163 research outputs found

    Damping of Coherent Transverse Oscillations in PETRA

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    A highly contiguous genome assembly of the bat hawkmoth Hyles vespertilio (Lepidoptera: Sphingidae)

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    Adapted to different ecological niches, moth species belonging to the Hyles genus exhibit a spectacular diversity of larval color patterns. These species diverged ∼7.5 million years ago, making this rather young genus an interesting system to study a wide range of questions including the process of speciation, ecological adaptation, and adaptive radiation

    Linking satellite derived LAI patterns with subsoil heterogeneity using large-scale ground-based electromagnetic induction measurements

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    Patterns in crop development and yield are often directly related to lateral and vertical changes in soil texture causing changes in available water and resource supply for plant growth, especially under dry conditions. Relict geomorphologic features, such as old river channels covered by shallow sediments can challenge assumptions of uniformity in precision agriculture, subsurface hydrology, and crop modeling. Hence a better detection of these subsurface structures is of great interest. In this study, the origins of narrow and undulating leaf area index (LAI) patterns showing better crop performance in large scale multi-temporal satellite imagery were for the first time interpreted by proximal soil sensor data. A multi-receiver electromagnetic induction (EMI) sensor measuring soil apparent electrical conductivity (ECa) for six depths of exploration (DOE) ranging from 0–0.25 to 0–1.9 m was used as reconnaissance soil survey tool in combination with selected electrical resistivity tomography (ERT) transects, and ground truth texture data to investigate lateral and vertical changes of soil properties at ten arable fields. The moderate to excellent spatial consistency (R2 0.19–0.82) of ECa patterns and LAI crop marks that indicate a higher water storage capacity as well as the increased correlations between large-offset ECa data and the subsoil clay content and soil profile depth, implies that along this buried paleo-river structure the subsoil is mainly responsible for better crop development in drought periods. Furthermore, observed stagnant water in the subsoil indicates that this paleo-river structure still plays an important role in subsurface hydrology. These insights should be considered and implemented in local hydrological as well as crop models

    Lattice Boltzmann simulations of lamellar and droplet phases

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    Lattice Boltzmann simulations are used to investigate spinodal decomposition in a two-dimensional binary fluid with equilibrium lamellar and droplet phases. We emphasise the importance of hydrodynamic flow to the phase separation kinetics. For mixtures slightly asymmetric in composition the fluid phase separates into bulk and lamellar phases with the lamellae forming distinctive spiral structures to minimise their elastic energy.Comment: 19 pages, 5 figure

    Revisiting the transits of CoRoT-7b at a lower activity level

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    CoRoT-7b, the first super-Earth with measured radius discovered, has opened the new field of rocky exoplanets characterisation. To better understand this interesting system, new observations were taken with the CoRoT satellite. During this run 90 new transits were obtained in the imagette mode. These were analysed together with the previous 151 transits obtained in the discovery run and HARPS radial velocity observations to derive accurate system parameters. A difference is found in the posterior probability distribution of the transit parameters between the previous CoRoT run (LRa01) and the new run (LRa06). We propose this is due to an extra noise component in the previous CoRoT run suspected to be transit spot occultation events. These lead to the mean transit shape becoming V-shaped. We show that the extra noise component is dominant at low stellar flux levels and reject these transits in the final analysis. We obtained a planetary radius, Rp=1.585±0.064RR_p= 1.585\pm0.064\,R_{\oplus}, in agreement with previous estimates. Combining the planetary radius with the new mass estimates results in a planetary density of 1.19±0.27ρ 1.19 \pm 0.27\, \rho_{\oplus} which is consistent with a rocky composition. The CoRoT-7 system remains an excellent test bed for the effects of activity in the derivation of planetary parameters in the shallow transit regime.Comment: 13 pages, 13 figures, accepted to A&

    Polarimetric Properties of Flux-Ropes and Sheared Arcades in Coronal Prominence Cavities

