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Short Range (short + range)
Terms modified by Short Range Selected AbstractsA diffusible signal attracts olfactory sensory axons toward their target in the developing brain of the mothDEVELOPMENTAL NEUROBIOLOGY, Issue 1 2003Lynne A. Oland Abstract The signals that olfactory receptor axons use to navigate to their target in the CNS are still not well understood. In the moth Manduca sexta, the primary olfactory pathway develops postembryonically, and the receptor axons navigate from an experimentally accessible sensory epithelium to the brain along a pathway long enough for detailed study of regions in which axon behavior changes. The current experiments ask whether diffusible factors contribute to receptor axon guidance. Explants were made from the antennal receptor epithelium and co-cultured in a collagen gel matrix with slices of various regions of the brain. Receptor axons were attracted toward the central regions of the brain, including the protocerebrum and antennal lobe. Receptor axons growing into a slice of the most proximal region of the antennal nerve, where axon sorting normally occurs, showed no directional preference. When the antennal lobe was included in the slice, the receptor axons entering the sorting region grew directly toward the antennal lobe. Taken together with the previous in vivo experiments, the current results suggest that an attractive diffusible factor can serve as one cue to direct misrouted olfactory receptor axons toward the medial regions of the brain, where local cues guide them to the antennal lobe. They also suggest that under normal circumstances, in which the receptor axons follow a pre-existing pupal nerve to the antennal lobe, the diffusible factor emanating from the lobe acts in parallel and at short range to maintain the fidelity of the path into the antennal lobe. © 2003 Wiley Periodicals, Inc. J Neurobiol 56: 24,40, 2003 [source] The influence of parent material on topsoil geochemistry in eastern EnglandEARTH SURFACE PROCESSES AND LANDFORMS, Issue 13 2003B. G. Rawlins Abstract The topsoil of around 10 000 km2 in eastern England has recently been sampled intensely at 4609 sites to characterize its geochemistry. The parent materials, which include both solid geology and Quaternary sediments, range in age from Permian to Holocene. The distributions of the concentrations of major and trace elements have been characterized geostatistically, and the role of parent material on their spatial structure (anisotropy) and their spatial relationships (coregionalization) have been investigated. Analysis of variance with the sites grouped by major parent material type showed that this classi,cation accounted for 14 to 48 per cent of the variance for the various elements. Global variograms of 13 elements (Al, As, Ca, Cr, Cu, Fe, Mg, Mo, Ni, P, Pb, Ti, and U) have been computed and modelled. Eleven of the variograms seem to comprise two structures, both of which we modelled with spherical functions, one of short range, 3·5 to 9 km, and the other with a range of 15 to 23 km. The models included a nugget variance, which varied from 27 per cent (for As, Fe, and Mg) to 63 per cent (for P) of the total. The long-range structures are related to the separations of the major parent materials. The variograms of several elements showed appreciable anisotropy, most notably that of Mg. Anisotropy is evident at short ranges of less than 5 km. This accords with the geological structure of the beds which dip from west to east so that their outcrops are elongated from north to south. A linear model of coregionalization ,tted to the data emphasized several important geochemical associations, which we interpret. Elements commonly associated with clay minerals (Mg, Al) and the clay size fraction (Ti) are dominated by the long-range structure of the coregionalization, whilst several trace elements (As, Cr, Ni and U) are spatially correlated with Fe over short distances, through adsorption of the former on the surfaces of Fe oxyhydroxides. The topsoil around large urban areas is enriched in lead, but it is not clear whether anthropogenic sources are responsible for this metal's anomalous spatial relationships with other elements. Crown copyright © 2003. Reproduced with the permission of Her Majesty's Stationery Of,ce. Published by John Wiley & Sons, Ltd. [source] Physical and chemical cues influencing the oviposition behaviour of Aphidius erviENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2000Donatella Battaglia Abstract The oviposition behaviour of the aphid parasitoid Aphidius ervi Haliday is influenced by both chemical and physical cues. Oviposition attack responses were elicited by paint pigments