209 research outputs found

    NASA/NBS (National Aeronautics and Space Administration/National Bureau of Standards) standard reference model for telerobot control system architecture (NASREM)

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    The document describes the NASA Standard Reference Model (NASREM) Architecture for the Space Station Telerobot Control System. It defines the functional requirements and high level specifications of the control system for the NASA space Station document for the functional specification, and a guideline for the development of the control system architecture, of the 10C Flight Telerobot Servicer. The NASREM telerobot control system architecture defines a set of standard modules and interfaces which facilitates software design, development, validation, and test, and make possible the integration of telerobotics software from a wide variety of sources. Standard interfaces also provide the software hooks necessary to incrementally upgrade future Flight Telerobot Systems as new capabilities develop in computer science, robotics, and autonomous system control

    Experimental research activity on additive manufacturing of microwave passive waveguide components

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    All metal passive waveguide components are key building-blocks of several RF systems used for telecommunications, navigation, imaging, radio-astronomy, and cosmology. The accurate manufacture of these devices in Additive Manufacturing (AM) technologies can open the way to a high integration level of microwave functionalities with a significant cost and mass reduction. In the paper, after an introduction on the most common AM technologies with particular detail on selective laser melting (SLM) and stereo-lithography apparatus (SLA) processes, the results on the on-going research activity are discussed. Measured performances are reported for AM prototypes of Ku/K/Ka-band rectangular and circular waveguide lines, microwave filters and a smooth wall horn

    Characteristic Mode Analysis of Multi-Octave Asymmetric Dipoles

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    This paper discusses the impedance and front-to-back ratio performance of asymmetric dipoles. These parameters are very important when the antennas are placed over a conductive ground plane and should operate over multi-octave frequency bands. The operation of these antennas is usually described relying on analogies with more classical structures such as symmetric dipoles and tapered slot antennas. To provide a solid theoretical background to this intuition, this work presents the application of characteristic mode analysis to multi-octave dipole antennas. Firstly, a brief review of the main characteristic mode content is presented. Then, characteristic mode analysis is applied to three antenna concepts to emphasize how their geometry impacts on the relevant figures of merit. This allows to draw some conclusions on the achievable performance by different designs

    Maternal dietary fatty acid intake during pregnancy and the risk of preclinical and clinical type 1 diabetes in the offspring.

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    The aim of the present study was to examine the associations between the maternal intake of fatty acids during pregnancy and the risk of preclinical and clinical type 1 diabetes in the offspring. The study included 4887 children with human leucocyte antigen (HLA)-conferred type 1 diabetes susceptibility born during the years 1997-2004 from the Finnish Type 1 Diabetes Prediction and Prevention Study. Maternal diet was assessed with a validated FFQ. The offspring were observed at 3- to 12-month intervals for the appearance of type 1 diabetes-associated autoantibodies and development of clinical type 1 diabetes (average follow-up period: 4·6 years (range 0·5-11·5 years)). Altogether, 240 children developed preclinical type 1 diabetes and 112 children developed clinical type 1 diabetes. Piecewise linear log-hazard survival model and Cox proportional-hazards regression were used for statistical analyses. The maternal intake of palmitic acid (hazard ratio (HR) 0·82, 95 % CI 0·67, 0·99) and high consumption of cheese during pregnancy (highest quarter v. intermediate half HR 0·52, 95 % CI 0·31, 0·87) were associated with a decreased risk of clinical type 1 diabetes. The consumption of sour milk products (HR 1·14, 95 % CI 1·02, 1·28), intake of protein from sour milk (HR 1·15, 95 % CI 1·02, 1·29) and intake of fat from fresh milk (HR 1·43, 95 % CI 1·04, 1·96) were associated with an increased risk of preclinical type 1 diabetes, and the intake of low-fat margarines (HR 0·67, 95 % CI 0·49, 0·92) was associated with a decreased risk. No conclusive associations between maternal fatty acid intake or food consumption during pregnancy and the development of type 1 diabetes in the offspring were detected

    Rescue leadless pacemaker implantation in a pacemaker-dependent patient with congenital heart disease and no alternative routes for pacing

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    Congenital heart disease patients are considered a unique group of patients regarding their high risk of conduction abnormalities, whether de novo or surgically induced, and the challenges in both implantation and management of device related complications. We present a case of a pacemaker-dependent patient with congenital heart disease who experienced complications of both previous epicardial and transvenous pacing which rendered her a non-suitable candidate of both routes

