High Segregation Research Articles

Structural covariance networks in anorexia nervosa (AN): A multimodal graph theoretical analysis

IntroductionThe possibility of evaluating cortical morphological and structural features on the basis of their covariance patterns is becoming increasingly important in clinical neuroscience, because their organizational principles reveal an inter-regional structural dependence which derive from a complex mixture of developmental, genetic and environmental factors.ObjectivesIn this study, we describe cortical network organization in anorexia nervosa using a MRI morpho-structural covariance analysis based on cortical thickness, gyrification and fractal dimension.AimAim of the research is to evaluate any alterations in structural network properties measured with graph theory from multi-modal imaging data in AN.MethodsThirty-eight patients with acute AN, 38 healthy controls and 20 patients in full remission from AN underwent MRI scanning. Surface extraction was completed using FreeSurfer package. Graph analysis was performed using graph analysis toolbox.ResultsIn acute patients, the covariance analysis among cortical thickness values showed a more segregated pattern and a reduction of global integration indexes. In the recovered patients group, we noticed a similar global trend without statistically significant differences for any single parameter. According to gyrification indexes, the covariance network showed a trend towards high segregation both in acute and recovered patients. We did not observe any significant difference in the covariance networks in the analysis of fractal dimension.ConclusionsThe presence of increased segregation properties in cortical covariance networks in AN may be determined by a retardation of neurodevelopmental trajectories or by an energy saving adaptive response. The differences between the analyzed parameters likely depend on their different morpho-functional meanings.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Gridlock: Ethnic Diversity in Government and the Provision of Public Goods

How does ethnic diversity in government impact public good provision? We construct a novel dataset linking the ethnicity of California city council candidates to election outcomes and expenditure decisions. Using a regression discontinuity approach, we find that increased diversity on the council leads to less spending on public goods. This is especially true in cities with high segregation and economic inequality. Those serving on councils that experience an increase in diversity also receive fewer votes when they run for reelection. These results point towards disagreement within the council generating lower spending. (JEL D72, H41, H70, J15, R23, R51)

ZnO decorated germanium nanoparticles as anode materials in Li-ion batteries

Germanium exhibits high charge capacity and high lithium diffusivity, both are the key requirements for electrode materials in high performance lithium ion batteries (LIBs). However, high volume expansion and segregation from the electrode during charge–discharge cycling have limited use of germanium in LIBs. Here, we demonstrate that ZnO decorated Ge nanoparticles (Ge@ZnO NPs) can overcome these limitations of Ge as an LIB anode material. We produced Ge NPs at high rates by laser pyrolysis of GeH4, then coated them with solution phase synthesized ZnO NPs. Half-cell tests revealed dramatically enhanced cycling stability and higher rate capability of Ge@ZnO NPs compared to Ge NPs. Enhancements arise from the core–shell structure of Ge@ZnO NPs as well as production of metallic Zn from the ZnO layer. These findings not only demonstrate a new surface treatment for Ge NPs, but also provide a new opportunity for development of high-rate LIBs.

Segregation for fertility and meiotic stability in novel Brassica allohexaploids.

Allohexaploid Brassica populations reveal ongoing segregation for fertility, while genotype influences fertility and meiotic stability. Creation of a new Brassica allohexaploid species is of interest for the development of a crop type with increased heterosis and adaptability. At present, no naturally occurring, meiotically stable Brassica allohexaploid exists, with little data available on chromosome behaviour and meiotic control in allohexaploid germplasm. In this study, 100 plants from the cross B. carinata × B. rapa (A2 allohexaploid population) and 69 plants from the cross (B. napus × B. carinata) × B. juncea (H2 allohexaploid population) were assessed for fertility and meiotic behaviour. Estimated pollen viability, self-pollinated seed set, number of seeds on the main shoot, number of pods on the main shoot, seeds per ten pods and plant height were measured for both the A2 and H2 populations and for a set of reference control cultivars. The H2 population had high segregation for pollen viability and meiotic stability, while the A2 population was characterised by low pollen fertility and a high level of chromosome loss. Both populations were taller, but had lower average fertility trait values than the control cultivar samples. The study also characterises fertility and meiotic chromosome behaviour in genotypes and progeny sets in heterozygous allotetraploid Brassica derived lines, and indicates that genotypes of the parents and H1 hybrids are affecting chromosome pairing and fertility phenotypes in the H2 population. The identification and characterisation of factors influencing stability in novel allohexaploid Brassica populations will assist in the development of this as a new crop species for food and agricultural benefit.

