277 research outputs found
Strangeness and the discovery of quark-gluon plasma
Strangeness flavor yield s and the entropy yield S are the observables of the
deconfined quark-gluon state of matter which can be studied in the entire
available experimental energy range at AGS, SPS, RHIC, and, in near future, at
the LHC energy range. We present here a comprehensive analysis of strange, soft
hadron production as function of energy and reaction volume. We discuss the
physical properties of the final state and argue how evidence about the
primordial QGP emerges.Comment: 16 pages: Invited talk at 5th International Conference on Physics and
Astrophysics of Quark Gluon Plasma, February 8 - 12, 2005, Salt Lake City,
Kolkata, India, to appear in: Journal of Physics: Conference Serie
Emergent low-symmetry phases and large property enhancements in Ferroelectric KNbO3 bulk crystals
The design of new or enhanced functionality in materials is traditionally viewed as requiring the discovery of new chemical compositions through synthesis. Large property enhancements may however also be hidden within already well-known materials, when their structural symmetry is lowered from equilibrium through a small local strain or field. This work reports on the discovery of enhanced material properties associated with a new metastable phase of monoclinic symmetry within bulk KNbO3. This phase is found to co-exist with the nominal orthorhombic phase at room temperature, and is both induced by and stabilized with local strains generated by a network of ferroelectric domain walls. While the local microstructural shear strain involved is only ~0.017%, the concurrent symmetry reduction results in an optical second harmonic generation response that is over 550% higher at room temperature.Moreover, the meandering walls of the low symmetry domains also exhibit enhanced electrical conductivity on the order of 1 S m-1. This discovery reveals a potential new route to local engineering of significant property enhancements and conductivity through symmetry lowering in bulk ferroelectric crystals
An Experimental Exploration of the QCD Phase Diagram: The Search for the Critical Point and the Onset of De-confinement
The QCD phase diagram lies at the heart of what the RHIC Physics Program is
all about. While RHIC has been operating very successfully at or close to its
maximum energy for almost a decade, it has become clear that this collider can
also be operated at lower energies down to 5 GeV without extensive upgrades. An
exploration of the full region of beam energies available at the RHIC facility
is imperative. The STAR detector, due to its large uniform acceptance and
excellent particle identification capabilities, is uniquely positioned to carry
out this program in depth and detail. The first exploratory beam energy scan
(BES) run at RHIC took place in 2010 (Run 10), since several STAR upgrades,
most importantly a full barrel Time of Flight detector, are now completed which
add new capabilities important for the interesting physics at BES energies. In
this document we discuss current proposed measurements, with estimations of the
accuracy of the measurements given an assumed event count at each beam energy.Comment: 59 pages, 78 figure
Orthogonal Block Structure and Uniformly Best Linear Unbiased Estimators
Models with orthogonal block structure, OBS, have variance covariance
matrices that are linear combinations [...]info:eu-repo/semantics/publishedVersio
Effect of nutrition education and dairy group membership on nutrition knowledge, practices and diet quality for rural Kenyan farm women
The typical high-starch, low diversity diet in developing countries is associated withundernutrition, morbidity and mortality. Previous research with households inMukurwe-ini Division (Central Kenya) found that members of a community-baseddairy development group were more food secure and had higher intake of certainmicronutrients compared with non-members; however, the prevalence of inadequateintake of multiple micronutrients was high among all women. A nutrition educationintervention was developed to enhance women’s nutrition knowledge and food skills toultimately improve diet quality and micronutrient intakes for women and their families.In addition, it was proposed that the intervention effects would be greater for dairygroup members. The Mukurwe-ini study group consisted of 88 women in four dairymembership-duration categories (n=4 x 22) and non-member women (n=23). The studygroup was previously selected using chain referral sampling. For the intervention,women from each duration-group and non-member women were randomly allocated tointervention (n=55) and control (n=56) groups. Nutrition knowledge and dietary intake(24-hour recall) data were collected from all women over three weeks immediatelyprior to the intervention (baseline) and again, six months post-intervention, inindividual face-to-face interviews. The intervention encouraged food-based strategiesto improve intake of vitamin A, iron and zinc and was developed and delivered incollaboration with a Kenyan dietitian. WFood2 was used to compute food and nutrientintakes, dietary diversity and the phytate:zinc molar ratio. Descriptive statistics andlinear and logistic regressions analyses were performed using Stata10. Independent ofdairy-group membership, a larger proportion of intervention group women, comparedto control group women, had the targeted nutrition knowledge and practiced thestrategies to improve intake of vitamin A (76% vs 67%, respectively) and zinc and iron(soaked beans and maize 80% vs 13%; avoided tea with meals 67 % vs 5%,respectively). A positive effect of the intervention on dietary diversity was dependenton dairy-group membership status. Positive intervention effects on intake of vitamin Aand C were found for non-member women. This study provided evidence that certainintervention effects were dependent on poverty reduction and that all women were ableto make positive dietary changes when informed. There is a need to examine longertermimpacts of nutrition education interventions and to explore effective methods todisseminate nutrition information and food-based strategies.Key words: nutrition intervention, micronutrients, food-based strategy, rural, women,dairy, smallholder farme
Lesson Worksheets: A Tool for Developing Youth Weather and Climate Science Comprehension
At an Extension youth agricultural science center, our team developed and pilot tested a five-lesson weather and climate science curriculum for middle school–aged youths. As part of the endeavor, we conducted an item analysis of the five worksheets used across the lessons and determined relationships between worksheet scores and pretest/posttest science comprehension improvement scores. Results from 88 primarily Hispanic eighth graders indicated that worksheet performance was related to overall science comprehension, science knowledge, and weather and climate resiliency in agriculture and natural resources lesson improvement scores. Results support the use of formative scaffolding tools such as worksheets in Extension youth programming to improve youth science comprehension
