A contribution to vision-based autonomous helicopter flight in urban environments

A navigation strategy that exploits the optic flow and inertial information to continuously avoid collisions with both lateral and frontal obstacles has been used to control a simulated helicopter flying autonomously in a textured urban environment. Experimental results demonstrate that the corresponding controller generates cautious behavior, whereby the helicopter tends to stay in the middle of narrow corridors, while its forward velocity is automatically reduced when the obstacle density increases. When confronted with a frontal obstacle, the controller is also able to generate a tight U-turn that ensures the UAV’s survival. The paper provides comparisons with related work, and discusses the applicability of the approach to real platforms

Perspective: the application of a priori diet quality scores to cardiovascular disease risk: a critical evaluation of current scoring systems

Healthy dietary habits are the cornerstone of cardiovascular disease (CVD) prevention. Numerous researchers have developed diet quality indices to help evaluate and compare diet quality across and within various populations. The availability of these new indices raises questions regarding the best selection relevant to a given population. In this perspective, we critically evaluate a priori–defined dietary indices commonly applied in epidemiological studies of CVD risk and mortality. A systematic literature search identified 59 observational studies that applied a priori–defined diet quality indices to CVD risk factors and/or CVD incidence and/or CVD mortality. Among 31 different indices, these scores were categorized as follows: 1) those based on country-specific dietary patterns, 2) those adapted from distinct dietary guidelines, and 3) novel scores specific to key diet-related factors associated with CVD risk. The strengths and limitations of these indices are described according to index components, calculation methods, and the application of these indices to different population groups. Also, the importance of identifying methodological challenges faced by researchers when applying an index are considered, such as selection and weighting of food groups within a score, since food groups are not necessarily equivalent in their associations with CVD. The lack of absolute cutoff values, emphasis on increasing healthy food without limiting unhealthy food intake, and absence of validation of scores with biomarkers or other objective diet assessment methods further complicate decisions regarding the best indices to use. Future research should address these limitations, consider cross-cultural and other differences between population groups, and identify translational challenges inherent in attempting to apply a relevant diet quality index for use in CVD prevention at a population level

Influence of Rock-Pool Characteristics on the Distribution and Abundance of Inter-Tidal Fishes

Rock pools can be found in inter-tidal marine environments worldwide; however, there have been few studies exploring what drives their, fish species composition, especially in Australia. The rock-pool environment is highly dynamic and offers a unique natural laboratory to study the habitat choices, physiological limitations and adaptations of inter-tidal fish species. In this study rock pools of the Sydney region were sampled to determine how the physical (volume, depth, rock cover and vertical position) and biological (algal cover and predator presence) parameters of pools influence fish distribution and abundance. A total of 27 fish species representing 14 families was observed in tide pools at the four study locations. The five most abundant species were Bathygobius cocosensis, Centropogon australis, Enneapterygius atrogulare, Lepidoblennius haplodactylus and Microcanthus strigatus, which together represented 71% of the total number of fish recorded. Larger rock pools containing more algal and rock ledge cover hosted a larger and more diverse population of fish. Furthermore, certain species were only found in pools with specific characteristics, such as the presence of loose shells, a variety algae or rock cover, suggesting a high degree of habitat specificity. By contrast, some species were ubiquitous and thus can likely tolerate a wide variety of physical conditions

The association of fish consumption and its urinary metabolites with cardiovascular risk factors: The International Study of Macro-/Micronutrients and Blood Pressure (INTERMAP)

Background Results from observational studies regarding associations between fish (including shellfish) intake and cardiovascular disease risk factors, including blood pressure (BP) and BMI, are inconsistent. Objective To investigate associations of fish consumption and associated urinary metabolites with BP and BMI in free-living populations. Methods We used cross-sectional data from the International Study of Macro-/Micronutrients and Blood Pressure (INTERMAP), including 4680 men and women (40–59 y) from Japan, China, the United Kingdom, and United States. Dietary intakes were assessed by four 24-h dietary recalls and BP from 8 measurements. Urinary metabolites (2 timed 24-h urinary samples) associated with fish intake acquired from NMR spectroscopy were identified. Linear models were used to estimate BP and BMI differences across categories of intake and per 2 SD higher intake of fish and its biomarkers. Results No significant associations were observed between fish intake and BP. There was a direct association with fish intake and BMI in the Japanese population sample (P trend = 0.03; fully adjusted model). In Japan, trimethylamine-N-oxide (TMAO) and taurine, respectively, demonstrated area under the receiver operating characteristic curve (AUC) values of 0.81 and 0.78 in discriminating high against low fish intake, whereas homarine (a metabolite found in shellfish muscle) demonstrated an AUC of 0.80 for high/nonshellfish intake. Direct associations were observed between urinary TMAO and BMI for all regions except Japan (P < 0.0001) and in Western populations between TMAO and BP (diastolic blood pressure: mean difference 1.28; 95% CI: 0.55, 2.02 mmHg; P = 0.0006, systolic blood pressure: mean difference 1.67; 95% CI: 0.60, 2.73 mmHg; P = 0.002). Conclusions Urinary TMAO showed a stronger association with fish intake in the Japanese compared with the Western population sample. Urinary TMAO was directly associated with BP in the Western but not the Japanese population sample. Associations between fish intake and its biomarkers and downstream associations with BP/BMI appear to be context specific. INTERMAP is registered at www.clinicaltrials.gov as NCT00005271

