179 research outputs found
Chemical telemetry of OH observed to measure interstellar magnetic fields
We present models for the chemistry in gas moving towards the ionization
front of an HII region. When it is far from the ionization front, the gas is
highly depleted of elements more massive than helium. However, as it approaches
the ionization front, ices are destroyed and species formed on the grain
surfaces are injected into the gas phase. Photodissociation removes gas phase
molecular species as the gas flows towards the ionization front. We identify
models for which the OH column densities are comparable to those measured in
observations undertaken to study the magnetic fields in star forming regions
and give results for the column densities of other species that should be
abundant if the observed OH arises through a combination of the liberation of
H2O from surfaces and photodissociation. They include CH3OH, H2CO, and H2S.
Observations of these other species may help establish the nature of the OH
spatial distribution in the clouds, which is important for the interpretation
of the magnetic field results.Comment: 11 pages, 2 figures, accepted by Astrophysics and Space Scienc
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Development of a coal-fired gas turbine cogeneration system: Status report
The Allison Advanced Coal-Fueled Turbine Program is now in the sixth year of a development effort that has led to a POC engine demonstration test on a Coal-Water-Slurry (CWS) fuel. Earlier forecasts by CWS suppliers that suitable CWS fuels would be commercially available at an economic price have not been realized. A program replan has, therefore, been executed that incorporates the use of readily available dry pulverized coal. To support this program, technology issues relating to combustor performance and emission control, hot gas cleanup, and turbine deposition, erosion and corrosion (DEC) have been addressed. In addition, system assessment studies have been performed to evaluate the commercial prospects for small ( 100 MWe) utility-sized gas turbines. These results are reported by Wenglarz (1992). Combustor and engine tests on dry coal are now planned in preparation for a commercial demonstration that will follow the completion of this program
AMI observations of Lynds Dark Nebulae: further evidence for anomalous cm-wave emission
Observations at 14.2 to 17.9 GHz made with the AMI Small Array towards
fourteen Lynds Dark Nebulae with a resolution of 2' are reported. These sources
are selected from the SCUBA observations of Visser et al. (2001) as small
angular diameter clouds well matched to the synthesized beam of the AMI Small
Array. Comparison of the AMI observations with radio observations at lower
frequencies with matched uv-plane coverage is made, in order to search for any
anomalous excess emission which can be attributed to spinning dust. Possible
emission from spinning dust is identified as a source within a 2' radius of the
Scuba position of the Lynds dark nebula, exhibiting an excess with respect to
lower frequency radio emission. We find five sources which show a possible
spinning dust component in their spectra. These sources have rising spectral
indices in the frequency range 14.2--17.9 GHz. Of these five one has already
been reported, L1111, we report one new definite detection, L675, and three new
probable detections (L944, L1103 and L1246). The relative certainty of these
detections is assessed on the basis of three criteria: the extent of the
emission, the coincidence of the emission with the Scuba position and the
likelihood of alternative explanations for the excess. Extended microwave
emission makes the likelihood of the anomalous emission arising as a
consequence of a radio counterpart to a protostar or a proto-planetary disk
unlikely. We use a 2' radius in order to be consistent with the IRAS
identifications of dark nebulae (Parker 1988), and our third criterion is used
in the case of L1103 where a high flux density at 850 microns relative to the
FIR data suggests a more complicated emission spectrum.Comment: submitted MNRA
Investigating Protostellar Accretion-Driven Outflows Across the Mass Spectrum: JWST NIRSpec IFU 3-5~m Spectral Mapping of Five Young Protostars
Investigating Protostellar Accretion (IPA) is a Cycle 1 JWST program using
the NIRSpec+MIRI IFUs to obtain 2.9--28 m spectral cubes of five young
protostars with luminosities of 0.2 to 10,000 L in their primary
accretion phase. This paper introduces the NIRSpec 2.9--5.3 m data of the
inner 840-9000 au with spatial resolutions from 28-300 au. The spectra show
rising continuum emission, deep ice absorption, emission from H, H~I, and
[Fe~II], and the CO fundamental series in emission and absorption. Maps of the
continuum emission show scattered light cavities for all five protostars. In
the cavities, collimated jets are detected in [Fe~II] for the four ~L protostars, two of which are additionally traced in
Br-. Knots of [Fe~II] emission are detected toward the most luminous
protostar, and knots of [FeII] emission with dynamical times of ~yrs are
found in the jets of the others. While only one jet is traced in H, knots
of H and CO are detected in the jets of four protostars. H is seen
extending through the cavities showing they are filled by warm molecular gas.
