381 research outputs found
The 2dF QSO Redshift Survey - V. The 10k catalogue
We present a catalogue comprising over 10 000 QSOs covering an effective area of 289.6 deg2, based on spectroscopic observations with the 2-degree Field (2dF) instrument at the Anglo-Australian Telescope. This catalogue forms the first release of the 2dF QSO Redshift Survey. QSO candidates with 18.2
Zanamivir susceptibility monitoring and characterization of influenza virus clinical isolates obtained during phase II clinical efficacy studies
Zanamivir is a highly selective neuraminidase (NA) inhibitor with
demonstrated clinical efficacy against influenza A and B virus infections.
In phase II clinical efficacy trials (NAIB2005 and NAIB2008), virological
substudies showed mean reductions in virus shedding after 24 h of
treatment of 1.5 to 2.0 log(10) 50% tissue culture infective doses
compared to a placebo, with no reemergence of virus after the completion
of therapy. Paired isolates (n = 41) obtained before and during therapy
with zanamivir demonstrated no shifts in susceptibility to zanamivir when
measured by NA assays, although for a few isolates NA activity was too low
to evaluate. In plaque reduction assays in MDCK cells, the susceptibility
of isolates to zanamivir was extremely variable even at baseline and did
not correlate with the speed of resolution of virus shedding. Isolates
with apparent limited susceptibility to zanamivir by plaque reduction
proved highly susceptible in vivo in the ferret model. Further sequence
analysis of paired isolates revealed no changes in the hemagglutinin and
NA genes in the majority of isolates. The few changes observed were all
natural variants. No amino acid changes that had previously been
identified in vitro as being involved with reduced susceptibility to
zanamivir were observed. These studies highlighted problems associated
with monitoring susceptibility to NA inhibitors in the clinic, in that no
reliable cell-based assay is available. At present the NA assay is the
best available predictor of susceptibility to NA inhibitors in vivo, as
measured in the validated ferret model of infection
Childhood cognitive ability accounts for associations between cognitive ability and brain cortical thickness in old age
Associations between brain cortical tissue volume and cognitive function in old age are frequently interpreted as suggesting that preservation of cortical tissue is the foundation of successful cognitive aging. However, this association could also, in part, reflect a lifelong association between cognitive ability and cortical tissue. We analyzed data on 588 subjects from the Lothian Birth Cohort 1936 who had intelligence quotient (IQ) scores from the same cognitive test available at both 11 and 70 years of age as well as high-resolution brain magnetic resonance imaging data obtained at approximately 73 years of age. Cortical thickness was estimated at 81 924 sampling points across the cortex for each subject using an automated pipeline. Multiple regression was used to assess associations between cortical thickness and the IQ measures at 11 and 70 years. Childhood IQ accounted for more than two-third of the association between IQ at 70 years and cortical thickness measured at age 73 years. This warns against ascribing a causal interpretation to the association between cognitive ability and cortical tissue in old age based on assumptions about, and exclusive reference to, the aging process and any associated disease. Without early-life measures of cognitive ability, it would have been tempting to conclude that preservation of cortical thickness in old age is a foundation for successful cognitive aging when, instead, it is a lifelong association. This being said, results should not be construed as meaning that all studies on aging require direct measures of childhood IQ, but as suggesting that proxy measures of prior cognitive function can be useful to take into consideration
Identification of cardiac MRI thresholds for risk stratification in pulmonary arterial hypertension
Rationale: Pulmonary arterial hypertension (PAH) is a life-shortening condition. The European Society of Cardiology and European Respiratory Society and the REVEAL (North American Registry to Evaluate Early and Long-Term PAH Disease Management) risk score calculator (REVEAL 2.0) identify thresholds to predict 1-year mortality.
Objectives: This study evaluates whether cardiac magnetic resonance imaging (MRI) thresholds can be identified and used to aid risk stratification and facilitate decision-making.
Methods: Consecutive patients with PAH (n = 438) undergoing cardiac MRI were identified from the ASPIRE (Assessing the Spectrum of Pulmonary Hypertension Identified at a Referral Center) MRI database. Thresholds were identified from a discovery cohort and evaluated in a test cohort.
Measurements and Main Results: A percentage-predicted right ventricular end-systolic volume index threshold of 227% or a left ventricular end-diastolic volume index of 58 ml/m2 identified patients at low (10%) risk of 1-year mortality. These metrics respectively identified 63% and 34% of patients as low risk. Right ventricular ejection fraction >54%, 37–54%, and <37% identified 21%, 43%, and 36% of patients at low, intermediate, and high risk, respectively, of 1-year mortality. At follow-up cardiac MRI, patients who improved to or were maintained in a low-risk group had a 1-year mortality <5%. Percentage-predicted right ventricular end-systolic volume index independently predicted outcome and, when used in conjunction with the REVEAL 2.0 risk score calculator or a modified French Pulmonary Hypertension Registry approach, improved risk stratification for 1-year mortality.
