1,897 research outputs found

    Berry's phase in noncommutative spaces

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    We introduce the perturbative aspects of noncommutative quantum mechanics. Then we study the Berry's phase in the framework of noncommutative quantum mechanics. The results show deviations from the usual quantum mechanics which depend on the parameter of space/space noncommtativity.Comment: 7 pages, no figur

    Bound of Noncommutativity Parameter Based on Black Hole Entropy

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    We study the bound of the noncommutativity parameter in the noncommutative Schwarzschild black hole which is a solution of the noncommutative ISO(3,1) Poincare gauge group. The statistical entropy satisfying the area law in the brick wall method yields a cutoff relation which depends on the noncommutativity parameter. Requiring both the cutoff parameter and the noncommutativity parameter to be real, the noncommutativity parameter can be shown to be bounded as Θ>8.4 times102lp\Theta > 8.4\ times 10^{-2}l_{p}.Comment: LaTeX 7 pages, references added, minor correction

    The Noncommutative Anandan's Quantum Phase

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    In this work we study the noncommutative nonrelativistic quantum dynamics of a neutral particle, that possesses permanent magnetic and electric dipole momenta, in the presence of an electric and magnetic fields. We use the Foldy-Wouthuysen transformation of the Dirac spinor with a non-minimal coupling to obtain the nonrelativistic limit. In this limit, we will study the noncommutative quantum dynamics and obtain the noncommutative Anandan's geometric phase. We analyze the situation where magnetic dipole moment of the particle is zero and we obtain the noncommutative version of the He-McKellar-Wilkens effect. We demonstrate that this phase in the noncommutative case is a geometric dispersive phase. We also investigate this geometric phase considering the noncommutativity in the phase space and the Anandan's phase is obtained.Comment: 15 pages, revtex4, version to appear in Physical Review

    Comparing the Effects of Active and Passive Intradialytic Pedaling Exercises on Dialysis Efficacy, Electrolytes, Hemoglobin, Hematocrit, Blood Pressure and Health-Related Quality of Life

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    Background: The effect of exercise during hemodialysis has been a controversial issue, however, there are just few studies about the effect of active exercise during hemodialysis. Objectives: This study aimed to compare the effects of passive and active intradialytic pedaling exercises on dialysis efficacy, electrolytes, hemoglobin, hematocrit, blood pressure and health-related quality of life in hemodialysis patients. Patients and Methods: This quasi-experimental study was conducted on 16 hemodialysis patients in Akhavan hemodialysis center in Kashan from April to November 2013. Active or passive intradialytic pedaling exercise was performed using a Mini-Bike for 30 minutes during the first two hours of the dialysis sessions. The quality of life (QOL) was assessed before and after the intervention. Blood pressure was examined at the beginning and then hourly during the dialysis sessions. Dialysis efficacy, levels of phosphorus, calcium, sodium, potassium and Blood urea nitrogen (BUN) were measured at the end of the intervention. Kolmogorov-Smirnov test, paired t test, Wilcoxon signed rank and Friedman tests and repeated measure analysis of variancewere used to analyze the data. Results: No significant changes were observed in serum potassium, phosphorus and calcium levels at the end of the passive exercise program compared to the baseline. However, phosphorus levels were significantly decreased in the active exercise program (P < 0.05). Moreover, the mean diastolic blood pressure was significantly decreased after the passive exercise (P = 0.039). Passive exercise did not significantly change the dialysis efficacy, urea reduction rate, hemoglobin and calcium levels. The mean overall QOL was 63.78 ± 21.15 at the beginning of the study, which was increased to 77.07 ± 21.14 at the end of eight weeks of the intradialytic exercise (P = 0.007). Conclusions: The passive intradialytic exercise had a positive effect on blood pressure. The active exercise could decrease the serum phosphorus and potassium levels. Moreover, both exercise programs could significantly improve the QOL. Both active and passive intradialytic exercises can have some beneficial effects

    Micropalaeontological studies of recent sediments from the Cilicia Basin (N.E. Mediterranean)

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    Frequency and Predictors of Courses Repetition, Probation, and Delayed Graduation in Kashan Faculty of Nursing and Midwifery

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    Background: Course failing and delayed graduation are important concerns in educational systems. The reasons of these educational failures need to be clarified. Objectives: This study was designed to determine the academic failure rate and its predictors in Nursing and Midwifery Students in Kashan University of Medical Sciences. Materials and Methods: In this cross-sectional study, the records of all the students graduated in Nursing and Midwifery faculty during 18 years (1986 - 2003) were evaluated (1174 graduates). The demographic variables and the educational situation were recorded. The frequency of course repetition, probation, and delayed graduation were determined and the data were analyzed using the chi-square and logistic regression tests. Results: The frequency of course repetition, probation, and delayed graduation was reported to be 19.25%, 3.9% and 19.85%, respectively. Gaining Low grade in high school, transferring from other universities, having special quota, and transferring temporarily to other universities were mentioned as the risk factors of academic failure. The major had a significant relationship with academic failure. Day time students had more course failure and night time students stayed longer in the university. Conclusions: The individual characteristics, educational background and admission criteria had showed relation with academic failure. Vulnerable students should be identified and educational supports should be provided for these students

