214 research outputs found
Scintillation and charge extraction from the tracks of energetic electrons in superfluid helium-4
An energetic electron passing through liquid helium causes ionization along
its track. The ionized electrons quickly recombine with the resulting positive
ions, which leads to the production of prompt scintillation light. By applying
appropriate electric fields, some of the ionized electrons can be separated
from their parent ions. The fraction of the ionized electrons extracted in a
given applied field depends on the separation distance between the electrons
and the ions. We report the determination of the mean electron-ion separation
distance for charge pairs produced along the tracks of beta particles in
superfluid helium at 1.5 K by studying the quenching of the scintillation light
under applied electric fields. Knowledge of this mean separation parameter will
aid in the design of particle detectors that use superfluid helium as a target
material.Comment: 10 pages, 8 figure
Spectral Energy Distributions of Local Luminous And Ultraluminous Infrared Galaxies
Luminous and ultraluminous infrared galaxies ((U)LIRGs) are the most extreme
star forming galaxies in the universe. The local (U)LIRGs provide a unique
opportunity to study their multi-wavelength properties in detail for comparison
to their more numerous counterparts at high redshifts. We present common large
aperture photometry at radio through X-ray wavelengths, and spectral energy
distributions (SEDs) for a sample of 53 nearby LIRGs and 11 ULIRGs spanning log
(LIR/Lsun) = 11.14-12.57 from the flux-limited Great Observatories All-sky LIRG
Survey (GOALS). The SEDs for all objects are similar in that they show a broad,
thermal stellar peak and a dominant FIR thermal dust peak, where nuLnu(60um) /
nuLnu(V) increases from ~2-30 with increasing LIR. When normalized at
IRAS-60um, the largest range in the luminosity ratio,
R(lambda)=log[nuLnu(lambda)/nuLnu(60um)] observed over the full sample is seen
in the Hard X-rays (HX=2-10 keV). A small range is found in the Radio (1.4GHz),
where the mean ratio is largest. Total infrared luminosities, LIR(8-1000um),
dust temperatures, and dust masses were computed from fitting thermal dust
emission modified blackbodies to the mid-infrared (MIR) through submillimeter
SEDs. The new results reflect an overall ~0.02 dex lower luminosity than the
original IRAS values. Total stellar masses were computed by fitting stellar
population synthesis models to the observed near-infrared (NIR) through
ultraviolet (UV) SEDs. Mean stellar masses are found to be log(M/Msun) =
10.79+/-0.40. Star formation rates have been determined from the infrared
(SFR_IR~45Msun/yr) and from the monochromatic UV luminosities
(SFR_UV~1.3Msun/yr), respectively. Multiwavelength AGN indicators have be used
to select putative AGN: about 60% of the ULIRGs would have been classified as
an AGN by at least one of the selection criteria.Comment: 39 pages, including 12 figures and 11 tables; accepted for
publication in ApJ
From Select Agent to an Established Pathogen: The Response to \u3ci\u3ePhakopsora pachyrhizi\u3c/i\u3e (Soybean Rust) in North America
The pathogen causing soybean rust, Phakopsora pachyrhizi, was first described in Japan in 1902. The disease was important in the Eastern Hemisphere for many decades before the fungus was reported in Hawaii in 1994, which was followed by reports from countries in Africa and South America. In 2004, P. pachyrhizi was confirmed in Louisiana, making it the first report in the continental United States. Based on yield losses from countries in Asia, Africa, and South America, it was clear that this pathogen could have a major economic impact on the yield of 30 million ha of soybean in the United States. The response by agencies within the United States Department of Agriculture, industry, soybean check-off boards, and universities was immediate and complex. The impacts of some of these activities are detailed in this review. The net result has been that the once dreaded disease, which caused substantial losses in other parts of the world, is now better understood and effectively managed in the United States. The disease continues to be monitored yearly for changes in spatial and temporal distribution so that soybean growers can continue to benefit by knowing where soybean rust is occurring during the growing season
Process evaluation of appreciative inquiry to translate pain management evidence into pediatric nursing practice
Background
Appreciative inquiry (AI) is an innovative knowledge translation (KT) intervention that is compatible with the Promoting Action on Research in Health Services (PARiHS) framework. This study explored the innovative use of AI as a theoretically based KT intervention applied to a clinical issue in an inpatient pediatric care setting. The implementation of AI was explored in terms of its acceptability, fidelity, and feasibility as a KT intervention in pain management.
