702 research outputs found
eta - eta' - glueball mixing
We have revisited glueball mixing with the pseudoscalar mesons in the MIT bag
model scheme. The calculation has been performed in the spherical cavity
approximation to the bag using two different fermion propagators, the cavity
and the free propagators. We obtain a very small probability of mixing for the
eta at the level of $0.04-0.1% and a bigger for the eta' at the level of 4-12%.
Our results differ from previous calculations in the same scheme but seem to
agree with the experimental analysis. We discuss the origin of our difference
which stems from the treatment of our time integrations.Comment: 21 pages, 7 figure
Decoherence of Einstein-Podolsky-Rosen steering
We consider two systems A and B that share Einstein-Podolsky-Rosen (EPR)
steering correlations and study how these correlations will decay, when each of
the systems are independently coupled to a reservoir. EPR steering is a
directional form of entanglement, and the measure of steering can change
depending on whether the system A is steered by B, or vice versa. First, we
examine the decay of the steering correlations of the two-mode squeezed state.
We find that if the system B is coupled to a reservoir, then the decoherence of
the steering of A by B is particularly marked, to the extent that there is a
sudden death of steering after a finite time. We find a different directional
effect, if the reservoirs are thermally excited. Second, we study the
decoherence of the steering of a Schr\"odinger cat state, modeled as the
entangled state of a spin and harmonic oscillator, when the macroscopic system
(the cat) is coupled to a reservoir
Influence of peptidylarginine deiminase type 4 genotype and shared epitope on clinical characteristics and autoantibody profile of rheumatoid arthritis.
Background: Recent evidence suggests that distinction
of subsets of rheumatoid arthritis (RA) depending on anticyclic
citrullinated peptide antibody (anti-CCP) status may
be helpful in distinguishing distinct aetiopathologies and in
predicting the course of disease. HLA-DRB1 shared
epitope (SE) and peptidylarginine deiminase type 4
(PADI4) genotype, both of which have been implicated in
anti-CCP generation, are assumed to be associated with
RA.
Objectives: To elucidate whether PADI4 affects the
clinical characteristics of RA, and whether it would
modulate the effect of anti-CCPs on clinical course. The
combined effect of SE and PADI4 on autoantibody profile
was also analysed.
Methods: 373 patients with RA were studied. SE,
padi4_94C.T, rheumatoid factor, anti-CCPs and antinuclear
antibodies (ANAs) were determined. Disease
severity was characterised by cumulative therapy
intensity classified into ordinal categories (CTI-1 to CTI-3)
and by Steinbrocker score.
Results: CTI was significantly associated with disease
duration, erosive disease, disease activity score (DAS) 28
and anti-CCPs. The association of anti-CCPs with CTI was
considerably influenced by padi4_94C.T genotype (C/C:
ORadj=0.93, padj=0.92; C/T: ORadj=2.92,
padj=0.093; T/T: ORadj=15.3, padj=0.002). Carriage of
padi4_94T exhibited a significant trend towards higher
Steinbrocker scores in univariate and multivariate
analyses. An association of padi4_94C.T with ANAs
was observed, with noteworthy differences depending on
SE status (SE2: ORadj=6.20, padj,0.04; SE+:
ORadj=0.36, padj=0.02) and significant heterogeneity
between the two SE strata (p=0.006).
