1,548 research outputs found
Regional body composition in college-aged Caucasians from anthropometric measures
<p>Abstract</p> <p>Background</p> <p>Quantitating fat and lean tissue in isolated body regions may be helpful or required in obesity and health-outcomes research. However, current methods of regional body composition measurement require specialized, expensive equipment such as that used in computed tomography or dual energy x-ray absorptiometry (DEXA). Simple body size or circumference measurement relationships to body composition have been developed but are limited to whole-body applications. We investigated relationships between body size measurements and regional body composition.</p> <p>Methods</p> <p>Using DEXA technology we determined the fat and lean tissue composition for six regions of the body in predominantly Caucasian, college-aged men (n = 32) and women (n = 67). Circumference measurements as well as body weight and height were taken for each individual. Equations relating body measurements to a respective regional fat and lean mass were developed using multiple regression analysis.</p> <p>Results</p> <p>Multiple regression R<sup>2 </sup>values ranged from 0.4451 to 0.8953 and 0.1697 to 0.7039 for regional fat and lean mass relationships to body measurements, respectively.</p> <p>Conclusion</p> <p>The equations developed in this study offer a simple way of estimating regional body composition in a college-aged adult population. The parameters used in the equations are common body measurements that can be obtained with the use of a measuring tape and weight scale.</p
On some fundamental results about higher-rank graphs and their C*-algebras
Results of Fowler and Sims show that every k-graph is completely determined
by its k-coloured skeleton and collection of commuting squares. Here we give an
explicit description of the k-graph associated to a given skeleton and
collection of squares and show that two k-graphs are isomorphic if and only if
there is an isomorphism of their skeletons which preserves commuting squares.
We use this to prove directly that each k-graph {\Lambda} is isomorphic to the
quotient of the path category of its skeleton by the equivalence relation
determined by the commuting squares, and show that this extends to a
homeomorphism of infinite-path spaces when the k-graph is row finite with no
sources. We conclude with a short direct proof of the characterisation,
originally due to Robertson and Sims, of simplicity of the C*-algebra of a
row-finite k-graph with no sources.Comment: 21 pages, two pictures prepared using TiK
Geochemical assessment of the degree of isolation of edge-of-aquifer groundwater along a fringe of the southern High Plains Aquifer, USA
© 2019, The Author(s). The edge of regional aquifers can be complex hydrodynamic systems with unique flow dynamics, water quality, and continuity relationships with the main aquifer system. A site near the southwestern margin of the High Plains Aquifer (USA) was investigated to characterize the local hydrogeology and its relationship with the regional aquifer system. Measurements of tritium, ion concentrations, oxygen and hydrogen isotopes, and hydraulic heads documented (1) a discontinuous saturated zone, (2) no inflow to the study area from the regional aquifer, (3) focused recharge beneath playas with limited local mixing between pockets of saturation, (4) outflow orthogonal to the regional aquifer flow direction, (5) localized multi-year reversals in flow direction following high precipitation events, and (6) a magnified influence of the paleo-erosional surface of the basement rock (Dockum Group) on groundwater isolation and flow direction. In isolated areas, groundwater can be trapped on decadal time scales by depressions in the Dockum, or by recharge events that periodically reverse groundwater gradients
Deep Spiking Neural Network model for time-variant signals classification: a real-time speech recognition approach
Speech recognition has become an important task
to improve the human-machine interface. Taking into account
the limitations of current automatic speech recognition systems,
like non-real time cloud-based solutions or power demand,
recent interest for neural networks and bio-inspired systems has
motivated the implementation of new techniques.
Among them, a combination of spiking neural networks and
neuromorphic auditory sensors offer an alternative to carry
out the human-like speech processing task. In this approach,
a spiking convolutional neural network model was implemented,
in which the weights of connections were calculated by training
a convolutional neural network with specific activation functions,
using firing rate-based static images with the spiking information
obtained from a neuromorphic cochlea.
