75 research outputs found

    Improving the ability of image sensors to detect faint stars and moving objects using image deconvolution techniques

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    In this paper we show how the techniques of image deconvolution can increase the ability of image sensors as, for example, CCD imagers, to detect faint stars or faint orbital objects (small satellites and space debris). In the case of faint stars, we show that this benefit is equivalent to double the quantum efficiency of the used image sensor or to increase the effective telescope aperture by more than 30% without decreasing the astrometric precision or introducing artificial bias. In the case of orbital objects, the deconvolution technique can double the signal-to-noise ratio of the image, which helps to discover and control dangerous objects as space debris or lost satellites. The benefits obtained using CCD detectors can be extrapolated to any kind of image sensorsPeer ReviewedPostprint (published version

    Wavelet-based Image deconvolution for Wide Field CCD Imagery

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    We show how a wavelet-based image adaptive deconvolution algorithm can provide significant improvements in the analysis of wide-field CCD images. To illustrate it, we apply our deconvolution protocol to a set of images from a Baker-Nunn telescope. This f/1 instrument has an outstanding field of view of 4.4°x4.4° with high optical quality offering unique properties to study our deconvolution process and results. In particular, we obtain an estimated gain in limiting magnitude of ΔR∼0.6 mag and in limiting resolution of Δρ∼3.9 arcsec. These results increase the number of targets and the efficiency of the underlying scientific project

    U.S. Physician-Scientist Workforce in the 21st Century: Recommendations to Attract and Sustain the Pipeline

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    The U.S. physician-scientist (PS) workforce is invaluable to the nation's biomedical research effort. It is through biomedical research that certain diseases have been eliminated, cures for others have been discovered, and medical procedures and therapies that save lives have been developed. Yet, the U.S. PS workforce has both declined and aged over the last several years. The resulting decreased inflow and outflow to the PS pipeline renders the system vulnerable to collapsing suddenly as the senior workforce retires. In November 2015, the Alliance for Academic Internal Medicine hosted a consensus conference on the PS workforce to address issues impacting academic medical schools, with input from early-career PSs based on their individual experiences and concerns. One of the goals of the conference was to identify current impediments in attracting and supporting PSs and to develop a new set of recommendations for sustaining the PS workforce in 2016 and beyond. This Perspective reports on the opportunities and factors identified at the conference and presents five recommendations designed to increase entry into the PS pipeline and nine recommendations designed to decrease attrition from the PS workflow

    Association between antidementia medication use and mortality in people diagnosed with dementia with Lewy bodies in the UK: A retrospective cohort study.

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    BACKGROUND: Dementia with Lewy bodies (DLBs) is a common cause of dementia but has higher mortality than Alzheimer's disease (AD). The reasons for this are unclear, but antidementia drugs (including acetylcholinesterase inhibitors [AChEIs] and memantine) symptomatically benefit people with DLB and might improve outcomes. We investigated whether AChEIs and/or memantine were associated with reduced hospital admissions and mortality. METHODS AND FINDINGS: We performed a retrospective cohort study of those diagnosed with DLB between 1 January 2005 and 31 December 2019, using data from electronic clinical records of secondary care mental health services in Cambridgeshire and Peterborough NHS Foundation Trust (CPFT), United Kingdom (catchment area population approximately 0.86 million), as well as linked records from national Hospital Episode Statistics (HES) data. Eligible patients were those who started AChEIs or memantine within 3 months of their diagnosis (cases) and those who never used AChEIs or memantine (controls). Outcomes included admission, length of stay, and mortality. Cox proportional hazard and linear regression models were used. Of 592 patients with DLB, 219 never took AChEIs or memantine, 100 took AChEIs only, and 273 took both AChEIs and memantine. The cohorts were followed up for an average of 896 days, 981 days, and 1,004 days, respectively. There were no significant differences in the cohorts' baseline characteristics, except for socioeconomic status that was lower in patients who never took AChEIs or memantine (χ2 = 23.34, P = 0.003). After controlling for confounding by sociodemographic factors (age, sex, marital status, ethnicity, socioeconomic status), antipsychotic use, antidepressant use, cognitive status, physical comorbidity, anticholinergic burden, and global health performance, compared with patients who never took AChEIs or memantine, patients taking AChEIs only or taking both had a significantly lower risk of death (adjusted hazard ratio (HR) = 0.67, 95% CI = 0.48 to 0.93, p = 0.02; adjusted HR = 0.64, 95% CI = 0.50 to 0.83, P = 0.001, respectively). Those taking AChEIs or both AChEIs and memantine had significantly shorter periods of unplanned hospital admission for physical disorders (adjusted coefficient -13.48, 95% CI = [-26.87, -0.09], P = 0.049; adjusted coefficient -14.21, 95% CI = [-24.58, -3.85], P = 0.007, respectively), but no difference in length of stay for planned admissions for physical disorders, or for admissions for mental health disorders. No significant additional associations of memantine on admission, length of stay, and mortality were found (all P > 0.05). The main limitation was that this was a naturalistic study and possible confounds cannot be fully controlled, and there may be selection bias resulting from nonrandom prescription behaviour in clinical practice. However, we mimicked the intention-to-treat design of clinical trials, and the majority of baseline characters were balanced between cohorts. In addition, our series of sensitivity analyses confirmed the consistency of our results. CONCLUSION: In this study, we observed that use of AChEIs with or without memantine in DLB was associated with shorter duration of hospital admissions and decreased risk of mortality. Although our study was naturalistic, it supports further the use of AChEIs in DLB

