keyword
MENU ▼
Read by QxMD icon Read
search

space flight

keyword
https://www.readbyqxmd.com/read/29448331/fractional-dynamics-using-an-ensemble-of-classical-trajectories
#1
Zhaopeng Sun, Hao Dong, Yujun Zheng
A trajectory-based formulation for fractional dynamics is presented and the trajectories are generated deterministically. In this theoretical framework, we derive a new class of estimators in terms of confluent hypergeometric function (_{1}F_{1}) to represent the Riesz fractional derivative. Using this method, the simulation of free and confined Lévy flight are in excellent agreement with the exact numerical and analytical results. In addition, the barrier crossing in a bistable potential driven by Lévy noise of index α is investigated...
January 2018: Physical Review. E
https://www.readbyqxmd.com/read/29443900/multisensor-analysis-of-spectral-dimensionality-and-soil-diversity-in-the-great-central-valley-of-california
#2
Daniel Sousa, Christopher Small
Planned hyperspectral satellite missions and the decreased revisit time of multispectral imaging offer the potential for data fusion to leverage both the spectral resolution of hyperspectral sensors and the temporal resolution of multispectral constellations. Hyperspectral imagery can also be used to better understand fundamental properties of multispectral data. In this analysis, we use five flight lines from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) archive with coincident Landsat 8 acquisitions over a spectrally diverse region of California to address the following questions: (1) How much of the spectral dimensionality of hyperspectral data is captured in multispectral data?; (2) Is the characteristic pyramidal structure of the multispectral feature space also present in the low order dimensions of the hyperspectral feature space at comparable spatial scales?; (3) How much variability in rock and soil substrate endmembers (EMs) present in hyperspectral data is captured by multispectral sensors? We find nearly identical partitions of variance, low-order feature space topologies, and EM spectra for hyperspectral and multispectral image composites...
February 14, 2018: Sensors
https://www.readbyqxmd.com/read/29422872/myocardial-ckip-1-overexpression-protects-from-simulated-microgravity-induced-cardiac-remodeling
#3
Shukuan Ling, Yuheng Li, Guohui Zhong, Yongjun Zheng, Qing Xu, Dingsheng Zhao, Weijia Sun, Xiaoyan Jin, Hongxing Li, Jianwei Li, Huiyuan Sun, Dengchao Cao, Jinping Song, Caizhi Liu, Xinxin Yuan, Xiaorui Wu, Yinlong Zhao, Zizhong Liu, Qi Li, Yingxian Li
Human cardiovascular system has adapted to Earth's gravity of 1G. The microgravity during space flight can induce cardiac remodeling and decline of cardiac function. At present, the mechanism of cardiac remodeling induced by microgravity remains to be disclosed. Casein kinase-2 interacting protein-1 (CKIP-1) is an important inhibitor of pressure-overload induced cardiac remodeling by decreasing the phosphorylation level of HDAC4. However, the role of CKIP-1 in the cardiac remodeling induced by microgravity is unknown...
2018: Frontiers in Physiology
https://www.readbyqxmd.com/read/29402092/characterization-of-natural-photonic-crystals-in-iridescent-wings-of-damselfly-chalcopteryx-rutilans-by-fib-sem-tem-and-tof-sims
#4
David M Carr, Ashley A Ellsworth, Gregory L Fisher, Wescley W Valeriano, Juan P Vasco, Paulo S S Guimarães, Rodrigo R de Andrade, Elizabeth R da Silva, Wagner N Rodrigues
The iridescent wings of the Chalcopterix rutilans damselfly (Rambur) (Odonata, Polythoridae) are investigated with focused ion beam/scanning electron microscopy, transmission electron microscopy, and time-of-flight secondary ion mass spectrometry. The electron microscopy images reveal a natural photonic crystal as the source of the varying colors. The photonic crystal has a consistent number and thickness (∼195 nm) of the repeat units on the ventral side of the wing, which is consistent with the red color visible from the bottom side of the wing in all regions...
