3,589 research outputs found

    Effects of Hikers and Boats on Tule Elk Behavior in a National Park Wilderness Area

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    Human disturbance of wildlife may cause disruption of normal feeding, resting, reproduction, or care for juveniles. Such disturbance may be particularly undesirable in federally managed wilderness areas designed to minimize human influences on natural resources. We recorded tule elk (Cervus elephus nannodes) responses (standing, walking away, running) to off-trail hikers, off-shore boats, and other natural and anthropogenic factors in Point Reyes National Seashore in northern California during 2002 to 2008. Most disturbance behaviors were related to other elk exhibiting rutting behaviors, but off-trail hikers still explained a 100% increase and off-shore boats a 15% increase in baseline disturbance behaviors by elk. However, off-trail hikers and boats did not cause elk to enter or leave the study area during the sample periods. Elk were more prone to human disturbance when herd sizes wereand, to a lesser extent, offshore boats appear to disturb natural tule elk behavior, but the physiological or population-level effects of this disturbance are unknown. Our quantitative results may help park managers minimize or mitigate human–elk interactions in wilderness areas

    A two-way photonic interface for linking Sr+ transition at 422 nm to the telecommunications C-band

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    We report a single-stage bi-directional interface capable of linking Sr+ trapped ion qubits in a long-distance quantum network. Our interface converts photons between the Sr+ emission wavelength at 422 nm and the telecoms C-band to enable low-loss transmission over optical fiber. We have achieved both up- and down-conversion at the single photon level with efficiencies of 9.4% and 1.1% respectively. Furthermore we demonstrate noise levels that are low enough to allow for genuine quantum operation in the future.Comment: 5 pages, 4 figure

    Time evolution of a non-singular primordial black hole

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    There is growing notion that black holes may not contain curvature singularities (and that indeed nature in general may abhor such spacetime defects). This notion could have implications on our understanding of the evolution of primordial black holes (PBHs) and possibly on their contribution to cosmic energy. This paper discusses the evolution of a non-singular black hole (NSBH) based on a recent model [1]. We begin with a study of the thermodynamic process of the black hole in this model, and demonstrate the existence of a maximum horizon temperature T_{max}, corresponding to a unique mass value. At this mass value the specific heat capacity C changes signs to positive and the body begins to lose its black hole characteristics. With no loss of generality, the model is used to discuss the time evolution of a primordial black hole (PBH), through the early radiation era of the universe to present, under the assumption that PBHs are non-singular. In particular, we track the evolution of two benchmark PBHs, namely the one radiating up to the end of the cosmic radiation domination era, and the one stopping to radiate currently, and in each case determine some useful features including the initial mass m_{f} and the corresponding time of formation t_{f}. It is found that along the evolutionary history of the universe the distribution of PBH remnant masses (PBH-RM) PBH-RMs follows a power law. We believe such a result can be a useful step in a study to establish current abundance of PBH-MRs.Comment: To appear in Int. J. Mod. Phys.

    The RMS Survey: 6 cm continuum VLA observations towards candidate massive YSOs in the northern hemisphere

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    (Abridged) Context: The Red MSX Source (RMS) survey is an ongoing multi-wavelength observational programme designed to return a large, well-selected sample of massive young stellar objects (MYSOs). We have identified \sim2000 MYSO candidates located throughout the Galaxy by comparing the colours of MSX and 2MASS point sources to those of known MYSOs. Aims: To identify the populations of UCHII regions and PNe within the sample and examine their Galactic distribution. Method: We have conducted high resolution radio continuum observations at 6 cm towards 659 MYSO candidates in the northern hemisphere (10\degr< l < 250\degr) using the VLA. In addition to these targeted observations we present archival data towards a further 315 RMS sources extracted from a previous VLA survey of the inner Galaxy. Results: We find radio emission towards 272 (\sim27% of the observed sample). Using results from other parts of our multi-wavelength survey we separate these RMS-radio associations into two distinct types of objects, classifying 51 as PNe and a further 208 as either compact or UC HII regions. Using this well selected sample of HII regions we estimate their Galactic scale height to be 0.6\degr. Conclusions: Using radio continuum and archival data we have identified 79 PNe and 391 HII regions within the northern RMS catalogue. We estimate the total fraction of contamination by PNe in the RMS sample is of order 10%. The sample of HII regions is probably the best representation to date of the Galactic population of HII regions as a whole.Comment: Accepted for publication in Astronomy and Astrophysics. 15 pages, 9 figures and 5 tables. Full versions of Tables 3, 4 and 5 and Figs. 2, 4 and 7 will only be available via CDS or the RMS website at http:/www.ast.leeds.ac.uk/cgi-bin/RMS/RMS_VLA_IMAGES.cg