Disparities in kidney transplantation across the United States: Does residential segregation play a role?

BackgroundAlthough residential segregation has been implicated in various negative health outcomes, its association with kidney transplantation has not been examined. MethodsAge- and sex-standardized kidney transplantation rates were calculated from the Scientific Registry of Transplant Recipients, 2000–2013. Population characteristics including segregation indices were derived from the 2010 U.S. Census data and the U.S. Renal Data System. Separate multivariable Poisson regression models were constructed to identify factors independently associated with kidney transplantation among Blacks and Whites. ResultsMedian age- and sex-standardized kidney transplantation rates were 114 per 100,000 for Blacks and 38 per 100,000 for Whites. 16.1% of the U.S. population lived in counties with high segregation. There was no difference in the kidney transplantation rates across the levels of segregation among Blacks and Whites. ConclusionFactors other than residential segregation may play roles in kidney transplantation disparities. Continued efforts to identify these factors may be beneficial in reducing transplantation disparities across the U.S. SummaryUsing the Scientific Registry of Transplant Recipients and U.S. census data, we aimed to determine whether residential segregation was associated with kidney transplantation rates. We found that there was no association between residential segregation and kidney transplantation rates.

Effect of sequence dispersity on morphology of tapered diblock copolymers from molecular dynamics simulations.

Tapered diblock copolymers are similar to typical AB diblock copolymers but have an added transition region between the two blocks which changes gradually in composition from pure A to pure B. This tapered region can be varied from 0% (true diblock) to 100% (gradient copolymer) of the polymer length, and this allows some control over the microphase separated domain spacing and other material properties. We perform molecular dynamics simulations of linearly tapered block copolymers with tapers of various lengths, initialized from fluids density functional theory predictions. To investigate the effect of sequence dispersity, we compare systems composed of identical polymers, whose taper has a fixed sequence that most closely approximates a linear gradient, with sequentially disperse polymers, whose sequences are created statistically to yield the appropriate ensemble average linear gradient. Especially at high segregation strength, we find clear differences in polymer conformations and microstructures between these systems. Importantly, the statistical polymers are able to find more favorable conformations given their sequence, for instance, a statistical polymer with a larger fraction of A than the median will tend towards the A lamellae. The conformations of the statistically different polymers can thus be less stretched, and these systems have higher overall density. Consequently, the lamellae formed by statistical polymers have smaller domain spacing with sharper interfaces.

Structural, electrical, magnetic and magnetoelectric properties of (1−y) [Ba0.6−xCaxSr0.4Zr0.25Ti0.75O3] + (y) [(Li0.5Fe0.5)0.4Ni0.18Cu0.12Zn0.3Fe2O4] composites

Magnetoelectric composites having the nominal composition of (1-y) [Ba0.6-xCaxSr0.4Zr0.25Ti0.75O3] (BCSZTO) + (y) [(Li0.5Fe0.5)0.4Ni0.18Cu0.12Zn0.3Fe2O4] (LNCZFO) (x = 0.0, 0.1, 0.2 and y = 0.2, 0.4, 0.6, and 0.8) were synthesized by the solid state reaction method and sintered at 1200 °C for 3 h. The X-ray diffraction analysis confirms the coexistence of tetragonal perovskite BCSZTO and spinel LNCZFO phases with Ba6T17O46 as impurity phase. Microstructural and quantitative elemental of the samples were carried out by Field Emission Scanning Electron Microscopy equipped with Energy Dispersive X-ray Spectroscopy. Low frequency dielectric dispersion is attributed due to Maxwell-Wagner interfacial polarization arising from the interface of the two phases in agreement with Koop's phenomenological theory. Frequency independent behavior of dielectric constant at higher frequencies is attributed due to the inability of electric dipoles to follow the first variation of the alternating applied electric field. The dielectric constant decreases with the increasing Ca2+ concentration which is attributed due to the increased resistivity. Maxima in dielectric loss (tanδ) are appeared when the hopping frequency of electrons between different ionic sites becomes nearly equal to the frequency of the applied field. AC conductivity of the composites follows Jonscher's universal power law and the conduction mechanism is attributed due to small polaron hopping. AC conductivity increases with the increase of Ca2+ concentration. The composite materials are found to exhibit excellent frequency dependence and increases with the ferrite concentration. The permeability decreases with the increase of Ca2+ concentration which is attributed to the smaller grain size and increased magneto crystalline anisotropy. The quality factor increases with the Ca2+ ions substitution on account of the high resistive boundary segregation. The magnitude of magnetoelectric (ME) voltage coefficient increase linearly with the increase of the applied filed may be attributed to the nominally linear gradient of magnetostriction with respect to magnetic field. The magnetoelectric coefficient of the composites increases gradually as the increase in the ferrite content which is attributed due to the increase of the mechanical deformation in the magnetostrictive phase. An optimal magnetoelectric voltage coefficient of ∼1.16 V cm−1 Oe−1 is obtained for x = 80 wt% (C-series composites) at room temperature.

