472 research outputs found

    Effect of light polarization on plasma distribution and filament formation

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    We show that, for 200 fs light pulses at 790 nm, the formation of filaments is strongly affected by the laser light polarization . Filamentation does not exist for a pure circularly polarized light, propagating in vacuum before focusing in air, while there is no difference for focusing the light in air or vacuum for linearly polarized light.Comment: 4pages 2 figure

    Guiding neutral atoms around curves with lithographically patterned current-carrying wires

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    Laser-cooled neutral atoms from a low-velocity atomic source are guided via a magnetic field generated between two parallel wires on a glass substrate. The atoms bend around three curves, each with a 15-cm radius of curvature, while traveling along a 10-cm-long track. A maximum flux of 2*10^6 atoms/sec is achieved with a current density of 3*10^4 A/cm^2 in the 100x100-micrometer-cross-section wires. The kinetic energy of the guided atoms in one transverse dimension is measured to be 42 microKelvin.Comment: 9 page

    Letter from Julian B. Grow, Executive Vice President of the Queens Transit Corps., to Geraldine Ferraro

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    Congratulatory letter from Julian B. Grow, Executive Vice President of the Queens Transit Corps., to Geraldine Ferraro. Includes data entry sheet.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_new_york/1276/thumbnail.jp

    Proximity to Sports Facilities and Sports Participation for Adolescents in Germany

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    Objectives - To assess the relationship between proximity to specific sports facilities and participation in the corresponding sports activities for adolescents in Germany. Methods - A sample of 1,768 adolescents aged 11–17 years old and living in 161 German communities was examined. Distances to the nearest sports facilities were calculated as an indicator of proximity to sports facilities using Geographic Information Systems (GIS). Participation in specific leisure-time sports activities in sports clubs was assessed using a self-report questionnaire and individual-level socio-demographic variables were derived from a parent questionnaire. Community-level socio-demographics as covariates were selected from the INKAR database, in particular from indicators and maps on land development. Logistic regression analyses were conducted to examine associations between proximity to the nearest sports facilities and participation in the corresponding sports activities. Results - The logisitic regression analyses showed that girls residing longer distances from the nearest gym were less likely to engage in indoor sports activities; a significant interaction between distances to gyms and level of urbanization was identified. Decomposition of the interaction term showed that for adolescent girls living in rural areas participation in indoor sports activities was positively associated with gym proximity. Proximity to tennis courts and indoor pools was not associated with participation in tennis or water sports, respectively. Conclusions - Improved proximity to gyms is likely to be more important for female adolescents living in rural areas

    Two-stage evolution of mantle peridotites from the Stalemate Fracture Zone, northwestern Pacific

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    This paper reports the results of a mineralogical study of 14 mantle peridotite samples dredged in 2009 from the eastern slope of the northwestern segment of the Stalemate Ridge in the northwestern Pacific during cruise SO201-KALMAR Leg 1b of the R/V Sonne. The sample collection included four serpentinized and silicified dunites and ten variably serpentinized lherzolites. The compositions of primary minerals (clinopyroxene, orthopyroxene, and spinel) change systematically from the lherzolites to dunites. Spinel from the lherzolites shows higher Mg# and lower Cr# values (0.65-0.68 and 0.26-0.33, respectively) compared with spinel from the dunites (Mg# = 0.56-0.64 and Cr# = 0.38-0.43). Clinopyroxene from the lherzolites is less magnesian (Mg# = 91.7-92.4) than clinopyroxene from dunite sample DR37-3 (Mg# = 93.7). Based on the obtained data, it was concluded that the lherzolites of the Stalemate Fracture Zone were derived by 10-12% near-fractional melting of a DMM-type depleted mantle reservoir beneath the Kula-Pacific spreading center. The dunites were produced by interaction of residual lherzolites with sodium- and titaniumrich melt and are probably fragments of a network of dunite channels in the shallow mantle. The moderately depleted composition of minerals clearly distinguishes the lherzolites from the strongly depleted peridotites of the East Pacific Rise and indicates the existence of slow-spreading mid-ocean ridges in the Pacific Ocean during the Cretaceous-Paleogene

    A tale of two towns: A comparative study exploring the possibilities and pitfalls of social capital among people seeking recovery from substance misuse

