803 research outputs found
Feshbach molecule formation in a Bose-Fermi mixture
We investigate magnetoassociation of ultracold fermionic Feshbach molecules
in a mixture of K and Rb atoms, where we can create as many as
KRb molecules with a conversion efficiency as high
as 45%. In the perturbative regime, we find that the conversion efficiency
depends linearly on the density overlap of the two gases, with a slope that
matches a parameter-free model that uses only the atom masses and the known
Feshbach resonance parameters. In the saturated regime, we find that the
maximum number of Feshbach molecules depends on the atoms' phase-space density.
At higher temperatures, our measurements agree with a phenomenological model
that successfully describes the formation of bosonic molecules from either Bose
or Fermi gases. However, for quantum degenerate atom gas mixtures, we measure
significantly fewer molecules than this model predicts.Comment: 6 pages, 6 figure
Role of arginase 2 in systemic metabolic activity and adipose tissue fatty acid metabolism in diet-induced obese mice
Visceral adipose tissue (VAT) inflammation and metabolic dysregulation are key components of obesity-induced metabolic disease. Upregulated arginase, a ureahydrolase enzyme with two isoforms (A1-cytosolic and A2-mitochondrial), is implicated in pathologies associated with obesity and diabetes. This study examined A2 involvement in obesity-associated metabolic and vascular disorders. WT and globally deleted A2(−/−) or A1(+/−) mice were fed either a high fat/high sucrose (HFHS) diet or normal diet (ND) for 16 weeks. Increases in body and VAT weight of HFHS-fed WT mice were abrogated in A2−/−, but not A1+/−, mice. Additionally, A2−/− HFHS-fed mice exhibited higher energy expenditure, lower blood glucose, and insulin levels compared to WT HFHS mice. VAT and adipocytes from WT HFHS fed mice showed greater A2 expression and adipocyte size and reduced expression of PGC-1α, PPAR-γ, and adiponectin. A2 deletion blunted these effects, increased levels of active AMPK-α, and upregulated genes involved in fatty acid metabolism. A2 deletion prevented HFHS-induced VAT collagen deposition and inflammation, which are involved in adipocyte metabolic dysfunction. Endothelium-dependent vasorelaxation, impaired by HFHS diet, was significantly preserved in A2−/− mice, but more prominently maintained in A1+/− mice. In summary, A2 is critically involved in HFHS-induced VAT inflammation and metabolic dysfunction
Soil methane sink capacity response to a long-term wildfire chronosequence in Northern Sweden
Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished
'Sifting the significance from the data' - the impact of high-throughput genomic technologies on human genetics and health care.
This report is of a round-table discussion held in Cardiff in September 2009 for Cesagen, a research centre within the Genomics Network of the UK's Economic and Social Research Council. The meeting was arranged to explore ideas as to the likely future course of human genomics. The achievements of genomics research were reviewed, and the likely constraints on the pace of future progress were explored. New knowledge is transforming biology and our understanding of evolution and human disease. The difficulties we face now concern the interpretation rather than the generation of new sequence data. Our understanding of gene-environment interaction is held back by our current primitive tools for measuring environmental factors, and in addition, there may be fundamental constraints on what can be known about these complex interactions.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Examining the efficacy of a digital version of the Self-Administered Interview
Objectives. The Self-Administered Interview (SAI©) is an investigative tool designed to facilitate the reporting of comprehensive initial statements by witnesses. Given increasing use of technology to communicate, many witnesses may prefer to provide investigators with accounts of what they have seen using online or mobile reporting platforms. Research shows that the SAI© elicits more accurate information from witnesses than other reporting formats. To date, however, the SAI© has only been tested in a paper-based format. The aim of the current research was to examine whether the benefits of the SAI© for witness reporting extend to digital reporting formats.
Method: In two experiments, we examined whether completing the SAI© on a computer or mobile device (as opposed to using a paper-based format) had any effect on the quantity or quality of information reported by mock witnesses. We also assessed whether the format of the initial report had any impact on performance in a delayed recall test.
Hypotheses. Based on available research on use of technology, we expected that witness accounts would be shorter when provided via mobile devices than via other formats. Drawing on past research outlined in the Introduction, we predicted that less detailed initial accounts would affect the quality of subsequent accounts.
Results. We found no differences between computer, mobile, or paper-based formats with respect to the quantity or quality of information reported in the SAI© or content of follow-up reports collected oneweek later.
Conclusion. The findings suggest that administering the SAI© in online or mobile formats is unlikely to be detrimental to witness reporting. Given the time and resource costs associated with paper forms, as well as the additional functionality that digital presentation may afford, a digital SAI© may prove to be a useful investigative tool
Silent Sinus Syndrome: An Uncommon Cause of Diplopia
Background: Silent sinus syndrome is a rare condition with multiple ophthalmic findings of significance. Chronic, subclinical maxillary sinus inflammation alters the pressure gradient, leading to eventual maxillary sinus collapse, orbital floor depression, enophthalmos, and diplopia.
