of cuckoo bees was in general positively correlated with the density of open host nests (but not with the total number of nests), while that of velvet ants was rarely correlated with this factor. Sphecodes monilicornis was seen both attacking the guard bees and directly entering into the host nests or digging close to nest entrances, while M. capitata only gained access to host nests through digging. We conclude that the temporal and spatial segregation between the two species may be, at least partially, explained both by the different resources exploited and by the different dynamics of host interactions. [source] Sex Differences in Feeding Activity Results in Sexual Segregation of Feral GoatsETHOLOGY, Issue 5 2008Robin I. M. Dunbar Sexual segregation is common in ungulates. We show, in a high latitude population of feral goats where behavioural synchrony and fission rates have been shown to be the best explanation for segregation, that it is differences explicitly in the feeding time requirements of the two sexes (but not those for other activities) that best explains the variations in monthly frequencies of segregation. However, this effect is less marked during winter months when short day length forces the time budgets of the two sexes to converge. We argue that the various explanations for segregation can best be interpreted as separate factors in a multivariate model in which species- and habitat-specific weightings influence the relative importance of these variables, and thus the likelihood that segregation will occur. [source] Age-Related Microhabitat Segregation in Willow Tit Parus montanus Winter FlocksETHOLOGY, Issue 11 2000Lluís Brotons It is expected that through flexibility in behaviour, flock living birds respond to the asymmetries in resource access derived from dominance relationships. We analysed the microhabitat use of willow tits in winter flocks and assessed possible factors which shape habitat segregation between adults and juveniles in different temperature regimes. When foraging in mild conditions (ambient temperature >,0°C), flocks split up into subgroups with adults foraging in inner parts of trees more often than juveniles. However, no differences were recorded in the vertical position occupied in trees. In harsh conditions (< , 4°C), flocks re-united and juveniles further moved to outer parts of trees, increasing horizontal segregation between age classes. In mild conditions, vigilance behaviour was not related to the position of birds in trees, but in harsh conditions, scanning frequency was higher in outer parts of trees only for adults. In mild weather, juvenile position in trees was associated with body size and mass. The foraging microhabitat segregation detected in harsh conditions fits the age-related hoarding distribution previously described in the same population. This supports the hypothesis that hoarded food is important in determining future foraging habitat use. Adult preference and intraspecific competition for safer or richer inner parts of trees as foraging sites during harsh conditions seems to determine the habitat segregation between adults and juveniles. Furthermore, we suggest that in mild weather, when foraging in the absence of adults, juveniles balance the costs of using a potentially dangerous microhabitat with the benefits of building energetically cheap and large food reserves through hoarding. The expected patterns of microhabitat segregation may differ in parids, depending on whether predation risk or other factors such as food availability are the main factors controlling habitat quality. [source] Segregation of two endocannabinoid-hydrolyzing enzymes into pre- and postsynaptic compartments in the rat hippocampus, cerebellum and amygdalaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2004A. I. Gulyas Abstract Fatty acid amide hydrolase (FAAH) and monoglyceride lipase (MGL) catalyse the hydrolysis of the endocannabinoids anandamide and 2-arachidonoyl glycerol. We investigated their ultrastructural distribution in brain areas where the localization and effects of cannabinoid receptor activation are known. In the hippocampus, FAAH was present in somata and dendrites of principal cells, but not in interneurons. It was located mostly on the membrane surface of intracellular organelles known to store Ca2+ (e.g. mitochondria, smooth endoplasmic reticulum), less frequently on the somatic or dendritic plasma membrane. MGL immunoreactivity was found in axon terminals of granule cells, CA3 pyramidal cells and some interneurons. In the cerebellum, Purkinje cells and their dendrites are intensively immunoreactive for FAAH, together with a sparse axon plexus at the border of the Purkinje cell/granule cell layers. Immunostaining for MGL was complementary, the axons in the molecular layer were intensively labelled leaving the Purkinje cell dendrites blank. FAAH distribution in the amygdala was similar to that of the CB1 cannabinoid receptor: evident signal in neuronal somata and proximal dendrites in the basolateral nucleus, and hardly any labelling in the central