Methods
A mixed-methods case study design was used. The case was a surgical unit in a pediatric academic-affiliated hospital. The sample consisted of nurses in leadership positions and staff nurses interested in the study. Data on the AI intervention implementation were collected by digitally recording the AI sessions, maintaining logs, and conducting individual semistructured interviews. Data were analysed using qualitative and quantitative content analyses and descriptive statistics. Findings were triangulated in the discussion.
Results
Three nurse leaders and nine staff members participated in the study. Participants were generally satisfied with the intervention, which consisted of four 3-hour, interactive AI sessions delivered over two weeks to promote change based on positive examples of pain management in the unit and staff implementation of an action plan. The AI sessions were delivered with high fidelity and 11 of 12 participants attended all four sessions, where they developed an action plan to enhance evidence-based pain assessment documentation. Participants labeled AI a 'refreshing approach to change' because it was positive, democratic, and built on existing practices. Several barriers affected their implementation of the action plan, including a context of change overload, logistics, busyness, and a lack of organised follow-up.
Conclusions
Results of this case study supported the acceptability, fidelity, and feasibility of AI as a KT intervention in pain management. The AI intervention requires minor refinements (e.g., incorporating continued follow-up meetings) to enhance its clinical utility and sustainability. The implementation process and effectiveness of the modified AI intervention require evaluation in a larger multisite study
Breast cancer susceptibility genes analysed into three groups Genomics and breast cancer: the different levels of inherited susceptibility
Site fidelity and movement patterns of short-finned pilot whales within the Canary Islands : evidence for resident and transient populations
Funding: co-funded by the Canary Government (ConsejerĂa de PolĂtica Territorial, Sostenibilidad y Seguridad), the Spanish Government (FundaciĂłn Biodiversidad and Ministerio de Medio Ambiente, Medio Rural y Marino), FundaciĂłn La Caixa, and by a number of international projects funded by EU programmes MACETUS (FEDER/INTERREG III-B MAC/4.2/M10), EMECETUS (FEDER/INTERREG III-B56105/MAC/4.2/M10), LIFE (LIFE03NAT0062), INDEMARES LIFE+ (LIFE07/NAT/E/00732).1. The geographic location and oceanographic, physical, and chemical water properties make the Canary Islands one of the planet's biodiversity hotspots. The shortâfinned pilot whale (Globicephala macrorhynchus) is one of the archipelago's most commonly encountered species and is potentially vulnerable to a range of anthropogenic pressures, including habitat degradation, acoustic pollution, fishing, whaleâwatching operations, and shipping. Assessment of impact has not been possible because of a lack of even basic information about occurrence and distribution. 2. Spatial and temporal distributions, ranging behaviour, and residence patterns of shortâfinned pilot whales were explored for the first time using survey and photoâidentification data collected in the Canary Islands between 1999 and 2012. In total, 1,081 pilot whale sightings were recorded during 70,620 km of search effort over 1,782 survey days. 3. Pilot whales were detected year round and distributed nonâuniformly within the archipelago, with greater densities concentrated in patchy areas mainly on the leeward side of the main islands. In total, 1,320 wellâmarked individuals were identified, which exhibited a large degree of variability in site fidelity. 4. Different but not isolated subpopulations of pilot whales that share ranges and maintain social interactions were apparently present in the Canary Islands. Strong evidence of an islandâassociated subpopulation was found, with a group of 50 âcore residentâ individuals associated particularly with Tenerife. There were also âtransientâ individuals or temporary migrants, which, probably driven by interâ and intraâspecific competition, may travel long distances whilst using the archipelago as part of a larger range. 5. These findings fill a major gap in the knowledge of this speciesâ occurrence, distribution, movements, and site fidelity in the archipelago and provide much needed data to allow the initiation of informed conservation assessments and management actions.PostprintPeer reviewe
Relational hopes: A study of the lived experience of hope in some patients hospitalized for intentional self-harm
