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Sample records for long-range chemical gradients

  1. Rapid generation of biologically relevant hydrogels containing long-range chemical gradients **

    PubMed Central

    He, Jiankang; Du, Yanan; Villa-Uribe, Jose L; Hwang, Changmo; Li, Dichen

    2010-01-01

    Many biological processes are regulated by gradients of bioactive chemicals. Thus, the generation of materials with embedded chemical gradients may be beneficial for understanding biological phenomena and generating tissue-mimetic constructs. Here we describe a simple and versatile method to rapidly generate materials containing centimeter-long gradients of chemical properties in a microfluidic channel. The formation of chemical gradient was initiated by a passive-pump-induced forward flow and further developed during an evaporation-induced backward flow. The gradient was spatially controlled by the backward flow time and the hydrogel material containing the gradient was synthesized via photopolymerization. Gradients of a cell-adhesion ligand, Arg-Gly-Asp-Ser (RGDS), was incorporated in the poly(ethylene glycol)-diacrylate (PEG-DA) hydrogels to test the response of endothelial cells. The cells attached and spread along the hydrogel material in a manner consistent with the RGDS gradient profile. A hydrogel containing PEG-DA concentration gradient and constant RGDS concentration was also generated. The morphology of cells cultured on such hydrogel changed from round in the lower PEG-DA concentration regions to well-spread in the higher PEG-DA concentration regions. This approach is expected to be a valuable tool to investigate the cell-material interactions in a simple and high-throughput manner and to design graded biomimetic materials for tissue engineering applications. PMID:20216924

  2. A diffusion based long-range and steady chemical gradient generator on a microfluidic device for studying bacterial chemotaxis

    NASA Astrophysics Data System (ADS)

    Murugesan, Nithya; Singha, Siddhartha; Panda, Tapobrata; Das, Sarit K.

    2016-03-01

    Studies on chemotaxis in microfluidics device have become a major area of research to generate physiologically similar environment in vitro. In this work, a novel micro-fluidic device has been developed to study chemo-taxis of cells in near physiological condition which can create controllable, steady and long-range chemical gradients using various chemo-effectors in a micro-channel. Hydrogels like agarose, collagen, etc, can be used in the device to maintain exclusive diffusive flux of various chemical species into the micro-channel under study. Variations of concentrations and flow rates of Texas Red dextran in the device revealed that an increase in the concentration of the dye in the feed from 6 to 18 μg ml-1, causes a steeper chemical gradient in the device, whereas the flow rate of the dye has practically no effect on the chemical gradient in the device. This observation confirms that a diffusion controlled chemical gradient is generated in the micro-channel. Chemo-taxis of E. coli cells were studied under the steady gradient of a chemo-attractant and a chemo-repellent separately in the same chemical gradient generator. For sorbitol and NiSO4·6H2O, the bacterial cells exhibit a steady distribution in the micro channel after 1 h and 30 min, respectively. From the distribution of bacterial population chemo-tactic strength of the chemo-effectors was estimated for E. coli. In a long microfluidic channel, migration behavior of bacterial cells under diffusion controlled chemical gradient showed chemotaxis, random movement, aggregation, and concentration dependent reverse chemotaxis.

  3. Convection driven generation of long-range material gradients

    PubMed Central

    Du, Yanan; Hancock, Matthew J.; He, Jiankang; Villa-Uribe, Jose; Wang, Ben; Cropek, Donald M.; Khademhosseini, Ali

    2009-01-01

    Natural materials exhibit anisotropy with variations in soluble factors, cell distribution, and matrix properties. The ability to recreate the heterogeneity of the natural materials is a major challenge for investigating cell-material interactions and for developing biomimetic materials. Here we present a generic fluidic approach using convection and alternating flow to rapidly generate multi-centimeter gradients of biomolecules, polymers, beads and cells and cross-gradients of two species in a microchannel. Accompanying theoretical estimates and simulations of gradient growth provide design criteria over a range of material properties. A poly(ethyleneglycol) hydrogel gradient, a porous collagen gradient and a composite material with a hyaluronic acid/gelatin cross-gradient were generated with continuous variations in material properties and in their ability to regulate cellular response. This simple yet generic fluidic platform should prove useful for creating anisotropic biomimetic materials and high-throughput platforms for investigating cell-microenvironment interaction. PMID:20035990

  4. Long-range order and dynamic structure factor of a nematic under a thermal gradient

    NASA Astrophysics Data System (ADS)

    Rodríguez, R. F.; Híjar, H.

    2006-03-01

    We use a fluctuating hydrodynamic approach to calculate the orientation fluctuations correlation functions of a thermotropic nematic liquid crystal in a nonequilibrium state induced by a stationary heat flux. Since in this nonequilibrium stationary state the hydrodynamic fluctuations evolve on three widely separated times scales, we use a time-scale perturbation procedure in order to partially diagonalize the hydrodynamic matrix. The wave number and frequency dependence of these orientation correlation functions is evaluated and their explicit functional form on position is also calculated analytically in and out of equilibrium. We show that for both states these correlations are long-ranged. This result shows that indeed, even in equilibrium there is long-range orientational order in the nematic, consistently with the well known properties of these systems.We also calculate the dynamic structure of the fluid in both states for a geometry consistent with light scattering experiments. We find that as with isotropic simple fluids, the external temperature gradient introduces an asymmetry in the spectrum shifting its maximum by an amount proportional to the magnitude of the gradient. This effect may be of the order of 7 per cent. Also, the width at half height may decrease by a factor of about 10 per cent. Since to our knowledge there are no experimental results available in the literature to compare with, the predictions of our model calculation remains to be assessed.

  5. Long-range electron transport in Geobacter sulfurreducens biofilms is redox gradient-driven

    PubMed Central

    Snider, Rachel M.; Strycharz-Glaven, Sarah M.; Tsoi, Stanislav D.; Erickson, Jeffrey S.; Tender, Leonard M.

    2012-01-01

    Geobacter spp. can acquire energy by coupling intracellular oxidation of organic matter with extracellular electron transfer to an anode (an electrode poised at a metabolically oxidizing potential), forming a biofilm extending many cell lengths away from the anode surface. It has been proposed that long-range electron transport in such biofilms occurs through a network of bound redox cofactors, thought to involve extracellular matrix c-type cytochromes, as occurs for polymers containing discrete redox moieties. Here, we report measurements of electron transport in actively respiring Geobacter sulfurreducens wild type biofilms using interdigitated microelectrode arrays. Measurements when one electrode is used as an anode and the other electrode is used to monitor redox status of the biofilm 15 μm away indicate the presence of an intrabiofilm redox gradient, in which the concentration of electrons residing within the proposed redox cofactor network is higher farther from the anode surface. The magnitude of the redox gradient seems to correlate with current, which is consistent with electron transport from cells in the biofilm to the anode, where electrons effectively diffuse from areas of high to low concentration, hopping between redox cofactors. Comparison with gate measurements, when one electrode is used as an electron source and the other electrode is used as an electron drain, suggests that there are multiple types of redox cofactors in Geobacter biofilms spanning a range in oxidation potential that can engage in electron transport. The majority of these redox cofactors, however, seem to have oxidation potentials too negative to be involved in electron transport when acetate is the electron source. PMID:22955881

  6. Long-range transport of Saharan dust and chemical transformations over the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Athanasopoulou, E.; Protonotariou, A.; Papangelis, G.; Tombrou, M.; Mihalopoulos, N.; Gerasopoulos, E.

    2016-09-01

    Three recent Saharan dust outbreaks during different seasons (4-6 days in winter of 2009, late autumn of 2010 and summer of 2011) are selected in order to study the chemical footprint and aging processes of dust intrusions over the Eastern Mediterranean (EM). The applied model system (PMCAMx, WRF and GEOS-CHEM) and methodology are found competent to reproduce dust production, long-range transport and chemical transformations over the EM, with the synergistic use of synoptic patterns analysis, optical depth retrievals, back-trajectories, surface and satellite aerosol measurements. The dust loads were high during the cold period events and much lighter during summertime, when transport was mainly in the free troposphere. In all cases, dust originated from the northwest and/or west Saharan desert and reached the EM from the west/southwest. Sensitivity runs underlie the effect of dust transport on the chemical constituents of aerosols over the EM and show a large impact on calcium (70-90% of maximum daily values 2-5 μg m-3), with its gradient at surface level being around -10% per 100 km along the dust pathway. For the cold period cases, this value can also be considered analogous to the dust dissipation ratio, because the plume is vertically extended down to the surface layers. Interestingly, the surface particulate nitrate concentrations over the EM are reversely affected by the approaching dust loads, exhibiting the highest values (up to 6 μg m-3) and the largest dust fraction (ca. 70%) during summertime. This is attributed to the enhanced nitric acid formation under high atmospheric temperature and insolation, its uptake onto the carbonate dust particles, and their effective accumulation, due to low deposition rates over the sea and scarce precipitation. Sulfate formation onto dust particles is found insignificant (rapid reaction with ammonia and/or sea-salt), while the influence of dust and sea-salt on sodium, when spatio-temporal averages are calculated, is

  7. Cellular interpretation of the long-range gradient of Four-jointed activity in the Drosophila wing

    PubMed Central

    Hale, Rosalind; Brittle, Amy L; Fisher, Katherine H; Monk, Nicholas A M; Strutt, David

    2015-01-01

    To understand how long-range patterning gradients are interpreted at the cellular level, we investigate how a gradient of expression of the Four-jointed kinase specifies planar polarised distributions of the cadherins Fat and Dachsous in the Drosophila wing. We use computational modelling to test different scenarios for how Four-jointed might act and test the model predictions by employing fluorescence recovery after photobleaching as an in vivo assay to measure the influence of Four-jointed on Fat-Dachsous binding. We demonstrate that in vivo, Four-jointed acts both on Fat to promote its binding to Dachsous and on Dachsous to inhibit its binding to Fat, with a bias towards a stronger effect on Fat. Overall, we show that opposing gradients of Fat and Dachsous phosphorylation are sufficient to explain the observed pattern of Fat–Dachsous binding and planar polarisation across the wing, and thus demonstrate the mechanism by which a long-range gradient is interpreted. DOI: http://dx.doi.org/10.7554/eLife.05789.001 PMID:25707557

  8. Atmospheric emissions and long-range transport of persistent organic chemicals

    NASA Astrophysics Data System (ADS)

    Scheringer, M.

    2010-12-01

    Persistent organic chemicals include several groups of halogenated compounds, such as polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), and polyfluorinated carboxylic acids (PFCAs). These chemicals remain for long times (years to decades) in the environment and cycle between different media (air, water, sediment, soil, vegetation, etc.). The environmental distribution of this type of chemicals can conveniently be analyzed by multimedia models. Multimedia models consist of a set of coupled mass balance equations for the environmental media considered; they can be set up at various scales from local to global. Two applications of multimedia models to airborne chemicals are discussed in detail: the day-night cycle of PCBs measured in air near the surface, and the atmospheric long-range transport of volatile precursors of PFCAs, formation of PFCAs by oxidation of these precursors, and subsequent deposition of PFCAs to the surface in remote regions such as the Arctic.

  9. Chemical and Aerosol Signatures of Biomass Burning via Long Range Transport observed at Storm Peak Laboratory

    NASA Astrophysics Data System (ADS)

    Hallar, A. G.; Obrist, D.; McCubbin, I. B.; Fain, X.; Rahn, T.

    2008-12-01

    The Desert Research Institute operates a high elevation facility, Storm Peak Laboratory (SPL), located on the Steamboat Springs Ski Resort in Colorado at an elevation 3.2 km. During the spring of 2008, two field projects were conducted at SPL; Storm Peak Cloud and Aerosol Characterization (SPACC) and a State of Colorado Mercury Monitoring project. Measurements of gaseous elemental mercury (GEM), along with CO, ozone and aerosol concentrations and aerosol size distributions will be presented from April 28 to July 1st 2008. This work focuses on specific case studies pertaining to long range transport events. Specifically, high levels of GEM and CO will be presented from May 15, 2008. This data will be coupled with HYSPLIT backtrajectories, chemical modeling via MOZART, and satellite imagery (MODIS) to present evidence that Siberian wildfires impacted the air quality at Storm Peak Laboratory.

  10. Network of long-range concerted chemical shift displacements upon ligand binding to human angiogenin

    PubMed Central

    Gagné, Donald; Narayanan, Chitra; Doucet, Nicolas

    2015-01-01

    Molecular recognition models of both induced fit and conformational selection rely on coupled networks of flexible residues and/or structural rearrangements to promote protein function. While the atomic details of these motional events still remain elusive, members of the pancreatic ribonuclease superfamily were previously shown to depend on subtle conformational heterogeneity for optimal catalytic function. Human angiogenin, a structural homologue of bovine pancreatic RNase A, induces blood vessel formation and relies on a weak yet functionally mandatory ribonucleolytic activity to promote neovascularization. Here, we use the NMR chemical shift projection analysis (CHESPA) to clarify the mechanism of ligand binding in human angiogenin, further providing information on long-range intramolecular residue networks potentially involved in the function of this enzyme. We identify two main clusters of residue networks displaying correlated linear chemical shift trajectories upon binding of substrate fragments to the purine- and pyrimidine-specific subsites of the catalytic cleft. A large correlated residue network clusters in the region corresponding to the V1 domain, a site generally associated with the angiogenic response and structural stability of the enzyme. Another correlated network (residues 40–42) negatively affects the catalytic activity but also increases the angiogenic activity. 15N-CPMG relaxation dispersion experiments could not reveal the existence of millisecond timescale conformational exchange in this enzyme, a lack of flexibility supported by the very low-binding affinities and catalytic activity of angiogenin. Altogether, the current report potentially highlights the existence of long-range dynamic reorganization of the structure upon distinct subsite binding events in human angiogenin. PMID:25450558

  11. On chemical distances and shape theorems in percolation models with long-range correlations

    NASA Astrophysics Data System (ADS)

    Drewitz, Alexander; Ráth, Balázs; Sapozhnikov, Artëm

    2014-08-01

    In this paper, we provide general conditions on a one parameter family of random infinite subsets of {{Z}}^d to contain a unique infinite connected component for which the chemical distances are comparable to the Euclidean distance. In addition, we show that these conditions also imply a shape theorem for the corresponding infinite connected component. By verifying these conditions for specific models, we obtain novel results about the structure of the infinite connected component of the vacant set of random interlacements and the level sets of the Gaussian free field. As a byproduct, we obtain alternative proofs to the corresponding results for random interlacements in the work of Černý and Popov ["On the internal distance in the interlacement set," Electron. J. Probab. 17(29), 1-25 (2012)], and while our main interest is in percolation models with long-range correlations, we also recover results in the spirit of the work of Antal and Pisztora ["On the chemical distance for supercritical Bernoulli percolation," Ann Probab. 24(2), 1036-1048 (1996)] for Bernoulli percolation. Finally, as a corollary, we derive new results about the (chemical) diameter of the largest connected component in the complement of the trace of the random walk on the torus.

  12. On chemical distances and shape theorems in percolation models with long-range correlations

    SciTech Connect

    Drewitz, Alexander; Ráth, Balázs; Sapozhnikov, Artëm

    2014-08-01

    In this paper, we provide general conditions on a one parameter family of random infinite subsets of Z{sup d} to contain a unique infinite connected component for which the chemical distances are comparable to the Euclidean distance. In addition, we show that these conditions also imply a shape theorem for the corresponding infinite connected component. By verifying these conditions for specific models, we obtain novel results about the structure of the infinite connected component of the vacant set of random interlacements and the level sets of the Gaussian free field. As a byproduct, we obtain alternative proofs to the corresponding results for random interlacements in the work of Cerný and Popov [“On the internal distance in the interlacement set,” Electron. J. Probab. 17(29), 1–25 (2012)], and while our main interest is in percolation models with long-range correlations, we also recover results in the spirit of the work of Antal and Pisztora [“On the chemical distance for supercritical Bernoulli percolation,” Ann Probab. 24(2), 1036–1048 (1996)] for Bernoulli percolation. Finally, as a corollary, we derive new results about the (chemical) diameter of the largest connected component in the complement of the trace of the random walk on the torus.

  13. Chemical characteristics of Northeast Asian fly ash particles: Implications for their long-range transportation

    NASA Astrophysics Data System (ADS)

    Inoue, Jun; Momose, Azusa; Okudaira, Takamoto; Murakami-Kitase, Akiko; Yamazaki, Hideo; Yoshikawa, Shusaku

    2014-10-01

    The chemical compositions of fly ash particles emitted in Northeast Asia were studied to better understand the long-range transportation of atmospheric pollutants. We examined the compositions of spheroidal carbonaceous particles (SCPs), a type of fly ash from several to ˜20 μm in diameter found in surface sediments in or near the main industrial cities of Japan, China, South Korea, and Taiwan. SCPs from different countries were found to vary; SCPs from Japan and South Korea were characterized by low Ti/Si and high S/Si ratios, whereas SCPs in China exhibited high Ti/Si and low S/Si ratios and particles from Taiwan showed high Ti/Si and S/Si ratios. We also examined the SCPs found in remote islands in the Sea of Japan, at least 100 km from any industrial city. On the basis of their chemical compositions, these SCPs were classified as Japan and Korea, China, and Taiwan types using discriminant analysis. The results indicated that 30-50% of the particles found in these islands were assigned to the China type, suggesting that most of these SCPs were probably transported from Chinese industrial regions to these islands. It implies that even large particulate pollutants of ˜10 μm, such as SCPs, could be transported long distances of ˜1000 km.

  14. Chemical reactivity and long-range transport potential of polycyclic aromatic hydrocarbons--a review.

    PubMed

    Keyte, Ian J; Harrison, Roy M; Lammel, Gerhard

    2013-12-21

    Polycyclic aromatic hydrocarbons (PAHs) are of considerable concern due to their well-recognised toxicity and especially due to the carcinogenic hazard which they present. PAHs are semi-volatile and therefore partition between vapour and condensed phases in the atmosphere and both the vapour and particulate forms undergo chemical reactions. This article briefly reviews the current understanding of vapour-particle partitioning of PAHs and the PAH deposition processes, and in greater detail, their chemical reactions. PAHs are reactive towards a number of atmospheric oxidants, most notably the hydroxyl radical, ozone, the nitrate radical (NO3) and nitrogen dioxide. Rate coefficient data are reviewed for reactions of lower molecular weight PAH vapour with these species as well as for heterogeneous reactions of higher molecular weight compounds. Whereas the data for reactions of the 2-3-ring PAH vapour are quite extensive and generally consistent, such data are mostly lacking for the 4-ring PAHs and the heterogeneous rate data (5 and more rings), which are dependent on the substrate type and reaction conditions, are less comprehensive. The atmospheric reactions of PAH lead to the formation of oxy and nitro derivatives, reviewed here, too. Finally, the capacity of PAHs for long range transport and the results of numerical model studies are described. Research needs are identified. PMID:24077263

  15. Fabrication of long-range surface plasmon polaritons waveguide by wet chemical etching

    NASA Astrophysics Data System (ADS)

    Xie, Ying; Liu, Tong; Zhao, Xuliang; Zhang, Meiling; Chen, Changming; Wang, Fei; Sun, Xiaoqiang; Zhang, Daming

    2014-06-01

    The fabrication of long-range surface plasmon polaritons (LRSPPs) waveguides based on a thin Au stripe embedded in poly(methyl-methacrylate-glycidly-methacrylate) polymers was investigated. By patterning the photoresist, a wet chemical etching technique was used to avoid sharp pin-like and shark-fin-like structures on the edges of the Au stripe. The surface morphology of the Au film and polymer cladding were studied by atomic force microscopy (AFM), as well as by using the waveguide configuration of the Au stripe. AFM images proved the elimination of parasitic structures. A 2 cm long, 4 μm wide, and 25 nm thick Au stripe waveguide exhibited a propagation loss of approximately 4.3 dB cm-1 measured by the cut-back method and end-fire excitation of LRSPP mode guiding at 1550 nm. The demonstration of optical signal transmission indicates that the LRSPP waveguide fabricated by wet chemical etching is a potential solution to on-chip optical interconnections.

  16. Long-range standoff detection of chemical, biological, and explosive hazards on surfaces

    NASA Astrophysics Data System (ADS)

    Fountain, Augustus Way, III; Guicheteau, Jason A.; Pearman, William F.; Chyba, Thomas H.; Christesen, Steven D.

    2010-04-01

    Fielded surface detection systems rely on contact with either the liquid contamination itself or the associated chemical vapor above the contaminated surface and do not provide a standoff or remote detection capability. Conversely, standoff chemical vapor sensing techniques have not shown efficacy in detecting those contaminants as liquids or solids on surfaces. There are a number of optical or spectroscopic techniques that could be applied to this problem of standoff chemical detection on surfaces. The three techniques that have received the most interest and development are laser induced breakdown spectroscopy (LIBS), fluorescence, and Raman spectroscopy. Details will be presented on the development of these techniques and their applicability to detecting CBRNE contamination on surfaces.

  17. Long range standoff detection of chemical and explosive hazards on surfaces

    NASA Astrophysics Data System (ADS)

    Fountain, Augustus Way, III; Christesen, Steven D.; Guicheteau, Jason A.; Pearman, William F.; Chyba, Tom

    2009-09-01

    Fielded surface detection systems rely on contact with either the liquid contamination itself or the associated chemical vapor above the contaminated surface and do not provide a standoff or remote detection capability. Conversely, standoff chemical vapor sensing techniques have not shown efficacy in detecting those contaminants as liquids or solids on surfaces. There are a number of optical or spectroscopic techniques that could be applied to this problem of standoff chemical detection on surfaces. The three techniques that have received the most interest and development are laser induced breakdown spectroscopy (LIBS), fluorescence, and Raman spectroscopy. Details will be presented on the development of these techniques and their applicability to detecting CBRNE contamination on surfaces.

  18. Long-range chemical orders in Au-Pd nanoparticles revealed by aberration-corrected electron microscopy.

    PubMed

    Nelayah, Jaysen; Nguyen, Nhat Tai; Alloyeau, Damien; Wang, Guillaume Yangshu; Ricolleau, Christian

    2014-09-01

    Despite the importance of gold-palladium nanoalloys in heterogeneous catalysis, the phase stability of Au-Pd alloys still remains unclear. We report here on the alloying and chemical ordering in epitaxially-grown and post-annealed gold-palladium nanoparticles (NPs) using aberration-corrected transmission electron microscopy. Au-Pd NPs with a controlled size, composition and structure were grown by pulsed laser deposition on freshly-cleaved NaCl(001) single crystals heated at 300 °C. After transfer to an amorphous carbon support, the NPs were annealed in vacuum at elevated temperatures above 400 °C for a few hours (6-10 hours) to promote chemical ordering. The as-grown NPs were mostly monocrystalline with a chemically-disordered face-centered cubic structure. Upon high-temperature annealing, a high degree of chemical ordering was observed in nanometer-sized NPs. Electron microscopy measurements showed that both L10 and L12 orders are stabilized in the Au-rich region of the Au-Pd phase diagram. These ordered phases exist at temperatures as high as 600 °C. Moreover, compositional analysis of single annealed particles revealed that the observed chemical ordering occurs in parallel to a two-tiered Ostwald ripening process. Due to this ripening process, a clear dependence between chemical composition and particle size is established during annealing with an enrichment in Pd as the NPs grow in size. Our results, besides clarifying some controversial aspects about long-range order in Au-Pd alloys, shed light on the structural stability of Au-Pd nanoalloys at elevated temperatures. PMID:25079393

  19. Implications of the chemical transformation of Asian outflow aerosols for the long-range transport of inorganic nitrogen species

    NASA Astrophysics Data System (ADS)

    Chou, Charles C.-K.; Lee, C. T.; Yuan, C. S.; Hsu, W. C.; Lin, C.-Y.; Hsu, S.-C.; Liu, S. C.

    To improve our understanding of the chemical characteristics of aerosols transported from the Asian continent to the western North Pacific, an aerosol observation network has been established in Taiwan. From the measurements made during 2003-2005, it was found that the aerosol concentrations in the continental outflows were much higher than those of remote areas, evidently due to the long-range transport of air pollutants and dust from the Asian continent. Analysis on the chemical compositions of aerosols revealed that the Asian outflow aerosols underwent chemical transformation and, consequently, became more abundant in ammonium and nitrate when they mixed with air pollutants originating from Taiwan. The NH 4+/SO 42- ratio in fine aerosols (PM2.5) increased from 1.55 at the Cape Fuguei, the northern tip of Taiwan, to 2.30 at Penghu, in the middle of the Taiwan Strait. The increased NH 4+/SO 42- ratio implied that the acidity of the sulfate aerosols in Asian outflows was totally neutralized by ammonia as the aerosols traveled through the North Taiwan and its vicinity. In addition, the analysis indicated that the chlorine deficiency of sea salt aerosols was higher at the southern stations than at the Cape Fuguei. The chlorine deficiency was attributed to the heterogeneous reaction of NaCl and HNO 3(g), which means that the oxidation of SO 2 in sea spray droplets was inhibited. Moreover, uptake of secondary acids by the dust particles was observed. The results of this study suggested that the Asian outflow aerosols are important carriers of gaseous inorganic nitrogen species, particularly nitric acid and ammonia, in this region. Hence the atmospheric deposition of soluble inorganic nitrogen could become enhanced in the northern South China Sea, which is downwind of Taiwan during the periods of Asian winter monsoons.

  20. Thermo-chemical structure of the lithospheric mantle underneath the Siberian craton inferred from long-range seismic profiles

    NASA Astrophysics Data System (ADS)

    Kuskov, O. L.; Kronrod, V. A.; Prokofyev, A. A.; Pavlenkova, N. I.

    2014-03-01

    Based on a self-consistent thermodynamic-geophysical approach and xenolith-based constraints, we map the 2-D seismic, thermal and density structure of the mantle beneath the Siberian craton along the long-range profiles (Craton, Kimberlite, Rift and Meteorite) carried out in Russia with peaceful nuclear explosions. Structural peculiarities of the cratonic mantle are manifested by changes in seismic velocities, the degree and nature of layering and the relief of seismic boundaries. The results predict appreciable lateral temperature variations within the root to a depth of about 200 km, which are the main cause of seismic velocity variations. We find that the cratonic mantle is 300-400 °C colder than the tectonically younger surrounding mantle in this depth range. At greater depths, lateral changes in temperatures have little effect implying that thermal heterogeneity rapidly decreases. The present-day geotherms pass close to the 32.5-35 mW m- 2 conductive models and suggest low mantle heat flow. Within the model resolution, the thickness of the thermal boundary layer, TBL (defined as the depth of the 1300 °C adiabat) beneath Siberia does not depend significantly on the composition and can be estimated as 300 ± 30 km; temperature at the base of the TBL is close to the 1450 ± 100 °C isotherm. Changes in the composition from depleted to fertile material reveal a negligible effect on seismic velocities, which are practically unresolved by seismic methods, but remain the most important factor for the density increase of the cratonic root. Density variations in the lower part of the root due to the chemical composition are greater than those caused by temperature. We find that both compositional and thermal anomalies are required to explain the Siberian mantle by a keel model consisting of depleted garnet peridotite at depths of 100 to 180 km and more fertile material at greater depths.

  1. Long Range Technology Planning.

    ERIC Educational Resources Information Center

    Ambron, Sueann, Ed.

    1986-01-01

    This summary of a meeting of the Apple Education Advisory Council, on long range technology plans at the state, county, district, and school levels, includes highlights from group discussions on future planning, staff development, and curriculum. Three long range technology plans at the state level are provided: Long Range Educational Technology…

  2. Development of frequency-agile high-repetition-rate CO{sub 2} DIAL systems for long range chemical remote sensing

    SciTech Connect

    Quick, C.R. Jr.; Fite, C.B.; Foy, B.R.; Jolin, J.; Mietz, D.E.

    1997-11-01

    Issues related to the development of direct detection, long-range CO{sub 2} DIAL systems for chemical detection and identification are presented and discussed including: data handling and display techniques for large, multi-{lambda} data sets, turbulence effects, slant path propagation, and speckle averaging. Data examples from various field campaigns and CO{sub 2} lidar platforms are used to illustrate the issues.

  3. Long-Range Chemical Sensitivity in the Sulfur K-Edge X-ray Absorption Spectra of Substituted Thiophenes

    PubMed Central

    2015-01-01

    Thiophenes are the simplest aromatic sulfur-containing compounds and are stable and widespread in fossil fuels. Regulation of sulfur levels in fuels and emissions has become and continues to be ever more stringent as part of governments’ efforts to address negative environmental impacts of sulfur dioxide. In turn, more effective removal methods are continually being sought. In a chemical sense, thiophenes are somewhat obdurate and hence their removal from fossil fuels poses problems for the industrial chemist. Sulfur K-edge X-ray absorption spectroscopy provides key information on thiophenic components in fuels. Here we present a systematic study of the spectroscopic sensitivity to chemical modifications of the thiophene system. We conclude that while the utility of sulfur K-edge X-ray absorption spectra in understanding the chemical composition of sulfur-containing fossil fuels has already been demonstrated, care must be exercised in interpreting these spectra because the assumption of an invariant spectrum for thiophenic forms may not always be valid. PMID:25116792

  4. Investigating long-range transport of pollution to the Arctic troposphere using aircraft observations and a global chemical transport model

    NASA Astrophysics Data System (ADS)

    Monks, S.; Arnold, S.; Chipperfield, M.; Turquety, S.; Ancellet, G.; Law, K.; Schlager, H.

    2009-04-01

    Surface temperatures in the Arctic have increased more than in any other region over the past few decades. A better understanding of the processes governing this warming, including the role of short-lived greenhouse gases, is therefore urgently required. During summer 2008, the POLARCAT campaign aimed to collect an extensive gas-phase and aerosol dataset within the Arctic troposphere, which will aid the evaluation of our understanding of oxidant photochemistry and aerosol processing in the region. Previous comparisons of global chemical transport models have shown that they exhibit large variability in their Arctic chemical budgets, indicating that the processes controlling Arctic tropospheric composition are not well understood or represented within models. Here, we will use new trace-gas observations from the French ATR and German DLR Falcon aircraft during the POLARCAT experiment to evaluate the ability of a global chemical transport model (TOMCAT) to simulate the summertime transport of pollutants to the Arctic, and their impact on oxidant budgets. In particular, we aim to quantify the impact of anthropogenic and biomass burning sources on the Arctic tropospheric ozone budget. Initial results show that the model underestimates observed concentrations of CO which has led to a re-evaluation of the different sources of CO to the region. Model performance in the Arctic is highly sensitive to the treatment of boreal biomass burning emissions. Boreal biomass burning plumes were sampled frequently over the course of the campaign therefore accurate representation of emission injection heights and fire locations is essential. Model CO is improved with real-time satellite derived daily biomass burning emissions, however large uncertainties in these emissions result in large variability in the Arctic CO budget. We will also present results on the ability of the model to capture pollution transport pathways to the Arctic and contributions to the oxidant and NOy budgets

  5. A new multimedia contaminant fate model for China: how important are environmental parameters in influencing chemical persistence and long-range transport potential?

