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Sample records for exploit hybrid-polariton resonances

  1. Nanostructures Exploit Hybrid-Polariton Resonances

    NASA Technical Reports Server (NTRS)

    Anderson, Mark

    2008-01-01

    Nanostructured devices that exploit the hybrid-polariton resonances arising from coupling among photons, phonons, and plasmons are subjects of research directed toward the development of infrared-spectroscopic sensors for measuring extremely small quantities of molecules of interest. The spectroscopic techniques in question are surface enhanced Raman scattering (SERS) and surface enhanced infrared absorption (SEIRA). An important intermediate goal of this research is to increase the sensitivity achievable by these techniques. The basic idea of the approach being followed in this research is to engineer nanostructured devices and thereby engineer their hybrid-polariton resonances to concentrate infrared radiation incident upon their surfaces in such a manner as to increase the absorption of the radiation for SEIRA and measure the frequency shifts of surface vibrational modes. The underlying hybrid-polariton-resonance concept is best described by reference to experimental devices that have been built and tested to demonstrate the concept. The nanostructure of each such device includes a matrix of silicon carbide particles of approximately 1 micron in diameter that are supported on a potassium bromide (KBr) or poly(tetrafluoroethylene) [PTFE] window. These grains are sputter-coated with gold grains of 40-nm size (see figure). From the perspective of classical electrodynamics, in this nanostructure, that includes a particulate or otherwise rough surface, the electric-field portion of an incident electromagnetic field becomes concentrated on the particles when optical resonance conditions are met. Going beyond the perspective of classical electrodynamics, it can be seen that when the resonance frequencies of surface phonons and surface plasmons overlap, the coupling of the resonances gives rise to an enhanced radiation-absorption or -scattering mechanism. The sizes, shapes, and aggregation of the particles determine the frequencies of the resonances. Hence, the task of

  2. Hybrid polaritons in a resonant inorganic/organic semiconductor microcavity

    SciTech Connect

    Höfner, M. Sadofev, S.; Henneberger, F.; Kobin, B.; Hecht, S.

    2015-11-02

    We demonstrated the strong coupling regime in a hybrid inorganic-organic microcavity consisting of (Zn,Mg)O quantum wells and ladder-type oligo(p-phenylene) molecules embedded in a polymer matrix. A Fabry-Pérot cavity is formed by an epitaxially grown lower ZnMgO Bragg reflector and a dielectric mirror deposited atop of the organic layer. A clear anticrossing behavior of the polariton branches related to the Wannier-Mott and Frenkel excitons, and the cavity photon mode with a Rabi-splitting reaching 50 meV, is clearly identified by angular-dependent reflectivity measurements at low temperature. By tailoring the structural design, an equal mixing with weights of about 0.3 for all three resonances is achieved for the middle polariton branch at an incidence angle of about 35°.

  3. Exploiting Quantum Resonance to Solve Combinatorial Problems

    NASA Technical Reports Server (NTRS)

    Zak, Michail; Fijany, Amir

    2006-01-01

    Quantum resonance would be exploited in a proposed quantum-computing approach to the solution of combinatorial optimization problems. In quantum computing in general, one takes advantage of the fact that an algorithm cannot be decoupled from the physical effects available to implement it. Prior approaches to quantum computing have involved exploitation of only a subset of known quantum physical effects, notably including parallelism and entanglement, but not including resonance. In the proposed approach, one would utilize the combinatorial properties of tensor-product decomposability of unitary evolution of many-particle quantum systems for physically simulating solutions to NP-complete problems (a class of problems that are intractable with respect to classical methods of computation). In this approach, reinforcement and selection of a desired solution would be executed by means of quantum resonance. Classes of NP-complete problems that are important in practice and could be solved by the proposed approach include planning, scheduling, search, and optimal design.

  4. Electrically tunable organic–inorganic hybrid polaritons with monolayer WS2

    PubMed Central

    Flatten, Lucas C.; Coles, David M.; He, Zhengyu; Lidzey, David G.; Taylor, Robert A.; Warner, Jamie H.; Smith, Jason M.

    2017-01-01

    Exciton-polaritons are quasiparticles consisting of a linear superposition of photonic and excitonic states, offering potential for nonlinear optical devices. The excitonic component of the polariton provides a finite Coulomb scattering cross section, such that the different types of exciton found in organic materials (Frenkel) and inorganic materials (Wannier-Mott) produce polaritons with different interparticle interaction strength. A hybrid polariton state with distinct excitons provides a potential technological route towards in situ control of nonlinear behaviour. Here we demonstrate a device in which hybrid polaritons are displayed at ambient temperatures, the excitonic component of which is part Frenkel and part Wannier-Mott, and in which the dominant exciton type can be switched with an applied voltage. The device consists of an open microcavity containing both organic dye and a monolayer of the transition metal dichalcogenide WS2. Our findings offer a perspective for electrically controlled nonlinear polariton devices at room temperature. PMID:28094281

  5. Electrically tunable organic-inorganic hybrid polaritons with monolayer WS2

    NASA Astrophysics Data System (ADS)

    Flatten, Lucas C.; Coles, David M.; He, Zhengyu; Lidzey, David G.; Taylor, Robert A.; Warner, Jamie H.; Smith, Jason M.

    2017-01-01

    Exciton-polaritons are quasiparticles consisting of a linear superposition of photonic and excitonic states, offering potential for nonlinear optical devices. The excitonic component of the polariton provides a finite Coulomb scattering cross section, such that the different types of exciton found in organic materials (Frenkel) and inorganic materials (Wannier-Mott) produce polaritons with different interparticle interaction strength. A hybrid polariton state with distinct excitons provides a potential technological route towards in situ control of nonlinear behaviour. Here we demonstrate a device in which hybrid polaritons are displayed at ambient temperatures, the excitonic component of which is part Frenkel and part Wannier-Mott, and in which the dominant exciton type can be switched with an applied voltage. The device consists of an open microcavity containing both organic dye and a monolayer of the transition metal dichalcogenide WS2. Our findings offer a perspective for electrically controlled nonlinear polariton devices at room temperature.

  6. Microrheological Coagulation Assay Exploiting Micromechanical Resonators.

    PubMed

    Padovani, Francesco; Duffy, James; Hegner, Martin

    2017-01-03

    Rheological measurements in biological liquids yield insights into homeostasis and provide information on important molecular processes that affect fluidity. We present a fully automated cantilever-based method for highly precise and sensitive measurements of microliter sample volumes of human blood plasma coagulation (0.009 cP for viscosity range 0.5-3 cP and 0.0012 g/cm(3) for density range 0.9-1.1 g/cm(3)). Microcantilever arrays are driven by a piezoelectric element, and resonance frequencies and quality factors of sensors that change over time are evaluated. A highly accurate approximation of the hydrodynamic function is introduced that correlates resonance frequency and quality factor of cantilever beams immersed in a fluid to the viscosity and density of that fluid. The theoretical model was validated using glycerol reference solutions. We present a surface functionalization protocol that allows minimization of unspecific protein adsorption onto cantilevers. Adsorption leads to measurement distortions and incorrect estimation of the fluid parameters (viscosity and density). Two hydrophilic terminated self-assembled monolayers (SAMs) sensor surfaces are compared to a hydrophobic terminated SAM coating. As expected, the hydrophobic modified surfaces induced the highest mass adsorption and could promote conformational changes of the proteins and subsequent abnormal biological activity. Finally, the activated partial thromboplastin time (aPTT) coagulation assay was performed, and the viscosity, density, and coagulation rate of human blood plasma were measured along with the standard coagulation time. The method could extend and improve current coagulation testing.

  7. Exploiting the principle parametric resonance of an electric oscillator for vibratory energy harvesting

    NASA Astrophysics Data System (ADS)

    Caldwell, N. B.; Daqaq, M. F.

    2017-02-01

    Vibratory energy harvesters typically exploit ordinary direct resonances to mechanically amplify environmental inputs before channeling a portion of their energy into an electric load using an electromechanical transduction mechanism. Nonetheless, parametric resonance which has also been recently exploited, but to a lesser extent, holds a key advantage over direct excitations in that, when the level of input excitation exceeds a certain threshold, the amplitude of growth associated with parametric pumping is not limited by the total linear damping present in the system. While all of the previous research studies using parametric resonances for energy harvesting focused on utilizing it as a means of mechanical amplification, this letter demonstrates that vibratory excitations can also be used effectively to induce parametric resonances in the harvesting circuit itself, thereby providing a direct and simple means of electric amplification. A vibratory energy harvester exploiting this phenomenon is proposed in this letter and is shown to produce a maximum of 18 mW root-mean-square power per 1 g of input acceleration.

  8. Properties of ultrasonic acoustic resonances for exploitation in comb construction by social hornets and honeybees

    NASA Astrophysics Data System (ADS)

    Kadmon, Jonathan; Ishay, Jacob S.; Bergman, David J.

    2009-06-01

    Physical and mathematical considerations are presented in support of the suggestion that social hornets and bees, which construct brood combs with large arrays of cells in a honeycomb structure, exploit ultrasonic acoustic resonances in those cells in order to achieve the great accuracy of the hexagonal symmetry exhibited by these honeycomb-structured arrays. We present a numerical calculation of those resonances for the case of a perfect-hexagon duct utilizing a Bloch-Floquet-type theorem. We calculate the rate of energy dissipation in those resonances and use that, along with other considerations, to identify the resonance that is best suited for the suggested use by bees and hornets. Previously recorded ultrasonic data on social hornets and honeybees are cited which agree with some of our predictions and thus provide support for the above-mentioned suggestion.

  9. Properties of ultrasonic acoustic resonances for exploitation in comb construction by social hornets and honeybees.

    PubMed

    Kadmon, Jonathan; Ishay, Jacob S; Bergman, David J

    2009-06-01

    Physical and mathematical considerations are presented in support of the suggestion that social hornets and bees, which construct brood combs with large arrays of cells in a honeycomb structure, exploit ultrasonic acoustic resonances in those cells in order to achieve the great accuracy of the hexagonal symmetry exhibited by these honeycomb-structured arrays. We present a numerical calculation of those resonances for the case of a perfect-hexagon duct utilizing a Bloch-Floquet-type theorem. We calculate the rate of energy dissipation in those resonances and use that, along with other considerations, to identify the resonance that is best suited for the suggested use by bees and hornets. Previously recorded ultrasonic data on social hornets and honeybees are cited which agree with some of our predictions and thus provide support for the above-mentioned suggestion.

  10. Piezoelectric vibration-driven locomotion systems - Exploiting resonance and bistable dynamics

    NASA Astrophysics Data System (ADS)

    Fang, Hongbin; Wang, K. W.

    2017-03-01

    While a piezoelectric-based vibration-driven system is an excellent candidate for actuating small-size crawling-type locomotion robots, it has the major drawback of limited stroke output that would severely constraint the system's locomotion performance. In this paper, to advance the state of the art, we propose two novel designs of piezoelectric vibration-driven locomotion systems. The first utilizes the resonant amplification concept, and the second explores the design of a bistable device. While these two ideas have been explored for piezoelectric actuation amplification in general, they have never been exploited for crawling-type robotic locomotion. Numerical analyses on both systems reveal that resonance and bistability can substantially increase the systems' average locomotion speed. Moreover, this research shows that with bistability, the system is able to output high average locomotion speed in a wider frequency band, possess multiple locomotion modes, and achieve fast switches among them. Through proof-of-concept prototypes, the predicted locomotion performance improvements brought by resonance and bistability are verified. Finally, the basin stability is evaluated to systematically describe the occurring probability of certain locomotion behavior of the bistable system, which would provide useful guideline to the design and control of bistable vibration-driven locomotion systems.

  11. A wireless interrogation system exploiting narrowband acoustic resonator for remote physical quantity measurement

    NASA Astrophysics Data System (ADS)

    Friedt, J.-M.; Droit, C.; Martin, G.; Ballandras, S.

    2010-01-01

    Monitoring physical quantities using acoustic wave devices can be advantageously achieved using the wave characteristic dependence to various parametric perturbations (temperature, stress, and pressure). Surface acoustic wave (SAW) resonators are particularly well suited to such applications as their resonance frequency is directly influenced by these perturbations, modifying both the phase velocity and resonance conditions. Moreover, the intrinsic radio frequency (rf) nature of these devices makes them ideal for wireless applications, mainly exploiting antennas reciprocity and piezoelectric reversibility. In this paper, we present a wireless SAW sensor interrogation unit operating in the 434 MHz centered ISM band—selected as a tradeoff between antenna dimensions and electromagnetic wave penetration in dielectric media—based on the principles of a frequency sweep network analyzer. We particularly focus on the compliance with the ISM standard which reveals complicated by the need for switching from emission to reception modes similarly to radar operation. In this matter, we propose a fully digital rf synthesis chain to develop various interrogation strategies to overcome the corresponding difficulties and comply with the above-mentioned standard. We finally assess the reader interrogation range, accuracy, and dynamics.

  12. A wireless interrogation system exploiting narrowband acoustic resonator for remote physical quantity measurement

    SciTech Connect

    Friedt, J.-M; Droit, C.; Martin, G.; Ballandras, S.

    2010-01-15

    Monitoring physical quantities using acoustic wave devices can be advantageously achieved using the wave characteristic dependence to various parametric perturbations (temperature, stress, and pressure). Surface acoustic wave (SAW) resonators are particularly well suited to such applications as their resonance frequency is directly influenced by these perturbations, modifying both the phase velocity and resonance conditions. Moreover, the intrinsic radio frequency (rf) nature of these devices makes them ideal for wireless applications, mainly exploiting antennas reciprocity and piezoelectric reversibility. In this paper, we present a wireless SAW sensor interrogation unit operating in the 434 MHz centered ISM band--selected as a tradeoff between antenna dimensions and electromagnetic wave penetration in dielectric media--based on the principles of a frequency sweep network analyzer. We particularly focus on the compliance with the ISM standard which reveals complicated by the need for switching from emission to reception modes similarly to radar operation. In this matter, we propose a fully digital rf synthesis chain to develop various interrogation strategies to overcome the corresponding difficulties and comply with the above-mentioned standard. We finally assess the reader interrogation range, accuracy, and dynamics.

  13. Mid-infrared plasmonic resonances exploiting heavily-doped Ge on Si

    NASA Astrophysics Data System (ADS)

    Biagioni, P.; Sakat, E.; Baldassarre, L.; Calandrini, E.; Samarelli, A.; Gallacher, K.; Frigerio, J.; Isella, G.; Paul, D. J.; Ortolani, M.

    2015-03-01

    We address the behavior of mid-infrared localized plasmon resonances in elongated germanium antennas integrated on silicon substrates. Calculations based on Mie theory and on the experimentally retrieved dielectric constant allow us to study the tunability and the figures of merit of plasmon resonances in heavily-doped germanium and to preliminarily compare them with those of the most established plasmonic material, gold.

  14. Spacecraft transfer trajectory design exploiting resonant orbits in multi-body environments

    NASA Astrophysics Data System (ADS)

    Vaquero Escribano, Tatiana Mar

    Historically, resonant orbits have been employed in mission design for multiple planetary flyby trajectories and, more recently, as a source of long-term orbital stability. For instance, in support of a mission concept in NASA's Outer Planets Program, the Jupiter Europa Orbiter spacecraft is designed to encounter two different resonances with Europa during the 'endgame' phase, leading to Europa orbit insertion on the final pass. In 2011, the Interstellar Boundary Explorer spacecraft was inserted into a stable out-of-plane lunar-resonant orbit, the first of this type for a spacecraft in a long-term Earth orbit. However, resonant orbits have not yet been significantly explored as transfer mechanisms between non-resonant orbits in multi-body systems. This research effort focuses on incorporating resonant orbits into the design process to potentially enable the construction of more efficient or even novel transfer scenarios. Thus, the goals in this investigation are twofold: i) to expand the orbit architecture in multi-body environments by cataloging families of resonant orbits, and ii) to assess the role of such families in the design of transfer trajectories with specific patterns and itineraries. The benefits and advantages of employing resonant orbits in the design process are demonstrated through a variety of astrodynamics applications in several multi-body systems. In the Earth-Moon system, locally optimal transfer trajectories from low Earth orbit to selected libration point orbits are designed by leveraging conic arcs and invariant manifolds associated with resonant orbits. Resonant manifolds in the Earth-Moon system offer trajectories that tour the entire space within reasonable time intervals, facilitating the design of libration point orbit tours as well as Earth-Moon cyclers. In the Saturnian system, natural transitions between resonant and libration point orbits are sought and the problem of accessing Hyperion from orbits that are resonant with Titan is

  15. Note: A frequency modulated wireless interrogation system exploiting narrowband acoustic resonator for remote physical quantity measurement

    NASA Astrophysics Data System (ADS)

    Droit, C.; Martin, G.; Ballandras, S.; Friedt, J.-M.

    2010-05-01

    We demonstrate the wireless conversion of frequency modulation to amplitude modulation by radio frequency resonators as means of accurately determining the resonance frequency of passive acoustoelectronic sensors. The emitted frequency modulated radio frequency pulses are generated by a pulsed radar for probing a surface acoustic wave based sensor. The sharp sign transition of the amplitude modulated received signal provides a signal on which a feedback loop is locked to monitor the resonance signal. The strategy is demonstrated using a full software implementation on a generic hardware, resulting in 2 Hz resolution at 1 s integration time limited by the proportional feedback loop.

  16. Note: A frequency modulated wireless interrogation system exploiting narrowband acoustic resonator for remote physical quantity measurement.

    PubMed

    Droit, C; Martin, G; Ballandras, S; Friedt, J-M

    2010-05-01

    We demonstrate the wireless conversion of frequency modulation to amplitude modulation by radio frequency resonators as means of accurately determining the resonance frequency of passive acoustoelectronic sensors. The emitted frequency modulated radio frequency pulses are generated by a pulsed radar for probing a surface acoustic wave based sensor. The sharp sign transition of the amplitude modulated received signal provides a signal on which a feedback loop is locked to monitor the resonance signal. The strategy is demonstrated using a full software implementation on a generic hardware, resulting in 2 Hz resolution at 1 s integration time limited by the proportional feedback loop.

  17. Exploiting jet binning to identify the initial state of high-mass resonances

    NASA Astrophysics Data System (ADS)

    Ebert, Markus A.; Liebler, Stefan; Moult, Ian; Stewart, Iain W.; Tackmann, Frank J.; Tackmann, Kerstin; Zeune, Lisa

    2016-09-01

    If a new high-mass resonance is discovered at the Large Hadron Collider, model-independent techniques to identify the production mechanism will be crucial to understand its nature and effective couplings to Standard Model particles. We present a powerful and model-independent method to infer the initial state in the production of any high-mass color-singlet system by using a tight veto on accompanying hadronic jets to divide the data into two mutually exclusive event samples (jet bins). For a resonance of several hundred GeV, the jet binning cut needed to discriminate quark and gluon initial states is in the experimentally accessible range of several tens of GeV. It also yields comparable cross sections for both bins, making this method viable already with the small event samples available shortly after a discovery. Theoretically, the method is made feasible by utilizing an effective field theory setup to compute the jet cut dependence precisely and model independently and to systematically control all sources of theoretical uncertainties in the jet binning, as well as their correlations. We use a 750 GeV scalar resonance as an example to demonstrate the viability of our method.

  18. On Planning and Exploiting Schumann Resonance Measurements for Monitoring the Electrical Productivity of Global Lightning Activity

    NASA Astrophysics Data System (ADS)

    Mushtak, V. C.; Williams, E.

    2010-12-01

    The spatial-temporal behavior of world-wide lightning activity can be effectively used as an indicator of various geophysical processes, the global climate change being of a special interest among them. Since it has been reliably established that the lightning activity presents a major source of natural electromagnetic background in the Schumann resonance (SR) frequency range (5 to 40 Hz), SR measurements provide a continuous flow of information about this globally distributed source, thus forming an informative basis for monitoring its behavior via an inversion of observations into the source’s properties. To have such an inversion procedure effective, there is a series of prerequisites to comply with when planning and realizing it: (a) a proper choice of observable parameters to be used in the inversion; (b) a proper choice of a forward propagation model that would be accurate enough to take into consideration the major propagation effects occurring between a source and observer; (c) a proper choice of a method for inverting the sensitivity matrix. While the prerequisite (a) is quite naturally fulfilled by considering the SR resonance characteristics (modal frequencies, intensities, and quality factors), the compliance with prerequisites (b) and (c) has benefitted greatly from earlier seminal work on geophysical inversion by T.R. Madden. Since it has been found that the electrodynamic non-uniformities of the Earth-ionosphere waveguide, primarily the day/night, play an essential role in low-frequency propagation, use has been made of theory for the two-dimensional telegraph equation (TDTE; Kirillov, 2002) developed on the basis of the innovative suggestion by Madden and Thompson (1965) to consider the waveguide, both physically and mathematically, by analogy with a two-dimensional transmission line. Because of the iterative nature of the inversion procedure and the complicated, non-analytical character of the propagation theory, a special, fast-running TDTE

  19. Exploiting concave-convex linear resonators to design end-pumped solid-state lasers with flexible cavity lengths: Application for exploring the self-mode-locked operation.

    PubMed

    Tuan, P H; Chang, C C; Lee, C Y; Cho, C Y; Liang, H C; Chen, Y F

    2016-11-14

    The characteristics of a convex-concave linear resonator under the thermal lensing effect are theoretically analyzed to find an analytical model for designing end-pumped solid-state lasers with flexible cavity lengths. By exploiting the design model, the power scaling for continuous-wave operation under strong thermal lensing can be easily achieved in the proposed resonator with different cavity lengths. Furthermore, the proposed resonator is applied to explore the exclusive influence of cavity length on the self-mode-locked (SML) operation. It is discovered that the lasing longitudinal modes will split into multiple groups in optical spectrum to lead to a multi-pulse mode-locked temporal state when the cavity length increases. Finally, a theoretical model is derived to reconstruct the experimental results of SML operation to deduce a simple relationship between the group number of lasing modes and the cavity length.

  20. Exploiting jump-resonance hysteresis in silicon auditory front-ends for extracting speaker discriminative formant trajectories.

    PubMed

    Aono, Kenji; Shaga, Ravi K; Chakrabartty, Shantanu

    2013-08-01

    Jump-resonance is a phenomenon observed in non-linear circuits where the amplitude of the output signal exhibits an abrupt jump when the frequency of the input signal is varied. For [Formula: see text] filters used in the design of analog auditory front-ends (AFEs), jump-resonance is generally considered to be undesirable and several techniques have been proposed in literature to avoid or alleviate this artifact. In this paper we explore the use of jump-resonance based hysteresis in [Formula: see text] band-pass filters for encoding speech formant trajectories. Using prototypes of silicon AFEs fabricated in a 0.5 μm CMOS process, we demonstrate the benefits of the proposed approach for extracting speaker discriminative features. These benefits are validated using speaker recognition experiments where consistent improvements in equal-error-rates (EERs) are achieved using the jump-resonance based features as compared to conventional features.

  1. Picosecond optically reconfigurable filters exploiting full free spectral range tuning of single ring and Vernier effect resonators.

    PubMed

    Bruck, Roman; Mills, Ben; Thomson, David J; Troia, Benedetto; Passaro, Vittorio M N; Mashanovich, Goran Z; Reed, Graham T; Muskens, Otto L

    2015-05-04

    We demonstrate that phase shifts larger than 2π can be induced by all-optical tuning in silicon waveguides of a few micrometers in length. By generating high concentrations of free carriers in the silicon employing absorption of ultrashort, ultraviolet laser pulses, the refractive index of silicon can be drastically reduced. As a result, the resonance wavelength of optical resonators can be freely tuned over the full free spectral range. This allows for active integrated optic devices that can be switched with GHz frequencies into any desired state by all-optical means.

  2. Magnetic resonance imaging for the exploitation of bubble-enhanced heating by high-intensity focused ultrasound: a feasibility study in ex vivo liver.

    PubMed

    Elbes, Delphine; Denost, Quentin; Robert, Benjamin; Köhler, Max O; Tanter, Mickaël; Bruno, Quesson

    2014-05-01

    Bubble-enhanced heating (BEH) may be exploited to improve the heating efficiency of high-intensity focused ultrasound in liver and to protect tissues located beyond the focal point. The objectives of this study, performed in ex vivo pig liver, were (i) to develop a method to determine the acoustic power threshold for induction of BEH from displacement images measured by magnetic resonance acoustic radiation force imaging (MR-ARFI), and (ii) to compare temperature distribution with MR thermometry for HIFU protocols with and without BEH. The acoustic threshold for generation of BEH was determined in ex vivo pig liver from MR-ARFI calibration curves of local tissue displacement resulting from sonication at different powers. Temperature distributions (MR thermometry) resulting from "conventional" sonications (20 W, 30 s) were compared with those from "composite" sonications performed at identical parameters, but after a HIFU burst pulse (0.5 s, acoustic power over the threshold for induction of BEH). Displacement images (MR-ARFI) were acquired between sonications to measure potential modifications of local tissue displacement associated with modifications of tissue acoustic characteristics induced by the burst HIFU pulse. The acoustic threshold for induction of BEH corresponded to a displacement amplitude of approximately 50 μm in ex vivo liver. The displacement and temperature images of the composite group exhibited a nearly spherical pattern, shifted approximately 4 mm toward the transducer, in contrast to elliptical shapes centered on the natural focal position for the conventional group. The gains in maximum temperature and displacement values were 1.5 and 2, and the full widths at half-maximum of the displacement data were 1.7 and 2.2 times larger than in the conventional group in directions perpendicular to ultrasound propagation axes. Combination of MR-ARFI and MR thermometry for calibration and exploitation of BEH appears to increase the efficiency and safety

  3. Belowground plant development measured with magnetic resonance imaging (MRI): exploiting the potential for non-invasive trait quantification using sugar beet as a proxy

    PubMed Central

    Metzner, Ralf; van Dusschoten, Dagmar; Bühler, Jonas; Schurr, Ulrich; Jahnke, Siegfried

    2014-01-01

    Both structural and functional properties of belowground plant organs are critical for the development and yield of plants but, compared to the shoot, much more difficult to observe due to soil opacity. Many processes concerning the belowground plant performance are not fully understood, in particular spatial and temporal dynamics and their interrelation with environmental factors. We used Magnetic Resonance Imaging (MRI) as a noninvasive method to evaluate which traits can be measured when a complex plant organ is monitored in-vivo while growing in the soil. We chose sugar beet (Beta vulgaris ssp. vulgaris) as a model system. The beet consists mainly of root tissues, is rather complex regarding tissue structure and responses to environmental factors, and thereby a good object to test the applicability of MRI for 3D phenotyping approaches. Over a time period of up to 3 months, traits such as beet morphology or anatomy were followed in the soil and the effect of differently sized pots on beet fresh weight calculated from MRI data was studied. There was a clear positive correlation between the pot size and the increase in fresh weight of a sugar beet over time. Since knowledge of the development of internal beet structures with several concentric cambia, vascular and parenchyma rings is still limited, we consecutively acquired 3D volumetric images on individual plants using the MRI contrast parameter T2 to map the development of rings at the tissue level. This demonstrates that MRI provides versatile protocols to non-invasively measure plant traits in the soil. It opens new avenues to investigate belowground plant performance under adverse environmental conditions such as drought, nutrient shortage, or soil compaction to seek for traits of belowground organs making plants more resilient to stress. PMID:25278947

  4. The Exploitation of Drug Users.

    PubMed

    Stallings, Shirley; Montagne, Michael

    2015-01-01

    Drug users have been exploited in research studies and clinical practice. We explore ways in which exploitation has occurred and strategies to help patients, research subjects and communities to prevent or avoid exploitation.

  5. Multisensor staring exploitation

    NASA Astrophysics Data System (ADS)

    Bryant, Michael L.

    2008-04-01

    The focus of this paper is on the exploitation of new staring sensors to address the urban surveillance challenge and help combat the war on terror. A staring sensor visualization environment, known as the Data Table, will be presented which integrates staring sensors with close-in sensors, such as small UAVs, building mounted sensors, and unattended ground sensors (UGS). There are several staring sensors in development, but two in particular will be highlighted in this paper - NightStare and the Gotcha Radar, both under development by the Air Force Research Laboratory (AFRL).

  6. The Geohazards Exploitation Platform

    NASA Astrophysics Data System (ADS)

    Laur, Henri; Casu, Francesco; Bally, Philippe; Caumont, Hervé; Pinto, Salvatore

    2016-04-01

    The Geohazards Exploitation Platform, or Geohazards TEP (GEP), is an ESA originated R&D activity of the EO ground segment to demonstrate the benefit of new technologies for large scale processing of EO data. This encompasses on-demand processing for specific user needs, systematic processing to address common information needs of the geohazards community, and integration of newly developed processors for scientists and other expert users. The platform supports the geohazards community's objectives as defined in the context of the International Forum on Satellite EO and Geohazards organised by ESA and GEO in Santorini in 2012. The GEP is a follow on to the Supersites Exploitation Platform (SSEP) an ESA initiative to support the Geohazards Supersites & Natural Laboratories initiative (GSNL). Today the GEP allows to exploit 70+ Terabyte of ERS and ENVISAT archive and the Copernicus Sentinel-1 data available on line. The platform has already engaged 22 European early adopters in a validation activity initiated in March 2015. Since September, this validation has reached 29 single user projects. Each project is concerned with either integrating an application, running on demand processing or systematically generating a product collection using an application available in the platform. The users primarily include 15 geoscience centres and universities based in Europe: British Geological Survey (UK), University of Leeds (UK), University College London (UK), ETH University of Zurich (CH), INGV (IT), CNR-IREA and CNR-IRPI (IT), University of L'Aquila (IT), NOA (GR), Univ. Blaise Pascal & CNRS (FR), Ecole Normale Supérieure (FR), ISTERRE / University of Grenoble-Alpes (FR). In addition, there are users from Africa and North America with the University of Rabat (MA) and the University of Miami (US). Furthermore two space agencies and four private companies are involved: the German Space Research Centre DLR (DE), the European Space Agency (ESA), Altamira Information (ES

  7. Image exploitation for MISAR

    NASA Astrophysics Data System (ADS)

    Heinze, N.; Edrich, M.; Saur, G.; Krüger, W.

    2007-04-01

    The miniature SAR-system MiSAR has been developed by EADS Germany for lightweight UAVs like the LUNASystem. MiSAR adds to these tactical UAV-systems the all-weather reconnaissance capability, which is missing until now. Unlike other SAR sensors, that produce large strip maps at update rates of several seconds, MiSAR generates sequences of SAR images with approximately 1 Hz frame rate. photo interpreters (PI) of tactical drones, now mainly experienced with visual interpretation, are not used to SARimages, especially not with SAR-image sequence characteristics. So they should be supported to improve their ability to carry out their task with a new, demanding sensor system. We have therefore analyzed and discussed with military PIs in which task MiSAR can be used and how the PIs can be supported by special algorithms. We developed image processing- and exploitation-algorithms for such SAR-image sequences. A main component is the generation of image sequence mosaics to get more oversight. This mosaicing has the advantage that also non straight /linear flight-paths and varying squint angles can be processed. Another component is a screening-component for manmade objects to mark regions of interest in the image sequences. We use a classification based approach, which can be easily adapted to new sensors and scenes. These algorithms are integrated into an image exploitation system to improve the image interpreters ability to get a better oversight, better orientation and helping them to detect relevant objects, especially considering long endurance reconnaissance missions.

  8. Exploiting Non-Markovianity for Quantum Control

    NASA Astrophysics Data System (ADS)

    Reich, Daniel M.; Katz, Nadav; Koch, Christiane P.

    2015-07-01

    Quantum technology, exploiting entanglement and the wave nature of matter, relies on the ability to accurately control quantum systems. Quantum control is often compromised by the interaction of the system with its environment since this causes loss of amplitude and phase. However, when the dynamics of the open quantum system is non-Markovian, amplitude and phase flow not only from the system into the environment but also back. Interaction with the environment is then not necessarily detrimental. We show that the back-flow of amplitude and phase can be exploited to carry out quantum control tasks that could not be realized if the system was isolated. The control is facilitated by a few strongly coupled, sufficiently isolated environmental modes. Our paradigmatic example considers a weakly anharmonic ladder with resonant amplitude control only, restricting realizable operations to SO(N). The coupling to the environment, when harnessed with optimization techniques, allows for full SU(N) controllability.

  9. AMU NEXRAD Exploitation Task

    NASA Technical Reports Server (NTRS)

    Lambert, Winifred C.; Wheeler, Mark M.

    1997-01-01

    This report documents the results of the Applied Meteorology Unit's NEXRAD Exploitation Task. The objectives of this task are to determine what radar signatures are present prior to and at the time of convection initiation, and to determine radar signatures which will help distinguish whether the ensuing convection will become severe. Radar data from the WSR-88D radar located at NWS Melbourne (WSR-88D/KMLB) were collected between June and September 1995, and 16 convective case studies were analyzed for which the radar was operating during the entire period of interest. All WSR-88D/KMLB products were scrutinized for their utility in detecting convection initiation and severe storm signatures. Through process of elimination, it was found that the 0.5 deg reflectivity product with the lowest reflectivity values displayed is the best product to monitor for convection initiation signatures. Seven meteorological features associated with the initiation of deep convection were identified: the Merritt Island and Indian River convergence zones, interlake convergence, horizontal convective rolls, the sea breeze, storm outflow boundaries, and fires. Their reflectivity values ranged from -5 to 20 dBZ. Of the three severe weather phenomena (winds greater than or equal to 50 kts, tornado, 3/4 inch hail), high wind events due to microbursts were most common in the data set. It was found that the values and trends of composite reflectivity, vertically integrated liquid, and core aspect ratio were key indicators of the potential of a cell to produce a microburst. The data were not analyzed for the other two severe weather phenomena because they rarely occurred during the data collection period. This report also includes suggestions for new WSR-88D products, summaries of ongoing research aimed at creating new products, and explicit recommended procedures for detecting convection initiation and severe storm signatures in the radar data using the currently available technology.

  10. Reconfigurable optical routers based on Coupled Resonator Induced Transparency resonances.

    PubMed

    Mancinelli, M; Bettotti, P; Fedeli, J M; Pavesi, L

    2012-10-08

    The interferometric coupling of pairs of resonators in a resonator sequence generates coupled ring induced transparency (CRIT) resonances. These have quality factors an order of magnitude greater than those of single resonators. We show that it is possible to engineer CRIT resonances in tapered SCISSOR (Side Coupled Integrated Space Sequence of Resonator) to realize fast and efficient reconfigurable optical switches and routers handling several channels while keeping single channel addressing capabilities. Tapered SCISSORs are fabricated in silicon-on-insulator technology. Furthermore, tapered SCISSORs show multiple-channel switching behavior that can be exploited in DWDM applications.

  11. Sensory exploitation and sexual conflict

    PubMed Central

    Arnqvist, Göran

    2006-01-01

    Much of the literature on male–female coevolution concerns the processes by which male traits and female preferences for these can coevolve and be maintained by selection. There has been less explicit focus on the origin of male traits and female preferences. Here, I argue that it is important to distinguish origin from subsequent coevolution and that insights into the origin can help us appreciate the relative roles of various coevolutionary processes for the evolution of diversity in sexual dimorphism. I delineate four distinct scenarios for the origin of male traits and female preferences that build on past contributions, two of which are based on pre-existing variation in quality indicators among males and two on exploitation of pre-existing sensory biases among females. Recent empirical research, and theoretical models, suggest that origin by sensory exploitation has been widespread. I argue that this points to a key, but perhaps transient, role for sexually antagonistic coevolution (SAC) in the subsequent evolutionary elaboration of sexual traits, because (i) sensory exploitation is often likely to be initially costly for individuals of the exploited sex and (ii) the subsequent evolution of resistance to sensory exploitation should often be associated with costs due to selective constraints. A review of a few case studies is used to illustrate these points. Empirical data directly relevant to the costs of being sensory exploited and the costs of evolving resistance is largely lacking, and I stress that such data would help determining the general importance of sexual conflict and SAC for the evolution of sexual dimorphism. PMID:16612895

  12. Resonances and resonance widths

    SciTech Connect

    Collins, T.

    1986-05-01

    Two-dimensional betatron resonances are much more important than their simple one-dimensional counterparts and exhibit a strong dependence on the betatron phase advance per cell. A practical definition of ''width'' is expanded upon in order to display these relations in tables. A primarily pedagogical introduction is given to explain the tables, and also to encourage a wider capability for deriving resonance behavior and wider use of ''designer'' resonances.

  13. The Exploitation of Black Athletes.

    ERIC Educational Resources Information Center

    Edwards, Harry

    1983-01-01

    Colleges and universities have not up held their end of the bargain with athletes, exploiting a disproportionate number of talented Black athletes by not providing the kind of education the students sought or needed and by applying rigid academic standards for eligibility. (MSE)

  14. Dark matters: exploitation as cooperation.

    PubMed

    Dasgupta, Partha

    2012-04-21

    The empirical literature on human cooperation contains studies of communitarian institutions that govern the provision of public goods and management of common property resources in poor countries. Scholars studying those institutions have frequently used the Prisoners' Dilemma game as their theoretical tool-kit. But neither the provision of local public goods nor the management of local common property resources involves the Prisoners' Dilemma. That has implications for our reading of communitarian institutions. By applying a fundamental result in the theory of repeated games to a model of local common property resources, it is shown that communitarian institutions can harbour exploitation of fellow members, something that would not be possible in societies where cooperation amounts to overcoming the Prisoners' Dilemma. The conclusion we should draw is that exploitation can masquerade as cooperation.

  15. Teotihuacan, tepeapulco, and obsidian exploitation.

    PubMed

    Charlton, T H

    1978-06-16

    Current cultural ecological models of the development of civilization in central Mexico emphasize the role of subsistence production techniques and organization. The recent use of established and productive archeological surface survey techniques along natural corridors of communication between favorable niches for cultural development within the Central Mexican symbiotic region resulted in the location of sites that indicate an early development of a decentralized resource exploitation, manufacturing, and exchange network. The association of the development of this system with Teotihuacán indicates the importance such nonsubsistence production and exchange had in the evolution of this first central Mexican civilization. The later expansion of Teotihuacán into more distant areas of Mesoamerica was based on this resource exploitation model. Later civilizations centered at Tula and Tenochtitlán also used such a model in their expansion.

  16. Routing Algorithm Exploits Spatial Relations

    NASA Technical Reports Server (NTRS)

    Okino, Clayton; Jennings, Esther

    2004-01-01

    A recently developed routing algorithm for broadcasting in an ad hoc wireless communication network takes account of, and exploits, the spatial relationships among the locations of nodes, in addition to transmission power levels and distances between the nodes. In contrast, most prior algorithms for discovering routes through ad hoc networks rely heavily on transmission power levels and utilize limited graph-topology techniques that do not involve consideration of the aforesaid spatial relationships. The present algorithm extracts the relevant spatial-relationship information by use of a construct denoted the relative-neighborhood graph (RNG).

  17. Theory of electrically controlled resonant tunneling spin devices

    NASA Technical Reports Server (NTRS)

    Ting, David Z. -Y.; Cartoixa, Xavier

    2004-01-01

    We report device concepts that exploit spin-orbit coupling for creating spin polarized current sources using nonmagnetic semiconductor resonant tunneling heterostructures, without external magnetic fields. The resonant interband tunneling psin filter exploits large valence band spin-orbit interaction to provide strong spin selectivity.

  18. Geometry-invariant resonant cavities

    PubMed Central

    Liberal, I.; Mahmoud, A. M.; Engheta, N.

    2016-01-01

    Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modelling to everyday life devices. The eigenfrequencies of conventional cavities are a function of their geometry, and, thus, the size and shape of a resonant cavity is selected to operate at a specific frequency. Here we demonstrate theoretically the existence of geometry-invariant resonant cavities, that is, resonators whose eigenfrequencies are invariant with respect to geometrical deformations of their external boundaries. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, such as epsilon-near-zero media, which enable decoupling of the temporal and spatial field variations in the lossless limit. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices. PMID:27010103

  19. Geometry-invariant resonant cavities

    NASA Astrophysics Data System (ADS)

    Liberal, I.; Mahmoud, A. M.; Engheta, N.

    2016-03-01

    Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modelling to everyday life devices. The eigenfrequencies of conventional cavities are a function of their geometry, and, thus, the size and shape of a resonant cavity is selected to operate at a specific frequency. Here we demonstrate theoretically the existence of geometry-invariant resonant cavities, that is, resonators whose eigenfrequencies are invariant with respect to geometrical deformations of their external boundaries. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, such as epsilon-near-zero media, which enable decoupling of the temporal and spatial field variations in the lossless limit. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices.

  20. Exploiting social evolution in biofilms.

    PubMed

    Boyle, Kerry E; Heilmann, Silja; van Ditmarsch, Dave; Xavier, Joao B

    2013-04-01

    Bacteria are highly social organisms that communicate via signaling molecules, move collectively over surfaces and make biofilm communities. Nonetheless, our main line of defense against pathogenic bacteria consists of antibiotics-drugs that target individual-level traits of bacterial cells and thus, regrettably, select for resistance against their own action. A possible solution lies in targeting the mechanisms by which bacteria interact with each other within biofilms. The emerging field of microbial social evolution combines molecular microbiology with evolutionary theory to dissect the molecular mechanisms and the evolutionary pressures underpinning bacterial sociality. This exciting new research can ultimately lead to new therapies against biofilm infections that exploit evolutionary cheating or the trade-off between biofilm formation and dispersal.

  1. Energy for lunar resource exploitation

    NASA Technical Reports Server (NTRS)

    Glaser, Peter E.

    1992-01-01

    Humanity stands at the threshold of exploiting the known lunar resources that have opened up with the access to space. America's role in the future exploitation of space, and specifically of lunar resources, may well determine the level of achievement in technology development and global economic competition. Space activities during the coming decades will significantly influence the events on Earth. The 'shifting of history's tectonic plates' is a process that will be hastened by the increasingly insistent demands for higher living standards of the exponentially growing global population. Key to the achievement of a peaceful world in the 21st century, will be the development of a mix of energy resources at a societally acceptable and affordable cost within a realistic planning horizon. This must be the theme for the globally applicable energy sources that are compatible with the Earth's ecology. It is in this context that lunar resources development should be a primary goal for science missions to the Moon, and for establishing an expanding human presence. The economic viability and commercial business potential of mining, extracting, manufacturing, and transporting lunar resource based materials to Earth, Earth orbits, and to undertake macroengineering projects on the Moon remains to be demonstrated. These extensive activities will be supportive of the realization of the potential of space energy sources for use on Earth. These may include generating electricity for use on Earth based on beaming power from Earth orbits and from the Moon to the Earth, and for the production of helium 3 as a fuel for advanced fusion reactors.

  2. Energy for lunar resource exploitation

    NASA Astrophysics Data System (ADS)

    Glaser, Peter E.

    1992-02-01

    Humanity stands at the threshold of exploiting the known lunar resources that have opened up with the access to space. America's role in the future exploitation of space, and specifically of lunar resources, may well determine the level of achievement in technology development and global economic competition. Space activities during the coming decades will significantly influence the events on Earth. The 'shifting of history's tectonic plates' is a process that will be hastened by the increasingly insistent demands for higher living standards of the exponentially growing global population. Key to the achievement of a peaceful world in the 21st century, will be the development of a mix of energy resources at a societally acceptable and affordable cost within a realistic planning horizon. This must be the theme for the globally applicable energy sources that are compatible with the Earth's ecology. It is in this context that lunar resources development should be a primary goal for science missions to the Moon, and for establishing an expanding human presence. The economic viability and commercial business potential of mining, extracting, manufacturing, and transporting lunar resource based materials to Earth, Earth orbits, and to undertake macroengineering projects on the Moon remains to be demonstrated. These extensive activities will be supportive of the realization of the potential of space energy sources for use on Earth. These may include generating electricity for use on Earth based on beaming power from Earth orbits and from the Moon to the Earth, and for the production of helium 3 as a fuel for advanced fusion reactors.

  3. Opportunistic exploitation: an overlooked pathway to extinction.

    PubMed

    Branch, Trevor A; Lobo, Aaron S; Purcell, Steven W

    2013-07-01

    How can species be exploited economically to extinction? Past single-species hypotheses examining the economic plausibility of exploiting rare species have argued that the escalating value of rarity allows extinction to be profitable. We describe an alternative pathway toward extinction in multispecies exploitation systems, termed 'opportunistic exploitation'. In this mode, highly valued species that are targeted first by fishing, hunting, and logging become rare, but their populations can decline further through opportunistic exploitation while more common but less desirable species are targeted. Effectively, expanding exploitation to more species subsidizes the eventual extinction of valuable species at low densities. Managers need to recognize conditions that permit opportunistic depletion and pass regulations to protect highly desirable species when exploitation can expand to other species.

  4. Design study for asteroidal exploitation

    NASA Astrophysics Data System (ADS)

    Adams, Carl; Blissit, Jim; Jarrett, Dave; Sanner, Rob; Yanagawa, Koji

    1985-08-01

    A systematic approach to asteroidal exploitation for the 1990 to 2010 time frame is presented as an initial step toward expanding the use of space beyond the space station by providing a source of lower cost materials. With only a limited amount of information known about the asteroids, reconnaissance and exploration phases to determine the exact locations and compositions of several earth-approaching asteroids are required. Earth-based telescopes are used to locate and study the asteroids, while unmanned probes will return samples of asteroidal material to earth for analysis. After these phases are completed, the retrieval of a 35,000 metric ton piece of the asteroid Anteros is undertaken. A cargo transporter uses magnetoplasmadynamic (MPD) arcjets outbound and a mass-driver using asteroidal material inbound. A crew ship uses ion engines. Low thrust trajectories are used for both spacecraft. A materials processing facility will manufacture propellant pellets and retrieve non-propellant materials for spacecraft use. The cost is 1/10th that to transport the same materials from earth to high earth orbit. The project will cost 25 percent less if done in conjunction with a lunar and Martian base.

  5. The Gaia scientific exploitation networks

    NASA Astrophysics Data System (ADS)

    Figueras, F.; Jordi, C.

    2015-05-01

    On July 2014 the Gaia satellite, placed at L2 since January 2014, finished their commissioning phase and started collecting high accurate scientific data. New and more realistic estimations of the astrometric, photometric and spectroscopic accuracy expected after five years mission operation (2014-2019) have been recently published in the Gaia Science Performance Web page. Here we present the coordination efforts and the activities being conducted through the two GREAT (Gaia Research for European Astronomy Training) European Networks, the GREAT-ESF, a programme supported by the European Science Foundation (2010-2015), and the GREAT-ITN network, from the European Union's Seventh Framework Programme (2011-2015). The main research theme of these networks is to unravel the origin and history of our home galaxy. Emphasis is placed on the research projects being conducted by the Spanish Researchers through these networks, well coordinated by the Red Española de Explotación Científica de Gaia (REG network, with more than 140 participants). Members of the REG play an important role on the collection of complementary spectroscopic data from ground based telescopes, on the development of new tools for an optimal scientific exploitation of Gaia data and on the preparation task to create the Gaia archive.

  6. Exploiting dual otoacoustic emission sources

    NASA Astrophysics Data System (ADS)

    Abdala, Carolina; Kalluri, Radha

    2015-12-01

    Two distinct processes generate otoacoustic emissions (OAEs). Reflection-source emissions, here recorded as stimulus frequency OAEs, are optimally informative at low sound levels and are more sensitive to slight hearing loss; they have been linked to cochlear amplifier gain and tuning. Distortion-source emissions are strongest at moderate-high sound levels and persist despite mild hearing loss; they likely originate in the nonlinear process of hair cell transduction. In this preliminary study, we exploit the unique features of each by generating a combined reflection-distortion OAE profile in normal hearing and hearing-impaired ears. Distortion-product (DP) and stimulus-frequency (SF) OAEs were recorded over a broad range of stimulus levels and frequencies. Individual I/O and transfer functions were generated for both emission types in each ear, and OAE peak strength, compression threshold, and rate of compression were calculated. These combined SFOAE and DPOAE features in normal and hearing-impaired ears may provide a potentially informative and novel index of hearing loss. This is an initial step toward utilizing OAE source in characterizing cochlear function and dysfunction.

  7. Sensitivity Limits of Nanomechanical Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Greaney, P. Alex

    2009-03-01

    The sensitivity limit of the recently proposed chemical sensing method, nanomechanical resonance spectroscopy (NRS) ootnotetextP.A. Greaney and J.C. Grossman, Nano Letters, 8, 2648-2652, (2008)., is investigated using classical molecular dynamics simulations. The NRS method exploits the preferential transfer of energy between resonant modes, using an array of nanomechanical resonators to interrogate the vibrational spectrum of an analyte directly. We report on the effects of solvent and complex analytes.

  8. Electrical Control of Optical Plasmon Resonance with Graphene

    DTIC Science & Technology

    2012-10-01

    at optical frequencies.10 Here we achieve efficient control of near- infrared plasmon resonance in a hybrid graphene-gold nanorod system. Exploiting...quality factor of gold nanorod plasmon. Our analysis shows that the plasmon− graphene coupling is remarkably strong: even a single electron in...events. KEYWORDS: Graphene, plasmon resonance, metamaterials, active plasmonics, gold nanorod , charge transfer sensor Surface plasmon resonance in

  9. The exploitation of Gestalt principles by magicians.

    PubMed

    Barnhart, Anthony S

    2010-01-01

    Magicians exploit a host of psychological principles in deceiving their audiences. Psychologists have recently attempted to pinpoint the most common psychological tendencies exploited by magicians. This paper highlights two co-occurring principles that appear to be the basis for many popular magic tricks: accidental alignment and good continuation.

  10. Expanding the Bandwidth of Slow and Fast Pulse Propagation in Coupled Micro-resonators

    NASA Technical Reports Server (NTRS)

    Smith, David D.; Chang, Hongrok

    2007-01-01

    Coupled resonators exhibit coherence effects which can be exploited for the delay or advancement of pulses with minimal distortion. The bandwidth and normalized pulse delay are simultaneously enhanced by proper choice of the inter-resonator couplings.

  11. A New Measure of Interpersonal Exploitativeness

    PubMed Central

    Brunell, Amy B.; Davis, Mark S.; Schley, Dan R.; Eng, Abbey L.; van Dulmen, Manfred H.M.; Wester, Kelly L.; Flannery, Daniel J.

