3,763 research outputs found
Observing Molecular Spinning via the Rotational Doppler Effect
When circularly polarized light is scattered from a rotating target, a
rotational Doppler shift (RDS) emerges from an exchange of angular momentum
between the spinning object and the electromagnetic field. Here, we used
coherently spinning molecules to generate a shift of the frequency of a
circularly polarized probe propagating through a gaseous sample. We used a
linearly polarized laser pulse to align the molecules, followed by a second
delayed pulse polarized at 45{\deg} to achieve unidirectional molecular
rotation. The measured RDS is orders of magnitude greater than previously
observed by other methods. This experiment provides explicit evidence of
unidirectional molecular rotation and paves the way for a new class of
measurements in which the rotational direction of molecular reagents may be
monitored or actively controlled.Comment: Submitted also to Nature Photonics, current status: "under
consideration
Enhanced Molecular Orientation Induced by Molecular Anti-Alignment
We explore the role of laser induced anti-alignment in enhancing molecular
orientation. A field-free enhanced orientation via anti-alignment scheme is
presented, which combines a linearly polarized femtosecond laser pulse with a
half-cycle pulse. The laser pulse induces transient anti-alignment in the plane
orthogonal to the field polarization, while the half-cycle pulse leads to the
orientation. We identify two qualitatively different enhancement mechanisms
depending on the pulse order, and optimize their effects using classical and
quantum models both at zero and non-zero temperature
Theory of Sound Propagation in Superfluid Solutions Filled Porous Media
A theory of the propagation of acoustic waves in a porous medium filled with
superfluid solution is developed. The elastic coefficients in the system of
equations are expressed in terms of physically measurable quantities. The
equations obtained describe all volume modes that can propagate in a porous
medium saturated with superfluid solution. Finally, derived equations are
applied to the most important particular case when the normal fluid component
is locked inside a highly porous media (aerogel) by viscous forces and the
velocities of two longitudinal sound modes are calculated.Comment: 13 pages, 0 figure
Meditation Awareness Training (MAT) for Work-related Wellbeing and Job Performance: A Randomised Controlled Trial
Due to its potential to concurrently improve work-related wellbeing (WRW) and job performance, occupational stakeholders are becoming increasingly interested in the applications of meditation. The present study conducted the first randomized controlled trial to assess the effects of meditation on outcomes relating to both WRW and job performance. Office-based middle-hierarchy managers (n = 152) received an eight-week meditation intervention (Meditation Awareness Training; MAT) or an active control intervention. MAT participants demonstrated significant and sustainable improvements (with strong effect sizes) over control-group participants in levels of work-related stress, job satisfaction, psychological distress, and employer-rated job performance. There are a number of novel implications: (i) meditation can effectuate a perceptual shift in how employees experience their work and psychological environment and may thus constitute a cost-effective WRW intervention, (ii) meditation-based (i.e., present-moment-focussed) working styles may be more effective than goal-based (i.e., future-orientated) working styles, and (iii) meditation may reduce the separation made by employees between their own interests and those of the organizations they work for
A review of clinical decision-making: Models and current research
Aims and objectives: The aim of this paper was to review the current literature with respect to clinical decision-making models and the educational application of models to clinical practice. This was achieved by exploring the function and related research of the three available models of clinical decision making: information processing model, the intuitive-humanist model and the clinical decision making model.
Background: Clinical decision-making is a unique process that involves the interplay between knowledge of pre-existing pathological conditions, explicit patient information, nursing care and experiential learning. Historically, two models of clinical decision making are recognised from the literature; the information processing model and the intuitive-humanist model. The usefulness and application of both models has been examined in relation the provision of nursing care and care related outcomes. More recently a third model of clinical decision making has been proposed. This new multidimensional model contains elements of the information processing model but also examines patient specific elements that are necessary for cue and pattern recognition.
