1,578 research outputs found

    Tabanidae of Mexico, Central America and the West Indies

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    http://deepblue.lib.umich.edu/bitstream/2027.42/56601/1/OP162.pd

    Co-operative experiments made by the Ohio Agricultural Students' Union in 1896

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    Caption title.Mode of access: Internet

    Opaque Service Virtualisation: A Practical Tool for Emulating Endpoint Systems

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    Large enterprise software systems make many complex interactions with other services in their environment. Developing and testing for production-like conditions is therefore a very challenging task. Current approaches include emulation of dependent services using either explicit modelling or record-and-replay approaches. Models require deep knowledge of the target services while record-and-replay is limited in accuracy. Both face developmental and scaling issues. We present a new technique that improves the accuracy of record-and-replay approaches, without requiring prior knowledge of the service protocols. The approach uses Multiple Sequence Alignment to derive message prototypes from recorded system interactions and a scheme to match incoming request messages against prototypes to generate response messages. We use a modified Needleman-Wunsch algorithm for distance calculation during message matching. Our approach has shown greater than 99% accuracy for four evaluated enterprise system messaging protocols. The approach has been successfully integrated into the CA Service Virtualization commercial product to complement its existing techniques.Comment: In Proceedings of the 38th International Conference on Software Engineering Companion (pp. 202-211). arXiv admin note: text overlap with arXiv:1510.0142

    Asteroid 1986 DA: Radar evidence for a metallic composition

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    Radar observations of the near-Earth asteroid 1986 DA were carried out at the Arecibo Observatory in April 1986, two months after its discovery. Radar results are consistent with the hypothesis that 1986 HA is a piece of NiFe metal derived from the interior of a much larger object that melted, differentiated, cooled and subsequently was disrupted in a catastrophic collision. This 2-km asteroid might be (or have been part of) the parent body of some iron meteorites. Or 1986 DA might share the parentage and/or part of the dynamical history of some meteorites without ever having contributed any of its own ejecta to our meteorite sample. Analysis of the samples returned from 1986 DA might ultimately involve economic considerations. Meteoritic metal is mostly iron with about 8 percent nickel, but also contains substantial concentrations of precious and strategic metals, including approx. 1 ppm of gold and approx. 10 ppm of platinum group elements. If these abundances apply to 1986 DA, it contains some 10(exp 16) g of iron, 10 (exp 15) g of nickel, 10(exp 11) g of platinum group metals, and 10(exp 10) g of gold

    Clinical Toxicologic Studies on Freon R FE 1301

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    After conducting appropriate animal tests to ascertain safe levels, human subjects were exposed to concentrations of from 1.25% to 16.9% V/V of FE 1301. Assessment of judgement, alertness and neuromuscular skill indicated minimal but discernible effects at the lowest concentration in some individuals. At 10% V/V all subjects were effected. Stage I anesthesia occurred at 15% and Stage II would probably have occurred at 20%. A marked cardiac arrhythmia resulted in one subject exposed to 14%. There was complete recovery in all subjects within 20 minutes after exposure. No liver dysfunction occurred. The critical level for effective fire control is near 6%. This level would be acceptable on clinical toxicologic criteria

    On the possible existence of short-period g-mode instabilities powered by nuclear burning shells in post-AGB H-deficient (PG1159-type) stars

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    We present a pulsational stability analysis of hot post-AGB H-deficient pre-white dwarf stars with active He-burning shells. The stellar models employed are state-of-the-art equilibrium structures representative of PG1159 stars derived from the complete evolution of the progenitor stars. On the basis of fully nonadiabatic pulsation computations, we confirmed theoretical evidence for the existence of a separate PG1159 instability strip in the logTefflogg\log T_{\rm eff} - \log g diagram characterized by short-period gg-modes excited by the ϵ\epsilon-mechanism. This instability strip partially overlaps the already known GW Vir instability strip of intermediate/long period gg-modes destabilized by the classical κ\kappa-mechanism acting on the partial ionization of C and/or O in the envelope of PG1159 stars. We found that PG1159 stars characterized by thick He-rich envelopes and located inside this overlapping region could exhibit both short and intermediate/long periods simultaneously. we study the particular case of VV 47, a pulsating planetary nebula nucleus that has been reported to exhibit a series of unusually short pulsation periods. We found that the long periods exhibited by VV 47 can be readily explained by the classical κ\kappa-mechanism, while the observed short-period branch below 300\approx 300 s could correspond to modes triggered by the He-burning shell through the ϵ\epsilon-mechanism, although more observational work is needed to confirm the reality of these short-period modes. Were the existence of short-period gg-modes in this star convincingly confirmed by future observations, VV 47 could be the first known pulsating star in which both the κ\kappa-mechanism and the ϵ\epsilon-mechanism of mode driving are simultaneously operating.Comment: 9 pages, 5 figures, 2 tables. To be published in The Astrophysical Journa

