Oblique surface waves at an interface of metal-dielectric superlattice and isotropic dielectric

We investigate the existence and the dispersion characteristics of surface waves that propagate at an interface between metal-dielectric superlattice and isotropic dielectric. Within the long wavelength limit, when the effective-medium approximation is valid, the superlattice behaves like a uniaxial plasmonic crystal with the main optical axes perpendicular to the metal-dielectric interfaces. We demonstrate that if such a semi-infinite plasmonic crystal is cut normally to the layer interfaces and brought into the contact with semi-infinite dielectric, a new type of surface modes can appear. The propagation of such modes obliquely to the optical axes occurs under favorable conditions that regard thicknesses of the layers, as well as the proper choice of dielectric permittivity of the constituent materials. We show that losses within the metallic layers can be substantially reduced by making the layers sufficiently thin. At the same time, a dramatic enlargement of the range of angles for oblique propagation of the new surface modes is observed. This can lead, however, to the field non-locality and consequently to the failure of the effective-medium approximation.Comment: 4 pages, 3 figure

Superconducting film with randomly magnetized dots: A realization of the 2D XY model with random phase shifts

We consider a thin superconducting film with randomly magnetized dots on top of it. The dots produce a disordered pinning potential for vortices in the film. We show that for dots with permanent and random magnetization normal or parallel to the film surface, our system is an experimental realization of the two-dimensional XY model with random phase shifts. The low-temperature superconducting phase, that exists without magnetic dots, survives in the presence of magnetic dots for sufficiently small disorder.Comment: 5 pages, 1 figur

Dijagnoza, anestezija i operativni zahvat kod rupture mokraćne bešike novorođene ždrebadi

This study describes methods for the diagnosis, anesthesia and operative repair in 4 neonatal foals with urinary bladder rupture. Diagnosis was based on case history, clinical signs, changes in serum chemistry analyzes (hyponatremia, hyperkalemia, hypochloremia, metabolic acidosis and increased serum creatinine and urea nitrogen levels), abdominocentesis, ultrasound and electrocardiographs. As electrolyte abnormalities and acid-base derangement can lead to the development of cardiac arrhythmia during general anesthesia, surgical treatment of urinary bladder rupture in neonatal foals should be performed when the animal's condition has been stabilized. This includes infusion of physiological saline solution, 5 % glucose infusion with insulin (0.1U/kg) and 1.4% sodiumdrogencarbonate.Ova studija opsuje dijagnostikovanje, anesteziju i operativni tretman pri rupturi mokraćne bešike novorođene ždrebadi. Dijagnoza je zasnovana na istoriji bolesti, kliničkim simptomima, promenama u serumu ustanovljenim biohemijskim analizama (hiponatrijemija, hipokalijemija, hipohloremija, metabolička acidoza sa porastom nivoa serumskog kreatinina i ureje), abdominocintezi, ultrazvuku i elektrokardiografiji. Kao što poremećaji elektrolita i acido-bazne ravnoteže mogu dovesti do pojave srčane aritmije u toku opšte anestezije, hirurški tretman rupture bešike kod novorođene ždrebadi može biti primenjen kada je stabilizovano zdravstveno stanje životinje. Ovo uključuje infuziju fiziološkog rastvora, 5% glukoze sa insulinom (0,1 U/kg) i 1,4% Na-bikarbonat

Phase transition of interacting disordered bosons in one dimension

Interacting bosons generically form a superfluid state. In the presence of disorder it can get converted into a compressible Bose glass state. Here we study such transition in one dimension at moderate interaction using bosonization and renormalization group techniques. We derive the two-loop scaling equations and discuss the phase diagram. We find that the correlation functions at the transition are characterized by universal exponents in a finite region around the fixed point.Comment: five pages and two pages and one figur

Spectroscopic insensitivity to cold collisions in a two-state mixture of fermions

