Influence Of Toroidal Effects On The Stability Of The Internal Kink Mode

Using the σ-stability technique, we study the stability of the internal kink mode in toroidal geometry. We show that there are two unstable regions separated by a stable one in a β-qc stability diagram. In one of these regions toroidal effects are stabilizing and in the other they are destabilizing. Discrepant results of previous analytical theories and experimental results are explained. © 1978 The American Physical Society.411387087

The effect of chirality on a plasma media

The theoretical properties of a composite chiral-plasma medium are developed. By using the reaction theorem, for a magnetized chiroplasma, we obtain the proof of nonreciprocity based upon the constitutive relationships between electromagnetic vectors (E) over right arrow, (B) over right arrow, (H) over right arrow, (D) over right arrow. Using the Maxwell's equations and the proposed constitutive relations for a chiral-plasma medium, we derive the vectors (E) over right arrow and (H) over right arrow equations and from these equations, dispersion relations and (E) over right arrow-field polarization are obtained. For circularly polarized waves, a new mode conversion is founded due to the chiral effect. For the lower branch of the extraordinary wave mode there is no more bands of forbidden frequencies and the reflection point vanishes when the chiral parameter increases.426989100

High frequency electromagnetic waves in a bounded, magnetized and warm plasma

A b s t r a c t The electromagnetic waves in a uniform, magnetized plasma, bounded by a cylindrical waveguide are studied using warm plasma theory. In the case of a cold plasma, backward electromagnetic waves are obtained which exhibit the phenomenon of Faraday rotation, in contrast to the Trivelpiece and Gould electrostatic modes which do not show this characteristic. Numerical results are presented for the linear LISA machine. A generalization of the Ghosh and Pal dispersion relation for a warm, magnetized plasma is derived

Probe measurements of plasma potential nonuniformity due to edge asymmetry in large-area radio-frequency reactors: the telegraph effect

In large-area radio-frequency (rf) capacitive reactors, the redistribution of rf current to maintain current continuity near asymmetric sidewalls causes a perturbation in rf plasma potential to propagate along the resistive plasma between capacitive sheaths. The damping length of the perturbation can be determined by a telegraph equation. Experiments are described using a surface array of unbiased electrostatic probes in the ground electrode to verify the theoretical model of the telegraph effect in Howling [J. Appl. Phys. 96, 5429 (2004)]. The measured spatial dependence of the plasma potential rf amplitude and circulating nonambipolar current agree well with two-dimensional numerical solutions of the telegraph equation. The rf plasma potential can be made uniform by using symmetric reactor sidewalls

Negative assimilation:how immigrants experience economic mobility in Japan

This paper examines the economic mobility of foreign migrants in Japan. In a country that is largely regarded as homogeneous and closed to outsiders, how and to what extent do immigrants achieve economic success? A survey conducted by the authors revealed that the conventional assimilationist perspective does not fully explain immigrants’ economic success in Japan. Migrants from the West experience what Chiswick and Miller (2011) refer to as “negative assimilation.” That is, their earnings decline over time in Japan. While negative assimilation was not clearly observed among immigrants from neighboring Asian countries, wages among them did not increase with the length of their stay in Japan. For both groups, the skills they brought from abroad were found to be largely accountable for their economic success, while locally specific human capital, such as education acquired in the host society, did not contribute to their earnings

Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse

Recombinant human erythropoietin increases survival and reduces neuronal apoptosis in a murine model of cerebral malaria

<p>Abstract</p> <p>Background</p> <p>Cerebral malaria (CM) is an acute encephalopathy with increased pro-inflammatory cytokines, sequestration of parasitized erythrocytes and localized ischaemia. In children CM induces cognitive impairment in about 10% of the survivors. Erythropoietin (Epo) has – besides of its well known haematopoietic properties – significant anti-inflammatory, antioxidant and anti-apoptotic effects in various brain disorders. The neurobiological responses to exogenously injected Epo during murine CM were examined.</p> <p>Methods</p> <p>Female C57BL/6j mice (4–6 weeks), infected with <it>Plasmodium berghei </it>ANKA, were treated with recombinant human Epo (rhEpo; 50–5000 U/kg/OD, i.p.) at different time points. The effect on survival was measured. Brain pathology was investigated by TUNEL (Terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-digoxigenin nick end labelling), as a marker of apoptosis. Gene expression in brain tissue was measured by real time PCR.</p> <p>Results</p> <p>Treatment with rhEpo increased survival in mice with CM in a dose- and time-dependent manner and reduced apoptotic cell death of neurons as well as the expression of pro-inflammatory cytokines in the brain. This neuroprotective effect appeared to be independent of the haematopoietic effect.</p> <p>Conclusion</p> <p>These results and its excellent safety profile in humans makes rhEpo a potential candidate for adjunct treatment of CM.</p