Elevated Depressive Symptoms In A Community Sample Of African-Americans And Whites

This study examined demographic and psychosocial correlates of elevated depressive symptoms among African-Americans and Whites from comparable socioeconomic and neighborhood backgrounds. 851 African-Americans and 597 Whites from adjacent census tracts were interviewed using previously validated indicators of depressive symptoms, social support, religious practices and various demographic characteristics. More Whites than African-Americans reported elevated depressive symptoms and the groups also differed on several demographic variables and psychosocial variables. Employment, marital status and age were salient demographic covariates for African Americans, while income was for Whites. For both groups, social support and church attendance were inversely associated with depressive symptoms. Prayer was positively associated with depressive symptoms. Future research should explore within racial/ethnic group variations in depressive symptoms. Insights also are needed into possible changes over time in the relationship between religious variables and depressive symptoms, and how social support limits depressive symptoms in diverse populations

Characterization of Starch Structures of 17 Maize Endosperm Mutant Genotypes with Oh43 Inbred Line Background.

The characteristics of starches from 17 endosperm mutant genotypes in a common Oh43 inbred background were examined by gel-permeation chromatography (GPC), iodine affinity (IA), and scanning electron microscopy (SEM). The chain-length distributions of amylopectins were determined by an enzymatic- chromatographic method. Each genotype exhibited distinctive GPC elution patterns of its native and isoamylase-debranched starches and distinctivemorphology as noted by SEM. The amylose-extender (ae), dull-1 (du1), and sugary-1 (su1) genes were associated with increased amounts of amylose and intermediate fractions compared with normal starch. The waxy (wx) gene was epistatic to other genes relative to the accumulation of amylopectin, which was consistent with work done elsewhere. The discrepancy in amylose percentage determined by GPC and IA in some genotypes may have resulted from the presence of a large amount of intermediate materials in those genotypes, which could not always be distinguished from amylose by the IA method. For example, in ae starch, most of the intermediate materials were measured as amylose by the IA procedure, whereas in du1, ae brittle-1 (bt1), and ae du1 starches, most of the intermediate materials were exclded from IA measurements. The intermediate fractions from each genotype in the GPC elution profiles also differed from each other, suggesting differences in molecular weight and/or branching. The proportions of long B chains and the average chain length of amylopectins were increased when the ae gene was present. In contrast, the du1 gene decreased the proportions of the long B chains of amylopectins. The mutants containing he ae gene showed low degrees of branching in amylopectin; mutants containing the du1 and/or su1 genes hd high degrees of branching. Genetic background played a major role in determining the fine structure of starch components. The effects of interactions between recessive mutant genes on the structures and morphology of different starch genotypes were evident

Amylopectin and Intermediate Materials in Starches from Mutant Genotypes of the Oh43 Inbred Line.

Amylopectin (AP) and intermediate materials (IM) from five endosperm mutant genotypes in a common Oh43 inbred line were isolated and examined by gel-permeation chromatography, iodine affinity, blue value (BV), and viscosity. The chain-length distributions of AP and IM were determined using an enzymatic- chromatographic method. The degrees of branching in AP and IM decreased when the amylose-extender (ae) gene was present. The dull-1 (du1) gene produced AP and IM with the highest degrees of branching among the samples. The ae starch had a significantly (P less than 0.01) longer peak average chain length (CL) of the long-B chains in the IM fraction (177 glucose units) than did the AP faction (73 glucose units) or the other starches (37-56 glucose units). The higher iodine affinity in ae starch of the IM (6.1) compared with that of the AP (2.8) supported the idea that the IM had a longer CL than did the AP. There were no significant differences in the peak CL of A or B chains in AP and IM fractions of brittle-1 (bt1), du1, ae bt1, and ae du1 starches. The IM of ae and ae du1 starches had higher BV than did the AP fractions; however, the IM of du1 and ae bt1 had lower BV than did the AP fractions. The limiting viscosity number and gel- permeation chromatography results indicated that the AP and IM fractions of bt1 and du1 starches possessed more branching and larger hydrodynamic volume properties than those of the ae, ae bt1, and ae du1 starches. The present study demonstrated that genetic background affects the CL of starch branches, degree of branching, and iodine binding properties of starches

Attention Effects in a High-Frequency World

How does limited attention affect stock prices in today’s computer-driven financial markets? We study this issue by re-examining the effects of limited attention using a dataset that separately identifies trades made by high-frequency traders (HFTs, or computers) versus those made by non-high-frequency traders (human decision-makers). We employ a set of six attention proxies to identify earnings announcements with low investor attention: announcements made on Fridays and on days with multiple earnings announcements, and announcements with slow analyst forecast adjustments, high news distraction, low EDGAR download volume, and low Google search volume. Across multiple attention proxies, we find that HFT trading improves the responsiveness of prices by increasing the short-horizon price response and reducing the long-term price drift following earnings surprises, diminishing the inefficiencies previously observed around low-attention announcements by 69% to 100%. We find that the price efficiency improvements are more closely tied to HFT liquidity demand than supply, suggesting that HFTs improve efficiency by processing and trading on the information in low-attention announcements