Using residential segregation to predict colorectal cancer stage at diagnosis: two different approaches

PurposeStudies have found a variety of evidence regarding the association between residential segregation measures and health outcomes in the United States. Some have focused on any individuals living in residentially segregated places, whereas others have examined whether persons of specific races or ethnicities living in places with high segregation of their own race or ethnicity have differential outcomes. This article compares and contrasts these two approaches in the study of predictors of late-stage colorectal cancer (CRC) diagnoses in a cross-national study. We argue that it is very important when interpreting results from studies like this to carefully consider the geographic scope of the analysis, which can significantly change the context and meaning of the results. MethodsWe use US Cancer Statistics Registry data from 40 states to identify late-stage diagnoses among over 500,000 CRC cases diagnosed during 2004–2009. We pool data over the states and estimate a multilevel model with person, county, and state levels and a random intercepts specification to ensure robust effect estimates. The isolation index of residential segregation is defined for racial and ethnic groups at the county level using Census 2000 data. The association between isolation indices and late-stage CRC diagnosis was measured by (1) anyone living in minority-segregated areas (place-centered approach) and by (2) individuals living in areas segregated by one's own racial or ethnic peers (person-centered approach). ResultsFindings from the place-centered approach suggest that living in a highly segregated African American community is associated with lower likelihood of late-stage CRC diagnosis, whereas the opposite is true for people living in highly segregated Asian communities, and living in highly segregated Hispanic communities has no significant association. Using the person-centered approach, we find that living in places segregated by one's racial or ethnic peers is associated with lower likelihood of late-stage CRC diagnosis. ConclusionsIn a model that covers a large geographic area across the nation, the place-centered approach is most likely picking up geographic disparities that may be deepened by targeted interventions in minority communities. By contrast, the person-centered approach provides a national average estimate suggesting that residential isolation may confer community cohesion or support that is associated with better CRC prevention.

Effect of Electromagnetic Field on the Macrosegregation Behaviour of Al-Cu Alloy Ingot Prepared with Direct-Chill Casting Process

A low frequency electromagnetic field was introduced into the direct chill (DC) casting process and the ingots of Al-Cu alloy were prepared to study the macrosegregation behaviour of the ingots under the influence of the electromagnetic field. The experimental results showed that there is an obvious positive segregation near to the surface and a negative segregation in the centre area of the ingot. Cu shows the highest segregation tendency among the main elements of Cu, Mg and Mn. Grain refiner element Ti shows a segregation trend opposite to that of Cu. With the application of electromagnetic field, the negative centreline segregation in the centre area of the ingot was evidently reduced although it didn’t show significant effect on the segregation near to the ingot surface. A significant grain refinement was also achieved with the application of electromagnetic field. The mechanism of the reduction of macrosegregation with electromagnetic field was also analyzed in the present work.

Neighborhood Socioeconomic Disadvantage; Neighborhood Racial Composition; and Hypertension Stage, Awareness, and Treatment Among Hypertensive Black Men in New York City: Does Nativity Matter?