    PubMed

    Zhu, Ying; Price, Oliver R; Tao, Shu; Jones, Kevin C; Sweetman, Andy J

    2014-08-01

    We present a new multimedia chemical fate model (SESAMe) which was developed to assess chemical fate and behaviour across China. We apply the model to quantify the influence of environmental parameters on chemical overall persistence (POV) and long-range transport potential (LRTP) in China, which has extreme diversity in environmental conditions. Sobol sensitivity analysis was used to identify the relative importance of input parameters. Physicochemical properties were identified as more influential than environmental parameters on model output. Interactive effects of environmental parameters on POV and LRTP occur mainly in combination with chemical properties. Hypothetical chemicals and emission data were used to model POV and LRTP for neutral and acidic chemicals with different KOW/DOW, vapour pressure and pKa under different precipitation, wind speed, temperature and soil organic carbon contents (fOC). Generally for POV, precipitation was more influential than the other environmental parameters, whilst temperature and wind speed did not contribute significantly to POV variation; for LRTP, wind speed was more influential than the other environmental parameters, whilst the effects of other environmental parameters relied on specific chemical properties. fOC had a slight effect on POV and LRTP, and higher fOC always increased POV and decreased LRTP. Example case studies were performed on real test chemicals using SESAMe to explore the spatial variability of model output and how environmental properties affect POV and LRTP. Dibenzofuran released to multiple media had higher POV in northwest of Xinjiang, part of Gansu, northeast of Inner Mongolia, Heilongjiang and Jilin. Benzo[a]pyrene released to the air had higher LRTP in south Xinjiang and west Inner Mongolia, whilst acenaphthene had higher LRTP in Tibet and west Inner Mongolia. TCS released into water had higher LRTP in Yellow River and Yangtze River catchments. The initial case studies demonstrated that SESAMe

  6. Observation of chemical modification of Asian Dust particles during long-range transport by the combined use of quantitative ED-EPMA and ATR-FT-IR imaging

    NASA Astrophysics Data System (ADS)

    Song, Young-Chul; Eom, Hyo-Jin; Jung, Hae-Jin; Malek, Md Abdul; Kim, HyeKyeong; Ro, Chul-Un

    2012-10-01

    In our previous works, it was demonstrated that the combined use of quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA), which is also known as low-Z particle EPMA, and attenuated total reflectance FT-IR (ATR-FT-IR) imaging has great potential for a detailed characterization of individual aerosol particles. In this study, individual Asian Dust particles collected during an Asian Dust storm event on 11 November 2011 in Korea were characterized by the combined use of low-Z particle EPMA and ATR-FT-IR imaging. The combined use of the two single-particle analytical techniques on the same individual particles showed that Asian Dust particles had experienced extensive chemical modification during long-range transport. Overall, 109 individual particles were classified into four particle types based on their morphology, elemental concentrations, and molecular species and/or functional groups of individual particles available from the two analytical techniques: Ca-containing (38%); NaNO3-containing (30%); silicate (22%); and miscellaneous particles (10%). Among the 41 Ca-containing particles, 10, 8, and 14 particles contained nitrate, sulfate, and both, respectively, whereas only two particles contained unreacted CaCO3. Airborne amorphous calcium carbonate (ACC) particles were observed in this Asian Dust sample for the first time, where their IR peaks for the insufficient symmetric environment of CO32- ions of ACC were clearly differentiated from those of crystalline CaCO3. This paper also reports the field observations of CaCl2 particles converted from CaCO3 for the Asian Dust sample collected in the planetary boundary layer. Thirty three particles contained NaNO3, which are the reaction products of sea-salt and NOx/HNO3, whereas no genuine sea-salt particles were encountered, indicating that sea-salt particles are more reactive than CaCO3 particles. Some silicate particles were observed to contain nitrate, sulfate, and water. Among 24 silicate

  7. Results of joint processing of data on nuclear and chemical explosions recorded on the long-range Quartz profile (Murmansk-Kyzyl)

    NASA Astrophysics Data System (ADS)

    Pavlenkova, G. A.; Pavlenkova, N. I.

    2008-04-01

    The long-range seismic profile Quartz, measured by the GEON Center (Ministry of Geology of the USSR), crosses a few large geostructures: the East European platform, Timan-Pechora plate, Northern Urals, West Siberian plate (WSP), and Altai. Observations of nuclear and chemical explosions were conducted on the profile. Joint processing of records from sources of both types provided detailed structures of the crust and upper mantle. They have confirmed the known patterns in the structure of these shells of the Earth and revealed new ones. Mountain roots are observed beneath the Urals and Altai, and areas of a higher heat flow are matched by lower velocity zones in the upper mantle. Moreover, it is shown that the Timan-Pechora plate is characterized by a two-layer crust untypical of other young plates of central Eurasia and the upper mantle has the same velocities beneath the ancient East European platform and the young Altai orogen. It is also shown that the vast region including the Timan-Pechora plate, Urals, and WSP is bounded on both sides by deep faults in the upper mantle dipping toward the center of Western Siberia. A few nearly continuous reflectors traceable in the upper mantle are represented by thin-layered heterogeneous beds. The largest horizontal heterogeneity is observed in the upper 100-km layer, often underlain by a lower velocity zone. The asthenosphere, as a layer of lower seismic velocities at the depth of a possible solidus (200 250 km), has not been revealed. The latter is evidently a feature specific to inner parts of the Eurasian continent; in marginal regions, e.g., in Western Europe, the asthenospheric layer is identified almost ubiquitously.

  8. Institutional Long-Range Planning.

    ERIC Educational Resources Information Center

    Bolin, John G.

    This booklet presents a general outline for conducting a long-range planning study that can be adapted for use by any institution of higher education. The basic components of an effective long-range plan should include: (1) purposes of the plan, which define the scope of the study and provide the setting in which it will be initiated; (2) a set of…

  9. Density Gradient Columns for Chemical Displays.

    ERIC Educational Resources Information Center

    Guenther, William B.

    1986-01-01

    Procedures for preparing density gradient columns for chemical displays are presented. They include displays illustrating acid-base reactions, metal ion equilibria, and liquid density. The lifetime of these metastable displays is surprising, some lasting for months in display cabinets. (JN)

  10. Ratchetaxis: Long-Range Directed Cell Migration by Local Cues.

    PubMed

    Caballero, David; Comelles, Jordi; Piel, Matthieu; Voituriez, Raphaël; Riveline, Daniel

    2015-12-01

    Directed cell migration is usually thought to depend on the presence of long-range gradients of either chemoattractants or physical properties such as stiffness or adhesion. However, in vivo, chemical or mechanical gradients have not systematically been observed. Here we review recent in vitro experiments, which show that other types of spatial guidance cues can bias cell motility. Introducing local geometrical or mechanical anisotropy in the cell environment, such as adhesive/topographical microratchets or tilted micropillars, show that local and periodic external cues can direct cell motion. Together with modeling, these experiments suggest that cell motility can be viewed as a stochastic phenomenon, which can be biased by various types of local cues, leading to directional migration. PMID:26615123

  11. Long-range electron transfer

    PubMed Central

    Gray, Harry B.; Winkler, Jay R.

    2005-01-01

    Recent investigations have shed much light on the nuclear and electronic factors that control the rates of long-range electron tunneling through molecules in aqueous and organic glasses as well as through bonds in donor–bridge–acceptor complexes. Couplings through covalent and hydrogen bonds are much stronger than those across van der Waals gaps, and these differences in coupling between bonded and nonbonded atoms account for the dependence of tunneling rates on the structure of the media between redox sites in Ru-modified proteins and protein–protein complexes. PMID:15738403

  12. Long-range atmospheric predictability

    NASA Astrophysics Data System (ADS)

    Reichler, Thomas Josef

    This study investigated the prospects and limits of global atmospheric predictability on the long range (beyond 2 weeks). Forecasting the atmosphere at this range is very challenging since elements of both weather and climate prediction enter the problem. The basic questions were: (1) how large is long-range predictability with perfect model and data; (2) how sensitive is such predictability to uncertainties in model and data; (3) which atmospheric processes are related to this predictability? These questions were answered through numerical experiments with an atmospheric general circulation model which is forced with different combinations of initial and boundary conditions. In particular, four tasks were accomplished: First, temporal variations of predictability and its relationship to initial and boundary conditions were examined. On average, initial conditions dominated predictability for the first 4 weeks, improved predictability for 6 weeks, and influenced predictability for 8 weeks. These time scales varied with season, region, and strength of the external forcing. Second, the global 3-dimensional structure of predictability was examined. Boundary forcing dominated over the tropics, and over the two main teleconnection regions in the North and South Pacific. Initial conditions influenced predictability almost everywhere, in particular when the external forcing was weak. This was mostly related to atmospheric persistence, which in turn was linked to low-frequency variability of major atmospheric modes. Third, predictability in the tropics was investigated for monthly means. Boundary forcing is generally dominating for this time scale, and its quality is crucial. The atmospheric response was strongly asymmetric to SST forcing, which suggests that tropical convection has a positive self-amplifying feedback. Initial conditions were also important, in particular over the Eastern Hemisphere. This was related to strong persistence of the divergent circulation and

  13. Space - The long range future

    NASA Technical Reports Server (NTRS)

    Von Puttkamer, J.

    1985-01-01

    Space exploration goals for NASA in the year 2000 time frame are examined. A lunar base would offer the opportunity for continuous earth viewing, further cosmogeochemical exploration and rudimentary steps at self-sufficiency in space. The latter two factors are also compelling reasons to plan a manned Mars base. Furthermore, competition and cooperation in a Mars mission and further interplanetary exploration is an attractive substitute for war. The hardware requirements for various configurations of Mars missions are briefly addressed, along with other, unmanned missions to the asteroid belt, Mercury, Venus, Jupiter and the moons of Jupiter and Saturn. Finally, long-range technological requirements for providing adequate living/working facilities for larger human populations in Space Station environments are summarized.

  14. Long range fast tool servo

    NASA Astrophysics Data System (ADS)

    Moorefield, G. M., II; Dow, Thomas A.; Falter, Karl J.; Ro, Paul I.

    1993-05-01

    The PEC's MAC 100 Fast Tool Servo (FTS) System has demonstrated the efficacy of fabricating off-axis parabolic segments on axis by utilizing a fast tool motion to machine non-rotationally symmetric surfaces. The key to this technique was a servo for the tool motion that had a high-bandwidth coupled with a small range of motion. The Keck telescope, with its thirty-six (36) 1-meter diameter segments, would have been an excellent application for this technology. Since this technology was not available at the time of construction, each mirror segment was fabricated to its desired shape by loading it to a specified deformed shape and polishing it to a spherical contour, then removing the bending loads to allow the segment to relax to the desired asymmetric shape. If the segments of this optic had been constructed on axis with an FTS, the fabrication of the most extreme segment would have required only about 200 micrometers of non-rotational symmetry. However, the demand for larger displacement actuators is being driven by new applications with nonrotationally symmetric components in the millimeter range. This report describes the search for a suitable actuator for a long range fast tool servo system that would allow the fabrication of non-rotationally symmetric optical surfaces with a 1 mm range of servo motion. To allow cost-effective machining of these surfaces, the actuator must also possess a 50 Hz bandwidth (minimum) and 25 nanometer resolution.

  15. A Cellular System for Spatial Signal Decoding in Chemical Gradients.

    PubMed

    Hegemann, Björn; Unger, Michael; Lee, Sung Sik; Stoffel-Studer, Ingrid; van den Heuvel, Jasmin; Pelet, Serge; Koeppl, Heinz; Peter, Matthias

    2015-11-23

    Directional cell growth requires that cells read and interpret shallow chemical gradients, but how the gradient directional information is identified remains elusive. We use single-cell analysis and mathematical modeling to define the cellular gradient decoding network in yeast. Our results demonstrate that the spatial information of the gradient signal is read locally within the polarity site complex using double-positive feedback between the GTPase Cdc42 and trafficking of the receptor Ste2. Spatial decoding critically depends on low Cdc42 activity, which is maintained by the MAPK Fus3 through sequestration of the Cdc42 activator Cdc24. Deregulated Cdc42 or Ste2 trafficking prevents gradient decoding and leads to mis-oriented growth. Our work discovers how a conserved set of components assembles a network integrating signal intensity and directionality to decode the spatial information contained in chemical gradients. PMID:26585298

  16. Long-range neural synchrony in behavior.

    PubMed

    Harris, Alexander Z; Gordon, Joshua A

    2015-07-01

    Long-range synchrony between distant brain regions accompanies multiple forms of behavior. This review compares and contrasts the methods by which long-range synchrony is evaluated in both humans and model animals. Three examples of behaviorally relevant long-range synchrony are discussed in detail: gamma-frequency synchrony during visual perception, hippocampal-prefrontal synchrony during working memory, and prefrontal-amygdala synchrony during anxiety. Implications for circuit mechanism, translation, and clinical relevance are discussed. PMID:25897876

  17. Long-range neural synchrony in behavior

    PubMed Central

    Harris, Alexander Z.; Gordon, Joshua A.

    2015-01-01

    Long-range synchrony between distant brain regions accompanies multiple forms of behavior. This review compares and contrasts the methods by which long-range synchrony is evaluated in both humans and model animals. Three examples of behaviorally-relevant long-range synchrony are discussed in detail: gamma-frequency synchrony during visual perception; hippocampal-prefrontal synchrony during working memory; and prefrontal-amygdala synchrony during anxiety. Implications for circuit mechanism, translation, and clinical relevance are discussed. PMID:25897876

  18. 1995-1998 Long Range Plan.

    ERIC Educational Resources Information Center

    Pennsylvania Coll. of Technology, Williamsport.

    At Pennsylvania College of Technology (PCT), in Williamsport, long range planning is used to define institutional philosophy and mission and determine strategies to make the best use of available resources and implement actions to fulfill institutional mission. This document presents PCT's long-range plan for 1995-98 in three parts. Following an…

  19. Long Range Plan: 1992-1995.

    ERIC Educational Resources Information Center

    Pennsylvania Coll. of Technology, Williamsport.

    Intended to enhance strategic planning and enable staff to work as a team toward a shared vision and common goals, this report presents the 1992-95 long-range plan of the Pennsylvania College of Technology (PCT). Part I defines long-range planning; describes the structure and use of the plan at PCT; presents PCT's philosophy, mission, and vision…

  20. Long Range Plan, 1991-1994.

    ERIC Educational Resources Information Center

    Pennsylvania Coll. of Technology, Williamsport.

    This long-range plan for the Pennsylvania College of Technology (PCT) is divided into three main sections. Part I provides an overview of planning at PCT, including a definition of long-range planning, the college philosophy, mission, and vision statements, major institutional initiatives for 1991-92, and accreditation agency recommendations…

  1. Long Range Plan, 1997-2000.

    ERIC Educational Resources Information Center

    Pennsylvania Coll. of Technology, Williamsport. Office of Strategic Planning and Research.

    At Pennsylvania College of Technology (PCT), long range planning is used to define institutional philosophy and mission and determine strategies to make the best use of available resources and implement actions to fulfill institutional mission. This document presents PCT's long-range plan for 1997-2000 in three parts. The first part describes long…

  2. Assessment of a long-range corrected hybrid functional

    SciTech Connect

    Vydrov, Oleg A.; Scuseria, Gustavo E.

    2006-12-21

    Common approximate exchange-correlation functionals suffer from self-interaction error, and as a result, their corresponding potentials have incorrect asymptotic behavior. The exact asymptote can be imposed by introducing range separation into the exchange component and replacing the long-range portion of the approximate exchange by the Hartree-Fock counterpart. The authors show that this long-range correction works particularly well in combination with the short-range variant of the Perdew-Burke-Ernzerhof (PBE) exchange functional. This long-range-corrected hybrid, here denoted LC-{omega}PBE, is remarkably accurate for a broad range of molecular properties, such as thermochemistry, barrier heights of chemical reactions, bond lengths, and most notably, description of processes involving long-range charge transfer.

  3. Chemical Abundance Gradients in the Star-forming Ring Galaxies

    NASA Astrophysics Data System (ADS)

    Korchagin, Vladimir; Vorobyov, Eduard; Mayya, Y. D.

    1999-09-01

    Ring waves of star formation, propagating outward in the galactic disks, leave chemical abundance gradients in their wakes. We show that the relative [Fe/O] abundance gradients in ring galaxies can be used as a tool for determining the role of the SN Ia explosions in their chemical enrichment. We consider two mechanisms--a self-induced wave and a density wave--that can create outwardly propagating star-forming rings in a purely gaseous disk and demonstrate that the radial distribution of the relative [Fe/O] abundance gradients depends neither on the particular mechanism of the wave formation anor on the parameters of the star-forming process. We show that the [Fe/O] profile is determined by the velocity of the wave, the initial mass function, and the initial chemical composition of the star-forming gas. If the role of SN Ia explosions is negligible in the chemical enrichment, the ratio [Fe/O] remains constant throughout the galactic disk with a steep gradient at the wave front. If SN Ia stars are important in the production of cosmic iron, the [Fe/O] ratio has a gradient in the wake of the star-forming wave with the value depending on the frequency of SN Ia explosions.

  4. Topological defects with long-range interactions

    NASA Astrophysics Data System (ADS)

    Mello, B. A.; González, J. A.; Guerrero, L. E.; López-Atencio, E.

    1998-07-01

    We investigate a modified sine-Gordon equation which possesses soliton solutions with long-range interaction. We introduce a generalized version of the Ginzburg-Landau equation which supports long-range topological defects in D = 1 and D > 1. The interaction force between the defects decays so slowly that it is possible to enter the non-extensivity regime. These results can be applied to non-equilibrium systems, pattern formation and growth models.

  5. Photon assisted long-range tunneling

    SciTech Connect

    Gallego-Marcos, Fernando; Sánchez, Rafael; Platero, Gloria

    2015-03-21

    We analyze long-range transport through an ac driven triple quantum dot with a single electron. Resonant transitions between separated and detuned dots are mediated by the exchange of n photons with the time-dependent field. An effective model is proposed in terms of second order (cotunneling) processes which dominate the long-range transport between the edge quantum dots. The ac field renormalizes the inter dot hopping, modifying the level hybridization. It results in a non-trivial behavior of the current with the frequency and amplitude of the external ac field.

  6. Passive long range acousto-optic sensor

    NASA Astrophysics Data System (ADS)

    Slater, Dan

    2006-08-01

    Alexander Graham Bell's photophone of 1880 was a simple free space optical communication device that used the sun to illuminate a reflective acoustic diaphragm. A selenium photocell located 213 m (700 ft) away converted the acoustically modulated light beam back into sound. A variation of the photophone is presented here that uses naturally formed free space acousto-optic communications links to provide passive multichannel long range acoustic sensing. This system, called RAS (remote acoustic sensor), functions as a long range microphone with a demonstrated range in excess of 40 km (25 miles).

  7. Photon assisted long-range tunneling

    NASA Astrophysics Data System (ADS)

    Gallego-Marcos, Fernando; Sánchez, Rafael; Platero, Gloria

    2015-03-01

    We analyze long-range transport through an ac driven triple quantum dot with a single electron. Resonant transitions between separated and detuned dots are mediated by the exchange of n photons with the time-dependent field. An effective model is proposed in terms of second order (cotunneling) processes which dominate the long-range transport between the edge quantum dots. The ac field renormalizes the inter dot hopping, modifying the level hybridization. It results in a non-trivial behavior of the current with the frequency and amplitude of the external ac field.

  8. Swarming behavior of gradient-responsive colloids with chemical signaling.

    PubMed

    Grančič, Peter; Štěpánek, František

    2013-07-01

    The article describes swarm dynamics of a system composed of colloidal particles that release chemical signals to navigate their peers toward the location of a static point target in two dimensions. The time evolution of the system is calculated by employing a combination of Brownian dynamics method for the particle motion and the diffusion problem for spatial transport of chemical signals, coupled via diffusiophoresis. A parametric study is performed with respect to crucial model parameters that control the diffusivity of the particles and the chemical signals. This includes the initial concentration of chemical signals carried by the particles, the chemical signal release rate, the diffusion coefficient of the chemical signals, the diffusiophoretic mobility of the particles, and the topological complexity of the surrounding environment. Three measures are used to evaluate the performance of the system: the target arrival time, the target localization success rate, and the target residence time. Since the particle motion is determined by the local concentration gradients of the chemical signals, parameter values that result in steep and durable concentration gradients lead to the best performance in navigating a swarm of colloidal particles toward the target. However, the results show that a trade-off principle exists, as it is not always possible to improve all the performance criteria simultaneously. For a topologically complex environment, the particles often become trapped in areas where the chemical signals accumulate, leading to a significant decrease in the localization success rate. PMID:23734621

  9. Long-Range Plan, 1978-83.

    ERIC Educational Resources Information Center

    Jonas, Stephen

    This nine-part, long-range plan discusses the internal and external factors that will affect Lorain County Community College's (LCCC's) development from 1978 to 1983 and presents a forecast of LCCC's future needs. Part I traces the history of LCCC, provides a conceptual framework for college planning, and discusses the plan development process…

  10. Discussion of long-range weather prediction

    SciTech Connect

    Canavan, G.H.

    1998-09-10

    A group of scientists at Los Alamos have held a series of discussions of the issues in and prospects for improvements in Long-range Weather Predictions Enabled by Proving of the Atmosphere at High Space-Time Resolution. The group contained the requisite skills for a full evaluation, although this report presents only an informal discussion of the main technical issues. The group discussed all aspects of the proposal, which are grouped below into the headings: (1) predictability; (2) sensors and satellites, (3) DIAL and atmospheric sensing; (4) localized transponders; and (5) summary and integration. Briefly, the group agreed that the relative paucity of observations of the state of the atmosphere severely inhibits the accuracy of weather forecasts, and any program that leads to a more dense and uniform observational network is welcome. As shown in Long-range Weather more dense and uniform observational network is welcome. As shown in Long-range Weather Predictions, the pay-back of accurate long-range forecasts should more than justify the expenditure associated with improved observations and forecast models required. The essential step is to show that the needed technologies are available for field test and space qualification.

  11. College and University Long-Range Planning.

    ERIC Educational Resources Information Center

    Haas, Raymond M.

    The system for long-range planning at West Virginia University is described, with emphasis on how it relates to short-range planning and how it is carried out operationally. Planning tools used include (1) an inventory of the past and present of the institution, (2) a statement of the division of labor within the institution and the objectives of…

  12. Resources and Long-Range Forecasts

    ERIC Educational Resources Information Center

    Smith, Waldo E.

    1973-01-01

    The author argues that forecasts of quick depletion of resources in the environment as a result of overpopulation and increased usage may not be free from error. Ignorance still exists in understanding the recovery mechanisms of nature. Long-range forecasts are likely to be wrong in such situations. (PS)

  13. Look Ahead: Long-Range Learning Plans

    ERIC Educational Resources Information Center

    Weinstein, Margery

    2010-01-01

    Faced with an unsteady economy and fluctuating learning needs, planning a learning strategy designed to last longer than the next six months can be a tall order. But a long-range learning plan can provide a road map for success. In this article, four companies (KPMG LLP, CarMax, DPR Construction, and EMC Corp.) describe their learning plans, and…

  14. Chemical gradients and progressive veining in a partly serpentinized harzburgite

    NASA Astrophysics Data System (ADS)

    Schwarzenbach, Esther; Caddick, Mark; Beard, James; Bodnar, Robert

    2016-04-01

    Serpentinized ultramafic rocks constitute a major part of the oceanic lithosphere. They form when water interacts with olivine and pyroxene to produce a dense network of veins comprised of secondary minerals: Serpentine + brucite ± magnetite veins occur in olivine, Al-rich serpentine + talc veins occur in orthopyroxene, and Al-rich serpentine ± talc ± brucite veins occur at the boundary between orthopyroxene and olivine. Here, we present a detailed study on a harzburgite from the Santa Elena Ophiolite in Costa Rica that is ~30% serpentinized in order to provide new constraints on the effect of variable water (H2O) and silica (SiO2) activities on vein formation in peridotites. The studied sample records 1) mineralogical and chemical zonations in olivine-hosted veins that show a distinct pattern with increasing width of the veins (consumption of olivine), 2) varying brucite composition depending on whether or not it is associated with magnetite, and 3) chemical gradients in Si, Al, Cr, and Ca at the boundary between orthopyroxene- and olivine-hosted veins. These observed chemical variations suggest fluid mediated mass transport within and between orthopyroxene- and olivine-hosted veins. We use thermodynamic models to show that an increase in vein width and progressive evolution of olivine-hosted veins is accompanied by an increase in water-rock ratios. This is associated with the development of chemical gradients (e.g. gradients in water and silica activity) between the fluid-rich center of serpentine veins and the olivine grain boundaries as typically expressed by the abundance of brucite in the vein center and a dominance of serpentine at the boundary with olivine. The increase in water-rock ratios within the vein center also leads to the formation of magnetite from Fe-rich brucite ± Fe-rich serpentine. Mass transfer between vein core and vein rim may exist on the submicron-scale along grain boundaries of the finely intergrown serpentine-brucite mixture. We

  15. Gemini: A long-range cargo transport

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The proposed Gemini, a long-range cargo transport, is designed as a high capacity, dedicated cargo transporter of 8'x8'x20' inter-modal containers, and long-range design. These requirements will result in a design that is larger than any existing aircraft. Due to the size, a conventional configuration would result in an aircraft unable to operate economically at existing airports. It is necessary to design for a minimum possible empty weight, wingspan, and landing gear track. After considering both a single fuselage biplane and a double fuselage biplane configuration, the design team choose the double fuselage biplane configuration. Both of these configuration choices result in a reduced wing root bending moment and subsequently in substantial savings in the wing weight. An overall decrease in the weight of the airplane, its systems, and fuel will be a direct result of the wing weight savings.

  16. Holographic thermalization with initial long range correlation

    NASA Astrophysics Data System (ADS)

    Lin, Shu

    2016-01-01

    We studied the evolution of the Wightman correlator in a thermalizing state modeled by AdS3 -Vaidya background. We gave a prescription for calculating the Wightman correlator in coordinate space without using any approximation. For equal-time correlator ⟨ O (v ,x )O (v ,0 )⟩ , we obtained an enhancement factor v2 due to long range correlation present in the initial state. This was missed by previous studies based on geodesic approximation. We found that the long range correlation in initial state does not lead to significant modification to thermalization time as compared to known results with generic initial state. We also studied the spatially integrated Wightman correlator and showed evidence on the distinction between long distance and small momentum physics for an out-of-equilibrium state. We also calculated the radiation spectrum of particles weakly coupled to O and found that lower frequency mode approaches thermal spectrum faster than high frequency mode.

  17. Holographic thermalization with initial long range correlation

    DOE PAGESBeta

    Lin, Shu

    2016-01-19

    Here, we studied the evolution of the Wightman correlator in a thermalizing state modeled by AdS3-Vaidya background. A prescription was given for calculating the Wightman correlator in coordinate space without using any approximation. For equal-time correlator , we obtained an enhancement factor v2 due to long range correlation present in the initial state. This was missed by previous studies based on geodesic approximation. Moreover, we found that the long range correlation in initial state does not lead to significant modification to thermalization time as compared to known results with generic initial state. We also studied the spatially integrated Wightman correlatormore » and showed evidence on the distinction between long distance and small momentum physics for an out-of-equilibrium state. We also calculated the radiation spectrum of particles weakly coupled to O and found that lower frequency mode approaches thermal spectrum faster than high frequency mode.« less

  18. Critical Hamiltonians with long range hopping

    NASA Astrophysics Data System (ADS)

    Levitov, L. S.

    1999-11-01

    Critical states are studied by a real space RG in the problem with strong diagonal disorder and long range power law hopping. The RG ow of the distribution of coupling parameters is characterized by a family of non-trivial fix points. We consider the RG flow of the distribution of participation ratios of eigenstates. Scaling of participation ratios is sensitive to the nature of the RG fix point. For some fix points, scaling of participation ratios is characterized by a distribution of exponents, rather than by a single exponent.The RG method can be generalized to treat certain fermionic Hamiltonians with disorder and long range hopping. We derive the RG for a model of interacting two-level systems. Besides couplings, in this problem the RG includes the density of states. The density of states is renormalized so that it develops a singularity near zero energy.

  19. Long-range correlations in nucleotide sequences

    NASA Astrophysics Data System (ADS)

    Peng, C.-K.; Buldyrev, S. V.; Goldberger, A. L.; Havlin, S.; Sciortino, F.; Simons, M.; Stanley, H. E.

    1992-03-01

    DNA SEQUENCES have been analysed using models, such as an it-step Markov chain, that incorporate the possibility of short-range nucleotide correlations1. We propose here a method for studying the stochastic properties of nucleotide sequences by constructing a 1:1 map of the nucleotide sequence onto a walk, which we term a 'DNA walk'. We then use the mapping to provide a quantitative measure of the correlation between nucleotides over long distances along the DNA chain. Thus we uncover in the nucleotide sequence a remarkably long-range power law correlation that implies a new scale-invariant property of DNA. We find such long-range correlations in intron-containing genes and in nontranscribed regulatory DNA sequences, but not in complementary DNA sequences or intron-less genes.

  20. Long-range charge transfer in biopolymers

    NASA Astrophysics Data System (ADS)

    Astakhova, T. Yu; Likhachev, V. N.; Vinogradov, G. A.

    2012-11-01

    The results of theoretical and experimental studies on the charge transfer in biopolymers, namely, DNA and peptides, are presented. Conditions that ensure the efficient long-range charge transport (by several tens of nanometres) are considered. The known theoretical models of charge transfer mechanisms are discussed and the scopes of their application are analyzed. Attention is focused on the charge transport by the polaron mechanism. The bibliography includes 262 references.

