318 research outputs found
Scaling Properties of the Giant Dipole Resonance Width in Hot Rotating nuclei
We study the systematics of the giant dipole resonance width in hot
rotating nuclei as a function of temperature , spin and mass . We
compare available experimental results with theoretical calculations that
include thermal shape fluctuations in nuclei ranging from A=45 to A=208. Using
the appropriate scaled variables, we find a simple phenomenological function
which approximates the global behavior of the giant dipole
resonance width in the liquid drop model. We reanalyze recent experimental and
theoretical results for the resonance width in Sn isotopes and Pb.Comment: LaTeX, 4 pages with 4 figures (to appear in Phys. Rev. Lett.
Radial Flow in Au+Au Collisions at E=0.25-1.15 A GeV
A systematic study of energy spectra for light particles emitted at
midrapidity from Au+Au collisions at E=0.25-1.15 A GeV reveals a significant
non-thermal component consistent with a collective radial flow. This component
is evaluated as a function of bombarding energy and event centrality.
Comparisons to Quantum Molecular Dynamics (QMD) and Boltzmann-Uehling-Uhlenbeck
(BUU) models are made for different equations of state.Comment: 10 pages of text and 4 figures (all ps files in a uuencoded package)
The AFLOW Fleet for Materials Discovery
The traditional paradigm for materials discovery has been recently expanded
to incorporate substantial data driven research. With the intent to accelerate
the development and the deployment of new technologies, the AFLOW Fleet for
computational materials design automates high-throughput first principles
calculations, and provides tools for data verification and dissemination for a
broad community of users. AFLOW incorporates different computational modules to
robustly determine thermodynamic stability, electronic band structures,
vibrational dispersions, thermo-mechanical properties and more. The AFLOW data
repository is publicly accessible online at aflow.org, with more than 1.7
million materials entries and a panoply of queryable computed properties. Tools
to programmatically search and process the data, as well as to perform online
machine learning predictions, are also available.Comment: 14 pages, 8 figure
Physical education undergraduate studentsβ perceptions of their learning using the jigsaw learning method
Recognising the limited research around the use of cooperative learning in higher education, this case study sought to explore physical education studentsβ perceptions of learning using the jigsaw learning method. It examined the impact of two different aesthetic activities and two different groupings on studentsβ perceptions of their learning. A purposive sample of 36 third-year undergraduates was selected for the study. Data were collected using focus group interviews and reflective journals. Inductive analysis illustrated studentsβ perceptions of their own and othersβ abilities, studentsβ empathy towards their peers, and how their perceptions of gymnastics and dance impacted on their perceptions of learning. Students felt that heterogeneous and friendship groupings have the potential to encourage high-order social and cognitive learning. However, those students with limited psychomotor abilities appear to be better served in friendship groupings to facilitate such learning. Students also favoured the βstructuredβ nature of gymnastics in comparison to dance for their own teaching and learning purposes. Irrespective of aesthetic activity or grouping utilised, students felt their psychomotor learning was limited. It is recommended that university staff consider using a mixture of groupings with a single cohort dependent on the practical ability of students and the use of more βstructuredβ activities. In doing so, studentsβ perceptions of their social, cognitive and psychomotor learning may improve and thereby encourage greater and more effective use of this innovative method in schools
Identification and Characterization of a Mef2 Transcriptional Activator in Schistosome Parasites
Myocyte enhancer factor 2 protein (Mef2) is an evolutionarily conserved activator of transcription that is critical to induce and control complex processes in myogenesis and neurogenesis in vertebrates and insects, and osteogenesis in vertebrates. In Drosophila, Mef2 null mutants are unable to produce differentiated muscle cells, and in vertebrates, Mef2 mutants are embryonic lethal. Schistosome worms are responsible for over 200 million cases of schistosomiasis globally, but little is known about early development of schistosome parasites after infecting a vertebrate host. Understanding basic schistosome development could be crucial to delineating potential drug targets. Here, we identify and characterize Mef2 from the schistosome worm Schistosoma mansoni (SmMef2). We initially identified SmMef2 as a homolog to the yeast Mef2 homolog, Resistance to Lethality of MKK1P386 overexpression (Rlm1), and we show that SmMef2 is homologous to conserved Mef2 family proteins. Using a genetics approach, we demonstrate that SmMef2 is a transactivator that can induce transcription of four separate heterologous reporter genes by yeast one-hybrid analysis. We also show that Mef2 is expressed during several stages of schistosome development by quantitative PCR and that it can bind to conserved Mef2 DNA consensus binding sequences
Effect of ecological factors on germination of horse purslane (Trianthema portulacastrum)
Effects of resuscitation with crystalloid fluids on cardiac function in patients with severe sepsis
<p>Abstract</p> <p>Background</p> <p>The use of hypertonic crystalloid solutions, including sodium chloride and bicarbonate, for treating severe sepsis has been much debated in previous investigations. We have investigated the effects of three crystalloid solutions on fluid resuscitation in severe sepsis patients with hypotension.</p> <p>Methods</p> <p>Ninety-four severe sepsis patients with hypotension were randomly assigned to three groups. The patients received the following injections within 15 min at initial treatment: Ns group (n = 32), 5 ml/kg normal saline; Hs group (n = 30), with 5 ml/kg 3.5% sodium chloride; and Sb group (n = 32), 5 ml/kg 5% sodium bicarbonate. Cardiac output (CO), systolic blood pressure, mean arterial pressure (MAP), body temperature, heart rate, respiratory rate and blood gases were measured.</p> <p>Results</p> <p>There were no differences among the three groups in CO, MAP, heart rate or respiratory rate during the 120 min trial or the 8 hour follow-up, and no significant differences in observed mortality rate after 28 days. However, improvement of MAP and CO started earlier in the Sb group than in the Ns and Hs groups. Sodium bicarbonate increased the base excess but did not alter blood pH, lactic acid or [HCO<sub>3</sub>]<sup>- </sup>values; and neither 3.5% hypertonic saline nor 5% sodium bicarbonate altered the Na<sup>+</sup>, K<sup>+</sup>, Ca<sup>2+ </sup>or Cl<sup>- </sup>levels.</p> <p>Conclusion</p> <p>All three crystalloid solutions may be used for initial volume loading in severe sepsis, and sodium bicarbonate confers a limited benefit on humans with severe sepsis.</p> <p>Trial registration</p> <p>ISRCTN36748319.</p
Microfluidics: reframing biological enquiry
The underlying physical properties of microfluidic tools have led to new biological insights through the development of microsystems that can manipulate, mimic and measure biology at a resolution that has not been possible with macroscale tools. Microsystems readily handle sub-microlitre volumes, precisely route predictable laminar fluid flows and match both perturbations and measurements to the length scales and timescales of biological systems. The advent of fabrication techniques that do not require highly specialized engineering facilities is fuelling the broad dissemination of microfluidic systems and their adaptation to specific biological questions. We describe how our understanding of molecular and cell biology is being and will continue to be advanced by precision microfluidic approaches and posit that microfluidic tools - in conjunction with advanced imaging, bioinformatics and molecular biology approaches - will transform biology into a precision science
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