2,233 research outputs found

    Mapping compositional and particle size variations across Silver Lake Playa: Relevance to analyses of Mars TIR data

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    The high spectral and spatial resolution thermal infrared (TIR) data to be acquired from the upcoming Mars Observer-Thermal Emission Spectra (TES) mission will map the composition and texture of the Martian sediments. To prepare for these data, portions of two remote sensing experiments were conducted to test procedures for extracting surface property information from TIR data. Reported here is the continuing analysis of Thermal Infrared Multispectral Scanner (TIMS) data, field emission spectra, laboratory Fourier Transform Infrared (FTIR) reflectance spectra, and field observations with respect to the physical characteristics (composition, emissivity, etc.) of Silver Lake playa in southern California

    Geologic applications of thermal inertia image using HCMM data

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    The author has identified the following significant results. Comparison of a simulated HCMM image of the Pisgah Crater, California test site obtained from aircraft data with an image generated from the preliminary satellite data tape of the area indicates that the HCMM satellite data appears much as predicted by the simulation

    Complexity Measures from Interaction Structures

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    We evaluate new complexity measures on the symbolic dynamics of coupled tent maps and cellular automata. These measures quantify complexity in terms of kk-th order statistical dependencies that cannot be reduced to interactions between k1k-1 units. We demonstrate that these measures are able to identify complex dynamical regimes.Comment: 11 pages, figures improved, minor changes to the tex

    Uniform random colored complexes

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    We present here random distributions on (D+1)(D+1)-edge-colored, bipartite graphs with a fixed number of vertices 2p2p. These graphs are dual to DD-dimensional orientable colored complexes. We investigate the behavior of quantities related to those random graphs, such as their number of connected components or the number of vertices of their dual complexes, as pp \to \infty. The techniques involved in the study of these quantities also yield a Central Limit Theorem for the genus of a uniform map of order pp, as pp \to \infty.Comment: 36 pages, 9 figures, minor additions and correction

    The detection of geothermal areas from Skylab thermal data

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    Skylab-4 X-5 thermal data of the geysers area was analyzed to determine the feasibility of using midday Skylab images to detect geothermal areas. The hottest ground areas indicated on the Skylab image corresponded to south-facing barren or sparsely vegetated slopes. A geothermal area approximately 15 by 30 m coincided with one of the hottest areas indicated by Skylab. This area could not be unambiguously distinguished from the other areas which are believed to be hotter than their surroundings as a result of their topography, and micrometeorological conditions. A simple modification of a previous thermal model was performed and the predicted temperatures for the hottest slopes using representative values was in general agreement with the observed data. It is concluded that data from a single midday Skylab pass cannot be used to locate geothermal areas

    Auto- und Heterotrophic Respiration in the Hohenheim Climate Change Experiment - The Importance of Temperature Change and Vegetation Period

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    Current Climate change (CC) research in soil science mainly focusses on natural ecosystems, without considering the potential of agro-ecosystems for feedback mechanisms to CC and CC mitigation through Carbon(C)-sequestration. We expect that CC induces increasing water limitation under elevated temperature, lowers the intensity of soil respiration and changes the ratio between the amount of root-dependent and basal soil respiration. Such changes might be due to differences in the intrinsic temperature and moisture sensitivity of microbial and root respiration and due to altered root exudation. In this project, we focus on CC-induced effects on plant-dependent and basal soil respiration to improve the estimation of long-term soil organic matter stabilization. Within the Hohenheim Climate Change (HoCC) experiment (established in 2008), barley plants were pulse-labelled with 20-atom% 13CO2 for 4 h using ventilated transparent chambers on warmed and control plots in an agricultural field. The labeling was done during three different stages (advanced tillering, booting and grain-filling) of the vegetation period, at which C-sink strength of shoot and root differs according to plant development. CO2-fluxes and isotopic composition were measured in real time in the field for the first 50h (post labeling) using a 13CO2 isotope analyzer. Results from tracing 13C-fluxes will clarify how soil moisture and long-term elevated temperature affect the overall C-balance in agricultural soils in dependence of the vegetation period. This will allow estimations of direction and strength of feedback mechanisms of terrestrial C-cycling under CC. Overall, insights obtained in this project will provide better understanding of the CC impact on and of temperate agricultural production systems

