223 research outputs found
Shelfbreak frontal structure and processes north of Cape Hatteras in winter
Author Posting. © Sears Foundation for Marine Research, 2008. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 66 (2008): 755-799.The circulation north of Cape Hatteras is complicated by the proximity of the shelfbreak front, the Gulf Stream, and convergent shelf flow from the Middle and South Atlantic Bights. A three-week cruise in this region in January/February, 2005 was undertaken in order to study the structure of the shelfbreak front as it terminates near Cape Hatteras and to quantify the freshwater transport from the Middle Atlantic Bight shelf into the Gulf Stream. Two strongly contrasting conditions were identified. Early in the cruise, the Gulf Stream directly abutted the shelfbreak at Cape Hatteras and drove a northward flow over the continental shelf as far north as 35°45′N. All of the Middle Atlantic Bight shelf water terminated by 35°30′N. Ten days later, the Gulf Stream had moved away from the shelfbreak south of Cape Hatteras and strong winds from the north were present. During this time, the shelfbreak frontal jet was strong (maximum southward velocity of approximately 0.5 m s-1 with a Rossby number of 2) and abruptly turned eastward and offshore between 35°35′N and 35°45′N. Freshwater transport eastward from the shelfbreak jet was 7.4 mSv and southward over the shelf was 19.9 mSv, giving a total freshwater transport of 27.3 mSv. This likely represents an upper bound due to the strong wind forcing. Implications of these results for the freshwater budget of the Middle Atlantic Bight shelf, stability properties of the shelfbreak front in this region, and the formation of “Ford water” in the Gulf Stream are discussed.Support for the Rutgers satellite archive is provided by NSF, ONR and NOAA.
This work was supported under NSF Grant Number OCE-0327249
The current global situation for tuberculous meningitis : epidemiology, diagnostics, treatment and outcomes [version 1; peer review: 2 approved]
CITATION: Seddon, J., et al. 2019. The current global situation for tuberculous meningitis : epidemiology, diagnostics, treatment and outcomes [version 1; peer review: 2 approved]. Wellcome Open Research, 4:167, doi:10.12688/wellcomeopenres.15535.1.The original publication is available at https://wellcomeopenresearch.orgTuberculous meningitis (TBM) results from dissemination of M. tuberculosis to the cerebrospinal fluid (CSF) and meninges. Ischaemia, hydrocephalus and raised intracranial pressure frequently result, leading to extensive brain injury and neurodisability. The global burden of TBM is unclear and it is likely that many cases are undiagnosed, with many treated cases unreported. Untreated, TBM is uniformly fatal, and even if treated, mortality and morbidity are high. Young age and human immunodeficiency virus (HIV) infection are potent risk factors for TBM, while Bacillus Calmette–Guérin (BCG) vaccination is protective, particularly in young children. Diagnosis of TBM usually relies on characteristic clinical symptoms and signs, together with consistent neuroimaging and CSF parameters. The ability to confirm the TBM diagnosis via CSF isolation of M. tuberculosis depends on the type of diagnostic tests available. In most cases, the diagnosis remains unconfirmed. GeneXpert MTB/RIF and the next generation Xpert Ultra offer improved sensitivity and rapid turnaround times, and while roll-out has scaled up, availability remains limited. Many locations rely only on acid fast bacilli smear, which is insensitive. Treatment regimens for TBM are based on evidence for pulmonary tuberculosis treatment, with little consideration to CSF penetration or mode of drug action required. The World Health Organization recommends a 12-month treatment course, although data on which to base this duration is lacking. New treatment regimens and drug dosages are under evaluation, with much higher dosages of rifampicin and the inclusion of fluoroquinolones and linezolid identified as promising innovations. The inclusion of corticosteroids at the start of treatment has been demonstrated to reduce mortality in HIV-negative individuals but whether they are universally beneficial is unclear. Other host-directed therapies show promise but evidence for widespread use is lacking. Finally, the management of TBM within health systems is sub-optimal, with drop-offs at every stage in the care cascade.https://wellcomeopenresearch.org/articles/4-167Publisher's versio
Effect of Implementing Discharge Readiness Assessment in Adult Medical-Surgical Units on 30-Day Return to Hospital The READI Randomized Clinical Trial
Importance: The downward trend in readmissions has recently slowed. New enhancements to hospital readmission reduction efforts are needed. Structured assessment of patient readiness for discharge has been recommended as an addition to discharge preparation standards of care to assist with tailoring of risk-mitigating actions.
Objective: To determine the effect of unit-based implementation of readiness evaluation and discharge intervention protocols on readmissions and emergency department or observation visits.
Design, Setting, and Participants: The Readiness Evaluation and Discharge Interventions (READI) cluster randomized clinical trial conducted in medical-surgical units of 33 Magnet hospitals between September 15, 2014, and March 31, 2017, included all adult (aged ≥18 years) patients discharged to home. Baseline and risk-adjusted intent-to-treat analyses used difference-in-differences multilevel logistic regression models with controls for patient characteristics.
