102 research outputs found
Structure of exotic three-body systems
The classification of large halos formed by two identical particles and a
core is systematically addressed according to interparticle distances. The
root-mean-square distances between the constituents are described by universal
scaling functions obtained from a renormalized zero-range model. Applications
for halo nuclei, Li and Be, and for atomic He are briefly
discussed. The generalization to four-body systems is proposed.Comment: Contribution to the International workshop "Critical Stability of
Few-Body Quantum Systems". To be published in "Few-Body Systems
A new type of carbon resistance thermometer with excellent thermal contact at millikelvin temperatures
Using a new brand of commercially available carbon resistor we built a
cryogenic thermometer with an extremely good thermal contact to its thermal
environment. Because of its superior thermal contact the thermometer is
insensitive to low levels of spurious radio frequency heating. We calibrated
our thermometer down to 5mK using a quartz tuning fork He-3 viscometer and
measured its thermal resistance and thermal response time.Comment: 5 pages, 4 figure
Scaling predictions for radii of weakly bound triatomic molecules
The mean-square radii of the molecules He, HeLi,
HeLi and HeNa are calculated using a three-body model
with contact interactions. They are obtained from a universal scaling function
calculated within a renormalized scheme for three particles interacting through
pairwise Dirac-delta interaction. The root-mean-square distance between two
atoms of mass in a triatomic molecule are estimated to be of de order of
, where is the dimer and the
trimer binding energies, and is a constant (varying from
to ) that depends on the ratio between and . Considering
previous estimates for the trimer energies, we also predict the sizes of
Rubidium and Sodium trimers in atomic traps.Comment: 7 pages, 2 figure
Diagnosis and management of functional tic-like phenomena
Over the past 3 years, a global phenomenon has emerged characterized by the sudden onset and frequently rapid escalation of tics and tic-like movements and phonations. These symptoms have occurred not only in youth known to have tics or Tourette syndrome (TS), but also, and more notably, in youth with no prior history of tics. The Tourette Association of America (TAA) convened an international, multidisciplinary working group to better understand this apparent presentation of functional neurological disorder (FND) and its relationship to TS. Here, we review and summarize the literature relevant to distinguish the two, with recommendations to clinicians for diagnosis and management. Finally, we highlight areas for future emphasis and research
Metabolomics demonstrates divergent responses of two Eucalyptus species to water stress
Past studies of water stress in Eucalyptus spp. generally highlighted the role of fewer than five “important” metabolites, whereas recent metabolomic studies on other genera have shown tens of compounds are affected. There are currently no metabolite profiling data for responses of stress-tolerant species to water stress. We used GC–MS metabolite profiling to examine the response of leaf metabolites to a long (2 month) and severe (Ψpredawn < −2 MPa) water stress in two species of the perennial tree genus Eucalyptus (the mesic Eucalyptus pauciflora and the semi-arid Eucalyptus dumosa). Polar metabolites in leaves were analysed by GC–MS and inorganic ions by capillary electrophoresis. Pressure–volume curves and metabolite measurements showed that water stress led to more negative osmotic potential and increased total osmotically active solutes in leaves of both species. Water stress affected around 30–40% of measured metabolites in E. dumosa and 10–15% in E. pauciflora. There were many metabolites that were affected in E. dumosa but not E. pauciflora, and some that had opposite responses in the two species. For example, in E. dumosa there were increases in five acyclic sugar alcohols and four low-abundance carbohydrates that were unaffected by water stress in E. pauciflora. Re-watering increased osmotic potential and decreased total osmotically active solutes in E. pauciflora, whereas in E. dumosa re-watering led to further decreases in osmotic potential and increases in total osmotically active solutes. This experiment has added several extra dimensions to previous targeted analyses of water stress responses in Eucalyptus, and highlights that even species that are closely related (e.g. congeners) may respond differently to water stress and re-waterin
Racial-Ethnic Disparities in Acute Stroke Care in the Florida-Puerto Rico Collaboration to Reduce Stroke Disparities Study
Background-Racial-ethnic disparities in acute stroke care can contribute to inequality in stroke outcomes. We examined raceethnic disparities in acute stroke performance metrics in a voluntary stroke registry among Florida and Puerto Rico Get With the Guidelines-Stroke hospitals. Methods and Results-Seventy-five sites in the Florida Puerto Rico Stroke Registry (66 Florida and 9 Puerto Rico) recorded 58 864 ischemic stroke cases (2010-2014). Logistic regression models examined racial-ethnic differences in acute stroke performance measures and defect-free care (intravenous tissue plasminogen activator treatment, in-hospital antithrombotic therapy, deep vein thrombosis prophylaxis, discharge antithrombotic therapy, appropriate anticoagulation therapy, statin use, smoking cessation counseling) and temporal trends. Among ischemic stroke cases, 63% were non-Hispanic white (NHW), 18% were non-Hispanic black (NHB), 14% were Hispanic living in Florida, and 6% were Hispanic