4,089 research outputs found
The state space of short-range Ising spin glasses: the density of states
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
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} 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
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
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
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 CePdIn
We report low-temperature de Haas-van Alphen (dHvA) effect measurements in
magnetic fields up to 35 T of the heavy-fermion superconductor CePdIn.
The comparison of the experimental results with band-structure calculations
implies that the 4 electrons are itinerant rather than localized. The
cyclotron masses estimated at high field are only moderately enhanced, 8 and 14
, 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 CeCoIn, with which CePdIn 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
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
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)
<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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