Levels Of Segregation Research Articles

Transmission of black mouth disease shed light on the aquaculture management of the sea urchin Strongylocentrotus intermedius

Mass mortality of the sea urchin Strongylocentrotus intermedius and consequent economic losses occur in the aquaculture industry due to the outbreak of black mouth disease. Decreasing the physical contact between the healthy and diseased sea urchins is proposed to be an effective approach to preventing the disease transmission. Laboratory experiments were designed to investigate whether different levels of segregation can effectively prevent the disease transmission. The present study found that the number of diseased sea urchins in the segregation with two layers of PVC net (group T) was significantly lower than that without segregation (group E) on the first day. Further, there were no significant difference in the number of diseased sea urchins between the group T and the group with healthy sea urchins (group N) on the first day. These results indicate that the segregation with two layers of PVC net, which completely eliminates the physical contact between healthy and diseased sea urchin, is an effective approach to preventing the transmission of black mouth disease of S. intermedius. However, the number of diseased sea urchins in the group T showed no significant advantage on the third and seventh day. This indicates that the effectiveness of the complete segregation for disease transmission is greatly reduced if the diseased/dead sea urchins are not removed in time. Further, no significant difference was found in the number of diseased sea urchins in the group T on the first day after the air exposure, indicating that the complete segregation is not effective to prevent the disease transmission after air exposure. Surprisingly, the morbidities of groups in the experiment 2 on the seventh day (62.5 ± 3.2%) was significantly lower than that of groups in the experiment 3 on the fifth day (95.8 ± 1.4%). This clearly indicates that air exposure deteriorates the transmission of the black mouth disease. Collectively, the present study suggests that complete segregation, which eliminates the physical contact between healthy and diseased sea urchin, is an effective approach to preventing the transmission of the black mouth disease, provided that diseased/dead sea urchins are removed in time and air exposure is avoided. In addition, the present study indicates that the physical contact between healthy and diseased sea urchins is important route of the disease transmission, although other spread routes of pathogenic bacteria are not exclusive.

Springboard, not roadblock: Discourse analysis of Facebook groups suggests that ethnic neighbourhoods in European cities might jump-start immigrants’ integration

The age of migration finds its physical manifestation in the immigrant neighbourhoods of European cities. These ‘ethnic enclaves’ have received much attention from the public, as well as policy makers. Conventional wisdom holds that policies are required to confront such concentrations. Several European countries have implemented measures to achieve a spatial balance – be it through settlement bans or allocation quotas – in the name of fostering immigrants’ integration. However, the scholarly verdict on the relationship between segregation and integration is still pending. This article aims to contribute a novel approach, namely discourse analysis of immigrants’ Facebook groups. To this end, it first establishes the level of segregation in six cities (three in Germany and three in England) using data held by municipal archives. Second, it scrutinises 119 Facebook groups of Pakistanis and Turks in these cities, with a total of 2665 posts. This exploratory analysis suggests that desegregation might be causative for downwards assimilation and transnationalism, whereas ethnic enclaves might provide the basis for a pluralist mode of integration. Therefore, it argues for a re-evaluation of the suitability of dispersal policies for shaping the transformation of ever more European cities into multi-ethnic metropolises.

A Scale-up Study on Chemical Segregation and the Effects on Tensile Properties in Two Medium Mn Steel Castings

Two ingots weighing 400 g and 5 kg with nominal compositions of Fe–8Mn–4Al–2Si–0.5C–0.07V–0.05Sn were produced to investigate the effect of processing variables on microstructure development. The larger casting has a cooling rate more representative of commercial production and provides an understanding of the potential challenges arising from casting-related segregation during efforts to scale up medium Mn steels, while the smaller casting has a high cooling rate and different segregation pattern. Sections from both ingots were homogenized at 1250 ^{circ} C for various times to study the degree of chemical homogeneity and delta -ferrite dissolution. Within 2 hours, the Mn segregation range (max–min) decreased from 8.0 to 1.7 wt pct in the 400 g ingot and from 6.2 to 1.5 wt pct in the 5 kg ingot. Some delta -ferrite also remained untransformed after 2 hours in both ingots but with the 5 kg ingot showing nearly three times more than the 400 g ingot. Micress modeling was carried out, and good agreement was seen between predicted and measured segregation levels and distribution. After thermomechanical processing, it was found that the coarse untransformed delta -ferrite in the 5 kg ingot turned into coarse delta -ferrite stringers in the finished product, resulting in a slight decrease in yield strength. Nevertheless, rolled strips from both ingots showed >900 MPa yield strength, >1100 MPa tensile strength, and >40 pct elongation with <10 pct difference in strength and no change in ductility when compared to a fully homogenized sample.

