359 research outputs found

    HOPS 383: An Outbursting Class 0 Protostar in Orion

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    We report the dramatic mid-infrared brightening between 2004 and 2006 of HOPS 383, a deeply embedded protostar adjacent to NGC 1977 in Orion. By 2008, the source became a factor of 35 brighter at 24 microns with a brightness increase also apparent at 4.5 microns. The outburst is also detected in the submillimeter by comparing APEX/SABOCA to SCUBA data, and a scattered-light nebula appeared in NEWFIRM K_s imaging. The post-outburst spectral energy distribution indicates a Class 0 source with a dense envelope and a luminosity between 6 and 14 L_sun. Post-outburst time-series mid- and far-infrared photometry shows no long-term fading and variability at the 18% level between 2009 and 2012. HOPS 383 is the first outbursting Class 0 object discovered, pointing to the importance of episodic accretion at early stages in the star formation process. Its dramatic rise and lack of fading over a six-year period hint that it may be similar to FU Ori outbursts, although the luminosity appears to be significantly smaller than the canonical luminosities of such objects.Comment: Accepted by ApJ Letters, 6 pages, 4 figures; v2 has an updated email address for the lead autho

    Update on the Surgical Trial in Lobar Intracerebral Haemorrhage (STICH II):Statistical analysis plan

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    <p>Abstract</p> <p>Background</p> <p>Previous studies had suggested that the outcome for patients with spontaneous lobar intracerebral haemorrhage (ICH) and no intraventricular haemorrhage (IVH) might be improved with early evacuation of the haematoma. The Surgical Trial in Lobar Intracerebral Haemorrhage (STICH II) set out to establish whether a policy of earlier surgical evacuation of the haematoma in selected patients with spontaneous lobar ICH would improve outcome compared to a policy of initial conservative treatment. It is an international, multi-centre, prospective randomised parallel group trial of early surgery in patients with spontaneous lobar ICH. Outcome is measured at six months via a postal questionnaire.</p> <p>Results</p> <p>Recruitment to the study began on 27 November 2006 and closed on 15 August 2012 by which time 601 patients had been recruited. The protocol was published in <it>Trials</it> (<url>http://www.trialsjournal.com/content/12/1/124/</url>). This update presents the analysis plan for the study without reference to the unblinded data. The trial data will not be unblinded until after follow-up is completed in early 2013. The main trial results will be presented in spring 2013 with the aim to publish in a peer-reviewed journal at the same time.</p> <p>Conclusion</p> <p>The data from the trial will provide evidence on the benefits and risks of early surgery in patients with lobar ICH.</p> <p>Trial registration</p> <p>ISRCTN: ISRCTN22153967</p

    Obese endometrial cancer survivors\u27 perceptions of weight loss strategies and characteristics that may influence participation in behavioral interventions

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    We aimed to evaluate obese endometrial cancer (EC) survivors\u27 perceptions of weight loss barriers and previously attempted weight loss methods and to identify characteristics that predicted willingness to enroll in a behavioral intervention trial. We administered a 27-question baseline survey at an academic institution to EC survivors with body mass index ā‰„ 30 kg/

    The Herschel Orion Protostar Survey: Luminosity and Envelope Evolution

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    The Herschel Orion Protostar Survey obtained well-sampled 1.2ā€“870 Ī¼m spectral energy distributions (SEDs) of over 300 protostars in the Orion molecular clouds, home to most of the young stellar objects (YSOs) in the nearest 500 pc. We plot the bolometric luminosities and temperatures for 330 Orion YSOs, 315 of which have bolometric temperatures characteristic of protostars. The histogram of the bolometric temperature is roughly flat; 29% of the protostars are in Class 0. The median luminosity decreases by a factor of four with increasing bolometric temperature; consequently, the Class 0 protostars are systematically brighter than the Class I protostars, with a median luminosity of 2.3 L_ā˜‰ as opposed to 0.87 L_ā˜‰. At a given bolometric temperature, the scatter in luminosities is three orders of magnitude. Using fits to the SEDs, we analyze how the luminosities corrected for inclination and foreground reddening relate to the mass in the inner 2500 au of the best-fit model envelopes. The histogram of the envelope mass is roughly flat, while the median-corrected luminosity peaks at 15 L_ā˜‰ for young envelopes and falls to 1.7 L_ā˜‰ for late-stage protostars with remnant envelopes. The spread in luminosity at each envelope mass is three orders of magnitude. Envelope masses that decline exponentially with time explain the flat mass histogram and the decrease in luminosity, while the formation of a range of stellar masses explains the dispersion in luminosity

    A Herschel and APEX Census of the Reddest Sources in Orion: Searching for the Youngest Protostars

