724 research outputs found

    Effect of Aqueous and Ethanolic Extracts of Tribulus terrestris, Phoenix dactylifera and Nasturtium officinale Mixture on Some Reproductive Parameters in Male Mice

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    The present investigation was conducted to evaluate the effect of the crude extracts mixture of three plants (Tribulus terrestris, Phoenix dactylifera and Nasturtium officinale) on semen quality,sex hormones and reproductive performance of mature male mice. A group of 25 male mice given 150mg/kg/day of the powder of the plants mixture with the food for four weeks and another three groups of 25 animals each given intraperitoneal injection from each of the aqueous and ethanolic extracts with a doses 75, 150, and 300mg/kg/day for two weeks. A remarkable increase in sperm concentration and motility with a decreased abnormal morphology was obtained in the experimental groups. A significant increase in hormones level were recognized in most groups. The results of mating untreated females with treated males of the four experimental groups revealed a decreased gestation period and an increased litter size. The results showed a dose dependent pattern of activity and the effect of the extracts were enhanced with increasing the dose level. The ethanolic extract being the more effective extract in all parameters

    Biomimetic Based EEG Learning for Robotics Complex Grasping and Dexterous Manipulation

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    There have been tremendous efforts to understand the biological nature of human grasping, in such a way that it can be learned and copied to prosthesis–robotics and dextrous grasping applications. Several biomimetic methods and techniques have been adopted, hence applied to analytically comprehend ways human performs grasping to duplicate human knowledge. A major topic for further study, is related to decoding the resulting EEG brainwaves during motorizing of fingers and moving parts. To accomplish this, there are a number of phases that are performed, including recording, pre-processing, filtration, and understanding of the waves. However, there are two important phases that have received substantial research attentions. The classification and decoding, of such massive and complex brain waves, as they are two important steps towards understanding patterns during grasping. In this respect, the fundamental objective of this research is to demonstrate how to employ advanced pattern recognition methods, like fuzzy c-mean clustering for understanding resulting EEG brain waves, in such a way to control a prosthesis or robotic hand, while relying sets of detected EEG brainwaves. There are a number of decoding and classification methods and techniques, however we shall look into fuzzy based clustering blended with principle component analysis (PAC) technique to help for the decoding mechanism. EEG brainwaves during a grasping and manipulation have been used for this analysis. This involves, movement of almost five fingers during a grasping defined task. The study has found that, it is not a straight forward task to decode all human fingers motions, as due to the complexity of grasping tasks. However, the adopted analysis was able to classify and identify the different narrowly performed and related fundamental events during a simple grasping task

    Risk in global infrastructure project financing

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.Includes bibliographical references (leaves 73-74).Project financing has been the main financing structure of public-private ventures in infrastructure projects. Investors face several risks when going into these projects. These risks are even higher when the project is located in a foreign country. This thesis examines the risk exposure of investors and more specifically of lenders when financing foreign infrastructure projects. Basically these risks can be divided into three main categories: financial risks; political risks; and project's performance risks. The first category includes risks that have to do with the financial aspect of the investment such as interest rate risk, currency transfer and inconvertibility risks, and mainly currency devaluation risk. Political risks are country specific risks that could result from political, legal or regulatory actions that are unfavorable for the project's interest. The third category of risks includes the project's specific risks. These could vary from construction delays or cost overrun, to quality of performance of the project, to market risk... The first step in risk management is to identify and quantify the exposure to each of these risks. This is relatively easy when dealing with financial risks, however much more difficult in the two other categories. Hedging financial risks is done by the appropriate use of financial derivatives coupled with internal hedging strategies. Political risk hedging is mainly achieved by either introducing "strong sleeping partners" or by buying insurance policies. Finally performance risks could be easily prevented by adopting appropriate contractual agreements. Based on the results of a survey conducted with the major US commercial banks, lenders account for most of these risks. And when involved in international infrastructure financing they do hedge part of their risk exposure using the same hedging techniques discussed previously.by Mahdi Mattar.S.M

    Caracterización espectral de Quillaja saponaria (Mol.)

