5,907 research outputs found

    Solar Obliquity Induced by Planet Nine

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    The six-degree obliquity of the sun suggests that either an asymmetry was present in the solar system's formation environment, or an external torque has misaligned the angular momentum vectors of the sun and the planets. However, the exact origin of this obliquity remains an open question. Batygin & Brown (2016) have recently shown that the physical alignment of distant Kuiper Belt orbits can be explained by a 5-20 Earth-mass planet on a distant, eccentric, and inclined orbit, with an approximate perihelion distance of ~250 AU. Using an analytic model for secular interactions between Planet Nine and the remaining giant planets, here we show that a planet with similar parameters can naturally generate the observed obliquity as well as the specific pole position of the sun's spin axis, from a nearly aligned initial state. Thus, Planet Nine offers a testable explanation for the otherwise mysterious spin-orbit misalignment of the solar system.Comment: 8 pages, 4 figures, manuscript #: AAS01477, submitted on June 24, 201

    Feasibility of a resonance-based Planet Nine search

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    It has been proposed that mean motion resonances (MMRs) between Planet Nine and distant objects of the scattered disk might inform the semimajor axis and instantaneous position of Planet Nine. Within the context of this hypothesis, the specific distribution of occupied MMRs largely determines the available constraints. Here we characterize the behavior of scattered Kuiper Belt objects arising in the presence of an eccentric Planet Nine (e9∈0.1e_9 \in 0.1, 0.70.7), focusing on relative sizes of populations occupying particular commensurabilities. Highlighting the challenge of predicting the exact MMR of a given object, we find that the majority of resonant test particles have period ratios with Planet Nine other than those of the form P9/P=N/1P_9/P=N/1, N/2N/2 (N∈Z+)(N \in \mathbb{Z}^+). Taking into account the updated prior distribution of MMRs outlined in this work, we find that the close spacing of high-order resonances, as well as chaotic transport, preclude resonance-based Planet Nine constraints from current observational data.Comment: 6 pages, 7 figure

    Comet Shoemaker‐Levy 9: No effect on the Io plasma torus

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    Observations of the Io plasma torus made before, during, and after the impact of Comet Shoemaker‐Levy 9 with Jupiter reveal no comet‐induced changes. Three weeks of high spectral‐resolution ground‐based visible spectroscopy show no changes larger than typical day‐to‐day variations in the torus densities, ion temperatures, or rotation velocities. Comparison with six months of identically obtained data from 1991 and 1992 also shows no differences

    Linking Research to Practice: FEWS NET and Its Use of Satellite Remote Sensing Data

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    The purpose of the Famine Early Warning Systems Network (FEWS NET) is to collaborate with international, regional and national partners to provide timely and rigorous early warning and vulnerability information on emerging and evolving food security issue

    Creating Successful Data Management Plans for your Grant Proposal

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    This presentation is part of a workshop about creating Data Management Plans (DMPs) using the DMPTool

    Evaluating the Use of Remote Sensing Data in the USAID Famine Early Warning Systems Network

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    The US Agency for International Development (USAID) s Famine Early Warning System Network (FEWS NET) provides monitoring and early warning support to decision makers responsible for responding to food insecurity emergencies on three continents. FEWS NET uses satellite remote sensing and ground observations of rainfall and vegetation in order to provide information on drought, floods and other extreme weather events to decision makers. Previous research has presented results from a professional review questionnaire with FEWS NET expert end-users whose focus was to elicit Earth observation requirements. The review provided FEWS NET operational requirements and assessed the usefulness of additional remote sensing data. Here we analyzed 1342 food security update reports from FEWS NET. The reports consider the biophysical, socioeconomic, and contextual influences on the food security in 17 countries in Africa from 2000-2009. The objective was to evaluate the use of remote sensing information in comparison with other important factors in the evaluation of food security crises. The results show that all 17 countries use rainfall information, agricultural production statistics, food prices and food access parameters in their analysis of food security problems. The reports display large scale patterns that are strongly related to history of the FEWS NET program in each country. We found that rainfall data was used 84% of the time, remote sensing of vegetation 28% of the time, and gridded crop models 10%, reflecting the length of use of each product in the regions. More investment is needed in training personnel on remote sensing products to improve use of data products throughout the FEWS NET system

    Likelihood of Asking for Help in Caregivers of Women With Substance Use or Co-Occurring Substance Use and Mental Disorders

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    Family members are important to the well-being of their relatives with substance use disorders or cooccurring substance use and mental disorders. Many caregivers experience high levels of burden, negatively impacting their capacity to provide support to their ill family member. The Andersen health care utilization model (Andersen & Newman, 1973, 2005) was used to identify the impact of predisposing, enabling, and need factors hypothesized to predict caregivers’ likelihood of asking for help and support with their caregiving role. The sample include 82 women recruited from outpatient or inpatient substance abuse treatment centers and 82 family caregivers nominated by these women. Findings showed that almost half of caregivers were unlikely to ask for help. Multiple regression analysis found that two need variables were statistically significant predictors of caregivers’ likelihood to ask for help. Caregivers who had higher subject burden (worry) and caregivers who provided more assistance with daily living were more likely to ask for help. It is suggested that case managers assess the amount of worried family caregivers’ experience because their worries may provide the motivation to ask for help or to participate in help when it is offered to them

    Starvation Resistance is Associated with Developmentally Specified Changes in Sleep, Feeding and Metabolic Rate

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    Food shortage represents a primary challenge to survival, and animals have adapted diverse developmental, physiological and behavioral strategies to survive when food becomes unavailable. Starvation resistance is strongly influenced by ecological and evolutionary history, yet the genetic basis for the evolution of starvation resistance remains poorly understood. The fruit fly Drosophila melanogaster provides a powerful model for leveraging experimental evolution to investigate traits associated with starvation resistance. While control populations only live a few days without food, selection for starvation resistance results in populations that can survive weeks. We have previously shown that selection for starvation resistance results in increased sleep and reduced feeding in adult flies. Here, we investigate the ontogeny of starvation resistance-associated behavioral and metabolic phenotypes in these experimentally selected flies. We found that selection for starvation resistance resulted in delayed development and a reduction in metabolic rate in larvae that persisted into adulthood, suggesting that these traits may allow for the accumulation of energy stores and an increase in body size within these selected populations. In addition, we found that larval sleep was largely unaffected by starvation selection and that feeding increased during the late larval stages, suggesting that experimental evolution for starvation resistance produces developmentally specified changes in behavioral regulation. Together, these findings reveal a critical role for development in the evolution of starvation resistance and indicate that selection can selectively influence behavior during defined developmental time points

    Speeding Ahead: Assessing Trends in Distance Librarian Services for Advanced Practice Nursing Programs

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    With the increasing popularity of distance education among universities and busy students, many Advanced Practice Nursing (APN) programs have shifted to become either online or hybrid programs. To meet the research and instruction needs of these students, some nursing librarians are using technology for virtual research and instruction. This study was designed to assess the extent to which nursing librarians in North America are providing virtual research and instruction services for APN students
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