Case Report: Functional endoscopic sinus surgery may be indicated to correct diplopia and/or cosmesis.
Conclusion: Patients unbothered by facial asymmetry may be managed with prism in eyeglasses
Tests of universal three-body physics in an ultracold Bose-Fermi mixture
Recent measurements of Efimov resonances in a number of ultracold atom
species have revealed an unexpected universality, in which three-body
scattering properties are determined by the van der Waals length of the
two-body interaction potential. To investigate whether this universality
extends to heteronuclear mixtures, we measure loss rate coefficients in an
ultracold trapped gas of K and Rb atoms. We find an Efimov-like
resonance in the rate of inelastic collisions between KRb
Feshbach molecules and Rb atoms. However, we do not observe any
Efimov-related resonances in the rates of inelastic collisions between three
atoms. These observations are compared to previous measurements by the LENS
group of Efimov resonances in a K and Rb mixture as well as to
recent predictions.Comment: 5 pages, 3 figure
Establishing a Community of Practice for Doctoral Studies Amidst the COVID-19 Pandemic
In this discussion paper, we describe our experience completing the first year of the doctorate in nursing program at a large urban academic centre during the COVID-19 pandemic. We highlight the current nursing shortage and the importance of supporting all nursing students, including nurses in doctoral programs, towards successful graduation. We describe the development of a virtual community of practice incorporating five key strategies: Building community, fostering collaboration, strengthening connection, enhancing creativity, and promoting consistency. We believe that utilizing these strategies will contribute to our success and may be relevant to nursing leaders seeking to support the development of more doctorally prepared nurses. Participation in a community of practice early on in doctoral education will not only better prepare students for success in their program, but also continued success as they progress through their careers. It is important for students to not only make connections with peers in their area of academic study, but to also reach out to peers in other disciplines to improve both individual and interdisciplinary growth. Program administrators and educators can encourage the formation of community of practice among novice doctoral students. This encouragement can be achieved using a virtual platform, or in-person networking opportunities. Inviting incoming graduate students to connect with each other and with students from previous cohorts also fosters community of practice formation.
Résumé
Dans ce texte de discussion, nous décrivons notre expérience relative à la première année du doctorat en sciences infirmières dans un grand centre universitaire urbain pendant la pandémie de COVID-19. Nous soulignons la pénurie actuelle d’infirmières et l’importance de soutenir toutes les étudiantes en sciences infirmières, y compris les infirmières inscrites à un programme de doctorat, vers la réussite de leurs études. Nous décrivons le développement d’une communauté virtuelle de pratique intégrant cinq stratégies clés : créer une communauté, favoriser la collaboration, renforcer les liens, mettre en valeur la créativité et promouvoir la cohérence. Nous pensons que l’utilisation de ces stratégies contribuera à notre succès et pourrait être pertinente pour les infirmières chefs de file qui cherchent à soutenir le développement d’un plus grand nombre d’infirmières préparées au doctorat. La participation à une communauté de pratique dès le début de la formation doctorale permettra non seulement de mieux préparer les étudiantes à réussir dans leur programme, mais favorisera également leur poursuite d’une carrière fructueuse. Il est important pour les étudiantes d’établir des liens non seulement avec des pairs dans leur domaine d’études universitaires, mais qu’ils entrent également en contact avec des pairs d’autres disciplines pour améliorer à la fois leur croissance individuelle et interdisciplinaire. Les administratrices de programme et les enseignantes peuvent encourager la formation d’une communauté de pratique parmi les doctorantes novices. Cet encouragement peut être réalisé à l’aide d’une plateforme virtuelle ou d’occasions de réseautage en personne. Inviter les étudiantes diplômées à entrer en contact les unes avec les autres et avec les étudiantes des cohortes précédentes favorise également la formation d’une communauté de pratique
Optical types of inland and coastal waters
Inland and coastal waterbodies are critical components of the global biosphere. Timely monitoring is necessary to enhance our understanding of their functions, the drivers impacting on these functions and to deliver more effective management. The ability to observe waterbodies from space has led to Earth observation (EO) becoming established as an important source of information on water quality and ecosystem condition. However, progress toward a globally valid EO approach is still largely hampered by inconsistences over temporally and spatially variable in‐water optical conditions. In this study, a comprehensive dataset from more than 250 aquatic systems, representing a wide range of conditions, was analyzed in order to develop a typology of optical water types (OWTs) for inland and coastal waters. We introduce a novel approach for clustering in situ hyperspectral water reflectance measurements (n = 4045) from multiple sources based on a functional data analysis. The resulting classification algorithm identified 13 spectrally distinct clusters of measurements in inland waters, and a further nine clusters from the marine environment. The distinction and characterization of OWTs was supported by the availability of a wide range of coincident data on biogeochemical and inherent optical properties from inland waters. Phylogenetic trees based on the shapes of cluster means were constructed to identify similarities among the derived clusters with respect to spectral diversity. This typification provides a valuable framework for a globally applicable EO scheme and the design of future EO missions
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