  1. Long-range hybrid wedge plasmonic waveguide.

    PubMed

    Zhang, Zhonglai; Wang, Jian

    2014-01-01

    We design a novel long-range hybrid wedge plasmonic (LRHWP) waveguide composed of two identical dielectric nanowires symmetrically placed on two opposed wedges of a diamond shaped metal wire. With strong coupling between the dielectric nanowire mode and long-range surface plasmon polariton (SPP) mode, both deep subwavelength mode confinement and low propagation loss are achieved. On one hand, when compared to the previous long-range hybrid SPP waveguide, LRHWP waveguide can achieve smaller mode size with similar propagation length; on the other hand, when compared to the previous hybrid wedge SPP waveguide, LRHWP waveguide can provide an order of magnitude longer propagation length with similar level of mode confinement. The designed LRHWP waveguide also features an overall advantage of one-order improvement of Figure of Merit. We further evaluate in detail the impacts of possible practical fabrication imperfections on the mode properties. The obtained results of mode properties show that the proposed LRHWP waveguide with an optimized wedge tip angle of 140 degree is fairly tolerant to practical fabrication errors in geometry parameters such as misalignment in the horizontal direction, asymmetry in the vertical direction, variation of wedge tip angle, tilt or rotation of metal wire, and variation of wedge tip curvature radius. PMID:25362900

  2. Long-range hybrid wedge plasmonic waveguide

    PubMed Central

    Zhang, Zhonglai; Wang, Jian

    2014-01-01

    We design a novel long-range hybrid wedge plasmonic (LRHWP) waveguide composed of two identical dielectric nanowires symmetrically placed on two opposed wedges of a diamond shaped metal wire. With strong coupling between the dielectric nanowire mode and long-range surface plasmon polariton (SPP) mode, both deep subwavelength mode confinement and low propagation loss are achieved. On one hand, when compared to the previous long-range hybrid SPP waveguide, LRHWP waveguide can achieve smaller mode size with similar propagation length; on the other hand, when compared to the previous hybrid wedge SPP waveguide, LRHWP waveguide can provide an order of magnitude longer propagation length with similar level of mode confinement. The designed LRHWP waveguide also features an overall advantage of one-order improvement of Figure of Merit. We further evaluate in detail the impacts of possible practical fabrication imperfections on the mode properties. The obtained results of mode properties show that the proposed LRHWP waveguide with an optimized wedge tip angle of 140 degree is fairly tolerant to practical fabrication errors in geometry parameters such as misalignment in the horizontal direction, asymmetry in the vertical direction, variation of wedge tip angle, tilt or rotation of metal wire, and variation of wedge tip curvature radius. PMID:25362900

  3. Fabricating nanoscale chemical gradients with ThermoChemical NanoLithography.

    PubMed

    Carroll, Keith M; Giordano, Anthony J; Wang, Debin; Kodali, Vamsi K; Scrimgeour, Jan; King, William P; Marder, Seth R; Riedo, Elisa; Curtis, Jennifer E

    2013-07-01

    Production of chemical concentration gradients on the submicrometer scale remains a formidable challenge, despite the broad range of potential applications and their ubiquity throughout nature. We present a strategy to quantitatively prescribe spatial variations in functional group concentration using ThermoChemical NanoLithography (TCNL). The approach uses a heated cantilever to drive a localized nanoscale chemical reaction at an interface, where a reactant is transformed into a product. We show using friction force microscopy that localized gradients in the product concentration have a spatial resolution of ~20 nm where the entire concentration profile is confined to sub-180 nm. To gain quantitative control over the concentration, we introduce a chemical kinetics model of the thermally driven nanoreaction that shows excellent agreement with experiments. The comparison provides a calibration of the nonlinear dependence of product concentration versus temperature, which we use to design two-dimensional temperature maps encoding the prescription for linear and nonlinear gradients. The resultant chemical nanopatterns show high fidelity to the user-defined patterns, including the ability to realize complex chemical patterns with arbitrary variations in peak concentration with a spatial resolution of 180 nm or better. While this work focuses on producing chemical gradients of amine groups, other functionalities are a straightforward modification. We envision that using the basic scheme introduced here, quantitative TCNL will be capable of patterning gradients of other exploitable physical or chemical properties such as fluorescence in conjugated polymers and conductivity in graphene. The access to submicrometer chemical concentration and gradient patterning provides a new dimension of control for nanolithography. PMID:23751047

  4. Long-range imaging ladar flight test

    NASA Astrophysics Data System (ADS)

    Brandt, James; Steiner, Todd D.; Mandeville, William J.; Dinndorf, Kenneth M.; Krasutsky, Nick J.; Minor, John L.

    1995-06-01

    Wright Laboratory and Loral Vought Systems (LVS) have been involved for the last nine years in the research and development of high power diode pumped solid state lasers for medium to long range laser radar (LADAR) seekers for tactical air-to-ground munitions. LVS provided the lead in three key LADAR programs at Wright Lab; the Submunition Guidance Program (Subguide), the Low Cost Anti-Armor Submunition Program (LOCAAS) and the Diode Laser and Detector Array Development Program (3-D). This paper discusses recent advances through the 3-D program that provide the opportunity to obtain three dimensional laser radar imagery in captive flight at a range of 5 km.

  5. Fan-less long range alpha detector

    DOEpatents

    MacArthur, Duncan W.; Bounds, John A.

    1994-01-01

    A fan-less long range alpha detector which operates by using an electrical field between a signal plane and the surface or substance to be monitored for air ions created by collisions with alpha radiation. Without a fan, the detector can operate without the possibility of spreading dust and potential contamination into the atmosphere. A guard plane between the signal plane and the electrically conductive enclosure and maintained at the same voltage as the signal plane, reduces leakage currents. The detector can easily monitor soil, or other solid or liquid surfaces.

  6. Fan-less long range alpha detector

    DOEpatents

    MacArthur, D.W.; Bounds, J.A.

    1994-05-10

    A fan-less long range alpha detector is disclosed which operates by using an electrical field between a signal plane and the surface or substance to be monitored for air ions created by collisions with alpha radiation. Without a fan, the detector can operate without the possibility of spreading dust and potential contamination into the atmosphere. A guard plane between the signal plane and the electrically conductive enclosure and maintained at the same voltage as the signal plane, reduces leakage currents. The detector can easily monitor soil, or other solid or liquid surfaces. 2 figures.

  7. A criterion autoscheduler for long range planning

    NASA Technical Reports Server (NTRS)

    Sponsler, Jeffrey L.

    1994-01-01

    A constraint-based scheduling system called SPIKE is used to create long-term schedules for the Hubble Space Telescope. A meta-level scheduler called the Criterion Autoscheduler for Long range planning (CASL) was created to guide SPIKE's schedule generation according to the agenda of the planning scientists. It is proposed that sufficient flexibility exists in a schedule to allow high level planning heuristics to be applied without adversely affected crucial constraints such as spacecraft efficiency. This hypothesis is supported by test data which is described.

  8. NASA's Long-range Technology Goals

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This document is part of the Final Report performed under contract NASW-3864, titled "NASA's Long-Range Technology Goals". The objectives of the effort were: To identify technologies whose development falls within NASA's capability and purview, and which have high potential for leapfrog advances in the national industrial posture in the 2005-2010 era. To define which of these technologies can also enable quantum jumps in the national space program. To assess mechanisms of interaction between NASA and industry constituencies for realizing the leapfrog technologies. This Volume details the findings pertaining to the advanced space-enabling technologies.

  9. Long-range polarimetric imaging through fog.

    PubMed

    Fade, Julien; Panigrahi, Swapnesh; Carré, Anthony; Frein, Ludovic; Hamel, Cyril; Bretenaker, Fabien; Ramachandran, Hema; Alouini, Mehdi

    2014-06-20

    We report an experimental implementation of long-range polarimetric imaging through fog over kilometric distance in real field atmospheric conditions. An incoherent polarized light source settled on a telecommunication tower is imaged at a distance of 1.3 km with a snapshot polarimetric camera including a birefringent Wollaston prism, allowing simultaneous acquisition of two images along orthogonal polarization directions. From a large number of acquisitions datasets and under various environmental conditions (clear sky/fog/haze, day/night), we compare the efficiency of using polarized light for source contrast increase with different signal representations (intensity, polarimetric difference, polarimetric contrast, etc.). With the limited-dynamics detector used, a maximum fourfold increase in contrast was demonstrated under bright background illumination using polarimetric difference image. PMID:24979415

  10. Fe-based long range ordered alloys

    DOEpatents

    Liu, C.T.

    Malleable long range ordered alloys with high critical ordering temperatures exist in the V(Co,Fe)/sub 3/ and V(Co,Fe,Ni)/sub 3/ system. The composition comprising by weight 22 to 23% V, 35 to 50% Fe, 0 to 22% Co and 19 to 40% Ni with an electron density no greater than 8.00. Excellent high temperature properties occur in alloys having compositions comprising by weight 22 to 23% V, 35 to 45% Fe, 0 to 10% Co, 25 to 35% Ni; 22 to 23% V, 28 to 33% Ni and the remainder Fe; and 22 to 23% V, 19 to 22% Co and the remainder Fe. The alloys are fabricable by casting, deforming and annealing for sufficient time to provide ordered structure.

  11. Fe-based long range ordered alloys

    DOEpatents

    Liu, Chain T; Inouye, Henry; Schaffhauser, Anthony C.

    1980-01-01

    Malleable long range ordered alloys having high critical ordering temperatures exist in the V(Co,Fe).sub.3 and V(Co,Fe,Ni).sub.3 system having the composition comprising by weight 22-23% V, 35-50% Fe, 0-22% Co and 19-40% Ni with an electron density no greater than 8.00. Excellent high temperature properties occur in alloys having compositions comprising by weight 22-23% V, 35-45% Fe, 0-10% Co, 25-35% Ni; 22-23% V, 28-33% Ni and the remainder Fe; and 22-23% V, 19-22% Ni, 19-22% Co and the remainder Fe. The alloys are fabricable by casting, deforming and annealing for sufficient time to provide ordered structure.

  12. A Long-Range Video Observation Post

    SciTech Connect

    Arlowe, D.

    1995-07-01

    The Long Range Video Observation Post (LRVOP) Project is a cooperative effort between the US and a Middle Eastern country to develop an improved version of their current video observation post. This project is part of a larger effort to cooperatively develop anti-terrorist technology. This particular equipment is required to facilitate the recording and identification of humans at a range of 1000 meters in day-light and 500 meters at night. The project objective was to take advantage of recent advances in camera technology, recorders, and image processing to provide an significant increase in performance with only a minimum increase in size, weight, and cost. The goal of the project was to convert the users general needs and desires into specific requirements that could be bid on by several companies. This paper covers the specific performance requirements, generally describe the components that might be used, and concentrate on describing the more difficult issues and technical challenges.

  13. Long-range interaction of anisotropic systems

    NASA Astrophysics Data System (ADS)

    Zhang, J.-Y.; Schwingenschlögl, U.

    2015-02-01

    The first-order electrostatic interaction energy between two far-apart anisotropic atoms depends not only on the distance between them but also on their relative orientation, according to Rayleigh-Schrödinger perturbation theory. Using the first-order interaction energy and the continuum model, we study the long-range interaction between a pair of parallel pristine graphene sheets at zero temperature. The asymptotic form of the obtained potential density, \\varepsilon(D) \\propto -D-3-O(D-4) , is consistent with the random phase approximation and Lifshitz theory. Accordingly, neglectance of the anisotropy, especially the nonzero first-order interaction energy, is the reason why the widely used Lennard-Jones potential approach and dispersion corrections in density functional theory give a wrong asymptotic form \\varepsilon(D) \\propto -D-4 .

  14. Long range inductive power transfer system

    NASA Astrophysics Data System (ADS)

    Lawson, James; Pinuela, Manuel; Yates, David C.; Lucyszyn, Stepan; Mitcheson, Paul D.

    2013-12-01

    We report upon a recently developed long range inductive power transfer system (IPT) designed to power remote sensors with mW level power consumption at distances up to 7 m. In this paper an inductive link is established between a large planar (1 × 1 m) transmit coil (Tx) and a small planer (170 × 170 mm) receiver coil (Rx), demonstrating the viability of highly asymmetrical coil configurations that real-world applications such as sensor networks impose. High Q factor Tx and Rx coils required for viable power transfer efficiencies over such distances are measured using a resonant method. The applicability of the Class-E amplifier in very low magnetic coupling scenarios and at the high frequencies of operation required for high Q operation is demonstrated by its usage as the Tx coil driver.

  15. Long range position and Orientation Tracking System

    SciTech Connect

    Armstrong, G.A.; Jansen, J.F.; Burks, B.L.

    1996-02-01

    The long range Position and Orientation Tracking System is an active triangulation-based system that is being developed to track a target to a resolution of 6.35 mm (0.25 in.) and 0.009{degrees}(32.4 arcseconds) over a range of 13.72 m (45 ft.). The system update rate is currently set at 20 Hz but can be increased to 100 Hz or more. The tracking is accomplished by sweeping two pairs of orthogonal line lasers over infrared (IR) sensors spaced with known geometry with respect to one another on the target (the target being a rigid body attached to either a remote vehicle or a remote manipulator arm). The synchronization and data acquisition electronics correlates the time that an IR sensor has been hit by one of the four lasers and the angle of the respective mirror at the time of the hit. This information is combined with the known geometry of the IR sensors on the target to determine position and orientation of the target. This method has the advantage of allowing the target to be momentarily lost due to occlusions and then reacquired without having to return the target to a known reference point. The system also contains a camera with operator controlled lighting in each pod that allows the target to be continuously viewed from either pod, assuming their are no occlusions.

  16. Long-range forecasting of intermittent streamflow

    NASA Astrophysics Data System (ADS)

    van Ogtrop, F. F.; Vervoort, R. W.; Heller, G. Z.; Stasinopoulos, D. M.; Rigby, R. A.

    2011-01-01

    Long-range forecasting of intermittent streamflow in semi-arid Australia poses a number of major challenges. One of the challenges relates to modelling zero, skewed, non-stationary, and non-linear data. To address this, a probabilistic statistical model to forecast streamflow 12 months ahead is applied to five semi-arid catchments in South Western Queensland. The model uses logistic regression through Generalised Additive Models for Location, Scale and Shape (GAMLSS) to determine the probability of flow occurring in any of the systems. We then use the same regression framework in combination with a right-skewed distribution, the Box-Cox t distribution, to model the intensity (depth) of the non-zero streamflows. Time, seasonality and climate indices, describing the Pacific and Indian Ocean sea surface temperatures, are tested as covariates in the GAMLSS model to make probabilistic 12-month forecasts of the occurrence and intensity of streamflow. The output reveals that in the study region the occurrence and variability of flow is driven by sea surface temperatures and therefore forecasts can be made with some skill.

  17. Long-range forecasting of intermittent streamflow

    NASA Astrophysics Data System (ADS)

    van Ogtrop, F. F.; Vervoort, R. W.; Heller, G. Z.; Stasinopoulos, D. M.; Rigby, R. A.

    2011-11-01

    Long-range forecasting of intermittent streamflow in semi-arid Australia poses a number of major challenges. One of the challenges relates to modelling zero, skewed, non-stationary, and non-linear data. To address this, a statistical model to forecast streamflow up to 12 months ahead is applied to five semi-arid catchments in South Western Queensland. The model uses logistic regression through Generalised Additive Models for Location, Scale and Shape (GAMLSS) to determine the probability of flow occurring in any of the systems. We then use the same regression framework in combination with a right-skewed distribution, the Box-Cox t distribution, to model the intensity (depth) of the non-zero streamflows. Time, seasonality and climate indices, describing the Pacific and Indian Ocean sea surface temperatures, are tested as covariates in the GAMLSS model to make probabilistic 6 and 12-month forecasts of the occurrence and intensity of streamflow. The output reveals that in the study region the occurrence and variability of flow is driven by sea surface temperatures and therefore forecasts can be made with some skill.

  18. Long range position and orientation tracking system

    SciTech Connect

    Armstrong, G.A.; Jansen, J.F.; Burks, B.L.; Bernacki, B.E.; Nypaver, D.J.

    1995-12-31

    The long range position and orientation tracking system (LRPOTS) will consist of two measurement pods, a VME-based computer system, and a detector array. The system is used to measure the position and orientation of a target that may be attached to a robotic arm, teleoperated manipulator, or autonomous vehicle. The pods have been designed to be mounted in the man-ways of the domes of the Fernald K-65 waste silos. Each pod has two laser scanner subsystems as well as lights and camera systems. One of the laser scanners will be oriented to scan in the pan direction, the other in the tilt direction. As the lasers scan across the detector array, the angles of incidence with each detector are recorded. Combining measurements from each of the four lasers yields sufficient data for a closed-form solution of the transform describing the location and orientation of the Content Mobilization System (CMS). Redundant detectors will be placed on the CMS to accommodate occlusions, to provide improved measurement accuracy, and to determine the CMS orientation.

  19. A long-range laser velocimeter

    NASA Technical Reports Server (NTRS)

    Reinath, Michael S.

    1991-01-01

    A long-range laser velocimeter (LV) developed for remote operation from within the flow fields of large wind tunnels is described. Emphasis is placed on recent improvements in optical hardware as well as recent additions to data acquisition and processing techniques. The method used for data reduction of photon resolved signals is outlined in detail, and measurement accuracy is discussed. To study the performance of the LV and verify the measurement accuracy, laboratory measurements were made in the flow field of a 10-cm-diameter, 30-m/s axisymetric jet. The measured velocity and turbulence intensity surveys are compared with measurements made with a hot-wire anemometer. Additionally, the LV was used during the flow calibration of the 80-ft x 120-ft wind tunnel to measure the test-section boundary-layer thickness at the maximum wind tunnel speed of 51.5 m/s. The requirements and techniques used to seed the flow are discussed, and boundary-layer surveys of mean velocity and turbulence intensity of the streamwise component and the component normal to the surface are presented. The streamwise component of mean velocity is compared with data obtained with a total pressure rake.

  20. Dynamic designing of microstructures by chemical gradient-mediated growth

    PubMed Central

    Shim, Tae Soup; Yang, Seung-Man; Kim, Shin-Hyun

    2015-01-01

    Shape is one of the most important determinants of the properties of microstructures. Despite of a recent progress on microfabrication techniques, production of three-dimensional micro-objects are yet to be fully achieved. Nature uses reaction–diffusion process during bottom-up self-assembly to create functional shapes and patterns with high complexity. Here we report a method to produce polymeric microstructures by using a dynamic reaction–diffusion process during top-down photolithography, providing unprecedented control over shape and composition. In radical polymerization, oxygen inhibits reaction, and therefore diffusion of oxygen significantly alters spatial distribution of growth rate. Therefore, growth pathways of the microstructures can be controlled by engineering a concentration gradient of oxygen. Moreover, stepwise control of chemical gradients enables the creation of highly complex microstructures. The ease of use and high controllability of this technology provide new opportunities for microfabrication and for fundamental studies on the relationships between shape and function for the materials. PMID:25766762

  1. Accurate ab initio energy gradients in chemical compound space.

    PubMed

    Anatole von Lilienfeld, O

    2009-10-28

    Analytical potential energy derivatives, based on the Hellmann-Feynman theorem, are presented for any pair of isoelectronic compounds. Since energies are not necessarily monotonic functions between compounds, these derivatives can fail to predict the right trends of the effect of alchemical mutation. However, quantitative estimates without additional self-consistency calculations can be made when the Hellmann-Feynman derivative is multiplied with a linearization coefficient that is obtained from a reference pair of compounds. These results suggest that accurate predictions can be made regarding any molecule's energetic properties as long as energies and gradients of three other molecules have been provided. The linearization coefficent can be interpreted as a quantitative measure of chemical similarity. Presented numerical evidence includes predictions of electronic eigenvalues of saturated and aromatic molecular hydrocarbons. PMID:19894922

  2. First hyperpolarizability of polymethineimine with long-range corrected functionals

    NASA Astrophysics Data System (ADS)

    Jacquemin, Denis; Perpète, Eric A.; Medved', Miroslav; Scalmani, Giovanni; Frisch, Michael J.; Kobayashi, Rika; Adamo, Carlo

    2007-05-01

    Using the long-range corrected (LC) density functional theory (DFT) scheme introduced by Iikura et al. [J. Chem. Phys. 115, 3540 (2001)] and the Coulomb-attenuating model (CAM-B3LYP) of Yanai et al. [Chem. Phys. Lett. 393, 51 (2004)], we have calculated the longitudinal dipole moments and static electronic first hyperpolarizabilities of increasingly long polymehtineimine oligomers. For comparison purposes Hartree-Fock (HF), Møller-Plesset perturbation theory (MP2), and conventional pure and hybrid functionals have been considered as well. HF, generalized gradient approximation (GGA), and conventional hybrids provide too large dipole moments for long oligomers, while LC-DFT allows to reduce the discrepancy with respect to MP2 by a factor of 3. For the first hyperpolarizability, the incorrect evolution with the chain length predicted by HF is strongly worsened by BLYP, Perdew-Burke-Ernzerhof (PBE), and also by B3LYP and PBE0. On the reverse, LC-BLYP and LC-PBE hyperpolarizabilities are correctly predicted to be positive (but for the two smallest chains). Indeed, for medium and long oligomers LC hyperpolarizabilities are slightly smaller than MP2 hyperpolarizabilities, as it should be. CAM-B3LYP also strongly improves the B3LYP results, though a bit less impressively for small chain lengths. The present study demonstrates the efficiency of long-range DFT, even in very pathological cases.

  3. Long-range dismount activity classification: LODAC

    NASA Astrophysics Data System (ADS)

    Garagic, Denis; Peskoe, Jacob; Liu, Fang; Cuevas, Manuel; Freeman, Andrew M.; Rhodes, Bradley J.

    2014-06-01

    Continuous classification of dismount types (including gender, age, ethnicity) and their activities (such as walking, running) evolving over space and time is challenging. Limited sensor resolution (often exacerbated as a function of platform standoff distance) and clutter from shadows in dense target environments, unfavorable environmental conditions, and the normal properties of real data all contribute to the challenge. The unique and innovative aspect of our approach is a synthesis of multimodal signal processing with incremental non-parametric, hierarchical Bayesian machine learning methods to create a new kind of target classification architecture. This architecture is designed from the ground up to optimally exploit correlations among the multiple sensing modalities (multimodal data fusion) and rapidly and continuously learns (online self-tuning) patterns of distinct classes of dismounts given little a priori information. This increases classification performance in the presence of challenges posed by anti-access/area denial (A2/AD) sensing. To fuse multimodal features, Long-range Dismount Activity Classification (LODAC) develops a novel statistical information theoretic approach for multimodal data fusion that jointly models multimodal data (i.e., a probabilistic model for cross-modal signal generation) and discovers the critical cross-modal correlations by identifying components (features) with maximal mutual information (MI) which is efficiently estimated using non-parametric entropy models. LODAC develops a generic probabilistic pattern learning and classification framework based on a new class of hierarchical Bayesian learning algorithms for efficiently discovering recurring patterns (classes of dismounts) in multiple simultaneous time series (sensor modalities) at multiple levels of feature granularity.

  4. Mechanism of long-range proton translocation along biological membranes

    PubMed Central

    Medvedev, Emile S.; Stuchebrukhov, Alexei A.

    2014-01-01

    Recent experiments suggest that protons can travel along biological membranes up to tens of micrometers, but the mechanism of transport is unknown. To explain such a long-range proton translocation we describe a model that takes into account the coupled bulk diffusion that accompanies the migration of protons on the surface. We show that protons diffusing at or near the surface before equilibrating with the bulk desorb and re-adsorb at the surface thousands of times, giving rise to a power-law desorption kinetics. As a result, the decay of the surface protons occurs very slowly, allowing for establishing local gradient and local exchange, as was envisioned in the early local models of biological energy transduction. PMID:23268201

  5. Long range migration of aphids into Sweden

    NASA Astrophysics Data System (ADS)

    Wiktelius, Staffan

    1984-09-01

    A five year study of migration of aphids across the southern part of the Baltic Sea is reported. The aphids were caught in a suction trap placed on a lighthouse 50 m from the shoreline. Large sections of the results are presented as case studies i.e. catches of aphids from periods containing at least three consecutive days with a southerly gradient wind. Some periods contained large and diverse catches and it is assumed that aphids regularly cross the Baltic Sea. The catches was largest on days when a cold front passed the trapping site within a period. More Myzus persicae were caught on days when the wind was southerly than on days with a northerly wind direction.

  6. Nonlinear Behaviour in Long Range Integrable Models with Spin

    NASA Astrophysics Data System (ADS)

    Kulkarni, Manas; Franchini, Fabio; Abanov, Alexander

    2010-03-01

    We study nonlinear aspects of long range integrable models with spin by going beyond the Luttinger Liquid theory. We present here [1], the fully nonlinear dynamics of spin and charge in spin-Calogero model (sCM), an integrable 1D model of quantum spin-1/2 particles interacting through inverse square interaction and exchange. Hydrodynamic equations of motion are written for this model in the regime where gradient corrections to the exact theory may be neglected. In this approximation, variables separate in terms of dressed Fermi momenta of the model. Hydrodynamic equations reduce to a set of decoupled Riemann-Hopf equations for the dressed Fermi momenta. We study the dynamics of some non-equilibrium spin-charge configurations for times smaller than the time-scale of gradient catastrophe. We then show [2] how this field theory allows to calculate correlation functions that cannot be considered with conventional bosonization. We also highlight the connections between sCM, Haldane-Shastry model and λ=2 spin-less Calogero model. [1] M. Kulkarni, F. Franchini, A. G. Abanov, Phys. Rev. B 80, 165105 (2009) [2] F. Franchini, M. Kulkarni, Nucl. Phys. B, 825, 320 (2010)

  7. Functional Sites Induce Long-Range Evolutionary Constraints in Enzymes

    PubMed Central

    Jack, Benjamin R.; Meyer, Austin G.; Echave, Julian; Wilke, Claus O.

    2016-01-01

    Functional residues in proteins tend to be highly conserved over evolutionary time. However, to what extent functional sites impose evolutionary constraints on nearby or even more distant residues is not known. Here, we report pervasive conservation gradients toward catalytic residues in a dataset of 524 distinct enzymes: evolutionary conservation decreases approximately linearly with increasing distance to the nearest catalytic residue in the protein structure. This trend encompasses, on average, 80% of the residues in any enzyme, and it is independent of known structural constraints on protein evolution such as residue packing or solvent accessibility. Further, the trend exists in both monomeric and multimeric enzymes and irrespective of enzyme size and/or location of the active site in the enzyme structure. By contrast, sites in protein–protein interfaces, unlike catalytic residues, are only weakly conserved and induce only minor rate gradients. In aggregate, these observations show that functional sites, and in particular catalytic residues, induce long-range evolutionary constraints in enzymes. PMID:27138088

  8. A natural orbital analysis of the long range behavior of chemical bonding and van der Waals interaction in singlet H2: the issue of zero natural orbital occupation numbers.

    PubMed

    Sheng, X W; Mentel, Ł M; Gritsenko, O V; Baerends, E J

    2013-04-28

    This paper gives a natural orbital (NO) based analysis of the van der Waals interaction in (singlet) H2 at long distance. The van der Waals interaction, even if not leading to a distinct van der Waals well, affects the shape of the interaction potential in the van der Waals distance range of 5-9 bohrs and can be clearly distinguished from chemical bonding effects. In the NO basis the van der Waals interaction can be quantitatively covered with, apart from the ground state configurations (1σ(g))(2) and (1σ(u))(2), just the 4 configurations (2σ(g))(2) and (2σ(u))(2), and (1π(u))(2) and (1π(g))(2). The physics of the dispersion interaction requires and explains the peculiar relatively large positive CI coefficients of the doubly excited electron configurations (2σ(u))(2) and (1π(g))(2) (the occupancy amplitudes of the 2σ(u) and 1π(gx, y) NOs) in the distance range 5-9 bohrs, which have been observed before by Cioslowski and Pernal [Chem. Phys. Lett. 430, 188 (2006)]. We show that such positive occupancy amplitudes do not necessarily lead to the existence of zero occupation numbers at some H-H distances. PMID:23635109

  9. Modeling of forced flow/thermal gradient chemical vapor infiltration

    SciTech Connect

    Starr, T.L.; Smith, A.W.

    1992-09-01

    The forced flow/thermal gradient chemical vapor infiltration process (FCVI) has proven to be a successful technique for fabrication of ceramic matrix composites. It is particularly attractive for thick components which cannot be fabricated using the conventional, isothermal method (ICVI). Although it offers processing times that are at least an order of magnitude shorter than ICVI, FCVI has not been used to fabricate parts of complex geometry and is perceived by some to be unsuitable for such components. The major concern Is that selection and control of the flow pattern and thermal profile for optimum infiltration can be a difficult and costly exercise. In order to reduce this effort, we are developing a computer model for FCVI that simulates the densification process for given component geometry, reactor configuration and operating parameters. Used by a process engineer, this model can dramatically reduce the experimental effort needed to obtain uniform densification. A one-dimensional process model, described in a previous interim report, has demonstrated good agreement with experimental results in predicting overall densification time and density uniformity during processing and the effect of various fiber architectures and operating parameters on these process issues. This model is fundamentally unsuitable for more complex geometries, however, and extension to two- and three-dimensions is necessary. This interim report summarizes our progress since the previous interim report toward development of a ``finite volume`` model for FCVI.

  10. Modeling of forced flow/thermal gradient chemical vapor infiltration

    SciTech Connect

    Starr, T.L.; Smith, A.W. )

    1992-09-01

    The forced flow/thermal gradient chemical vapor infiltration process (FCVI) has proven to be a successful technique for fabrication of ceramic matrix composites. It is particularly attractive for thick components which cannot be fabricated using the conventional, isothermal method (ICVI). Although it offers processing times that are at least an order of magnitude shorter than ICVI, FCVI has not been used to fabricate parts of complex geometry and is perceived by some to be unsuitable for such components. The major concern Is that selection and control of the flow pattern and thermal profile for optimum infiltration can be a difficult and costly exercise. In order to reduce this effort, we are developing a computer model for FCVI that simulates the densification process for given component geometry, reactor configuration and operating parameters. Used by a process engineer, this model can dramatically reduce the experimental effort needed to obtain uniform densification. A one-dimensional process model, described in a previous interim report, has demonstrated good agreement with experimental results in predicting overall densification time and density uniformity during processing and the effect of various fiber architectures and operating parameters on these process issues. This model is fundamentally unsuitable for more complex geometries, however, and extension to two- and three-dimensions is necessary. This interim report summarizes our progress since the previous interim report toward development of a finite volume'' model for FCVI.