February 5, 2018: Biointerphases
https://www.readbyqxmd.com/read/29392269/homogeneous-and-heterogeneous-dynamics-in-native-and-denatured-bovine-serum-albumin
#5
Felix Ameseder, Aurel Radulescu, Marina Khaneft, Wiebke Lohstroh, Andreas M Stadler
A characteristic property of unfolded and disordered proteins is their high molecular flexibility, which enables the exploration of a large conformational space. We present neutron scattering experiments on the dynamics of denatured and native folded bovine serum albumin (BSA) in solution. Global protein diffusion and internal macromolecular dynamics were measured using quasielastic neutron time-of-flight and backscattering spectroscopy on the picosecond to nanosecond time- and Ångstrom length-scale. Internal protein dynamics were analysed in a first approach using stretched exponential functions...
February 2, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29388695/microgravity-modulation-of-syncytin-a-expression-enhance-osteoclast-formation
#6
Purushoth Ethiraj, Jessica R Link, James M Sinkway, Gabriella D Brown, William A Parler, Sakamuri V Reddy
Microgravity (µXg) experienced by astronauts during space flights causes accelerated bone loss. However, the molecular basis of µXg induced bone loss in space is unclear. Osteoclast (OCL) is the primary bone-resorbing cell. We previously demonstrated that simulated µXg promotes OCL formation. In this study, we identified that µXg induces syncytin-A expression in RAW264.7 preosteoclast cells without RANKL stimulation. We further tested the effect of osteotropic factors such as CXCL5 and 1,25(OH)2 D3 to regulate the syncytin-A expression in preosteoclast cells subjected to µXg compared to ground based (Xg) cultures...
February 1, 2018: Journal of Cellular Biochemistry
https://www.readbyqxmd.com/read/29386519/a-diverse-mammal-dominated-footprint-assemblage-from-wetland-deposits-in-the-lower-cretaceous-of-maryland
#7
Ray Stanford, Martin G Lockley, Compton Tucker, Stephen Godfrey, Sheila M Stanford
A newly discovered assemblage of predominantly small tracks from the Cretaceous Patuxent Formation at NASA's Goddard Space Flight Center, Maryland, reveals one of the highest track densities and diversities ever reported (~70 tracks, representing at least eight morphotypes from an area of only ~2 m2). The assemblage is dominated by small mammal tracks including the new ichnotxon Sederipes goddardensis, indicating sitting postures. Small crow-sized theropod trackways, the first from this unit, indicate social trackmakers and suggest slow-paced foraging behavior...
January 31, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29385059/multichannel-high-resolution-wide-swath-sar-imaging-for-hypersonic-air-vehicle-with-curved-trajectory
#8
Rui Zhou, Jinping Sun, Yuxin Hu, Yaolong Qi
Synthetic aperture radar (SAR) equipped on the hypersonic air vehicle in near space has many advantages over the conventional airborne SAR. However, its high-speed maneuvering characteristics with curved trajectory result in serious range migration, and exacerbate the contradiction between the high resolution and wide swath. To solve this problem, this paper establishes the imaging geometrical model matched with the flight trajectory of the hypersonic platform and the multichannel azimuth sampling model based on the displaced phase center antenna (DPCA) technology...
January 31, 2018: Sensors
https://www.readbyqxmd.com/read/29361412/prevalence-of-propionibacterium-acnes-in-the-glenohumeral-compared-with-the-subacromial-space-in-primary-shoulder-arthroscopies
#9
Thilo Patzer, Sabine Petersdorf, Ruediger Krauspe, Pablo Emilio Verde, Birgit Henrich, Martin Hufeland
HYPOTHESIS: We hypothesized that the prevalence of Propionibacterium acnes in patients undergoing primary shoulder arthroscopy is equal in the glenohumeral space compared with the subacromial space. METHODS: Patients aged 18 years or older with shoulder arthroscopies were included. The exclusion criteria were prior shoulder operations, complete rotator cuff tears, systemic inflammatory diseases, tumors, shoulder injections within 6 months of surgery, and antibiotic therapy within 14 days preoperatively...