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    The coronal magnetic field is the primary driver of solar dynamic events. Linear and circular polarization signals of certain infrared coronal emission lines contain information about the magnetic field, and to access this information, either a forward or an inversion method must be used. We study three coronal magnetic configurations that are applicable to polar-crown filament cavities by doing forward calculations to produce synthetic polarization data. We analyze these forward data to determine the distinguishing characteristics of each model. We conclude that it is possible to distinguish between cylindrical flux ropes, spheromak flux ropes, and sheared arcades using coronal polarization measurements. If one of these models is found to be consistent with observational measurements, it will mean positive identification of the magnetic morphology that surrounds certain quiescent filaments, which will lead to a greater understanding of how they form and why they erupt.Comment: 22 pages, 8 figures, Solar Physics topical issue: Coronal Magnetis

    The future of planetary atmospheric, surface, and interior science using radio and laser links

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    Studies of planetary systems using spacecraft radio links constitute the field of Radio Science (RS). Experiments have been conducted on almost every planetary mission in the past five decades and have led to numerous discoveries. With substantial technical advancements in recent years, the following significant accomplishments are noted: • Elucidated the thermal history of the Moon from the GRAIL high precision gravitational field • Unveiled the interiors of Titan, Enceladus, Mercury, Phobos, Vesta, Ceres, and cometary nuclei from gravity fields, contributing to understanding their origins (Figure 1) • Sounded Titan, Saturn, and Pluto's atmospheres • Explored the surface properties of Pluto and 67P/Churyumov-Gerasimenko • Refined models for the atmospheres, surfaces, and interior structure of Mars and Venus • Juno and Cassini are currently measuring the gravity fields of Jupiter and Saturn to reveal their interior structures • Provided evidence for subsurface oceans on icy moons to expand understanding of potentially habitable bodies • Investigated the solar corona and the interaction of the solar wind with planetary atmospheres, and • Profiled the structure of Saturn's rings, which interact with moonlets

    A Helicity-Based Method to Infer the CME Magnetic Field Magnitude in Sun and Geospace: Generalization and Extension to Sun-Like and M-Dwarf Stars and Implications for Exoplanet Habitability

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    Patsourakos et al. (Astrophys. J. 817, 14, 2016) and Patsourakos and Georgoulis (Astron. Astrophys. 595, A121, 2016) introduced a method to infer the axial magnetic field in flux-rope coronal mass ejections (CMEs) in the solar corona and farther away in the interplanetary medium. The method, based on the conservation principle of magnetic helicity, uses the relative magnetic helicity of the solar source region as input estimates, along with the radius and length of the corresponding CME flux rope. The method was initially applied to cylindrical force-free flux ropes, with encouraging results. We hereby extend our framework along two distinct lines. First, we generalize our formalism to several possible flux-rope configurations (linear and nonlinear force-free, non-force-free, spheromak, and torus) to investigate the dependence of the resulting CME axial magnetic field on input parameters and the employed flux-rope configuration. Second, we generalize our framework to both Sun-like and active M-dwarf stars hosting superflares. In a qualitative sense, we find that Earth may not experience severe atmosphere-eroding magnetospheric compression even for eruptive solar superflares with energies ~ 10^4 times higher than those of the largest Geostationary Operational Environmental Satellite (GOES) X-class flares currently observed. In addition, the two recently discovered exoplanets with the highest Earth-similarity index, Kepler 438b and Proxima b, seem to lie in the prohibitive zone of atmospheric erosion due to interplanetary CMEs (ICMEs), except when they possess planetary magnetic fields that are much higher than that of Earth.Comment: http://adsabs.harvard.edu/abs/2017SoPh..292...89

    Maladaptive behaviors are linked with inefficient sleep in individuals with developmental disabilities

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    The purpose of the current study was to assess the relations between nightly sleep patterns and the frequency of daily maladaptive behavior. Antecedent and consequential relations between sleep patterns and behavior were evaluated with time series analysis. Sleep efficiency and maladaptive behavior were determined for 20 female residents of an institutional care facility for adults with developmental disabilities. Daily maladaptive behavioral data and nightly sleep/awake logs were collected for 4 months for each participant. Efficient sleep patterns were significantly associated with lower frequencies of maladaptive behaviors. All lagged cross-correlations 8 days before and 8 days after an evening of sleep were significant. These findings suggested that inefficient sleep was associated with increased maladaptive behaviors and that the lagged associations reflected a chronic but not an acute linkage between sleep and behavior
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