  11. Emergent long-range magnetic ordering in manganite superlattices

    NASA Astrophysics Data System (ADS)

    Burganov, Bulat; Macke, Sebastian; Monkman, Eric; Adamo, Carolina; Shai, Daniel; Schlom, Darrell; Sawatzky, George; Shen, Kyle

    2015-03-01

    Complex oxides composed into atomically precise heterostructures host a plethora of new phenomena driven by interface effects, dimensionality, correlations and strain. An example is emergent ferromagnetism in the superlattices (SL) of LaMnO3/SrMnO3 and the dimensionality-driven metal insulator transition, still not well understood theoretically. We use soft x-ray scattering combined with SQUID magnetometry to determine the magnetic and orbital ordering in the (LaMnO3)2n /(SrMnO3)n SL for n =1,2,3,4. By composition this system is close to colossal-magnetoresistive La2/3Sr1/3MnO3, an FM metal below 400K. The system undergoes a metal-insulator transition with higher n and is believed to have a complex magnetic ordering. We observe an unexpected long-range order in the n =4 sample where the magnetic period is equal to two chemical periods. The observed half-order Bragg peaks show strong linear and no circular dichroism. The temperature and polarization dependence of reflectometry points towards alignment between A-type AFM orders in the neighboring LaMnO3 layers, which is very unusual and indicates a long range interaction acting across the thick SrMnO3 layers with nominally G-type spin configuration. We simulate the reflectometry data for several model spin configurations to further elucidate the nature of this ordering.

  12. DNA Structural Correlation in Short and Long Ranges.

    PubMed

    Gu, Chan; Zhang, Jun; Yang, Y Isaac; Chen, Xi; Ge, Hao; Sun, Yujie; Su, Xiaodong; Yang, Lijiang; Xie, Sunney; Gao, Yi Qin

    2015-11-01

    Recent single-molecule measurements have revealed the DNA allostery in protein/DNA binding. MD simulations showed that this allosteric effect is associated with the deformation properties of DNA. In this study, we used MD simulations to further investigate the mechanism of DNA structural correlation, its dependence on DNA sequence, and the chemical modification of the bases. Besides a random sequence, poly d(AT) and poly d(GC) are also used as simpler model systems, which show the different bending and twisting flexibilities. The base-stacking interactions and the methyl group on the 5-carbon site of thymine causes local structures and flexibility to be very different for the two model systems, which further lead to obviously different tendencies of the conformational deformations, including the long-range allosteric effects. PMID:26439165

  13. Theory of Long-Range Ultracold Atom-Molecule Photoassociation

    NASA Astrophysics Data System (ADS)

    Pérez-Ríos, Jesús; Lepers, Maxence; Dulieu, Olivier

    2015-08-01

    The creation of ultracold molecules is currently limited to diatomic species. In this Letter, we present a theoretical description of the photoassociation of ultracold atoms and molecules to create ultracold excited triatomic molecules, thus being a novel example of a light-assisted ultracold chemical reaction. The calculation of the photoassociation rate of an ultracold Cs2 molecule in its rovibrational ground state with an ultracold Cs atom at frequencies close to its resonant excitation is reported, based on the solution of the quantum dynamics involving the atom-molecule long-range interactions and assuming a model potential for the short-range physics. The rate for the formation of excited Cs3 molecules is predicted to be comparable with currently observed atom-atom photoassociation rates. We formulate an experimental proposal to observe this process relying on the available techniques of optical lattices and standard photoassociation spectroscopy.

  14. Fieldwide Chemical and Isotopic Gradients in Steam from the Geysers

    SciTech Connect

    Truesdell, A.H.; Haizlip, J.R.; Box, W.T. Jr.; D'Amore, F.

    1987-01-20

    Strong fieldwide gradients from southeast to northwest in gas/steam and {delta}{sup 18}O have been found in steam produced from wells at The Geysers. These gradients result from recharge from the southeast that has increased liquid saturation in the southern part of the reservoir and flushed gases and high {delta}{sup 18}O connate waters to the north and out of the system through surface vents. Variations in the steepness of the gradients are probably related to major venting in the Big Geysers area. Although lateral steam flow and condensation subsequent to flushing explain some local gradients in the southern area, these processes cannot explain the fieldwide variations. 1 tab., 24 refs., 5 figs.

  15. A spatiotemporally controllable chemical gradient generator via acoustically oscillating sharp-edge structures.

    PubMed

    Huang, Po-Hsun; Chan, Chung Yu; Li, Peng; Nama, Nitesh; Xie, Yuliang; Wei, Cheng-Hsin; Chen, Yuchao; Ahmed, Daniel; Huang, Tony Jun

    2015-11-01

    The ability to generate stable, spatiotemporally controllable concentration gradients is critical for resolving the dynamics of cellular response to a chemical microenvironment. Here we demonstrate an acoustofluidic gradient generator based on acoustically oscillating sharp-edge structures, which facilitates in a step-wise fashion the rapid mixing of fluids to generate tunable, dynamic chemical gradients. By controlling the driving voltage of a piezoelectric transducer, we demonstrated that the chemical gradient profiles can be conveniently altered (spatially controllable). By adjusting the actuation time of the piezoelectric transducer, moreover, we generated pulsatile chemical gradients (temporally controllable). With these two characteristics combined, we have developed a spatiotemporally controllable gradient generator. The applicability and biocompatibility of our acoustofluidic gradient generator are validated by demonstrating the migration of human dermal microvascular endothelial cells (HMVEC-d) in response to a generated vascular endothelial growth factor (VEGF) gradient, and by preserving the viability of HMVEC-d cells after long-term exposure to an acoustic field. Our device features advantages such as simple fabrication and operation, compact and biocompatible device, and generation of spatiotemporally tunable gradients. PMID:26338516

  16. Chemical Gradient-mediated Melting Curve Analysis for Genotyping of Single Nucleotide Polymorphisms

    PubMed Central

    Russom, Aman; Irimia, Daniel; Toner, Mehmet

    2009-01-01

    This report describes a microfluidic solid-phase Chemical Gradient-mediated Melting Curve Analysis (CGMCA) method for single nucleotide polymorphism (SNP) analysis. The method is based on allele-specific denaturation to discriminate mismatched (MM) from perfectly matched (PM) DNA duplexes upon exposure to linear chemical gradient. PM and MM DNA duplexes conjugated on beads are captured in a microfluidic gradient generator device designed with dams, keeping the beads trapped perpendicular to a gradient generating channel. Two denaturants, formamide and urea, were tested for their ability to destabilize the DNA duplex by competing with Watson-Crick pairing. Upon exposure to the chemical gradient, rapid denaturing profile was monitored in real time using fluorescence microscopy. The results show that the two duplexes exhibit different kinetics of denaturation profiles, enabling discrimination of MM from PM DNA duplexes to score SNP. PMID:19593749

  17. Long Range Plan, 1993-1996. Pennsylvania College of Technology.

    ERIC Educational Resources Information Center

    Slotnick, Sandra; And Others

    At Pennsylvania College of Technology (PCT), in Williamsport, long range planning is used to define institutional philosophy and mission and determine strategies to make the best use of available resources and implement actions to fulfill institutional mission. This document presents PCT's long-range plan for 1993-96 in three parts. Following an…

  18. 77 FR 13683 - Alaska Federal Lands Long Range Transportation Plan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ... Federal Highway Administration Alaska Federal Lands Long Range Transportation Plan AGENCY: Federal Highway..., announced the availability of the draft Alaska Federal Lands Long Range Transportation Plans (LRTP) for..., 2011, at 76 FR 77300, the FHWA published a notice in the Federal Register inviting comments to...

  19. 76 FR 77300 - Alaska Federal Lands Long Range Transportation Plan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-12

    ... Federal Highway Administration Alaska Federal Lands Long Range Transportation Plan AGENCY: Federal Highway... Lands Long Range Transportation Plans (LRTP) for public review and comment. The draft plans outline a... United States Code Section 204 requires all Federal land management agencies to conduct long...

  20. Long-Range Planning and the Enrollment Decline.

    ERIC Educational Resources Information Center

    Fredrickson, John H.

    The current period of enrollment decline offers school districts an ideal opportunity for program and facility reevaluation and long-range planning. Any long-range plan should evaluate current programs in light of statutory and educational trends, estimate existing facilities' ability to accommodate change, determine the community's potential…

  1. A Model for Long Range Planning for Seminole Community College.

    ERIC Educational Resources Information Center

    Miner, Norris

    A model for long-range planning designed to maximize involvement of college personnel, to improve communication among various areas of the college, to provide a process for evaluation of long-range plans and the planning process, to adjust to changing conditions, to utilize data developed at a level useful for actual operations, and to have…

  2. Report of the Long-Range Planning Committee

    SciTech Connect

    Not Available

    1984-07-01

    This is the final report of the Long-Range Planning Committee of the Lawrence Livermore National Laboratory. It describes the make-up, purpose, working assumptions, and activities of the Committee and discusses the work done by the Committee on defense matters, energy, a number of additional topics, and future long-range planning activities.

  3. Quench dynamics in long-range interacting quantum systems

    NASA Astrophysics Data System (ADS)

    Gong, Zhexuan

    2016-05-01

    A distinctive feature of atomic, molecular, and optical systems is that interactions between particles are often long-ranged. Control techniques from quantum optics often allow one to tune the pattern of these long-range interactions, creating an entirely new degree of freedom, absent in typical condensed matter systems. These tunable long-range interactions can result in very different far-from-equilibrium dynamics compared to systems with only short-range interactions. In the first half of the talk, I will describe how very general types of long-range interactions can qualitatively change the entanglement and correlation growth shortly after a quantum quench. In the second half of the talk I will show that, at longer times, long-range interactions can lead to exotic quasi-stationary states and dynamical phase transitions. These theoretical ideas have been explored in recent trapped-ion experiments, and connections to these experiments will be emphasized in both parts of the talk.

  4. Truncated Long-Range Percolation on Oriented Graphs

    NASA Astrophysics Data System (ADS)

    van Enter, A. C. D.; de Lima, B. N. B.; Valesin, D.

    2016-07-01

    We consider different problems within the general theme of long-range percolation on oriented graphs. Our aim is to settle the so-called truncation question, described as follows. We are given probabilities that certain long-range oriented bonds are open; assuming that the sum of these probabilities is infinite, we ask if the probability of percolation is positive when we truncate the graph, disallowing bonds of range above a possibly large but finite threshold. We give some conditions in which the answer is affirmative. We also translate some of our results on oriented percolation to the context of a long-range contact process.

  5. Hyperfine-structure-induced purely long-range molecules.

    PubMed

    Enomoto, Katsunari; Kitagawa, Masaaki; Tojo, Satoshi; Takahashi, Yoshiro

    2008-03-28

    We have experimentally observed and theoretically identified a novel class of purely long-range molecules. This novel purely long-range state is formed due to a very weak hyperfine interaction that is usually treated only as a small perturbation in molecular spectra. Photoassociation spectroscopy of ultracold ytterbium (171Yb) atoms with the 1S0-3P1 intercombination transition presents clear identification of molecular states and the shallowest molecular potential depth of about 750 MHz among the purely long-range molecules ever observed. PMID:18517858

  6. Orthogonal, three-component, alkanethiol-based surface-chemical gradients on gold.

    PubMed

    Beurer, Eva; Venkataraman, Nagaiyanallur V; Rossi, Antonella; Bachmann, Florian; Engeli, Roman; Spencer, Nicholas D

    2010-06-01

    An orthogonal surface-chemical gradient composed of self-assembled monolayers on gold has been prepared by successive, controlled immersions in orthogonal directions into dilute solutions of dodecanethiol and perfluorododecanethiol. The resulting two-component orthogonal gradient in surface coverage was backfilled with 11-mercaptoundecanol, leading to a two-directional, three-component surface-chemical gradient. Water and hexadecane show distinctly different wetting behaviors on the gradient surface because of the differences in the hydrophobic and oleophobic natures of the three different constituents. These results are correlated with the chemical composition maps of the surface obtained by X-ray photoelectron spectroscopy. The homogeneity and the ordering of the self-assembled monolayer were investigated by dynamic water contact angle measurements and polarization-modulation infrared reflection-absorption spectroscopy. PMID:20166727

  7. Long-range eye tracking: A feasibility study

    SciTech Connect

    Jayaweera, S.K.; Lu, Shin-yee

    1994-08-24

    The design considerations for a long-range Purkinje effects based video tracking system using current technology is presented. Past work, current experiments, and future directions are thoroughly discussed, with an emphasis on digital signal processing techniques and obstacles. It has been determined that while a robust, efficient, long-range, and non-invasive eye tracking system will be difficult to develop, such as a project is indeed feasible.

  8. Communication: Control of chemical reactions using electric field gradients

    NASA Astrophysics Data System (ADS)

    Deshmukh, Shivaraj D.; Tsori, Yoav

    2016-05-01

    We examine theoretically a new idea for spatial and temporal control of chemical reactions. When chemical reactions take place in a mixture of solvents, an external electric field can alter the local mixture composition, thereby accelerating or decelerating the rate of reaction. The spatial distribution of electric field strength can be non-trivial and depends on the arrangement of the electrodes producing it. In the absence of electric field, the mixture is homogeneous and the reaction takes place uniformly in the reactor volume. When an electric field is applied, the solvents separate and the reactants are concentrated in the same phase or separate to different phases, depending on their relative miscibility in the solvents, and this can have a large effect on the kinetics of the reaction. This method could provide an alternative way to control runaway reactions and to increase the reaction rate without using catalysts.

  9. Communication: Control of chemical reactions using electric field gradients.

    PubMed

    Deshmukh, Shivaraj D; Tsori, Yoav

    2016-05-21

    We examine theoretically a new idea for spatial and temporal control of chemical reactions. When chemical reactions take place in a mixture of solvents, an external electric field can alter the local mixture composition, thereby accelerating or decelerating the rate of reaction. The spatial distribution of electric field strength can be non-trivial and depends on the arrangement of the electrodes producing it. In the absence of electric field, the mixture is homogeneous and the reaction takes place uniformly in the reactor volume. When an electric field is applied, the solvents separate and the reactants are concentrated in the same phase or separate to different phases, depending on their relative miscibility in the solvents, and this can have a large effect on the kinetics of the reaction. This method could provide an alternative way to control runaway reactions and to increase the reaction rate without using catalysts. PMID:27208928

  10. Biofilm responses to smooth flow fields and chemical gradients in novel microfluidic flow cells.

    PubMed

    Song, Jisun L; Au, Kelly H; Huynh, Kimberly T; Packman, Aaron I

    2014-03-01

    We present two novel microfluidic flow cells developed to provide reliable control of flow distributions and chemical gradients in biofilm studies. We developed a single-inlet microfluidic flow cell to support biofilm growth under a uniform velocity field, and a double-inlet flow cell to provide a very smooth transverse concentration gradient. Both flow cells consist of a layer of polydimethylsiloxane (PDMS) bonded to glass cover slips and were fabricated using the replica molding technique. We demonstrate the capabilities of the flow cells by quantifying flow patterns before and after growth of Pseudomonas aeruginosa biofilms through particle imaging velocimetry, and by evaluating concentration gradients within the double-inlet microfluidic flow cell. Biofilm growth substantially increased flow complexity by diverting flow around biomass, creating high- and low-velocity regions and surface friction. Under a glucose gradient in the double-inlet flow cell, P. aeruginosa biofilms grew in proportion to the local glucose concentration, producing distinct spatial patterns in biofilm biomass relative to the imposed glucose gradient. When biofilms were subjected to a ciprofloxacin gradient, spatial patterns of fractions of dead cells were also in proportion to the local antibiotic concentration. These results demonstrate that the microfluidic flow cells are suitable for quantifying flow complexities resulting from flow-biofilm interactions and investigating spatial patterns of biofilm growth under chemical gradients. These novel microfluidic flow cells will facilitate biofilm research that requires flow control and in situ imaging, particularly investigations of biofilm-environment interactions. PMID:24038055

  11. Biofilm responses to smooth flow fields and chemical gradients in novel microfluidic flow cells

    PubMed Central

    Song, Jisun L.; Au, Kelly H.; Huynh, Kimberly T.

    2013-01-01

    We present two novel microfluidic flow cells developed to provide reliable control of flow distributions and chemical gradients in biofilm studies. We developed a single-inlet microfluidic flow cell to support biofilm growth under a uniform velocity field, and a double-inlet flow cell to provide a very smooth transverse concentration gradient. Both flow cells consist of a layer of polydimethylsiloxane (PDMS) bonded to glass cover slips and were fabricated using the replica molding technique. We demonstrate the capabilities of the flow cells by quantifying flow patterns before and after growth of Pseudomonas aeruginosa biofilms through particle imaging velocimetry, and by evaluating concentration gradients within the double-inlet microfluidic flow cell. Biofilm growth substantially increased flow complexity by diverting flow around biomass, creating high- and low-velocity regions and surface friction. Under a glucose gradient in the double-inlet flow cell, P. aeruginosa biofilms grew in proportion to the local glucose concentration, producing distinct spatial patterns in biofilm biomass relative to the imposed glucose gradient. When biofilms were subjected to a ciprofloxacin gradient, spatial patterns of fractions of dead cells were also in proportion to the local antibiotic concentration. These results demonstrate that the microfluidic flow cells are suitable for quantifying flow complexities resulting from flow-biofilm interactions and investigating spatial patterns of biofilm growth under chemical gradients. These novel microfluidic flow cells will facilitate biofilm research that requires flow control and in situ imaging, particularly investigations of biofilm-environment interactions. PMID:24038055

  12. Long-range corrected density functional theory with linearly-scaled HF exchange

    NASA Astrophysics Data System (ADS)

    Song, Jong-Won; Hirao, Kimihiko

    2015-12-01

    Long-range corrected density functional theory (LC-DFT) attracts many chemists' attentions as a quantum chemical method to be applied to large molecular system and its property calculations. However, the expensive time cost to evaluate the long-range HF exchange is a big obstacle to be overcome to be applied to the large molecular systems and the solid state materials. Upon this problem, we propose a linear-scaling method of the HF exchange integration, in particular, for the LC-DFT hybrid functional.

  13. Long-range corrected density functional theory with linearly-scaled HF exchange

    SciTech Connect

    Song, Jong-Won; Hirao, Kimihiko

    2015-12-31

    Long-range corrected density functional theory (LC-DFT) attracts many chemists’ attentions as a quantum chemical method to be applied to large molecular system and its property calculations. However, the expensive time cost to evaluate the long-range HF exchange is a big obstacle to be overcome to be applied to the large molecular systems and the solid state materials. Upon this problem, we propose a linear-scaling method of the HF exchange integration, in particular, for the LC-DFT hybrid functional.

  14. Long-Range Interactions Restrict Water Transport in Pyrophyllite Interlayers.

    PubMed

    Zarzycki, Piotr; Gilbert, Benjamin

    2016-01-01

    Water diffusion within smectite clay interlayers is reduced by confinement and hence is highly determined by the interlayer spacings that are adopted during swelling. However, a molecular understanding of the short- and long-range forces governing interlayer water structure and dynamics is lacking. Using molecular dynamics simulations of water intercalated between pyrophyllite (smectite prototype) layers we provide a detailed picture of the variation of interlayered water mobility accompanying smectite expansion. Subtle changes in hydrogen bond network structure cause significant changes in water mobility that is greater for stable hydration states and reduced for intermediate separations. By studying pyrophyllite with and without external water we reveal that long-range electrostatic forces apply a restraining effect upon interlayer water mobility. Our findings are relevant for broad range of confining nanostructures with walls thin enough to permit long-range interactions that could affect the mobility of confined solvent molecules and solute species. PMID:27118164

  15. Entanglement area law for long-range interacting systems

    NASA Astrophysics Data System (ADS)

    Gong, Zhexuan; Foss-Feig, Michael; Brandao, Fernando G. S. L.; Gorshkov, Alexey V.

    Area laws for entanglement provide crucial insight into the low-energy behavior of many-body systems and are intimately connected to the efficiency of classical computational methods. For 1D systems, an area law was rigorously proven for ground states of gapped Hamiltonians with local interactions and for states with exponentially decaying correlations. In the presence of long-range interactions, the proof of an area law for gapped ground states becomes much more challenging because long-range interactions can change the effective dimensionality of the system and introduce correlations decaying slower than an exponential. Based on recent theoretical advances that reveal strong remnants of locality in quenched systems with power-law decaying interactions, we prove an area law for a large class of gapped Hamiltonians with long-range interactions. As an intermediate step, we prove tight bounds on the decay of ground-state correlations.

  16. Long-Range Interactions Restrict Water Transport in Pyrophyllite Interlayers

    PubMed Central

    Zarzycki, Piotr; Gilbert, Benjamin

    2016-01-01

    Water diffusion within smectite clay interlayers is reduced by confinement and hence is highly determined by the interlayer spacings that are adopted during swelling. However, a molecular understanding of the short- and long-range forces governing interlayer water structure and dynamics is lacking. Using molecular dynamics simulations of water intercalated between pyrophyllite (smectite prototype) layers we provide a detailed picture of the variation of interlayered water mobility accompanying smectite expansion. Subtle changes in hydrogen bond network structure cause significant changes in water mobility that is greater for stable hydration states and reduced for intermediate separations. By studying pyrophyllite with and without external water we reveal that long-range electrostatic forces apply a restraining effect upon interlayer water mobility. Our findings are relevant for broad range of confining nanostructures with walls thin enough to permit long-range interactions that could affect the mobility of confined solvent molecules and solute species. PMID:27118164

  17. Long-range interactions in lattice field theory

    SciTech Connect

    Rabin, J.M.

    1981-06-01

    Lattice quantum field theories containing fermions can be formulated in a chirally invariant way provided long-range interactions are introduced. It is established that in weak-coupling perturbation theory such a lattice theory is renormalizable when the corresponding continuum theory is, and that the continuum theory is indeed recovered in the perturbative continuum limit. In the strong-coupling limit of these theories one is led to study an effective Hamiltonian describing a Heisenberg antiferromagnet with long-range interactions. Block-spin renormalization group methods are used to find a critical rate of falloff of the interactions, approximately as inverse distance squared, which separates a nearest-neighbor-antiferromagnetic phase from a phase displaying identifiable long-range effects. A duality-type symmetry is present in some block-spin calculations.

  18. Application of advanced technology to future long-range aircraft

    NASA Technical Reports Server (NTRS)

    Schrader, O. E.

    1976-01-01

    The objective of this paper is to provide an overview assessment of three separate programs at Langley Research Center that have incorporated advanced technology into the design of long-range passenger and cargo aircraft. The first technology centers around the use of an span-loaded cargo aircraft with the payload distributed along the wing. This concept has the potential for reduced structural weights. The second technology is the application of laminar flow control (LFC) to the aircraft to reduce the aerodynamic drag. The use of LFC can reduce the fuel requirements during long-range cruise. The last program evaluates the production of alternate aircraft fuels from coal and the use of liquid hydrogen as an aircraft fuel. Coal-derived hydrogen as an aircraft fuel offers both the prospect for reduced dependence on petroleum fuels and improved performance for long-range aircraft.

  19. Fourth International Symposium on Long-Range Sound Propagation

    NASA Technical Reports Server (NTRS)

    Willshire, William L., Jr. (Compiler)

    1990-01-01

    Long range sound propagation is an aspect of many acoustical problems ranging from en route aircraft noise to the acoustic detection of aircraft. Over the past decade, the University of Mississippi and the Open University of England, together with a third institution, have held a symposium approx. every 2 years so that experts in the field of long range propagation could exchange information on current research, identify areas needing additional work, and coordinate activities as much as possible. The Fourth International Symposium on Long Range Sound Propagation was jointly sponsored by the University of Mississippi, the Open University of England, and NASA. Papers were given in the following areas: ground effects on propagation; infrasound propagation; and meteorological effects on sound propagation. A compilation of the presentations made at the symposium is presented along with a list of attendees, and the agenda.

  20. Memory and long-range correlations in chess games

    NASA Astrophysics Data System (ADS)

    Schaigorodsky, Ana L.; Perotti, Juan I.; Billoni, Orlando V.

    2014-01-01

    In this paper we report the existence of long-range memory in the opening moves of a chronologically ordered set of chess games using an extensive chess database. We used two mapping rules to build discrete time series and analyzed them using two methods for detecting long-range correlations; rescaled range analysis and detrended fluctuation analysis. We found that long-range memory is related to the level of the players. When the database is filtered according to player levels we found differences in the persistence of the different subsets. For high level players, correlations are stronger at long time scales; whereas in intermediate and low level players they reach the maximum value at shorter time scales. This can be interpreted as a signature of the different strategies used by players with different levels of expertise. These results are robust against the assignation rules and the method employed in the analysis of the time series.

  1. Long-range oil and gas forecasting methodologies: literature survey

    SciTech Connect

    Cherniavsky, E.A.

    1980-08-01

    Performance of long-range energy system analyses requires the capability to project conventional domestic oil and gas supplies in the long term. The objective of the Long-range Forecasting Methodology project is to formulate an approach to this problem which will be compatible with the principal tool employed by the Energy Information Administration of the Department of Energy for long-range energy system analyses, the Long-term Energy Analysis Package (LEAP). This paper reports on projection methodologies that have appeared in the literature, evaluates them in terms of their applicability to the LEAP framework, and discusses the principal determinants of conventional domestic oil and gas supply in the long run.

  2. Long-Range Beam-Beam Compensation Using Wires

    NASA Astrophysics Data System (ADS)

    Zimmermann, F.; Schmickler, H.

    At the LHC, the effect of unavoidable long-range beam-beam collisions reduces the dynamic aperture, calling for a minimum crossing angle. A wire compensator partially cancels the effect of the long-range collisions, and may allow operation with reduced crossing angle or decreased beta function at the interaction point, thereby increasing the (virtual) peak luminosity. In this chapter, we describe the proposed compensation scheme, previous validation experiments with a single beam and multiple wires at the SPS, simulations for the LHC high-luminosity upgrade, a demonstrator project with real long-range encounters foreseen in the LHC proper, and the possible use of a low-energy electron beam as a future ultimate "wire".

  3. Coding constraints modulate chemically spontaneous mutational replication gradients in mitochondrial genomes.

    PubMed

    Seligmann, Hervé

    2012-03-01

    Distances from heavy and light strand replication origins determine duration mitochondrial DNA remains singlestranded during replication. Hydrolytic deaminations from A->G and C->T occur more on single- than doublestranded DNA. Corresponding replicational nucleotide gradients exist across mitochondrial genomes, most at 3rd, least 2(nd) codon positions. DNA singlestrandedness during RNA transcription causes gradients mainly in long-lived species with relatively slow metabolism (high transcription/replication ratios). Third codon nucleotide contents, evolutionary results of mutation cumulation, follow replicational, not transcriptional gradients in Homo; observed human mutations follow transcriptional gradients. Synonymous third codon position transitions potentially alter adaptive off frame information. No mutational gradients occur at synonymous positions forming off frame stops (these adaptively stop early accidental frameshifted protein synthesis), nor in regions coding for putative overlapping genes according to an overlapping genetic code reassigning stop codons to amino acids. Deviation of 3rd codon nucleotide contents from deamination gradients increases with coding importance of main frame 3rd codon positions in overlapping genes (greatest if these are 2(nd) position in overlapping genes). Third codon position deamination gradients calculated separately for each codon family are strongest where synonymous transitions are rarely pathogenic; weakest where transitions are frequently pathogenic. Synonymous mutations affect translational accuracy, such as error compensation of misloaded tRNAs by codon-anticodon mismatches (prevents amino acid misinsertion despite tRNA misacylation), a potential cause of pathogenic mutations at synonymous codon positions. Indeed, codon-family-specific gradients are inversely proportional to error compensation associated with gradient-promoted transitions. Deamination gradients reflect spontaneous chemical reactions in

  4. Design of a high capacity long range cargo aircraft

    NASA Technical Reports Server (NTRS)

    Weisshaar, Terrence A.

    1994-01-01

    This report examines the design of a long range cargo transport to attempt to reduce ton-mile shipping costs and to stimulate the air cargo market. This design effort involves the usual issues but must also include consideration of: airport terminal facilities; cargo loading and unloading; and defeating the 'square-cube' law to design large structures. This report reviews the long range transport design problem and several solutions developed by senior student design teams at Purdue University. The results show that it will be difficult to build large transports unless the infrastructure is changed and unless the basic form of the airplane changes so that aerodynamic and structural efficiencies are employed.

  5. Long-range dependence in interest rates and monetary policy

    NASA Astrophysics Data System (ADS)

    Cajueiro, Daniel O.; Tabak, Benjamin M.

    2008-01-01

    This Letter studies the dynamics of Brazilian interest rates for short-term maturities. The Letter employs developed techniques in the econophysics literature and tests for long-range dependence in the term structure of these interest rates for the last decade. Empirical results suggest that the degree of long-range dependence has changed over time due to changes in monetary policy, specially in the short-end of the term structure of interest rates. Therefore, we show that it is possible to identify monetary arrangements using these techniques from econophysics.

  6. Long-range correlation in cosmic microwave background radiation.

    PubMed

    Movahed, M Sadegh; Ghasemi, F; Rahvar, Sohrab; Tabar, M Reza Rahimi

    2011-08-01

    We investigate the statistical anisotropy and gaussianity of temperature fluctuations of Cosmic Microwave Background (CMB) radiation data from the Wilkinson Microwave Anisotropy Probe survey, using the Multifractal Detrended Fluctuation Analysis, Rescaled Range, and Scaled Windowed Variance methods. Multifractal Detrended Fluctuation Analysis shows that CMB fluctuations has a long-range correlation function with a multifractal behavior. By comparing the shuffled and surrogate series of CMB data, we conclude that the multifractality nature of the temperature fluctuation of CMB radiation is mainly due to the long-range correlations, and the map is consistent with a gaussian distribution. PMID:21928945

  7. Long-range correction for dipolar fluids at planar interfaces

    NASA Astrophysics Data System (ADS)

    Werth, Stephan; Horsch, Martin; Hasse, Hans

    2015-12-01

    A slab-based long-range correction for dipolar interactions in molecular dynamics simulation of systems with a planar geometry is presented and applied to simulate vapour-liquid interfaces. The present approach is validated with respect to the saturated liquid density and the surface tension of the Stockmayer fluid and a molecular model for ethylene oxide. The simulation results exhibit no dependence on the cut-off radius for radii down to 1 nm, proving that the long-range correction accurately captures the influence of the dipole moment on the intermolecular interaction energies and forces as well as the virial and the surface tension.