living in Puerto Rico. NHW patients were the oldest, followed by Hispanics, and NHBs. Defect-free care was greatest among NHBs (81%), followed by NHWs (79%) and Florida Hispanics (79%), then Puerto Rico Hispanics (57%) (P \u3c 0.0001). Puerto Rico Hispanics were less likely than Florida whites to meet any stroke care performance metric other than anticoagulation. Defect-free care improved for all groups during 2010-2014, but the disparity in Puerto Rico persisted (2010: NHWs=63%, NHBs=65%, Florida Hispanics=59%, Puerto Rico Hispanics=31%; 2014: NHWs=93%, NHBs=94%, Florida Hispanics=94%, Puerto Rico Hispanics=63%). Conclusions-Racial-ethnic/geographic disparities were observed for acute stroke care performance metrics. Adoption of a quality improvement program improved stroke care from 2010 to 2014 in Puerto Rico and all Florida racial-ethnic groups. However, stroke care quality delivered in Puerto Rico is lower than in Florida. Sustained support of evidence-based acute stroke quality improvement programs is required to improve stroke care and minimize racial-ethnic disparities, particularly in resource-strained Puerto Rico
Efficient algorithms for reconstructing gene content by co-evolution
<p>Abstract</p> <p>Background</p> <p>In a previous study we demonstrated that co-evolutionary information can be utilized for improving the accuracy of ancestral gene content reconstruction. To this end, we defined a new computational problem, the Ancestral Co-Evolutionary (ACE) problem, and developed algorithms for solving it.</p> <p>Results</p> <p>In the current paper we generalize our previous study in various ways. First, we describe new efficient computational approaches for solving the ACE problem. The new approaches are based on reductions to classical methods such as linear programming relaxation, quadratic programming, and min-cut. Second, we report new computational hardness results related to the ACE, including practical cases where it can be solved in polynomial time.</p> <p>Third, we generalize the ACE problem and demonstrate how our approach can be used for inferring parts of the genomes of <it>non-ancestral</it> organisms. To this end, we describe a heuristic for finding the portion of the genome ('dominant set’) that can be used to reconstruct the rest of the genome with the lowest error rate. This heuristic utilizes both evolutionary information and co-evolutionary information.</p> <p>We implemented these algorithms on a large input of the ACE problem (95 unicellular organisms, 4,873 protein families, and 10, 576 of co-evolutionary relations), demonstrating that some of these algorithms can outperform the algorithm used in our previous study. In addition, we show that based on our approach a ’dominant set’ cab be used reconstruct a major fraction of a genome (up to 79%) with relatively low error-rate (<it>e.g.</it> 0.11). We find that the ’dominant set’ tends to include metabolic and regulatory genes, with high evolutionary rate, and low protein abundance and number of protein-protein interactions.</p> <p>Conclusions</p> <p>The <it>ACE</it> problem can be efficiently extended for inferring the genomes of organisms that exist today. In addition, it may be solved in polynomial time in many practical cases. Metabolic and regulatory genes were found to be the most important groups of genes necessary for reconstructing gene content of an organism based on other related genomes.</p
Television device ecologies, prominence and datafication: the neglected importance of the set-top box
A key element of the infrastructure of television now consists of various Internet-connected devices, which play an increasingly important role in the distribution, selection and recommendation of content to users. The aim of this article is to locate the emergence of streaming devices within a longer timeframe of television hardware devices and infrastructures, by focusing on the evolution of one crucial category of such devices, television set-top boxes (STBs). STBs are a taken-for-granted part of many people’s homes across the world, and their global presence and importance are still growing. However, they (and television hardware devices more generally) have been very rarely analysed in television and media studies. To address this lacuna, we trace the development of STBs, delineate changing patterns of ownership and control in STB markets and outline the diverse forms and functions of STBs. We then show how analysis of STBs enriches understanding of two key recent developments in television: increasing battles over prominence and discoverability in a newly abundant video landscape and the collection, analysis and exchange of viewer data by businesses. In doing so, the article shows the importance of television hardware in shaping television as a social and cultural institution
Adaptive Radiation in Mediterranean Cistus (Cistaceae)
lineage consists of
12 species primarily distributed in Mediterranean habitats and
is herein subject to analysis. lineages), which display asymmetric
characteristics: number of species (2 vs. 10), leaf morphologies
(linear vs. linear to ovate), floral characteristics (small,
three-sepalled vs. small to large, three- or five-sepalled
flowers) and ecological attributes (low-land vs. low-land to
mountain environments). A positive phenotype-environment
correlation has been detected by historical reconstructions of
morphological traits (leaf shape, leaf labdanum content and leaf
pubescence). Ecological evidence indicates that modifications of
leaf shape and size, coupled with differences in labdanum
secretion and pubescence density, appear to be related to
success of new species in different Mediterranean habitats.
- …