604 research outputs found

    Charged Particles Circular Orbits around Weakly Charged and Magnetized Kerr Black Holes

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    We study the circular orbits of charged particles around a weakly charged Kerr black hole immersed in a weak, axisymmetric magnetic field. Firstly, we review the circular orbits of neutral particles. We then review the circular orbits of charged particles around a weakly charged Kerr black hole and weakly magnetized Kerr black hole. The case of a weakly magnetized and charged black hole is investigated thereafter. We investigate, in particular, the effect of the electromagnetic forces on the charged particles' innermost stable circular orbits. We examine the conditions for the existence of negative-energy stable circular orbits and the possibility of the emergence of a gap or double orbit in thin accretion disks. Some of the interesting astrophysical consequences of our findings are discussed as well.Comment: Accepted for publication in the Astrophysical Journal. arXiv admin note: substantial text overlap with arXiv:2208.1395

    Pelvic Lymphadenectomy in the Treatment of Invasive Bladder Cancer: Literature Review

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    The standard surgical treatment of invasive bladder cancer is the radical cystectomy and pelvic lymph node dissection (PLND). Up to one-third of patients with invasive bladder cancer have lymph node metastasis. Thus, PLND has important therapeutic and prognostic benefits. The number of lymph nodes that should be removed and the extent of the PLND are still a controversial issue. Recently, the trend of PLND increased toward more extended PLND. Several prognostic factors related to PLND were reported in the literature. In this paper, we will discuss the different PLND templates, number of lymph nodes that should be resected, lymph node density, lymphovascular invasion, tumor burden, extracapsular extension, and the aggregate lymph node metastasis diameter

    The impacts of substance abuse and dependence on neuropsychological functions in a sample of patients from Saudi Arabia

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    <p>Abstract</p> <p>Background</p> <p>A lot of studies were directed to explore the relation between drug abuse and neuropsychological functions. Some studies reported that even after a long duration of disappearance of withdrawal or intoxication symptoms, many patients have obvious deterioration of cognitive functions. The aim of this study was to explore the relationship between the substance use disorders and the executive functions.</p> <p>Methods</p> <p>Two groups were selected for this study. An experimental group consisted of 154 patients and further subdivided according to the substance used into three different subgroups: opioid, amphetamine and alcohol groups which included 49, 56 and 49 patients respectively. The control group was selected matching the experimental group in the demographic characteristics and included 100 healthy persons. Tools used were: Benton visual retention tests, color trail making test, Stroop colors-word test, symbol digit modalities test, the five dots cognitive flexibility test, and TAM verbal flexibility test. All the data were subjected to statistical analysis</p> <p>Results</p> <p>The study showed that the group of drug-dependent subjects performed significantly worse than the comparison group on all measures Also, there were significant differences among the subgroups as the alcoholic group was much worse followed by the amphetamine then the opioids groups. Patients with longer duration of dependence and multiple hospital readmissions were much worse in comparison to patients with shorter duration of dependence and less readmission.</p> <p>Conclusion</p> <p>The study confirmed that the functions of specific brain regions underlying cognitive control are significantly impaired in patients of drug addiction. This impairment was significantly related to type of substance, duration of use and number of hospitalization and may contribute to most of behavioral disturbances found in addicts and need much attention during tailoring of treatment programs.</p

    Particle Dynamics in Weakly Charged Extreme Kerr Throat

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    We study dynamics of a test charged particle moving in a weakly charged extreme Kerr throat. Dynamical equations of the particle motion are solved in quadratures. We show explicitly that the Killing tensor of the Kerr spacetime becomes reducible in the extreme Kerr throat geometry. Special types of motion of particles and light are discussed.Comment: The paper is prepared for the fest volume devoted to 75th Birthday of Mario Castagnin

    Diffuse Large B-Cell Lymphoma Transformed from Mucosa-Associated Lymphoid Tissue Lymphoma Arising in a Female Urethra Treated with Rituximab for the First Time

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    A 30-year-old female patient presented to the gynecology clinic with a small (painless) swelling at the urethral orifice. She underwent surgical excision of the lesion. Pathological examination revealed non-Hodgkin's lymphoma of diffuse large B-cell type and mucosa-associated lymphoid tissue type, stage IE. The patient refused radiotherapy. Accordingly, we started CHOP-R chemotherapy. She received a total of 6 cycles of CHOP and 8 cycles of rituximab. Patient follow-up was done 3 months later through CT scan and cytoscopy confirming the complete remission. The patient has been disease-free for 4 years. We reviewed 26 cases of this rare entity reported previously

    The Poisson-Lomax Distribution

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    In this paper we propose a new three-parameter lifetime distribution with upside-down bathtub shaped failure rate. The distribution is a compound distribution of the zero-truncated Poisson and the Lomax distributions (PLD). The density function, shape of the hazard rate function, a general expansion for moments, the density of the rth order statistic, and the mean and median deviations of the PLD are derived and studied in detail. The maximum likelihood estimators of the unknown parameters are obtained. The asymptotic confidence intervals for the parameters are also obtained based on asymptotic variance-covariance matrix. Finally, a real data set is analyzed to show the potential of the new proposed distribution
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