    Video-Only Cardiopulmonary Resuscitation Education for High-Risk Families Before Hospital Discharge: A Multicenter Pragmatic Trial

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    BACKGROUND: Cardiopulmonary resuscitation (CPR) training rates in the United States are low, highlighting the need to develop CPR educational approaches that are simpler, with broader dissemination potential. The minimum training required to ensure long-term skill retention remains poorly characterized. We compared CPR skill retention among laypersons randomized to training with video-only (VO; no manikin) with those trained with a video self-instruction kit (VSI; with manikin). We hypothesized that VO training would be noninferior to the VSI approach with respect to chest compression (CC) rate. METHODS AND RESULTS: We performed a prospective, cluster randomized trial of CPR education for family members of patients with high-risk cardiac conditions on hospital cardiac units, using a multicenter pragmatic design. Eight hospitals were randomized to offer either VO or VSI training before discharge using volunteer trainers. CPR skills were assessed 6 months post training. Mean CC rate among those trained with VO compared with those trained with VSI was assessed with a noninferiority margin set at 8 CC per min; as a secondary outcome, mean differences in CC depth were assessed. From February 2012 to May 2015, 1464 subjects were enrolled and 522 subjects completed a skills assessment. The mean CC rates were 87.7 (VO) CC per min and 89.3 (VSI) CC per min; we concluded noninferiority for VO based on a mean difference of -1.6 (90% confidence interval, -5.2 to 2.1). The mean CC depth was 40.2 mm (VO) and 45.8 mm (VSI) with a mean difference of -5.6 (95% confidence interval, -7.6 to -3.7). Results were similar after multivariate regression adjustment. CONCLUSIONS: In this large, prospective trial of CPR skill retention, VO training yielded a noninferior difference in CC rate compared with VSI training. CC depth was greater in the VSI group. These findings suggest a potential trade-off in efforts for broad dissemination of basic CPR skills; VO training might allow for greater scalability and dissemination, but with a potential reduction in CC depth. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01514656

    Dynamic wind farm flow control using free-vortex wake models

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    A novel dynamic economic model-predictive control strategy is presented that improves wind farm power production and reduces the additional demands of wake steering on yaw actuation when compared to an industry state-of-the-art reference controller. The novel controller takes a distributed approach to yaw control optimisation using a free-vortex wake model. An actuator-disc representation of the wind turbine is employed and adapted to the wind-farm scale by modelling secondary effects of wake steering and connecting individual turbines through a directed graph network. The economic model-predictive control problem is solved on a receding horizon using gradient-based optimisation, demonstrating sufficient performance for realising real-time control. The novel controller is tested in a large-eddy simulation environment and compared against a state-of-the-art look-up table approach based on steady-state model optimisation. Under realistic variations in wind direction and wind speed, the novel controller yields additional gains in power production during transients as well as a reduction in yaw actuator usage

    Reinventing grounded theory: some questions about theory, ground and discovery

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    Grounded theory’s popularity persists after three decades of broad-ranging critique. In this article three problematic notions are discussed—‘theory,’ ‘ground’ and ‘discovery’—which linger in the continuing use and development of grounded theory procedures. It is argued that far from providing the epistemic security promised by grounded theory, these notions—embodied in continuing reinventions of grounded theory—constrain and distort qualitative inquiry, and that what is contrived is not in fact theory in any meaningful sense, that ‘ground’ is a misnomer when talking about interpretation and that what ultimately materializes following grounded theory procedures is less like discovery and more akin to invention. The procedures admittedly provide signposts for qualitative inquirers, but educational researchers should be wary, for the significance of interpretation, narrative and reflection can be undermined in the procedures of grounded theory

