8,416 research outputs found
Impact of Daily Arctic Sea Ice Variability in CAM3.0 during Fall and Winter
Climate projections suggest that an ice-free summer Arctic Ocean is possible within several decades and with this comes the prospect of increased ship traffic and safety concerns. The daily sea ice concentration tendency in five Coupled Model Intercomparison Project phase 5 (CMIP5) simulations is compared with observations to reveal that many models underestimate this quantity that describes high-frequency ice movements, particularly in the marginal ice zone. To investigate whether high-frequency ice variability impacts the atmosphere, the Community Atmosphere Model, version 3.0 (CAM3.0), is forced by sea ice with and without daily fluctuations. Two 100-member ensemble experiments with daily varying (DAILY) and smoothly varying (SMTH) sea ice are conducted, along with a climatological control, for an anoma- lously low ice period (August 2006âNovember 2007). Results are presented for three periods: September 2006, October 2006, and DecemberâFebruary (DJF) 2006/07. The atmospheric response differs between DAILY and SMTH. In September, sea ice differences lead to an anomalous high and weaker storm activity over northern Europe. During October, the ice expands equatorward faster in DAILY than SMTH in the Siberian seas and leads to a local response of near-surface cooling. In DJF, there is a 1.5-hPa positive sea level pressure anomaly over North America, leading to anomalous northerly flow and anomalously cool continental U.S. temperatures. While the atmospheric responses are modest, the differences arising from high temporal frequency ice variability cannot be ignored. Increasing the accuracy of coupled model sea ice variations on short time scales is needed to improve short-term coupled model forecasts
âTears in My Eyes âCause Somebody Finally Understoodâ: Client Perceptions of Practitioners Following Brain Injury
Objective: The purpose of this study was to identify practitioner qualities and traits that clients with brain injury see as important. Method: An opportunistic sample of 51 participants with brain injury was interviewed about perceptions of service access and effectiveness. An interview guide was used to gather data for this phenomenological qualitative study. Four interviewers individually conducted audiotaped interviews, which were then transcribed. Coding and theme development were completed using HyperRESEARCHâą software. Results: Three themes regarding practitioner qualities emerged from the data: (a) roles of the provider, (b) perceived helpfulness of services, and (c) personal characteristics of the providers. Beneficial provider roles included advocate, friend, mentor, and team member. Perceptions of helpfulness of the services included relevance, meaningfulness, practical application, skill development potential, and whether periodic feedback on progress was provided. Personal characteristics of the provider valued by the participants were clear and honest communicator, supportive, respectful, good listener, and understanding. Conclusions: Practitioners need to pay increased attention to the perceptions of care and services of clients with brain injury. The current study closely supports previous research related to quality of care in the medical and community arenas and offers some additional suggestions to professionals who work with persons with brain injury, including learning how to time giving information to clients and how to understand client concerns without being prescriptive. Future research in this area needs to focus on and describe providers who demonstrate an abilityâthrough their willingness to don a variety of roles, their helpful services, and their personal characteristicsâto meet the unique needs of clients with brain injury
Color television study Final report, Nov. 1965 - Mar. 1966
Color television camera for transmission from lunar and earth orbits and lunar surfac
Lesbian and bisexual women's experiences of sexuality-based discrimination and their appearance concerns
Lesbian and bisexual women frequently experience sexuality-based discrimination, which is often based on others' judgements about their appearance. This short article aims to explore whether there is a relationship between lesbian and bisexual women's experiences of sexuality-based discrimination and their satisfaction with the way that they look. Findings from an online survey suggest that discrimination is negatively related to appearance satisfaction for lesbian women, but not for bisexual women. It is argued that this difference exists because lesbian appearance norms are more recognisable and distinctive than bisexual women's appearance norms
Improving Outcomes from Breast Cancer in a Low-Income Country: Lessons from Bangladesh
Women in low- and middle-income countries (LMICs) have yet to benefit from recent advances in breast cancer diagnosis and treatment now experienced in high-income countries. Their unique sociocultural and health system circumstances warrant a different approach to breast cancer management than that applied to women in high-income countries. Here, we present experience from the last five years working in rural Bangladesh. Case and consecutive series data, focus group and individual interviews, and clinical care experience provide the basis for this paper. These data illustrate a complex web of sociocultural, economic, and health system conditions which affect womens' choices to seek and accept care and successful treatment. We conclude that health system, human rights, and governance issues underlie high mortality from this relatively rare disease in Bangladesh
Matrix-free calcium in isolated chromaffin vesicles
Isolated secretory vesicles from bovine adrenal medulla contain 80 nmol of Ca2+ and 25 nmol
of Mg2+ per milligram of protein. As determined with a Ca2+-selective electrode, a further accumulation
of about 160 nmol of Ca2+/mg of protein can be attained upon addition of the Ca2+ ionophore A23187.