nucleus. MGL staining was restricted to axons in the neuropil, with similar relative signal intensities seen for FAAH in different nuclei. Thus, FAAH is primarily a postsynaptic enzyme, whereas MGL is presynaptic. FAAH is associated with membranes of cytoplasmic organelles. The differential compartmentalization of the two enzymes suggests that anandamide and 2-AG signalling may subserve functional roles that are spatially segregated at least at the stage of metabolism. [source] Mechanisms of time-based figure,ground segregationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2003Farid I. Kandil Abstract Figure,ground segregation can rely on purely temporal information, that is, on short temporal delays between positional changes of elements in figure and ground (Kandil, F.I. & Fahle, M. (2001) Eur. J. Neurosci., 13, 2004,2008). Here, we investigate the underlying mechanisms by measuring temporal segregation thresholds for various kinds of motion cues. Segregation can rely on monocular first-order motion (based on luminance modulation) and second-order motion cues (contrast modulation) with a high temporal resolution of ,,20 ms. The mechanism can also use isoluminant motion with a reduced temporal resolution of 60 ms. Figure,ground segregation can be achieved even at presentation frequencies too high for human subjects to inspect successive frames individually. In contrast, when stimuli are presented dichoptically, i.e. separately to both eyes, subjects are unable to perceive any segregation, irrespective of temporal frequency. We propose that segregation in these displays is detected by a mechanism consisting of at least two stages. On the first level, standard motion or flicker detectors signal local positional changes (flips). On the second level, a segregation mechanism combines the local activities of the low-level detectors with high temporal precision. Our findings suggest that the segregation mechanism can rely on monocular detectors but not on binocular mechanisms. Moreover, the results oppose the idea that segregation in these displays is achieved by motion detectors of a higher order (motion-from-motion), but favour mechanisms sensitive to short temporal delays even without activation of higher-order motion detectors. [source] ADAPTIVE MIGRATORY DIVERGENCE AMONG SYMPATIRIC BROK CHARR POPULATIONSEVOLUTION, Issue 3 2005Dylan J. Fraser Abstract Ecological processes clearly contribute to population divergence, yet how they interact over complex life cycles remains poorly understood. Notably, the evolutionary consequences of migration between breeding and nonbreeding areas have received limited attention. We provide evidence for a negative association between interpopulation differences in migration (between breeding and feeding areas, as well as within each) and the amount of gene flow (m) among three brook charr (Salvelinus fontinalis) populations inhabitingMistassini Lake, Quebec, Canada. Individuals (n=1166) captured throughout lake feeding areas over two consecutive sampling years were genotyped (10 microsatellites) and assigned to one of the three populations. Interpopulation differences in migration were compared based on spatial distribution overlap, habitat selection, migration distance within feeding areas, and morphology. We observed a temporally stable, heterogeneous spatial distribution within feeding areas among populations, with the extent of spatial segregation related to differential habitat selection (represented by littoral zone substrate). Spatial segregation was lowest and gene flow highest (m=0.015) between two populations breeding in separate lake inflows. Segregation was highest and gene flow was lowest (mean m=0.007) between inflow populations and a third population breeding in the outflow. Compared to outflow migrants, inflow migrants showed longer migration distances within feeding areas(64,70 km vs. 22 km). After entering natal rivers to breed, inflow migrants also migrated longer distances (35,75 km) and at greater elevations (50,150 m) to breeding areas than outflow migrants (0,15 km; ,10,0 m). Accordingly, inflow migrants were more streamlined with longer caudal regions, traits known to improve swimming efficiency. There was no association between the geographic distance separating population pairs and the amount of gene flow they exchanged. Collectively, our results are consistent with the hypothesis that reduced gene flow between these brook charr populations results from divergent natural selection leading to interpopulation differences in migration. They also illustrate how phenotypic and genetic differentiation may arise over complex migratory life cycles. [source] Gremmeniella abietina types cannot be distinguished using ascospore morphologyFOREST PATHOLOGY, Issue 6 2006A. Uotila Summary Twenty-one Gremmeniella abietina var. abietina type A and 12 type B samples with ripened apothecia were collected in Sweden and Finland. Morphological dimensions of the ascospores were determined with an image analyser (Leica Qwin). Measured variables included length, width, perimeter and