    2013-01-01

    Measures of exploitativeness evidence problems with validity and reliability. The present set of studies assessed a new measure [the Interpersonal Exploitativeness Scale (IES)] that defines exploitativeness in terms of reciprocity. In Studies 1 and 2, 33 items were administered to participants. Exploratory and Confirmatory Factor Analysis demonstrated that a single factor consisting of six items adequately assess interpersonal exploitativeness. Study 3 results revealed that the IES was positively associated with “normal” narcissism, pathological narcissism, psychological entitlement, and negative reciprocity and negatively correlated with positive reciprocity. In Study 4, participants competed in a commons dilemma. Those who scored higher on the IES were more likely to harvest a greater share of resources over time, even while controlling for other relevant variables, such as entitlement. Together, these studies show the IES to be a valid and reliable measure of interpersonal exploitativeness. The authors discuss the implications of these studies. PMID:23755031

  12. Global Climate Responses to Anthropogenic Groundwater Exploitation

    NASA Astrophysics Data System (ADS)

    Zeng, Y.; Xie, Z.

    2015-12-01

    In this study, a groundwater exploitation scheme is incorporated into the earth system model, Community Earth System Model 1.2.0 (CESM1.2.0), which is called CESM1.2_GW, and the climatic responses to anthropogenic groundwater withdrawal are then investigated on global scale. The scheme models anthropogenic groundwater exploitation and consumption, which are then divided into agricultural irrigation, industrial use and domestic use. A group of 41-year ensemble groundwater exploitation simulations with six different initial conditions, and a group of ensemble control simulations without exploitation are conducted using the developed model CESM1.2_GW with water supplies and demands estimated. The results reveal that the groundwater exploitation and water consumption cause drying effects on soil moisture in deep layers and wetting effects in upper layers, along with a rapidly declining groundwater table in Central US, Haihe River Basin in China and Northern India and Pakistan where groundwater extraction are most severe in the world. The atmosphere also responds to anthropogenic groundwater exploitation. Cooling effects on lower troposphere appear in large areas of North China Plain and of Northern India and Pakistan. Increased precipitation occurs in Haihe River Basin due to increased evapotranspiration from irrigation. Decreased precipitation occurs in Northern India because water vapor here is taken away by monsoon anomalies induced by anthropogenic alteration of groundwater. The local reducing effects of anthropogenic groundwater exploitation on total terrestrial water storage evinces that water resource is unsustainable with the current high exploitation rate. Therefore, a balance between slow groundwater withdrawal and rapid human economic development must be achieved to maintain a sustainable water resource, especially in over-exploitation regions such as Central US, Northern China, India and Pakistan.

  13. Solid state optical refrigeration using stark manifold resonances in crystals

    DOEpatents

    Seletskiy, Denis V.; Epstein, Richard; Hehlen, Markus P.; Sheik-Bahae, Mansoor

    2017-02-21

    A method and device for cooling electronics is disclosed. The device includes a doped crystal configured to resonate at a Stark manifold resonance capable of cooling the crystal to a temperature of from about 110K to about 170K. The crystal host resonates in response to input from an excitation laser tuned to exploit the Stark manifold resonance corresponding to the cooling of the crystal.

  14. National Center for Missing and Exploited Children

    MedlinePlus

    ... Team HOPE provides peer and emotional support to families. Contact Us Legal Information DONATE Careers Site Index Copyright © 2016 National Center for Missing & Exploited Children. All rights reserved. This Web site ...

  15. Optical resonator

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    The invention discloses a semi-ring Fabry-Perot (SRFP) optical resonator structure comprising a medium including an edge forming a reflective facet and a waveguide within the medium, the waveguide having opposing ends formed by the reflective facet. The performance of the SRFP resonator can be further enhanced by including a Mach-Zehnder interferometer in the waveguide on one side of the gain medium. The optical resonator can be employed in a variety of optical devices. Laser structures using at least one SRFP resonator are disclosed where the resonators are disposed on opposite sides of a gain medium. Other laser structures employing one or more resonators on one side of a gain region are also disclosed.

  16. Exploiting Spatial Channel Occupancy Information in WLANs

    DTIC Science & Technology

    2014-05-15

    Exploiting Spatial Channel Occupancy Information in WLANs Michael N Krishnan Electrical Engineering and Computer Sciences University of California at...3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Exploiting Spatial Channel Occupancy Information in WLANs 5a. CONTRACT NUMBER...length adaptation, and 50% via carrier sense threshold adaptation. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT

  17. A review of droplet resonators: Operation method and application

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Li, Hanyang; Zhao, Liyuan; Wu, Bing; Liu, Shuangqiang; Liu, Yongjun; Yang, Jun

    2016-12-01

    Droplet resonators hold promise as a special class of optical cavities for numerous applications in micro-optical. Owing to liquid surface tension, droplet resonators possess nearly perfect spherical geometry and exceptionally smooth surfaces that prompt more and more meritorious applications to be exploit. Herein, we survey two typical operation methods of the droplet resonators, passive and active droplet resonator. Besides, droplet applications as high-performance lasers and sensors have been discussed. Although these applications have brought us tremendous value, the research for droplet resonators are still in its infancy, added potential application and intrinsic investigation of the droplet resonators should be developed in the future work.

  18. Nonlinear resonance

    NASA Astrophysics Data System (ADS)

    Kevorkian, J.

    This report discusses research in the area of slowly varying nonlinear oscillatory systems. Some of the topics discussed are as follows: adiabatic invariants and transient resonance in very slowly varying Hamiltonian systems; sustained resonance in very slowly varying Hamiltonian systems; free-electron lasers with very slow wiggler taper; and bursting oscillators.

  19. Nonlinear resonance

    NASA Astrophysics Data System (ADS)

    Kevorkian, J.; Pernarowski, Mark; Bosley, David L.

    1990-04-01

    The subjects discussed are: transient and sustained resonance for systems with very slowly varying parameters; free electron lasers with very slow wiggler taper; and bursting oscillations in biological systems. Plans are discussed for: FEL applications; transient and sustained resonance; and bursting oscillations.

  20. Noise-exploitation and adaptation in neuromorphic sensors

    NASA Astrophysics Data System (ADS)

    Hindo, Thamira; Chakrabartty, Shantanu

    2012-04-01

    Even though current micro-nano fabrication technology has reached integration levels where ultra-sensitive sensors can be fabricated, the sensing performance (resolution per joule) of synthetic systems are still orders of magnitude inferior to those observed in neurobiology. For example, the filiform hairs in crickets operate at fundamental limits of noise; auditory sensors in a parasitoid fly can overcome fundamental limitations to precisely localize ultra-faint acoustic signatures. Even though many of these biological marvels have served as inspiration for different types of neuromorphic sensors, the main focus these designs have been to faithfully replicate the biological functionalities, without considering the constructive role of "noise". In man-made sensors device and sensor noise are typically considered as a nuisance, where as in neurobiology "noise" has been shown to be a computational aid that enables biology to sense and operate at fundamental limits of energy efficiency and performance. In this paper, we describe some of the important noise-exploitation and adaptation principles observed in neurobiology and how they can be systematically used for designing neuromorphic sensors. Our focus will be on two types of noise-exploitation principles, namely, (a) stochastic resonance; and (b) noise-shaping, which are unified within our previously reported framework called Σ▵ learning. As a case-study, we describe the application of Σ▵ learning for the design of a miniature acoustic source localizer whose performance matches that of its biological counterpart(Ormia Ochracea).

  1. Exploitation in International Paid Surrogacy Arrangements

    PubMed Central

    Wilkinson, Stephen

    2015-01-01

    Abstract Many critics have suggested that international paid surrogacy is exploitative. Taking such concerns as its starting point, this article asks: (1) how defensible is the claim that international paid surrogacy is exploitative and what could be done to make it less exploitative? (2) In the light of the answer to (1), how strong is the case for prohibiting it? Exploitation could in principle be dealt with by improving surrogates' pay and conditions. However, doing so may exacerbate problems with consent. Foremost amongst these is the argument that surrogates from economically disadvantaged countries cannot validly consent because their background circumstances are coercive. Several versions of this argument are examined and I conclude that at least one has some merit. The article's overall conclusion is that while ethically there is something to be concerned about, paid surrogacy is in no worse a position than many other exploitative commercial transactions which take place against a backdrop of global inequality and constrained options, such as poorly‐paid and dangerous construction work. Hence, there is little reason to single surrogacy out for special condemnation. On a policy level, the case for prohibiting international commercial surrogacy is weak, despite legitimate concerns about consent and background poverty. PMID:27471338

  2. Resonant Tunneling Spin Pump

    NASA Technical Reports Server (NTRS)

    Ting, David Z.

    2007-01-01

    The resonant tunneling spin pump is a proposed semiconductor device that would generate spin-polarized electron currents. The resonant tunneling spin pump would be a purely electrical device in the sense that it would not contain any magnetic material and would not rely on an applied magnetic field. Also, unlike prior sources of spin-polarized electron currents, the proposed device would not depend on a source of circularly polarized light. The proposed semiconductor electron-spin filters would exploit the Rashba effect, which can induce energy splitting in what would otherwise be degenerate quantum states, caused by a spin-orbit interaction in conjunction with a structural-inversion asymmetry in the presence of interfacial electric fields in a semiconductor heterostructure. The magnitude of the energy split is proportional to the electron wave number. Theoretical studies have suggested the possibility of devices in which electron energy states would be split by the Rashba effect and spin-polarized currents would be extracted by resonant quantum-mechanical tunneling.

  3. Acoustic Resonators

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2012-11-01

    Recently my collection of historical physics teaching apparatus was given a group of 19th-century tuning forks on resonant boxes. Figure 1 shows the smallest fork sitting on the largest one. The large tuning fork oscillates at 128 Hz and has a resonator that is 57.9 cm long. The small fork has a frequency 10 times higher, but its resonator has a length of 11.0 cm instead of the 5.8 cm that simple scaling would suggest. How is this possible?

  4. Preventing the Sexual Exploitation of Children

    MedlinePlus

    ... a person in a position of trust or responsibility living in their own community. But there are steps that need to be taken. When taken they could lead to a reduction in the incidence of sexual exploitation, an improvement in how we protect our children from this scourge, and caring and ...

  5. Exploiting a natural auxotrophy for genetic selection.

    PubMed

    Ramage, Elizabeth; Gallagher, Larry; Manoil, Colin

    2012-08-01

    We exploited the natural histidine auxotrophy of Francisella species to develop hisD (encodes histidinol dehydrogenase) as a positive selection marker. A shuttle plasmid (pBR103) carrying Escherichia coli hisD and designed for cloning of PCR fragments replicated in both attenuated and highly virulent Francisella strains. During this work, we formulated a simplified defined growth medium for Francisella novicida.

  6. Child Exploitation: Some Pieces of the Puzzle.

    ERIC Educational Resources Information Center

    Rohlader, Dorothy

    The report addresses the status in North Carolina and in the nation of child exploitation. Legislative and judicial backgrounds of child pornography and child prostitution are reviewed, and difficulties in obtaining statistical data are noted. Law enforcement issues in pornography are cited, and suggestions for further legislation regarding child…

  7. User interface development for semiautomated imagery exploitation

    NASA Astrophysics Data System (ADS)

    O'Connor, R. P.; Bohling, Edward H.

    1991-08-01

    Operational reconnaissance technical organizations are burdened by greatly increasing workloads due to expanding capabilities for collection and delivery of large-volume near-real- time multisensor/multispectral softcopy imagery. Related to the tasking of reconnaissance platforms to provide the imagery are more stringent timelines for exploiting the imagery in response to the rapidly changing threat environment being monitored. The development of a semi-automated softcopy multisensor image exploitation capability is a critical step toward integrating existing advanced image processing techniques in conjunction with appropriate intelligence and cartographic data for next-generation image exploitation systems. This paper discusses the results of a recent effort to develop computer-assisted aids for the image analyst (IA) in order to rapidly and accurately exploit multispectral/multisensor imagery in combination with intelligence support data and cartographic information for the purpose of target detection and identification. A key challenge of the effort was to design and implement an effective human-computer interface that would satisfy any generic IA task and readily accommodate the needs of a broad range of IAs.

  8. Geothermal energy exploitation in New Zealand

    SciTech Connect

    Elder, J.W.

    1980-01-01

    The essential factors, human and technical, which control the operation of geothermal systems, particularly those which allow prediction of behavior during and after exploitation, are sketched. The strategy and co-ordination involved in using New Zealand's geothermal resources for power production are considered. The broader aspects of the technical matters involved in the design of the parasitic plant reservoir system are described. (MHR)

  9. A 64 MHz half-birdcage resonator for clinical imaging

    NASA Astrophysics Data System (ADS)

    Ballon, D.; Graham, M. C.; Miodownik, S.; Koutcher, J. A.

    A radiofrequency resonator whose normal modes correspond to those of a ladder network of finite length is described. When formed into a semicylindrical geometry, the lowest frequency mode of the resulting "half-birdcage" resonator yields a B1 distribution which can be exploited for imaging.

  10. Trolling may intensify exploitation in crappie fisheries

    USGS Publications Warehouse

    Meals, K. O.; Dunn, A. W.; Miranda, Leandro E.

    2012-01-01

    In some parts of the USA, anglers targeting crappies Pomoxis spp. are transitioning from mostly stationary angling with a single pole around submerged structures to using multiple poles while drifting with the wind or under power. This shift in fishing methods could result in a change in catch efficiency, possibly increasing exploitation rates to levels that would be of concern to managers. We studied the catch statistics of anglers fishing while trolling with multiple poles (trollers) and those fishing with single poles (polers) in Mississippi reservoirs. Specifically, we tested whether (1) various catch statistics differed between trollers and polers, (2) catch rates of trollers were related to the number of poles fished, and (3) trollers could raise exploitation rates to potentially unsustainable levels. Results showed that participation in the crappie fisheries was about equally split between polers and trollers. In spring, 90% of crappie anglers were polers; in summer, 85% of crappie anglers were trollers. The size of harvested crappies was similar for the two angler groups, but the catch per hour was almost three times higher for trollers than for polers. Catch rates by trollers were directly correlated to the number of poles fished, although the relationship flattened as the number of poles increased. The average harvest rate for one troller fishing with three poles was similar to the harvest rate obtained by one poler. Simulations predicted that at the existing mix of about 50% polers and 50% trollers and with no restrictions on the number of poles used by trollers, exploitation of crappies is about 1.3 times higher than that in a polers-only fishery; under a scenario in which 100% of crappie anglers were trollers, exploitation was forecasted to increase to about 1.7 times the polers-only rate. The efficiency of trolling for crappies should be of concern to fishery managers because crappie fisheries are mostly consumptive and may increase exploitation

  11. Investigating electrical resonance in eddy-current array probes

    NASA Astrophysics Data System (ADS)

    Hughes, R.; Fan, Y.; Dixon, S.

    2016-02-01

    The sensitivity enhancing effects of eddy-current testing at frequencies close to electrical resonance are explored. Var-ied techniques exploiting the phenomenon, dubbed near electrical resonance signal enhancement (NERSE), were experimentally investigated to evaluate its potential exploitation for other interesting applications in aerospace materials, in particular its potential for boosting the sensitivity of standard ECT measurements. Methods for setting and controlling the typically unstable resonant frequencies of such systems are discussed. This research is funded by the EPSRC, via the Research Centre for Non-Destructive Evaluation RCNDE, and Rolls-Royce plc.

  12. Intelligence, mapping, and geospatial exploitation system (IMAGES)

    NASA Astrophysics Data System (ADS)

    Moellman, Dennis E.; Cain, Joel M.

    1998-08-01

    This paper provides further detail to one facet of the battlespace visualization concept described in last year's paper Battlespace Situation Awareness for Force XXI. It focuses on the National Imagery and Mapping Agency (NIMA) goal to 'provide customers seamless access to tailorable imagery, imagery intelligence, and geospatial information.' This paper describes Intelligence, Mapping, and Geospatial Exploitation System (IMAGES), an exploitation element capable of CONUS baseplant operations or field deployment to provide NIMA geospatial information collaboratively into a reconnaissance, surveillance, and target acquisition (RSTA) environment through the United States Imagery and Geospatial Information System (USIGS). In a baseplant CONUS setting IMAGES could be used to produce foundation data to support mission planning. In the field it could be directly associated with a tactical sensor receiver or ground station (e.g. UAV or UGV) to provide near real-time and mission specific RSTA to support mission execution. This paper provides IMAGES functional level design; describes the technologies, their interactions and interdependencies; and presents a notional operational scenario to illustrate the system flexibility. Using as a system backbone an intelligent software agent technology, called Open Agent ArchitectureTM (OAATM), IMAGES combines multimodal data entry, natural language understanding, and perceptual and evidential reasoning for system management. Configured to be DII COE compliant, it would utilize, to the extent possible, COTS applications software for data management, processing, fusion, exploitation, and reporting. It would also be modular, scaleable, and reconfigurable. This paper describes how the OAATM achieves data synchronization and enables the necessary level of information to be rapidly available to various command echelons for making informed decisions. The reasoning component will provide for the best information to be developed in the timeline

  13. Tribal children are most exploited - UNICEF.

    PubMed

    A workshop sponsored by the UN Children's Fund in the Philippines examined the status of the children of indigenous people and found that exploitation of the assets of indigenous people in the name of development has resulted in social inequalities that have damaged the indigenous children. As examples of the disregard for the human rights of the children, participants cited projects in Davao, Boracay, and Benguet that have displaced native children. These include mining schemes that have "raped" ancestral lands, large-scale agricultural enterprises, promotion of tourism, and creation of hydroelectric dams. The children rarely benefit at all from any of these projects as their families are moved from a position of isolated independence to one of exploited dependence. Social changes accompanying development ruin traditional culture without providing a better or even similar basis of existence.

  14. Multiquark resonances

    DOE PAGES

    Esposito, A.; Pilloni, A.; Polosa, Antonio D.

    2016-12-02

    Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties have been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical models, like the absence of selection rules limiting the number of states predicted, motivate new directions in model building.more » Lastly, data are reviewed going through all of the observed resonances with particular attention to their common features and the purpose of providing a starting point to further research.« less

  15. Multiquark resonances

    SciTech Connect

    Esposito, A.; Pilloni, A.; Polosa, Antonio D.

    2016-12-02

    Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties have been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical models, like the absence of selection rules limiting the number of states predicted, motivate new directions in model building. Lastly, data are reviewed going through all of the observed resonances with particular attention to their common features and the purpose of providing a starting point to further research.

  16. Multiquark resonances

    NASA Astrophysics Data System (ADS)

    Esposito, A.; Pilloni, A.; Polosa, A. D.

    2017-01-01

    Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties have been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical models, like the absence of selection rules limiting the number of states predicted, motivate new directions in model building. Data are reviewed going through all of the observed resonances with particular attention to their common features and the purpose of providing a starting point to further research.

  17. Macropinocytosis Exploitation by Cancers and Cancer Therapeutics

    PubMed Central

    Ha, Kevin D.; Bidlingmaier, Scott M.; Liu, Bin

    2016-01-01

    Macropinocytosis has long been known as a primary method for cellular intake of fluid-phase and membrane-bound bulk cargo. This review seeks to re-examine the latest studies to emphasize how cancers exploit macropinocytosis to further their tumorigenesis, including details in how macropinocytosis can be adapted to serve diverse functions. Furthermore, this review will also cover the latest endeavors in targeting macropinocytosis as an avenue for novel therapeutics. PMID:27672367

  18. Exploiting Data Similarity to Reduce Memory Footprints

    DTIC Science & Technology

    2011-01-01

    addresses for each of these categories. Figure 10 shows the state machine that we use to categorize and to process groups of pages once our interrupt...handler observes that memory usage exceeds the threshold. This state machine uses MergePendingPages to perform the merging, which uses mmap, mremap...exploit these techniques to detect when identical pages diverge. Waldspurger [23] incorporated searching for identical data in virtual machines (VMs

  19. DANDRUFF: THE MOST COMMERCIALLY EXPLOITED SKIN DISEASE

    PubMed Central

    Ranganathan, S; Mukhopadhyay, T

    2010-01-01

    The article discuss in detail about the prevalence, pathophysiology, clinical manifestations of dandruff including the etio-pathology. The article also discusses in detail about various treatment methods available for dandruff. The status of dandruff being amphibious – a disease/disorder, and relatively less medical intervention is sought after for the treatment, dandruff is the most commercially exploited skin and scalp disorder/disease by personal care industries. PMID:20606879

  20. Tunable Magnetic Resonance in Microwave Spintronics Devices

    NASA Technical Reports Server (NTRS)

    Chen, Yunpeng; Fan, Xin; Xie, Yungsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

    2015-01-01

    Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe-based tunable microwave spintronics devices, which is 10X higher than conventional methods.

  1. Tunable Magnetic Resonance in Microwave Spintronics Devices

    NASA Technical Reports Server (NTRS)

    Chen, Yunpeng; Fan, Xin; Xie, Yunsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

    2015-01-01

    Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe based tunable microwave spintronics devices, which is 10X higher than conventional methods.

  2. Laser Resonator

    NASA Technical Reports Server (NTRS)

    Harper, L. L. (Inventor)

    1983-01-01

    An optical resonator cavity configuration has a unitary mirror with oppositely directed convex and concave reflective surfaces disposed into one fold and concertedly reversing both ends of a beam propagating from a laser rod disposed between two total internal reflection prisms. The optical components are rigidly positioned with perpendicularly crossed virtual rooflines by a compact optical bed. The rooflines of the internal reflection prisms, are arranged perpendicularly to the axis of the laser beam and to the optical axes of the optical resonator components.

  3. Smoking automaticity and tolerance moderate brain activation during explore-exploit behavior

    PubMed Central

    Addicott, Merideth A.; Pearson, John M.; Froeliger, Brett; Platt, Michael L.; McClernon, F. Joseph

    2014-01-01

    The adaptive trade-off between exploration and exploitation is a key component in models of reinforcement learning. Over the past decade, these models have been applied to the study of reward-seeking behavior. Drugs of addiction induce reward-seeking behavior and modify its underlying neurophysiological processes. These neurophysiological changes may underlie a behavioral shift from a flexible, exploratory mode to a focused, exploitative mode, which precedes the development of inflexible, habitual drug use. The goal of this study was to investigate the relationship between explore/exploit behavior and drug addiction by examining the neural correlates of this behavior in cigarette smokers. Participants (n = 22) with a range of smoking behaviors completed a smoking dependence motives questionnaire and played a 6-armed bandit task while undergoing functional magnetic resonance imaging (fMRI). Exploratory behavior produced greater activation in the bilateral superior parietal and bilateral frontal cortices than exploitative behavior. Exploitative behavior produced greater activation in the bilateral superior and middle temporal gyri than exploratory behavior. fMRI data and orthogonalized smoking dependence motive scores were entered into multiple linear regression analyses. After controlling for nicotine tolerance, smoking automaticity positively correlated with activation in the same bilateral parietal regions preferentially activated by exploratory choices. These preliminary results link smoking dependence motives to variation in the neural processes that mediate exploratory decision making. PMID:25453166

  4. Autostereogram resonators

    NASA Astrophysics Data System (ADS)

    Leavey, Sean; Rae, Katherine; Murray, Adam; Courtial, Johannes

    2012-09-01

    Autostereograms, or "Magic Eye" pictures, are repeating patterns designed to give the illusion of depth. Here we discuss optical resonators that create light patterns which, when viewed from a suitable position by a monocular observer, are autostereograms of the three-dimensional shape of one of the mirror surfaces.

  5. Exploitation of subsea gas hydrate reservoirs

    NASA Astrophysics Data System (ADS)

    Janicki, Georg; Schlüter, Stefan; Hennig, Torsten; Deerberg, Görge

    2016-04-01

    Natural gas hydrates are considered to be a potential energy resource in the future. They occur in permafrost areas as well as in subsea sediments and are stable at high pressure and low temperature conditions. According to estimations the amount of carbon bonded in natural gas hydrates worldwide is two times larger than in all known conventional fossil fuels. Besides technical challenges that have to be overcome climate and safety issues have to be considered before a commercial exploitation of such unconventional reservoirs. The potential of producing natural gas from subsea gas hydrate deposits by various means (e.g. depressurization and/or injection of carbon dioxide) is numerically studied in the frame of the German research project »SUGAR«. The basic mechanisms of gas hydrate formation/dissociation and heat and mass transport in porous media are considered and implemented into a numerical model. The physics of the process leads to strong non-linear couplings between hydraulic fluid flow, hydrate dissociation and formation, hydraulic properties of the sediment, partial pressures and seawater solution of components and the thermal budget of the system described by the heat equation. This paper is intended to provide an overview of the recent development regarding the production of natural gas from subsea gas hydrate reservoirs. It aims at giving a broad insight into natural gas hydrates and covering relevant aspects of the exploitation process. It is focused on the thermodynamic principles and technological approaches for the exploitation. The effects occurring during natural gas production within hydrate filled sediment layers are identified and discussed by means of numerical simulation results. The behaviour of relevant process parameters such as pressure, temperature and phase saturations is described and compared for different strategies. The simulations are complemented by calculations for different safety relevant problems.

  6. Algorithms exploiting ultrasonic sensors for subject classification

    NASA Astrophysics Data System (ADS)

    Desai, Sachi; Quoraishee, Shafik

    2009-09-01

    Proposed here is a series of techniques exploiting micro-Doppler ultrasonic sensors capable of characterizing various detected mammalian targets based on their physiological movements captured a series of robust features. Employed is a combination of unique and conventional digital signal processing techniques arranged in such a manner they become capable of classifying a series of walkers. These processes for feature extraction develops a robust feature space capable of providing discrimination of various movements generated from bipeds and quadrupeds and further subdivided into large or small. These movements can be exploited to provide specific information of a given signature dividing it in a series of subset signatures exploiting wavelets to generate start/stop times. After viewing a series spectrograms of the signature we are able to see distinct differences and utilizing kurtosis, we generate an envelope detector capable of isolating each of the corresponding step cycles generated during a walk. The walk cycle is defined as one complete sequence of walking/running from the foot pushing off the ground and concluding when returning to the ground. This time information segments the events that are readily seen in the spectrogram but obstructed in the temporal domain into individual walk sequences. This walking sequence is then subsequently translated into a three dimensional waterfall plot defining the expected energy value associated with the motion at particular instance of time and frequency. The value is capable of being repeatable for each particular class and employable to discriminate the events. Highly reliable classification is realized exploiting a classifier trained on a candidate sample space derived from the associated gyrations created by motion from actors of interest. The classifier developed herein provides a capability to classify events as an adult humans, children humans, horses, and dogs at potentially high rates based on the tested sample

  7. Art Therapy Exhibitions: Exploitation or Advocacy?

    PubMed

    Davis, Terri

    2017-01-01

    Promoting awareness of human trafficking by sharing trauma survivors' art and summaries of their life stories suggests ethical complexities that have been typically neglected by bioethicists. Although these survivors voluntarily share the objects they created during art therapy sessions, they are still at risk of harm, including further exploitation, due to their vulnerability, high rates of victim sensitivity, and the mental health consequences of their traumatic experiences. While some argue that the benefits of sublimation and art therapy for human trafficking survivors make sharing their art worth the risk, anti-trafficking organizations and supporters of such art exhibitions have responsibilities to be trauma informed.

  8. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    SciTech Connect

    Tomimatsu, Toru Shirai, Shota; Hashimoto, Katsushi Sato, Ken; Hirayama, Yoshiro

    2015-08-15

    Electric-field-induced nuclear resonance (NER: nuclear electric resonance) involving quantum Hall states (QHSs) was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs.

  9. Competing Discourses about Youth Sexual Exploitation in Canadian News Media.

    PubMed

    Saewyc, Elizabeth M; Miller, Bonnie B; Rivers, Robert; Matthews, Jennifer; Hilario, Carla; Hirakata, Pam

    2013-10-01

    Media holds the power to create, maintain, or break down stigmatizing attitudes, which affect policies, funding, and services. To understand how Canadian news media depicts the commercial sexual exploitation of children and youth, we examined 835 Canadian newspaper articles from 1989-2008 using a mixed methods critical discourse analysis approach, comparing representations to existing research about sexually exploited youth. Despite research evidence that equal rates of boys and girls experience exploitation, Canadian news media depicted exploited youth predominantly as heterosexual girls, and described them alternately as victims or workers in a trade, often both in the same story. News media mentioned exploiters far less often than victims, and portrayed them almost exclusively as male, most often called 'customers' or 'consumers,' and occasionally 'predators'; in contrast, research has documented the majority of sexually exploited boys report female exploiters. Few news stories over the past two decades portrayed the diversity of victims, perpetrators, and venues of exploitation reported in research. The focus on victims but not exploiters helps perpetuate stereotypes of sexual exploitation as business or a 'victimless crime,' maintains the status quo, and blurs responsibility for protecting youth under the UN Convention on the Rights of the Child. Health care providers and researchers can be advocates for accuracy in media coverage about sexual exploitation; news reporters and editors should focus on exploiters more than victims, draw on existing research evidence to avoid perpetuating stereotypes, and use accurate terms, such as commercial sexual exploitation, rather than terms related to business or trade.

  10. Compressed sensing MRI exploiting complementary dual decomposition.

    PubMed

    Park, Suhyung; Park, Jaeseok

    2014-04-01

    Compressed sensing (CS) MRI exploits the sparsity of an image in a transform domain to reconstruct the image from incoherently under-sampled k-space data. However, it has been shown that CS suffers particularly from loss of low-contrast image features with increasing reduction factors. To retain image details in such degraded experimental conditions, in this work we introduce a novel CS reconstruction method exploiting feature-based complementary dual decomposition with joint estimation of local scale mixture (LSM) model and images. Images are decomposed into dual block sparse components: total variation for piecewise smooth parts and wavelets for residuals. The LSM model parameters of residuals in the wavelet domain are estimated and then employed as a regional constraint in spatially adaptive reconstruction of high frequency subbands to restore image details missing in piecewise smooth parts. Alternating minimization of the dual image components subject to data consistency is performed to extract image details from residuals and add them back to their complementary counterparts while the LSM model parameters and images are jointly estimated in a sequential fashion. Simulations and experiments demonstrate the superior performance of the proposed method in preserving low-contrast image features even at high reduction factors.

  11. Large size space construction for space exploitation

    NASA Astrophysics Data System (ADS)

    Kondyurin, Alexey

    2016-07-01

    Space exploitation is impossible without large space structures. We need to make sufficient large volume of pressurized protecting frames for crew, passengers, space processing equipment, & etc. We have to be unlimited in space. Now the size and mass of space constructions are limited by possibility of a launch vehicle. It limits our future in exploitation of space by humans and in development of space industry. Large-size space construction can be made with using of the curing technology of the fibers-filled composites and a reactionable matrix applied directly in free space. For curing the fabric impregnated with a liquid matrix (prepreg) is prepared in terrestrial conditions and shipped in a container to orbit. In due time the prepreg is unfolded by inflating. After polymerization reaction, the durable construction can be fitted out with air, apparatus and life support systems. Our experimental studies of the curing processes in the simulated free space environment showed that the curing of composite in free space is possible. The large-size space construction can be developed. A project of space station, Moon base, Mars base, mining station, interplanet space ship, telecommunication station, space observatory, space factory, antenna dish, radiation shield, solar sail is proposed and overviewed. The study was supported by Humboldt Foundation, ESA (contract 17083/03/NL/SFe), NASA program of the stratospheric balloons and RFBR grants (05-08-18277, 12-08-00970 and 14-08-96011).

  12. Exploiting Allee effects for managing biological invasions.

    PubMed

    Tobin, Patrick C; Berec, Luděk; Liebhold, Andrew M

    2011-06-01

    Biological invasions are a global and increasing threat to the function and diversity of ecosystems. Allee effects (positive density dependence) have been shown to play an important role in the establishment and spread of non-native species. Although Allee effects can be considered a bane in conservation efforts, they can be a benefit in attempts to manage non-native species. Many biological invaders are subject to some form of an Allee effect, whether due to a need to locate mates, cooperatively feed or reproduce or avoid becoming a meal, yet attempts to highlight the specific exploitation of Allee effects in biological invasions are surprisingly unprecedented. In this review, we highlight current strategies that effectively exploit an Allee effect, and propose novel means by which Allee effects can be manipulated to the detriment of biological invaders. We also illustrate how the concept of Allee effects can be integral in risk assessments and in the prioritization of resources allocated to manage non-native species, as some species beset by strong Allee effects could be less successful as invaders. We describe how tactics that strengthen an existing Allee effect or create new ones could be used to manage biological invasions more effectively.

  13. Compressed Sensing MR Image Reconstruction Exploiting TGV and Wavelet Sparsity

    PubMed Central

    Du, Huiqian; Han, Yu; Mei, Wenbo

    2014-01-01

    Compressed sensing (CS) based methods make it possible to reconstruct magnetic resonance (MR) images from undersampled measurements, which is known as CS-MRI. The reference-driven CS-MRI reconstruction schemes can further decrease the sampling ratio by exploiting the sparsity of the difference image between the target and the reference MR images in pixel domain. Unfortunately existing methods do not work well given that contrast changes are incorrectly estimated or motion compensation is inaccurate. In this paper, we propose to reconstruct MR images by utilizing the sparsity of the difference image between the target and the motion-compensated reference images in wavelet transform and gradient domains. The idea is attractive because it requires neither the estimation of the contrast changes nor multiple times motion compensations. In addition, we apply total generalized variation (TGV) regularization to eliminate the staircasing artifacts caused by conventional total variation (TV). Fast composite splitting algorithm (FCSA) is used to solve the proposed reconstruction problem in order to improve computational efficiency. Experimental results demonstrate that the proposed method can not only reduce the computational cost but also decrease sampling ratio or improve the reconstruction quality alternatively. PMID:25371704

  14. Energy harvesting from human motion: exploiting swing and shock excitations

    NASA Astrophysics Data System (ADS)

    Ylli, K.; Hoffmann, D.; Willmann, A.; Becker, P.; Folkmer, B.; Manoli, Y.

    2015-02-01

    Modern compact and low power sensors and systems are leading towards increasingly integrated wearable systems. One key bottleneck of this technology is the power supply. The use of energy harvesting techniques offers a way of supplying sensor systems without the need for batteries and maintenance. In this work we present the development and characterization of two inductive energy harvesters which exploit different characteristics of the human gait. A multi-coil topology harvester is presented which uses the swing motion of the foot. The second device is a shock-type harvester which is excited into resonance upon heel strike. Both devices were modeled and designed with the key constraint of device height in mind, in order to facilitate the integration into the shoe sole. The devices were characterized under different motion speeds and with two test subjects on a treadmill. An average power output of up to 0.84 mW is achieved with the swing harvester. With a total device volume including the housing of 21 cm3 a power density of 40 μW cm-3 results. The shock harvester generates an average power output of up to 4.13 mW. The power density amounts to 86 μW cm-3 for the total device volume of 48 cm3. Difficulties and potential improvements are discussed briefly.

  15. Stochastic resonance in nanomechanical systems

    NASA Astrophysics Data System (ADS)

    Badzey, Robert L.

    The phenomenon of stochastic resonance is a counter-intuitive one: adding noise to a noisy nonlinear system under the influence of a modulation results in coherent behavior. The signature of the effect is a resonance in the signal-to-noise ratio of the response over a certain range of noise power; this behavior is absent if either the modulation or the noise are absent. Stochastic resonance has attracted considerable interest over the past several decades, having been seen in a great number of physical and biological systems. Here, observation of stochastic resonance is reported for nanomechanical systems consisting of a doubly-clamped beam resonators fabricated from single-crystal silicon. Such oscillators have been found to display nonlinear and bistable behavior under the influence of large driving forces. This bistability is exploited to produce a controllable nanomechanical switch, a device that may be used as the basis for a new generation of computational memory elements. These oscillators possess large intrinsic resonance frequencies (MHz range or higher) due to their small size and relatively high stiffness; thus they have the potential to rival the current state-of-the-art of electronic and magnetic storage technologies. This small size also allows them to be packed in densities which meet or exceed the superparamagnetic limit for magnetic storage media of 100 GB/in2. Two different doubly-clamped beams were cooled to low temperatures (300 mK--4 K), and excited with a magnetomotive technique. They were driven into the nonlinear response regime, and then modulated to induce switching between their bistable states. When the modulation was reduced, the switching died out. Application of noise, either with an external broadband source or via an increase in temperature, resulted in a distinct resonance in the signal-to-noise ratio. Aside from establishing the phenomenon of stochastic resonance in yet another physical system, the observation of this effect has

  16. Exploiting surface plasmon scattering on optical fibers

    NASA Astrophysics Data System (ADS)

    Klantsataya, Elizaveta; François, Alexandre; Sciacca, Beniamino; Zuber, Agnieszka; Ebendorff-Heidepriem, Heike; Hoffmann, Peter; Monro, Tanya M.

    2016-12-01

    For decades Surface Plasmon Resonance (SPR) has been one of the corner stones of label free biosensing with a wide range of architectures including optical fiber based SPR. Traditionally, the resonance is monitored through reflectivity measurements at a single wavelength as a function of the incident angle in a standard Kretschmann configuration, or transmission of broadband light through an optical fiber. In both cases, SPR is inferred through optical losses. An alternative approach is to use SPR scattering induced by rough metallic coatings, enabling to turn an intrinsically nonradiative process into a radiative one. As a result, the SPR signal corresponding to the resonance can be seen as light at specific wavelengths being re-emitted by the rough metallic coating. Here, we present results we have achieved using SPR scattering as an alternative approach for optical fiber based plasmonic sensors. Although the use of a rough metallic coating induces some inherent limitations, such as a lower resolution, the architectural advantages and simplicity of the approach offer additional opportunities, such as multiplexing and self-referencing, which are not possible otherwise with a single fiber SPR sensor. A way to overcome the lower resolution that involves the use of microstructured optical fibers, as well as a new perspective on a complementary application, such as Metal Enhanced Fluorescence, which greatly benefits from SPR scattering, will be presented.

  17. Humanitarian mine detection by acoustic resonance

    SciTech Connect

    Kercel, S.W.

    1998-03-01

    The JASON Committee at MITRE Corp. was tasked by DARPA to inquire into suitable technologies for humanitarian mine detection. Acoustic resonance was one of the very few technologies that the JASONs determined might be promising for the task, but was as yet unexplored at the time that they conducted their inquiry. The objective of this Seed Money investigation into acoustic resonance was to determine if it would be feasible to use acoustic resonance to provide an improvement to present methods for humanitarian mine detection. As detailed in this report, acoustic resonance methods do not appear to be feasible for this task. Although acoustic resonant responses are relatively easy to detect when they exist, they are very difficult to excite by the non-contact means that must be used for buried objects. Despite many different attempts, this research did not discover any practical means of using sound to excite resonant responses in objects known to have strong resonances. The shaker table experiments did see an effect that might be attributable to the resonance of the object under test, but the effect was weak, and exploited the a priori knowledge of the resonant frequency of the object under test to distinguish it from the background. If experiments that used objects known to have strong acoustic resonances produced such marginal results, this does not seem to be a practical method to detect objects with weak resonances or non-existent resonances. The results of this work contribute to the ORNL countermine initiative. ORNL is exploring several unconventional mine detection technologies, and is proposed to explore others. Since this research has discovered some major pitfalls in non-metallic mine detection, this experience will add realism to other strategies proposed for mine detection technologies. The experiment provided hands-on experience with inert plastic mines under field conditions, and gives ORNL additional insight into the problems of developing practical

  18. Biosensing by WGM Microspherical Resonators

    PubMed Central

    Righini, Giancarlo C.; Soria, Silvia

    2016-01-01

    Whispering gallery mode (WGM) microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed. PMID:27322282

  19. Early Warning and Prediction of Interest Attacks and Exploits

    DTIC Science & Technology

    2005-09-01

    EARLY WARNING AND PREDICTION OF INTERNET ATTACKS AND EXPLOITS THESIS Brian P. Zeitz... EARLY WARNING AND PREDICTION OF INTERNET ATTACKS AND EXPLOITS THESIS Presented to the Faculty Department of Electrical and Computer...RELEASE; DISTRIBUTION UNLIMITED iv AFIT/GIA/ENG/05-06 EARLY WARNING AND PREDICTION OF INTERNET ATTACKS AND EXPLOITS

  20. Ultrasonic resonator for manipulation of bacteria

    NASA Astrophysics Data System (ADS)

    Schwarz, T.; Dual, J.

    2012-05-01

    Ultrasonic manipulation is a contactless and gentle method to manipulate a large number of particles. The method presented here exploits the advantage to simultaneously move bacteria away from a surface by means of acoustic radiation forces. The device for the manipulation consists of five layers (transducer, epoxy adhesive layer, carrier, fluid, reflector), stacked like a conventional planar resonator. The resonator behavior was simulated using the transfer matrix method (TMM). Validation of the model was realized with admittance measurements performed over a wide frequency range (100 kHz - 16 MHz). The TMM-model was used to optimize frequency, layer thickness and material of the resonator in order to find a combination with a high force potential gradient pointing away from the reflector surface into the fluid. The resonator has been experimentally tested with polystyrene particles (1 μm in diameter) which revealed a good matching with the TMM-model. First preliminary tests with Salmonella Thyphimurium have been done.

  1. Explosives Detection: Exploitation of the Physical Signatures

    NASA Astrophysics Data System (ADS)

    Atkinson, David

    2010-10-01

    Explosives based terrorism is an ongoing threat that is evolving with respect to implementation, configuration and materials used. There are a variety of devices designed to detect explosive devices, however, each technology has limitations and operational constraints. A full understanding of the signatures available for detection coupled with the array of detection choices can be used to develop a conceptual model of an explosives screening operation. Physics based sensors provide a robust approach to explosives detection, typically through the identification of anomalies, and are currently used for screening in airports around the world. The next generation of detectors for explosives detection will need to be more sensitive and selective, as well as integrate seamlessly with devices focused on chemical signatures. An appreciation for the details of the physical signature exploitation in cluttered environments with time, space, and privacy constraints is necessary for effective explosives screening of people, luggage, cargo, and vehicles.

  2. Digital video steganalysis exploiting collusion sensitivity

    NASA Astrophysics Data System (ADS)

    Budhia, Udit; Kundur, Deepa

    2004-09-01

    In this paper we present an effective steganalyis technique for digital video sequences based on the collusion attack. Steganalysis is the process of detecting with a high probability and low complexity the presence of covert data in multimedia. Existing algorithms for steganalysis target detecting covert information in still images. When applied directly to video sequences these approaches are suboptimal. In this paper, we present a method that overcomes this limitation by using redundant information present in the temporal domain to detect covert messages in the form of Gaussian watermarks. Our gains are achieved by exploiting the collusion attack that has recently been studied in the field of digital video watermarking, and more sophisticated pattern recognition tools. Applications of our scheme include cybersecurity and cyberforensics.

  3. Exploiting epigenetic vulnerabilities for cancer therapeutics.

    PubMed

    Mair, Barbara; Kubicek, Stefan; Nijman, Sebastian M B

    2014-03-01

    Epigenetic deregulation is a hallmark of cancer, and there has been increasing interest in therapeutics that target chromatin-modifying enzymes and other epigenetic regulators. The rationale for applying epigenetic drugs to treat cancer is twofold. First, epigenetic changes are reversible, and drugs could therefore be used to restore the normal (healthy) epigenetic landscape. However, it is unclear whether drugs can faithfully restore the precancerous epigenetic state. Second, chromatin regulators are often mutated in cancer, making them attractive drug targets. However, in most instances it is unknown whether cancer cells are addicted to these mutated chromatin proteins, or whether their mutation merely results in epigenetic instability conducive to the selection of secondary aberrations. An alternative incentive for targeting chromatin regulators is the exploitation of cancer-specific vulnerabilities, including synthetic lethality, caused by epigenetic deregulation. We review evidence for the hypothesis that mechanisms other than oncogene addiction are a basis for the application of epigenetic drugs, and propose future research directions.

  4. Redressing China's strategy of water resource exploitation.

    PubMed

    Ran, Lishan; Lu, Xi Xi

    2013-03-01

    China, with the confrontation of water-related problems as an element of its long history, has been investing heavily in water engineering projects over the past few decades based on the assumption that these projects can solve its water problems. However, the anticipated benefits did not really occur, or at least not as large as expected. Instead, the results involved additional frustrations, such as biodiversity losses and human-induced disasters (i.e., landslides and earthquakes). Given its inherent shortcomings, the present engineering-dominated strategy for the management of water resources cannot help solve China's water problems and achieve its goal of low-carbon transformation. Therefore, the present strategy for water resources exploitation needs to be reevaluated and redressed. A policy change to achieve better management of Chinese rivers is urgently needed.

  5. Iron and Zinc Exploitation during Bacterial Pathogenesis

    PubMed Central

    Ma, Li; Terwilliger, Austen; Maresso, Anthony W.

    2016-01-01

    Ancient bacteria originated from metal-rich environments. Billions of years of evolution directed these tiny single cell creatures to exploit the versatile properties of metals in catalyzing chemical reactions and biological responses. The result is an entire metallome of proteins that use metal co-factors to facilitate key cellular process that range from the production of energy to the replication of DNA. Two key metals in this regard are iron and zinc, both abundant on Earth but not readily accessible in a human host. Instead, pathogenic bacteria must employ clever ways to acquire these metals. In this review we describe the many elegant ways these bacteria mine, regulate, and craft the use of two key metals (iron and zinc) to build a virulence arsenal that challenges even the most sophisticated immune response. PMID:26497057

  6. If It's Resonance, What is Resonating?

    ERIC Educational Resources Information Center

    Kerber, Robert C.

    2006-01-01

    The phenomenon under the name "resonance," which, is based on the mathematical analogy between mechanical resonance and the behavior of wave functions in quantum mechanical exchange phenomena was described. The resonating system does not have a structure intermediate between those involved in the resonance, but instead a structure which is further…

  7. Are Youths' Feelings of Entitlement Always "Bad"?: Evidence for a Distinction between Exploitive and Non-Exploitive Dimensions of Entitlement

    ERIC Educational Resources Information Center

    Lessard, Jared; Greenberger, Ellen; Chen, Chuansheng; Farruggia, Susan

    2011-01-01

    Previous personality research (e.g., Campbell et al., 2004) has described the sense of entitlement as an unifactorial construct. In this study, we examined characteristics of two potential facets of entitlement: exploitive entitlement, characterized by exploitive interactions and expectations of special treatment, and non-exploitive entitlement,…

  8. Mission Exploitation Platform PROBA-V

    NASA Astrophysics Data System (ADS)

    Goor, Erwin

    2016-04-01

    VITO and partners developed an end-to-end solution to drastically improve the exploitation of the PROBA-V EO-data archive (http://proba-v.vgt.vito.be/), the past mission SPOT-VEGETATION and derived vegetation parameters by researchers, service providers and end-users. The analysis of time series of data (+1PB) is addressed, as well as the large scale on-demand processing of near real-time data. From November 2015 an operational Mission Exploitation Platform (MEP) PROBA-V, as an ESA pathfinder project, will be gradually deployed at the VITO data center with direct access to the complete data archive. Several applications will be released to the users, e.g. - A time series viewer, showing the evolution of PROBA-V bands and derived vegetation parameters for any area of interest. - Full-resolution viewing services for the complete data archive. - On-demand processing chains e.g. for the calculation of N-daily composites. - A Virtual Machine will be provided with access to the data archive and tools to work with this data, e.g. various toolboxes and support for R and Python. After an initial release in January 2016, a research platform will gradually be deployed allowing users to design, debug and test applications on the platform. From the MEP PROBA-V, access to Sentinel-2 and landsat data will be addressed as well, e.g. to support the Cal/Val activities of the users. Users can make use of powerful Web based tools and can self-manage virtual machines to perform their work on the infrastructure at VITO with access to the complete data archive. To realise this, private cloud technology (openStack) is used and a distributed processing environment is built based on Hadoop. The Hadoop ecosystem offers a lot of technologies (Spark, Yarn, Accumulo, etc.) which we integrate with several open-source components. The impact of this MEP on the user community will be high and will completely change the way of working with the data and hence open the large time series to a larger

  9. GOCE Exploitation for Moho Modeling and Applications

    NASA Astrophysics Data System (ADS)

    Sampierto, D.

    2011-07-01

    New ESA missions dedicated to the observation of the Earth from space, like the gravity-gradiometry mission GOCE and the radar altimetry mission CRYOSAT 2, foster research, among other subjects, also on inverse gravimetric problems and on the description of the nature and the geographical location of gravimetric signals. In this framework the GEMMA project (GOCE Exploitation for Moho Modeling and Applications), funded by the European Space Agency and Politecnico di Milano, aims at estimating the boundary between Earth's crust and mantle (the so called Mohorovičić discontinuity or Moho) from GOCE data in key regions of the world. In the project a solution based on a simple two layer model in spherical approximation is proposed. This inversion problem based on the linearization of the Newton's gravitational law around an approximate mean Moho surface will be solved by exploiting Wiener-Kolmogorov theory in the frequency domain where the depth of the Moho discontinuity will be treated as a random signal with a zero mean and its own covariance function. The algorithm can be applied in a numerically efficient way by using the Fast Fourier Transform. As for the gravity observations, we will consider grids of the anomalous gravitational potential and its second radial derivative at satellite altitude. In particular this will require first of all to elaborate GOCE data to obtain a local grid of the gravitational potential field and its second radial derivative and after that to separate the gravimetric signal due to the considered discontinuity from the gravitational effects of other geological structures present into the observations. The first problem can be solved by applying the so called space- wise approach to GOCE observations, while the second one can be achieved by considering a priori models and geophysical information by means of an appropriate Bayesan technique. Moreover other data such as ground gravity anomalies or seismic profiles can be combined, in an

  10. Wave energy extraction by coupled resonant absorbers.

    PubMed

    Evans, D V; Porter, R

    2012-01-28

    In this article, a range of problems and theories will be introduced that will build towards a new wave energy converter (WEC) concept, with the acronym 'ROTA' standing for resonant over-topping absorber. First, classical results for wave power absorption for WECs constrained to operate in a single degree of freedom will be reviewed and the role of resonance in their operation highlighted. Emphasis will then be placed on how the introduction of further resonances can improve power take-off characteristics by extending the range of frequencies over which the efficiency is close to a theoretical maximum. Methods for doing this in different types of WECs will be demonstrated. Coupled resonant absorbers achieve this by connecting a WEC device equipped with its own resonance (determined from a hydrodynamic analysis) to a new system having separate mass/spring/damper characteristics. It is shown that a coupled resonant effect can be realized by inserting a water tank into a WEC, and this idea forms the basis of the ROTA device. In essence, the idea is to exploit the coupling between the natural sloshing frequencies of the water in the internal tank and the natural resonance of a submerged buoyant circular cylinder device that is tethered to the sea floor, allowing a rotary motion about its axis of attachment.

