1,210 research outputs found

    Selective perspectives of implementing computer technology in K-12 education in the State of Kuwait

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    Through this research, the author examined the opinions and attitudes of virtually every segment of the Kuwaiti society (i.e., administrators, teachers, students, parents, and community members) toward the use of computers and technology in K-12 education. A Likert scale questionnaire was the primary vehicle for data collection. This questionnaire was designed to find out value judgments for issues such as implementing computer technology as an independent subject in K-12 schools versus integrating computer technology in all other subjects. A stratified random sample was secured from all five Kuwaiti govemorates (i.e., regions) from 70 schools. The overall number of participants who received the study\u27s survey was 1,190. Of the questionnaires distributed, 1, 165 were returned, for a return rate of 97.89 percent. Both descriptive statistics procedures (e.g., frequency, mean, and standard deviation) and inferential statistics procedures ( e.g., factor analysis, analysis of variance (ANOVA), Tukey\u27s HSD multiple comparisons, and t-test) were conducted

    Theory of a Continuous Hc2_{c2} Normal-to-Superconducting Transition

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    I study the Hc2H_{c2} transition within the Ginzburg-Landau model, with mm-component order parameter ψi\psi_i. I find a renormalized fixed point free energy, exact in m→∞m\rightarrow\infty limit, suggestive of a 22nd-order transition in contrast to a general belief of a 11st-order transition. The thermal fluctuations for H≠0H\neq 0 force one to consider an infinite set of marginally relevant operators for d<duc=6d<d_{uc}=6. I find dlc=4d_{lc}=4, predicting that the ODLRO does not survive thermal fluctuations in d=2,3d=2,3. The result is a solution to a critical fixed point that was found to be inaccessible within ϵ=6−d\epsilon=6-d-expansion, previously considered in E.Brezin, D.R.Nelson, A.Thiaville, Phys.Rev.B {\bf 31}, 7124 (1985), and was interpreted as a 11st-order transition.Comment: 4 pages, self-unpacking uuencoded compressed postscript file with a figure already inside text; to appear in Phys. Rev. Lett

    First-Order Melting of a Moving Vortex Lattice: Effects of Disorder

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    We study the melting of a moving vortex lattice through numerical simulations with the current driven 3D XY model with disorder. We find that there is a first-order phase transition even for large disorder when the corresponding equilibrium transition is continuous. The low temperature phase is an anisotropic moving glass.Comment: Important changes from original version. Finite size analysis of results has been added. Figure 2 has been changed. There is a new additional Figure. To be published in Physical Review Letter

    Nonlocal Conductivity in the Vortex-Liquid Regime of a Two-Dimensional Superconductor

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    We have simulated the time-dependent Ginzburg-Landau equation with thermal fluctuations, to study the nonlocal dc conductivity of a superconducting film. Having examined points in the phase diagram at a wide range of temperatures and fields below the mean-field upper critical field, we find a portion of the vortex-liquid regime in which the nonlocal ohmic conductivity in real space is negative over a distance several times the spacing between vortices. The effect is suppressed when driven beyond linear response. Earlier work had predicted the existence of such a regime, due to the high viscosity of a strongly-correlated vortex liquid. This behavior is clearly distinguishable from the monotonic spatial fall-off of the conductivity in the higher temperature or field regimes approaching the normal state. The possibilities for experimental study of the nonlocal transport properties are discussed.Comment: 18 pages, revtex, 6 postscript figure

    Comment on `Strong Vortex Liquid Correlation' from Multiterminal Measurements on Untwinned YBa2_2Cu3_3O7−δ_{7-\delta} Single Crystals'

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    A.Rydh and \"O.Rapp [Phys. Rev. Lett. {\bf 86}, 1873 (2001).] claim that the vortex liquid in untwinned YBa2_2Cu3_3O7−δ_{7-\delta} crystals is correlated above the melting transition, in striking contrast to previous work [D.L\'opez {\it et al.}, Phys. Rev. Lett. {\bf 76}, 4034 (1996).]. In this Comment we present new measurements using the same experimental technique on twinned and untwinned YBa2_2Cu3_3O7−δ_{7-\delta} crystals with similar overall characteristics as those reported by Rydh and Rapp . The comparison of the vortex correlation response in both cases indicates that the central conclusion of their work is not correct. Our results reconfirm the work by L\'opez {\it et al.} and points on the origin of the misinterpretation in the work of Rydh and Rapp.Comment: comment on A.Rydh and \"O.Rapp, Phys. Rev. Lett. {\bf 86}, 1873 (2001). accepted in Phys. Rev. Let

