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Sandra Pizzarello, Everett Shock
The biogenic elements, H, C, N, O, P and S, have a long cosmic history, whose evolution can still be observed in diverse locales of the known universe, from interstellar clouds of gas and dust, to pre-stellar cores, nebulas, protoplanetary discs, planets and planetesimals. The best analytical window into this cosmochemical evolution as it neared Earth has been provided so far by the small bodies of the Solar System, some of which were not significantly altered by the high gravitational pressures and temperatures that accompanied the formation of larger planets and may carry a pristine record of early nebular chemistry...
January 11, 2017: Origins of Life and Evolution of the Biosphere
Dilek Guven, Zeynep Acar, Mehmet Demir, Yekta Sendul, Atilla Gokce Demir, Erdem Ergen
A 21-year-old female presented with a 4-day history of decreased vision in her only functional eye (right eye, OD). She had a history of multiple ocular surgeries in both eyes because of congenital glaucoma and had lost light perception in her left eye several years prior. Ophthalmological examination revealed 0.15 Snellen visual acuity, and fundoscopy revealed nearly total cupping and pallor of the optic disc and multiple retinal hemorrhagic foci in the macula in OD. Lesions spontaneously resolved over a few months...
November 2016: Arquivos Brasileiros de Oftalmologia
Bahe Hachem, Carl-Eric Aubin, Stefan Parent
PURPOSE: Developing fusionless devices to treat pediatric scoliosis necessitates lengthy and expensive animal trials. The objective was to develop and validate a porcine spine numerical model as an alternative platform to assess fusionless devices. METHODS: A parametric finite element model (FEM) of an osseoligamentous porcine spine and rib cage, including the epiphyseal growth plates, was developed. A follower-type load replicated physiological and gravitational loads...
January 9, 2017: European Spine Journal
T Can, Y H Chiu, M Laskin, P Wiegmann
We study quantum Hall states on surfaces with conical singularities. We show that the electronic fluid at the cone tip possesses an intrinsic angular momentum, which is due solely to the gravitational anomaly. We also show that quantum Hall states behave as conformal primaries near singular points, with a conformal dimension equal to the angular momentum. Finally, we argue that the gravitational anomaly and conformal dimension determine the fine structure of the electronic density at the conical point. The singularities emerge as quasiparticles with spin and exchange statistics arising from adiabatically braiding conical singularities...
December 23, 2016: Physical Review Letters
Andrew A Geraci, Andrei Derevianko
We discuss the use of atom interferometry as a tool to search for dark matter (DM) composed of virialized ultralight fields (VULFs). Previous work on VULF DM detection using accelerometers has considered the possibility of equivalence-principle-violating effects whereby gradients in the dark matter field can directly produce relative accelerations between media of differing composition. In atom interferometers, we find that time-varying phase signals induced by coherent oscillations of DM fields can also arise due to changes in the atom rest mass that can occur between light pulses throughout the interferometer sequence as well as changes in Earth's gravitational field...
December 23, 2016: Physical Review Letters
Aizhu Zhang, Genyun Sun, Jinchang Ren, Xiaodong Li, Zhenjie Wang, Xiuping Jia
Balancing exploration and exploitation according to evolutionary states is crucial to meta-heuristic search (M-HS) algorithms. Owing to its simplicity in theory and effectiveness in global optimization, gravitational search algorithm (GSA) has attracted increasing attention in recent years. However, the tradeoff between exploration and exploitation in GSA is achieved mainly by adjusting the size of an archive, named Kbest, which stores those superior agents after fitness sorting in each iteration. Since the global property of Kbest remains unchanged in the whole evolutionary process, GSA emphasizes exploitation over exploration and suffers from rapid loss of diversity and premature convergence...
December 30, 2016: IEEE Transactions on Cybernetics
B S Shenkman
Skeletal muscle consists of different fiber types arranged in a mosaic pattern. These fiber types are characterized by specific functional properties. Slow-type fibers demonstrate a high level of fatigue resistance and prolonged contraction duration, but decreased maximum contraction force and velocity. Fast-type fibers demonstrate high contraction force and velocity, but profound fatigability. During the last decades, it has been discovered that all these properties are determined by the predominance of slow or fast myosin-heavy-chain (MyHC) isoforms...
