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https://www.readbyqxmd.com/read/28618521/local-time-of-l%C3%A3-vy-random-walks-a-path-integral-approach
#1
Václav Zatloukal
The local time of a stochastic process quantifies the amount of time that sample trajectories x(τ) spend in the vicinity of an arbitrary point x. For a generic Hamiltonian, we employ the phase-space path-integral representation of random walk transition probabilities in order to quantify the properties of the local time. For time-independent systems, the resolvent of the Hamiltonian operator proves to be a central tool for this purpose. In particular, we focus on the local times of Lévy random walks (Lévy flights), which correspond to fractional diffusion equations...
May 2017: Physical Review. E
https://www.readbyqxmd.com/read/28590761/proteome-wide-adaptations-of-mouse-skeletal-muscles-during-a-full-month-in-space
#2
Georg Tascher, Thomas Brioche, Pauline Maes, Angèle Chopard, Donal O'Gorman, Guillemette Gauquelin-Koch, Stephane Blanc, Fabrice Bertile
The safety of space flight is challenged by a severe loss of skeletal muscle mass, strength and endurance that may compromise the health and performance of astronauts. The molecular mechanisms underpinning muscle atrophy and decreased performance have been studied mostly after short duration flights, and are still not fully elucidated. By deciphering the muscle proteome changes elicited in mice after a full month aboard the BION-M1 biosatellite, we observed that the antigravity soleus incurred the greatest changes compared to locomotor muscles...
June 7, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28587778/advanced-method-optimization-for-volatile-aroma-profiling-of-beer-using-two-dimensional-gas-chromatography-time-of-flight-mass-spectrometry
#3
Pierre-Hugues Stefanuto, Katelynn A Perrault, Lena M Dubois, Benjamin L'Homme, Catherine Allen, Caitriona Loughnane, Nobuo Ochiai, Jean-François Focant
The complex mixture of volatile organic compounds (VOCs) present in the headspace of Trappist and craft beers was studied to illustrate the efficiency of thermal desorption (TD) comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) for highlighting subtle differences between highly complex mixtures of VOCs. Headspace solid-phase microextraction (HS-SPME), multiple (and classical) stir bar sorptive extraction (mSBSE), static headspace (SHS), and dynamic headspace (DHS) were compared for the extraction of a set of 21 representative flavor compounds of beer aroma...
June 1, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28587174/chang-e-5t-orbit-determination-using-onboard-gps-observations
#4
Xing Su, Tao Geng, Wenwen Li, Qile Zhao, Xin Xie
In recent years, Global Navigation Satellite System (GNSS) has played an important role in Space Service Volume, the region enclosing the altitudes above 3000 km up to 36,000 km. As an in-flight test for the feasibility as well as for the performance of GNSS-based satellite orbit determination (OD), the Chinese experimental lunar mission Chang'E-5T had been equipped with an onboard high-sensitivity GNSS receiver with GPS and GLONASS tracking capability. In this contribution, the 2-h onboard GPS data are evaluated in terms of tracking performance as well as observation quality...
June 1, 2017: Sensors
https://www.readbyqxmd.com/read/28586223/in-situ-neutron-diffraction-studies-of-ion-exchange-synthesis-mechanism-of-li2mg2p3o9n-evidence-for-hidden-phase-transition
#5
Jue Liu, Pamela S Whitfield, Michael R Saccomanno, Shou-Hang Bo, Enyuan Hu, Xiqian Yu, Jianming Bai, Clare P Grey, Xiao-Qing Yang, Peter G Khalifah
Motivated by predictions made using a bond valence sum difference map (BVS-DM) analysis, the novel Li-ion conductor Li2Mg2P3O9N was synthesized by ion exchange from a Na2Mg2P3O9N precursor. Impedance spectroscopy measurements indicate that Li2Mg2P3O9N has a room temperature Li-ion conductivity of about 10-6 S/cm (comparable to LiPON) which is six orders of magnitude higher than the extrapolated Na-ion conductivity of Na2Mg2P3O9N at this temperature. The structure of Li2Mg2P3O9N was determined from ex situ synchrotron and time-of-flight neutron diffraction data to retain the P213 space group, though with a cubic lattice parameter of a = 9...
