3,383 research outputs found
Quark deconfinement in neutron star cores: The effects of spin-down
We study the role of spin-down in driving quark deconfinement in the high
density core of isolated neutron stars. Assuming spin-down to be solely due to
magnetic braking, we obtain typical timescales to quark deconfinement for
neutron stars that are born with Keplerian frequencies. Employing different
equations of state (EOS), we determine the minimum and maximum neutron star
masses that will allow for deconfinement via spin-down only. We find that the
time to reach deconfinement is strongly dependent on the magnetic field and
that this time is least for EOS that support the largest minimum mass at zero
spin, unless rotational effects on stellar structure are large. For a fiducial
critical density of for the transition to the quark phase
(g/cm is the saturation density of nuclear
matter), we find that neutron stars lighter than cannot reach a
deconfined phase. Depending on the EOS, neutron stars of more than
can enter a quark phase only if they are spinning faster than
about 3 milliseconds as observed now, whereas larger spin periods imply that
they are either already quark stars or will never become one.Comment: 4 pages, 4 figures, submitted to ApJ
Radiocarbon dates from the Oxford AMS system: archaeometry datelist 35
This is the 35th list of AMS radiocarbon determinations measured at the Oxford Radiocarbon Accelerator Unit (ORAU). Amongst some of the sites included here are the latest series of determinations from the key sites of Abydos, El Mirón, Ban Chiang, Grotte de Pigeons (Taforalt), Alepotrypa and Oberkassel, as well as others dating to the Palaeolithic, Mesolithic and later periods. Comments on the significance of the results are provided by the submitters of the material
A new approach to the chronology of caves 268/272/275 in the Dunhuang Mogao Grottoes: combining radiocarbon dates and archaeological information within a Bayesian statistical framework
The construction chronology of three of the earliest Dunhuang Mogao Grottoes (Caves 268, 272, and 275) has been the subject of ongoing debate for over half a century. This chronology is a crucial topic in terms of further understanding of the establishment of the Dunhuang Mogao Grottoes, early Buddhism in the Gansu corridor, and its relationship with Buddhism developed in the Central Plains. Building upon archaeological, art historical and radiocarbon (14C) dating studies, we integrate new 14C data with these previously published findings utilizing Bayesian statistical modeling to improve the chronological resolution of this issue. Thus, we determine that all three of these caves were constructed around AD 410–440, suggesting coeval rather than sequential construction
The Dean\u27s Letter
https://scholarship.shu.edu/law_newspapers/1007/thumbnail.jp
Tau Aggregation Inhibitor Therapy : An Exploratory Phase 2 Study in Mild or Moderate Alzheimer's Disease
ACKNOWLEDGMENTS We thank patients and their caregivers for their participation in the study and are indebted to all the investigators involved in the study, particularly Drs. Douglas Fowlie and Donald Mowat for their helpful contributions to the clinical execution of the study in Scotland. We thank Sharon Eastwood, Parexel, for assistance in preparing initial drafts of the manuscript. We acknowledge constructive comments provided by Professors G. Wilcock and S. Gauthier on drafts of the article. CMW, CRH, and JMDS are officers of, and hold beneficial interests in, TauRx Therapeutics. RTS, PB, KK, and DJW are paid consultants to TauRx Therapeutics. The study was financed entirely by TauRx TherapeuticsPeer reviewedPublisher PD
Bayesian age-depth modelling of Late Quaternary deposits from Wet and Blanche Caves, Naracoorte, South Australia: a framework for comparative faunal analyses
Bayesian age-depth models were constructed for two Late Quaternary aged fossil-bearing sedimentary sequences from caves in south eastern South Australia. The deposits in Wet and Blanche Caves contain dense assemblages of vertebrate fossils, largely the result of owl pellet accumulation. While individually calibrated radiocarbon determinations from the fossil sequences have provided a chronology for their accumulation, there was limited capacity available with such data to (a) temporally constrain assemblages associated with different depositional units and layers within the two sites, (b) interpret the chronological relationships among successive units and layers and (c) correlate sedimentary units and layers of similar age between the two deposits. Here, Bayesian age-depth models were constructed in OxCal for the Wet and Blanche Cave sequences, incorporating the available radiocarbon data and stratigraphic information collected during their excavation. Despite the low precision of the age-depth models for Wet and Blanche Caves which results in part from there being only single radiocarbon determinations available for a number of units and layers, the models enabled the relationships within and between the two sites to be established. Of particular utility for future faunal analyses is quantification of the temporal relationship between strata from the two sites, where groups of individual layers from Blanche Cave were found to be temporally equivalent with the longer-duration units in Wet Cave. We suggest that the use of Phase modelling, as performed here, is useful for cave deposits that have complex depositional histories and even in such instances where, as is common for palaeontological sites, few radiocarbon data are collected relative to the time-spans of tens of millennia that are often represented by them
Cataloging-in-Publication Data Joint Bank-Fund Library
Managing volatile capital flows: experiences and lessons for Sub-Saharan African frontier markets / prepared by Trevor Alleyne [and eight others], under the guidance of Anne-Marie Gulde-Wolf. – Washington, D.C.: International Monetary Fund, 2014. pages.; cm Includes bibliographical references. ISBN: 978-1-61635-884-
Early Life Socioeconomic Circumstance and Late Life Brain Hyperintensities : A Population Based Cohort Study
Funding: Image acquisition and image analysis for this study was funded by the Alzheimer's Research Trust (now Alzheimer's Research UK). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments The authors would like to thank the participants of the Aberdeen 1936 Birth Cohort (ABC36), without whom this research would not have been possible.Peer reviewedPublisher PD
Using Simulated Family Presence to Decrease Agitation in Older Hospitalized Delirious Patients: A Randomized Controlled Trial
Background: Simulated family presence has been shown to be an effective nonpharmacological intervention to reduce agitation in persons with dementia in nursing homes. Hyperactive or mixed delirium is a common and serious complication experienced by hospitalized patients, a key feature of which is agitation. Effective nonpharmacological interventions to manage delirium are needed.