January 18, 2018: Journal of Shoulder and Elbow Surgery
https://www.readbyqxmd.com/read/29347028/continuous-time-random-walk-model-for-anomalous-diffusion-in-expanding-media
#10
F Le Vot, E Abad, S B Yuste
Expanding media are typical in many different fields, e.g., in biology and cosmology. In general, a medium expansion (contraction) brings about dramatic changes in the behavior of diffusive transport properties such as the set of positional moments and the Green's function. Here, we focus on the characterization of such effects when the diffusion process is described by the continuous-time random-walk (CTRW) model. As is well known, when the medium is static this model yields anomalous diffusion for a proper choice of the probability density function (pdf) for the jump length and the waiting time, but the behavior may change drastically if a medium expansion is superimposed on the intrinsic random motion of the diffusing particle...
September 2017: Physical Review. E
https://www.readbyqxmd.com/read/29341784/fractional-transport-in-strongly-turbulent-plasmas
#11
Heinz Isliker, Loukas Vlahos, Dana Constantinescu
We analyze statistically the energization of particles in a large scale environment of strong turbulence that is fragmented into a large number of distributed current filaments. The turbulent environment is generated through strongly perturbed, 3D, resistive magnetohydrodynamics simulations, and it emerges naturally from the nonlinear evolution, without a specific reconnection geometry being set up. Based on test-particle simulations, we estimate the transport coefficients in energy space for use in the classical Fokker-Planck (FP) equation, and we show that the latter fails to reproduce the simulation results...
July 28, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29334405/high-resolution-dental-mri-for-planning-palatal-graft-surgery-a-clinical-pilot-study
#12
Tim Hilgenfeld, Thorsten Kästel, Alexander Heil, Peter Rammelsberg, Sabine Heiland, Martin Bendszus, Franz Sebastian Schwindling
AIM: To evaluate whether high-resolution, non-contrast-enhanced dental MRI can be used for accurate determination of palatal-masticatory-mucosa-thickness (PMMT) and to locate the greater palatal artery (GPA). MATERIALS AND METHODS: In five volunteers (4 males, 1 female; mean age 30.2±0.4 years) two independent raters measured PMMT by use of dental MRI in 180 positions. For comparison, clinical bone sounding was performed. The GPA was identified in time-of-flight (TOF) angiography and MSVAT-SPACE-prototype sequence...
January 15, 2018: Journal of Clinical Periodontology
https://www.readbyqxmd.com/read/29332382/cu2i2se6-a-metal-inorganic-framework-wide-bandgap-semiconductor-for-photon-detection-at-room-temperature
#13
Wenwen Lin, Constantinos C Stoumpos, Oleg Y Kontsevoi, Zhifu Liu, Yihui He, Sanjib Das, Yadong Xu, Kyle M McCall, Bruce W Wessels, Mercouri G Kanatzidis
Cu2I2Se6 is a new wide-bandgap semiconductor with high stability and great potential towards hard radiation and photon detection. Cu2I2Se6 crystallizes in the rhombohedral R3 ̅m space group with a density of d = 5.287 g·cm-3 and a wide bandgap Eg of 1.95 eV. First-principles electronic band structure calculations at the density functional theory level indicate an indirect bandgap and a low electron effective mass me* of 0.32. The congruently melting compound was grown in centimeter-size Cu2I2Se6 single crystals using a vertical Bridgman method...
January 14, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29328339/reduced-sintering-of-mass-selected-au-clusters-on-sio2-by-alloying-with-ti-an-aberration-corrected-stem-and-computational-study
#14
Yubiao Niu, Philomena Schlexer, Bela Sebok, Ib Chorkendorff, Gianfranco Pacchioni, Richard E Palmer
Au nanoparticles represent the most remarkable example of a size effect in heterogeneous catalysis. However, a major issue hindering the use of Au nanoparticles in technological applications is their rapid sintering. We explore the potential of stabilizing Au nanoclusters on SiO2 by alloying them with a reactive metal, Ti. Mass-selected Au/Ti clusters (400 000 amu) and Au2057 clusters (405 229 amu) were produced with a magnetron sputtering, gas condensation cluster beam source in conjunction with a lateral time-of-flight mass filter, deposited onto a silica support and characterised by XPS and LEIS...