October 2016: Acta Naturae
Mishaela DiNino, Richard A Wright, Matthew B Winn, Julie Arenberg Bierer
Suboptimal interfaces between cochlear implant (CI) electrodes and auditory neurons result in a loss or distortion of spectral information in specific frequency regions, which likely decreases CI users' speech identification performance. This study exploited speech acoustics to model regions of distorted CI frequency transmission to determine the perceptual consequences of suboptimal electrode-neuron interfaces. Normal hearing adults identified naturally spoken vowels and consonants after spectral information was manipulated through a noiseband vocoder: either (1) low-, middle-, or high-frequency regions of information were removed by zeroing the corresponding channel outputs, or (2) the same regions were distorted by splitting filter outputs to neighboring filters...
December 2016: Journal of the Acoustical Society of America
Ludmila Yakushevich
The creation of mechanical analogues of biological systems is known as a useful instrument that helps to understand better the dynamical mechanisms of the functioning of living organisms. Mechanical analogues of biomolecules are usually constructed for imitation of their internal mobility, which is one of the most important properties of the molecules. Among the different types of internal motions, angular oscillations of nitrous bases are of special interest because they make a substantial contribution to the base pairs opening that in turn is an important element of the process of the DNA-protein recognition...
December 30, 2016: Journal of Biological Physics
Bruno Estañol, Ana Leonor Rivera, Raúl Martínez Memije, Ruben Fossion, Fermín Gómez, Katherine Bernal, Sofía Murúa Beltrán, Guillermo Delgado-García, Alejandro Frank
Myogenic vascular response is a form of systemic and regional vasoconstriction produced increasing the intra-arterial pressure by gravity. Here, the vasoconstriction due to the myogenic response, induced by the gravitational action in a dependent limb, is separated from that caused by the baroreceptor reflex. Regional changes of skin blood flow (SBF), total blood volume of the finger (TBVF), pulse pressure (PP), heart rate (HR), systolic, and diastolic blood pressure (BP) were analyzed in 10 healthy young subjects in supine and upright positions...
December 2016: Physiological Reports
Andrea Isella, Greta Guidi, Leonardo Testi, Shangfei Liu, Hui Li, Shengtai Li, Erik Weaver, Yann Boehler, John M Carperter, Itziar De Gregorio-Monsalvo, Carlo F Manara, Antonella Natta, Laura M Pérez, Luca Ricci, Anneila Sargent, Marco Tazzari, Neal Turner
We present Atacama Large Millimeter and Submillimeter Array observations of the protoplanetary disk around the Herbig Ae star HD 163296 that trace the spatial distribution of millimeter-sized particles and cold molecular gas on spatial scales as small as 25 astronomical units (A.U.). The image of the disk recorded in the 1.3 mm continuum emission reveals three dark concentric rings that indicate the presence of dust depleted gaps at about 60, 100, and 160 A.U. from the central star. The maps of the ^{12}CO, ^{13}CO, and C^{18}O J=2-1 emission do not show such structures but reveal a change in the slope of the radial intensity profile across the positions of the dark rings in the continuum image...
December 16, 2016: Physical Review Letters
Michał Teżyk, Emilia Jakubowska, Kasylda Milczewska, Bartłomiej Milanowski, Adam Voelkel, Janina Lulek
OBJECTIVE: The aim of this article is to compare the gravitational powder blend loading method to the tablet press and manual loading in terms of their influence on tablets' critical quality attributes (CQA). SIGNIFICANCE: The results of the study can be of practical relevance to the pharmaceutical industry in the area of direct compression of low dose formulations, which could be prone to content uniformity issues. METHODS: In the preliminary study particle size distribution and surface energy of raw materials were determined using laser diffraction method and inverse gas chromatography, respectively...
December 29, 2016: Drug Development and Industrial Pharmacy
Takahiro Abe, Shuichi Nakamura, Seishi Kudo
Bacterial chemotaxis allows cells to swim toward a more favorable environment. Capillary assays are a major method for exploring bacterial responses to attractive and repellent chemicals, but the accumulation process obtained using a capillary containing chemicals has not been investigated fully. In this study, we quantitatively analyzed the response of Salmonella cells to serine as an attractant diffusing from a capillary placed in a cell suspension. Video microscopy showed that cells gradually accumulated near the tip of the capillary and thereafter directed flows were generated...
