2,698 research outputs found

    Perceptions and correlates of peer-victimization and bullying

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    The experiences of peer-victimization and bullying are often treated empirically as though they are conceptually indistinct. Both involve repeated aggression,but definitions of bullying additionally emphasize the importance of aggressor intent and imbalance of power between the aggressor and the victim (Olweus, 1978; Whitney & Smith, 1993). The present study aimed to examine the extent to which peer-victimization and bullying are empirically similar. The sample comprised 1,429 pupils (50.2% male) aged between 8 and 13 years attending mainstream Scottish schools. Self-report questionnaire assessing peer-victimization and bullying, copingstrategy use (WCCL: Hunter, 2000), situational appraisal and depressive symptomatology (Birleson, 1981). Almost one-third (30.7%) of pupils reported experiencing peer-victimization, and of these 38.1% (11.7% of whole sample) were categorized as victims of bullying. Victims of bullying perceived higher levels of threat and lower levels of perceived control. They also reported using more Wishful Thinking and Social Support coping strategies, but did not differ on Problem Focused coping. Bullied pupils also reported higher levels of depressive symptomatology. Peer-victimization and bullying appear to be qualitatively different experiences for children and adolescents, with bullying being the more serious phenomenon

    A latest Cretaceous to earliest Paleogene dinoflagellate cyst zonation of Antarctica, and implications for phytoprovincialism in the high southern latitudes

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    The thickest uppermost Cretaceous to lowermost Paleogene (Maastrichtian to Danian) sedimentary succession in the world is exposed on southern Seymour Island (65° South) in the James Ross Basin, Antarctic Peninsula. This fossiliferous shallow marine sequence, which spans the Cretaceous–Paleogene boundary, has allowed a high-resolution analysis of well-preserved marine palynomorphs. Previous correlation of Cretaceous–Paleogene marine palynomorph assemblages in the south polar region relied on dinoflagellate cyst biozonations from New Zealand and southern Australia. The age model of the southern Seymour Island succession is refined and placed within the stratigraphical context of the mid to high southern palaeolatitudes. Quantitative palynological analysis of a new 1102 m continuous stratigraphical section comprising the uppermost Snow Hill Island Formation and the López de Bertodano Formation (Marambio Group) across southern Seymour Island was undertaken. We propose the first formal late Maastrichtian to early Danian dinoflagellate cyst zonation scheme for the Antarctic based on this exceptional succession. Two new late Maastrichtian zones, including three subzones, and one new early Danian zone are defined. The oldest beds correlate well with the late Maastrichtian of New Zealand. In a wider context, a new South Polar Province based on Maastrichtian to Danian dinoflagellate cysts is proposed, which excludes most southern South American marine palynofloras. This interpretation is supported by models of ocean currents around Antarctica and implies an unrestricted oceanic connection across Antarctica between southern South America and the Tasman Sea

    Improving photoelectron counting and particle identification in scintillation detectors with Bayesian techniques

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    Many current and future dark matter and neutrino detectors are designed to measure scintillation light with a large array of photomultiplier tubes (PMTs). The energy resolution and particle identification capabilities of these detectors depend in part on the ability to accurately identify individual photoelectrons in PMT waveforms despite large variability in pulse amplitudes and pulse pileup. We describe a Bayesian technique that can identify the times of individual photoelectrons in a sampled PMT waveform without deconvolution, even when pileup is present. To demonstrate the technique, we apply it to the general problem of particle identification in single-phase liquid argon dark matter detectors. Using the output of the Bayesian photoelectron counting algorithm described in this paper, we construct several test statistics for rejection of backgrounds for dark matter searches in argon. Compared to simpler methods based on either observed charge or peak finding, the photoelectron counting technique improves both energy resolution and particle identification of low energy events in calibration data from the DEAP-1 detector and simulation of the larger MiniCLEAN dark matter detector

    NASA Centers and Universities Collaborate in Annual Smallsat Technology Partnerships

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    The Small Spacecraft Technology program within the NASA Space Technology Mission Directorate sponsors the Smallsat Technology Partnerships (STP) initiative. The STP initiative awards cooperative agreements between NASA centers and university teams for technology development efforts that advance the capabilities of small spacecraft to achieve NASA mission objectives in unique and more affordable ways. NASA’s announcement to return humans to the Moon by 2024 raises new opportunities for Smallsats to contribute to missions in cislunar space, though technical challenges are to be overcome to establish their value in this environment. Precursor missions utilizing small spacecraft will blaze the trail for lunar exploration, establishing infrastructure such as communication and navigation networks, and performing assembly and repair services for larger structures and human habitats. To achieve these goals, certain novel Smallsat technologies will need to be developed and demonstrated. The 2020 STP solicitation sought proposals for specific technologies to enable these lunar missions. For the 2020 STP cycle, NASA selected nine university teams to mature new systems and capabilities in the laboratory, and in some cases, demonstrate in suborbital or orbital spaceflights. This paper describes the STP portfolio, past and present efforts, and the nine partnerships selected

    Asperciones de permetrina microencapsulada para el control de la garrapata sureña del ganado, Boophilus microplus (Aeari:Ixodidae), infestando novillas lecheras Holstein en Santa Cruz, Islas Vírgenes Americanas

