Convective plan-form two-scale dynamos in a plane layer

We study generation of magnetic fields, involving large spatial scales, by convective plan-forms in a horizontal layer. Magnetic modes and their growth rates are expanded in power series in the scale ratio, and the magnetic eddy diffusivity (MED) tensor is derived for flows, symmetric about the vertical axis in a layer. For convective rolls magnetic eddy correction is demonstrated to be always positive. For rectangular cell patterns, the region in the parameter space of negative MED coincides with that of small-scale magnetic field generation. No instances of negative MED in hexagonal cells are found. A family of plan-forms with a smaller symmetry group than that of rectangular cell patterns has been found numerically, where MED is negative for molecular magnetic diffusivity over the threshold for the onset of small-scale magnetic field generation.Comment: Latex. 24 pages with 3 Postscript figures, 19 references. Final version (expanded Appendix 2, 4 references added, notation changed to a more "user-friendly"), accepted in Geophysical and Astrophysical Fluid Dynamic

Detection of arcs in Saturn's F ring during the 1995 Sun ring-plane crossing

Observations of the November 1995 Sun crossing of the Saturn's ring-plane made with the 3.6m CFH telescope, using the UHAO adaptive optics system, are presented here. We report the detection of four arcs located in the vicinity of the F ring. They can be seen one day later in HST images. The combination of both data sets gives accurate determinations of their orbits. Semi-major axes range from 140020 km to 140080 km, with a mean of 140060 +- 60 km. This is about 150 km smaller than previous estimates of the F ring radius from Voyager 1 and 2 data, but close to the orbit of another arc observed at the same epoch in HST images.Comment: 8 pages, 3 figures, 1 table, To appear in A&A, for comments : [email protected]

The TWA 3 Young Triple System: Orbits, Disks, Evolution

We have characterized the spectroscopic orbit of the TWA 3A binary and provide preliminary families of probable solutions for the TWA 3A visual orbit as well as for the wide TWA 3A--B orbit. TWA 3 is a hierarchical triple located at 34 pc in the $\sim$10 Myr old TW Hya association. The wide component separation is 1."55; the close pair was first identified as a possible binary almost 20 years ago. We initially identified the 35-day period orbital solution using high-resolution infrared spectroscopy which angularly resolved the A and B components. We then refined the preliminary orbit by combining the infrared data with a re-analysis of our high-resolution optical spectroscopy. The orbital period from the combined spectroscopic solution is $\sim$35 days, the eccentricity is $\sim$0.63, and the mass ratio is $\sim$0.84; although this high mass ratio would suggest that optical spectroscopy alone should be sufficient to identify the orbital solution, the presence of the tertiary B component likely introduced confusion in the blended optical spectra. Using millimeter imaging from the literature, we also estimate the inclinations of the stellar orbital planes with respect to the TWA 3A circumbinary disk inclination and find that all three planes are likely misaligned by at least $\sim$30 degrees. The TWA 3A spectroscopic binary components have spectral types of M4.0 and M4.5; TWA 3B is an M3. We speculate that the system formed as a triple, is bound, and that its properties were shaped by dynamical interactions between the inclined orbits and disk.Comment: Accepted to Ap

Medical Treatment of Nocturia in Men with Lower Urinary Tract Symptoms : Systematic Review by the European Association of Urology Guidelines Panel for Male Lower Urinary Tract Symptoms

Context: The treatment of nocturia is a key challenge due to the multi-factorial pathophysiology of the symptom and the disparate outcome measures used in research. Objective: To assess and compare available therapy options for nocturia, in terms of symptom severity and quality of life. Evidence acquisition: Medical databases (Embase, Medline, Cochrane Systematic Reviews, Cochrane Central) were searched with no date restriction. Comparative studies were included which studied adult men with nocturia as the primary presentation and lower urinary tract symptoms including nocturia or nocturnal polyuria. Outcomes were symptom severity, quality of life, and harms. Evidence synthesis: We identified 44 articles. Antidiuretic therapy using dose titration was more effective than placebo in relation to nocturnal voiding frequency and duration of undisturbed sleep; baseline serum sodium is a key selection criterion. Screening for hyponatremia (<130 mmol/l) must be undertaken at baseline, after initiation or dose titration, and during treatment. Medications to treat lower urinary tract dysfunction (alpha-1 adrenergic antagonists, 5-alpha reductase inhibitors, phosphodiesterase type 5inhibitor, antimuscarinics, beta-3 agonist, and phytotherapy) were generally not significantly better than placebo in short-term use. Benefits with combination therapies were not consistently observed. Other medications (diuretics, agents to promote sleep, nonsteroidal anti-inflammatories) were sometimes associated with response or quality of life improvement. The recommendations of the Guideline Panel are presented. Conclusions: Issues of trial designmake therapy of nocturia a challenging topic. The range of contributory factors relevant in nocturia makes it desirable to identify predictors of response to guide therapy. Consistent responses were reported for titrated antidiuretic therapy. For other therapies, responses were less certain, and potentially of limited clinical benefit. Patient summary: This review provides an overview of the current drug treatments of nocturia, which is the need to wake at night to pass urine. The symptom can be caused by several different medical conditions, and measuring its severity and impact varies in separate research studies. No single treatment deals with the symptom in all contexts, and careful assessment is essential to make suitable treatment selection. (C) 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.Peer reviewe

Origin and Evolution of Saturn's Ring System

The origin and long-term evolution of Saturn's rings is still an unsolved problem in modern planetary science. In this chapter we review the current state of our knowledge on this long-standing question for the main rings (A, Cassini Division, B, C), the F Ring, and the diffuse rings (E and G). During the Voyager era, models of evolutionary processes affecting the rings on long time scales (erosion, viscous spreading, accretion, ballistic transport, etc.) had suggested that Saturn's rings are not older than 100 My. In addition, Saturn's large system of diffuse rings has been thought to be the result of material loss from one or more of Saturn's satellites. In the Cassini era, high spatial and spectral resolution data have allowed progress to be made on some of these questions. Discoveries such as the ''propellers'' in the A ring, the shape of ring-embedded moonlets, the clumps in the F Ring, and Enceladus' plume provide new constraints on evolutionary processes in Saturn's rings. At the same time, advances in numerical simulations over the last 20 years have opened the way to realistic models of the rings's fine scale structure, and progress in our understanding of the formation of the Solar System provides a better-defined historical context in which to understand ring formation. All these elements have important implications for the origin and long-term evolution of Saturn's rings. They strengthen the idea that Saturn's rings are very dynamical and rapidly evolving, while new arguments suggest that the rings could be older than previously believed, provided that they are regularly renewed. Key evolutionary processes, timescales and possible scenarios for the rings's origin are reviewed in the light of tComment: Chapter 17 of the book ''Saturn After Cassini-Huygens'' Saturn from Cassini-Huygens, Dougherty, M.K.; Esposito, L.W.; Krimigis, S.M. (Ed.) (2009) 537-57

Assessment of actual nutrition among children with multiple milk teeth caries attending preschool educational institutions

The purpose of the study is to assess the actual nutrition of preschool children with multiple caries of milk teeth.Цель исследования – оценить фактическое питание детей и обеспеченность витамином D у детей дошкольного возраста с множественным кариесом молочных зубов