Diffusion of finite-size particles in confined geometries

The diffusion of finite-size hard-core interacting particles in two- or three-dimensional confined domains is considered in the limit that the confinement dimensions become comparable to the particle’s dimensions. The result is a nonlinear diffusion equation for the one-particle probability density function, with an overall collective diffusion that depends on both the excluded-volume and the narrow confinement. By including both these effects the equation is able to interpolate between severe confinement (for example, single-file diffusion) and unconfined diffusion. Numerical solutions of both the effective nonlinear diffusion equation and the stochastic particle system are presented and compared. As an application, the case of diffusion under a ratchet potential is considered, and the change in transport properties due to excluded-volume and confinement effects is examined

Jets in 200 GeV p+p and d+Au collisions from the STAR experiment at RHIC

Full jet reconstruction in heavy-ion collisions is a promising tool for the quantitative study of properties of the dense medium produced at RHIC. Measurements of d+Au collisions are important to disentangle initial state nuclear effects from medium-induced kT broadening and jet quenching. Study of jet production and properties in d+Au in combination with similar studies in p+p is an important baseline measurement needed to better understand heavy-ion results. We present mid-rapidity inclusive jet pT spectra and di-jet correlations (kT) in 200 GeV p+p and d+Au collisions from the 2007-2008 RHIC run. We discuss the methods used to correct the data for detector effects and for background in d+Au collisions.Comment: 4 pages, 5 figures. To appear in Hot Quarks 2010 conference proceeding

Overview on jet results from STAR

Full jet reconstruction allows access to the parton kinematics over a large energy domain and can be used to constrain the mechanisms of energy loss in heavy-ion collisions. Such measurements are challenging at RHIC, due to the high-multiplicity environments created in heavy-ion collisions. In these proceedings, we report an overview of the results on full jet reconstruction obtained by the STAR experiment. Jet measurements in 200 GeV p+p show that jets are calibrated pQCD probes and provide a baseline for jet measurements in Au+Au collisions. Inclusive differential jet production cross sections and ratios are reported for central 200 GeV Au+Au collisions and compared to p+p. We also present measurements of fully reconstructed di-jets at mid-rapidity, and compare spectra and fragmentation functions in p+p and central Au+Au collisions.Comment: Proceedings for the 26th WWND conferenc

Weight gain in patients after therapy for hyperthyroidism

Objective. To determine the prevalence of obesity following therapy for hyperthyroidism and to assess the contributing factors associated with an undesirable weight gain.Design. A retrospective analysis was undertaken of clinical records for 160 hyperthyroid patients attending an endocrine clinic in Bloemfontein (1994 - 2001).Results. Of the 160 patients, 143 had Graves' disease and 17 patients had multinodular goitre. Most of our patients (N = 147) were treated with radioiodine, 10 patients with carbimazole and 3 patients had thyroidectomy. The median weight gain 6 months after therapy was 5.0 kg, after 12 months 9.0 kg, and after 24 months 12 kg, whereafter body mass stabilised. Before therapy 27.5% of patients had a body mass index (BMI) of < 22 kg/m2, 29.4% were overweight (BMI > 25 kg/m2) and 19.3% were obese (BMI > 30 kg/m2). Two years after treatment only 8.7% of patients had a BMI of < 22 kg/m2, 27.5% had a BMI > 25 kg/m2, and 51.3% had become obese. The main factors associated with weight gain 24 months after therapy were poor control of thyroid function on replacement therapy, diagnosis of Graves' disease and need for thyroxine replacement.Conclusion. This study has shown a large increase (32%) in the prevalence of obesity following treatment for hyperthyroidism. The main weight gain was during the first 2 years after therapy. The main factors contributing to excessive weight gain were need for replacement therapy and poor control of thyroid function

Carrier mobility and scattering lifetime in electric double-layer gated few-layer graphene

We fabricate electric double-layer field-effect transistor (EDL-FET) devices on mechanically exfoliated few-layer graphene. We exploit the large capacitance of a polymeric electrolyte to study the transport properties of three, four and five-layer samples under a large induced surface charge density both above and below the glass transition temperature of the polymer. We find that the carrier mobility shows a strong asymmetry between the hole and electron doping regime. We then employ ab-initio density functional theory (DFT) calculations to determine the average scattering lifetime from the experimental data. We explain its peculiar dependence on the carrier density in terms of the specific properties of the electrolyte we used in our experiments.Comment: 6 pages, 3 figure

Electromagnetic and thermal homogenisation of an electrical machine slot

In this paper we propose an original technique based on the finite element method to couple electromagnetic and thermal homogenisation of multiturn windings. The model accurately accounts for skin and proximity effects considering the temperature dependence of electrical resistivity. We validate the approach by modelling a reference electrical machine open slot with representative boundary conditions. The case study refers to a particular wire shape and winding periodic configuration but the method can be applied to any symmetrical wire shape. The homogenisation allows us to efficiently evaluate the hot- spot temperature within the slot. The solution provided by the homogenised model proves to be very accurate over a large range of frequencies, when compared to the results using a fine model where all the conductors are physically reproduced

A low-cost classroom-oriented educational robotics system

Over the past few years, there has been a growing interest in using robots in education. The use of these tangible devices in combination with problem-based learning activities results in more motivated students, higher grades and a growing interest in the STEM areas. However, most educational robotics systems still have some restrictions like high cost, long setup time, need of installing software in children's computers, etc. We present a new, Iow-cost, classroom-oriented educational robotics system that does not require the installation of any software. It can be used with computers, tablets or smartphones. It also supports multiple robots and the system can be setup and is ready to be used in under 5 minutes. The robotics system that will be presented has been successfully used by two classes of 3rd and 4th graders. Besides improving mathematical reasoning, the system can be employed as a motivational tool for any subject

Effects of environmental, living space and climate variability on the utilization of impregnated bed nets in west Cameroon: A community based survey for policy implementation

Background: Despite the fact that Long Lasting Impregnated Mosquito Net (LLIN) represents one of the most effective tools in fighting malaria, its use remains limited. Our study aimed at determining how environmental, household characteristics and climate affect bed net use. Methodology: A cross sectional descriptive and analytic study was carried out from January to April 2014 in Mifi health district. Data collected were collected in households during a face to face interview with standard household questionnaires, entered and analyzed using Epi Info software version 3.5.3. Graphics and tables were obtained using MS Excel and Word. Results: Of the 317 participants interviewed, average age was 33.23 years (SD = 10.80) and female sex predominant (85.2%). Most participants had attended secondary education 53.6% (n= 170), married marital status was most represented (58.1%; n= 185).75.4% (n=239) of households had at least 1 LLIN and average district coverage estimated to 1 LLIN for 3.3 persons. 78% of occupants in households with at least one LLIN had slept under the night before the survey. The presence of a ceiling in a house reduced net usage by 2.5% (p = 0.67) compared to house lacking ceiling. Standing waters around the compound increased net utilization rate to 16.6% (p = 0.03), whereas the presence of a covered well decreased the rate by 1.4% (p = 0.86). The dry season was identified as the period during which 86.8% (n= 239) of respondents sleep less under a net. Heat (57.60% n = 138/239), increased choking (2.5%), reduction in vector breeding sites (39.90%; n = 95) were cited as main reasons. Conclusion: Although classified as zone of continuous transmission, our findings indicate that bed net usage by our study population depends on environmental, household characteristics and climate. There is therefore an urgent need to develop strategic communication and sensitization campaigns coupled to environmental management to help scale up and optimize malaria burden reductio