Conclusions: PADI4 genotype in combination with anti-
CCPs and SE modulates clinical and serological characteristics
of RA
Delayed diagnosis of cystic fibrosis associated with R117H on a background of 7T polythymidine tract at intron 8
AbstractWe report late diagnoses of cystic fibrosis (CF) in two men aged 61 and 65 years. At the time of presentation, both patients had significant pulmonary disease. In each case two CFTR gene mutations were identified, including R117H on a background of a poly T genotype of 7T/9T. Patients with two identified CFTR mutations which include the R117H/7T anomaly should be followed up routinely as they remain susceptible to severe lung disease
Constraining the uncertainty in emissions over India with a regional air quality model evaluation
To evaluate uncertainty in the spatial distribution of air emissions over India, we compare satellite and surface observations with simulations from the U.S. Environmental Protection Agency (EPA) Community Multi-Scale Air Quality (CMAQ) model. Seasonally representative simulations were completed for January, April, July, and October 2010 at 36 km × 36 km using anthropogenic emissions from the Greenhouse Gas-Air Pollution Interaction and Synergies (GAINS) model following version 5a of the Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants project (ECLIPSE v5a). We use both tropospheric columns from the Ozone Monitoring Instrument (OMI) and surface observations from the Central Pollution Control Board (CPCB) to closely examine modeled nitrogen dioxide (NO2) biases in urban and rural regions across India. Spatial average evaluation with satellite retrievals indicate a low bias in the modeled tropospheric column (-63.3%), which reflects broad low-biases in majority non-urban regions (-70.1% in rural areas) across the sub-continent to slightly lesser low biases reflected in semi-urban areas (-44.7%), with the threshold between semi-urban and rural defined as 400 people per km2. In contrast, modeled surface NO2 concentrations exhibit a slight high bias of +15.6% when compared to surface CPCB observations predominantly located in urban areas. Conversely, in examining extremely population dense urban regions with more than 5000 people per km2 (dense-urban), we find model overestimates in both the column (+57.8) and at the surface (+131.2%) compared to observations. Based on these results, we find that existing emission fields for India may overestimate urban emissions in densely populated regions and underestimate rural emissions. However, if we rely on model evaluation with predominantly urban surface observations from the CPCB, comparisons reflect model high biases, contradictory to the knowledge gained using satellite observations. Satellites thus serve as an important emissions and model evaluation metric where surface observations are lacking, such as rural India, and support improved emissions inventory development
Sodium channels and mammalian sensory mechanotransduction
BACKGROUND: Members of the degenerin/epithelial (DEG/ENaC) sodium channel family are mechanosensors in C elegans, and Nav1.7 and Nav1.8 voltage-gated sodium channel knockout mice have major deficits in mechanosensation. β and γENaC sodium channel subunits are present with acid sensing ion channels (ASICs) in mammalian sensory neurons of the dorsal root ganglia (DRG). The extent to which epithelial or voltage-gated sodium channels are involved in transduction of mechanical stimuli is unclear.
RESULTS: Here we show that deleting β and γENaC sodium channels in sensory neurons does not result in mechanosensory behavioural deficits. We had shown previously that Nav1.7/Nav1.8 double knockout mice have major deficits in behavioural responses to noxious mechanical pressure. However, all classes of mechanically activated currents in DRG neurons are unaffected by deletion of the two sodium channels. In contrast, the ability of Nav1.7/Nav1.8 knockout DRG neurons to generate action potentials is compromised with 50% of the small diameter sensory neurons unable to respond to electrical stimulation in vitro.