sealed into the tip of a glass capillary tube. Parasitoids reacted to yellow pigments with repeated oviposition attack responses, but they did not react to green pigments. The spectrum of reflected light from the yellow pigments was very similar to that from the ,green' natural host Acyrthosiphon pisum (Harris), with a high proportion of the total radiation energy being emitted in the yellow-orange wavebands (580,660 nm). Pea aphid cornicle secretion also elicited oviposition attack responses, which were not exclusively induced by its pale yellow-green colour. In fact, the oviposition attack response to capillary tips coated with cornicle secretion remained evident under red light conditions, which, in contrast, nearly completely suppressed the response to yellow pigments. Chemical compounds from cornicle secretion do not appear to be involved in parasitoid orientation, even though they stimulate intense oviposition attack responses. Olfactometer experiments showed that the putative kairomone involved acts only at very short range or on contact. Host exuviae, which also elicited strong and persistent oviposition reactions from A. ervi females, appear to be a good alternative source of ovipositional kairomone(s). This work confirms the existence of an aphid cuticular kairomone. [source] Sensory Systems and Spatial Memory in the Fruit Bat Rousettus aegyptiacusETHOLOGY, Issue 8 2005Richard A. Holland The megachiropteran fruit bat Rousettus aegyptiacus is able to orient and navigate using both vision and echolocation. These two sensory systems have different environmental constraints however, echolocation being relatively short range when compared with vision. Despite this difference, an experiment testing their memory of a perch location demonstrates that once the location of a perch is learned R. aegyptiacus is not influenced by the movement of local landmark cues in the vicinity of the perch under either light or dark conditions. Thus despite the differing constraints of vision and echolocation, this suggests a place is remembered as a location in space and not by associations with landmarks in the vicinity. A decrease in initial performance when the task was repeated in the dark suggested the possibility that a memory of a location learned using vision does not generalize to echolocation. [source] Polysaccharide-Derived Carbons for Polar Analyte SeparationsADVANCED FUNCTIONAL MATERIALS, Issue 11 2010Robin J. White Abstract Highly mesoporous (Brunauer,Emmett,Teller surface area, SBET,>,200,m2,g,1; mesopore volume,>,1,cm3,g,1) carbonaceous materials are prepared in a truly sustainable manner, from the naturally occurring polysaccharide alginic acid. This approach yields large mesoporous materials (pore diameter,>,14,nm) significantly without the use of a template or carbonization catalyst. The direct thermal decomposition of mesoporous forms of the acidic polysaccharide allows for an extremely flexible material preparation strategy. Materials can be prepared at any desired carbonization temperature (e.g., 200,1000,°C), possessing similar textural properties, but progressively presenting more uniform surface functionality through this temperature range, from more oxygenated surfaces at low temperatures to increasingly aromatic/graphitic-like surfaces. The high-temperature material (i.e., 1000,°C), while predominantly amorphous, presents some short range (turbostratic) ordering, providing sufficiently polarizable surfaces on which to perform challenging liquid phase separations of polar sugar analytes. [source] Effect of vegetation management on autumn dispersal of Tetranychus urticae (Acari: Tetranychidae) from tomatoJOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2009E. D. Meck Abstract Autumn dispersal of twospotted spider mite (Tetranychus urticae Koch) from tomato to overwintering host plants was studied in field experiments during 2004,2006. Three vegetation management strategies (herbicide, cultivation and no vegetation control) were established around mite-infested, senescing tomato plants. Tetranychus urticae dispersal was monitored using trap plants of common chickweed (Stellaria media) at 2, 6 and 12 m from the tomatoes within each vegetation management plot. Chickweed plants were sampled in the autumn and spring from 2004 to 2006. Sticky traps were placed next to trap plants in the autumn of 2005 to monitor aerial dispersal of mites. Mite populations infesting chickweed were low, and autumn dispersal of mites from tomatoes to the chickweed plots was considered to be short range. The vegetation management strategies had no effect on mite densities found in the chickweed, but the capture of mites on sticky traps indicated that aerial dispersal was also a