Neighborhood-level poverty and racial composition may contribute to racial disparities in hypertension outcomes. Little is known about how the effects of neighborhood social environments may differ by nativity status among diverse urban Black adults. We aimed to characterize the influence of neighborhood-level socio-demographic factors on hypertension outcomes among US- and foreign-born Black men with uncontrolled blood pressure. We conducted a cross-sectional analysis of baseline data from two large community-based trials of hypertensive Black men aged 50 and over linked with census tract data from the 2012 American Community Survey 5-year estimates. We defined census tracts with high racial segregation as those where 60% or more self-identified as Black and high-poverty census tracts as those where 20% or more lived below the poverty line. Multivariable general estimating equation models were used to measure associations between neighborhood characteristics and stage of hypertension, hypertension awareness, and treatment to yield adjusted prevalence ratios (aPR). Models were run separately for US- and foreign-born Black men. Over 64% of the 1139 participants lived in a census tract with a high percentage of Black residents and over 71% lived in high-poverty census tracts. Foreign-born Black men living in neighborhoods with a high concentration of Black residents were less likely to be treated for their high blood pressure (aPR 0.44, 95% CI 0.22-0.88), but this result did not hold for US-born Black men. There were no significant associations between neighborhood poverty and hypertension outcomes. Neighborhood context may impact treatment for hypertension, one of the most important factors in hypertension control and decreasing hypertension-related mortality, particularly among foreign-born Black men.

The Relationship of Neighborhood Socioeconomic Differences and Racial Residential Segregation to Childhood Blood Lead Levels in Metropolitan Detroit.

This study uses a new approach to assess the impact of different neighborhood characteristics on blood lead levels (BLLs) of black versus white children in metropolitan Detroit. Data were obtained from the Michigan Department of Community Health and the US Bureau of the Census American Community Survey. The Modified Darden-Kamel Composite Socioeconomic Index, bivariate regression, and the index of dissimilarity were used to compute neighborhood BLL unevenness by neighborhood characteristics. Neighborhoods with lower socioeconomic characteristics and high racial residential segregation predicted higher average childhood BLLs. This reveals a social spatial structure that will aid researchers/policymakers in better understanding disparities in childhood BLLs.

Beginning of a new age: How did freshwater gastropods respond to the Quaternary climate change in Europe?

Abstract The well documented fossil record of European Quaternary freshwater gastropods offers a unique resource for continental-scale biogeographical analyses. Here, we assembled a dataset including 338 freshwater gastropod taxa from 1058 localities across Europe, which we used to explore how freshwater gastropod communities varied in space and time across six distinct time intervals of the Quaternary, i.e. Gelasian, Calabrian, Middle Pleistocene, Last Interglacial, Last Glacial and Holocene. We took into consideration both species richness and qualitative structural patterns, comparing turnover rates between time intervals and examining variations in community nestedness-segregation patterns. Species richness differed significantly between time intervals. The Early Pleistocene showed the highest diversity, likely because of the contribution of long-lived aquatic systems like the lakes Bresse and Tiberino that promoted speciation and endemism. The rich Middle to Late Pleistocene and Holocene assemblages were mostly linked to fluvial and/or lacustrine systems with short temporal durations. We identified a major turnover event at the Plio-Pleistocene boundary, related to the demise of long-lived lakes and of their rich, endemic faunas at the end of the Pliocene. In the subsequent intervals, little or no turnover was observed. We also observed a pattern of high segregation in Early Pleistocene communities, associated with the abundance of endemic species with small distribution ranges, and reflecting the provincial character of the aquatic freshwater systems at that time. This structured pattern disintegrated gradually towards the Middle Pleistocene and remained unstructured up to present. In particular, spatial patterns of community nestedness-segregation in the Last Interglacial and Holocene suggest a random recolonization of freshwater habitats mostly by generalist species following deglaciation.

Globally Efficient Brain Organization and Treatment Response in Psychosis: A Connectomic Study of Gyrification.