Effects of receptor dimerization on the interaction between the class I major histocompatibility complex-related Fc receptor and IgG

The neonatal Fc receptor (FcRn) transports maternal IgG from ingested milk in the gut to the bloodstream of newborn mammals. An FcRn dimer was observed in crystals of the receptor alone and of an FcRn-Fc complex, but its biological relevance was unknown. Here we use surface plasmon resonance-based biosensor assays to assess the role of FcRn dimerization in IgG binding. We find high-affinity IgG binding when FcRn is immobilized on a biosensor chip in an orientation facilitating dimerization but not when its orientation disrupts dimerization. This result supports a model in which IgG-induced dimerization of FcRn is relevant for signaling the cell to initiate endocytosis of the IgG-FcRn complex

Associations of Adiponectin with Adiposity, Insulin Sensitivity, and Diet in Young, Healthy, Mexican Americans and Non-Latino White Adults.

Low circulating adiponectin levels may contribute to higher diabetes risk among Mexican Americans (MA) compared to non-Latino whites (NLW). Our objective was to determine if among young healthy adult MAs have lower adiponectin than NLWs, independent of differences in adiposity. In addition, we explored associations between adiponectin and diet. This was an observational, cross-sectional study of healthy MA and NLW adults living in Colorado (U.S.A.). We measured plasma total adiponectin, adiposity (BMI, and visceral adipose tissue), insulin sensitivity (IVGTT), and self-reported dietary intake in 43 MA and NLW adults. Mean adiponectin levels were 40% lower among MA than NLW (5.8 ± 3.3 vs. 10.7 ± 4.2 µg/mL, p = 0.0003), and this difference persisted after controlling for age, sex, BMI, and visceral adiposity. Lower adiponectin in MA was associated with lower insulin sensitivity (R² = 0.42, p < 0.01). Lower adiponectin was also associated with higher dietary glycemic index, lower intake of vegetables, higher intake of trans fat, and higher intake of grains. Our findings confirm that ethnic differences in adiponectin reflect differences in insulin sensitivity, but suggest that these are not due to differences in adiposity. Observed associations between adiponectin and diet support the need for future studies exploring the regulation of adiponectin by diet and other environmental factors

How Affirmative Action Context Shapes Collegiate Outcomes at America’s Selective Colleges and Universities

During the 1990s and early 2000s, the affirmative action context in the United States changed. Affirmative action in higher education was banned in several states, and the Supreme Court ruled in Grutter (2003) that affirmative action, while constitutional, should be implemented via holistic evaluation of applicants. In this article, we use two datasets to examine how affirmative action context relates to academic outcomes at selective colleges and universities in the United States before and after the Grutter decision and in states with and without bans on affirmative action. Underrepresented minority students earned higher grades in the period after the Grutter decision than before it, indicating that the holistic evaluation method required by Grutter may enhance educational outcomes for these students. In contrast, we find no support for the idea, proposed by critics of the policy, that banning affirmative action leads to better collegiate outcomes for Black and Latino students at selective institutions

Expression and Structural Studies of Fasciclin I, an Insect Cell Adhesion Molecule

Fasciclin I is a lipid-linked cell-surface glycoprotein that can act as a homophilic adhesion molecule in tissue culture cells. It is thought to be involved in growth cone guidance in the embryonic insect nervous system. To facilitate structure-function studies, we have generated Chinese hamster ovary (CHO) cell lines expressing high levels of cell surface grasshopper and Drosophila fasciclin I. Grasshopper fasciclin I released by phospholipase C cleavage was purified on an immunoaffinity column and single crystals were obtained that diffracted to approximately 5-A resolution. We also generated CHO and Drosophila S2 cell lines that produce a secreted form of fasciclin I. Fasciclin I expressed in S2 cells contains significantly less carbohydrate than the protein expressed in CHO cells, and may therefore be more suitable for crystallization. Biochemical characterization of purified fasciclin I indicates that the extracellular portion exists as a monomer in solution. Circular dichroism studies suggest that fasciclin I is primarily alpha-helical. Its structure is therefore different from other known cell adhesion molecules, which are predicted to be elongated beta-sheet structures. This suggests that fasciclin I may define a new structural motif used to mediate adhesive interactions between cell surfaces