  8. Small long-range alpha detector (LRAD) with computer readout

    SciTech Connect

    MacArthur, D.W.; Allander, K.S.; Bounds, J.A.; Butterfield, K.B.

    1991-10-01

    The small long-range alpha detector developed by N-2 was described in detail in the Los Alamos publication LA-12073-MS, Long-Range Alpha Detector,'' published in 1991. Since publication of that report, a computerized data acquisition system has been added to the LRAD detector. In addition to detailing the new data acquisition system, we discuss new data generated with the enhanced system, including measurements of (1) ultimate sensitivity; (2) detector linearity; (3) ion lifetime; and (4) characteristics. Furthermore, we have expanded our understanding of ion recombination and statistical noise effects in the LRAD and have addressed them here as well as several proposed applications. 6 refs., 30 figs.

  9. Long-Range Beam-Beam Compensation in RHIC

    SciTech Connect

    Kim, Hyung Jin; Sen, Tanaji; Fischer, Wolfram; /Brookhaven

    2010-05-01

    In order to avoid the effects of long-range beam-beam interactions which produce beam blow-up and deteriorate beam life time, a compensation scheme with current carrying wires has been proposed. Two long-range beam-beam compensators were installed in RHIC rings in 2006. The effects of the compensators have been experimentally investigated. An indication was observed that the compensators are beneficial to beam life time in measurements performed in RHIC during 2009. In this paper, we report the effects of wire compensator on beam loss and emittance for proton-proton beams at collision energy.

  10. Strategic Long Range Planning for Universities. AIR Forum 1980 Paper.

    ERIC Educational Resources Information Center

    Baker, Michael E.

    The use of strategic long-range planning at Carnegie-Mellon University (CMU) is discussed. A structure for strategic planning analysis that integrates existing techniques is presented, and examples of planning activities at CMU are included. The key concept in strategic planning is competitive advantage: if a university has a competitive…

  11. New Long-Range Interaction between Dipolar Chains

    NASA Astrophysics Data System (ADS)

    Gross, Mark; Kiskamp, Stephen

    1997-09-01

    The interaction between two finite chains of dipoles is treated in a systematic fashion by considering perturbations from the idealized case of two infinite, uniform, parallel chains. A long-range attractive interaction is obtained which survives the zero-temperature limit. Thermal effects increase the range of attraction. Applications to magnetorheological fluids are discussed.

  12. Long-Range Strategic Planning: The Rochester Experience.

    ERIC Educational Resources Information Center

    Schultz, John M.; Anthony, Deborah L.

    The administration of Rochester Community Schools (Michigan) initiated a process for long-range strategic planning in 1984, described in this synopsis. Strategic planning is an ongoing, evolutionary process of defining the business one is in or should be in; establishing organizational goals and objectives; and developing and implementing…

  13. Long-range contributions to double beta decay revisited

    NASA Astrophysics Data System (ADS)

    Helo, J. C.; Hirsch, M.; Ota, T.

    2016-06-01

    We discuss the systematic decomposition of all dimension-7 ( d = 7) lepton number violating operators. These d = 7 operators produce momentum enhanced contributions to the long-range part of the 0νββ decay amplitude and thus are severely constrained by existing half-live limits. In our list of possible models one can find contributions to the long-range amplitude discussed previously in the literature, such as the left-right symmetric model or scalar leptoquarks, as well as some new models not considered before. The d = 7 operators generate Majorana neutrino mass terms either at tree-level, 1-loop or 2-loop level. We systematically compare constraints derived from the mass mechanism to those derived from the long-range 0 νββ decay amplitude and classify our list of models accordingly. We also study one particular example decomposition, which produces neutrino masses at 2-loop level, can fit oscillation data and yields a large contribution to the long-range 0 νββ decay amplitude, in some detail.

  14. RESIDENCE TIME OF ATMOSPHERIC POLLUTANTS AND LONG-RANGE TRANSPORT

    EPA Science Inventory

    The Lagrangian trajectory model which is suitable for the study of long-range transport of pollutants, is developed. The computer program is capable of calculating trajectories over the region of the U.S. using routine sounding data. The output consists of tables of locations of ...

  15. Long-range correlation analysis of economic news flow intensity

    NASA Astrophysics Data System (ADS)

    Sidorov, S. P.; Faizliev, A. R.; Balash, V. A.; Korobov, E. A.

    2016-02-01

    The goal of the paper is to examine the auto-correlation properties for time series of the news flow intensity using different methods, such as the fluctuation analysis, the detrended fluctuation analysis and the detrending moving average analysis. Empirical findings for news analytics data show the presence of long-range correlations for the time series of news intensity data.

  16. LONG RANGE DEVELOPMENT PLAN FOR HONOLULU COMMUNITY COLLEGE.

    ERIC Educational Resources Information Center

    KILIAN, OTTO H.

    THE LONG RANGE DEVELOPMENT PLAN FOR HONOLULU COMMUNITY COLLEGE DESCRIBES VERY BRIEFLY A WIDE RANGE OF TOPICS AS FOLLOWS--(1) SITE CONDITIONS--VICINITY MAP, PHYSICAL CHARACTERISTICS, ZONING AND LAND USE, ASSESSED VALUATIONS, TRAFFIC ANALYSIS, (2) EXISTING CAMPUS--TYPE, AGE AND CONDITION OF NEIGHBORHOOD AND CAMPUS STRUCTURES, CAMPUS PLAN, CAMPUS…

  17. "MAPseq"-uencing Long-Range Neuronal Projections.

    PubMed

    Yonehara, Keisuke; Roska, Botond

    2016-09-01

    Kebschull et al. (2016a) describe "MAPseq," which tags individual neurons from a specific brain region with individual mRNA barcodes and sequences these barcodes in other brain regions. This allows the simultaneous mapping of long-range neuronal projections at single-cell resolution. PMID:27608754

  18. Microcanonical Analysis on a System with Long-Range Interactions

    NASA Astrophysics Data System (ADS)

    Hou, Ji-Xuan; Yu, Xu-Chen; Hou, Jing-Min

    2016-09-01

    We study a long-range interacting spin chain placed in a staggered magnetic field using microcanonical approach and obtain the global phase diagram. We find that this model exhibits both first order phase transition and second order phase transition separated by a tricritical point, and temperature jump can be observed in the first order phase transition.

  19. Long Range Development Plan, University of California, Riverside.

    ERIC Educational Resources Information Center

    Russell (George Vernon) and Associates, Architects and Planners.

    A long range development plan, conceived as a general guide to final objectives, uses many diagrams and maps to illustrate the text. The plan is predicated on the assumption that orderly and efficient development of site possibilities is subject to ever-changing influences. The following areas are examined--(1) campus environment, (2) academic…

  20. Causality and quantum criticality in long-range lattice models

    NASA Astrophysics Data System (ADS)

    Maghrebi, Mohammad F.; Gong, Zhe-Xuan; Foss-Feig, Michael; Gorshkov, Alexey V.

    2016-03-01

    Long-range quantum lattice systems often exhibit drastically different behavior than their short-range counterparts. In particular, because they do not satisfy the conditions for the Lieb-Robinson theorem, they need not have an emergent relativistic structure in the form of a light cone. Adopting a field-theoretic approach, we study the one-dimensional transverse-field Ising model with long-range interactions, and a fermionic model with long-range hopping and pairing terms, explore their critical and near-critical behavior, and characterize their response to local perturbations. We deduce the dynamic critical exponent, up to the two-loop order within the renormalization group theory, which we then use to characterize the emergent causal behavior. We show that beyond a critical value of the power-law exponent of the long-range couplings, the dynamics effectively becomes relativistic. Various other critical exponents describing correlations in the ground state, as well as deviations from a linear causal cone, are deduced for a wide range of the power-law exponent.

  1. DEMONSTRATION OF A LONG RANGE TRACER SYSTEM USING PERFLUOROCARBONS

    EPA Science Inventory

    Regional-scale tracer experiments are needed to validate atmospheric dispersion aspects of air pollution models. The capability of a new system, using perfluorocarbon tracers (PFTs), for long-range dispersion experiments at reasonable cost, was demonstrated in two experiments. Tw...

  2. The long-range interaction landscape of gene promoters.

    PubMed

    Sanyal, Amartya; Lajoie, Bryan R; Jain, Gaurav; Dekker, Job

    2012-09-01

    The vast non-coding portion of the human genome is full of functional elements and disease-causing regulatory variants. The principles defining the relationships between these elements and distal target genes remain unknown. Promoters and distal elements can engage in looping interactions that have been implicated in gene regulation. Here we have applied chromosome conformation capture carbon copy (5C) to interrogate comprehensively interactions between transcription start sites (TSSs) and distal elements in 1% of the human genome representing the ENCODE pilot project regions. 5C maps were generated for GM12878, K562 and HeLa-S3 cells and results were integrated with data from the ENCODE consortium. In each cell line we discovered >1,000 long-range interactions between promoters and distal sites that include elements resembling enhancers, promoters and CTCF-bound sites. We observed significant correlations between gene expression, promoter-enhancer interactions and the presence of enhancer RNAs. Long-range interactions show marked asymmetry with a bias for interactions with elements located ∼120 kilobases upstream of the TSS. Long-range interactions are often not blocked by sites bound by CTCF and cohesin, indicating that many of these sites do not demarcate physically insulated gene domains. Furthermore, only ∼7% of looping interactions are with the nearest gene, indicating that genomic proximity is not a simple predictor for long-range interactions. Finally, promoters and distal elements are engaged in multiple long-range interactions to form complex networks. Our results start to place genes and regulatory elements in three-dimensional context, revealing their functional relationships. PMID:22955621

  3. Strategies and Applications for Incorporating Physical and Chemical Signal Gradients in Tissue Engineering

    PubMed Central

    Singh, Milind; Berkland, Cory

    2008-01-01

    From embryonic development to wound repair, concentration gradients of bioactive signaling molecules guide tissue formation and regeneration. Moreover, gradients in cellular and extracellular architecture as well as in mechanical properties are readily apparent in native tissues. Perhaps tissue engineers can take a cue from nature in attempting to regenerate tissues by incorporating gradients into engineering design strategies. Indeed, gradient-based approaches are an emerging trend in tissue engineering, standing in contrast to traditional approaches of homogeneous delivery of cells and/or growth factors using isotropic scaffolds. Gradients in tissue engineering lie at the intersection of three major paradigms in the field—biomimetic, interfacial, and functional tissue engineering—by combining physical (via biomaterial design) and chemical (with growth/differentiation factors and cell adhesion molecules) signal delivery to achieve a continuous transition in both structure and function. This review consolidates several key methodologies to generate gradients, some of which have never been employed in a tissue engineering application, and discusses strategies for incorporating these methods into tissue engineering and implant design. A key finding of this review was that two-dimensional physicochemical gradient substrates, which serve as excellent high-throughput screening tools for optimizing desired biomaterial properties, can be enhanced in the future by transitioning from two dimensions to three dimensions, which would enable studies of cell–protein–biomaterial interactions in a more native tissue–like environment. In addition, biomimetic tissue regeneration via combined delivery of graded physical and chemical signals appears to be a promising strategy for the regeneration of heterogeneous tissues and tissue interfaces. In the future, in vivo applications will shed more light on the performance of gradient-based mechanical integrity and signal

  4. Shear-induced quench of long-range correlations in a liquid mixture.

    PubMed

    Wada, Hirofumi

    2004-03-01

    A static correlation function of concentration fluctuations in a (dilute) binary liquid mixture subjected to both a concentration gradient and uniform shear flow is investigated within the framework of fluctuating hydrodynamics. It is shown that a well-known |c|(2)/k(4) long-range correlation at large wave numbers k crosses over to a weaker divergent one at wave numbers satisfying k<(gamma;/D)(1/2), while an asymptotic shear-controlled power-law dependence is found at much smaller wave numbers given by k<(gamma;/nu)(1/2), where c, gamma;, D, and nu are the mass concentration, the rate of the shear, the mass diffusivity, and the kinematic viscosity of the mixture, respectively. The result will provide the possibility to observe the shear-induced suppression of a long-range correlation experimentally by using, for example, a low-angle light scattering technique. PMID:15089275

  5. Mechanobiological induction of long-range contractility by diffusing biomolecules and size scaling in cell assemblies

    NASA Astrophysics Data System (ADS)

    Dasbiswas, K.; Alster, E.; Safran, S. A.

    2016-06-01

    Mechanobiological studies of cell assemblies have generally focused on cells that are, in principle, identical. Here we predict theoretically the effect on cells in culture of locally introduced biochemical signals that diffuse and locally induce cytoskeletal contractility which is initially small. In steady-state, both the concentration profile of the signaling molecule as well as the contractility profile of the cell assembly are inhomogeneous, with a characteristic length that can be of the order of the system size. The long-range nature of this state originates in the elastic interactions of contractile cells (similar to long-range “macroscopic modes” in non-living elastic inclusions) and the non-linear diffusion of the signaling molecules, here termed mechanogens. We suggest model experiments on cell assemblies on substrates that can test the theory as a prelude to its applicability in embryo development where spatial gradients of morphogens initiate cellular development.

  6. Mechanobiological induction of long-range contractility by diffusing biomolecules and size scaling in cell assemblies.

    PubMed

    Dasbiswas, K; Alster, E; Safran, S A

    2016-01-01

    Mechanobiological studies of cell assemblies have generally focused on cells that are, in principle, identical. Here we predict theoretically the effect on cells in culture of locally introduced biochemical signals that diffuse and locally induce cytoskeletal contractility which is initially small. In steady-state, both the concentration profile of the signaling molecule as well as the contractility profile of the cell assembly are inhomogeneous, with a characteristic length that can be of the order of the system size. The long-range nature of this state originates in the elastic interactions of contractile cells (similar to long-range "macroscopic modes" in non-living elastic inclusions) and the non-linear diffusion of the signaling molecules, here termed mechanogens. We suggest model experiments on cell assemblies on substrates that can test the theory as a prelude to its applicability in embryo development where spatial gradients of morphogens initiate cellular development. PMID:27283037

  7. Mechanobiological induction of long-range contractility by diffusing biomolecules and size scaling in cell assemblies

    PubMed Central

    Dasbiswas, K.; Alster, E.; Safran, S. A.

    2016-01-01

    Mechanobiological studies of cell assemblies have generally focused on cells that are, in principle, identical. Here we predict theoretically the effect on cells in culture of locally introduced biochemical signals that diffuse and locally induce cytoskeletal contractility which is initially small. In steady-state, both the concentration profile of the signaling molecule as well as the contractility profile of the cell assembly are inhomogeneous, with a characteristic length that can be of the order of the system size. The long-range nature of this state originates in the elastic interactions of contractile cells (similar to long-range “macroscopic modes” in non-living elastic inclusions) and the non-linear diffusion of the signaling molecules, here termed mechanogens. We suggest model experiments on cell assemblies on substrates that can test the theory as a prelude to its applicability in embryo development where spatial gradients of morphogens initiate cellular development. PMID:27283037

  8. Microfluidic device with chemical gradient for single-cell cytotoxicity assays.

    PubMed

    Hosokawa, Masahito; Hayashi, Takuma; Mori, Tetsushi; Yoshino, Tomoko; Nakasono, Satoshi; Matsunaga, Tadashi

    2011-05-15

    Here, we report the fabrication of a chemical gradient microfluidic device for single-cell cytotoxicity assays. This device consists of a microfluidic chemical gradient generator and a microcavity array that enables entrapment of cells with high efficiency at 88 ± 6% of the loaded cells. A 2-fold logarithmic chemical gradient generator that is capable of generating a serial 2-fold gradient was designed and then integrated with the microcavity array. High density single-cell entrapment was demonstrated in the device without cell damage, which was performed in 30 s. Finally, we validated the feasibility of this device to perform cytotoxicity assays by exposing cells to potassium cyanide (0-100 μM KCN). The device captured images of 4000 single cells affected by 6 concentrations of KCN and determined cell viability by counting the effected cells. Image scanning of the microcavity array was completed within 10 min using a 10× objective lens and a motorized stage. Aligning cells on the microcavity array eases cell counting, observation, imaging, and evaluation of singular cells. Thus, this platform was able to determine the cytotoxicity of chemicals at a single-cell level, as well as trace the cytotoxicity over time. This device and method will be useful for cytotoxicity analysis and basic biomedical research. PMID:21526753

  9. The impact of long-range transport on secondary aerosol in Northeast Asia

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Carmichael, G. R.; Woo, J.; Zhang, Q.

    2013-12-01

    Long-range transport air pollution is an important issue in Northeast Asia. Large amounts of anthropogenic emissions of SO2 and NOx aggravate air pollution in the region. Most of the emissions come from the industrialized regions along the East China coast. China and Korea are changing their air quality standards for particle pollutant from PM10 to PM2.5 in 2012 and 2015, respectively. According to many previous studies, the long-rang transport of particle matter contributes to Korean air pollution problems, but there are many uncertainties regarding the impact of long range transport. Secondary inorganic aerosols (sulfate, nitrate and ammonium) are dominant ionic contributors to PM2.5. Especially high relative contributions of secondary aerosol appear under westerly wind cases at Korea. The secondary aerosols are produced by converting from SO2 and NOx during the long-range transport, but the contribution varies dramatically depending on season and wind pattern. So far, sulfate is the primary contributor to PM2.5, but nitrate levels are increasing because that NOx emissions in China are increasing dramatically since 2000 due to the growth in power, industry, and transport, while SO2 emissions are trending downward since 2005. We will present chemical characteristics of PM2.5 by westerly long-range transport focused on secondary aerosol, tracking their transport pattern, and production pathway in order to better understand regional air quality modeling of the long-range transport. This study will be performed based on the international study, MICS-Asia phase III, initiated with many researchers. Results using CMAQ with the modeling domain covering Northeast and Southeast China, Korea, and Japan with 15km resolution will be discussed.

  10. Long-range Coulomb interaction in nodal-ring semimetals

    NASA Astrophysics Data System (ADS)

    Huh, Yejin; Moon, Eun-Gook; Kim, Yong Baek

    2016-01-01

    Recently there have been several proposals of materials predicted to be nodal-ring semimetals, where zero energy excitations are characterized by a nodal ring in the momentum space. This class of materials falls between the Dirac-like semimetals and the more conventional Fermi-surface systems. As a step towards understanding this unconventional system, we explore the effects of the long-range Coulomb interaction. Due to the vanishing density of states at the Fermi level, Coulomb interaction is only partially screened and remains long-ranged. Through renormalization group and large-Nf computations, we have identified a nontrivial interacting fixed point. The screened Coulomb interaction at the interacting fixed point is an irrelevant perturbation, allowing controlled perturbative evaluations of physical properties of quasiparticles. We discuss unique experimental consequences of such quasiparticles: acoustic wave propagation, anisotropic dc conductivity, and renormalized phonon dispersion as well as energy dependence of quasiparticle lifetime.

  11. Reaching for the Horizon: The 2015 NSAC Long Range Plan

    NASA Astrophysics Data System (ADS)

    Geesaman, Donald

    2015-10-01

    In April 2014, the Nuclear Science Advisory Committee was charged to conduct a new study of the opportunities and priorities for United States nuclear physics research and to recommend a long range plan for the coordinated advancement of the Nation's nuclear science program over the next decade. The entire community actively contributed to developing this plan. Ideas and goals, new and old, were examined and community priorities were established. The Long Range Plan Working Group gathered at Kitty Hawk, NC to converge on the recommendations. In this talk I will discuss the vision for the future that has emerged from this process. The new plan, ``Reaching for the Horizon,'' offers the promise of great leaps forward in our understanding of nuclear science and new opportunities for nuclear science to serve society. This work was supported by the U. S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

  12. Temperature inversion in long-range interacting systems

    NASA Astrophysics Data System (ADS)

    Teles, Tarcísio N.; Gupta, Shamik; Di Cintio, Pierfrancesco; Casetti, Lapo

    2015-08-01

    Temperature inversions occur in nature, e.g., in the solar corona and in interstellar molecular clouds: Somewhat counterintuitively, denser parts of the system are colder than dilute ones. We propose a simple and appealing way to spontaneously generate temperature inversions in systems with long-range interactions, by preparing them in inhomogeneous thermal equilibrium states and then applying an impulsive perturbation. In similar situations, short-range systems would typically relax to another thermal equilibrium, with a uniform temperature profile. By contrast, in long-range systems, the interplay between wave-particle interaction and spatial inhomogeneity drives the system to nonequilibrium stationary states that generically exhibit temperature inversion. We demonstrate this mechanism in a simple mean-field model and in a two-dimensional self-gravitating system. Our work underlines the crucial role the range of interparticle interaction plays in determining the nature of steady states out of thermal equilibrium.

  13. Sirius: a long-range infrared search and track system

    NASA Astrophysics Data System (ADS)

    Knepper, R.

    1997-08-01

    Sirius is a long range infra red search and track system (LR- IRST) and intended to be used in an anti air warfare (AAW) multisensor suite on board of modern frigates. This Dutch/Canadian development program started 1/1/95 and includes also the evaluation of the system in warm and cold water scenarios. The operational requirements were drafted by both the national navies. The primary task is automatic detection, tracking and reporting of seaskimming missiles at long range. The design is based on recent experiences with IRSTs and the latest technological achievements in the areas of processing capabilities and IR-detectors. In this presentation design drivers and main technical choices are discussed.

  14. Preservation of long range temporal correlations under extreme random dilution

    NASA Astrophysics Data System (ADS)

    Mirzayof, Dror; Ashkenazy, Yosef

    2010-12-01

    Many natural time series exhibit long range temporal correlations that may be characterized by power-law scaling exponents. However, in many cases, the time series have uneven time intervals due to, for example, missing data points, noisy data, and outliers. Here we study the effect of randomly missing data points on the power-law scaling exponents of time series that are long range temporally correlated. The Fourier transform and detrended fluctuation analysis (DFA) techniques are used for scaling exponent estimation. We find that even under extreme dilution of more than 50%, the value of the scaling exponent remains almost unaffected. Random dilution is also applied on heart interbeat interval time series. It is found that dilution of 70%-80% of the data points leads to a reduction of only 8% in the scaling exponent; it is also found that it is possible to discriminate between healthy and heart failure subjects even under extreme dilution of more than 90%.

  15. Quantum Defect Theory for Long-range Anisotropic Interactions

    NASA Astrophysics Data System (ADS)

    Ruzic, Brandon P.; Bohn, John L.; Greene, Chris H.

    2014-05-01

    Quantum Defect Theory (QDT) is a numerically efficient and accurate tool for studying a wide variety of ultracold atomic collisions, where the asymptotic behavior of the atoms is well described by a set of simple parameters. However, analytic formulas for these parameters only exist for the pure - 1 /R6 potential. The long-range parameters are given by simple power law equations in the collision energy, and the bound state energies of different partial waves are simply related. We extend these formulas to encompass all potentials of the form - 1 /Rn , where n > 2 . Moreover, the accuracy of QDT is limited by long-range anisotropic interactions, which, for example, play an important role in collisions of dysprosium or erbium atoms. We present our recent developments on numerically treating this type of interaction within perturbation theory. This work is supported by the US Department of Energy.

  16. Long-range nuclear cruise missiles and stability

    SciTech Connect

    Lewis, G.N.; Postol, T.A. )

    1992-01-01

    Long-range nuclear-armed cruise missiles are highly accurate and are capable of reaching most targets within the United States and the Commonwealth of Independent States (CIS) from launch points beyond their borders. Neither the United States nor the CIS has air surveillance systems capable of providing reliable warning against cruise missiles. Thus it is possible that a small-scale cruise missile attack could go entirely undetected until the nuclear weapons arrived over their targets. Such an attack could destroy the other country's entire strategic bomber force on the ground and severely damage its strategic command and control system, perhaps to the point of endangering the ability of its ICBM force to be launched on warning. This capability makes long-range nuclear cruise missiles potentially one of the most destabilizing of all nuclear weapons.

  17. The design of a long-range megatransport aircraft

    NASA Technical Reports Server (NTRS)

    Weisshaar, Terrence A.; Allen, Carl L.

    1992-01-01

    Aircraft manufacturers are examining the market and feasibility of long-range passenger aircraft carrying more than 600 passengers. These aircraft would carry travelers at reduced cost and, at the same time, reduce congestion around major airports. The design of a large, long-range transport involves broad issues such as: the integration of airport terminal facilities; passenger loading and unloading; trade-offs between aircraft size and the cost to reconfigure these existing facilities; and, defeating the 'square-cube' law. Thirteen Purdue design teams generated RFP's that defined passenger capability and range, based upon team perception of market needs and infrastructure constraints. Turbofan engines were designed by each group to power these aircraft. The design problem and the variety of solutions developed are reviewed.

  18. Travel: a long-range goal of retired women.

    PubMed

    Staats, Sara; Pierfelice, Loretta

    2003-09-01

    The authors surveyed retired persons (predominately women) with regard to their immediate, intermediate, and long-range activities following retirement. As predicted, leisure travel emerged as a frequent long-range goal for persons retired more than 5 years. The travel activity preferences of long-retired older women present challenges and opportunities to both researchers and marketers. Length of trips and frequency of trips have been predicted from regression models, with trip length in particular being well predicted by the problem of daily life hassles. A theoretical model of continued post-retirement travel is presented as a variant of Solomon's opponent process theory of affect (R. L. Solomon, 1980). The authors suggest that to the degree that places traveled to are varied and different, older people may remain stimulated and continue to enjoy retirement. PMID:14629078

  19. Long-range correlation analysis of urban traffic data

    NASA Astrophysics Data System (ADS)

    Sheng, Peng; Wang, Jun-Feng; Tang, Tie-Qiao; Zhao, Shu-Long

    2010-08-01

    This paper investigates urban traffic data by analysing the long-range correlation with detrended fluctuation analysis. Through a large number of real data collected by the travel time detection system in Beijing, the variation of flow in different time periods and intersections is studied. According to the long-range correlation in different time scales, it mainly discusses the effect of intersection location in road net, people activity customs and special traffic controls on urban traffic flow. As demonstrated by the obtained results, the urban traffic flow represents three-phase characters similar to highway traffic. Moreover, compared by the two groups of data obtained before and after the special traffic restrictions (vehicles with special numbered plates only run in a special workday) enforcement, it indicates that the rules not only reduce the flow but also avoid irregular fluctuation.

  20. Periodic discrete energy for long-range potentials

    NASA Astrophysics Data System (ADS)

    Hardin, D. P.; Saff, E. B.; Simanek, B.

    2014-12-01

    We consider periodic energy problems in Euclidean space with a special emphasis on long-range potentials that cannot be defined through the usual infinite sum. One of our main results builds on more recent developments of Ewald summation to define the periodic energy corresponding to a large class of long-range potentials. Two particularly interesting examples are the logarithmic potential and the Riesz potential when the Riesz parameter is smaller than the dimension of the space. For these examples, we use analytic continuation methods to provide concise formulas for the periodic kernel in terms of the Epstein Hurwitz Zeta function. We apply our energy definition to deduce several properties of the minimal energy including the asymptotic order of growth and the distribution of points in energy minimizing configurations as the number of points becomes large. We conclude with some detailed calculations in the case of one dimension, which shows the utility of this approach.

  1. Long-range mutual information and topological uncertainty principle

    NASA Astrophysics Data System (ADS)

    Jian, Chao-Ming; Kim, Isaac; Qi, Xiao-Liang

    Ordered phases in Landau paradigm can be diagnosed by a local order parameter, whereas topologically ordered phases cannot be detected in such a way. In this paper, we propose long-range mutual information (LRMI) as a unified diagnostic for both conventional long-range order and topological order. Using the LRMI, we characterize orders in n +1D gapped systems as m-membrane condensates with 0 <= m <= n-1. The familiar conventional order and 2 +1D topological orders are respectively identified as 0-membrane and 1-membrane condensates. We propose and study the topological uncertainty principle, which describes the non-commuting nature of non-local order parameters in topological orders.

  2. Information propagation and equilibration in long-range Kitaev chains

    NASA Astrophysics Data System (ADS)

    Van Regemortel, Mathias; Sels, Dries; Wouters, Michiel

    2016-03-01

    We study the propagation of information through a Kitaev chain with long-range pairing interactions. Although the Lieb-Robinson bound is violated in the strict sense for long-range interacting systems, we illustrate that a major amount of information in this model still propagates ballistically on a light cone. We find a pronounced effect of the interaction range on the decay of the mutual information between spatially disconnected subsystems. A significant amount of information is shared at timelike separations. This regime is accompanied by very slow equilibration of local observables. As the Kitaev model is quasifree, we illustrate how the distribution of quasiparticle group velocities explains the physics of this system qualitatively.

  3. Long range Ising model for credit risk modeling

    NASA Astrophysics Data System (ADS)

    Molins, Jordi; Vives, Eduard

    2005-07-01

    Within the framework of maximum entropy principle we show that the finite-size long-range Ising model is the adequate model for the description of homogeneous credit portfolios and the computation of credit risk when default correlations between the borrowers are included. The exact analysis of the model suggest that when the correlation increases a first-order-like transition may occur inducing a sudden risk increase.

  4. Long range science scheduling for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Miller, Glenn; Johnston, Mark

    1991-01-01

    Observations with NASA's Hubble Space Telescope (HST) are scheduled with the assistance of a long-range scheduling system (SPIKE) that was developed using artificial intelligence techniques. In earlier papers, the system architecture and the constraint representation and propagation mechanisms were described. The development of high-level automated scheduling tools, including tools based on constraint satisfaction techniques and neural networks is described. The performance of these tools in scheduling HST observations is discussed.

  5. The design of a long range megatransport aircraft

    NASA Technical Reports Server (NTRS)

    Weisshaar, Terrence A.; Allen, Carl L.

    1992-01-01

    During the period from August 1991 - June 1992 two design classes at Purdue University participated in the design of a long range, high capacity transport aircraft, dubbed the megatransport. Thirteen Purdue design teams generated RFP's that defined passenger capability and range, based upon team perception of market needs and infrastructure constraints. Turbofan engines were designed by each group to power these aircraft. The design problem and the variety of solutions developed are described in an attached paper.