3D deep convolutional neural network-based ventilated lung segmentation using multi-nuclear hyperpolarized gas MRI

Hyperpolarized gas MRI enables visualization of regional lung ventilation with high spatial resolution. Segmentation of the ventilated lung is required to calculate clinically relevant biomarkers. Recent research in deep learning (DL) has shown promising results for numerous segmentation problems. In this work, we evaluate a 3D V-Net to segment ventilated lung regions on hyperpolarized gas MRI scans. The dataset consists of 743 helium-3 (3He) or xenon-129 (129Xe) volumetric scans and corresponding expert segmentations from 326 healthy subjects and patients with a wide range of pathologies. We evaluated segmentation performance for several DL experimental methods via overlap, distance and error metrics and compared them to conventional segmentation methods, namely, spatial fuzzy c-means (SFCM) and K-means clustering. We observed that training on combined 3He and 129Xe MRI scans outperformed other DL methods, achieving a mean ± SD Dice of 0.958 ± 0.022, average boundary Hausdorff distance of 2.22 ± 2.16 mm, Hausdorff 95th percentile of 8.53 ± 12.98 mm and relative error of 0.087 ± 0.049. Moreover, no difference in performance was observed between 129Xe and 3He scans in the testing set. Combined training on 129Xe and 3He yielded statistically significant improvements over the conventional methods (p < 0.0001). The DL approach evaluated provides accurate, robust and rapid segmentations of ventilated lung regions and successfully excludes non-lung regions such as the airways and noise artifacts and is expected to eliminate the need for, or significantly reduce, subsequent time-consuming manual editing

Crowd Motion Capture

International audienceIn this paper a new and original technique to animate a crowd of human beings is presented. Following the success of data-driven animation models (such as motion capture) in the context of articulated figures control, we propose to derivate a similar type of approach for crowd motions. In our framework, the motion of the crowds are represented as a time series of velocity fields estimated from a video of a real crowd. This time series is used as an input of a simple animation model that ”advect” people along this timevarying flow. We demonstrate the power of our technique on both synthetic and real examples of crowd videos. We also introduce the notions of crowd motion editing and present possible extensions to our work

Association between plant-based diets and blood pressure in the INTERMAP study.

BACKGROUND: Plant-based diets are associated with a lower risk of cardiovascular diseases; however, little is known how the healthiness of the diet may be associated with blood pressure (BP). We aimed to modify three plant -based diet indices: overall plant-based diet index (PDI), healthy PDI (hPDI), and unhealthy PDI (uPDI) according to country-specific dietary guidelines to enable use across populations with diverse dietary patterns - and assessed their associations with BP. DESIGN: We used cross-sectional data including 4,680 men and women ages 40-59y in Japan, China, the United Kingdom, and the United States from the INTERnational study on MAcro/micronutrients and blood Pressure (INTERMAP). During four visits, eight BP measurements, and four 24-h dietary recalls were collected. Multivariable regression coefficients were estimated, pooled, weighted, and adjusted extensively for lifestyle/dietary confounders. RESULTS: Modified PDI was not associated with BP. Consumption of hPDI higher by 1SD was inversely associated with systolic (-0.82 mm Hg;95% CI:-1.32,-0.49) and diastolic BP (-0.49 mm Hg; 95% CI:-0.91, -0.28). In contrast, consumption of an uPDI was directly associated with systolic (0.77 mm Hg;95% CI:0.30,1.20). Significant associations between hPDI with BP were attenuated with separate adjustment for vegetables and whole grains; associations between uPDI and BP were attenuated after adjustment for refined grains, sugar-sweetened beverages, and meat. CONCLUSION: An hPDI is associated with lower BP while a uPDI is adversely related to BP. Plant-based diets rich in vegetables and whole grains and limited in refined grains, sugar-sweetened beverages, and total meat may contribute to these associations. In addition to current guidelines, the nutritional quality of consumed plant foods is as important as limiting animal-based components. TRIAL REGISTRATION NUMBER: The observational INTERMAP study was registered at www.clinicaltrials.gov as NCT00005271

