9,674 research outputs found

    Keck/MOSFIRE Spectroscopy of z=7-8 Galaxies: Lyα\alpha Emission from a Galaxy at z=7.66

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    We report the results from some of the deepest Keck/Multi-Object Spectrometer For Infra-Red Exploration data yet obtained for candidate z7z \gtrsim 7 galaxies. Our data show one significant line detection with 6.5σ\sigma significance in our combined 10 hr of integration which is independently detected on more than one night, thus ruling out the possibility that the detection is spurious. The asymmetric line profile and non-detection in the optical bands strongly imply that the detected line is Lyα\alpha emission from a galaxy at zz(Lyα)=7.6637±0.0011\alpha)=7.6637 \pm 0.0011, making it the fourth spectroscopically confirmed galaxy via Lyα\alpha at z>7.5z>7.5. This galaxy is bright in the rest-frame ultraviolet (UV; MUV21.2M_{\rm UV} \sim -21.2) with a moderately blue UV slope (β=2.20.2+0.3\beta=-2.2^{+0.3}_{-0.2}), and exhibits a rest-frame Lyα\alpha equivalent width of EW(Lyα\alpha) 15.63.6+5.9\sim 15.6^{+5.9}_{-3.6} \AA. The non-detection of the 11 other zz \sim 7-8 galaxies in our long 10 hr integration, reaching a median 5σ\sigma sensitivity of 28 \AA\ in the rest-frame EW(Lyα\alpha), implies a 1.3σ\sigma deviation from the null hypothesis of a non-evolving distribution in the rest-frame EW(Lyα\alpha) between 3<z<63<z<6 and z=z= 7-8. Our results are consistent with previous studies finding a decline in Lyα\alpha emission at z>6.5z>6.5, which may signal the evolving neutral fraction in the intergalactic medium at the end of the reionization epoch, although our weak evidence suggests the need for a larger statistical sample to allow for a more robust conclusion.Comment: 10 pages, 4 figures, ApJ, in pres

    Ergodicity breaking in strong and network-forming glassy system

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    The temperature dependence of the non-ergodicity factor of vitreous GeO2_2, fq(T)f_{q}(T), as deduced from elastic and quasi-elastic neutron scattering experiments, is analyzed. The data are collected in a wide range of temperatures from the glassy phase, up to the glass transition temperature, and well above into the undercooled liquid state. Notwithstanding the investigated system is classified as prototype of strong glass, it is found that the temperature- and the qq-behavior of fq(T)f_{q}(T) follow some of the predictions of Mode Coupling Theory. The experimental data support the hypothesis of the existence of an ergodic to non-ergodic transition occurring also in network forming glassy systems

    Long-term placement of continuous popliteal nerve block catheter for management of a wounded patient in a combat field environment: A case report

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    Continuous peripheral nerve block is a relevant part of multimodal treatment of postoperative pain. In this context the continuous popliteal nerve block is described as an option for postoperative pain management for surgical procedures on the leg, and particularly on the ankle and foot. We applied continuous popliteal nerve block for different types of anesthesia and postoperative pain management via the same catheter. No clear evidence of this specific use has been described in the literature. A 38 year-old patient wounded in combat with a displaced fracture of left tibia and extensive loss of substance needed orthopedic surgeries as well as several reconstructive procedures. A continuous popliteal nerve block was applied via ultrasound-guided catheter for anesthesia at different times, and postoperative pain control for all surgical procedures. The continuous popliteal nerve block and its long-term positioning, of non-common evidence in literature, was utilized to treat a poly-traumatized patient, thereby avoiding repeated general anesthesia and opioid use and their adverse effects. This technique, within a complicated combat field environment, was demonstrated to be clinically effective with high patient satisfaction

    Association between Resistin Levels and All-Cause and Cardiovascular Mortality: A New Study and a Systematic Review and Meta-Analysis.