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    Background: Social capital has become an influential concept in debating and understanding the modern world. Within the drug and alcohol sector, the concept of ‘recovery capital’ has gained traction with researchers suggesting that people who have access to such capital are better placed to overcome their substance use-related problems than those who do not (Cloud and Granfield, 2008), leading to requests for interventions that focus on building social capital networks (Neale & Stevenson, 2015). While accepting that the concept of social capital has enormous potential for addressing the problems associated with drug use, this paper also considers its ‘dark side’. Methods: Data were drawn from semi-structured interviews with 180 participants including 135 people who use drugs and 45 people who formerly used drugs. Results: High levels of trust, acquired through the establishment of dense social networks, are required to initiate recovery. However, these ‘strong bonds’ may also lead to the emergence of what is perceived by others as an exclusive social network that limits membership to those who qualify and abide by the ‘rules’ of the recovery community, particularly around continuous abstinence. Conclusions: Depending on the nature of the networks and the types of links participants have into them being socially connected can both inhibit and encourage recovery. Therefore, the successful application of social capital within the drugs and alcohol field requires a consideration of not only the presence or absence of social connections but their nature, the value they produce, and the social contexts within which they are developed

    Does toxic defence in Nycticebus spp. relate to ectoparasites? The lethal effects of slow loris venom on arthropods

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    a b s t r a c t The venom produced by slow lorises (Nycticebus spp.) is toxic both intra-and inter-specifically. In this study we assessed the ecoparasite repellent properties of their venom. We tested venom from two Indonesian slow loris species: Nycticebus javanicus and Nycticebus coucang. Arthropods directly exposed to brachial gland secretions mixed with saliva from both species were immediately impaired or exhibited reduced activity (76%), and often died as a result (61%). We found no significant difference in the result of 60-min trials between N. coucang and N. javanicus [X 2 (1, n ¼ 140) ¼ 2.110, p ¼ 0.3482]. We found evidence that the degree of lethality of the venom varies according to the arthropod taxa to which it is exposed. While most maggots (84%) were initially impaired from the venom after 10 min, maggots died after a 1 h trial 42% of the time. In contrast, at the end of 1 h trial, spiders died 78% of the time. For all arthropods, the average time to death from exposure was less than 25 min (M ¼ 24.40, SD ¼ 22.60). Ectoparasites including ticks, members of the arachnid order, are known to transmit pathogens to hosts and may be an intended target of the toxic secretions. Our results suggest that one function of slow loris venom is to repel parasites that affect their fitness, and that their topical anointing behaviour may be an adaptive response to ectoparasites

    Write, draw, show, and tell: a child-centred dual methodology to explore perceptions of out-of-school physical activity

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    Background Research to increase children’s physical activity and inform intervention design has, to date, largely underrepresented children’s voices. Further, research has been limited to singular qualitative methods that overlook children’s varied linguistic ability and interaction preference. The aim of this study was to use a novel combination of qualitative techniques to explore children’s current views, experiences and perceptions of out-of-school physical activity as well as offering formative opinion about future intervention design. Methods Write, draw, show and tell (WDST) groups were conducted with 35 children aged 10–11 years from 7 primary schools. Data were analysed through a deductive and inductive process, firstly using the Youth Physical Activity Promotion Model as a thematic framework, and then inductively to enable emergent themes to be further explored. Pen profiles were constructed representing key emergent themes. Results The WDST combination of qualitative techniques generated complimentary interconnected data which both confirmed and uncovered new insights into factors relevant to children’s out-of-school physical activity. Physical activity was most frequently associated with organised sports. Fun, enjoyment, competence, and physical activity provision were all important predictors of children’s out-of-school physical activity. Paradoxically, parents served as both significant enablers (i.e. encouragement) and barriers (i.e. restricting participation) to physical activity participation. Some of these key findings would have otherwise remained hidden when compared to more traditional singular methods based approaches. Conclusions Parents are in a unique position to promote health promoting behaviours serving as role models, physical activity gatekeepers and choice architects. Given the strong socialising effect parents have on children’s physical activity, family-based physical activity intervention may offer a promising alternative compared to traditional school-based approaches. Parents' qualitative input is important to supplement children’s voices and inform future family-based intervention design. The WDST method developed here is an inclusive, interactive and child-centred methodology which facilitates the exploration of a wide range of topics and enhances data credibility
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