CONCLUSION: Behavioural deficits in Nav1.7/Nav1.8 knockout mice reflects a failure of action potential propagation in a mechanosensitive set of sensory neurons rather than a loss of primary transduction currents. DEG/ENaC sodium channels are not mechanosensors in mouse sensory neurons
Modelling street level PM10 concentrations across Europe: source apportionment and possible futures
Despite increasing emission controls, particulate matter (PM) has remained a critical issue for European air quality in recent years. The various sources of PM, both from primary particulate emissions as well as secondary formation from precursor gases, make this a complex problem to tackle. In order to allow for credible predictions of future concentrations under policy assumptions, a modelling approach is needed that considers all chemical processes and spatial dimensions involved, from long-range transport of pollution to local emissions in street canyons. Here we describe a modelling scheme which has been implemented in the GAINS integrated assessment model to assess compliance with PM10 (PM with aerodynamic diameter <10 um) limit values at individual air quality monitoring stations reporting to the AirBase database. The modelling approach relies on a combination of bottom up modelling of emissions, simplified atmospheric chemistry and dispersion calculations, and a traffic increment calculation wherever applicable. At each monitoring station fulfilling a few data coverage criteria, measured concentrations in the base year 2009 are explained to the extent possible and then modelled for the past and future. More than 1850 monitoring stations are covered, including more than 300 traffic stations and 80% of the stations which exceeded the EU air quality limit values in 2009. As a validation, we compare modelled trends in the period 2000-2008 to observations, which are well reproduced. The modelling scheme is applied here to quantify explicitly source contributions to ambient concentrations at several critical monitoring stations, displaying the differences in spatial origin and chemical composition of urban roadside PM10 across Europe. Furthermore, we analyse the predicted evolution of PM10 concentrations in the European Union until 2030 under different policy scenarios. Significant improvements in ambient PM10 concentrations are expected assuming successful implementation of already agreed legislation; however, these will not be large enough to ensure attainment of PM10 limit values in hot spot locations such as Southern Poland and major European cities. Remaining issues are largely eliminated in a scenario applying the best available emission control technologies to the maximal technically feasible extent
Oligocarbonate Molecular Transporters: Oligomerization-Based Syntheses and Cell-Penetrating Studies
A new family of guanidinium-rich molecular transporters featuring a novel oligocarbonate backbone with 1,7-side chain spacing is described. Conjugates can be rapidly assembled irrespective of length in a one-step oligomerization strategy that can proceed with concomitant introduction of probes (or by analogy drugs). The new transporters exhibit excellent cellular entry as determined by flow cytometry and fluorescence microscopy, and the functionality of their drug delivery capabilities was confirmed by the delivery of the bioluminescent small molecule probe luciferin and turnover by its intracellular target enzyme
Rationality as the Rule of Reason
The demands of rationality are linked both to our subjective normative perspective (given that rationality is a person-level concept) and to objective reasons or favoring relations (given that rationality is non-contingently authoritative for us). In this paper, I propose a new way of reconciling the tension between these two aspects: roughly, what rationality requires of us is having the attitudes that correspond to our take on reasons in the light of our evidence, but only if it is competent. I show how this view can account for structural rationality on the assumption that intentions and beliefs as such involve competent perceptions of downstream reasons, and explore various implications of the account
Uncovering the relation between clinical reasoning and diagnostic accuracy - An analysis of learner's clinical reasoning processes in virtual patients
Background Clinical reasoning is an important topic in healthcare training, assessment, and research. Virtual patients (VPs) are a safe environment to teach, assess and perform research on clinical reasoning and diagnostic accuracy. Our aim was to explore the details of the clinical reasoning process and diagnostic accuracy of undergraduate medical students when working with VPs using a concept mapping tool. Methods Over seven months we provided access to 67 German and 30 English VPs combined with a concept mapping tool to visualize and measure the clinical reasoning process of identifying problems, differential diagnoses, recommended tests and treatment options, and composing a summary statement about a VP. A final diagnosis had to be submitted by the learners in order to conclude the VP scenario. Learners were allowed multiple attempts or could request the correct diagnosis from the system. Results We analyzed 1,393 completed concept maps from 317 learners. We found significant differences between maps with a correct final diagnosis on one or multiple attempts and maps in which learners gave up and requested the solution from the system. These maps had lower scores, fewer summary statements, and fewer problems, differential diagnoses, tests, and treatments. Conclusions The different use patterns and scores between learners who had the correct final diagnosis on one or multiple attempts and those who gave up, indicate that diagnostic accuracy in the form of a correct final diagnosis on the first attempt has to be reconsidered as a sole indicator for clinical reasoning competency. For the training, assessment, and research of clinical reasoning we suggest focusing more on the details of the process to reach a correct diagnosis, rather than whether it was made in the first attempt
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