  11. Analytical insights into optimality and resonance in fish swimming.

    PubMed

    Kohannim, Saba; Iwasaki, Tetsuya

    2014-03-06

    This paper provides analytical insights into the hypothesis that fish exploit resonance to reduce the mechanical cost of swimming. A simple body-fluid fish model, representing carangiform locomotion, is developed. Steady swimming at various speeds is analysed using optimal gait theory by minimizing bending moment over tail movements and stiffness, and the results are shown to match with data from observed swimming. Our analysis indicates the following: thrust-drag balance leads to the Strouhal number being predetermined based on the drag coefficient and the ratio of wetted body area to cross-sectional area of accelerated fluid. Muscle tension is reduced when undulation frequency matches resonance frequency, which maximizes the ratio of tail-tip velocity to bending moment. Finally, hydrodynamic resonance determines tail-beat frequency, whereas muscle stiffness is actively adjusted, so that overall body-fluid resonance is exploited.

  12. Exploiting fungal cell wall components in vaccines

    PubMed Central

    Levitz, Stuart M.; Huang, Haibin; Ostroff, Gary R.; Specht, Charles A.

    2014-01-01

    Innate recognition of fungi leads to strong adaptive immunity. Investigators are trying to exploit this observation in vaccine development by combining antigens with evolutionarily conserved fungal cell wall carbohydrates to induce protective responses. Best studied is β-1,3-glucan, a glycan that activates complement and is recognized by Dectin-1. Administration of antigens in association with β-1,3-glucan, either by direct conjugation or complexed in glucan particles, results in robust humoral and cellular immune responses. While the host has a host of mannose receptors, responses to fungal mannoproteins generally are amplified if cells are cooperatively stimulated with an additional danger signal such as a toll-like receptor agonist. Chitosan, a polycationic homopolymer of glucosamine manufactured by the deacetylation of chitin, is being studied as an adjuvant in DNA and protein-based vaccines. It appears particularly promising in mucosal vaccines. Finally, universal and organism-specific fungal vaccines have been formulated by conjugating fungal cell wall glycans to carrier proteins. A major challenge will be to advance these experimental findings so that at risk patients can be protected. PMID:25404118

  13. Exploiting intrinsic fluctuations to identify model parameters.

    PubMed

    Zimmer, Christoph; Sahle, Sven; Pahle, Jürgen

    2015-04-01

    Parameterisation of kinetic models plays a central role in computational systems biology. Besides the lack of experimental data of high enough quality, some of the biggest challenges here are identification issues. Model parameters can be structurally non-identifiable because of functional relationships. Noise in measured data is usually considered to be a nuisance for parameter estimation. However, it turns out that intrinsic fluctuations in particle numbers can make parameters identifiable that were previously non-identifiable. The authors present a method to identify model parameters that are structurally non-identifiable in a deterministic framework. The method takes time course recordings of biochemical systems in steady state or transient state as input. Often a functional relationship between parameters presents itself by a one-dimensional manifold in parameter space containing parameter sets of optimal goodness. Although the system's behaviour cannot be distinguished on this manifold in a deterministic framework it might be distinguishable in a stochastic modelling framework. Their method exploits this by using an objective function that includes a measure for fluctuations in particle numbers. They show on three example models, immigration-death, gene expression and Epo-EpoReceptor interaction, that this resolves the non-identifiability even in the case of measurement noise with known amplitude. The method is applied to partially observed recordings of biochemical systems with measurement noise. It is simple to implement and it is usually very fast to compute. This optimisation can be realised in a classical or Bayesian fashion.

  14. The Spanish network for Gaia Science Exploitation

    NASA Astrophysics Data System (ADS)

    Figueras, F.; Jordi, C.; Luri, X.; Torra, J.; REG Executive Committee Team; Gaia UB team

    2017-03-01

    The ''Red Española de Explotación Científica de Gaia'' (REG) continues to intensify its activities facing the imminent publication of the first and second Gaia data releases (14 September, 2016 and Q4-2017, respectively). The network, supported by the MINECO under contract Acciones de dinamizaci ´on, Redes de Excelencia (2016-2017), has as major priority the task to coordinate and support the collective activities developed by its more than 150 members. At present, REG plays a prominent role in the preparation of the Spanish community for the use of the Gaia data archive (a task lead by the Spanish team), in the work to exploit the Gaia-ESO survey collected during the last four years and in supporting the preparation of the science case and survey plan for WEAVE, the new multi-object spectrograph for the WHT at Canary Islands (commissioning, 2018). These activities are described together with the schedule of future national and international science meetings and the outreach activities being organized for the first and second Data Releases

  15. Understanding Online Child Sexual Exploitation Offenses.

    PubMed

    Ly, Thanh; Murphy, Lisa; Fedoroff, J Paul

    2016-08-01

    In the past three decades, there has been an exponential increase in the worldwide availability of Internet access and devices that are able to access online materials. This literature review investigated whether increased accessibility of Internet child pornography (CP) increases the risk of in-person child sexual exploitation. The current review found little to no evidence that availability of the Internet has increased the worldwide incidence or prevalence of in-person child sexual abuse. In fact, during the time period in which the Internet has flourished, international crime statistics have shown a steady decrease of in-person child sexual abuse. The only exception to this trend is an increase in Internet child pornography or luring offenses (e.g., Stats Can, 2014), which involves child abuse by definition. This article reviews the impact of the Internet on child sexual abuse. It also reviews the characteristics of online CP offenders. Treatment of these offenders and prevention of such offenses is also discussed.

  16. Exploiting core knowledge for visual object recognition.

    PubMed

    Schurgin, Mark W; Flombaum, Jonathan I

    2017-03-01

    Humans recognize thousands of objects, and with relative tolerance to variable retinal inputs. The acquisition of this ability is not fully understood, and it remains an area in which artificial systems have yet to surpass people. We sought to investigate the memory process that supports object recognition. Specifically, we investigated the association of inputs that co-occur over short periods of time. We tested the hypothesis that human perception exploits expectations about object kinematics to limit the scope of association to inputs that are likely to have the same token as a source. In several experiments we exposed participants to images of objects, and we then tested recognition sensitivity. Using motion, we manipulated whether successive encounters with an image took place through kinematics that implied the same or a different token as the source of those encounters. Images were injected with noise, or shown at varying orientations, and we included 2 manipulations of motion kinematics. Across all experiments, memory performance was better for images that had been previously encountered with kinematics that implied a single token. A model-based analysis similarly showed greater memory strength when images were shown via kinematics that implied a single token. These results suggest that constraints from physics are built into the mechanisms that support memory about objects. Such constraints-often characterized as 'Core Knowledge'-are known to support perception and cognition broadly, even in young infants. But they have never been considered as a mechanism for memory with respect to recognition. (PsycINFO Database Record

  17. Exploiting protein intrinsic flexibility in drug design.

    PubMed

    Lukman, Suryani; Verma, Chandra S; Fuentes, Gloria

    2014-01-01

    Molecular recognition in biological systems relies on the existence of specific attractive interactions between two partner molecules. Structure-based drug design seeks to identify and optimize such interactions between ligands and their protein targets. The approach followed in medicinal chemistry follows a combination of careful analysis of structural data together with experimental and/or theoretical studies on the system. This chapter focuses on the fact that a protein is not fully characterized by a single structure, but by an ensemble of states, some of them represent "hidden conformations" with cryptic binding sites. We highlight case studies where both experimental and computational methods have been used to mutually drive each other in an attempt to improve the success of the drug design approaches.Advances in both experimental techniques and computational methods have greatly improved our physico-chemical understanding of the functional mechanisms in biomolecules and opened a debate about the interplay between molecular structure and biomolecular function. The beautiful static pictures of protein structures may have led to neglecting the intrinsic protein flexibility, however we are entering a new era where more sophisticated methods are used to exploit this ability of macromolecules, and this will definitely lead to the inclusion of the notion in the pharmaceutical field of drug design.

  18. Relationship between exploitation, oscillation, MSY and extinction.

    PubMed

    Ghosh, Bapan; Kar, T K; Legovic, T

    2014-10-01

    We give answers to two important problems arising in current fisheries: (i) how maximum sustainable yield (MSY) policy is influenced by the initial population level, and (ii) how harvesting, oscillation and MSY are related to each other in prey-predator systems. To examine the impact of initial population on exploitation, we analyze a single species model with strong Allee effect. It is found that even when the MSY exists, the dynamic solution may not converge to the equilibrium stock if the initial population level is higher but near the critical threshold level. In a prey-predator system with Allee effect in the prey species, the initial population does not have such important impact neither on MSY nor on maximum sustainable total yield (MSTY). However, harvesting the top predator may cause extinction of all species if odd number of trophic levels exist in the ecosystem. With regard to the second problem, we study two prey-predator models and establish that increasing harvesting effort either on prey, predator or both prey and predator destroys previously existing oscillation. Moreover, equilibrium stock both at MSY and MSTY level is stable. We also discuss the validity of found results to other prey-predator systems.

  19. Accelerating Large Data Analysis By Exploiting Regularities

    NASA Technical Reports Server (NTRS)

    Moran, Patrick J.; Ellsworth, David

    2003-01-01

    We present techniques for discovering and exploiting regularity in large curvilinear data sets. The data can be based on a single mesh or a mesh composed of multiple submeshes (also known as zones). Multi-zone data are typical to Computational Fluid Dynamics (CFD) simulations. Regularities include axis-aligned rectilinear and cylindrical meshes as well as cases where one zone is equivalent to a rigid-body transformation of another. Our algorithms can also discover rigid-body motion of meshes in time-series data. Next, we describe a data model where we can utilize the results from the discovery process in order to accelerate large data visualizations. Where possible, we replace general curvilinear zones with rectilinear or cylindrical zones. In rigid-body motion cases we replace a time-series of meshes with a transformed mesh object where a reference mesh is dynamically transformed based on a given time value in order to satisfy geometry requests, on demand. The data model enables us to make these substitutions and dynamic transformations transparently with respect to the visualization algorithms. We present results with large data sets where we combine our mesh replacement and transformation techniques with out-of-core paging in order to achieve significant speed-ups in analysis.

  20. Exploiting spatial descriptions in visual scene analysis.

    PubMed

    Ziegler, Leon; Johannsen, Katrin; Swadzba, Agnes; De Ruiter, Jan P; Wachsmuth, Sven

    2012-08-01

    The reliable automatic visual recognition of indoor scenes with complex object constellations using only sensor data is a nontrivial problem. In order to improve the construction of an accurate semantic 3D model of an indoor scene, we exploit human-produced verbal descriptions of the relative location of pairs of objects. This requires the ability to deal with different spatial reference frames (RF) that humans use interchangeably. In German, both the intrinsic and relative RF are used frequently, which often leads to ambiguities in referential communication. We assume that there are certain regularities that help in specific contexts. In a first experiment, we investigated how speakers of German describe spatial relationships between different pieces of furniture. This gave us important information about the distribution of the RFs used for furniture-predicate combinations, and by implication also about the preferred spatial predicate. The results of this experiment are compiled into a computational model that extracts partial orderings of spatial arrangements between furniture items from verbal descriptions. In the implemented system, the visual scene is initially scanned by a 3D camera system. From the 3D point cloud, we extract point clusters that suggest the presence of certain furniture objects. We then integrate the partial orderings extracted from the verbal utterances incrementally and cumulatively with the estimated probabilities about the identity and location of objects in the scene, and also estimate the probable orientation of the objects. This allows the system to significantly improve both the accuracy and richness of its visual scene representation.

  1. Exploiting interspecific olfactory communication to monitor predators.

    PubMed

    Garvey, Patrick M; Glen, Alistair S; Clout, Mick N; Wyse, Sarah V; Nichols, Margaret; Pech, Roger P

    2017-03-01

    Olfaction is the primary sense of many mammals and subordinate predators use this sense to detect dominant species, thereby reducing the risk of an encounter and facilitating coexistence. Chemical signals can act as repellents or attractants and may therefore have applications for wildlife management. We devised a field experiment to investigate whether dominant predator (ferret Mustela furo) body odor would alter the behavior of three common mesopredators: stoats (Mustela erminea), hedgehogs (Erinaceus europaeus), and ship rats (Rattus rattus). We predicted that apex predator odor would lead to increased detections, and our results support this hypothesis as predator kairomones (interspecific olfactory messages that benefit the receiver) provoked "eavesdropping" behavior by mesopredators. Stoats exhibited the most pronounced responses, with kairomones significantly increasing the number of observations and the time spent at a site, so that their occupancy estimates changed from rare to widespread. Behavioral responses to predator odors can therefore be exploited for conservation and this avenue of research has not yet been extensively explored. A long-life lure derived from apex predator kairomones could have practical value, especially when there are plentiful resources that reduce the efficiency of food-based lures. Our results have application for pest management in New Zealand and the technique of using kairomones to monitor predators could have applications for conservation efforts worldwide.

  2. Haploids in flowering plants: origins and exploitation.

    PubMed

    Dunwell, Jim M

    2010-05-01

    The first haploid angiosperm, a dwarf form of cotton with half the normal chromosome complement, was discovered in 1920, and in the ninety years since then such plants have been identified in many other species. They can occur either spontaneously or can be induced by modified pollination methods in vivo, or by in vitro culture of immature male or female gametophytes. Haploids represent an immediate, one-stage route to homozygous diploids and thence to F(1) hybrid production. The commercial exploitation of heterosis in such F(1) hybrids leads to the development of hybrid seed companies and subsequently to the GM revolution in agriculture. This review describes the range of techniques available for the isolation or induction of haploids and discusses their value in a range of areas, from fundamental research on mutant isolation and transformation, through to applied aspects of quantitative genetics and plant breeding. It will also focus on how molecular methods have been used recently to explore some of the underlying aspects of this fascinating developmental phenomenon.

  3. Competing Discourses about Youth Sexual Exploitation in Canadian News Media

    PubMed Central

    Saewyc, Elizabeth M.; Miller, Bonnie B.; Rivers, Robert; Matthews, Jennifer; Hilario, Carla; Hirakata, Pam

    2015-01-01

    Media holds the power to create, maintain, or break down stigmatizing attitudes, which affect policies, funding, and services. To understand how Canadian news media depicts the commercial sexual exploitation of children and youth, we examined 835 Canadian newspaper articles from 1989–2008 using a mixed methods critical discourse analysis approach, comparing representations to existing research about sexually exploited youth. Despite research evidence that equal rates of boys and girls experience exploitation, Canadian news media depicted exploited youth predominantly as heterosexual girls, and described them alternately as victims or workers in a trade, often both in the same story. News media mentioned exploiters far less often than victims, and portrayed them almost exclusively as male, most often called ‘customers’ or ‘consumers,’ and occasionally ‘predators’; in contrast, research has documented the majority of sexually exploited boys report female exploiters. Few news stories over the past two decades portrayed the diversity of victims, perpetrators, and venues of exploitation reported in research. The focus on victims but not exploiters helps perpetuate stereotypes of sexual exploitation as business or a ‘victimless crime,’ maintains the status quo, and blurs responsibility for protecting youth under the UN Convention on the Rights of the Child. Health care providers and researchers can be advocates for accuracy in media coverage about sexual exploitation; news reporters and editors should focus on exploiters more than victims, draw on existing research evidence to avoid perpetuating stereotypes, and use accurate terms, such as commercial sexual exploitation, rather than terms related to business or trade. PMID:26793015

  4. Exploiting Copper Redox for (19)F Magnetic Resonance-Based Detection of Cellular Hypoxia.

    PubMed

    Xie, Da; King, Tyler L; Banerjee, Arnab; Kohli, Vikraant; Que, Emily L

    2016-03-09

    We report a pair of fluorinated, redox-active copper complexes for potential use as (19)F MRI contrast agents for detecting cellular hypoxia. Trifluorinated Cu(II) ATSM-F3 displays the appropriate redox potential for selective accumulation in hypoxic cells and a completely quenched (19)F NMR signal that is "turned on" following reduction to Cu(I). Incubation of cancer cells with CuATSM-F3 resulted in a selective detection of (19)F signal in cells grown under hypoxic conditions.

  5. Exploiting Magnetic Resonance Angiography Imaging Improves Model Estimation of BOLD Signal

    PubMed Central

    Hu, Zhenghui; Liu, Cong; Shi, Pengcheng; Liu, Huafeng

    2012-01-01

    The change of BOLD signal relies heavily upon the resting blood volume fraction () associated with regional vasculature. However, existing hemodynamic data assimilation studies pretermit such concern. They simply assign the value in a physiologically plausible range to get over ill-conditioning of the assimilation problem and fail to explore actual . Such performance might lead to unreliable model estimation. In this work, we present the first exploration of the influence of on fMRI data assimilation, where actual within a given cortical area was calibrated by an MR angiography experiment and then was augmented into the assimilation scheme. We have investigated the impact of on single-region data assimilation and multi-region data assimilation (dynamic cause modeling, DCM) in a classical flashing checkerboard experiment. Results show that the employment of an assumed in fMRI data assimilation is only suitable for fMRI signal reconstruction and activation detection grounded on this signal, and not suitable for estimation of unobserved states and effective connectivity study. We thereby argue that introducing physically realistic in the assimilation process may provide more reliable estimation of physiological information, which contributes to a better understanding of the underlying hemodynamic processes. Such an effort is valuable and should be well appreciated. PMID:22384043

  6. Against Permitted Exploitation in Developing World Research Agreements.

    PubMed

    Wenner, Danielle M

    2016-04-01

    This paper examines the moral force of exploitation in developing world research agreements. Taking for granted that some clinical research which is conducted in the developing world but funded by developed world sponsors is exploitative, it asks whether a third party would be morally justified in enforcing limits on research agreements in order to ensure more fair and less exploitative outcomes. This question is particularly relevant when such exploitative transactions are entered into voluntarily by all relevant parties, and both research sponsors and host communities benefit from the resulting agreements. I show that defenders of the claim that exploitation ought to be permitted rely on a mischaracterization of certain forms of interference as unjustly paternalistic and two dubious empirical assumptions about the results of regulation. The view I put forward is that by evaluating a system of constraints on international research agreements, rather than individual transaction-level interference, we can better assess the alternatives to permitting exploitative research agreements.

  7. Transnational gestational surrogacy: does it have to be exploitative?

    PubMed

    Kirby, Jeffrey

    2014-01-01

    This article explores the controversial practice of transnational gestational surrogacy and poses a provocative question: Does it have to be exploitative? Various existing models of exploitation are considered and a novel exploitation-evaluation heuristic is introduced to assist in the analysis of the potentially exploitative dimensions/elements of complex health-related practices. On the basis of application of the heuristic, I conclude that transnational gestational surrogacy, as currently practiced in low-income country settings (such as rural, western India), is exploitative of surrogate women. Arising out of consideration of the heuristic's exploitation conditions, a set of public education and enabled choice, enhanced protections, and empowerment reforms to transnational gestational surrogacy practice is proposed that, if incorporated into a national regulatory framework and actualized within a low income country, could possibly render such practice nonexploitative.

  8. Exploiting Untapped Information Resources in Earth Science

    NASA Astrophysics Data System (ADS)

    Ramachandran, R.; Fox, P. A.; Kempler, S.; Maskey, M.

    2015-12-01

    One of the continuing challenges in any Earth science investigation is the amount of time and effort required for data preparation before analysis can begin. Current Earth science data and information systems have their own shortcomings. For example, the current data search systems are designed with the assumption that researchers find data primarily by metadata searches on instrument or geophysical keywords, assuming that users have sufficient knowledge of the domain vocabulary to be able to effectively utilize the search catalogs. These systems lack support for new or interdisciplinary researchers who may be unfamiliar with the domain vocabulary or the breadth of relevant data available. There is clearly a need to innovate and evolve current data and information systems in order to improve data discovery and exploration capabilities to substantially reduce the data preparation time and effort. We assert that Earth science metadata assets are dark resources, information resources that organizations collect, process, and store for regular business or operational activities but fail to utilize for other purposes. The challenge for any organization is to recognize, identify and effectively utilize the dark data stores in their institutional repositories to better serve their stakeholders. NASA Earth science metadata catalogs contain dark resources consisting of structured information, free form descriptions of data and pre-generated images. With the addition of emerging semantic technologies, such catalogs can be fully utilized beyond their original design intent of supporting current search functionality. In this presentation, we will describe our approach of exploiting these information resources to provide novel data discovery and exploration pathways to science and education communities

  9. Exploitation of Parallelism in Climate Models

    SciTech Connect

    Baer, F.; Tribbia, J.J.; Williamson, D.L.

    1999-03-01

    The US Department of Energy (DOE), through its CHAMMP initiative, hopes to develop the capability to make meaningful regional climate forecasts on time scales exceeding a decade, such capability to be based on numerical prediction type models. We propose research to contribute to each of the specific items enumerated in the CHAMMP announcement (Notice 91-3); i.e., to consider theoretical limits to prediction of climate and climate change on appropriate time scales, to develop new mathematical techniques to utilize massively parallel processors (MPP), to actually utilize MPPs as a research tool, and to develop improved representations of some processes essential to climate prediction. In particular, our goals are to: (1) Reconfigure the prediction equations such that the time iteration process can be compressed by use of MMP architecture, and to develop appropriate algorithms. (2) Develop local subgrid scale models which can provide time and space dependent parameterization for a state- of-the-art climate model to minimize the scale resolution necessary for a climate model, and to utilize MPP capability to simultaneously integrate those subgrid models and their statistics. (3) Capitalize on the MPP architecture to study the inherent ensemble nature of the climate problem. By careful choice of initial states, many realizations of the climate system can be determined concurrently and more realistic assessments of the climate prediction can be made in a realistic time frame. To explore these initiatives, we will exploit all available computing technology, and in particular MPP machines. We anticipate that significant improvements in modeling of climate on the decadal and longer time scales for regional space scales will result from our efforts.

  10. Experiments with Helmholtz Resonators.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1996-01-01

    Presents experiments that use Helmholtz resonators and have been designed for a sophomore-level course in oscillations and waves. Discusses the theory of the Helmholtz resonator and resonance curves. (JRH)

  11. MRI (Magnetic Resonance Imaging)

    MedlinePlus

    ... and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... usually given through an IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) ...

  12. Regenerative feedback resonant circuit

    DOEpatents

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  13. Beyond Fair Benefits: Reconsidering Exploitation Arguments Against Organ Markets.

    PubMed

    Koplin, Julian J

    2017-02-04

    One common objection to establishing regulated live donor organ markets is that such markets would be exploitative. Perhaps surprisingly, exploitation arguments against organ markets have been widely rejected in the philosophical literature on the subject. It is often argued that concerns about exploitation should be addressed by increasing the price paid to organ sellers, not by banning the trade outright. I argue that this analysis rests on a particular conception of exploitation (which I refer to as 'fair benefits' exploitation), and outline two additional ways that the charge of exploitation can be understood (which I discuss in terms of 'fair process' exploitation and complicity in injustice). I argue that while increasing payments to organ sellers may mitigate or eliminate fair benefits exploitation, such measures will not necessarily address fair process exploitation or complicity in injustice. I further argue that each of these three forms of wrongdoing is relevant to the ethics of paid living organ donation, as well as the design of public policy more generally.

  14. Simulation of subsea gas hydrate exploitation

    NASA Astrophysics Data System (ADS)

    Janicki, Georg; Schlüter, Stefan; Hennig, Torsten; Deerberg, Görge

    2014-05-01

    The recovery of methane from gas hydrate layers that have been detected in several subsea sediments and permafrost regions around the world is a promising perspective to overcome future shortages in natural gas supply. Being aware that conventional natural gas resources are limited, research is going on to develop technologies for the production of natural gas from such new sources. Thus various research programs have started since the early 1990s in Japan, USA, Canada, India, and Germany to investigate hydrate deposits and develop required technologies. In recent years, intensive research has focussed on the capture and storage of CO2 from combustion processes to reduce climate impact. While different natural or man-made reservoirs like deep aquifers, exhausted oil and gas deposits or other geological formations are considered to store gaseous or liquid CO2, the storage of CO2 as hydrate in former methane hydrate fields is another promising alternative. Due to beneficial stability conditions, methane recovery may be well combined with CO2 storage in the form of hydrates. Regarding technological implementation many problems have to be overcome. Especially mixing, heat and mass transfer in the reservoir are limiting factors causing very long process times. Within the scope of the German research project »SUGAR« different technological approaches for the optimized exploitation of gas hydrate deposits are evaluated and compared by means of dynamic system simulations and analysis. Detailed mathematical models for the most relevant chemical and physical processes are developed. The basic mechanisms of gas hydrate formation/dissociation and heat and mass transport in porous media are considered and implemented into simulation programs. Simulations based on geological field data have been carried out. The studies focus on the potential of gas production from turbidites and their fitness for CO2 storage. The effects occurring during gas production and CO2 storage within

  15. Simulated population responses of common carp to commercial exploitation

    SciTech Connect

    Weber, Michael J.; Hennen, Matthew J.; Brown, Michael L.

    2011-12-01

    Common carp Cyprinus carpio is a widespread invasive species that can become highly abundant and impose deleterious ecosystem effects. Thus, aquatic resource managers are interested in controlling common carp populations. Control of invasive common carp populations is difficult, due in part to the inherent uncertainty of how populations respond to exploitation. To understand how common carp populations respond to exploitation, we evaluated common carp population dynamics (recruitment, growth, and mortality) in three natural lakes in eastern South Dakota. Common carp exhibited similar population dynamics across these three systems that were characterized by consistent recruitment (ages 3 to 15 years present), fast growth (K = 0.37 to 0.59), and low mortality (A = 1 to 7%). We then modeled the effects of commercial exploitation on size structure, abundance, and egg production to determine its utility as a management tool to control populations. All three populations responded similarly to exploitation simulations with a 575-mm length restriction, representing commercial gear selectivity. Simulated common carp size structure modestly declined (9 to 37%) in all simulations. Abundance of common carp declined dramatically (28 to 56%) at low levels of exploitation (0 to 20%) but exploitation >40% had little additive effect and populations were only reduced by 49 to 79% despite high exploitation (>90%). Maximum lifetime egg production was reduced from 77 to 89% at a moderate level of exploitation (40%), indicating the potential for recruitment overfishing. Exploitation further reduced common carp size structure, abundance, and egg production when simulations were not size selective. Our results provide insights to how common carp populations may respond to exploitation. Although commercial exploitation may be able to partially control populations, an integrated removal approach that removes all sizes of common carp has a greater chance of controlling population abundance

  16. Exploiting for medical and biological applications

    NASA Astrophysics Data System (ADS)

    Giano, Michael C.

    Biotherapeutics are an emerging class of drug composed of molecules ranging in sizes from peptides to large proteins. Due to their poor stability and mucosal membrane permeability, biotherapeutics are administered by a parenteral method (i.e., syringe, intravenous or intramuscular). Therapeutics delivered systemically often experience short half-lives. While, local administration may involve invasive surgical procedures and suffer from poor retention at the site of application. To compensate, the patient receives frequent doses of highly concentrated therapeutic. Unfortunately, the off-target side effects and discomfort associated with multiple injections results in poor patient compliance. Therefore, new delivery methods which can improve therapeutic retention, reduce the frequency of administration and may aid in decreasing the off-target side effects is a necessity. Hydrogels are a class of biomaterials that are gaining interests for tissue engineering and drug delivery applications. Hydrogel materials are defined as porous, 3-dimensional networks that are primarily composed of water. Generally, they are mechanically rigid, cytocompatible and easily chemically functionalized. Collectively, these properties make hydrogels fantastic candidates to perform as drug delivery depots. Current hydrogel delivery systems physically entrap the target therapeutic which is then subsequently released over time at the site of administration. The swelling and degradation of the material effect the diffusion of the therapy from the hydrogel, and therefore should be controlled. Although these strategies provide some regulation over therapeutic release, full control of the delivery is not achieved. Newer approaches are focused on designing hydrogels that exploit known interactions, covalently attach the therapy or respond to an external stimulus in an effort to gain improved control over the therapy's release. Unfortunately, the biotherapeutic is typically required to be chemically

  17. Resonance beyond frequency-matching: multidimensional resonance

    NASA Astrophysics Data System (ADS)

    Wang, Zhenyu; Li, Mingzhe; Wang, Ruifang

    2017-03-01

    Resonance, conventionally defined as the oscillation of a system when the temporal frequency of an external stimulus matches a natural frequency of the system, is important in both fundamental physics and applied disciplines. However, the spatial character of oscillation is not considered in this definition. We reveal the creation of spatial resonance when the stimulus matches the space pattern of a normal mode in an oscillating system. The complete resonance, which we call multidimensional resonance, should be a combination of both the temporal and the spatial resonance. We further elucidate that the spin wave produced by multidimensional resonance drives considerably faster reversal of the vortex core in a magnetic nanodisc. Multidimensional resonance provides insight into the nature of wave dynamics and opens the door to novel applications.

  18. Reservoir engineering of a mechanical resonator: generating a macroscopic superposition state and monitoring its decoherence

    NASA Astrophysics Data System (ADS)

    Asjad, Muhammad; Vitali, David

    2014-02-01

    A deterministic scheme for generating a macroscopic superposition state of a nanomechanical resonator is proposed. The nonclassical state is generated through a suitably engineered dissipative dynamics exploiting the optomechanical quadratic interaction with a bichromatically driven optical cavity mode. The resulting driven dissipative dynamics can be employed for monitoring and testing the decoherence processes affecting the nanomechanical resonator under controlled conditions.

  19. A Descriptive Study on Sexually Exploited Children in Residential Treatment

    ERIC Educational Resources Information Center

    Twill, Sarah E.; Green, Denise M.; Traylor, Amy

    2010-01-01

    Sexual exploitation and prostitution of children and adolescents is a multibillion dollar industry in the United States (Estes and Weiner in "Medical, legal & social science aspects of child sexual exploitation: A comprehensive review of pornography, prostitution, and internet crimes, vol I," G.W. Medical Publishing, Inc, St Louis,…

  20. Exploiting the Immunological Effects of Standard Treatments in Prostate Cancer

    DTIC Science & Technology

    2009-03-01

    Exploiting the Immunological Effects of Standard Treatments in Prostate Cancer PRINCIPAL INVESTIGATOR: Brad H. Nelson, Ph.D...From - To) 1 MAR 2008 - 28 FEB 2009 4. TITLE AND SUBTITLE Exploiting the immunological effects of standard treatments in 5a. CONTRACT NUMBER...treatment of prostate cancer. 15. SUBJECT TERMS Tumor immunology , immunotherapy, prostate cancer, antibody, T cell, tumor antigen, hormone therapy

  1. Self-Report Measure of Financial Exploitation of Older Adults

    ERIC Educational Resources Information Center

    Conrad, Kendon J.; Iris, Madelyn; Ridings, John W.; Langley, Kate; Wilber, Kathleen H.

    2010-01-01

    Purpose: This study was designed to improve the measurement of financial exploitation (FE) by testing psychometric properties of the older adult financial exploitation measure (OAFEM), a client self-report instrument. Design and Methods: Rasch item response theory and traditional validation approaches were used. Questionnaires were administered by…

  2. Detection of internal fields in double-metal terahertz resonators

    NASA Astrophysics Data System (ADS)

    Mitrofanov, Oleg; Han, Zhanghua; Ding, Fei; Bozhevolnyi, Sergey I.; Brener, Igal; Reno, John L.

    2017-02-01

    Terahertz (THz) double-metal plasmonic resonators enable enhanced light-matter coupling by exploiting strong field confinement. The double-metal design however restricts access to the internal fields. We propose and demonstrate a method for spatial mapping and spectroscopic analysis of the internal electromagnetic fields in double-metal plasmonic resonators. We use the concept of image charges and aperture-type scanning near-field THz time-domain microscopy to probe the fields confined within the closed resonator. The experimental method opens doors to studies of light-matter coupling in deeply sub-wavelength volumes at THz frequencies.

  3. [Ecotourism exploitation model in Bita Lake Natural Reserve of Yunnan].

    PubMed

    Yang, G; Wang, Y; Zhong, L

    2000-12-01

    Bita lake provincial natural reserve is located in Shangri-La region of North-western Yunnan, and was set as a demonstrating area for ecotourism exploitation in 1998. After a year's exploitation construction and half a year's operation as a branch of the 99' Kunming International Horticulture Exposition to accept tourists, it was proved that the ecotourism demonstrating area attained four integrated functions of ecotourism, i.e., tourism, protection, poverty clearing and environment education. Five exploitation and management models including function zoned exploitation model, featured tourism communication model signs system designing model, local Tibetan family reception model and environmental monitoring model, were also successful, which were demonstrated and spreaded to the whole province. Bita lake provincial natural reserve could be a good sample for the ecotourism exploitation natural reserves of the whole country.

  4. The Intersection of Financial Exploitation and Financial Capacity

    PubMed Central

    Lichtenberg, P.A.

    2016-01-01

    Research in the past decade has documented that financial exploitation of older adults has become a major problem and Psychology is only recently increasing its presence in efforts to reduce exploitation. During the same time period, Psychology has been a leader in setting best practices for the assessment of diminished capacity in older adults culminating in the 2008 ABA/APA joint publication on a handbook for psychologists. Assessment of financial decision making capacity is often the cornerstone assessment needed in cases of financial exploitation. This paper will examine the intersection of financial exploitation and decision making capacity; introduce a new conceptual model and new tools for both the investigation and prevention of financial exploitation. PMID:27159438

  5. Exploit and ignore the consequences: A mother of planetary issues

    NASA Astrophysics Data System (ADS)

    Moustafa, K.

    2016-07-01

    Many environmental and planetary issues are due to an exploitation strategy based on exploit, consume and ignore the consequences. As many natural and environmental resources are limited in time and space, such exploitation approach causes important damages on earth, in the sea and maybe soon in the space. To sustain conditions under which humans and other living species can coexist in productive and dynamic harmony with their environments, terrestrial and space exploration programs may need to be based on 'scrutinize the consequences, prepare adequate solutions and then, only then, exploit'. Otherwise, the exploitation of planetary resources may put the environmental stability and sustainability at a higher risk than it is currently predicted. (C) 2016 Elsevier B.V. All rights reserved.

  6. Mode Coupling and Nonlinear Resonances of MEMS Arch Resonators for Bandpass Filters

    NASA Astrophysics Data System (ADS)

    Hajjaj, Amal Z.; Hafiz, Md Abdullah; Younis, Mohammad I.

    2017-01-01

    We experimentally demonstrate an exploitation of the nonlinear softening, hardening, and veering phenomena (near crossing), where the frequencies of two vibration modes get close to each other, to realize a bandpass filter of sharp roll off from the passband to the stopband. The concept is demonstrated based on an electrothermally tuned and electrostatically driven MEMS arch resonator operated in air. The in-plane resonator is fabricated from a silicon-on-insulator wafer with a deliberate curvature to form an arch shape. A DC current is applied through the resonator to induce heat and modulate its stiffness, and hence its resonance frequencies. We show that the first resonance frequency increases up to twice of the initial value while the third resonance frequency decreases until getting very close to the first resonance frequency. This leads to the phenomenon of veering, where both modes get coupled and exchange energy. We demonstrate that by driving both modes nonlinearly and electrostatically near the veering regime, such that the first and third modes exhibit softening and hardening behavior, respectively, sharp roll off from the passband to the stopband is achievable. We show a flat, wide, and tunable bandwidth and center frequency by controlling the electrothermal actuation voltage.

  7. Mode Coupling and Nonlinear Resonances of MEMS Arch Resonators for Bandpass Filters

    PubMed Central

    Hajjaj, Amal Z.; Hafiz, Md Abdullah; Younis, Mohammad I.

    2017-01-01

    We experimentally demonstrate an exploitation of the nonlinear softening, hardening, and veering phenomena (near crossing), where the frequencies of two vibration modes get close to each other, to realize a bandpass filter of sharp roll off from the passband to the stopband. The concept is demonstrated based on an electrothermally tuned and electrostatically driven MEMS arch resonator operated in air. The in-plane resonator is fabricated from a silicon-on-insulator wafer with a deliberate curvature to form an arch shape. A DC current is applied through the resonator to induce heat and modulate its stiffness, and hence its resonance frequencies. We show that the first resonance frequency increases up to twice of the initial value while the third resonance frequency decreases until getting very close to the first resonance frequency. This leads to the phenomenon of veering, where both modes get coupled and exchange energy. We demonstrate that by driving both modes nonlinearly and electrostatically near the veering regime, such that the first and third modes exhibit softening and hardening behavior, respectively, sharp roll off from the passband to the stopband is achievable. We show a flat, wide, and tunable bandwidth and center frequency by controlling the electrothermal actuation voltage. PMID:28134329

  8. Noise in nonlinear nanoelectromechanical resonators

    NASA Astrophysics Data System (ADS)

    Guerra Vidal, Diego N.

    Nano-Electro-Mechanical Systems (NEMS), due to their nanometer scale size, possess a number of desirable attributes: high sensitivity to applied forces, fast response times, high resonance frequencies and low power consumption. However, ultra small size and low power handling result in unwanted consequences: smaller signal size and higher dissipation, making the NEMS devices more susceptible to external and intrinsic noise. The simplest version of a NEMS, a suspended nanomechanical structure with two distinct excitation states, can be used as an archetypal two state system to study a plethora of fundamental phenomena such as Duffing nonlinearity, stochastic resonance, and macroscopic quantum tunneling at low temperatures. From a technical perspective, there are numerous applications such nanomechanical memory elements, microwave switches and nanomechanical computation. The control and manipulation of the mechanical response of these two state systems can be realized by exploiting a (seemingly) counterintuitive physical phenomenon, Stochastic Resonance: in a noisy nonlinear mechanical system, the presence of noise can enhance the system response to an external stimulus. This Thesis is mainly dedicated to study possible applications of Stochastic Resonance in two-state nanomechanical systems. First, on chip signal amplification by 1/falpha is observed. The effectiveness of the noise assisted amplification is observed to decrease with increasing a. Experimental evidence shows an increase in asymmetry between the two states with increasing noise color. Considering the prevalence of 1/f alpha noise in the materials in integrated circuits, the signal enhancement demonstrated here, suggests beneficial use of the otherwise detrimental noise. Finally, a nanomechanical device, operating as a reprogrammable logic gate, and performing fundamental logic functions such as AND/OR and NAND/NOR is presented. The logic function can be programmed (from AND to OR) dynamically, by

  9. Electromagnetic Transmission Through Resonant Structures

    NASA Astrophysics Data System (ADS)

    Young, Steven M.

    Electromagnetic resonators store energy in the form of oscillatory electric and magnetic fields and gradually exchange that energy by coupling with their environment. This coupling process can have profound effects on the transmission and reflection properties of nearby interfaces, with rapid transitions from high transmittance to high reflectance over narrow frequency ranges, and has been exploited to design useful optical components such as spectral filters and dielectric mirrors. This dissertation includes analytic, numeric, and experimental investigations of three different electromagnetic resonators, each based on a different method of confining electromagnetic fields near the region of interest. First, we show that a structure with two parallel conducting plates, each containing a subwavelength slit, supports a localized resonant mode bound to the slits and therefore exhibits (in the absence of nonradiative losses), perfect resonant transmission over a narrow frequency range. In practice, the transmission is limited by conduction losses in the sidewalls; nevertheless, experimental results at 10 GHz show a narrowband transmission enhancement by a factor of 104 compared to the non-resonant transmission, with quality factor (ratio of frequency to peak width) Q ~ 3000. Second, we describe a narrowband transmission filter based on a single-layer dielectric grating. We use a group theory analysis to show that, due to their symmetry, several of the grating modes cannot couple to light at normal incidence, while several others have extremely large coupling. We then show how selectively breaking the system symmetry using off-normal light incidence can produce transmission peaks by enabling weak coupling to some of the previously protected modes. The narrowband filtering capabilities are validated by an experimental demonstration in the long wavelength infrared, showing transmission peaks of quality factor Q ~ 100 within a free-spectral range of 8-15 mum. Third, we

  10. Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging.

    PubMed

    Webb, Andrew

    2014-11-01

    Cavity resonators are widely used in electron paramagnetic resonance, very high field magnetic resonance microimaging and also in high field human imaging. The basic principles and designs of different forms of cavity resonators including rectangular, cylindrical, re-entrant, cavity magnetrons, toroidal cavities and dielectric resonators are reviewed. Applications in EPR and MRI are summarized, and finally the topic of traveling wave MRI using the magnet bore as a waveguide is discussed.

  11. Experimental realization of extraordinary acoustic transmission using Helmholtz resonators

    NASA Astrophysics Data System (ADS)

    Crow, Brian C.; Cullen, Jordan M.; McKenzie, William W.; Koju, Vijay; Robertson, William M.

    2015-02-01

    The phenomenon of extraordinary acoustic transmission through a solid barrier with an embedded Helmholtz resonator (HR) is demonstrated. The Helmholtz resonator consists of an embedded cavity and two necks that protrude, one on each side of the barrier. Extraordinary transmission occurs for a narrow spectral range encompassing the resonant frequency of the Helmholtz resonator. We show that an amplitude transmission of 97.5% is achieved through a resonator whose neck creates an open area of 6.25% of the total barrier area. In addition to the enhanced transmission, we show that there is a smooth, continuous phase transition in the transmitted sound as a function of frequency. The frequency dependent phase transition is used to experimentally realize slow wave propagation for a narrow-band Gaussian wave packet centered at the maximum transmission frequency. The use of parallel pairs of Helmholtz resonators tuned to different resonant frequencies is experimentally explored as a means of increasing the transmission bandwidth. These experiments show that because of the phase transition, there is always a frequency between the two Helmholtz resonant frequencies at which destructive interference occurs whether the resonances are close or far apart. Finally, we explain how the phase transition associated with Helmholtz-resonator-mediated extraordinary acoustic transmission can be exploited to produce diffractive acoustic components including sub-wavelength thickness acoustic lenses.

  12. Experimental realization of extraordinary acoustic transmission using Helmholtz resonators

    SciTech Connect

    Crow, Brian C.; Cullen, Jordan M.; McKenzie, William W.; Koju, Vijay; Robertson, William M.

    2015-02-15

    The phenomenon of extraordinary acoustic transmission through a solid barrier with an embedded Helmholtz resonator (HR) is demonstrated. The Helmholtz resonator consists of an embedded cavity and two necks that protrude, one on each side of the barrier. Extraordinary transmission occurs for a narrow spectral range encompassing the resonant frequency of the Helmholtz resonator. We show that an amplitude transmission of 97.5% is achieved through a resonator whose neck creates an open area of 6.25% of the total barrier area. In addition to the enhanced transmission, we show that there is a smooth, continuous phase transition in the transmitted sound as a function of frequency. The frequency dependent phase transition is used to experimentally realize slow wave propagation for a narrow-band Gaussian wave packet centered at the maximum transmission frequency. The use of parallel pairs of Helmholtz resonators tuned to different resonant frequencies is experimentally explored as a means of increasing the transmission bandwidth. These experiments show that because of the phase transition, there is always a frequency between the two Helmholtz resonant frequencies at which destructive interference occurs whether the resonances are close or far apart. Finally, we explain how the phase transition associated with Helmholtz-resonator-mediated extraordinary acoustic transmission can be exploited to produce diffractive acoustic components including sub-wavelength thickness acoustic lenses.

  13. Uncertainty of exploitation estimates made from tag returns

    USGS Publications Warehouse

    Miranda, L.E.; Brock, R.E.; Dorr, B.S.

    2002-01-01

    Over 6,000 crappies Pomoxis spp. were tagged in five water bodies to estimate exploitation rates by anglers. Exploitation rates were computed as the percentage of tags returned after adjustment for three sources of uncertainty: postrelease mortality due to the tagging process, tag loss, and the reporting rate of tagged fish. Confidence intervals around exploitation rates were estimated by resampling from the probability distributions of tagging mortality, tag loss, and reporting rate. Estimates of exploitation rates ranged from 17% to 54% among the five study systems. Uncertainty around estimates of tagging mortality, tag loss, and reporting resulted in 90% confidence intervals around the median exploitation rate as narrow as 15 percentage points and as broad as 46 percentage points. The greatest source of estimation error was uncertainty about tag reporting. Because the large investments required by tagging and reward operations produce imprecise estimates of the exploitation rate, it may be worth considering other approaches to estimating it or simply circumventing the exploitation question altogether.

  14. Rationalising predictors of child sexual exploitation and sex-trading.

    PubMed

    Klatt, Thimna; Cavner, Della; Egan, Vincent

    2014-02-01

    Although there is evidence for specific risk factors leading to child sexual exploitation and prostitution, these influences overlap and have rarely been examined concurrently. The present study examined case files for 175 young persons who attended a voluntary organization in Leicester, United Kingdom, which supports people who are sexually exploited or at risk of sexual exploitation. Based on the case files, the presence or absence of known risk factors for becoming a sex worker was coded. Data were analyzed using t-test, logistic regression, and smallest space analysis. Users of the voluntary organization's services who had been sexually exploited exhibited a significantly greater number of risk factors than service users who had not been victims of sexual exploitation. The logistic regression produced a significant model fit. However, of the 14 potential predictors--many of which were associated with each other--only four variables significantly predicted actual sexual exploitation: running away, poverty, drug and/or alcohol use, and having friends or family members in prostitution. Surprisingly, running away was found to significantly decrease the odds of becoming involved in sexual exploitation. Smallest space analysis of the data revealed 5 clusters of risk factors. Two of the clusters, which reflected a desperation and need construct and immature or out-of-control lifestyles, were significantly associated with sexual exploitation. Our research suggests that some risk factors (e.g. physical and emotional abuse, early delinquency, and homelessness) for becoming involved in sexual exploitation are common but are part of the problematic milieu of the individuals affected and not directly associated with sex trading itself. Our results also indicate that it is important to engage with the families and associates of young persons at risk of becoming (or remaining) a sex worker if one wants to reduce the numbers of persons who engage in this activity.

  15. Droplet resonator based optofluidic microlasers

    NASA Astrophysics Data System (ADS)

    Kiraz, Alper; Jonáš, Alexandr; Aas, Mehdi; Karadag, Yasin; Brzobohatý, Oto; Ježek, Jan; Pilát, Zdeněk.; Zemánek, Pavel; Anand, Suman; McGloin, David

    2014-03-01

    We introduce tunable optofluidic microlasers based on active optical resonant cavities formed by optically stretched, dye-doped emulsion droplets confined in a dual-beam optical trap. To achieve tunable dye lasing, optically pumped droplets of oil dispersed in water are stretched by light in the dual-beam trap. Subsequently, resonant path lengths of whispering gallery modes (WGMs) propagating in the droplet are modified, leading to shifts in the microlaser emission wavelengths. We also report lasing in airborne, Rhodamine B-doped glycerolwater droplets which were localized using optical tweezers. While being trapped near the focal point of an infrared laser, the droplets were pumped with a Q-switched green laser. Furthermore, biological lasing in droplets supported by a superhydrophobic surface is demonstrated using a solution of Venus variant of the yellow fluorescent protein or E. Coli bacterial cells expressing stably the Venus protein. Our results may lead to new ways of probing airborne particles, exploiting the high sensitivity of stimulated emission to small perturbations in the droplet laser cavity and the gain medium.

  16. Integral resonator gyroscope

    NASA Technical Reports Server (NTRS)

    Shcheglov, Kirill V. (Inventor); Challoner, A. Dorian (Inventor); Hayworth, Ken J. (Inventor); Wiberg, Dean V. (Inventor); Yee, Karl Y. (Inventor)

    2008-01-01

    The present invention discloses an inertial sensor having an integral resonator. A typical sensor comprises a planar mechanical resonator for sensing motion of the inertial sensor and a case for housing the resonator. The resonator and a wall of the case are defined through an etching process. A typical method of producing the resonator includes etching a baseplate, bonding a wafer to the etched baseplate, through etching the wafer to form a planar mechanical resonator and the wall of the case and bonding an end cap wafer to the wall to complete the case.

  17. Simulation Concept - How to Exploit Tools for Computing Hybrids

    DTIC Science & Technology

    2009-07-01

    multiphysics design tools (Simulation of Biological Systems - SIMBIOSYS ), provide an open source environment for biological simulation tools (Bio...SCHETCH Simulation Concept – How to Exploit Tools for Computing Project SIMBIOSYS Simulation of Biological Systems Program SPICE Simulation

  18. Theoretical investigation of phonon polaritons in SiC micropillar resonators

    NASA Astrophysics Data System (ADS)

    Gubbin, Christopher R.; Maier, Stefan A.; De Liberato, Simone

    2017-01-01

    Of late there has been a surge of interest in localized phonon polariton resonators which allow for the subdiffraction confinement of light in the midinfrared spectral region by coupling to optical phonons at the surface of polar dielectrics. Resonators are generally etched on deep substrates which support propagative surface phonon polariton resonances. Recent experimental work has shown that understanding the coupling between localized and propagative surface phonon polaritons in these systems is vital to correctly describing the system resonances. In this paper we comprehensively investigate resonators composed of arrays of cylindrical SiC resonators on SiC substrates. Our bottom-up approach, starting from the resonances of single, free-standing cylinders and isolated substrates, and exploiting both numerical and analytical techniques, allows us to develop a consistent understanding of the parameter space of those resonators, putting on firmer ground this blossoming technology.

  19. Exploiting Elementary Landscapes for TSP, Vehicle Routing and Scheduling

    DTIC Science & Technology

    2015-09-03

    AFRL-AFOSR-VA-TR-2015-0320 EXPLOITING ELEMENTARY LANDSCAPES FOR TSP, VEHICLE ROUTING AND SCHEDULING Darrell Whitley COLORADO STATE UNIVERSITY Final...4. TITLE AND SUBTITLE Exploiting Elementary Landscapes for TSP, Vehicle Routing and Scheduling 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-11-1-0088...There are a number of NP-hard optimization problems where the search space can be characterized as an elementary landscape. For these search spaces the

  20. Preventing Exploits Against Software of Uncertain Provenance (PEASOUP)

    DTIC Science & Technology

    2015-05-01

    results of the research and development of PEASOUP (Preventing Exploits Against Software of Uncertain Provenance), a technology that enables the safe...Preventing Exploits Against Software of Uncertain Provenance), a technology that enables the safe execution of software executables. PEASOUP...Products and Transferable Technology 5 2.2 Use of Third-Party COTS Products 7 2.3 Overview of the Technical Approach and Plan 8 2.4 2.4.1 The (Offline

  1. Technical Risk Analysis - Exploiting the Power of MBSE

    DTIC Science & Technology

    2012-11-01

    UNCLASSIFIED DSTO-GD-0734 18. Technical Risk Analysis – Exploiting the Power of MBSE – Despina Tramoundanis1, Wayne Power1 and Daniel Spencer2...Functional Risk Analysis (FRA) conducted within a Model Based Systems Engineering ( MBSE ) environment. FRA is a rigorous technique used to explore potential...TITLE AND SUBTITLE Technical Risk Analysis â Exploiting the Power of MBSE â 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  2. Partially orthogonal resonators for magnetic resonance imaging

    PubMed Central

    Chacon-Caldera, Jorge; Malzacher, Matthias; Schad, Lothar R.

