488 research outputs found
Flat-band ferromagnetism induced by off-site repulsions
Density matrix renormalization group method is used to analyze how the
nearest-neighbor repulsion V added to the Hubbard model on 1D triangular
lattice and a railway trestle (t-t') model will affect the electron-correlation
dominated ferromagnetism arising from the interference (frustration). Obtained
phase diagram shows that there is a region in smaller-t' side where the
critical on-site repulsion above which the system becomes ferromagnetic is
reduced when the off-site repulsion is introduced.Comment: 4 pages, RevTex, 6 figures in Postscript, to be published in Phys.
Rev.
Tight-binding study of high-pressure phase transitions in titanium: alpha to omega and beyond
We use a tight-binding total energy method, with parameters determined from a
fit to first-principles calculations, to examine the newly discovered gamma
phase of titanium. Our parameters were adjusted to accurately describe the
alpha Ti-omega Ti phase transition, which is misplaced by density functional
calculations. We find a transition from omega Ti to gamma Ti at 102 GPa, in
good agreement with the experimental value of 116 GPa. Our results suggest that
current density functional calculations will not reproduce the omega Ti-gamma
Ti phase transition, but will instead predict a transition from omega Ti to the
bcc beta Ti phase.Comment: 3 encapsulated Postscript figures, submitted to Phyical Review
Letter
Characterization of Polymeric Proteins from Vitreous and Floury Sorghum Endosperm
Differences in protein content and composition between vitreous and floury endosperm were investigated using a number of different techniques. Differences in protein cross-linking between vitreous and floury endosperm were investigated using differential solubility, size exclusion chromatography (SEC), and analysis of sulfhydryl content and composition. Vitreous endosperm was found to have higher levels of total protein and kafirins, but floury endosperm had a higher proportion of Îł-kafirins than the vitreous. Floury endosperm was found to have higher levels of SDS-soluble proteins than SDS-insoluble proteins extracted using sonication than vitreous endosperm. Conversely, vitreous endosperm had a greater proportion of the insoluble proteins. SEC analysis of the polymeric proteins revealed that the insoluble proteins had more polymeric proteins than did the soluble proteins, indicating greater cross-linking and a larger Mw distribution. Vitreous endosperm was also found to have a greater percentage (i.e., a higher ratio of disulfide to total sulfhydryls) of disulfide bonds than floury endosperm. These results show that the proteins in vitreous endosperm have a higher degree of cross-linking and a greater Mw distribution than those found in floury endosperm
Co-Evolution of quasispecies: B-cell mutation rates maximize viral error catastrophes
Co-evolution of two coupled quasispecies is studied, motivated by the
competition between viral evolution and adapting immune response. In this
co-adaptive model, besides the classical error catastrophe for high virus
mutation rates, a second ``adaptation-'' catastrophe occurs, when virus
mutation rates are too small to escape immune attack. Maximizing both regimes
of viral error catastrophes is a possible strategy for an optimal immune
response, reducing the range of allowed viral mutation rates to a minimum. From
this requirement one obtains constraints on B-cell mutation rates and receptor
lengths, yielding an estimate of somatic hypermutation rates in the germinal
center in accordance with observation.Comment: 4 pages RevTeX including 2 figure
Community perspectives of complex trauma assessment for Aboriginal parents: 'Its important, but how these discussions are held is critical'
Background and Purpose: Becoming a parent can be an exciting and also challenging transition, particularly for parents who have experienced significant hurt in their own childhoods, and may be experiencing âcomplex trauma.â Aboriginal and Torres Strait Islander (Aboriginal) people also experience historical trauma. While the parenting transition is an important time to offer support for parents, it is essential to ensure that the benefits of identifying parents experiencing complex trauma outweigh any risks (e.g., stigmatization). This paper describes views of predominantly Aboriginal stakeholders regarding (1) the relative importance of domains proposed for complex trauma assessment, and (2) how to conduct these sensitive discussions with Aboriginal parents.
