744 research outputs found
Revisiting light neutralino scenarios in the MSSM
We revisit the case of a light neutralino LSP in the framework of the MSSM.
We consider a model with eleven free parameters. We show that all scenarios
where the annihilation of light neutralinos rely mainly on the exchange of a
light pseudoscalar are excluded by direct detection searches and by Fermi
measurements of the gamma-flux from dwarf spheroidal galaxies. On the other
hand, we find scenarios with light sleptons that satisfy all collider and
astroparticle physics constraints. In this case, the lower limit on the LSP
mass is 12.6 GeV. We discuss how the parameter space of the model will be
further probed by new physics searches at the LHC.Comment: 7 pages, 8 figure
The Use of Quality Cost Measurement Systems for Improving Profitability
The focus of this study was to determine if t he use of a quality cost measurement system will allow companies to track and analyze costs and provide a means of improving profitability. Focusing on the philosophies and theories developed by W. Edwards Deming, J .M. Juran, and Philip Crosby, three of the leading authorities in the quality control field, a quality control system can be designed to track and analyze quality costs. Quality costs have been grouped into three categories : Prevention costs, Appraisal costs, and Failure costs. Prevention costs are those associated with preventing poor quality such as, new machinery, inspections, and training. Appraisal costs are associated with analysis of finished products and other such functions. Failure costs are divided into two further categories: Internal failure and external failure. Internal failures occur as a result of problems within the company. External failures are caused by problems with raw materials from suppliers or problems with consumers. Failure costs include such items as scrap, rework of product, and placating irate customers. The purpose of this study was to determine if a correlation exists between quality cost measurement and profitability. Information was gathered through secondary data collection, Magazine articles and published studies were the primary source of secondary data. Hypothetical case scenarios were also utilized.
The following hypothesis was tested: If quality costs are tracked and analyzed, they can be controlled in order to increase profitability.
Results of the analysis failed to supply sufficient information to support t he hypothesis completely , but a positive correlation between quality cost measurement and profitability was revealed. Because of insufficient data, it was concluded that the study needed to be revised by changing the sampling frame and determining more useful analysis calculations
Impact of the indexed effective orifice area on mid-term cardiac-related mortality after aortic valve replacement
Background There has been ongoing controversy as to whether prosthesis-patient mismatch (PPM, defined as indexed effective orifice area (EOAI) <0.85 m(2)/cm(2)) influences mortality after aortic valve replacement (AVR). In most studies, PPM is anticipated by reference tables based on mean EOAs as opposed to individual assessment. These reference values may not reflect the actual in vivo EOAI and hence, the presence or absence of PPM may be based on false assumptions. Objective To assess the impact of small prosthesis EOA on survival after aortic valve replacement AVR. Methods 645 patients had undergone an AVR between 2000 and 2007 entered the study. All patients underwent transthoracic echocardiography for determination of the actual EOAI within 6 months postoperatively. In order to predict time from surgery to death a proportional hazards model for competing risks (cardiac death vs death from other causes) was used. EOAI was entered as a continuous variable. Results PPM occurred in 40% of the patients. After a median follow-up of 2.35 years, 92.1% of the patients were alive. The final Cox regression model showed a significantly increased risk for cardiac death among patients with a smaller EOAI (HR=0.32, p=0.022). The effect of EOAI on the 2-5 year mortality risk was demonstrated by risk plots. Conclusions In contrast to previous studies these EOAI values were obtained through postoperative echocardiography, substantially improving the accuracy of measurement, and the EOAI was modelled as a continuous variable. There was a significantly improved survival for larger EOAIs following AVR. Strategies to avoid PPM should become paramount during AVR
Orally Active MMP-1 Sparing α-tetrahydropyranyl and α-piperidinyl Sulfone Matrix Metalloproteinase (MMP) Inhibitors with Efficacy in Cancer, Arthritis, and Cardiovascular Disease
α-Sulfone-α-piperidine and α-tetrahydropyranyl hydroxamates were explored that are potent inhibitors of MMP’s-2, -9, and -13 that spare MMP-1, with oral efficacy in inhibiting tumor growth in mice and left-ventricular hypertrophy in rats and in the bovine cartilage degradation ex vivo explant system. α-Piperidine 19v (SC-78080/SD-2590) was selected for development toward the initial indication of cancer, while α-piperidine and α-tetrahydropyranyl hydroxamates 19w (SC-77964) and 9i (SC-77774), respectively, were identified as backup compounds
The Influence of Social Isolation and Medical Comorbidities on Geriatric Congestive Heart Failure Hospital Readmissions