Hopelessness is a well-established predictor of suicide, and inspiring hope is an important goal in mental health care, but there are few studies of hope among persons with suicidal behavior. The aim of this study was to interpret the lived experience of hope in some patients hospitalized for intentional self-harm. Twelve persons that had engaged in suicidal behavior by ingesting an overdose of medication were interviewed shortly after hospitalization and asked to narrate about their hopes. The transcripts were analyzed using a phenomenological hermeneutic method inspired by Ricoeur's theory of interpretation. The naĂŻve reading was one of hope being relational. The structural analysis identified three themes: hopes for life, hopes for death, and the act of hoping. We interpreted the common theme of the interviews as being definite and indefinite relational hopes for life and death. For clinicians, expressions of indefinite hopes may raise concerns about the low likelihood of fulfillment. However, the expression of indefinite hope may serve to avoid experiencing failure, disappointment, and hopelessness
Hope in actionâfacing cardiac death: A qualitative study of patients with life-threatening disease
Coping with existential challenges is important when struck by serious disease, but apart from cancer and palliative care little is known about how patients deal with such issues and maintain hope. To explore how patients with life-threatening heart disease experience hope when coping with mortality and other existential challenges, we conducted a qualitative study with semi-structured interviews. We made a purposive sample of 11 participants (26â88 years) who had experienced life-threatening disease: eight participants with serious heart disease, two with cancer, and one with severe chronic obstructive pulmonary disease. Analysis was by systematic text condensation. The findings showed that hope could enhance coping and diminish existential distress when patients were confronted with mortality and other existential challenges. Hope was observed as three types of dynamic work: to shift perception of mortality from overwhelming horror toward suppression or peaceful acceptance, to foster reconciliation instead of uncertainty when adapting to the new phase of life, and to establish go-ahead spirit instead of resignation as their identity. Meaning of life could, hence, be sustained in spite of serious threats to the persons' future, everyday life, and self-conception. The work of hoping could be supported or disturbed by relationships with family, friends, and health care professionals. Hope can be regarded as an active, dynamic state of existential coping among patients with life-threatening disease. Physicians may support this coping and thereby provide personal growth and alleviation of existential distress by skillfully identifying, acknowledging, and participating in the work of hoping performed by the patient
Pacific Oceanâwide profile of CYP1A1 expression, stable carbon and nitrogen isotope ratios, and organic contaminant burden in sperm whale skin biopsies
This paper is not subject to U.S. copyright. The definitive version was published in Environmental Health Perspectives 119 (2011): 337-343, doi:10.1289/ehp.0901809.Background: Ocean pollution affects marine organisms and ecosystems as well as humans. The International Oceanographic Commission recommends ocean health monitoring programs to investigate the presence of marine contaminants and the health of threatened species and the use of multiple and early-warning biomarker approaches.
Objective: We explored the hypothesis that biomarker and contaminant analyses in skin biopsies of the threatened sperm whale (Physeter macrocephalus) could reveal geographical trends in exposure on an oceanwide scale.
Methods: We analyzed cytochrome P450 1A1 (CYP1A1) expression (by immunohistochemistry), stable nitrogen and carbon isotope ratios (as general indicators of trophic position and latitude, respectively), and contaminant burdens in skin biopsies to explore regional trends in the Pacific Ocean.
Results: Biomarker analyses revealed significant regional differences within the Pacific Ocean. CYP1A1 expression was highest in whales from the Galapagos, a United Nations Educational, Scientific, and Cultural Organization World Heritage marine reserve, and was lowest in the sampling sites farthest away from continents. We examined the possible influence of the whalesâ sex, diet, or range and other parameters on regional variation in CYP1A1 expression, but data were inconclusive. In general, CYP1A1 expression was not significantly correlated with contaminant burdens in blubber. However, small sample sizes precluded detailed chemical analyses, and power to detect significant associations was limited.
Conclusions: Our large-scale monitoring study was successful at identifying regional differences in CYP1A1 expression, providing a baseline for this known biomarker of exposure to aryl hydrocarbon receptor agonists. However, we could not identify factors that explained this variation. Future oceanwide CYP1A1 expression profiles in cetacean skin biopsies are warranted and could reveal whether globally distributed chemicals occur at biochemically relevant concentrations on a global basis, which may provide a measure of ocean integrity.Funding was provided by National Institute of Environmental Health Sciences grant P42-ES-0469, Superfund Basic Research Program grant P42ES007381, NOAA Sea Grant NA86RG0075 R/B-162, and the Ocean Alliance
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