    Proliferation and estrogen signaling can distinguish patients at risk for early versus late relapse among estrogen receptor positive breast cancers

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    Introduction: We examined if a combination of proliferation markers and estrogen receptor (ER) activity could predict early versus late relapses in ER-positive breast cancer and inform the choice and length of adjuvant endocrine therapy. Methods: Baseline affymetrix gene-expression profiles from ER-positive patients who received no systemic therapy (n = 559), adjuvant tamoxifen for 5 years (cohort-1: n = 683, cohort-2: n = 282) and from 58 patients treated with neoadjuvant letrozole for 3 months (gene-expression available at baseline, 14 and 90 days) were analyzed. A proliferation score based on the expression of mitotic kinases (MKS) and an ER-related score (ERS) adopted from Oncotype DX® were calculated. The same analysis was performed using the Genomic Grade Index as proliferation marker and the luminal gene score from the PAM50 classifier as measure of estrogen-related genes. Median values were used to define low and high marker groups and four combinations were created. Relapses were grouped into time cohorts of 0-2.5, 0-5, 5-10 years. Results: In the overall 10 years period, the proportional hazards assumption was violated for several biomarker groups indicating time-dependent effects. In tamoxifen-treated patients Low-MKS/Low-ERS cancers had continuously increasing risk of relapse that was higher after 5 years than Low-MKS/High-ERS cancers [0 to 10 year, HR 3.36; p = 0.013]. High-MKS/High-ERS cancers had low risk of early relapse [0-2.5 years HR 0.13; p = 0.0006], but high risk of late relapse which was higher than in the High-MKS/Low-ERS group [after 5 years HR 3.86; p = 0.007]. The High-MKS/Low-ERS subset had most of the early relapses [0 to 2.5 years, HR 6.53; p < 0.0001] especially in node negative tumors and showed minimal response to neoadjuvant letrozole. These findings were qualitatively confirmed in a smaller independent cohort of tamoxifen-treated patients. Using different biomarkers provided similar results. Conclusions: Early relapses are highest in highly proliferative/low-ERS cancers, in particular in node negative tumors. Relapses occurring after 5 years of adjuvant tamoxifen are highest among the highly-proliferative/high-ERS tumors although their risk of recurrence is modest in the first 5 years on tamoxifen. These tumors could be the best candidates for extended endocrine therapy

    Design of 280 GHz feedhorn-coupled TES arrays for the balloon-borne polarimeter SPIDER

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    We describe 280 GHz bolometric detector arrays that instrument the balloon-borne polarimeter SPIDER. A primary science goal of SPIDER is to measure the large-scale B-mode polarization of the cosmic microwave background in search of the cosmic-inflation, gravitational-wave signature. 280 GHz channels aid this science goal by constraining the level of B-mode contamination from galactic dust emission. We present the focal plane unit design, which consists of a 16×\times16 array of conical, corrugated feedhorns coupled to a monolithic detector array fabricated on a 150 mm diameter silicon wafer. Detector arrays are capable of polarimetric sensing via waveguide probe-coupling to a multiplexed array of transition-edge-sensor (TES) bolometers. The SPIDER receiver has three focal plane units at 280 GHz, which in total contains 765 spatial pixels and 1,530 polarization sensitive bolometers. By fabrication and measurement of single feedhorns, we demonstrate 14.7^{\circ} FHWM Gaussian-shaped beams with <<1% ellipticity in a 30% fractional bandwidth centered at 280 GHz. We present electromagnetic simulations of the detection circuit, which show 94% band-averaged, single-polarization coupling efficiency, 3% reflection and 3% radiative loss. Lastly, we demonstrate a low thermal conductance bolometer, which is well-described by a simple TES model and exhibits an electrical noise equivalent power (NEP) = 2.6 ×\times 1017^{-17} W/Hz\sqrt{\mathrm{Hz}}, consistent with the phonon noise prediction.Comment: Proceedings of SPIE Astronomical Telescopes + Instrumentation 201
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