    2017-01-01

    Resonators for signal reception in magnetic resonance are traditionally planar to restrict coil material and avoid coil losses. Here, we present a novel concept to model resonators partially in a plane with maximum sensitivity to the magnetic resonance signal and partially in an orthogonal plane with reduced signal sensitivity. Thus, properties of individual elements in coil arrays can be modified to optimize physical planar space and increase the sensitivity of the overall array. A particular case of the concept is implemented to decrease H-field destructive interferences in planar concentric in-phase arrays. An increase in signal to noise ratio of approximately 20% was achieved with two resonators placed over approximately the same planar area compared to common approaches at a target depth of 10 cm at 3 Tesla. Improved parallel imaging performance of this configuration is also demonstrated. The concept can be further used to increase coil density. PMID:28186135

  3. Partially orthogonal resonators for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Chacon-Caldera, Jorge; Malzacher, Matthias; Schad, Lothar R.

    2017-02-01

    Resonators for signal reception in magnetic resonance are traditionally planar to restrict coil material and avoid coil losses. Here, we present a novel concept to model resonators partially in a plane with maximum sensitivity to the magnetic resonance signal and partially in an orthogonal plane with reduced signal sensitivity. Thus, properties of individual elements in coil arrays can be modified to optimize physical planar space and increase the sensitivity of the overall array. A particular case of the concept is implemented to decrease H-field destructive interferences in planar concentric in-phase arrays. An increase in signal to noise ratio of approximately 20% was achieved with two resonators placed over approximately the same planar area compared to common approaches at a target depth of 10 cm at 3 Tesla. Improved parallel imaging performance of this configuration is also demonstrated. The concept can be further used to increase coil density.

  4. Neutron resonance averaging

    SciTech Connect

    Chrien, R.E.

    1986-10-01

    The principles of resonance averaging as applied to neutron capture reactions are described. Several illustrations of resonance averaging to problems of nuclear structure and the distribution of radiative strength in nuclei are provided. 30 refs., 12 figs.

  5. Nanomechanical resonance detector

    DOEpatents

    Grossman, Jeffrey C; Zettl, Alexander K

    2013-10-29

    An embodiment of a nanomechanical frequency detector includes a support structure and a plurality of elongated nanostructures coupled to the support structure. Each of the elongated nanostructures has a particular resonant frequency. The plurality of elongated nanostructures has a range of resonant frequencies. An embodiment of a method of identifying an object includes introducing the object to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the object. An embodiment of a method of identifying a molecular species of the present invention includes introducing the molecular species to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the molecular species.

  6. Spectrum Analyzers Incorporating Tunable WGM Resonators

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry; Maleki, Lute

    2009-01-01

    A photonic instrument is proposed to boost the resolution for ultraviolet/ optical/infrared spectral analysis and spectral imaging allowing the detection of narrow (0.00007-to-0.07-picometer wavelength resolution range) optical spectral signatures of chemical elements in space and planetary atmospheres. The idea underlying the proposal is to exploit the advantageous spectral characteristics of whispering-gallery-mode (WGM) resonators to obtain spectral resolutions at least three orders of magnitude greater than those of optical spectrum analyzers now in use. Such high resolutions would enable measurement of spectral features that could not be resolved by prior instruments.

  7. MATHEMATICS OF SENSING, EXPLOITATION, AND EXECUTION (MSEE) Sensing, Exploitation, and Execution (SEE) on a Foundation for Representation, Inference, and Learning

    DTIC Science & Technology

    2016-07-01

    Representation, Inference, and Learning Song-Chun Zhu University of California Los Angeles JULY 2016 Final Report Approved for public release...EXPLOITATION, AND EXECUTION (MSEE) Sensing, Exploitation, and Execution (SEE) on a Foundation for Representation, Inference, and Learning 5a...mathematical foundation for unified representation, inference, and learning for ISR problems. The result of the project is an end-to-end system for scene and

  8. The Electric Giant Resonances

    NASA Astrophysics Data System (ADS)

    van der Woude, A.

    The following sections are included: * Introduction * Experimental Methods to Study Giant Resonances * Introduction * The Tools * Introduction * Tools for Isoscalar Scattering * INELASTIC α-SCATTERING * INELASTIC PROTON SCATTERING * Tools for Isovector Excitations * γ-ABSORPTION AND PARTICLE CAPTURE REACTIONS * CHARGE EXCHANGE REACTIONS - THE (π+, π0) REACTION * Tools For Isoscalar And Isovector Excitations * INELASTIC ELECTRON SCATTERING * GIANT RESONANCE EXCITATION BY FAST HEAVY IONS * From Multipole Cross Section To Multipole Strength * The Electric Isoscalar Resonances * The Isoscalar Giant Monopole Resonance * Systematics on the GMR * Compressibility and the Giant Monopole Resonance * Introduction * The Compressibility of nuclear matter from the GMR energies * Discussion * The Isoscalar Giant Quadrupole Resonance * General Trends In Medium-Heavy and Heavy Nuclei * The GQR In Light Nuclei * The Isoscalar 3- Strength, LEOR and HEOR * Isoscalar 4+ Strength * Miscellaneous; Isoscalar 1- and L > 4-Strength * The Electric Isovector Giant Resonances * The Isovector Giant Dipole Resonance: GDR * The Isovector Giant Monopole Resonances: IVGMR * The Isovector Quadrupole Resonance: IVGQR * The Effect of Ground State Deformation on the Shape of Giant Resonance: Microscopic Picture * Giant Resonances Built on Excited States * Introduction * Capture Reactions on Light Nuclei * Statistical decay of GDR γ Emission in Heavy Compound Systems * Introduction * Theoretical Predictions * Some Experimental Results * Summary and Outlook * Acknowledgements * General References * References

  9. Microwave Oscillators Based on Nonlinear WGM Resonators

    NASA Technical Reports Server (NTRS)

    Maleki, Lute; Matsko, Andrey; Savchenkov, Anatoliy; Strekalov, Dmitry

    2006-01-01

    Optical oscillators that exploit resonantly enhanced four-wave mixing in nonlinear whispering-gallery-mode (WGM) resonators are under investigation for potential utility as low-power, ultra-miniature sources of stable, spectrally pure microwave signals. There are numerous potential uses for such oscillators in radar systems, communication systems, and scientific instrumentation. The resonator in an oscillator of this type is made of a crystalline material that exhibits cubic Kerr nonlinearity, which supports the four-photon parametric process also known as four-wave mixing. The oscillator can be characterized as all-optical in the sense that the entire process of generation of the microwave signal takes place within the WGM resonator. The resonantly enhanced four-wave mixing yields coherent, phase-modulated optical signals at frequencies governed by the resonator structure. The frequency of the phase-modulation signal, which is in the microwave range, equals the difference between the frequencies of the optical signals; hence, this frequency is also governed by the resonator structure. Hence, further, the microwave signal is stable and can be used as a reference signal. The figure schematically depicts the apparatus used in a proof-of-principle experiment. Linearly polarized pump light was generated by an yttrium aluminum garnet laser at a wavelength of 1.32 microns. By use of a 90:10 fiber-optic splitter and optical fibers, some of the laser light was sent into a delay line and some was transmitted to one face of glass coupling prism, that, in turn, coupled the laser light into a crystalline CaF2 WGM disk resonator that had a resonance quality factor (Q) of 6x10(exp 9). The output light of the resonator was collected via another face of the coupling prism and a single-mode optical fiber, which transmitted the light to a 50:50 fiber-optic splitter. One output of this splitter was sent to a slow photodiode to obtain a DC signal for locking the laser to a particular

  10. The spherical birdcage resonator

    NASA Astrophysics Data System (ADS)

    Harpen, Michael D.

    A description of the operation of a spherical resonator capable of producing a uniform magnetic induction throughout a spherical volume is presented. Simple closed-form expressions for the spectrum of resonant frequencies are derived for both the low-pass and the high-pass configuration of the resonator and are shown to compare favorably with observation in an experimental coil system. It is shown that the spherical resonator produces a uniform spherical field of view when used as a magnetic resonance imaging radiofrequency coil.

  11. Ovenized microelectromechanical system (MEMS) resonator

    SciTech Connect

    Olsson, Roy H; Wojciechowski, Kenneth; Kim, Bongsang

    2014-03-11

    An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

  12. Investigating performance variability of processing, exploitation, and dissemination using a socio-technical systems analysis approach

    NASA Astrophysics Data System (ADS)

    Danczyk, Jennifer; Wollocko, Arthur; Farry, Michael; Voshell, Martin

    2016-05-01

    Data collection processes supporting Intelligence, Surveillance, and Reconnaissance (ISR) missions have recently undergone a technological transition accomplished by investment in sensor platforms. Various agencies have made these investments to increase the resolution, duration, and quality of data collection, to provide more relevant and recent data to warfighters. However, while sensor improvements have increased the volume of high-resolution data, they often fail to improve situational awareness and actionable intelligence for the warfighter because it lacks efficient Processing, Exploitation, and Dissemination and filtering methods for mission-relevant information needs. The volume of collected ISR data often overwhelms manual and automated processes in modern analysis enterprises, resulting in underexploited data, insufficient, or lack of answers to information requests. The outcome is a significant breakdown in the analytical workflow. To cope with this data overload, many intelligence organizations have sought to re-organize their general staffing requirements and workflows to enhance team communication and coordination, with hopes of exploiting as much high-value data as possible and understanding the value of actionable intelligence well before its relevance has passed. Through this effort we have taken a scholarly approach to this problem by studying the evolution of Processing, Exploitation, and Dissemination, with a specific focus on the Army's most recent evolutions using the Functional Resonance Analysis Method. This method investigates socio-technical processes by analyzing their intended functions and aspects to determine performance variabilities. Gaps are identified and recommendations about force structure and future R and D priorities to increase the throughput of the intelligence enterprise are discussed.

  13. Optical Helmholtz resonators

    NASA Astrophysics Data System (ADS)

    Chevalier, Paul; Bouchon, Patrick; Haïdar, Riad; Pardo, Fabrice

    2014-08-01

    Helmholtz resonators are widely used acoustic components able to select a single frequency. Here, based on an analogy between acoustics and electromagnetism wave equations, we present an electromagnetic 2D Helmholtz resonator made of a metallic slit-box structure. At the resonance, the light is funneled in the λ/800 apertures, and is subsequently absorbed in the cavity. As in acoustics, there is no higher order of resonance, which is an appealing feature for applications such as photodetection or thermal emission. Eventually, we demonstrate that the slit is of capacitive nature while the box behaves inductively. We derive an analytical formula for the resonance wavelength, which does not rely on wave propagation and therefore does not depend on the permittivity of the material filling the box. Besides, in contrast with half-wavelength resonators, the resonance wavelength can be engineered by both the slit aspect ratio and the box area.

  14. Resonance splitting in gyrotropic ring resonators.

    PubMed

    Jalas, Dirk; Petrov, Alexander; Krause, Michael; Hampe, Jan; Eich, Manfred

    2010-10-15

    We present the theoretical concept of an optical isolator based on resonance splitting in a silicon ring resonator covered with a magneto-optical polymer cladding. For this task, a perturbation method is derived for the modes in the cylindrical coordinate system. A polymer magneto-optical cladding causing a 0.01 amplitude of the off-diagonal element of the dielectric tensor is assumed. It is shown that the derived resonance splitting of the clockwise and counterclockwise modes increases for smaller ring radii. For the ring with a radius of approximately 1.5μm, a 29GHz splitting is demonstrated. An integrated optical isolator with a 10μm geometrical footprint is proposed based on a critically coupled ring resonator.

  15. Phase Matching of Diverse Modes in a WGM Resonator

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Strekalov, Dmitry; Yu, Nan; Matsko, Andrey; Mohageg, Makan; Maleki, Lute

    2008-01-01

    Phase matching of diverse electromagnetic modes (specifically, coexisting optical and microwave modes) in a whispering-gallery-mode (WGM) resonator has been predicted theoretically and verified experimentally. Such phase matching is necessary for storage of microwave/terahertz and optical electromagnetic energy in the same resonator, as needed for exploitation of nonlinear optical phenomena. WGM resonators are used in research on nonlinear optical phenomena at low optical intensities and as a basis for design and fabrication of novel optical devices. Examples of nonlinear optical phenomena recently demonstrated in WGM resonators include low-threshold Raman lasing, optomechanical oscillations, frequency doubling, and hyperparametric oscillations. The present findings regarding phase matching were made in research on low-threshold, strongly nondegenerate parametric oscillations in lithium niobate WGM resonators. The principle of operation of such an oscillator is rooted in two previously observed phenomena: (1) stimulated Raman scattering by polaritons in lithium niobate and (2) phase matching of nonlinear optical processes via geometrical confinement of light. The oscillator is partly similar to terahertz oscillators based on lithium niobate crystals, the key difference being that a novel geometrical configuration of this oscillator supports oscillation in the regime. The high resonance quality factors (Q values) typical of WGM resonators make it possible to achieve oscillation at a threshold signal level much lower than that in a non-WGM-resonator lithium niobate crystal.

  16. Demographic threats to the sustainability of Brazil nut exploitation.

    PubMed

    Peres, Carlos A; Baider, Claudia; Zuidema, Pieter A; Wadt, Lúcia H O; Kainer, Karen A; Gomes-Silva, Daisy A P; Salomão, Rafael P; Simões, Luciana L; Franciosi, Eduardo R N; Cornejo Valverde, Fernando; Gribel, Rogério; Shepard, Glenn H; Kanashiro, Milton; Coventry, Peter; Yu, Douglas W; Watkinson, Andrew R; Freckleton, Robert P

    2003-12-19

    A comparative analysis of 23 populations of the Brazil nut tree (Bertholletia excelsa) across the Brazilian, Peruvian, and Bolivian Amazon shows that the history and intensity of Brazil nut exploitation are major determinants of population size structure. Populations subjected to persistent levels of harvest lack juvenile trees less than 60 centimeters in diameter at breast height; only populations with a history of either light or recent exploitation contain large numbers of juvenile trees. A harvesting model confirms that intensive exploitation levels over the past century are such that juvenile recruitment is insufficient to maintain populations over the long term. Without management, intensively harvested populations will succumb to a process of senescence and demographic collapse, threatening this cornerstone of the Amazonian extractive economy.

  17. Wedge Waveguides and Resonators for Quantum Plasmonics.

    PubMed

    Kress, Stephan J P; Antolinez, Felipe V; Richner, Patrizia; Jayanti, Sriharsha V; Kim, David K; Prins, Ferry; Riedinger, Andreas; Fischer, Maximilian P C; Meyer, Stefan; McPeak, Kevin M; Poulikakos, Dimos; Norris, David J

    2015-09-09

    Plasmonic structures can provide deep-subwavelength electromagnetic fields that are useful for enhancing light-matter interactions. However, because these localized modes are also dissipative, structures that offer the best compromise between field confinement and loss have been sought. Metallic wedge waveguides were initially identified as an ideal candidate but have been largely abandoned because to date their experimental performance has been limited. We combine state-of-the-art metallic wedges with integrated reflectors and precisely placed colloidal quantum dots (down to the single-emitter level) and demonstrate quantum-plasmonic waveguides and resonators with performance approaching theoretical limits. By exploiting a nearly 10-fold improvement in wedge-plasmon propagation (19 μm at a vacuum wavelength, λvac, of 630 nm), efficient reflectors (93%), and effective coupling (estimated to be >70%) to highly emissive (~90%) quantum dots, we obtain Ag plasmonic resonators at visible wavelengths with quality factors approaching 200 (3.3 nm line widths). As our structures offer modal volumes down to ~0.004λvac(3) in an exposed single-mode waveguide-resonator geometry, they provide advantages over both traditional photonic microcavities and localized-plasmonic resonators for enhancing light-matter interactions. Our results confirm the promise of wedges for creating plasmonic devices and for studying coherent quantum-plasmonic effects such as long-distance plasmon-mediated entanglement and strong plasmon-matter coupling.

  18. Tunable Resonators for Nonlinear Modal Interactions.

    PubMed

    Ramini, Abdallah H; Hajjaj, Amal Z; Younis, Mohammad I

    2016-10-04

    Understanding the various mechanisms of nonlinear mode coupling in micro and nano resonators has become an imminent necessity for their successful implementation in practical applications. However, consistent, repeatable, and flexible experimental procedures to produce nonlinear mode coupling are lacking, and hence research into well-controlled experimental conditions is crucial. Here, we demonstrate well-controlled and repeatable experiments to study nonlinear mode coupling among micro and nano beam resonators. Such experimental approach can be applied to other micro and nano structures to help study their nonlinear interactions and exploit them for higher sensitive and less noisy responses. Using electrothermal tuning and electrostatic excitation, we demonstrate three different kinds of nonlinear interactions among the first and third bending modes of vibrations of slightly curved beams (arches): two-one internal resonance, three-one internal resonance, and mode veering (near crossing). The experimental procedure is repeatable, highly flexible, do not require special or precise fabrication, and is conducted in air and at room temperature. This approach can be applied to other micro and nano structures, which come naturally curved due to fabrication imperfections, such as CNTs, and hence lays the foundation to deeply investigate the nonlinear mode coupling in these structures in a consistent way.

  19. Tunable Resonators for Nonlinear Modal Interactions

    NASA Astrophysics Data System (ADS)

    Ramini, Abdallah H.; Hajjaj, Amal Z.; Younis, Mohammad I.

    2016-10-01

    Understanding the various mechanisms of nonlinear mode coupling in micro and nano resonators has become an imminent necessity for their successful implementation in practical applications. However, consistent, repeatable, and flexible experimental procedures to produce nonlinear mode coupling are lacking, and hence research into well-controlled experimental conditions is crucial. Here, we demonstrate well-controlled and repeatable experiments to study nonlinear mode coupling among micro and nano beam resonators. Such experimental approach can be applied to other micro and nano structures to help study their nonlinear interactions and exploit them for higher sensitive and less noisy responses. Using electrothermal tuning and electrostatic excitation, we demonstrate three different kinds of nonlinear interactions among the first and third bending modes of vibrations of slightly curved beams (arches): two-one internal resonance, three-one internal resonance, and mode veering (near crossing). The experimental procedure is repeatable, highly flexible, do not require special or precise fabrication, and is conducted in air and at room temperature. This approach can be applied to other micro and nano structures, which come naturally curved due to fabrication imperfections, such as CNTs, and hence lays the foundation to deeply investigate the nonlinear mode coupling in these structures in a consistent way.

  20. Lead-silicate glass optical microbubble resonator

    SciTech Connect

    Wang, Pengfei; Ward, Jonathan; Yang, Yong; Chormaic, Síle Nic; Feng, Xian; Brambilla, Gilberto; Farrell, Gerald

    2015-02-09

    Microbubble whispering gallery resonators have the potential to become key components in a variety of active and passive photonic circuit devices by offering a range of significant functionalities. Here, we report on the fabrication, optical characterization, and theoretical analysis of lead-silicate glass and optical microbubble resonators. Evanescent field coupling to the microbubbles was achieved using a 1 μm diameter, silica microfiber at a wavelength of circa 775 nm. High Q-factor modes were efficiently excited in both single-stem and two-stem, lead-silicate glass, and microbubble resonators, with bubble diameters of 38 μm (single-stem) and 48 μm (two-stem). Whispering gallery mode resonances with Q-factors as high as 2.3 × 10{sup 5} (single-stem) and 7 × 10{sup 6} (two-stem) were observed. By exploiting the high-nonlinearity of the lead-silicate glass, this work will act as a catalyst for studying a range of nonlinear optical effects in microbubbles, such as Raman scattering and four-wave mixing, at low optical powers.

  1. RESONANT CLUMPING AND SUBSTRUCTURE IN GALACTIC DISKS

    SciTech Connect

    Molloy, Matthew; Smith, Martin C.; Shen, Juntai; Evans, N. Wyn E-mail: msmith@shao.ac.cn E-mail: nwe@ast.cam.ac.uk

    2015-05-10

    We describe a method to extract resonant orbits from N-body simulations, exploiting the fact that they close in frames rotating with a constant pattern speed. Our method is applied to the N-body simulation of the Milky Way by Shen et al. This simulation hosts a massive bar, which drives strong resonances and persistent angular momentum exchange. Resonant orbits are found throughout the disk, both close to the bar and out to the very edges of the disk. Using Fourier spectrograms, we demonstrate that the bar is driving kinematic substructure even in the very outer parts of the disk. We identify two major orbit families in the outskirts of the disk, one of which makes significant contributions to the kinematic landscape, namely, the m:l = 3:−2 family, resonating with the bar. A mechanism is described that produces bimodal distributions of Galactocentric radial velocities at selected azimuths in the outer disk. It occurs as a result of the temporal coherence of particles on the 3:−2 resonant orbits, which causes them to arrive simultaneously at pericenter or apocenter. This resonant clumping, due to the in-phase motion of the particles through their epicycle, leads to both inward and outward moving groups that belong to the same orbital family and consequently produce bimodal radial velocity distributions. This is a possible explanation of the bimodal velocity distributions observed toward the Galactic anticenter by Liu et al. Another consequence is that transient overdensities appear and dissipate (in a symmetric fashion), resulting in a periodic pulsing of the disk’s surface density.

  2. Exploitation of a single species by a threshold management policy.

    PubMed

    Meza, Magno Enrique Mendoza; Costa, Michel Iskin da Silveira

    2011-11-01

    Continuous time models of single exploited populations usually generate outcomes expressing a dependence of yield and economic items on harvest intensity. In this work it is shown that a known threshold policy is able to generate yield and related economic items that do not depend on harvest intensity, but rather on the values of the population threshold itself and the species intrinsic parameters. It is argued that since this result can be carried over to other models of single species dynamics, it may have significant implications in the management and conservation of exploited populations.

  3. White-Light Whispering-Gallery-Mode Optical Resonators

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey; Savchenkov, Anatoliy; Maleki, Lute

    2006-01-01

    Whispering-gallery-mode (WGM) optical resonators can be designed to exhibit continuous spectra over wide wavelength bands (in effect, white-light spectra), with ultrahigh values of the resonance quality factor (Q) that are nearly independent of frequency. White-light WGM resonators have potential as superior alternatives to (1) larger, conventional optical resonators in ring-down spectroscopy, and (2) optical-resonator/electro-optical-modulator structures used in coupling of microwave and optical signals in atomic clocks. In these and other potential applications, the use of white-light WGM resonators makes it possible to relax the requirement of high-frequency stability of lasers, thereby enabling the use of cheaper lasers. In designing a white-light WGM resonator, one exploits the fact that the density of the mode spectrum increases predictably with the thickness of the resonator disk. By making the resonator disk sufficiently thick, one can make the frequency differences between adjacent modes significantly less than the spectral width of a single mode, so that the spectral peaks of adjacent modes overlap, making the resonator spectrum essentially continuous. Moreover, inasmuch as the Q values of the various modes are determined primarily by surface Rayleigh scattering that does not depend on mode numbers, all the modes have nearly equal Q. By use of a proper coupling technique, one can ensure excitation of a majority of the modes. For an experimental demonstration of a white-light WGM resonator, a resonator disk 0.5-mm thick and 5 mm in diameter was made from CaF2. The shape of the resonator and the fiberoptic coupling arrangement were as shown in Figure 1. The resonator was excited with laser light having a wavelength of 1,320 nm and a spectral width of 4 kHz. The coupling efficiency exceeded 80 percent at any frequency to which the laser could be set in its tuning range, which was >100-GHz wide. The resonator response was characterized by means of ring

  4. In vitro detection of beta amyloid exploiting surface enhanced Raman scattering (SERS) using a nanofluidic biosensor

    NASA Astrophysics Data System (ADS)

    Benford, Melodie E.; Chou, I.-Hsien; Beier, Hope T.; Wang, Miao; Kameoka, Jun; Good, Theresa A.; Coté, Gerard L.

    2008-02-01

    Alzheimer's disease (AD), a neurodegenerative disease and the most common cause of dementia, affects 4.5 million people according to the 2000 US census and is expected to triple to 13.2 million by the year 2050. Since no definitive pre-mortem tests exist to distinguish AD from mild cognitive impairment due to the natural aging process, we focus on detecting the beta amyloid (Aβ) protein, the primary component of the senile plaques characteristic of AD. We specifically detect cytotoxic species of Aβ by exploiting surface enhanced Raman scattering (SERS). Using a nanofluidic device with a bottleneck shape (a microchannel leading into a nanochannel); we trapped gold colloid particles (60 nm) at the entrance to the nanochannel, with Aβ restricted within the interstices between the aggregated nanoparticles. The continuous flow generated from pumping the solution into the device produced size-dependent trapping of the gold colloid particles, resulting in a high density of aggregated nanoparticles at this precise region, creating localized "hot spots" in the interstitial region between nanoparticles, and shifting the plasmon resonance to the near infrared region, in resonance with incident laser wavelength. With this robust sensing platform, we were able to obtain concentration-dependent SERS spectra of Aβ and of different proteins present in the cerebrospinal fluid of healthy people and people with Alzheimer's disease.

  5. From Exploitation to Industry: Definitions, Risks, and Consequences of Domestic Sexual Exploitation and Sex Work Among Women and Girls.

    PubMed

    Gerassi, Lara

    In the last 15 years, terms such as prostitution, sex trafficking, sexual exploitation, modern-day slavery, and sex work have elicited much confusion and debate as to their definitions. Consequently several challenges have emerged for both law enforcement in the prosecution of criminals and practitioners in service provision. This article reviews the state of the literature with regard to domestic, sexual exploitation among women and girls in the United States and seeks to (1) provide definitions and describe the complexity of all terms relating to domestic sexual exploitation of women and girls in the United States, (2) explore available national prevalence data according to the definitions provided, and (3) review the evidence of mental health, social, and structural risk factors at the micro-, mezzo-, and macrolevels.

  6. From Exploitation to Industry: Definitions, Risks, and Consequences of Domestic Sexual Exploitation and Sex Work Among Women and Girls

    PubMed Central

    Gerassi, Lara

    2015-01-01

    In the last 15 years, terms such as prostitution, sex trafficking, sexual exploitation, modern-day slavery, and sex work have elicited much confusion and debate as to their definitions. Consequently several challenges have emerged for both law enforcement in the prosecution of criminals and practitioners in service provision. This article reviews the state of the literature with regard to domestic, sexual exploitation among women and girls in the United States and seeks to (1) provide definitions and describe the complexity of all terms relating to domestic sexual exploitation of women and girls in the United States, (2) explore available national prevalence data according to the definitions provided, and (3) review the evidence of mental health, social, and structural risk factors at the micro-, mezzo-, and macrolevels. PMID:26726289

  7. Plasmon resonance enhanced mechanical detection of ligand binding

    SciTech Connect

    Ariyaratne, Amila; Zocchi, Giovanni

    2015-01-05

    Small molecule binding to the active site of enzymes typically modifies the mechanical stiffness of the enzyme. We exploit this effect, in a setup which combines nano-mechanics and surface plasmon resonance (SPR) enhanced optics, for the label free detection of ligand binding to an enzyme. The large dynamic range of the signal allows to easily obtain binding curves for small ligands, in contrast to traditional SPR methods which rely on small changes in index of refraction. Enzyme mechanics, assessed by nano-rheology, thus emerges as an alternative to electronic and spin resonances, assessed by traditional spectroscopies, for detecting ligand binding.

  8. Large mode radius resonators

    NASA Technical Reports Server (NTRS)

    Harris, Michael R.

    1987-01-01

    Resonator configurations permitting operation with large mode radius while maintaining good transverse mode discrimination are considered. Stable resonators incorporating an intracavity telescope and unstable resonator geometries utilizing an output coupler with a Gaussian reflectivity profile are shown to enable large radius single mode laser operation. Results of heterodyne studies of pulsed CO2 lasers with large (11mm e sup-2 radius) fundamental mode sizes are presented demonstrating minimal frequency sweeping in accordance with the theory of laser-induced medium perturbations.

  9. Exploitation of commercial remote sensing images: reality ignored?

    NASA Astrophysics Data System (ADS)

    Allen, Paul C.

    1999-12-01

    The remote sensing market is on the verge of being awash in commercial high-resolution images. Market estimates are based on the growing numbers of planned commercial remote sensing electro-optical, radar, and hyperspectral satellites and aircraft. EarthWatch, Space Imaging, SPOT, and RDL among others are all working towards launch and service of one to five meter panchromatic or radar-imaging satellites. Additionally, new advances in digital air surveillance and reconnaissance systems, both manned and unmanned, are also expected to expand the geospatial customer base. Regardless of platform, image type, or location, each system promises images with some combination of increased resolution, greater spectral coverage, reduced turn-around time (request-to- delivery), and/or reduced image cost. For the most part, however, market estimates for these new sources focus on the raw digital images (from collection to the ground station) while ignoring the requirements for a processing and exploitation infrastructure comprised of exploitation tools, exploitation training, library systems, and image management systems. From this it would appear the commercial imaging community has failed to learn the hard lessons of national government experience choosing instead to ignore reality and replicate the bias of collection over processing and exploitation. While this trend may be not impact the small quantity users that exist today it will certainly adversely affect the mid- to large-sized users of the future.

  10. Key points in biotechnological patents to be exploited.

    PubMed

    García, Alfredo Mateos; López-Moya, José Rafael; Ramos, Patricia

    2013-08-01

    Patents in some biotechnological fields are controversial. Despite this fact, the number of patent applications increases every year. Total revenues in the global biotechnology market are expected to increase in the middle term. Nowadays, the bioeconomy is an important socio-economic area, which is reflected in the number of firms dedicated to or using biotechnology. The exploitation of biotechnological patents is an essential task in the management of intellectual capital. This paper explains the multiplicity of factors that influence the exploitation of biotechnological patents; specifically, the internal and external key points of patents exploitation. The external determining factors for patents are: (i) the market need for biotechnological products and services, (ii) the importance of the freedom to operate analysis before entering the market, and (iii) efficiency in prosecution by Patent Offices. This paper primarily focuses on the internal determining factors, more particularly, the characteristics that the patent's owner must take into consideration in order to have a strong, broad subject-matter in the granted patent. The experimentation needed to obtain an adequate scope of the subject- matter in the claims is a critical issue in the exploitation of a patent or patent application.

  11. Exploiting a Molecular Gleason Grade for Prostate Cancer Therapy

    DTIC Science & Technology

    2010-03-01

    Exploiting a Molecular Gleason Grade for Prostate Cancer Therapy PRINCIPAL INVESTIGATOR: Peter S. Nelson, MD...Molecular Gleason Grade for Prostate Cancer Therapy 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-07-1-0149 5c. PROGRAM ELEMENT... levels of cognate serum proteins. #3 Write final report. (Note the original Aim 3 involving animal studies of altering prostate cancer grade

  12. Commercial Sexual Exploitation of Children and the School Nurse

    ERIC Educational Resources Information Center

    Grace, Lisa Goldblatt; Starck, Maureen; Potenza, Jane; Kenney, Patricia A.; Sheetz, Anne H.

    2012-01-01

    As trusted health professionals in the school setting, school nurses are well positioned to identify students who may be victims of commercial sexual exploitation of children (CSEC). However, until recently this issue has been clouded by lack of awareness, stigma, and/or denial. Since nationally the average age of entry for girls into the…

  13. The Sexual Exploitation of Missing Children: A Research Review.

    ERIC Educational Resources Information Center

    Hotaling, Gerald T.; Finkelhor, David

    This paper evaluates current knowledge about the prevalence, dynamics, and short- and long-term effects of sexual exploitation among missing children. It is based upon empirical research findings from books, papers presented at professional meetings, doctoral dissertations, works in progress, and more than 75 articles in professional journals.…

  14. Bats track and exploit changes in insect pest populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The role of bats or any generalist predator in suppressing prey populations depends on the predator’s ability to exploit available prey in space and time. Using a qPCR faecal DNA assay, we document significant association between numbers of Brazilian free-tailed bats (Tadarida brasiliensis) consumin...

  15. Risk assessment by dynamic representation of vulnerability, exploitation, and impact

    NASA Astrophysics Data System (ADS)

    Cam, Hasan

    2015-05-01

    Assessing and quantifying cyber risk accurately in real-time is essential to providing security and mission assurance in any system and network. This paper presents a modeling and dynamic analysis approach to assessing cyber risk of a network in real-time by representing dynamically its vulnerabilities, exploitations, and impact using integrated Bayesian network and Markov models. Given the set of vulnerabilities detected by a vulnerability scanner in a network, this paper addresses how its risk can be assessed by estimating in real-time the exploit likelihood and impact of vulnerability exploitation on the network, based on real-time observations and measurements over the network. The dynamic representation of the network in terms of its vulnerabilities, sensor measurements, and observations is constructed dynamically using the integrated Bayesian network and Markov models. The transition rates of outgoing and incoming links of states in hidden Markov models are used in determining exploit likelihood and impact of attacks, whereas emission rates help quantify the attack states of vulnerabilities. Simulation results show the quantification and evolving risk scores over time for individual and aggregated vulnerabilities of a network.

  16. [Medicinal plant resources of Trib. Isopyreae and prospects of exploitation].

    PubMed

    Qi, Yinde; Yang, Yongjian

    2002-02-01

    There are 17 species of medicinal plants from Trib. Isopyreae Schröd in China. This paper reports their resources, habitats and medicinal properties. On the basis of referring to the native and abroad medical studies on the plants from same Trilbe, their prospects of exploitation were advised.

  17. Improving the Complaint Process for Sexuality Exploited Clients.

    ERIC Educational Resources Information Center

    Spitalny, Gloria

    Four sexually exploited clients shared their experiences in invoking the complaint process against their former therapists. They wanted to stop the therapist from practicing and harming others, to receive some acknowledgement that they had been harmed, and to obtain some kind of recompense. If the therapist was unable to admit his or her error,…

  18. Hitch-hiking parasitic wasp learns to exploit butterfly antiaphrodisiac.

    PubMed

    Huigens, Martinus E; Pashalidou, Foteini G; Qian, Ming-Hui; Bukovinszky, Tibor; Smid, Hans M; van Loon, Joop J A; Dicke, Marcel; Fatouros, Nina E

    2009-01-20

    Many insects possess a sexual communication system that is vulnerable to chemical espionage by parasitic wasps. We recently discovered that a hitch-hiking (H) egg parasitoid exploits the antiaphrodisiac pheromone benzyl cyanide (BC) of the Large Cabbage White butterfly Pieris brassicae. This pheromone is passed from male butterflies to females during mating to render them less attractive to conspecific males. When the tiny parasitic wasp Trichogramma brassicae detects the antiaphrodisiac, it rides on a mated female butterfly to a host plant and then parasitizes her freshly laid eggs. The present study demonstrates that a closely related generalist wasp, Trichogramma evanescens, exploits BC in a similar way, but only after learning. Interestingly, the wasp learns to associate an H response to the odors of a mated female P. brassicae butterfly with reinforcement by parasitizing freshly laid butterfly eggs. Behavioral assays, before which we specifically inhibited long-term memory (LTM) formation with a translation inhibitor, reveal that the wasp has formed protein synthesis-dependent LTM at 24 h after learning. To our knowledge, the combination of associatively learning to exploit the sexual communication system of a host and the formation of protein synthesis-dependent LTM after a single learning event has not been documented before. We expect it to be widespread in nature, because it is highly adaptive in many species of egg parasitoids. Our finding of the exploitation of an antiaphrodisiac by multiple species of parasitic wasps suggests its use by Pieris butterflies to be under strong selective pressure.

  19. Confirmatory Factor Analysis of Perceived Exploitation of College Athletes Questionnaire

    ERIC Educational Resources Information Center

    Van Rheenen, Derek; Atwood, Jason R.

    2014-01-01

    The exploitation of college athletes has been a topic of controversy within American higher education for over half of a century. Especially in the revenue-generating sports of men's basketball and football, critics have highlighted the surplus gains expropriated by colleges and universities on the backs of these young men, who are…

  20. Beyond the Bravado: Sex Roles and the Exploitive Male.

    ERIC Educational Resources Information Center

    Taubman, Stan

    1986-01-01

    Examines the tendency of men to engage in domestic violence and sexual exploitation and presents male sex-role acquisition as a process of psychosocial violence against young boys, which creates a sense of shame, powerlessness, self-alienation, isolation from others, and retaliatory rage and inhibits capacities for intimacy and mutuality.…

  1. Exploiting link dynamics in LEO-to-ground communications

    SciTech Connect

    Palmer, Joseph Mcrae; Caffrey, Michael P

    2009-01-01

    The high dynamics of the LEO-to-ground radio channel are described. An analysis shows how current satellite radio systems largely underutilize the available radio link, and that a radio that can adaptively vary the bit rate can more fully exploit it, resulting in increased data throughput and improved power efficiency. We propose one method for implementing the adaptivity, and present simulation results.

  2. 77 FR 36491 - Request for Information Regarding Senior Financial Exploitation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-19

    ... From the Federal Register Online via the Government Publishing Office BUREAU OF CONSUMER FINANCIAL PROTECTION Request for Information Regarding Senior Financial Exploitation AGENCY: Bureau of Consumer Financial Protection. ACTION: Request for Information. SUMMARY: Section 1013(g)(1) of the Dodd-Frank...

  3. Conservation combats exploitation: choices within an evolutionary framework.

    PubMed

    Wang, X T; Li, Shu; Rao, Li-Lin

    2014-08-01

    Intentional change when viewed as making a risky or intertemporal choice with evolutionary relevance helps us understand its successes and its failures. To promote future-oriented ecological rationality requires establishing a linkage between nongenetic, cultural, and symbolic selections and genetic adaptations. Coupled with biophilic instinct, intentional conservation is more likely to prevail against evolved desires of environmental exploitation.

  4. Contraband Detection with Nuclear Resonance Fluorescence: Feasibility and Impact

    SciTech Connect

    Pruet, J; Lange, D

    2007-01-03

    In this report they show that cargo interrogation systems developed to thwart trafficking of illicit nuclear materials could also be powerful tools in the larger fight against contraband smuggling. In particular, in addition to detecting special nuclear materials, cargo scanning systems that exploit nuclear resonance fluorescence to detect specific isotopes can be used to help find: chemical weapons; some drugs as well as some chemicals regulated under the controlled substances act; precious metals; materials regulated under export control laws; and commonly trafficked fluorocarbons.

  5. On open electromagnetic resonators: relation between interferometers and resonators

    SciTech Connect

    Manenkov, Aleksandr A; Bykov, Vladimir P; Kuleshov, N V

    2010-05-26

    The physical difference between the concepts 'Fabry-Perot interferometer' and 'open resonator' is discussed. It is shown that the use of the term 'Fabry-Perot resonator' for open laser resonators is incorrect both from the historical viewpoint and from the viewpoint of the physical meaning of the processes occurring in these resonators. (laser beams and resonators)

  6. NASA Tech Briefs, March 2008

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Topics covered include: WRATS Integrated Data Acquisition System; Breadboard Signal Processor for Arraying DSN Antennas; Digital Receiver Phase Meter; Split-Block Waveguide Polarization Twist for 220 to 325 GHz; Nano-Multiplication-Region Avalanche Photodiodes and Arrays; Tailored Asymmetry for Enhanced Coupling to WGM Resonators; Disabling CNT Electronic Devices by Use of Electron Beams; Conical Bearingless Motor/Generators; Integrated Force Method for Indeterminate Structures; Carbon-Nanotube-Based Electrodes for Biomedical Applications; Compact Directional Microwave Antenna for Localized Heating; Using Hyperspectral Imagery to Identify Turfgrass Stresses; Shaping Diffraction-Grating Grooves to Optimize Efficiency; Low-Light-Shift Cesium Fountain without Mechanical Shutters; Magnetic Compensation for Second-Order Doppler Shift in LITS; Nanostructures Exploit Hybrid-Polariton Resonances; Microfluidics, Chromatography, and Atomic-Force Microscopy; Model of Image Artifacts from Dust Particles; Pattern-Recognition System for Approaching a Known Target; Orchestrator Telemetry Processing Pipeline; Scheme for Quantum Computing Immune to Decoherence; Spin-Stabilized Microsatellites with Solar Concentrators; Phase Calibration of Antenna Arrays Aimed at Spacecraft; Ring Bus Architecture for a Solid-State Recorder; and Image Compression Algorithm Altered to Improve Stereo Ranging.

  7. Frequency selective detection of nuclear quadrupole resonance (NQR) spin echoes

    NASA Astrophysics Data System (ADS)

    Somasundaram, Samuel D.; Jakobsson, Andreas; Smith, John A. S.; Althoefer, Kaspar A.

    2006-05-01

    Nuclear Quadrupole Resonance (NQR) is a radio frequency (RF) technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. The technique has been hampered by low signal-to-noise ratios and is further aggravated by the presence of RF interference (RFI). To ensure accurate detection, proposed detectors should exploit the rich form of the NQR signal. Furthermore, the detectors should also be robust to any remaining residual interference, left after suitable RFI mitigation has been employed. In this paper, we propose a new NQR data model, particularly for the realistic case where multiple pulse sequences are used to generate trains of spin echoes. Furthermore, we refine two recently proposed approximative maximum likelihood (AML) detectors, enabling the algorithm to optimally exploit the data model of the entire echo train and also incorporate knowledge of the temperature dependent spin-echo decay time. The AML-based detectors ensure accurate detection and robustness against residual RFI, even when the temperature of the sample is not precisely known, by exploiting the dependencies of the NQR resonant lines on temperature. Further robustness against residual interference is gained as the proposed detector is frequency selective; exploiting only those regions of the spectrum where the NQR signal is expected. Extensive numerical evaluations based on both simulated and measured NQR data indicate that the proposed Frequency selective Echo Train AML (FETAML) detector offers a significant improvement as compared to other existing detectors.

  8. Contact replacement for NMR resonance assignment

    PubMed Central

    Xiong, Fei; Pandurangan, Gopal; Bailey-Kellogg, Chris

    2008-01-01

    Motivation: Complementing its traditional role in structural studies of proteins, nuclear magnetic resonance (NMR) spectroscopy is playing an increasingly important role in functional studies. NMR dynamics experiments characterize motions involved in target recognition, ligand binding, etc., while NMR chemical shift perturbation experiments identify and localize protein–protein and protein–ligand interactions. The key bottleneck in these studies is to determine the backbone resonance assignment, which allows spectral peaks to be mapped to specific atoms. This article develops a novel approach to address that bottleneck, exploiting an available X-ray structure or homology model to assign the entire backbone from a set of relatively fast and cheap NMR experiments. Results: We formulate contact replacement for resonance assignment as the problem of computing correspondences between a contact graph representing the structure and an NMR graph representing the data; the NMR graph is a significantly corrupted, ambiguous version of the contact graph. We first show that by combining connectivity and amino acid type information, and exploiting the random structure of the noise, one can provably determine unique correspondences in polynomial time with high probability, even in the presence of significant noise (a constant number of noisy edges per vertex). We then detail an efficient randomized algorithm and show that, over a variety of experimental and synthetic datasets, it is robust to typical levels of structural variation (1–2 AA), noise (250–600%) and missings (10–40%). Our algorithm achieves very good overall assignment accuracy, above 80% in α-helices, 70% in β-sheets and 60% in loop regions. Availability: Our contact replacement algorithm is implemented in platform-independent Python code. The software can be freely obtained for academic use by request from the authors. Contact: gopal@cs.purdue.edu; cbk@cs.dartmouth.edu PMID:18586716

  9. The resonator handbook

    NASA Technical Reports Server (NTRS)

    Cook, Jerry D.; Zhou, Shiliang

    1993-01-01

    The purpose of this work is to extend resonator theory into the region in which the planar mirror is quite small. Results of the theoretical description are then extended to resonator design and experimental arrangements as discussed in further sections of this work. Finally, a discussion of dielectric measurements for small samples is included as a specific application of this work.

  10. The Concept of Resonance

    ERIC Educational Resources Information Center

    Truhlar, Donald G.

    2007-01-01

    A general example of a delocalization system associated with a higher energy than the localized one, which suggests that it is wrong to consider delocalization as equivalent to resonance stabilization, is presented. The meaning of resonance energy as it appears in valence bond theory is described as the lowering of the calculated ground-state…

  11. Resonant snubber inverter

    DOEpatents

    Lai, J.S.; Young, R.W. Sr.; Chen, D.; Scudiere, M.B.; Ott, G.W. Jr.; White, C.P.; McKeever, J.W.

    1997-06-24

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 14 figs.

  12. Monolithic MACS micro resonators

    NASA Astrophysics Data System (ADS)

    Lehmann-Horn, J. A.; Jacquinot, J.-F.; Ginefri, J. C.; Bonhomme, C.; Sakellariou, D.

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1 /√{ P } is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4 mm rotor at 500 MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials.

  13. Resonant snubber inverter

    DOEpatents

    Lai, Jih-Sheng; Young, Sr., Robert W.; Chen, Daoshen; Scudiere, Matthew B.; Ott, Jr., George W.; White, Clifford P.; McKeever, John W.

    1997-01-01

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  14. Resonant Flyby and Tour Design Using Heteroclinic Connections

    NASA Astrophysics Data System (ADS)

    Anderson, Rodney L.

    2012-05-01

    Tour design has traditionally relied on the use of two-body patched conic techniques in combination with differential correction or optimization algorithms. Recently, three-body effects have increasingly been included more directly in the design and analysis problem using a variety of different methods. In previous work it was shown that ballistic, impulsive, and low-thrust trajectories follow the invariant manifolds of unstable resonant and libration point orbits as they traverse resonances and approach the desired body in the circular restricted three-body problem (CRTBP). The invariant manifolds of these resonant orbits have now been used to compute heteroclinic connections between different resonant orbits. The heteroclinic connections have then been exploited to select particular flybys that travel between desired resonances, and sequences of heteroclinic connections have been chained together to obtain nearly ballistic trajectories that traverse the sequence of resonances. Approaches to the desired moon or planet have also been shown to heuristically follow both the invariant manifolds of unstable resonant and libration orbits in the planar problem. In particular, specific unstable manifolds of selected resonant orbits can be used to compute landing trajectories or approach desired orbits around the secondary in the CRTBP. The heteroclinic connections and approach analyses provide a framework for both designing trajectories traveling on a tour and analyzing the movement of objects through these resonances. The techniques also provide a means to form geometric and visual tools for analyzing and designing these types of trajectories. The current state of this research is described here, and particular examples of trajectories are presented. These trajectories may be used directly or as inputs to algorithms that can further refine the trajectory. The output from this process lays the foundation for reaching the goal of designing complete tours by chaining

  15. Exploring the resonant vibration of thin plates: Reconstruction of Chladni patterns and determination of resonant wave numbers.

    PubMed

    Tuan, P H; Wen, C P; Chiang, P Y; Yu, Y T; Liang, H C; Huang, K F; Chen, Y F

    2015-04-01

    The Chladni nodal line patterns and resonant frequencies for a thin plate excited by an electronically controlled mechanical oscillator are experimentally measured. Experimental results reveal that the resonant frequencies can be fairly obtained by means of probing the variation of the effective impedance of the exciter with and without the thin plate. The influence of the extra mass from the central exciter is confirmed to be insignificant in measuring the resonant frequencies of the present system. In the theoretical aspect, the inhomogeneous Helmholtz equation is exploited to derive the response function as a function of the driving wave number for reconstructing experimental Chladni patterns. The resonant wave numbers are theoretically identified with the maximum coupling efficiency as well as the maximum entropy principle. Substituting the theoretical resonant wave numbers into the derived response function, all experimental Chladni patterns can be excellently reconstructed. More importantly, the dispersion relationship for the flexural wave of the vibrating plate can be determined with the experimental resonant frequencies and the theoretical resonant wave numbers. The determined dispersion relationship is confirmed to agree very well with the formula of the Kirchhoff-Love plate theory.

  16. Control of the Dissipation Dynamics of Nanomechanical Resonator in Viscous Media

    DTIC Science & Technology

    2013-09-24

    REPORT Control of the dissipation dynamics of nanomechanical resonator in viscous media 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: This research aims...to quantify and control the dissipation dynamics of NEMS device in fluid and eventually recover the quality factor of NEMS device in fluid. Our...approach bases upon innovative modeling of micromechanical damping dynamics and exploitation of anti-damping in optomechanical resonators parametrically

  17. Strategies of exploitation of mammalian reservoirs by Bartonella species.

    PubMed

    Deng, Hongkuan; Le Rhun, Danielle; Buffet, Jean-Philippe R; Cotté, Violaine; Read, Amanda; Birtles, Richard J; Vayssier-Taussat, Muriel

    2012-02-27

    Numerous mammal species, including domestic and wild animals such as ruminants, dogs, cats and rodents, as well as humans, serve as reservoir hosts for various Bartonella species. Some of those species that exploit non-human mammals as reservoir hosts have zoonotic potential. Our understanding of interactions between bartonellae and reservoir hosts has been greatly improved by the development of animal models for infection and the use of molecular tools allowing large scale mutagenesis of Bartonella species. By reviewing and combining the results of these and other approaches we can obtain a comprehensive insight into the molecular interactions that underlie the exploitation of reservoir hosts by Bartonella species, particularly the well-studied interactions with vascular endothelial cells and erythrocytes.

  18. Exploitation of puddles for breakthroughs in claustrum research

    PubMed Central

    Johnson, John-Irwin; Fenske, Brian A.; Jaswa, Amar S.; Morris, John A.

    2014-01-01

    Since its first identification as a thin strip of gray matter enclosed between stretches of neighboring fiber bundles, the claustrum has been considered impossible to study by many modern techniques that need a certain roominess of tissue for their application. Known as the front wall, vormauren in German from 1822, and still called avant-mur in French, we here propose a means for breaking into and through this wall, by utilizing the instances where the claustral tissue itself has broken free into more spacious dimensions. This has occurred several times in the evolution of modern mammals, and all that needs be done is to exploit these natural expansions in order to take advantage of a great panoply of technological advances now at our disposal. So here we review the kinds of breakout “puddles” that await productive exploitation, to bring our knowledge of structure and function up to the level enjoyed for other more accessible regions of the brain. PMID:24860441

  19. Exploiting endobiotic metabolic pathways to target xenobiotic antioxidants to mitochondria.

    PubMed

    Anders, M W

    2013-09-01

    Oxidative stress plays a role in a range of human disease entities. Hence, strategies to target antioxidants to mitochondria are an active area of investigation. Triphenylphosphonium cation-based antioxidants and SS-peptides have been described and show significant uptake by mitochondria and effectiveness in animal models of conditions linked to oxidative stress. We tested the hypothesis that the mitochondrial β-oxidation pathway could be exploited to activate the antioxidant phenolic and methimazole prodrugs. Most compounds studied underwent mitochondrial biotransformation to release their antioxidant moieties, and some were cytoprotective in a hypoxia-reoxygenation model in rat cardiomyocytes. These results demonstrate the feasibility of exploiting mitochondrial bioactivation reactions for targeted drug delivery.