We have experimentally demonstrated the absence of spectroscopic resonance shifts in a mixture of two interacting Fermi gases. This result is linked to observations in an ultracold gas of thermal bosons. There, the measured resonance shift due to interstate collisions is independent of the coherence in the system, and twice that expected from the equilibrium energy splitting between the two states in a fully decohered cloud. We give a simple theoretical explanation of these observations, which elucidates the effect of coherent radiation on an incoherent mixture of atoms

Regulation and Restoration of Motoneuronal Synaptic Transmission During Neuromuscular Regeneration in the Pulmonate Snail Helisoma trivolvis

Regeneration of motor systems involves reestablishment of central control networks, reinnervation of muscle targets by motoneurons, and reconnection of neuromodulatory circuits. Still, how these processes are integrated as motor function is restored during regeneration remains ill defined. Here, we examined the mechanisms underlying motoneuronal regeneration of neuromuscular synapses related to feeding movements in the pulmonate snail Helisoma trivolvis. Neurons B19 and B110, although activated during different phases of the feeding pattern, innervate similar sets of muscles. However, the percentage of muscle fibers innervated, the efficacy of excitatory junction potentials, and the strength of muscle contractions were different for each cell’s specific connections. After peripheral nerve crush, a sequence of transient electrical and chemical connections formed centrally within the buccal ganglia. Neuromuscular synapse regeneration involved a three-phase process: the emergence of spontaneous synaptic transmission (P1), the acquisition of evoked potentials of weak efficacy (P2), and the establishment of functional reinnervation (P3). Differential synaptic efficacy at muscle contacts was recapitulated in cell culture. Differences in motoneuronal presynaptic properties (i.e., quantal content) were the basis of disparate neuromuscular synapse function, suggesting a role for retrograde target influences. We propose a homeostatic model of molluscan motor system regeneration. This model has three restoration events: (1) transient central synaptogenesis during axonal outgrowth, (2) intermotoneuronal inhibitory synaptogenesis during initial neuromuscular synapse formation, and (3) target-dependent regulation of neuromuscular junction formation

Transport Parameters of F- Ions in BF3

In this work we presented the new results for energy dependent cross-sections and transport coefficients as a function of E/N for F- ions in BF3 gas. Results were obtained by using the Monte Carlo technique for cross-section set determined on the basis of the Nanbu theory. Monte Carlo method is applied to obtain swarm parameters at temperature of T = 300 K

Anomalous Diffusion at Edge and Core of a Magnetized Cold Plasma

Progress in the theory of anomalous diffusion in weakly turbulent cold magnetized plasmas is explained. Several proposed models advanced in the literature are discussed. Emphasis is put on a new proposed mechanism for anomalous diffusion transport mechanism based on the coupled action of conductive walls (excluding electrodes) bounding the plasma drain current (edge diffusion) together with the magnetic field flux "cutting" the area traced by the charged particles in their orbital motion. The same reasoning is shown to apply to the plasma core anomalous diffusion. The proposed mechanism is expected to be valid in regimes when plasma diffusion scales as Bohm diffusion and at high $B/N$, when collisions are of secondary importance.Comment: 9 pages, 4 figure

Two-Species Reaction-Diffusion System with Equal Diffusion Constants: Anomalous Density Decay at Large Times

We study a two-species reaction-diffusion model where A+A->0, A+B->0 and B+B->0, with annihilation rates lambda0, delta0 > lambda0 and lambda0, respectively. The initial particle configuration is taken to be randomly mixed with mean densities nA(0) > nB(0), and with the two species A and B diffusing with the same diffusion constant. A field-theoretic renormalization group analysis suggests that, contrary to expectation, the large-time density of the minority species decays at the same rate as the majority when d<=2. Monte Carlo data supports the field theory prediction in d=1, while in d=2 the logarithmically slow convergence to the large-time asymptotics makes a numerical test difficult.Comment: revised version (more figures, claim on exactnes of d=2 treatment removed), 5 pages, 3 figures, RevTex, see related paper Phys. Rev. E, R3787, (1999) or cond-mat/9901147, to appear in Phys. Rev.