means of dispersal to overwintering hosts. [source] New Traversability Indices and Traversability Grid for Integrated Sensor/Map-Based NavigationJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2003Homayoun Seraji This paper presents new measures of terrain traversability at short range and long range of a mobile robot; namely, local and global traversability indices. The sensor-based local traversability index is related by a set of linguistic rules to large obstacles and surface softness within a short range of the robot measured by on-board sensors. The map-based global traversability index is obtained from the terrain topographic map, and is based on major surface features such as hills and lakes within a long range of the robot. These traversability indices complement the mid-range sensor-based regional traversability index introduced earlier. Each traversability index is represented by four fuzzy sets with the linguistic labels {POOR, LOW, MODERATE, HIGH}, corresponding to surfaces that are unsafe, moderately-unsafe, moderately-safe, and safe for traversal, respectively. The global terrain analysis also leads to the new concepts of traversability map and traversability grid for representation of terrain quality based on the global map information. The traversability indices are used in two sensor-based traverse-local and traverse-regional behaviors and one map-based traverse-global behavior. These behaviors are integrated with a map-based seek-goal behavior to ensure that the mobile robot reaches its goal safely while avoiding both sensed and mapped terrain hazards. This provides a unified system in which the two independent sources of terrain quality information, i.e., prior maps and on-board sensors, are integrated together for reactive robot navigation. The paper is concluded by a graphical simulation study. © 2003 Wiley Periodicals, Inc. [source] Beam-size effects in radiation damage in insulin and thaumatin crystalsJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2005A. Wagner Cryocooled insulin and thaumatin crystals were irradiated in a series of alternating data collections and high-dose-rate exposures using either a vertically focused or vertically defocused beam. The main result is that the radiation damage is limited to the exposed region, which can be explained by the short range of the photoelectrons and the Auger electron cascade produced by light elements. Consequently, the unexposed angular range provides significantly improved data quality and electron density compared with previously exposed angular wedges of the crystal when a vertically focused beam is used, while no differences are observed between a fresh wedge and an exposed region for the vertically defocused beam. On the other hand, the focused beam provides higher I/,I ratios at high resolution than homogeneous sample illumination but also causes more rapid sample deterioration. [source] FHSS optical wireless transceiver for short range low-speed indoor sensor interconnectionMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2006F. Delgado Abstract Experimental and simulation results from the operation of a prototype of wireless indoor optical transceiver based on frequency hopping techniques are presented. We choose spread spectrum techniques, as it allows multiple simultaneous accesses and also increases the robustness of the system against multipath-induced distortion. It also reduces the effect of narrowband interference, as could be low-frequency optical noise from fluorescence or incandescence lamps. FHSS techniques also allow coexistence with IrDA or remote control emitting devices without causing of suffering interferences. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2193,2197, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21889 [source] Xanthomonas axonopodis pv. citri: factors affecting successful eradication of citrus cankerMOLECULAR PLANT PATHOLOGY, Issue 1 2004James H. Graham SUMMARY Taxonomic status:, Bacteria, Proteobacteria, gamma subdivision, Xanthomodales, Xanthomonas group, axonopodis DNA homology group, X. axonopodis pv. citri (Hasse) Vauterin et al. Microbiological properties:, Gram negative, slender, rod-shaped, aerobic, motile by a single polar flagellum, produces slow growing, non-mucoid colonies in culture, ecologically obligate plant parasite. Host range:, Causal agent of Asiatic citrus canker on most Citrus spp. and close relatives of Citrus in the family Rutaceae. Disease symptoms:, Distinctively raised, necrotic lesions on fruits, stems and leaves. Epidemiology:, Bacteria exude from lesions during wet weather and are disseminated by splash dispersal at short range, windblown rain at medium to long range and human assisted movement at