roundness of ascospores. Variations in these variables overlapped between the two types. Type A ascospores were significantly shorter (mean length 15.8 ,m) than the type B ascospores (mean length 17.1 ,m). Type A ascospores were also significantly rounder than type B ascospores. Differences between these morphological characters were, however, too small to distinguish the types as separate taxonomical species. Round-pointed and acute ascospores were found in the same apothecium but in different asci. According to the hypervariable marker GAAA1000, both round-pointed and acute ascospores originated from the same two parents in normal segregation. Résumé Vingt-et-un échantillons avec des apothécies matures du type A de Gremmeniella abietina var. abietina et 12 du type B ont été récoltés en Suède et Finlande. Les dimensions morphologiques des ascospores ont été déterminées avec un analyseur d'images (Leica Qwin). Les variables mesurées sont la longueur, la largeur, le périmètre et la rondeur des spores. Les gammes de variation de ces différentes variables se recouvrent entre les deux types. Les ascospores de type A sont significativement plus courtes (longueur moyenne de 15.8 ,m) que les ascospores de type B (longueur moyenne de 17.1 ,m). Les ascospores de type A sont aussi significativement plus rondes que celles de type B. Les différences pour ces caractères morphologiques sont toutefois trop faibles pour distinguer les types comme des espèces taxonomiques différentes. Des ascospores arrondies et pointues ont été trouvées dans la même apothécie mais dans des asques différents. En se basant sur le marqueur hypervariable GAAA1000, on peut établir que les ascospores arrondies et pointues proviennent des mêmes deux parents en ségrégation normale. Zusammenfassung In Schweden und Finnland wurden 21 Gremmeniella abietina var. abietina Typ A- und 12 Typ B- Proben mit reifen Apothecien gesammelt. Folgende morphologische Messgrössen der Ascosporen wurden mit einem Image Analyser (Leica Quin) bestimmt: Länge, Breite, Umfang und Form. Die Variation der Variablen überlappte bei den beiden Typen. Die Typ A-Ascosporen waren signifikant kürzer (15,8 ,m mittlere Länge) als die Typ B-Ascosporen (17,1 ,m). Der Typ A hatte signifikant rundere Ascosporen als der Typ B. Die Unterschiede in den morphologischen Merkmalen waren jedoch zu gering, um zwei taxonomische Arten zu unterscheiden. Ascosporen mit runden und spitzen Enden wurden im gleichen Apothecium, jedoch in verschiedenen Asci gefunden. Mit dem hypervariablen Marker GAAA1000 erwiesen sich Ascosporen mit rundem und spitzem Ende als Nachkommen der gleichen Eltern mit normaler Segregation. [source] Absence of residual effects of a defeated resistance gene in poplarFOREST PATHOLOGY, Issue 2 2003K.-S. Woo Summary In a few plant pathosystems, defeated major genes have been shown to contribute to partial resistance to disease. This hypothesis has never been tested before in a forest tree, but pathogenic variation associated with recent hybridization in poplar rust in the Pacific northwest provided an opportunity. An F2 progeny of 256 poplar clones in the field near Corvallis, Oregon, USA, has been monitored for rust severity and infection type since the advent of the new hybrid rust, Melampsora × columbiana, in the mid-1990s. All 256 clones displayed a susceptible infection type in 1997 and again in 2000, and yet variation in uredinial density (i.e. partial resistance) was still observed. To determine which clones possessed a defeated resistance gene, a greenhouse inoculation was performed with an isolate of M. medusae, one of the parents of M. × columbiana. Clones that would have been resistant to M. medusae, prior to the advent of M. × columbiana, were thus identified. The inoculation resulted in a 1 : 1 segregation (,2=0.772; p=0.38) for resistance, indicating the presence of a major gene. However, the F2 clones possessing the defeated resistance gene displayed the same level of partial resistance in the field in both 1997 and 2000 as their full siblings lacking the gene. Résumé Chez quelques pathosystèmes végétaux, il a été montré que le contournement de gènes majeurs de résistance contribue à une résistance partielle envers la maladie. Cette hypothèse n'a encore jamais été testée chez un arbre forestier, mais le changement de pouvoir pathogène associéà l'hybridation récente de la rouille du peuplier dans le nord-ouest des USA en a fourni l'occasion. Une descendance F2 de 256 clones de peuplier a été suivie au champ près de Corvallis, Oregon, USA, pour la gravité de la rouille et le type d'infection, depuis l'apparition du nouvel hybride Melampsora x columbiana, dans les années 1990. Tous les 256 clones se sont montrés sensibles en 1997 et à nouveau en 2000, et une variation dans la densité des urédies (résistance partielle) a aussi été observée. Pour déterminer quels clones présentaient une résistance contournée, des inoculations ont été réalisées en serre avec un isolat de Melampsora medusae originaire du Kentucky. Des clones qui étaient résistants àM. medusae avant l'apparition de