  20. Strategies of exploitation of mammalian reservoirs by Bartonella species

    PubMed Central

    2012-01-01

    Numerous mammal species, including domestic and wild animals such as ruminants, dogs, cats and rodents, as well as humans, serve as reservoir hosts for various Bartonella species. Some of those species that exploit non-human mammals as reservoir hosts have zoonotic potential. Our understanding of interactions between bartonellae and reservoir hosts has been greatly improved by the development of animal models for infection and the use of molecular tools allowing large scale mutagenesis of Bartonella species. By reviewing and combining the results of these and other approaches we can obtain a comprehensive insight into the molecular interactions that underlie the exploitation of reservoir hosts by Bartonella species, particularly the well-studied interactions with vascular endothelial cells and erythrocytes. PMID:22369683

  1. Violence and exploitation against women and girls with disability.

    PubMed

    Rosen, Daniel B

    2006-11-01

    This article seeks to explore issues concerning women and girls with disability who have experienced violence and exploitation. Owing to different methodologies of data collection, it is difficult to precisely determine the exact number of women and girls who are affected. The literature suggests that violence and exploitation against women and girls with disability occur at a rate 50% higher than in the rest of society. It also points out a number of additional critical issues: professionals are uneducated nd insensitive to the needs of these populations; increasing numbers of women and girls living with disability exacerbate the problem; women and girls with disability are uneducated about their rights and responsibilities; and action must be taken to halt this epidemic.

  2. Search in patchy media: Exploitation-exploration tradeoff

    NASA Astrophysics Data System (ADS)

    Chupeau, M.; Bénichou, O.; Redner, S.

    2017-01-01

    How to best exploit patchy resources? We introduce a minimal exploitation-migration model that incorporates the coupling between a searcher's trajectory, modeled by a random walk, and ensuing depletion of the environment by the searcher's consumption of resources. The searcher also migrates to a new patch when it takes S consecutive steps without finding resources. We compute the distribution of consumed resources Ft at time t for this non-Markovian searcher and show that consumption is maximized by exploring multiple patches. In one dimension, we derive the optimal strategy to maximize Ft. This strategy is robust with respect to the distribution of resources within patches and the criterion for leaving the current patch. We also show that Ft has an optimum in the ecologically relevant case of two-dimensional patchy environments.

  3. White Sharks Exploit the Sun during Predatory Approaches.

    PubMed

    Huveneers, Charlie; Holman, Dirk; Robbins, Rachel; Fox, Andrew; Endler, John A; Taylor, Alex H

    2015-04-01

    There is no conclusive evidence of any nonhuman animal using the sun as part of its predation strategy. Here, we show that the world's largest predatory fish-the white shark (Carcharodon carcharias)-exploits the sun when approaching baits by positioning the sun directly behind them. On sunny days, sharks reversed their direction of approach along an east-west axis from morning to afternoon but had uniformly distributed approach directions during overcast conditions. These results show that white sharks have sufficient behavioral flexibility to exploit fluctuating environmental features when predating. This sun-tracking predation strategy has a number of potential functional roles, including improvement of prey detection, avoidance of retinal overstimulation, and predator concealment.

  4. Lunar Resource Exploitation with Team Hakuto Swarm Rovers

    NASA Astrophysics Data System (ADS)

    Acierno, Kyle

    2016-07-01

    While much research has been done on the exploration, extraction and utilization of the Moon's resources, little attention has been given to exploring the economic opportunities that exist in the exploitation of those resources with the use of swam rovers. In order to develop a holistic view of lunar resources, this paper will first investigate the most important volatiles and minerals that are known to exist on the Moon. Next, Google Lunar XPRIZE Team Hakuto's technology and current robotic set up will be given. Finally, TEAM HAKUTO's 2017 Lunar mission plan will be outlined, providing an overview of future architectures using future swarm robotics to search for, map and eventually exploit the resources and volatiles.

  5. Exploitation of evolutionarily conserved amoeba and mammalian processes by Legionella.

    PubMed

    Al-Quadan, Tasneem; Price, Christopher T; Abu Kwaik, Yousef

    2012-06-01

    Legionella pneumophila proliferates within various protists and metazoan cells, where a cadre of ∼300 effectors is injected into the host cell by the defect in organelle trafficking/intracellular multiplication (Dot/Icm) type IVB translocation system. Interkingdom horizontal gene transfer of genes of protists and their subsequent convergent evolution to become translocated effectors has probably enabled L. pneumophila to adapt to the intracellular life within various protists and metazoan cells through exploitation of evolutionarily eukaryotic processes, such as endoplasmic reticulum-to-Golgi vesicle traffic, phosphoinositol metabolism, AMPylation, deAMPylation, prenylation, polyubiquitination, proteasomal degradation and cytosolic amino- and oligo-peptidases. This is highlighted by the ankyrin B (AnkB) F-box effector that exploits multiple conserved eukaryotic machineries to generate high levels of free amino acids as sources of carbon and energy essential for intracellular proliferation in protists and metazoan cells and for manifestation of pulmonary disease in mammals.

  6. The ESA Scientific Exploitation of Operational Missions element

    NASA Astrophysics Data System (ADS)

    Desnos, Yves-Louis; Regner, Peter; Delwart, Steven; Benveniste, Jerome; Engdahl, Marcus; Zehner, Claus; Mathieu, Pierre-Philippe; Bojkov, Bojan; Gascon, Ferran; Donlon, Craig; Davidson, Malcolm; Goryl, Philippe; Pinnock, Simon

    2015-04-01

    SEOM is a program element within the fourth period (2013-2017) of ESA's Earth Observation Envelope Programme (http://seom.esa.int/). The prime objective is to federate, support and expand the international research community that the ERS,ENVISAT and the Envelope programmes have built up over the last 25 years. It aims to further strengthen the leadership of the European Earth Observation research community by enabling them to extensively exploit future European operational EO missions. SEOM will enable the science community to address new scientific research that are opened by free and open access to data from operational EO missions. Based on community-wide recommendations for actions on key research issues, gathered through a series of international thematic workshops and scientific user consultation meetings, a work plan has been established and is approved every year by ESA Members States. The 2015 SEOM work plan is covering the organisation of three Science users consultation workshops for Sentinel1/3/5P , the launch of new R&D studies for scientific exploitation of the Sentinels, the development of open-source multi-mission scientific toolboxes, the organisation of advanced international training courses, summer schools and educational materials, as well as activities for promoting the scientific use of EO data. The first SEOM projects have been tendered since 2013 including the development of Sentinel toolboxes, advanced INSAR algorithms for Sentinel-1 TOPS data exploitation, Improved Atmospheric Spectroscopic data-base (IAS), as well as grouped studies for Sentinel-1, -2, and -3 land and ocean applications and studies for exploiting the synergy between the Sentinels. The status and first results from these SEOM projects will be presented and an outlook for upcoming SEOM studies will be given.

  7. Exploiting Lexical Regularities in Designing Natural Language Systems.

    DTIC Science & Technology

    1988-04-01

    ELEMENT. PROJECT. TASKN Artificial Inteligence Laboratory A1A4WR NTumet 0) 545 Technology Square Cambridge, MA 02139 Ln *t- CONTROLLING OFFICE NAME AND...RO-RI95 922 EXPLOITING LEXICAL REGULARITIES IN DESIGNING NATURAL 1/1 LANGUAGE SYSTENS(U) MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE...oes.ary and ftdou.Ip hr Nl wow" L,2This paper presents the lexical component of the START Question Answering system developed at the MIT Artificial

  8. Nonlinear Fano-Resonant Dielectric Metasurfaces

    SciTech Connect

    Yang, Yuanmu; Wang, Wenyi; Boulesbaa, Abdelaziz; Kravchenko, Ivan I.; Briggs, Dayrl P.; Puretzky, Alexander; Geohegan, David; Valentine, Jason

    2015-10-26

    Strong nonlinear light matter interaction is highly sought-after for a variety of applications including lasing and all-optical light modulation. Recently, resonant plasmonic structures have been considered promising candidates for enhancing nonlinear optical processes due to their ability to greatly enhance the optical near-field; however, their small mode volumes prevent the inherently large nonlinear susceptibility of the metal from being efficiently exploited. We present an alternative approach that utilizes a Fano-resonant silicon metasurface. The metasurface results in strong near-field enhancement within the volume of the silicon resonator while minimizing two photon absorption. Here, we measure a third harmonic generation enhancement factor of 1.5 105 with respect to an unpatterned silicon film and an absolute conversion efficiency of 1.2 10 6 with a peak pump intensity of 3.2 GW cm 2. The enhanced nonlinearity, combined with a sharp linear transmittance spectrum, results in transmission modulation with a modulation depth of 36%. Finally, the modulation mechanism is studied by pump probe experiments

  9. Nonlinear Fano-Resonant Dielectric Metasurfaces

    DOE PAGES

    Yang, Yuanmu; Wang, Wenyi; Boulesbaa, Abdelaziz; ...

    2015-10-26

    Strong nonlinear light matter interaction is highly sought-after for a variety of applications including lasing and all-optical light modulation. Recently, resonant plasmonic structures have been considered promising candidates for enhancing nonlinear optical processes due to their ability to greatly enhance the optical near-field; however, their small mode volumes prevent the inherently large nonlinear susceptibility of the metal from being efficiently exploited. We present an alternative approach that utilizes a Fano-resonant silicon metasurface. The metasurface results in strong near-field enhancement within the volume of the silicon resonator while minimizing two photon absorption. Here, we measure a third harmonic generation enhancement factormore » of 1.5 105 with respect to an unpatterned silicon film and an absolute conversion efficiency of 1.2 10 6 with a peak pump intensity of 3.2 GW cm 2. The enhanced nonlinearity, combined with a sharp linear transmittance spectrum, results in transmission modulation with a modulation depth of 36%. Finally, the modulation mechanism is studied by pump probe experiments« less

  10. Exploitation of genetically modified inoculants for industrial ecology applications.

    PubMed

    Morrissey, John P; Walsh, Ultan F; O'Donnell, Anne; Moënne-Loccoz, Yvan; O'Gara, Fergal

    2002-08-01

    The major growth seen in the biotechnology industry in recent decades has largely been driven by the exploitation of genetic engineering techniques. The initial benefits have been predominantly in the biomedical area, with products such as vaccines and hormones that have received broad public approval. In the environmental biotechnology and industrial ecology sectors, biotechnology has the potential to make significant advances through the use of genetically modified (GM) microbial inoculants that can reduce agri-chemical usage or remediate polluted environments. Although many GM inoculants have been developed and tested under laboratory conditions, commercial exploitation has lagged behind. Here, we review scientific and regulatory requirements that must be satisfied as part of that exploitation process. Particular attention is paid to new European Union (EU) regulations (Directives) that govern the testing and release of genetically modified organisms and microbial plant protection inoculants in the EU. With regard to the release of GM inoculants, the impact of the inoculant and the fate of modified genes are important concerns. Long term monitoring of release sites is necessary to address these issues. Data are reported from the monitoring of a site 6 years after release of GM Sinorhizobium meliloti strains. It was found that despite the absence of a host plant, the GM strains persisted in the soil for at least 6 years. Horizontal transfer and microevolution of a GM plasmid between S. meliloti strains was also observed. These data illustrate the importance of assessing the long-term persistence of GM inoculants.

  11. Host species exploitation and discrimination by animal parasites.

    PubMed

    Forbes, Mark R; Morrill, André; Schellinck, Jennifer

    2017-05-05

    Parasite species often show differential fitness on different host species. We developed an equation-based model to explore conditions favouring host species exploitation and discrimination. In our model, diploid infective stages randomly encountered hosts of two species; the parasite's relative fitness in exploiting each host species, and its ability to discriminate between them, was determined by the parasite's genotype at two independent diallelic loci. Relative host species frequency determined allele frequencies at the exploitation locus, whereas differential fitness and combined host density determined frequency of discrimination alleles. The model predicts instances where populations contain mixes of discriminatory and non-discriminatory infective stages. Also, non-discriminatory parasites should evolve when differential fitness is low to moderate and when combined host densities are low, but not so low as to cause parasite extinction. A corollary is that parasite discrimination (and host-specificity) increases with higher combined host densities. Instances in nature where parasites fail to discriminate when differential fitness is extreme could be explained by one host species evolving resistance, following from earlier selection for parasite non-discrimination. Similar results overall were obtained for haploid extensions of the model. Our model emulates multi-host associations and has implications for understanding broadening of host species ranges by parasites.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'.

  12. Harsh childhood environmental characteristics predict exploitation and retaliation in humans

    PubMed Central

    McCullough, Michael E.; Pedersen, Eric J.; Schroder, Jaclyn M.; Tabak, Benjamin A.; Carver, Charles S.

    2013-01-01

    Across and within societies, people vary in their propensities towards exploitative and retaliatory defection in potentially cooperative interaction. We hypothesized that this variation reflects adaptive responses to variation in cues during childhood that life will be harsh, unstable and short—cues that probabilistically indicate that it is in one's fitness interests to exploit co-operators and to retaliate quickly against defectors. Here, we show that childhood exposure to family neglect, conflict and violence, and to neighbourhood crime, were positively associated for men (but not women) with exploitation of an interaction partner and retaliatory defection after that partner began to defect. The associations between childhood environment and both forms of defection for men appeared to be mediated by participants' endorsement of a ‘code of honour’. These results suggest that individual differences in mutual benefit cooperation are not merely due to genetic noise, random developmental variation or the operation of domain-general cultural learning mechanisms, but rather, might reflect the adaptive calibration of social strategies to local social–ecological conditions. PMID:23118435

  13. Potentially exploitable supercritical geothermal resources in the ductile crust

    USGS Publications Warehouse

    Watanabe, Noriaki; Numakura, Tatsuya; Sakaguchi, Kiyotoshi; Saishu, Hanae; Okamoto, Atsushi; Ingebritsen, Steven E.; Tsuchiya, Noriyoshi

    2017-01-01

    The hypothesis that the brittle–ductile transition (BDT) drastically reduces permeability implies that potentially exploitable geothermal resources (permeability >10−16 m2) consisting of supercritical water could occur only in rocks with unusually high transition temperatures such as basalt. However, tensile fracturing is possible even in ductile rocks, and some permeability–depth relations proposed for the continental crust show no drastic permeability reduction at the BDT. Here we present experimental results suggesting that the BDT is not the first-order control on rock permeability, and that potentially exploitable resources may occur in rocks with much lower BDT temperatures, such as the granitic rocks that comprise the bulk of the continental crust. We find that permeability behaviour for fractured granite samples at 350–500 °C under effective confining stress is characterized by a transition from a weakly stress-dependent and reversible behaviour to a strongly stress-dependent and irreversible behaviour at a specific, temperature-dependent effective confining stress level. This transition is induced by onset of plastic normal deformation of the fracture surface (elastic–plastic transition) and, importantly, causes no ‘jump’ in the permeability. Empirical equations for this permeability behaviour suggest that potentially exploitable resources exceeding 450 °C may form at depths of 2–6 km even in the nominally ductile crust.

  14. Distinct Urban Mines: Exploiting secondary resources in unique anthropogenic spaces.

    PubMed

    Ongondo, F O; Williams, I D; Whitlock, G

    2015-11-01

    Fear of scarcity of resources highlight the need to exploit secondary materials from urban mines in the anthroposphere. Analogous to primary mines rich in one type of material (e.g. copper, gold, etc.), some urban mines are unique/distinct. We introduce, illustrate and discuss the concept of Distinct Urban Mines (DUM). Using the example of a university DUM in the UK, analogous to a primary mine, we illustrate potential product/material yields in respect of size, concentration and spatial location of the mine. Product ownership and replacement cycles for 17 high-value electrical and electronic equipment (EEE) among students showed that 20 tonnes of valuable e-waste were in stockpile in this DUM and a further 87 tonnes would 'soon' be available for exploitation. We address the opportunities and challenges of exploiting DUMs and conclude that they are readily available reservoirs for resource recovery. Two original contributions arise from this work: (i) a novel approach to urban mining with a potential for maximising resource recovery within the anthroposphere is conceptualised; and (ii) previously unavailable data for high-value products for a typical university DUM are presented and analysed.

  15. Potentially exploitable supercritical geothermal resources in the ductile crust

    NASA Astrophysics Data System (ADS)

    Watanabe, Noriaki; Numakura, Tatsuya; Sakaguchi, Kiyotoshi; Saishu, Hanae; Okamoto, Atsushi; Ingebritsen, Steven E.; Tsuchiya, Noriyoshi

    2017-01-01

    The hypothesis that the brittle-ductile transition (BDT) drastically reduces permeability implies that potentially exploitable geothermal resources (permeability >10-16 m2) consisting of supercritical water could occur only in rocks with unusually high transition temperatures such as basalt. However, tensile fracturing is possible even in ductile rocks, and some permeability-depth relations proposed for the continental crust show no drastic permeability reduction at the BDT. Here we present experimental results suggesting that the BDT is not the first-order control on rock permeability, and that potentially exploitable resources may occur in rocks with much lower BDT temperatures, such as the granitic rocks that comprise the bulk of the continental crust. We find that permeability behaviour for fractured granite samples at 350-500 °C under effective confining stress is characterized by a transition from a weakly stress-dependent and reversible behaviour to a strongly stress-dependent and irreversible behaviour at a specific, temperature-dependent effective confining stress level. This transition is induced by onset of plastic normal deformation of the fracture surface (elastic-plastic transition) and, importantly, causes no `jump' in the permeability. Empirical equations for this permeability behaviour suggest that potentially exploitable resources exceeding 450 °C may form at depths of 2-6 km even in the nominally ductile crust.

  16. Effects of Behavioural Strategy on the Exploitative Competition Dynamics.

    PubMed

    Nguyen-Ngoc, Doanh; Nguyen-Phuong, Thuy

    2016-12-01

    We investigate a system of two species exploiting a common resource. We consider both abiotic (i.e. with a constant resource supply rate) and biotic (i.e. with resource reproduction and self-limitation) resources. We are interested in the asymmetric competition where a given consumer is the locally superior resource exploiter (LSE) and the other is the locally inferior resource exploiter (LIE). They also interact directly via interference competition in the sense that LIE individuals can use two opposite strategies to compete with LSE individuals: we assume, in the first case, that LIE uses an avoiding strategy, i.e. LIE individuals go to a non-competition patch to avoids competition with LSE individuals, and in the second one, LIE uses an aggressive strategy, i.e. being very aggressive so that LSE individuals have to go to a non-competition patch. We further assume that there is no resource in the non-competition patch so that individuals have to come back to the competition patch for their maintenance, and the migration process acts on a fast time scale in comparison with demography and competition processes. The models show that being aggressive is efficient for LIE's survival and even provoke global extinction of the LSE and this result does not depend on the nature of resource.

  17. Relativistic quantum metrology: exploiting relativity to improve quantum measurement technologies.

    PubMed

    Ahmadi, Mehdi; Bruschi, David Edward; Sabín, Carlos; Adesso, Gerardo; Fuentes, Ivette

    2014-05-22

    We present a framework for relativistic quantum metrology that is useful for both Earth-based and space-based technologies. Quantum metrology has been so far successfully applied to design precision instruments such as clocks and sensors which outperform classical devices by exploiting quantum properties. There are advanced plans to implement these and other quantum technologies in space, for instance Space-QUEST and Space Optical Clock projects intend to implement quantum communications and quantum clocks at regimes where relativity starts to kick in. However, typical setups do not take into account the effects of relativity on quantum properties. To include and exploit these effects, we introduce techniques for the application of metrology to quantum field theory. Quantum field theory properly incorporates quantum theory and relativity, in particular, at regimes where space-based experiments take place. This framework allows for high precision estimation of parameters that appear in quantum field theory including proper times and accelerations. Indeed, the techniques can be applied to develop a novel generation of relativistic quantum technologies for gravimeters, clocks and sensors. As an example, we present a high precision device which in principle improves the state-of-the-art in quantum accelerometers by exploiting relativistic effects.

  18. Architectures for intelligent robots in the age of exploitation

    NASA Astrophysics Data System (ADS)

    Hall, E. L.; Ali, S. M. Alhaj; Ghaffari, M.; Liao, X.; Sarkar, Saurabh; Mathur, Kovid; Tennety, Srinivas

    2009-01-01

    History shows that problems that cause human confusion often lead to inventions to solve the problems, which then leads to exploitation of the invention, creating a confusion-invention-exploitation cycle. Robotics, which started as a new type of universal machine implemented with a computer controlled mechanism in the 1960's, has progressed from an Age of Over-expectation, a Time of Nightmare, an Age of Realism, and is now entering the Age of Exploitation. The purpose of this paper is to propose architecture for the modern intelligent robot in which sensors permit adaptation to changes in the environment are combined with a "creative controller" that permits adaptive critic, neural network learning, and a dynamic database that permits task selection and criteria adjustment. This ideal model may be compared to various controllers that have been implemented using Ethernet, CAN Bus and JAUS architectures and to modern, embedded, mobile computing architectures. Several prototypes and simulations are considered in view of peta-computing. The significance of this comparison is that it provides some insights that may be useful in designing future robots for various manufacturing, medical, and defense applications.

  19. Exploiting natural variation to identify insect-resistance genes.

    PubMed

    Broekgaarden, Colette; Snoeren, Tjeerd A L; Dicke, Marcel; Vosman, Ben

    2011-10-01

    Herbivorous insects are widespread and often serious constraints to crop production. The use of insect-resistant crops is a very effective way to control insect pests in agriculture, and the development of such crops can be greatly enhanced by knowledge on plant resistance mechanisms and the genes involved. Plants have evolved diverse ways to cope with insect attack that has resulted in natural variation for resistance towards herbivorous insects. Studying the molecular genetics and transcriptional background of this variation has facilitated the identification of resistance genes and processes that lead to resistance against insects. With the development of new technologies, molecular studies are not restricted to model plants anymore. This review addresses the need to exploit natural variation in resistance towards insects to increase our knowledge on resistance mechanisms and the genes involved. We will discuss how this knowledge can be exploited in breeding programmes to provide sustainable crop protection against insect pests. Additionally, we discuss the current status of genetic research on insect-resistance genes. We conclude that insect-resistance mechanisms are still unclear at the molecular level and that exploiting natural variation with novel technologies will contribute greatly to the development of insect-resistant crop varieties.

  20. Host species exploitation and discrimination by animal parasites

    PubMed Central

    Forbes, Mark R.; Morrill, André; Schellinck, Jennifer

    2017-01-01

    Parasite species often show differential fitness on different host species. We developed an equation-based model to explore conditions favouring host species exploitation and discrimination. In our model, diploid infective stages randomly encountered hosts of two species; the parasite's relative fitness in exploiting each host species, and its ability to discriminate between them, was determined by the parasite's genotype at two independent diallelic loci. Relative host species frequency determined allele frequencies at the exploitation locus, whereas differential fitness and combined host density determined frequency of discrimination alleles. The model predicts instances where populations contain mixes of discriminatory and non-discriminatory infective stages. Also, non-discriminatory parasites should evolve when differential fitness is low to moderate and when combined host densities are low, but not so low as to cause parasite extinction. A corollary is that parasite discrimination (and host-specificity) increases with higher combined host densities. Instances in nature where parasites fail to discriminate when differential fitness is extreme could be explained by one host species evolving resistance, following from earlier selection for parasite non-discrimination. Similar results overall were obtained for haploid extensions of the model. Our model emulates multi-host associations and has implications for understanding broadening of host species ranges by parasites. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’. PMID:28289258

  1. Combating sexual exploitation at the macro and micro levels.

    PubMed

    Perpinan, M S

    1998-01-01

    The Third World Movement against the Exploitation of Women (TW-MAE-W) is an international nongovernmental organization based in the Philippines which conducts advocacy upon global issues such as the root causes of exploitation and campaigns against sex tourism and military prostitution. TW-MAE-W began providing direct services at the local level in 1987, and now has 7 drop-in centers and 3 homes around the country, run by 35 female staff members. In addition, the Bethany Transition Home in Quezon City, Manila, houses 10-20 women, all who have outside employment. The girls and women who come to TW-MAE-W's facilities have all been exploited in some way. For example, they may be battered wives, women who have experienced incest, or girls who have been sold or tricked into prostitution. They arrive after either calling a telephone hotline on their own or being referred by social workers and nongovernmental organizations. Following an initial 3-month course of recuperation, center residents are helped to either continue their academic training, receive vocational training, or find a job. Basic health services are provided to the residents and drop-in center clients.

  2. Ultrasonic imaging of material flaws exploiting multipath information

    NASA Astrophysics Data System (ADS)

    Shen, Xizhong; Zhang, Yimin D.; Demirli, Ramazan; Amin, Moeness G.

    2011-05-01

    In this paper, we consider ultrasonic imaging for the visualization of flaws in a material. Ultrasonic imaging is a powerful nondestructive testing (NDT) tool which assesses material conditions via the detection, localization, and classification of flaws inside a structure. Multipath exploitations provide extended virtual array apertures and, in turn, enhance imaging capability beyond the limitation of traditional multisensor approaches. We utilize reflections of ultrasonic signals which occur when encountering different media and interior discontinuities. The waveforms observed at the physical as well as virtual sensors yield additional measurements corresponding to different aspect angles. Exploitation of multipath information addresses unique issues observed in ultrasonic imaging. (1) Utilization of physical and virtual sensors significantly extends the array aperture for image enhancement. (2) Multipath signals extend the angle of view of the narrow beamwidth of the ultrasound transducers, allowing improved visibility and array design flexibility. (3) Ultrasonic signals experience difficulty in penetrating a flaw, thus the aspect angle of the observation is limited unless access to other sides is available. The significant extension of the aperture makes it possible to yield flaw observation from multiple aspect angles. We show that data fusion of physical and virtual sensor data significantly improves the detection and localization performance. The effectiveness of the proposed multipath exploitation approach is demonstrated through experimental studies.

  3. Neanderthal exploitation of ibex and chamois in southwestern Europe.

    PubMed

    Yravedra, José; Cobo-Sánchez, Lucía

    2015-01-01

    There is increasing evidence that Neanderthals had a diverse and flexible diet. They exploited a wide range of resources from large proboscideans to small animals like turtles, rabbits, and marine species. Here, we discuss the importance of ibex and chamois in Neanderthal hunting strategies. The exploitation of both animals has traditionally been regarded as typical of Homo sapiens hunting behavior but was not a feature of Neanderthal behavior, which was thought to have focused on other kinds of game like deer, horses or large bovids. Our analysis of an extensive sample of Middle Paleolithic sites with faunal remains in the Iberian Peninsula reveals that Iberian ibex and chamois were frequently present throughout this period. Statistical analyses allowed us to assess the conditions that might have favored the presence or absence of these animals in the sites, while the taphonomic analyses enabled us to address the issue of whether ibex and chamois were indeed hunted by Neanderthals in the Iberian Peninsula. Our results indicate a better representation of both species in rocky and mountainous areas. The taphonomy of some sites reveals that chamois and ibex were hunted by Neanderthals, who showed great adaptive capacities to a wide variety of environments, including mountainous habitats. In contrast, other sites with favorable ecological conditions for ibex and chamois where these animals were not exploited by Neanderthals, who chose to hunt other species like deer, horses or aurochs, suggest behavioral complexity and large versatility.

  4. Quadrupole lattice resonances in plasmonic crystal excited by cylindrical vector beams

    PubMed Central

    Sakai, Kyosuke; Nomura, Kensuke; Yamamoto, Takeaki; Omura, Tatsuya; Sasaki, Keiji

    2016-01-01

    We report a scheme to exploit low radiative loss plasmonic resonance by combining a dark (subradiant) mode and a lattice resonance. We theoretically demonstrate that such dark-mode lattice resonances in periodic arrays of nanodisks or plasmonic crystals can be excited by vertically incident light beams. We investigate the excitation of lattice resonances in a finite sized, square-lattice plasmonic crystal by two types of cylindrical vector beams and a linearly polarized Gaussian beam. Quadrupole lattice resonances are excited by all three beams, and the largest peak intensity is obtained by using a specific type of cylindrical vector beam. Because of their lower radiative losses with many hotspots, the quadrupole lattice resonances in plasmonic crystal may pave the way for photonic research and applications that require strong light-matter interactions. PMID:27734923

  5. Quartz-enhanced photoacoustic spectroscopy exploiting tuning fork overtone modes

    NASA Astrophysics Data System (ADS)

    Sampaolo, A.; Patimisco, P.; Dong, L.; Geras, A.; Scamarcio, G.; Starecki, T.; Tittel, F. K.; Spagnolo, V.

    2015-12-01

    We report on a quartz-enhanced photoacoustic sensor (QEPAS) based on a custom-made quartz tuning fork (QTF) to operate in both the fundamental and the first overtone vibrational mode resonances. The QTF fundamental mode resonance falls at ˜3 kHz and the first overtone at ˜18 kHz. Electrical tests showed that the first overtone provides a higher quality factor and increased piezoelectric current peak values, with respect to the fundamental flexural mode. To evaluate the QTF acousto-electric energy conversion efficiency, we operated the QEPAS in the near-IR and selected water vapor as the target gas. The first overtone resonance provides a QEPAS signal-to-noise ratio ˜5 times greater with respect to that measured for the fundamental mode. These results open the way to employing QTF overtone vibrational modes for QEPAS based trace gas sensing.

  6. A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER).

    PubMed

    Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

    2016-09-14

    Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the (19)F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.

  7. A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER)

    NASA Astrophysics Data System (ADS)

    Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

    2016-09-01

    Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the 19F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.

  8. LABCOM resonator Phase 3

    SciTech Connect

    Keres, L.J.

    1990-11-01

    The purpose of this project was to develop quartz crystal resonator designs, production processes, and test capabilities for 5-MHz, 6.2-MHz, and 10-MHz resonators for Tactical Miniature Crystal Oscillator (TMXO) applications. GE Neutron Devices (GEND) established and demonstrated the capability to produce and test quartz crystal resonators for use in the TMXO developed by the US Army ERADCOM (now LABCOM). The goals in this project were based on the ERADCOM statement of work. The scope of work indicated that the resonator production facilities for this project would not be completely independent, but that they would be supported in part by equipment and processes in place at GEND used in US Department of Energy (DOE) work. In addition, provisions for production test equipment or or eventual technology transfer costs to a commercial supplier were clearly excluded from the scope of work. The demonstrated technical capability of the deep-etched blank design is feasible and practical. It can be manufactured in quantity with reasonable yield, and its performance is readily predictable. The ceramic flatpack is a very strong package with excellent hermeticity. The four-point mount supports the crystal to reasonable shock levels and does not perturb the resonator's natural frequency-temperature behavior. The package can be sealed with excellent yields. The high-temperature, high-vacuum processing developed for the TMXO resonator, including bonding the piezoid to its mount with conductive polyimide adhesive, is consistent with precision resonator fabrication. 1 fig., 6 tabs.

  9. The ESA Scientific Exploitation of Operational Missions element

    NASA Astrophysics Data System (ADS)

    Desnos, Yves-Louis; Benveniste, Jerome; Delwart, Steven; Engdahl, Marcus; Regner, Peter; Zehner, Claus; Mathieu, Pierre Philippe; Arino, Olivier; Bojkov, Bojan; Ferran, Gaston; Donlon, Craig; Kern, Michael; Scipal, Klaus

    2013-04-01

    The prime objective of the ESA Scientific Exploitation of Operational Missions (SEOM) programme element is to federate, support and expand the large international research community that the ERS, ENVISAT and the Envelope programmes have built up over the last 20 years. It aims to further strengthen the international leadership of European Earth Observation research community by enabling them to extensively exploit observations from future European operational EO missions. SEOM will enable the science community to address many new avenues of scientific research that will be opened by free and open access to data from operational EO missions. As a preparation for the SEOM element a series of international science users consultation has been organized by ESA in 2012 covering Sentinel 1 (FRINGE /SEASAR ), Sentinel 2 ( S2 symposium), Sentinel 3 (COAST-ALT workshop , 20 Years Progress in Radar Altimetry, Sentinel 3 OLCI/SLSTR 2012 workshop) and Sentinel 4-5 (Atmospheric Science Confrence). The science users recommendations have been gathered and form the basis for the work plan 2013 for the SEOM element. The SEOM element is organized along the following action lines: 1. Developing, validating and maintaining open-source, multi-mission, scientific software toolboxes capable to handle the Sentinels data products 2. Stimulating the development and validation of advanced EO methods and observation strategies in particular the new TOpS mode on Sentinel 1, the new band settings on Sentinel 2, the new geometry/bands of Sentinel 3 OLCI ,SLSTR intruments and the advanced delay-doppler (SAR) altimeter exploitation. 3. Continuing to federate, support and expand the multi-disciplinary expert EO research communities by organizing thematic workshops and ensuring high-quality scientific publications linked to these research domains. Promoting widespread scientific use of data. 4. Training the next generation of European EO scientists on the scientific exploitation of Sentinel s data

  10. Exploitation of marine gas hydrates: Benefits and risks (Invited)

    NASA Astrophysics Data System (ADS)

    Wallmann, K. J.

    2013-12-01

    Vast amounts of natural gas are stored in marine gas hydrates deposited at continental margins. The global inventory of carbon bound as methane in gas hydrates is currently estimated as 1000 × 500 Gt. Large-scale national research projects located mostly in South-East Asia but also in North America and Europe are aiming to exploit these ice-like solids as new unconventional resource of natural gas. Japan, South Korea and other Asian countries are taking the lead because their national waters harbor exploitable gas hydrate deposits which could be developed to reduce the dependency of these nations on costly LGN imports. In 2013, the first successful production test was performed off Japan at water depths of ca. 1000 m demonstrating that natural gas can be released and produced from marine hydrates by lowering the pressure in the sub-seabed hydrate reservoirs. In an alternative approach, CO2 from coal power plans and other industrial sources is used to release natural gas (methane) from hydrates while CO2 is bound and stored in the sub-surface as solid hydrate. These new approaches and technologies are still in an early pre-commercial phase; the costs of field development and gas production exceed the value of natural gas being produced from the slowly dissociating hydrates. However, new technologies are currently under development in the German SUGAR project and elsewhere to reduce costs and enhance gas production rates such that gas hydrates may become commercially exploitable over the coming decade(s). The exploitation of marine gas hydrates may help to reduce CO2 emissions from the fossil fuel sector if the produced natural gas is used to replace coal and/or LNG. Hydrate development could also provide important incentives for carbon capture technologies since CO2 can be used to produce natural gas from hydrates. However, leakage of gas may occur during the production process while slope failure may be induced by the accompanying dissociation/conversion of gas

  11. Spin Resonance Strength Calculations

    NASA Astrophysics Data System (ADS)

    Courant, E. D.

    2009-08-01

    In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.

  12. Resonances in UH

    SciTech Connect

    Badalyan, A.M.; Belova, T.I.; Konyukhova, N.B.; Efros, V.D.

    1985-06-01

    Resonances in UH are calculated using a microscopic approach with only central NN potentials. It is shown that there are broad resonances in the channels with S=1 and 0. P-wave resonances in UH are found at E/sub R/A 4.7-i2.7 MeV (S=1) and E/sub R/approx. = 6.4-i3.7 MeV (S=0) where the energy E is measured from the two-particle t + n threshold.

  13. Tunable multiwalled nanotube resonator

    DOEpatents

    Jensen, Kenneth J; Girit, Caglar O; Mickelson, William E; Zettl, Alexander K; Grossman, Jeffrey C

    2013-11-05

    A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

  14. Tunable multiwalled nanotube resonator

    DOEpatents

    Zettl, Alex K [Kensington, CA; Jensen, Kenneth J [Berkeley, CA; Girit, Caglar [Albany, CA; Mickelson, William E [San Francisco, CA; Grossman, Jeffrey C [Berkeley, CA

    2011-03-29

    A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

  15. Nuclear magnetic resonance spectroscopy with single spin sensitivity

    PubMed Central

    Müller, C.; Kong, X.; Cai, J.-M.; Melentijević, K.; Stacey, A.; Markham, M.; Twitchen, D.; Isoya, J.; Pezzagna, S.; Meijer, J.; Du, J. F.; Plenio, M. B.; Naydenov, B.; McGuinness, L. P.; Jelezko, F.

    2014-01-01

    Nuclear magnetic resonance spectroscopy and magnetic resonance imaging at the ultimate sensitivity limit of single molecules or single nuclear spins requires fundamentally new detection strategies. The strong coupling regime, when interaction between sensor and sample spins dominates all other interactions, is one such strategy. In this regime, classically forbidden detection of completely unpolarized nuclei is allowed, going beyond statistical fluctuations in magnetization. Here we realize strong coupling between an atomic (nitrogen–vacancy) sensor and sample nuclei to perform nuclear magnetic resonance on four 29Si spins. We exploit the field gradient created by the diamond atomic sensor, in concert with compressed sensing, to realize imaging protocols, enabling individual nuclei to be located with Angstrom precision. The achieved signal-to-noise ratio under ambient conditions allows single nuclear spin sensitivity to be achieved within seconds. PMID:25146503

  16. Nuclear quadrupole resonance detection of explosives: an overview

    NASA Astrophysics Data System (ADS)

    Miller, Joel B.

    2011-06-01

    Nuclear Quadrupole Resonance (NQR) is a spectroscopic technique closely related to Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). These techniques, and NQR in particular, induce signals from the material being interrogated that are very specific to the chemical and physical structure of the material, but are relatively insensitive to the physical form of the material. NQR explosives detection exploits this specificity to detect explosive materials, in contrast to other well known techniques that are designed to detect explosive devices. The past two decades have seen a large research and development effort in NQR explosives detection in the United States aimed at transportation security and military applications. Here, I will briefly describe the physical basis for NQR before discussing NQR developments over the past decade, with particular emphasis on landmine detection and the use of NQR in combating IED's. Potential future directions for NQR research and development are discussed.

  17. Surface-resistance measurements using superconducting stripline resonators.

    PubMed

    Hafner, Daniel; Dressel, Martin; Scheffler, Marc

    2014-01-01

    We present a method to measure the absolute surface resistance of conductive samples at a set of GHz frequencies with superconducting lead stripline resonators at temperatures 1-6 K. The stripline structure can easily be applied for bulk samples and allows direct calculation of the surface resistance without the requirement of additional calibration measurements or sample reference points. We further describe a correction method to reduce experimental background on high-Q resonance modes by exploiting TEM-properties of the external cabling. We then show applications of this method to the reference materials gold, tantalum, and tin, which include the anomalous skin effect and conventional superconductivity. Furthermore, we extract the complex optical conductivity for an all-lead stripline resonator to find a coherence peak and the superconducting gap of lead.

  18. A 10-GHz film-thickness-mode cavity optomechanical resonator

    NASA Astrophysics Data System (ADS)

    Han, Xu; Fong, King Y.; Tang, Hong X.

    2015-04-01

    We report on the advance of chip-scale cavity optomechanical resonators to beyond 10 GHz by exploiting the fundamental acoustic thickness mode of an aluminum nitride micro-disk. By engineering the mechanical anchor to minimize the acoustic loss, a quality factor of 1830 and hence a frequency-quality factor product of 1.9 × 1013 Hz are achieved in ambient air at room temperature. Actuated by strong piezo-electric force, the micro-disk resonator shows an excellent electro-optomechanical transduction efficiency. Our detailed analysis of the electro-optomechanical coupling allows identification and full quantification of various acoustic modes spanning from super-high to X-band microwave frequencies measured in the thin film resonator.

  19. A study of the main resonances outside the geostationary ring

    NASA Astrophysics Data System (ADS)

    Celletti, Alessandra; Galeş, Cătălin

    2015-08-01

    We investigate the dynamics of satellites and space debris in external resonances, namely in the region outside the geostationary ring. Precisely, we focus on the 1:2, 1:3, 2:3 resonances, which are located at about 66 931.4 km, 87 705.0 km, 55 250.7 km, respectively. Some of these resonances have been already exploited in space missions, like XMM-Newton and Integral. Our study is mainly based on a Hamiltonian approach, which allows us to get fast and reliable information on the dynamics in the resonant regions. Significative results are obtained even by considering just the effect of the geopotential in the Hamiltonian formulation. For objects (typically space debris) with high area-to-mass ratio the Hamiltonian includes also the effect of the solar radiation pressure. In addition, we perform a comparison with the numerical integration in Cartesian variables, including the geopotential, the gravitational attraction of Sun and Moon, and the solar radiation pressure. We implement some simple mathematical tools that allows us to get information on the terms which are dominant in the Fourier series expansion of the Hamiltonian around a given resonance, on the amplitude of the resonant islands and on the location of the equilibrium points. We also compute the Fast Lyapunov Indicators, which provide a cartography of the resonant regions, yielding the main dynamical features associated to the external resonances. We apply these techniques to analyze the 1:2, 1:3, 2:3 resonances; we consider also the case of objects with large area-to-mass ratio and we provide an application to the case studies given by XMM-Newton and Integral.

  20. Preventing Raman Lasing in High-Q WGM Resonators

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry; Maleki, Lute

    2007-01-01

    A generic design has been conceived to suppress the Raman effect in whispering- gallery-mode (WGM) optical resonators that have high values of the resonance quality factor (Q). Although it is possible to exploit the Raman effect (even striving to maximize the Raman gain to obtain Raman lasing), the present innovation is intended to satisfy a need that arises in applications in which the Raman effect inhibits the realization of the full potential of WGM resonators as frequency-selection components. Heretofore, in such applications, it has been necessary to operate high-Q WGM resonators at unattractively low power levels to prevent Raman lasing. (The Raman-lasing thresholds of WGM optical resonators are very low and are approximately proportional to Q(sup -2)). Heretofore, two ways of preventing Raman lasting at high power levels have been known, but both entail significant disadvantages: A resonator can be designed so that the optical field is spread over a relatively large mode volume to bring the power density below the threshold. For any given combination of Q and power level, there is certain mode volume wherein Raman lasing does not start. Unfortunately, a resonator that has a large mode volume also has a high spectral density, which is undesirable in a typical photonic application. A resonator can be cooled to the temperature of liquid helium, where the Raman spectrum is narrower and, therefore, the Raman gain is lower. However, liquid-helium cooling is inconvenient. The present design overcomes these disadvantages, making it possible to operate a low-spectral-density (even a single-mode) WGM resonator at a relatively high power level at room temperature, without risk of Raman lasing.

  1. Resonant ultrasound spectroscopy

    DOEpatents

    Migliori, Albert

    1991-01-01

    A resonant ultrasound spectroscopy method provides a unique characterization of an object for use in distinguishing similar objects having physical differences greater than a predetermined tolerance. A resonant response spectrum is obtained for a reference object by placing excitation and detection transducers at any accessible location on the object. The spectrum is analyzed to determine the number of resonant response peaks in a predetermined frequency interval. The distribution of the resonance frequencies is then characterized in a manner effective to form a unique signature of the object. In one characterization, a small frequency interval is defined and stepped though the spectrum frequency range. Subsequent objects are similarly characterized where the characterizations serve as signatures effective to distinguish objects that differ from the reference object by more than the predetermined tolerance.

  2. Electrically detected ferromagnetic resonance

    SciTech Connect

    Goennenwein, S. T. B.; Schink, S. W.; Brandlmaier, A.; Boger, A.; Opel, M.; Gross, R.; Keizer, R. S.; Klapwijk, T. M.; Gupta, A.; Huebl, H.; Bihler, C.; Brandt, M. S.

    2007-04-16

    We study the magnetoresistance properties of thin ferromagnetic CrO{sub 2} and Fe{sub 3}O{sub 4} films under microwave irradiation. Both the sheet resistance {rho} and the Hall voltage V{sub Hall} characteristically change when a ferromagnetic resonance (FMR) occurs in the film. The electrically detected ferromagnetic resonance (EDFMR) signals closely match the conventional FMR, measured simultaneously, in both resonance fields and line shapes. The sign and the magnitude of the resonant changes {delta}{rho}/{rho} and {delta}V{sub Hall}/V{sub Hall} can be consistently described in terms of a Joule heating effect. Bolometric EDFMR thus is a powerful tool for the investigation of magnetic anisotropy and magnetoresistive phenomena in ferromagnetic micro- or nanostructures.

  3. Micro-machined resonator

    DOEpatents

    Godshall, N.A.; Koehler, D.R.; Liang, A.Y.; Smith, B.K.

    1993-03-30

    A micro-machined resonator, typically quartz, with upper and lower micro-machinable support members, or covers, having etched wells which may be lined with conductive electrode material, between the support members is a quartz resonator having an energy trapping quartz mesa capacitively coupled to the electrode through a diaphragm; the quartz resonator is supported by either micro-machined cantilever springs or by thin layers extending over the surfaces of the support. If the diaphragm is rigid, clock applications are available, and if the diaphragm is resilient, then transducer applications can be achieved. Either the thin support layers or the conductive electrode material can be integral with the diaphragm. In any event, the covers are bonded to form a hermetic seal and the interior volume may be filled with a gas or may be evacuated. In addition, one or both of the covers may include oscillator and interface circuitry for the resonator.

  4. Micro-machined resonator

    DOEpatents

    Godshall, Ned A.; Koehler, Dale R.; Liang, Alan Y.; Smith, Bradley K.

    1993-01-01

    A micro-machined resonator, typically quartz, with upper and lower micro-machinable support members, or covers, having etched wells which may be lined with conductive electrode material, between the support members is a quartz resonator having an energy trapping quartz mesa capacitively coupled to the electrode through a diaphragm; the quartz resonator is supported by either micro-machined cantilever springs or by thin layers extending over the surfaces of the support. If the diaphragm is rigid, clock applications are available, and if the diaphragm is resilient, then transducer applications can be achieved. Either the thin support layers or the conductive electrode material can be integral with the diaphragm. In any event, the covers are bonded to form a hermetic seal and the interior volume may be filled with a gas or may be evacuated. In addition, one or both of the covers may include oscillator and interface circuitry for the resonator.

  5. Resonances in QCD

    SciTech Connect

    Lutz, Matthias F. M.; Lange, Jens Sören; Pennington, Michael; Bettoni, Diego; Brambilla, Nora; Crede, Volker; Eidelman, Simon; Gillitzer, Albrecht; Gradl, Wolfgang; Lang, Christian B.; Metag, Volker; Nakano, Takashi; Nieves, Juan; Neubert, Sebastian; Oka, Makoto; Olsen, Stephen L.; Pappagallo, Marco; Paul, Stephan; Pelizäus, Marc; Pilloni, Alessandro; Prencipe, Elisabetta; Ritman, Jim; Ryan, Sinead; Thoma, Ulrike; Uwer, Ulrich; Weise, Wolfram

    2016-04-01

    We report on the EMMI Rapid Reaction Task Force meeting 'Resonances in QCD', which took place at GSI October 12-14, 2015 (Fig.~1). A group of 26 people met to discuss the physics of resonances in QCD. The aim of the meeting was defined by the following three key questions; what is needed to understand the physics of resonances in QCD?; where does QCD lead us to expect resonances with exotic quantum numbers?; and what experimental efforts are required to arrive at a coherent picture? For light mesons and baryons only those with up, down and strange quark content were considered. For heavy-light and heavy-heavy meson systems, those with charm quarks were the focus.This document summarizes the discussions by the participants, which in turn led to the coherent conclusions we present here.

  6. Triple-resonant transducers.

    PubMed

    Butler, Stephen C

    2012-06-01

    A detailed analysis is presented of two novel multiple-resonant transducers which produce a wider transmit response than that of a conventional Tonpilz-type transducer. These multi-resonant transducers are Tonpilz-type longitudinal vibrators that produce three coupled resonances and are referred to as triple-resonant transducers (TRTs). One of these designs is a mechanical series arrangement of a tail mass, piezoelectric ceramic stack, central mass, compliant spring, second central mass, second compliant spring, and a piston-radiating head mass. The other TRT design is a mechanical series arrangement of a tail mass, piezoelectric ceramic stack, central mass, compliant spring, and head mass with a quarter-wave matching layer of poly(methyl methacrylate) on the head mass. Several prototype transducer element designs were fabricated that demonstrated proof-of-concept.

  7. Nuclear magnetic resonance gyroscope

    SciTech Connect

    Grover, B.C.

    1984-02-07

    A nuclear magnetic resonance gyro using two nuclear magnetic resonance gases, preferably xenon 129 and xenon 131, together with two alkaline metal vapors, preferably rubidium, potassium or cesium, one of the two alkaline metal vapors being pumped by light which has the wavelength of that alkaline metal vapor, and the other alkaline vapor being illuminated by light which has the wavelength of that other alkaline vapor.

  8. Hexagonal quartz resonator

    DOEpatents

    Peters, Roswell D. M.

    1982-01-01

    A generally flat, relatively thin AT-cut piezoelectric resonator element structured to minimize the force-frequency effect when mounted and energized in a housing. The resonator is in the form of an equilateral hexagon with the X crystallographic axis of the crystal passing through one set of opposing corners with mounting being effected at an adjacent set of corners respectively .+-.60.degree. away from the X axis which thereby results in a substantially zero frequency shift of the operating frequency.

  9. Injector with integrated resonator

    SciTech Connect

    Johnson, Thomas Edward; Ziminsky, Willy Steve; York, William David; Stevenson, Christian Xavier

    2014-07-29

    The system may include a turbine engine. The turbine engine may include a fuel nozzle. The fuel nozzle may include an air path. The fuel nozzle may also include a fuel path such that the fuel nozzle is in communication with a combustion zone of the turbine engine. Furthermore, the fuel nozzle may include a resonator. The resonator may be disposed in the fuel nozzle directly adjacent to the combustion zone.

  10. Resonant dielectric metamaterials

    DOEpatents

    Loui, Hung; Carroll, James; Clem, Paul G; Sinclair, Michael B

    2014-12-02

    A resonant dielectric metamaterial comprises a first and a second set of dielectric scattering particles (e.g., spheres) having different permittivities arranged in a cubic array. The array can be an ordered or randomized array of particles. The resonant dielectric metamaterials are low-loss 3D isotropic materials with negative permittivity and permeability. Such isotropic double negative materials offer polarization and direction independent electromagnetic wave propagation.

  11. Cylindrical laser resonator

    DOEpatents

    Casperson, Lee W.

    1976-02-24

    The properties of an improved class of lasers is presented. In one configuration of these lasers the radiation propagates radially within the amplifying medium, resulting in high fields and symmetric illumination at the resonator axis. Thus there is a strong focusing of energy at the axis of the resonator. In a second configuration the radiation propagates back and forth in a tubular region of space.

  12. Resonant nonlinear ultrasound spectroscopy

    DOEpatents

    Johnson, Paul A.; TenCate, James A.; Guyer, Robert A.; Van Den Abeele, Koen E. A.