Student Assignment Policies and Racial and Income Segregation of Schools, School Attendance Zones, and Neighborhoods

Purpose: This article examines the relationship between educational and residential segregation in three school districts with differing approaches to student assignment. Racial and income segregation within school districts is often only examined at the school level, even as school patterns are often related to residential and attendance zone segregation depending on integration policies aimed at decoupling these relationships. Research Method/Approach: Using an innovative data set, the School Attendance Boundary Survey, along with Census and Common Core of Data data, this analysis examines racial and income segregation at the neighborhood, school zone, and school levels in three districts with varied student assignment policies to explore the relationship between districts’ diversity policies and school, attendance zone, and residential segregation. Findings: We find that, despite high residential segregation, educational segregation varies in these three districts. In the two districts that sought to increase diversity in their student assignment policies, educational segregation was lower than in the third district that did not consider diversity, despite similar levels of residential segregation. The findings suggest that district leaders’ use of diversity-focused student assignment policies may be one way to disrupt the link between residential and school segregation. Conclusions: Understanding the segregation of educational boundaries within school districts, and the relationship between school zone segregation and segregation at other geographic scales, offers insights into how district leaders could utilize student assignment policies to reduce racial and income segregation.

Fertility of Roma Minorities in Central and Eastern Europe

We analyse Roma fertility in four neighbouring countries in Central and Eastern Europe with a large Roma minority: in Hungary, Slovakia, Romania and Serbia. The sources of data are the respective national population censuses from 2011. Fertility is measured at the birth cohort level as the average number of children ever born. We make an international comparison of the fertility of Roma and non-Roma majority population women on the basis of completed education. In the case of Hungary, we also explore how the correlation between fertility and ethnic identity is modified when completed education and ethnic residential segregation are controlled.&#x0D; The fertility of Roma women is far above the majority population average in all birth cohorts and in each country. Educational attainment modifies this relationship. The fertility of highly educated Roma and majority population women is converging. The exposure to majority behaviour also has an effect. The lower the level of ethnic residential segregation, the smaller the difference between the fertility of Roma and majority population women. Completed education and residential segregation may exert different forces at the two ends of the educational hierarchy when their joint effect is explored. At the upper end of the social hierarchy, neither segregation nor ethnicity matters; at the lower end, however, both exposure to ethnic majority behaviour and ethnicity matter.

Mechanisms of reduced interspecific interference between territorial species

AbstractInterspecific territoriality has complex ecological and evolutionary consequences. Species that interact aggressively often exhibit spatial or temporal shifts in activity that reduce the frequency of costly encounters. We analyzed data collected over a 13-year period on 50 populations of rubyspot damselflies (Hetaerina spp.) to examine how rates of interspecific fighting covary with fine-scale habitat partitioning and to test for agonistic character displacement in microhabitat preferences. In most sympatric species, interspecific fights occur less frequently than expected based on the species’ relative densities. Incorporating measurements of spatial segregation and species discrimination into the calculation of expected frequencies accounted for most of the reduction in interspecific fighting (subtle differences in microhabitat preferences could account for the rest). In 23 of 25 sympatric population pairs, we found multivariate differences between species in territory microhabitat (perch height, stream width, current speed, and canopy cover). As predicted by the agonistic character displacement hypothesis, sympatric species that respond more aggressively to each other in direct encounters differ more in microhabitat use and have higher levels of spatial segregation. Previous work established that species with the lowest levels of interspecific fighting have diverged in territory signals and competitor recognition through agonistic character displacement. In the other species pairs, interspecific aggression appears to be maintained as an adaptive response to reproductive interference, but interspecific fighting is still costly. We now have robust evidence that evolved shifts in microhabitat preferences also reduce the frequency of interspecific fighting.

Disparities in Cancer Screening: The Role of County-Level Metropolitan Status and Racial Residential Segregation

Mortality from cervical and colorectal cancers can be reduced through routine screening, which can often be accessed through primary care. However, uptake of screening in the US remains suboptimal, with disparities observed across geographic characteristics, such as metropolitan status or level of racial residential segregation. Little is known about the interaction of metropolitan status and segregation in their relationship with cancer screening. We conducted a quantitative survey of 474 women aged 45-65 in central Pennsylvania. The survey collected county-level characteristics and participant-level demographics, beliefs, cancer screening barriers, and cervical and colorectal cancer screening. We used bivariate and multivariable logistic regression to analyze relationships between metropolitan status and segregation with screening. For cervical cancer screening, 82.8% of participants were up-to-date, which did not differ by county type in the final analysis. Higher healthcare trust, higher cancer fatalism, and reporting cost as a barrier were associated with cervical cancer screening. For colorectal cancer screening, 55.4% of participants were up-to-date, which differed by county type. In metropolitan counties, segregation was not associated with colorectal cancer screening, but in non-metropolitan counties, segregation was associated with greater colorectal cancer screening. The relationship between metropolitan status and being up-to-date with colorectal, but not cervical, cancer screening varied by segregation. Other important beliefs and barriers to screening varied by county type. This research can guide future cancer screening interventions in primary care settings in underserved communities.