Objectives: To examine the effect of simulated family presence through pre-recorded video messages on the agitation level of hospitalized, delirious, acutely agitated patients.
Design: Single site randomized control trial, 3 groups x 4 time points mixed factorial design conducted from July 2015 to March 2016.
Setting: Acute care level one trauma center in an inner city of the state of Connecticut, USA.
Participants: Hospitalized patients experiencing hyperactive or mixed delirium and receiving continuous observation were consecutively enrolled (n = 126), with 111 participants completing the study. Most were older, male, Caucasian, spouseless, with a pre-existing dementia.
Methods: Participants were randomized to one of the following study arms: view a one minute family video message, view a one minute nature video, or usual care. Participants in experimental groups also received usual care. The Agitated Behavior Scale was used to measure the level of agitation prior to, during, immediately following, and 30 minutes following the intervention.
Results: Both the family video and nature video groups displayed a significant change in median agitation scores over the four time periods (p \u3c .001), whereas the control group did not. The family video group had significantly lower median agitation scores during the intervention period (p \u3c .001) and a significantly greater proportion (94%) of participants experiencing a reduction in agitation from the pre-intervention to during intervention (p \u3c .001) than those viewing the nature video (70%) or those in usual care only (30%). The median agitation scores for the three groups were not significantly different at either of the post intervention time measurements. When comparing the proportion of participants experiencing a reduction in agitation from baseline to post intervention, there remained a statistically significant difference (p = .001) between family video(60%) and usual care (35.1%) immediately following the intervention
Conclusion: This work provides preliminary support for the use of family video messaging as a nonpharmacological intervention that may decrease agitation in selected hospitalized delirious patients. Further studies are necessary to determine the efficacy of the intervention as part of a multi-component intervention as well as among younger delirious patients without baseline dementia
Angiotensin II type 1 receptor antibodies in childhood kidney transplantation
Angiotensin II type 1 receptor antibodies (AT1 RAb) have emerged as non-HLA Ab present in patients with acute AMR and risk of graft loss. Furthermore, AT1 RAb have been shown to increase angiotensin II sensitivity which may play a role in the development of CVD and hypertension. Data on AT1 RAb in stable transplant recipients are lacking. The aim of this study was to analyze the levels of AT1 RAb in a cohort of stable patients after kidney transplantation (tx) in childhood. A cross-sectional study of 30 children (median age 14, range 3-19 yr, median time since tx five yr) and 28 adults who were transplanted in childhood (median age 26, range 20-40 yr, median time since tx 18 yr) transplanted between 1993-2006 and 1983-2002, respectively, was performed. Healthy controls were 51 healthy children (5-8 yr) and 199 healthy donors (median age 56.5 yr, range 42-83 yr). Plasma AT1 RAb were analyzed by immunoassay. Median total AT1 RAb IgG concentration was significantly higher in the pediatric-tx group as compared to the adult-tx group (40.0 and 10.95 U/mL, p < 0.0001). For both groups, the tx group showed higher levels: the pediatric-tx group vs. control group (40.0 vs. 13.3 U/mL, p = 0.0006) and the adult-tx group vs. adult control group (10.95 vs. 6.5 U/mL, p < 0.0001). Age was the strongest indicator of high levels of AT1 RAb IgG (p = 0.0003). AT1 RAb total IgG levels are significantly higher in a stable pediatric-tx cohort as compared to adult-tx patients and healthy controls of comparable age groups. The relevance of our findings in relation to age, time since tx, previous or future rejection, and CVD risk merits future studies
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