Background:Converging evidence suggests that patients with first-episode psychosis who show a poor treatment response may have a higher degree of neurodevelopmental abnormalities than good Responders. Characterizing the disturbances in the relationship among brain regions (covariance) can provide more information on neurodevelopmental integrity than searching for localized changes in the brain. Graph-based connectomic approach can measure structural covariance thus providing information on the maturational processes. We quantified the structural covariance of cortical folding using graph theory in first-episode psychosis, to investigate if this systems-level approach would improve our understanding of the biological determinants of outcome in psychosis.Methods:Magnetic Resonance Imaging data were acquired in 80 first-episode psychosis patients and 46 healthy controls. Response to treatment was assessed after 12 weeks of naturalistic follow-up. Gyrification-based connectomes were constructed to study the maturational organization of cortical folding.Results:Nonresponders showed a reduction in the distributed relationship among brain regions (high segregation, poor integration) when compared to Responders and controls, indicating a higher burden of aberrant neurodevelopment. They also showed reduced centrality of key regions (left insula and anterior cingulate cortex) indicating a marked reconfiguration of gyrification. Nonresponders showed a vulnerable pattern of covariance that disintegrated when simulated lesions removed high-degree hubs, indicating an abnormal dependence on highly central hub regions in Nonresponders.Conclusions:These findings suggest that a perturbed maturational relationship among brain regions underlies poor treatment response in first-episode psychosis. The information obtained from gyrification-based connectomes can be harnessed for prospectively predicting treatment response and prognosis in psychosis.

The Effects of Residential Segregation and Neighborhood Characteristics on Surgery and Survival in Patients with Early-Stage Non-Small Cell Lung Cancer.

Although the negative effects of lower socioeconomic status on non-small cell lung cancer (NSCLC) treatment and survival have been widely studied, the impact of residential segregation on prognosis and the receipt of treatment has yet to be determined. This is a retrospective, cohort study of NSCLC patients in Georgia (2000-2009; n = 8,322) using data from the Georgia Comprehensive Cancer Registry. The effects of segregation, economic deprivation, and combined segregation/deprivation on the odds of receiving surgery were examined in separate multilevel models. To determine the association for the exposures of interest on the risk of death for different racial groups, separate multilevel survival models were conducted for black and white patients. Living in areas with the highest [AOR = 0.35, 95% confidence interval (CI), 0.19-0.64] and second highest (AOR = 0.37, 95% CI, 0.20-0.68) levels of segregation was associated with decreased odds of receipt of surgery. Black patients living in areas with high residential segregation and high economic deprivation were 31% (95% CI, 1.04-1.66) more likely to die, even after surgery was controlled for. For white patients, economic deprivation was associated with decreased odds of surgery but not survival. Segregation had no effect. Our findings suggest how black and white individuals experience segregation and area-level poverty is likely different leading to differences in adverse health outcomes. Identifying neighborhood characteristics impacting health outcomes within different racial groups could help reduce health disparities across racial groups by implementing targeted policies and interventions. Cancer Epidemiol Biomarkers Prev; 25(5); 750-8. ©2016 AACR.

Simulation and comparative study of tunneling field effect transistors with dopant-segregated Schottky source/drain

Dopant-segregated Schottky source/drain tunneling field effect transistors (STFET) are investigated in this paper. The working mechanisms of STFET and the influence of device parameters are studied with Synopsys Sentaurus. Schottky source/drain MOSFETs possess several advantages over conventional MOSFETs, and dopant segregation can be feasibly achieved within current silicidation process. With dopant segregation, highly doped regions can be obtained after silicidation, which is necessary for band-to-band tunneling. With proper parameter setting, STFET can achieve comparable performance as TFET. High segregation doping for STFET is required to increase band-to-band tunneling probability and suppress bipolar behaviors. Increasing the electron barrier height at source side helps to provide larger drive current and higher on/off ratio. It is also found that STFET’s on-state performance is irrelevant to the segregation length when the segregation length is larger than a certain value. Furthermore, STFET is also insensitive to the Schottky barrier at drain side when the Schottky barrier at source side is fixed, which would relax the requirement for source/drain fabrication.