June 6, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28580400/replacement-of-daily-load-attenuates-but-does-not-prevent-changes-to-the-musculoskeletal-system-during-bed-rest
#6
Peter R Cavanagh, Andrea J Rice, Sara C Novotny, Kerim O Genc, Ricki K Englehaupt, Tammy M Owings, Bryan Comstock, Tamre Cardoso, Hakan Ilaslan, Scott M Smith, Angelo A Licata
The dose-response effects of exercise in reduced gravity on musculoskeletal health have not been well documented. It is not known whether or not individualized exercise prescriptions can be effective in preventing the substantial loss in bone mineral density and muscle function that have been observed in space flight and in bed rest. In this study, typical daily loads to the lower extremities were quantified in free-living subjects who were then randomly assigned to control or exercise groups. Subjects were confined to 6-degree head-down bed rest for 84 days...
December 2016: Bone Reports
https://www.readbyqxmd.com/read/28574653/cortical-and-trabecular-bone-microstructure-did-not-recover-at-weight-bearing-skeletal-sites-and-progressively-deteriorated-at-non-weight-bearing-sites-during-the-year-following-international-space-station-missions
#7
Laurence Vico, Bert Van Rietbergen, Nicolas Vilayphiou, Marie-Thérèse Linossier, Hervé Locrelle, Myriam Normand, Mohamed Zouch, Maude Gerbaix, Nicolas Bonnet, Valery Novikov, Thierry ThomC, Galina Vassilieva
Risk for premature osteoporosis is a major health concern in astronauts and cosmonauts and the reversibility of the bone lost at the weight-bearing bone sites is not established although it is suspected to take longer than the mission length. The bone three-dimensional structure and strength which could be uniquely affected by weightlessness, is currently unknown. Our objective is to evaluate bone mass, microarchitecture and strength of weight- and non-weight-bearing bone in 13 cosmonauts before and for 12 months after 4-6-month sojourn in the International Space Station (ISS)...
June 2, 2017: Journal of Bone and Mineral Research: the Official Journal of the American Society for Bone and Mineral Research
https://www.readbyqxmd.com/read/28571326/anomalous-barrier-escape-the-roles-of-noise-distribution-and-correlation
#8
Meng Hu, Jia-Ming Zhang, Jing-Dong Bao
We study numerically and analytically the barrier escape dynamics of a particle driven by an underlying correlated Lévy noise for a smooth metastable potential. A "quasi-monochrome-color" Lévy noise, i.e., the first-order derivative variable of a linear second-order differential equation subjected to a symmetric α-stable white Lévy noise, also called the harmonic velocity Lévy noise, is proposed. Note that the time-integral of the noise Green function of this kind is equal to zero. This leads to the existence of underlying negative time correlation and implies that a step in one direction is likely followed by a step in the other direction...
May 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28554506/bion-m-1-first-continuous-blood-pressure-monitoring-in-mice-during-a-30-day-spaceflight
#9
Alexander Andreev-Andrievskiy, Anfisa Popova, Jean-Christophe Lloret, Patrick Aubry, Anatoliy Borovik, Daria Tsvirkun, Olga Vinogradova, Eugeniy Ilyin, Guillemette Gauquelin-Koch, Claude Gharib, Marc-Antoine Custaud
Animals are an essential component of space exploration and have been used to demonstrate that weightlessness does not disrupt essential physiological functions. They can also contribute to space research as models of weightlessness-induced changes in humans. Animal research was an integral component of the 30-day automated Russian biosatellite Bion-M 1 space mission. The aim of the hemodynamic experiment was to estimate cardiovascular function in mice, a species roughly 3000 times smaller than humans, during prolonged spaceflight and post-flight recovery, particularly, to investigate if mice display signs of cardiovascular deconditioning...
May 2017: Life Sciences in Space Research
https://www.readbyqxmd.com/read/28553233/coherent-multimodal-sensory-information-allows-switching-between-gravitoinertial-contexts
#10
Marie Barbiero, Célia Rousseau, Charalambos Papaxanthis, Olivier White
Whether the central nervous system is capable to switch between contexts critically depends on experimental details. Motor control studies regularly adopt robotic devices to perturb the dynamics of a certain task. Other approaches investigate motor control by altering the gravitoinertial context itself as in parabolic flights and human centrifuges. In contrast to conventional robotic experiments, where only the hand is perturbed, these gravitoinertial or immersive settings coherently plunge participants into new environments...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28541523/attraction-of-the-euwallacea-sp-near-fornicatus-coleoptera-curculionidae-to-quercivorol-and-to-infestations-in-avocado
#11
John A Byers, Yonatan Maoz, Anat Levi-Zada
The Euwallacea sp. near fornicatus (Euwallacea sp. 1 hereafter) feeds on many woody shrubs and trees and is a pest of avocado, Persea americana Mill., in several countries including Israel and the United States. Quercivorol baits are commercially available for Euwallacea sp. 1 females (males do not fly), but their attractive strength compared to other pheromones and potential for mass trapping are unknown. We used sticky traps baited with quercivorol released at 0.126 mg/d (1×) and at 0.01×, 0.1×, and 10× relative rates to obtain a dose-response curve of Euwallacea sp...