Conclusions: Cardiac MRI can be used to risk stratify patients with PAH using a threshold approach. Percentage-predicted right ventricular end-systolic volume index can identify a high percentage of patients at low-risk of 1-year mortality and, when used in conjunction with current risk stratification approaches, can improve risk stratification. This study supports further evaluation of cardiac MRI in risk stratification in PAH
The role of negative emotions in the social processes of entrepreneurship: Power rituals and shame-related appeasement behaviors
This paper examines the role of negative emotions in the social processes of entrepreneurship. Drawing on a study of Russian entrepreneurs, we develop a model of the emotional effects of social interactions between entrepreneurs and state officials. We found that negative emotions were elicited by these interactions and, in turn, fueled three forms of shame-related corrective appeasement behavior (reactive, anticipatory, and sporadic), which served to corrode entrepreneurial motivation and direct attention and energy away from business growth and development
Cosmological parameter estimation and the inflationary cosmology
We consider approaches to cosmological parameter estimation in the
inflationary cosmology, focussing on the required accuracy of the initial power
spectra. Parametrizing the spectra, for example by power-laws, is well suited
to testing the inflationary paradigm but will only correctly estimate
cosmological parameters if the parametrization is sufficiently accurate, and we
investigate conditions under which this is achieved both for present data and
for upcoming satellite data. If inflation is favoured, reliable estimation of
its physical parameters requires an alternative approach adopting its detailed
predictions. For slow-roll inflation, we investigate the accuracy of the
predicted spectra at first and second order in the slow-roll expansion
(presenting the complete second-order corrections for the tensors for the first
time). We find that within the presently-allowed parameter space, there are
regions where it will be necessary to include second-order corrections to reach
the accuracy requirements of MAP and Planck satellite data. We end by proposing
a data analysis pipeline appropriate for testing inflation and for cosmological
parameter estimation from high-precision data.Comment: 15 pages RevTeX file with figures incorporated. Slow-roll inflation
module for use with the CAMB program can be found at
http://astronomy.cpes.susx.ac.uk/~sleach/inflation/ This version corrects a
typo in the definition of z_S (after Eq.1) and supersedes the journal versio
Express: The incremental shuttle walk test predicts mortality in non-group 1 pulmonary hypertension: results from the ASPIRE Registry.
Pulmonary hypertension (PH) is classified into 5 groups based on disease etiology but there is only limited information on the prognostic value of exercise testing in non-Group 1 PH. In
Group 1 PH the incremental shuttle walking test (ISWT) distance has been shown to correlate with pulmonary hemodynamics and predict survival without a ceiling-effect. This study
assessed the ISWT in non-group 1 PH. Data were retrieved from the ASPIRE registry (Assessing the Spectrum of Pulmonary hypertension Identified at a REferral centre) for consecutive patients diagnosed with PH. Patients were required to have been systematically assessed as Group 2-5 PH and to have a baseline ISWT within 3 months of cardiac catheterization. Patients were stratified according to incremental shuttle walk test distance (ISWD) and ISWT distance percent predicted (ISWD%pred). 479 patients with non-Group 1 PH were identified. ISWD and ISWD%pred correlated significantly with symptoms and hemodynamic severity. ISWD and ISWD%pred predicted survival with no ceiling-effect. The test was prognostic in Groups 2, 3 and 4. ISWD and ISWD%pred and change in ISWD and
ISWD%pred at 1 year were all significant predictors of outcome. In patients with non-Group 1 PH the Incremental Shuttle Walk Test is a simple non-invasive test that is easy to perform,
is predictive of survival at baseline and follow-up, reflects change and can be used in the assessment of PH of any etiology
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
Maximal exercise testing using the incremental shuttle walking test can be used to risk stratify patients with pulmonary arterial hypertension
Rationale: Exercise capacity predicts mortality in pulmonary arterial hypertension but limited data exist on the routine use of maximal exercise testing. Objectives: This study evaluates a simple to perform maximal test, the incremental shuttle walking test, and its utility in risk stratification in pulmonary arterial hypertension (PAH). Methods: Consecutive patients with pulmonary hypertension were identified from the ASPIRE registry (2001-2018). Thresholds for levels of risk were identified at baseline, tested at follow-up and incorporation into current risk stratification approaches assessed. Results: Of 4524 treatment-naïve patients with pulmonary hypertension who underwent maximal exercise testing 1,847 patients had PAH. A step-wise reduction in one-year-mortality was seen between levels 1 (≤30m; 32% mortality) and 7 (340-420m; 1% mortality) with no mortality for levels 8-12 (≥430m) in idiopathic and connective tissue disease related PAH. Thresholds derived at baseline of ≤180m (>10%; high-risk), 190-330m (5-10%; intermediate-risk) and ≥340m (<5%; low-risk of one-year mortality) were applied at follow-up and also accurately identified levels of risk. Thresholds were incorporated into the REVEAL 2.0 risk score calculator and French low-risk approach to risk stratification and distinct categories of risk remained. Conclusion: We have demonstrated that maximal exercise testing in PAH stratifies mortality-risk at baseline and follow-up. This study highlights the potential value of the incremental shuttle walking test as an alternative to the 6-minute-walk-test, combining some of the advantages of maximal exercise testing whilst maintaining the simplicity of a simple to perform field test
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