1,649 research outputs found

    Universality in the Gross-Neveu model

    Full text link
    We consider universal finite size effects in the large-N limit of the continuum Gross-Neveu model as well as in its discretized versions with Wilson and with staggered fermions. After extrapolation to zero lattice spacing the lattice results are compared to the continuum values.Comment: Lattice2004(theory

    Influence of Hybridization on the Properties of the Spinless Falicov-Kimball Model

    Full text link
    Without a hybridization between the localized f- and the conduction (c-) electron states the spinless Falicov-Kimball model (FKM) is exactly solvable in the limit of high spatial dimension, as first shown by Brandt and Mielsch. Here I show that at least for sufficiently small c-f-interaction this exact inhomogeneous ground state is also obtained in Hartree-Fock approximation. With hybridization the model is no longer exactly solvable, but the approximation yields that the inhomogeneous charge-density wave (CDW) ground state remains stable also for finite hybridization V smaller than a critical hybridization V_c, above which no inhomogeneous CDW solution but only a homogeneous solution is obtained. The spinless FKM does not allow for a ''ferroelectric'' ground state with a spontaneous polarization, i.e. there is no nonvanishing -expectation value in the limit of vanishing hybridization.Comment: 7 pages, 6 figure

    Preparing for N(f) = 2 simulations at small lattice spacings

    Get PDF
    We discuss some large effects of dynamical fermions. One is a cutoff effect, others concern the contribution of multi-pion states to correlation functions and are expected to survive the continuum limit. We then turn to the preparation for simulations at small lattice spacings which we are planning down to around a=0.04fm in order to understand the size of O(a^2)-effects of the standard O(a)-improved theory. The dependence of the lattice spacing on the bare coupling is determined through the Schr'odinger functional renormalized coupling

    Gender Transformative Impacts from Watershed Interventions: Insights from a Mixed-Methods Study in the Bundelkhand Region of India

    Get PDF
    This study examined gender perspectives on water security by exploring an integrated water management approach for agriculture, livestock, and human consumption. The data were generated in a watershed project to enhance drought resilience of farming through groundwater recharge and agroforestry interventions in the water-scarce Bundelkhand region of Uttar Pradesh in central India. Post-intervention, a quantitative survey and qualitative gender and social analysis tools were applied to understand the benefits of the interventions for women, men, and the community as a whole. Quantitative data were collected from 700 individuals in five villages (three treatment villages and two villages where watershed interventions were not implemented). In addition, 33 semi-structured interviews and eight focus group discussions were conducted to understand local gender norms at the project sites. Data analysis revealed that the community benefits accrued from the watershed interventions included increased crop productivity and diversification of agriculture and livelihoods. However, strict patriarchal norms restricted the visibility, mobility, and communication of women within the household and community during the interventions. Considering gender diversity, this study identifies that women can benefit from participating in watershed interventions and provides a deeper understanding of the constraints and barriers to women’s participation in such projects, including economic, social, and cultural factors. The construction of check dams reduced women’s time per day for fetching water by about 29%. Groundwater level increases reduced the effort required of women to draw water from open wells and hand pumps. Female education is a significant factor related to the benefits of watershed interventions, and regression analysis indicated that households with higher levels of education of adult women were significantly more likely to benefit from the interventions than other households. To avoid perpetuation of the exclusion of diverse local knowledge and gender inequality at the community level, mechanisms must be developed and adjusted continuously such that whole communities, including men and women, are empowered to participate in the decision-making process at various levels and for different purposes. When implementing watershed projects in a highly patriarchal context, as in the Bundelkhand region where women are hidden behind the strong presence of men, advocacy of behavioral change communication must be implemented regularly. The community needs to be sensitized toward systematic and gendersensitive institution building, social engagement, and capacity development for local as well as global water security

    Fiberoptic endoscopic evaluation of swallowing in intensive care unit patients

    Get PDF
    Aspiration in critically ill patients frequently causes severe co-morbidity. We evaluated a diagnostic protocol using routine FEES in critically ill patients at risk to develop aspiration following extubation. We instructed intensive care unit physicians on specific risk factors for and clinical signs of aspiration following extubation in critically ill patients and offered bedside FEES for such patients. Over a 45-month period, we were called to perform 913 endoscopic examinations in 553 patients. Silent aspiration or aspiration with acute symptoms (cough or gag reflex as the bolus passed into the trachea) was detected in 69.3% of all patients. Prolonged non-oral feeding via a naso-gastric tube was initiated in 49.7% of all patients. In 13.2% of patients, a percutaneous endoscopic gastrostomy was initiated as a result of FEES findings, and in 6.3% an additional tracheotomy to prevent aspiration had to be initiated. In 59 out of 258 patients (22.9%), tracheotomies were closed, and 30.7% of all 553 patients could be managed with the immediate onset of an oral diet and compensatory treatment procedures. Additional radiological examinations were not required. FEES in critically ill patients allows for a rapid evaluation of deglutition and for the immediate initiation of symptom-related rehabilitation or for an early resumption of oral feeding

