308 research outputs found

    Confirmation Via the Continuum-Fitting Method that the Spin of the Black Hole in Cygnus X-1 is Extreme

    Full text link
    In Gou et al. (2011), we reported that the black hole primary in the X-ray binary Cygnus X-1 is a near-extreme Kerr black hole with a spin parameter a*>0.95(3{\sigma}). We confirm this result while setting a new and more stringent limit: a*>0.983 at the 3{\sigma}(99.7%) level of confidence. The earlier work, which was based on an analysis of all three useful spectra that were then available, was possibly biased by the presence in these spectra of a relatively strong Compton power-law component: The fraction of the thermal seed photons scattered into the power law was f_s=23-31%, while the upper limit for reliable application of the continuum-fitting method is f_s<25%. We have subsequently obtained six additional spectra of Cygnus X-1 suitable for the measurement of spin. Five of these spectra are of high quality with f_s in the range 10% to 19%, a regime where the continuum-fitting method has been shown to deliver reliable results. Individually, the six spectra give lower limits on the spin parameter that range from a*>0.95 to a*>0.98, allowing us to conservatively conclude that the spin of the black hole is a*>0.983 (3{\sigma}).Comment: 14 pages in emulated ApJ format, including 6 figures and 4 tables, ApJ in press. Discussion on the pileup effect to our spin measurement is added, including a subsection and a new figure, to reflect the referee's comments; the conclusions are unchange

    One century of hydrological monitoring in two small catchments with different forest coverage

    Get PDF
    Long-term data on precipitation and runoff are essential to draw firm conclusions about the behavior and trends of hydrological catchments that may be influenced by land use and climate change. Here the longest continuous runoff records from small catchments (<1km2) in Switzerland (and possibly worldwide) are reported. The history of the hydrological monitoring in the Sperbel- and Rappengraben (Emmental) is summarized, and inherent uncertainties in the data arising from the operation of the gauges are described. The runoff stations operated safely for more than 90% of the summer months when most of the major flood events occurred. Nevertheless, the absolute values of peak runoff during the largest flood events are subject to considerable uncertainty. The observed differences in average, base, and peak runoff can only partly be attributed to the substantial differences in forest coverage. This treasure trove of data can be used in various ways, exemplified here with an analysis of the generalized extreme value distributions of the two catchments. These distributions, and hence flood return periods, have varied greatly in the course of one century, influenced by the occurrence of single extreme events. The data will be made publicly available for the further analysis of the mechanisms governing the runoff behavior of small catchments, as well as for testing stochastic and deterministic model

    Accelerated angiogenesis by continuous medium flow with vascular endothelial growth factor inside tissue-engineered trachea

    Get PDF
    Objective: To test the effects of a continuous medium flow inside DegraPol® scaffolds on the reepithelialization and revascularization processes of a tissue-engineered trachea prosthesis. Methods: In this proof-of-principle study a continuous medium flow was maintained within a tubular DegraPol® scaffold by an inserted porous catheter connected to a pump system. The impact of the intra-scaffold medium flow on the survival of a tracheal epithelial sheet wrapped around and on chondrocyte delivery to the DegraPol® scaffold was studied. In the chick embryo, chorioallantoic membrane (CAM) model angiogenesis within the biomaterial was investigated. Results: Scanning electronic microscopy (SEM) images showed an intact epithelial layer after a 2-week support by continuous medium flow underneath. On histology, three-dimensional cell growth was detected in the continuous delivery group. The CAM assay showed that angiogenesis was enhanced within the DegraPol® scaffolds when vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) was added to the perfusate. Conclusions: Taken together, these results demonstrated that the built-in perfusion system within DegraPol® scaffolds was able to maintain an intact tracheal epithelial layer, allowed a continuous delivery of cells, and kept an efficient VEGF/VPF expression level which accelerated angiogenic response in the CAM assay. This design combines the in vitro and in vivo parts of tissue engineering and offers the possibility to be used as an in vivo bioreactor implanted for the tissue-engineered reconstruction of trachea and of other organ

    Independent External Validation of a Preoperative Prediction Model for Delirium After Cardiac Surgery: A Prospective Observational Cohort Study

