1,612 research outputs found
Type IIn supernovae at z ~ 2 from archival data
Supernovae have been confirmed to redshift z ~ 1.7 for type Ia (thermonuclear
detonation of a white dwarf) and to z ~ 0.7 for type II (collapse of the core
of the star). The subclass type IIn supernovae are luminous core-collapse
explosions of massive stars and, unlike other types, are very bright in the
ultraviolet, which should enable them to be found optically at redshifts z ~ 2
and higher. In addition, the interaction of the ejecta with circumstellar
material creates strong, long-lived emission lines that allow spectroscopic
confirmation of many events of this type at z ~ 2 for 3 - 5 years after
explosion. Here we report three spectroscopically confirmed type IIn
supernovae, at redshifts z = 0.808, 2.013 and 2.357, detected in archival data
using a method designed to exploit these properties at z ~ 2. Type IIn
supernovae directly probe the formation of massive stars at high redshift. The
number found to date is consistent with the expectations of a locally measured
stellar initial mass function, but not with an evolving initial mass function
proposed to explain independent observations at low and high redshift.Comment: 8 pages, 2 figures, includes supplementary informatio
Professional Development and the Informal Curriculum in End-of-Life Care
Although professionalism has emerged as a key competency for today’s physicians, there exists little insight into how best to teach medical students the relevant skills or instill in them the commitment required to practice according to the highest professional standards. Ten UCSF medical students were interviewed at three time points (second, third, and fourth years of school). Interviews focused on students’ learning and development regarding end-of-life care (EOLC). Students described varying steps in their professional development from their second to fourth years of school, including feeling confused about the definition of professionalism and integrating their personal and professional identities. In addition to professional development, four other themes contributed to the development of medical student understanding of how to provide EOLC as a professional: (1) curricular discordance, (2) role models, (3) the tightrope between trained versus human reactions, and (4) ethical dilemmas. These five themes represent dilemmas that students often learned how to respond to over the course of school. Professional development in EOLC required the acquisition of skills necessary to balance the tension between and navigate conflicting messages present in medical student training
Author Correction: Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases.
Emmanuelle Souzeau, who contributed to analysis of data, was inadvertently omitted from the author list in the originally published version of this Article. This has now been corrected in both the PDF and HTML versions of the Article
Evidence That Lipopolisaccharide May Contribute to the Cytokine Storm and Cellular Activation in Patients with Visceral Leishmaniasis
Visceral leishmaniasis (VL) affects organs rich in lymphocytes, being characterized by intense Leishmania-induced T-cell depletion and reduction in other hematopoietic cells. In other infectious and non-infectious diseases in which the immune system is affected, such as HIV-AIDS and inflammatory bowel disease, damage to gut-associated lymphocyte tissues occurs, enabling luminal bacteria to enter into the circulation. Lipopolisaccharide (LPS) is a bacterial product that stimulates macrophages, leading to the production of pro-inflammatory cytokines and other soluble factors such as MIF, which in turn activate lymphocytes. Continuous and exaggerated stimulation causes exhaustion of the T-cell compartment, contributing to immunosuppression
Breast clinic and life style study BLLISS
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Evaluation of corrective measures implemented for the preventive conservation of fresco paintings in Ariadne s house (Pompeii, Italy)
BACKGROUND:
A microclimate monitoring study was conducted in 2008 aimed at assessing the conservation risks affecting the valuable wall paintings decorating Ariadne s House (Pompeii, Italy). It was found that thermohygrometric conditions were very unfavorable for the conservation of frescoes. As a result, it was decided to implement corrective measures, and the transparent polycarbonate sheets covering three rooms (one of them delimited by four walls and the others composed of three walls) were replaced by opaque roofs. In order to examine the effectiveness of this measure, the same monitoring system comprised by 26 thermohygrometric probes was installed again in summer 2010. Data recorded in 2008 and 2010 were compared.
RESULTS:
Microclimate conditions were also monitored in a control room with the same roof in both years. The average temperature in this room was lower in 2010, and it was decided to consider a time frame of 18 summer days with the same mean temperature in both years. In the rooms with three walls, the statistical analysis revealed that the diurnal maximum temperature decreased about 3.5 ºC due to the roof change, and the minimum temperature increased 0.5 ºC. As a result, the daily thermohygrometric variations resulted less pronounced in 2010, with a reduction of approximately 4 ºC, which is favorable for the preservation of mural paintings. In the room with four walls, the daily fluctuations also decreased about 4 ºC. Based on the results, other alternative actions are discussed aimed at improving the conservation conditions of wall paintings.
