3,231 research outputs found
Cholecystitis in Pregnancy
Biliary tract disease is a relatively uncommon, heterogenous disease in pregnancy. Specifically,
acute cholecystitis can be especially difficult to recognize in pregnancy. However, once diagnosed,
the initial management plan should be conservative and include antibiotic therapy. Subsequent
management depends on the gestational age at diagnosis. Surgical therapy, when indicated,
should not be delayed and a planned intervention during the second trimester appears to offer a
better outcome than surgery performed under emergent conditions
The Milky Way's stellar halo - lumpy or triaxial?
We present minimum chi-squared fits of power law and Hernquist density
profiles to F-turnoff stars in eight 2.5 deg wide stripes of SDSS data: five in
the North Galactic Cap and three in the South Galactic cap. Portions of the
stellar Galactic halo that are known to contain large streams of tidal debris
or other lumpy structure, or that may include significant contamination from
the thick disk, are avoided. The data strongly favor a model that is not
symmetric about the Galaxy's axis of rotation. If included as a free parameter,
the best fit to the center of the spheroid is surprisingly approx 3 kpc from
the Galactic center in the direction of the Sun's motion. The model fits favor
a low value of the density of halo stars at the solar position. The alternative
to a non-axisymmetric stellar distribution is that our fits are contaminated by
previously unidentified lumpy substructure.Comment: 10 pages, 10 figs, to appear in proceedings of conference "Physics at
the end of the Galactic Cosmic Ray Spectrum", Journal of Physics: Conf.
series, eds. G. Thomson and P. Sokolsk
Introduction
Within library and information science (LIS), the study of information behavior has traditionally focused on documentary sources of information and to some degree information that is shared through interaction.1 Such an emphasis reflects the origins of the whole field in the study of the information behavior of users of libraries and other institutions that provide access to encoded forms of knowledge. Yet the centrality of embodied experience in all aspects of human life makes the relative neglect of the body in information behavior studies surprising and potentially problematic, as a number of authors have suggested (Cox, Griffin, and Hartel 2017; Lueg 2014, 2015; Lloyd 2009, 2010, 2014; Olsson, 2010, 2016). This special double issue of Library Trends on âInformation and the Bodyâ brings together researchers interested in embodied information, including in how we receive information through the senses, what the body âknows,â and the way the body is a sign that can be interpreted by others
Recombinational DNA Repair: The RecF and RecR Proteins Limit the Extension of RecA Filaments beyond Single-Strand DNA Gaps
AbstractIn the presence of both the RecF and RecR proteins, RecA filament extension from a single strand gap into adjoining duplex DNA is attenuated. RecR protein alone has no effect, and RecF protein alone has a reduced activity. The RecFR complexes bind randomly, primarily to the duplex regions of the DNA, and the extension of the RecA filament is halted at the first complex encountered. A very slow lengthening of RecA filaments observed in the presence of RecFR is virtually eliminated when RecF is replaced with an RecF mutant protein that does not hydrolyze ATP. These observations are incorporated into an expanded model for the functions of RecF, RecO, and RecR proteins in the early stages of postreplication DNA repair
Trust in Private and Common Property Experiments
We report the results from a series of experiments designed to investigate behavior in two settings that are frequently posited in the policy literature as generating different outcomes: private property and common property. The experimental settings closely parallel earlier experimental studies of the investment or trust game. The primary research question relates to the effect of the initial allocation of property rights on the level of trust that subjects will extend to others with whom they are linked. We find that assigning the initial endowments as common property of each of N pairs of a first mover and second mover leads to marginally greater cooperation or trust than when the initial endowments are fully owned by the two individual movers as their, respective, private property. SubjectsĂÂą?? decisions are also shown to be correlated with attitudes toward trust and fairness that are measured in post-experiment questionnaires.
