7,532 research outputs found
Magnetic reconnection in plasma under inertial confinement fusion conditions driven by heat flux effects in Ohm's law
In the interaction of high-power laser beams with solid density plasma there
are a number of mechanisms that generate strong magnetic fields. Such fields
subsequently inhibit or redirect electron flows, but can themselves be advected
by heat fluxes, resulting in complex interplay between thermal transport and
magnetic fields.We show that for heating by multiple laser spots reconnection
of magnetic field lines can occur, mediated by these heat fluxes, using a fully
implicit 2D Vlasov-Fokker-Planck code. Under such conditions, the reconnection
rate is dictated by heat flows rather than Alfv\`enic flows. We find that this
mechanism is only relevant in a high plasma. However, the Hall
parameter can be large so that thermal transport is
strongly modified by these magnetic fields, which can impact longer time scale
temperature homogeneity and ion dynamics in the system
The Role of Private Sector Payment Rules and a Proposed Approach for Evaluating Future Changes to Payments Law
Private sector payment organizations should continue to play the primary role in establishing rights and responsibilities for payment transactions between their participating financial institutions, provided that their rules are consistent with customer protections established by federal and state governmental authorities for the customer-financial institution relationship. Current payments law structure, relying on a combination of private sector rules, baseline statutory consumer protections, and (in the case of check payments) a somewhat variable uniform check collection statute, has shown remarkable flexibility in facilitating and responding to the unprecedented scope and pace of change that has occurred in the retail payments world over the last twenty years. The financial services industry should continue to support these two separate spheres of payment laws, private sector rules and government-mandated baseline consumer protection rules. The payment system stakeholders should not attempt to further regulate or limit, either by legislation or by regulation, the ability of private sector payment organizations to establish rules governing the relationships between their participating financial institutions
The Role of Private Sector Payment Rules and a Proposed Approach for Evaluating Future Changes to Payments Law
Private sector payment organizations should continue to play the primary role in establishing rights and responsibilities for payment transactions between their participating financial institutions, provided that their rules are consistent with customer protections established by federal and state governmental authorities for the customer-financial institution relationship. Current payments law structure, relying on a combination of private sector rules, baseline statutory consumer protections, and (in the case of check payments) a somewhat variable uniform check collection statute, has shown remarkable flexibility in facilitating and responding to the unprecedented scope and pace of change that has occurred in the retail payments world over the last twenty years. The financial services industry should continue to support these two separate spheres of payment laws, private sector rules and government-mandated baseline consumer protection rules. The payment system stakeholders should not attempt to further regulate or limit, either by legislation or by regulation, the ability of private sector payment organizations to establish rules governing the relationships between their participating financial institutions
Physicians' values and their career stage
Professional values of 241 practicing physicians were determined from factor analyzing their responses to 25 questionnaire items dealing with an ideal medical school in their vicinity. The seven factors (values)--(1) Academic, (2) Professional Separatism, (3) Support, (4) Social Welfare, (5) Research/Specialization, (6) Status/ Prestige, and (7) Convenience--were examined for their relationship to background characteristics (e.g., training) and practice (e.g., specialty). Few differences were found. However, when values were analyzed by age and career stage, significant fluctuations were found. Levinson's adult development theory was able to account for a sizeable portion of the observed variations. Practical and theoretical consequences are discussed in connection with physician stress at critical career stages.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25255/1/0000698.pd
Origin, maintenance and spread of antibiotic resistance genes within plasmids and chromosomes of bloodstream isolates of Escherichia coli
The work was funded by the Scottish Executive via the Chief Scientists Office through the provision of a grant to establish the Scottish Healthcare Associated Infection Prevention Institute (SHAIPI).Blood stream invasion by Escherichia coli is the commonest cause of bacteremia in the UK and elsewhere with an attributable mortality of about 15–20 %; antibiotic resistance to multiple agents is common in this microbe and is associated with worse outcomes. Genes conferring antimicrobial resistance, and their frequent location on horizontally transferred genetic elements is well-recognised, but the origin of these determinants, and their ability to be maintained and spread within clinically-relevant bacterial populations is unclear. Here, we set out to examine the distribution of antimicrobial resistance genes in chromosomes and plasmids of 16 bloodstream isolates of E. coli from patients within Scotland, and how these genes are maintained and spread. Using a combination of short and long-read whole genome sequencing methods, we were able to assemble complete sequences of 44 plasmids, with 16 Inc group F and 20 col plasmids; antibiotic resistance genes located almost exclusively within the F group. blaCTX-M15 genes had re-arranged in some strains into the chromosome alone (five strains), while others contained plasmid copies alone (two strains). Integrons containing multiple antibiotic genes were widespread in plasmids, notably many with a dfrA7 gene encoding resistance to trimethoprim, thus linking trimethoprim resistance to the other antibiotic resistance genes within the plasmids. This will allow even narrow spectrum antibiotics such as trimethoprim to act as a selective agent for plasmids containing antibiotic resistance genes mediating much broader resistance, including blaCTX-M15. To our knowledge, this is the first analysis to provide complete sequence data of chromosomes and plasmids in a collection of pathogenic human bloodstream isolates of E. coli. Our findings reveal the interplay between plasmids and integrative and conjugative elements in the maintenance and spread of antibiotic resistance genes within pathogenic E. coli.Publisher PDFPeer reviewe
SN 2017ein and the Possible First Identification of a Type Ic Supernova Progenitor
We have identified a progenitor candidate in archival Hubble Space Telescope
(HST) images for the Type Ic SN 2017ein in NGC 3938, pinpointing the
candidate's location via HST Target-of-Opportunity imaging of the SN itself.
