403 research outputs found

    Review of social science literature on risk and vulnerability to HIV/AIDS in fishing communities in Sub-Saharan Africa

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    The WorldFish Center and FAO are implementing a regional programme entitled "Fisheries and HIV/AIDS in Africa; investing in sustainable solutions", funded by the Swedish International Development Cooperation Agency (Sida) and the Norwegian Ministry of Foreign Affairs. As part of this project, the Overseas Development Group/School of Development Studies was asked to produce a literature review on 'Fisheries and HIV/AIDS in Africa: evidence from social science, medical and policy research'. The task was to collate available data from socio-economic and medical research to identify trends in fishing communities in Sub-Saharan Africa. This paper is the second of three parts of the literature review, which covers review of social science research on risk and vulnerability to HIV/AIDS in the fisheries sector in Sub-Saharan AfricaFisheries, AIDS, Public health, HIV, Nutritive value

    Multiscale Morphological Filtering for Analysis of Noisy and Complex Images

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    Images acquired with passive sensing techniques suffer from illumination variations and poor local contrasts that create major difficulties in interpretation and identification tasks. On the other hand, images acquired with active sensing techniques based on monochromatic illumination are degraded with speckle noise. Mathematical morphology offers elegant techniques to handle a wide range of image degradation problems. Unlike linear filters, morphological filters do not blur the edges and hence maintain higher image resolution. Their rich mathematical framework facilitates the design and analysis of these filters as well as their hardware implementation. Morphological filters are easier to implement and are more cost effective and efficient than several conventional linear filters. Morphological filters to remove speckle noise while maintaining high resolution and preserving thin image regions that are particularly vulnerable to speckle noise were developed and applied to SAR imagery. These filters used combination of linear (one-dimensional) structuring elements in different (typically four) orientations. Although this approach preserves more details than the simple morphological filters using two-dimensional structuring elements, the limited orientations of one-dimensional elements approximate the fine details of the region boundaries. A more robust filter designed recently overcomes the limitation of the fixed orientations. This filter uses a combination of concave and convex structuring elements. Morphological operators are also useful in extracting features from visible and infrared imagery. A multiresolution image pyramid obtained with successive filtering and a subsampling process aids in the removal of the illumination variations and enhances local contrasts. A morphology-based interpolation scheme was also introduced to reduce intensity discontinuities created in any morphological filtering task. The generality of morphological filtering techniques in extracting information from a wide variety of images obtained with active and passive sensing techniques is discussed. Such techniques are particularly useful in obtaining more information from fusion of complex images by different sensors such as SAR, visible, and infrared

    Using Latent Growth Modeling to Understand Longitudinal Effects in MIS Theory: A Primer

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    The use of structural equation modeling (SEM) has grown dramatically in the field of management information systems (MIS) in the past twenty years, but SEM’s focus has been primarily on cross-sectional data sets. Functionally, SEM has been used to test measurement and path models, but the SEM approach has not been applied to repeated measures designs. In this article, we describe latent growth models (LGMs), an extension of SEM, which focuses on how observed and/or latent variables change over time. The purpose of this paper is to provide a primer on the use of LGMs, as well as to advocate for its use to extend MIS theory. We illustrate several flexible applications of LGMs using longitudinal data, including conditional, unconditional, and dual growth models. We discuss the advantages of using LGMs over other more traditional longitudinal approaches, and highlight areas in MIS where researchers can use this technique effectively

    Biotechnological advances in Vitex species, and future perspectives

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    AbstractVitex is a large genus consisting of 230 species of trees and shrubs with multiple (ornamental, ethnobotanic and pharmacological) uses. Despite this, micropropagation has only been used to effectively propagate and preserve germplasm a limited number (six) of Vitex species (V. agnus-castus, V. doniana, V. glabrata, V. negundo, V. rotundifolia, V. trifolia). This review on Vitex provides details of published micropropagation protocols and perspectives on their application to germplasm preservation and in vitro conservation. Such details serve as a practically useful user manual for Vitex researchers. The importance of micropropagation and its application to synthetic seed production, in vitro flowering, production of secondary metabolites, and the use of molecular markers to detect somaclonal variation in vitro, are also highlighted

    Disease and pest management in apple: Farmers' perception and adoption in J&K state