  6. Long Range Interactions With Laser Cooled Neutral Atoms

    SciTech Connect

    Gattobigio, Giovanni Luca; Michaud, Franck; Labeyrie, Guillaume; Kaiser, Robin; Loureiro, Jorge; Mendonca, Jose Tito; Tercas, Hugo; Pohl, Thomas

    2008-09-07

    Multiple scattering of light in a trap of laser cooled neutral atoms leads to repulsion forces between the atoms. The corresponding interactions have long range behavior in 1/r{sup 2} and are thus similar to Coulomb interaction in an one component confined plasma. Consequences of these interactions will be described in this paper, including the limitation of the spatial density one can obtain in such systems and self-sustained oscillations of the cloud.

  7. Long-range quantum entanglement in noisy cluster states

    SciTech Connect

    Raussendorf, Robert; Bravyi, Sergey; Harrington, Jim

    2005-06-15

    We describe a phase transition for long-range entanglement in a three-dimensional cluster state affected by noise. The partially decohered state is modeled by the thermal state of a short-range translation-invariant Hamiltonian. We find that the temperature at which the entanglement length changes from infinite to finite is nonzero. We give an upper and lower bound to this transition temperature.

  8. Emergent long-range couplings in arrays of fluid cells

    SciTech Connect

    Abraham, Douglas Bruce

    2014-08-07

    We present a system exhibiting extraordinarily long-range cooperative effects, on a length scale far exceeding the bulk correlation length. We give a theoretical explanation of these phenomena based on the mesoscopic picture of phase coexistence in finite systems, which is confirmedly Monte Carlo (MC) simulation studies. Our work demonstrates that such action-at-a-distance can occur in classical systems involving simple or complex fluids, such as colloid-polymer mixtures, or ferromagnets.

  9. Long-range substantially nonradiative metallo-dielectric waveguide.

    PubMed

    Buckley, Robin; Berini, Pierre

    2009-01-15

    A waveguide structure capable of aggressive bends (r(0)-->0) and long-range propagation (approximately 1.2 dB/mm) is described here. The structure uses a step-index slab to create the vertical confinement and a pair of metallic parallel plates on either side of the core for lateral confinement. The parallel plates are dimensioned to ensure that all modes that would cause radiation loss in a bend are cut off. PMID:19148262

  10. Long-range electrostatic screening in ionic liquids.

    PubMed

    Gebbie, Matthew A; Dobbs, Howard A; Valtiner, Markus; Israelachvili, Jacob N

    2015-06-16

    Electrolyte solutions with high concentrations of ions are prevalent in biological systems and energy storage technologies. Nevertheless, the high interaction free energy and long-range nature of electrostatic interactions makes the development of a general conceptual picture of concentrated electrolytes a significant challenge. In this work, we study ionic liquids, single-component liquids composed solely of ions, in an attempt to provide a novel perspective on electrostatic screening in very high concentration (nonideal) electrolytes. We use temperature-dependent surface force measurements to demonstrate that the long-range, exponentially decaying diffuse double-layer forces observed across ionic liquids exhibit a pronounced temperature dependence: Increasing the temperature decreases the measured exponential (Debye) decay length, implying an increase in the thermally driven effective free-ion concentration in the bulk ionic liquids. We use our quantitative results to propose a general model of long-range electrostatic screening in ionic liquids, where thermally activated charge fluctuations, either free ions or correlated domains (quasiparticles), take on the role of ions in traditional dilute electrolyte solutions. This picture represents a crucial step toward resolving several inconsistencies surrounding electrostatic screening and charge transport in ionic liquids that have impeded progress within the interdisciplinary ionic liquids community. More broadly, our work provides a previously unidentified way of envisioning highly concentrated electrolytes, with implications for diverse areas of inquiry, ranging from designing electrochemical devices to rationalizing electrostatic interactions in biological systems. PMID:26040001

  11. Long-range infrasound monitoring of eruptive volcanoes.

    NASA Astrophysics Data System (ADS)

    Marchetti, Emanuele; Innocenti, Lorenzo; Ulivieri, Giacomo; Lacanna, Giorgio; Ripepe, Maurizio

    2016-04-01

    The efficient long-range propagation in the atmosphere makes infrasound of active volcanoes extremely promising and opens new perspectives for volcano monitoring at large scale. In favourable propagation conditions, long-range infrasound observations can be used to track the occurrence and the duration of volcanic eruptions also at remote non-monitored volcanoes, but its potential to infer volcanic eruptive source term is still debated. We present results of comparing five years of infrasound of eruptive activity at Mt.Etna volcano (Italy) recorded both at local (~5 km) and at regional distances (~600 km) from the source. Infrasound of lava fountains at Etna volcano, occurring in between 2010 and 2015, are analysed in terms of the local and regional wavefield record, and by comparing to all available volcanic source terms (i.e. plume height and mass eruption rates). Besides, the potential of near real-time notification of ongoing volcanic activity at Etna volcano at a regional scale is investigated. In particular we show how long range infrasound, in the case of Etna volcano, can be used to promptly deliver eruption notification and reliability is constrained by the results of the local array. This work is performed in the framework of the H2020 ARISE2 project funded by the EU in the period 2015-2018.

  12. Long-range electrostatic screening in ionic liquids

    PubMed Central

    Gebbie, Matthew A.; Dobbs, Howard A.; Valtiner, Markus; Israelachvili, Jacob N.

    2015-01-01

    Electrolyte solutions with high concentrations of ions are prevalent in biological systems and energy storage technologies. Nevertheless, the high interaction free energy and long-range nature of electrostatic interactions makes the development of a general conceptual picture of concentrated electrolytes a significant challenge. In this work, we study ionic liquids, single-component liquids composed solely of ions, in an attempt to provide a novel perspective on electrostatic screening in very high concentration (nonideal) electrolytes. We use temperature-dependent surface force measurements to demonstrate that the long-range, exponentially decaying diffuse double-layer forces observed across ionic liquids exhibit a pronounced temperature dependence: Increasing the temperature decreases the measured exponential (Debye) decay length, implying an increase in the thermally driven effective free-ion concentration in the bulk ionic liquids. We use our quantitative results to propose a general model of long-range electrostatic screening in ionic liquids, where thermally activated charge fluctuations, either free ions or correlated domains (quasiparticles), take on the role of ions in traditional dilute electrolyte solutions. This picture represents a crucial step toward resolving several inconsistencies surrounding electrostatic screening and charge transport in ionic liquids that have impeded progress within the interdisciplinary ionic liquids community. More broadly, our work provides a previously unidentified way of envisioning highly concentrated electrolytes, with implications for diverse areas of inquiry, ranging from designing electrochemical devices to rationalizing electrostatic interactions in biological systems. PMID:26040001

  13. Long-range intercellular Ca2+ wave patterns

    NASA Astrophysics Data System (ADS)

    Tabi, C. B.; Maïna, I.; Mohamadou, A.; Ekobena, H. P. F.; Kofané, T. C.

    2015-10-01

    Modulational instability is utilized to investigate intercellular Ca2+ wave propagation in an array of diffusively coupled cells. Cells are supposed to be connected via paracrine signaling, where long-range effects, due to the presence of extracellular messengers, are included. The multiple-scale expansion is used to show that the whole dynamics of Ca2+ waves, from the endoplasmic reticulum to the cytosol, can be reduced to a single differential-difference nonlinear equation whose solutions are assumed to be plane waves. Their linear stability analysis is studied, with emphasis on the impact of long-range coupling, via the range parameter s. It is shown that s, as well as the number of interacting cells, importantly modifies the features of modulational instability, as small values of s imply a strong coupling, and increasing its value rather reduces the problem to a first-neighbor one. Our theoretical findings are numerically tested, as the generic equations are fully integrated, leading to the emergence of nonlinear patterns of Ca2+ waves. Strong long-range coupling is pictured by extended trains of breather-like structures whose frequency decreases with increasing s. We also show numerically that the number of interacting cells plays on the spatio-temporal formation of Ca2+ patterns, whilst the quasi-perfect intercellular communication depends on the paracrine coupling parameter.

  14. Segmentation of time series with long-range fractal correlations

    PubMed Central

    Bernaola-Galván, P.; Oliver, J.L.; Hackenberg, M.; Coronado, A.V.; Ivanov, P.Ch.; Carpena, P.

    2012-01-01

    Segmentation is a standard method of data analysis to identify change-points dividing a nonstationary time series into homogeneous segments. However, for long-range fractal correlated series, most of the segmentation techniques detect spurious change-points which are simply due to the heterogeneities induced by the correlations and not to real nonstationarities. To avoid this oversegmentation, we present a segmentation algorithm which takes as a reference for homogeneity, instead of a random i.i.d. series, a correlated series modeled by a fractional noise with the same degree of correlations as the series to be segmented. We apply our algorithm to artificial series with long-range correlations and show that it systematically detects only the change-points produced by real nonstationarities and not those created by the correlations of the signal. Further, we apply the method to the sequence of the long arm of human chromosome 21, which is known to have long-range fractal correlations. We obtain only three segments that clearly correspond to the three regions of different G + C composition revealed by means of a multi-scale wavelet plot. Similar results have been obtained when segmenting all human chromosome sequences, showing the existence of previously unknown huge compositional superstructures in the human genome. PMID:23645997

  15. Acidic loadings in South Korean ecosystems by long-range transport and local emissions

    NASA Astrophysics Data System (ADS)

    Shim, Jae-Myun; Park, Soon-Ung

    2004-10-01

    Exceedances of sulfur and nitrogen critical loads in South Korean ecosystems caused by long-range transport and local emissions of sulfur and nitrogen have been estimated using the maximum critical load of sulfur and the critical load of nutrient nitrogen. The long-term-averaged deposition of sulfur and nitrogen is estimated with a simplified chemical model and the K-mean clustering technique. The three consecutive days of gridded daily mean National Center for Environmental Protection (NCEP) reanalyzed 850 hPa geopotential height fields with and without precipitation on the last day over South Korea are used for clustering of synoptic patterns for the period of 1994-1998. Two emission conditions are simulated for each cluster to estimate long-term averaged depositions of sulfur and nitrogen by long-range transport and local emissions over South Korea. One condition takes all emissions within the simulated domain into account as a base case and the other condition excludes all South Korean emissions but includes all of the other emissions, as a control case. The results of the present study indicate that the contribution of long-range transport to the annual total deposition over South Korea is found to be about 40% (530 eqha-1yr-1) for sulfur and 49% (650 eqha-1yr-1) for nitrogen, of which 55% for sulfur and 58% for nitrogen are contributed by wet deposition. This suggests the importance of wet deposition through the transformed acidic precursors for long-range transport to South Korea's total deposition of sulfur and nitrogen. The estimated exceedance for South Korean ecosystems indicates that the current estimate of total sulfur deposition affects about 42% of the South Korean ecosystems adversely, of which 14% is attributed to South Korean source only and the rest 28% is attributed to long-range transport together with South Korean source. Long-range transport of sulfur itself does not exceed the maximum critical load of sulfur. On the other hand, the current

  16. Long-Range Weather Forecasting In The Ukraine

    NASA Astrophysics Data System (ADS)

    Martazinova, V. F.; Ivanova, E. K.

    2004-12-01

    The operational system for long range weather forecasting (LRF) was developed by Ukrainian Hydrometeorological Institute (UHMI) in the result of studies of general circulation and on the long-range weather forecasting which were began in 1975 by research group leaded by Prof. V. Martazinova. Three key approaches are used in the operational system LRF of UHMI: (1) Floating analog method (FAM); (2) Two-month quasi-periodicity of atmospheric processes in the troposphere of the Northern Hemisphere; (3)Ethalon-field approach. The based on the pattern recognition technique FAM is the continuation of the ideas of former Soviet Union school of long-range forecasting. The traditional method of analog was generalized and advanced as the method of "floating analog" (Martazinova and Sologub, 1986; Martazinova, 1989; 2001). FAM requires only geometrical similarity of the planetary high-level frontal zone and surface pressure on the Northern Hemisphere. The limiting conditions of the coincidence in time and space are lifted. The use of FAM made it possible to reveal the two-month quasi-periodicity of synoptic situation in the Northern Hemisphere. The strong changes of weather within month are predicted using statistical "ethalon field" approach that was developed for classification of meteorological fields in the climate research and the long-range forecasting (Martazinova and Prokhorenko, 1991). The meteorological information for the forecast is used only for the last two months before the target month. The fields of geopotential and pressure are recognized by the "ethalon-field-analog" which corresponds to two-month quasi-periodicity of the ethalon-fields. The forecast for days the strong changes of weather over the territory of Ukraine in next two months. Recognition of daily synoptic situations of last two months by the synoptic situation of two-month quasi-periodicity of atmospheric processes for ethalons when there are waves of cold and heat, strong precipitation, strong

  17. The Characteristics of Long-range Transboundary Inorganic Secondary Aerosols in Northeast Asia

    NASA Astrophysics Data System (ADS)

    Kim, Y. J.; Carmichael, G. R.; Woo, J. H.; Qiang, Z.

    2014-12-01

    Recurrent particle matter episodes greatly influence air quality in Northeast Asia. According to many studies, a major reason is long-range transport of air pollutant. Large amount of emission of chemical compounds aggravate air pollution in the region. Emitted air pollutants mainly come from industrialized regions along the East China coast. It can be transported over downwind region by the prevailing westerlies. The long-rang transported fine particle certainly attributes to air quality in downwind region, but there are many unknowns on the quantity, transport pattern, and secondary aerosol production mechanism despite the fact with many studies have been performed. Major contributors of PM2.5 are inorganic secondary aerosols, sulfate, nitrate and ammonium, in Korea. Especially high relative contributions of inorganic secondary aerosols appear for westerly wind cases. The main pathway of production of inorganic secondary aerosols is produced by converting from SO2 and NOx during the long-range transport but the contribution varies dramatically depending on season and wind pattern. Sulfate is consistently the primary contributor of PM2.5 still now but we should more concern nitrate because that NOx emissions of China is increasing steeply since 2000 by leading powerplant, industry, and transport, despite downward trend of SO2. In order to better understand regional air quality modeling of the long-range transport, international study, MICS-Asia phase III, has been initiated with many researchers. We will present chemical characteristics of PM2.5 long-range transport during westerly wind cases focused on secondary aerosol, tracking their transport pattern, and production pathway. Results using CMAQ with the modeling domain covering Northeast and Southeast China, Korea, and Japan with 15km resolution will be discussed.

  18. The Origin of Long-Range Attraction between Hydrophobes in Water

    PubMed Central

    Despa, Florin; Berry, R. Stephen

    2007-01-01

    When water-coated hydrophobic surfaces meet, direct contacts form between the surfaces, driving water out. However, long-range attractive forces first bring those surfaces close. This analysis reveals the source and strength of the long-range attraction between water-coated hydrophobic surfaces. The origin is in the polarization field produced by the strong correlation and coupling of the dipoles of the water molecules at the surfaces. We show that this polarization field gives rise to dipoles on the surface of the hydrophobic solutes that generate long-range hydrophobic attractions. Thus, hydrophobic aggregation begins with a step in which water-coated nonpolar solutes approach one another due to long-range electrostatic forces. This precursor regime occurs before the entropy increase of releasing the water layers and the short-range van der Waals attraction provide the driving force to “dry out” the contact surface. The effective force of attraction is derived from basic molecular principles, without assumptions of the structure of the hydrophobe-water interaction. The strength of this force can be measured directly from atomic force microscopy images of a hydrophobic molecule tethered to a surface but extending into water, and another hydrophobe attached to an atomic force probe. The phenomenon can be observed in the transverse relaxation rates in water proton magnetic resonance as well. The results shed light on the way water mediates chemical and biological self-assembly, a long outstanding problem. PMID:16997876

  19. Effects of reversible chemical reaction on Li diffusion and stresses in spherical composition-gradient electrodes

    SciTech Connect

    Li, Yong; Zhang, Kai; Zheng, Bailin Zhang, Xiaoqian; Wang, Qi

    2015-06-28

    Composition-gradient electrode materials have been proven to be one of the most promising materials in lithium-ion battery. To study the mechanism of mechanical degradation in spherical composition-gradient electrodes, the finite deformation theory and reversible chemical theory are adopted. In homogeneous electrodes, reversible electrochemical reaction may increase the magnitudes of stresses. However, reversible electrochemical reaction has different influences on stresses in composition-gradient electrodes, resulting from three main inhomogeneous factors—forward reaction rate, backward reaction rate, and reaction partial molar volume. The decreasing transition form of forward reaction rate, increasing transition form of backward reaction rate, and increasing transition form of reaction partial molar volume can reduce the magnitudes of stresses. As a result, capacity fading and mechanical degradation are reduced by taking advantage of the effects of inhomogeneous factors.

  20. Preparation and analysis of chemically gradient functional bioceramic coating formed by pulsed laser deposition.

    PubMed

    Rajesh, P; Muraleedharan, C V; Sureshbabu, S; Komath, Manoj; Varma, Harikrishna

    2012-02-01

    Bioactive ceramic coatings based on calcium phosphates yield better functionality in the human body for a variety of metallic implant devices including orthopaedic and dental prostheses. In the present study chemically and hence functionally gradient bioceramic coating was obtained by pulsed laser deposition method. Calcium phosphate bioactive ceramic coatings based on hydroxyapatite (HA) and tricalcium phosphate (TCP) were deposited over titanium substrate to produce gradation in physico-chemical characteristics and in vitro dissolution behaviour. Sintered targets of HA and α-TCP were deposited in a multi target laser deposition system. The obtained deposits were characterized by X-ray diffraction, fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray analysis. Inductively coupled plasma spectroscopy was used to estimate the in vitro dissolution behaviour of coatings. The variation in mechanical property of the gradient layer was evaluated through scratch test and micro-indentation hardness. The bioactivity was examined in vitro with respect to the ability of HA layer to form on the surface as a result of contact with simulated body fluid. It could be inferred that chemically gradient functional bioceramic coating can be produced by laser deposition of multiple sintered targets with variable chemical composition. PMID:22105226

  1. Chemical gradients in the Milky Way from the RAVE data. I. Dwarf stars

    NASA Astrophysics Data System (ADS)

    Boeche, C.; Siebert, A.; Piffl, T.; Just, A.; Steinmetz, M.; Sharma, S.; Kordopatis, G.; Gilmore, G.; Chiappini, C.; Williams, M.; Grebel, E. K.; Bland-Hawthorn, J.; Gibson, B. K.; Munari, U.; Siviero, A.; Bienaymé, O.; Navarro, J. F.; Parker, Q. A.; Reid, W.; Seabroke, G. M.; Watson, F. G.; Wyse, R. F. G.; Zwitter, T.

    2013-11-01

    Aims: We aim at measuring the chemical gradients of the elements Mg, Al, Si, and Fe along the Galactic radius to provide new constraints on the chemical evolution models of the Galaxy and Galaxy models such as the Besançon model. Thanks to the large number of stars of our RAVE sample we can study how the gradients vary as function of the distance from the Galactic plane. Methods: We analysed three different samples selected from three independent datasets: a sample of 19 962 dwarf stars selected from the RAVE database, a sample of 10 616 dwarf stars selected from the Geneva-Copenhagen Survey (GCS) dataset, and a mock sample (equivalent to the RAVE sample) created by using the GALAXIA code, which is based on the Besançon model. The three samples were analysed by using the very same method for comparison purposes. We integrated the Galactic orbits and obtained the guiding radii (Rg) and the maximum distances from the Galactic plane reached by the stars along their orbits (Zmax). We measured the chemical gradients as functions of Rg at different Zmax. Results: We found that the chemical gradients of the RAVE and GCS samples are negative and show consistent trends, although they are not equal: at Zmax< 0.4 kpc and 4.5 gradient for the RAVE sample is d [Fe/H] /dRg = -0.065 dex kpc-1, whereas for the GCS sample it is d [Fe/H] /dRg = -0.043 dex kpc-1 with internal errors of ±0.002 and ±0.004 dex kpc-1, respectively. The gradients of the RAVE and GCS samples become flatter at larger Zmax. Conversely, the mock sample has a positive iron gradient of d [Fe/H] /dRg = +0.053 ± 0.003 dex kpc-1 at Zmax< 0.4 kpc and remains positive at any Zmax. These positive and unrealistic values originate from the lack of correlation between metallicity and tangential velocity in the Besançon model. In addition, the low metallicity and asymmetric drift of the thick disc causes a shift of the stars towards lower Rg and metallicity which, together with the thin

  2. Acceleration of evolutionary spread by long-range dispersal.

    PubMed

    Hallatschek, Oskar; Fisher, Daniel S

    2014-11-18

    The spreading of evolutionary novelties across populations is the central element of adaptation. Unless populations are well mixed (like bacteria in a shaken test tube), the spreading dynamics depend not only on fitness differences but also on the dispersal behavior of the species. Spreading at a constant speed is generally predicted when dispersal is sufficiently short ranged, specifically when the dispersal kernel falls off exponentially or faster. However, the case of long-range dispersal is unresolved: Although it is clear that even rare long-range jumps can lead to a drastic speedup--as air-traffic-mediated epidemics show--it has been difficult to quantify the ensuing stochastic dynamical process. However, such knowledge is indispensable for a predictive understanding of many spreading processes in natural populations. We present a simple iterative scaling approximation supported by simulations and rigorous bounds that accurately predicts evolutionary spread, which is determined by a trade-off between frequency and potential effectiveness of long-distance jumps. In contrast to the exponential laws predicted by deterministic "mean-field" approximations, we show that the asymptotic spatial growth is according to either a power law or a stretched exponential, depending on the tails of the dispersal kernel. More importantly, we provide a full time-dependent description of the convergence to the asymptotic behavior, which can be anomalously slow and is relevant even for long times. Our results also apply to spreading dynamics on networks with a spectrum of long-range links under certain conditions on the probabilities of long-distance travel: These are relevant for the spread of epidemics. PMID:25368183

  3. Acceleration of evolutionary spread by long-range dispersal

    PubMed Central

    Hallatschek, Oskar; Fisher, Daniel S.

    2014-01-01

    The spreading of evolutionary novelties across populations is the central element of adaptation. Unless populations are well mixed (like bacteria in a shaken test tube), the spreading dynamics depend not only on fitness differences but also on the dispersal behavior of the species. Spreading at a constant speed is generally predicted when dispersal is sufficiently short ranged, specifically when the dispersal kernel falls off exponentially or faster. However, the case of long-range dispersal is unresolved: Although it is clear that even rare long-range jumps can lead to a drastic speedup—as air-traffic–mediated epidemics show—it has been difficult to quantify the ensuing stochastic dynamical process. However, such knowledge is indispensable for a predictive understanding of many spreading processes in natural populations. We present a simple iterative scaling approximation supported by simulations and rigorous bounds that accurately predicts evolutionary spread, which is determined by a trade-off between frequency and potential effectiveness of long-distance jumps. In contrast to the exponential laws predicted by deterministic “mean-field” approximations, we show that the asymptotic spatial growth is according to either a power law or a stretched exponential, depending on the tails of the dispersal kernel. More importantly, we provide a full time-dependent description of the convergence to the asymptotic behavior, which can be anomalously slow and is relevant even for long times. Our results also apply to spreading dynamics on networks with a spectrum of long-range links under certain conditions on the probabilities of long-distance travel: These are relevant for the spread of epidemics. PMID:25368183

  4. Application of advanced technology to future long-range aircraft

    NASA Technical Reports Server (NTRS)

    Schrader, O. E.

    1976-01-01

    An assessment is presented of three separate programs that have incorporated advanced technology into the design of long-range passenger and cargo aircraft. The first technology centers around the use of a span-loaded cargo aircraft with the payload distributed along the wing. The second technology is the application of laminar flow control to the aircraft to reduce the aerodynamic drag. The last program evaluates the production of alternate aircraft fuels from coal and the use of liquid hydrogen as an aircraft fuel.

  5. Impact of atmospheric aerosols on long range image quality

    NASA Astrophysics Data System (ADS)

    LeMaster, Daniel A.; Eismann, Michael T.

    2012-06-01

    Image quality in high altitude long range imaging systems can be severely limited by atmospheric absorption, scattering, and turbulence. Atmospheric aerosols contribute to this problem by scattering target signal out of the optical path and by scattering in unwanted light from the surroundings. Target signal scattering may also lead to image blurring though, in conventional modeling, this effect is ignored. The validity of this choice is tested in this paper by developing an aerosol modulation transfer function (MTF) model for an inhomogeneous atmosphere and then applying it to real-world scenarios using MODTRAN derived scattering parameters. The resulting calculations show that aerosol blurring can be effectively ignored.

  6. Reconfigurable long-range phonon dynamics in optomechanical arrays.

    PubMed

    Xuereb, André; Genes, Claudiu; Pupillo, Guido; Paternostro, Mauro; Dantan, Aurélien

    2014-04-01

    We investigate periodic optomechanical arrays as reconfigurable platforms for engineering the coupling between multiple mechanical and electromagnetic modes and for exploring many-body phonon dynamics. Exploiting structural resonances in the coupling between light fields and collective motional modes of the array, we show that tunable effective long-range interactions between mechanical modes can be achieved. This paves the way towards the implementation of controlled phononic walks and heat transfer on densely connected graphs as well as the coherent transfer of excitations between distant elements of optomechanical arrays. PMID:24745417

  7. INEL D&D Long-Range Plan

    SciTech Connect

    Buckland, R.J.; Kenoyer, D.J.; Preussner, D.H.

    1993-10-01

    This Long-Range Plan presents the Decontamination and Decommissioning (D&D) Program planning status for facilities at the Idaho National Engineering Laboratory (INEL). The plan provides a general description of the D&D Program objectives, management criteria, and philosophy; discusses current activities; and documents the INEL D&D Program cost and schedule estimate projections for the next 15 years. appendices are included that provide INEL D&D project historical information and a comprehensive descriptive summary of each current surplus facility.

  8. Comment on "Temperature inversion in long-range interacting systems".

    PubMed

    Dumin, Yurii V

    2016-06-01

    In the recent paper by Teles et al. [Phys. Rev. E 92, 020101 (2015)]PRESCM1539-375510.1103/PhysRevE.92.020101, it was suggested that the inversed temperature profiles in various astrophysical objects-ranging from the solar corona to the interstellar molecular clouds-can be explained by the specific features of relaxation in the long-range interacting systems. Here, we show that this mechanism can really work in the self-gravitating interstellar gaseous clouds; but it is irrelevant in the solar (and stellar) coronas where stratification of density is produced by the external gravitational field. PMID:27415395

  9. INEL D&D long-range plan

    SciTech Connect

    Buckland, R.J.; Kenoyer, D.J.; LaBuy, S.A.

    1995-09-01

    This Long-Range Plan presents the Decontamination and Dismantlement (D&D) Program planning status for facilities at the Idaho National Engineering Laboratory (INEL). The plan provides a general description of the D&D Program objectives, management criteria, and policy; discusses current activities; and documents the INEL D&D Program cost and schedule estimate projections for the next 15 years. Appendices are included that provide INEL D&D project historical information, a comprehensive descriptive summary of each current D&D surplus facility, and a summary database of all INEL contaminated facilities awaiting or undergoing the facility transition process.

  10. Long-range attraction of particles adhered to lipid vesicles

    NASA Astrophysics Data System (ADS)

    Sarfati, Raphael; Dufresne, Eric R.

    2016-07-01

    Many biological systems fold thin sheets of lipid membrane into complex three-dimensional structures. This microscopic origami is often mediated by the adsorption and self-assembly of proteins on a membrane. As a model system to study adsorption-mediated interactions, we study the collective behavior of micrometric particles adhered to a lipid vesicle. We estimate the colloidal interactions using a maximum likelihood analysis of particle trajectories. When the particles are highly wrapped by a tense membrane, we observe strong long-range attractions with a typical binding energy of 150 kBT and significant forces extending a few microns.

  11. DIII-D tokamak long range plan. Revision 3

    SciTech Connect

    1992-08-01

    The DIII-D Tokamak Long Range Plan for controlled thermonuclear magnetic fusion research will be carried out with broad national and international participation. The plan covers: (1) operation of the DIII-D tokamak to conduct research experiments to address needs of the US Magnetic Fusion Program; (2) facility modifications to allow these new experiments to be conducted; and (3) collaborations with other laboratories to integrate DIII-D research into the national and international fusion programs. The period covered by this plan is 1 November 19983 through 31 October 1998.

  12. A Long Range Science Rover For Future Mars Missions

    NASA Technical Reports Server (NTRS)

    Hayati, Samad

    1997-01-01

    This paper describes the design and implementation currently underway at the Jet Propulsion Laboratory of a long range science rover for future missions to Mars. The small rover prototype, called Rocky 7, is capable of long traverse. autonomous navigation. and science instrument control, carries three science instruments, and can be commanded from any computer platform and any location using the World Wide Web. In this paper we describe the mobility system, the sampling system, the sensor suite, navigation and control, onboard science instruments. and the ground command and control system.

  13. Political Mechanisms for Long-Range Survival and Development

    NASA Astrophysics Data System (ADS)

    Marshall, W.

    As the first species aware of extinction and capable of proactively ensuring our long-term survival and development, it is striking that we do not do so with the rigor, formality, and foresight it requires. Only from a reactive posture have we responded to the challenges of global warfare, human rights, environmental concerns, and sustainable development. Despite our awareness of the possibility for extinction and apocalyptic set-backs to our evolution, and despite the existence of long-range studies-which must still be dramatically increased-proactive global policy implementation regarding our long-term survival and development is arguably non-existent. This lack of long-term policy making can be attributed in part to the lack of formal political mechanisms to facilitate longer-range policy making that extends 30 years or more into the future. Political mechanisms for infusing long-range thinking, research, and strategic planning into the policy-making process can help correct this shortcoming and provide the motivation needed to adequately address long-term challenges with the political rigor required to effectively establish and implement long-term policies. There are some efforts that attempt to address longer-range issues, but those efforts often do not connect to the political process, do not extend 30 or more years into the future, are not well-funded, and are not sufficiently systemic. Political mechanisms for long-range survival and prosperity could correct these inadequacies by raising awareness, providing funding, and most importantly, leveraging political rigor to establish and enforce long-range strategic planning and policies. The feasibility of such mechanisms should first be rigorously studied and assessed in a feasibility study, which could then inform implementation. This paper will present the case for such a study and suggest some possible political mechanisms that should be investigated further in the proposed study. This work is being further

  14. Comment on "Temperature inversion in long-range interacting systems"

    NASA Astrophysics Data System (ADS)

    Dumin, Yurii V.

    2016-06-01

    In the recent paper by Teles et al. [Phys. Rev. E 92, 020101 (2015)], 10.1103/PhysRevE.92.020101, it was suggested that the inversed temperature profiles in various astrophysical objects—ranging from the solar corona to the interstellar molecular clouds—can be explained by the specific features of relaxation in the long-range interacting systems. Here, we show that this mechanism can really work in the self-gravitating interstellar gaseous clouds; but it is irrelevant in the solar (and stellar) coronas where stratification of density is produced by the external gravitational field.