    2001-01-01

    Components with defects are identified from the response to strains applied at acoustic and ultrasound frequencies. The relative resonance frequency shift .vertline..DELTA..function./.function..sub.0.vertline., is determined as a function of applied strain amplitude for an acceptable component, where .function..sub.0 is the frequency of the resonance peak at the lowest amplitude of applied strain and .DELTA..function. is the frequency shift of the resonance peak of a selected mode to determine a reference relationship. Then, the relative resonance frequency shift .vertline..DELTA..function./.function..sub.0 is determined as a function of applied strain for a component under test, where fo .function..sub.0 the frequency of the resonance peak at the lowest amplitude of applied strain and .DELTA..function. is the frequency shift of the resonance peak to determine a quality test relationship. The reference relationship is compared with the quality test relationship to determine the presence of defects in the component under test.

  13. Fano resonances in prism-coupled multimode square micropillar resonators

    NASA Astrophysics Data System (ADS)

    Lee, Ho-Tong; Zhou, Linjie; Poon, Andrew W.

    2005-06-01

    We report Fano resonances in a multimode square glass micropillar resonator; the resonances were obtained by using angle-resolved prism coupling. Our experiments reveal characteristically asymmetric line shapes of high-Q resonances and of detuned low-Q resonances in multimode reflection spectra. The asymmetric resonance line shapes evolve for an approximately pi phase within a 0.5° range of reflection angles. We model our observed asymmetric multimode resonances by the far-field interference between a light wave that is evanescently coupled with a high-Q mode orbit and a coherent light wave that is refractively coupled with a detuned low-Q mode orbit.

  14. Enhancing data exploitation through DTN-based data transmission protocols

    NASA Astrophysics Data System (ADS)

    Daglis, Ioannis A.; Tsaoussidis, Vassilis; Rontogiannis, Athanasios; Balasis, Georgios; Keramitsoglou, Iphigenia; Paronis, Dimitrios; Sykioti, Olga; Tsinganos, Antonios

    2014-05-01

    Data distribution and data access are major issues in space sciences and geosciences as they strongly influence the degree of data exploitation. Processing and analysis of large volumes of Earth observation and space/planetary data face two major impediments: limited access capabilities due to narrow connectivity windows between spacecraft and ground receiving stations and lack of sufficient communication and dissemination mechanisms between space data receiving centres and the end-user community. Real-time data assimilation that would be critical in a number of forecasting capabilities is particularly affected by such limitations. The FP7-Space project "Space-Data Routers" (SDR) has the aim of allowing space agencies, academic institutes and research centres to disseminate/share space data generated by single or multiple missions, in an efficient, secure and automated manner. The approach of SDR relies on space internetworking - and in particular on Delay-Tolerant Networking (DTN), which marks the new era in space communications, unifies space and earth communication infrastructures and delivers a set of tools and protocols for space-data exploitation. The project includes the definition of limitations imposed by typical space mission scenarios in which the National Observatory of Athens is currently involved, including space and planetary exploration, as well as satellite-supported geoscience applications. In this paper, we present the mission scenarios, the SDR-application and the evaluation of the associated impact from the space-data router enhancements. The work leading to this paper has received funding from the European Union's Seventh Framework Programme (FP7-SPACE-2010-1) under grant agreement no. 263330 for the SDR (Space-Data Routers for Exploiting Space Data) collaborative research project. This paper reflects only the authors' views and the Union is not liable for any use that may be made of the information contained therein.

  15. Entropy principle, non-regular processes, and generalized exploitation procedures

    NASA Astrophysics Data System (ADS)

    Triani, V.; Cimmelli, V. A.

    2012-06-01

    The classical Coleman-Noll approach to the exploitation of the entropy principle regards the classical balances of mass, linear and angular momentum and energy as differential constraints for the entropy inequality, and presupposes that the second law of thermodynamics is a restriction on the constitutive equations describing the material properties [B. D. Coleman and W. Noll, "The thermodynamics of elastic materials with heat conduction and viscosity," Arch. Rational Mech. Anal. 13, 167-178 (1963), 10.1007/BF01262690]. In 1996, Muschik and Ehrentraut proved that this presupposition may be confirmed by a rigorous proof, provided that an amendment to the classical second law of thermodynamics, which asserts that, except in equilibria, reversible process directions in state space do not exist, is postulated ["An amendment to the second law," J. Non-Equilib. Thermodyn. 21, 175-192 (1996), 10.1515/jnet.1996.21.2.175]. In their paper, the authors considered regular processes only. In a recent article [V. Triani and V. A. Cimmelli, "Interpretation of second law of thermodynamics in the presence of interfaces," Continuum. Mech. Thermodyn. 24, 165-174 (2012), 10.1007/s00161-011-0231-8], we proved that the result above remains valid in the presence of interfaces across which the unknown fields suffer jump discontinuities. Here, we show that the same conclusions achieved by Muschik and Ehrentraut and Triani and Cimmelli hold when the classical Coleman-Noll and Liu ["Method of Lagrange multipliers for exploitation of the entropy principle," Arch. Rational Mech. Anal. 46, 131-148 (1972), 10.1007/BF00250688] procedures for the exploitation of the second law, are generalized by considering also the gradients of the fundamental balance equations as constraints for the entropy inequality.

  16. Human Collective Intelligence under Dual Exploration-Exploitation Dilemmas

    PubMed Central

    Toyokawa, Wataru; Kim, Hye-rin; Kameda, Tatsuya

    2014-01-01

    The exploration-exploitation dilemma is a recurrent adaptive problem for humans as well as non-human animals. Given a fixed time/energy budget, every individual faces a fundamental trade-off between exploring for better resources and exploiting known resources to optimize overall performance under uncertainty. Colonies of eusocial insects are known to solve this dilemma successfully via evolved coordination mechanisms that function at the collective level. For humans and other non-eusocial species, however, this dilemma operates within individuals as well as between individuals, because group members may be motivated to take excessive advantage of others' exploratory findings through social learning. Thus, even though social learning can reduce collective exploration costs, the emergence of disproportionate “information scroungers” may severely undermine its potential benefits. We investigated experimentally whether social learning opportunities might improve the performance of human participants working on a “multi-armed bandit” problem in groups, where they could learn about each other's past choice behaviors. Results showed that, even though information scroungers emerged frequently in groups, social learning opportunities reduced total group exploration time while increasing harvesting from better options, and consequentially improved collective performance. Surprisingly, enriching social information by allowing participants to observe others' evaluations of chosen options (e.g., Amazon's 5-star rating system) in addition to choice-frequency information had a detrimental impact on performance compared to the simpler situation with only the choice-frequency information. These results indicate that humans groups can handle the fundamental “dual exploration-exploitation dilemmas” successfully, and that social learning about simple choice-frequencies can help produce collective intelligence. PMID:24755892

  17. Exploration and exploitation of Victorian science in Darwin's reading notebooks.

    PubMed

    Murdock, Jaimie; Allen, Colin; DeDeo, Simon

    2017-02-01

    Search in an environment with an uncertain distribution of resources involves a trade-off between exploitation of past discoveries and further exploration. This extends to information foraging, where a knowledge-seeker shifts between reading in depth and studying new domains. To study this decision-making process, we examine the reading choices made by one of the most celebrated scientists of the modern era: Charles Darwin. From the full-text of books listed in his chronologically-organized reading journals, we generate topic models to quantify his local (text-to-text) and global (text-to-past) reading decisions using Kullback-Liebler Divergence, a cognitively-validated, information-theoretic measure of relative surprise. Rather than a pattern of surprise-minimization, corresponding to a pure exploitation strategy, Darwin's behavior shifts from early exploitation to later exploration, seeking unusually high levels of cognitive surprise relative to previous eras. These shifts, detected by an unsupervised Bayesian model, correlate with major intellectual epochs of his career as identified both by qualitative scholarship and Darwin's own self-commentary. Our methods allow us to compare his consumption of texts with their publication order. We find Darwin's consumption more exploratory than the culture's production, suggesting that underneath gradual societal changes are the explorations of individual synthesis and discovery. Our quantitative methods advance the study of cognitive search through a framework for testing interactions between individual and collective behavior and between short- and long-term consumption choices. This novel application of topic modeling to characterize individual reading complements widespread studies of collective scientific behavior.

  18. Widespread exploitation of the honeybee by early Neolithic farmers.

    PubMed

    Roffet-Salque, Mélanie; Regert, Martine; Evershed, Richard P; Outram, Alan K; Cramp, Lucy J E; Decavallas, Orestes; Dunne, Julie; Gerbault, Pascale; Mileto, Simona; Mirabaud, Sigrid; Pääkkönen, Mirva; Smyth, Jessica; Šoberl, Lucija; Whelton, Helen L; Alday-Ruiz, Alfonso; Asplund, Henrik; Bartkowiak, Marta; Bayer-Niemeier, Eva; Belhouchet, Lotfi; Bernardini, Federico; Budja, Mihael; Cooney, Gabriel; Cubas, Miriam; Danaher, Ed M; Diniz, Mariana; Domboróczki, László; Fabbri, Cristina; González-Urquijo, Jesus E; Guilaine, Jean; Hachi, Slimane; Hartwell, Barrie N; Hofmann, Daniela; Hohle, Isabel; Ibáñez, Juan J; Karul, Necmi; Kherbouche, Farid; Kiely, Jacinta; Kotsakis, Kostas; Lueth, Friedrich; Mallory, James P; Manen, Claire; Marciniak, Arkadiusz; Maurice-Chabard, Brigitte; Mc Gonigle, Martin A; Mulazzani, Simone; Özdoğan, Mehmet; Perić, Olga S; Perić, Slaviša R; Petrasch, Jörg; Pétrequin, Anne-Marie; Pétrequin, Pierre; Poensgen, Ulrike; Pollard, C Joshua; Poplin, François; Radi, Giovanna; Stadler, Peter; Stäuble, Harald; Tasić, Nenad; Urem-Kotsou, Dushka; Vuković, Jasna B; Walsh, Fintan; Whittle, Alasdair; Wolfram, Sabine; Zapata-Peña, Lydia; Zoughlami, Jamel

    2015-11-12

    The pressures on honeybee (Apis mellifera) populations, resulting from threats by modern pesticides, parasites, predators and diseases, have raised awareness of the economic importance and critical role this insect plays in agricultural societies across the globe. However, the association of humans with A. mellifera predates post-industrial-revolution agriculture, as evidenced by the widespread presence of ancient Egyptian bee iconography dating to the Old Kingdom (approximately 2400 BC). There are also indications of Stone Age people harvesting bee products; for example, honey hunting is interpreted from rock art in a prehistoric Holocene context and a beeswax find in a pre-agriculturalist site. However, when and where the regular association of A. mellifera with agriculturalists emerged is unknown. One of the major products of A. mellifera is beeswax, which is composed of a complex suite of lipids including n-alkanes, n-alkanoic acids and fatty acyl wax esters. The composition is highly constant as it is determined genetically through the insect's biochemistry. Thus, the chemical 'fingerprint' of beeswax provides a reliable basis for detecting this commodity in organic residues preserved at archaeological sites, which we now use to trace the exploitation by humans of A. mellifera temporally and spatially. Here we present secure identifications of beeswax in lipid residues preserved in pottery vessels of Neolithic Old World farmers. The geographical range of bee product exploitation is traced in Neolithic Europe, the Near East and North Africa, providing the palaeoecological range of honeybees during prehistory. Temporally, we demonstrate that bee products were exploited continuously, and probably extensively in some regions, at least from the seventh millennium cal BC, likely fulfilling a variety of technological and cultural functions. The close association of A. mellifera with Neolithic farming communities dates to the early onset of agriculture and may provide

  19. Nonlinear Cherenkov difference-frequency generation exploiting birefringence of KTP

    SciTech Connect

    Ni, R.; Du, L.; Wu, Y.; Hu, X. P. Zou, J.; Zhang, Y.; Zhu, S. N.; Sheng, Y.; Arie, A.

    2016-01-18

    In this letter, we demonstrate the realization of nonlinear Cherenkov difference-frequency generation (CDFG) exploiting the birefringence property of KTiOPO{sub 4} (KTP) crystal. The pump and signal waves were set to be along different polarizations, thus the phase-matching requirement of CDFG, which is, the refractive index of the pump wave should be smaller than that of the signal wave, was fulfilled. The radiation angles and the intensity dependence of the CDFG on the pump wave were measured, which agreed well with the theoretical ones.

  20. Exploiting the Potential of Data Centers in the Smart Grid

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoying; Zhang, Yu-An; Liu, Xiaojing; Cao, Tengfei

    As the number of cloud computing data centers grows rapidly in recent years, from the perspective of smart grid, they are really large and noticeable electric load. In this paper, we focus on the important role and the potential of data centers as controllable loads in the smart grid. We reviewed relevant research in the area of letting data centers participate in the ancillary services market and demand response programs of the grid, and further investigate the possibility of exploiting the impact of data center placement on the grid. Various opportunities and challenges are summarized, which could provide more chances for researches to explore this field.

  1. Exploiting cytokines in adoptive T-cell therapy of cancer.

    PubMed

    Petrozziello, Elisabetta; Sturmheit, Tabea; Mondino, Anna

    2015-01-01

    Adoptive immunotherapy with tumor-reactive autologous T cells, either expanded from tumor specimens or genetically engineered to express tumor-reactive T-cell receptors and chimeric antigen receptors, is holding promising results in clinical trials. Several critical issues have been identified and results underline the possibility to exploit cytokines to further ameliorate the efficacy of current treatment protocols, also encompassing adoptive T-cell therapy. Here we review latest developments on the use of cytokines to better direct the nature of the T-cell infusion product, T-cell function and persistence in vivo, as well as to modulate the tumor microenvironment.

  2. On the Exploitation of Sensitivity Derivatives for Improving Sampling Methods

    NASA Technical Reports Server (NTRS)

    Cao, Yanzhao; Hussaini, M. Yousuff; Zang, Thomas A.

    2003-01-01

    Many application codes, such as finite-element structural analyses and computational fluid dynamics codes, are capable of producing many sensitivity derivatives at a small fraction of the cost of the underlying analysis. This paper describes a simple variance reduction method that exploits such inexpensive sensitivity derivatives to increase the accuracy of sampling methods. Three examples, including a finite-element structural analysis of an aircraft wing, are provided that illustrate an order of magnitude improvement in accuracy for both Monte Carlo and stratified sampling schemes.

  3. The ESA Scientific Exploitation of Operational Missions element, first results

    NASA Astrophysics Data System (ADS)

    Desnos, Yves-Louis; Regner, Peter; Delwart, Steven; Benveniste, Jerome; Engdahl, Marcus; Mathieu, Pierre-Philippe; Gascon, Ferran; Donlon, Craig; Davidson, Malcolm; Pinnock, Simon; Foumelis, Michael; Ramoino, Fabrizio

    2016-04-01

    SEOM is a program element within the fourth period (2013-2017) of ESA's Earth Observation Envelope Programme (http://seom.esa.int/). The prime objective is to federate, support and expand the international research community that the ERS, ENVISAT and the Envelope programmes have built up over the last 25 years. It aims to further strengthen the leadership of the European Earth Observation research community by enabling them to extensively exploit future European operational EO missions. SEOM will enable the science community to address new scientific research that are opened by free and open access to data from operational EO missions. Based on community-wide recommendations for actions on key research issues, gathered through a series of international thematic workshops and scientific user consultation meetings, a work plan is established and is approved every year by ESA Members States. During 2015 SEOM, Science users consultation workshops have been organized for Sentinel1/3/5P ( Fringe, S3 Symposium and Atmospheric science respectively) , new R&D studies for scientific exploitation of the Sentinels have been launched ( S3 for Science SAR Altimetry and Ocean Color , S2 for Science,) , open-source multi-mission scientific toolboxes have been launched (in particular the SNAP/S1-2-3 Toolbox). In addition two advanced international training courses have been organized in Europe to exploit the new S1-A and S2-A data for Land and Ocean remote sensing (over 120 participants from 25 countries) as well as activities for promoting the first scientific results ( e.g. Chili Earthquake) . In addition the First EO Open Science 2.0 was organised at ESA in October 2015 with 225 participants from 31 countries bringing together young EO scientists and data scientists. During the conference precursor activities in EO Open Science and Innovation were presented, while developing a Roadmap preparing for future ESA scientific exploitation activities. Within the conference, the first

  4. Poxvirus Exploitation of the Ubiquitin-Proteasome System

    PubMed Central

    Barry, Michele; van Buuren, Nicholas; Burles, Kristin; Mottet, Kelly; Wang, Qian; Teale, Alastair

    2010-01-01

    Ubiquitination plays a critical role in many cellular processes. A growing number of viruses have evolved strategies to exploit the ubiquitin-proteasome system, including members of the Poxviridae family. Members of the poxvirus family have recently been shown to encode BTB/kelch and ankyrin/F-box proteins that interact with cullin-3 and cullin-1 based ubiquitin ligases, respectively. Multiple members of the poxvirus family also encode ubiquitin ligases with intrinsic activity. This review describes the numerous mechanisms that poxviruses employ to manipulate the ubiquitin-proteasome system. PMID:21994622

  5. Exploiting geometric degrees of freedom in topological quantum computing

    SciTech Connect

    Xu Haitan; Wan Xin

    2009-07-15

    In a topological quantum computer, braids of non-Abelian anyons in a (2+1)-dimensional space time form quantum gates, whose fault tolerance relies on the topological, rather than geometric, properties of the braids. Here we propose to create and exploit redundant geometric degrees of freedom to improve the theoretical accuracy of topological single- and two-qubit quantum gates. We demonstrate the power of the idea using explicit constructions in the Fibonacci model. We compare its efficiency with that of the Solovay-Kitaev algorithm and explain its connection to the leakage errors reduction in an earlier construction [H. Xu and X. Wan, Phys. Rev. A 78, 042325 (2008)].

  6. Radiated Susceptibility Test Procedure and Setup Exploiting Crosstalk

    NASA Astrophysics Data System (ADS)

    Grassi, F.; Pignari, S. A.; Spadacini, G.; Bisognin, P.; Pelissou, P.; Marra, S.

    2016-05-01

    In this work, basic principles of an alternative test procedure exploiting crosstalk to reproduce in the terminal loads of a wiring structure the same disturbances that would be induced by traditional radiated susceptibility (RS) tests are presented. Equivalence with radiation is achieved by the use of a generator circuit properly fed with two synchronized RF generators, and holds for whatever loads (even not linear) connected to the terminations of the cable harness. The proposed procedure is here tailored to the specific conditions of incidence foreseen by aerospace Standards on RS. Its effectiveness is validated by measurements carried out in an ad hoc test setup.

  7. THz Pyro-Optical Detector Based on LiNbO₃ Whispering Gallery Mode Microdisc Resonator.

    PubMed

    Cosci, Alessandro; Cerminara, Matteo; Conti, Gualtiero Nunzi; Soria, Silvia; Righini, Giancarlo C; Pelli, Stefano

    2017-01-28

    This study analyzes the capabilities of a LiNbO₃ whispering gallery mode microdisc resonator as a potential bolometer detector in the THz range. The resonator is theoretically characterized in the stationary regime by its thermo-optic and thermal coefficients. Considering a Q-factor of 10⁷, a minimum detectable power of 20 μW was evaluated, three orders of magnitude above its noise equivalent power. This value opens up the feasibility of exploiting LiNbO₃ disc resonators as sensitive room-temperature detectors in the THz range.

  8. Capture probabilities for secondary resonances

    NASA Technical Reports Server (NTRS)

    Malhotra, Renu

    1990-01-01

    A perturbed pendulum model is used to analyze secondary resonances, and it is shown that a self-similarity between secondary and primary resonances exists. Henrard's (1982) theory is used to obtain formulas for the capture probability into secondary resonances. The tidal evolution of Miranda and Umbriel is considered as an example, and significant probabilities of capture into secondary resonances are found.

  9. Resonance frequency in ferromagnetic superlattices

    NASA Astrophysics Data System (ADS)

    Qiu, Rong-ke; Huang, An-dong; Li, Da; Zhang, Zhi-dong

    2011-10-01

    The resonance frequency in two-layer and three-layer ferromagnetic superlattices is studied, using the Callen's Green function method, the Tyablikov decoupling approximation and the Anderson-Callen decoupling approximation. The effects of interlayer exchange coupling, anisotropy, external magnetic field and temperature on the resonance frequency are investigated. It is found that the resonance frequencies increase with increasing external magnetic field. In a parameter region of the asymmetric system, each sublayer corresponds to its own resonance frequency. The anisotropy of a sublayer affects only the resonance frequency corresponding to this sublayer. The stronger the anisotropy, the higher is the resonance frequency. The interlayer exchange coupling affects only the resonance frequencies belonging to the sublayers connected by it. The stronger the interlayer exchange coupling, the higher are the resonance frequencies. All the resonance frequencies decrease as the reduced temperature increases. The results direct the method to enhance and adjust the resonance frequency of magnetic multilayered materials with a wide band.

  10. Three-way coexistence in obligate mutualist-exploiter interactions: the potential role of competition.

    PubMed

    Morris, William F; Bronstein, Judith L; Wilson, William G

    2003-06-01

    Many mutualisms host "exploiter" species that consume the benefits provided by one or both mutualists without reciprocating. Exploiters have been widely assumed to destabilize mutualisms, yet they are common. We develop models to explore conditions for local coexistence of obligate plant/pollinating seed parasite mutualisms and nonpollinating exploiters. As the larvae of both pollinators and (at a later time) exploiters consume seeds, we examine the importance of intraspecific and (asymmetric) interspecific competition among and between pollinators and exploiters for achieving three-way coexistence. With weak intra- and interspecific competition, exploiters can invade the stable mutualism and coexist with the mutualists (either stably or with oscillations), provided the exploiters' intrinsic birthrate (b(E)) slightly exceeds that of the pollinators. At higher b(E), all three species go locally extinct. When facing strong interspecific competition, exploiters cannot invade and coexist with the mutualists if intraspecific competition in pollinators and exploiters is weak. However, strong intraspecific competition in pollinators and exploiters facilitates exploiter invasion and coexistence and greatly expands the range of b(E) over which stable coexistence occurs. Our results suggest that mutualist/exploiter coexistence may be more easily achieved than previously thought, thus highlighting the need for a better understanding of competition among and between mutualists and exploiters.

  11. Not-so-resonant, resonant absorption

    NASA Astrophysics Data System (ADS)

    Brunel, F.

    1987-07-01

    When an intense electromagnetic wave is incident obliquely on a sharply bounded overdense plasma, strong energy absorption can be accounted for by the electrons that are dragged into the vacuum and sent back into the plasma with velocities v~=vosc. This mechanism is more efficient than usual resonant absorption for vosc/ω>L, with L being the density gradient length. In the very high-intensity CO2-laser-target interaction, this mechanism may account for most of the energy absorption.

  12. Symbiosis through exploitation and the merger of lineages in evolution

    PubMed Central

    Law, R.; Dieckmann, U.

    1998-01-01

    A model for the coevolution of two species in facultative symbiosis is used to investigate conditions under which species merge to form a single reproductive unit. Two traits evolve in each species, the first affecting loss of resources from an individual to its partner, and the second affecting vertical transmission of the symbiosis from one generation to the next. Initial conditions are set so that the symbiosis involves exploitation of one partner by the other and vertical transmission is very rare. It is shown that, even in the face of continuing exploitation, a stable symbiotic unit can evolve with maximum vertical transmission of the partners. Such evolution requires that eventually deaths should exceed births for both species in the free-living state, a condition which can be met if the victim, in the course of developing its defences, builds up sufficiently large costs in the free-living state. This result expands the set of initial conditions from which separate lineages can be expected to merge into symbiotic units.

  13. Herbivore exploits orally secreted bacteria to suppress plant defenses

    PubMed Central

    Chung, Seung Ho; Rosa, Cristina; Scully, Erin D.; Peiffer, Michelle; Tooker, John F.; Hoover, Kelli; Luthe, Dawn S.; Felton, Gary W.

    2013-01-01

    Induced plant defenses in response to herbivore attack are modulated by cross-talk between jasmonic acid (JA)- and salicylic acid (SA)-signaling pathways. Oral secretions from some insect herbivores contain effectors that overcome these antiherbivore defenses. Herbivores possess diverse microbes in their digestive systems and these microbial symbionts can modify plant–insect interactions; however, the specific role of herbivore-associated microbes in manipulating plant defenses remains unclear. Here, we demonstrate that Colorado potato beetle (Leptinotarsa decemlineata) larvae exploit bacteria in their oral secretions to suppress antiherbivore defenses in tomato (Solanum lycopersicum). We found that antibiotic-untreated larvae decreased production of JA and JA-responsive antiherbivore defenses, but increased SA accumulation and SA-responsive gene expression. Beetles benefit from down-regulating plant defenses by exhibiting enhanced larval growth. In SA-deficient plants, suppression was not observed, indicating that suppression of JA-regulated defenses depends on the SA-signaling pathway. Applying bacteria isolated from larval oral secretions to wounded plants confirmed that three microbial symbionts belonging to the genera Stenotrophomonas, Pseudomonas, and Enterobacter are responsible for defense suppression. Additionally, reinoculation of these bacteria to antibiotic-treated larvae restored their ability to suppress defenses. Flagellin isolated from Pseudomonas sp. was associated with defense suppression. Our findings show that the herbivore exploits symbiotic bacteria as a decoy to deceive plants into incorrectly perceiving the threat as microbial. By interfering with the normal perception of herbivory, beetles can evade antiherbivore defenses of its host. PMID:24019469

  14. Cheating by exploitation of developmental prestalk patterning in Dictyostelium discoideum.

    PubMed

    Khare, Anupama; Shaulsky, Gad

    2010-02-26

    The cooperative developmental system of the social amoeba Dictyostelium discoideum is susceptible to exploitation by cheaters-strains that make more than their fair share of spores in chimerae. Laboratory screens in Dictyostelium have shown that the genetic potential for facultative cheating is high, and field surveys have shown that cheaters are abundant in nature, but the cheating mechanisms are largely unknown. Here we describe cheater C (chtC), a strong facultative cheater mutant that cheats by affecting prestalk differentiation. The chtC gene is developmentally regulated and its mRNA becomes stalk-enriched at the end of development. chtC mutants are defective in maintaining the prestalk cell fate as some of their prestalk cells transdifferentiate into prespore cells, but that defect does not affect gross developmental morphology or sporulation efficiency. In chimerae between wild-type and chtC mutant cells, the wild-type cells preferentially give rise to prestalk cells, and the chtC mutants increase their representation in the spore mass. Mixing chtC mutants with other cell-type proportioning mutants revealed that the cheating is directly related to the prestalk-differentiation propensity of the victim. These findings illustrate that a cheater can victimize cooperative strains by exploiting an established developmental pathway.

  15. User-Driven Sampling Strategies in Image Exploitation

    DOE PAGES

    Harvey, Neal R.; Porter, Reid B.

    2013-12-23

    Visual analytics and interactive machine learning both try to leverage the complementary strengths of humans and machines to solve complex data exploitation tasks. These fields overlap most significantly when training is involved: the visualization or machine learning tool improves over time by exploiting observations of the human-computer interaction. This paper focuses on one aspect of the human-computer interaction that we call user-driven sampling strategies. Unlike relevance feedback and active learning sampling strategies, where the computer selects which data to label at each iteration, we investigate situations where the user selects which data is to be labeled at each iteration. User-drivenmore » sampling strategies can emerge in many visual analytics applications but they have not been fully developed in machine learning. We discovered that in user-driven sampling strategies suggest new theoretical and practical research questions for both visualization science and machine learning. In this paper we identify and quantify the potential benefits of these strategies in a practical image analysis application. We find user-driven sampling strategies can sometimes provide significant performance gains by steering tools towards local minima that have lower error than tools trained with all of the data. Furthermore, in preliminary experiments we find these performance gains are particularly pronounced when the user is experienced with the tool and application domain.« less

  16. User-driven sampling strategies in image exploitation

    NASA Astrophysics Data System (ADS)

    Harvey, Neal; Porter, Reid

    2013-12-01

    Visual analytics and interactive machine learning both try to leverage the complementary strengths of humans and machines to solve complex data exploitation tasks. These fields overlap most significantly when training is involved: the visualization or machine learning tool improves over time by exploiting observations of the human-computer interaction. This paper focuses on one aspect of the human-computer interaction that we call user-driven sampling strategies. Unlike relevance feedback and active learning sampling strategies, where the computer selects which data to label at each iteration, we investigate situations where the user selects which data is to be labeled at each iteration. User-driven sampling strategies can emerge in many visual analytics applications but they have not been fully developed in machine learning. User-driven sampling strategies suggest new theoretical and practical research questions for both visualization science and machine learning. In this paper we identify and quantify the potential benefits of these strategies in a practical image analysis application. We find user-driven sampling strategies can sometimes provide significant performance gains by steering tools towards local minima that have lower error than tools trained with all of the data. In preliminary experiments we find these performance gains are particularly pronounced when the user is experienced with the tool and application domain.

  17. User-Driven Sampling Strategies in Image Exploitation

    SciTech Connect

    Harvey, Neal R.; Porter, Reid B.

    2013-12-23

    Visual analytics and interactive machine learning both try to leverage the complementary strengths of humans and machines to solve complex data exploitation tasks. These fields overlap most significantly when training is involved: the visualization or machine learning tool improves over time by exploiting observations of the human-computer interaction. This paper focuses on one aspect of the human-computer interaction that we call user-driven sampling strategies. Unlike relevance feedback and active learning sampling strategies, where the computer selects which data to label at each iteration, we investigate situations where the user selects which data is to be labeled at each iteration. User-driven sampling strategies can emerge in many visual analytics applications but they have not been fully developed in machine learning. We discovered that in user-driven sampling strategies suggest new theoretical and practical research questions for both visualization science and machine learning. In this paper we identify and quantify the potential benefits of these strategies in a practical image analysis application. We find user-driven sampling strategies can sometimes provide significant performance gains by steering tools towards local minima that have lower error than tools trained with all of the data. Furthermore, in preliminary experiments we find these performance gains are particularly pronounced when the user is experienced with the tool and application domain.

  18. A case study of exploiting enterprise resource planning requirements

    NASA Astrophysics Data System (ADS)

    Niu, Nan; Jin, Mingzhou; Cheng, Jing-Ru C.

    2011-05-01

    The requirements engineering (RE) processes have become a key to conceptualising corporate-wide integrated solutions based on packaged enterprise resource planning (ERP) software. The RE literature has mainly focused on procuring the most suitable ERP package. Little is known about how an organisation exploits the chosen ERP RE model to frame the business application development. This article reports an exploratory case study of a key tenet of ERP RE adoption, namely that aligning business applications to the packaged RE model leads to integral practices and economic development. The case study analysed a series interrelated pilot projects developed for a business division of a large IT manufacturing and service company, using Oracle's appl1ication implementation method (AIM). The study indicated that AIM RE improved team collaboration and project management experience, but needed to make hidden assumptions explicit to support data visibility and integrity. Our study can direct researchers towards rigorous empirical evaluations of ERP RE adoption, collect experiences and lessons learned for practitioners, and help generate more effective and mature processes when exploiting ERP RE methods.

  19. Infomax Strategies for an Optimal Balance Between Exploration and Exploitation

    NASA Astrophysics Data System (ADS)

    Reddy, Gautam; Celani, Antonio; Vergassola, Massimo

    2016-06-01

    Proper balance between exploitation and exploration is what makes good decisions that achieve high reward, like payoff or evolutionary fitness. The Infomax principle postulates that maximization of information directs the function of diverse systems, from living systems to artificial neural networks. While specific applications turn out to be successful, the validity of information as a proxy for reward remains unclear. Here, we consider the multi-armed bandit decision problem, which features arms (slot-machines) of unknown probabilities of success and a player trying to maximize cumulative payoff by choosing the sequence of arms to play. We show that an Infomax strategy (Info-p) which optimally gathers information on the highest probability of success among the arms, saturates known optimal bounds and compares favorably to existing policies. Conversely, gathering information on the identity of the best arm in the bandit leads to a strategy that is vastly suboptimal in terms of payoff. The nature of the quantity selected for Infomax acquisition is then crucial for effective tradeoffs between exploration and exploitation.

  20. Exploiting GPUs in Virtual Machine for BioCloud

    PubMed Central

    Jo, Heeseung; Jeong, Jinkyu; Lee, Myoungho; Choi, Dong Hoon

    2013-01-01

    Recently, biological applications start to be reimplemented into the applications which exploit many cores of GPUs for better computation performance. Therefore, by providing virtualized GPUs to VMs in cloud computing environment, many biological applications will willingly move into cloud environment to enhance their computation performance and utilize infinite cloud computing resource while reducing expenses for computations. In this paper, we propose a BioCloud system architecture that enables VMs to use GPUs in cloud environment. Because much of the previous research has focused on the sharing mechanism of GPUs among VMs, they cannot achieve enough performance for biological applications of which computation throughput is more crucial rather than sharing. The proposed system exploits the pass-through mode of PCI express (PCI-E) channel. By making each VM be able to access underlying GPUs directly, applications can show almost the same performance as when those are in native environment. In addition, our scheme multiplexes GPUs by using hot plug-in/out device features of PCI-E channel. By adding or removing GPUs in each VM in on-demand manner, VMs in the same physical host can time-share their GPUs. We implemented the proposed system using the Xen VMM and NVIDIA GPUs and showed that our prototype is highly effective for biological GPU applications in cloud environment. PMID:23710465

  1. Exploiting olfactory learning in alien rats to protect birds’ eggs

    PubMed Central

    Price, Catherine J.; Banks, Peter B.

    2012-01-01

    Predators must ignore unhelpful background “noise” within information-rich environments and focus on useful cues of prey activity to forage efficiently. Learning to disregard unrewarding cues should happen quickly, weakening future interest in the cue. Prey odor, which is rapidly investigated by predators, may be particularly appropriate for testing whether consistently unrewarded cues are ignored, and whether such behavior can be exploited to benefit prey. Using wild free-ranging populations of black rats, Rattus rattus, an alien predator of global concern, we tested whether the application of bird-nesting odors before the introduction of artificial nests (odor preexposure), enhanced the survival of birds eggs (prey) compared with areas where prey and nesting odors were introduced concurrently. In areas where predators had encountered prey odor before prey being available, the subsequently introduced eggs showed 62% greater survival than in areas where prey and odor were introduced together. We suggest that black rats preexposed to prey odor learned to ignore the unrewarding cue, leading to a significant improvement in prey survival that held for the 7-d monitoring period. Exploiting rapid learning that underpins foraging decisions by manipulating sensory contexts offers a nonlethal, but effective approach to reducing undesirable predatory impacts. Techniques based on olfactory preexposure may provide prey with protection during critical periods of vulnerability, such as immediately following a prey reintroduction. These results also highlight the potential benefits to species conservation to be gained from a greater understanding of the cognitive mechanisms driving alien predator behavior within ecological contexts. PMID:23071301

  2. Salmonella Typhimurium exploits inflammation to its own advantage in piglets

    PubMed Central

    Chirullo, Barbara; Pesciaroli, Michele; Drumo, Rosanna; Ruggeri, Jessica; Razzuoli, Elisabetta; Pistoia, Claudia; Petrucci, Paola; Martinelli, Nicola; Cucco, Lucilla; Moscati, Livia; Amadori, Massimo; Magistrali, Chiara F.; Alborali, Giovanni L.; Pasquali, Paolo

    2015-01-01

    Salmonella Typhimurium (S. Typhimurium) is responsible for foodborne zoonotic infections that, in humans, induce self-limiting gastroenteritis. The aim of this study was to evaluate whether the wild-type strain S. Typhimurium (STM14028) is able to exploit inflammation fostering an active infection. Due to the similarity between human and porcine diseases induced by S. Typhimurium, we used piglets as a model for salmonellosis and gastrointestinal research. This study showed that STM14028 is able to efficiently colonize in vitro porcine mono-macrophages and intestinal columnar epithelial (IPEC-J2) cells, and that the colonization significantly increases with LPS pre-treatment. This increase was then reversed by inhibiting the LPS stimulation through LPS antagonist, confirming an active role of LPS stimulation in STM14028-intracellular colonization. Moreover, LPS in vivo treatment increased cytokines blood level and body temperature at 4 h post infection, which is consistent with an acute inflammatory stimulus, capable to influence the colonization of STM14028 in different organs and tissues. The present study proves for the first time that in acute enteric salmonellosis, S. Typhimurium exploits inflammation for its benefit in piglets. PMID:26441914

  3. Exploiting first-class arrays in Fortran for accelerator programming

    SciTech Connect

    Rasmussen, Craig E; Weseloh, Wayne N; Robey, Robert W; Matthew, Sottile J; Quinlan, Daniel; Overbye, Jeffrey

    2010-12-15

    Emerging architectures for high performance computing often are well suited to a data parallel programming model. This paper presents a simple programming methodology based on existing languages and compiler tools that allows programmers to take advantage of these systems. We will work with the array features of Fortran 90 to show how this infrequently exploited, standardized language feature is easily transformed to lower level accelerator code. Our transformations are based on a mapping from Fortran 90 to C++ code with OpenCL extensions. The sheer complexity of programming for clusters of many or multi-core processors with tens of millions threads of execution make the simplicity of the data parallel model attractive. Furthermore, the increasing complexity of todays applications (especially when convolved with the increasing complexity of the hardware) and the need for portability across hardware architectures make a higher-level and simpler programming model like data parallel attractive. The goal of this work has been to exploit source-to-source transformations that allow programmers to develop and maintain programs at a high-level of abstraction, without coding to a specific hardware architecture. Furthermore these transformations allow multiple hardware architectures to be targeted without changing the high-level source. It also removes the necessity for application programmers to understand details of the accelerator architecture or to know OpenCL.

  4. Exploiting prior knowledge in compressed sensing wireless ECG systems.

    PubMed

    Polanía, Luisa F; Carrillo, Rafael E; Blanco-Velasco, Manuel; Barner, Kenneth E

    2015-03-01

    Recent results in telecardiology show that compressed sensing (CS) is a promising tool to lower energy consumption in wireless body area networks for electrocardiogram (ECG) monitoring. However, the performance of current CS-based algorithms, in terms of compression rate and reconstruction quality of the ECG, still falls short of the performance attained by state-of-the-art wavelet-based algorithms. In this paper, we propose to exploit the structure of the wavelet representation of the ECG signal to boost the performance of CS-based methods for compression and reconstruction of ECG signals. More precisely, we incorporate prior information about the wavelet dependencies across scales into the reconstruction algorithms and exploit the high fraction of common support of the wavelet coefficients of consecutive ECG segments. Experimental results utilizing the MIT-BIH Arrhythmia Database show that significant performance gains, in terms of compression rate and reconstruction quality, can be obtained by the proposed algorithms compared to current CS-based methods.

  5. Characterization of CRISPR RNA transcription by exploiting stranded metatranscriptomic data

    PubMed Central

    Ye, Yuzhen; Zhang, Quan

    2016-01-01

    CRISPR–Cas systems are bacterial adaptive immune systems, each typically composed of a locus of cas genes and a CRISPR array of spacers flanked by repeats. Processed transcripts of CRISPR arrays (crRNAs) play important roles in the interference process mediated by these systems, guiding targeted immunity. Here we developed computational approaches that allow us to characterize the expression of many CRISPRs in their natural environments, using community RNA-seq (metatranscriptomic) data. By exploiting public human gut metatranscriptomic data sets, we studied the expression of 56 repeat-sequence types of CRISPRs, revealing that most CRISPRs are transcribed in one direction (producing crRNAs). In rarer cases, including a type II system associated with Bacteroides fragilis, CRISPRs are transcribed in both directions. Type III CRISPR–Cas systems were found in the microbiomes, but metatranscriptomic reads were barely found for their CRISPRs. We observed individual-level variation of the crRNA transcription, and an even greater transcription of a CRISPR from the antisense strand than the crRNA strand in one sample. The orientations of CRISPR expression implicated by metatranscriptomic data are largely in agreement with prior predictions for CRISPRs, with exceptions. Our study shows the promise of exploiting community RNA-seq data for investigating the transcription of CRISPR–Cas systems. PMID:27190232

  6. Line segment matching and reconstruction via exploiting coplanar cues

    NASA Astrophysics Data System (ADS)

    Li, Kai; Yao, Jian

    2017-03-01

    This paper introduces a new system for reconstructing 3D scenes from Line Segments (LS) on images. A new LS matching algorithm and a novel 3D LS reconstruction algorithm are incorporated into the system. Two coplanar cues that indicates image LSs are coplanar in physical (3D) space are extensively exploited in both algorithms: (1) adjacent image LSs are coplanar in space in a high possibility; (2) the projections of coplanar 3D LSs in two images are related by the same planar homography. Based on these two cues, we efficiently match LSs from two images firstly in pairs through matching the V-junctions formed by adjacent LSs, and secondly in individuals by exploiting local homographies. We extract for each V-junction a scale and affine invariant local region to match V-junctions from two images. The local homographies estimated from V-junction matches are used to match LSs in individuals. To get 3D LSs from the obtained LS matches, we propose to first estimate space planes from clustered LS matches and then back-project image LSs onto the space planes. Markov Random Field (MRF) is introduced to help more reliable LS match clustering. Experiments shows our LS matching algorithm significantly improves the efficiency of state-of-the-art methods while achieves comparable matching performance, and our 3D LS reconstruction algorithm generates more complete and detailed 3D scene models using much fewer images.

  7. Exploitation of other social amoebae by Dictyostelium caveatum.

    PubMed

    Nizak, Clément; Fitzhenry, Robert J; Kessin, Richard H

    2007-02-14

    Dictyostelium amoebae faced with starvation trigger a developmental program during which many cells aggregate and form fruiting bodies that consist of a ball of spores held aloft by a thin stalk. This developmental strategy is open to several forms of exploitation, including the remarkable case of Dictyostelium caveatum, which, even when it constitutes 1/10(3) of the cells in an aggregate, can inhibit the development of the host and eventually devour it. We show that it accomplishes this feat by inhibiting a region of cells, called the tip, which organizes the development of the aggregate into a fruiting body. We use live-cell microscopy to define the D. caveatum developmental cycle and to show that D. caveatum amoebae have the capacity to ingest amoebae of other Dictyostelid species, but do not attack each other. The block in development induced by D. caveatum does not affect the expression of specific markers of prespore cell or prestalk cell differentiation, but does stop the coordinated cell movement leading to tip formation. The inhibition mechanism involves the constitutive secretion of a small molecule by D. caveatum and is reversible. Four Dictyostelid species were inhibited in their development, while D. caveatum is not inhibited by its own compound(s). D. caveatum has evolved a predation strategy to exploit other members of its genus, including mechanisms of developmental inhibition and specific phagocytosis.

  8. Efficient codebook search for vector quantization: exploiting inherent codebook structure

    NASA Astrophysics Data System (ADS)

    Qasem, Mohamed; Du, Xun; Ahalt, Stanley C.

    1999-07-01

    A major problem associated with vector quantization is the complexity of exhaustive codebook search. This problem has hindered the use of this powerful technique for lossy image compression. An exhaustive codebook search requires that an input vector be compared against each code vector in the codebook in order to find the code vector that yields the minimum distortion. Because an exhaustive search does not capitalize on any underlying structure of the code vectors in hyperspace, other researchers have proposed technique that exploit codebook structure, but these technique typically result in sub-optimal distortion. We propose a new method that exploits the nearest neighbor structure of code vectors and significantly reduces the number of computations required in the search process. However, this technique does not introduce additional distortion, and is thus optimal. Our method requires a one time precomputation and a small increase in the memory required to store the codebook. In the best case, arising when the code vectors are largely dispersed in the hyperspace, our method requires only partial search of the codewords. In the worst case, our method requires a full search of the codebook. Since the method depends on the structure of the code vectors in the hyperspace, it is difficult to determine its efficiency in all cases, but test on typical image compression tasks have shown that this method offers on average an 81.16 percent reduction in the total number of multiples, additions and subtractions required as compared to full search.

  9. OFDM Radar Space-Time Adaptive Processing by Exploiting Spatio-Temporal Sparsity

    SciTech Connect

    Sen, Satyabrata

    2013-01-01

    We propose a sparsity-based space-time adaptive processing (STAP) algorithm to detect a slowly-moving target using an orthogonal frequency division multiplexing (OFDM) radar. We observe that the target and interference spectra are inherently sparse in the spatio-temporal domain. Hence, we exploit that sparsity to develop an efficient STAP technique that utilizes considerably lesser number of secondary data and produces an equivalent performance as the other existing STAP techniques. In addition, the use of an OFDM signal increases the frequency diversity of our system, as different scattering centers of a target resonate at different frequencies, and thus improves the target detectability. First, we formulate a realistic sparse-measurement model for an OFDM radar considering both the clutter and jammer as the interfering sources. Then, we apply a residual sparse-recovery technique based on the LASSO estimator to estimate the target and interference covariance matrices, and subsequently compute the optimal STAP-filter weights. Our numerical results demonstrate a comparative performance analysis of the proposed sparse-STAP algorithm with four other existing STAP methods. Furthermore, we discover that the OFDM-STAP filter-weights are adaptable to the frequency-variabilities of the target and interference responses, in addition to the spatio-temporal variabilities. Hence, by better utilizing the frequency variabilities, we propose an adaptive OFDM-waveform design technique, and consequently gain a significant amount of STAP-performance improvement.

  10. Exploiting Fast Exciton Diffusion in Dye-Doped Polymer Nanoparticles to Engineer Efficient Photoswitching.

    PubMed

    Trofymchuk, Kateryna; Prodi, Luca; Reisch, Andreas; Mély, Yves; Altenhöner, Kai; Mattay, Jochen; Klymchenko, Andrey S

    2015-06-18

    Photoswitching of bright fluorescent nanoparticles opens new possibilities for bioimaging with superior temporal and spatial resolution. However, efficient photoswitching of nanoparticles is hard to achieve using Förster resonance energy transfer (FRET) to a photochromic dye, because the particle size is usually larger than the Förster radius. Here, we propose to exploit the exciton diffusion within the FRET donor dyes to boost photoswitching efficiency in dye-doped polymer nanoparticles. To this end, we utilized bulky hydrophobic counterions that prevent self-quenching and favor communication of octadecyl rhodamine B dyes inside a polymer matrix of poly(D,L-lactide-co-glycolide). Among tested counterions, only perfluorinated tetraphenylborate that favors the exciton diffusion enables high photoswitching efficiency (on/off ratio ∼20). The switching improves with donor dye loading and requires only 0.1-0.3 wt % of a diphenylethene photochromic dye. Our nanoparticles were validated both in solution and at the single-particle level. The proposed concept paves the way to new efficient photoswitchable nanomaterials.

  11. Hyperbolic resonances of metasurface cavities.

    PubMed

    Keene, D; Durach, M

    2015-07-13

    We propose a new class of optical resonator structures featuring one or two metasurface reflectors or metacavities and predict that such resonators support novel hyperbolic resonances. As an example of such resonances we introduce hyperbolic Tamm plasmons (HTPs) and hyperbolic Fabry-Perot resonances (HFPs). The hyperbolic optical modes feature low-loss incident power re-distribution over TM and TE polarization output channels, clover-leaf anisotropic dispersion, and other unique properties which are tunable and are useful for multiple applications.

  12. MACHINERY RESONANCE AND DRILLING

    SciTech Connect

    Leishear, R.; Fowley, M.

    2010-01-23

    New developments in vibration analysis better explain machinery resonance, through an example of drill bit chattering during machining of rusted steel. The vibration of an operating drill motor was measured, the natural frequency of an attached spring was measured, and the two frequencies were compared to show that the system was resonant. For resonance to occur, one of the natural frequencies of a structural component must be excited by a cyclic force of the same frequency. In this case, the frequency of drill bit chattering due to motor rotation equaled the spring frequency (cycles per second), and the system was unstable. A soft rust coating on the steel to be drilled permitted chattering to start at the drill bit tip, and the bit oscillated on and off of the surface, which increased the wear rate of the drill bit. This resonant condition is typically referred to as a motor critical speed. The analysis presented here quantifies the vibration associated with this particular critical speed problem, using novel techniques to describe resonance.

  13. Resonant ultrasound spectrometer

    DOEpatents

    Migliori, Albert; Visscher, William M.; Fisk, Zachary

    1990-01-01

    An ultrasound resonant spectrometer determines the resonant frequency spectrum of a rectangular parallelepiped sample of a high dissipation material over an expected resonant response frequency range. A sample holder structure grips corners of the sample between piezoelectric drive and receive transducers. Each transducer is mounted on a membrane for only weakly coupling the transducer to the holder structure and operatively contacts a material effective to remove system resonant responses at the transducer from the expected response range. i.e., either a material such as diamond to move the response frequencies above the range or a damping powder to preclude response within the range. A square-law detector amplifier receives the response signal and retransmits the signal on an isolated shield of connecting cabling to remove cabling capacitive effects. The amplifier also provides a substantially frequency independently voltage divider with the receive transducer. The spectrometer is extremely sensitive to enable low amplitude resonance to be detected for use in calculating the elastic constants of the high dissipation sample.

  14. A NOTE ON THE COMMERCIALLY EXPLOITED MEDICINAL PLNTS OF THE VELLIANGIRI HILLS, COIMBATORE DISTRICT, TAMILNADU

    PubMed Central

    Balasubramaniam, V.; Murugesan, M.

    2004-01-01

    Velliangiri hills is inhabited by many indigenous people mostly depending on ethnobotanical resources. Totally 41 species are found to be commercially exploited for medicines by these peoples. The pressure of commercial exploitation is seriously endangering many species. PMID:22557126

  15. Magnetostrictive resonance excitation

    DOEpatents

    Schwarz, Ricardo B.; Kuokkala, Veli-Tapani

    1992-01-01

    The resonance frequency spectrum of a magnetostrictive sample is remotely determined by exciting the magnetostrictive property with an oscillating magnetic field. The permeability of a magnetostrictive material and concomitant coupling with a detection coil varies with the strain in the material whereby resonance responses of the sample can be readily detected. A suitable sample may be a magnetostrictive material or some other material having at least one side coated with a magnetostrictive material. When the sample is a suitable shape, i.e., a cube, rectangular parallelepiped, solid sphere or spherical shell, the elastic moduli or the material can be analytically determined from the measured resonance frequency spectrum. No mechanical transducers are required and the sample excitation is obtained without contact with the sample, leading to highly reproducible results and a measurement capability over a wide temperature range, e.g. from liquid nitrogen temperature to the Curie temperature of the magnetostrictive material.