    Identification of Source Faults of Large Earthquakes in the Turkey‐Syria Border Region Between 1000 CE and the Present, and Their Relevance for the 2023 Mw 7.8 Pazarcık Earthquake

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    The 6 February 2023, Mw 7.8 Pazarcık earthquake in the Turkey-Syria border region raises the question of whether such a large earthquake could have been foreseen, as well as what is the maximum possible magnitude (Mmax) of earthquakes on the East Anatolian Fault (EAF) system and on continental transform faults in general. To answer such questions, knowledge of past earthquakes and of their causative faults is necessary. Here, we integrate data from historical seismology, paleoseismology, archeoseismology, and remote sensing to identify the likely source faults of fourteen Mw ≥ 7 earthquakes between 1000 CE and the present in the region. We find that the 2023 Pazarcık earthquake could have been foreseen in terms of location (the EAF) and timing (an earthquake along this fault was if anything overdue), but not magnitude. We hypothesize that the maximum earthquake magnitude for the EAF is in fact 8.2, that is, a single end-to-end rupture of the entire fault, and that the 2023 Pazarcık earthquake did not reach Mmax by a fortuitous combination of circumstances. We conclude that such unusually large events are hard to model in terms of recurrence intervals, and that seismic hazard assessment along continental transforms cannot be done on individual fault systems but must include neighboring systems as well, because they are not kinematically independent at any time scale

    TDP-43 knockdown impairs neurite outgrowth dependent on its target histone deacetylase 6

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    <p>Abstract</p> <p>Background</p> <p>Trans-activation response element (TAR) DNA binding protein of 43kDa (TDP-43) is causally related to the neurodegenerative diseases frontotemporal dementia and amyotrophic lateral sclerosis being the hallmark protein in the disease-characteristic neuropathological lesions and via genetic linkage. Histone deacetylase 6 (HDAC6) is an established target of the RNA-binding protein TDP-43. HDAC6 is an unusual cytosolic deacetylase enzyme, central for a variety of pivotal cellular functions including aggregating protein turnover, microtubular dynamics and filopodia formation. All these functions are important in the context of neurodegenerative proteinopathies involving TDP-43. We have previously shown in a human embryonic kidney cell line that TDP-43 knockdown significantly impairs the removal of a toxic, aggregating polyQ ataxin-3 fusion protein in an HDAC6-dependent manner. Here we investigated the influence of TDP-43 and its target HDAC6 on neurite outgrowth.</p> <p>Results</p> <p>Human neuroblastoma SH-SY5Y cells with stably silenced TDP-43 showed a significant reduction of neurite outgrowth induced by retinoic acid and brain-derived neurotrophic factor. Re-transfection with TDP-43 as well as HDAC6 rescued retinoic acid-induced neurite outgrowth. In addition, we show that silencing of HDAC6 alone is sufficient to reduce neurite outgrowth of <it>in vitro </it>differentiated SH-SY5Y cells.</p> <p>Conclusions</p> <p>TDP-43 deficiency leads to impairment of neurite growth in an HDAC6-dependent manner, thereby contributing to neurodegenerative events in TDP-43 diseases.</p

    T-duality and Differential K-Theory

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    We give a precise formulation of T-duality for Ramond-Ramond fields. This gives a canonical isomorphism between the "geometrically invariant" subgroups of the twisted differential K-theory of certain principal torus bundles. Our result combines topological T-duality with the Buscher rules found in physics.Comment: 23 pages, typos corrected, submitted to Comm.Math.Phy
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