M. x columbiana ont ainsi été identifiés. Les inoculations ont abouti à une ségrégation 1 :1 (,2 = 0,772; P = 0,38) pour la résistance, ce qui indique la présence d'un gène majeur. Cependant, les clones F2 possédant le gène de résistance contourné montraient le même niveau de résistance partielle au champ en 1997 et 2000 que leurs plein-frères qui n'avaient pas ce gène. Zusammenfassung Für einige Pflanzen-Pathosysteme wurde gezeigt, dass unwirksam gewordene Haupt-Resistenzgene immer noch zu einer teilweisen Resistenz beitragen. Für Waldbäume wurde diese Hypothese bisher nie überprüft. Dies wurde jetzt im pazifischen Nordwesten möglich, wo der Pappelrost nach einem rezenten Hybridisierungsereignis stark variierte. An den F2-Nachkommenschaften von 256 Pappelklonen, die unter Freilandbedingungen in der Nähe von Corvallis, Oregon, USA wuchsen, wurde nach dem Auftreten des neuen Hybridrostes (Melampsora × columbiana) ab ca. 1990 die Krankheitsintensität und der Infektionstyp registriert. Alle 256 Klone zeigten einen anfälligen Infektionstyp im Jahre 1997 und dann wieder im Jahre 2000. Dabei wurde eine Variation in der Urediendichte (d.h. partielle Resistenz) beobachtet. Um zu bestimmen, welche Klone ein unwirksam gewordenes Resistenzgen besitzen, wurden Inokulationen im Gewächshaus mit einem Isolat von M. medusae, einem Elter von M. × columbiana, durchgeführt. Damit wurden Klone identifiziert, die vor dem Auftreten von M. × columbiana gegen M. medusae resistent waren. Der Infektionsversuch führte zu einer 1:1 Segregation (,2=0,772; P=0,38) für die Resistenz, was auf das Vorliegen eines Hauptgens hinweist. Die F2-Klone, welche dieses überwundene Resistenzgen besitzen, zeigten jedoch unter Feldbedingungen in den Jahren 1997 und 2000 den gleichen Grad einer Teilresistenz wie ihre Vollgeschwister, welchen dieses Gen fehlt. [source] Occupational Segregation and the Tipping Phenomenon: The Contrary Case of Court Reporting in the USAGENDER, WORK & ORGANISATION, Issue 2 2007Joyce P. Jacobsen The ,tipping' phenomenon, whereby an occupation switches from dominance by one demographic group to dominance by another, has occurred in various occupations. Multiple causes have been suggested for such switches, including several related to technological change, both through effects on the performance of the work and through the effect of changing demand for different occupations. The court reporting occupation provides a novel setting for testing the relevance of various proposed causes for the increased feminization of many occupations. In this case, many of the general correlates, including declining wages, are not found; rather the phenomenon is related to the earlier feminization of the clerical workforce and the increased identification of court reporting with clerical work. [source] The Impact of Occupational Sex Segregation on Family Businesses: The Case of American Harness RacingGENDER, WORK & ORGANISATION, Issue 4 2006Elizabeth A. Larsen Previous research on occupational sex segregation agrees that the workplace is not an isolated world but instead influences, and is influenced by, other spheres of social life. Identifying specific social factors both internal and external to the workplace, and how these may interact, can provide deeper insights into how occupational sex segregation is created and maintained. This study focuses on individual family businesses in American harness horse racing, a previously unexamined and highly sex-segregated industry, and provides insights in how vertical and horizontal sex segregation may develop in family businesses. The findings show how the belief that married couples cannot debate and resolve work-related conflicts without undue strain on their personal relationship leads some of these couples to organize their work into gendered tasks and workspaces, contributing to the maintenance of vertical segregation in the trainer position. The implications for segregation of other solutions, such as operating separate businesses, or working for another business, are less clear. [source] Going Against the Historical Grain: Perspectives on Gendered Occupational Identity and Resistance to the Breakdown of Occupational Segregation in Two Manufacturing FirmsGENDER, WORK & ORGANISATION, Issue 3 2002Anne-marie Greene This article discusses a process of restructuring of working practices within two manufacturing firms with respect to its implications for gendered occupational segregation. A contextualized, historically situated analysis is presented, which is cast within debates on the nature of gendered occupational identity, equality initiatives and arenas of power and influence for women and men, within what were traditionally male-dominated organizational contexts. Such an analysis serves to highlight the significance of the new restructuring in sweeping away 150 years of practice and embedded ,ways of doing things' and offers explanations for the actions of contemporary men and women in opposing what were seen by management and the trade union as emancipatory changes. [source] Occupational Sex Segregation