795 research outputs found

    Portable light detection system for the blind

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    System can be used to detect "ready" light on automatic cooking device, to tell if lights are on for visitors, or to tell whether it is daylight or dark outside. Device is actuated like flashlight. Light impinging on photo cell activates transistor which energizes buzzer to indicate presence of light

    The Future of Micro-grids in Ecuador

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    An analysis is made on the development of power lines worldwide and that offer the approaches of the impacts that are generated in the economic and environmental, which justify the application of smart grids in Ecuador, as an effective way to raise the efficiency of the electric power service and to achieve a more efficient use of the energy that is generated by showing the different technologies used in electricity generation where renewable energy sources are incorporated. A comparative analysis of how the installed generation power has been increasing until 2016 is shown

    Entecavir versus lamivudine for patients with HBeAg-negative chronic hepatitis B

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    BACKGROUND: Entecavir is a potent and selective antiviral agent that has demonstrated efficacy in phase 2 studies in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B. METHODS: In this phase 3, double-blind trial, we randomly assigned 648 patients with HBeAg-negative chronic hepatitis B who had not previously been treated with a nucleoside analogue to receive 0.5 mg of entecavir or 100 mg of lamivudine once daily for a minimum of 52 weeks. The primary efficacy end point was histologic improvement (a decrease by at least two points in the Knodell necroinflammatory score, without worsening of fibrosis). RESULTS: Histologic improvement after 48 weeks of treatment occurred in 208 of 296 patients in the entecavir group who had adequate baseline liver-biopsy specimens that could be evaluated (70 percent), as compared with 174 of 287 such patients in the lamivudine group (61 percent, P=0.01). More patients in the entecavir group than in the lamivudine group had undetectable serum hepatitis B virus (HBV) DNA levels according to a polymerase-chain- reaction assay (90 percent vs. 72 percent, P<0.001) and normalization of alanine aminotransferase levels (78 percent vs. 71 percent, P = 0.045). The mean reduction in serum HBV DNA levels from baseline to week 48 was greater with entecavir than with lamivudine (5.0 vs. 4.5 log [on a base-10 scale] copies per milliliter, P<0.001). There was no evidence of resistance to entecavir. Safety and adverse-event profiles were similar in the two groups. CONCLUSIONS: Among patients with HBeAg-negative chronic hepatitis B who had not previously been treated with a nucleoside analogue, the rates of histologic improvement, virologic response, and normalization of alanine aminotransferase levels were significantly higher at 48 weeks with entecavir than with lamivudine. The safety profile of the two agents was similar, and there was no evidence of viral resistance to entecavir. Copyright © 2006 Massachusetts Medical Society.published_or_final_versio

    Warped diffusive radio halo around the quiescent spiral edge-on galaxy NGC 4565

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    Context. Cosmic rays play a pivotal role in launching galactic winds, particularly in quiescently star-forming galaxies where the hot gas alone is not sufficient to drive a wind. Except for the Milky Way, not much is known about the transport of cosmic rays in galaxies. Aims. In this Letter, we present low-frequency observations of the nearby edge-on spiral galaxy NGC 4565 using the LOw-Frequency ARray (LOFAR). With our deep 144 MHz observations, we obtain a clean estimate of the emission originating from old cosmic-ray electrons (CRe), which is almost free from contamination by thermal emission. Methods. We measured vertical profiles of the non-thermal radio continuum emission that we fitted with Gaussian and exponential functions. The different profile shapes correspond to 1D cosmic-ray transport models of pure diffusion and advection, respectively. Results. We detect a warp in the radio continuum that is reminiscent of the previously known H 

    TRH: Pathophysiologic and clinical implications

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    Thyrotropin releasing hormone is thought to be a tonic stimulator of the pituitary TSH secretion regulating the setpoint of the thyrotrophs to the suppressive effect of thyroid hormones. The peptide stimulates the release of normal and elevated prolactin. ACTH and GH may increase in response to exogenous TRH in pituitary ACTH and GH hypersecretion syndromes and in some extrapituitary diseases. The pathophysiological implications of extrahypothalamic TRH in humans are essentially unknown. The TSH response to TRH is nowadays widely used as a diganostic amplifier in thyroid diseases being suppressed in borderline and overt hyperthyroid states and increased in primary thyroid failure. In hypothyroid states of hypothalamic origin, TSH increases in response to exogenous TRH often with a delayed and/or exaggerated time course. But in patients with pituitary tumors and suprasellar extension TSH may also respond to TRH despite secondary hypothyroidism. This TSH increase may indicate a suprasellar cause for the secondary hypothyroidism, probably due to portal vessel occlusion. The TSH released in these cases is shown to be biologically inactive

