Propagation of ion-acoustic solitary waves in a warm plasma with negative ions under the drifting effect of electrons is considered. Compressive and rarefactive solitons are shown to exist depending on the drift velocity v′e of electrons for different values of Q′ (mj/mi—negative to positive ion mass ratio) ≥1 or ≤1. The amplitude of the compressive soliton for Q′≥1 and rarefactive soliton for Q′≤1 but small, is found to be greatest near v′e = 0 when r (=nj0/ni0, negative to positive ion number density ratio) ≤0.5, showing thereby the characteristic change in solitons for the inclusion of v′e.
A two fluid model has been employed to study the oblique propagation of solitary kinetic Alfvén waves. Formation of solitary waves and double layers is observed. Amplitude, width (in the case of solitons), and thickness (in the case of double layers) of the nonlinear structures are studied in some detail. Wider solitary structures are found to exist for oblique propagation nearer to the magnetic field direction.
Introduction: Leptin is an adipocyte derived hormone encoded by ob gene which serves as a relay link between metabolic signals and brain that regulate the hypothalamic pituitary ovarian axis. Leptin is related with obesity which is a most important cause of Polycystic Ovarian Syndrome (PCOS) in women of reproductive age group. Aim: To evaluate leptin concentration and to analyse its correlation with Body Mass Index (BMI) and insulin resistance in PCOS. Materials and Methods: This case-control study was conducted from December 2018 to December 2019 at Department of Biochemistry in collaboration with Department of Obstetrics and Gynaecology, MKCG Medical College and Hospital, Berhampur, Odisha, India. A total of 60 PCOS subjects, aged between 15-30 years (30 obese PCOS and 30 lean PCOS) and 30 age matched, normal ovulatory healthy controls were included in the study. Parameters such as serum leptin, fasting plasma insulin, Homeostatic Model Assessment-Insulin Resistance (HOMA-IR), Fasting Plasma Glucose (PPG), Postprandial Plasma Glucose (PPPG) were estimated using commercial kits. One-way Analysis of Variance (ANOVA) test was used for data analysis and the Pearson’s correlation method was used to find the correlation between the parameters. Results: The mean age of women in all the three PCOS groups was found to be 22.4±3.13 years. The BMI of obese PCOS patients (31.9±4.7 kg/m2 ) and lean PCOS patients (21.4±2.2 kg/m2 ) were higher than that of healthy controls (20.7±1.8 kg/m2 ) which was statistically significant (p-value <0.001). The serum leptin in obese PCOS were significantly higher (28.0±17.8 ng/mL) than lean PCOS (5.8±2.2 ng/mL) and fasting plasma insulin in lean PCOS were (10.9±2.4 µIU/mL) significantly lower than obese PCOS (30.2±14.8 µIU/mL). Mean serum leptin levels had significant positive correlation with BMI in lean and obese PCOS and insulin resistance in obese PCOS. Conclusion: In the present study, high leptin concentration was observed in PCOS patients and there was positive correlation of leptin with BMI in both lean and obese PCOS groups and leptin was positively correlated with insulin resistance in obese PCOS.
Large amplitude electrostatic structures associated with low-frequency dust kinetic Alfvénic waves are investigated under the pressure (temperature) gradient indicative of dust dynamics. The set of equations governing the dust dynamics, Boltzmann electrons, ions and Maxwell’s equation have been reduced to a single equation known as the Sagdeev potential equation. Parameter ranges for the existence of arbitrary amplitude double layers are observed. Exact analytical expressions for the energy integral is obtained and computed numerically through which sub-Alfvénic arbitrary amplitude rarefactive double layers are found to exist.
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