The genome sequence of <i>Trypanosoma brucei gambiense</i>, causative agent of chronic Human African Trypanosomiasis

&lt;p&gt;&lt;b&gt;Background:&lt;/b&gt; &lt;i&gt;Trypanosoma brucei gambiense&lt;/i&gt; is the causative agent of chronic Human African Trypanosomiasis or sleeping sickness, a disease endemic across often poor and rural areas of Western and Central Africa. We have previously published the genome sequence of a &lt;i&gt;T. b. brucei&lt;/i&gt; isolate, and have now employed a comparative genomics approach to understand the scale of genomic variation between &lt;i&gt;T. b. gambiense&lt;/i&gt; and the reference genome. We sought to identify features that were uniquely associated with &lt;i&gt;T. b. gambiense&lt;/i&gt; and its ability to infect humans.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods and findings:&lt;/b&gt; An improved high-quality draft genome sequence for the group 1 &lt;i&gt;T. b. gambiense&lt;/i&gt; DAL 972 isolate was produced using a whole-genome shotgun strategy. Comparison with &lt;i&gt;T. b. brucei&lt;/i&gt; showed that sequence identity averages 99.2% in coding regions, and gene order is largely collinear. However, variation associated with segmental duplications and tandem gene arrays suggests some reduction of functional repertoire in &lt;i&gt;T. b. gambiense&lt;/i&gt; DAL 972. A comparison of the variant surface glycoproteins (VSG) in &lt;i&gt;T. b. brucei&lt;/i&gt; with all &lt;i&gt;T. b. gambiense&lt;/i&gt; sequence reads showed that the essential structural repertoire of VSG domains is conserved across &lt;i&gt;T. brucei&lt;/i&gt;.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions:&lt;/b&gt; This study provides the first estimate of intraspecific genomic variation within &lt;i&gt;T. brucei&lt;/i&gt;, and so has important consequences for future population genomics studies. We have shown that the &lt;i&gt;T. b. gambiense&lt;/i&gt; genome corresponds closely with the reference, which should therefore be an effective scaffold for any &lt;i&gt;T. brucei&lt;/i&gt; genome sequence data. As VSG repertoire is also well conserved, it may be feasible to describe the total diversity of variant antigens. While we describe several as yet uncharacterized gene families with predicted cell surface roles that were expanded in number in &lt;i&gt;T. b. brucei&lt;/i&gt;, no &lt;i&gt;T. b. gambiense&lt;/i&gt;-specific gene was identified outside of the subtelomeres that could explain the ability to infect humans.&lt;/p&gt

A Comparison of Interventions for Children with Cerebral Palsy to Improve Sitting Postural Control: A Clinical Trial

Background The ability to sit independently is fundamental for function but delayed in infants with cerebral palsy (CP). Studies of interventions directed specifically toward sitting in infants with CP have not been reported. Objective The purpose of this study was to compare 2 interventions for improving sitting postural control in infants with CP. Design For this randomized longitudinal study, infants under 2 years of age and at risk for CP were recruited for intervention directed toward sitting independence. Setting The intervention was conducted at home or at an outpatient facility. Patients and Intervention Fifteen infants with typical development (mean age at entry=5 months, SD=0.5) were followed longitudinally as a comparison for postural variables. Thirty-five infants with delays in achieving sitting were recruited. Infants with delays were randomly assigned to receive a home program (1 time per week for 8 weeks; mean age=15.5 months, SD=7) or a perceptual-motor intervention (2 times per week for 8 weeks; mean age=14.3 months, SD=3). Measurements The primary outcome measure was center-of-pressure (COP) data, from which linear and nonlinear variables were extracted. The Gross Motor Function Measure (GMFM) sitting subsection was the clinical outcome measure. Results There was a main effect of time for the GMFM sitting subscale and for 2 of the COP variables. Interaction of group × time factors indicated significant differences between intervention groups on 2 COP measures, in favor of the group with perceptual-motor intervention. Limitations The small number of infants limits the ability to generalize the findings. Conclusions Although both groups made progress on the GMFM, the COP measures indicated an advantage for the group with perceptual-motor intervention. The COP measures appear sensitive for assessment of infant posture control and quantifying intervention response