1,355 research outputs found

    The Neutral ISM in Nearby Luminous Compact Blue Galaxies

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    We observed 20 nearby Luminous Compact Blue Galaxies (LCBGs) in HI and CO(J=2-1) with the GBT and JCMT. These ~L^star galaxies are blue, high surface brightness, starbursting, high metallicity galaxies with an underlying older stellar population. They are common at z~1, but rare in the local Universe. It has been proposed that intermediate redshift LCBGs may be the progenitors of local dwarf ellipticals or low luminosity spirals, or that they may be more massive disks forming from the center outward to become L^star galaxies. To discriminate among various possible evolutionary scenarios, we have measured the dynamical masses and gas depletion time scales of this sample of nearby LCBGs. We find that local LCBGs span a wide range of dynamical masses, from 4 x 10^9 to 1 x 10^11 M_solar (measured within R_25). Molecular gas in local LCBGs is depleted quite quickly, in 30 to 200 million years. The molecular plus atomic gas is depleted in 30 million to 10 billion years; however, ~80% of the local LCBGs deplete their gas in less than 5 billion years. As LCBGs are heterogeneous in both dynamical mass and gas depletion time scales, they are not likely to evolve into one homogeneous galaxy class.Comment: 4 pages, 2 figures, to be published in 4th Cologne-Bonn-Zermatt-Symposium, Eds. S. Pfalzner, C. Kramer, C. Straubmeier, and A. Heithause

    A Comparison of Initial Antiretroviral Therapy in the Swiss HIV Cohort Study and the Recommendations of the International AIDS Society-USA

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    BACKGROUND: In order to facilitate and improve the use of antiretroviral therapy (ART), international recommendations are released and updated regularly. We aimed to study if adherence to the recommendations is associated with better treatment outcomes in the Swiss HIV Cohort Study (SHCS). METHODS: Initial ART regimens prescribed to participants between 1998 and 2007 were classified according to IAS-USA recommendations. Baseline characteristics of patients who received regimens in violation with these recommendations (violation ART) were compared to other patients. Multivariable logistic and linear regression analyses were performed to identify associations between violation ART and (i) virological suppression and (ii) CD4 cell count increase, after one year. RESULTS: Between 1998 and 2007, 4189 SHCS participants started 241 different ART regimens. A violation ART was started in 5% of patients. Female patients (adjusted odds ratio aOR 1.83, 95%CI 1.28-2.62), those with a high education level (aOR 1.49, 95%CI 1.07-2.06) or a high CD4 count (aOR 1.53, 95%CI 1.02-2.30) were more likely to receive violation ART. The proportion of patients with an undetectable viral load (<400 copies/mL) after one year was significantly lower with violation ART than with recommended regimens (aOR 0.54, 95% CI 0.37-0.80) whereas CD4 count increase after one year of treatment was similar in both groups. CONCLUSIONS: Although more than 240 different initial regimens were prescribed, violations of the IAS-USA recommendations were uncommon. Patients receiving these regimens were less likely to have an undetectable viral load after one year, which strengthens the validity of these recommendations

    Logical Analysis of Data (LAD) model for the early diagnosis of acute ischemic stroke

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    <p>Abstract</p> <p>Background</p> <p>Strokes are a leading cause of morbidity and the first cause of adult disability in the United States. Currently, no biomarkers are being used clinically to diagnose acute ischemic stroke. A diagnostic test using a blood sample from a patient would potentially be beneficial in treating the disease.</p> <p>Results</p> <p>A classification approach is described for differentiating between proteomic samples of stroke patients and controls, and a second novel predictive model is developed for predicting the severity of stroke as measured by the National Institutes of Health Stroke Scale (NIHSS). The models were constructed by applying the Logical Analysis of Data (LAD) methodology to the mass peak profiles of 48 stroke patients and 32 controls. The classification model was shown to have an accuracy of 75% when tested on an independent validation set of 35 stroke patients and 25 controls, while the predictive model exhibited superior performance when compared to alternative algorithms. In spite of their high accuracy, both models are extremely simple and were developed using a common set consisting of only 3 peaks.</p> <p>Conclusion</p> <p>We have successfully identified 3 biomarkers that can detect ischemic stroke with an accuracy of 75%. The performance of the classification model on the validation set and on cross-validation does not deteriorate significantly when compared to that on the training set, indicating the robustness of the model. As in the case of the LAD classification model, the results of the predictive model validate the function constructed on our support-set for approximating the severity scores of stroke patients. The correlation and root mean absolute error of the LAD predictive model are consistently superior to those of the other algorithms used (Support vector machines, C4.5 decision trees, Logistic regression and Multilayer perceptron).</p

    How does a cadaver model work for testing ultrasound diagnostic capability for rheumatic-like tendon damage?

