Quantum oscillations of resistivity in bismuth nanowires

We studied the influence of uniaxial deformation on the transport properties of bismuth wires in the wide range of temperatures. Measurements of the resistance of bismuth nanowires with several diameters and different quality reveal oscillations on the dependence of resistance under uniaxial strain at T = 4.2 K. Amplitude of oscillations is significant (38%) at helium temperature and becomes smearing at T = 77 K. Observed oscillations originate from quantum size effect. Evaluation of period of oscillations allows us to identify the groups of carriers involved in transport. Calculated periods of 42.2 and 25.9 nm satisfy approximatively the ratio 2:1 for two experimentally observed sets of oscillations from light and heavy electrons

Spontaneous intracerebral supratentorial hemorrhage: general aspects and updates in surgical treatment

Laboratory of Neurosurgery Anesthesia and Reanimation, Institute of Neurology and Neurosurgery, Department of Neurology, Institute of Emergency Medicine, Department of Radiology and Medical Imaging, Nicolae Testemitsanu State University of Medicine and Pharmacy, Chisinau, the Republic of MoldovaBackground: Spontaneous intracerebral hemorrhage (SIH) accounts for 9 to 25% of all strokes and is associated with a high morbidity and mortality, with less than 40% of affected persons surviving 1 year. The condition commonly presents a sudden onset of focal neurological deficits with accompanying headache, nausea, vomiting, elevated blood pressure and altered consciousness. Medical treatment commonly includes airway support, blood pressure control, management of cerebral edema, symptomatic therapy such as anticonvulsive medication, anticoagulation reversal etc. Different surgical options such as open craniotomy, stereotactic aspiration, endoscopic evacuations with or without thrombolysis have also been considered. Most of these techniques have already been implemented successfully in the Republic of Moldova. According to the data of the Institute of Neurology and Neurosurgery and the Institute of Emergency Medicine for the period 2011-2014, just within these two institutions were performed 137 neurosurgical interventions, including 67 interventions involving minimally invasive techniques with local fibrilolysis and 70 interventions involving other minimally invasive surgery or conventional craniotomy. The obtained results are in concordance with those reported by other European institutions. Conclusions: The continuous efforts to improve the outcome of SIH during the recent years have led to the development of a variety of minimally invasive techniques, most of which have already been adopted by the autochthonous surgeons. New randomized controlled trials are required to establish the suitability of these techniques for different clinical situations and SIH localizations

Variation and evolution of toxin gene expression patterns of six closely related venomous marine snails

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75661/1/j.1365-294X.2008.03804.x.pd

Possible mechanism responsible for observed impurity outward flow under radio frequency heating

The effect of poloidal asymmetry of impurities on impurity transport driven by electrostatic turbulence in tokamak plasmas is analyzed. It is found that in the presence of in-out asymmetric impurity populations the zero-flux impurity density gradient (the so-called peaking factor) is significantly reduced. A sign change in the impurity flux may occur if the asymmetry is sufficiently large. This may be a contributing reason for the observed outward convection of impurities in the presence of radio frequency heating. The effect of in-out asymmetry is most significant in regions with low temperature gradients. In the trapped electron mode dominated case also an up-down asymmetry can lead to a sign change in the peaking factor from positive to negative. The effect of ion parallel compressibility on the peaking factor is significant, and leads to positive peaking factors in regions with high temperature gradients, even in the presence of in-out asymmetry.Comment: 19 pages, 14 figure

Recent results from the electron cyclotron heated plasmas in Tokamak à Configuration Variable (TCV)

In noninductively driven discharges, 0.9 MW second harmonic (X2) off-axis co-electron cyclotron current drive deposition is combined with 0.45 MW X2 central heating to create an electron internal transport barrier (eITB) in steady plasma conditions resulting in a 1.6-fold increase of the confinement time (tau(Ee)) over ITER-98L-mode scaling. The eITB is associated with a reversed shear current profile enhanced by a large bootstrap current fraction (up to 80%) and is sustained for up to 10 current redistribution times. A linear dependence of the confinement improvement on the product of the global shear reversal factor (q(0)/q(min)) and the reversed shear volume (rho(q-min)(2)) is shown. In other discharges heated with X2 the sawteeth are destabilized (respectively stabilized) when heating just inside (respectively outside) the q=1 surface. Control of the sawteeth may allow the avoidance of neoclassical tearing modes that can be seeded by the sawtooth instability. Results on H-mode and highly elongated plasmas using the newly completed third harmonic (X3) system and achieving up to 100% absorption are also discussed, along with comparison of experimental results with the TORAY-GA ray tracing code [K. Matsuda, IEEE Trans. Plasma Sci. PS-17, 6 (1989); R. H. Cohen, Phys. Fluids 30, 2442 (1987)]. (C) 2003 American Institute of Physics