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    Revista oficial de la Asociación Española de Teledetección[EN] This paper presents a spectral reflectance characterization of the specie Quillaja saponaria (Mol.), endemic tree of Chile and valued by society due to its provision of several ecosystem services that gives to society and also for its high concentration of saponins in cortex widely used in the pharmacological industry. For spectral characterization a foliar spectral signatures protocol was designed which included standardized instrumental and environmental parameters. The spectral response of different individuals was measured to evaluate the spectral behaviour and degree of variability within species in the visible and near infrared ranges (VNIR; 400-990 nm) with two hyperspectral sensors (ASD HH and camera PDF-65-V10E). The resulting spectral signatures obtained with ASD HH showed a variation less than 5% of reflectance in VNIR and lesser than that in the transition zone from red to near infrared (red-edge; 680-730 nm). Additionally, two distinctive spectral features were detected for the specie, the first is related to a fast increase of reflectance in bands 450-480 nm and the second, to a marked decrease in the 920-970 nm range associated with water absorption features. At branch level, these distinctive features are maintained but with a smaller magnitude of reflectance, which could indicate that they are useful characteristic spectral patterns that can eventually be used for monitoring the physical health state of the specie using remote sensing. On the other hand, we used a PDF-65 camera for study the plant vigour from different health states (healthy, ill, died) with spectral vegetation index. The Plant Senescence Reflectance Index detected stress on leaves, and Triangular Vegetation Index allows for a gradually characterization of every state. This work provides the first spectral reference for one of the most important sclerophyll species of Chile.[ES] En este trabajo se presenta una caracterización de la reflectancia espectral de Quillaja saponaria (Mol.), especie endémica de Chile y principalmente valorada por los servicios ecosistémicos que brinda a la sociedad así como su elevada concentración de saponinas en la corteza, utilizada como insumo en la industria farmacéutica. Para la caracterización espectral se diseñó un protocolo de adquisición de firmas espectrales foliares, controlando pará-metros instrumentales y ambientales. Se evaluó el comportamiento espectral y el grado de variabilidad de la especie en el rango del visible e infrarrojo cercano (VNIR; 400-990 nm) con dos sensores hiperespectrales (ASD HH y cámara PDF-65-V10E). Las firmas espectrales obtenidas con el ASD HH mostraron una variación inferior al 5% de reflectancia en el VNIR y en menor medida en la zona de transición del visible al infrarrojo cercano (red-edge; 680-730 nm). Además, se detectaron dos rasgos espectrales distintivos de la especie, el primero se relaciona con un incremento rápido de la reflectancia en los 450-480 nm y el segundo, un decrecimiento entre los 920-970 nm relacionado con las bandas de absorción de agua. De hecho, al medir la reflectancia de un conjunto de ramas apiladas, éstos rasgos perduran pero con una menor magnitud, indicando un patrón espectral característico y eventualmente utilizable en campañas de monitoreo del estado físico y sanitario de la especie mediante teledetección. Usando la cámara PDF-65 se estudió el vigor de las hojas bajo diferentes condiciones sanitarias (sana, enferma, muerta) a través de los índices espectrales de vegetación. Entre los resultados, el índice PSRI (Plant Senescence Reflectance Index) detecta sectores de bajo vigor fotosintético y el TVI (Triangular Vegetation Index) permite una caracterización gradual de cada condición. Este trabajo presenta la primera referencia espectral para una de las especies de bosque esclerófilo más importante de Chile.Este trabajo fue financiado por el proyecto Fondecyt 1140319 “Vegetation Knowledge-based Indicators for Urban Sustainable Planning” de CONICYT Chile. Los autores también agradecen a AGSEN y a SPECIM por contribuir con la imagen obtenida con la cámara hiperespectral PDF-65-V10E.Acuña, T.; Mattar, C.; Hernández, HJ. (2016). Spectral characterization of Quillaja saponaria (Mol.). Revista de Teledetección. (47):65-73. https://doi.org/10.4995/raet.2016.6488SWORD65734

    Microporosity evolution and destruction in the Jurassic Arab D reservoir, Qatar

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    Core samples were collected from three wells, one onshore and two offshore, from Qatar’s Upper Jurassic Arab D reservoir. The samples were subjected to multiproxy petrographic and chemical analyses to identify their micro- and nanoporosity types and understand their evolution and destruction. Based on the petrographic and petrophysical properties of studied rocks, the Arab D succession was divided into seven rock types. Primary microporosity includes intergranular and interplanar, while secondary types include vuggy, intercrystalline, moldic, dissolution, pyrite displacement, microfracture, and microbial boring. Primary micropores were found mainly between the micrite grains in the lime mudstone facies, between the grains or the plates of clay minerals. Secondary micropores result from open and closed diagenetic systems. The open diagenetic system led to the development of dissolution and moldic micropores, while the closed system created pyrite displacement and boring porosity. Mechanical stress due to crystal growth or displacement generated microfractures. Micropores were destroyed either by cementation, clay minerals growth, dolomitization, or microbial pustular overgrowth. Microporosity was important in quantity and varied in nature in the mud-supported rocks. They are similar to macropores in grain-supported sediments but of less importance. The complex lithology of the studied rocks has significantly influenced the development and destruction of the porosity system of the Arab Formation.The chemical analyses were conducted at the Central Laboratory Unit, Qatar University. We are grateful for their continuous support and professionalism. We thank the management and technicians of the Gas Processing Center (GPC) and the Center for Advanced Materials (CAM), Qatar University for the XRF and XRD analyses. Thanks to Thomas Seers and Ibrahim Almaghrabi (Texas A&M, Doha Campus) for the thin section preparation. David Marioni read the original manuscript and made many valuable amendments. This research is supported by Qatar Foundation through Grant # NPRP11S-0109-180241

    Understanding the relationship between pet owners and their companion animals as a key context for antimicrobial resistance-related behaviours: an Interpretative Phenomenological Analysis

