488 research outputs found

    A powerful bursting radio source towards the Galactic Centre

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    Transient astronomical sources are typically powered by compact objects and usually signify highly explosive or dynamic events. While radio astronomy has an impressive record of obtaining high time resolution observations, usually it is achieved in quite narrow fields-of-view. Consequently, the dynamic radio sky is poorly sampled, in contrast to the situation in the X- and gamma-ray bands in which wide-field instruments routinely detect transient sources. Here we report a new transient source, GCRT J1745-3009, detected in 2002 during a moderately wide-field radio transient monitoring program of the Galactic center (GC) region at 0.33 GHz. The characteristics of its bursts are unlike those known for any other class of radio transient. If located in or near the GC, its brightness temperature (~10^16 K) and the implied energy density within GCRT J1745-3009 vastly exceeds that observed in most other classes of radio astronomical sources, and is consistent with coherent emission processes rarely observed. We conclude that GCRT J1745-3009 is the first member of a new class of radio transient sources, the first of possibly many new classes to be identified through current and upcoming radio surveys.Comment: 16 pages including 3 figures. Appears in Nature, 3 March 200

    GCRT J1742-3001: A New Radio Transient Towards the Galactic Center

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    We report the detection of a new transient radio source, GCRT J1742-3001, located ~1 degree from the Galactic center. The source was detected ten times from late 2006 to 2007 May in our 235 MHz transient monitoring program with the Giant Metrewave Radio Telescope (GMRT). The radio emission brightened in about one month, reaching a peak observed flux density of ~100 mJy on 2007 January 28, and decaying to ~50 mJy by 2007 May when our last monitoring observation was made. Two additional faint, isolated 235 MHz detections were made in mid-2006, also with the GMRT. GCRT J1742-3001 is unresolved at each epoch, with typical resolutions of ~20 arcsec x 10 arcsec. No polarization information is available from the observations. Based on nondetections in observations obtained simultaneously at 610 MHz, we deduce that the spectrum of GCRT J1742-3001 is very steep, with a spectral index less than about -2. Follow-up radio observations in 2007 September at 330 MHz and 1.4 GHz, and in 2008 February at 235 MHz yielded no detections. No X-ray counterpart is detected in a serendipitous observation obtained with the X-ray telescope aboard the Swift satellite during the peak of the radio emission in early 2007. We consider the possibilities that GCRT J1742-3001 is either a new member of an existing class of radio transients, or is representative of a new class having no associated X-ray emission.Comment: 19 pages, 3 figures, submitted to Ap

    A Randomized Controlled Trial of an Outpatient Protocol for Transitioning Children from Tube to Oral Feeding: No Need for Amitriptyline.

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    ObjectiveTo assess the role of amitriptyline in the effectiveness of an outpatient protocol for weaning medically complicated children from tube to oral feeding.Study designTwenty-one children seen in multidisciplinary outpatient feeding teams across 4 sites were recruited to a randomized placebo-controlled trial of a 6-month outpatient treatment protocol with behavioral, oral-motor, nutrition, and medication components.ResultsAll of the children who completed the 6-month program (73%) were weaned to receive only oral feeding, regardless of group assignment. The transition from tube to oral feeding resulted in decreases in body mass index percentile and pain, some improvements in quality of life, and no statistically significant changes in cost.ConclusionsAmitriptyline is not a key component of this otherwise effective outpatient, interdisciplinary protocol for weaning children from tube to oral feeding.Trial registrationClinicalTrials.gov: NCT01206478

    iKanEat: Protocol for a randomized controlled trial of megestrol as a component of a pediatric tube weaning protocol

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    Background Although tube feeding routinely saves the lives of children who do not eat by mouth, chronic tube feeding can be a burden to patients, caregivers, and families. Very few randomized trials exist regarding the best methods for weaning children from their feeding tubes. Methods The current paper describes a randomized controlled trial of an empirically supported outpatient treatment protocol for moving children from tube to oral eating called iKanEat. Specifically, we describe the methods of randomized double-blind, placebo-controlled trial which includes a 4-week course of megestrol, the only medication used in the iKanEat protocol, to determine whether the addition of megestrol results in improved child outcomes. The primary and secondary aims are to assess the safety and efficacy of megestrol as part of the iKanEat protocol. The third aim is to provide critical information about the impact of the transition from tube to oral feeding on parent stress and parent and child quality of life. Discussion This trial will provide data regarding whether megestrol is a safe and effective component of the iKanEat tube weaning protocol, as well as important data on how the tube weaning process impacts parent stress and parent and child quality of life

    Competing risks of death in women treated with adjuvant aromatase inhibitors for early breast cancer on NCIC CTG MA.27