December 23, 2016: Biochemical and Biophysical Research Communications
Katelyn Cahill-Rowley, Jessica Rose
Reaching is a well-practiced functional task crucial to daily living activities, and temporal-spatial measures of reaching reflect function for both adult and pediatric populations with upper-extremity motor impairments. Inertial sensors offer a mobile and inexpensive tool for clinical assessment of movement. This research outlines a method for measuring temporal-spatial reach parameters using inertial sensors, and validates these measures with traditional marker-based motion capture. 140 reaches from 10 adults, and 30 reaches from nine children aged 18-20 months, were recorded and analyzed using both inertial-sensor and motion-capture methods...
October 26, 2016: Journal of Biomechanics
Wolfgang Tichy
Spacetime is foliated by spatial hypersurfaces in the 3+1 split of general relativity. The initial value problem then consists of specifying initial data for all fields on one such a spatial hypersurface, such that the subsequent evolution forward in time is fully determined. On each hypersurface the 3-metric and extrinsic curvature describe the geometry. Together with matter fields such as fluid velocity, energy density and rest mass density, the 3-metric and extrinsic curvature then constitute the initial data...
December 23, 2016: Reports on Progress in Physics
Paolo Tommasino, Domenico Campolo
In this work, we address human-like motor planning in redundant manipulators. Specifically, we want to capture postural synergies such as Donders' law, experimentally observed in humans during kinematically redundant tasks, and infer a minimal set of parameters to implement similar postural synergies in a kinematic model. For the model itself, although the focus of this paper is to solve redundancy by implementing postural strategies derived from experimental data, we also want to ensure that such postural control strategies do not interfere with other possible forms of motion control (in the task space), i...
December 22, 2016: Bioinspiration & Biomimetics
Ruonan Wu, Qiuping Wu, Fengtian Han, Tianyi Liu, Peida Hu, Haixia Li
The gravity disturbance vector is one of the major error sources in high-precision and long-term inertial navigation applications. Specific to the inertial navigation systems (INSs) with high-order horizontal damping networks, analyses of the error propagation show that the gravity-induced errors exist almost exclusively in the horizontal channels and are mostly caused by deflections of the vertical (DOV). Low-frequency components of the DOV propagate into the latitude and longitude errors at a ratio of 1:1 and time-varying fluctuations in the DOV excite Schuler oscillation...
December 18, 2016: Sensors
Christopher R Lattimer, Stephen Doucet, George Geroulakos, Evi Kalodiki
BACKGROUND: Venous drainage from the leg is poorly understood, and it is difficult to quantify it hemodynamically. Attempts have been made using duplex ultrasound scanning and venous occlusion air plethysmography (APG). However, they have limited value in day-to-day clinical practice. This is because venous drainage measurements have never been validated successfully against increasing obstruction pressures. The hypothesis is that the novel gravitational venous drainage index (VDI) in milliliters/second is reduced in response to increasing venous obstruction, and the aim was to quantify this, using stepwise inflations of a thigh cuff...
January 2017: Journal of Vascular Surgery. Venous and Lymphatic Disorders
Sammy Sinno, Rohini Kadel, Neil Tanna, Barry M Zide
BACKGROUND: The senior author has previously described a deep-plane cervicofacial hike flap as a workhorse for reconstruction mid-cheek defects. One important modification commonly used involves overcorrection of the defect in order to reduce the incidence of ectropion. This report outlines the senior author's experience in surgical treating complex cheek defects with an overcorrected deep-plane cervicofacial hike flap. METHODS: The authors performed a retrospective review of the senior author's patients with cheek and eyelid reconstruction...
December 12, 2016: Journal of Craniofacial Surgery
Li-Wei Wei, Frédéric Cleva, Catherine Nary Man
Stable low-noise high-power lasers are indispensable in advancing the strain sensitivity of interferometric gravitational wave detectors. Advanced LIGO and Advanced Virgo are currently under commissioning and require about 200 W of single-frequency laser power, while the future detector design may require up to the order of 500 W. In this Letter, we present the design and, to the best of our knowledge, the first experimental demonstration of the laser system for Advanced Virgo that is based on coherently combined fiber laser amplifiers...
December 15, 2016: Optics Letters
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