Bright H emission is seen along the walls of a single cavity, while in
three cavities, narrow shells of H emission are found, one of which has an
[Fe~II] knot at its apex. These data show cavities containing collimated jets
traced in atomic/ionic gas surrounded by warm molecular gas in a wide-angle
wind and/or gas accelerated by bow shocks in the jets.Comment: 30 pages, 11 figure
Exploring the lived experience of gay men with prostate cancer: A phenomenological study
Purpose: Gay men with prostate cancer are an âinvisible speciesâ in the research literature despite concerns that the impact of treatment may be more profound and in some ways unique compared to heterosexual men. The aim of this research is to explore the lived experience of gay men with prostate cancer. Method: In-depth interviews were recorded and transcribed verbatim from a purposive sample of eight gay men treated for prostate cancer in Ireland. A qualitative methodological approach employing Giorgi's descriptive phenomenological method was used to collect and analyse data. Findings: Three key aspects emerged representing the essence of the participants lived experience; The experience of diagnosis, treatment decision making, and the impact of treatment, with sub-themes of shock of diagnosis, the generalist nature of information, sexual side effects and incontinence, and masculinity and gay identity. Secondly, the experience of the healthcare service with sub-themes of sexual orientation disclosure and communication with the healthcare team; and thirdly, sources of support and means of coping which included significant others, family & friends, cancer support groups, and gay resources and support services. Conclusion: Gay men with prostate cancer have unmet information and supportive care needs throughout their prostate cancer journey, especially related to the impact of sexual dysfunction and associated rehabilitation, negatively impacting their quality of life. Issues associated with heteronormativity, minority stress, and stigma may influence how gay men interact with the health service, or how they perceive the delivery of care. Healthcare education providers should update prostate cancer education programmes accordingly
The genomes of two key bumblebee species with primitive eusocial organization
Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation
A systematic review of dietary, nutritional, and physical activity interventions for the prevention of prostate cancer progression and mortality
PURPOSE: Given the long-term, although potentially fatal, nature of prostate cancer, there is increasing observational evidence for the reduction in disease progression and mortality through changes in lifestyle factors. METHODS: We systematically reviewed dietary, nutritional, and physical activity randomized interventions aimed at modifying prostate cancer progression and disease-specific mortality, including a detailed assessment of risk of bias and methodological quality. RESULTS: Forty-four randomized controlled trials of lifestyle interventions, with prostate cancer progression or mortality outcomes, were identified. Substantial heterogeneity of the data prevented a meta-analysis. The included trials involved 3,418 prostate cancer patients, median 64 men per trial, from 13 countries. A trial of a nutritional supplement of pomegranate seed, green tea, broccoli, and turmeric; a trial comparing flaxseed, low-fat diet, flaxseed, and low-fat diet versus usual diet; and a trial supplementing soy, lycopene, selenium, and coenzyme Q10, all demonstrated beneficial effects. These trials were also assessed as having low risk of bias and high methodological quality (as were seven other trials with no evidence of benefit). The remaining trials were either underpowered, at high or unclear risk of bias, inadequately reported, of short duration or measured surrogate outcomes of unproven relationship to mortality or disease progression, which precluded any benefits reported being reliable. CONCLUSION: Large, well-designed randomized trials with clinical endpoints are recommended for lifestyle modification interventions. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10552-015-0659-4) contains supplementary material, which is available to authorized users
Understanding tumor heterogeneity as functional compartments - superorganisms revisited
Compelling evidence broadens our understanding of tumors as highly heterogeneous populations derived from one common progenitor. In this review we portray various stages of tumorigenesis, tumor progression, self-seeding and metastasis in analogy to the superorganisms of insect societies to exemplify the highly complex architecture of a neoplasm as a system of functional "castes.
Co-founding ant queens prevent disease by performing prophylactic undertaking behaviour
Abstract Background Social insects form densely crowded societies in environments with high pathogen loads, but have evolved collective defences that mitigate the impact of disease. However, colony-founding queens lack this protection and suffer high rates of mortality. The impact of pathogens may be exacerbated in species where queens found colonies together, as healthy individuals may contract pathogens from infectious co-founders. Therefore, we tested whether ant queens avoid founding colonies with pathogen-exposed conspecifics and how they might limit disease transmission from infectious individuals. Results Using Lasius niger queens and a naturally infecting fungal pathogen Metarhizium brunneum, we observed that queens were equally likely to found colonies with another pathogen-exposed or sham-treated queen. However, when one queen died, the surviving individual performed biting, burial and removal of the corpse. These undertaking behaviours were performed prophylactically, i.e. targeted equally towards non-infected and infected corpses, as well as carried out before infected corpses became infectious. Biting and burial reduced the risk of the queens contracting and dying from disease from an infectious corpse of a dead co-foundress. Conclusions We show that co-founding ant queens express undertaking behaviours that, in mature colonies, are performed exclusively by workers. Such infection avoidance behaviours act before the queens can contract the disease and will therefore improve the overall chance of colony founding success in ant queens
Do genetic factors protect for early onset lung cancer? A case control study before the age of 50 years
<p>Abstract</p> <p>Background</p> <p>Early onset lung cancer shows some familial aggregation, pointing to a genetic predisposition. This study was set up to investigate the role of candidate genes in the susceptibility to lung cancer patients younger than 51 years at diagnosis.</p> <p>Methods</p> <p>246 patients with a primary, histologically or cytologically confirmed neoplasm, recruited from 2000 to 2003 in major lung clinics across Germany, were matched to 223 unrelated healthy controls. 11 single nucleotide polymorphisms of genes with reported associations to lung cancer have been genotyped.</p> <p>Results</p> <p>Genetic associations or gene-smoking interactions was found for <it>GPX1(Pro200Leu) </it>and <it>EPHX1(His113Tyr)</it>. Carriers of the Leu-allele of <it>GPX1(Pro200Leu) </it>showed a significant risk reduction of OR = 0.6 (95% CI: 0.4â0.8, p = 0.002) in general and of OR = 0.3 (95% CI:0.1â0.8, p = 0.012) within heavy smokers. We could also find a risk decreasing genetic effect for His-carriers of <it>EPHX1(His113Tyr) </it>for moderate smokers (OR = 0.2, 95% CI:0.1â0.7, p = 0.012). Considered both variants together, a monotone decrease of the OR was found for smokers (OR of 0.20; 95% CI: 0.07â0.60) for each protective allele.</p> <p>Conclusion</p> <p>Smoking is the most important risk factor for young lung cancer patients. However, this study provides some support for the T-Allel of <it>GPX1(Pro200Leu) </it>and the C-Allele of <it>EPHX1(His113Tyr) </it>to play a protective role in early onset lung cancer susceptibility.</p
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