CONCLUSIONS:
The roof change has reduced the most unfavorable thermohygrometric conditions affecting the mural paintings, but additional actions should be adopted for a long term preservation of Pompeian frescoes.This work was partially supported by the Spanish Government (Ministerio de Ciencia e Innovacion) under projects HAR2010-21944-C02-01 and HAR2010-21944-C02-02.Merello Giménez, P.; García Diego, FJ.; Zarzo Castelló, M. (2013). Evaluation of corrective measures implemented for the preventive conservation of fresco paintings in Ariadne s house (Pompeii, Italy). Chemistry Central Journal. 7(1):87-87. doi:10.1186/1752-153X-7-87S878771DELOSRIOS, A., CAMARA, B., GARCIADELCURA, M., RICO, V., GALVAN, V., & ASCASO, C. (2009). Deteriorating effects of lichen and microbial colonization of carbonate building rocks in the Romanesque churches of Segovia (Spain). Science of The Total Environment, 407(3), 1123-1134. doi:10.1016/j.scitotenv.2008.09.042Nava, S., Becherini, F., Bernardi, A., Bonazza, A., Chiari, M., García-Orellana, I., … Vecchi, R. (2010). An integrated approach to assess air pollution threats to cultural heritage in a semi-confined environment: The case study of Michelozzo’s Courtyard in Florence (Italy). Science of The Total Environment, 408(6), 1403-1413. doi:10.1016/j.scitotenv.2009.07.03
NGTS-13b: A hot 4.8 Jupiter-mass planet transiting a subgiant star
We report the discovery of the massive hot Jupiter NGTS-13b by the Next
Generation Transit Survey (NGTS). The V = 12.7 host star is likely in the
subgiant evolutionary phase with log g = 4.04 0.05, T =
5819 73 K, M = 1.30 M, and R =
1.79 0.06 R. NGTS detected a transiting planet with a period of
P = 4.12 days around the star, which was later validated with the Transiting
Exoplanet Survey Satellite (TESS; TIC 454069765). We confirm the planet using
radial velocities from the CORALIE spectrograph. Using NGTS and TESS full-frame
image photometry combined with CORALIE radial velocities we determine NGTS-13b
to have a radius of R = 1.142 0.046 R, mass of M =
4.84 0.44 M and eccentricity e = 0.086 0.034. Some previous
studies suggest that 4 M may be a border between two separate
formation scenarios (e.g., core accretion and disk instability) and that
massive giant planets share similar formation mechanisms as lower-mass brown
dwarfs. NGTS-13b is just above 4 M making it an important addition to
the statistical sample needed to understand the differences between various
classes of substellar companions. The high metallicity, [Fe/H] = 0.25
0.17, of NGTS-13 does not support previous suggestions that massive giants are
found preferentially around lower metallicity host stars, but NGTS-13b does
support findings that more massive and evolved hosts may have a higher
occurrence of close-in massive planets than lower-mass unevolved stars
NGTS discovery of a highly inflated Saturn-mass planet and a highly irradiated hot Jupiter: NGTS-26 b and NGTS-27 b
We report the discovery of two new transiting giant exoplanets NGTS-26 b and NGTS-27 b by the Next Generation Transit Survey (NGTS). NGTS-26 b orbits around a G6-type main sequence star every 4.52 days. It has a mass of 0.29-0.06+0.07 MJup and a radius of 1.33-0.05+0.06 RJup making it a Saturn-mass planet with a highly inflated radius. NGTS-27 b orbits around a slightly evolved G3-type star every 3.37 days. It has a mass of 0.59-0.07+0.10 MJup and a radius of 1.40±0.04 RJup, making it a relatively standard hot Jupiter. The transits of these two planetary systems were re-observed and confirmed in photometry by the SAAO 1.0-m telescope, 1.2-m Euler Swiss telescope as well as the TESS spacecraft, and their masses were derived spectroscopically by the CORALIE, FEROS and HARPS spectrographs. Both giant exoplanets are highly irradiated by their host stars and present an anomalously inflated radius, especially NGTS-26 b which is one of the largest objects among peers of similar mass
Television viewing, food preferences, and food habits among children: A prospective epidemiological study
<p>Abstract</p> <p>Background</p> <p>Obesity has increased since the early 1980s, and despite numerous attempts, effective strategies to counter this worldwide epidemic are lacking. Food preferences are established early in life and are difficult to change later. There is therefore a need to identify factors that influence the development of food preferences. Our aim was therefore, to investigate cross-sectional and prospective associations between TV viewing habits and food preferences and habits, respectively. We hypothesized that more TV viewing was associated with less healthy concomitant and future food preferences and food habits.</p> <p>Methods</p> <p>Data are from the Danish part of European Youth Heart Study (EYHS) I and II, a prospective cohort study conducted among 8-10-year-old and 14-16-year-old Danes in 1997-98. Six years later 2003-04 the 8-10-year-olds were followed up at age 14-16 years, and a new group of 8-10-year olds were included. Data were analysed using mixed linear regression analysis. Cross-sectional analyses included 697 8-10-year-olds and 495 14-16-year-olds. Prospective analyses included 232 pupils with complete data at baseline and follow-up. Associations between TV viewing habits and the sum of healthy food preferences (ΣHFP), and the sum of healthy food habits (ΣHFH), respectively, were examined.</p> <p>Results</p> <p>Inverse cross-sectional associations between TV viewing (h/day) and both ΣHFP and ΣHFH were present for both the 8-10-year-old and the 14-16-year-old boys and girls. The frequency of meals in front of the TV (times/week) was also inversely associated with ΣHFP among 8-10-year-old boys, and with ΣHFH in all sex- and age groups. Among girls, baseline TV viewing (h/day) was directly associated with adverse development in the ΣHFP during follow-up. The concomitant 6-year changes in ΣHFH and TV viewing (h/day) were inversely associated in boys.</p> <p>Conclusions</p> <p>Long time spent on TV viewing, and possibly to a lesser degree, frequent consumption of meals during TV viewing, seem to be associated with generally having unhealthy food preferences and food habits among school-aged children. These associations, however, were not generally persistent after 6 years of follow-up.</p
- …