1,166 research outputs found
Potential evapotranspiration-related uncertainty in climate change impacts on river flow: An assessment for the Mekong River basin
SummarySix MIKE SHE models of the Mekong are developed, each employing potential evapotranspiration (PET) derived using alternative methods: BlaneyâCriddle (BC), Hamon (HM), HargreavesâSamani (HS), Linacre (LN), Penman (PN) and PriestleyâTaylor (PT). Baseline (1961â1990) PET varies, with PT followed by HS providing the lowest totals, LN and BC the highest. The largest mean annual PET is over 1.5times the smallest. Independent calibration of each model results in different optimised parameter sets that mitigate differences in baseline PET. Performance of each model is âexcellentâ (monthly NSE>0.85) or âvery goodâ (NSE: 0.65â0.85). Scenarios based on seven GCMs for a 2°C increase in global mean temperature are investigated. Inter-GCM variation in precipitation change is much larger (in percentage terms by 2.5â10times) than inter-GCM differences in PET change. Precipitation changes include catchment-wide increases or decreases as well as spatially variable directions of change, whereas PET increases for all scenarios. BC and HS produce the smallest changes, LN and HM the largest. PET method does impact scenario discharges. However, GCM-related uncertainty for change in mean discharge is on average 3.5times greater than PET method-related uncertainty. Scenarios with catchment-wide precipitation increases (decreases) induce increases (decreases) in mean discharge irrespective of PET method. Magnitude of change in discharge is conditioned by PET method; larger increases or smaller declines in discharge result from methods producing the smallest PET increases. Uncertainty in the direction of change in mean discharge due to PET method occurs for scenarios with spatially variable precipitation change, although this is limited to few gauging stations and differences are relatively small. For all scenarios, PET method-related uncertainty in direction of change in high and low flows occurs, but seasonal distribution of discharge is largely unaffected. As such, whilst PET method does influence projections of discharge, variation in the precipitation climate change signal between GCMs is a much larger source of uncertainty
How to calculate dark matter direct detection exclusion limits that are consistent with gamma rays from annihilation in the Milky Way halo
Effects of Residue Background Events in Direct Dark Matter Detection Experiments on the Determination of the WIMP Mass
In the earlier work on the development of a model-independent data analysis
method for determining the mass of Weakly Interacting Massive Particles (WIMPs)
by using measured recoil energies from direct Dark Matter detection experiments
directly, it was assumed that the analyzed data sets are background-free, i.e.,
all events are WIMP signals. In this article, as a more realistic study, we
take into account a fraction of possible residue background events, which pass
all discrimination criteria and then mix with other real WIMP-induced events in
our data sets. Our simulations show that, for the determination of the WIMP
mass, the maximal acceptable fraction of residue background events in the
analyzed data sets of O(50) total events is ~20%, for background windows of the
entire experimental possible energy ranges, or in low energy ranges; while, for
background windows in relatively higher energy ranges, this maximal acceptable
fraction of residue background events can not be larger than ~10%. For a WIMP
mass of 100 GeV with 20% background events in the windows of the entire
experimental possible energy ranges, the reconstructed WIMP mass and the
1-sigma statistical uncertainty are ~97 GeV^{+61%}_{-35%} (~94
GeV^{+55%}_{-33%} for background-free data sets).Comment: 27 pages, 22 eps figures; v2: revised version for publication,
references added and update
Nottingham Prognostic Index Plus (NPI+): a modern clinical decision making tool in breast cancer
Current management of breast cancer (BC) relies on risk stratification based on well-defined clinicopathologic factors. Global gene expression profiling studies have demonstrated that BC comprises distinct molecular classes with clinical relevance. In this study, we hypothesized that molecular features of BC are a key driver of tumour behaviour and when coupled with a novel and bespoke application of established clinicopathologic prognostic variables, can predict both clinical outcome and relevant therapeutic options more accurately than existing methods. In the current study, a comprehensive panel of biomarkers with relevance to BC was applied to a large and well-characterised series of BC, using immunohistochemistry and different multivariate clustering techniques, to identify the key molecular classes. Subsequently, each class was further stratified using a set of well-defined prognostic clinicopathologic variables. These variables were combined in formulae to prognostically stratify different molecular classes, collectively known as the Nottingham Prognostic Index Plus (NPI+). NPI+ was then used to predict outcome in the different molecular classes with.Seven core molecular classes were identified using a selective panel of 10 biomarkers. Incorporation of clinicopathologic variables in a second stage analysis resulted in identification of distinct prognostic groups within each molecular class (NPI+). Outcome analysis showed that using the bespoke NPI formulae for each biological breast cancer class provides improved patient outcome stratification superior to the traditional NPI. This study provides proof-of-principle evidence for the use of NPI+ in supporting improved individualised clinical decision making
Routine measurement of serum procalcitonin allows antibiotics to be safely withheld in patients admitted to hospital with SARS-CoV-2 infection
Background. It can be a diagnostic challenge to identify COVID-19 patients without bacterial co-infection in whom antibiotics can be safely stopped. We sought to evaluate the validity of a guideline that recommends withholding antibiotics in patients with a low serum procalcitonin (PCT).
