496 research outputs found

    Gaseous Air Pollutants and Hospitalization for Respiratory Disease in the Neonatal Period

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    OBJECTIVE: Current levels of ambient air pollution are associated with morbidity and mortality in the general population. To determine the influence of gaseous air pollutants on neonatal respiratory morbidity, we tested the association between daily respiratory hospitalizations and daily concentrations of ambient air pollution gases: ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide, in 11 large Canadian cities. STUDY DESIGN: Daily time-series analyses were employed and results were adjusted for day of the week, temperature, barometric pressure, and relative humidity. RESULTS: The percent increases in hospitalization associated with an increase in air pollution equivalent to its interquartile range were 3.35 [95% confidence interval (CI), 1.73–4.77] for O(3), 2.85 (95% CI, 1.68–4.02) for NO(2), 1.66 (95% CI, 0.63–2.69) for SO(2), and 1.75 (95% CI, 0.48–3.02) for CO. The independent effect of all pollutants combined was 9.61% (95% CI, 4.52–14.7%). CONCLUSION: Our results suggest that neonates are experiencing adverse effects of air pollution at current levels in Canada, and that accounts for a significant proportion of hospitalizations in this subgroup

    Heavy holes: precursor to superconductivity in antiferromagnetic CeIn3

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    Numerous phenomenological parallels have been drawn between f- and d- electron systems in an attempt to understand their display of unconventional superconductivity. The microscopics of how electrons evolve from participation in large moment antiferromagnetism to superconductivity in these systems, however, remains a mystery. Knowing the origin of Cooper paired electrons in momentum space is a crucial prerequisite for understanding the pairing mechanism. Of especial interest are pressure-induced superconductors CeIn3 and CeRhIn5 in which disparate magnetic and superconducting orders apparently coexist - arising from within the same f-electron degrees of freedom. Here we present ambient pressure quantum oscillation measurements on CeIn3 that crucially identify the electronic structure - potentially similar to high temperature superconductors. Heavy pockets of f-character are revealed in CeIn3, undergoing an unexpected effective mass divergence well before the antiferromagnetic critical field. We thus uncover the softening of a branch of quasiparticle excitations located away from the traditional spin-fluctuation dominated antiferromagnetic quantum critical point. The observed Fermi surface of dispersive f-electrons in CeIn3 could potentially explain the emergence of Cooper pairs from within a strong moment antiferromagnet.Comment: To appear in Proceedings of the National Academy of Science

    Center for Mental Health Services Research Dissemination Activities

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    Introduction The University of Massachusetts Medical School (UMMS) Center for Mental Health Services Research (CMHSR) conducts research to enhance services, improve the quality of life, and promote recovery for people with behavioral health conditions. The Center was founded in 1993 as a Massachusetts Department of Mental Health Research Center of Excellence. Center faculty receive funding from a variety of federal, state and foundation sources. The Center’s focus on community-based research and engagement with providers, consumers and families also carries the message of hope for the many adults, children, adolescents and families living with mental illness. The Mental Health Agency Research Network (MHARN) expands on the dissemination and research functions of CMHSR to reach providers serving DMH clients across the Commonwealth of Massachusetts. The goals of the MHARN include Dissemination, Engagement and Collaboration as a way to facilitate the translation of research findings into practice and bring together providers with researchers to engage in new research on services provided in the community. Four Research Subject Areas: Child, Youth & Family Mental Health Law, Ethics & Mental Health Multicultural Research Rehabilitation, Recovery & Wellness The Dissemination Series Products for a diverse audience including clinicians/providers, mental health service users and their families, and researchers. Psychiatry Issue Briefs Issue briefs focus on translating research findings into concise, user-friendly information that is accessible to all Research You Can Use A one-page summary of research findings and recommendations specifically developed for busy providers Research in the Works Summarizes current and ongoing research project

    Differential expression of RANK, RANK-L, and osteoprotegerin by synovial fluid neutrophils from patients with rheumatoid arthritis and by healthy human blood neutrophils

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    Functional links between bone remodeling and the immune system in chronic inflammatory arthritis are mediated, in part, by the ligand of receptor activator of nuclear factor-kappa-B (RANK-L). Because neutrophils play a crucial role in chronic inflammation, the goal of this study was to determine whether proteins of the RANK/RANK-L pathway are expressed by synovial fluid (SF) neutrophils from patients with rheumatoid arthritis (RA) and to characterize this pathway in normal human blood neutrophils. The expression of RANK-L, osteoprotegerin (OPG), RANK, and tumor necrosis factor receptor-associated factor 6 (TRAF6) was determined by polymerase chain reaction, enzyme-linked immunosorbent assay, Western blotting, and cytofluorometry. RANK signaling was analyzed by the degradation of inhibitor of kappaB-alpha (I-ÎșB-α). SF neutrophils from patients with RA express and release OPG and express the membrane-associated forms of RANK-L and RANK. In contrast, normal blood neutrophils express only the membrane-associated form of RANK-L. They do not express the mRNAs encoding OPG and RANK. SF neutrophils from RA patients and normal blood neutrophils release no soluble RANK-L. They express the mRNA for TRAF6. The expression of OPG and RANK by normal human blood neutrophils, however, can be induced by interleukin-4 + tumor necrosis factor-alpha and by SFs from patients with RA. In contrast, SFs from patients with osteoarthritis do not induce the expression of OPG and RANK. Moreover, the addition of RANK-L to normal blood neutrophils pretreated by SF from patients with RA decreased I-ÎșB-α, indicating that RANK signaling by neutrophils stimulated with SF is associated with nuclear factor-kappa-B activation. In summary, RANK-L is expressed by inflammatory and normal neutrophils, unlike OPG and RANK, which are expressed only by neutrophils exposed to an inflammatory environment. Taken together, these results suggest that neutrophils may contribute to bone remodeling at inflammatory sites where they are present in significantly large numbers