    Maternal Risk of Breeding Failure Remained Low throughout the Demographic Transitions in Fertility and Age at First Reproduction in Finland

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    Radical declines in fertility and postponement of first reproduction during the recent human demographic transitions have posed a challenge to interpreting human behaviour in evolutionary terms. This challenge has stemmed from insufficient evolutionary insight into individual reproductive decision-making and the rarity of datasets recording individual long-term reproductive success throughout the transitions. We use such data from about 2,000 Finnish mothers (first births: 1880s to 1970s) to show that changes in the maternal risk of breeding failure (no offspring raised to adulthood) underlay shifts in both fertility and first reproduction. With steady improvements in offspring survival, the expected fertility required to satisfy a low risk of breeding failure became lower and observed maternal fertility subsequently declined through an earlier age at last reproduction. Postponement of the age at first reproduction began when this risk approximated zero–even for mothers starting reproduction late. Interestingly, despite vastly differing fertility rates at different stages of the transitions, the number of offspring successfully raised to breeding per mother remained relatively constant over the period. Our results stress the importance of assessing the long-term success of reproductive strategies by including measures of offspring quality and suggest that avoidance of breeding failure may explain several key features of recent life-history shifts in industrialized societies

    Altruism and sacrifice : mafia free gift giving in south Italy

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    As a social phenomenon that torments modern states, mafia receives considerable political and legal attention. The term mafia itself is often directly related to criminality and violence. Thus far violence has been employed as an analytical construct that could explain compliance with the mafia ethos. Nevertheless this schema fails to take into consideration possible discourses that make mafia tolerable. Drawing on fieldwork conducted in Reggio Calabria, South Italy, this paper explores distinctive mafia notions of giving and charity. Mafia free gifts, albeit rare, are paradoxical in the sense that through elaborate speech registers both the donor and the recipient debase the very act of gift-giving so as not to be bound in relations of reciprocity and obligation. These mafia gifts, which have so far escaped anthropological attention, are conceptualised as tropes of worldly imagining aspiring to non-worldly discourses. Status, umiltà, duty and sacrifice frame free gifting as accorded to the overt religious rhetoric of mafia hierarchy. In this paper I argue that a) free gifting embraces a series of complex non-violent discourses which relate closely to religious duty and altruism but work alongside capitalist systems b) in principal these gifts do not bind people, yet are imbued with the potential of a relation.PostprintPeer reviewe

    Cork : properties, capabilities and applications

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    Cork is a natural, renewable, sustainable raw material that has been used for many centuries. As a result of this very long term interest, the scientific literature on cork is extensive. The present review focuses on the chemical composition, physical and mechanical properties of cork and on its products and sub-products. The substantial efforts to fully characterise cork, as well as new developments and evolving research, are reviewed, beginning with its histology, growth and morphology (at macro- and microscales). The chemical structure is analysed in detail, covering both the materials that form the wall structure and the low molecular weight, extractable components. The unique properties of cork are discussed and correlated with current knowledge on morphology and chemical structure. Finally, the important industrial applications of cork are reviewed, in the context of research to provide cork with novel, high added-value applications

    Environmental Enrichment Preceding Early Adulthood Methylphenidate Treatment Leads to Long Term Increase of Corticosterone and Testosterone in the Rat

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    Attention-deficit/hyperactivity disorder (ADD/ADHD) has been emerging as a world-wide psychiatric disorder. There appears to be an increasing rate of stimulant drug abuse, specifically methylphenidate (MPH) which is the most common treatment for ADHD, among individuals who do not meet the criteria for ADHD and particularly for cognitive enhancement among university students. However, the long term effects of exposure to MPH are unknown. Thus, in light of a developmental approach in humans, we aimed to test the effects of adolescence exposure to enriched environment (EE) followed by MPH administration during early adulthood, on reactions to stress in adulthood. Specifically, at approximate adolescence [post natal days (PND) 30–60] rats were reared in EE and were treated with MPH during early adulthood (PND 60–90). Adult (PND 90–92) rats were exposed to mild stress and starting at PND 110, the behavioral and endocrine effects of the combined drug and environmental conditions were assessed. Following adolescence EE, long term exposure to MPH led to decreased locomotor activity and increased sucrose preference. EE had a beneficial effect on PPI (attentive abilities), which was impaired by long term exposure to MPH. Finally, the interaction between EE and, exposure to MPH led to long-term elevated corticosterone and testosterone levels. In view of the marked increase in MPH consumption over the past decade, vigilance is crucial in order to prevent potential drug abuse and its long term detrimental consequences
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