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https://www.readbyqxmd.com/read/28332561/inertial-bioluminescence-rhythms-at-the-capo-passero-km3net-italia-site-central-mediterranean-sea
#1
J Aguzzi, E Fanelli, T Ciuffardi, A Schirone, J Craig
In the deep sea, the sense of time is dependent on geophysical fluctuations, such as internal tides and atmospheric-related inertial currents, rather than day-night rhythms. Deep-sea neutrino telescopes instrumented with light detecting Photo-Multiplier Tubes (PMT) can be used to describe the synchronization of bioluminescent activity of abyssopelagic organisms with hydrodynamic cycles. PMT readings at 8 different depths (from 3069 to 3349 m) of the NEMO Phase 2 prototype, deployed offshore Capo Passero (Sicily) at the KM3NeT-Italia site, were used to characterize rhythmic bioluminescence patterns in June 2013, in response to water mass movements...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28332519/simultaneous-tracking-of-spin-angle-and-amplitude-beyond-classical-limits
#2
Giorgio Colangelo, Ferran Martin Ciurana, Lorena C Bianchet, Robert J Sewell, Morgan W Mitchell
Measurement of spin precession is central to extreme sensing in physics, geophysics, chemistry, nanotechnology and neuroscience, and underlies magnetic resonance spectroscopy. Because there is no spin-angle operator, any measurement of spin precession is necessarily indirect, for example, it may be inferred from spin projectors at different times. Such projectors do not commute, and so quantum measurement back-action-the random change in a quantum state due to measurement-necessarily enters the spin measurement record, introducing errors and limiting sensitivity...
March 22, 2017: Nature
https://www.readbyqxmd.com/read/28325934/cordillera-zealandia-a-mesozoic-arc-flare-up-on-the-palaeo-pacific-gondwana-margin
#3
L A Milan, N R Daczko, G L Clarke
Two geochemically and temporally distinct components of the Mesozoic Zealandia Cordilleran arc indicate a shift from low to high Sr/Y whole rock ratios at c. 130 Ma. Recent mapping and a reappraisal of published Sr-Nd data combined with new in-situ zircon Hf isotope analyses supports a genetic relationship between the two arc components. A reappraisal of geophysical, geochemical and P-T estimates demonstrates a doubling in thickness of the arc to at least 80 km at c. 130 Ma. Contemporaneously, magmatic addition rates shifted from ~14 km(3)/my per km of arc to a flare-up involving ~100 km(3)/my per km of arc...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28319845/surface-transport-processes-in-charged-porous-media
#4
Jorge Gabitto, Costas Tsouris
Surface transport processes are very important in chemistry, colloidal sciences, engineering, biology, and geophysics. Natural or externally produced charges on surfaces create electrical double layers (EDLs) at the solid-liquid interface. The existence of the EDLs produces several complex processes including bulk and surface transport of ions. In this work, a model is presented to simulate bulk and transport processes in homogeneous porous media comprising big pores. It is based on a theory for capacitive charging by ideally polarizable porous electrodes without Faradaic reactions or specific adsorption of ions...
March 3, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28303951/enhancing-the-sensitivity-of-magnetic-sensors-by-3d-metamaterial-shells
#5
Carles Navau, Rosa Mach-Batlle, Albert Parra, Jordi Prat-Camps, Sergi Laut, Nuria Del-Valle, Alvaro Sanchez
Magnetic sensors are key elements in our interconnected smart society. Their sensitivity becomes essential for many applications in fields such as biomedicine, computer memories, geophysics, or space exploration. Here we present a universal way of increasing the sensitivity of magnetic sensors by surrounding them with a spherical metamaterial shell with specially designed anisotropic magnetic properties. We analytically demonstrate that the magnetic field in the sensing area is enhanced by our metamaterial shell by a known factor that depends on the shell radii ratio...
March 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28303885/major-advance-of-south-georgia-glaciers-during-the-antarctic-cold-reversal-following-extensive-sub-antarctic-glaciation
#6
Alastair G C Graham, Gerhard Kuhn, Ove Meisel, Claus-Dieter Hillenbrand, Dominic A Hodgson, Werner Ehrmann, Lukas Wacker, Paul Wintersteller, Christian Dos Santos Ferreira, Miriam Römer, Duanne White, Gerhard Bohrmann
The history of glaciations on Southern Hemisphere sub-polar islands is unclear. Debate surrounds the extent and timing of the last glacial advance and termination on sub-Antarctic South Georgia in particular. Here, using sea-floor geophysical data and marine sediment cores, we resolve the record of glaciation offshore of South Georgia through the transition from the Last Glacial Maximum to Holocene. We show a sea-bed landform imprint of a shelf-wide last glacial advance and progressive deglaciation. Renewed glacier resurgence in the fjords between c...
March 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28297955/grain-scale-modeling-and-splash-parametrization-for-aeolian-sand-transport
#7
Marc Lämmel, Kamil Dzikowski, Klaus Kroy, Luc Oger, Alexandre Valance
The collision of a spherical grain with a granular bed is commonly parametrized by the splash function, which provides the velocity of the rebounding grain and the velocity distribution and number of ejected grains. Starting from elementary geometric considerations and physical principles, like momentum conservation and energy dissipation in inelastic pair collisions, we derive a rebound parametrization for the collision of a spherical grain with a granular bed. Combined with a recently proposed energy-splitting model [Ho et al...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28297918/energy-partition-scale-by-scale-in-magnetic-archimedes-coriolis-weak-wave-turbulence
#8
A Salhi, F S Baklouti, F Godeferd, T Lehner, C Cambon
Magnetic Archimedes Coriolis (MAC) waves are omnipresent in several geophysical and astrophysical flows such as the solar tachocline. In the present study, we use linear spectral theory (LST) and investigate the energy partition, scale by scale, in MAC weak wave turbulence for a Boussinesq fluid. At the scale k^{-1}, the maximal frequencies of magnetic (Alfvén) waves, gravity (Archimedes) waves, and inertial (Coriolis) waves are, respectively, V_{A}k,N, and f. By using the induction potential scalar, which is a Lagrangian invariant for a diffusionless Boussinesq fluid [Salhi et al...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28293138/effective-equations-governing-an-active-poroelastic-medium
#9
J Collis, D L Brown, M E Hubbard, R D O'Dea
In this work, we consider the spatial homogenization of a coupled transport and fluid-structure interaction model, to the end of deriving a system of effective equations describing the flow, elastic deformation and transport in an active poroelastic medium. The 'active' nature of the material results from a morphoelastic response to a chemical stimulant, in which the growth time scale is strongly separated from other elastic time scales. The resulting effective model is broadly relevant to the study of biological tissue growth, geophysical flows (e...
February 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28273798/investigation-into-the-effect-of-atmospheric-particulate-matter-pm2-5-and-pm10-concentrations-on-gps-signals
#10
Lawrence Lau, Jun He
The Global Positioning System (GPS) has been widely used in navigation, surveying, geophysical and geodynamic studies, machine guidance, etc. High-precision GPS applications such as geodetic surveying need millimeter and centimeter level accuracy. Since GPS signals are affected by atmospheric effects, methods of correcting or eliminating ionospheric and tropospheric bias are needed in GPS data processing. Relative positioning can be used to mitigate the atmospheric effect, but its efficiency depends on the baseline lengths...
March 3, 2017: Sensors
https://www.readbyqxmd.com/read/28272450/standoff-detection-of-uranium-and-its-isotopes-by-femtosecond-filament-laser-ablation-molecular-isotopic-spectrometry
#11
Kyle C Hartig, Isaac Ghebregziabher, Igor Jovanovic
The ability to perform not only elementally but also isotopically sensitive detection and analysis at standoff distances is impor-tant for remote sensing applications in diverse ares, such as nuclear nonproliferation, environmental monitoring, geophysics, and planetary science. We demonstrate isotopically sensitive real-time standoff detection of uranium by the use of femtosecond filament-induced laser ablation molecular isotopic spectrometry. A uranium oxide molecular emission isotope shift of 0.05 ± 0...
March 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28254939/experimental-constraints-on-the-damp-peridotite-solidus-and-oceanic-mantle-potential-temperature
#12
Emily Sarafian, Glenn A Gaetani, Erik H Hauri, Adam R Sarafian
Decompression of hot mantle rock upwelling beneath oceanic spreading centers causes it to exceed the melting point (solidus), producing magmas that ascend to form basaltic crust ~6 to 7 kilometers thick. The oceanic upper mantle contains ~50 to 200 micrograms per gram of water (H2O) dissolved in nominally anhydrous minerals, which-relative to its low concentration-has a disproportionate effect on the solidus that has not been quantified experimentally. Here, we present results from an experimental determination of the peridotite solidus containing known amounts of dissolved hydrogen...
March 3, 2017: Science
https://www.readbyqxmd.com/read/28253692/the-influence-of-temporally-varying-noise-from-seismic-air-guns-on-the-detection-of-underwater-sounds-by-seals
#13
Jillian M Sills, Brandon L Southall, Colleen Reichmuth
Standard audiometric data are often applied to predict how noise influences hearing. With regard to auditory masking, critical ratios-obtained using tonal signals and flat-spectrum maskers-can be combined with noise spectral density levels derived from 1/3-octave band levels to predict signal amplitudes required for detection. However, the efficacy of this conventional model of masking may vary based on features of the signal and noise in question. The ability of resource managers to quantify masking from intermittent seismic noise is relevant due to widespread geophysical exploration...
February 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28239224/ice-sheet-dynamics-through-the-quaternary-on-the-mid-norwegian-continental-margin-inferred-from-3d-seismic-data
#14
A Montelli, J A Dowdeswell, D Ottesen, S E Johansen
Reconstructing the evolution of ice sheets is critical to our understanding of the global environmental system, but most detailed palaeo-glaciological reconstructions have hitherto focused on the very recent history of ice sheets. Here, we present a three-dimensional (3D) reconstruction of the changing nature of ice-sheet derived sedimentary architecture through the Quaternary Ice Age of almost 3 Ma. An extensive geophysical record documents a marine-terminating, calving Fennoscandian Ice Sheet (FIS) margin present periodically on the mid-Norwegian shelf since the beginning of the Quaternary...
February 2017: Marine and Petroleum Geology
https://www.readbyqxmd.com/read/28229109/interaction-between-circadian-rhythms-and-stress
#15
REVIEW
C E Koch, B Leinweber, B C Drengberg, C Blaum, H Oster
Life on earth has adapted to the day-night cycle by evolution of internal, so-called circadian clocks that adjust behavior and physiology to the recurring changes in environmental conditions. In mammals, a master pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus receives environmental light information and synchronizes peripheral tissues and central non-SCN clocks to geophysical time. Regulatory systems such as the hypothalamus-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS), both being important for the regulation of stress responses, receive strong circadian input...
February 2017: Neurobiology of Stress
https://www.readbyqxmd.com/read/28218270/magma-plumbing-system-and-seismicity-of-an-active-mid-ocean-ridge-volcano
#16
Florian Schmid, Vera Schlindwein, Ivan Koulakov, Aline Plötz, John-Robert Scholz
At mid-ocean ridges volcanism generally decreases with spreading rate but surprisingly massive volcanic centres occur at the slowest spreading ridges. These volcanoes can host unexpectedly strong earthquakes and vigorous, explosive submarine eruptions. Our understanding of the geodynamic processes forming these volcanic centres is still incomplete due to a lack of geophysical data and the difficulty to capture their rare phases of magmatic activity. We present a local earthquake tomographic image of the magma plumbing system beneath the Segment 8 volcano at the ultraslow-spreading Southwest Indian Ridge...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28190902/constraining-the-kinematics-of-metropolitan-los-angeles-faults-with-a-slip-partitioning-model
#17
S Daout, S Barbot, G Peltzer, M-P Doin, Z Liu, R Jolivet
Due to the limited resolution at depth of geodetic and other geophysical data, the geometry and the loading rate of the ramp-décollement faults below the metropolitan Los Angeles are poorly understood. Here we complement these data by assuming conservation of motion across the Big Bend of the San Andreas Fault. Using a Bayesian approach, we constrain the geometry of the ramp-décollement system from the Mojave block to Los Angeles and propose a partitioning of the convergence with 25.5 ± 0.5 mm/yr and 3...
November 16, 2016: Geophysical Research Letters
https://www.readbyqxmd.com/read/28180925/innovative-approaches-to-collaborative-groundwater-governance-in-the-united-states-case-studies-from-three-high-growth-regions-in-the-sun-belt
#18
Sharon B Megdal, Andrea K Gerlak, Ling-Yee Huang, Nathaniel Delano, Robert G Varady, Jacob D Petersen-Perlman
Groundwater is an increasingly important source of freshwater, especially where surface water resources are fully or over-allocated or becoming less reliable due to climate change. Groundwater reliance has created new challenges for sustainable management. This article examines how regional groundwater users coordinate and collaborate to manage shared groundwater resources, including attention to what drives collaboration. To identify and illustrate these facets, this article examines three geographically diverse cases of groundwater governance and management from the United States Sun Belt: Orange County Water District in southern California; Prescott Active Management Area in north-central Arizona; and the Central Florida Water Initiative in central Florida...
February 8, 2017: Environmental Management
https://www.readbyqxmd.com/read/28133779/factors-affecting-the-united-nations-response-to-natural-disasters-what-determines-the-allocation-of-the-central-emergency-response-fund
#19
Tyler D Robinson, Thiago M Oliveira, Stephanie Kayden
Natural disasters can overwhelm the domestic response of a country, leaving it dependent on external humanitarian relief. The Central Emergency Response Fund (CERF) of the United Nations centralises humanitarian funding and thus allows for a rapid response. This study combined data to analyse the factors that affected the allocation of CERF funding to countries that suffered a natural disaster between 2007 and 2013. It generated descriptive statistics and information on relative risks, and performed regressions of CERF funding across countries...
January 30, 2017: Disasters
https://www.readbyqxmd.com/read/28129150/the-spurs-algorithm-for-resampling-an-irregularly-sampled-signal-onto-a-cartesian-grid
#20
Amir Kiperwas, Daniel Rosenfeld, Yonina C Eldar
We present an algorithm for resampling a function from its values on a non-Cartesian grid onto a Cartesian grid. This problem arises in many applications such as MRI, CT, radio astronomy and geophysics. Our algorithm, termed SParse Uniform ReSampling (SPURS), employs methods from modern sampling theory to achieve a small approximation error while maintaining low computational cost. The given non-Cartesian samples are projected onto a selected intermediate subspace, spanned by integer translations of a compactly supported kernel function...
November 1, 2016: IEEE Transactions on Medical Imaging
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