May 24, 2017: Journal of Economic Entomology
https://www.readbyqxmd.com/read/28540482/linear-sign-in-cystic-brain-lesions-%C3%A2-5-mm-a-suggestive-feature-of-perivascular-space
#12
Jinkyeong Sung, Jinhee Jang, Hyun Seok Choi, So-Lyung Jung, Kook-Jin Ahn, Bum-Soo Kim
OBJECTIVE: To determine the prevalence of a linear sign within enlarged perivascular space (EPVS) and chronic lacunar infarction (CLI) ≥ 5 mm on T2-weighted imaging (T2WI) and time-of-flight (TOF) magnetic resonance angiography (MRA), and to evaluate the diagnostic value of the linear signs for EPVS over CLI. METHODS: This study included 101 patients with cystic lesions ≥ 5 mm on brain MRI including TOF MRA. After classification of cystic lesions into EPVS or CLI, two readers assessed linear signs on T2WI and TOF MRA...
May 24, 2017: European Radiology
https://www.readbyqxmd.com/read/28539140/hemoglobin-oxygen-saturation-with-mild-hypoxia-and-microgravity
#13
Johnny Conkin, James H Wessel, Jason R Norcross, Omar S Bekdash, Andrew F J Abercromby, Matthew D Koslovsky, Michael L Gernhardt
INTRODUCTION: Microgravity (μG) exposure and even early recovery from μG in combination with mild hypoxia may increase the alveolar-arterial oxygen (O2) partial pressure gradient. METHODS: Four male astronauts on STS-69 (1995) and four on STS-72 (1996) were exposed on Earth to an acute sequential hypoxic challenge by breathing for 4 min 18.0%, 14.9%, 13.5%, 12.9%, and 12.2% oxygen-balance nitrogen. The 18.0% O2 mixture at sea level resulted in an inspired O2 partial pressure (PIo2) of 127 mmHg...
June 1, 2017: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/28535935/qualitative-analyses-of-less-volatile-organic-molecules-from-female-skin-scents-by-comprehensive-two-dimensional-gas-chromatography-time-of-flight-mass-spectrometry
#14
Petr Doležal, Pavlína Kyjaková, Irena Valterová, Štěpán Urban
Instrumental human scent analysis is undoubtedly desirable for many forensic as well medical applications. Most of the previous human scent studies were focused on volatile organic compounds (VOCs) which were analysed by head space solid phase micro-extraction gas chromatography/mass spectrometry (HS-SPME-GC/MS). This method is, however, significantly less sensitive to "heavier" less volatile compounds emitted from the human skin. These less volatile organic scent molecules probably create the basis of the individual human scent signature, and therefore, our attention is focused mainly on these "heavier" compounds...
May 1, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28529490/microgravity-induced-transcriptome-adaptation-in-mouse-paraspinal-longissimus-dorsi-muscle-highlights-insulin-resistance-linked-genes
#15
Guido Gambara, Michele Salanova, Stefano Ciciliot, Sandra Furlan, Martina Gutsmann, Gudrun Schiffl, Ute Ungethuem, Pompeo Volpe, Hanns-Christian Gunga, Dieter Blottner
Microgravity as well as chronic muscle disuse are two causes of low back pain originated at least in part from paraspinal muscle deconditioning. At present no study investigated the complexity of the molecular changes in human or mouse paraspinal muscles exposed to microgravity. The aim of this study was to evaluate longissimus dorsi adaptation to microgravity at both morphological and global gene expression level. C57BL/N6 male mice were flown aboard the BION-M1 biosatellite for 30 days (BF) or housed in a replicate flight habitat on ground (BG)...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28518086/ptr-tof-ms-coupled-with-an-automated-sampling-system-and-tailored-data-analysis-for-food-studies-bioprocess-monitoring-screening-and-nose-space-analysis
#16
Vittorio Capozzi, Sine Yener, Iuliia Khomenko, Brian Farneti, Luca Cappellin, Flavia Gasperi, Matteo Scampicchio, Franco Biasioli
Proton Transfer Reaction (PTR), combined with a Time-of-Flight (ToF) Mass Spectrometer (MS) is an analytical approach based on chemical ionization that belongs to the Direct-Injection Mass Spectrometric (DIMS) technologies. These techniques allow the rapid determination of volatile organic compounds (VOCs), assuring high sensitivity and accuracy. In general, PTR-MS requires neither sample preparation nor sample destruction, allowing real time and non-invasive analysis of samples. PTR-MS are exploited in many fields, from environmental and atmospheric chemistry to medical and biological sciences...
