951 research outputs found

    Quantitative studies for photoabsorption and fluorescence of HCl

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    Photoabsorption and fluorescence cross sections of HCl are investigated in the wavelength region between 105 to 220 nm. The oscillator strengths of discrete structures at wavelengths shorter than 130 nm are measured

    The emission of oxygen green line and density of O atom determined by using ISUAL and SABER measurements

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    Emissions of the 557.7 nm green line airglow observed by the ISUAL (Imager of Sprites and Upper Atmospheric Lightning) instrument on board the FORMOSAT-2 satellite in May and November 2008 are studied here to derive the density distributions of the atomic oxygen by using atmospheric parameters from MSISE-00 model and TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics)/SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) measurements. The May observations were made in 10 days from a fixed orbit of longitude (100° E) with the results showing emission rate and O atom density both peaked at heights of about 90 km over 10° to 20° latitudes in the Northern Hemisphere (NH). In the Southern Hemisphere (SH), the emission rate and density of O atom are both low compared with those in NH. In November, the observations were made as the satellite traveled over all 14 orbits around the earth, covering all longitudes and latitudes of 25° S–45° N. Strong peaks of emission rates and O atoms are found at heights of about 95 km in the mid-latitudes in both hemispheres. In the equator, the airglow layer has a weaker emission rate but with higher altitude compared with those of mid-latitudes. In the lower and upper mesosphere at heights below 85 km and above 105 km, there are more O atoms in the equatorial regions than in the mid-latitudes. And there is a good correlation between the O atom and the temperature structure. A comparison with O atom distribution derived from OH airglow observed by TIMED/SABER at about the same time shows similar results

    Randomized comparative study of conventional minilaparoscopy (5mm) versus modern minilaparoscopy (2.9mm) in patients of infertility

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    Background: To compare diagnostic conventional minilaparoscopy (5mm) with diagnostic modern minilaparoscopy (2.9mm) in patients of infertility in terms of operating time, post-operative pain, hospital stay.Methods: A prospective randomized comparative study was done in a tertiary care centre involving eighty patients of infertility undergoing diagnostic laparoscopy. Diagnostic laparoscopy was done using 5mm laparoscope (Conventional minilaparoscope-Group I) in 40 patients and using 2.9mm laparoscope (Modern minilaparoscope-Group II) in 40 patients. Operating time was measured from the point of skin incision to closure, post op pain was assessed with VAS scoring system, total hours of hospital stay from shifting to day care recovery ward till discharge was noted.Results: Both conventional minilaroscope and modern minilaparoscopes were comparable to each other. Operating time in both groups was similar (7.7min in Group I vs 8.7min in Group II). In both groups, there was no statistically significant difference in post-operative pain as assessed by VAS scoring System (39 in Group I vs 38 in Group II had mild post-op pain and 1 in Group I vs 2 in Group II had moderate pain). The difference in duration of post-op hospital stay in both Group I and group II was not statistically significant (3.5 hours vs 3.3 hours).Conclusions: Both conventional minilaparoscopy (5mm laparoscope) and modern miniaparoscopy (2.9mm laparoscope) are comparable with respect operating time, post-op pain, hospital stay. Modern minilaparoscope is no better than conventional minilaparoscope

    Network effects, cooperation and entrepreneurial innovation in China

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    The rapid rise of an innovative private manufacturing economy in China challenges standard economic explanations of growth, which typically assume the existence of well-defined formal institutions such as property rights and company laws safeguarding investor and creditor interests. We highlight the social structure of cooperation that enables innovative activity in private manufacturing firms when formal property rights protection remains weak. We show how network effects linked to inter-firm cooperation in industrial clusters allowed private entrepreneurs to quickly develop reliable business norms to reduce the inherent risk of malfeasance and contract breach in formal and informal collaborative efforts. Survey data from a sample of 700 manufacturing firms located in China’s Yangzi Delta region confirms that both formal and informal types of inter-firm collaboration are effective, though in different areas of innovative activity