    The Wilderness Expedition: An effective life course intervention to improve young peoples well-being and connectedness to nature

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    It is well understood that wilderness expeditions improve well-being; however, there is little supporting quantitative data. The aim of this study was to measure the impact of wilderness expeditions on self-esteem (SE) and connectedness to nature (CN) and assess whether benefits varied according to participant and expedition characteristics. SE and CN were assessed pre– and post–wilderness expeditions in 130 adolescents using Rosenberg’s SE scale and the state CN scale. Two-way ANOVA revealed significant increases in SE and CN (p < .001) as a result of single expeditions. There was also an interaction effect of expedition and gender on SE (p < .05). Males had a higher SE at the start but female SE increased most. Linear regression revealed that living environment, gender, and the length and location of the expedition did not contribute to changes in SE and CN. Regular contact with natural environments will improve adolescent well-being, with the largest improvements in females

    The elevated Curie temperature and half-metallicity in the ferromagnetic semiconductor Lax_{x}Eu1x_{1-x}O

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    Here we study the effect of La doping in EuO thin films using SQUID magnetometry, muon spin rotation (μ\muSR), polarized neutron reflectivity (PNR), and density functional theory (DFT). The μ\muSR data shows that the La0.15_{0.15}Eu0.85_{0.85}O is homogeneously magnetically ordered up to its elevated TCT_{\rm C}. It is concluded that bound magnetic polaron behavior does not explain the increase in TCT_{\rm C} and an RKKY-like interaction is consistent with the μ\muSR data. The estimation of the magnetic moment by DFT simulations concurs with the results obtained by PNR, showing a reduction of the magnetic moment per Lax_{x}Eu1x_{1-x}O for increasing lanthanum doping. This reduction of the magnetic moment is explained by the reduction of the number of Eu-4ff electrons present in all the magnetic interactions in EuO films. Finally, we show that an upwards shift of the Fermi energy with La or Gd doping gives rise to half-metallicity for doping levels as high as 3.2 %.Comment: 7 pages, 11 figure

    “It’s like my life but more, and better!” - Playing with the Cathaby Shark Girls: MMORPGs, young people and fantasy-based social play

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    This article is available open access through the publisher’s website at the link below. Copyright @ 2011 A B Academic Publishers.Digital technology has opened up a range of new on-line leisure spaces for young people. Despite their popularity, on-line games and Massive Multiplayer Online Role Playing Games in particular are still a comparatively under-researched area in the fields of both Education and more broadly Youth Studies. Drawing on a Five year ethnographic study, this paper considers the ways that young people use the virtual spaces offered by MMORPGs. This paper suggests that MMORPGs represent significant arenas within which young people act out a range of social narratives through gaming. It argues that MMORPG have become important fantasy spaces which offer young people possibilities to engage in what were formally material practices. Although this form of play is grounded in the everyday it also extends material practices and offers new and unique forms of symbolic experimentation, thus I argue that game-play narratives cannot be divorced from the everyday lives of their participants

    Self-focused pulse propagation is mediated by spatiotemporal optical vortices

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    We show that the dynamics of high-intensity laser pulses undergoing self-focused propagation in a nonlinear medium can be understood in terms of the topological constraints imposed by the formation and evolution of spatiotemporal optical vortices (STOVs). STOVs are born from point phase defects on the sides of the pulse nucleated by spatiotemporal phase shear. These defects grow into closed loops of spatiotemporal vorticity that initially exclude the pulse propagation axis, but then reconnect to form a pair of toroidal vortex rings that wrap around it. STOVs constrain the intrapulse flow of electromagnetic energy, controlling the focusing-defocusing cycles and pulse splitting inherent to nonlinear pulse propagation. We illustrate this in two widely studied but very different regimes, relativistic self-focusing in plasma and non-relativistic self-focusing in gas, demonstrating that STOVs mediate nonlinear propagation irrespective of the detailed physics
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