January 12, 2018: Nanoscale
https://www.readbyqxmd.com/read/29327266/social-targets-improve-body-based-and-environment-based-strategies-during-spatial-navigation
#15
Esther Kuehn, Xiaoli Chen, Pia Geise, Jan Oltmer, Thomas Wolbers
Encoding the position of another person in space is vital for everyday life. Nevertheless, little is known about the specific navigational strategies associated with encoding the position of another person in the wider spatial environment. We asked two groups of participants to learn the location of a target (person or object) during active navigation, while optic flow information, a landmark, or both optic flow information and a landmark were available in a virtual environment. Whereas optic flow information is used for body-based encoding, such as the simulation of motor movements, landmarks are used to form an abstract, disembodied representation of the environment...
January 11, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/29327046/ocular-coherence-tomographic-analysis-of-the-optic-nerve-head-and-surrounding-structures-in-space-flight-associated-neuro-ocular-syndrome
#16
Andrew G Lee
No abstract text is available yet for this article.
January 11, 2018: JAMA Ophthalmology
https://www.readbyqxmd.com/read/29316459/a-discrete-particle-model-reproducing-collective-dynamics-of-a-bee-swarm
#17
Sara Bernardi, Annachiara Colombi, Marco Scianna
In this article, we present a microscopic discrete mathematical model describing collective dynamics of a bee swarm. More specifically, each bee is set to move according to individual strategies and social interactions, the former involving the desire to reach a target destination, the latter accounting for repulsive/attractive stimuli and for alignment processes. The insects tend in fact to remain sufficiently close to the rest of the population, while avoiding collisions, and they are able to track and synchronize their movement to the flight of a given set of neighbors within their visual field...
January 2, 2018: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/29290633/sam-caam-a-concept-for-acquiring-systematic-aircraft-measurements-to-characterize-aerosol-air-masses
#18
Ralph A Kahn, Tim A Berkoff, Charles Brock, Gao Chen, Richard A Ferrare, Steven Ghan, Thomas F Hansico, Dean A Hegg, J Vanderlei Martins, Cameron S McNaughton, Daniel M Murphy, John A Ogren, Joyce E Penner, Peter Pilewskie, John H Seinfeld, Douglas R Worsnop
A modest operational program of systematic aircraft measurements can resolve key satellite-aerosol-data-record limitations. Satellite observations provide frequent, global aerosol-amount maps, but offer only loose aerosol property constraints needed for climate and air quality applications. We define and illustrate the feasibility of flying an aircraft payload to measure key aerosol optical, microphysical, and chemical properties in situ. The flight program could characterize major aerosol air-mass types statistically, at a level-of-detail unobtainable from space...
October 2017: Bulletin of the American Meteorological Society
https://www.readbyqxmd.com/read/29286496/evoked-bioelectrical-brain-activity-following-exposure-to-ionizing-radiation
#19
K Loganovsky, K Kuts
The article provides an overview of modern physiological evidence to support the hypothesis on cortico limbic sys tem dysfunction due to the hippocampal neurogenesis impairment as a basis of the brain interhemispheric asym metry and neurocognitive deficit after radiation exposure. The importance of the research of both evoked poten tials and fields as a highly sensitive and informative method is emphasized.Particular attention is paid to cerebral sensor systems dysfunction as a typical effect of ionizing radiation...
December 2017: Problemy Radiat︠s︡iĭnoï Medyt︠s︡yny Ta Radiobiolohiï
https://www.readbyqxmd.com/read/29282870/chemical-profiling-of-bioactive-constituents-in-hop-cones-and-pellets-extracts-by-online-comprehensive-two-dimensional-liquid-chromatography-with-tandem-mass-spectrometry-and-direct-infusion-fourier-transform-ion-cyclotron-resonance-mass-spectrometry
#20
Eduardo Sommella, Francesco Pagano, Emanuela Salviati, Marcello Chieppa, Alessia Bertamino, Michele Manfra, Marina Sala, Ettore Novellino, Pietro Campiglia
Humulus Lupulus L. (hop) is highly interesting from a nutraceutical perspective. The hop phytocomplex contains a wide range of bioactive metabolites, and its characterization is challenging. To tackle such a task, we applied and compared for the first time a combined approach consisting of online comprehensive two dimensional liquid chromatography with tandem mass spectrometry and direct infusion Fourier transform ion cyclotron mass spectrometry. A reversed phase × reversed phase approach with a shifted gradient in the second dimension ensured selectivity and two dimensional space coverage...
December 28, 2017: Journal of Separation Science
keyword
keyword
45383
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"