and Part-time Work in Modern BritainGENDER, WORK & ORGANISATION, Issue 2 2001Louisa Blackwell It is often argued that women's full-time work is becoming less gender segregated, while their part-time work becomes more so. This article looks cross-sectionally and longitudinally at the relationship between occupational sex segregation and part-time work. An innovative application of segregation curves and the Gini index measures segregation between women full-timers and men and between women part-timers and men. Both fell between 1971 and 1991, as did overall occupational sex segregation. These results were used to contextualize a longitudinal analysis showing how shifts between full-time and part-time hours affected women's experiences of occupational sex segregation and vertical mobility. Human capital explanations see full-time and part-time workers as distinct groups whose occupational choices reflect anticipated family roles. The plausibility of this emphasis on long-term strategic planning is challenged by substantial and characteristic patterns of occupational mobility when women switch between full-time and part-time hours. The segmented nature of part-time work meant that women who switched to part-time hours, usually over child rearing, were often thrown off their occupational path into low-skilled, feminized work. There was some ,occupational recovery' when they resumed full-time work. [source] A Surface-Based Approach to Measuring Spatial SegregationGEOGRAPHICAL ANALYSIS, Issue 2 2007David O'Sullivan Quantitative indices of residential segregation have been with us for half a century, but suffer significant limitations. While useful for comparison among regions, summary indices fail to reveal spatial aspects of segregation. Such measures generally consider only the population mix within zones, not between them. Zone boundaries are treated as impenetrable barriers to interaction between population subgroups, so that measurement of segregation is constrained by the zoning system, which bears no necessary relation to interaction among population subgroups. A segregation measurement approach less constrained by the chosen zoning system, which enables visualization of segregation levels at the local scale and accounts for the spatial dimension of segregation, is required. We propose a kernel density estimation approach to model spatial aspects of segregation. This provides an explicitly geographical framework for modeling and visualizing local spatial segregation. The density estimation approach lends itself to development of an index of spatial segregation with the advantage of functional compatibility with the most widely used index of segregation (the dissimilarity index D). We provide a short review of the literature on measuring segregation, briefly describe the kernel density estimation method, and illustrate how the method can be used for measuring segregation. Examples using a simulated landscape and two empirical cases in Washington, DC and Philadelphia, PA are presented. [source] Phase Segregation in Thin Films of Conjugated Polyrotaxane, Poly(ethylene oxide) Blends: A Scanning Force Microscopy Study,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2007L. Sardone Abstract Scanning force microscopy (SFM) is used to study the surface morphology of spin-coated thin films of the ion-transport polymer poly(ethylene oxide) (PEO) blended with either cyclodextrin (CD)-threaded conjugated polyrotaxanes based on poly(4,4,-diphenylene-vinylene) (PDV), ,-CD,PDV, or their uninsulated PDV analogues. Both the polyrotaxanes and their blends with PEO are of interest as active materials in light-emitting devices. The SFM analysis of the blended films supported on mica and on indium tin oxide (ITO) reveals in both cases a morphology that reflects the substrate topography on the (sub-)micrometer scale and is characterized by an absence of the surface structure that is usually associated with phase segregation. This observation confirms a good miscibility of the two hydrophilic components, when deposited by using spin-coating, as suggested by the luminescence data on devices and thin films. Clear evidence of phase segregation is instead found when blending PEO with a new organic-soluble conjugated polymer such as a silylated poly(fluorene)- alt -poly(para -phenylene) based polyrotaxane (THS,,-CD,PF,PPP). The results obtained are relevant to the understanding of the factors influencing the interfacial and the intermolecular interactions with a view to optimizing the performance of light-emitting diodes, and light-emitting electrochemical cells based on supramolecularly engineered organic polymers. [source] Reading, Writing, and Segregation: A Century of Black Women Teachers in Nashville by Sonya RamseyHISTORY OF EDUCATION QUARTERLY, Issue 1 2010ADAM FAIRCLOUGH First page of article [source] When Parallel Paths Cross: Competition and the Elimination of Sex Segregation in the Education Fraternities, 1969-1974HISTORY OF EDUCATION QUARTERLY, Issue 2 2003Laurie Moses Hines First page of article [source] Vertical Social