    First-Order Vortex Lattice Melting and Magnetization of YBa2_2Cu3_3O$_{7-\delta}

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    We present the first non-mean-field calculation of the magnetization M(T)M(T) of YBa2_2Cu3_3O7−δ_{7-\delta} both above and below the flux-lattice melting temperature Tm(H)T_m(H). The results are in good agreement with experiment as a function of transverse applied field HH. The effects of fluctuations in both order parameter ψ(r)\psi({\bf r}) and magnetic induction BB are included in the Ginzburg-Landau free energy functional: ψ(r)\psi({\bf r}) fluctuates within the lowest Landau level in each layer, while BB fluctuates uniformly according to the appropriate Boltzmann factor. The second derivative (∂2M/∂T2)H(\partial^2 M/\partial T^2)_H is predicted to be negative throughout the vortex liquid state and positive in the solid state. The discontinuities in entropy and magnetization at melting are calculated to be ∼0.034 kB\sim 0.034\, k_B per flux line per layer and ∼0.0014\sim 0.0014~emu~cm−3^{-3} at a field of 50 kOe.Comment: 11 pages, 4 PostScript figures in one uuencoded fil

    Osteosarcoma of the femur in early adult: a case report

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    Osteosarcomas are primary malignant tumors of bone that are characterized by the production of osteoid or immature bone by the malignant cells. Osteosarcomas are uncommon tumors. Most articles reveal difficulty in diagnosing osteosarcoma in early stage due to its resemblance to benign lesion. That’s why we prefer to do case report for documentation. Diagnosis of the tumor is important especially in early stages for improving prognosis. This case report is of a 21 years old female who presented at Primary Health Care Centre with swelling above right knee post trauma a month ago. Previously she was diagnosed as Non ossifying fibroma (which is a benign lesion and uncommon to change to malignant lesion) at the same site in 2017.

    Rheumatoid arthritis onset after COVID-19 infection: a case report

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    At the end of 2019, coronavirus disease (COVID-19) outbreak is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). Worldwide researchers and physician try to explore the mechanisms of damage induced by virus, they focus on the short-term and long-term immune-mediated consequences induced by the virus infection. Every day discover a new pathological condition induced by virus and new symptoms and disease may occur after recovery from disease. Our case report is 41 years old, Indian lady who presented to our primary health care centre complaining of multiple small hand joints pain, both elbows and knees pain with swelling of them and prolonged morning stiffness, diagnosed seropositive rheumatoid arthritis (RA) (arthritis, positive rheumatoid factor (RF), and X-ray changes) after 1 month recovery from COVID-19 infection. She did not have any joint pain and she had negative RF before COVID-19 infection with no family history of RA

    Characterization of Contamination Around the Largest Lead Smelter in Egypt Carried Out Through a Cooperation Program between USA and Egypt

