3,520 research outputs found

    Comparing legislative mechanisms for SEA screening and decision-making: Austrian and Australian experiences

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    Austrian and Australian approaches to strategic environmental assessment (SEA) are compared with particular emphasis upon the legal basis for the initial phase of agreement/screening and the final stage of SEA decision-making and implementation. In Austrian SEA, screening is compulsory and the outcome leads only to recommendations, meaning that the SEA results have to be considered, but are not binding for the approval decision. In Australia engagement in SEA is largely voluntary but the process results in legally binding conditions of approval that can be applied to relevant actions arising from an assessed policy, plan or programme; the incentive for proponents to participate voluntarily is that subsequent project level activities may be exempt from further assessment processes. Compulsory SEA in Australia also provides a legally certain outcome, a factor of benefit to proponents. Examples of SEAs are provided to demonstrate the operation of the respective stages in the two countries. In Austria compulsory screening results in a lot of energy being spent avoiding triggering a full SEA. Although Australian proponents have been somewhat cautious in volunteering for SEA of their activities, there are signs that this is changing. We argue that the regulatory framework characteristics are a key determinant of the behaviour of proponents and the competent authority in practice and subsequently of SEA potential and outcomes. Consideration of the construct of the regulatory framework for SEA screening and decision-making provides a useful point of reflection for practitioners attempting to understand the effectiveness of SEA processes in a given jurisdiction

    Simulation models for autonomous rendezvous and capture

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    Autonomous rendezvous and capture (AR&C) is a critical space technology with significant application to a variety of missions. Martin Marietta Astronautics Group (MMAG) has been developing AR&C technical capability in support of several recent NASA contracts. The use of AR&C for the Mars Rover/Sample Return (MRSR) mission was studied through a contract with JSC. Incorporation of AR&C in the Space Transportation Vehicle (STV) lunar mission was studied through a contract with MSFC. The MMAG has also been developing AR&C simulation capability under independent research and development studies. Simulation development was driven by two goals: comprehensive software simulation of the autonomous rendezvous and capture mission from launch to final capture; and integration of the overall software and hardware simulation to support an AR&C flight demonstration. This presentation will highlight the AR&C software simulation tools and analyze results from their application to the STV lunar mission. Plans for an integrated software and hardware simulation will also be summarized

    Properties of HxTaS2

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    The preparation of Hx TaS2 (0 \u3c x \u3c 0.87) is described. The compounds are only marginally stable at room temperature, slowly evolving H2S and H2 (and possibly Hp in air). Magnetic susceptibility data show that a low temperature transformation in 2H ... TaS2 (at so•K) is suppressed with the addition of hydrogen, and· at the same time the superconducting transition temperature T c rises from 0.8 to ~4.2•K at x = 0.11. Heat capacity measurements near this concentration show the superconductivity to be a bulk effect. Finally, by correlation of this data with susceptibility and T c measurements in other intercalation compounds, we suggest that the rise of T c (at low electron transfer) is due to suppression of the low temperature transformation and not due to an excitonic mechanism of superconductivity

    Towards magnetic slowing of atoms and molecules

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    We outline a method to slow paramagnetic atoms or molecules using pulsed magnetic fields. We also discuss the possibility of producing trapped particles by adiabatic deceleration of a magnetic trap. We present numerical simulation results for the slowing and trapping of molecular oxygen

    Cumulative and Differential Effects of Early Child Care and Middle Childhood Out-of-School Time on Adolescent Functioning.

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    Effects associated with early child care and out-of-school time (OST) during middle childhood were examined in a large sample of U.S. adolescents (N = 958). Both higher quality early child care AND more epochs of organized activities (afterschool programs and extracurricular activities) during middle childhood were linked to higher academic achievement at age 15. Differential associations were found in the behavioral domain. Higher quality early child care was associated with fewer externalizing problems, whereas more hours of early child care was linked to greater impulsivity. More epochs of organized activities was associated with greater social confidence. Relations between early child care and adolescent outcomes were not mediated or moderated by OST arrangements in middle childhood, consistent with independent, additive relations of these nonfamilial settings

    Constrained Willmore Surfaces

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    Constrained Willmore surfaces are conformal immersions of Riemann surfaces that are critical points of the Willmore energy W=H2W=\int H^2 under compactly supported infinitesimal conformal variations. Examples include all constant mean curvature surfaces in space forms. In this paper we investigate more generally the critical points of arbitrary geometric functionals on the space of immersions under the constraint that the admissible variations infinitesimally preserve the conformal structure. Besides constrained Willmore surfaces we discuss in some detail examples of constrained minimal and volume critical surfaces, the critical points of the area and enclosed volume functional under the conformal constraint.Comment: 17 pages, 8 figures; v2: Hopf tori added as an example, minor changes in presentation, numbering changed; v3: new abstract and appendix, several changes in presentatio

    Phase separation transition in liquids and polymers induced by electric field gradients

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    Spatially uniform electric fields have been used to induce instabilities in liquids and polymers, and to orient and deform ordered phases of block-copolymers. Here we discuss the demixing phase transition occurring in liquid mixtures when they are subject to spatially nonuniform fields. Above the critical value of potential, a phase-separation transition occurs, and two coexisting phases appear separated by a sharp interface. Analytical and numerical composition profiles are given, and the interface location as a function of charge or voltage is found. The possible influence of demixing on the stability of suspensions and on inter-colloid interaction is discussed.Comment: 7 pages, 3 figures. Special issue of the J. Phys. Soc. Ja

    A comparison between endoscopic ultrasound-guided rendezvous and percutaneous biliary drainage after failed ERCP for malignant distal biliary obstruction

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    Background and study Aims: Selective biliary cannulation is unsuccessful in 5 % to 10 % of patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) for malignant distal biliary obstruction (MDBO). Percutaneous biliary drainage (PBD) has been the gold standard, but endoscopic ultrasound guided rendezvous (EUSr) have been increasingly used for biliary decompression in this patient population. Our aim was to compare the initial success rate, long-term efficacy, and safety of PBD and EUSr in relieving MDBO after failed ERC Patients and methods: A retrospective study involving 50 consecutive patients who had an initial failed ERCP for MDBO. Twenty-five patients undergoing EUSr between 2008 – 2014 were compared to 25 patients who underwent PBD immediately prior to the introduction of EUSr at our center (2002 – 2008). Comparisons were made between the two groups with regard to technical success, duration of hospital stay and adverse event rates after biliary decompression. Results: The mean age at presentation was 66.5 (± 12.6 years), 28 patients (54.9 %) were female. The etiology of MDBO was pancreaticobiliary malignancy in 44 (88 %) and metastatic disease in 6 (12 %) cases. Biliary drainage was technically successful by EUSr in 19 (76 %) cases and by PBD in 25 (100 %) (P = 0.002). Median length of hospital stay after initial drainage was 1 day in the EUSr group vs 5 days in PBD group (P = 0.02). Repeat biliary intervention was required for 4 patients in the EUSr group and 15 in the PBD group (P = 0.001). Conclusions: Initial technical success with EUSr was significantly lower than with PBD, however when EUSr was successful, patients had a significantly shorter post-procedure hospital stay and required fewer follow-up biliary interventions. Meeting presentations: Annual Digestive Diseases Week 201
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