423 research outputs found
Turbulent transport of impurities and their effect on energy confinement
By presenting linear and nonlinear gyrokinetic studies, based on a balanced
neutral beam injection deuterium discharge from the DIII-D tokamak, we
demonstrate that impurities alter the scaling of the transport on the charge
and mass of the main species, and even more importantly, they can dramatically
change the energy transport even in relatively small quantities. A poloidally
varying equilibrium electrostatic potential can lead to a strong reduction or
sign change of the impurity peaking factor due to the combined effect of the
in-out impurity density asymmetry and the EXB drift of impurities. We present
an approximate expression for the impurity peaking factor and demonstrate that
impurity peaking is not significantly affected by impurity self-collisions.Comment: Accepted for publication in Plasma Physics and Controlled Fusio
When the frame fits the social picture:The effects of framed social norm messages on healthy and unhealthy food consumption
We investigated the influence of framed norm messages about food consumption on motivation to consume, and actual consumption of, healthy and unhealthy foods. We proposed that the effects of positive and negative message frames would vary by the type of underlying norms (i.e., injunctive, descriptive). More specifically, based on information processing theories, it was expected that injunctive norms would be more effective when framed negatively compared with positively, while the opposite was expected for descriptive norms. In both experiments, participants were randomly assigned to one of four framed social norm conditions or a no-norm control condition. In experiment 1, motivation to consume healthy and unhealthy foods was assessed by means of both indirect and self-report measures. In experiment 2, actual food consumption was assessed. In both experiments, the predicted interaction was found. Results show that injunctive norms benefit from a negative (vs. Positive) frame, while preliminary evidence suggests the opposite for descriptive norms
Groovy and Gnarly: Surface Wrinkles as a Multifunctional Motif for Terrestrial and Marine Environments
From large ventral pleats of humpback whales to nanoscale ridges on flower petals, wrinkled structures are omnipresent, multifunctional, and found at hugely diverse scales. Depending on the particulars of the biological system—its environment, morphology, and mechanical properties—wrinkles may control adhesion, friction, wetting, or drag; promote interfacial exchange; act as flow channels; or contribute to stretching, mechanical integrity, or structural color. Undulations on natural surfaces primarily arise from stress-induced instabilities of surface layers (e.g., buckling) during growth or aging. Variation in the material properties of surface layers and in the magnitude and orientation of intrinsic stresses during growth lead to a variety of wrinkling morphologies and patterns which, in turn, reflect the wide range of biophysical challenges wrinkled surfaces can solve. Therefore, investigating how surface wrinkles vary and are implemented across biological systems is key to understanding their structure-function relationships. In this work, we synthesize the literature in a metadata analysis of surface wrinkling in various terrestrial and marine organisms to review important morphological parameters and classify functional aspects of surface wrinkles in relation to the size and ecology of organisms. Building on our previous and current experimental studies, we explore case studies on nano/micro-scale wrinkles in biofilms, plant surfaces, and basking shark filter structures to compare developmental and structure-vs-function aspects of wrinkles with vastly different size scales and environmental demands. In doing this and by contrasting wrinkle development in soft and hard biological systems, we provide a template of structure-function relationships of biological surface wrinkles and an outlook for functionalized wrinkled biomimetic surfaces
COLECCIONES FOTOGRÁFICAS DEL MUSEO Y PARQUE ARQUEOLÓGICO CUEVA PINTADA [Material gráfico]
Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201
The Surgical Infection Society revised guidelines on the management of intra-abdominal infection
Background: Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations.
Methods: Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council.
Results: This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included.
Summary: The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline
Measurement of the diffractive structure function in deep inelastic scattering at HERA
This paper presents an analysis of the inclusive properties of diffractive
deep inelastic scattering events produced in interactions at HERA. The
events are characterised by a rapidity gap between the outgoing proton system
and the remaining hadronic system. Inclusive distributions are presented and
compared with Monte Carlo models for diffractive processes. The data are
consistent with models where the pomeron structure function has a hard and a
soft contribution. The diffractive structure function is measured as a function
of \xpom, the momentum fraction lost by the proton, of , the momentum
fraction of the struck quark with respect to \xpom, and of . The \xpom
dependence is consistent with the form \xpoma where
in all bins of and
. In the measured range, the diffractive structure function
approximately scales with at fixed . In an Ingelman-Schlein type
model, where commonly used pomeron flux factor normalisations are assumed, it
is found that the quarks within the pomeron do not saturate the momentum sum
rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil
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