  16. Fundamental properties of resonances.

    PubMed

    Ceci, S; Hadžimehmedović, M; Osmanović, H; Percan, A; Zauner, B

    2017-03-27

    All resonances, from hydrogen nuclei excited by the high-energy gamma rays in deep space to newly discovered particles produced in Large Hadron Collider, should be described by the same fundamental physical quantities. However, two distinct sets of properties are used to describe resonances: the pole parameters (complex pole position and residue) and the Breit-Wigner parameters (mass, width, and branching fractions). There is an ongoing decades-old debate on which one of them should be abandoned. In this study of nucleon resonances appearing in the elastic pion-nucleon scattering we discover an intricate interplay of the parameters from both sets, and realize that neither set is completely independent or fundamental on its own.

  17. Nanowire Plasmon Resonators

    NASA Astrophysics Data System (ADS)

    de Leon, Nathalie; Shields, Brendan; Yu, Chun; Englund, Dirk; Akimov, Alexey; Lukin, Mikhail; Park, Hongkun

    2011-05-01

    Strong interactions between light and matter can be engineered by confining light to a small volume for an extended period of time. Nanoscale plasmonic structures can concentrate lighte well below the diffraction limit, but realization of small mode-volume plasmon cavities remains an outstanding challenge. We propose and demonstrate a new approach for realization of nanoscale plasmon resonators enabling strong light-matter interaction. In our approach, chemically synthesized silver nanowires are surrounded by patterned dielectric to create resonators with mode volumes that are two orders of magnitude below the diffraction limit and quality factors approaching 100. We show that they can be used to enhance spontaneous emission rates of CdSe quantum dots and single diamond nitrogen-vacancy centers by a factor larger than 20 at the cavity resonance.

  18. Spectroscopy of baryon resonances

    NASA Astrophysics Data System (ADS)

    Beck, Reinhard; Thoma, Ulrike

    2017-01-01

    Within project A.1 of the SFB/TR16 "Subnuclear Structure of Matter", a large amount of data on photoproduction reactions has been accumulated at the Bonn Electron Stretcher Accelerator ELSA with the CBELSA/TAPS detector and was analysed in detail. In particular, data have been taken with unpolarized or with linearly or circularly polarized photons and with unpolarized or with longitudinally or transversely polarized protons. Photoproduction off neutrons was studied to determine the helicity amplitudes for the excitation of resonances off neutrons. In a partial wave analysis of the data, new resonances have been found and the properties of new and of known resonances have been determined, including the measurement of partial widths of so far unmeasured decay modes.

  19. Quartz resonator processing system

    DOEpatents

    Peters, Roswell D. M.

    1983-01-01

    Disclosed is a single chamber ultra-high vacuum processing system for the oduction of hermetically sealed quartz resonators wherein electrode metallization and sealing are carried out along with cleaning and bake-out without any air exposure between the processing steps. The system includes a common vacuum chamber in which is located a rotatable wheel-like member which is adapted to move a plurality of individual component sets of a flat pack resonator unit past discretely located processing stations in said chamber whereupon electrode deposition takes place followed by the placement of ceramic covers over a frame containing a resonator element and then to a sealing stage where a pair of hydraulic rams including heating elements effect a metallized bonding of the covers to the frame.

  20. Collider Signal I :. Resonance

    NASA Astrophysics Data System (ADS)

    Tait, Tim M. P.

    2010-08-01

    These TASI lectures were part of the summer school in 2008 and cover the collider signal associated with resonances in models of physics beyond the Standard Model. I begin with a review of the Z boson, one of the best-studied resonances in particle physics, and review how the Breit-Wigner form of the propagator emerges in perturbation theory and discuss the narrow width approximation. I review how the LEP and SLAC experiments could use the kinematics of Z events to learn about fermion couplings to the Z. I then make a brief survey of models of physics beyond the Standard Model which predict resonances, and discuss some of the LHC observables which we can use to discover and identify the nature of the BSM physics. I finish up with a discussion of the linear moose that one can use for an effective theory description of a massive color octet vector particle.

  1. Fundamental properties of resonances

    PubMed Central

    Ceci, S.; Hadžimehmedović, M.; Osmanović, H.; Percan, A.; Zauner, B.

    2017-01-01

    All resonances, from hydrogen nuclei excited by the high-energy gamma rays in deep space to newly discovered particles produced in Large Hadron Collider, should be described by the same fundamental physical quantities. However, two distinct sets of properties are used to describe resonances: the pole parameters (complex pole position and residue) and the Breit-Wigner parameters (mass, width, and branching fractions). There is an ongoing decades-old debate on which one of them should be abandoned. In this study of nucleon resonances appearing in the elastic pion-nucleon scattering we discover an intricate interplay of the parameters from both sets, and realize that neither set is completely independent or fundamental on its own. PMID:28345595

  2. 75 FR 40838 - Establishment of the Advisory Board on Elder Abuse, Neglect, and Exploitation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-14

    ... HUMAN SERVICES Establishment of the Advisory Board on Elder Abuse, Neglect, and Exploitation AGENCY... Board on Elder Abuse, Neglect, and Exploitation is authorized under section 2021, Subtitle H--Elder... establishment of the Advisory Board on Elder Abuse, Neglect, and Exploitation, as directed by section...

  3. Exploitation of Existing Voice Over Internet Protocol Technology for Department of the Navy Application

    DTIC Science & Technology

    2002-09-01

    NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS Approved for public release; distribution is unlimited EXPLOITATION OF EXISTING VOICE...Title (Mix case letters) Exploitation of Existing Voice over Internet Protocol Technology for Department of the Navy Application 6. AUTHOR(S...unlimited EXPLOITATION OF EXISTING VOICE OVER INTERNET PROTOCOL TECHNOLOGY FOR DEPARTMENT OF THE NAVY APPLICATION David T. Wallace Captain

  4. The Illusions and Juxtapositions of Commercial Sexual Exploitation among Youth: Identifying Effective Street-Outreach Strategies

    ERIC Educational Resources Information Center

    Holger-Ambrose, Beth; Langmade, Cheree; Edinburgh, Laurel D.; Saewyc, Elizabeth

    2013-01-01

    To explore sexually exploited youths' perspectives of how street outreach workers can effectively provide outreach and connections to services, we conducted qualitative interviews with 13 female participants, ages 14 to 22, in a Midwest U.S. city. Participants reported multiple types of exploitation, most first exploited by age 13, plus substance…

  5. Field resonance propulsion concept

    NASA Technical Reports Server (NTRS)

    Holt, A. C.

    1979-01-01

    A propulsion concept was developed based on a proposed resonance between coherent, pulsed electromagnetic wave forms, and gravitational wave forms (or space-time metrics). Using this concept a spacecraft propulsion system potentially capable of galactic and intergalactic travel without prohibitive travel times was designed. The propulsion system utilizes recent research associated with magnetic field line merging, hydromagnetic wave effects, free-electron lasers, laser generation of megagauss fields, and special structural and containment metals. The research required to determine potential, field resonance characteristics and to evaluate various aspects of the spacecraft propulsion design is described.

  6. Method for resonant measurement

    DOEpatents

    Rhodes, George W.; Migliori, Albert; Dixon, Raymond D.

    1996-01-01

    A method of measurement of objects to determine object flaws, Poisson's ratio (.sigma.) and shear modulus (.mu.) is shown and described. First, the frequency for expected degenerate responses is determined for one or more input frequencies and then splitting of degenerate resonant modes are observed to identify the presence of flaws in the object. Poisson's ratio and the shear modulus can be determined by identification of resonances dependent only on the shear modulus, and then using that shear modulus to find Poisson's ratio using other modes dependent on both the shear modulus and Poisson's ratio.

  7. Hexagonal quartz resonator

    DOEpatents

    Peters, R.D.M.

    1982-11-02

    A generally flat, relatively thin AT-cut piezoelectric resonator element structured to minimize the force-frequency effect when mounted and energized in a housing. The resonator is in the form of an equilateral hexagon with the X crystallographic axis of the crystal passing through one set of opposing corners with mounting being effected at an adjacent set of corners respectively [+-]60[degree] away from the X axis which thereby results in a substantially zero frequency shift of the operating frequency. 3 figs.

  8. Method for resonant measurement

    DOEpatents

    Rhodes, G.W.; Migliori, A.; Dixon, R.D.

    1996-03-05

    A method of measurement of objects to determine object flaws, Poisson`s ratio ({sigma}) and shear modulus ({mu}) is shown and described. First, the frequency for expected degenerate responses is determined for one or more input frequencies and then splitting of degenerate resonant modes are observed to identify the presence of flaws in the object. Poisson`s ratio and the shear modulus can be determined by identification of resonances dependent only on the shear modulus, and then using that shear modulus to find Poisson`s ratio using other modes dependent on both the shear modulus and Poisson`s ratio. 1 fig.

  9. Physics of Sports: Resonances

    NASA Astrophysics Data System (ADS)

    Browning, David

    2000-04-01

    When force is applied by an athlete to sports equipment resonances can occur. Just a few examples are: the ringing of a spiked volleyball, the strumming of a golf club shaft during a swing, and multiple modes induced in an aluminum baseball bat when striking a ball. Resonances produce acoustic waves which, if conditions are favorable, can be detected off the playing field. This can provide a means to evaluate athletic performance during game conditions. Results are given from the use of a simple hand-held acoustic detector - by a spectator sitting in the stands - to determine how hard volleyballs were spiked during college and high school games.

  10. Waveform design for detection of weapons based on signature exploitation

    NASA Astrophysics Data System (ADS)

    Ahmad, Fauzia; Amin, Moeness G.; Dogaru, Traian

    2010-04-01

    We present waveform design based on signature exploitation techniques for improved detection of weapons in urban sensing applications. A single-antenna monostatic radar system is considered. Under the assumption of exact knowledge of the target orientation and, hence, known impulse response, matched illumination approach is used for optimal target detection. For the case of unknown target orientation, we analyze the target signatures as random processes and perform signal-to-noise-ratio based waveform optimization. Numerical electromagnetic modeling is used to provide the impulse responses of an AK-47 assault rifle for various target aspect angles relative to the radar. Simulation results depict an improvement in the signal-to-noise-ratio at the output of the matched filter receiver for both matched illumination and stochastic waveforms as compared to a chirp waveform of the same duration and energy.

  11. Exploiting CRISPR/Cas: interference mechanisms and applications.

    PubMed

    Richter, Hagen; Randau, Lennart; Plagens, André

    2013-07-12

    The discovery of biological concepts can often provide a framework for the development of novel molecular tools, which can help us to further understand and manipulate life. One recent example is the elucidation of the prokaryotic adaptive immune system, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) that protects bacteria and archaea against viruses or conjugative plasmids. The immunity is based on small RNA molecules that are incorporated into versatile multi-domain proteins or protein complexes and specifically target viral nucleic acids via base complementarity. CRISPR/Cas interference machines are utilized to develop novel genome editing tools for different organisms. Here, we will review the latest progress in the elucidation and application of prokaryotic CRISPR/Cas systems and discuss possible future approaches to exploit the potential of these interference machineries.

  12. Los Azufres geothermal field: Observed response after 12-year exploitation

    SciTech Connect

    Maldonado, G.J.

    1995-12-31

    Exploitation of the Los Azufres Geothermal field was initiated in August 1982, with the electric power generation of five 5-MW wellhead units. Since then another 70 MW have been installed. A large amount of information has been compiled, including geologic, geochemical, production, and reservoir characteristics. The data were evaluated to detect the extent of observable changes in the main reservoir parameters over the twelve-year production period. Pressure and temperature measurements in Los Azufres wells show that geothermal fluid distribution is strongly influenced by the presence of permeable structures. Wellhead production and chemical analysis of the separated brine show that we are dealing with a highly heterogeneous reservoir, were the drawdown and enthalpy changes depend on the position of the well being studied.

  13. Exploiting Ultra Tight-Binding Ligands for Separations Technologies

    SciTech Connect

    Busch, Daryle; Givens, Richard S.; Zuo, Xiaobin; Zhang, Chi; Mosha, Donnati; Lee, Jong0Ill; Bushan, K. Mani; Hassan, Mansour M.; Loving, Galen

    2003-09-10

    The classic slowness that has kept the most powerful ligands from being used in separations applications is under attack in two ways: (1) replacing metal ion - ligand equilibration with switch binding and release as the mode of complexation. By exploiting the tight-binding capabilities of cryptands, the capture of selected metal ions isolates them from their environment. These cryptands are constructed with photoactivatable functions that sever the cryptand, releasing encapsulated metal ions. The precursors have been modified to capture the metal ion concomitant with crytate formation. (2) developing a methodology (the soil poultice) so slow that powerful ligands can be used. A solution containing the specially designed ligand is mixed with a solid macroporous imprinted polymer (MIPs) and applied to the contaminated area. The ligand captures the metal ion and the MIPs captures the resulting complex. Current studies focus on combinations of MIPs-complex interactions to optimize strength of binding and selectivity.

  14. Smart facility application: exploiting space technology for smart city solution

    NASA Astrophysics Data System (ADS)

    Termizi, A. A. A.; Ahmad, N.; Omar, M. F.; Wahap, N. A.; Zainal, D.; Ismail, N. M.

    2016-06-01

    Facilities and amenities management is amongst the core functionalities of local government. Considering the vast area that local government has to manage, a smart solution is extremely inevitable to solve issues such as inefficient maintenance of public parks, drainage system and so forth. Therefore, this paper aims to offer a smart city solution which exploits the benefit of space technology. This proposed solution is one of the modules developed in Spatial Smart City Service Delivery Engine (SSC SDE) Project undertaken by Agensi Angkasa Negara (ANGKASA). Various levels of local government have been chosen to understand real issues faced by them. Based on this data, a Smart Facility application has been developed with the aim to enhance the service delivery by the local government hence improving citizens’ satisfaction. Since this project is still in progress, this paper will merely discussing the concept of this application.

  15. Protocol to Exploit Waiting Resources for UASNs †

    PubMed Central

    Hung, Li-Ling; Luo, Yung-Jeng

    2016-01-01

    The transmission speed of acoustic waves in water is much slower than that of radio waves in terrestrial wireless sensor networks. Thus, the propagation delay in underwater acoustic sensor networks (UASN) is much greater. Longer propagation delay leads to complicated communication and collision problems. To solve collision problems, some studies have proposed waiting mechanisms; however, long waiting mechanisms result in low bandwidth utilization. To improve throughput, this study proposes a slotted medium access control protocol to enhance bandwidth utilization in UASNs. The proposed mechanism increases communication by exploiting temporal and spatial resources that are typically idle in order to protect communication against interference. By reducing wait time, network performance and energy consumption can be improved. A performance evaluation demonstrates that when the data packets are large or sensor deployment is dense, the energy consumption of proposed protocol is less than that of existing protocols as well as the throughput is higher than that of existing protocols. PMID:27005624

  16. Commercial Sexual Exploitation of Children and State Child Welfare Systems.

    PubMed

    Bounds, Dawn; Julion, Wrenetha A; Delaney, Kathleen R

    2015-01-01

    In several states, commercial sexual exploitation of children (CSEC) is now a reportable child abuse offense. Illinois has taken the lead in tackling the issue and the Illinois experience illuminates valuable lessons. This article delineates the protection, practice, and policy implications that evolve when CSEC falls under a state child welfare system. The specific aims are to (a) discuss CSEC, its victims, risks, harms, and challenges inherent in providing effective care; (b) use Illinois as an exemplar to explicate the consequences and implementation challenges of establishing a state reporting system that frames CSEC as a child welfare issue; (c) recommend strategies for developing effective state reporting models, and (d) demonstrate how nurses are well poised to advocate for victims of human trafficking on both state and national levels. Recommendations for improving the identification of CSEC victims and overcoming challenges to state implementation are offered.

  17. Exploitation of genus Rhodosporidium for microbial lipid production.

    PubMed

    Xu, Jingyang; Liu, Dehua

    2017-03-01

    Oleaginous microorganisms are receiving significant attention worldwide for their utility in biodiesel production and the potentiality to produce some specialty-type lipids. There is an increasing interest in isolation/adaption of robust microbe strains and design of innovative fermentation processes to make microbial lipid production a more efficient and economically feasible bio-process. Currently, the genus Rhodosporidium has been considered an important candidate, for the reason that several strains belonging to this genus have shown excellent capabilities of lipid accumulation, broad adaptabilities to various substrates, and co-production of some carotenoids. This paper reviews the current trends in the exploitation of Rhodosporidium species for microbial lipid production, including the utilization of various (single or mixed, pure or waste-derived) substrates, progress of genetic modification and metabolic engineering, innovations in fermentation mode, lipid characterizations and their potential applications. Finally, the constraints and perspectives of cultivating Rhodosporidium species for lipid production are also discussed.

  18. SMARTS: Exploiting Temporal Locality and Parallelism through Vertical Execution

    SciTech Connect

    Beckman, P.; Crotinger, J.; Karmesin, S.; Malony, A.; Oldehoeft, R.; Shende, S.; Smith, S.; Vajracharya, S.

    1999-01-04

    In the solution of large-scale numerical prob- lems, parallel computing is becoming simultaneously more important and more difficult. The complex organization of today's multiprocessors with several memory hierarchies has forced the scientific programmer to make a choice between simple but unscalable code and scalable but extremely com- plex code that does not port to other architectures. This paper describes how the SMARTS runtime system and the POOMA C++ class library for high-performance scientific computing work together to exploit data parallelism in scientific applications while hiding the details of manag- ing parallelism and data locality from the user. We present innovative algorithms, based on the macro -dataflow model, for detecting data parallelism and efficiently executing data- parallel statements on shared-memory multiprocessors. We also desclibe how these algorithms can be implemented on clusters of SMPS.

  19. Exploiting Receptor Competition to Enhance Nanoparticle Binding Selectivity

    NASA Astrophysics Data System (ADS)

    Angioletti-Uberti, Stefano

    2017-02-01

    Nanoparticles functionalized with multiple ligands can be programed to bind biological targets depending on the receptors they express, providing a general mechanism exploited in various technologies, from selective drug delivery to biosensing. For binding to be highly selective, ligands should exclusively interact with specific targeted receptors, because the formation of bonds with other, untargeted ones would lead to nonspecific binding and potentially harmful behavior. This poses a particular problem for multivalent nanoparticles, because even very weak bonds can collectively lead to strong binding. A statistical mechanical model is used here to describe how competition between different receptors together with multivalent effects can be harnessed to design ligand-functionalized nanoparticles insensitive to the presence of untargeted receptors, preventing nonspecific binding.

  20. Tricking the guard: Exploiting Plant Defense for Disease Susceptibility

    PubMed Central

    Lorang, J.; Kidarsa, T.; Bradford, C. S.; Gilbert, B.; Curtis, M.; Tzeng, S-C.; Maier, C.S.; Wolpert, T. J.

    2014-01-01

    Typically pathogens deploy virulence effectors to disable defense. Plants defeat effectors with resistance proteins that guard effector targets. Here we show that a pathogen exploits a resistance protein by activating it to confer susceptibility. Interactions of victorin, an effector produced by the necrotrophic fungus Cochliobolus victoriae, TRX-h5, a defense-associated thioredoxin, and LOV1, an Arabidopsis susceptibility protein, recapitulate the guard mechanism of plant defense. In LOV1’s absence, victorin inhibits TRX-h5 resulting in compromised defense but not disease by C. victoriae. In LOV1’s presence, victorin binding to TRX-h5 activates LOV1 and elicits a resistance-like response that confers disease susceptibility. We propose victorin is or mimics a conventional pathogen virulence effector that was defeated by LOV1 and confers virulence to C. victoriae solely because it incites defense. PMID:23087001

  1. Exploiting multicore compute resources in the CMS experiment

    NASA Astrophysics Data System (ADS)

    Ramírez, J. E.; Pérez-Calero Yzquierdo, A.; Hernández, J. M.; CMS Collaboration

    2016-10-01

    CMS has developed a strategy to efficiently exploit the multicore architecture of the compute resources accessible to the experiment. A coherent use of the multiple cores available in a compute node yields substantial gains in terms of resource utilization. The implemented approach makes use of the multithreading support of the event processing framework and the multicore scheduling capabilities of the resource provisioning system. Multicore slots are acquired and provisioned by means of multicore pilot agents which internally schedule and execute single and multicore payloads. Multicore scheduling and multithreaded processing are currently used in production for online event selection and prompt data reconstruction. More workflows are being adapted to run in multicore mode. This paper presents a review of the experience gained in the deployment and operation of the multicore scheduling and processing system, the current status and future plans.

  2. Exploiting open data: a new era in pharmacoinformatics.

    PubMed

    Goldmann, Daria; Montanari, Floriane; Richter, Lars; Zdrazil, Barbara; Ecker, Gerhard F

    2014-04-01

    Within the last decade open data concepts has been gaining increasing interest in the area of drug discovery. With the launch of ChEMBL and PubChem, an enormous amount of bioactivity data was made easily accessible to the public domain. In addition, platforms that semantically integrate those data, such as the Open PHACTS Discovery Platform, permit querying across different domains of open life science data beyond the concept of ligand-target-pharmacology. However, most public databases are compiled from literature sources and are thus heterogeneous in their coverage. In addition, assay descriptions are not uniform and most often lack relevant information in the primary literature and, consequently, in databases. This raises the question how useful large public data sources are for deriving computational models. In this perspective, we highlight selected open-source initiatives and outline the possibilities and also the limitations when exploiting this huge amount of bioactivity data.

  3. Exploiting the colloidal nanocrystal library to construct electronic devices

    NASA Astrophysics Data System (ADS)

    Choi, Ji-Hyuk; Wang, Han; Oh, Soong Ju; Paik, Taejong; Sung, Pil; Sung, Jinwoo; Ye, Xingchen; Zhao, Tianshuo; Diroll, Benjamin T.; Murray, Christopher B.; Kagan, Cherie R.

    2016-04-01

    Synthetic methods produce libraries of colloidal nanocrystals with tunable physical properties by tailoring the nanocrystal size, shape, and composition. Here, we exploit colloidal nanocrystal diversity and design the materials, interfaces, and processes to construct all-nanocrystal electronic devices using solution-based processes. Metallic silver and semiconducting cadmium selenide nanocrystals are deposited to form high-conductivity and high-mobility thin-film electrodes and channel layers of field-effect transistors. Insulating aluminum oxide nanocrystals are assembled layer by layer with polyelectrolytes to form high-dielectric constant gate insulator layers for low-voltage device operation. Metallic indium nanocrystals are codispersed with silver nanocrystals to integrate an indium supply in the deposited electrodes that serves to passivate and dope the cadmium selenide nanocrystal channel layer. We fabricate all-nanocrystal field-effect transistors on flexible plastics with electron mobilities of 21.7 square centimeters per volt-second.

  4. Review of oil and gas exploitation impacts on grizzly bears

    SciTech Connect

    Schallenberger, A.

    1980-01-01

    It is concluded that available information indicates that impacts of oil and gas exploitation should be considered primarily detrimental for grizzly bears in northwestern Montana. Research has shown that grizzlies tend to react strongly to aircraft, especially helicopters. Marked animals previously captured by aircraft show the greatest reaction. Helicopter disturbance may cause den abandonment. Biologists suggest that road development has contributed to a decline in numbers of bears by accelerating habitat loss and increasing hunting and poaching pressure. Use of river valleys for transportation corridors, campsites, and other activities magnifies the effect of human presence by concentrating it in some of the most vulnerable and essential grizzly habitat. Bear-human conflicts may increase as a result of secondary development such as recreation, logging, livestock grazing, and construction of subdivisions.

  5. Exploiting hypoxia in solid tumors to achieve oncolysis.

    PubMed

    Payne, Anthony G

    2007-01-01

    Chemo- and radio-resistant cancer cells within solid tumors undermine the effectiveness of these approaches to achieving oncolysis. These resistant cells and clusters of cells typically thrive at low oxygen tensions and are reliant on anaerobic metabolic pathways that churn out lactate. This hypoxic state is one that can be exploited and in this paper a novel method is advanced involving tumor cell infiltration by bifidobacterium species which should bring about prodigious lactate synthesis; concomitant blocking of its enzymatic degradation by urea as well as export (from the cell) by use of quercetin; depletion of ATP using exogenous thyroid; and compromised oxidative catabolism of free fatty acids and amino acids via oral intake of l-hydroxycitrate, melatonin and nontoxic NDGA. This "anaerobic pathway cocktail", it is hypothesized, will bring about a profound reduction in intracellular pH and a compromised state of cellular energetics sufficient to effect oncolysis.

  6. Exploiting Intimate Relationships: Controlling Mosquito-Transmitted Disease with Wolbachia.

    PubMed

    Caragata, Eric P; Dutra, Heverton L C; Moreira, Luciano A

    2016-03-01

    Mosquito-transmitted diseases impose a growing burden on human health, and current control strategies have proven insufficient to stem the tide. The bacterium Wolbachia is a novel and promising form of control for mosquito-transmitted disease. It manipulates host biology, restricts infection with dengue and other pathogens, and alters host reproduction to promote rapid spread in the field. In this review, we examine how the intimate and diverse relationships formed between Wolbachia and their mosquito hosts can be exploited for disease control purposes. We consider these relationships in the context of recent developments, including successful field trials with Wolbachia-infected mosquitoes to combat dengue, and new Wolbachia infections in key malaria vectors, which have enhanced the disease control prospects of this unique bacterium.

  7. Microbial biosurfactants: challenges and opportunities for future exploitation.

    PubMed

    Marchant, Roger; Banat, Ibrahim M

    2012-11-01

    The drive for industrial sustainability has pushed biosurfactants to the top of the agenda of many companies. Biosurfactants offer the possibility of replacing chemical surfactants, produced from nonrenewable resources, with alternatives produced from cheap renewable feedstocks. Biosurfactants are also attractive because they are less damaging to the environment yet are robust enough for industrial use. The most promising biosurfactants at the present time are the glycolipids, sophorolipids produced by Candida yeasts, mannosylerythritol lipids (MELs) produced by Pseudozyma yeasts, and rhamnolipids produced by Pseudomonas. Despite the current enthusiasm for these compounds several residual problems remain. This review highlights remaining problems and indicates the prospects for imminent commercial exploitation of a new generation of microbial biosurfactants.

  8. Microfluidic photocatalytic device exploiting PDMS/TiO2 nanocomposite

    NASA Astrophysics Data System (ADS)

    Lamberti, Andrea

    2015-04-01

    A microfluidic device exploiting PDMS/TiO2 nanocomposite has been used for photocatalytic degradation studies of organic dye. By using commercial P25 TiO2 nanoparticles (NPs) and conventional PDMS casting and replication techniques, high density and well-dispersed TiO2 NPs were embedded in the elastomeric surface. The obtained nanocomposite membranes were characterized by morphological, chemical, and physical points of view. The fabrication process allows an easy integration of the membrane into an all-PDMS microfluidic device for pollutant photodegradation. The high surface-to-volume ratio intrinsic in nanoparticles and the functional properties of the proposed nanocomposite substrate are responsible for the interesting photocatalytic device performance.

  9. Exploiting existing software in libraries : successes, failures, and reasons why.

    SciTech Connect

    Gropp, W.

    1999-01-13

    The PETSc (Portable Extensible Tools for Scientific computing) library arose from research into domain decomposition methods which require combining many different solutions in a single application. The initial efforts tried to use existing numerical software but had limited success. The problems include everything from faulty assumptions about the computing environment (e.g., how many processes there are) to implicit (yet deadly) global state. More recently, PETSC and PVODE have found a way to cooperate, and new techniques that exploit dynamically linked libraries offer a more general approach to interoperable components. The paper highlights some of the issues in building sharable component software and discussing mistakes still often made in designing, maintaining, documenting, and testing components.

  10. Calibration and exploitation of a narrowband imaging polarimeter

    NASA Astrophysics Data System (ADS)

    Duggin, Michael J.; Loe, Richard S.

    2002-05-01

    The integration and calibration of a narrow-band imaging polarimeter is described. The system is designed to exploit subtle spectral details in visible and near-IR polarimetric images. All of the system components were commercial off the shelf. This device uses a tunable liquid crystal filter and a 16-bit cooled CCD camera. The challenges of calibrating a narrow-band imaging polarimeter are discussed. We describe examples of image data collected in the laboratory, which show that spectral polarimetric data is superior to unpolarized intensity data in facilitating the extraction of detail in shadowed regions below a vegetative canopy. In particular, we introduce a polarization-based normalized difference vegetation index (NDVI) algorithm that demonstrates significant contrast enhancement between a man-made object and a foilage background.

  11. Image exploitation using multi-sensor/neural network systems

    SciTech Connect

    Uberbacher, E.C.; Xu, Y.; Lee, R.W.

    1995-12-31

    We have developed and evaluated a tool for change detection and other analysis tasks relevant to image exploitation. The tool, visGRAIL, integrates three key elements: (1) the use of multiple algorithms to extract information from images - feature extractors or {open_quotes}sensors{close_quotes}, (2) an algorithm to fuse the information - presently a neural network, and (3) empirical estimation of the fusion parameters based on a representative set of images. The system was applied to test images in the RADIUS Common Development Environment (RCDE). In a task designed to distinguish natural scenes from those containing various amounts of human-made objects and structure, the system classified correctly 95% of 350 images in a test set. This paper describes details of the feature extractors, and presents analyses of the discriminatory characteristics of the features. visGRAIL has been integrated into the RCDE.

  12. How Polyomaviruses Exploit the ERAD Machinery to Cause Infection

    PubMed Central

    Dupzyk, Allison; Tsai, Billy

    2016-01-01

    To infect cells, polyomavirus (PyV) traffics from the cell surface to the endoplasmic reticulum (ER) where it hijacks elements of the ER-associated degradation (ERAD) machinery to penetrate the ER membrane and reach the cytosol. From the cytosol, the virus transports to the nucleus, enabling transcription and replication of the viral genome that leads to lytic infection or cellular transformation. How PyV exploits the ERAD machinery to cross the ER membrane and access the cytosol, a decisive infection step, remains enigmatic. However, recent studies have slowly unraveled many aspects of this process. These emerging insights should advance our efforts to develop more effective therapies against PyV-induced human diseases. PMID:27589785

  13. Exploiting the genetic potential of polyketide producing streptomycetes.

    PubMed

    Weber, T; Welzel, K; Pelzer, S; Vente, A; Wohlleben, W

    2003-12-19

    Streptomycetes are the most important bacterial producers of bioactive secondary metabolites such as antibiotics or cytostatics. Due to the emerging resistance of pathogenic bacteria to all commonly used antibiotics, new and modified natural compounds are required for the development of novel drugs. In addition to the classical screening for natural compounds, genome driven approaches like combinatorial biosynthesis are permanently gaining relevance for the generation of new structures. This technology utilizes the combination of genes from different biosynthesis pathways resulting in the production of novel or modified metabolites. The basis for this strategy is the access to a significant number of genes and the knowledge about the activity and specificity of the enzymes encoded by them. A joint initiative was started to exploit the biosynthesis gene clusters from streptomycetes. In this publication, an overview of the strategy for the identification and characterization of numerous biosynthesis gene clusters for polyketides displaying interesting functions and particular structural features is given.

  14. Exploiting periodicity to extract the atrial activity in atrial arrhythmias

    NASA Astrophysics Data System (ADS)

    Llinares, Raul; Igual, Jorge

    2011-12-01

    Atrial fibrillation disorders are one of the main arrhythmias of the elderly. The atrial and ventricular activities are decoupled during an atrial fibrillation episode, and very rapid and irregular waves replace the usual atrial P-wave in a normal sinus rhythm electrocardiogram (ECG). The estimation of these wavelets is a must for clinical analysis. We propose a new approach to this problem focused on the quasiperiodicity of these wavelets. Atrial activity is characterized by a main atrial rhythm in the interval 3-12 Hz. It enables us to establish the problem as the separation of the original sources from the instantaneous linear combination of them recorded in the ECG or the extraction of only the atrial component exploiting the quasiperiodic feature of the atrial signal. This methodology implies the previous estimation of such main atrial period. We present two algorithms that separate and extract the atrial rhythm starting from a prior estimation of the main atrial frequency. The first one is an algebraic method based on the maximization of a cost function that measures the periodicity. The other one is an adaptive algorithm that exploits the decorrelation of the atrial and other signals diagonalizing the correlation matrices at multiple lags of the period of atrial activity. The algorithms are applied successfully to synthetic and real data. In simulated ECGs, the average correlation index obtained was 0.811 and 0.847, respectively. In real ECGs, the accuracy of the results was validated using spectral and temporal parameters. The average peak frequency and spectral concentration obtained were 5.550 and 5.554 Hz and 56.3 and 54.4%, respectively, and the kurtosis was 0.266 and 0.695. For validation purposes, we compared the proposed algorithms with established methods, obtaining better results for simulated and real registers.

  15. South African Astronomy in the Internet Era: exploiting the AVO

    NASA Astrophysics Data System (ADS)

    Charles, Phil

    2007-04-01

    The combination of SALT, the bid to host SKA and the association with HESS have propelled South Africa into a world-class position with regard to multi-wavelength observational facilities, indicating the scale of their hopes and aspirations post-1994. All of these facilities exploit the geographical advantage that South Africa possesses, combined with substantial international collaborations to share the financial burden, whilst benefitting the infrastructure and development of South African science and industry. However, the effective use of SALT (and which is far more critical for KAT, an SKA technology demonstrator) requires dramatic improvements in both the local and international Internet bandwidth, which lags far behind First World norms (in terms of both the data rates available and their cost). Such connectivity is essential for raw data transfer from telescope to data centre, and then subsequent access by (national and international) users of the processed data. Current capabilities are stretched to the limit by SALT operations alone (which are measured in terms of Gb/night), but completely different solutions will be needed for KAT and SKA (which require Gb/s). Potential solutions for both South African and international users of SALT are being developed which exploit the Astrophysical Virtual Observatory (AVO) and Grid concepts and the substantial international investment that is currently ongoing. A collaboration with the UK's AstroGRID is acting as a testbed in which the raw data archive will remain in Cape Town at SAAO, but AstroGRID will act as a front end for setting up data pipelining procedures from which only mostly reduced data need be transferred to the end user. Comparisons with other remote international facilities (e.g the observatories in La Palma, Spain) plus the infrastructure required for KAT will be presented and discussed.

  16. GOCE and Future Gravity Missions for Geothermal Energy Exploitation

    NASA Astrophysics Data System (ADS)

    Pastorutti, Alberto; Braitenberg, Carla; Pivetta, Tommaso; Mariani, Patrizia

    2016-08-01

    Geothermal energy is a valuable renewable energy source the exploitation of which contributes to the worldwide reduction of consumption of fossil fuels oil and gas. The exploitation of geothermal energy is facilitated where the thermal gradient is higher than average leading to increased surface heat flow. Apart from the hydrologic circulation properties which depend on rock fractures and are important due to the heat transportation from the hotter layers to the surface, essential properties that increase the thermal gradient are crustal thinning and radiogenic heat producing rocks. Crustal thickness and rock composition form the link to the exploration with the satellite derived gravity field, because both induce subsurface mass changes that generate observable gravity anomalies. The recognition of gravity as a useful investigation tool for geothermal energy lead to a cooperation with ESA and the International Renewable Energy Agency (IRENA) that included the GOCE derived gravity field in the online geothermal energy investigation tool of the IRENA database. The relation between the gravity field products as the free air gravity anomaly, the Bouguer and isostatic anomalies and the heat flow values is though not straightforward and has not a unique relationship. It is complicated by the fact that it depends on the geodynamical context, on the geologic context and the age of the crustal rocks. Globally the geological context and geodynamical history of an area is known close to everywhere, so that a specific known relationship between gravity and geothermal potential can be applied. In this study we show the results of a systematic analysis of the problem, including some simulations of the key factors. The study relies on the data of GOCE and the resolution and accuracy of this satellite. We also give conclusions on the improved exploration power of a gravity mission with higher spatial resolution and reduced data error, as could be achieved in principle by flying

  17. Exploiting tumor shrinkage through temporal optimization of radiotherapy

    NASA Astrophysics Data System (ADS)

    Unkelbach, Jan; Craft, David; Hong, Theodore; Papp, Dávid; Ramakrishnan, Jagdish; Salari, Ehsan; Wolfgang, John; Bortfeld, Thomas

    2014-06-01

    In multi-stage radiotherapy, a patient is treated in several stages separated by weeks or months. This regimen has been motivated mostly by radiobiological considerations, but also provides an approach to reduce normal tissue dose by exploiting tumor shrinkage. The paper considers the optimal design of multi-stage treatments, motivated by the clinical management of large liver tumors for which normal liver dose constraints prohibit the administration of an ablative radiation dose in a single treatment. We introduce a dynamic tumor model that incorporates three factors: radiation induced cell kill, tumor shrinkage, and tumor cell repopulation. The design of multi-stage radiotherapy is formulated as a mathematical optimization problem in which the total dose to the normal tissue is minimized, subject to delivering the prescribed dose to the tumor. Based on the model, we gain insight into the optimal administration of radiation over time, i.e. the optimal treatment gaps and dose levels. We analyze treatments consisting of two stages in detail. The analysis confirms the intuition that the second stage should be delivered just before the tumor size reaches a minimum and repopulation overcompensates shrinking. Furthermore, it was found that, for a large range of model parameters, approximately one-third of the dose should be delivered in the first stage. The projected benefit of multi-stage treatments in terms of normal tissue sparing depends on model assumptions. However, the model predicts large dose reductions by more than a factor of 2 for plausible model parameters. The analysis of the tumor model suggests that substantial reduction in normal tissue dose can be achieved by exploiting tumor shrinkage via an optimal design of multi-stage treatments. This suggests taking a fresh look at multi-stage radiotherapy for selected disease sites where substantial tumor regression translates into reduced target volumes.

  18. Enhancing space data exploitation through advanced data routing protocols

    NASA Astrophysics Data System (ADS)

    Daglis, I. A.; Rontogiannis, A.; Anastasiadis, A.; Sykioti, O.; Balasis, G.; Keramitsoglou, I.; Paronis, D.; Tsaoussidis, V.; Diamantopoulos, S.

    2012-01-01

    Data sharing and access are major issues in space sciences, as they influence the degree of data exploitation. The project "Space-Data Routers", which was initiated recently, has the aim of allowing space agencies, academic institutes and research centres to share space-data generated by single or multiple missions, in an efficient, secure and automated manner. The approach of "Space-Data Routers" relies on space internetworking - and in particular on Delay-Tolerant Networking (DTN), which marks the new era in space communications, unifies space and earth communication infrastructures and delivers a set of tools and protocols for space-data exploitation. The project has started with defining limitations currently imposed by typical space mission scenarios, in which the National Observatory of Athens (NOA) is currently involved, including space exploration, planetary exploration and Earth observation missions. Here we are presenting the mission scenarios and the associated major scientific objectives of "Space-Data Routers", with an emphasis on the Sun-Earth connection and the Mars hyperspectral imaging spectroscopy scenarios. In the case of the Sun-Earth connection scenario, we plan to test and validate the capabilities of Space-Data Routers in providing: a) Simultaneous real- time sampling of space plasmas from multiple points with cost-effective means and measuring of phenomena with higher resolution and better coverage to address outstanding science questions and b) Successful data transmission even in hostile communication conditions. In the case of the Mars hyperspectral imaging spectroscopy scenario we plan to test and validate the capabilities of Space-Data Routers in augmenting the data volume received from Mars Express, through the increase of Mars Express connectivity with ground stations and through the increase of access speed to the hyperspectral data depository.

  19. Topological lasing in resonant photonic structures

    NASA Astrophysics Data System (ADS)

    Pilozzi, Laura; Conti, Claudio

    2016-05-01

    We exploit topological edge states in resonant photonic crystals to attain strongly localized resonances and demonstrate lasing in these modes upon optical excitation. The use of virtually lossless topologically isolated edge states may lead to a class of thresholdless lasers operating without inversion. One needs, however, to understand whether topological states may be coupled to external radiation and act as active cavities. We study a two-level topological insulator and show that self-induced transparency pulses can directly excite edge states. We simulate laser emission by a suitably designed topological cavity and show that it can emit tunable radiation. For a configuration of sites following the off-diagonal Aubry-André-Harper model, we solve the Maxwell-Bloch equations in the time domain and provide a first-principles confirmation of topological lasers. Our results open the road to a class of light emitters with topological protection for applications ranging from low-cost energetically effective integrated laser sources, also including silicon photonics, to strong-coupling devices for studying ultrafast quantum processes with engineered vacuum.

  20. Probing Students' Understanding of Resonance

    NASA Astrophysics Data System (ADS)

    Murphy, Sytil; McBride, Dyan; Gross, Josh; Zollman, Dean

    2009-11-01

    Resonant phenomena play a crucial role in magnetic resonance imaging (MRI), a widely used medical tool in today's society. The basic features of the resonance in MRI can be taught by looking at the resonance of a compass driven by an electromagnetic field. However, resonance in a oscillating magnetic field is not a phenomenon that is familiar to most students. Thus, as a precursor to creating instructional materials, we investigated how students applied their learning about resonance as traditionally taught to this novel system.

  1. RESONATOR PARTICLE SEPARATOR

    DOEpatents

    Blewett, J.P.; Kiesling, J.D.

    1963-06-11

    A wave-guide resonator structure is designed for use in separating particles of equal momentum but differing in mass, having energies exceeding one billion eiectron volts. The particles referred to are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high energy accelerator. In the resonator a travelling electric wave is produced which travels at the same rate of speed as the unwanted particle which is thus deflected continuously over the length of the resonator. The wanted particle is slightly out of phase with the travelling wave so that over the whole length of the resonator it has a net deflection of substantially zero. The travelling wave is established in a wave guide of rectangular cross section in which stubs are provided to store magnetic wave energy leaving the electric wave energy in the main structure to obtain the desired travelling wave and deflection. The stubs are of such shape and spacing to establish a critical mathemitical relationship. (AEC)

  2. Resonance Ionization, Mass Spectrometry.

    ERIC Educational Resources Information Center

    Young, J. P.; And Others

    1989-01-01

    Discussed is an analytical technique that uses photons from lasers to resonantly excite an electron from some initial state of a gaseous atom through various excited states of the atom or molecule. Described are the apparatus, some analytical applications, and the precision and accuracy of the technique. Lists 26 references. (CW)

  3. Parametric Resonance Revisited

    NASA Astrophysics Data System (ADS)

    van den Broeck, C.; Bena, I.

    The phenomenon of parametric resonance is revisited. Several physical examples are reviewed and an exactly solvable model is discussed. A mean field theory is presented for globally coupled parametric oscillators with randomly distributed phases. A new type of collective instability appears, which is similar in nature to that of noise induced phase transitions.

  4. Functional Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  5. Micromachined double resonator

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman (Inventor); Tang, Tony K. (Inventor); Shcheglov, Kirill (Inventor)

    2002-01-01

    A micromachined resonator mountable to an external support structure has a proof mass coupled to a base structure by a first spring structure, the base structure having a plurality of electrodes, and a second spring structure coupling the base structure to the external support structure.

  6. Magnetic resonance imaging

    SciTech Connect

    Stark, D.D.; Bradley, W.G. Jr.

    1988-01-01

    The authors present a review of magnetic resonance imaging. Many topics are explored from instrumentation, spectroscopy, blood flow and sodium imaging to detailed clinical applications such as the differential diagnosis of multiple sclerosis or adrenal adenoma. The emphasis throughout is on descriptions of normal multiplanar anatomy and pathology as displayed by MRI.

  7. Double resonator cantilever accelerometer

    DOEpatents

    Koehler, D.R.

    1982-09-23

    A digital quartz accelerometer includes a pair of spaced double-ended tuning forks fastened at one end to a base and at the other end through a spacer mass. Transverse movement of the resonator members stresses one and compresses the other, providing a differential frequency output which is indicative of acceleration.

  8. Double resonator cantilever accelerometer

    DOEpatents

    Koehler, Dale R.

    1984-01-01

    A digital quartz accelerometer includes a pair of spaced double-ended tuning forks fastened at one end to a base and at the other end through a spacer mass. Transverse movement of the resonator members stresses one and compresses the other, providing a differential frequency output which is indicative of acceleration.

  9. Simulation of quartz resonators

    NASA Astrophysics Data System (ADS)

    Weinmann, M.; Radius, R.; Mohr, R.

    Quartz resonators are suitable as novel sensor elements in the field of profilometry and three dimensional measurement techniques. This application requires a tailoring of the oscillator circuit which is performed by a network analysis program. The equivalent network parameters are computed by a finite element analysis. The mechanical loading of the quartz is modeled by a viscous damping approach.

  10. Single spin magnetic resonance.

    PubMed

    Wrachtrup, Jörg; Finkler, Amit

    2016-08-01

    Different approaches have improved the sensitivity of either electron or nuclear magnetic resonance to the single spin level. For optical detection it has essentially become routine to observe a single electron spin or nuclear spin. Typically, the systems in use are carefully designed to allow for single spin detection and manipulation, and of those systems, diamond spin defects rank very high, being so robust that they can be addressed, read out and coherently controlled even under ambient conditions and in a versatile set of nanostructures. This renders them as a new type of sensor, which has been shown to detect single electron and nuclear spins among other quantities like force, pressure and temperature. Adapting pulse sequences from classic NMR and EPR, and combined with high resolution optical microscopy, proximity to the target sample and nanoscale size, the diamond sensors have the potential to constitute a new class of magnetic resonance detectors with single spin sensitivity. As diamond sensors can be operated under ambient conditions, they offer potential application across a multitude of disciplines. Here we review the different existing techniques for magnetic resonance, with a focus on diamond defect spin sensors, showing their potential as versatile sensors for ultra-sensitive magnetic resonance with nanoscale spatial resolution.

  11. Magnetic Resonance Annual, 1985

    SciTech Connect

    Kressel, H.Y.

    1985-01-01

    The inaugural volume of Magnetic Resonance Annual includes reviews of MRI of the posterior fossa, cerebral neoplasms, and the cardiovascular and genitourinary systems. A chapter on contrast materials outlines the mechanisms of paramagnetic contrast enhancement and highlights several promising contrast agents.

  12. Resonant scanning mechanism

    NASA Astrophysics Data System (ADS)

    Wallace, John; Newman, Mike; Gutierrez, Homero; Hoffman, Charlie; Quakenbush, Tim; Waldeck, Dan; Leone, Christopher; Ostaszewski, Miro

    2014-10-01

    Ball Aerospace & Technologies Corp. developed a Resonant Scanning Mechanism (RSM) capable of combining a 250- Hz resonant scan about one axis with a two-hertz triangular scan about the orthogonal axis. The RSM enables a rapid, high-density scan over a significant field of regard (FOR) while minimizing size, weight, and power requirements. The azimuth scan axis is bearing mounted allowing for 30° of mechanical travel, while the resonant elevation axis is flexure and spring mounted with five degrees of mechanical travel. Pointing-knowledge error during quiescent static pointing at room temperature across the full range is better than 100 μrad RMS per axis. The compact design of the RSM, roughly the size of a soda can, makes it an ideal mechanism for use on low-altitude aircraft and unmanned aerial vehicles. Unique aspects of the opto-mechanical design include i) resonant springs which allow for a high-frequency scan axis with low power consumption; and ii) an independent lower-frequency scan axis allowing for a wide FOR. The pointing control system operates each axis independently and employs i) a position loop for the azimuth axis; and ii) a unique combination of parallel frequency and amplitude control loops for the elevation axis. All control and pointing algorithms are hosted on a 200-MHz microcontroller with 516 KB of RAM on a compact 3"×4" digital controller, also of Ball design.

  13. Single spin magnetic resonance

    NASA Astrophysics Data System (ADS)

    Wrachtrup, Jörg; Finkler, Amit

    2016-08-01

    Different approaches have improved the sensitivity of either electron or nuclear magnetic resonance to the single spin level. For optical detection it has essentially become routine to observe a single electron spin or nuclear spin. Typically, the systems in use are carefully designed to allow for single spin detection and manipulation, and of those systems, diamond spin defects rank very high, being so robust that they can be addressed, read out and coherently controlled even under ambient conditions and in a versatile set of nanostructures. This renders them as a new type of sensor, which has been shown to detect single electron and nuclear spins among other quantities like force, pressure and temperature. Adapting pulse sequences from classic NMR and EPR, and combined with high resolution optical microscopy, proximity to the target sample and nanoscale size, the diamond sensors have the potential to constitute a new class of magnetic resonance detectors with single spin sensitivity. As diamond sensors can be operated under ambient conditions, they offer potential application across a multitude of disciplines. Here we review the different existing techniques for magnetic resonance, with a focus on diamond defect spin sensors, showing their potential as versatile sensors for ultra-sensitive magnetic resonance with nanoscale spatial resolution.

  14. Wireless ferroelectric resonating sensor.

    PubMed

    Viikari, Ville; Seppa, Heikki; Mattila, Tomi; Alastalo, Ari

    2010-04-01

    This paper presents a passive wireless resonating sensor that is based on a ferroelectric varactor. The sensor replies with its data at an intermodulation frequency when a reader device illuminates it at 2 closely located frequencies. The paper derives a theoretical equation for the response of such a sensor, verifies the theory by simulations, and demonstrates a temperature sensor based on a ferroelectric varactor.

  15. Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy in Dementias

    PubMed Central

    Hsu, Yuan-Yu; Du, An-Tao; Schuff, Norbert; Weiner, Michael W.

    2007-01-01

    This article reviews recent studies of magnetic resonance imaging and magnetic resonance spectroscopy in dementia, including Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, idiopathic Parkinson's disease, Huntington's disease, and vascular dementia. Magnetic resonance imaging and magnetic resonance spectroscopy can detect structural alteration and biochemical abnormalities in the brain of demented subjects and may help in the differential diagnosis and early detection of affected individuals, monitoring disease progression, and evaluation of therapeutic effect. PMID:11563438

  16. Changing resonator geometry to boost sound power decouples size and song frequency in a small insect.

    PubMed

    Mhatre, Natasha; Montealegre-Z, Fernando; Balakrishnan, Rohini; Robert, Daniel

    2012-05-29

    Despite their small size, some insects, such as crickets, can produce high amplitude mating songs by rubbing their wings together. By exploiting structural resonance for sound radiation, crickets broadcast species-specific songs at a sharply tuned frequency. Such songs enhance the range of signal transmission, contain information about the signaler's quality, and allow mate choice. The production of pure tones requires elaborate structural mechanisms that control and sustain resonance at the species-specific frequency. Tree crickets differ sharply from this scheme. Although they use a resonant system to produce sound, tree crickets can produce high amplitude songs at different frequencies, varying by as much as an octave. Based on an investigation of the driving mechanism and the resonant system, using laser Doppler vibrometry and finite element modeling, we show that it is the distinctive geometry of the crickets' forewings (the resonant system) that is responsible for their capacity to vary frequency. The long, enlarged wings enable the production of high amplitude songs; however, as a mechanical consequence of the high aspect ratio, the resonant structures have multiple resonant modes that are similar in frequency. The drive produced by the singing apparatus cannot, therefore, be locked to a single frequency, and different resonant modes can easily be engaged, allowing individual males to vary the carrier frequency of their songs. Such flexibility in sound production, decoupling body size and song frequency, has important implications for conventional views of mate choice, and offers inspiration for the design of miniature, multifrequency, resonant acoustic radiators.