Design: Literature review
Methods: Evaluation of the literature generated from MEDLINE, CINAHL, OVID, PUBMED and EBESCO systems and the Internet from 1980 – November 2005
Economic and other barriers to adopting recommendations to prevent childhood obesity: results of a focus group study with parents
Abstract Background Parents are integral to the implementation of obesity prevention and management recommendations for children. Exploration of barriers to and facilitators of parental decisions to adopt obesity prevention recommendations will inform future efforts to reduce childhood obesity. Methods We conducted 4 focus groups (2 English, 2 Spanish) among a total of 19 parents of overweight (BMI ≥ 85th percentile) children aged 5-17 years. The main discussion focused on 7 common obesity prevention recommendations: reducing television (TV) watching, removing TV from child's bedroom, increasing physically active games, participating in community or school-based athletics, walking to school, walking more in general, and eating less fast food. Parents were asked to discuss what factors would make each recommendation more difficult (barriers) or easier (facilitators) to follow. Participants were also asked about the relative importance of economic (time and dollar costs/savings) barriers and facilitators if these were not brought into the discussion unprompted. Results Parents identified many barriers but few facilitators to adopting obesity prevention recommendations for their children. Members of all groups identified economic barriers (time and dollar costs) among a variety of pertinent barriers, although the discussion of dollar costs often required prompting. Parents cited other barriers including child preference, difficulty with changing habits, lack of information, lack of transportation, difficulty with monitoring child behavior, need for assistance from family members, parity with other family members, and neighborhood walking safety. Facilitators identified included access to physical activity programs, availability of alternatives to fast food and TV which are acceptable to the child, enlisting outside support, dietary information, involving the child, setting limits, making behavior changes gradually, and parental change in shopping behaviors and own eating behaviors. Conclusions Parents identify numerous barriers to adopting obesity prevention recommendations, most notably child and family preferences and resistance to change, but also economic barriers. Intervention programs should consider the context of family priorities and how to overcome barriers and make use of relevant facilitators during program development.http://deepblue.lib.umich.edu/bitstream/2027.42/78270/1/1471-2431-9-81.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78270/2/1471-2431-9-81.pdfPeer Reviewe
Mitochondrial Protein Lipoylation and the 2-Oxoglutarate Dehydrogenase Complex Controls HIF1α Stability in Aerobic Conditions.
Hypoxia-inducible transcription factors (HIFs) control adaptation to low oxygen environments by activating genes involved in metabolism, angiogenesis, and redox homeostasis. The finding that HIFs are also regulated by small molecule metabolites highlights the need to understand the complexity of their cellular regulation. Here we use a forward genetic screen in near-haploid human cells to identify genes that stabilize HIFs under aerobic conditions. We identify two mitochondrial genes, oxoglutarate dehydrogenase (OGDH) and lipoic acid synthase (LIAS), which when mutated stabilize HIF1α in a non-hydroxylated form. Disruption of OGDH complex activity in OGDH or LIAS mutants promotes L-2-hydroxyglutarate formation, which inhibits the activity of the HIFα prolyl hydroxylases (PHDs) and TET 2-oxoglutarate dependent dioxygenases. We also find that PHD activity is decreased in patients with homozygous germline mutations in lipoic acid synthesis, leading to HIF1 activation. Thus, mutations affecting OGDHC activity may have broad implications for epigenetic regulation and tumorigenesis.This work was supported by a Wellcome Trust Senior Clinical Research Fellowship to J.A.N. (102770/Z/13/Z), Wellcome Trust Principal Research Fellowship to P.J.L. (084957/Z/08/Z), and the Medical Research Council (A.S.H.C. and C.F.). The Cambridge Institute for Medical Research is in receipt of a Wellcome Trust Strategic Award (100140).This is the final version of the article. It first appeared from Elsevier (Cell Press) via https://doi.org/10.1016/j.cmet.2016.09.01
Search Engine Similarity Analysis: A Combined Content and Rankings Approach
How different are search engines? The search engine wars are a favorite topic
of on-line analysts, as two of the biggest companies in the world, Google and
Microsoft, battle for prevalence of the web search space. Differences in search
engine popularity can be explained by their effectiveness or other factors,
such as familiarity with the most popular first engine, peer imitation, or
force of habit. In this work we present a thorough analysis of the affinity of
the two major search engines, Google and Bing, along with DuckDuckGo, which
goes to great lengths to emphasize its privacy-friendly credentials. To do so,
we collected search results using a comprehensive set of 300 unique queries for
two time periods in 2016 and 2019, and developed a new similarity metric that
leverages both the content and the ranking of search responses. We evaluated
the characteristics of the metric against other metrics and approaches that
have been proposed in the literature, and used it to (1) investigate the
similarities of search engine results, (2) the evolution of their affinity over
time, (3) what aspects of the results influence similarity, and (4) how the
metric differs over different kinds of search services. We found that Google
stands apart, but Bing and DuckDuckGo are largely indistinguishable from each
other.Comment: Shorter version of this paper was accepted in the 21st International
Conference on Web Information Systems Engineering (WISE 2020). The final
authenticated version is available online at
https://doi.org/10.1007/978-3-030-62008-0_
Economic, ecological, and social performance of conventional and organic broiler production in the Netherlands
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