all ranges. Crop loss:, Severe infections cause defoliation, blemished fruit, premature fruit drop, die-back of twigs and general debilitation of the tree. Distribution:, Citrus canker is not present in all subtropical to tropical regions of citriculture in the world, so considerable regulatory efforts are expended to prevent the introduction and spread of X. axonopodis pv. citri into areas in the Americas, Australia and elsewhere, with climates conducive to the disease. Importance:, Limited strategies exist for suppression of citrus canker on more susceptible cultivars. Blemished fruit are unmarketable and exposed fruit are restricted in market access. The economic impact of loss of markets is much greater than that from yield and quality reductions of the crop. Useful websites:,http://doacs.state.fl.us/canker , http://www.apsnet.org/education/lessonsplantpath/citruscanker/top.htm , http://www.apsnet.org/online/feature/citruscanker/ , http://www.plantmanagementnetwork.org/pub/php/review/citruscanker/ , http://www.abecitrus.com.br/fundecitrus.html , http://www.biotech.ufl.edu/PlantContainment/canker.htm , http://www.aphis.usda.gov/oa/ccanker/ . [source] Water Barrier Ship Self Defense LethalityNAVAL ENGINEERS JOURNAL, Issue 4 2000Charles E. Higdon ABSTRACT The Naval Surface Warfare Center Dahlgren Division has investigated technology for the Office of Naval Research (ONR) that has the potential to be very effective in defending Navy platforms against high-speed, sea-skimming anti-ship cruise missiles (ASCMs). This technology uses a new kill mechanism, a wall of water, to provide a low cost, universal terminal defense system for Navy ships. The Water Barrier or wall of water is generated from the shallow detonation of multiple underwater explosive charges to protect the ship from attacking sea skimmers. This terminal defense concept can be employed to slow or stop debris and warhead fragments from missiles killed at short range to preclude significant damage to own ship. Furthermore, the Water Barrier would defeat the fuzing and structure of ASCMs that have penetrated the inner self-defense layer. This paper describes the Water Barrier Concept that provides terminal defense for Navy ships, the formation of the wall of water that defeats sea skimming ASCMs, and the field tests that demonstrate the viability of the concept. Finally, this paper documents the 1997 field test results that demonstrate the lethality of the Water Barrier against tactical battlefield missile warheads and structures. [source] Mixed singlet-triplet superconducting state in doped antiferromagnetsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2006A. Maci¸ag Abstract We analyze symmetry mixing in the superconducting (SC) order parameter of planar cuprates. The behavior of thermal conductivity observed in some systems doped with magnetic impurities or in some systems exposed to external magnetic field seems to indicate that such symmetry mixing takes place. We discuss this phenomenon in the framework of the spin polaron model (SPM). We assume that antiferromagnetic (AF) correlations, which are at least of short range, tend to confine motion of holes which have been created in the AF spin background. The nature of the propagation of quasiparticles which are hole-like and the nature of the interaction between quasiparticles is determined by a tendency to restore the local AF order. It is known that two holes in the t ,J model (tJ M) form bound states with dx 2,y2 or p-wave symmetry. The d-wave bound state has lower energy and is the ground state. The mixing of d-wave symmetry with p-wave symmetry takes place in the SC order parameter at some range of finite values of the doping parameter. That range lies at the applicability verge of the SPM, where AF correlation are already very short. On the other hand, these correlations may be strengthened by above mentioned external factors, which seems to explain why symmetry mixing is observed in this case. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The Chinese interbank repo market: An analysis of term premiumsTHE JOURNAL OF FUTURES MARKETS, Issue 2 2006Longzhen Fan Because of the lack of short-term government bonds, the interbank repo market in China has been providing the best information about market-driven short-term interest rates since its inception. This article examines the behavior of the repo rates of various terms and their term premiums. The work in this article supplements the study by F. Longstaff (2000), which reports supportive evidence for the pure expectations hypothesis over the short range of the term structure with the use of repo data from the United States. It is found that the pure expectations hypothesis is statistically