    Species Abundance Patterns in Complex Evolutionary Dynamics

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    An analytic theory of species abundance patterns (SAPs) in biological networks is presented. The theory is based on multispecies replicator dynamics equivalent to the Lotka-Volterra equation, with diverse interspecies interactions. Various SAPs observed in nature are derived from a single parameter. The abundance distribution is formed like a widely observed left-skewed lognormal distribution. As the model has a general form, the result can be applied to similar patterns in other complex biological networks, e.g. gene expression.Comment: 4 pages, 3 figures. Physical Review Letters, in pres

    Phenotypic and molecular evaluation of maize (Zea may L.) genotypes under field conditions in the Volta region of Ghana

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    Maize streak disease (MSD) is the most devastating and destructive disease of maize (Zea mays L.) in sub-Saharan Africa (SSA). Field trials were conducted in the 2014 minor and 2015 major cropping seasons to screen 16 and 17 maize genotypes, respectively, for high yield and resistance to maize streak virus (MSV) infections. The plants were scored for disease severity at 4, 6, 8 and 10 weeks after planting (WAP) based on a 1-5 visual scale (1= No infection and 5= Very severe infection). Polymerase chain reaction (PCR) test was done to detect the presence of MSV in the diseased leaf samples in order to confirm field resistance. Both phenotypic and PCR test revealed that all the maize genotypes tested in the study were infected by MSV. There was a significant varietal effect on the incidence and severity of MSD in both the major and minor seasonal trials. Genotypes ‘Abontem’,’Aburohemaa’, ‘Akposoe’, ‘Dapango’, ‘Dorke’, ‘Etubi’, ‘Honampa’, ‘Mamaba’, ‘Obatanpa’, ‘Omankwa’ and PAN 12 showed mild disease symptoms during both major and minor cropping seasons. On the other hand, genotypes ‘Dormabin’, ‘Dzinu-Eve’, ‘Enibi’, Keta 60 and PAN 53 exhibited moderate to severe symptoms during the two cropping seasons. Incidence and severity of MSD were significantly higher in the minor season than in the major season, indicating a significant seasonal effect of MSV on the maize genotypes. The yield and yield components were observed to vary significantly among the different maize genotypes and between the cropping seasons with mean yields significantly higher in the major season than in the minor season. Genotypes ‘Abontem’, ‘Aburohemaa’, ‘Akposoe’, ‘Dorke’, ‘Etubi’, ‘Honampa’, ‘Omankwa’, ‘Obatanpa’ and PAN 12 (All improved varieties), which exhibited partial resistance to MSV infection gave high seed yields during both seasons. The improved maize genotypes that were high yielding and resistant to MSV infection should be evaluated for uniform yield trials on farmers’ fields towards their release as varieties to farmers

    Surfaces roughness effects on the transmission of Gaussian beams by anisotropic parallel plates

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    Influence of the plate surfaces roughness in precise ellipsometry experiments is studied. The realistic case of a Gaussian laser beam crossing a uniaxial platelet is considered. Expression for the transmittance is determined using the first order perturbation theory. In this frame, it is shown that interference takes place between the specular transmitted beam and the scattered field. This effect is due to the angular distribution of the Gaussian beam and is of first order in the roughness over wavelength ratio. As an application, a numerical simulation of the effects of quartz roughness surfaces at normal incidence is provided. The interference term is found to be strongly connected to the random nature of the surface roughness.Comment: 18 pages, Journal of Physics D: Applied Physics, volume 36, issue 21, pages 2697 - 270

    Andreev Reflection in Strong Magnetic Fields

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    We have studied the interplay of Andreev reflection and cyclotron motion of quasiparticles at a superconductor-normal-metal interface with a strong magnetic field applied parallel to the interface. Bound states are formed due to the confinement introduced both by the external magnetic field and the superconducting gap. These bound states are a coherent superposition of electron and hole edge excitations similar to those realized in finite quantum-Hall samples. We find the energy spectrum for these Andreev edge states and calculate transport properties.Comment: 5 pages, 3 figures, RevTex, revised to include more detailed discussion of currents and transpor
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