1,699 research outputs found

    Charged-particle orbits near a magnetic null point

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    An approximate analytical expression is obtained for the orbits of a charged particle moving in a cusp magnetic field. The particle orbits pass close to or through a region of zero magnetic field before being reflected in regions where the magnetic field is strong. Comparison with numerically evaluated orbits shows that the analytical formula is surprisingly good and captures all the main features of the particle motion. A map describing the long-time behaviour of such orbits is obtained

    Postabortion contraception

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    The European Society of Contraception Expert Group on Abor tion identified as one of its priorities to disseminate up-to-date evidence-based information on postabortion contraception to healthcare providers. A concise communication was produced which summarises the latest research in an easy-to-read format suitable for busy clinicians. Information about individual methods is presented in boxes for ease of reference

    Self-assessment of success of early medical abortion using a self-performed urine pregnancy test.

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    Purpose: The European Society of Contraception Expert Group on Abortion identified as one of its priorities the need to disseminate up-to-date evidence-based information on the use of urine pregnancy tests by women for the self assessment of the success of early medical abortion (EMA). Methods and materials: A concise communication was produced which summarises the latest research in an easy-to-read format suitable for busy clinicians. Information about individual urinary pregnancy tests is presented in boxes for ease of reference. Results: Urinary pregnancy tests (low sensitivity, high sensitivity and multilevel) can be used in combination with signs and symptoms of pregnancy to exclude an ongoing pregnancy after EMA. Conclusion: Women are able to determine the success of early medical abortion (EMA) themselves using a combination of signs, symptoms and a urine pregnancy test. This simplifies EMA, expands the range of professionals able to provide EMA and most importantly gives women greater control over their bodies and treatment

    Johnson Space Center's Solar and Wind-Based Renewable Energy System

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    The NASA Johnson Space Center (JSC) in Houston, Texas has a Sustainability Partnership team that seeks ways for earth-based sustainability practices to also benefit space exploration research. A renewable energy gathering system was installed in 2007 at the JSC Child Care Center (CCC) which also offers a potential test bed for space exploration power generation and remote monitoring and control concepts. The system comprises: 1) several different types of photovoltaic panels (29 kW), 2) two wind-turbines (3.6 kW total), and 3) one roof-mounted solar thermal water heater and tank. A tie to the JSC local electrical grid was provided to accommodate excess power. The total first year electrical energy production was 53 megawatt-hours. A web-based real-time metering system collects and reports system performance and weather data. Improvements in areas of the CCC that were detected during subsequent energy analyses and some concepts for future efforts are also presented

    Structural and Functional Alterations in The Zona Fasciculata of The Rat Adrenal Cortex in Obstructive Jaundice

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    This study investigated the effect of experimentally-induced cholestasis in the rat on the structure and function of the zona fasciculata, the glucocorticoid secretory region of the adrenal cortex. Wistar-Furth rats (200-250g) were assigned to three groups: bile duct ligated (BDL), Sham operated (Sham) and unmodified normal control (NC). On day 14, serum bilirubin and liver histology were performed to confirm cholestasis in BDL animals together with basal 24 hour 17-hydroxycorti-costeroid excretion, adrenal histology and zona fasciculata ultrastructure in all experimental groups. Following this laparotomy, structural and functional studies were repeated on day 15 to evaluate the response of the gland to surgically induced stress. Basal 24 hr. 17-hydroxycorticoid steroid excretion was elevated in BDL animals (26.9 ±3.2 μ g/24 hr) with respect to Sham (10.4 ± 2.3) and NC groups (13.5 ± 3.2) (p <0.05). Adrenal histology and ultrastructural studies demonstrated excessive accumulation of vesicles laden with glucocorticoid biogenic precursors. Following surgical stress 24 hr 17 OH corticosteroid excretion increased in all groups: BDL (31.0 ± 3.0 μg/24 hr) vs Sham (15.6 ± 1.8) and NC (14.5 ± 2.4) Moderate alterations in zona fasciculata architecture were seen following surgery in all groups. Cholestasis induces overactivity of the zona fasciculata of the adrenal cortex, and may modify the normal metabolic responses to surgical and other stresses

    Mapping a nation’s landslides: a novel multi-stage methodology

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    Through combining new technologies and traditional mapping techniques, the British Geological Survey (BGS) has developed a novel, multi-stage methodology for landslide mapping. 3-D aerial photograph interpretation, variable-perspective 3-D topographic visualisation and field mapping with digital data capture are being used to map the UK’s landslides. The resulting ESRI ArcGIS polygons are published on BGS 1:50,000 geological maps and as digital data products. Data collected during mapping are also uploaded directly into the National Landslides Database maintaining a systematic, nationally-uniform landslide inventory. Repeat monitoring of selected landslides using terrestrial LIDAR and dGPS allows the database to be frequently updated and the proactive Landslide Response Team means that new landslide events can be mapped within days, if not hours, of their occurrence. The long-term aim is to apply this methodology throughout the UK, providing a wealth of data for scientific research and hazard assessment. This methodology is also suitable for application in an international context
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