    Effect of Estradiol and Soy Extract on the Onset of PTZ-Induced Seizure in Ovariectomized Rats: Implications for Nurses and Midwives

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    Background: In many epileptic women, the ovarian cycle influences the risk and severity of seizures. Previous studies have reported inconsistent findings regarding the neural excitatory effects of estrogen. Soybean is a rich source of plant estrogens. Therefore, soy intake can affect the risk and severity of seizures in women. Nurses and midwives need to be aware of the effects of diets containing estrogen in pregnant and post-menopausal women, as well as during the sexual cycle periods. Objectives: Due to the limitations of human studies, this study aimed to investigate the effect of estradiol and soy extract on the onset of pentylenetetrazol (PTZ)-induced seizures in ovariectomized rats. Materials and Methods: In this experimental study, sixty female Wistar rats were randomly divided into six groups of ten. All of the groups except for the negative control groups were ovariectomized. One group received estradiol (100 µg/kg), one group was treated with alcoholic extract of soy (20 mg/kg), and the other group received vehicle over 28 days. PTZ (90 mg/kg) was used to induce seizure in all groups. Behavioral changes were observed over 30 minutes. All data were analyzed using a two-way analysis of variance with Tukey’s post-hoc test. Results: The mean ± SD of the clonic seizure threshold was 61.84 ± 8.53 in the group that received estradiol, while it was 71.70 ± 10.85 in the control group, 64.69 ± 3.23 in rats with laparotomy without removing the ovaries, 51.30 ± 6.84 in rats with laparotomy and removing the ovaries, 52.7 ± 7.18 in ovariectomized rats that received sesame oil as vehicle, and 59.2 ± 4.91, in the soy groups. Therefore, estradiol significantly increased the clonic seizure threshold, while the alcoholic extract of soy had no effect. Conclusions: We concluded that the chronic administration of estradiol has an anticonvulsant effect in the animal model. However, alcoholic extract of soy has no effect on the onset of clonic seizures

    Comparison of antibiotics and bacteriocins antibacterial activity on Xanthomonas citri subsp.citri

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    Citrus canker is a citrus disease species created by the bacterium Xanthomonas citri subsp.citri. Many citrus, such as oranges, lime, and grapefruit are affected by the infectious bacteria and stems, leaves and fruits are experiencing loss. In this experiment antibacterial effects of five kinds of antibiotics including ampicillin, kanamycin, chloramphenicol, penicillin, streptomycin, Cronobacteriocin DGH2 and Enterobacteriocin DGH4 were evaluated on 107 strains of Xanthomonas citri subsp.citri. MIC and MBC data for antibiotics and bacteriocins against Xanthomonas strains were performed. According to this project, Xanthomonas strains were comparatively susceptible and resistant to Cronobacteriocin DGH2, Enterobacteriocin DGH4, ampicillin, kanamycin, chloramphenicol, penicillin and streptomycin. NIGEB-183 strain is the most sensitive to these antibiotics and bacteriocins. However, only the NIGEB-242R1 strain is resistant to chloramphenicol. Penicillin has minimum inhibitory effects on Xanthomonas strains. Based on this case study, chloramphenicol is the most antibacterial activity among antibacterial agents and this compound is a good candidate for inhibitory activity. Cronobacteriocin DGH2 has a moderate antibacterial activity against Xanthomonas strains

    Perturbative Matching of the staggered four-fermion operators for e'/e

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    Using staggered fermions, we calculate the perturbative corrections to the bilinear and four-fermion operators that are used in the numerical study of weak matrix elements for ϵ/ϵ\epsilon'/\epsilon. We present results for one-loop matching coefficients between continuum operators, calculated in the Naive Dimensional Regularization (NDR) scheme, and gauge invariant staggered fermion operators. These results, combined with existing results for penguin diagrams, provide the complete one-loop renormalization of the staggered four-fermion operators.Comment: 36 pages. will appear in physical review

    Light hadron spectrum and quark masses in QCD with two flavors of dynamical quarks

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    We present updated results of the CP-PACS calculation of the light hadron spectrum in Nf=2N_{\rm f}=2 full QCD. Simulations are made with an RG-improved gauge action and a tadpole-improved clover quark action for sea quark masses corresponding to mPS/mV0.8m_{\rm PS}/m_{\rm V} \approx 0.8--0.6 and the lattice spacing a=0.22a=0.22--0.09 fm. A comparison of the full QCD spectrum with new quenched results, obtained with the same improved action, shows clearly the existence of sea quark effects in vector meson masses. Results for light quark masses in Nf=2N_{\rm f}=2 QCD are also presented.Comment: Latex 3 pages, 6 PostScript figures, Talk presented at LATTICE99(QCD Spectrum and Quark Masses
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