Prepotentials for local mirror symmetry via Calabi-Yau fourfolds
In this paper, we first derive an intrinsic definition of classical triple
intersection numbers of K_S, where S is a complex toric surface, and use this
to compute the extended Picard-Fuchs system of K_S of our previous paper,
without making use of the instanton expansion. We then extend this formalism to
local fourfolds K_X, where X is a complex 3-fold. As a result, we are able to
fix the prepotential of local Calabi-Yau threefolds K_S up to polynomial terms
of degree 2. We then outline methods of extending the procedure to non
canonical bundle cases.Comment: 42 pages, 7 figures. Expanded, reorganized, and added a theoretical
background for the calculation
Shocked Quartz in Polymict Impact Breccia from the Upper Cretaceous Yallalie Impact Structure in Western Australia
Yallalie is a ~12 km diameter circular structure located ~200 km north of Perth, Australia. Previous studies have proposed that the buried structure is a complex impact crater based on geophysical data. Allochthonous breccia exposed near the structure has previously been interpreted as proximal impact ejecta; however, no diagnostic indicators of shock metamorphism have been found. Here we report multiple (27) shocked quartz grains containing planar fractures (PFs) and planar deformation features (PDFs) in the breccia. The PFs occur in up to five sets per grain, while the PDFs occur in up to four sets per grain. Universal stage measurements of all 27 shocked quartz grains confirms that the planar microstructures occur in known crystallographic orientations in quartz corresponding to shock compression from 5 to 20 GPa. Proximity to the buried structure (~4 km) and occurrence of shocked quartz indicates that the breccia represents either primary or reworked ejecta. Ejecta distribution simulated using iSALE hydrocode predicts the same distribution of shock levels at the site as those found in the breccia, which supports a primary ejecta interpretation, although local reworking cannot be excluded. The Yallalie impact event is stratigraphically constrained to have occurred in the interval from 89.8 to 83.6 Ma based on the occurrence of Coniacian clasts in the breccia and undisturbed overlying Santonian to Campanian sedimentary rocks. Yallalie is thus the first confirmed Upper Cretaceous impact structure in Australia
Challenges for Opioid Receptor Nomenclature
Recent developments in the study of the structure and function of opioid receptors raise significant challenges for the definition of individual receptor types and the development of a nomenclature that precisely describes isoforms that may subserve different functions in vivo. Presentations at the 2013 meeting of the International Narcotics Research Conference in Cairns, Australia, considered some of the new discoveries that are now unravelling the complexities of opioid receptor signalling. Variable processing of opioid receptor messenger RNAs may lead to the presence of several isoforms of the Ό receptor. Each opioid receptor type can function either as a monomer or as part of a homo- or heterodimer or higher multimer. Additionally, recent evidence points to the existence of agonist bias in the signal transduction pathways activated through Ό receptors, and to the presence of regulatory allosteric sites on the receptors. This brief review summarizes the recent discoveries that raise challenges for receptor definition and the characterization of signal transduction pathways activated by specific receptor forms. LINKED ARTICLES: This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.NHMRC 104596
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The Prevalence and Clinical Implications of Comorbid Back Pain in Shoulder Instability: A Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability Cohort Study.
Background:Understanding predictors of pain is critical, as recent literature shows that comorbid back pain is an independent risk factor for worse functional and patient-reported outcomes (PROs) as well as increased opioid dependence after total joint arthroplasty. Purpose/Hypothesis:The purpose of this study was to evaluate whether comorbid back pain would be predictive of pain or self-reported instability symptoms at the time of stabilization surgery. We hypothesized that comorbid back pain will correlate with increased pain at the time of surgery as well as with worse scores on shoulder-related PRO measures. Study Design:Cross-sectional study; Level of evidence, 3. Methods:As part of the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort, patients consented to participate in pre- and intraoperative data collection. Demographic characteristics, injury history, preoperative PRO scores, and radiologic and intraoperative findings were recorded for patients undergoing surgical shoulder stabilization. Patients were also asked, whether they had any back pain. Results:The study cohort consisted of 1001 patients (81% male; mean age, 24.1 years). Patients with comorbid back pain (158 patients; 15.8%) were significantly older (28.1 vs 23.4 years; P < .001) and were more likely to be female (25.3% vs 17.4%; P = .02) but did not differ in terms of either preoperative imaging or intraoperative findings. Patients with self-reported back pain had significantly worse preoperative pain and shoulder-related PRO scores (American Shoulder and Elbow Surgeons score, Western Ontario Shoulder Instability Index) (P < .001), more frequent depression (22.2% vs 8.3%; P < .001), poorer mental health status (worse scores for the RAND 36-Item Health Survey Mental Component Score, Iowa Quick Screen, and Personality Assessment Screener) (P < .01), and worse preoperative expectations (P < .01). Conclusion:Despite having similar physical findings, patients with comorbid back pain had more severe preoperative pain and self-reported symptoms of instability as well as more frequent depression and lower mental health scores. The combination of disproportionate shoulder pain, comorbid back pain and mental health conditions, and inferior preoperative expectations may affect not only the patient's preoperative state but also postoperative pain control and/or postoperative outcomes
Stochastic virtual tests for fiber composites
We will describe a Virtual Test system for continuous fiber composites. The virtual test draws from a new wave of advanced experiments and theory that address physical, mathematical, and engineering aspects of material definition and failure prediction. The methods go far beyond currently standard tests and conventional FEM analysis to challenge our conception of what can constitute a practicable engineering approach. Emphasis will be given to high temperature ceramic matrix composites with textile reinforcement, which have been the subject material of the National Hypersonic Science Center, Materials and Structures, a joint AFOSR/NASA program. However, thematic topics also address generic fiber composites. Development has been organized as a âpipelineâ that links the separate disciplinary efforts of groups housed in seven institutions spread across the United States. The main research steps are: high resolution three-dimensional (3D) imaging of the microstructure, statistical characterization of the microstructure, formulation of a probabilistic generator for creating virtual specimens that replicate the measured statistics, creation of a computational model for a virtual specimen that allows general representation of discrete damage events, calibration of the model using room and high temperature tests, simulation of failure, and model validation. Key new experiments include digital surface image correlation and ”m-resolution 3D computed tomography imaging of the microstructure and evolving damage, both executed at temperatures exceeding 1500°C. Conceptual advances include using both geometry and topology to characterize stochastic microstructures. Computational methods include new probabilistic algorithms for generating stochastic virtual specimens and a new Augmented Finite Element Method that yields extreme efficiency in dealing with arbitrary cracking in heterogeneous materials. The challenge of relating variance in engineering properties to stochastic microstructure in a computationally tractable manner, while retaining necessary physical details in models, will be discussed
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