4,089 research outputs found

    The state space of short-range Ising spin glasses: the density of states

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    The state space of finite square and cubic Ising spin glass models is analysed in terms of the global and the local density of states. Systems with uniform and gaussian probability distribution of interactions are compared. Different measures for the local state density are presented and discussed. In particular the question whether the local density of states grows exponentially or not is considered. The direct comparison of global and local densities leads to consequences for the structure of the state space.Comment: 18 pages (including 6 figures); submitted to Z.f.Physik

    A modern study of HD166734: a massive supergiant system

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    Aims. HD166734 is an eccentric eclipsing binary system composed of two supergiant O-type stars, orbiting with a 34.5-day period. In this rare configuration for such stars, the two objects mainly evolve independently, following single-star evolution so far. This system provides a chance to study the individual parameters of two supergiant massive stars and to derive their real masses. Methods. An intensive monitoring was dedicated to HD166734.We analyzed mid- and high-resolution optical spectra to constrain the orbital parameters of this system. We also studied its light curve for the first time, obtained in the VRI filters. Finally, we disentangled the spectra of the two stars and modeled them with the CMFGEN atmosphere code in order to determine the individual physical parameters. Results. HD166734 is a O7.5If+O9I(f) binary. We confirm its orbital period but we revise the other orbital parameters. In comparison to what we found in the literature, the system is more eccentric and, now, the hottest and the most luminous component is also the most massive one. The light curve exhibits only one eclipse and its analysis indicates an inclination of 63.0{\deg} ±\pm 2.7{\deg}. The photometric analysis provides us with a good estimation of the luminosities of the stars, and therefore their exact positions in the Hertzsprung-Russell diagram. The evolutionary and the spectroscopic masses show good agreement with the dynamical masses of 39.5 Msun for the primary and 33.5 Msun for the secondary, within the uncertainties. The two components are both enriched in helium and in nitrogen and depleted in carbon. In addition, the primary also shows a depletion in oxygen. Their surface abundances are however not different from those derived from single supergiant stars, yielding, for both components, an evolution similar to that of single stars.Comment: 13 pages, 13 figures, A&A accepte

    Intrauterine repair of gastroschisis in fetal rabbits

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    Objective: Infants with gastroschisis (GS) still face severe morbidity. Prenatal closure may prevent gastrointestinal organ damage, but intrauterine GS repair (GSR) has not been established yet. Methods: In New Zealand White rabbits we developed and compared GS versus GSR: creation of GS was achieved by hysterotomy, right-sided laparotomy of the fetus and pressure on the abdominal wall to provoke evisceration. GSR was accomplished by careful reposition of eviscerated organs and a running suture of the fetal abdominal wall. For study purposes, 18 animals were divided equally into 3 groups: GS, GS with GSR after 2 h, and unmanipulated controls (C). Vitality was assessed by echocardiography. After 5 h all animals were sacrificed. Results: GSR inflicted no increased mortality, because all fetuses survived GS or GS with GSR. All fetuses with GS demonstrated significant evisceration of abdominal organs. In contrast, the abdominal wall of the fetuses from GSR was intact. Conclusion:The present animal model demonstrated the technical feasibility and success of an intrauterine repair of GS for the first time. However, further long-term studies (leaving GS and GSR in utero for several days) will be necessary to compare survival rates and intestinal injury, motility or absorption. The clinical application of GSR in utero remains a vision so far. Copyright (C) 2003 S. Karger AG, Basel

    Joint International Grassland and International Rangeland Congress Kenya 2021: Grasslands Summary

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    This summary used as its main sources the plenary and keynote papers and talks in Sub-theme 2: Forage Production and Utilization and Sub-theme 3: Livestock Production Systems as well as a sampling of oral talks presented at the XXIV International Grassland Congress (IGC). This IGC was held virtually and jointly with the International Rangeland Congress and hosted in Nairobi, Kenya during 23-29 October 2021. The XXIV IGC was also the first to be held on the African continent in Congress\u27 94-year history. The summary is further focused on that information presented under the concept cultivated grasslands (e.g., a small number of species exposed to high management inputs) and is independent of the rangeland summary presented elsewhere in these proceedings. As with all previous IGCs, pasture productivity, quality, and persistence were emphasized, but understandably, mainly for aspects relevant to Africa and the tropics. However, carbon sequestration, pasture resilience, adaptation, and greenhouse gas mitigation were addressed as part of cultivated grassland management. These additional concerns will challenge everyone as new technological advances are deployed into global agriculture. Impacts on social, environmental, and economic issues remain important, but ill-defined. Future considerations include improving research and out-reach programs for the tropics, but especially adaptation of both tropical and temperate systems to projected climate change issues such as higher temperatures and inconsistent rainfall for all geographies. Fitting the current sustainability narrative to the science and not the other way around is important going forward. Finally, one must keep in mind how pastoralists and producers will be impacted with any future research projects and policy changes

