46,785 research outputs found
Depth mapping of integral images through viewpoint image extraction with a hybrid disparity analysis algorithm
Integral imaging is a technique capable of displaying 3–D images with continuous parallax in full natural color. It is one of the most promising methods for producing smooth 3–D images. Extracting depth information from integral image has various applications ranging from remote inspection, robotic vision, medical imaging, virtual reality, to content-based image coding and manipulation for integral imaging based 3–D TV. This paper presents a method of generating a depth map from unidirectional integral images through viewpoint image extraction and using a hybrid disparity analysis algorithm combining multi-baseline, neighbourhood constraint and relaxation strategies. It is shown that a depth map having few areas of uncertainty can be obtained from both computer and photographically generated integral images using this approach. The acceptable depth maps can be achieved from photographic captured integral images containing complicated object scene
Supplémentation en vitamine E chez des enfants sénégalais présentant un kwashiorkor
Le kwashiorkor pèse encore lourdement sur la mortalité infantile dans les pays en développement et une hypothèse récente suggère que cette forme de malnutrition pourrait être liée à l'agression oxydante de certaines substances. La vitamine E représente l'un des principaux anti-oxydants naturels et l'objectif de cette étude était d'évaluer si une supplémentation en vitamine E pouvait améliorer l'état des enfants souffrant de kwashiorkor. En parallèle, une supplémentation a également été programmée chez des enfants atteints de marasme. L'étude s'est déroulée d'octobre 1993 à juillet 1994 et porte sur 79 enfants (38 cas de kwashiorkor et 41 cas de marasme). Sur le plan évolutif, le protocole utilisé a permis d'obtenir 76% de guérison, le meilleur résultat (89,5%) ayant été enregistré chez les enfants atteints de marasme et supplémentés en vitamine E. En revanche, la supplémentation n'a eu aucun impact sur la qualité de la réhabilitation nutritionnelle. Dans le groupe des enfants atteints de kwashiorkor, le gain de poids, calculé après la disparition des oedèmes, était de 15,2 (+ ou -4,9) g/kg/j pour les enfants supplémentés en vitamine E et de 16,4 (+ ou - 3,6) g/kg/j pour ceux qui ne l'étaient pas. La durée des oedèmes durant la prise en charge était, par ailleurs, similaire dans les deux catégories (vitamine E : 8,6 (+ ou - 3) jours ; placebo : 7,1 (+ ou - 3,9) jours). Les raisons pouvant expliquer l'absence d'effet favorable de la supplémentation sont abordées dans la discussion. (Résumé d'auteur
Foraging Behavior of Tetramorium Caespitum in an Urban Environment: the Effect of Food Quality on Foraging
Animals\u27 foraging strategies are directly related to their fitness. Proposed models of optimal foraging assume that animals strategize in terms of maximizing benefits over the cost of acquiring resources. Ants are social insects that are comparable in biomass to humans inhabiting the plant. As such, it is crucial to understand the foraging strategies of such an influential member of the ecosystem. With the ever-increasing rate of urbanization and human encroachment, it is even more important to consider the foraging patterns of species inhabiting urban areas. In this study we investigate optimal foraging strategies in the pavement ant, Tetramorium caespitum. Specifically, our study examined if pavement ant colonies would alter their foraging behavior so as to maximize benefits and minimize costs. To do this, we exposed the ants to food of two varying nutritional qualities to test how they allocated foragers across these two resources.Food quantity, distance to the food source and terrain were the same in both types of resources. Across a two day period, we saw that T. caespitum colonies increased ant recruitment when food quality increased and decreased ant recruitment when food quality decreased. Our control treatments where food quality did not change also did not see a change in ant recruitment. This study shows that species that live in urban areas, such as T. caespitum, can adapt to forage optimally. Studies like this can be used to make predictions about survival of species that are newly associated with urban environments
The relationship between web enjoyment and student perceptions and learning using a web-based tutorial
Web enjoyment has been regarded as a component of system experience. However, there has been little targeted research considering the role of web enjoyment alone in student learning using web-based systems. To address this gap, this study aims to examine the influence of web enjoyment on learning performance and perceptions by controlling system experience as a variable in the study. 74 students participated in the study, using a web-based tutorial covering subject matter in the area of 'Computation and algorithms'. Their learning performance was assessed with a pre-test and a post-test and their learning perceptions were evaluated with a questionnaire. The results indicated that there are positive relationships between the levels of web enjoyment and perceived usefulness and non-linear navigation for users with similar, significant levels of system experience. The implications of these findings in relation to web-based learning are explored and ways in which the needs of students who report different levels of web enjoyment might be met are discussed
Sick and tired: how molecular regulators of human sleep schedules and duration impact immune function.
