Reconstructing 3D trajectories of independently moving objects using generic constraints

The 3D reconstruction of scenes containing independently moving objects from uncalibrated monocular sequences still poses serious challenges. Even if the background and the moving objects are rigid, each reconstruction is only known up to a certain scale, which results in a one-parameter family of possible, relative trajectories per moving object with respect to the background. In order to determine a realistic solution from this family of possible trajectories, this paper proposes to exploit the increased linear coupling between camera and object translations that tends to appear at false scales. An independence criterion is formulated in the sense of true object and camera motions being minimally correlated. The increased coupling at false scales can also lead to the destruction of special properties such as planarity, periodicity, etc. of the true object motion. This provides us with a second, ‘non-accidentalness’ criterion for the selection of the correct motion among the one-parameter family.     

Planning and Control of Straight-Ahead and Angled Planar Movements in Adults and Young Children.

In the present study we wanted to determine why straight-ahead movements performed along one's midline are directionally more accurate than movements toward eccentric targets. We also wanted to determine whether the processes underlying this difference were the same in young children as in adults. Six-to-seven-year-old children and adults practiced a video-aiming task using different starting base and target combinations without vision of their ongoing movements. The results indicated that adults and children were directionally more accurate and less variable when pointing toward targets located straight ahead of the starting base rather than eccentric or concentric targets. This was true, regardless of whether the movement was performed along one's midline or not. These results suggest that angled movements are directionally less accurate than straight-ahead movements because of difficulty in defining the orientation of the appropriate movement vector in the workspace and/or in transforming it into appropriate motor commands. A kinematic analysis revealed large coefficients of direction and of extent variability early after movement initiation. However, these coefficients of variability were largely reduced by the occurrence of peak extent velocity, revealing that noise in initial movement planning was quickly reduced by on-line control processes. Finally, the results indicated largely similar planning and control processes for young children and adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Morphological and chemical studies of pathological human and mice brain at the subcellular level: correlation between light, electron, and nanosims microscopies

Neurodegenerative diseases induce morphological and chemical alterations in well-characterized regions of the brain. Understanding their pathological processes requires the use of methods that assess both morphological and chemical alterations in the tissues. In the past, microprobe approaches such as scanning electron microscopy combined with an X-ray spectrometer, Proton induced X-ray emission, secondary ion mass spectrometry (SIMS), and laser microprobe mass analysis have been used for the study of pathological human brain with limited success. At the present, new SIMS instruments have been developed, such as the NanoSIMS-50 ion microprobe, that allow the simultaneous identification of five elements with high sensitivity, at subcellular spatial resolution (about 50-100 nm with the Cs(+) source and about 150-200 nm with O(-) source). Working in scanning mode, 2D distribution of five elements (elemental maps) can be obtained, thus providing their exact colocalization. The analysis can be performed on semithin or ultrathin embedded sections. The possibility of using transmission electron microscopy and SIMS on the same ultrathin sections allows the correlation between structural and analytical observations at subcellular and ultrastructural level to be established. Our observations on pathological brain areas allow us to establish that the NanoSIMS-50 ion microprobe is a highly useful instrument for the imaging of the morphological and chemical alterations that take place in these brain areas. In the human brain our results put forward the subcellular distribution of iron-ferritin-hemosiderin in the hippocampus of Alzheimer disease patients. In the thalamus of transgenic mice, our results have shown the presence of Ca-Fe mineralized amyloid deposits.     

Lipase catalyzed synthesis of polycaprolactone and clay-based nanohybrids

This study presents the use of original systems based on Candida antarctica lipase B (CALB) immobilized on montmorillonite and sepiolite nanoclays as efficient catalysts for the enzymatic polymerization of ε-caprolactone (ε-CL) and the in situ elaboration of nanohybrids.     

Digital neighborhoods

With the advent of ‘big data’ there is an increased interest in using social media to describe city dynamics. This paper employs geo-located social media data to identify ‘digital neighborhoods’ – those areas in the city where social media is used more often. Starting with geo-located Twitter and Foursquare data for the New York City region in 2014, we applied spatial clustering techniques to detect significant groupings or ‘neighborhoods’ where social media use is high or low. The results show that beyond the business districts, digital neighborhoods occur in communities undergoing shifting socio-demographics. Neighborhoods that are not digitally oriented tend to have higher proportion of minorities and lower incomes, highlighting a social–economic divide in how social media is used in the city. Understanding the differences in these neighborhoods can help city planners interested in generating economic development proposals, civic engagement strategies, and urban design ideas that target these areas.     

Macromolecular structure of water-extractable arabinoxylans in endosperm and wholemeal rye breads as factor controlling their extract viscosities

Viscosity is one of the most important attributes of rye-based products related to some health benefits. To identify the factors affecting arabinoxylan-dependent extract viscosity (AX-EV) of rye bread, the structural features of water-extractable arabinoxylans (WE-AXs) and their ammonium sulphate precipitated subfractions were investigated in breads with varied viscosities. Also, an endoxylanase activity in the starting flours was examined. The HPSEC-RI profiles revealed the higher extent of AX depolymerisation in whole-meal bread (WMB) when compared to that in endosperm bread (EB), resulting in its lower AX-EV. This was mostly related to lower molecular weight of the parent WE-AX fraction with distinctly lower proportion of 2-Xylp in the chain. The AX-EV of rye bread decreased with decreasing proportion of AX-I, the major subfraction with 3-Xylp as only branching site. The endoxylanase activity was at least two times lower in endosperm flour than that in WM and negatively correlated with the AX-EV of WMB. The importance of densely substituted AX subfractions with exclusively 2-Xylp and 2,3-Xylp branches, protecting the AX-I from enzymic degradation during bread-making, has been evidenced.     

GD&T-Based Characterization of Short-Range Non-contact 3D Imaging Systems

We present a series of test metrics, artifacts, and procedures for characterizing and verifying the operating limits of a short-range non-contact three-dimensional imaging system. These metrics have been designed to correspond to dimensioning and tolerancing metrics that are widely used in industry (e.g. automotive, aerospace, etc.). We introduce operating limit metrics that correspond with the geometric dimensioning and tolerancing (GD&T) metrics of Form (Flatness and Circularity), Orientation (Angularity), Location (Sphere, Corner, and Hole Position Errors), and Size (Diameter, Sphere-spacing, Plane-spacing and Angle Errors). An example is presented to illustrate how these metrics, artifacts, and associated test procedures can be used in practice.     

The Effect of Implanted Al and/or Y on the Scale Formation on Low-Al Fe20Cr2Al Alloy

The very early stages of the oxidation of an Fe20Cr2Al alloy, unmodified and ion-implanted by aluminium, yttrium and a combination of both elements, Al and Y, were studied at 1100 °C in oxygen using two-stage-oxidation exposures with ¹⁸O₂ as a tracer and subsequent characterisation of the scales using SIMS analyses of distribution of oxygen isotopes and oxide-related negative ion clusters, SEM observations of the surface morphology and photoluminescence spectroscopy analysis of the phase composition. The scales formed in all cases, except for the Al-implanted alloy, exhibited layered structures, with the outer part comprising Fe- and Cr-rich oxide, and the inner part being Al₂O₃, which grew due to a mixed outward–inward mechanism . The alumina sub-layers contained the transient oxides and α-Al₂O₃. Implanted Al significantly affected the mechanism of the scale growth, providing that the scale consisted essentially of α-Al₂O₃, and grew via a mixed inward-outward mechanism typical for scales on alumina formers.