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    To establish whether a cadaver model can serve as an effective surrogate for the detection of tendon damage characteristic of rheumatoid arthritis (RA). In addition, we evaluated intraobserver and interobserver agreement in the grading of RA-like tendon tears shown by US, as well as the concordance between the US findings and the surgically induced lesions in the cadaver model. RA-like tendon damage was surgically induced in the tibialis anterior tendon (TAT) and tibialis posterior tendon (TPT) of ten ankle/foot fresh-frozen cadaveric specimens. Of the 20 tendons examined, six were randomly assigned a surgically induced partial tear; six a complete tear; and eight left undamaged. Three rheumatologists, experts in musculoskeletal US, assessed from 1 to 5 the quality of US imaging of the cadaveric models on a Likert scale. Tendons were then categorized as having either no damage, (0); partial tear, (1); or complete tear (2). All 20 tendons were blindly and independently evaluated twice, over two rounds, by each of the three observers. Overall, technical performance was satisfactory for all items in the two rounds (all values over 2.9 in a Likert scale 1-5). Intraobserver and interobserver agreement for US grading of tendon damage was good (mean κ values 0.62 and 0.71, respectively), with greater reliability found in the TAT than the TPT. Concordance between US findings and experimental tendon lesions was acceptable (70-100 %), again greater for the TAT than for the TPT. A cadaver model with surgically created tendon damage can be useful in evaluating US metric properties of RA tendon lesions

    Development and Validation of a Composite Programmatic Assessment Tool for HIV Therapy

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    Background We developed and validated a new and simple metric, the Programmatic Compliance Score (PCS), based on the IAS-USA antiretroviral therapy management guidelines for HIV-infected adults, as a predictor of all-cause mortality, at a program-wide level. We hypothesized that non-compliance would be associated with the highest probability of mortality. Methods and Findings 3543 antiretroviral-naive HIV-infected patients aged ≥19 years who initiated antiretroviral therapy between January 1, 2000 and August 31, 2009 in British Columbia (BC), Canada, were followed until August 31, 2010. The PCS is composed by six non-performance indicators based on the IAS-USA guidelines: (1) having &lt;3 CD4 count tests in the first year after starting antiretroviral therapy; (2) having &lt;3 plasma viral load tests in the first year after starting antiretroviral therapy; (3) not having drug resistance testing done prior to starting antiretroviral therapy; (4) starting on a non-recommended antiretroviral therapy regimen; (5) starting therapy with CD4 &lt;200 cells/mm3; and (6) not achieving viral suppression within 6 months since antiretroviral therapy initiation. The sum of these six indicators was used to develop the PCS score - higher score indicates poorer performance. The main outcome was all-cause mortality. Each PCS component was independently associated with mortality. In the mortality analysis, the odds ratio (OR) for PCS ≥4 versus 0 was 22.37 (95% CI 10.46–47.84). Conclusions PCS was strongly associated with all-cause mortality. These results lend independent validation to the IAS-USA treatment guidelines for HIV-infected adults. Further efforts are warranted to enhance the PCS as a means to further improve clinical outcomes. These should be specifically evaluated and targeted at healthcare providers and patients

    Rapid ascent of rhyolitic magma at Chaitén volcano, Chile

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    International audienceAlthough rhyolite magma has fuelled some of the Earth's largest explosive volcanic eruptions, our understanding of these events is incomplete due to the previous lack of direct observation of these eruptions. On 1 May 2008, Chaitén volcano in Chile erupted rhyolite magma unexpectedly and explosively. Here, petrological and experimental data are presented that indicate that the hydrous rhyolite magma at Chaitén ascended very rapidly from storage depth to near-surface, with velocities of the order of one metre per second
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