Magneto-optic superlattice thin films: Fabrication, structural and magnetic characterization
During this quarter studies were extended to determine the electronic contribution to the perpendicular interface anisotropy in Co-based multilayers. Using in situ Kerr effect measurements, the influences of different transition metals (TM = Ag, Au, Cu, and Pd) on the magnetic properties of single-crystal Co films grown on Pd (111) and Au (111) surfaces are investigated. Last quarter the discovery of a large peak in the perpendicular anisotropy when approximately one monolayer of Cu or Ag is deposited on the Co surface was reported. We now have added a computer-controlled stepper-motor drive to our MBE sample transfer mechanism. The motor allows us to move the sample at a constant velocity from behind a shutter during deposition. The film, therefore, is deposited as a wedge with a linear variation of thickness across the substrate. In this way, a continuous range of coverage on a single sample is studied. The stepper motor also provides the necessary control for precisely positioning the sample in the laser beam for Kerr effect measurements at the different coverages
Radiative transfer in shrub savanna sites in Niger: Preliminary results from HAPEX-Sahel. Part 1: Modelling surface reflectance using a geometric-optical approach
To use optical remote sensing to monitor land surface-climate interactions over large areas, algorithms must be developed to relate multispectral measurements to key variables controlling the exchange of matter (water, carbon dioxide) and energy between the land surface and the atmosphere. The proportion of the ground covered by vegetation and the interception of photosynthetically active radiation (PAR) by vegetation are examples of two variables related to evapotranspiration and primary production, respectively. An areal-proportion model of the multispectral reflectance of shrub savanna, composed of scattered shrubs with a grass, forb or soil understory, predicted the reflectance of two 0.5 km(exp 2) sites as the area-weighted average of the shrub and understory or 'background' reflectances. Although the shaded crown and shaded background have darker reflectances, ignoring them in the area-weighted model is not serious when shrub cover is low and solar zenith angle is small. A submodel predicted the reflectance of the shrub crown as a function of the foliage reflectance and amount of plant material within the crown, and the background reflectance scattered or transmitted through canopy gaps (referred to as a soil-plant 'spectral interaction' term). One may be able to combine these two models to estimate both the fraction of vegetation cover and interception of PAR by green vegetation in a shrub savanna
Endoparasites in dogs diagnosed at the Veterinary Teaching Hospital (VTH)-University of Bologna, combined with clinicopathological results. A long-term retrospective secondary data study
Humans and dogs commonly share the same domestic environment. Europe, and Italy specifically, have a substantial and growing dog population. Potentially zoonotic parasites may be harbored even by dogs receiving regular veterinary care. Thus, transmission of zoonotic or potentially zoonotic parasites to owners and their families should not be underestimated. Frequently, endoparasite infections occur as a subclinical infection and clinicopathological alterations have been documented including anemia, hypoalbuminemia, and eosinophilia. The aim of this large retrospective secondary data study was to analyze coprological endoparasite results and putative risk factors obtained from owned dogs, through a 9-year-period (2011-2019). Possible associations between diagnosed endoparasites and sex, age, seasonality, and year of examination were evaluated. Additionally, parasitological diagnoses were combined to complete blood count parameters and biochemical profiles, when available, to check for any possible hematological alteration from parasitism. A total of 1,972 dogs were evaluated for endoparasites using common fecal diagnostic tests over a 9-year period. The overall proportion of endoparasite-positive animals was 10%. The most common endoparasites detected were Cystoisospora spp. (3%), Toxocara canis (2.8%), Giardia duodenalis (1.6%), and Trichuris vulpis (1.2%). Of these parasites detected, Toxocara poses the greatest zoonotic risk, while Giardia species are considered to have a low potential to be zoonotic. There was no significant diagnostic trend across the years through the study period. Dogs were more frequently diagnosed endoparasite-positive when young and during cold seasons compared to the baselines of mature dogs and warm seasons. The clinicopathological profiles indicated that parasitized dogs had mild hematological alterations. The frequency of detected potentially zoonotic endoparasites in this study highlights that the risk should not be underestimated. Parasitic infection was found to be mostly dependent on age and season. Having this information may help clinicians to develop anthelmintic protocols to reduce the risk of transmission
Science Comprehension Retention Among Youth Agriscience Students Instructed in Weather and Climate
The purpose of this article is to examine the science comprehension retention of 8th-grade science students taught a new weather and climate curriculum. The students’ middle school is part of an innovative Extension youth agricultural science center that has a mission to develop and test new teaching and learning models and curricula in agriculture and natural resources. Our curriculum was developed following a science comprehension model we created and have been testing at the center. It contained lessons on the water cycle, the greenhouse effect, measuring and analyzing precipitation and temperature data, and mitigating and adapting to weather and climate extremes in agriculture and natural resources. For each lesson, students viewed introductory PowerPoint slides, participated in an activating strategy, set up an experiment or analyzed local precipitation or temperature data, formulated hypotheses, participated in a summary activity, and completed a worksheet. We pretested 81 students, taught the curriculum over a 6-day period, and gave the posttest. We returned 2 months later to administer a follow-up to check for science comprehension retention. The students’ overall science comprehension and science knowledge, science skills, and reasoning abilities subcomponent follow-up scores were lower than their post-program test scores. Both boys and girls declined in their overall post-program test gains over the 2 months. Students also declined in their preference for learning-by-doing from post-test to follow-up. Based on these results, we made changes to the curriculum consistent with the literature on learning retention before publishing it online for youth educators
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