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    The effectiveness of two acaricides was evaluated for control of populations of the southern cattle tick, Boophilus microplus on dairy cattle in St. Croix, U.S. Virgin Islands. Two different concentrations of a microencapsulated (ME) formulation of permethrin (0.05% and 0.10% ai) and one concentration of coumaphos emulsifiable concentrate (EC) (0.117% ai) were sprayed on Holstein heifers that had a natural infestation of ticks. The length of residual activity of EC coumaphos and ME permethrin at 0.05% (ai) was at least four days, and for ME permethrin at 0.10% ai at least seven days.There was no apparent increase in the residual activity period of ME permethrin in comparison to that in field trials of other formulations of permethrin against B. microplus. Percentage control for the three treatment groups from days 4 through 21 was ME permethrin (0.05% ai) 96%; ME permethrin (0.10% ai), 97%; coumaphos, 98.3%. There were no significant differences among the treatment groups (F = 2.21, df = 2,17, P> 0.10). This research confirms the usefulness of permethrin as an alternative to coumaphos for control of B. microplus populations on cattle.Se evaluaron dos acaricidas por su efectividad para controlar las poblaciones de la garrapata sureña Boophilus microplus en ganado lechero en Santa Cruz, Islas Virgenes Americanas. Se asperjaron dos concentraciones diferentes de una formulación microencapsulada (ME) de permetrína (0.05 y 0.10% ia) y una concentración de coumaphos concentrado emulsificable (0,117% ia) sobre novillas Holstein que presentaban una infestación natural de garrapatas. La actividad residual del coumaphos y la permetrina ME (0.05% ia) fue por lo menos de cuatro días y la de permetrina ME (0.10% ia) fue de por lo menos siete días. El largo del periodo residual de la permetrina ME sobre el Boophilus microplus no aumentó en comparación con experimentos de campo con otras formulaciones de permetrinas. El porcentaje de control para los tres tratamientos desde los días 4 al 21 fue: permetrina ME (0.05% ia), 96%; permetrina ME (0,10% ia), 97%; coumaphos, 98.3%. Las diferencias entre las medias de los diferentes tratamientos no fueron significativas (F= 2.21; g.l. = 2,17, P> 0.10). Esta investigación confirma que la permetrina es una alternativa para el control de B. microplus en poblaciones de ganado

    Adolescent bullying and sleep difficulties

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    This study evaluated whether adolescents who report having been bullied, being bullies, or report both being a bully and being bullied experience more sleep difficulties than children uninvolved in bullying. The study drew upon cognitive theories of insomnia, investigating whether the extent to which young people report worrying about bullying can moderate associations between victimization and sleep difficulties. Participants were 5420 adolescents who completed a self-report questionnaire. Pure Victims (OR = 1.72: 95% CI [1.07 – 2.75]), Pure Bullies (OR = 1.80: 95% CI [1.16 – 2.81]), and Bully-Victims (OR = 2.90: 95% CI [1.17 – 4.92]) were all more likely to experience sleep difficulties when compared to uninvolved young people. The extent to which young people reported worrying about being bullied did not moderate the links between victimization and sleep difficulties. In this way, bullying is clearly related to sleep difficulties among adolescents but the conceptual reach of the cognitive model of insomnia in this domain is questioned

    Air and Soil Temperature Readings, Growing Degree Days, and Chilling Hours Recorded in Two Wiregrass Tunnel Houses Located in East Central Alabama

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    The study examined air and soil temperature readings, growing degree days, and chilling hours recorded in two Wiregrass tunnel houses during the 2018-2019 season. The monthly average ambient temperature, was 15OF warmer inside the Tunnel House (75/60OF) during the Cool/Cold months, and 17OF warmer inside (90/73OF) during the Warm/Hot seasons of 2018 and 2019. Growing Degree Days heat unit (HU) accumulations were higher inside than outside 4,154 vs. 3,153 HU for the Cool/Cold months and 5,134 vs. 4,800 HU for the Warm/Hot months. Chilling hour accumulations were lower inside the tunnel houses than outside the tunnel houses, 601vs. 671 hr. Utilizing the temperature data from this study, a planting guide consisting of a Cool/Cold (September-February) season and Warm/Hot (March-August) season was developed for a list of crops which producers could plant. The results of this study provides information for growers to better plan their crop choices and planting schedules

    Integrated Propulsion/Vehicle System Structurally Optimized

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    Ongoing research and testing are essential in the development of air-breathing hypersonic propulsion technology, and this year some positive advancement was made at the NASA Glenn Research Center. Recent work performed for GTX, a rocket-based combined-cycle, single-stage-to-orbit concept, included structural assessments of both the engine and flight vehicle. In the development of air-breathing engine technology, it is impractical to design and optimize components apart from the fully integrated system because tradeoffs must be made between performance and structural capability. Efforts were made to control the flight trajectory, for example, to minimize the aerodynamic heating effects. Structural optimization was applied to evaluate concept feasibility and was instrumental in the determination of the gross liftoff weight of the integrated system. Achieving low Earth orbit with even a small payload requires an aggressive approach to weight minimization through the use of lightweight, oxidation-resistant composite materials. Assessing the integrated system involved investigating the flight trajectory to determine where the critical load events occur in flight and then generating the corresponding environment at each of these events. Structural evaluation requires the mapping of the critical flight loads to finite element models, including the combined effects of aerodynamic, inertial, combustion, and other loads. NASA s APAS code was used to generate aerodynamic pressure and temperature profiles at each critical event. The radiation equilibrium surface temperatures from APAS were used to predict temperatures through the thickness. Heat transfer solutions using NASA's MINIVER code and the SINDA code (Cullimore & Ring Technologies, Littleton, CO) were calculated at selective points external to the integrated vehicle system and then extrapolated over the entire exposed surface. FORTRAN codes were written to expedite the finite element mapping of the aerodynamic heating effects for the internal structure
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