1,497 research outputs found
Compatibility of neutrino DIS data and global analyses of parton distribution functions
Neutrino\antineutrino deep inelastic scattering (DIS) data provide useful
constrains for the flavor decomposition in global fits of parton distribution
functions (PDF). The smallness of the cross-sections requires the use of
nuclear targets in the experimental setup. Understanding the nuclear
corrections is, for this reason, of utmost importance for a precise
determination of the PDFs. Here, we explore the nuclear effects in the
neutrino\antineutrino-nucleon DIS by comparing the NuTeV, CDHSW, and CHORUS
cross-sections to the predictions derived from the latest parton distribution
functions and their nuclear modifications. We obtain a good description of
these data and find no apparent disagreement between the nuclear effects in
neutrino DIS and those in charged lepton DIS. These results also indicate that
further improvements in the knowledge of the nuclear PDFs could be obtained by
a more extensive use of these sets of neutrino data.Comment: 16 pages, 8 figure
A Multi-commodity network flow model for cloud service environments
Next-generation systems, such as the big data cloud, have to cope with several challenges, e.g., move of excessive amount of data at a dictated speed, and thus, require the investigation of concepts additional to security in order to ensure their orderly function. Resilience is such a concept, which when ensured by systems or networks they are able to provide and maintain an acceptable level of service in the face of various faults and challenges. In this paper, we investigate the multi-commodity flows problem, as a task within our D 2 R 2 +DR resilience strategy, and in the context of big data cloud systems. Specifically, proximal gradient optimization is proposed for determining optimal computation flows since such algorithms are highly attractive for solving big data problems. Many such problems can be formulated as the global consensus optimization ones, and can be solved in a distributed manner by the alternating direction method of multipliers (ADMM) algorithm. Numerical evaluation of the proposed model is carried out in the context of specific deployments of a situation-aware information infrastructure
Evolving antithrombotic treatment patterns for patients with newly diagnosed atrial fibrillation
Objective We studied evolving antithrombotic therapy patterns in patients with newly diagnosed non-valvular atrial fibrillation (AF) and ≥1 additional stroke risk factor between 2010 and 2015.Methods 39 670 patients were prospectively enrolled in four sequential cohorts in the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF): cohort C1 (2010–2011), n=5500; C2 (2011–2013), n=11 662; C3 (2013–2014), n=11 462; C4 (2014–2015), n=11 046. Baseline characteristics and antithrombotic therapy initiated at diagnosis were analysed by cohort.Results Baseline characteristics were similar across cohorts. Median CHA2DS2-VASc (cardiac failure, hypertension, age ≥75 (doubled), diabetes, stroke (doubled)-vascular disease, age 65–74 and sex category (female)) score was 3 in all four cohorts. From C1 to C4, the proportion of patients on anticoagulant (AC) therapy increased by almost 15% (C1 57.4%; C4 71.1%). Use of vitamin K antagonist (VKA)±antiplatelet (AP) (C1 53.2%; C4 34.0%) and AP monotherapy (C1 30.2%; C4 16.6%) declined, while use of non-VKA oral ACs (NOACs)±AP increased (C1 4.2%; C4 37.0%). Most CHA2DS2-VASc ≥2 patients received AC, and this proportion increased over time, largely driven by NOAC prescribing. NOACs were more frequently prescribed than VKAs in men, the elderly, patients of Asian ethnicity, those with dementia, or those using non-steroidal anti-inflammatory drugs, and current smokers. VKA use was more common in patients with cardiac, vascular, or renal comorbidities.Conclusions Since NOACs were introduced, there has been an increase in newly diagnosed patients with AF at risk of stroke receiving guideline-recommended therapy, predominantly driven by increased use of NOACs and reduced use of VKA±AP or AP alone.</div
Thermodynamic analysis of inverted bifurcation
We present a thermodynamic analysis of inverted bifurcation
in binary mixtures heated from below. From this analysis it
follows that an inverted bifurcation is caused by the competition
between a stabilizing effect with a long relaxation time and a
destabilizing effect with a short relaxation time. These
conditions are precisely the same as those that give rise to
overstability. This might explain why overstability and inverted
bifurcation occur in the same systems
Experience versus complication rate in third molar surgery
