Dynamics of laser-bumped electron–hole semiconductor plasma

Electron–hole pairs in semiconductors can be stimulated by a laser beam with energy larger than the energy gap of the semiconductor. The interaction between an electron–hole plasma with a laser beam can be a source of instability. The dependence of the instability on the electron and hole temperatures and the unperturbed potential of the incident laser are examined. Using Maxwell’s equations along with electron–hole fluid equations, an evolution equation describing the system is obtained. The latter is reduced to an energy equation that characterizes localized pulse propagation

Conversion of fused knee following distal femur tumor surgery to total knee arthroplasty

Conversion of knee arthrodesis to total knee arthroplasty is a difficult procedure accompanied by many complications due to soft tissue and extensor mechanism contracture and bone defects. We report two cases of distal femur osteosarcoma that had been undergone wide resection arthrodesis initially. Arthrodesis was converted to total knee arthroplasty with hinged prosthesis after many years. We describe patients' history and outline their surgical therapy and prognosis. To the best of the authors' knowledge, few cases have been previously reported in the literature. © 2013, Iranian Red Crescent Medical Journal

Anisotropic Inflation from Charged Scalar Fields

We consider models of inflation with U(1) gauge fields and charged scalar fields including symmetry breaking potential, chaotic inflation and hybrid inflation. We show that there exist attractor solutions where the anisotropies produced during inflation becomes comparable to the slow-roll parameters. In the models where the inflaton field is a charged scalar field the gauge field becomes highly oscillatory at the end of inflation ending inflation quickly. Furthermore, in charged hybrid inflation the onset of waterfall phase transition at the end of inflation is affected significantly by the evolution of the background gauge field. Rapid oscillations of the gauge field and its coupling to inflaton can have interesting effects on preheating and non-Gaussianities.Comment: minor changes, references added, figures are modified, conforms JCAP published versio

Interpretation of localized surface nano-structures

Recent experiment was done to create surface nano-structures by extrusion of slow highly charged ions with LiNbO_3 single crystal. In this paper, we suggest a mechanism based on plasma expansion approach to explain the formation of the surface nano-structures. Furthermore, the effects of the physical parameters of the non-Maxwellian plasma on the created structures are examined

Neuropsychological function in relation to dysmenorrhea in adolescents

Objective: Hormonal variations during the menstrual cycle may affect emotional regulation. We aimed to investigate the association between dysmenorrhea (the severe abdominal pain and cramps associated with menstruation) and cognitive abilities, emotional function and sleep patterns in adolescent girls. Moreover, we evaluated the frequency of premenstrual syndrome (PMS) in our population and then divided them into 4 groups: subjects with only PMS; subjects with only dysmenorrhea; individuals with both PMS and dysmenorrhea and normal subjects. Study design: In this cross sectional study, 897 adolescent girls who had entered menarche were recruited. Of these, 35.9% had only dysmenorrhea, 14.9% had only PMS, 32.7% had both PMS and dysmenorrhea while 16.5% had no PMS and/or dysmenorrhea (Normal). We assessed the tests for cognitive, emotional function and sleep patterns were compared for these groups. Results: Individuals in the dysmenorrhea group had significantly higher depression, aggression, insomnia, daytime sleepiness and sleep apnea scores compared to normal controls and the PMS group, but did not have significantly different cognitive ability (P value < 0.05). These differences were strongly correlated to pain intensity (P < 0.001). However, there were no significant differences between those with only PMS and control subjects with regard to cognitive ability, emotional function and sleep pattern tests. Conclusions: Dysmenorrhea is highly prevalent among adolescents and appears to be associated with depressive mood, a tendency to aggressive behavior and sleep disorders among adolescent girls. (C) 2017 Elsevier B.V. All rights reserved

Two kinds of rogue waves of the general nonlinear Schr\"odinger equation with derivative

In this letter,the designable integrability(DI) of the variable coefficient derivative nonlinear Schr\"odinger equation (VCDNLSE) is shown by construction of an explicit transformation which maps VCDNLSE to the usual derivative nonlinear Schr\"odinger equation(DNLSE). One novel feature of VCDNLSE with DI is that its coefficients can be designed artificially and analytically by using transformation. What is more, from the rogue wave and rational traveling solution of the DNLSE, we get two kinds of rogue waves of the VCDNLSE by this transformation. One kind of rogue wave has vanishing boundary condition, and the other non-vanishing boundary condition. The DI of the VCDNLSE also provides a possible way to control the profile of the rogue wave in physical experiments.Comment: 8 pages, 5 figure

Diminishing benefits of urban living for children and adolescents’ growth and development

Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income&nbsp;countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was &lt;1.1 kg m–2 in the vast majority of&nbsp;countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified