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Cosmic Radiation

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https://www.readbyqxmd.com/read/29396427/10be-inferred-paleo-denudation-rates-imply-that-the-mid-miocene-western-central-andes-eroded-as-slowly-as-today
#1
Andrea Madella, Romain Delunel, Naki Akçar, Fritz Schlunegger, Marcus Christl
Terrestrial cosmogenic nuclide concentrations of detrital minerals yield catchment-wide rates at which hillslopes erode. These estimates are commonly used to infer millennial scale denudation patterns and to identify the main controls on mass-balance and landscape evolution at orogenic scale. The same approach can be applied to minerals preserved in stratigraphic records of rivers, although extracting reliable paleo-denudation rates from Ma-old archives can be limited by the target nuclide's half-life and by exposure to cosmic radiations after deposition...
February 2, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29378015/determination-of-the-response-to-the-atmospheric-cosmic-radiation-of-a-neutron-dosimeter-assisted-by-monte-carlo-simulation
#2
M A Pereira, C A Federico, O L Gonçalez
A TLD-based dosimeter of polyethylene-lead-polyethylene, was developed and characterized with Monte Carlo simulations, using the MCNPX code. This passive system for the determination of the ambient dose equivalent (H*(10)) for neutrons over a wide energy range can be used for the dosimetry of neutrons from atmospheric cosmic radiation, on the ground, and onboard aircraft. A method assisted by Monte Carlo simulations that improves the calibration of fast neutron dosimeters based on moderation and thermalization of the incident fast flux and the measurement of the thermal flux by a sensor, which respond mainly to thermal neutrons, is presented in this work...
January 25, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29358356/signatures-of-higgs-dilaton-and-critical-higgs-inflation
#3
Juan García-Bellido
We test the Higgs dilaton inflation model (HDM) using the latest cosmological datasets, including the cosmic microwave background temperature, polarization and lensing data from the Planck satellite (2015), the BICEP and Keck Array experiments, the type Ia supernovae from the JLA catalogue, the baryon acoustic oscillations from CMASS, LOWZ and 6dF, the weak lensing data from the CFHTLenS survey and the matter power spectrum measurements from the latest SDSS data release. We find that the values of all cosmological parameters allowed by the HDM are well within the Planck satellite (2015) constraints...
March 6, 2018: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/29356279/on-the-synthesis-of-chocolate-flavonoids-propanols-butanals-in-the-interstellar-medium
#4
Matthew James Abplanalp, Sándor Góbi, Alexandre Bergantini, Andrew M Turner, Ralf I Kaiser
Complex organic molecules are ubiquitous in star- and planet-forming regions as well as on comets such as on 67P/Churyumov-Gerasimenko, but their origins have remained largely unexplained until now. Here, we report the first laboratory detection of distinct C3H8O (propanol, methyl ethyl ether) and C4H8O (n-butanal, i-butanal) isomers formed within interstellar analog ices through interaction with ionizing radiation. This study reveals that complex organics with propyl (C3H7) and butyl (C4H9) groups can be synthesized easily in deep space and may act as key evolutionary tracers of a cosmic ray driven non-equilibrium chemistry in low temperature interstellar ices at 10 K...
January 22, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/29335452/chaotic-universe-model
#5
Ekrem Aydiner
In this study, we consider nonlinear interactions between components such as dark energy, dark matter, matter and radiation in the framework of the Friedman-Robertson-Walker space-time and propose a simple interaction model based on the time evolution of the densities of these components. By using this model we show that these interactions can be given by Lotka-Volterra type equations. We numerically solve these coupling equations and show that interaction dynamics between dark energy-dark matter-matter or dark energy-dark matter-matter-radiation has a strange attractor for 0 > w de  >-1, w dm  ≥ 0, w m  ≥ 0 and w r  ≥ 0 values...
January 15, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29328192/near-quantum-noise-limited-and-absolute-frequency-stabilized-1083%C3%A2-%C3%A2-nm-single-frequency-fiber-laser
#6
Qilai Zhao, Kaijun Zhou, Zisheng Wu, Changsheng Yang, Zhouming Feng, Huihui Cheng, Jiulin Gan, Mingying Peng, Zhongmin Yang, Shanhui Xu
The Earth's magnetic field has significant effects that protect us from cosmic radiation and provide navigation for biological migration. However, slow temporal variations originating in the liquid outer core invariably exist. To understand the working mechanism of the geomagnetic field and improve accuracy of navigation systems, a high-precision magnetometer is essential to measure the absolute magnetic field. A helium optically pumping magnetometer is an advanced approach, but its sensitivity and accuracy are directly limited by the low-frequency relative intensity noise and frequency stability characteristics of a light source...
January 1, 2018: Optics Letters
https://www.readbyqxmd.com/read/29296044/comments-on-radiological-risk-assessment-of-cosmic-radiation-at-aviation-altitudes-a-trip-from-houston-intercontinental-airport-to-lagos-international-airport
#7
Munish Kumar, D Datta
No abstract text is available yet for this article.
October 2017: Journal of Medical Physics
https://www.readbyqxmd.com/read/29286257/synergy-theory-in-radiobiology
#8
Dae Woong Ham, Binglin Song, Jian Gao, Julien Yu, Rainer K Sachs
Customized open-source software is used to characterize, exemplify, compare and critically evaluate mathematical/computational synergy analysis methods currently used in biology, and used or potentially applicable in radiobiology. As examples, we reanalyze some published results on murine Harderian gland tumors and on in vitro chromosome aberrations induced by exposure to single-ion radiations that simulate components of the galactic cosmic ray field. Baseline no-synergy/no-antagonism-mixture dose-effect relationships are calculated for corresponding mixed fields...
December 29, 2017: Radiation Research
https://www.readbyqxmd.com/read/29236693/measurement-of-electrons-from-albedo-neutron-decay-and-neutron-density-in-near-earth-space
#9
Xinlin Li, Richard Selesnick, Quintin Schiller, Kun Zhang, Hong Zhao, Daniel N Baker, Michael A Temerin
The Galaxy is filled with cosmic-ray particles, mostly protons with kinetic energies greater than hundreds of megaelectronvolts. Around Earth, trapped energetic protons, electrons and other particles circulate at altitudes from about 500 to 40,000 kilometres in the Van Allen radiation belts. Soon after these radiation belts were discovered six decades ago, it was recognized that the main source of inner-belt protons (with kinetic energies of tens to hundreds of megaelectronvolts) is cosmic-ray albedo neutron decay (CRAND)...
December 13, 2017: Nature
https://www.readbyqxmd.com/read/29233237/medical-implications-of-space-radiation-exposure-due-to-low-altitude-polar-orbits
#10
Jeffery C Chancellor, Serena M Auñon-Chancellor, John Charles
INTRODUCTION: Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and solar particle events (SPEs) may pose a critical health risk to future spaceflight crews and can have a serious impact on all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960s Manned Orbiting Laboratory (MOL) program's space vehicle and the high inclination polar orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity...
January 1, 2018: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/29206597/quantitative-proteomic-analysis-of-the-hippocampus-of-rats-with-gcr-induced-spatial-memory-impairment
#11
Sucharita M Dutta, Melissa M Hadley, Scott Peterman, Jessica S Jewell, Vania D Duncan, Richard A Britten
NASA is planning future missions to Mars, which will result in astronauts being exposed to ∼13 cGy/year of galactic cosmic radiation (GCR). Previous ground-based experiments have demonstrated that low (15 cGy) doses of 1 GeV/n 56Fe ions impair hippocampus-dependent spatial memory in rats. However, some irradiated rats maintain a spatial memory performance comparable to that seen in the sham-irradiated rats, suggesting that some of these animals are able to ameliorate the deleterious effects of the GCR, while others are not...
December 5, 2017: Radiation Research
https://www.readbyqxmd.com/read/29198317/effects-of-high-intensity-static-magnetic-fields-on-a-root-based-bioreactor-system-for-space-applications
#12
Maria Elena Villani, Silvia Massa, Vanni Lopresto, Rosanna Pinto, Anna Maria Salzano, Andrea Scaloni, Eugenio Benvenuto, Angiola Desiderio
Static magnetic fields created by superconducting magnets have been proposed as an effective solution to protect spacecrafts and planetary stations from cosmic radiations. This shield can deflect high-energy particles exerting injurious effects on living organisms, including plants. In fact, plant systems are becoming increasingly interesting for space adaptation studies, being useful not only as food source but also as sink of bioactive molecules in future bioregenerative life-support systems (BLSS). However, the application of protective magnetic shields would generate inside space habitats residual magnetic fields, of the order of few hundreds milli Tesla, whose effect on plant systems is poorly known...
November 2017: Life Sciences in Space Research
https://www.readbyqxmd.com/read/29198311/comparison-of-methods-for-individualized-astronaut-organ-dosimetry-morphometry-based-phantom-library-versus-body-contour-autoscaling-of-a-reference-phantom
#13
Michelle M Sands, David Borrego, Matthew R Maynard, Amir A Bahadori, Wesley E Bolch
One of the hazards faced by space crew members in low-Earth orbit or in deep space is exposure to ionizing radiation. It has been shown previously that while differences in organ-specific and whole-body risk estimates due to body size variations are small for highly-penetrating galactic cosmic rays, large differences in these quantities can result from exposure to shorter-range trapped proton or solar particle event radiations. For this reason, it is desirable to use morphometrically accurate computational phantoms representing each astronaut for a risk analysis, especially in the case of a solar particle event...
November 2017: Life Sciences in Space Research
https://www.readbyqxmd.com/read/29165652/studies-of-cosmic-ray-muons-and-neutrons-in-a-five-story-concrete-building
#14
Wei-Lin Chen, Rong-Jiun Sheu
This study thoroughly determined the flux and dose rate distributions of cosmic-ray muons and neutrons in a five-story concrete building by comparing measurements with Monte Carlo simulations of cosmic-ray showers. An angular-energy-dependent surface source comprising secondary muons and neutrons at a height of 200 m above ground level was established and verified, which was used to concatenate the shower development in the upper atmosphere with subsequent simulations of radiation transport down to ground level, including the effect of the terrain and studied building...
November 18, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29156538/combined-effects-of-simulated-microgravity-and-radiation-exposure-on-osteoclast-cell-fusion
#15
Srinivasan Shanmugarajan, Ye Zhang, Maria Moreno-Villanueva, Ryan Clanton, Larry H Rohde, Govindarajan T Ramesh, Jean D Sibonga, Honglu Wu
The loss of bone mass and alteration in bone physiology during space flight are one of the major health risks for astronauts. Although the lack of weight bearing in microgravity is considered a risk factor for bone loss and possible osteoporosis, organisms living in space are also exposed to cosmic radiation and other environmental stress factors. As such, it is still unclear as to whether and by how much radiation exposure contributes to bone loss during space travel, and whether the effects of microgravity and radiation exposure are additive or synergistic...
November 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29149894/comments-on-incidence-of-cancer-among-licensed-commercial-pilots-flying-north-atlantic-routes
#16
EDITORIAL
S M J Mortazavi
Gudmundsdottir et al. in their paper entitled "Incidence of cancer among licensed commercial pilots flying North Atlantic routes" published in Environmental Health have evaluated the effects of exposure to higher levels of cosmic radiation on cancer incidence in the pilots of commercial flights. Despite its remarkable strengths, the paper authored by Gudmundsdottir et al. has some shortcomings. The shortcomings of this paper such as not determining the shape of dose-response relationship for radiation-induced cancers, limitations in flight dose calculations, the weaknesses of CARI-6 as the program used by Gudmundsdottir et al...
November 17, 2017: Environmental Health: a Global Access Science Source
https://www.readbyqxmd.com/read/29136391/effects-of-1-h-16-o-charged-particle-irradiation-on-short-term-memory-and-hippocampal-physiology-in-a-murine-model
#17
Frederico Kiffer, Hannah Carr, Thomas Groves, Julie E Anderson, Tyler Alexander, Jing Wang, John W Seawright, Vijayalakshmi Sridharan, Gwendolyn Carter, Marjan Boerma, Antiño R Allen
Radiation from galactic cosmic rays (GCR) poses a significant health risk for deep-space flight crews. GCR are unique in their extremely high-energy particles. With current spacecraft shielding technology, some of the predominant particles astronauts would be exposed to are (1)H + (16)O. Radiation has been shown to cause cognitive deficits in mice. The hippocampus plays a key role in memory and cognitive tasks; it receives information from the cortex, undergoes dendritic-dependent processing and then relays information back to the cortex...
November 14, 2017: Radiation Research
https://www.readbyqxmd.com/read/29136055/skin-cancer-in-military-pilots-a-special-population-with-special-risk-factors
#18
Bart D Wilkison, Emily B Wong
Military pilots may be at greater risk for skin cancer, particularly melanoma. Military-specific studies are limited, but skin cancer rates in civilian pilots and aircrews have previously been examined. Risk factors for all pilots may include exposure to UV radiation (UVR) at higher altitudes, cosmic radiation, and electromagnetic energy from cockpit instruments, as well as altered sleep-wake cycles. The study of aviation-specific risk factors for skin cancer is relevant to all pilots and dermatologists who care for them...
October 2017: Cutis; Cutaneous Medicine for the Practitioner
https://www.readbyqxmd.com/read/29094687/origin-of-the-heavy-elements-in-binary-neutron-star-mergers-from-a-gravitational-wave-event
#19
Daniel Kasen, Brian Metzger, Jennifer Barnes, Eliot Quataert, Enrico Ramirez-Ruiz
The cosmic origin of elements heavier than iron has long been uncertain. Theoretical modelling shows that the matter that is expelled in the violent merger of two neutron stars can assemble into heavy elements such as gold and platinum in a process known as rapid neutron capture (r-process) nucleosynthesis. The radioactive decay of isotopes of the heavy elements is predicted to power a distinctive thermal glow (a 'kilonova'). The discovery of an electromagnetic counterpart to the gravitational-wave source GW170817 represents the first opportunity to detect and scrutinize a sample of freshly synthesized r-process elements...
November 2, 2017: Nature
https://www.readbyqxmd.com/read/29057337/the-cosmic-microwave-background-radiation-power-spectrum-as-a-random-bit-generator-for-symmetric-and-asymmetric-key-cryptography
#20
Jeffrey S Lee, Gerald B Cleaver
In this note, the Cosmic Microwave Background (CMB) Radiation is shown to be capable of functioning as a Random Bit Generator, and constitutes an effectively infinite supply of truly random one-time pad values of arbitrary length. It is further argued that the CMB power spectrum potentially conforms to the FIPS 140-2 standard. Additionally, its applicability to the generation of a (n × n) random key matrix for a Vernam cipher is established.
October 2017: Heliyon
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