Differentiation in Athens: Alternative or Complement to Community Segregation?INTERNATIONAL JOURNAL OF URBAN AND REGIONAL RESEARCH, Issue 4 2001Thomas Maloutas Vertical social differentiation is presented in the recent literature as an important element of reduced segregation in South European cities, and the supporting evidence originates mainly from Athens. The authors of this article question the claim about the common form and function of vertical social differentiation across South Europe, as well as its opposition to community segregation, and try to reveal the specificity of the processes leading to its formation in Athens. Since the mid-1970s, the dominant process of urban growth in Athens has been middle-class suburbanization. This process has reinforced community segregation and, at the same time, has triggered a filtering-down process in wide areas around the CBD, formerly occupied by upper and mainly intermediate professional categories. Interclass vertical segregation has subsequently appeared in these areas, where intermediate professional categories and lower middle-class households are now predominant. The fact that these areas do not represent a real choice for any of their resident groups shows that this vertical cohabitation has been the unintended consequence of changing segregation patterns, and hardly the outcome or the corollary of a growing process of sociospatial homogenization. Dans les textes récents, la différenciation sociale verticale est présentée comme un facteur important dans la réduction de la ségrégation urbaine en Europe du Sud, les éléments probants provenant essentiellement d'Athènes. Cet article conteste l'idée que la différenciation sociale verticale ait une forme ou une fonction commune en Europe méridionale, et qu'elle entrave la ségrégation horizontale; de plus, il tente d'exposer la spécificité des processus qui conduisent à sa formation à Athènes. Depuis le milieu des années 1970, l'expansion urbaine de la capitale grecque se caractérise par l'implantation en banlieue des classes supérieurs et moyennes. Ce processus a renforcé la ségrégation dans les quartiers et, parallèlement, a déclenché un processus de filtrage vers le bas dans de vastes zones entourant l'hypercentre, précédemment occupées par des catégories de professionnels libéraux supérieures et surtout moyennes. Une ségrégation verticale interclasse est ensuite apparue dans ces quartiers, des catégories de libéraux moyennes et des ménages de la petite bourgeoisie y prédominant désormais. Or, quel que soit le groupe de résidents, ces zones ne représentent pas un choix réel; cette cohabitation verticale est donc bien la conséquence imprévue de la modification des schémas de ségrégation, plutôt que le résultat ou le corollaire d'une homogénéisation socio-spatiale accentuée. [source] On the Segregation of Genetically Modified, Conventional and Organic Products in European Agriculture: A Multi-market Equilibrium AnalysisJOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2005GianCarlo Moschini Q1; O3 Abstract Evaluating the possible benefits of the introduction of genetically modified (GM) crops must address the issue of consumer resistance as well as the complex regulation that has ensued. In the European Union (EU), this regulation envisions the co-existence of GM food with conventional and quality-enhanced products, mandates the labelling and traceability of GM products and allows only a stringent adventitious presence of GM content in other products. All these elements are brought together within a partial equilibrium model of the EU agricultural food sector. The model comprises conventional, GM and organic food. Demand is modelled in a novel fashion, whereby organic and conventional products are treated as horizontally differentiated but GM products are vertically differentiated (weakly inferior) relative to conventional ones. Supply accounts explicitly for the land constraint at the sector level and for the need for additional resources to produce organic food. Model calibration and simulation allow insights into the qualitative and quantitative effects of the large-scale introduction of GM products in the EU market. We find that the introduction of GM food reduces overall EU welfare, mostly because of the associated need for costly segregation of non-GM products, but the producers of quality-enhanced products actually benefit. [source] Workforce Segregation and the Gender Wage Gap: Is "Women's" Work Valued as Highly as "Men's"?,JOURNAL OF APPLIED SOCIAL PSYCHOLOGY, Issue 6 2008Christine Alksnis This study focuses on gender segregation and its implications for the salaries assigned to male- and female-typed jobs. We used a between-subjects design to examine whether participants would assign different pay to 3 types of jobs wherein the actual responsibilities and duties carried out by men and women were the same, but the job was situated in either a traditionally masculine or traditionally feminine domain. We found pay differentials between jobs defined as "male" and "female," which suggest that gender-based