3,256 research outputs found

    Ecosystem size predicts eco-morphological variability in a postglacial diversification

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    Identifying the processes by which new phenotypes and species emerge has been a long-standing effort in evolutionary biology. Young adaptive radiations provide a model to study patterns of morphological and ecological diversification in environmental context. Here, we use the recent radiation (ca. 12k years old) of the freshwater fish Arctic charr (Salvelinus alpinus) to identify abiotic and biotic environmental factors associated with adaptive morphological variation. Arctic charr are exceptionally diverse, and in postglacial lakes there is strong evidence of repeated parallel evolution of similar morphologies associated with foraging. We measured head depth (a trait reflecting general eco-morphology and foraging ecology) of 1,091 individuals across 30 lake populations to test whether fish morphological variation was associated with lake bathymetry and/or ecological parameters. Across populations, we found a significant relationship between the variation in head depth of the charr and abiotic environmental characteristics: positively with ecosystem size (i.e., lake volume, surface area, depth) and negatively with the amount of littoral zone. In addition, extremely robust-headed phenotypes tended to be associated with larger and deeper lakes. We identified no influence of co-existing biotic community on Arctic charr trophic morphology. This study evidences the role of the extrinsic environment as a facilitator of rapid eco-morphological diversification

    DEEP LEARNING MODEL UNCERTAINTY ESTIMATION USING MONTE CARLO DROPOUT TO IMPROVE UAV TARGET POSE PREDICTIONS

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    Target pose estimation is an important function of many relevant military applications including satellite rendezvous operations and directed energy weapons systems. This task is best left to deep learning (DL) models that can react more quickly than human operators; however, epistemic uncertainty exists in every model, which is manifested in the predictions it makes on inputs outside of its training distribution. This thesis develops a methodology to inform users whether a model’s output pose prediction should be trusted based on the model’s uncertainty. Model uncertainty was quantified using Monte Carlo dropout on in-distribution and out-of-distribution images of unmanned aerial vehicles (UAVs). Images of miniature UAVs taken using a laser beam testbed were passed through the model multiple times, each time producing a set of pose predictions due to the stochastic nature of dropout. The variances of the prediction sets were computed and were the proxy for model uncertainty. At inference, model error was measured as the geodesic distance between each ground truth pose label and the mean prediction in each set. Through experimentation, a correlation between model error and model uncertainty was identified and used to propose a threshold of variance above which the model was not to be trusted.Distribution Statement A. Approved for public release: Distribution is unlimited.Outstanding ThesisEnsign, United States NavyN/

    A controlled comparative investigation of rumination, worry, emotional inhibition and arousability in adults with nREM parasomnias, insomnia and good sleepers

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    Background: Little is known about the psychological characteristics of adults presenting with nREM parasomnias. Research indicates that a common factor associated with their onset is stress. Early studies suggest that adults experiencing such phenomena may be emotionally inhibited but no research has directly investigated this. Understanding of insomnia and its associated psychological factors is more developed with several studies finding a relationship with both worry and rumination. The role of somatic and especially cognitive arousal has also been emphasised. Methods: The present study aimed to investigate these psychological factors in adults who experience nREM parasomnias. 148 adults were recruited with the index group of interest being the nREM parasomnia (nREMp) group (n = 48), a parallel sleep disorder group of people with Insomnia (n = 50) and a control group of good sleepers (GS) (n = 50). The three groups were compared for differences on self-report measures of emotional inhibition, worry, rumination and arousal. Results: Compared with the GS group, significantly higher levels on all psychological variables were reported by the nREMp group and on all but rumination by the Insomnia group. The Insomnia group scored higher than the nREMp group on cognitive arousal with no other differences found between these two sleep disordered groups. Conclusions: Preliminary evidence is presented for the influence of psychological factors in nREM parasomnias. Further studies are required to replicate and extend these findings. There are, however, implications for the development and evaluation of psychological interventions which could prove a viable alternative treatment option for such clients in clinical settings

    When Two Worlds Meet: Academic Advisors’ Understanding of the Exploratory Student Experience at a Hispanic-Serving Institution

