159 research outputs found

    Weak antiferromagnetism due to Dzyaloshinskii-Moriya interaction in Ba3_3Cu2_2O4_4Cl2_2

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    The antiferromagnetic insulating cuprate Ba3_3Cu2_2O4_4Cl2_2 contains folded CuO2_2 chains with four magnetic copper ions (S=1/2S=1/2) per unit cell. An underlying multiorbital Hubbard model is formulated and the superexchange theory is developed to derive an effective spin Hamiltonian for this cuprate. The resulting spin Hamiltonian involves a Dzyaloshinskii-Moriya term and a more weak symmetric anisotropic exchange term besides the isotropic exchange interaction. The corresponding Dzyaloshinskii-Moriya vectors of each magnetic Cu-Cu bond in the chain reveal a well defined spatial order. Both, the superexchange theory and the complementary group theoretical consideration, lead to the same conclusion on the character of this order. The analysis of the ground-state magnetic properties of the derived model leads to the prediction of an additional noncollinear modulation of the antiferromagnetic structure. This weak antiferromagnetism is restricted to one of the Cu sublattices.Comment: 13 pages, 1 table, 4 figure

    Examining the Association between Intervention-Related Changes in Diet, Physical Activity, and Weight as Moderated by the Food and Physical Activity Environments among Rural, Southern Adults

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    Background Few studies have been conducted in rural areas assessing the influence of community-level environmental factors on residents’ success improving lifestyle behaviors. Objective Our aim was to examine whether 6-month changes in diet, physical activity, and weight were moderated by the food and physical activity environment in a rural adult population receiving an intervention designed to improve diet and physical activity. Design We examined associations between self-reported and objectively measured changes in diet, physical activity, and weight, and perceived and objectively measured food and physical activity environments. Participants were followed for 6 months. Participants/setting Participants were enrolled in the Heart Healthy Lenoir Project, a lifestyle intervention study conducted in Lenoir County, located in rural southeastern North Carolina. Sample sizes ranged from 132 to 249, depending on the availability of the data. Intervention Participants received four counseling sessions that focused on healthy eating (adapted Mediterranean diet pattern) and increasing physical activity. Potential moderating factors Density of and distance to food and physical activity venues, modified food environment index, Walk Score, crime, and perceived nutrition and physical activity neighborhood barriers were the potential mediating factors. Outcome measures Diet quality, physical activity, and weight loss were the outcomes measured. Statistical analyses Statistical analyses included correlation and linear regression and controlling for potential confounders (baseline values of the dependent variables, age, race, education, and sex). Results In adjusted analysis, there was an inverse association between weight change and the food environment, suggesting that participants who lived in a less-healthy food environment lost more weight during the 6-month intervention period (P=0.01). Also, there was a positive association between self-reported physical activity and distance to private gyms (P=0.04) and an inverse association between private gym density and pedometer-measured steps (P=0.03), indicating that those who lived farther from gyms and in areas with lower density of gyms had greater increases in physical activity and steps, respectively. Conclusions Contrary to our hypotheses, results indicated that those living in less-favorable food and physical activity environments had greater improvements in diet, physical activity, and weight, compared to those living in more favorable environments. Additional research should be undertaken to address these paradoxical findings and, if confirmed, to better understand them

    Eating Well While Dining Out: Collaborating with Local Restaurants to Promote Heart Healthy Menu Items

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    Background: Because Americans commonly consume restaurant foods with poor dietary quality, effective interventions are needed to improve food choices at restaurants. Purpose: The purpose of this study was to design and evaluate a restaurant-based intervention to help customers select and restaurants promote heart healthy menu items with healthful fats and high-quality carbohydrates. Methods: The intervention included table tents outlining 10 heart healthy eating tips, coupons promoting healthy menu items, an information brochure, and link to study website. Pre- and postintervention surveys were completed by restaurant managers and customers completed a brief “intercept” survey. Results: Managers (n = 10) reported that the table tents and coupons were well received, and several noted improved personal nutrition knowledge. Overall, 4214 coupons were distributed with 1244 (30%) redeemed. Of 300 customers surveyed, 126 (42%) noticed the table tents and, of these, 115 (91%) considered the nutrition information helpful, 42 (33%) indicated that the information influenced menu items purchased, and 91 (72%) reported that the information will influence what they order in the future. Discussion: The intervention was well received by restaurant managers and positively influenced menu item selection by many customers. Translation to Health Education Practice: Further research is needed to assess effective strategies for scaling up and sustaining this intervention approach