Interventions: Of 2 adult medical-surgical nursing units from each hospital, 1 was randomized to the intervention and 1 to usual care conditions. Using the 8-item Readiness for Hospital Discharge Scale, the 33 intervention units implemented a sequence of protocols with increasing numbers of components: READI1, in which nurses assessed patients to inform discharge preparation; READI2, which added patient self-assessment; and READI3, which added an instruction to act on a specified Readiness for Hospital Discharge Scale cutoff score indicative of low readiness.
Main Outcomes and Measures: Thirty-day return to hospital (readmission or emergency department and observation visits). Intervention units above median baseline readmission rate (\u3e11.3%) were categorized as high-readmission units. Among the 33 intervention units, 17 were low-readmission units and 16 were high-readmission units.
Results: The sample included 144 868 patient discharges (mean [SD] age, 59.6 [17.5] years; 51% female; 74 605 in the intervention group and 70 263 in the control group); 17 667 (12.2%) were readmitted and 12 732 (8.8%) had an emergency department visit or observation stay. None of the READI protocols reduced the primary outcome of return to hospital in intent-to-treat analysis of the full sample. In exploratory subgroup analysis, when patient self-assessments were combined with readiness assessment by nurses (READI2), readmissions were reduced by 1.79 percentage points (95% CI, −3.20 to −0.40 percentage points; P = .009) on high-readmission units. With nurse assessment alone and on low-readmission units, results were mixed.
Conclusions and Relevance: Implemented in a broad range of hospitals and patients, the READI interventions were not effective in reducing return to hospital. However, adding a structured discharge readiness assessment that incorporates the patient’s own perspective to usual discharge care practices holds promise for mitigating high rates of return to the hospital following discharge
Charge asymmetry ratio as a probe of quark flavour couplings of resonant particles at the LHC
We show how a precise knowledge of parton distribution functions, in
particular those of the u and d quarks, can be used to constrain a certain
class of New Physics models in which new heavy charged resonances couple to
quarks and leptons. We illustrate the method by considering a left-right
symmetric model with a W' from a SU(2)_R gauge sector produced in
quark-antiquark annihilation and decaying into a charged lepton and a heavy
Majorana neutrino. We discuss a number of quark and lepton mixing scenarios,
and simulate both signals and backgrounds in order to determine the size of the
expected charge asymmetry. We show that various quark-W' mixing scenarios can
indeed be constrained by charge asymmetry measurements at the LHC, particularly
at 14 TeV centre of mass energy.Comment: 14 pages, 3 figure
Phase space descriptions for simplicial 4d geometries
Starting from the canonical phase space for discretised (4d) BF-theory, we
implement a canonical version of the simplicity constraints and construct phase
spaces for simplicial geometries. Our construction allows us to study the
connection between different versions of Regge calculus and approaches using
connection variables, such as loop quantum gravity. We find that on a fixed
triangulation the (gauge invariant) phase space associated to loop quantum
gravity is genuinely larger than the one for length and even area Regge
calculus. Rather, it corresponds to the phase space of area-angle Regge
calculus, as defined by Dittrich and Speziale in [arXiv:0802.0864] (prior to
the imposition of gluing constraints, that ensure the metricity of the
triangulation). We argue that this is due to the fact that the simplicity
constraints are not fully implemented in canonical loop quantum gravity.
Finally, we show that for a subclass of triangulations one can construct first
class Hamiltonian and Diffeomorphism constraints leading to flat 4d
space-times.Comment: corrected structure constants, several references ad
Machine Learning Automated Detection of Large Vessel Occlusion From Mobile Stroke Unit Computed Tomography Angiography
BACKGROUND: Prehospital automated large vessel occlusion (LVO) detection in Mobile Stroke Units (MSUs) could accelerate identification and treatment of patients with LVO acute ischemic stroke. Here, we evaluate the performance of a machine learning (ML) model on CT angiograms (CTAs) obtained from 2 MSUs to detect LVO.
METHODS: Patients evaluated on MSUs in Houston and Los Angeles with out-of-hospital CTAs were identified. Anterior circulation LVO was defined as an occlusion of the intracranial internal carotid artery, middle cerebral artery (M1 or M2), or anterior cerebral artery vessels and determined by an expert human reader. A ML model to detect LVO was trained and tested on independent data sets consisting of in-hospital CTAs and then tested on MSU CTA images. Model performance was determined using area under the receiver-operator curve statistics.
RESULTS: Among 68 patients with out-of-hospital MSU CTAs, 40% had an LVO. The most common occlusion location was the middle cerebral artery M1 segment (59%), followed by the internal carotid artery (30%), and middle cerebral artery M2 (11%). Median time from last known well to CTA imaging was 88.0 (interquartile range, 59.5-196.0) minutes. After training on 870 in-hospital CTAs, the ML model performed well in identifying LVO in a separate in-hospital data set of 441 images with area under receiver-operator curve of 0.84 (95% CI, 0.80-0.87). ML algorithm analysis time was under 1 minute. The performance of the ML model on the MSU CTA images was comparable with area under receiver-operator curve 0.80 (95% CI, 0.71-0.89). There was no significant difference in performance between the Houston and Los Angeles MSU CTA cohorts.