May 11, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28505754/generalized-balance-equations-for-charged-particle-transport-via-localized-and-delocalized-states-mobility-generalized-einstein-relations-and-fractional-transport
#17
Peter W Stokes, Bronson Philippa, Daniel Cocks, Ronald D White
A generalized phase-space kinetic Boltzmann equation for highly nonequilibrium charged particle transport via localized and delocalized states is used to develop continuity, momentum, and energy balance equations, accounting explicitly for scattering, trapping and detrapping, and recombination loss processes. Analytic expressions detail the effect of these microscopic processes on mobility and diffusivity. Generalized Einstein relations (GER) are developed that enable the anisotropic nature of diffusion to be determined in terms of the measured field dependence of the mobility...
April 2017: Physical Review. E
https://www.readbyqxmd.com/read/28503167/the-impact-of-space-flight-on-survival-and-interaction-of-cupriavidus-metallidurans-ch34-with-basalt-a-volcanic-moon-analog-rock
#18
Bo Byloos, Ilse Coninx, Olivier Van Hoey, Charles Cockell, Natasha Nicholson, Vyacheslav Ilyin, Rob Van Houdt, Nico Boon, Natalie Leys
Microbe-mineral interactions have become of interest for space exploration as microorganisms could be used to biomine from extra-terrestrial material and extract elements useful as micronutrients in life support systems. This research aimed to identify the impact of space flight on the long-term survival of Cupriavidus metallidurans CH34 in mineral water and the interaction with basalt, a lunar-type rock in preparation for the ESA spaceflight experiment, BIOROCK. Therefore, C. metallidurans CH34 cells were suspended in mineral water supplemented with or without crushed basalt and send for 3 months on board the Russian FOTON-M4 capsule...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28496012/daytime-behavior-of-pteropus-vampyrus-in-a-natural-habitat-the-driver-of-viral-transmission
#19
Yupadee Hengjan, Didik Pramono, Hitoshi Takemae, Ryosuke Kobayashi, Keisuke Iida, Takeshi Ando, Supratikno Supratikno, Chaerul Basri, Yuli Sulistya Fitriana, Eko M Z Arifin, Yasushige Ohmori, Ken Maeda, Srihadi Agungpriyono, Eiichi Hondo
Flying foxes, the genus Pteropus are considered viral reservoirs. Their colonial nature and long flight capability enhance their ability to spread viruses quickly. To understand how the viral transmission occurs between flying foxes and other animals, we investigated daytime behavior of the large flying fox (Pteropus vampyrus) in the Leuweung Sancang conservation area, Indonesia, by using instantaneous scan sampling and all occurrence focal sampling. The data were obtained from 0700 to 1700 hr, during May 11-25, 2016...
May 12, 2017: Journal of Veterinary Medical Science
https://www.readbyqxmd.com/read/28495841/lower-body-negative-pressure-decreases-non-invasively-measured-intracranial-pressure-and-internal-jugular-vein-cross-sectional-area-during-head-down-tilt
#20
William Watkins, Alan R Hargens, Shannon Baird, Erika Marie Clary, Brandon R Macias
INTRODUCTION: Long-term space flight induces a near visual acuity change in approximately 50% of astronauts. In some crew members, postflight cerebrospinal fluid (CSF) opening pressures by lumbar puncture are as high as 20.9 mmHg who demonstrated optic disc edema. CSF communicates through the cochlear aqueduct to affect perilymphatic pressure and tympanic membrane motion. We hypothesized that 50 mmHg of lower-body negative pressure (LBNP) during 15° head-down tilt (HDT) would mitigate elevations in internal jugular vein cross-sectional area (IJV CSA) and intracranial pressure (ICP)...
May 11, 2017: Journal of Applied Physiology
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