    A LOFAR study of non-merging massive galaxy clusters

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    Centrally located diffuse radio emission has been observed in both merging and non-merging galaxy clusters. Depending on their morphology and size, we distinguish between giant radio haloes, which occur predominantly in merging clusters, and mini haloes, which are found in non-merging, cool-core clusters. In recent years, cluster-scale radio emission has also been observed in clusters with no sign of major mergers, showing that our knowledge of the mechanisms that lead to particle acceleration in the intra-cluster medium (ICM) is still incomplete. Low-frequency sensitive observations are required to assess whether the emission discovered in these few cases is common in galaxy clusters or not. With this aim, we carried out a campaign of observations with the LOw Frequency ARay (LOFAR) in the frequency range 120-168 MHz of nine massive clusters selected from the Planck SZ catalogue, which had no sign of major mergers. In this paper, we discuss the results of the observations that have led to the largest cluster sample studied within the LOFAR Two-metre Sky Survey, and we present Chandra X-ray data used to investigate the dynamical state of the clusters, verifying that the clusters are currently not undergoing major mergers, and to search for traces of minor or off-axis mergers. We discover large-scale steep-spectrum emission around mini haloes in the cool-core clusters PSZ1G139.61+24 and RXJ1720.1+2638, which is not observed around the mini halo in the non-cool-core cluster A1413. We also discover a new 570 kpc-halo in the non-cool-core cluster RXCJ0142.0+2131. We derived new upper limits to the radio power for clusters in which no diffuse radio emission was found, and we discuss the implication of our results to constrain the cosmic-ray energy budget in the ICM. We conclude that radio emission in non-merging massive clusters is not common at the sensitivity level reached by our observations and that no clear connection with the cluster dynamical state is observed. Our results might indicate that the sloshing of a dense cool core could trigger particle acceleration on larger scales and generate steep-spectrum radio emission

    Evolutionary phases of merging clusters as seen by LOFAR

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    Massive, merging galaxy clusters often host giant, diffuse radio sources that arise from shocks and turbulence; hence, radio observations can be useful for determining the merger state of a cluster. In preparation for a larger study, we selected three clusters - Abell 1319, Abell 1314, and RXC J1501.3+4220 (Z7215) - making use of the new LOFAR Two-Metre Sky Survey (LoTSS) at 120-168 MHz, and together with archival data, show that these clusters appear to be in pre-merging, merging, and post-merging states, respectively. We argue that Abell 1319 is likely in its pre-merging phase, where three separate cluster components are about to merge. There are no radio haloes nor radio relics detected in this system. Abell 1314 is a highly disturbed, low-mass cluster that is likely in the process of merging. This low-mass system does not show a radio halo, however, we argue that the merger activates mechanisms that cause electron re-acceleration in the large 800 kpc radio tail associated with IC 711. In the cluster Z7215 we discover diffuse radio emission at the cluster centre, and we classify this emission as a radio halo, although it is dimmer and smaller than expected by the radio halo power versus cluster mass correlation. We suggest that the disturbed cluster Z7215 is in its post-merging phase. Systematic studies of this kind over a larger sample of clusters observed with LoTSS will help to constrain the timescales involved in turbulent re-acceleration and the subsequent energy losses of the underlying electrons

    Context-dependent conservation responses to emerging wildlife diseases

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    Emerging infectious diseases pose an important threat to wildlife. While established protocols exist for combating outbreaks of human and agricultural pathogens, appropriate management actions before, during, and after the invasion of wildlife pathogens have not been developed. We describe stage-specific goals and management actions that minimize disease impacts on wildlife, and the research required to implement them. Before pathogen arrival, reducing the probability of introduction through quarantine and trade restrictions is key because prevention is more cost effective than subsequent responses. On the invasion front, the main goals are limiting pathogen spread and preventing establishment. In locations experiencing an epidemic, management should focus on reducing transmission and disease, and promoting the development of resistance or tolerance. Finally, if pathogen and host populations reach a stable stage, then recovery of host populations in the face of new threats is paramount. Successful management of wildlife disease requires risk-taking, rapid implementation, and an adaptive approach."Funding was provided by the US National Science Foundation (grants EF-0914866, DGE-0741448, DEB-1115069, DEB-1336290) and the National Institutes of Health (grant 1R010AI090159)."https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/14024
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