408 research outputs found
Blindness incidence in Germany - A population-based study from WĂĽrttemberg-Hohenzollern
Few data on the incidence of blindness in Germany are available. We analysed causes of legal blindness for the region WĂĽrttemberg-Hohenzollern (population 5.5 million) in order to help fill in this gap. Material and Methods: Population-based investigation on the incidence of legal blindness (visual acuity <1/50) based on materials from the social servies. Age-dependent blindness incidences were modelled via logistic regression models. Results: 647 blind persons were newly registered in 1994 (blindness incidence 11.6/100,000). The blindness incidence is moderate in infants (4.5/100,000) and decreases further during childhood. At the age of 20 years, the incidence again rises to the former level and remains relatively constant. After the age of 60 years, the incidence increases sharply: 5-year odds ratios are 1.76 (CI: 1.68-1.85) in women and 1.72 (CI: 1.60-1.84) in men. The blindness incidence is higher in women, 15.6/100,000, compared to 12.2/100,000 in men. The major causes of blindness are: macular degeneration, 3.92/100,000; diabetic retinopathy, 2.01/100,000; glaucoma, 1.6/100,000; high myopia, 0.77/100,000; optic atrophy, 0.68/100,000; central nervous system-triggered blindness; 0.56/100,000, and tapetoretinal degenerations, 0.52/100,000. Discussion: Due to monetary incentives for the blind persons, social service files offer accurate and complete data. Besides macular degeneration, glaucoma and dia betic retinopathy are major causes of blindness. Thus, this study suggests further blindness prevention activities for diabetic retinopathy and glaucoma
Effect of Growth Hormone (hGH) Replacement Therapy on Physical Work Capacity and Cardiac and Pulmonary Function in Patients with hGH Deficiency Acquired in Adulthood.
The effects of 6 months of replacement therapy with recombinant human GH (hGH) on physical work capacity and cardiac structure and function were investigated in 20 patients with hGH deficiency of adult onset in a double blind, placebo-controlled trial. The GH dose of 12.5 micrograms/kg BW was self-administered daily sc. Oxygen consumption (VO2), CO2 production, and ventilatory volumes were measured during exercise on a bicycle spiroergometer. M-Mode echocardiography was performed using standard techniques. The VO2 max data, expressed per kg BW (mL/min.kg BW) showed a significant increase from 23.2 +/- 2.4 to 30.0 +/- 2.3 (P < 0.01) in the hGH-treated group, whereas the VO2 max data, expressed per lean body mass (milliliters per min/kg lean body mass) did not change significantly in either group. Maximal O2 pulse (milliliters per beat) increased significantly from 15.2 +/- 5.6 to 19.6 +/- 3.3 mL/beat (P < 0.01), but remained constant in the placebo group. The maximal power output (watts +/- SE) increased significantly (P < 0.01) from 192.5 +/- 13.5 to 227.5 +/- 11.5 in the hGH-treated group, but remained constant in the placebo group. Cardiac structure (left ventricular posterior wall, interventricular septum thickness, left ventricular mass, left ventricular end-systolic dimension, and left ventricular end-diastolic dimension) as well as echocardiographically assessed cardiac function did not change significantly after 6 months of treatment in either group. We conclude that hGH replacement in hGH-deficient adults improves oxygen uptake and exercise capacity. These improvements in pulmonary parameters might be due to an increase in respiratory muscle strength and partly to the changes in muscle volume per se observed during hGH replacement therapy. Furthermore, an increased cardiac output might contribute to the improvement in exercise performance during hGH treatment. According to our data, hGH replacement therapy leads to an improvement of exercise capacity and maximal oxygen uptake, but has no significant effect on cardiac structure
Relation between Brown Dwarfs and Exoplanets
One of the most debated subjects in Astronomy since the discovery of
exoplanets is how can we distinguish the most massive of such objects from
very-low mass stars like Brown Dwarfs (BDs)? We have been looking for evidences
of a difference in physical characteristics that could be related to different
formation processes. Using a new diagnostic diagram that compares the baryonic
gravitational potential (BGP) with the distances from their host stars, we have
classified a sample of 355 well-studied exoplanets according to their possible
structures. We have then compared the exoplanets to a sample of 87 confirmed
BDs, identifying a range in BGP that could be common to both objects. By
analyzing the mass-radius relations (MRR) of the exoplanets and BDs in those
different BGP ranges, we were able to distinguish different characteristic
behaviors. By comparing with models in the literature, our results suggest that
BDs and massive exoplanets might have similar structures dominated by liquid
metallic hydrogen (LMH).Comment: Poster #149 from proceeding of The 19th Cambridge Workshop on Cool
Stars, Stellar Systems, and the Sun; 06-10 June 2016, Uppsala, Swede
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Impact of disorder on dynamics and ordering in the honeycomb-lattice iridate Na2IrO3
Kitaev's honeycomb spin-liquid model and its proposed realization in materials such as α-RuCl3, Li2IrO3, and Na2IrO3 continue to present open questions about how the dynamics of a spin liquid are modified in the presence of non-Kitaev interactions as well as the presence of inhomogeneities. Here we use Na23 nuclear magnetic resonance to probe both static and dynamical magnetic properties in single-crystal Na2IrO3. We find that the NMR shift follows the bulk susceptibility above 30 K but deviates from it below; moreover below TN the spectra show a broad distribution of internal magnetic fields. Both of these results provide evidence for inequivalent magnetic sites at low temperature, suggesting inhomogeneities are important for the magnetism. The spin-lattice relaxation rate is isotropic and diverges at TN, suggesting that the Kitaev cubic axes may control the critical quantum spin fluctuations. In the ordered state, we observe gapless excitations, which may arise from site substitution, emergent defects from milder disorder, or possibly be associated with nearby quantum paramagnetic states distinct from the Kitaev spin liquid
Evolution of two-gap behavior of the superconductor FeSe_1-x
The superfluid density, \rho_s, of the iron chalcogenide superconductor,
FeSe_1-x, was studied as a function of pressure by means of muon-spin rotation.