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    Objectives: Drivers of antimicrobial resistance (AMR) are diffuse and complex including a range of interspecies behaviours between pet owners and their animals. We employed interpretative phenomenological analysis (IPA) to explore the relationship between pet owners and their companion animals in relation to AMR.Design: Cross sectional, qualitative study.Methods: Semi-structured interviews were conducted with twenty-three British pet owners, transcribed verbatim and subjected to Interpretative Phenomenological Analysis (IPA).Results: Three, inter-related Superordinate themes are presented 1) ‘They’re my fur babies’: unconditional love and anthropomorphism; 2) ‘They share everything with you’: affection and transmission behaviours; and 3) ‘We would err on the side of caution’: decision making and antibiotic use’.Conclusions: Affectionate behaviors between companion animals and their owners pose a risk for AMR transmission but they are so deeply treasured that they are unlikely to be amenable to change. In contrast, the promotion of appropriate antibiotic stewardship for pet owners and vets may offer a viable pathway for intervention development, benefitting from synergies with other interventions that target prescribers

    Super-radiant light scattering from trapped Bose Einstein condensates

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    We propose a new formulation for atomic side mode dynamics from super-radiant light scattering of trapped atoms. A detailed analysis of the recently observed super-radiant light scattering from trapped bose gases [S. Inouye {\it et al.}, Science {\bf 285}, 571 (1999)] is presented. We find that scattered light intensity can exhibit both oscillatory and exponential growth behaviors depending on densities, pump pulse characteristics, temperatures, and geometric shapes of trapped gas samples. The total photon scattering rate as well as the accompanied matter wave amplification depends explicitly on atom number fluctuations in the condensate. Our formulation allows for natural and transparent interpretations of subtle features in the MIT data, and provides numerical simulations in good agreement with all aspects of the experimental observations.Comment: 24 pages,16 figures, submitted to Phys.Rev.

    Distinct Haptic Cues Do Not Reduce Interference when Learning to Reach in Multiple Force Fields

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    Background: Previous studies of learning to adapt reaching movements in the presence of novel forces show that learning multiple force fields is prone to interference. Recently it has been suggested that force field learning may reflect learning to manipulate a novel object. Within this theoretical framework, interference in force field learning may be the result of static tactile or haptic cues associated with grasp, which fail to indicate changing dynamic conditions. The idea that different haptic cues (e.g. those associated with different grasped objects) signal motor requirements and promote the learning and retention of multiple motor skills has previously been unexplored in the context of force field learning. Methodology/Principle Findings: The present study tested the possibility that interference can be reduced when two different force fields are associated with differently shaped objects grasped in the hand. Human subjects were instructed to guide a cursor to targets while grasping a robotic manipulandum, which applied two opposing velocity-dependent curl fields to the hand. For one group of subjects the manipulandum was fitted with two different handles, one for each force field. No attenuation in interference was observed in these subjects relative to controls who used the same handle for both force fields. Conclusions/Significance: These results suggest that in the context of the present learning paradigm, haptic cues on their own are not sufficient to reduce interference and promote learning multiple force fields

    Features of dengue and chikungunya infections of colombian children under 24 months of age admitted to the emergency department

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    We aimed to assess clinical and laboratory differences between dengue and chikungunya in children <24 months of age in a comparative study. We collected retrospective clinical and laboratory data confirmed by NS1/IgM for dengue for 19 months (1 January 2013 to 17 August 2014). Prospective data for chikungunya confirmed by real-time polymerase chain reaction were collected for 4 months (22 September 2014-14 December 2014). Sensitivity and specificity [with 95% confidence interval (CI)] were reported for each disease diagnosis. A platelet count <150 000 cells/ml at emergency admission best characterized dengue, with a sensitivity of 67% (95% CI, 53-79) and specificity of 95% (95% CI, 82-99). The algorithm developed with classification and regression tree analysis showed a sensitivity of 93% (95% CI, 68-100) and specificity of 38% (95% CI, 9-76) to diagnose dengue. Our study provides potential differential characteristics between chikungunya and dengue in young children, especially low platelet counts. © The Author [2017].Universidad Nacional de Colombia, UN Johns Hopkins University1Departamento de Epidemiologia, Hospital Infantil Napoleón Franco Pareja—La Casa del Niño, Cartagena, Colombia 2Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia 3Departamento de Epidemiologia, Faculdade de Saúde Publica, Universidade de São Paulo, São Paulo, Brazil 4Facultad de Ingenería, Universidad Tecnológica de Bolívar, Cartagena, Colombia 5Facultad Ciencias Básicas y Biomédicas, Universidad Simón Bolívar, Barranquilla, Colombia 6Facultad de Medicina, Universidad de Cartagena, Cartagena, Colombia 7Instituto de Investigaciones Biologicas del Tropico, Universidad de Córdoba, Montería, Colombia 8Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA Correspondence: Angel Paternina-Caicedo, Hospital Infantil Napoleón Franco Pareja—La Casa del Niño, Bruselas Transversal 36 N. 36-33, Cartagena, Bolívar, Colombia. Tel: +1-412-3267809. E-mail or
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