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    Academic advisors are essential to the college experience (Filson & Whittington, 2013). They serve as students’ higher education guides and translators in addition to being their direct link to the institution. Given the pivotal role they serve in helping students navigate the myriad transitions encountered throughout their college career, tapping into their vast experience with students, parents, and administration provided a unique point of view that would not otherwise be possible. The purpose of this study was to explore academic advisors\u27 understanding of the exploratory FTIC student experience at a Hispanic Serving Institution, which was chosen because of potential unique impacts on its non-white populations (Pascarella, 2006). In this qualitative study, 11 current and former academic advisors who worked with exploratory students at Florida International University were interviewed using a semi-structured format. Student interviews were used for triangulation purposes. Once interviews were transcribed, thematic analysis was used to analyze the data for common themes. The study found that participants saw a need to destigmatize the exploration process because it negatively impacts how students feel about being labeled exploratory. According to the advisors, many students are ashamed of identifying as exploratory. Advisors were vocal about their frustration with external pressures (e.g., excess credit, metrics, and department policies) affecting students’ progress and by students’ expression of the unfairness of being limited to 30 credits when that is not enough time to go through the exploration process. Moreover, this study revealed a lack of structured opportunities for exploratory students to meet other exploratory students. The advisors acknowledged that student-to-student connections are important to the undergraduate experience and can contribute to feeling a sense of belonging. The findings of this study can also be used to develop training and professional development opportunities for academic advisors to enhance their knowledge of this complex student population, help students develop a positive exploratory identity, and produce resources that can improve the advising experience for exploratory students

    Medical humanities as expressive of Western culture

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    In this paper we articulate a growing awareness within the field of the ways in which medical humanities could be deemed expressive of Western cultural values. The authors suggest that medical humanities is culturally limited by a pedagogical and scholarly emphasis on Western cultural artefacts, as well as a tendency to enact an uncritical reliance upon foundational concepts (such as ‘patient’ and ‘experience’) within Western medicine. Both these tendencies within the field, we suggest, are underpinned by a humanistic emphasis on appreciative or receptive encounters with ‘difference’ among patients that may unwittingly contribute to the marginalisation of some patients and healthcare workers. While cultural difference should be acknowledged as a central preoccupation of medical humanities, we argue that the discipline must continue to expand its scholarly and critical engagements with processes of Othering in biomedicine. We suggest that such improvements are necessary in order to reflect the cultural diversification of medical humanities students, and the geographical expansion of the discipline within non-Western and/or non-Anglophone locations

    Controlling Soil Pox in Sweet Potatoes

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    You can control sweet potato soil pox by making your soil slightly acid with sulfur applications. Remember that certain other crops don\u27t do well on acid soil nor is this practical for soils that already have been heavily limed

    Some Historical Features of Potato Stem Necrosis Associated With Actinomyces Scabies

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    Certain varieties of potato (Solanum tuberosum L.) are extremely susceptible to the common scab disease caused by Actinomyces scabies (Thaxt.) GĂŒssow, whereas the tubers of others are very resistant. The scab organism is also capable of parasitizing the stems, causing severe necrosis which may result in premature death of the plant. Varieties known to be resistant to tuber scab show considerable resistance to stem necrosis, whereas those susceptible to tuber scab are likewise susceptible to scab on the stems

    Second Life: Community and Society as a Focus for Marketing Approaches

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    Virtual worlds such as Second Life have recently gained increased visibility from businesses seeking to market products “in-world” to virtual world participants. However, without understanding the sociological orientation of virtual participants, the effectiveness of marketing approaches in virtual worlds may be limited. This study utilizes a Delphi approach to determine the sociological orientation of a panel of Second Life participants, with the goal of constructing a theoretical model which can be used for testing the effectiveness of various marketing approaches in virtual worlds

    Consistency for 0-1 Programming

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    Concepts of consistency have long played a key role in constraint programming but never developed in integer programming (IP). Consistency nonetheless plays a role in IP as well. For example, cutting planes can reduce backtracking by achieving various forms of consistency as well as by tightening the linear programming (LP) relaxation. We introduce a type of consistency that is particularly suited for 0-1 programming and develop the associated theory. We define a 0-1 constraint set as LP-consistent when any partial assignment that is consistent with its linear programming relaxation is consistent with the original 0-1 constraint set. We prove basic properties of LP-consistency, including its relationship with Chvatal-Gomory cuts and the integer hull. We show that a weak form of LP-consistency can reduce or eliminate backtracking in a way analogous to k-consistency but is easier to achieve. In so doing, we identify a class of valid inequalities that can be more effective than traditional cutting planes at cutting off infeasible 0-1 partial assignments

    Structure of 10N in 9C+p resonance scattering

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    The structure of exotic nucleus 10N was studied using 9C+p resonance scattering. Two L=0 resonances were found to be the lowest states in 10N. The ground state of 10N is unbound with respect to proton decay by 2.2(2) or 1.9(2) MeV depending on the 2- or 1- spin-parity assignment, and the first excited state is unbound by 2.8(2) MeV.Comment: 6 pages, 4 figures, 1 table, submitted to Phys. Lett.
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