The zero-temperature value of \rho_s increases with increasing transition
temperature T_c (increasing pressure) following the tendency observed for
various Fe-based and cuprate superconductors. The analysis of \rho_s(T) within
the two-gap scheme reveals that the effect on both, T_c and \rho_s(0), is
entirely determined by the band(s) where the large superconducting gap
develops, while the band(s) with the small gap become practically unaffected.Comment: 5 pages, 3 figure
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Water use indicators at farm scale: Methodology and case study
Indicators for water use at farm scale can assist farmers in understanding the water flows on their farms and in optimizing water use by adapting agronomic measures and farm management. The objective of this work is to develop a methodology to estimate water flows at the farm scale, to derive indicators for farm water use, and to apply them in a first case study. After the spatial and temporal boundaries of the farm system and the water flows are defined, three indicators to assess water use at the farm scale are developed: farm water productivity, degree of water utilization, and specific inflow of technical water. Farm water productivity describes the ratio of farm output to water input, where the water input is the total of those water inflows into the farm system that can be assigned to the generation of farm output. Farm output is expressed on a mass basis, food energy basis, and monetary basis. The degree of water utilization characterizes the relationship between productive water to the total water inflow into the farm system, where productive water comprises those water flows that directly contribute to biomass generation via plant and animal metabolism. The specific technical water inflow quantifies the water inflow into the system by technical means relative to the farm area. The application of the methodology in a first case study for a mixed crop-livestock farm with 2869 ha in Germany results in a farm water productivity of 2.30 kg fresh mass per mWinput-3, 1.03 kg dry mass per m Winput-3, 5.96 GJ m Winput-3, and 0.25 € mWinput-3. The degree of water utilization is 0.56. The specific technical water inflow is 36.5 m3 ha-1 year -1. Factors that mainly effect these indicators and general approaches to optimize water use in farms are discussed as well as the further research required for practical implementation
Pressure Induced Static Magnetic Order in Superconducting FeSe_1-x
We report on a detailed investigation of the electronic phase diagram of
FeSe_1-x under pressures up to 1.4GPa by means of AC magnetization and
muon-spin rotation. At a pressure \simeq0.8GPa the non-magnetic and
superconducting FeSe_1-x enters a region where long range static magnetic order
is realized above T_c and bulk superconductivity coexists and competes on short
length scales with the magnetic order below T_c. For even higher pressures an
enhancement of both the magnetic and the superconducting transition
temperatures as well as of the corresponding order parameters is observed.
These exceptional properties make FeSe1-x to be one of the most interesting
superconducting systems investigated extensively at present.Comment: 5 pages, 3 figure
Giant spin canting in the S = 1/2 antiferromagnetic chain [CuPM(NO3)2(H2O)2]n observed by 13C-NMR
We present a combined experimental and theoretical study on copper pyrimidine
dinitrate [CuPM(NO3)2(H2O)2]n, a one-dimensional S = 1/2 antiferromagnet with
alternating local symmetry. From the local susceptibility measured by NMR at
the three inequivalent carbon sites in the pyrimidine molecule we deduce a
giant spin canting, i.e., an additional staggered magnetization perpendicular
to the applied external field at low temperatures. The magnitude of the
transverse magnetization, the spin canting of 52 degrees at 10 K and 9.3 T and
its temperature dependence are in excellent agreement with exact
diagonalization calculations.Comment: 5 pages, 6 Postscript figure
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