rejected, although the term premiums are economically small. It is shown that the short-term repo rate, repo rate volatility, repo market liquidity, and repo rate spreads are all important in determining the term premiums. © 2006 Wiley Periodicals, Inc. Jrl Fut Mark 26:153,167, 2006 [source] Scale-dependent verification of ensemble forecastsTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 633 2008Thomas Jung Abstract A scale-dependent verification of the ECMWF ensemble prediction system (EPS) in the Northern Hemisphere is presented. The relationship between spread and skill is investigated alongside probabilistic forecast skill for planetary, synoptic and subsynoptic spectral bands. Since the ECMWF model is a spectral model, the three spectral bands have been isolated using total and zonal wavenumber filters. Diagnosed overdispersiveness of ECMWF EPS in the short range is primarily due to excessive amounts of spread on synoptic scales. Diagnosed underdispersiveness of the ensemble beyond day 5 of the forecast can be explained by too little spread on both synoptic and planetary scales. Copyright © 2008 Royal Meteorological Society [source] The ECMWF operational implementation of four-dimensional variational assimilation.THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 564 2000I: Experimental results with simplified physics Abstract This paper presents results of a comparison between four-dimensional variational assimilation (4D-Var). using a 6-hour assimilation window and simplified physics during the minimization, and three-dimensional variational assimilation (3D-Var). Results have been obtained at ,operational' resolution T213L31/T63L31. (T defines the spectral triangular truncation and L the number of levels in the vertical, with the first parameters defining the resolution of the model trajectory, and the second the resolution of the inner-loop.) The sensitivity of the 4D-Var performance to different set-ups is investigated. In particular, the performance of 4D-Var in the Tropics revealed some sensitivity to the way the adiabatic nonlinear normal-mode initialization of the increments was performed. Going from four outer-loops to only one (as in 3D-Var), together with a change to the 1997 formulation of the background constraint and an initialization of only the small scales, helped to improve the 4D-Var performance. Tropical scores then became only marginally worse for 4D-Var than for 3D-Var. Twelve weeks of experimentation with the one outer-loop 4D-Var and the 1997 background formulation have been studied. The averaged scores show a small but consistent improvement in both hemispheres at all ranges. In the short range, each two- to three-week period has been found to be slightly positive throughout the troposphere. The better short-range performance of the 4D-Var system is also shown by the fits of the background fields to the data. More results are presented for the Atlantic Ocean area during FASTEX (the Fronts and Atlantic Storm-Track Experiment), during which 4D-Var is found to perform better. In individual synoptic cases corresponding to interesting Intensive Observing Periods, 4D-Var has a clear advantage over 3D-Var during rapid cyclogeneses. The very short-range forecasts used as backgrounds are much closer to the data over the Atlantic for 4D-Var than for 3D-Var. The 4D-Var analyses also display more day-to-day variability. Some structure functions are illustrated in the 4D-Var case for a height observation inserted at the beginning, in the middle or at the end of the assimilation window. The dynamical processes seem to be relevant, even with a short 6-hour assimilation period, which explains the better overall performance of the 4D-Var system. [source] Summary of recommendations of the first workshop on Postprocessing and Downscaling Atmospheric Forecasts for Hydrologic Applications held at Météo-France, Toulouse, France, 15,18 June 2009ATMOSPHERIC SCIENCE LETTERS, Issue 2 2010John Schaake Abstract Hydrologists are increasingly using numerical weather forecasting products as an input to their hydrological models. These products are often generated on relatively coarse scales compared with hydrologically relevant basin units and suffer systematic biases that may have considerable impact when passed through the nonlinear hydrological filters. Therefore, the data need processing before they can be used in hydrological applications. This manuscript summarises discussions and recommendations of the first workshop on Postprocessing and Downscaling Atmospheric Forecasts for Hydrologic Applications held at Meteo France, Toulouse, France, 15,18 June 2008. The recommendations were developed by work groups that considered the following three areas of