Methods. We retrospectively collected 28-day outcome data on patients admitted to Sheffield Teaching Hospitals NHS Foundation Trust, UK, between 5 March and 15 April 2020, with a positive SARS-CoV-2 polymerase chain reaction (PCR) and PCT within 48 hours of diagnosis. PCT was considered negative if â€0.25ng/ml and positive if >0.25ng/ml. Primary outcomes included antibiotic consumption, mortality, intensive care admission and length of hospital stay.
Results. 368 patients met the inclusion criteria; 218 (59%) had a negative PCT and 150 (41%) positive. At 48 hours post-diagnosis, 73 (33%) of those with a negative PCT were receiving antimicrobials compared to 126 (84%) with a positive PCT (p<0.001), with a corresponding reduction in antimicrobial usage over 28 days (median DDD of 3.0 vs 6.8 (p<0.001); median DOT 2 vs 5 days (p<0.001) between the negative and positive PCT groups.) In the negative PCT group, there were fewer deaths (62 (28%) vs. 54 (36%), (p=0.021)) and critical care admissions (19 (9%) vs. 28 (19%), (p=0.007)) than in the positive PCT group. Median length of hospital stay was 8.7 and 9 days in the negative and positive PCT groups respectively.
Conclusions. Procalcitonin is a valuable tool in the assessment of patients with SARS-CoV-2 infection, safely reducing the potential burden of unnecessary antibiotic usage
Entropy of Lovelock Black Holes
A general formula for the entropy of stationary black holes in Lovelock
gravity theories is obtained by integrating the first law of black hole
mechanics, which is derived by Hamiltonian methods. The entropy is not simply
one quarter of the surface area of the horizon, but also includes a sum of
intrinsic curvature invariants integrated over a cross section of the horizon.Comment: 15 pages, plain Latex, NSF-ITP-93-4
Acceptability of aspirin for cancer preventive therapy: a survey and qualitative study exploring the views of the UK general population
Objectives Aspirin could be offered for colorectal cancer prevention for the UK general population. To ensure the views of the general population are considered in future guidance, we explored public perceptions of aspirin for preventive therapy.
Design We conducted an online survey to investigate aspirin use, and awareness of aspirin for cancer prevention among the UK general population. We conducted semistructured interviews with a subsample of survey respondents to explore participantsâ acceptability towards aspirin for cancer preventive therapy. We analysed the interview data using reflexive thematic analysis and mapped the themes onto the Theoretical Domains Framework, and the Necessity and Concerns Framework.
Setting Online survey and remote interviews.
Participants We recruited 400 UK respondents aged 50â70 years through a market research company to the survey. We purposefully sampled, recruited and interviewed 20 survey respondents.
Results In the survey, 19.0% (76/400) of respondents were aware that aspirin can be used to prevent cancer. Among those who had previously taken aspirin, 1.9% (4/216) had taken it for cancer prevention. The interviews generated three themes: (1) perceived necessity of aspirin; (2) concerns about side effects; and (3) preferred information sources. Participants with a personal or family history of cancer were more likely to perceive aspirin as necessary for cancer prevention. Concerns about taking aspirin at higher doses and its side effects, such as gastrointestinal bleeding, were common. Many described wanting guidance and advice on aspirin to be communicated from sources perceived as trustworthy, such as healthcare professionals.
Conclusions Among the general population, those with a personal or family history of cancer may be more receptive towards taking aspirin for preventive therapy. Future policies and campaigns recommending aspirin may be of particular interest to these groups. Multiple considerations about the benefits and risks of aspirin highlight the need to support informed decisions on the medication
Fluorescent imaging using novel conjugated polymeric nanoparticles-affimer probes in complex in vitro models of colorectal cancer
We developed a carcinoembryonic antigen (CEA) conjugated polymer nanoparticle (CPN510-CEA-Af) probe to target CEA-expressing CRC cells in vitro. Its efficacy was evaluated in 2D and 3D cultures of LS174T, LoVo, and HT29 CRC cell lines. CPN510-CEA-Af produced greater fluorescent signal intensity than unconjugated particles in both 2D cells and 3D spheriods, indicating its potential as a probe for image-guided colorectal cancer surgery
Measurement of SUSY masses via cascade decays for SPS 1a
If R-parity conserving supersymmetry exists below the TeV-scale, new particles will be produced and decay in cascades at the LHC. The lightest supersymmetric particle will escape the detectors, thereby complicating the full reconstruction of the decay chains. In this paper we expand on existing methods for determining the masses of the particles in the cascade from endpoints of kinematical distributions. We perform scans in the mSUGRA parameter space to delimit the region where this method is applicable. From the examination of theoretical distributions for a wide selection of mass scenarios it is found that caution must be exerted when equating the theoretical endpoints with the experimentally obtainable ones. We provide analytic formulae for the masses in terms of the endpoints most readily available. Complications due to the composite nature of the endpoint expressions are discussed in relation to the detailed analysis of two points on the SPS 1a line. Finally we demonstrate how a Linear Collider measurement can improve dramatically on the precision of the masses obtained
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