918 research outputs found

    Fully Onboard AI-Powered Human-Drone Pose Estimation on Ultralow-Power Autonomous Flying Nano-UAVs

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    Many emerging applications of nano-sized unmanned aerial vehicles (UAVs), with a few cm(2) form-factor, revolve around safely interacting with humans in complex scenarios, for example, monitoring their activities or looking after people needing care. Such sophisticated autonomous functionality must be achieved while dealing with severe constraints in payload, battery, and power budget (similar to 100 mW). In this work, we attack a complex task going from perception to control: to estimate and maintain the nano-UAV's relative 3-D pose with respect to a person while they freely move in the environment-a task that, to the best of our knowledge, has never previously been targeted with fully onboard computation on a nano-sized UAV. Our approach is centered around a novel vision-based deep neural network (DNN), called Frontnet, designed for deployment on top of a parallel ultra-low power (PULP) processor aboard a nano-UAV. We present a vertically integrated approach starting from the DNN model design, training, and dataset augmentation down to 8-bit quantization and deployment in-field. PULP-Frontnet can operate in real-time (up to 135 frame/s), consuming less than 87 mW for processing at peak throughput and down to 0.43 mJ/frame in the most energy-efficient operating point. Field experiments demonstrate a closed-loop top-notch autonomous navigation capability, with a tiny 27-g Crazyflie 2.1 nano-UAV. Compared against an ideal sensing setup, onboard pose inference yields excellent drone behavior in terms of median absolute errors, such as positional (onboard: 41 cm, ideal: 26 cm) and angular (onboard: 3.7 degrees, ideal: 4.1 degrees). We publicly release videos and the source code of our work

    Conferences in the time of COVID: notes on organizing and delivering the first Brain Conference

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    To further fulfil their missions of promoting teaching, education and research in neurology and related clinical-academic disciplines, the Guarantors of Brain and the Brain journal family invited delegates to the first Brain Conference in Spring of this year. This event aimed to deliver excellent teaching and scientific presentations across a broad spectrum of neuroscience fields, with the key aim of making the content as accessible as possible. We hoped to capitalize on the benefits of an online format, whilst trying to capture a little of the joy of the in-person meeting. This article reports on the approach and practical choices made to achieve these goals, and we hope this will provide some guidance and advice to others organizing their own online conference

    Prevalence and risk of violence and the mental, physical and sexual health problems associated with human trafficking: an updated systematic review.

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    BACKGROUND: To update and expand on a 2012 systematic review of the prevalence and risk of violence and the prevalence and risk of physical, mental and sexual health problems among trafficked people. METHOD: Systematic review and meta-analysis. Searches of 15 electronic databases of peer-reviewed articles and doctoral theses were supplemented by reference screening, citation tracking of included articles and expert recommendations. Studies were included if they reported on the prevalence or risk of violence while trafficked, or the prevalence or risk of physical, mental or sexual health outcomes among people who have been trafficked. Two reviewers independently screened papers for eligibility and appraised the quality of included studies. RESULTS: Thirty-seven papers reporting on 31 studies were identified. The majority of studies were conducted in low and middle-income countries with women and girls trafficked into the sex industry. There is limited but emerging evidence on the health of trafficked men and the health consequences of trafficking into different forms of exploitation. Studies indicate that trafficked women, men and children experience high levels of violence and report significant levels of physical health symptoms, including headaches, stomach pain and back pain. Most commonly reported mental health problems include depression, anxiety and post-traumatic stress disorder. Although serological data on sexually transmitted infections are limited, women and girls trafficked for sexual exploitation self-report symptoms suggestive of a high prevalence of infections. Limitations of the review include methodological weaknesses of primary studies and some differences in definition and operationalisation of trafficking, which hinder comparability and generalisability of the results. CONCLUSIONS: There is increasing evidence human trafficking is associated with high prevalence and increased risk of violence and a range of physical and mental health problems. Although more studies have emerged in recent years reporting on the health of trafficked men and people trafficked for forms of exploitation other than in the sex industry, further research is needed in this area. Appropriate interventions and support services to address the multiple and serious medical needs, especially mental health, of trafficked people are urgently needed