This would be the first identification of a stellar-like object as a progenitor
candidate for any Type Ic supernova to date. We also present observations of SN
2017ein during the first ~49 days since explosion. We find that SN 2017ein most
resembles the well-studied Type Ic SN 2007gr. We infer that SN 2017ein
experienced a total visual extinction of A_V~1.0--1.9 mag, predominantly
because of dust within the host galaxy. Although the distance is not well
known, if this object is the progenitor, it was likely of high initial mass,
~47--48 M_sun if a single star, or ~60--80 M_sun if in a binary system.
However, we also find that the progenitor candidate could be a very blue and
young compact cluster, further implying a very massive (>65 M_sun) progenitor.
Furthermore, the actual progenitor might not be associated with the candidate
at all and could be far less massive. From the immediate stellar environment,
we find possible evidence for three different populations; if the SN progenitor
was a member of the youngest population, this would be consistent with an
initial mass of ~57 M_sun. After it has faded, the SN should be reobserved at
high spatial resolution and sensitivity, to determine whether the candidate is
indeed the progenitor.Comment: Revised, following referee's comments, and accepted to ApJ; 21 pages,
10 figure
Cost-effectiveness of rosuvastatin in comparison with generic atorvastatin and simvastatin in a Swedish population at high risk of cardiovascular events
Background: To assess the long-term cost-effectiveness of rosuvastatin therapy compared with generic simvastatin and generic atorvastatin in reducing the incidence of cardiovascular events and mortality in a Swedish population with Framingham risk ≥20%. Methods: A probabilistic Monte Carlo simulation model based on data from JUPITER (the Justification for the Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin) was used to estimate the long-term cost-effectiveness of rosuvastatin 20 mg daily versus simvastatin or atorvastatin 40 mg for the prevention of cardiovascular death and morbidity. The three-stage model included cardiovascular event prevention simulating the 4 years of JUPITER, initial prevention beyond the trial, and subsequent cardiovascular event prevention. A Swedish health care payer perspective (direct costs only) was modeled for a lifetime horizon, with 2008/2009 as the costing period. Univariate and probabilistic sensitivity analyses were performed. Results: The incremental cost per quality-adjusted life-year (QALY) gained with rosuvastatin 20 mg over simvastatin or atorvastatin 40 mg ranged from SEK88,113 (rosuvastatin 20 mg versus simvastatin 40 mg; Framingham risk ≥30%; net avoidance of 34 events/1000 patients) to SEK497,542 (versus atorvastatin 40 mg: Framingham risk ≥20%; net avoidance of 11 events/1000 patients) over a lifetime horizon. Probabilistic sensitivity analyses indicated that at a willingness-to-pay threshold of SEK500,000/QALY, rosuvastatin 20 mg would be cost-effective for approximately 75%–85% of simulations relative to atorvastatin or simvastatin 40 mg. Sensitivity analyses indicated the findings to be robust. Conclusion: Rosuvastatin 20 mg is cost-effective over a lifetime horizon compared with generic simvastatin or atorvastatin 40 mg in patients at high cardiovascular risk in Sweden
Identification of the Origin of Monojet Signatures at the LHC
Several new physics scenarios can lead to monojet signatures at the LHC. If
such events are observed above the Standard Model background it will be
important to identify their origin. In this paper we compare and contrast these
signatures as produced in two very different pictures: vector or scalar
unparticle production in the scale-invariant/conformal regime and graviton
emission in the Arkani-Hamed, Dimopoulos and Dvali extra-dimensional model. We
demonstrate that these two scenarios can be distinguished at the LHC for a
reasonable range of model parameters through the shape of their respective
monojet and/or missing distributions.Comment: 17 pages, 6 figs; figure and discussions adde
Osteomyelitis of the ribs in children: a rare and potentially challenging diagnosis
Background
Rib osteomyelitis is rare in children and can mimic other pathologies. Imaging has a major role in the diagnosing rib osteomyelitis.
Objective
To evaluate clinical presentation and imaging findings in children with rib osteomyelitis.
Materials and methods
We performed a retrospective (2009–2018) study on children with rib osteomyelitis verified by either positive culture or pathology. We excluded children with multifocal osteomyelitis or empyema necessitans. We reviewed medical charts for clinical, laboratory and pathology data, and treatment. All imaging modalities for rib abnormalities were evaluated for presence and location of osteomyelitis and abscess. We calculated descriptive statistics to compare patient demographics, clinical presentation and imaging findings.
Results
The study group included 10 children (6 boys, 4 girls), with an average age of 7.3 years (range, 3 months to 15.9 years). The most common clinical presentations were fever (n=8) and pain (n=5). Eight children had elevated inflammatory indices (leukocytosis, erythrocyte sedimentation rate [ESR], C-reactive protein [CRP]). Localized chest wall swelling was found initially in six children and later in two more children. Rib osteomyelitis was suspected on presentation in only two children. All children had chest radiographs. Rib lytic changes were found on only one chest radiograph, in two of the four ultrasound studies, and in four of eight CTs. Bone marrow signal abnormalities were seen in all eight MRIs. In nine children the osteomyelitis involved the costochondral junction. Six children had an associated abscess. Staphylococcus aureus was cultured in eight children. Osteomyelitis was diagnosed based on pathology in one child with negative cultures.
Conclusion
While rib osteomyelitis is rare, imaging findings of lytic changes at the costochondral junction combined with a history of fever, elevated inflammatory markers or localized soft-tissue swelling in the chest should raise suspicion for this disease
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