    The genomes of two key bumblebee species with primitive eusocial organization

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    Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation

    Atheisms and the purification of faith

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    Philosophers of religion have distinguished between ‘negative’ and ‘positive’ atheism. This article considers further conceptions of atheism, especially the idea that atheism can facilitate a faith in God purified of idolatrous assumptions. After introducing Bultmann’s contention that a ‘conscious atheist’ can find something transcendent in the world, this contention is interpreted through reflection on Ricoeur’s claim that the atheisms of Nietzsche and Freud serve to mediate a transition to a purified faith – a faith involving heightened receptivity to agapeic love. The troubling question of what differentiates atheism from belief in God is then discussed in the light of Simone Weil’s meditations on God’s secret presence

    Crowdsourcing Controls: A Review and Research Agenda for Crowdsourcing Controls Used for Macro-tasks

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    Crowdsourcing—the employment of ad hoc online labor to perform various tasks—has become a popular outsourcing vehicle. Our current approach to crowdsourcing—focusing on micro-tasks—fails to leverage the potential of crowds to tackle more complex problems. To leverage crowds to tackle more complex macro tasks requires a better comprehension of crowdsourcing controls. Crowdsourcing controls are mechanisms used to align crowd workers’ actions with predefined standards to achieve a set of goals and objectives. Unfortunately, we know very little about the topic of crowdsourcing controls directed at accomplishing complex macro tasks. To address issues associated with crowdsourcing controls formacro-tasks, this chapter has several objectives. First, it presents and discusses the literature on control theory. Second, this chapter presents a scoping literature review of crowdsourcing controls. Finally, the chapter identifies gaps and puts forth a research agenda to address these shortcomings. The research agenda focuses on understanding how to employ the controls needed to perform macro-tasking in crowds and the implications for crowdsourcing system designers.National Science Foundation grant CHS-1617820Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150493/1/Robert 2019 Preprint Chapter 3.pdfDescription of Robert 2019 Preprint Chapter 3.pdf : PrePrint Versio

    The Eat Smart Study: A randomised controlled trial of a reduced carbohydrate versus a low fat diet for weight loss in obese adolescents

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    Background Despite the recognition of obesity in young people as a key health issue, there is limited evidence to inform health professionals regarding the most appropriate treatment options. The Eat Smart study aims to contribute to the knowledge base of effective dietary strategies for the clinical management of the obese adolescent and examine the cardiometablic effects of a reduced carbohydrate diet versus a low fat diet. Methods and design Eat Smart is a randomised controlled trial and aims to recruit 100 adolescents over a 2½ year period. Families will be invited to participate following referral by their health professional who has recommended weight management. Participants will be overweight as defined by a body mass index (BMI) greater than the 90th percentile, using CDC 2000 growth charts. An accredited 6-week psychological life skills program ‘FRIENDS for Life’, which is designed to provide behaviour change and coping skills will be undertaken prior to volunteers being randomised to group. The intervention arms include a structured reduced carbohydrate or a structured low fat dietary program based on an individualised energy prescription. The intervention will involve a series of dietetic appointments over 24 weeks. The control group will commence the dietary program of their choice after a 12 week period. Outcome measures will be assessed at baseline, week 12 and week 24. The primary outcome measure will be change in BMI z-score. A range of secondary outcome measures including body composition, lipid fractions, inflammatory markers, social and psychological measures will be measured. Discussion The chronic and difficult nature of treating the obese adolescent is increasingly recognised by clinicians and has highlighted the need for research aimed at providing effective intervention strategies, particularly for use in the tertiary setting. A structured reduced carbohydrate approach may provide a dietary pattern that some families will find more sustainable and effective than the conventional low fat dietary approach currently advocated. This study aims to investigate the acceptability and effectiveness of a structured reduced dietary carbohydrate intervention and will compare the outcomes of this approach with a structured low fat eating plan. Trial Registration: The protocol for this study is registered with the International Clinical Trials Registry (ISRCTN49438757)

    Symbionts as Major Modulators of Insect Health: Lactic Acid Bacteria and Honeybees

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    Lactic acid bacteria (LAB) are well recognized beneficial host-associated members of the microbiota of humans and animals. Yet LAB-associations of invertebrates have been poorly characterized and their functions remain obscure. Here we show that honeybees possess an abundant, diverse and ancient LAB microbiota in their honey crop with beneficial effects for bee health, defending them against microbial threats. Our studies of LAB in all extant honeybee species plus related apid bees reveal one of the largest collections of novel species from the genera Lactobacillus and Bifidobacterium ever discovered within a single insect and suggest a long (>80 mya) history of association. Bee associated microbiotas highlight Lactobacillus kunkeei as the dominant LAB member. Those showing potent antimicrobial properties are acquired by callow honey bee workers from nestmates and maintained within the crop in biofilms, though beekeeping management practices can negatively impact this microbiota. Prophylactic practices that enhance LAB, or supplementary feeding of LAB, may serve in integrated approaches to sustainable pollinator service provision. We anticipate this microbiota will become central to studies on honeybee health, including colony collapse disorder, and act as an exemplar case of insect-microbe symbiosis
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