Why do we need to sleep? What regulates when we sleep? And what dictates the number of hours we require? These are often viewed as three separate biological questions. Here, we propose they share molecular etiologies, whereby regulators of sleep schedules and sleep duration also govern the physiological purposes of sleep. To support our hypothesis, we review Mendelian human genetic variants sufficient to advance sleep-wake onset (PER2) and shorten sleep length (DEC2), and evaluate their emerging roles in immune responses that may rely on a sound night of slumber
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Reversible writing of high-mobility and high-carrier-density doping patterns in two-dimensional van der Waals heterostructures
A key feature of two-dimensional materials is that the sign and concentration of their carriers can be externally controlled with techniques such as electrostatic gating. However, conventional electrostatic gating has limitations, including a maximum carrier density set by the dielectric breakdown, and ionic liquid gating and direct chemical doping also suffer from drawbacks. Here, we show that an electron-beam-induced doping technique can be used to reversibly write high-resolution doping patterns in hexagonal boron nitride-encapsulated graphene and molybdenum disulfide (MoS2) van der Waals heterostructures. The doped MoS2 device exhibits an order of magnitude decrease of subthreshold swing compared with the device before doping, whereas the doped graphene devices demonstrate a previously inaccessible regime of high carrier concentration and high mobility, even at room temperature. We also show that the approach can be used to write high-quality p–n junctions and nanoscale doping patterns, illustrating that the technique can create nanoscale circuitry in van der Waals heterostructures
How long does treatment with fixed orthodontic appliances last? A systematic review
INTRODUCTION
There is little agreement on the expected duration of a course of orthodontic treatment; however, a consensus appears to have emerged that fixed appliance treatment is overly lengthy. This has spawned numerous novel approaches directed at reducing the duration of treatment, occasionally with an acceptance that occlusal outcomes may be compromised. The aim of this study was to determine the mean duration and the number of visits required for comprehensive orthodontic treatment involving fixed appliances.
METHODS
Multiple electronic databases were searched with no language restrictions, authors were contacted as required, and reference lists of potentially relevant studies were screened. Randomized controlled trials and nonrandomized prospective studies concerning fixed appliance treatment with treatment duration as an outcome measure were included. Data extraction and quality assessment were performed independently and in duplicate.
RESULTS
Twenty-five studies were included after screening: 20 randomized controlled trials and 5 controlled clinical trials. Twenty-two studies were eligible for meta-analysis after quality assessment. The mean treatment duration derived from the 22 included studies involving 1089 participants was 19.9 months (95% confidence interval, 19.58, 20.22 months). Sensitivity analyses were carried out including 3 additional studies, resulting in average duration of treatment of 20.02 months (95% confidence interval, 19.71, 20.32 months) based on data from 1211 participants. The mean number of required visits derived from 5 studies was 17.81 (95% confidence interval, 15.47, 20.15 visits).
CONCLUSIONS
Based on prospective studies carried out in university settings, comprehensive orthodontic treatment on average requires less than 2 years to complete
Multi-Channel Stochastic Variational Inference for the Joint Analysis of Heterogeneous Biomedical Data in Alzheimer's Disease
The joint analysis of biomedical data in Alzheimer's Disease (AD) is
important for better clinical diagnosis and to understand the relationship
between biomarkers. However, jointly accounting for heterogeneous measures
poses important challenges related to the modeling of the variability and the
interpretability of the results. These issues are here addressed by proposing a
novel multi-channel stochastic generative model. We assume that a latent
variable generates the data observed through different channels (e.g., clinical
scores, imaging, ...) and describe an efficient way to estimate jointly the
distribution of both latent variable and data generative process. Experiments
on synthetic data show that the multi-channel formulation allows superior data
reconstruction as opposed to the single channel one. Moreover, the derived
lower bound of the model evidence represents a promising model selection
criterion. Experiments on AD data show that the model parameters can be used
for unsupervised patient stratification and for the joint interpretation of the
heterogeneous observations. Because of its general and flexible formulation, we
believe that the proposed method can find important applications as a general
data fusion technique.Comment: accepted for presentation at MLCN 2018 workshop, in Conjunction with
MICCAI 2018, September 20, Granada, Spai
Evidence for Non-Transmission of Rice Yellow Mottle Virus (RYMV) through Rice Seed
An indexing of the organs (radicle and plumule) and components (husk, endosperm and embryo) of rice seeds using Enzyme Linked Immunosorbent Assay (ELISA) was carried out to detect Rice yellow mottle virus (RYMV) and establish the exact location of the virus in the rice seed. RYMV was detected only in the husk (seed coat) but not in the endosperm, plumule, radicle, nor embryo. None of the seedlings raised from the seeds expressed RYMV symptoms. No virus particle was detected by the ELISA test in the leaves of the screenhouse-reared plants obtained from seeds of infected plants. The results indicate that RYMV is apparently not transmitted through rice seed probably because the virus is seed-borne in the husk (seed coat) of mature rice seeds
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