    Full text link
    Objective: This investigation provided independent external validation of an existing preoperative risk prediction model. Design: A prospective observational cohort study of patients undergoing cardiac surgery covering the period between April 16, 2018 and January 18, 2022. Setting: Two academic hospitals in Switzerland. Participants: Adult patients (≥60 years of age) who underwent elective cardiac surgery, including coronary artery bypass graft, mitral or aortic valve replacement or repair, and combined procedures. Interventions: None. Measurements and main results: The primary outcome measure was the incidence of postoperative delirium (POD) in the intensive or intermediate care unit, diagnosed using the Intensive Care Delirium Screening Checklist. The prediction model contained 4 preoperative risk factors to which the following points were assigned: Mini-Mental State Examination (MMSE) score ≤23 received 2 points; MMSE 24-27, Geriatric Depression Scale (GDS) >4, prior stroke and/or transient ischemic attack (TIA), and abnormal serum albumin (≤3.5 or ≥4.5 g/dL) received 1 point each. The missing data were handled using multiple imputation. In total, 348 patients were included in the study. Sixty patients (17.4%) developed POD. For point levels in the prediction model of 0, 1, 2, and ≥3, the cumulative incidence of POD was 12.6%, 22.8%, 25.8%, and 35%, respectively. The validation resulted in a pooled area under the receiver operating characteristics curve of 0.60 (median CI, 0.525-0.679). Conclusions: The evaluated predictive model for delirium after cardiac surgery in this patient cohort showed only poor discriminative capacity but fair calibration. Keywords: External validation; cardiac surgery; delirium; predictio

    Soziale Milieus und Weiterbildung: Beiträge zur Fachtagung "Zur Relativitätstheorie des Bildungsverhaltens - Soziale Milieus, Bedürfnisse und Weiterbildungsmotivation" vom 5. Juni 2013 in Wien

    Full text link
    Die Tagung "Zur Relativitätstheorie des Bildungsverhaltens - Soziale Milieus, Bedürfnisse und Weiterbildungsmotivation", die am 5. Juni 2013 im Kardinal König Haus in Wien stattfand, hatte zum Ziel, die Abhängigkeit von Weiterbildungsmotivation und Weiterbildungsverhalten von der Lebenswelt der Menschen her zu verdeutlichen und zu diskutieren. Gleichzeitig wurde der Fokus auf benachteiligte Zielgruppen gelegt, und ebenso wurden Möglichkeiten aufgezeigt, wie Weiterbildungsangebote entwickelt werden können, um den Bedürfnissen der jeweiligen Zielgruppe gerecht zu werden Der vorliegende AMS report enthält die erweiterten Versionen ausgewählter Vorträge, die anlässlich dieser Tagung gehalten wurden. Die Veranstalter der Tagung, die Caritas Österreich, die Abt. Arbeitsmarktforschung und Berufsinformation des AMS Österreich sowie das sozialwissenschaftliche Forschungsinstitut abif - Analyse, Beratung und interdisziplinäre Forschung, hoffen, Ihnen mit diesem AMS report eine interessante und anregende Lektüre vorlegen zu können

    Unraveling site fidelity and residency patterns of sperm whales in the insular oceanic waters of Macaronesia