CONCLUSIONS: In this study of patients evaluated on MSUs in 2 cities, a ML algorithm was able to accurately and rapidly detect LVO using prehospital CTA acquisitions
Monitoring of the operating parameters of the KATRIN Windowless Gaseous Tritium Source
The Karlsruhe Tritium Neutrino (KATRIN) experiment will measure the absolute
mass scale of neutrinos with a sensitivity of \m_{\nu} = 200 meV/c by
high-precision spectroscopy close to the tritium beta-decay endpoint at 18.6
keV. Its Windowless Gaseous Tritium Source (WGTS) is a beta-decay source of
high intensity (/s) and stability, where high-purity molecular tritium
at 30 K is circulated in a closed loop with a yearly throughput of 10 kg. To
limit systematic effects the column density of the source has to be stabilised
at the 0.1% level. This requires extensive sensor instrumentation and dedicated
control and monitoring systems for parameters such as the beam tube
temperature, injection pressure, gas composition and others. Here we give an
overview of these systems including a dedicated Laser-Raman system as well as
several beta-decay activity monitors. We also report on results of the WGTS
demonstrator and other large-scale test experiments giving proof-of-principle
that all parameters relevant to the systematics can be controlled and monitored
on the 0.1% level or better. As a result of these works, the WGTS systematics
can be controlled within stringent margins, enabling the KATRIN experiment to
explore the neutrino mass scale with the design sensitivity.Comment: 32 pages, 13 figures. modification to title, typos correcte
Acoustics and oceanographic observations collected during the QPE Experiment by Research Vessels OR1, OR2 and OR3 in the East China Sea in the Summer of 2009
This document describes data, sensors, and other useful information pertaining to the ONR sponsored
QPE field program to quantify, predict and exploit uncertainty in observations and prediction of sound
propagation. This experiment was a joint operation between Taiwanese and U.S. researchers to
measure and assess uncertainty of predictions of acoustic transmission loss and ambient noise, and to
observe the physical oceanography and geology that are necessary to improve their predictability. This
work was performed over the continental shelf and slope northeast of Taiwan at two sites: one that was
a relatively flat, homogeneous shelf region and a more complex geological site just shoreward of the
shelfbreak that was influenced by the proximity of the Kuroshio Current. Environmental moorings
and ADCP moorings were deployed and a shipboard SeaSoar vehicle was used to measure
environmental spatial structure. In addition, multiple bottom moored receivers and a horizontal
hydrophone array were deployed to sample transmission loss from a mobile source and ambient noise.
The acoustic sensors, environmental sensors, shipboard resources, and experiment design, and their
data, are presented and described in this technical report.Funding was provided by the Office of Naval Research under Contract No. N00014-08-1-076
Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector
The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry
Cadherin 2-Related Arrhythmogenic Cardiomyopathy Prevalence and Clinical Features
Background:Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiac disease characterized by fibrofatty replacement of the right and left ventricle, often causing ventricular dysfunction and life-threatening arrhythmias. Variants in desmosomal genes account for up to 60% of cases. Our objective was to establish the prevalence and clinical features of ACM stemming from pathogenic variants in the nondesmosomal cadherin 2 (CDH2), a novel genetic substrate of ACM.Methods:A cohort of 500 unrelated patients with a definite diagnosis of ACM and no disease-causing variants in the main ACM genes was assembled. Genetic screening of CDH2 was performed through next-generation or Sanger sequencing. Whenever possible, cascade screening was initiated in the families of CDH2-positive probands, and clinical evaluation was performed.Results:Genetic screening of CDH2 led to the identification of 7 rare variants: 5, identified in 6 probands, were classified as pathogenic or likely pathogenic. The previously established p.D407N pathogenic variant was detected in 2 additional probands. Probands and family members with pathogenic/likely pathogenic variants in CDH2 were clinically evaluated, and along with previously published cases, altogether contributed to the identification of gene-specific features (13 cases from this cohort and 11 previously published, for a total of 9 probands and 15 family members). Ventricular arrhythmic events occurred in most CDH2-positive subjects (20/24, 83%), while the occurrence of heart failure was rare (2/24, 8.3%). Among probands, sustained ventricular tachycardia and sudden cardiac death occurred in 5/9 (56%).Conclusions:In this worldwide cohort of previously genotype-negative ACM patients, the prevalence of probands with CDH2 pathogenic/likely pathogenic variants was 1.2% (6/500). Our data show that this cohort of CDH2-ACM patients has a high incidence of ventricular arrhythmias, while evolution toward heart failure is rare.</p
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