During this process protons are released from the vesicles, in exchange for Ca2+ ions, as indicated by the
decrease of the pH in the incubation medium or the release of 9-aminoacridine previously taken up by the
vesicles. Intravesicular Mg2+ is not released from the vesicles by A23 187, as determined by atomic emission
spectroscopy. In the presence of N H Q , which causes the collapse of the secretory vesicle transmembrane
proton gradient (ApH), Ca2+ uptake decreases. Under these conditions A23 187-mediated influx of Ca2+
and efflux of H+ cease at Ca2+ concentrations of about 4 pM. Below this concentration Ca2+ is even released
from the vesicles. At the Ca2+ concentration at which no net flux of ions occurs the intravesicular matrix
free Ca2+ equals the extravesicular free Ca2+. In the absence of NH4C1 we determined an intravesicular
pH of 6.2. Under these conditions the Ca2+ influx ceases around 0.15 pM. From this value and the known
pH across the vesicular membrane an intravesicular matrix free Ca2+ concentration of about 24 pM was
calculated. This is within the same order of magnitude as the concentration of free Ca2+ in the vesicles
determined in the presence of NH4C1. Calculation of the total Ca2+ present in the secretory vesicles gives
an apparent intravesicular Ca2+ concentration of 40 mM, which is a factor of lo4 higher than the free
intravesicular concentration of Ca2+. It can be concluded, therefore, that the concentration gradient of free
Ca2+ across the secretory vesicle membrane in the intact chromaffin cells is probably small, which implies
that less energy is required to accumulate and maintain Ca2+ within the vesicles than was previously
anticipated
R-Estimates vs. GMM: A Theoretical Case Study of Validity and Efficiency
What role should assumptions play in inference? We present a small theoretical case study of a simple, clean case, namely the nonparametric comparison of two continuous distributions using (essentially) information about quartiles, that is, the central information displayed in a pair of boxplots. In particular, we contrast a suggestion of John Tukeyâthat the validity of inferences should not depend on assumptions, but assumptions have a role in efficiencyâwith a competing suggestion that is an aspect of Hansenâs generalized method of momentsâthat methods should achieve maximum asymptotic efficiency with fewer assumptions. In our case study, the practical performance of these two suggestions is strikingly different. An aspect of this comparison concerns the unification or separation of the tasks of estimation assuming a model and testing the fit of that model. We also look at a method (MERT) that aims not at best performance, but rather at achieving reasonable performance across a set of plausible models
Selection of a New Highly Resistant Strain for Malolactic Fermentation under Difficult Conditions
Malolactic fermentation (MLF) is a biological process that contributes to wine quality, but it is frequently affectedby various vinification conditions. Resistance to four wine-limiting factors was studied with respect to 10 Oenococcusoeni strains in order to select a suitable strain for performing reliable MLF in difficult wines. Resistance to lowfermentation temperature, high SO2 and/or ethanol concentration, and low pH were assayed in laboratory tests. Apool of the most resistant strains was used in a set of laboratory MLFs. At the end of fermentation, the dominantstrains were identified by RAPD-PCR. The PN4 strain was found to be dominant in the majority of cases and underthe most detrimental wine conditions, and it was therefore chosen as the single-strain inoculum for the subsequentMLF trials. The effectiveness of the PN4 strain was confirmed in a series of MLFs carried out in three differentcountries under experimental and industrial conditions. It accomplished MLF in wines with up to 15.8% ethanol,pH as low as 3.0, 60 mg/L of free SO2, and in fermentation temperatures below 17ÂșC. Our findings indicate that theO. oeni PN4 strain could be an effective starter, guaranteeing regular and reliable MLF fermentation
Data collection in protein crystallography: capillary effects and background corrections
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