High-Throughput Sequencing Shows High Fungal Diversity and Community Segregation in the Rhizospheres of Container-Grown Conifer Seedlings

Forest nurseries in Sweden produce ca. 360 million seedlings of Pinus sylvestris L. and Picea abies (L.) Karst. annually. Fungi represent the largest microbial component in rhizospheres and may significantly affect health and, consequently, quality of the seedlings. The aim of this study was to assess fungi focusing on pathogens in roots and the sphagnum peat growth substrate of healthy-looking P. sylvestris and P. abies seedlings from nine forest nurseries situated in northern, central and southern regions of Sweden. We hypothesized that nursery stock and the growth substrate can provide a venue for dissemination of fungal diseases. In each nursery and for each tree species, 100 seedlings with the growth substrate were collected during the dormant period. DNA was isolated from parts of root systems and from samples of the growth substrate, amplified using internal transcribed spacer of rDNA as a marker and 454-sequenced. Clustering at 98.5% similarity of 169,844 high-quality sequences resulted in 619 non-singleton fungal taxa. Although results showed that management practices in forest nurseries generally give a healthy stock, latent establishment of pathogenic fungi in both roots and the growth substrate supported the hypothesis. Furthermore, seedling roots and the growth substrate were inhabited by distinct communities of fungi, and lifestyles of these fungi largely determined community segregation into particular ecological niche.

Influence of Casting Velocity on Mechanical Properties and Macro-Structure of Tin Bronzes

Continuous casting is the most productive method of casting. Manufacturers often tend to increase casting velocity without taking into account the fact that it can cause latent defects within the casting and accordingly lead to a deterioration of the mechanical properties of product. The casting process of tin bronzes encumbers high shrinkage and high segregation in the cross section of the castings. The research was performed on three types of tin bronze alloys CuSn12-C, CuSn5Zn5Pb2-C, and CuSn7Zn3Pb7-C (EN 1982:2008). Influence of casting velocity on mechanical properties and macrostructure was studied and optimal velocity parameters were given. The following study revealed a significant effect of the velocity of continuous casting on the mechanical properties of tin bronze, which was also reflected in the macrostructure of the selected samples. Based on the results of the study the recommendations about the optimal casting parameters to increase a quality of end-product were given. The recommendations were later implemented in the manufacturing confirming the value of this study.

Immigration, Poverty, and Socioeconomic Inequality, edited by David Card and Steven Raphael. 2013. Series: National Poverty Center Series on Poverty and Public Policy. New York: Russell Sage Foundation. 469 + xiv. ISBN: 978-0-87154-498-8, $55.

Immigration, Poverty, and Socioeconomic Inequality, edited by David Card and Steven Raphael. 2013. Series: National Poverty Center Series on Poverty and Public Policy. New York: Russell Sage Foundation. 469 + xiv. ISBN: 978-0-87154-498-8, $55.

On Being a Scientist, Private Lives and their Harmonization

Women in the high academic positions represent an elite group of women, whose experience has not been described separately in the Czech sociological context yet. The university environment is historically masculine denoted area, which women entered with many difficulties. Despite of opening of this academic area to women, we still see the high vertical segregation at the high academic positions. The interviews were ment to show how women reflect their own experience. The article deals with the work-lifebalance. All of the respondents have developped a very strong tie to their profession, which helps them overcome barriers in their professional growth, that are caused by problems arising from the reconciliation of family and work responsibilities. Their view of own and other women position is rather optimistic, with limited gender sensitivity.

Does Racial Segregation Make Community-Based Organizations More Territorial? Evidence from Newark, Nj, and Jersey City, Nj

ABSTRACT:This article contributes to research on urban nonprofit community-based organizations (CBOs) by exploring how high racial/ethnic segregation within a city creates a context wherein CBOs become territorial. CBOs have long been recognized for their role in providing services to the urban disadvantaged. Organizations with a strong sense of territoriality typically have robust ties with their base neighborhoods, very thorough in supporting residents in those places. After interviewing 40 CBO staffers in Newark, NJ, and Jersey City, NJ, I identify three paths through which the condition of high segregation in a city leads to territorial CBOs: (1) demographically, organizations become associated with bounded, racially segregated neighborhoods; (2) politically, racially motivated political contention compels organizations to identify more closely with their base neighborhoods; and (3) financially, disadvantage concentrated along racial/ethnic lines contributes to concentrated funding efforts for the city’s nonprofit sector, which in turn places greater scrutiny on where organizations situate.