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    We perform a census of the reddest, and potentially youngest, protostars in the Orion molecular clouds using data obtained with the PACS instrument on board the Herschel Space Observatory and the LABOCA and SABOCA instruments on APEX as part of the Herschel Orion Protostar Survey (HOPS). A total of 55 new protostar candidates are detected at 70 Ī¼m and 160 Ī¼m that are either too faint (m_(24) > 7 mag) to be reliably classified as protostars or undetected in the Spitzer/MIPS 24 Ī¼m band. We find that the 11 reddest protostar candidates with log Ī»F_Ī»70/Ī»F_Ī»24 > 1.65 are free of contamination and can thus be reliably explained as protostars. The remaining 44 sources have less extreme 70/24 colors, fainter 70 Ī¼m fluxes, and higher levels of contamination. Taking the previously known sample of Spitzer protostars and the new sample together, we find 18 sources that have log Ī»F_Ī»70/Ī»F_Ī»24 > 1.65; we name these sources "PACS Bright Red sources," or PBRs. Our analysis reveals that the PBR sample is composed of Class 0 like sources characterized by very red spectral energy distributions (SEDs; T_(bol) 0.6%). Modified blackbody fits to the SEDs provide lower limits to the envelope masses of 0.2-2 M_ā˜‰ and luminosities of 0.7-10 L_ā˜‰. Based on these properties, and a comparison of the SEDs with radiative transfer models of protostars, we conclude that the PBRs are most likely extreme Class 0 objects distinguished by higher than typical envelope densities and hence, high mass infall rates

    Human gene therapy for RPE65 isomerase deficiency activates the retinoid cycle of vision but with slow rod kinetics

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    The RPE65 gene encodes the isomerase of the retinoid cycle, the enzymatic pathway that underlies mammalian vision. Mutations in RPE65 disrupt the retinoid cycle and cause a congenital human blindness known as Leber congenital amaurosis (LCA). We used adeno-associated virus-2-based RPE65 gene replacement therapy to treat three young adults with RPE65-LCA and measured their vision before and up to 90 days after the intervention. All three patients showed a statistically significant increase in visual sensitivity at 30 days after treatment localized to retinal areas that had received the vector. There were no changes in the effect between 30 and 90 days. Both cone- and rod-photoreceptor-based vision could be demonstrated in treated areas. For cones, there were increases of up to 1.7 log units (i.e., 50 fold); and for rods, there were gains of up to 4.8 log units (i.e., 63,000 fold). To assess what fraction of full vision potential was restored by gene therapy, we related the degree of light sensitivity to the level of remaining photoreceptors within the treatment area. We found that the intervention could overcome nearly all of the loss of light sensitivity resulting from the biochemical blockade. However, this reconstituted retinoid cycle was not completely normal. Resensitization kinetics of the newly treated rods were remarkably slow and required 8 h or more for the attainment of full sensitivity, compared with \u3c1 h in normal eyes. Cone-sensitivity recovery time was rapid. These results demonstrate\u3edramatic, albeit imperfect, recovery of rod- and cone-photoreceptor-based vision after RPE65 gene therapy

    Effect of thermal treatment on the growth, structure and luminescence of nitride-passivated silicon nanoclusters

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    Silicon nanoclusters (Si-ncs) embedded in silicon nitride films have been studied to determine the effects that deposition and processing parameters have on their growth, luminescent properties, and electronic structure. Luminescence was observed from Si-ncs formed in silicon-rich silicon nitride films with a broad range of compositions and grown using three different types of chemical vapour deposition systems. Photoluminescence (PL) experiments revealed broad, tunable emissions with peaks ranging from the near-infrared across the full visible spectrum. The emission energy was highly dependent on the film composition and changed only slightly with annealing temperature and time, which primarily affected the emission intensity. The PL spectra from films annealed for duration of times ranging from 2 s to 2 h at 600 and 800Ā°C indicated a fast initial formation and growth of nanoclusters in the first few seconds of annealing followed by a slow, but steady growth as annealing time was further increased. X-ray absorption near edge structure at the Si K- and L3,2-edges exhibited composition-dependent phase separation and structural re-ordering of the Si-ncs and silicon nitride host matrix under different post-deposition annealing conditions and generally supported the trends observed in the PL spectra

    Early surgery versus initial conservative treatment in patients with spontaneous supratentorial lobar intracerebral haematomas (STICH II):a randomised trial