discrimination, arising from occupational stereotyping and the devaluation of the work typically done by women, influences salary allocation. The ways in which the results fit with contemporary theorizing about sexism and with the shifting standards model (Biernat, 1995, 2003) are discussed. [source] Spontaneous segregation on a hybrid chiral surfaceJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 10 2008Szabelski Abstract Segregation of enantiomers in two-dimensional adsorbed layers is a process that is usually controlled by anisotropic directional interactions between adsorbed molecules. In this contribution, we propose a simple theoretical model in which the chiral segregation occurs even though the lateral interactions are neglected. In particular, we consider a solid surface composed of two domains with different patterns of active sites being mirror images of each other. The domains of opposite handedness represent crystal facets of a composite chiral material which are adjoined to form a heterochiral adsorbing surface. To explore equilibrium properties of the system, we use Canonical Ensemble Monte Carlo method for a square lattice. The influence of factors such as energetic properties of the surface and density of the adsorbed layer on the extent of separation is examined. The obtained results indicate that effective two-dimensional separation on the hybrid chiral surface assumed in our model can be achieved only at sufficiently low adsorbate densities. The results also suggest that the segregation on the hybrid surface would be a promising method of enantiodiscrimination for those chiral molecules which do not exhibit strong lateral interactions. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008 [source] Density segregation in vibrated granular beds with bumpy surfacesAICHE JOURNAL, Issue 10 2010Eldin Wee Chuan Lim Abstract Segregation of granular materials by virtue of density or size is a commonly encountered phenomenon in nature. Despite its widespread interest among many researchers in recent years, a complete and unified understanding of granular segregation remains elusive to date. Using molecular dynamics simulations, we report a novel technique of inducing density segregation in a binary mixture of granular materials subjected to vibrations by the use of a bumpy vibrating base. Density segregation in the vertical directions may be induced by oscillating the bumpy base composed of discrete solid particles vertically or horizontally. In both cases, lighter particles tended to rise to the top of the granular bed and form a layer above the heavier particles. We suggest that differences in granular temperature profiles arising from the two different modes of vibrations may play an important role in determining the extent of density segregation occurring in binary granular mixtures. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Atomistic Modeling Study of Surface Segregation in Nd:YAGJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2006Ulrich Aschauer This study investigates the composition of free surfaces of neodymium-doped yttrium,aluminum,garnet, using energy minimization techniques. Atomistic modeling shows that the dopant is concentrated in a zone within 5 Å of the surface, the enrichment factor being around 1300 when comparing surfaces with bulk concentrations. It is shown that the (111) surface can incorporate 1.8 times as much Nd as the (110) surface, the latter commonly found in YAG morphologies. Our results indicate that by using nanocrystalline ceramics and by modifying crystal growth to form (111) surfaces, the Nd content and thus the laser power may be significantly increased. [source] The Geography of Opportunity and Unemployment: An Integrated Model of Residential Segregation and Spatial MismatchJOURNAL OF URBAN AFFAIRS, Issue 4 2005Michael Howell-Moroney Using National Longitudinal Survey of Youth (1979) data, I estimate a two-step model that separately models the effects of segregation and spatial mismatch. The first model predicts educational attainment as a function of exposure to residential segregation as a youth. The second model predicts unemployment probability as an adult as a function of educational attainment and spatial mismatch. The empirical results show that segregation does have discernable effects on educational attainment for blacks, but not for whites. I also find that spatial mismatch affects unemployment probability for blacks, but such an effect is hardly present for whites. A partial equilibrium analysis using predictions from the models shows that large changes in either segregation levels or the central city/suburban distribution of the black population would yield only moderate decreases in unemployment probability for the black population overall. Yet despite small predicted effects, these results should be viewed with caution because the general equilibrium effects of a large scale movement of blacks and whites across metropolitan space are largely impossible to predict with current data. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||