Molecular basis for PICS-mediated piRNA biogenesis and cell division

By incorporating two mutually exclusive factors, PID-1 and TOST-1, C. elegans PICS complex plays important roles in piRNA biogenesis, chromosome segregation and cell division. We firstly map the interaction network between PICS subunits, then uncover the mechanisms underlying the interactions between PICS subunits by solving several complex structures, including those of TOFU-6/PICS-1, ERH-2/PICS-1, and ERH-2/TOST-1. Our biochemical experiment also demonstrates that PICS exists as an octamer consisting of two copies of each subunit. Combining structural analyses with mutagenesis experiments, we identify interfacial residues of PICS subunits that are critical for maintaining intact PICS complex in vitro. Furthermore, using genetics, cell biology and imaging experiments, we find that those mutants impairing the in vitro interaction network within PICS, also lead to dysfunction of PICS in vivo, including mislocalization of PICS, and reduced levels of piRNAs or aberrant chromosome segregation and cell division. Therefore, our work provides structural insights into understanding the PICS-mediated piRNA biogenesis and cell division.

Socioeconomic segregation between and within curriculum tracking

Previous studies have documented social segregation for single types of tracking, but little previous research has compared levels of segregation across different institutional tracking arrangements. This paper uses extensive administrative data of the Chilean educational system to estimate the magnitude and evolution of socioeconomic segregation between- and within-school curriculum tracking. Results indicate that the unequal distribution of students by socioeconomic status between tracks narrows when tracking takes place within schools, mainly in the presence of market incentives that lead schools to focus on particular student populations.

A novel evaluation method of aggregate distribution homogeneity for asphalt pavement based on the characteristics of texture structure

To realize the non-destructive detection of aggregate distribution homogeneity for asphalt pavement, the texture imaging device was developed to acquire the surface image of asphalt pavement. According to the distribution characteristics of texture structure, an improved segmentation algorithm for pavement texture image was proposed. A novel evaluation method of aggregate distribution homogeneity for asphalt pavement based on digital image processing (DIP) technique was discussed. The rutting specimens of asphalt mixture with standard segregation levels were simulated in laboratory, and the evaluation standard of aggregate distribution homogeneity was established. The results show that the improved threshold segmentation method combining rectangular partition and Otsu algorithm realizes the effective segmentation of texture structure from pavement image. The proposed index (D) for aggregate distribution homogeneity based on the quantity and location of texture structure has a good correlation with the texture depth, which can be used to evaluate the aggregate distribution homogeneity of asphalt pavement comprehensively. The evaluation standard of aggregate distribution homogeneity based on D value provides the reference to analyze the construction quality of asphalt pavement.

Are hierarchically formed embedded star clusters surviving gas expulsion depending on their initial conditions?

ABSTRACT We investigate the dissolution process of young embedded star clusters with different primordial mass segregation levels using fractal distributions by means of N-body simulations. We combine several star clusters in virial and subvirial global states with Plummer and uniform density profiles to mimic the gas. The star clusters have masses of Mstars = 500 M⊙ that follow an initial mass function where the stars have maximum distance from the centre of r = 1.5 pc. The clusters are placed in clouds that at the same radius have masses of Mcloud = 2000 M⊙, resulting in star formation efficiency of 0.2. We remove the background potential instantaneously at a very early phase, mimicking the most destructive scenario of gas expulsion. The evolution of the fraction of bound stellar mass is followed for a total of 16 Myr for simulations with stellar evolution and without. We compare our results with previous works using equal-mass particles where an analytical physical model was used to estimate the bound mass fraction after gas expulsion. We find that independent of the initial condition, the fraction of bound stellar mass can be well predicted just right after the gas expulsion but tends to be lower at later stages, as these systems evolve due to the stronger two-body interactions resulting from the inclusion of a realistic initial mass function. This discrepancy is independent of the primordial mass segregation level.