OBJECTIVES: The records of 1087 patients who underwent surgical removal of third molar teeth were prospectively examined to analyse the possible relationship between postoperative complications and the surgeon's experience parameter. METHOD AND MATERIALS: Seven surgeons (three specialists in surgical dentistry [specialists SD] and four oral and maxillofacial Senior House Officers [OMFS residents]) carried out the surgical procedures. For each patient, several variables were recorded including age, gender, radiographic position of extracted teeth, treating surgeon, duration of surgery and postoperative complications. RESULTS: Analysis of the data revealed some differences in the incidence of complications produced by the specialists SD and OMFS residents. The main statistically relevant differences were increase the incidences of trismus, nerve paraesthesia, alveolar osteitis and infection in the resident-treated group, while the specialist-treated group showed higher rates of post-operative bleeding. CONCLUSION: The higher rate of postoperative complications in the resident-treated group suggests that at least some of the complications might be related to surgical experience. Further work needs to compare specialists of training programmes with different years of experience, using large cross – sectional studies
Microdevices for extensional rheometry of low viscosity elastic liquids : a review
Extensional flows and the underlying stability/instability mechanisms are of extreme relevance to the efficient operation of inkjet printing, coating processes and drug delivery systems, as well as for the generation of micro droplets. The development of an extensional rheometer to characterize the extensional properties of low viscosity fluids has therefore stimulated great interest of researchers, particularly in the last decade. Microfluidics has proven to be an extraordinary working platform and different configurations of potential extensional microrheometers have been proposed. In this review, we present an overview of several successful designs, together with a critical assessment of their capabilities and limitations
Horizontal DNA transfer mechanisms of bacteria as weapons of intragenomic conflict
Horizontal DNA transfer (HDT) is a pervasive mechanism of diversification in many microbial species, but its primary evolutionary role remains controversial. Much recent research has emphasised the adaptive benefit of acquiring novel DNA, but here we argue instead that intragenomic conflict provides a coherent framework for understanding the evolutionary origins of HDT. To test this hypothesis, we developed a mathematical model of a clonally descended bacterial population undergoing HDT through transmission of mobile genetic elements (MGEs) and genetic transformation. Including the known bias of transformation toward the acquisition of shorter alleles into the model suggested it could be an effective means of counteracting the spread of MGEs. Both constitutive and transient competence for transformation were found to provide an effective defence against parasitic MGEs; transient competence could also be effective at permitting the selective spread of MGEs conferring a benefit on their host bacterium. The coordination of transient competence with cell-cell killing, observed in multiple species, was found to result in synergistic blocking of MGE transmission through releasing genomic DNA for homologous recombination while simultaneously reducing horizontal MGE spread by lowering the local cell density. To evaluate the feasibility of the functions suggested by the modelling analysis, we analysed genomic data from longitudinal sampling of individuals carrying Streptococcus pneumoniae. This revealed the frequent within-host coexistence of clonally descended cells that differed in their MGE infection status, a necessary condition for the proposed mechanism to operate. Additionally, we found multiple examples of MGEs inhibiting transformation through integrative disruption of genes encoding the competence machinery across many species, providing evidence of an ongoing "arms race." Reduced rates of transformation have also been observed in cells infected by MGEs that reduce the concentration of extracellular DNA through secretion of DNases. Simulations predicted that either mechanism of limiting transformation would benefit individual MGEs, but also that this tactic's effectiveness was limited by competition with other MGEs coinfecting the same cell. A further observed behaviour we hypothesised to reduce elimination by transformation was MGE activation when cells become competent. Our model predicted that this response was effective at counteracting transformation independently of competing MGEs. Therefore, this framework is able to explain both common properties of MGEs, and the seemingly paradoxical bacterial behaviours of transformation and cell-cell killing within clonally related populations, as the consequences of intragenomic conflict between self-replicating chromosomes and parasitic MGEs. The antagonistic nature of the different mechanisms of HDT over short timescales means their contribution to bacterial evolution is likely to be substantially greater than previously appreciated
