603 research outputs found
Covariant derivative of the curvature tensor of pseudo-K\"ahlerian manifolds
It is well known that the curvature tensor of a pseudo-Riemannian manifold
can be decomposed with respect to the pseudo-orthogonal group into the sum of
the Weyl conformal curvature tensor, the traceless part of the Ricci tensor and
of the scalar curvature. A similar decomposition with respect to the
pseudo-unitary group exists on a pseudo-K\"ahlerian manifold; instead of the
Weyl tensor one obtains the Bochner tensor. In the present paper, the known
decomposition with respect to the pseudo-orthogonal group of the covariant
derivative of the curvature tensor of a pseudo-Riemannian manifold is refined.
A decomposition with respect to the pseudo-unitary group of the covariant
derivative of the curvature tensor for pseudo-K\"ahlerian manifolds is
obtained. This defines natural classes of spaces generalizing locally symmetric
spaces and Einstein spaces. It is shown that the values of the covariant
derivative of the curvature tensor for a non-locally symmetric
pseudo-Riemannian manifold with an irreducible connected holonomy group
different from the pseudo-orthogonal and pseudo-unitary groups belong to an
irreducible module of the holonomy group.Comment: the final version accepted to Annals of Global Analysis and Geometr
Expanding the Roles of Libraries: A Review of Institutional Repository in Promoting and Preserving Academic Research
Institutional repository is a new scholarly publishing model for researchers and academic institutions. The idea is conceived to enable broader access and dissemination of knowledge as well as preservation for future use, which are the core roles of traditional libraries. However, digital technology facilitates the adoption of institutional repository and makes libraries responsible for its management. Thus, libraries have reclaimed their function of preserving knowledge which has hitherto been hindered by digital right management policies whose emphasis is on access rather than ownership, and which has prohibited libraries from claiming ownership of subscribed materials. Institutional repository roles in enhancing academic research, faculty-librarian collaboration, library services and collections, as well as the roles of libraries in promoting and preserving academic research knowledge for posterity cannot be undermined. To achieve these laudable roles, preservation policy for repositories is of paramount importance. The study thus provides a review of different literatures to explore the key roles of institutional repositories in promoting academic research. The review of literature revealed that lack of adoption of repository policies pose challenges to institutional repositories in the preservation of academic research. The analysis of the Registry of Open Access Repository Mandates and Policies (ROARMAP) statistics showed a partial adoption of repository policies among research institutions. It is recommended that adoption of preservation policies for repository content should spread across borders and form prerequisite for establishing institutional repositories. This review suggested other factors to consider in improving the implementation of institutional repository policies towards preserving academic research
Matrix metalloproteinase-9 predicts pulmonary status declines in α1-antitrypsin deficiency
<p>Abstract</p> <p>Background</p> <p>Matrix metalloproteinase-9 (MMP-9) may be important in the progression of emphysema, but there have been few longitudinal clinical studies of MMP-9 including pulmonary status and COPD exacerbation outcomes.</p> <p>Methods</p> <p>We utilized data from the placebo arm (n = 126) of a clinical trial of patients with alpha<sub>1</sub>-antitrypsin deficiency (AATD) and emphysema to examine the links between plasma MMP-9 levels, pulmonary status, and COPD exacerbations over a one year observation period. Pulmonary function, computed tomography lung density, incremental shuttle walk test (ISWT), and COPD exacerbations were assessed at regular intervals over 12 months. Prospective analyses used generalized estimating equations to incorporate repeated longitudinal measurements of MMP-9 and all endpoints, controlling for age, gender, race-ethnicity, leukocyte count, and tobacco history. A secondary analysis also incorporated highly-sensitive C-reactive protein levels in predictive models.</p> <p>Results</p> <p>At baseline, higher plasma MMP-9 levels were cross-sectionally associated with lower FEV<sub>1 </sub>(p = 0.03), FVC (p < 0.001), carbon monoxide transfer factor (p = 0.03), resting oxygen saturation (p = 0.02), and ISWT distance walked (p = 0.02) but were not associated with radiographic lung density or total lung capacity (TLC). In longitudinal analyses, MMP-9 predicted a further decline in transfer factor (p = 0.04) and oxygen saturation (p < 0.001). MMP-9 also predicted worsening lung density (p = 0.003), increasing TLC (p = 0.02), and more frequent COPD exacerbations over follow-up (p = 0.003). Controlling additionally for hs-CRP levels did not substantively change the longitudinal associations between MMP-9 and these outcomes.</p> <p>Conclusions</p> <p>Increased plasma MMP-9 levels generally predicted pulmonary status declines, including worsening transfer factor and lung density as well as greater COPD exacerbations in AATD-associated emphysema.</p
Synthesis and Antifungal Activity of Some Organotin(IV) Carboxylates
Six diorganotin(IV) carboxylates prepared by reacting diorganotin(IV) dichlorides with the
respective silver carboxylate have been tested for antifungal activity against Aspergillus. niger, Aspergilluus flavus and Pencillium. citrinum in Sabourand dextrose broth. The compounds
generally exhibit greater fungitoxicity than the diorganotin(IV) dichlorides and the carboxylic acids
from which they were synthesized. In keeping with the generally accepted notion that the
organotin moiety plays an important role in deciding the antifungal activity of an organotin
compound, the diphenyltin(IV) compounds were more active than their di-n-butyltin(IV) analogues.