Metallurgical Gradients in Structural Materials: Potential and Challenges in Creating Artificial Segregations in Medium Manganese Steel via Roll‐Bonding

Segregation of alloying elements in metallic structural materials is often considered detrimental, as it results in local inhomogeneities of microstructure and properties. However, controlled levels of segregation may be utilized to adapt and improve the bulk property profile as a composite structure of metallurgical gradients. Roll‐bonding appears as an attractive technique to study and optimize the effects of segregations in a systematic manner. Here, the feasibility of creating artificial manganese segregation bands of ±5 wt%, in a medium manganese steel of the base composition Fe–0.1C–7Mn (wt%) in an alternating sequence, is demonstrated. After intercritical annealing at 650 °C for 6 h, the Fe–0.1C–7Mn layer consists of ≈17 vol% ultrafine‐grained austenite in a ferritic matrix. The Fe–0.1C–12Mn layer contains a higher amount of austenite, while the Fe–0.1C–2Mn layer shows a fully ferritic microstructure. The differences in mechanical behavior between the roll‐bonded and reference material emphasize the role of manganese segregations in controlling the local stability of austenite under different stress states. Moreover, the corrosion investigations in 0.1 m H2SO4 reveal the preferential dissolution of adjacent high manganese containing layers. Challenges regarding the roll‐bonding methodology for creating model materials, especially the role of layer interfaces, are outlined and discussed.

Hispanic Threat and Police Strength in U.S. Municipalities: The Moderating Influences of Nativity and Region

AbstractA key question of research on crime control is whether the level of police strength in cities primarily represents citizens’ collective interest in cutting crime, or whites’ interest in exerting control over minority populations in a racially divided society. Minority threat theories maintain that whites and police authorities seek to protect their interests by mobilizing their political power to enhance police strength in cities with relatively large minority populations. Research testing this hypothesis examines the relationships of percent black and percent Hispanic to the strength of police departments. Studies of blacks support minority threat theories, but the limited research on Hispanics does not. We extend research on Hispanics by incorporating nativity and region into an analysis of cities of 100,000 or more population in 2010. Noteworthy findings include complex interactions involving those predictors. Percent native-born Hispanic has a stronger negative relationship with police strength at higher levels of Hispanic-white residential segregation, but only in southwestern cities. Percent black is associated with increased police strength at higher levels of black-white segregation, but only in non-southwestern cities. These findings indicate that nativity, segregation, and regional context may jointly shape the mobilization of coercive crime control, sometimes in unexpected ways.

Segregation, Caste and Cash: Segrenomics in Detroit

Though in other countries caste is generally understood to name social stratification based on ethnic and/or religious affiliation, in the United States, racial and economic segregation in housing and education are the factors that trap one to the lower rungs of the social system in that nation. Significantly, these caste making levels of segregation are “cash making” for wealthy business concerns. In my earlier work, I have referred to this profit from segregation as, “segrenomics.” In this piece, I offer an example of the mechanics of these relationships relative to segregated schools, caste, and cash making in the city of Detroit, Michigan.

Immigration, segregation and neighborhood change in Berlin

Even though the issue of immigrant-native segregation in Europe has been continuously researched for the last thirty years the attempts to illuminate the changing levels of ethnic segregation in the European city in the 21st century leave the case of Germany largely unexplored. The aim of this paper is to shed light on the evolving patterns of segregation and neighborhood change in Berlin in the 2010s (2007-2016). The traditional indices of segregation and the neighborhood typology are used to assess changes in the levels of segregation and patterns of residential intermixing, respectively. We also employ the sequence analysis method to investigate full trajectories of neighborhood change, and a regression tree for the sequences of neighborhood transitions is used to evaluate the effect of urban structure on ethnic neighborhood change. Despite considerable immigration, in total, immigrant-native segregation in Berlin declined over the last decade. Three decades after the fall of the Berlin Wall, along with the selective spatial effects of international immigration, the spatial division of Berlin into the inner- and outer-city appears to be a decisive factor in the evolution of the local patterns of immigrant-native residential intermixing.

Discovering income-economic segregation patterns: A residential-mobility embedding approach

As most studies of segregation rely on the evenness dimension, this current study proposes a graph embedding approach to explore the usefulness of employing the isolation-exposure dimension to evaluate income segregation. While most segregation studies analyzed the static distribution of population subgroups, current study attempts to classify neighborhoods based on house value as a proxy of income, residents' exposure to people of different income levels as constrained by their mobility patterns, and amenities available in the neighborhood. This study exploits the graph embedding method to classify neighborhoods by combining their various attributes, static population distribution and mobility data provided by smart cards to analyze income segregation in Shenzhen, China. Results identify four types of communities with different economic statuses, mobility patterns, and amenity characteristics. They provide rich descriptions about the connections between income segregation patterns, population dynamics, and neighborhood characteristics. The study found that the more segregated communities, which are composed of the poorest and richest groups, are mostly in the peripheral regions of the city while the inner city has lower levels of segregation, mainly due to differentials in transit accessibility. The study demonstrates the great potential of the proposed method to incorporate multiple aspects to evaluate segregation.