The system was trained and tested with a large dataset
that contains ”left” and ”right” speech commands, achieving
89.90% accuracy. A novel spiking neural network model has been
proposed to adapt the network that has been trained with static
images to a non-static processing approach, making it possible
to classify audio signals and time series in real time.Ministerio de Economía y Competitividad TEC2016-77785-
Superoxide dismutase downregulation in osteoarthritis progression and end-stage disease
Oxidative stress is proposed as an important factor in osteoarthritis (OA). To investigate the expression of the three superoxide dismutase (SOD) antioxidant enzymes in OA. SOD expression was determined by real-time PCR and immunohistochemistry using human femoral head cartilage. SOD2 expression in Dunkin–Hartley guinea pig knee articular cartilage was determined by immunohistochemistry. The DNA methylation status of the SOD2 promoter was determined using bisulphite sequencing. RNA interference was used to determine the consequence of SOD2 depletion on the levels of reactive oxygen species (ROS) using MitoSOX and collagenases, matrix metalloproteinase 1 (MMP-1) and MMP-13, gene expression. All three SOD were abundantly expressed in human cartilage but were markedly downregulated in end-stage OA cartilage, especially SOD2. In the Dunkin–Hartley guinea pig spontaneous OA model, SOD2 expression was decreased in the medial tibial condyle cartilage before, and after, the development of OA-like lesions. The SOD2 promoter had significant DNA methylation alterations in OA cartilage. Depletion of SOD2 in chondrocytes increased ROS but decreased collagenase expression. This is the first comprehensive expression profile of all SOD genes in cartilage and, importantly, using an animal model, it has been shown that a reduction in SOD2 is associated with the earliest stages of OA. A decrease in SOD2 was found to be associated with an increase in ROS but a reduction of collagenase gene expression, demonstrating the complexities of ROS function
Development of a Coherent Lidar for Aiding Precision Soft Landing on Planetary Bodies
Coherent lidar can play a critical role in future planetary exploration missions by providing key guidance, navigation, and control (GNC) data necessary for navigating planetary landers to the pre-selected site and achieving autonomous safe soft-landing. Although the landing accuracy has steadily improved over time to approximately 35 km for the recent Mars Exploration Rovers due to better approach navigation, a drastically different guidance, navigation and control concept is required to meet future mission requirements. For example, future rovers will require better than 6 km landing accuracy for Mars and better than 1 km for the Moon plus maneuvering capability to avoid hazardous terrain features. For this purpose, an all-fiber coherent lidar is being developed to address the call for advancement of entry, descent, and landing technologies. This lidar will be capable of providing precision range to the ground and approach velocity data, and in the case of landing on Mars, it will also measure the atmospheric wind and density. The lidar obtains high resolution range information from a frequency modulated-continuous wave (FM-CW) laser beam whose instantaneous frequency varies linearly with time, and the ground vector velocity is directly extracted from the Doppler frequency shift. Utilizing the high concentration of aerosols in the Mars atmosphere (approx. two order of magnitude higher than the Earth), the lidar can measure wind velocity with a few watts of optical power. Operating in 1.57 micron wavelength regime, the lidar can use the differential absorption (DIAL) technique to measure the average CO2 concentration along the laser beam using, that is directly proportional to the Martian atmospheric density. Employing fiber optics components allows for the lidar multi-functional operation while facilitating a highly efficient, compact and reliable design suitable for integration into a spacecraft with limited mass, size, and power resources
Desensitization of Gonadotropin-releasing Hormone Action in αT3-1 Cells Due to Uncoupling of Inositol 1,4,5-Trisphosphate Generation and Ca 2+ Mobilization
Gonadotropin-releasing hormone (GnRH) acts via a G-protein coupled receptor on gonadotropes to increase cytosolic Ca2+ and stimulate gonadotropin secretion. Sustained exposure causes desensitization of these effects, but the GnRH receptor has no C-terminal tail and does not undergo rapid (<5 min) desensitization. Nevertheless, pretreatment of alphaT3-1 cells with GnRH reduced the spike Ca2+ response to GnRH and decreased the GnRH effect on inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) by 30-50%. Ca2+-free medium with or without thapsigargin also decreased GnRH-stimulated Ins(1,4,5)P3 generation, implying that attenuation of the Ca2+ response underlies the Ins(1,4,5)P3 reduction rather than vice versa. Intracellular Ca2+ pool depletion cannot explain desensitization of the Ca2+ response because pool depletion and repletion were faster (half-times, <1 min) than the onset of and recovery from desensitization (half-times 10-20 min and 4-6 h). Moreover, 1-h GnRH pre-treatment attenuated the spike Ca2+ response to GnRH but not that to ionomycin, and brief GnRH exposure in Ca2+-free medium reduced the response to ionomycin more effectively in controls than in desensitized cells. GnRH pretreatment also attenuated the Ca2+ response to PACAP38. This novel form of desensitization does not reflect uncoupling of GnRH receptors from their immediate effector system but rather a reduced efficiency of mobilization by Ins(1,4,5)P3 of Ca2+ from an intact intracellular pool
The theory of manipulations of pure state asymmetry: basic tools and equivalence classes of states under symmetric operations
If a system undergoes symmetric dynamics, then the final state of the system
can only break the symmetry in ways in which it was broken by the initial
state, and its measure of asymmetry can be no greater than that of the initial
state. It follows that for the purpose of understanding the consequences of
symmetries of dynamics, in particular, complicated and open-system dynamics, it
is useful to introduce the notion of a state's asymmetry properties, which
includes the type and measure of its asymmetry. We demonstrate and exploit the
fact that the asymmetry properties of a state can also be understood in terms
of information-theoretic concepts, for instance in terms of the state's ability
to encode information about an element of the symmetry group. We show that the
asymmetry properties of a pure state psi relative to the symmetry group G are
completely specified by the characteristic function of the state, defined as
chi_psi(g)= where g\in G and U is the unitary representation of
interest. For a symmetry described by a compact Lie group G, we show that two
pure states can be reversibly interconverted one to the other by symmetric
operations if and only if their characteristic functions are equal up to a
1-dimensional representation of the group. Characteristic functions also allow
us to easily identify the conditions for one pure state to be converted to
another by symmetric operations (in general irreversibly) for the various
paradigms of single-copy transformations: deterministic, state-to-ensemble,
stochastic and catalyzed.Comment: Published version. Several new results added. 31 Pages, 3 Figure
Local Tunneling Magnetoresistance probed by Low-Temperature Scanning Laser Microscopy
Tunneling magnetoresistance (TMR) in a vertical manganite junction was
investigated by low-temperature scanning laser microscopy (LTSLM) allowing to
determine the local relative magnetization M orientation of the two electrodes
as a function of magnitude and orientation of the external magnetic field H.
Sweeping the field amplitude at fixed orientation revealed magnetic domain
nucleation and propagation in the junction electrodes. For the high-resistance
state an almost single-domain antiparallel magnetization configuration was
achieved, while in the low-resistance state the junction remained in a
multidomain state. Calculated resistance based on the
local M configuration obtained by LTSLM is in quantitative agreement with R(H)
measured by magnetotransport
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