    The ESR1 (6q25) locus is associated with calcaneal ultrasound parameters and radial volumetric bone mineral density in European men

    Get PDF
    <p><b>Purpose:</b> Genome-wide association studies (GWAS) have identified 6q25, which incorporates the oestrogen receptor alpha gene (ESR1), as a quantitative trait locus for areal bone mineral density (BMD(a)) of the hip and lumbar spine. The aim of this study was to determine the influence of this locus on other bone health outcomes; calcaneal ultrasound (QUS) parameters, radial peripheral quantitative computed tomography (pQCT) parameters and markers of bone turnover in a population sample of European men.</p> <p><b>Methods:</b> Eight single nucleotide polymorphisms (SNP) in the 6q25 locus were genotyped in men aged 40-79 years from 7 European countries, participating in the European Male Ageing Study (EMAS). The associations between SNPs and measured bone parameters were tested under an additive genetic model adjusting for centre using linear regression.</p> <p><b>Results:</b> 2468 men, mean (SD) aged 59.9 (11.1) years had QUS measurements performed and bone turnover marker levels measured. A subset of 628 men had DXA and pQCT measurements. Multiple independent SNPs showed significant associations with BMD using all three measurement techniques. Most notably, rs1999805 was associated with a 0.10 SD (95%CI 0.05, 0.16; p = 0.0001) lower estimated BMD at the calcaneus, a 0.14 SD (95%CI 0.05, 0.24; p = 0.004) lower total hip BMD(a), a 0.12 SD (95%CI 0.02, 0.23; p = 0.026) lower lumbar spine BMD(a) and a 0.18 SD (95%CI 0.06, 0.29; p = 0.003) lower trabecular BMD at the distal radius for each copy of the minor allele. There was no association with serum levels of bone turnover markers and a single SNP which was associated with cortical density was also associated with cortical BMC and thickness.</p> <p><b>Conclusions:</b> Our data replicate previous associations found between SNPs in the 6q25 locus and BMD(a) at the hip and extend these data to include associations with calcaneal ultrasound parameters and radial volumetric BMD.</p&gt

    Chromosome assignment of two cloned DNA probes hybridizing predominantly to human sex chromosomes

    Get PDF
    In situ hybridization experiments were carried out with two clones, YACG 35 and 2.8, which had been selected from two genomic libraries strongly enriched for the human Y chromosome. Besides the human Y chromosome, both sequences strongly hybridized to the human X chromosome, with few minor binding sites on autosomes. In particular, on the X chromosome DNA from clone YACG 35 hybridized to the centromeric region and the distal part of the short arm (Xp2.2). On the Y chromosome, the sequence was assigned to one site situated in the border region between Yq1.1 and Yq1.2. DNA from clone 2.8 also hybridized to the centromeric region of the X and the distal part of the short arm (Xq2.2). On the Y, however, two binding sites were observed (Yp1.1 and Yq1.2). The findings indicate that sex chromosomal sequences may be localized in homologous regions (as suggested from meiotic pairing) but also at ectopic sites

    Theory of Electronic Ferroelectricity

    Full text link
    We present a theory of the linear and nonlinear optical characteristics of the insulating phase of the Falicov-Kimball model within the self-consistent mean-field approximation. The Coulomb attraction between the itinerant d-electrons and the localized f-holes gives rise to a built-in coherence between the d and f-states, which breaks the inversion symmetry of the underlying crystal, leading to: (1) electronic ferroelectricity, (2) ferroelectric resonance, and (3) a nonvanishing susceptibility for second-harmonic generation. As experimental tests of such a built-in coherence in mixed-valent compounds we propose measurements of the static dielectric constant, the microwave absorption spectrum, and the dynamic second-order susceptibility.Comment: 15 pages, 5 PostScript figures, submitted to Physical Review
    • …
    corecore