    Validity and Reliability of a Brief Dietary Assessment Questionnaire in a Cardiac Rehabilitation Program

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    Purpose: Dietary assessment is vital to inform individualized nutrition care and to evaluate the success of interventions aimed at improving diet for participants in cardiac rehabilitation (CR) programs. The purpose of this study was to assess the validity and reliability of an instrument developed to reflect current evidence-informed dietary recommendations advocated to reduce cardiovascular risk. Methods: This study was conducted at a single CR program at the University of North Carolina, Chapel Hill. Two dietary assessments were administered: Picture Your Plate (PYP) and a reference instrument, the Harvard/Willett Food Frequency Questionnaire (HWFFQ). The PYP is a modification of a previously validated instrument, the Dietary Risk Assessment-New Leaf (DRA-New Leaf). Concurrent validity was assessed by comparing the PYP total score with 3 diet quality indexes (Alternative Health Eating Index [AHEI], Dietary Approaches to Stop Hypertension [DASH], and Alternative Mediterranean Diet [aMED]) calculated from the HWFFQ and by assessment of agreement in tertile cross-classification. An intraclass correlation (ICC) was calculated to assess test-retest reliability. Results: Among the 108 participants, crude and adjusted Spearmen correlation coefficients between the PYP and 3 indexes of dietary quality were AHEI-2010 (0.71-0.72), DASH (0.70-0.71), and aMED (0.52-0.58) (P <.0001, all comparisons). Agreement of tertiles comparing PYP and AHEI-2010 was 67% and the score in opposite tertiles was 6%. The weighted kappa value (Îşw) = 0.71. The test-retest ICC was 0.91 (95% CI, 0.85-0.93; n = 91). Conclusions: Results support the PYP as a valid and reliable dietary assessment tool for use in CR programs. Continued research in additional CR program populations is recommended

    Successful long-term weight loss among participants with diabetes receiving an intervention promoting an adapted Mediterranean-style dietary pattern: The Heart Healthy Lenoir Project

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    Objective: To examine weight change by diabetes status among participants receiving a Mediterraneanstyle diet, physical activity, and weight loss intervention adapted for delivery in the southeastern USA, where rates of cardiovascular disease (CVD) are disproportionately high. Research design and methods: The intervention included: Phase I (months 1-6), an individually tailored intervention promoting a Mediterranean-style dietary pattern and increased walking; Phase II (months 7-12), option of a 16-week weight loss intervention for those with BMI≥25 kg/m2 offered as 16 weekly group sessions or 5 group sessions and 10 phone calls, or a lifestyle maintenance intervention; and Phase III (months 13-24), weight loss maintenance intervention for those losing ≥8 pounds with all others receiving a lifestyle maintenance intervention. Weight change was assessed at 6, 12, and 24-month follow-up. Results: Baseline characteristics (n=339): mean age 56, 77% female, 65% African-American, 124 (37%) with diabetes; mean weight 103 kg for those with diabetes and 95 kg for those without. Among participants with diabetes, average weight change was -1.2 kg (95% CI -2.1 to -0.4) at 6 months (n=92), -1.5 kg (95% CI -2.9 to -0.2) at 12 months (n=96), and -3.7 kg (95% CI -5.2 to -2.1) at 24 months (n=93). Among those without diabetes, weight change was -0.4 kg (95% CI -1.4 to 0.6) at 24 months (n=154). Conclusions: Participants with diabetes experienced sustained weight loss at 24-month follow-up. High-risk US populations with diabetes may experience clinically important weight loss from this type of lifestyle intervention