ensemble prediction: (1) short range (0,2 days), (2) medium range (3 days to 2 weeks), and (3) sub-seasonal and seasonal (beyond 2 weeks). Copyright © 2010 Royal Meteorological Society [source] The influence of parent material on topsoil geochemistry in eastern EnglandEARTH SURFACE PROCESSES AND LANDFORMS, Issue 13 2003B. G. Rawlins Abstract The topsoil of around 10 000 km2 in eastern England has recently been sampled intensely at 4609 sites to characterize its geochemistry. The parent materials, which include both solid geology and Quaternary sediments, range in age from Permian to Holocene. The distributions of the concentrations of major and trace elements have been characterized geostatistically, and the role of parent material on their spatial structure (anisotropy) and their spatial relationships (coregionalization) have been investigated. Analysis of variance with the sites grouped by major parent material type showed that this classi,cation accounted for 14 to 48 per cent of the variance for the various elements. Global variograms of 13 elements (Al, As, Ca, Cr, Cu, Fe, Mg, Mo, Ni, P, Pb, Ti, and U) have been computed and modelled. Eleven of the variograms seem to comprise two structures, both of which we modelled with spherical functions, one of short range, 3·5 to 9 km, and the other with a range of 15 to 23 km. The models included a nugget variance, which varied from 27 per cent (for As, Fe, and Mg) to 63 per cent (for P) of the total. The long-range structures are related to the separations of the major parent materials. The variograms of several elements showed appreciable anisotropy, most notably that of Mg. Anisotropy is evident at short ranges of less than 5 km. This accords with the geological structure of the beds which dip from west to east so that their outcrops are elongated from north to south. A linear model of coregionalization ,tted to the data emphasized several important geochemical associations, which we interpret. Elements commonly associated with clay minerals (Mg, Al) and the clay size fraction (Ti) are dominated by the long-range structure of the coregionalization, whilst several trace elements (As, Cr, Ni and U) are spatially correlated with Fe over short distances, through adsorption of the former on the surfaces of Fe oxyhydroxides. The topsoil around large urban areas is enriched in lead, but it is not clear whether anthropogenic sources are responsible for this metal's anomalous spatial relationships with other elements. Crown copyright © 2003. Reproduced with the permission of Her Majesty's Stationery Of,ce. Published by John Wiley & Sons, Ltd. [source] A Note on the Spatial Correlation Structure of County-Level Growth in the U.S.JOURNAL OF REGIONAL SCIENCE, Issue 3 2001Christopher H. Wheeler This paper examines the spatial correlation structure of county-level growth across the contiguous United States. Estimated spatial correlograms using data on four different measures of aggregate economic activity,population, employment, income, and earnings,over the period 1984,1994 indicate that cross-county interdependence is limited to relatively short ranges of distance. For each of the measures, the average correlation between the growth rates of two counties approaches zero within a range of approximately 200 miles. Moreover, the rate at which correlations decline with distance is not uniform. Inside of roughly 40 miles correlations show only a very slow rate of decline whereas beyond this range they drop off at a substantially higher rate. [source] A high-resolution radar experiment on the island of JerseyMETEOROLOGICAL APPLICATIONS, Issue 2 2007M. A. Rico-Ramirez Abstract A very high-resolution X-band vertically pointing weather radar was deployed in the island of Jersey, UK, from February to May 2004, to study the variation of the vertical reflectivity of precipitation (VPR) in this region. Intercomparison studies were carried out with a C-band scanning weather radar operated by Jersey Met. Department. C-band radar rainfall estimations and raingauge measurements were well correlated at very short ranges (<10 km), but there are clear difficulties in the estimation of precipitation due to ground clutter, and anomalous propagation echoes as well as the variation of VPR. Average VPRs were obtained from the X-band radar that helped reduce the bright band enhancement in C-band scanning weather radar measurements. This paper presents the overall results obtained during this radar experiment. The experiment was one of a series designed to understand the VPR and design removal algorithms for bright band contamination of quantitative radar measurements of precipitation. Copyright © 2007 Royal Meteorological Society [source] | |||||||||||||||||||