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    Baseline patient and tumor characteristics differentially affected type of death in the MA.17 placebo-controlled letrozole trial where cardiovascular death was not separately identified. The MA.27 trial allowed competing risks analysis of breast cancer (BC), cardiovascular, and other type (OT) of death. MA.27 was a phase III adjuvant breast cancer trial of exemestane versus anastrozole. Effects of baseline patient and tumor characteristics were tested for whether factors were associated with (1) all cause mortality and (2) cause-specific mortality. We also fit step-wise forward cause-specific-adjusted models. 7576 women (median age 64 years; 5417 (72 %) < 70 years and 2159 (28 %) ≄ 70 years) were enrolled and followed for median 4.1 years. The 432 deaths comprised 187 (43 %) BC, 66 (15 %) cardiovascular, and 179 (41 %) OT. Five baseline factors were differentially associated with type of death. Older patients had greater BC (p = 0.03), cardiovascular (p < 0.001), and other types (p < 0.001) of mortality. Patients with pre-existing cardiovascular history had worse cardiovascular mortality (p < 0.001); those with worse ECOG performance status had worse OT mortality (p < 0.001). Patients with T1 tumors (p < 0.001) and progesterone receptor positive had less BC mortality (p < 0.001). Fewer BC deaths occurred with node-negative disease (p < 0.001), estrogen receptor-positive tumors (p = 0.001), and without adjuvant chemotherapy (p = 0.005); worse cardiovascular mortality (p = 0.01), with trastuzumab; worse OT mortality, for non-whites (p = 0.03) and without adjuvant radiotherapy (p = 0.003). Overall, 57 % of deaths in MA.27 AI-treated patients were non-breast cancer related. Baseline patient and tumor characteristics differentially affected type of death with women 70 or older experiencing more non-breast cancer death

    Images of survival, stories of destruction: Nuclear war on British screens from 1945 to the early 1960s

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    This article discusses a range of depictions and discussions of nuclear war, which appeared on British screens in the first half of the Cold War, in order to understand the changing way nuclear weapons were viewed within British culture. Using such screened images to understand how nuclear war was constructed and represented within British culture, the article argues that the hydrogen bomb, not the atomic bomb, was the true harbinger of the nuclear revolution that transformed cultural understandings of warfare and destruction. Although the atomic bomb created a great deal of anxiety within British popular culture, representations of atomic attack elided atomic destruction with that experienced in 1939-45, emphasising the 'survivability' of atomic war. In the thermonuclear era, the Second World War could not undertake the same symbolic work. The image of the city-destroying bomb was an imaginative as well as technological step-change. Screened representations stressed that a thermonuclear war would literally end the world. As such, they preceded, and indeed provided the cultural climate for, the rise of the Campaign for Nuclear Disarmament (CND). The Campaign exploited and further popularised this idea of the apocalyptic nuclear war as a key aspect of its political and moral standpoint. The article concludes, however, that the cultural hegemony of this vision of nuclear war equally helped underpin notions of nuclear deterrence. The basic assumptions about the nature of nuclear war constructed and circulated on British screens therefore formed part of CND's 'cultural' victory but the article also explains why this did not translate into the political realm. © Edinburgh University Press

    What the disjunctivist is right about

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    There is a traditional conception of sensory experience on which the experiences one has looking at, say, a cat could be had by someone merely hallucinating a cat. Disjunctivists take issue with this conception on the grounds that it does not enable us to understand how perceptual knowledge is possible. In particular, they think, it does not explain how it can be that experiences gained in perception enable us to be in ‘cognitive contact’ with objects and facts. I develop this chal- lenge to the traditional conception and then show that it is possible to accommo- date an adequate account of cognitive contact in keeping with the traditional conception. One upshot of the discussion is that experiences do not bear the explanatory burden placed upon them by disjunctivists

    Multiplex Cytological Profiling Assay to Measure Diverse Cellular States

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    Computational methods for image-based profiling are under active development, but their success hinges on assays that can capture a wide range of phenotypes. We have developed a multiplex cytological profiling assay that “paints the cell” with as many fluorescent markers as possible without compromising our ability to extract rich, quantitative profiles in high throughput. The assay detects seven major cellular components. In a pilot screen of bioactive compounds, the assay detected a range of cellular phenotypes and it clustered compounds with similar annotated protein targets or chemical structure based on cytological profiles. The results demonstrate that the assay captures subtle patterns in the combination of morphological labels, thereby detecting the effects of chemical compounds even though their targets are not stained directly. This image-based assay provides an unbiased approach to characterize compound- and disease-associated cell states to support future probe discovery
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