    Fermi-surface reconstruction and two-carrier model for the Hall effect in YBa2Cu4O8

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    Pulsed field measurements of the Hall resistivity and magnetoresistance of underdoped YBa2Cu4O8 are analyzed self-consistently using a simple model based on coexisting electron and hole carriers. The resultant mobilities and Hall numbers are found to vary markedly with temperature. The conductivity of the hole carriers drops by one order of magnitude below 30 K, explaining the absence of quantum oscillations from these particular pockets. Meanwhile the Hall coefficient of the electron carriers becomes strongly negative below 50 K. The overall quality of the fits not only provides strong evidence for Fermi-surface reconstruction in Y-based cuprates, it also strongly constrains the type of reconstruction that might be occurring.Comment: 5 pages, 4 figures, updated after publication in Physical Review B (Rapid Communication

    Reconstruction of the Fermi surface in the pseudogap state of cuprates

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    Reconstruction of the Fermi surface of high-temperature superconducting cuprates in the pseudogap state is analyzed within nearly exactly solvable model of the pseudogap state, induced by short-range order fluctuations of antiferromagnetic (AFM, spin density wave (SDW), or similar charge density wave (CDW)) order parameter, competing with superconductivity. We explicitly demonstrate the evolution from "Fermi arcs" (on the "large" Fermi surface) observed in ARPES experiments at relatively high temperatures (when both the amplitude and phase of density waves fluctuate randomly) towards formation of typical "small" electron and hole "pockets", which are apparently observed in de Haas - van Alfen and Hall resistance oscillation experiments at low temperatures (when only the phase of density waves fluctuate, and correlation length of the short-range order is large enough). A qualitative criterion for quantum oscillations in high magnetic fields to be observable in the pseudogap state is formulated in terms of cyclotron frequency, correlation length of fluctuations and Fermi velocity.Comment: 4 pages, 3 figure

    Isotropic three-dimensional gap in the iron-arsenide superconductor LiFeAs from directional heat transport measurements

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    The thermal conductivity k of the iron-arsenide superconductor LiFeAs (Tc ~ 18K) was measured in single crystals at temperatures down to T~50mK and in magnetic fields up to H=17T, very close to the upper critical field Hc2~18T. For both directions of the heat current, parallel and perpendicular to the tetragonal c-axis, a negligible residual linear term k/T is found as T ->0, revealing that there are no zero-energy quasiparticles in the superconducting state. The increase in k with magnetic field is the same for both current directions and it follows closely the dependence expected for an isotropic superconducting gap. There is no evidence of multi-band character, whereby the gap would be different on different Fermi-surface sheets. These findings show that the superconducting gap in LiFeAs is isotropic in 3D, without nodes or deep minima anywhere on the Fermi surface. Comparison with other iron-pnictide superconductors suggests that a nodeless isotropic gap is a common feature at optimal doping (maximal Tc).Comment: 4 pages, 3 figure

    The Mental Health Agency Research Network (MHARN): Developing a statewide network for knowledge sharing, technical assistance & collaborative research

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    The Mental Health Agency Research Network (MHARN) is a developing network for sharing knowledge and research collaboration between the UMMS Dept. of Psychiatry and other academics, DMH personnel, community providers, consumers and family members. Its mission is to close the gap between science and service in mental health services in Massachusetts by improving implementation of evidence based practices to benefit consumers. The MHARN provides a structure and mechanism for the Center for Mental Health Services Research (CMHSR) to better engage with DMH staff and community agencies around the state. As experience and research on science-to-service has demonstrated that dissemination of information about research findings is not sufficient to bring about changes in practice and benefits to consumers, the MHARN will incorporate principles and practices of the emerging science of implementation research

    New Phase Induced by Pressure in the Iron-Arsenide Superconductor K-Ba122

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    The electrical resistivity rho of the iron-arsenide superconductor Ba1-xKxFe2As2 was measured in applied pressures up to 2.6 GPa for four underdoped samples, with x = 0.16, 0.18, 0.19 and 0.21. The antiferromagnetic ordering temperature T_N, detected as a sharp anomaly in rho(T), decreases linearly with pressure. At pressures above around 1.0 GPa, a second sharp anomaly is detected at a lower temperature T_0, which rises with pressure. We attribute this second anomaly to the onset of a phase that causes a reconstruction of the Fermi surface. This new phase expands with increasing x and it competes with superconductivity. We discuss the possibility that a second spin-density wave orders at T_0, with a Q vector distinct from that of the spin-density wave that sets in at T_N.Comment: Two higher K concentrations were added, revealing a steady expansion of the new phase in the T-P phase diagra
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