Confinement of plasma along shaped open magnetic fields from the centrifugal force of supersonic plasma rotation.

Interferometric density measurements in plasmas rotating in shaped, open magnetic fields demonstrate strong confinement of plasma parallel to the magnetic field, with density drops of more than a factor of 10. Taken together with spectroscopic measurements of supersonic E × B rotation of sonic Mach 2, these measurements are in agreement with ideal MHD theory which predicts large parallel pressure drops balanced by centrifugal forces in supersonically rotating plasmas.

Epitaxy and magnetic properties of surfactant-mediated growth of bcc cobalt.

High resolution core level photoemission spectroscopy, photoelectron diffraction, and x-ray magnetic circular dicroism (XMCD) have been used to characterize the structural and magnetic properties of bcc-cobalt films grown on GaAs(110) substrates by using Sb as a surfactant. We have unambiguously disentangled the surfactant role played by the Sb which improves the crystallinity and reduces the lattice distortion of the metallic films as well as changes the interdiffusion process at the interface compared to the Co/GaAs(110) system. As a consequence of these combined effects, an improvement on the magnetic response of the grown Co thin films has been observed by XMCD measurements.

A gas microstrip detector for XAS studies in the photon energy region 300-1500 eV.

The ability to perform X-ray absorption spectroscopy (XAS) in the 300-1500 eV energy range allows measurements to be made on transition metal compounds. This paper describes a detector and the technique used to perform fluorescent measurements on such materials. A variety of test sample results are shown to illustrate the low energy and energy-resolving capabilities of the detector (based on gas microstrip technology). Two possible applications are also demonstrated. The first shows how the detector can be used to gather X-ray absorption spectra for the L edges of transition metals and K edges of light elements (C, O and N). The other shows how the magnetic immunity of the detector can be exploited to study the magnetic properties of materials.

Observation of inverse ion-cyclotron damping induced by parallel-velocity shear.

The generation of broadband multiharmonic spectra of electrostatic ion-cyclotron waves is demonstrated in a magnetized laboratory plasma in which shear in the magnetic-field-aligned (parallel) ion flow and a relative parallel electron drift are present. Shear correlates with an increased number of harmonics and a decreased electron drift speed. Wave and particle measurements indicate that cyclotron damping is reduced and even becomes negative. The fluctuations in the time domain are spiky, similar to electric-field fluctuations observed both in Earth's auroral zone and in numerical simulations.

Experimental verification of the shear-modified ion-acoustic instability.

The predicted shear-induced shift of the wave phase velocity, the essence of the shear-modified ion-acoustic (SMIA) instability mechanism that reduces ion Landau damping for otherwise damped ion-acoustic waves [V. Gavrishchaka et al., 80, 728 (1998)], is verified with direct measurements in a strongly magnetized laboratory plasma. The SMIA growth rate is shown to increase with increasing shear, as predicted. SMIA wave propagation is shown to be possible at both small and large angles to the magnetic field, consistent with space observations of ion-acoustic-like waves.

Ferromagnetic hcp chromium in Cr/Ru(0001) superlattices.

We report the first observation of a weak ferromagnetic state of Cr in Cr/Ru(0001) superlattices, based on magnetic hysteresis and corroborated by x-ray magnetic circular dichroism at the CrL(2,3) edges. In situ reflection high-energy electron diffraction, x-ray diffraction, and Cr K-edge polarized x-ray absorption investigations have shown that the Cr layers thinner than 8 angstroms adopt a slightly distorted hcp structure, accompanied by a large atomic volume expansion of up to 14% compared to the bcc packing volume. The expanded hcp structure clearly induces the observed ferromagnetism, in agreement with theory.

Accelerated streptokinase--a new thrombolytic regimen in acute myocardial infarction.

Efficiency and safety of an accelerated regimen of streptokinase (1.5 M.U. over 20 min., 109 patients) has been compared with the standard regimen (1.5 M.U. over 60 min, 119 patients) in 218 patients admitted within the first 6 hours after the onset of the symptoms of acute myocardial infarction. Using the noninvasive criteria we found a coronary reperfusion rate of 77.04% in patients belonging to the accelerated regimen group and this value was significantly higher than the one of 57.14% registered in the standard group. No major hemorrhagic events were registered in both groups. Although the hypotension appeared to be more frequent in patients in whom the accelerated regimen was used, however this side effect proved to be transient and well controlled using the rapid infusion of natrium chloride solution. In conclusion, the accelerated regimen of streptokinase is safe and followed by a higher rate of coronary reperfusion as compared to the standard one.

Rapid infusion of streptokinase standard dose in acute myocardial infarction is followed by a higher rate of coronary reperfusion than standard protocol.

There are several opinions asserting that the accelerated t-PA is more efficient than the standard protocol of streptokinase (SK) administration in acute myocardial infarction (AMI). One hundred patients admitted within the first 6 hrs after the onset of the symptoms revealing AMI were divided in two subgroups, as follows: subgroup A (50 patients) in whom a dose of 1.5 M.U. SK was infused in 20 min (accelerated protocol) and subgroup B (50 patients) in whom the same dose was infused in 60 min (standard protocol). In order to assess the efficiency of thrombolytic therapy (TT), we used three noninvasive criteria: the rapid resolution of the chest pain, the rapid decreasing of the ST segment elevation by more than 50% from the initial value, and the rapid increasing of enzymes revealing necrosis. Using the above-mentioned criteria, we considered that coronary reperfusion appeared in 40 patients from subgroup A (80%) and in 29 patients from subgroup B (58%). The speed of coronary reperfusion was 40 +/- 26 min in patients with accelerated SK and this time was significantly shorter than the time of 60 +/- 24 min registered in the control group. No major hemorrhagic events appeared in both subgroups. Although hypotension appeared more frequently in subgroup A, this minor complication was well supported by our patients. The rapid infusion of the standard dose of SK was followed by a higher rate and speed of coronary reperfusion as compared to the standard protocol.

Techniques for evidencing the respiratory patterns and their temporal shift.

To enhance the efficiency of de visu or automatic detection and analysis of of the respiratory patterns, new techniques are introduced to process the respiratory signals. These techniques include: the dynamical frequency analysis, spectral envelope detection, three-dimensional representation of the spectral envelopes, and the 'respirogram'.

Frequency analysis of the acoustical respiratory response.

The frequency-domain analysis of respiration is used to put in evidence the respiratory reflexes, mainly the acoustical respiratory reflex. Based on the envelope of the spectrum, numerical parameters of the respiration are introduced and applied to determine respiratory patterns. The use of respirograms is also suggested.

[The importance of some factors which endanger the eradication of malaria in Moldavia]. / Ponderea unor factori care pericliteaza eradicarea paludismului în Moldova.

The present paper reports on the results of a haematologic and serologic survey carried out for assessing quantitatively and qualitatively the importation of malaria, in terms of the two routes of penetration of plasmodia in Moldavia. Examination of peripheral blood droplets and testing by indirect immunofluorescence showed the higher proportions recorded in subjects coming from endemic malarial areas (6.6% and 70.9% respectively) than in our citizens travelling abroad in malarial areas (0.1% and 3.3% respectively). Attention is drawn to the essential components of the epidemiologic situation today: the existence of a dynamic reservoir of import plasmodia that can only be partly detected and is added to the residual autochtonous reservoir of P. malariae, to the receptivity of the human population and the presence of the natural transmitter vector P. vivax.