    Investigating the characteristics and correlates of systemic inflammation after traumatic brain injury: the TBI-BraINFLAMM study

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    INTRODUCTION: A significant environmental risk factor for neurodegenerative disease is traumatic brain injury (TBI). However, it is not clear how TBI results in ongoing chronic neurodegeneration. Animal studies show that systemic inflammation is signalled to the brain. This can result in sustained and aggressive microglial activation, which in turn is associated with widespread neurodegeneration. We aim to evaluate systemic inflammation as a mediator of ongoing neurodegeneration after TBI. METHODS AND ANALYSIS: TBI-braINFLAMM will combine data already collected from two large prospective TBI studies. The CREACTIVE study, a broad consortium which enrolled >8000 patients with TBI to have CT scans and blood samples in the hyperacute period, has data available from 854 patients. The BIO-AX-TBI study recruited 311 patients to have acute CT scans, longitudinal blood samples and longitudinal MRI brain scans. The BIO-AX-TBI study also has data from 102 healthy and 24 non-TBI trauma controls, comprising blood samples (both control groups) and MRI scans (healthy controls only). All blood samples from BIO-AX-TBI and CREACTIVE have already been tested for neuronal injury markers (GFAP, tau and NfL), and CREACTIVE blood samples have been tested for inflammatory cytokines. We will additionally test inflammatory cytokine levels from the already collected longitudinal blood samples in the BIO-AX-TBI study, as well as matched microdialysate and blood samples taken during the acute period from a subgroup of patients with TBI (n=18).We will use this unique dataset to characterise post-TBI systemic inflammation, and its relationships with injury severity and ongoing neurodegeneration. ETHICS AND DISSEMINATION: Ethical approval for this study has been granted by the London-Camberwell St Giles Research Ethics Committee (17/LO/2066). Results will be submitted for publication in peer-review journals, presented at conferences and inform the design of larger observational and experimental medicine studies assessing the role and management of post-TBI systemic inflammation

    Guidance on guidelines: Understanding the evidence on the uptake of health care guidelines

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    Rationale Regardless of health issue, health sector, patient condition, or treatment modality, the chances are that provision is supported by “a guideline” making professionally endorsed recommendations on best practice. Against this background, research has proliferated seeking to evaluate how effectively such guidance is followed. These investigations paint a gloomy picture with many a guideline prompting lip service, inattention, and even opposition. This predicament has prompted a further literature on how to improve the uptake of guidelines, and this paper considers how to draw together lessons from these inquiries. Methods This huge body of material presents a considerable challenge for research synthesis, and this paper produces a critical, methodological comparison of 2 types of review attempting to meet that task. Firstly, it provides an overview of the current orthodoxy, namely, “thematic reviews,” which aggregate and enumerate the “barriers and facilitators” to guideline implementation. It then outlines a “realist synthesis,” focussing on testing the “programme theories” that practitioners have devised to improve guideline uptake. Results Thematic reviews aim to provide a definitive, comprehensive catalogue of the facilitators and barriers to guideline implementation. As such, they present a restatement of the underlying problems rather than an improvement strategy. The realist approach assumes that the incorporation of any guideline into current practice will produce unintended system strains as different stakeholders wrestle over responsibilities. These distortions will prompt supplementary revisions to guidelines, which in turn beget further strains. Realist reviews follow this dynamic understanding of organisational change. Conclusions Health care decision makers operate in systems that are awash with guidelines. But guidelines only have paper authority. Managers do not need a checklist of their pros and cons, because the fate of guidelines depends on their reception rather than their production. They do need decision support on how to engineer and reengineer guidelines so they dovetail with evolving systems of health care delivery

    Human Mas-related G protein-coupled receptors-X1 induce chemokine receptor 2 expression in rat dorsal root ganglia neurons and release of chemokine ligand 2 from the human LAD-2 mast cell line