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    Diseases and pests are one of the limiting factors for low productivity of the fruit crops in Kashmir valley, India. A study on management of resources with respect to disease and pest management of apple and extent of adoption of recommended plant protection technology was undertaken for increasing apple production in Kashmir valley of J and K State. District Baramulla was selected purposively on the basis of maximum area and production under apple crop. A sample size of 200 apple growers 50 each from 4 villages were selected randomly. The study revealed that the perception index regarding attributes of technology recommended in two diseases viz. San Jose Scale and Apple Scab was 68.88% and 80.76% in respect of profitability (83.97%), simplicity-complexity each 63.57% and 54.27 % for practicability attributes of technology. The data further showed that the farmers adoption level under Chemical control was high at silver tip to green tip stage (80%) and fruit let pea size stage (78%) and medium adoption was observed at pink bloom (bud) stage (74%), petal fall stage (74%) walnut size apple stage (70%) on Apple Scab similarly, the extent of adoption was low (45%) for mechanical and no chemical control measures under clean cultivation. In case of San Jose Scale the farmers adoption level regarding name of chemical, its dose, quantity of water required per acre for preparing spray solution and time of spray at late dormant spray, (feb, March) was high (80%). The findings will help to improve the level of farmers’ knowledge to increase apple production in Kashmir valley

    Electron refraction at lateral atomic interfaces

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    We present theoretical simulations of electron refraction at the lateral atomic interface between a “homogeneous” Cu(111) surface and the “nanostructured” one-monolayer (ML) Ag/Cu(111) dislocation lattice. Calculations are performed for electron binding energies barely below the 1 ML Ag/ Cu(111) M-point gap (binding energy EB ÂŒ53 meV, below the Fermi level) and slightly above its C -point energy (EB ÂŒ160 meV), both characterized by isotropic/circular constant energy surfaces. Using plane-wave-expansion and boundary-element methods, we show that electron refraction occurs at the interface, the Snell law is obeyed, and a total internal reflection occurs beyond the critical angle. Additionally, a weak negative refraction is observed for EB ÂŒ53 meV electron energy at beam incidence higher than the critical angle. Such an interesting observation stems from the interface phase-matching and momentum conservation with the umklapp bands at the second Brillouin zone of the dislocation lattice. The present analysis is not restricted to our Cu-Ag/Cu model system but can be readily extended to technologically relevant interfaces with spinpolarized, highly featured, and anisotropic constant energy contours, such as those characteristic for Rashba systems and topological insulators. Published by AIP Publishing.Peer ReviewedPostprint (published version

    Sol gel synthesis and photoluminescence study of Eu3+ doped SnO2

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    Tin oxide(IV) nanophosphor doped with europium had been prepared by sol-gel technique using SnCl4 as precurser. XRD, IR, SEMand TEM analyses were used for characterization of SnO2:Eu3+. The XRD analysis shows that well crystallized tetragonal rutile SnO2:Eu3+ can be obtained by this method and the crystal size was about 15-20nm as an average for the sample calcined at 400ºC for 2h. The evolution of the most important functional groups during the steps involved in this synthesis route is explained in view of the results obtained with FTIR and XRD.  A spherical like morphology of the prepared  SnO2 nanoparticles was observed in the SEM and TEM studies. The SnO2 nanoparticles show stable photoluminescence emission intensity at 612 nm (5D0/7F2) of the Eu3+ ions activated SnO2 nanocrystals  This paper discuss the mechanistic approach of origin of luminescence in SnO2

    Enhancement of Rectenna Performance using Artificial Magnetic Conductor for Energy Harvesting Applications

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    This paper brings together an understanding on Artificial Magnetic Conductor (AMC) and rectenna in energy harvesting applications. The rectenna is built upon a combination of a low profile antenna like dipole or patch microstrip with the presence of a rectifying circuit as well as a filter to act as an RF to DC converter. In wireless power transmission, the focal problem is that the total capture of the RF energy is totally low. Thus, with the aim of capturing maximum power, the receiving antenna is supposed to be designed applicably by taking contemplation of several aspects especially the gain. AMC helps to improve the performance of an antenna, hence enhancing the execution of wireless power transmission system of the rectenna. Wireless sensor network is one of the application in wireless power transmission system that applied the approach of energy harvesting, where it is considered to be a practical and deployable solution for today’s technology. Two designs of AMC had been proposed; a rectangular AMC using RO3003 substrate and a square AMC using RO3010 substrate. Simulation results show that the square AMC gives better performance through gain enhancement by 3.529 dB of a half-wave wire dipole antenna with an overall size of 122.45 mm x 122.45 mm
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