    Coplanar stripline antenna design for optically detected magnetic resonance on semiconductor quantum dots

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    We report on the development and testing of a coplanar stripline antenna that is designed for integration in a magneto-photoluminescence experiment to allow coherent control of individual electron spins confined in single self-assembled semiconductor quantum dots. We discuss the design criteria for such a structure which is multi-functional in the sense that it serves not only as microwave delivery but also as electrical top gate and shadow mask for the single quantum dot spectroscopy. We present test measurements on hydrogenated amorphous silicon, demonstrating electrically detected magnetic resonance using the in-plane component of the oscillating magnetic field created by the coplanar stripline antenna necessary due to the particular geometry of the quantum dot spectroscopy. From reference measurements using a commercial electron spin resonance setup in combination with finite element calculations simulating the field distribution in the structure, we obtain an average magnetic field of ~0.2mT at the position where the quantum dots would be integrated into the device. The corresponding pi-pulse time of ~0.3us fully meets the requirements set by the high sensitivity optical spin read-out scheme developed for the quantum dot

    Quasi-two-dimensional Fermi surfaces of the heavy-fermion superconductor Ce2_2PdIn8_8

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    We report low-temperature de Haas-van Alphen (dHvA) effect measurements in magnetic fields up to 35 T of the heavy-fermion superconductor Ce2_2PdIn8_8. The comparison of the experimental results with band-structure calculations implies that the 4ff electrons are itinerant rather than localized. The cyclotron masses estimated at high field are only moderately enhanced, 8 and 14 m0m_0, but are substantially larger than the corresponding band masses. The observed angular dependence of the dHvA frequencies suggests quasi-two-dimensional Fermi surfaces in agreement with band-structure calculations. However, the deviation from ideal two dimensionality is larger than in CeCoIn5_5, with which Ce2_2PdIn8_8 bears a lot of similarities. This subtle distinction accounts for the different superconducting critical temperatures of the two compounds.Comment: accepted to Phys. Rev.

    A Review of the Biology, Ecology and Behavior of Velvety Tree Ants of North America

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    Ants belonging to the genus Liometopum are regionally distributed across North America, Europe and Asia. L. apiculatum Mayr, L. luctuosum Wheeler, and L. occidentale Emery are found in western North America and are referred to as velvety tree ants. Very little is known about the biology of these species, but they are similar. They are typically associated with trees and shrubs and are frequently found tending hemipterans. All three species are are easily disturbed and and resort to highly aggressive behaviors including the use of strong alarm odors. The following review is intended to summarize the literature regarding the biology and control of these species. Special emphasis has been given to factors that might be important in their control and gaps in our current knowledge

    A Review of the Biology, Ecology and Behavior of Velvety Tree Ants of North America

    Get PDF
    Ants belonging to the genus Liometopum are regionally distributed across North America, Europe and Asia. L. apiculatum Mayr, L. luctuosum Wheeler, and L. occidentale Emery are found in western North America and are referred to as velvety tree ants. Very little is known about the biology of these species, but they are similar. They are typically associated with trees and shrubs and are frequently found tending hemipterans. All three species are are easily disturbed and and resort to highly aggressive behaviors including the use of strong alarm odors. The following review is intended to summarize the literature regarding the biology and control of these species. Special emphasis has been given to factors that might be important in their control and gaps in our current knowledge.</span

    Health-Related Quality of Life after Ischemic Stroke: The Impact of Pharmaceutical Interventions on Drug Therapy (Pharmaceutical Care Concept)

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    <p>Abstract</p> <p>Background</p> <p>Health-related quality of life (HRQoL) after stroke is an important healthcare measure. Pharmaceutical Care (PC) is an evolving concept to optimize drug-therapy, minimize drug-related problems, and improve HRQoL of patients. The purpose of this study was to evaluate the impact of PC on HRQoL, as determined by Short Form 36 (SF-36) among patients after TIA or ischemic stroke one-year following their initial entry in hospital.</p> <p>Methods</p> <p>Patients were assigned to either an intervention (IG) or a control group (CG). The individual assignment of the patient to IG or CG depended on the community pharmacy to which the patients were assigned for care. Community pharmacies either delivered standard care (CG) or provided intensified PC (IG). Pharmacists who are members of the "Quality Assurance Working Group" (QAWG) provided PC for patients in IG.</p> <p>Results</p> <p>255 patients were recruited (IG: n = 90; CG: n = 165) between 06/2004 to 01/2007. During the study, the HRQoL of the patients in IG did not change significantly. In the CG, a significant decrease in the HRQoL was observed in 7/8 subscales and in both summary measures of SF-36.</p> <p>Conclusions</p> <p>This is the first follow-up study in Germany involving a major community hospital, rehabilitation hospitals, community pharmacies and general practitioners investigating the impact of PC on HRQoL of patients after ischemic stroke. Our findings indicate that an intensified education and care of patients after ischemic stroke by dedicated pharmacists based on a concept of PC may maintain the HRQoL of IG patients.</p
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