Setting and Methods: A co-design workshop was held in Alice Springs (Central Australia) as part of an Aboriginal-led community-based participatory action research project. Workshop participants were 57 predominantly Aboriginal stakeholders with expertise in community, clinical, policy and academic settings. Twelve domains of complex trauma-related distress had been identified in existing assessment tools and through community consultation. Using story-telling and strategies to create safety for discussing complex and sensitive issues, and delphi-style methods, stakeholders rated the level of importance of the 12 domains; and discussed why, by whom, where and how experiences of complex trauma should be explored.
Main Findings: The majority of stakeholders supported the importance of assessing each of the proposed complex trauma domains with Aboriginal parents. However, strong concerns were expressed regarding where, by whom and how this should occur. There was greater emphasis and consistency regarding âqualitiesâ (e.g., caring), rather than specific âattributesâ (e.g., clinician). Six critical overarching themes emerged: ensuring emotional and cultural safety; establishing relationships and trust; having capacity to respond appropriately and access support; incorporating less direct cultural communication methods (e.g., yarning, dadirri); using strengths-based approaches and offering choices to empower parents; and showing respect, caring and compassion.
Conclusion: Assessments to identify Aboriginal parents experiencing complex trauma should only be considered when the prerequisites of safety, trusting relationships, respect, compassion, adequate care, and capacity to respond are assured. Offering choices and cultural and strengths-based approaches are also critical. Without this assurance, there are serious concerns that harms may outweigh any benefits for Aboriginal parents
FirstâinâHuman Study of the Safety and Efficacy of TOL101 Induction to Prevent Kidney Transplant Rejection
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107383/1/ajt12698.pd
Photon and dilepton emission rates from high density quark matter
We compute the rates of real and virtual photon (dilepton) emission from
dense QCD matter in the color-flavor locked (CFL) phase, focusing on results at
moderate densities (3-5 times the nuclear saturation density) and temperatures
MeV. We pursue two approaches to evaluate the electromagnetic
(e.m.) response of the CFL ground state: (i) a direct evaluation of the photon
self energy using quark particle/-hole degrees of freedom, and (ii) a Hidden
Local Symmetry (HLS) framework based on generalized mesonic excitations where
the meson is introduced as a gauge boson of a local SU(3) color-flavor
group. The coupling to generalized two-pion states induces a finite
width and allows to address the issue of vector meson dominance (VMD) in the
CFL phase. We compare the calculated emissivities (dilepton rates) to those
arising from standard hadronic approaches including in-medium effects. For
rather large superconducting gaps (several tens of MeV at moderate densities),
as suggested by both perturbative and nonperturbative estimates, the dilepton
rates from CFL quark matter turn out to be very similar to those obtained in
hadronic many-body calculations, especially for invariant masses above
GeV. A similar observation holds for (real) photon production.Comment: 18 pages, 12 figure
Impact of percutaneous coronary intervention timing on 5-year outcome in patients with non-ST-segment elevation acute coronary syndromes. The âwait a dayâ approach might be safer
Background The OPTIMA trial was a randomised multicentre trial exploring the influence of the timing of percutaneous coronary intervention (PCI) on patient outcomes in an intermediate to high risk non-ST-elevation acute coronary syndrome (NSTE-ACS) population. In order to decide the best treatment strategy for patients presenting with NSTEACS, long-term outcomes are essential. Methods Five-year follow-up data from 133 of the 142 patients could be retrieved (94 %). The primary endpoint was a composite of death and spontaneous myocardial infarction (MI). Spontaneous MI was defined as MI occurring more than 30 days after randomisation. Secondary endpoints were the individual outcomes of death, spontaneous MI or re-PCI. Results No significant difference with respect to the primary endpoint was observed (17.8 vs. 10.1 %; HR 1.55, 95 % CI: 0.73â4.22, p = 0.21). There was no significant difference in mortality rate. However, spontaneous MI was significantly more common in the group receiving immediate PCI (11.0 vs. 1.4 %; HR 4.46, 95 % CI: 1.21â16.50, p = 0.02). We did not find a significant difference between the groups with respect to re-PCI rate. Conclusion There was no difference in the composite of death and spontaneous MI. The trial suggests an increased long-term risk of spontaneous MI for patients treated with immediate PCI
- âŠ