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    The Government of Egypt together USAID aimed to reduce the impact of lead smelters on the environment. The major site was in Shoubra El-Kheima, where the Awadulla Secondary Lead Smelter is situated.  The Awadulla Family Company owns about 70% of the lead smelters in Egypt. This work presents the results and conclusions of a detailed on-site and off-site contaminant characterization of the Awadulla Secondary Lead Smelter.    As part of the characterization of the smelter site, soil and dust samples were collected within and near the smelter using two methods. The first consisted of collecting bulk dust and soil samples from the floor and ground in the direct vicinity of the smelter. The second involved using wet wipes to collect dust samples from walls, smooth floors, duct work, window and ledges.  The results indicate that the most contaminated soils can be found in industrial areas and on public streets in Shoubra El-Kheima. The highest lead concentrations of more than 780,000 mg.kg-1 were found inside the smelter site. Concentrations at the El-Mahy Smelter nearby reached 302,275 mg.kg-1. Residential areas had considerably lower lead levels in soil and dust.  Samples of surface water and groundwater were collected and tested for lead contamination.  Only three samples had lead concentrations above detection limits, indicating water contamination is not a problem. The maximum area affected by deposition of lead from the Awadulla smelter appears to be no more than 500 m all around the smelter. The plan calls for moving the smelters to a new industrial area called Abu Zaabal.  This move will leave behind existing structures that are highly contaminated with lead dust.  El Gobierno egipcio, junto con USAID (Agencia Estadounidense Para el Desarrollo Internacional), pretendía reducir el impacto de los hornos de fundición de plomo sobre el medio ambiente. El emplazamiento principal está en Shoubra El-Kheima, donde se encuentra el horno de fundición de plomo secundario de Awadulla. La empresa de la familia Awadulla posee aproximadamente el 70% de los hornos de fundición de plomo en Egipto. Este trabajo presenta los resultados y las conclusiones de un detallado estudio de caracterización de contaminantes en el emplazamiento y fuera del emplazamiento del horno de fundición de plomo secundario de Awadulla. Como parte de la caracterización del emplazamiento del horno de fundición, se recogieron muestras de terreno y de polvo dentro de y cerca del horno de fundición usando dos métodos. Por una parte, se recogieron muestras de polvo y de terreno a granel del suelo y la tierra en las inmediaciones directas del horno de fundición y por otra, se recogieron muestras de polvo de paredes, suelos lisos, canalizaciones, ventanas y repisas utilizando toallitas húmedas. Los resultados indican que los terrenos más contaminados se encuentran en zonas industriales y en calles públicas en Shoubra El-Kheima. Las concentraciones más elevadas, de más de 780.000 mg/kg, están dentro del emplazamiento del horno de fundición. Las concentraciones en el cercano horno de fundición de El-Mahy eran de 302.275 mg/kg. Las zonas residenciales mostraron niveles de plomo considerablemente inferiores en terreno y polvo. Se recogieron muestras de agua superficial y agua subterránea y se les realizaron pruebas para detectar contaminación por plomo. Solamente tres muestras presentaban concentraciones de plomo por encima de los límites de detección, indicando que la contaminación del agua no supone un problema. El área máxima afectada por deposición de plomo procedente del horno de fundición de Awadulla parece no ser superior a 500 metros alrededor del horno de fundición. El plan requiere trasladar los hornos de fundición a una nueva zona industrial llamada Abu Zaabal. Este traslado dejará atrás estructuras existentes que están altamente contaminadas con polvo de plomo.En collaboration avec l'USAID, le Gouvernement égyptien a élaboré un projet visant à réduire l'impact des fonderies de plomb sur l'environnement. La principale fonderie concernée était l'Awadulla Secondary Lead Smelter située à Shoubra El-Kheima. L'Awadulla Family Company détient environ 70 % des fonderies de plomb en Egypte. Cet article présente les résultats et les conclusions d'une étude de caractérisation de contaminants sur site et hors site menée sur le site de l'Awadulla Secondary Lead Smelter. Dans le cadre de cette étude, des échantillons de terre et de poussière ont été recueillis dans et à proximité de la fonderie selon deux méthodes. La première méthode a consisté à recueillir des échantillons en vrac de poussière et de terre sur le sol de la fonderie et à proximité immédiate de celle-ci. La seconde méthode a consisté à recueillir des échantillons de poussière sur les murs, les sols lisses, les conduites, les fenêtres et les rebords de celles-ci, à l'aide de chiffons humides. Les résultats ont indiqué que les sols les plus contaminés étaient localisés dans les zones industrielles et les rues de Shoubra El-Kheima. Les plus fortes concentrations, supérieures à 780 000 mg/kg, ont été relevées sur le site même de la fonderie. Des concentrations de 302 275 mg/kg ont été constatées à la fonderie voisine d'El-Mahy. Les zones résidentielles ont affiché des taux de plomb nettement plus faibles dans le sol et la poussière. Des échantillons des eaux de surface et des eaux souterraines ont été recueillis et analysés afin de déterminer la contamination au plomb. Seuls trois échantillons ont présenté des concentrations en plomb supérieures aux limites de détection, indiquant que la contamination de l'eau n'était pas inquiétante. Le périmètre touché par des dépôts de plomb de la fonderie Awadulla semble être de 500 mètres autour de la fonderie maximum. Le programme préconise le déplacement des fonderies dans une nouvelle zone industrielle dénommée Abu Zaabal. Cela implique l'abandon des structures existantes fortement contaminées par de la poussière de plomb
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