SECONDARY RAYNAUD PHENOMENON IN WORKERS EXPOSED TO LOCAL VIBRATIONS

Forty-one workers (28 males and 13 females) with secondary Raynaud phenomenon were studied.  They were divided into two groups: group one - 28 workers exposed to vibrations and group two - 13 workers with overstrain and microtraumatism. The professional route, electroneurography, vegeto-vascular state, cryoglobulins, and erythrocytic antibodies were followed-up. The clinical diagnosis of vibration disease was proved in 24 workers (or 58,5 per cent of the cases). Immunohematologically, erythrocytic antibodies were found out in 13 of these patients. The relationship between the high percentage of erythrocytic antibodies and the secondary Raynaud phenomenon with the workers exposed to local vibrations was discussed

Progressor: Social navigation support through open social student modeling

The increased volumes of online learning content have produced two problems: how to help students to find the most appropriate resources and how to engage them in using these resources. Personalized and social learning have been suggested as potential ways to address these problems. Our work presented in this paper combines the ideas of personalized and social learning in the context of educational hypermedia. We introduce Progressor, an innovative Web-based tool based on the concepts of social navigation and open student modeling that helps students to find the most relevant resources in a large collection of parameterized self-assessment questions on Java programming. We have evaluated Progressor in a semester-long classroom study, the results of which are presented in this paper. The study confirmed the impact of personalized social navigation support provided by the system in the target context. The interface encouraged students to explore more topics attempting more questions and achieving higher success rates in answering them. A deeper analysis of the social navigation support mechanism revealed that the top students successfully led the way to discovering most relevant resources by creating clear pathways for weaker students. © 2013 Taylor and Francis Group, LLC

Phase diagram of a surface superconductor in parallel magnetic field

Detailed theory of phase diagram of clean 2D surface superconductor in a parallel magnetic field is presented. Regular spin-orbital interaction of the Rashba type is known to produce inhomogeneous superconductive state similar to the Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) state with $\Delta({\bf r})\propto \cos({\bf Qr})$ at high magnetic fields, with $Q \sim g\mu_B h/v_F$. We consider the case of relatively strong Rashba interaction and show that at low temperatures $T\leq 0.4 T_{c0}$ the LOFF-type state is separated from the usual homogeneous state by the first-order phase transition line. At higher temperatures new "helical" state with $\Delta({\bf r}) \propto \exp(i{\bf Qr})$ intervene between uniform BCS state and LOFF-like state. One component of superfluid density tensor $n_s$ vanishes on the second-order transition line between BCS state and helical state. Nonmagnetic impurities suppresses both inhomogeneous states, and eliminate them completely at $T_{c0}\tau \leq 0.11$.Comment: 5 pages, 1 figure; v2: as published, minor correction

Eccentric Contraction-Induced Muscle Fibre Adaptation

Hard-strength training induces strength increasing and muscle damage, especially after eccentric contractions. Eccentric contractions also lead to muscle adaptation. Symptoms of damage after repeated bout of the same or similar eccentrically biased exercises are markedly reduced. The mechanism of this repeated bout effect is unknown. Since electromyographic (EMG) power spectra scale to lower frequencies, the adaptation is related to neural adaptation of the central nervous system (CNS) presuming activation of slow-non-fatigable motor units or synchronization of motor unit firing. However, the repeated bout effect is also observed under repeated stimulation, i.e. without participation of the CNS. The aim of this study was to compare the possible effects of changes in intracellular action potential shape and in synchronization of motor units firing on EMG power spectra. To estimate possible degree of the effects of central and peripheral changes, interferent EMG was simulated under different intracellular action potential shapes and different degrees of synchronization of motor unit firing. It was shown that the effect of changes in intracellular action potential shape and muscle fibre propagation velocity (i.e. peripheral factors) on spectral characteristics of EMG signals could be stronger than the effect of synchronization of firing of different motor units (i.e. central factors)

THERAPEUTIC EFFECT OF COMPLEX PHYSICAL FACTORS IN DISEASES OF THE EXTREMITIES DUE TO OVERSTRAIN AND MICROTRAUMATISM

The authors treated with drugs and complex physical therapy 65 patients with occupational diseases of the extremities. According to the physiotherapeutic procedures, the patients were divided into five groups: 1s t - treated with galvanic baths; 2 n d - with galvanic baths and diadynamic current; 3 r d - with galvanic baths and short-wave therapy; 4t h - with galvanic baths and paraffin, and 5t h - with galvanic baths and high-voltage, low-frequency current. Patient's improvement was evaluated according to the reduction of subjective complaints such as shivering and pain as well as to a series of objective parameters such as muscle strength, skin temperature, time for skin temperature restoration, and peripheral blood flow. The subjective complaints were better influenced than the objective indices. The combination of galvanic baths with short-wave therapy exerted the best effect in the patients with occupational diseases of the extremities

Theory of 2D superconductor with broken inversion symmetry

A detailed theory of a phase diagram of a 2D surface superconductor in a parallel magnetic field is presented. A spin-orbital interaction of the Rashba type is known to produce at a high magnetic field $h$ (and in the absence of impurities) an inhomogeneous superconductive phase similar to the Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) state with an order parameter $\Delta(r) \propto \cos(Qr)$. We consider the case of a strong Rashba interaction with the spin-orbital splitting much larger than the superconductive gap $\Delta$, and show that at low temperatures $T\leq 0.4 T_{c0}$ the LOFF-type state is separated from the usual homogeneous state by a first-order phase transition line. At higher temperatures another inhomogeneous state with $\Delta(r) \propto \exp(i Qr)$ intervenes between the uniform BCS state and the LOFF-like state at $g\mu_B h \approx 1.5 T_{c0}$. The modulation vector $Q$ in both phases is of the order of $g\mu_B h/v_F$. The superfluid density $n_s^{yy}$ vanishes in the region around the second-order transition line between the BCS state and the new ``helical'' state. Non-magnetic impurities suppress both inhomogeneous states, and eliminate them completely at $T_{c0}\tau \leq 0.11$. However, once an account is made of the next-order term over the small parameter $\alpha/v_F \ll 1$, a relatively long-wave helical modulation with $Q \sim g\mu_B h\alpha/v_F^2$ is found to develop from the BCS state. This long-wave modulation is stable with respect to disorder. In addition, we predict that unusual vortex defects with a continuous core exist near the phase boundary between the helical and the LOFF-like states. In particular, in the LOFF-like state these defects may carry a half-integer flux.Comment: 23 pages, 14 figure

Magnetic properties of superconductors with strong spin-orbit coupling

We study the response of a superconductor with a strong spin-orbit coupling on an external magnetic field. The Ginzburg-Landau free energy functional is derived microscopically for a general crystal structure, both with and without an inversion center, and for an arbitrary symmetry of the superconducting order parameter. As a by-product, we obtain the general expressions for the intrinsic magnetic moment of the Cooper pairs. It is shown that the Ginzburg-Landau gradient energy in a superconductor lacking inversion symmetry has unusual structure. The general formalism is illustrated using as an example CePt$_3$Si, which is the first known heavy-fermion superconductor without an inversion center.Comment: Published version, 14 pages, minor correction