CONTEXT Social isolation and comorbidities are likely to have a significant level of influence on the healthcare use patterns of geriatric patients with ongoing congestive heart failure (CHF)-related needs. METHODS A retrospective study was conducted in a specialized emergency department (ED) with a sample of 286 geriatric CHF patients who initially received CHF-related care over a six-month period. Social isolation levels were assessed using a pre-existing four-point screening tool used in the study setting and composite comorbidity was gauged using the Charlson Comorbidity Index method. Subjects were categorized into either “less than 30-day readmission” or “greater than 30-day readmission/non-readmitted” sample subgroups. The setting was a single 304-bed community hospital with approximately 45,000 annual ED visits. The analytic sample was comprised of geriatric patients 65+ years of age with an ICD-9 code corresponding to CHF. RESULTS There were no statistically significant differences between earlier hospital readmission versus later/non-readmitted sample patients when grouped by age, race, gender or level of measured social isolation. However, composite comorbidity scores were significantly lower for patients in the \u3e30-day/non-readmitted subgroup compared to earlier readmission patients. CONCLUSIONS These initial study results suggest that a larger proportion of CHF hospital readmissions may be more heavily influenced by clinical factors than social living arrangements. Future studies with larger samples and validated measures of social isolation are needed to inform the development and testing of programs for geriatric CHF patients striving to avoid unnecessary hospital readmissions and adverse health outcomes
The environmental dependence of the stellar mass-size relation in STAGES galaxies
We present the stellar mass-size relations for elliptical, lenticular, and
spiral galaxies in the field and cluster environments using HST/ACS imaging and
data from the Space Telescope A901/2 Galaxy Evolution Survey (STAGES). We use a
large sample of ~1200 field and cluster galaxies, and a sub-sample of cluster
core galaxies, and quantify the significance of any putative environmental
dependence on the stellar mass-size relation. For elliptical, lenticular, and
high-mass (log M*/M_sun > 10) spiral galaxies we find no evidence to suggest
any such environmental dependence, implying that internal drivers are governing
their size evolution. For intermediate/low-mass spirals (log M*/M_sun < 10) we
find evidence, significant at the 2-sigma level, for a possible environmental
dependence on galaxy sizes: the mean effective radius a_e for lower-mass
spirals is ~15-20 per cent larger in the field than in the cluster. This is due
to a population of low-mass large-a_e field spirals that are largely absent
from the cluster environments. These large-a_e field spirals contain extended
stellar discs not present in their cluster counterparts. This suggests the
fragile extended stellar discs of these spiral galaxies may not survive the
environmental conditions in the cluster. Our results suggest that internal
physical processes are the main drivers governing the size evolution of
galaxies, with the environment possibly playing a role affecting only the discs
of intermediate/low-mass spirals.Comment: 16 pages, 10 figures, accepted to MNRA
Orally Bioavailable Dual MMP-1/MMP-14 Sparing, MMP-13 Selective Alpha-sulfone Hydroxamates
A series of phenyl piperidine α-sulfone hydroxamate derivatives has been prepared utilizing a combination of solution-phase and resin-bound library technologies to afford compounds that are potent and highly selective for MMP-13, are dual-sparing of MMP-1 and MMP-14 (MT1-MMP) and exhibit oral bioavailability in rats
Effort estimation of FLOSS projects: A study of the Linux kernel
This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 SpringerEmpirical research on Free/Libre/Open Source Software (FLOSS) has shown that developers tend to cluster around two main roles: “core” contributors differ from “peripheral” developers in terms of a larger number of responsibilities and a higher productivity pattern. A further, cross-cutting characterization of developers could be achieved by associating developers with “time slots”, and different patterns of activity and effort could be associated to such slots. Such analysis, if replicated, could be used not only to compare different FLOSS communities, and to evaluate their stability and maturity, but also to determine within projects, how the effort is distributed in a given period, and to estimate future needs with respect to key points in the software life-cycle (e.g., major releases). This study analyses the activity patterns within the Linux kernel project, at first focusing on the overall distribution of effort and activity within weeks and days; then, dividing each day into three 8-hour time slots, and focusing on effort and activity around major releases. Such analyses have the objective of evaluating effort, productivity and types of activity globally and around major releases. They enable a comparison of these releases and patterns of effort and activities with traditional software products and processes, and in turn, the identification of company-driven projects (i.e., working mainly during office hours) among FLOSS endeavors. The results of this research show that, overall, the effort within the Linux kernel community is constant (albeit at different levels) throughout the week, signalling the need of updated estimation models, different from those used in traditional 9am–5pm, Monday to Friday commercial companies. It also becomes evident that the activity before a release is vastly different from after a release, and that the changes show an increase in code complexity in specific time slots (notably in the late night hours), which will later require additional maintenance efforts
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