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    SummaryBackgroundThe balance of risk and benefit from early neurosurgical intervention for conscious patients with superficial lobar intracerebral haemorrhage of 10ā€“100 mL and no intraventricular haemorrhage admitted within 48 h of ictus is unclear. We therefore tested the hypothesis that early surgery compared with initial conservative treatment could improve outcome in these patients.MethodsIn this international, parallel-group trial undertaken in 78 centres in 27 countries, we compared early surgical haematoma evacuation within 12 h of randomisation plus medical treatment with initial medical treatment alone (later evacuation was allowed if judged necessary). An automatic telephone and internet-based randomisation service was used to assign patients to surgery and initial conservative treatment in a 1:1 ratio. The trial was not masked. The primary outcome was a prognosis-based dichotomised (favourable or unfavourable) outcome of the 8 point Extended Glasgow Outcome Scale (GOSE) obtained by questionnaires posted to patients at 6 months. Analysis was by intention to treat. This trial is registered, number ISRCTN22153967.Findings307 of 601 patients were randomly assigned to early surgery and 294 to initial conservative treatment; 298 and 291 were followed up at 6 months, respectively; and 297 and 286 were included in the analysis, respectively. 174 (59%) of 297 patients in the early surgery group had an unfavourable outcome versus 178 (62%) of 286 patients in the initial conservative treatment group (absolute difference 3Ā·7% [95% CI āˆ’4Ā·3 to 11Ā·6], odds ratio 0Ā·86 [0Ā·62 to 1Ā·20]; p=0Ā·367).InterpretationThe STICH II results confirm that early surgery does not increase the rate of death or disability at 6 months and might have a small but clinically relevant survival advantage for patients with spontaneous superficial intracerebral haemorrhage without intraventricular haemorrhage.FundingUK Medical Research Council

    Phenotype-specific effect of chromosome 1q21.1 rearrangements and GJA5 duplications in 2436 congenital heart disease patients and 6760 controls

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    Recurrent rearrangements of chromosome 1q21.1 that occur via non-allelic homologous recombination have been associated with variable phenotypes exhibiting incomplete penetrance, including congenital heart disease (CHD). However, the gene or genes within the āˆ¼1 Mb critical region responsible for each of the associated phenotypes remains unknown. We examined the 1q21.1 locus in 948 patients with tetralogy of Fallot (TOF), 1488 patients with other forms of CHD and 6760 ethnically matched controls using single nucleotide polymorphism genotyping arrays (Illumina 660W and Affymetrix 6.0) and multiplex ligation-dependent probe amplification. We found that duplication of 1q21.1 was more common in cases of TOF than in controls [odds ratio (OR) 30.9, 95% confidence interval (CI) 8.9-107.6); P = 2.2 Ɨ 10āˆ’7], but deletion was not. In contrast, deletion of 1q21.1 was more common in cases of non-TOF CHD than in controls [OR 5.5 (95% CI 1.4-22.0); P = 0.04] while duplication was not. We also detected rare (n = 3) 100-200 kb duplications within the critical region of 1q21.1 in cases of TOF. These small duplications encompassed a single gene in common, GJA5, and were enriched in cases of TOF in comparison to controls [OR = 10.7 (95% CI 1.8-64.3), P = 0.01]. These findings show that duplication and deletion at chromosome 1q21.1 exhibit a degree of phenotypic specificity in CHD, and implicate GJA5 as the gene responsible for the CHD phenotypes observed with copy number imbalances at this locu

    Phenotype-specific effect of chromosome 1q21.1 rearrangements and GJA5 duplications in 2436 congenital heart disease patients and 6760 controls

    Get PDF
    Recurrent rearrangements of chromosome 1q21.1 that occur via non-allelic homologous recombination have been associated with variable phenotypes exhibiting incomplete penetrance, including congenital heart disease (CHD). However, the gene or genes within the āˆ¼1 Mb critical region responsible for each of the associated phenotypes remains unknown. We examined the 1q21.1 locus in 948 patients with tetralogy of Fallot (TOF), 1488 patients with other forms of CHD and 6760 ethnically matched controls using single nucleotide polymorphism genotyping arrays (Illumina 660W and Affymetrix 6.0) and multiplex ligation-dependent probe amplification. We found that duplication of 1q21.1 was more common in cases of TOF than in controls [odds ratio (OR) 30.9, 95% confidence interval (CI) 8.9ā€“107.6); P = 2.2 Ɨ 10āˆ’7], but deletion was not. In contrast, deletion of 1q21.1 was more common in cases of non-TOF CHD than in controls [OR 5.5 (95% CI 1.4ā€“22.0); P = 0.04] while duplication was not. We also detected rare (n = 3) 100ā€“200 kb duplications within the critical region of 1q21.1 in cases of TOF. These small duplications encompassed a single gene in common, GJA5, and were enriched in cases of TOF in comparison to controls [OR = 10.7 (95% CI 1.8ā€“64.3), P = 0.01]. These findings show that duplication and deletion at chromosome 1q21.1 exhibit a degree of phenotypic specificity in CHD, and implicate GJA5 as the gene responsible for the CHD phenotypes observed with copy number imbalances at this locus
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