CHOCOLATE CITY, VANILLA SUBURBS REVISITED

AbstractDespite the long history of racial hostility, African Americans after 1990 began moving from the city of Detroit to the surrounding suburbs in large numbers. After World War II, metropolitan Detroit ranked with Chicago, Cleveland, and Milwaukee for having the highest levels of racial residential segregation in the United States. Detroit’s suburbs apparently led the country in their strident opposition to integration. Today, segregation scores are moderate to low for Detroit’s entire suburban ring and for the larger suburbs. Suburban public schools are not highly segregated by race. This essay describes how this change has occurred and seeks to explain why there is a trend toward residential integration in the nation’s quintessential American Apartheid metropolis.

Coupled Antigen and BLIMP1 Asymmetric Division With a Large Segregation Between Daughter Cells Recapitulates the Temporal Transition From Memory B Cells to Plasma Cells and a DZ-to-LZ Ratio in the Germinal Center.

Memory B cells and antibody-secreting plasma cells are generated within germinal centers during affinity maturation in which B-cell proliferation, selection, differentiation, and self-renewal play important roles. The mechanisms behind memory B cell and plasma cell differentiation in germinal centers are not well understood. However, it has been suggested that cell fate is (partially) determined by asymmetric cell division, which involves the unequal distribution of cellular components to both daughter cells. To investigate what level and/or probability of asymmetric segregation of several fate determinant molecules, such as the antigen and transcription factors (BCL6, IRF4, and BLIMP1) recapitulates the temporal switch and DZ-to-LZ ratio in the germinal center, we implemented a multiscale model that combines a core gene regulatory network for plasma cell differentiation with a model describing the cellular interactions and dynamics in the germinal center. Our simulations show that BLIMP1 driven plasma cell differentiation together with coupled asymmetric division of antigen and BLIMP1 with a large segregation between the daughter cells results in a germinal center DZ-to-LZ ratio and a temporal switch from memory B cells to plasma cells that have been observed in experiments.

Socio-economic segregation in European cities. A comparative study of Brussels, Copenhagen, Amsterdam, Oslo and Stockholm

ABSTRACT The purpose of this study is to compare socioeconomic segregation patterns and levels in Brussels, Copenhagen, Amsterdam, Oslo, and Stockholm with uniform measurements. Previous research has been hampered by conceptual and methodological shortcomings. We use harmonized datasets containing geocoded indicators based on a nearest-neighbors approach. Our analyses offer an unprecedented comparison of patterns and levels of socio-spatial inequalities in European capitals at multiple scales. Using maps, segregation indices and percentile plots, we find that for all cities, the segregation of the rich is much stronger than the segregation of the poor. Macro-scale poverty segregation is most prominent in Stockholm and Brussels, and quite low in Amsterdam, while macro-scale affluence segregation is most pronounced in Oslo. At micro-scales, Brussels and Stockholm stand out with very high local poverty concentrations, indicating high levels of polarization. We interpret differences in the light of spatial inequalities, welfare regimes, housing systems, migration and area-based interventions.

The Past, Present, and Future of Brown’s Mandate: A View from North Carolina

The unanimous 1954 Brown v. Board of Education opinion is one of the most consequential legal decisions of the 20th century. Even though it concerned government sanctioned racial segregation of public schools, many legal scholars, policy makers, and citizens see Brown’s impact going well beyond ordering the dismantling of de jure segregated public schools and instituting desegregated ones that would provide equitable high quality public education to all students irrespective of their race. Brown’s mandate overturned the notorious Plessy decision sanctioning legal segregation and exposed the fiction that separate could be equal in any institution or sphere of public life. But, progress toward Brown’s literal and figurative mandate has been halting and, at best, uneven. This article considers the question of whether the nation will achieve Brown’s mandate by its 100th anniversary in 2054. The authors reflect upon the relevant history of progress in Brown’s implementation and the current retrenchments on those gains that have returned this nation’s schools, in some districts, to pre- Brown levels of segregation. Using the state of North Carolina as a strategic case study, they speculate about the sets of social forces that may either discourage or encourage realization of Brown’ s mandate going forward. In doing so, they note population changes, national and local political factors, and other events that will either make it more or less likely that Brown’s mandate will be realized by 2054.