    Get PDF
    Knowledge of the distribution and residency of pelagic marine megafauna, particularly deep-diving species, is scarce due to their high mobility over difficult-to-access oceanic areas and long periods underwater. However, the threatened status of many of these species, such as the sperm whale Physeter macrocephalus, increases the need to obtain quantitative data to support conservation measures. In the warm temperate waters of Macaronesia (Eastern North Atlantic), sperm whales occur year-round in a set of island systems (the Azores, Madeira, and the Canaries), mainly in social groups of females and juveniles with the occasional visits of mature males. Although it is known that they perform inter-archipelago movements, information on site fidelity and residency times is still scarce. Here, based on photographic-identification data, site fidelity and residency times of sperm whales were estimated for subareas of the Azores and the Madeira archipelagos, with a preliminary assessment for a subarea of the Canaries. The Azores and Madeira subareas presented similar proportions of individuals with recaptures (~25%), mainly inter-annual, while in the subarea of the Canaries, only <10% of the individuals were recaptured. Standardized Site Fidelity Indexes showed very low values (<0.01) for both the Azores and Madeira subareas. Lagged identification rates based on models including emigration and reimmigration estimated that an average of 44.8 individuals (SE=4.9) spent 12.9 days (SE=1.5) in the Azores before leaving for 99.1 days (SE=12.5), while 8.4 individuals (SE=16.1) spent 0.8 day (SE=6.6) in Madeira before leaving for 8.6 days (SE=6.9), with a very low mortality rate. This study i) indicates a degree of residency of about ¼ of the identified individuals for the Azores and Madeira subareas and ii) supports that these oceanic archipelagos constitute an important habitat for a Vulnerable species in the Atlantic. Moreover, it also highlights the importance of combining data from opportunistic and dedicated surveys and joint national and international efforts toward the conservation of marine megafauna.This study had the support of FCT through the strategic project UIDB/04292/2020 awarded to MARE and through the project LA/P/0069/2020 granted to the Associate Laboratory ARNET. It was also supported through the strategic project M1420-01-0142-FEDER-000001 for the Oceanic Observatory of Madeira and from Oceanário de Lisboa and Oceano Azul Foundation through Whale Tales Project (ODL/2019/003). RF was supported by the FCT grant SFRH/BD/147225/2019, MF by the MAC2/1.1a/385 in the framework of INTERTAGUA (MAC INTERREG 2014-2020), AD by ARDITI throughout the project M1420-09-5369-FSE-000002 and FA by the FCT project UIDP/04292/2020 granted to MARE.info:eu-repo/semantics/publishedVersio

    RelA regulates CXCL1/CXCR2-dependent oncogene-induced senescence in murine Kras-driven pancreatic carcinogenesis

    Get PDF
    Tumor suppression that is mediated by oncogene-induced senescence (OIS) is considered to function as a safeguard during development of pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms that regulate OIS in PDAC are poorly understood. Here, we have determined that nuclear RelA reinforces OIS to inhibit carcinogenesis in the Kras mouse model of PDAC. Inactivation of RelA accelerated pancreatic lesion formation in Kras mice by abrogating the senescence-associated secretory phenotype (SASP) gene transcription signature. Using genetic and pharmacological tools, we determined that RelA activation promotes OIS via elevation of the SASP factor CXCL1 (also known as KC), which activates CXCR2, during pancreatic carcinogenesis. In Kras mice, pancreas-specific inactivation of CXCR2 prevented OIS and was correlated with increased tumor proliferation and decreased survival. Moreover, reductions in CXCR2 levels were associated with advanced neoplastic lesions in tissue from human pancreatic specimens. Genetically disabling OIS in Kras mice caused RelA to promote tumor proliferation, suggesting a dual role for RelA signaling in pancreatic carcinogenesis. Taken together, our data suggest a pivotal role for RelA in regulating OIS in preneoplastic lesions and implicate the RelA/CXCL1/CXCR2 axis as an essential mechanism of tumor surveillance in PDAC

    Cooperation of N- and C-terminal substrate transmembrane domain segments in intramembrane proteolysis by Îł-secretase

    Get PDF
    Intramembrane proteases play a pivotal role in biology and medicine, but how these proteases decode cleavability of a substrate transmembrane (TM) domain remains unclear. Here, we study the role of conformational flexibility of a TM domain, as determined by deuterium/hydrogen exchange, on substrate cleavability by gamma-secretase in vitro and in cellulo. By comparing hybrid TMDs based on the natural amyloid precursor protein TM domain and an artificial poly-Leu non-substrate, we find that substrate cleavage requires conformational flexibility within the N-terminal half of the TMD helix (TM-N). Robust cleavability also requires the C-terminal TM sequence (TM-C) containing substrate cleavage sites. Since flexibility of TM-C does not correlate with cleavage efficiency, the role of the TM-C may be defined mainly by its ability to form a cleavage-competent state near the active site, together with parts of presenilin, the enzymatic component of gamma-secretase. In sum, cleavability of a gamma-secretase substrate appears to depend on cooperating TM domain segments, which deepens our mechanistic understanding of intramembrane proteolysis. Deuterium/hydrogen exchange shows that conformational flexibility of the hybrid transmembrane domains (TMD) of amyloid precursor proteins plays a role in TMD cleavability by gamma-secretase in vitro and in cellulo
    • …
    corecore