  15. The design of a long range megatransport aircraft

    NASA Technical Reports Server (NTRS)

    Weisshaar, T. A.; Layton, J. B.; Allen, C. L.

    1993-01-01

    Megatransport objectives and constraints are briefly reviewed, and certain solutions developed by student design teams at Perdue University are summarized. Particular attention is given to the market needs and the economic risks involved in such a project; and the different approaches taken to solve the problem and difficulties faced by the design teams. A long range megatransport aircraft is aimed at carrying more than 600 passengers at reduced cost, and at the same time, reducing airport and airway congestion. The design effort must take into account airport terminal facilities; passenger loading and unloading; and defeating the 'square-cube' law to design large structures.

  16. Immiscible Lattice Gas with Long-Range Interaction

    NASA Astrophysics Data System (ADS)

    Tsumaya, Akira; Ohashi, Hirotada

    We developed a new LGA model which has the applicability for simulation of immiscible two phases with wide difference in density. We introduced long-range interparticle forces into the Rothman and Keller's ILG model to represent density difference between phases. We attempted some simulations of phase separation using our new model. Two-phase interfaces are stably made with density distribution coinciding with particle color distribution. Furthermore, the two-phase interface is clearer than that obtained by the Appert and Zaleski's LG model.

  17. Fabrication and characterization of a microfluidic module for chemical gradient generation utilizing passive pumping.

    PubMed

    Kuo, Jonathan T W; Li, Connie; Meng, Ellis

    2014-01-01

    We introduce a micro-biochemical administration module (μBAM) for generating chemical gradients for use in axonal guidance studies. The device is designed to be simple to use, require minimal packaging, and be operated using only a pipette. A passive pumping mechanism is utilized to pump liquid through a SU-8 microchannel and then the micropore on the Parylene cap of the microchannel. The achievable flow rate delivery through the micropore was characterized and manipulated by varying the drop volumes used to passively drive fluid flow into the device. Biochemicals controllably delivered using this module can be combined with neuronal cell cultures to form chemical gradients for axonal guidance studies. PMID:25570971

  18. Long-range response in ac electricity grids

    NASA Astrophysics Data System (ADS)

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013), 10.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology—for example, caused by power outages or grid extensions—a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014), 10.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found.

  19. Surface tension and long range corrections of cylindrical interfaces

    SciTech Connect

    Bourasseau, E.; Ghoufi, A.

    2015-12-21

    The calculation of the surface tension of curved interfaces has been deeply investigated from molecular simulation during this last past decade. Recently, the thermodynamic Test-Area (TA) approach has been extended to the calculation of surface tension of curved interfaces. In the case of the cylindrical vapour-liquid interfaces of water and Lennard-Jones fluids, it was shown that the surface tension was independent of the curvature of the interface. In addition, the surface tension of the cylindrical interface is higher than that of the planar interface. Molecular simulations of cylindrical interfaces have been so far performed (i) by using a shifted potential, (ii) by means of large cutoff without periodic boundary conditions, or (iii) by ignoring the long range corrections to the surface tension due to the difficulty to estimate them. Indeed, unlike the planar interfaces there are no available operational expressions to consider the tail corrections to the surface tension of cylindrical interfaces. We propose here to develop the long range corrections of the surface tension for cylindrical interfaces by using the non-exponential TA (TA2) method. We also extend the formulation of the Mecke-Winkelmann corrections initially developed for planar surfaces to cylindrical interfaces. We complete this study by the calculation of the surface tension of cylindrical surfaces of liquid tin and copper using the embedded atom model potentials.

  20. Long-range response in ac electricity grids.

    PubMed

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013)EPJBFY1434-602810.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology-for example, caused by power outages or grid extensions-a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014)1951-635510.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found. PMID:27575148

  1. Slow and long-ranged dynamical heterogeneities in dissipative fluids.

    PubMed

    Avila, Karina E; Castillo, Horacio E; Vollmayr-Lee, Katharina; Zippelius, Annette

    2016-06-28

    A two-dimensional bidisperse granular fluid is shown to exhibit pronounced long-ranged dynamical heterogeneities as dynamical arrest is approached. Here we focus on the most direct approach to study these heterogeneities: we identify clusters of slow particles and determine their size, Nc, and their radius of gyration, RG. We show that , providing direct evidence that the most immobile particles arrange in fractal objects with a fractal dimension, df, that is observed to increase with packing fraction ϕ. The cluster size distribution obeys scaling, approaching an algebraic decay in the limit of structural arrest, i.e., ϕ→ϕc. Alternatively, dynamical heterogeneities are analyzed via the four-point structure factor S4(q,t) and the dynamical susceptibility χ4(t). S4(q,t) is shown to obey scaling in the full range of packing fractions, 0.6 ≤ϕ≤ 0.805, and to become increasingly long-ranged as ϕ→ϕc. Finite size scaling of χ4(t) provides a consistency check for the previously analyzed divergences of χ4(t) ∝ (ϕ-ϕc)(-γχ) and the correlation length ξ∝ (ϕ-ϕc)(-γξ). We check the robustness of our results with respect to our definition of mobility. The divergences and the scaling for ϕ→ϕc suggest a non-equilibrium glass transition which seems qualitatively independent of the coefficient of restitution. PMID:27230572

  2. Helioseismology with long-range dark matter-baryon interactions

    SciTech Connect

    Lopes, Ilídio; Panci, Paolo; Silk, Joseph E-mail: panci@iap.fr

    2014-11-10

    Assuming the existence of a primordial asymmetry in the dark sector, we study how long-range dark matter (DM)-baryon interactions, induced by the kinetic mixing of a new U(1) gauge boson and a photon, affect the evolution of the Sun and, in turn, the sound speed the profile obtained from helioseismology. Thanks to the explicit dependence on the exchanged momenta in the differential cross section (Rutherford-like scattering), we find that DM particles with a mass of ∼10 GeV, kinetic mixing parameter of the order of 10{sup –9}, and a mediator with a mass smaller than a few MeV improve the agreement between the best solar model and the helioseismic data without being excluded by direct detection experiments. In particular, the LUX detector will soon be able to either constrain or confirm our best-fit solar model in the presence of a dark sector with long-range interactions that reconcile helioseismology with thermal neutrino results.

  3. Dolphin "packet" use during long-range echolocation tasks.

    PubMed

    Finneran, James J

    2013-03-01

    When echolocating, dolphins typically emit a single broadband "click," then wait to receive the echo before emitting another click. However, previous studies have shown that during long-range echolocation tasks, they may instead emit a burst, or "packet," of several clicks, then wait for the packet of echoes to return before emitting another packet of clicks. The reasons for the use of packets are unknown. In this study, packet use was examined by having trained bottlenose dolphins perform long-range echolocation tasks. The tasks featured "phantom" echoes produced by capturing the dolphin's outgoing echolocation clicks, convolving the clicks with an impulse response to create an echo waveform, and then broadcasting the delayed, scaled echo to the dolphin. Dolphins were trained to report the presence of phantom echoes or a change in phantom echoes. Target range varied from 25 to 800 m. At ranges below 75 m, the dolphins rarely used packets. As the range increased beyond 75 m, two of the three dolphins increasingly produced packets, while the third dolphin instead utilized very high click repetition rates. The use of click packets appeared to be governed more by echo delay (target range) than echo amplitude. PMID:23464048

  4. Long Range Memory and Trends in Model Data

    NASA Astrophysics Data System (ADS)

    Oestvand, L.; Nilsen, T.; Rypdal, K.; Rypdal, M.

    2013-12-01

    Local and global observed temperature records have previously been found to have the property of long range memory (LRM). Some model data sets have also been analyzed, with various results. In this work, new model data for the Northern Hemisphere are analyzed with the wavelet variance analysis (WVA) and maximum likelihood estimation (MLE) method to look for long range memory. The data have a monthly resolution over approximately the last 2000 years. Reconstructed temperature records for the same time period seem to have an oscillation, but it is not yet decided if this oscillation is a significant trend or a natural part of an LRM record. In some of the model data used here, an oscillatory trend seems to be present, and the significance of the amplitude is tested against a null hypothesis that the data are an LRM stochastic process with no trend. In the cases where the trends are significant, the data are detrended by subtracting the estimated trend. The detrended data are then analyzed with WVA and MLE to test for LRM. The method is applied to temperature reconstructions by Mann and Moberg, for comparing the results of the model data to those of the reconstructions.

  5. The ORNL Surplus Facilities Management Program Long Range Plan

    SciTech Connect

    Myrick, T.E.

    1984-09-01

    The Surplus Facilities Management Program (SFMP) at Oak Ridge National Laboratory (ORNL) is part of the Department of Energy`s (DOE) National SFMP, administered by the Richland Operations Office. This program was established to provide for the management of DOE surplus radioactively contaminated facilities from the end of their operating life until final facility disposition is completed. As part of this program, the ORNL SFMP oversees some 76 individual surplus facilities, ranging in complexity from abandoned waste storage tanks to large experimental reactors. The ORNL SFMP has prepared this Long Range Plan to outline the long-term management strategy for those facilities included in the program. The primary objective of this plan are to: (1) develop a base of information for each ORNL SFMP facility, (2) conduct preliminary decommissioning analyses to identify feasible alternatives, (3) assess the current and future risk of each facility, (4) establish a priority list for the decommissioning projects, and (5) integrate the individual project costs and schedules into an overall program schedule and cost estimate for the ORNL site. The Long Range Plan also provides an overview of the ORNL SFMP management structure, specifies the decommissioning criteria to be employed, and identifies special technical problems, research and development needs, and special facilities and equipment that may be required for decommissioning operations.

  6. Advanced 3D imaging lidar concepts for long range sensing

    NASA Astrophysics Data System (ADS)

    Gordon, K. J.; Hiskett, P. A.; Lamb, R. A.

    2014-06-01

    Recent developments in 3D imaging lidar are presented. Long range 3D imaging using photon counting is now a possibility, offering a low-cost approach to integrated remote sensing with step changing advantages in size, weight and power compared to conventional analogue active imaging technology. We report results using a Geiger-mode array for time-of-flight, single photon counting lidar for depth profiling and determination of the shape and size of tree canopies and distributed surface reflections at a range of 9km, with 4μJ pulses with a frame rate of 100kHz using a low-cost fibre laser operating at a wavelength of λ=1.5 μm. The range resolution is less than 4cm providing very high depth resolution for target identification. This specification opens up several additional functionalities for advanced lidar, for example: absolute rangefinding and depth profiling for long range identification, optical communications, turbulence sensing and time-of-flight spectroscopy. Future concepts for 3D time-of-flight polarimetric and multispectral imaging lidar, with optical communications in a single integrated system are also proposed.

  7. Helioseismology with Long-range Dark Matter-Baryon Interactions

    NASA Astrophysics Data System (ADS)

    Lopes, Ilídio; Panci, Paolo; Silk, Joseph

    2014-11-01

    Assuming the existence of a primordial asymmetry in the dark sector, we study how long-range dark matter (DM)-baryon interactions, induced by the kinetic mixing of a new U(1) gauge boson and a photon, affect the evolution of the Sun and, in turn, the sound speed the profile obtained from helioseismology. Thanks to the explicit dependence on the exchanged momenta in the differential cross section (Rutherford-like scattering), we find that DM particles with a mass of ~10 GeV, kinetic mixing parameter of the order of 10-9, and a mediator with a mass smaller than a few MeV improve the agreement between the best solar model and the helioseismic data without being excluded by direct detection experiments. In particular, the LUX detector will soon be able to either constrain or confirm our best-fit solar model in the presence of a dark sector with long-range interactions that reconcile helioseismology with thermal neutrino results.

  8. Importance of closely spaced vertical sampling in delineating chemical and microbiological gradients in groundwater studies

    USGS Publications Warehouse

    Smith, R.L.; Harvey, R.W.; LeBlanc, D.R.

    1991-01-01

    Vertical gradients of selected chemical constituents, bacterial populations, bacterial activity and electron acceptors were investigated for an unconfined aquifer contaminated with nitrate and organic compounds on Cape Cod, Massachusetts, U.S.A. Fifteen-port multilevel sampling devices (MLS's) were installed within the contaminant plume at the source of the contamination, and at 250 and 2100 m downgradient from the source. Depth profiles of specific conductance and dissolved oxygen at the downgradient sites exhibited vertical gradients that were both steep and inversely related. Narrow zones (2-4 m thick) of high N2O and NH4+ concentrations were also detected within the contaminant plume. A 27-fold change in bacterial abundance; a 35-fold change in frequency of dividing cells (FDC), an indicator of bacterial growth; a 23-fold change in 3H-glucose uptake, a measure of heterotrophic activity; and substantial changes in overall cell morphology were evident within a 9-m vertical interval at 250 m downgradient. The existence of these gradients argues for the need for closely spaced vertical sampling in groundwater studies because small differences in the vertical placement of a well screen can lead to incorrect conclusions about the chemical and microbiological processes within an aquifer.Vertical gradients of selected chemical constituents, bacterial populations, bacterial activity and electron acceptors were investigated for an unconfined aquifer contaminated with nitrate and organic compounds on Cape Cod, Massachusetts, USA. Fifteen-port multilevel sampling devices (MLS's) were installed within the contaminant plume at the source of the contamination, and at 250 and 2100 m downgradient from the source. Depth profiles of specific conductance and dissolved oxygen at the downgradient sites exhibited vertical gradients that were both steep and inversely related. Narrow zones (2-4 m thick) of high N2O and NH4+ concentrations were also detected within the contaminant plume

  9. Atmosphere-surface exchange and long-range transport of persistent organic pollutants

    SciTech Connect

    Pul, W.A.J. van; Jaarsveld, J.A. van; Jacobs, C.M.J.

    1996-12-31

    Persistent Organic Pollutants (POPs) are compounds that are resistant to photolytic, biological and chemical degradation. Many POPs are semi-volatile at atmospheric conditions. Because of these characteristics POPs have a atmospheric lifetime of weeks or more and are subject to long-range atmospheric transport. During this transport POPs can be deposited as well as be re-emitted from soil and water bodies. In this study a model for the exchange of POP at the soil and sea surface is presented as well as its application in a long-range atmospheric transport model. The main goal of this study is to simulate the spatial distribution of POP deposition (accumulation) over Europe.

  10. Long-Range Lepton Flavor Interactions and Neutrino Oscillations

    SciTech Connect

    Davoudiasl, H.; Lee, H-S; Marciano, W.

    2011-03-31

    Recent results from the MINOS accelerator neutrino experiment suggest a possible difference between {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance oscillation parameters, which one may ascribe to a new long distance potential acting on neutrinos. As a specific example, we consider a model with gauged B - L{sub e} - 2L{sub {tau}} number which contains an extremely light new vector boson, m{sub Z}, < 10{sup -18} eV and extraordinarily weak coupling {alpha}{prime} {approx}< 10{sup -52}. In that case, differences between {nu}{sub {mu}} {yields} {nu}{sub {tau}} and {bar {nu}}{sub {mu}} {yields} {bar {nu}}{sub {tau}} oscillations can result from a long-range potential due to neutrons in the Earth and the Sun that distinguishes {nu}{sub {mu}} and {nu}{sub {tau}} on Earth, with a potential difference of {approx} 6 x 10{sup -14} eV, and changes sign for anti-neutrinos. We show that existing solar, reactor, accelerator, and atmospheric neutrino oscillation constraints can be largely accommodated for values of parameters that help explain the possible MINOS anomaly by this new physics, although there is some tension with atmospheric constraints. A long-range interaction, consistent with current bounds, could have very pronounced effects on atmospheric neutrino disappearance in the 20-50 GeV range that will be studied with the IceCube DeepCore array, currently in operation, and can have a significant effect on future high-precision long-baseline oscillation experiments which aim for {+-}1% sensitivity, in {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance, separately. Together, these experiments can extend the reach for new long-distance effects well beyond current bounds and test their relevance to the aforementioned MINOS anomaly. We also point out that long-range potentials originating from the Sun could lead to annual modulations of neutrino data at the percent level, due to the variation of the Earth-Sun distance. A similar phenomenology is shown to apply to

  11. Reservoir shore development in long range terrestrial laser scanning monitoring.

    NASA Astrophysics Data System (ADS)

    Kaczmarek, Halina

    2016-04-01

    Shore zones of reservoirs are in most cases very active, getting transformed as a result of coastal processes and mass movements initiated on the slopes surrounding the reservoir. From the point of view of the users of water reservoirs shore recession strongly undesirable as it causes destruction to infrastructure and buildings located in the immediate vicinity of the reservoir. For this reason, reservoir shores require continuous geodetic monitoring. Fast and accurate geodetic measurements covering shore sections several kilometers long, often in poorly accessible areas, are available using long range terrestrial laser scanning (TLS). The possibilities of using long range terrestrial laser scanning are shown on the example of the reservoir Jeziorsko on the Warta River (Central Poland). This reservoir, created in the years 1986-1992, is a typical retention reservoir, the annual fluctuations of which reach 5 m. Depending on the water level its surface area ranges from 42.3 to 19.6 km2. The width of the reservoir is 2.5 km. The total shore length of the reservoir, developed in Quaternary till and sand-till sediments, is 44.3 km, including 30.1 km of the unreinforced shore. Out of the unreinforced shore 27% is subject to coastal erosion. The cliff heights vary from a few cm to 12.5 meters, and the current rate of the cliff recession ranges from 0 to 1.12 m/y. The study used a terrestrial long range laser scanner Riegl VZ-4000 of a range of up to 4000 m. It enabled conducting the measurements of the cliff recession from the opposite shore of the reservoir, with an angular resolution of 0.002°, which gives about 50 measurement points per 1 m2. The measurements were carried out in the years 2014-2015, twice a year, in early spring before high water level, and in late autumn at a dropping water level. This allowed the separation of the impact of coastal processes and frost weathering on the cliff recession and their quantitative determination. The size and nature of

  12. Transuranic waste projections at SRS for long range planning

    SciTech Connect

    Hootman, H.E.; Cook, J.R.

    1994-05-01

    This report predicts 30 year receipts of solid transuranic (TRU) wastes from eventual plutonium facility deactivation and cleanup, and combines them with the existing TRU waste holdings to provide a technical and quantitative basis for interim and long range TRU waste management planning. The current TRU waste holdings have been characterized based on data from the Computerized Radioactive Waste Burial Records Analysis (COBRA) system. Six TRU waste disposition categories have been identified for existing TRU waste as shown in Table 1. An additional category has been quantified that includes projected waste volumes from the Decontamination and Decommissioning (D&D) of TRU waste generating facilities. These projections are based on COBRA data from D&D of the original plutonium finishing facilities in F and H Areas that were replaced in the 1970`s and 80`s.

  13. Long-range properties of 1 S bottomonium states

    NASA Astrophysics Data System (ADS)

    Brambilla, Nora; Krein, Gastão; Tarrús Castellà, Jaume; Vairo, Antonio

    2016-03-01

    In the framework of weakly coupled potential nonrelativistic QCD, we derive, first, an analytical expression for the chromopolarizability of 1 S bottomonium states in agreement with previous determinations. Then we use the QCD trace anomaly to obtain the two-pion production amplitude for the chromopolarizability operator and match the result to a chiral effective field theory with 1 S bottomonium states and pions as degrees of freedom. In this chiral effective field theory we compute some long-range properties of the 1 S bottomonium generated by the pion coupling such as the leading chiral logarithm to the 1 S bottomonium mass and the van der Waals potential between two 1 S bottomonium states. Both results improve on previously known expressions.

  14. Sparse Labeling of Proteins: Structural Characterization from Long Range Constraints

    PubMed Central

    Prestegard, James H.; Agard, David A.; Moremen, Kelley W.; Lavery, Laura A.; Morris, Laura C.; Pederson, Kari

    2014-01-01

    Structural characterization of biologically important proteins faces many challenges associated with degradation of resolution as molecular size increases and loss of resolution improving tools such as perdeuteration when non-bacterial hosts must be used for expression. In these cases, sparse isotopic labeling (single or small subsets of amino acids) combined with long range paramagnetic constraints and improved computational modeling offer an alternative. This perspective provides a brief overview of this approach and two discussions of potential applications; one involving a very large system (an Hsp90 homolog) in which perdeuteration is possible and methyl-TROSY sequences can potentially be used to improve resolution, and one involving ligand placement in a glycosylated protein where resolution is achieved by single amino acid labeling (the sialyltransferase, ST6Gal1). This is not intended as a comprehensive review, but as a discussion of future prospects that promise impact on important questions in the structural biology area. PMID:24656078

  15. Sparse labeling of proteins: Structural characterization from long range constraints

    NASA Astrophysics Data System (ADS)

    Prestegard, James H.; Agard, David A.; Moremen, Kelley W.; Lavery, Laura A.; Morris, Laura C.; Pederson, Kari

    2014-04-01

    Structural characterization of biologically important proteins faces many challenges associated with degradation of resolution as molecular size increases and loss of resolution improving tools such as perdeuteration when non-bacterial hosts must be used for expression. In these cases, sparse isotopic labeling (single or small subsets of amino acids) combined with long range paramagnetic constraints and improved computational modeling offer an alternative. This perspective provides a brief overview of this approach and two discussions of potential applications; one involving a very large system (an Hsp90 homolog) in which perdeuteration is possible and methyl-TROSY sequences can potentially be used to improve resolution, and one involving ligand placement in a glycosylated protein where resolution is achieved by single amino acid labeling (the sialyltransferase, ST6Gal1). This is not intended as a comprehensive review, but as a discussion of future prospects that promise impact on important questions in the structural biology area.

  16. Superconductivity from a Long-Range Repulsive Interaction

    NASA Astrophysics Data System (ADS)

    Onari, S.; Arita, R.; Kuroki, K.; Aoki, H.

    2006-09-01

    The lattice model with short-range interactions (exemplified by the Hubbard model) is known to exhibit quite different features from those in the electron gas with the long-range Coulomb interaction. In order to explore how they cross over to each other, we have studied an extended Hubbard model which includes repulsions up to the 12th neighbors with the simplified fluctuation exchange (FLEX) approximation for the square lattice. We have found that (i) in the most dilute density region, spin and charge fluctuations become comparable, and s- and p-waves superconductivity become dominant, in agreement with the result for the electron gas by Takada, while (ii) the dominant spin fluctuation and its reflection on dx2-y2 and dxy pairing, both the effect of lattice structure, persists well away (n ≳ 0.2) from the half filling. 2006 American Institute of Physics

  17. Phantom energy mediates a long-range repulsive force.

    PubMed

    Amendola, Luca

    2004-10-29

    Scalar field models with nonstandard kinetic terms have been proposed in the context of k inflation, of Born-Infeld Lagrangians, of phantom energy and, more in general, of low-energy string theory. In general, scalar fields are expected to couple to matter inducing a new interaction. In this Letter I derive the cosmological perturbation equations and the Yukawa correction to gravity for such general models. I find three interesting results: first, when the field behaves as phantom energy (equation of state less than -1), then the coupling strength is negative, inducing a long-range repulsive force; second, the dark-energy field might cluster on astrophysical scales; third, applying the formalism to a Brans-Dicke theory with a general kinetic term it is shown that its Newtonian effects depend on a single parameter that generalizes the Brans-Dicke constant. PMID:15525149

  18. Parallelized Stochastic Cutoff Method for Long-Range Interacting Systems

    NASA Astrophysics Data System (ADS)

    Endo, Eishin; Toga, Yuta; Sasaki, Munetaka

    2015-07-01

    We present a method of parallelizing the stochastic cutoff (SCO) method, which is a Monte-Carlo method for long-range interacting systems. After interactions are eliminated by the SCO method, we subdivide a lattice into noninteracting interpenetrating sublattices. This subdivision enables us to parallelize the Monte-Carlo calculation in the SCO method. Such subdivision is found by numerically solving the vertex coloring of a graph created by the SCO method. We use an algorithm proposed by Kuhn and Wattenhofer to solve the vertex coloring by parallel computation. This method was applied to a two-dimensional magnetic dipolar system on an L × L square lattice to examine its parallelization efficiency. The result showed that, in the case of L = 2304, the speed of computation increased about 102 times by parallel computation with 288 processors.

  19. A long-range polarization-controlled optical tractor beam

    NASA Astrophysics Data System (ADS)

    Shvedov, Vladlen; Davoyan, Arthur R.; Hnatovsky, Cyril; Engheta, Nader; Krolikowski, Wieslaw

    2014-11-01

    The laser beam has become an indispensable tool for the controllable manipulation and transport of microscopic objects in biology, physical chemistry and condensed matter physics. In particular, ‘tractor’ laser beams can draw matter towards a laser source and perform, for instance, all-optical remote sampling. Recent advances in lightwave technology have already led to small-scale experimental demonstrations of tractor beams. However, the realization of long-range tractor beams has not gone beyond the realm of theoretical investigations. Here, we demonstrate the stable transfer of gold-coated hollow glass spheres against the power flow of a single inhomogeneously polarized laser beam over tens of centimetres. Additionally, by varying the polarization state of the beam we can stop the spheres or reverse the direction of their motion at will.

  20. Modeling of long range frequency sweeping for energetic particle modes

    SciTech Connect

    Nyqvist, R. M.; Breizman, B. N.

    2013-04-15

    Long range frequency sweeping events are simulated numerically within a one-dimensional, electrostatic bump-on-tail model with fast particle sources and collisions. The numerical solution accounts for fast particle trapping and detrapping in an evolving wave field with a fixed wavelength, and it includes three distinct collisions operators: Drag (dynamical friction on the background electrons), Krook-type collisions, and velocity space diffusion. The effects of particle trapping and diffusion on the evolution of holes and clumps are investigated, and the occurrence of non-monotonic (hooked) frequency sweeping and asymptotically steady holes is discussed. The presented solution constitutes a step towards predictive modeling of frequency sweeping events in more realistic geometries.

  1. Chromatin and epigenetic features of long-range gene regulation

    PubMed Central

    Harmston, Nathan; Lenhard, Boris

    2013-01-01

    The precise regulation of gene transcription during metazoan development is controlled by a complex system of interactions between transcription factors, histone modifications and modifying enzymes and chromatin conformation. Developments in chromosome conformation capture technologies have revealed that interactions between regions of chromatin are pervasive and highly cell-type specific. The movement of enhancers and promoters in and out of higher-order chromatin structures within the nucleus are associated with changes in expression and histone modifications. However, the factors responsible for mediating these changes and determining enhancer:promoter specificity are still not completely known. In this review, we summarize what is known about the patterns of epigenetic and chromatin features characteristic of elements involved in long-range interactions. In addition, we review the insights into both local and global patterns of chromatin interactions that have been revealed by the latest experimental and computational methods. PMID:23766291

  2. Protein lethality investigated in terms of long range dynamical interactions.

    PubMed

    Rodrigues, Francisco A; Costa, Luciano da Fontoura

    2009-04-01

    The relationship between network structure/dynamics and biological function constitutes a fundamental issue in systems biology. However, despite many related investigations, the correspondence between structure and biological functions is not yet fully understood. A related subject that has deserved particular attention recently concerns how essentiality is related to the structure and dynamics of protein interactions. In the current work, protein essentiality is investigated in terms of long range influences in protein-protein interaction networks by considering simulated dynamical aspects. This analysis is performed with respect to outward activations, an approach which models the propagation of interactions between proteins by considering self-avoiding random walks. The obtained results are compared to protein local connectivity. Both the connectivity and the outward activations were found to be strongly related to protein essentiality. PMID:19396375

  3. Fractional dynamics of coupled oscillators with long-range interaction

    SciTech Connect

    Tarasov, Vasily E.; Zaslavsky, George M.

    2006-06-15

    We consider a one-dimensional chain of coupled linear and nonlinear oscillators with long-range powerwise interaction. The corresponding term in dynamical equations is proportional to 1/|n-m|{sup {alpha}}{sup +1}. It is shown that the equation of motion in the infrared limit can be transformed into the medium equation with the Riesz fractional derivative of order {alpha}, when 0<{alpha}<2. We consider a few models of coupled oscillators and show how their synchronization can appear as a result of bifurcation, and how the corresponding solutions depend on {alpha}. The presence of a fractional derivative also leads to the occurrence of localized structures. Particular solutions for fractional time-dependent complex Ginzburg-Landau (or nonlinear Schroedinger) equation are derived. These solutions are interpreted as synchronized states and localized structures of the oscillatory medium.

  4. Position-insensitive long range inductive power transfer

    NASA Astrophysics Data System (ADS)

    Kwan, Christopher H.; Lawson, James; Yates, David C.; Mitcheson, Paul D.

    2014-11-01

    This paper presents results of an improved inductive wireless power transfer system for reliable long range powering of sensors with milliwatt-level consumption. An ultra-low power flyback impedance emulator operating in open loop is used to present the optimal load to the receiver's resonant tank. Transmitter power modulation is implemented in order to maintain constant receiver power and to prevent damage to the receiver electronics caused by excessive received voltage. Received power is steady up to 3 m at around 30 mW. The receiver electronics and feedback system consumes 3.1 mW and so with a transmitter input power of 163.3 W the receiver becomes power neutral at 4.75 m. Such an IPT system can provide a reliable alternative to energy harvesters for supplying power concurrently to multiple remote sensors.

  5. Long-Range Spin Transfer in Triple Quantum Dots

    NASA Astrophysics Data System (ADS)

    Sánchez, R.; Granger, G.; Gaudreau, L.; Kam, A.; Pioro-Ladrière, M.; Studenikin, S. A.; Zawadzki, P.; Sachrajda, A. S.; Platero, G.

    2014-05-01

    Tunneling in a quantum coherent structure is not restricted to only nearest neighbors. Hopping between distant sites is possible via the virtual occupation of otherwise avoided intermediate states. Here we report the observation of long-range transitions in the transport through three quantum dots coupled in series. A single electron is delocalized between the left and right quantum dots, while the center one remains always empty. Superpositions are formed, and both charge and spin are exchanged between the outermost dots. The delocalized electron acts as a quantum bus transferring the spin state from one end to the other. Spin selection is enabled by spin correlations. The process is detected via the observation of narrow resonances which are insensitive to Pauli spin blockade.