    Orbital state and magnetic properties of LiV_2 O_4

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    LiV_2 O_4 is one of the most puzzling compounds among transition metal oxides because of its heavy fermion like behavior at low temperatures. In this paper we present results for the orbital state and magnetic properties of LiV_2 O_4 obtained from a combination of density functional theory within the local density approximation and dynamical mean-field theory (DMFT). The DMFT equations are solved by quantum Monte Carlo simulations. The trigonal crystal field splits the V 3d orbitals such that the a_{1g} and e_{g}^{pi} orbitals cross the Fermi level, with the former being slightly lower in energy and narrower in bandwidth. In this situation, the d-d Coulomb interaction leads to an almost localization of one electron per V ion in the a_{1g} orbital, while the e_{g}^{pi} orbitals form relatively broad bands with 1/8 filling. 2The theoretical high-temperature paramagnetic susceptibility chi(T) follows a Curie-Weiss law with an effective paramagnetic moment p_{eff}=1.65 in agreement with the experimental results.Comment: 11 pages, 10 figures, 2 table

    The Political Economy of US Military Spending

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    The causes of the dramatic rise in military spending in the post-war era have been the subject of much political and academic controversy. No extant formulation seems to provide a compelling explanation of the dynamics involved in the levels of, and rates of change in, such spending. In light of this, the authors develop a new model, based mainly on a political-business cycle argument, to account for these dynamics. The basic proposition in this model is that variations in national defense spending arise from political considerations which are related to real and desired conditions within the national economy. Applying this model to the experience of the United States 1948-1976, the authors show that it has a large measure of empirical validity. If one removes the effects of war-time mobilization, it is clear that for the United States the principal driving forces in military spending dynamics were (1) the perceived utility of such spending in stabilizing aggregate demand, (2) the political or electoral value of the perceived economic effects arising out of such spending, and (3) the pressures of institutional-constituency demands.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68958/2/10.1177_002234337901600202.pd

    Applicability of precision medicine approaches to managing hypertension in rural populations

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    As part of the Heart Healthy Lenoir Project, we developed a practice level intervention to improve blood pressure control. The goal of this study was: (i) to determine if single nucleotide polymorphisms (SNPs) that associate with blood pressure variation, identified in large studies, are applicable to blood pressure control in subjects from a rural population; (ii) to measure the association of these SNPs with subjects’ responsiveness to the hypertension intervention; and (iii) to identify other SNPs that may help understand patient-specific responses to an intervention. We used a combination of candidate SNPs and genome-wide analyses to test associations with either baseline systolic blood pressure (SBP) or change in systolic blood pressure one year after the intervention in two genetically defined ancestral groups: African Americans (AA) and Caucasian Americans (CAU). Of the 48 candidate SNPs, 13 SNPs associated with baseline SBP in our study; however, one candidate SNP, rs592582, also associated with a change in SBP after one year. Using our study data, we identified 4 and 15 additional loci that associated with a change in SBP in the AA and CAU groups, respectively. Our analysis of gene-age interactions identified genotypes associated with SBP improvement within different age groups of our populations. Moreover, our integrative analysis identified AQP4-AS1 and PADI2 as genes whose expression levels may contribute to the pleiotropy of complex traits involved in cardiovascular health and blood pressure regulation in response to an intervention targeting hypertension. In conclusion, the identification of SNPs associated with the success of a hypertension treatment intervention suggests that genetic factors in combination with age may contribute to an individual’s success in lowering SBP. If these findings prove to be applicable to other populations, the use of this genetic variation in making patient-specific interventions may help providers with making decisions to improve patient outcomes. Further investigation is required to determine the role of this genetic variance with respect to the management of hypertension such that more precise treatment recommendations may be made in the future as part of personalized medicine
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