However, the order of increasing fungitoxicity of the compounds parallels that of the uncomplexed
carboxylic acids. The implications of the results are discussed
Cardiovascular and cerebrovascular events among patients receiving omalizumab: Results from EXCELS, a prospective cohort study in moderate to severe asthma
BackgroundEXCELS, a postmarketing observational cohort study, was a commitment to the US Food and Drug Administration to assess the long-term safety of omalizumab in an observational setting, focusing predominantly on malignancies.ObjectiveThe aim of this study was to examine a potential association between omalizumab and cardiovascular (CV)/cerebrovascular (CBV) events in EXCELS.MethodsPatients (≥12 years of age) with moderate to severe allergic asthma and who were being treated with omalizumab (n = 5007) or not (n = 2829) at baseline were followed up for ≤5 years. Analyses included overall CV/CBV events, but focused on the subset of arterial thromboembolic events (ATEs), comprising CV death, myocardial infarction, ischemic stroke, transient ischemic attack, and unstable angina. A prespecified analysis of the end point of ATE was conducted to control for available potential confounders. A blinded independent expert panel adjudicated all events.ResultsAt baseline, the 2 cohorts had similar demographic characteristics, but severe asthma was more common in the omalizumab versus the non-omalizumab group (50% vs 23%). Omalizumab-treated patients had a higher rate of CV/CBV serious adverse events (13.4 per 1,000 person years [PYs]) than did non–omalizumab-treated patients (8.1 per 1,000 PYs). The ATE rates per 1,000 PYs were 6.66 (101 patients/15,160 PYs) in the omalizumab cohort and 4.64 (46 patients/9,904 PYs) in the non-omalizumab cohort. After control for available confounding factors, the hazard ratio was 1.32 (95% CI, 0.91-1.91).ConclusionThis observational study demonstrated a higher incidence rate of CV/CBV events in the omalizumab versus the non-omalizumab cohort. Differences in asthma severity between cohorts likely contributed to this imbalance, but some increase in risk cannot be excluded
Efficacy and safety of omalizumab in nasal polyposis : 2 randomized phase 3 trials
Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by IgE hyperproduction and eosinophilic inflammation. The anti-IgE antibody, omalizumab, has demonstrated efficacy in patients with CRSwNP and comorbid asthma previously. Objective: Our aim was to determine omalizumab safety and efficacy in CRSwNP in phase 3 trials (POLYP 1 and POLYP 2). Methods: Adults with CRSwNP with inadequate response to intranasal corticosteroids were randomized (1:1) to omalizumab or placebo and intranasal mometasone for 24 weeks. Coprimary end points included change from baseline to week 24 in Nasal Polyp Score (NPS) and Nasal Congestion Score. Secondary end points included change from baseline to week 24 in Sino-Nasal Outcome Test-22 (SNOT-22) score, University of Pennsylvania Smell Identification Test, sense of smell, postnasal drip, runny nose, and adverse events. Results: Patients in POLYP 1 (n = 138) and POLYP 2 (n = 127) exhibited severe CRSwNP and substantial quality of life impairment evidenced by a mean NPS higher than 6 and SNOT-22 score of approximately 60. Both studies met both the coprimary end points. SNOT-22 score, University of Pennsylvania Smell Identification Test score, sense of smell, postnasal drip, and runny nose were also significantly improved for omalizumab versus placebo. In POLYP 1 and POLYP 2, the mean changes from baseline at week 24 for omalizumab versus placebo were as follows: NPS, -1.08 versus 0.06 (P < .0001) and - 0.90 versus -0.31 (P = .0140); Nasal Congestion Score, -0.89 versus -0.35 (P = .0004) and -0.70 versus -0.20 (P = .0017); and SNOT-22 score, -24.7 versus -8.6 (P < .0001) and -21.6 versus - 6.6 (P < .0001). Adverse events were similar between groups. Conclusion: Omalizumab significantly improved endoscopic, clinical, and patient-reported outcomes in severe CRSwNP with inadequate response to intranasal corticosteroids, and it was well tolerated
Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC
The uncertainty on the calorimeter energy response to jets of particles is
derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is measured and
compared to the Monte Carlo simulation using proton-proton collisions at
centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009
and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter
response to specific types of particles (positively and negatively charged
pions, protons, and anti-protons) is measured and compared to the Monte Carlo
predictions. Finally, the jet energy scale uncertainty is determined by
propagating the response uncertainty for single charged and neutral particles
to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3%
for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table,
submitted to European Physical Journal
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