  6. Long-range spin transfer in triple quantum dots.

    PubMed

    Sánchez, R; Granger, G; Gaudreau, L; Kam, A; Pioro-Ladrière, M; Studenikin, S A; Zawadzki, P; Sachrajda, A S; Platero, G

    2014-05-01

    Tunneling in a quantum coherent structure is not restricted to only nearest neighbors. Hopping between distant sites is possible via the virtual occupation of otherwise avoided intermediate states. Here we report the observation of long-range transitions in the transport through three quantum dots coupled in series. A single electron is delocalized between the left and right quantum dots, while the center one remains always empty. Superpositions are formed, and both charge and spin are exchanged between the outermost dots. The delocalized electron acts as a quantum bus transferring the spin state from one end to the other. Spin selection is enabled by spin correlations. The process is detected via the observation of narrow resonances which are insensitive to Pauli spin blockade. PMID:24836266

  7. Disrupting long-range polar order with an electric field

    NASA Astrophysics Data System (ADS)

    Guo, Hanzheng; Liu, Xiaoming; Xue, Fei; Chen, Long-Qing; Hong, Wei; Tan, Xiaoli

    2016-05-01

    Electric fields are known to favor long-range polar order through the aligning of electric dipoles in relation to Coulomb's force. Therefore, it would be surprising to observe a disordered polar state induced from an ordered state by electric fields. Here we show such an unusual phenomenon in a polycrystalline oxide where electric fields induce a ferroelectric-to-relaxor phase transition. The nonergodic relaxor phase with disordered dipoles appears as an intermediate state under electric fields during polarization reversal of the ferroelectric phase. Using the phenomenological theory, the underlying mechanism for this unexpected behavior can be attributed to the slow kinetics of the ferroelectric-to-relaxor phase transition, as well as its competition against domain switching during electric reversal. The demonstrated material could also serve as a model system to study the transient stages in first-order phase transitions; the slow kinetics does not require the use of sophisticated ultrafast tools.

  8. Long-Range Correlations of Global Sea Surface Temperature.

    PubMed

    Jiang, Lei; Zhao, Xia; Wang, Lu

    2016-01-01

    Scaling behaviors of the global monthly sea surface temperature (SST) derived from 1870-2009 average monthly data sets of Hadley Centre Sea Ice and SST (HadISST) are investigated employing detrended fluctuation analysis (DFA). The global SST fluctuations are found to be strong positively long-range correlated at all pertinent time-intervals. The value of scaling exponent is larger in the tropics than those in the intermediate latitudes of the northern and southern hemispheres. DFA leads to the scaling exponent α = 0.87 over the globe (60°S~60°N), northern hemisphere (0°N~60°N), and southern hemisphere (0°S~60°S), α = 0.84 over the intermediate latitude of southern hemisphere (30°S~60°S), α = 0.81 over the intermediate latitude of northern hemisphere (30°N~60°N) and α = 0.90 over the tropics 30°S~30°N [fluctuation F(s) ~ sα], which the fluctuations of monthly SST anomaly display long-term correlated behaviors. Furthermore, the larger the standard deviation is, the smaller long-range correlations (LRCs) of SST in the corresponding regions, especially in three distinct upwelling areas. After the standard deviation is taken into account, an index χ = α * σ is introduced to obtain the spatial distributions of χ. There exists an obvious change of global SST in central east and northern Pacific and the northwest Atlantic. This may be as a clue on predictability of climate and ocean variabilities. PMID:27100397

  9. Long-Range Correlations of Global Sea Surface Temperature

    PubMed Central

    Jiang, Lei; Zhao, Xia; Wang, Lu

    2016-01-01

    Scaling behaviors of the global monthly sea surface temperature (SST) derived from 1870–2009 average monthly data sets of Hadley Centre Sea Ice and SST (HadISST) are investigated employing detrended fluctuation analysis (DFA). The global SST fluctuations are found to be strong positively long-range correlated at all pertinent time-intervals. The value of scaling exponent is larger in the tropics than those in the intermediate latitudes of the northern and southern hemispheres. DFA leads to the scaling exponent α = 0.87 over the globe (60°S~60°N), northern hemisphere (0°N~60°N), and southern hemisphere (0°S~60°S), α = 0.84 over the intermediate latitude of southern hemisphere (30°S~60°S), α = 0.81 over the intermediate latitude of northern hemisphere (30°N~60°N) and α = 0.90 over the tropics 30°S~30°N [fluctuation F(s) ~ sα], which the fluctuations of monthly SST anomaly display long-term correlated behaviors. Furthermore, the larger the standard deviation is, the smaller long-range correlations (LRCs) of SST in the corresponding regions, especially in three distinct upwelling areas. After the standard deviation is taken into account, an index χ = α * σ is introduced to obtain the spatial distributions of χ. There exists an obvious change of global SST in central east and northern Pacific and the northwest Atlantic. This may be as a clue on predictability of climate and ocean variabilities. PMID:27100397

  10. Long-range energy transport in photosystem II

    NASA Astrophysics Data System (ADS)

    Roden, Jan J. J.; Bennett, Doran I. G.; Whaley, K. Birgitta

    2016-06-01

    We simulate the long-range inter-complex electronic energy transfer in photosystem II - from the antenna complex, via a core complex, to the reaction center - using a non-Markovian (ZOFE) quantum master equation description that allows the electronic coherence involved in the energy transfer to be explicitly included at all length scales. This allows us to identify all locations where coherence is manifested and to further identify the pathways of the energy transfer in the full network of coupled chromophores using a description based on excitation probability currents. We investigate how the energy transfer depends on the initial excitation - localized, coherent initial excitation versus delocalized, incoherent initial excitation - and find that the overall energy transfer is remarkably robust with respect to such strong variations of the initial condition. To explore the importance of vibrationally enhanced transfer and to address the question of optimization in the system parameters, we systematically vary the strength of the coupling between the electronic and the vibrational degrees of freedom. We find that the natural parameters lie in a (broad) region that enables optimal transfer efficiency and that the overall long-range energy transfer on a ns time scale appears to be very robust with respect to variations in the vibronic coupling of up to an order of magnitude. Nevertheless, vibrationally enhanced transfer appears to be crucial to obtain a high transfer efficiency, with the latter falling sharply for couplings outside the optimal range. Comparison of our full quantum simulations to results obtained with a "classical" rate equation based on a modified-Redfield/generalized-Förster description previously used to simulate energy transfer dynamics in the entire photosystem II complex shows good agreement for the overall time scales of excitation energy transport.

  11. Photoassociation of long-range nD Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Raithel, Georg

    2015-05-01

    Cold atomic systems have opened new frontiers at the interface of atomic and molecular physics. Of particular interest are a recently discovered class of long-range, homonuclear Rydberg molecules first predicted in and observed in. In rubidium, these molecules are formed via low-energy electron scattering of the Rydberg electron from a 5S1/2 ground-state atom that is present within the Rydberg atom's volume. The binding mostly arises from S-wave and P-wave triplet scattering. In recent work, we have observed long-range homonuclear diatomic nD Rydberg molecules photoassociated out of an ultracold gas of 87Rb atoms for principal quantum numbers 34 <= n <= 40. Related results have also been reported in. The measured ground-state binding energies of 87Rb(nD + 5S1 / 2) molecular states are larger than those of their 87Rb(nS + 5S1 / 2) counterparts, showing the dependence of the molecular bond on the angular momentum of the Rydberg atom. We have exhibited the transition of 87Rb(nD + 5S1 / 2) molecules from a molecular-binding-dominant regime at low n to a fine-structure-dominant regime at high n [akin to Hund's cases (a) and (c), respectively]. In our analysis, we use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom. The hyperfine structure is important because it gives rise to mixed singlet-triplet potentials. This work was supported by the AFOSR (FA9550-10-1-0453) and the NSF (PHY-1205559).

  12. Bacteria are not too small for spatial sensing of chemical gradients: An experimental evidence

    PubMed Central

    Thar, Roland; Kühl, Michael

    2003-01-01

    By analyzing the chemotactic behavior of a recently described marine bacterial species, we provide experimental evidence that bacteria are not too small for sensing chemical gradients spatially. The bipolar flagellated vibrioid bacteria (typical size 2 × 6 μm) exhibit a unique motility pattern as they translate along as well as rotate around their short axis, i.e., the pathways of the cell poles describe a double helix. The natural habitat of the bacteria is characterized by steep oxygen gradients where they accumulate in a band at their preferred oxygen concentration of ≈2 μM. Single cells leaving the band toward the oxic region typically return to the band within 16 s following a U-shaped track. A detailed analysis of the tracks reveals that the cells must be able to sense the oxygen gradient perpendicular to their swimming direction. Thus, they can detect oxygen gradients along a distance of ≈5 μm corresponding to the extension of their long axis. The observed behavior can be explained by the presence of two independent sensor regions at either cell pole that modulate the rotation speed of the polar flagellar bundles, i.e., the flagellar bundle at the cell pole exposed to higher oxygen concentration is rotating faster than the other bundle. A mathematical model based on these assumptions reproduces the observed swimming behavior of the bacteria. PMID:12719518

  13. Meteorological effects on long-range outdoor sound propagation

    NASA Technical Reports Server (NTRS)

    Klug, Helmut

    1990-01-01

    Measurements of sound propagation over distances up to 1000 m were carried out with an impulse sound source offering reproducible, short time signals. Temperature and wind speed at several heights were monitored simultaneously; the meteorological data are used to determine the sound speed gradients according to the Monin-Obukhov similarity theory. The sound speed profile is compared to a corresponding prediction, gained through the measured travel time difference between direct and ground reflected pulse (which depends on the sound speed gradient). Positive sound speed gradients cause bending of the sound rays towards the ground yielding enhanced sound pressure levels. The measured meteorological effects on sound propagation are discussed and illustrated by ray tracing methods.

  14. Multicomponent diffusion under general chemical potential gradients. Final report, July 1, 1981-June 30, 1984

    SciTech Connect

    Sato, H.; Kikuchi, R.

    1984-06-01

    Theoretical basis for identifying the origin of deterioration of high temperature materials by diffusion has been sought. The need for an appropriate form of irreversible statistical mechanics, rather than commonly utilized irreversible thermodynamics, to this problem was identified. The Path Probability method of irreversible statistical mechanics was thus adapted to diffusion problems and necessary modifications of the method suitable for transport problems in multicomponent systems were made. Thermal diffusion (diffusion which occurs under temperature gradient) was then formulated by the Path Probability method for the first time, and so far elusive concepts such as the heat of transport were thus microscopically identified. An example of demixing of originally homogeneous solid solutions under general chemical potential gradients was thus worked out.

  15. In-flight sleep, pilot fatigue and Psychomotor Vigilance Task performance on ultra-long range versus long range flights.

    PubMed

    Gander, Philippa H; Signal, T Leigh; van den Berg, Margo J; Mulrine, Hannah M; Jay, Sarah M; Jim Mangie, Captain

    2013-12-01

    This study evaluated whether pilot fatigue was greater on ultra-long range (ULR) trips (flights >16 h on 10% of trips in a 90-day period) than on long range (LR) trips. The within-subjects design controlled for crew complement, pattern of in-flight breaks, flight direction and departure time. Thirty male Captains (mean age = 54.5 years) and 40 male First officers (mean age = 48.0 years) were monitored on commercial passenger flights (Boeing 777 aircraft). Sleep was monitored (actigraphy, duty/sleep diaries) from 3 days before the first study trip to 3 days after the second study trip. Karolinska Sleepiness Scale, Samn-Perelli fatigue ratings and a 5-min Psychomotor Vigilance Task were completed before, during and after every flight. Total sleep in the 24 h before outbound flights and before inbound flights after 2-day layovers was comparable for ULR and LR flights. All pilots slept on all flights. For each additional hour of flight time, they obtained an estimated additional 12.3 min of sleep. Estimated mean total sleep was longer on ULR flights (3 h 53 min) than LR flights (3 h 15 min; P(F) = 0.0004). Sleepiness ratings were lower and mean reaction speed was faster at the end of ULR flights. Findings suggest that additional in-flight sleep mitigated fatigue effectively on longer flights. Further research is needed to clarify the contributions to fatigue of in-flight sleep versus time awake at top of descent. The study design was limited to eastward outbound flights with two Captains and two First Officers. Caution must be exercised when extrapolating to different operations. PMID:23889686

  16. Describing long-range charge-separation processes with subsystem density-functional theory

    SciTech Connect

    Solovyeva, Alisa; Neugebauer, Johannes; Pavanello, Michele

    2014-04-28

    Long-range charge-transfer processes in extended systems are difficult to describe with quantum chemical methods. In particular, cost-effective (non-hybrid) approximations within time-dependent density functional theory (DFT) are not applicable unless special precautions are taken. Here, we show that the efficient subsystem DFT can be employed as a constrained DFT variant to describe the energetics of long-range charge-separation processes. A formal analysis of the energy components in subsystem DFT for such excitation energies is presented, which demonstrates that both the distance dependence and the long-range limit are correctly described. In addition, electronic couplings for these processes as needed for rate constants in Marcus theory can be obtained from this method. It is shown that the electronic structure of charge-separated states constructed by a positively charged subsystem interacting with a negatively charged one is difficult to converge — charge leaking from the negative subsystem to the positive one can occur. This problem is related to the delocalization error in DFT and can be overcome with asymptotically correct exchange–correlation (XC) potentials or XC potentials including a sufficiently large amount of exact exchange. We also outline an approximate way to obtain charge-transfer couplings between locally excited and charge-separated states.

  17. Neural network analysis of long-range precipitation forecasts

    NASA Astrophysics Data System (ADS)

    Silverman, David I.

    The object of this research is to show that long range forecasts of precipitation for California is possible using large-scale climatological indexes and that artificial neural networks (ANNs) are a viable tool for modeling and data extraction. For each of California's seven climate zones, ANNs were trained using a calendar year's input of parameters to predict the coming water year's total precipitation and to predict the following water year's. Activity by the El Niño-Southern Oscillation (ENSO) in the east Pacific and the 700 mb height anomaly over the northern hemisphere is known to be related to various phenomena in specific regions of California. These large-scale climatological parameters represent the global atmospheric circulation that, in a sense, bring the weather to a region. By determining how these parameters interact over time, we can determine the general weather conditions that will arrive in a region. Because of the large amount of data, the short time period the data covers, the unknown type of relationships involved, and the possibly extraneous data, common statistical methods are not easily applied. Artificial neural networks (ANNs) are powerful and useful tools, especially in cases where the complex relationship between the inputs and outputs cannot easily be determined by common modeling methods. 0It was found that the pattern of rainfall predicted by the ANN model matched closely the observed rainfall with the nine month time lag for most California climate zones and for most years. This portion of the research shows the possibility of making long range forecasts using ANNs and large scale climatological parameters. These artificial ``brains'' were then analyzed by two different methods to reveal their methods of forecasting. One method produced for each climate zone a reduced set of important global parameters that were used in a simple linear regression model with good results. The second method gave information about how the individual

  18. ORNL long-range environmental and waste management plan

    SciTech Connect

    Baldwin, J.S.; Bates, L.D.; Brown, C.H.; Easterday, C.A.; Hill, L.G.; Kendrick, C.M.; McNeese, L.E.; Myrick, T.E.; Payne, T.L.; Pepper, C.E.; Robinson, S.M.; Rohwer, P.S.; Scanlan, T.F.; Smith, M.A.; Stratton, L.E.; Trabalka, J.R.

    1989-09-01

    This report, the ORNL Long-Range Environmental and Waste Management Plan, is the annual update in a series begun in fiscal year 1985. Its primary purpose is to provide a thorough and systematic planning document to reflect the continuing process of site assessment, strategy development, and planning for the current and long-term control of environmental issues, waste management practices, and remedial action requirements. The document also provides an estimate of the resources required to implement the current plan. This document is not intended to be a budget document; it is, however, intended to provide guidance to both Martin Marietta Energy Systems, Inc., and the US Department of Energy (DOE) management as to the near order of magnitude of the resources (primarily funding requirements) and the time frame required to execute the strategy in the present revision of the plan. As with any document of this nature, the near-term (one to three years) part of the plan is a pragmatic assessment of the current program and ongoing capital projects and reflects the efforts perceived to be necessary to comply with all current state and federal regulations and DOE orders. It also should be in general agreement with current budget (funding) requests and obligations for these immediate years. 55 figs., 72 tabs.

  19. Long-range magnetic coupling across a polar insulating layer

    PubMed Central

    Lü, W. M.; Saha, Surajit; Wang, X. Renshaw; Liu, Z. Q.; Gopinadhan, K.; Annadi, A.; Zeng, S. W.; Huang, Z.; Bao, B. C.; Cong, C. X.; Venkatesan, M.; Yu, T.; Coey, J. M. D.; Ariando; Venkatesan, T.

    2016-01-01

    Magnetic interactions in solids are normally mediated by short-range exchange or weak dipole fields. Here we report a magnetic interaction that can propagate over long distances (∼10 nm) across a polar insulating oxide spacer. Evidence includes oscillations of magnetization, coercivity and field-cooled loop shift with the thickness of LaAlO3 in La0.67Sr0.33MnO3/LaAlO3/SrTiO3 heterostructures. Similar modifications of the hysteresis loop appear when two coupled films of La0.67Sr0.33MnO3 are separated by LaAlO3, or another polar insulator, but they are absent when the oxide spacer layer is nonpolar. The loop shift is attributed to strong spin–orbit coupling and Dzyaloshinskii–Moriya interaction at the interfaces. There is evidence from inelastic light scattering that the polar spacer mediates long-range transmission of orbital magnetization. This coupling mechanism is expected to apply for any conducting ferromagnetic oxide with mixed valence; in view of electron hopping frequency involved, it raises the prospect of terahertz tunability of magnetic coupling. PMID:26980456

  20. Two general models that generate long range correlation

    NASA Astrophysics Data System (ADS)

    Gan, Xiaocong; Han, Zhangang

    2012-06-01

    In this paper we study two models that generate sequences with LRC (long range correlation). For the IFT (inverse Fourier transform) model, our conclusion is the low frequency part leads to LRC, while the high frequency part tends to eliminate it. Therefore, a typical method to generate a sequence with LRC is multiplying the spectrum of a white noise sequence by a decaying function. A special case is analyzed: the linear combination of a smooth curve and a white noise sequence, in which the DFA plot consists of two line segments. For the patch model, our conclusion is long subsequences leads to LRC, while short subsequences tend to eliminate it. Therefore, we can generate a sequence with LRC by using a fat-tailed PDF (probability distribution function) of the length of the subsequences. A special case is also analyzed: if a patch model with long subsequences is mixed with a white noise sequence, the DFA plot will consist of two line segments. We have checked known models and actual data, and found they are all consistent with this study.

  1. Long range metrological atomic force microscope with versatile measuring head

    NASA Astrophysics Data System (ADS)

    Lu, Mingzhen; Gao, Sitian; Li, Qi; Li, Wei; Shi, Yushu; Tao, Xingfu

    2013-01-01

    A long range metrological atomic force microscope (AFM) has been developed at NIM. It aims to realize a maximum measurement volume of 50mm×50mm×2mm with an uncertainty of a few tens of nanometers in the whole range. In compliance with Abbe Principle, the instrument is designed as a sample-scanning type. The sample is moved by a 6-DOF piezostage in combination with a hybrid slide-air bearing stage for long scanning range. Homodyne interferometers with four passes attached to a metrological frame measure relative displacement between the probe and sample thus the instrument is directly traceable to the SI. An AFM head is developed as the measuring head for the instrument. Considering accuracy and dynamic performance of the instrument, it is designed to be capable of scanning perpendicularly in a range of 5μm×5μm×5μm with a 3-DOF piezostage. Optical beam deflection method is used and a minimum of components are mounted on the moving part. A novel design is devised so that the photodetector is only sensitive to the deflection of cantilever, but not the displacement of the head. Moving manner of the head varies with scanning range and mode of the instrument. Results of different measurements are demonstrated, showing the excellent performance of the instrument.

  2. Stochastic Kinetic Monte Carlo algorithms for long-range Hamiltonians

    SciTech Connect

    Mason, D R; Rudd, R E; Sutton, A P

    2003-10-13

    We present a higher order kinetic Monte Carlo methodology suitable to model the evolution of systems in which the transition rates are non- trivial to calculate or in which Monte Carlo moves are likely to be non- productive flicker events. The second order residence time algorithm first introduced by Athenes et al.[1] is rederived from the n-fold way algorithm of Bortz et al.[2] as a fully stochastic algorithm. The second order algorithm can be dynamically called when necessary to eliminate unproductive flickering between a metastable state and its neighbors. An algorithm combining elements of the first order and second order methods is shown to be more efficient, in terms of the number of rate calculations, than the first order or second order methods alone while remaining statistically identical. This efficiency is of prime importance when dealing with computationally expensive rate functions such as those arising from long- range Hamiltonians. Our algorithm has been developed for use when considering simulations of vacancy diffusion under the influence of elastic stress fields. We demonstrate the improved efficiency of the method over that of the n-fold way in simulations of vacancy diffusion in alloys. Our algorithm is seen to be an order of magnitude more efficient than the n-fold way in these simulations. We show that when magnesium is added to an Al-2at.%Cu alloy, this has the effect of trapping vacancies. When trapping occurs, we see that our algorithm performs thousands of events for each rate calculation performed.

  3. Long-range magnetic coupling across a polar insulating layer.

    PubMed

    Lü, W M; Saha, Surajit; Wang, X Renshaw; Liu, Z Q; Gopinadhan, K; Annadi, A; Zeng, S W; Huang, Z; Bao, B C; Cong, C X; Venkatesan, M; Yu, T; Coey, J M D; Ariando; Venkatesan, T

    2016-01-01

    Magnetic interactions in solids are normally mediated by short-range exchange or weak dipole fields. Here we report a magnetic interaction that can propagate over long distances (∼10 nm) across a polar insulating oxide spacer. Evidence includes oscillations of magnetization, coercivity and field-cooled loop shift with the thickness of LaAlO3 in La0.67Sr0.33MnO3/LaAlO3/SrTiO3 heterostructures. Similar modifications of the hysteresis loop appear when two coupled films of La0.67Sr0.33MnO3 are separated by LaAlO3, or another polar insulator, but they are absent when the oxide spacer layer is nonpolar. The loop shift is attributed to strong spin-orbit coupling and Dzyaloshinskii-Moriya interaction at the interfaces. There is evidence from inelastic light scattering that the polar spacer mediates long-range transmission of orbital magnetization. This coupling mechanism is expected to apply for any conducting ferromagnetic oxide with mixed valence; in view of electron hopping frequency involved, it raises the prospect of terahertz tunability of magnetic coupling. PMID:26980456

  4. Long Range Chiral Imprinting of Cu(110) by Tartaric Acid

    SciTech Connect

    Lawton, T J; Pushkarev, V; Wei, D; Lucci, F R; Sholl, D S; Gellman, A J; Sykes, E C. H.

    2013-10-31

    Restructuring of metals by chiral molecules represents an important route to inducing and controlling enantioselective surface chemistry. Tartaric acid adsorption on Cu(110) has served as a useful system for understanding many aspects of chiral molecule adsorption and ordering on a metal surface, and a number of chiral and achiral unit cells have been reported. Herein, we show that given the appropriate annealing treatment, singly deprotonated tartaric acid monolayers can restructure the Cu metal itself, and that the resulting structure is both highly ordered and chiral. Molecular resolution scanning tunneling microscopy reveals that singly deprotonated tartaric acid extracts Cu atoms from the Cu(110) surface layer and incorporates them into highly ordered, chiral adatom arrays capped by a continuous molecular layer. Further evidence for surface restructuring comes from images of atom-deep trenches formed in the Cu(110) surface during the process. These trenches also run in low symmetry directions and are themselves chiral. Simulated scanning tunneling microscopy images are consistent with the appearance of the added atom rows and etched trenches. The chiral imprinting results in a long-range, highly ordered unit cell covering the whole surface as confirmed by low energy electron diffraction. Details of the restructuring mechanism were further investigated via time-lapse imaging at elevated temperature. This work reveals the stages of nanoscale surface restructuring and offers an interesting method for chiral modification of an achiral metal surface.

  5. Ultracold Long-Range Rydberg Molecules with Complex Multichannel Spectra

    NASA Astrophysics Data System (ADS)

    Eiles, Matthew; Greene, Chris

    2016-05-01

    A generalized class of exotic long-range Rydberg molecules consisting of a multichannel Rydberg atom bound to a distant ground state atom by the Rydberg electron is predicted. These molecules are characterized by the rich physics provided by the strongly perturbed multichannel Rydberg spectra of divalent atoms, in contrast to the regular Rydberg series of the alkali atoms used to form Rydberg molecules to date. These multichannel Rydberg molecules exhibit favorable properties for laser excitation, because states exist where the quantum defect varies strongly with the principal quantum number n. In particular, the nd Rydberg state of calcium becomes nearly degenerate with states of high orbital angular momentum over the range 17 < n < 22 , promoting its admixture into the high l deeply bound ``trilobite'' molecule states and thereby circumventing the usual difficulty posed by electric dipole selection rules. Further novel molecular states are predicted to occur in the low- J states of silicon, which are strongly perturbed due to channel interactions between Rydberg series leading to the spin-orbit split ionization thresholds. These interactions manifest themselves in potential curves exhibiting two distinct length scales, providing novel opportunities for quantum manipulation. Supported in part by the National Science Foundation under Grant No. PHY-1306905.

  6. Metrological capabilities of Scanning Long Range Doppler Lidars

    NASA Astrophysics Data System (ADS)

    Loaec, Sophie; Boquet, Matthieu; Cariou, Jean-Pierre

    2013-04-01

    Many application areas are interested in getting wind measurements within the Planetary Boundary Layer (PBL) height, and with a relatively high accuracy. These applications include meteorology like PBL studies, air traffic safety like aircraft induced wake vortices and wind shears detection or wind farming like wind resources assessment. In order to answer these demands there are recent developments and deployments of long-range vertical profiler or fully hemispherical scanning wind lidars. To validate the measurements provided by such a system, it is possible to make inter-comparisons with a met mast at short distance and with wind profilers radar or sodar at longer distance. But, there are difficulties that may arise from the implementation of this kind of methodology because of the uncertainty related to the campaign set-up and the instruments used as reference. In that perspective Leosphere is developing a method to assess the accuracy of the Leosphere's lidars. In this presentation, we will give a detail description of the method and its results.

  7. Long-range forecasts of UK winter hydrology

    NASA Astrophysics Data System (ADS)

    Svensson, C.; Brookshaw, A.; Scaife, A. A.; Bell, V. A.; Mackay, J. D.; Jackson, C. R.; Hannaford, J.; Davies, H. N.; Arribas, A.; Stanley, S.

    2015-06-01

    Seasonal river flow forecasts are beneficial for planning agricultural activities, river navigation, and for management of reservoirs for public water supply and hydropower generation. In the United Kingdom (UK), skilful seasonal river flow predictions have previously been limited to catchments in lowland (southern and eastern) regions. Here we show that skilful long-range forecasts of winter flows can now be achieved across the whole of the UK. This is due to a remarkable geographical complementarity between the regional geological and meteorological sources of predictability for river flows. Forecast skill derives from the hydrogeological memory of antecedent conditions in southern and eastern parts of the UK and from meteorological predictability in northern and western areas. Specifically, it is the predictions of the atmospheric circulation over the North Atlantic that provides the skill at the seasonal timescale. In addition, significant levels of skill in predicting the frequency of winter high flow events is demonstrated, which has the potential to allow flood adaptation measures to be put in place.

  8. Long range transport of colloids in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Florea, Daniel; Musa, Sami; Huyghe, Jacques M. R. J.; Wyss, Hans M.

    2013-03-01

    Colloids in aqueous suspensions can experience strong, extremely long range repulsive forces near interfaces such as biological tissues, gels, ion exchange resins or metals. As a result exclusion zones extending over several millimeters can be formed. While this phenomenon has been previously described, a physical understanding of this process is still lacking. This exclusion zone formation is puzzling because the typical forces acting on colloidal particles are limited to much shorter distances and external fields that could drive the particles are absent. Here we study the exclusion zone formation in detail by following the time and distance-dependent forces acting on the particles. We present a simple model that accounts for our experimental data and directly links the exclusion zone formation to an already known physical transport phenomenon. We show that the effect can be tuned by changing the zeta potential of the particles or by varying the species present in the aqueous solution. We thus provide a direct physical explanation for the intriguing exclusion zone formation and we illustrate how this effect can be exploited in a range of industrial applications.

  9. Long-range position and orientation tracking system

    SciTech Connect

    Armstrong, G.A.; Jansen, J.F.; Burks, B.L.

    1995-12-31

    The long-range position and orientation tracking system will consist of two measurement pods, a VME-based computer system, and a detector array. The system is used to measure the position and orientation of a target that may be attached to a robotic arm, teleoperated manipulator, or autonomous vehicle. The pods have been designed to be mounted in the manways of the domes of the Fernald K-65 waste silos. Each pod has two laser scanner subsystems as well as lights and camera systems. One of the laser scanners will be oriented to scan in the pan direction, the other in the tilt direction. As the lasers scan across the detector array, the angles of incidence with each detector are recorded. Combining measurements from each of the four lasers yields sufficient data for a closed-form solution of the transform describing the location and orientation of the content mobilization system (CMS). Redundant detectors will be placed on the CMS to accommodate occlusions, to provide improved measurement accuracy, and to determine the CMS orientation.

  10. On long-range forces of repulsion between biological cells

    NASA Astrophysics Data System (ADS)

    Derjaguin, B. V.; Golovanov, M. V.

    1992-05-01

    We have established experimentally that when biological cells, for example, blood, are suspended in concentrated solutions of inorganic electrolytes (for instance, in a 15% solution of sodium chloride) then around some cells (leucocytes, especially tumour cells) there form haloes, i.e., circular spaces free from background cells (erythrocytes, yeast cells, colloidal particles of Indian ink). In the medium made up of erythrocytes the haloes form during 5-10 min as a result of the background cells drawing apart from the central halo-forming cell (HFC) at a distance of 10-100 μm and more. In the medium made of the Indian ink particles, the haloes form during 2-4 s and attain a thickness of about 10-20 μm. The erythrocytes and the haloes forming in their medium can be preserved for about three to five days at room temperature. It has been established that, when tumour HFCs are present at sufficient concentrations, they form hexagonal periodic structures having a mean spacing between cells of up to 60 μm. The authors put forward as one probable suggestion that the formation of haloes is largely determined by long-range repulsive forces arising from the phenomenon of diffusiophoresis generated by the diffusion currents that emerge from the surface of halo-forming cells.