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    CONTEXT: Studies concerning the association between circulating resistin and mortality risk have reported, so far, conflicting results. OBJECTIVE: To investigate the association between resistin and both all-cause and cardiovascular (CV) mortality risk by 1) analyzing data from the Gargano Heart Study (GHS) prospective design (n=359 patients; 81 and 58 all-cause and CV deaths, respectively); 2) performing meta-analyses of all published studies addressing the above mentioned associations. DATA SOURCE AND STUDY SELECTION: MEDLINE and Web of Science search of studies reporting hazard ratios (HR) of circulating resistin for all-cause or CV mortality. DATA EXTRACTION: Performed independently by two investigators, using a standardized data extraction sheet. DATA SYNTHESIS: In GHS, adjusted HRs per one standard deviation (SD) increment in resistin concentration were 1.28 (95% CI: 1.07-1.54) and 1.32 (95% CI: 1.06-1.64) for all-cause and CV mortality, respectively. The meta-analyses included 7 studies (n=4016; 961 events) for all-cause mortality and 6 studies (n=4,187: 412 events) for CV mortality. Pooled HRs per one SD increment in resistin levels were 1.21 (95% CI: 1.03-1.42, Q-test p for heterogeneity<0.001) and 1.05 (95% CI: 1.01-1.10, Q-test p for heterogeneity=0.199) for all-cause and CV mortality, respectively. At meta-regression analyses, study mean age explained 9.9% of all-cause mortality studies heterogeneity. After adjusting for age, HR for all-cause mortality was 1.24 (95% CI: 1.06-1.45). CONCLUSIONS: Our results provide evidence for an association between circulating resistin and mortality risk among high-risk patients as are those with diabetes and coronary artery disease

    Physical properties of z~4 LBGs: differences between galaxies with and without Ly-alpha emission

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    We have analysed the physical properties of z~4 Lyman Break Galaxies observed in the GOODS-S survey, in order to investigate the possible differences between galaxies where the Ly-alpha is present in emission, and those where the line is absent or in absorption. The objects have been selected from their optical color and then spectroscopically confirmed by Vanzella et al. (2005). From the public spectra we assessed the nature of the Ly-alpha emission and divided the sample into galaxies with Ly-alpha in emission and objects without Ly-alpha line (i.e. either absent or in absorption). We have then used the complete photometry, from U band to mid infrared from the GOODS-MUSIC database, to study the observational properties of the galaxies, such as UV spectral slopes and optical to mid-infrared colors, and the possible differences between the two samples. Finally through standard spectral fitting tecniques we have determined the physical properties of the galaxies, such as total stellar mass, stellar ages and so on, and again we have studied the possible differences between the two samples. Our results indicate that LBG with Ly-alpha in emission are on average a much younger and less massive population than the LBGs without Ly-alpha emission. Both populations are forming stars very actively and are relatively dust free, although those with line emission seem to be even less dusty on average. We briefly discuss these results in the context of recent models for the evolution of Lyman break galaxies and Ly-alpha emitters.Comment: Accepted for publication in A&A. Uses aa.cls, 6 pages, 3 figure

    Comparison of the Diagnostic Accuracy of Brain Natriuretic Peptide (BNP) and the N-Terminal Part of the Propeptide of BNP Immunoassays in Chronic and Acute Heart Failure: A Systematic Review

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    Abstract Study aim The current study compares the diagnostic accuracy of BNP and NT-proBNP assays for the diagnosis of heart failure, according to evidence based laboratory medicine (EBLM) principles. Methods In May 2006, studies specifically designed to compare the diagnostic accuracy of BNP and NT-proBNP assays were selected by means of a computerized literature search performed on National Library of Medicine. The comparison took into account the area under the curve (AUC) and diagnostic odds ratio (DOR) derived from ROC analysis of original studies. Results Both BNP and NT-proBNP assays were found to be clinically useful for the diagnosis of heart failure. A meta-analysis of these data was made difficult by the heterogeneity of data, regarding patient population, diagnostic criteria, end-points and immunoassay methods for both BNP and NT-proBNP. Separate meta-analyses were performed for acute and chronic heart failure. In chronic heart failure, the diagnostic odds ratio (DOR) for BNP assay (DOR 8.44, 95% CI 4.66 – 15.30) was not significantly different from NT-proBNP one (23.36, 95% CI 9.38 – 58.19). In patients with acute heart failure, the mean DOR for BNP assay was 16.46 (95% CI 10.65 – 25.43) and for NT-proBNP assay 18.61 (95% CI 12.99 – 26.65), without a significant difference. Conclusion Our results indicate that both BNP and NT-proBNP assays have a high degree of diagnostic accuracy and clinical relevance in both acute and chronic heart failure
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