7,290 research outputs found
Cell-free synthesis of membrane bound polypeptides
Methods are provided for the utilization of bacterial cell-free extracts in the synthesis of high yields of membrane-associated polypeptides
Core-collapse explosions of Wolf-Rayet stars and the connection to type IIb/Ib/Ic supernovae
We present non-LTE time-dependent radiative-transfer simulations of supernova
(SN) IIb/Ib/Ic spectra and light curves, based on ~1B-energy piston-driven
ejecta, with and without 56Ni, produced from single and binary Wolf-Rayet (W-R)
stars evolved at solar and sub-solar metallicities. Our bolometric light curves
show a 10-day long post-breakout plateau with a luminosity of 1-5x10^7Lsun. In
our 56Ni-rich models, with ~3Msun ejecta masses, this plateau precedes a
20-30-day long re-brightening phase initiated by the outward-diffusing heat
wave powered by radioactive decay at depth. In low ejecta-mass models with
moderate mixing, Gamma-ray leakage starts as early as ~50d after explosion and
causes the nebular luminosity to steeply decline by ~0.02mag/d. Such
signatures, which are observed in standard SNe IIb/Ib/Ic, are consistent with
low-mass progenitors derived from a binary-star population. We propose that the
majority of stars with an initial mass ~<20Msun yield SNe II-P if 'effectively"
single, SNe IIb/Ib/Ic if part of a close binary system, and SN-less black holes
if more massive. Our ejecta, with outer hydrogen mass fractions as low as
~>0.01 and a total hydrogen mass of ~>0.001Msun, yield the characteristic SN
IIb spectral morphology at early times. However, by ~15d after the explosion,
only Halpha may remain as a weak absorption feature. Our binary models,
characterised by helium surface mass fractions of ~>0.85, systematically show
HeI lines during the post-breakout plateau, irrespective of the 56Ni abundance.
Synthetic spectra show a strong sensitivity to metallicity, which offers the
possibility to constrain it directly from SN spectroscopic modelling.Comment: 23 pages, 2 tables, 13 figures, accepted to MNRA
Review of: \u3cem\u3eCarpenter Under Construction: The Story of Don Plank\u3c/em\u3e—Diane Freed
Carpenter Under Construction is the story of Don Plank’s life, written by his youngest daughter. It briefly touches on his early life and moves through major life events. About half of the book covers the busy later years in life when he and his second wife moved from mission to mission in various support roles. Don was a good carpenter, but Freed puts more emphasis on what God built Don to be rather than on what Don himself built during his long life. [First paragraph.
Our Space: Being a Responsible Citizen of the Digital World
Our Space is a set of curricular materials designed to encourage high school students to reflect on the ethical dimensions of their participation in new media environments. Through role-playing activities and reflective exercises, students are asked to consider the ethical responsibilities of other people, and whether and how they behave ethically themselves online. These issues are raised in relation to five core themes that are highly relevant online: identity, privacy, authorship and ownership, credibility, and participation.Our Space was co-developed by The Good Play Project and Project New Media Literacies (established at MIT and now housed at University of Southern California's Annenberg School for Communications and Journalism). The Our Space collaboration grew out of a shared interest in fostering ethical thinking and conduct among young people when exercising new media skills
A WATFIV Implementation and Evaluation of a Rubric for the Reduction of Extraneous Variability in the Observed Frequency of Infant State Transitions
Symptoms associated with victimization in patients with schizophrenia and related disorders
Background: Patients with psychoses have an increased risk of becoming victims of violence. Previous studies have suggested that higher symptom levels are associated with a raised risk of becoming a victim of physical violence. There has been, however, no evidence on the type of symptoms that are linked with an increased risk of recent victimization. Methods: Data was taken from two studies on involuntarily admitted patients, one national study in England and an international one in six other European countries. In the week following admission, trained interviewers asked patients whether they had been victims of physical violence in the year prior to admission, and assessed symptoms on the Brief Psychiatric Rating Scale (BPRS). Only patients with a diagnosis of schizophrenia or related disorders (ICD-10 F20–29) were included in the analysis which was conducted separately for the two samples. Symptom levels assessed on the BPRS subscales were tested as predictors of victimization. Univariable and multivariable logistic regression models were fitted to estimate adjusted odds ratios. Results: Data from 383 patients in the English sample and 543 patients in the European sample was analysed. Rates of victimization were 37.8% and 28.0% respectively. In multivariable models, the BPRS manic subscale was significantly associated with victimization in both samples. Conclusions: Higher levels of manic symptoms indicate a raised risk of being a victim of violence in involuntary patients with schizophrenia and related disorders. This might be explained by higher activity levels, impaired judgement or poorer self-control in patients with manic symptoms. Such symptoms should be specifically considered in risk assessments
Wolbachia and DNA barcoding insects: patterns, potential and problems
Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein – wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor – for which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region
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