A High-Resolution View of Genome-Wide Pneumococcal Transformation
Transformation is an important mechanism of microbial evolution through which bacteria have been observed to rapidly adapt in response to clinical interventions; examples include facilitating vaccine evasion and the development of penicillin resistance in the major respiratory pathogen Streptococcus pneumoniae. To characterise the process in detail, the genomes of 124 S. pneumoniae isolates produced through in vitro transformation were sequenced and recombination events detected. Those recombinations importing the selected marker were independent of unselected events elsewhere in the genome, the positions of which were not significantly affected by local sequence similarity between donor and recipient or mismatch repair processes. However, both types of recombinations were sometimes mosaic, with multiple non-contiguous segments originating from the same molecule of donor DNA. The lengths of the unselected events were exponentially distributed with a mean of 2.3 kb, implying that recombinations are stochastically resolved with a fixed per base probability of 4.4×10−4 bp−1. This distribution of recombination sizes, coupled with an observed under representation of large insertions within transferred sequence, suggests transformation has the potential to reduce the size of bacterial genomes, and is unlikely to act as an efficient mechanism for the uptake of accessory genomic loci
Prehospital transdermal glyceryl trinitrate in patients with ultra-acute presumed stroke (RIGHT-2): an ambulance-based, randomised, sham-controlled, blinded, phase 3 trial
Background High blood pressure is common in acute stroke and is a predictor of poor outcome; however, large trials of
lowering blood pressure have given variable results, and the management of high blood pressure in ultra-acute stroke
remains unclear. We investigated whether transdermal glyceryl trinitrate (GTN; also known as nitroglycerin), a nitric
oxide donor, might improve outcome when administered very early after stroke onset.
Methods We did a multicentre, paramedic-delivered, ambulance-based, prospective, randomised, sham-controlled,
blinded-endpoint, phase 3 trial in adults with presumed stroke within 4 h of onset, face-arm-speech-time score of 2
or 3, and systolic blood pressure 120 mm Hg or higher. Participants were randomly assigned (1:1) to receive
transdermal GTN (5 mg once daily for 4 days; the GTN group) or a similar sham dressing (the sham group) in UKbased ambulances by paramedics, with treatment continued in hospital. Paramedics were unmasked to treatment,
whereas participants were masked. The primary outcome was the 7-level modified Rankin Scale (mRS; a measure of
functional outcome) at 90 days, assessed by central telephone follow-up with masking to treatment. Analysis was
hierarchical, first in participants with a confirmed stroke or transient ischaemic attack (cohort 1), and then in all
participants who were randomly assigned (intention to treat, cohort 2) according to the statistical analysis plan. This
trial is registered with ISRCTN, number ISRCTN26986053.
Findings Between Oct 22, 2015, and May 23, 2018, 516 paramedics from eight UK ambulance services recruited
1149 participants (n=568 in the GTN group, n=581 in the sham group). The median time to randomisation was 71 min
(IQR 45–116). 597 (52%) patients had ischaemic stroke, 145 (13%) had intracerebral haemorrhage, 109 (9%) had
transient ischaemic attack, and 297 (26%) had a non-stroke mimic at the final diagnosis of the index event. In the GTN
group, participants’ systolic blood pressure was lowered by 5·8 mm Hg compared with the sham group (p<0·0001),
and diastolic blood pressure was lowered by 2·6 mm Hg (p=0·0026) at hospital admission. We found no difference in
mRS between the groups in participants with a final diagnosis of stroke or transient ischaemic stroke (cohort 1):
3 (IQR 2–5; n=420) in the GTN group versus 3 (2–5; n=408) in the sham group, adjusted common odds ratio for poor
outcome 1·25 (95% CI 0·97–1·60; p=0·083); we also found no difference in mRS between all patients (cohort 2:
3 [2–5]; n=544, in the GTN group vs 3 [2–5]; n=558, in the sham group; 1·04 [0·84–1·29]; p=0·69). We found no
difference in secondary outcomes, death (treatment-related deaths: 36 in the GTN group vs 23 in the sham group
[p=0·091]), or serious adverse events (188 in the GTN group vs 170 in the sham group [p=0·16]) between treatment
groups.
Interpretation Prehospital treatment with transdermal GTN does not seem to improve functional outcome in patients
with presumed stroke. It is feasible for UK paramedics to obtain consent and treat patients with stroke in the ultraacute prehospital setting
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