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    Primate-specific Mas-related G protein-coupled receptors-X1 (MRGPR-X1) are highly enriched in dorsal root ganglia (DRG) neurons and induce acute pain. Herein, we analyzed effects of MRGPR-X1 on serum response factors (SRF) or nuclear factors of activated T cells (NFAT), which control expression of various markers of chronic pain. Using HEK293, DRG neuron-derived F11 cells and cultured rat DRG neurons recombinantly expressing human MRGPR-X1, we found activation of a SRF reporter gene construct and induction of the early growth response protein-1 via extracellular signal-regulated kinases-1/2 known to play a significant role in the development of inflammatory pain. Furthermore, we observed MRGPR-X1-induced up-regulation of the chemokine receptor 2 (CCR2) via NFAT, which is considered as a key event in the onset of neuropathic pain and, so far, has not yet been described for any endogenous neuropeptide. Up-regulation of CCR2 is often associated with increased release of its endogenous agonist chemokine ligand 2 (CCL2). We also found MRGPR-X1-promoted release of CCL2 in a human connective tissue mast cell line endogenously expressing MRGPR-X1. Thus, we provide first evidence to suggest that MRGPR-X1 induce expression of chronic pain markers in DRG neurons and propose a so far unidentified signaling circuit that enhances chemokine signaling by acting on two distinct yet functionally co-operating cell types. Given the important role of chemokine signaling in pain chronification, we propose that interruption of this signaling circuit might be a promising new strategy to alleviate chemokine-promoted pain

    Shorter Food Chain Length in Ancient Lakes: Evidence from a Global Synthesis

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    Food webs may be affected by evolutionary processes, and effective evolutionary time ultimately affects the probability of species evolving to fill the niche space. Thus, ecosystem history may set important evolutionary constraints on community composition and food web structure. Food chain length (FCL) has long been recognized as a fundamental ecosystem attribute. We examined historical effects on FCL in large lakes spanning >6 orders of magnitude in age. We found that food chains in the world’s ancient lakes (n = 8) were significantly shorter than in recently formed lakes (n = 10) and reservoirs (n = 3), despite the fact that ancient lakes harbored much higher species richness, including many endemic species. One potential factor leading to shorter FCL in ancient lakes is an increasing diversity of trophic omnivores and herbivores. Speciation could simply broaden the number of species within a trophic group, particularly at lower trophic levels and could also lead to a greater degree of trophic omnivory. Our results highlight a counter-intuitive and poorly-understood role of evolutionary history in shaping key food web properties such as FCL

    Age-related changes in global motion coherence: conflicting haemodynamic and perceptual responses

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    Our aim was to use both behavioural and neuroimaging data to identify indicators of perceptual decline in motion processing. We employed a global motion coherence task and functional Near Infrared Spectroscopy (fNIRS). Healthy adults (n = 72, 18-85) were recruited into the following groups: young (n = 28, mean age = 28), middle-aged (n = 22, mean age = 50), and older adults (n = 23, mean age = 70). Participants were assessed on their motion coherence thresholds at 3 different speeds using a psychophysical design. As expected, we report age group differences in motion processing as demonstrated by higher motion coherence thresholds in older adults. Crucially, we add correlational data showing that global motion perception declines linearly as a function of age. The associated fNIRS recordings provide a clear physiological correlate of global motion perception. The crux of this study lies in the robust linear correlation between age and haemodynamic response for both measures of oxygenation. We hypothesise that there is an increase in neural recruitment, necessitating an increase in metabolic need and blood flow, which presents as a higher oxygenated haemoglobin response. We report age-related changes in motion perception with poorer behavioural performance (high motion coherence thresholds) associated with an increased haemodynamic response

    Right Paraduodenal Hernia in an Adult Patient: Diagnostic Approach and Surgical Management

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    Paraduodenal hernia, a rare congenital anomaly which arises from an error of rotation of the midgut, is the most common type of intraabdominal hernia. There are two variants, right and left paraduodenal hernia, the right being less common. We report the case of a 41-year-old patient with a right paraduodenal hernia with a 6-month history of intermittent episodes of intestinal obstruction. Diagnosis was established by CT scan and upper gastrointestinal series with small bowel follow-through. In a planned laparotomy, herniation of the small bowel loops through the fossa of Waldeyer was found. Division of the lateral right attachments of the colon opened the hernia sac widely, replacing the pre- and postarterial segments of the intestine in the positions they would normally occupy at the end of the first stage of rotation during embryonic development. Six months after the surgery, after an uneventful recovery, the patient remains free of symptoms
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