Polarized synchrotron emission and absorption coefficients for thermal, nonthermal, and kappa electron distributions

Astrophysical plasmas play a role in many of the most interesting systems in the universe they swirl around black holes at tremendous speeds, compose the solar wind, and even produce auroras in planetary magnetospheres. All of these plasmas emit light via the process of synchrotron radiation, which results when relativistic electrons orbit around magnetic field lines. For this project, I have written a novel code named symphony to calculate polarized emission and absorption coefficients for a plasma with a general gyrotropic electron energy distribution. This code was used to study three electron distributions in particular: a relativistic thermal (Maxwell- Jttner) distribution, a nonthermal power law distribution, and the so-called kappa distribution, which has thermal behavior at low energy and power law behavior at high energy. The kappa distribution merits attention because it fits many of the observed properties of well-studied space plasmas, such as the solar wind. Using symphony we also produced approximate fitting formulae to the polarized emission and absorption coefficients for the three distributions studied. These fitting formulae may be of use to those involved in modeling astrophysical plasmas because these simulations are often constrained by computation time, and the fitting formulae allow for rapid evaluation of synchrotron emission and absorption.NSF grant AST-1333612Ope

ક્ષાર પ્રસારણ અને તેની કૃષિક્ષેત્ર પર અસરઃ સૌરાષ્ટ્રના દરિયા કાંઠાના વિસ્તાર પરનો અભ્યાસ

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Quantm Magnetoresistance of the PrFeAsO oxypnictides

We report the observation of an unusual $B$ dependence of transverse magnetoresistance (MR) in the PrFeAsO, one of the parent compound of pnictide superconductors. Below the spin density wave transition, MR is large, positive and increases with decreasing temperature. At low temperatures, MR increases linearly with $B$ up to 14 T. For $T$$\geq$40 K, MR vs $B$ curve develops a weak curvature in the low-field region which indicates a crossover from $B$ linear to $B^2$ dependence as $B$$\rightarrow$0. The $B$ linear MR originates from the Dirac cone states and has been explained by the quantum mechanical model proposed by Abrikosov.Comment: accepted for publication in Appl. Phys. Let

Development of an empirically based dynamic biomechanical strength model

The focus here is on the development of a dynamic strength model for humans. Our model is based on empirical data. The shoulder, elbow, and wrist joints are characterized in terms of maximum isolated torque, position, and velocity in all rotational planes. This information is reduced by a least squares regression technique into a table of single variable second degree polynomial equations determining the torque as a function of position and velocity. The isolated joint torque equations are then used to compute forces resulting from a composite motion, which in this case is a ratchet wrench push and pull operation. What is presented here is a comparison of the computed or predicted results of the model with the actual measured values for the composite motion

A Comparative Analysis of Liquidity & Profitability of Indian Car Industry

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A Rare Entity: Case Report of Recurrent Hypertrophic Pyloric Stenosis

Introduction: Hypertrophic pyloric stenosis (HPS) is well known in pediatric surgery and has good outcomes after pyloromyotomy.1 Emesis in the immediate postoperative period occurs in 40% of patients with HPS and is attributed to gastroparesis from prolonged gastric distention.2 Emesis presenting weeks to months after pyloromyotomy prompts an evaluation that often yields pathology unrelated to HPS. Because recurrent HPS is rare, making this diagnosis highlighted the importance of practicing broad differential diagnoses, ruling out most common causes, and including obscure etiologies. Clinical Findings: A 3-week-old male born after full-term gestation with a history of HPS underwent an uncomplicated laparoscopic pyloromyotomy. He had an uneventful initial recovery but then presented with recurrent projectile nonbilious emesis 7 weeks postoperatively. Between presentations, the patient consistently tolerated feeds and gained weight. Informed consent was obtained. Clinical Course: The patient was evaluated with an abdominal ultrasound, which revealed a hypertrophic pyloric channel, and an upper gastrointestinal contrast (UGI) study, which showed a partial gastric outlet obstruction. He underwent laparoscopy, which revealed a thickened pyloric channel, prompting a repeat pyloromyotomy. Postoperatively, his diet was advanced, and he was discharged on postoperative day 1. Conclusions: Emesis after pyloromyotomy for HPS is common and usually self-limited. Recurrent emesis after normal feeding for weeks or months often yields a diagnosis unrelated to HPS. However, if other more common causes of emesis are excluded, then recurrent HPS can be evaluated with abdominal ultrasound and an UGI study. Once diagnosed, laparoscopic repeat pyloromyotomy is an appropriate treatment option