  17. Squeezing Alters Frequency Tuning of WGM Optical Resonator

    NASA Technical Reports Server (NTRS)

    Mohageg, Makan; Maleki, Lute

    2010-01-01

    Mechanical squeezing has been found to alter the frequency tuning of a whispering-gallery-mode (WGM) optical resonator that has an elliptical shape and is made of lithium niobate. It may be possible to exploit this effect to design reconfigurable optical filters for optical communications and for scientific experiments involving quantum electrodynamics. Some background information is prerequisite to a meaningful description of the squeezing-induced alteration of frequency tuning: The spectrum of a WGM resonator is represented by a comblike plot of intensity versus frequency. Each peak of the comblike plot corresponds to an electromagnetic mode represented by an integer mode number, and the modes are grouped into sets represented by integer mode indices. Because lithium niobate is an electro-optically active material, the WGM resonator can be tuned (that is, the resonance frequencies can be shifted) by applying a suitable bias potential. The frequency shift of each mode is quantified by a tuning rate defined as the ratio between the frequency shift and the applied potential. In the absence of squeezing, all modes exhibit the same tuning rate. This concludes the background information. It has been demonstrated experimentally that when the resonator is squeezed along part of either of its two principal axes, tuning rates differ among the groups of modes represented by different indices (see figure). The differences in tuning rates could be utilized to configure the resonance spectrum to obtain a desired effect; for example, through a combination of squeezing and electrical biasing, two resonances represented by different mode indices could be set at a specified frequency difference something that could not be done through electrical biasing alone.

  18. Coherent synchro-betatron resonance

    SciTech Connect

    Burov, A.; Lebedev, V.; /Fermilab

    2006-12-01

    Coherent synchro-betatron resonances can present a serious limit for low-energy synchrotrons with strong space charge. Here, an excitation of a dipole transverse mode is considered at resonance condition.

  19. Rare earth elements exploitation, geopolitical implications and raw materials trading

    NASA Astrophysics Data System (ADS)

    Chemin, Marie-Charlotte

    2015-04-01

    Rare earth elements (REE) correspond to seventeen elements of the periodic table. They are used in high technology, cracking, electric cars' magnet, metal alloy for batteries, and also in phone construction or ceramics for electronic card. REEs are an important resource for high technology. This project targets 16 years old students in the subject "personalized aid" and will last six weeks. The purpose of this project is to develop autonomy and research in groups for a transdisciplinary work. This project gathers knowledge in geology, geography and economics. During the first session students analyze the geology applications of the REE. They begin the analysis with learning the composition in different rocks such as basalt and diorite to make the link with crystallization. Then they compare it with adakite to understand the formation of these rocks. In the second session, they study REE exploitation. We can find them as oxides in many deposits. The principal concentrations of rare earth elements are associated with uncommon varieties of igneous rocks, such as carbonatites. They can use Qgis, to localize this high concentration. In the third session, they study the environmental costs of REE exploitation. Indeed, the exploitation produces thorium and carcinogenic toxins: sulphates, ammonia and hydrochloric acid. Processing one ton of rare earths produces 2,000 tons of toxic waste. This session focuses, first, on Baotou's region, and then on an example they are free to choose. In the fourth session, they study the geopolitical issues of REE with a focus on China. In fact this country is the largest producer of REE, and is providing 95% of the overall production. REE in China are at the center of a geopolitical strategy. In fact, China implements a sort of protectionism. Indeed, the export tax on REE is very high so, as a foreign company, it is financially attractive to establish a manufacturing subsidiary in China in order to use REE. As a matter of fact

  20. Separating hyperfine from spin-orbit interactions in organic semiconductors by multi-octave magnetic resonance using coplanar waveguide microresonators

    NASA Astrophysics Data System (ADS)

    Joshi, G.; Miller, R.; Ogden, L.; Kavand, M.; Jamali, S.; Ambal, K.; Venkatesh, S.; Schurig, D.; Malissa, H.; Lupton, J. M.; Boehme, C.

    2016-09-01

    Separating the influence of hyperfine from spin-orbit interactions in spin-dependent carrier recombination and dissociation processes necessitates magnetic resonance spectroscopy over a wide range of frequencies. We have designed compact and versatile coplanar waveguide resonators for continuous-wave electrically detected magnetic resonance and tested these on organic light-emitting diodes. By exploiting both the fundamental and higher-harmonic modes of the resonators, we cover almost five octaves in resonance frequency within a single setup. The measurements with a common π-conjugated polymer as the active material reveal small but non-negligible effects of spin-orbit interactions, which give rise to a broadening of the magnetic resonance spectrum with increasing frequency.

  1. Equivalent circuit for birdcage resonators.

    PubMed

    Harpen, M D

    1993-02-01

    We present an equivalent circuit analysis for both low pass and high pass birdcage resonators loaded with lossy samples. In a generalization of the method of Hoult and Lauterbur (J. Magn. Reson. 34, 425 (1979)), we also derive circuit component values by application of the laws of electrodynamics. Measured resonance spectra, quality factors, and feed point impedances in a test resonator are shown to be in agreement with those predicted by the proposed model.

  2. Species succession and fishery exploitation in the Great Lakes

    USGS Publications Warehouse

    Smith, Stanford H.

    1968-01-01

    The species composition of fish in the Great Lakes has undergone continual change since the earliest records. Some changes were caused by enrichment of the environment, but others primarily by an intensive and selective fishery for certain species. Major changes related to the fishery were less frequent before the late 1930's than in recent years and involved few species. Lake sturgeon (Acipenser fulvescens) were overexploited knowingly during the late 1800's because they interfered with fishing for preferred species; sturgeon were greatly reduced in all lakes by the early 1900's. Heavy exploitation accompanied sharp declines of lake herring (Leucichthys artedi) in Lake Erie during the 1920's and lake whitefish (Coregonus clupeaformis) in Lake Huron during the 1930's. A rapid succession of fish species in Lakes Huron, Michigan, and Superior that started about 1940 has been caused by selective predation by the sea lamprey (Petromyzon marinus) on native predatory species, and the resultant shifting emphasis of the fishery and species interaction as various species declined. Lake trout (Salvelinus namaycush) and burbot (Lota lota), the deepwater predators, were depleted first; this favored their prey, the chubs (Leucichthys spp.). The seven species of chubs were influenced differently according to differences in size. Fishing emphasis and predation by sea lampreys were selective for the largest species of chubs as lake trout and burbot declined. A single slow-growing chub, the bloater, was favored and increased, but as the large chubs declined the bloater was exploited by a new trawl fishery. The growth rate and size of the bloater increased, making it more vulnerable to conventional gillnet fishery and lamprey predation. This situation in Lakes Michigan and Huron favored the small alewife (Alosa pseudoharengus) which had recently become established in the upper Great Lakes, and the alewife increased rapidly and dominated the fish stocks of the lakes. The successive

  3. Determination and Therapeutic Exploitation of Ebola Virus Spontaneous Mutation Frequency

    PubMed Central

    Alfson, Kendra J.; Worwa, Gabriella; Carrion, Ricardo

    2015-01-01

    ABSTRACT Ebola virus (EBOV) is an RNA virus that can cause hemorrhagic fever with high fatality rates, and there are no approved vaccines or therapies. Typically, RNA viruses have high spontaneous mutation rates, which permit rapid adaptation to selection pressures and have other important biological consequences. However, it is unknown if filoviruses exhibit high mutation frequencies. Ultradeep sequencing and a recombinant EBOV that carries the gene encoding green fluorescent protein were used to determine the spontaneous mutation frequency of EBOV. The effects of the guanosine analogue ribavirin during EBOV infections were also assessed. Ultradeep sequencing revealed that the mutation frequency for EBOV was high and similar to those of other RNA viruses. Interestingly, significant genetic diversity was not observed in viable viruses, implying that changes were not well tolerated. We hypothesized that this could be exploited therapeutically. In vitro, the presence of ribavirin increased the error rate, and the 50% inhibitory concentration (IC50) was 27 μM. In a mouse model of ribavirin therapy given pre-EBOV exposure, ribavirin treatment corresponded with a significant delay in time to death and up to 75% survival. In mouse and monkey models of therapy given post-EBOV exposure, ribavirin treatment also delayed the time to death and increased survival. These results demonstrate that EBOV has a spontaneous mutation frequency similar to those of other RNA viruses. These data also suggest a potential for therapeutic use of ribavirin for human EBOV infections. IMPORTANCE Ebola virus (EBOV) causes a severe hemorrhagic disease with high case fatality rates; there are no approved vaccines or therapies. We determined the spontaneous mutation frequency of EBOV, which is relevant to understanding the potential for the virus to adapt. The frequency was similar to those of other RNA viruses. Significant genetic diversity was not observed in viable viruses, implying that

  4. Coherent optical non-reciprocity in axisymmetric resonators.

    PubMed

    Lenferink, Erik J; Wei, Guohua; Stern, Nathaniel P

    2014-06-30

    We describe an approach to optical non-reciprocity that exploits the local helicity of evanescent electric fields in axisymmetric resonators. By interfacing an optical cavity to helicity-sensitive transitions, such as Zeeman levels in a quantum dot, light transmission through a waveguide becomes direction-dependent when the state degeneracy is lifted. Using a linearized quantum master equation, we analyze the configurations that exhibit non-reciprocity, and we show that reasonable parameters from existing cavity QED experiments are sufficient to demonstrate a coherent non-reciprocal optical isolator operating at the level of a single photon.

  5. Relaxation time based classification of magnetic resonance brain images

    NASA Astrophysics Data System (ADS)

    Baselice, Fabio; Ferraioli, Giampaolo; Pascazio, Vito

    2015-03-01

    Brain tissue classification in Magnetic Resonance Imaging is useful for a wide range of applications. Within this manuscript a novel approach for brain tissue joint segmentation and classification is presented. Starting from the relaxation time estimation, we propose a novel method for identifying the optimal decision regions. The approach exploits the statistical distribution of the involved signals in the complex domain. The technique, compared to classical threshold based ones, is able to improve the correct classification rate. The effectiveness of the approach is evaluated on a simulated case study.

  6. Hybridised exciton–polariton resonances in core–shell nanoparticles

    NASA Astrophysics Data System (ADS)

    Gentile, Martin J.; Barnes, William L.

    2017-03-01

    The goal of nanophotonics is to control and manipulate light at length scales below the diffraction limit. Typically nanostructured metals are used for this purpose, light being confined by exploiting the surface plasmon–polaritons such structures support. Recently excitonic (molecular) materials have been identified as an alternative candidate material for nanophotonics. Here we use theoretical modelling to explore how hybridisation of surface exciton–polaritons can be achieved through appropriate nanostructuring. We focus on the extent to which the frequency of the hybridised modes can be shifted with respect to the underlying material resonances.

  7. Diamond electro-optomechanical resonators integrated in nanophotonic circuits

    SciTech Connect

    Rath, P.; Ummethala, S.; Pernice, W. H. P.; Diewald, S.; Lewes-Malandrakis, G.; Brink, D.; Heidrich, N.; Nebel, C.

    2014-12-22

    Diamond integrated photonic devices are promising candidates for emerging applications in nanophotonics and quantum optics. Here, we demonstrate active modulation of diamond nanophotonic circuits by exploiting mechanical degrees of freedom in free-standing diamond electro-optomechanical resonators. We obtain high quality factors up to 9600, allowing us to read out the driven nanomechanical response with integrated optical interferometers with high sensitivity. We are able to excite higher order mechanical modes up to 115 MHz and observe the nanomechanical response also under ambient conditions.

  8. Measuring Traces Of Oxygen By Resonant Electron Attachment

    NASA Technical Reports Server (NTRS)

    Man, Kin Fung; Boumsellek, Said; Chutjian, Ara

    1995-01-01

    Method of detecting trace amounts of oxygen based on dissociative attachment of electrons to oxygen molecules followed by measurement of resulting flux of negative oxygen ions in mass spectrometer. High sensitivity achieved in method by exploiting resonance in dissociative attachment of electrons to oxygen molecules: electron-attachment cross section rises to high peak at incident electron kinetic energy of 6.2 eV. Relative concentrations below 1 ppb detected. Devised to increase sensitivity of detection of oxygen in processing chambers in which oxygen regarded as contaminant; for example, chambers used in making semiconductor devices and in growing high-purity crystals.

  9. Technical considerations for functional magnetic resonance imaging analysis.

    PubMed

    Conklin, Chris J; Faro, Scott H; Mohamed, Feroze B

    2014-11-01

    Clinical application of functional magnetic resonance imaging (fMRI) based on blood oxygenation level-dependent (BOLD) effect has increased over the past decade because of its ability to map regional blood flow in response to brain stimulation. This mapping is primarily achieved by exploiting the BOLD effect precipitated by changes in the magnetic properties of hemoglobin. BOLD fMRI has utility in neurosurgical planning and mapping neuronal functional connectivity. Conventional echo planar imaging techniques are used to acquire stimulus-driven fMR imaging BOLD data. This article highlights technical aspects of fMRI data analysis to make it more accessible in clinical settings.

  10. Magnetic Resonance Facility (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    This fact sheet provides information about Magnetic Resonance Facility capabilities and applications at NREL's National Bioenergy Center. Liquid and solid-state analysis capability for a variety of biomass, photovoltaic, and materials characterization applications across NREL. NREL scientists analyze solid and liquid samples on three nuclear magnetic resonance (NMR) spectrometers as well as an electron paramagnetic resonance (EPR) spectrometer.

  11. Secondary resonances of electrically actuated resonant microsensors

    NASA Astrophysics Data System (ADS)

    Abdel-Rahman, Eihab M.; Nayfeh, Ali H.

    2003-05-01

    We investigate the response of a microbeam-based resonant sensor to superharmonic and subharmonic electric actuations using a model that incorporates the nonlinearities associated with moderately large displacements and electric forces. The method of multiple scales is used, in each case, to obtain two first-order nonlinear ordinary-differential equations that describe the modulation of the amplitude and phase of the response and its stability. We present typical frequency-response and force-response curves demonstrating, in both cases, the coexistence of multivalued solutions. The solution corresponding to a superharmonic excitation consists of three branches, which meet at two saddle-node bifurcation points. The solution corresponding to a subharmonic excitation consists of two branches meeting a branch of trivial solutions at two pitchfork bifurcation points. One of these bifurcation points is supercritical and the other is subcritical. The results provide an analytical tool to predict the microsensor response to superharmonic and subharmonic excitations, specifically the locations of sudden jumps and regions of hysteretic behavior, thereby enabling designers to safely use these frequencies as measurement signals. They also allow designers to examine the impact of various design parameters on the device behavior.

  12. WGM Resonators for Terahertz-to-Optical Frequency Conversion

    NASA Technical Reports Server (NTRS)

    Strekalov,Dmitry; Savchenkov, Anatoliy; Matsko, Andrey; Nu, Nan

    2008-01-01

    Progress has been made toward solving some practical problems in the implementation of terahertz-to-optical frequency converters utilizing whispering-gallery-mode (WGM) resonators. Such frequency converters are expected to be essential parts of non-cryogenic terahertz- radiation receivers that are, variously, under development or contemplated for a variety of applications in airborne and spaceborne instrumentation for astronomical and military uses. In most respects, the basic principles of terahertz-to-optical frequency conversion in WGM resonators are the same as those of microwave (sub-terahertz)-to-optical frequency conversion in WGM resonators, various aspects of which were discussed in the three preceeding articles. To recapitulate: In a receiver following this approach, a preamplified incoming microwave signal (in the present case, a terahertz signal) is up-converted to an optical signal by a technique that exploits the nonlinearity of the electromagnetic response of a whispering-gallery-mode (WGM) resonator made of LiNbO3 or another suitable electro-optical material. Upconversion takes place by three-wave mixing in the resonator. To ensure the required interaction among the optical and terahertz signals, the WGM resonator must be designed and fabricated to function as an electro-optical modulator while simultaneously exhibiting (1) resonance at the required microwave and optical operating frequencies and (2) phase matching among the microwave and optical signals circulating in the resonator. Downstream of the WGM resonator, the up-converted signal is processed photonically by use of a tunable optical filter or local oscillator and is then detected. The practical problems addressed in the present development effort are the following: Satisfaction of the optical and terahertz resonance-frequency requirement is a straightforward matter, inasmuch as the optical and terahertz spectra can be measured. However, satisfaction of the phase-matching requirement is

  13. Resonant Cascaded Downconversion

    SciTech Connect

    Weedbrook, Christian; Parrett, Ben; Kheruntsyan, Karen; Drummond, Peter; Pooser, Raphael C; Pfister, Olivier

    2012-01-01

    We analyze an optical parametric oscillator (OPO) in which cascaded down-conversion occurs inside a cavity resonant for all modes but the initial pump. Due to the resonant cascade design, the OPO presents two {chi}{sup (2)}-level oscillation thresholds that are therefore much lower than for a {chi}{sup (3)} OPO. This is promising for reaching the regime of an effective third-order nonlinearity well above both thresholds. Such a {chi}{sup (2)} cascaded device also has potential applications in frequency conversion to far-infrared regimes. But, most importantly, it can generate novel multipartite quantum correlations in the output radiation, which represent a step beyond squeezed or entangled light. The output can be highly non-Gaussian and therefore not describable by any semiclassical model. In this paper, we derive quantum stochastic equations in the positive-P representation and undertake an analysis of steady-state and dynamical properties of this system.

  14. RESONANT CAVITY EXCITATION SYSTEM

    DOEpatents

    Baker, W.R.; Kerns, Q.A.; Riedel, J.

    1959-01-13

    An apparatus is presented for exciting a cavity resonator with a minimum of difficulty and, more specifically describes a sub-exciter and an amplifier type pre-exciter for the high-frequency cxcitation of large cavities. Instead of applying full voltage to the main oscillator, a sub-excitation voltage is initially used to establish a base level of oscillation in the cavity. A portion of the cavity encrgy is coupled to the input of the pre-exciter where it is amplified and fed back into the cavity when the pre-exciter is energized. After the voltage in the cavity resonator has reached maximum value under excitation by the pre-exciter, full voltage is applied to the oscillator and the pre-exciter is tunned off. The cavity is then excited to the maximum high voltage value of radio frequency by the oscillator.

  15. Resonant magnetic vortices

    SciTech Connect

    Decanini, Yves; Folacci, Antoine

    2003-04-01

    By using the complex angular momentum method, we provide a semiclassical analysis of electron scattering by a magnetic vortex of Aharonov-Bohm type. Regge poles of the S matrix are associated with surface waves orbiting around the vortex and supported by a magnetic field discontinuity. Rapid variations of sharp characteristic shapes can be observed on scattering cross sections. They correspond to quasibound states which are Breit-Wigner-type resonances associated with surface waves and which can be considered as quantum analogues of acoustic whispering-gallery modes. Such a resonant magnetic vortex could provide a different kind of artificial atom while the semiclassical approach developed here could be profitably extended in various areas of the physics of vortices.

  16. Image Registration Through The Exploitation Of Perspective Invariant Graphs

    NASA Astrophysics Data System (ADS)

    Gilmore, John F.

    1983-10-01

    This paper describes two new techniques of image registration as applied to scenes consisting of natural terrain. The first technique is a syntactic pattern recognition approach which combines the spatial relationships of a point pattern with point classifications to accurately perform image registration. In this approach, a preprocessor analyzes each image in order to identify points of interest and to classify these points based on statistical features. A classified graph possessing perspective invariant properties is created and is converted into a classification-based grammar string. A local match analysis is performed and the best global match is con-structed. A probability-of-match metric is computed in order to evaluate match confidence. The second technique described is an isomorphic graph matching approach called Mean Neighbors (MN). A MN graph is constructed from a given point pattern taking into account the elliptical projections of real world scenes onto a two dimensional surface. This approach exploits the spatial relationships of the given points of interest but neglects the point classifications used in syntactic processing. A projective, perspective invariant graph is constructed for both the reference and sensed images and a mapping of the coincidence edges occurs. A probability of match metric is used to evaluate the confidence of the best mapping.

  17. Exploitation of parallelism in climate models. Final report

    SciTech Connect

    Baer, Ferdinand; Tribbia, Joseph J.; Williamson, David L.

    2001-02-05

    This final report includes details on the research accomplished by the grant entitled 'Exploitation of Parallelism in Climate Models' to the University of Maryland. The purpose of the grant was to shed light on (a) how to reconfigure the atmospheric prediction equations such that the time iteration process could be compressed by use of MPP architecture; (b) how to develop local subgrid scale models which can provide time and space dependent parameterization for a state-of-the-art climate model to minimize the scale resolution necessary for a climate model, and to utilize MPP capability to simultaneously integrate those subgrid models and their statistics; and (c) how to capitalize on the MPP architecture to study the inherent ensemble nature of the climate problem. In the process of addressing these issues, we created parallel algorithms with spectral accuracy; we developed a process for concurrent climate simulations; we established suitable model reconstructions to speed up computation; we identified and tested optimum realization statistics; we undertook a number of parameterization studies to better understand model physics; and we studied the impact of subgrid scale motions and their parameterization in atmospheric models.

  18. Exploitation of syndecan-1 shedding by Pseudomonas aeruginosa enhances virulence.

    PubMed

    Park, P W; Pier, G B; Hinkes, M T; Bernfield, M

    2001-05-03

    Cell-surface heparan sulphate proteoglycans (HSPGs) are ubiquitous and abundant receptors/co-receptors of extracellular ligands, including many microbes. Their role in microbial infections is poorly defined, however, because no cell-surface HSPG has been clearly connected to the pathogenesis of a particular microbe. We have previously shown that Pseudomonas aeruginosa, through its virulence factor LasA, enhances the in vitro shedding of syndecan-1-the predominant cell-surface HSPG of epithelia. Here we show that shedding of syndecan-1 is also activated by P. aeruginosa in vivo, and that the resulting syndecan-1 ectodomains enhance bacterial virulence in newborn mice. Newborn mice deficient in syndecan-1 resist P. aeruginosa lung infection but become susceptible when given purified syndecan-1 ectodomains or heparin, but not when given ectodomain core protein, indicating that the ectodomain's heparan sulphate chains are the effectors. In wild-type newborn mice, inhibition of syndecan-1 shedding or inactivation of the shed ectodomain's heparan sulphate chains prevents lung infection. Our findings uncover a pathogenetic mechanism in which a host response to tissue injury-syndecan-1 shedding-is exploited to enhance microbial virulence apparently by modulating host defences.

  19. Exploiting features of adenovirus replication to support mammalian kinase production

    PubMed Central

    Cotten, Matt; Stegmueller, Kerstin; Eickhoff, Jan; Hanke, Miriam; Herzberger, Katrin; Herget, Thomas; Choidas, Axel; Daub, Henrik; Godl, Klaus

    2003-01-01

    Faced with the current wealth of genomic data, it is essential to have robust and reliable methods of converting DNA sequences into their functional gene products. We demonstrate here that when conditions are established that take advantage of the replication-associated virus amplification, the virus-induced shutdown of host protein synthesis as well as the activation of signalling pathways that normally occur during virus replication, adenovirus biology can be exploited to generate a potent kinase expression system. Residual virus in the protein production has always been a limitation for adenovirus systems and we describe a DNA intercalator/ultraviolet light treatment that eliminates residual adenovirus in protein preparations that has no deleterious effect on enzyme activity. The use of mammalian cells in combination with adenovirus generated a variety of active enzymes which could not be produced in Escherichia coli or baculovirus-infected insect cells. Thus, the utility of adenovirus-mediated enzyme expression as a versatile alternative to established protein production technologies is demonstrated. PMID:14576328

  20. Exploiting features of adenovirus replication to support mammalian kinase production.

    PubMed

    Cotten, Matt; Stegmueller, Kerstin; Eickhoff, Jan; Hanke, Miriam; Herzberger, Katrin; Herget, Thomas; Choidas, Axel; Daub, Henrik; Godl, Klaus

    2003-11-01

    Faced with the current wealth of genomic data, it is essential to have robust and reliable methods of converting DNA sequences into their functional gene products. We demonstrate here that when conditions are established that take advantage of the replication-associated virus amplification, the virus-induced shutdown of host protein synthesis as well as the activation of signalling pathways that normally occur during virus replication, adenovirus biology can be exploited to generate a potent kinase expression system. Residual virus in the protein production has always been a limitation for adenovirus systems and we describe a DNA intercalator/ultraviolet light treatment that eliminates residual adenovirus in protein preparations that has no deleterious effect on enzyme activity. The use of mammalian cells in combination with adenovirus generated a variety of active enzymes which could not be produced in Escherichia coli or baculovirus-infected insect cells. Thus, the utility of adenovirus-mediated enzyme expression as a versatile alternative to established protein production technologies is demonstrated.

  1. Efficient terrestrial laser scan segmentation exploiting data structure

    NASA Astrophysics Data System (ADS)

    Mahmoudabadi, Hamid; Olsen, Michael J.; Todorovic, Sinisa

    2016-09-01

    New technologies such as lidar enable the rapid collection of massive datasets to model a 3D scene as a point cloud. However, while hardware technology continues to advance, processing 3D point clouds into informative models remains complex and time consuming. A common approach to increase processing efficiently is to segment the point cloud into smaller sections. This paper proposes a novel approach for point cloud segmentation using computer vision algorithms to analyze panoramic representations of individual laser scans. These panoramas can be quickly created using an inherent neighborhood structure that is established during the scanning process, which scans at fixed angular increments in a cylindrical or spherical coordinate system. In the proposed approach, a selected image segmentation algorithm is applied on several input layers exploiting this angular structure including laser intensity, range, normal vectors, and color information. These segments are then mapped back to the 3D point cloud so that modeling can be completed more efficiently. This approach does not depend on pre-defined mathematical models and consequently setting parameters for them. Unlike common geometrical point cloud segmentation methods, the proposed method employs the colorimetric and intensity data as another source of information. The proposed algorithm is demonstrated on several datasets encompassing variety of scenes and objects. Results show a very high perceptual (visual) level of segmentation and thereby the feasibility of the proposed algorithm. The proposed method is also more efficient compared to Random Sample Consensus (RANSAC), which is a common approach for point cloud segmentation.

  2. Separating mixtures by exploiting molecular packing effects in microporous materials.

    PubMed

    Krishna, Rajamani

    2015-01-07

    We examine mixture separations with microporous adsorbents such as zeolites, metal-organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs), operating under conditions close to pore saturation. Pore saturation is realized, for example, when separating bulk liquid phase mixtures of polar compounds such as water, alcohols and ketones. For the operating conditions used in industrial practice, pore saturation is also attained in separations of hydrocarbon mixtures such as xylene isomers and hexane isomers. Separations under pore saturation conditions are strongly influenced by differences in the saturation capacities of the constituent species; the adsorption is often in favor of the component with the higher saturation capacity. Effective separations are achieved by exploiting differences in the efficiency with which molecules pack within the ordered crystalline porous materials. For mixtures of chain alcohols, the shorter alcohol can be preferentially adsorbed because of its higher saturation capacity. With hydrophilic adsorbents, water can be selectively adsorbed from water-alcohol mixtures. For separations of o-xylene-m-xylene-p-xylene mixtures, the pore dimensions of MOFs can be tailored in such a manner as to allow optimal packing of the isomer that needs to be adsorbed preferentially. Subtle configurational differences between linear and branched alkane isomers result in significantly different packing efficiencies within the pore topology of MFI, AFI, ATS, and CFI zeolites. A common characteristic feature of most separations that are reliant on molecular packing effects is that adsorption and intra-crystalline diffusion are synergistic; this enhances the separation efficiencies in fixed bed adsorbers.

  3. Drug development from natural products: exploiting synergistic effects.

    PubMed

    Ulrich-Merzenich, Gudrun; Panek, D; Zeitler, H; Vetter, H; Wagner, H

    2010-03-01

    Drug development in phytomedicine has been focused in the past on the discovery and analysis of new structures from natural products. The search aimed at the determination of the single "active principle" in plants, based on the assumption that a plant has one or a few ingredients which determine its therapeutic effects. But traditional systems of medicines like Ayurveda, traditional Chinese medicine or the European phytotherapy generally assume that a synergy of all ingredients of the plants will bring about the maximum of therapeutic efficacy. This approach has for long been impossible to investigate since adequate methods to standardize complex plant mixtures as well as to rationalize complex mode of actions were lacking. The introduction of high throughput technologies provides the opportunity to determine profiles of plants and to systematically explore the mode of action of combinatory drug regimes. The present review highlights the concept of synergy and gives examples of synergistic effects of plant constituents. It elaborates on how the high throughput technologies can be used in drug development from natural products with the aim of creating evidence-based plant medications in prevention and treatment of different diseases in the form of new single treatments or new combinatory drug regimes while exploiting synergy-effects.

  4. Exploitation of a large COSMO-SkyMed interferometric dataset

    NASA Astrophysics Data System (ADS)

    Nutricato, Raffaele; Nitti, Davide O.; Bovenga, Fabio; Refice, Alberto; Chiaradia, Maria T.

    2014-10-01

    In this work we explored a dataset made by more than 100 images acquired by COSMO-SkyMed (CSK) constellation over the Port-au-Prince (Haiti) metropolitan and surrounding areas that were severely hit by the January 12th, 2010 earthquake. The images were acquired along ascending pass by all the four sensors of the constellation with a mean rate of 1 acquisition/week. This consistent CSK dataset was fully exploited by using the Persistent Scatterer Interferometry algorithm SPINUA with the aim of: i) providing a displacement map of the area; ii) assessing the use of CSK and PSI for ground elevation measurements; iii) exploring the CSK satellite orbital tube in terms of both precision and size. In particular, significant subsidence phenomena were detected affecting river deltas and coastal areas of the Port-au-Prince and Carrefour region, as well as very slow slope movements and local ground instabilities. Ground elevation was also measured on PS targets with resolution of 3m. The density of these measurable targets depends on the ground coverage, and reaches values higher than 4000 PS/km2 over urban areas, while it drops over vegetated areas or along slopes affected by layover and shadow. Heights values were compared with LIDAR data at 1m of resolution collected soon after the 2010 earthquake. Furthermore, by using geocoding procedures and the precise LIDAR data as reference, the orbital errors affecting CSK records were investigated. The results are in line with other recent studies.

  5. Method for hyperspectral imagery exploitation and pixel spectral unmixing

    NASA Technical Reports Server (NTRS)

    Lin, Ching-Fang (Inventor)

    2003-01-01

    An efficiently hybrid approach to exploit hyperspectral imagery and unmix spectral pixels. This hybrid approach uses a genetic algorithm to solve the abundance vector for the first pixel of a hyperspectral image cube. This abundance vector is used as initial state in a robust filter to derive the abundance estimate for the next pixel. By using Kalman filter, the abundance estimate for a pixel can be obtained in one iteration procedure which is much fast than genetic algorithm. The output of the robust filter is fed to genetic algorithm again to derive accurate abundance estimate for the current pixel. The using of robust filter solution as starting point of the genetic algorithm speeds up the evolution of the genetic algorithm. After obtaining the accurate abundance estimate, the procedure goes to next pixel, and uses the output of genetic algorithm as the previous state estimate to derive abundance estimate for this pixel using robust filter. And again use the genetic algorithm to derive accurate abundance estimate efficiently based on the robust filter solution. This iteration continues until pixels in a hyperspectral image cube end.

  6. Augmented reality enabling intelligence exploitation at the edge

    NASA Astrophysics Data System (ADS)

    Kase, Sue E.; Roy, Heather; Bowman, Elizabeth K.; Patton, Debra

    2015-05-01

    Today's Warfighters need to make quick decisions while interacting in densely populated environments comprised of friendly, hostile, and neutral host nation locals. However, there is a gap in the real-time processing of big data streams for edge intelligence. We introduce a big data processing pipeline called ARTEA that ingests, monitors, and performs a variety of analytics including noise reduction, pattern identification, and trend and event detection in the context of an area of operations (AOR). Results of the analytics are presented to the Soldier via an augmented reality (AR) device Google Glass (Glass). Non-intrusive AR devices such as Glass can visually communicate contextually relevant alerts to the Soldier based on the current mission objectives, time, location, and observed or sensed activities. This real-time processing and AR presentation approach to knowledge discovery flattens the intelligence hierarchy enabling the edge Soldier to act as a vital and active participant in the analysis process. We report preliminary observations testing ARTEA and Glass in a document exploitation and person of interest scenario simulating edge Soldier participation in the intelligence process in disconnected deployment conditions.

  7. Exploited and excreting: parasite type affects host nutrient recycling.

    PubMed

    Narr, Charlotte F; Frost, Paul C

    2016-08-01

    Parasite-induced changes in the nutrient balance of hosts could alter the availability of nutrients in ecosystems by changing consumer-driven nutrient recycling. While these effects on host nutrient use are mediated by host physiology, they likely depend on characteristics of the parasite and host diet quality. We examined this possibility by measuring nutrient release rates of uninfected Daphnia and conspecifics infected by two microparasites (the bacterium Pasteuria ramosa and the microsporidium Hamiltosporidium tvaerminnensis) from daphnid hosts fed food that varied in phosphorus content. We found that infection type and diet affected host nutrient release rates, but the strength of these effects varied among parasite treatments. To improve our understanding of these effects, we examined whether two separate aspects of host exploitation (parasite-induced reductions in host fecundity and parasite load) could account for variation in Daphnia nutrient release, ingestion, and elemental ratios caused by our infection and diet treatments. Regardless of whether we compared individuals across infection type or diet treatment, Daphnia fecundity described variation in multiple aspects of host nutrient use better than infection, diet, or spore load. Our results suggest that parasite-induced changes in host nutrient use are both parasite and diet specific, and that host fecundity could be a useful parameter for predicting the magnitude and direction of these changes.

  8. The business of exploiting induced pluripotent stem cells

    PubMed Central

    Prescott, Catherine

    2011-01-01

    Induced pluripotent stem cells (iPS cells) can be exploited for both research and clinical applications. The first part of this review seeks to provide an understanding of the financial drivers and key elements of a successful business strategy that underpin a company focused on developing iPS-related products and services targeted at the research market. The latter part of the review highlights some of the reasons as to why the reprogramming of somatic cells is currently being used to develop cell-based models to screen for small molecules with drug-like properties rather than to develop cell-based regenerative medicines per se. The latter may be used to repair or replace a patient's damaged cells and thereby have the potential to ‘cure’ a disease and, in doing so, prevent or delay the onset of associated medical conditions. However, the cost of an expensive regenerative medicine and time to accrue any benefit linked to a decrease in co-morbidity expenditure may not outweigh the benefit for a healthcare community that has finite resources. The implications of this are discussed together with evidence that the UK National Institute for Health and Clinical Excellence (NICE) and the National Health Service (NHS) have established a precedent for a cost-sharing strategy with the pharmaceutical industry. PMID:21727138

  9. Compressive sensing exploiting wavelet-domain dependencies for ECG compression

    NASA Astrophysics Data System (ADS)

    Polania, Luisa F.; Carrillo, Rafael E.; Blanco-Velasco, Manuel; Barner, Kenneth E.

    2012-06-01

    Compressive sensing (CS) is an emerging signal processing paradigm that enables sub-Nyquist sampling of sparse signals. Extensive previous work has exploited the sparse representation of ECG signals in compression applications. In this paper, we propose the use of wavelet domain dependencies to further reduce the number of samples in compressive sensing-based ECG compression while decreasing the computational complexity. R wave events manifest themselves as chains of large coefficients propagating across scales to form a connected subtree of the wavelet coefficient tree. We show that the incorporation of this connectedness as additional prior information into a modified version of the CoSaMP algorithm can significantly reduce the required number of samples to achieve good quality in the reconstruction. This approach also allows more control over the ECG signal reconstruction, in particular, the QRS complex, which is typically distorted when prior information is not included in the recovery. The compression algorithm was tested upon records selected from the MIT-BIH arrhythmia database. Simulation results show that the proposed algorithm leads to high compression ratios associated with low distortion levels relative to state-of-the-art compression algorithms.

  10. Exploiting pallidal plasticity for stimulation in Parkinson’s disease

    NASA Astrophysics Data System (ADS)

    Lourens, Marcel A. J.; Schwab, Bettina C.; Nirody, Jasmine A.; Meijer, Hil G. E.; van Gils, Stephan A.

    2015-04-01

    Objective. Continuous application of high-frequency deep brain stimulation (DBS) often effectively reduces motor symptoms of Parkinson’s disease patients. While there is a growing need for more effective and less traumatic stimulation, the exact mechanism of DBS is still unknown. Here, we present a methodology to exploit the plasticity of GABAergic synapses inside the external globus pallidus (GPe) for the optimization of DBS. Approach. Assuming the existence of spike-timing-dependent plasticity (STDP) at GABAergic GPe-GPe synapses, we simulate neural activity in a network model of the subthalamic nucleus and GPe. In particular, we test different DBS protocols in our model and quantify their influence on neural synchrony. Main results. In an exemplary set of biologically plausible model parameters, we show that STDP in the GPe has a direct influence on neural activity and especially the stability of firing patterns. STDP stabilizes both uncorrelated firing in the healthy state and correlated firing in the parkinsonian state. Alternative stimulation protocols such as coordinated reset stimulation can clearly profit from the stabilizing effect of STDP. These results are widely independent of the STDP learning rule. Significance. Once the model settings, e.g., connection architectures, have been described experimentally, our model can be adjusted and directly applied in the development of novel stimulation protocols. More efficient stimulation leads to both minimization of side effects and savings in battery power.

  11. Exploiting receptor tyrosine kinase co-activation for cancer therapy

    PubMed Central

    Tan, Aik-Choon; Vyse, Simon; Huang, Paul H

    2017-01-01

    Studies over the past decade have shown that Receptor Tyrosine Kinase (RTK) co-activation is prevalent in many cancer types. Compelling data demonstrates that cancers are likely to have evolved RTK co-activation as a generic means for driving tumour growth and providing a buffering system to limit the lethal effects of microenvironmental insults including therapy. In this review, we summarise the general principles of RTK co-activation gleaned from key studies over the last decade. We discuss direct and indirect approaches to exploit RTK co-activation for cancer therapy and describe recent developments in computational approaches to predict kinase co-dependencies by integrating drug screening data and kinase inhibitor selectivity profiles. We offer a perspective on the outstanding questions in the field focusing on the implications of RTK co-activation on tumour heterogeneity and cancer evolution and conclude by surveying emerging computational and experimental approaches that will provide further insights into the biology of RTK co-activation and deliver new developments in effective cancer therapies. PMID:27452454

  12. Solving Optimal Control Problems by Exploiting Inherent Dynamical Systems Structures

    NASA Astrophysics Data System (ADS)

    Flaßkamp, Kathrin; Ober-Blöbaum, Sina; Kobilarov, Marin

    2012-08-01

    Computing globally efficient solutions is a major challenge in optimal control of nonlinear dynamical systems. This work proposes a method combining local optimization and motion planning techniques based on exploiting inherent dynamical systems structures, such as symmetries and invariant manifolds. Prior to the optimal control, the dynamical system is analyzed for structural properties that can be used to compute pieces of trajectories that are stored in a motion planning library. In the context of mechanical systems, these motion planning candidates, termed primitives, are given by relative equilibria induced by symmetries and motions on stable or unstable manifolds of e.g. fixed points in the natural dynamics. The existence of controlled relative equilibria is studied through Lagrangian mechanics and symmetry reduction techniques. The proposed framework can be used to solve boundary value problems by performing a search in the space of sequences of motion primitives connected using optimized maneuvers. The optimal sequence can be used as an admissible initial guess for a post-optimization. The approach is illustrated by two numerical examples, the single and the double spherical pendula, which demonstrates its benefit compared to standard local optimization techniques.

  13. In situ exploitation of deep set porphyry ores

    SciTech Connect

    Hard, R.A.; Harvey, W.W.; Lingane, P.J.; Park, W.C.; Redman, M.J.

    1981-09-29

    Disclosed is a method of economically exploiting deep set porphyry ore bodies of the type containing metal values such as sulfidic copper, nickel, or uranium minerals and minerals capable of absorbing copper, uranium, and nickel ions. The method involves establishing communication with the ore body through access and recovery wells and passing fluids sequentially therethrough. If necessary, thief zones of as low as 25 to 50 md in igneous rock of 1 to 5 md are prevented from distorting flow, by the injection of a polymeric solution of macromolecules with molecular weights of the order of 5 million along the entire wellbore, the higher permeability zones initially accepting the majority of the flow and being impaired at a much faster rate than the less permeable zones. In a first stage, the permeability of the leaching interval is stimulated as an ammoniated solution of sodium, potassium, or ammonium nitrate or chloride contacts calcium containing minerals to promote ion exchange, resulting in clay contraction or calcium carbonate dissolution. In a second stage, the leaching interval is primed as calcium ion is displaced with an aqueous solution of ammonium salt, a calcium sulfate scale inhibitor, and oxygen gas. In a third stage, a two-phase lixiviant comprising entrained oxygen containing bubbles and an ammoniacal leach liquor having a pH less than 10.5 and less than 1.0 mole/liter ammonia is passed through the leaching interval to solubilize copper, nickel, uranium, and other metal values.

  14. A legal market in organs: the problem of exploitation.

    PubMed

    Greasley, Kate

    2014-01-01

    The article considers the objection to a commercial market in living donor organs for transplantation on the ground that such a market would be exploitative of the vendors. It examines a key challenge to that objection, to the effect that denying poor people the option to sell an organ is to withhold from them the best that a bad situation has to offer. The article casts serious doubt on this attempt at justifying an organ market, and its philosophical underpinning. Drawing, in part, from the catalogued consequences of a thriving kidney market in some parts of India, it is argued that the justification relies on conditions which are extremely unlikely to obtain, even in a regulated donor market: that organ selling meaningfully improves the material situation of the organ vendor. Far from being axiomatic, both logic and the extant empirical evidence point towards the unlikelihood of such an upshot. Finally, the article considers a few conventional counter-arguments in favour of a permissive stance on organ sales.

  15. Polar Lunar Regions: Exploiting Natural and Augmented Thermal Environments

    NASA Technical Reports Server (NTRS)

    Brannon, David; Ryan, Robert E.; Underwood, Lauren W.; Russell, Kristen

    2010-01-01

    In the polar regions of the Moon, some areas within craters are permanently shadowed from solar illumination and can drop to temperatures of 100 K or lower. These sites may serve as cold traps, capturing ice and other volatile compounds, possibly for eons. Interestingly, ice stored in these locations could potentially alter how lunar exploration is conducted. Within craters inside craters (double-shaded craters) that are shaded from thermal re-radiation and from solar illuminated regions, even colder regions should exist and, in many cases, temperatures in these regions never exceed 50 K. Working in these harsh environments with existing conventional systems, exploration or mining activities could be quite daunting and challenging. However, if the unique characteristics of these environments were exploited, the power, weight, and total mass that is required to be carried from the Earth to the Moon for lunar exploration and research would be substantially reduced. In theory, by minimizing the heat transfer between an object and the lunar surface, temperatures near absolute zero can be produced. In a single or double-shaded crater, if the object was isolated from the variety of thermal sources and was allowed to radiatively cool to space, the achievable temperature would be limited by the 3 K cosmic background and the anomalous solar wind that can strike the object being cooled. Our analysis shows that under many circumstances, with some simple thermal radiation shielding, it is possible to establish environments with temperatures of several degrees Kelvin.

  16. Exploitation of complement regulatory proteins by Borrelia and Francisella.

    PubMed

    Madar, Marian; Bencurova, Elena; Mlynarcik, Patrik; Almeida, André M; Soares, Renata; Bhide, Katarina; Pulzova, Lucia; Kovac, Andrej; Coelho, Ana V; Bhide, Mangesh

    2015-06-01

    Pathogens have developed sophisticated mechanisms of complement evasion such as binding to the host complement regulatory proteins (CRPs) on their surface or expression of CRP mimicking molecules. The ability of pathogens to evade the complement system has been correlated with pathogenesis and host selectivity. Hitherto, little work has been undertaken to determine whether Borrelia and Francisella exploit various CRPs to block complement attack. Seventeen Borrelia (twelve species) and six Francisella (three subspecies) strains were used to assess their ability to bind human, sheep and cattle CRPs or mimic membrane associated complement regulators. A series of experiments including affinity ligand binding experiments, pull-down assays and mass spectrometry based protein identification, revealed an array of CRP binding proteins of Borrelia and Francisella. Unlike Francisella, Borrelia strains were able to bind multiple human CRPs. Three strains of Borrelia (SKT-4, SKT-2 and HO14) showed the presence of a human CD46-homologous motif, indicating their ability to possess putative human CD46 mimicking molecules. Similarly, five strains of Borrelia and two strains of Francisella may have surface proteins with human CD59-homologous motifs. Among ovine and bovine CRPs, the only CRP bound by Francisella (LVS, Tul4 strain) was vitronectin, while ovine C4BP, ovine factor H and bovine factor H were bound to Borrelia strains SKT-2, DN127 and Co53. This study presents an array of proteins of Borrelia and Francisella that bind CRPs or may mimic membrane-CRPs, thus enabling multiphasic complement evasion strategies of these pathogens.

  17. Exploiting macrophages as targeted carrier to guide nanoparticles into glioma

    PubMed Central

    Pang, Liang; Qin, Jing; Han, Limei; Zhao, Wenjie; Liang, Jianming; Xie, Zhongyi; Yang, Pei; Wang, Jianxin

    2016-01-01

    The restriction of anti-cancer drugs entry to tumor sites in the brain is a major impediment to the development of new strategies for the treatment of glioma. Based on the finding that macrophages possess an intrinsic homing property enabling them to migrate to tumor sites across the endothelial barriers in response to the excretion of cytokines/chemokines in the diseased tissues, we exploited macrophages as ‘Trojan horses’ to carry drug-loading nanoparticles (NPs), pass through barriers, and offload them into brain tumor sites. Anticancer drugs were encapsulated in nanoparticles to avoid their damage to the cells. Drug loading NPs was then incubated with RAW264.7 cells in vitro to prepare macrophage-NPs (M-NPs). The release of NPs from M-NPs was very slow in medium of DMEM and 10% FBS and significantly accelerated when LPS and IFN-γ were added to mimic tumor inflammation microenvironment. The viability of macrophages was not affected when the concentration of doxorubicin lower than 25 μg/ml. The improvement of cellular uptake and penetration into the core of glioma spheroids of M-NPs compared with NPs was verified in in vitro studies. The tumor-targeting efficiency of NPs was also significantly enhanced after loading into macrophages in nude mice bearing intracranial U87 glioma. Our results provided great potential of macrophages as an active biocarrier to deliver anticancer drugs to the tumor sites in the brain and improve therapeutic effects of glioma. PMID:27213597

  18. Exploiting Data Parallelism in the Image Content Engine

    SciTech Connect

    Miller, W M; Garlick, J E; Weinert, G F; Abdulla, G M

    2006-03-09

    The Image Content Engine (ICE) is a framework of software and underlying mathematical and physical models that enable scientists and analysts to extract features from Terabytes of imagery and search the extracted features for content relevant to their problem domain. The ICE team has developed a set of tools for feature extraction and analysis of image data, primarily based on the image content. The scale and volume of imagery that must be searched presents a formidable computation and data bandwidth challenge, and a search of moderate to large scale imagery quickly becomes intractable without exploiting high degrees of data parallelism in the feature extraction engine. In this paper we describe the software and hardware architecture developed to build a data parallel processing engine for ICE. We discuss our highly tunable parallel process and job scheduling subsystem, remote procedure invocation, parallel I/O strategy, and our experience in running ICE on a 16 node, 32 processing element (CPU) Linux Cluster. We present performance and benchmark results, and describe how we obtain excellent speedup for the imagery searches in our test-bed prototype.

  19. Exploiting budding yeast natural variation for industrial processes.

    PubMed

    Cubillos, Francisco A

    2016-11-01

    For the last two decades, the natural variation of the yeast Saccharomyces cerevisiae has been massively exploited with the aim of understanding ecological and evolutionary processes. As a result, many new genetic variants have been uncovered, providing a large catalogue of alleles underlying complex traits. These alleles represent a rich genetic resource with the potential to provide new strains that can cope with the growing demands of industrial fermentation processes. When surveyed in detail, several of these variants have proven useful in wine and beer industries by improving nitrogen utilisation, fermentation kinetics, ethanol production, sulphite resistance and aroma production. Here, I illustrate how allele-specific expression and polymorphisms within the coding region of GDB1 underlie fermentation kinetic differences in synthetic wine must. Nevertheless, the genetic basis of how GDB1 variants and other natural alleles interact in foreign genetic backgrounds remains unclear. Further studies in large sets of strains, recombinant hybrids and multiple parental pairs will broaden our knowledge of the molecular and genetic basis of trait adaptation for utilisation in applied and industrial processes.

  20. Improving industrial yeast strains: exploiting natural and artificial diversity

    PubMed Central

    Steensels, Jan; Snoek, Tim; Meersman, Esther; Nicolino, Martina Picca; Voordeckers, Karin; Verstrepen, Kevin J

    2014-01-01

    Yeasts have been used for thousands of years to make fermented foods and beverages, such as beer, wine, sake, and bread. However, the choice for a particular yeast strain or species for a specific industrial application is often based on historical, rather than scientific grounds. Moreover, new biotechnological yeast applications, such as the production of second-generation biofuels, confront yeast with environments and challenges that differ from those encountered in traditional food fermentations. Together, this implies that there are interesting opportunities to isolate or generate yeast variants that perform better than the currently used strains. Here, we discuss the different strategies of strain selection and improvement available for both conventional and nonconventional yeasts. Exploiting the existing natural diversity and using techniques such as mutagenesis, protoplast fusion, breeding, genome shuffling and directed evolution to generate artificial diversity, or the use of genetic modification strategies to alter traits in a more targeted way, have led to the selection of superior industrial yeasts. Furthermore, recent technological advances allowed the development of high-throughput techniques, such as ‘global transcription machinery engineering’ (gTME), to induce genetic variation, providing a new source of yeast genetic diversity. PMID:24724938

  1. Bats track and exploit changes in insect pest populations.

    PubMed

    McCracken, Gary F; Westbrook, John K; Brown, Veronica A; Eldridge, Melanie; Federico, Paula; Kunz, Thomas H

    2012-01-01

    The role of bats or any generalist predator in suppressing prey populations depends on the predator's ability to track and exploit available prey. Using a qPCR fecal DNA assay, we document significant association between numbers of Brazilian free-tailed bats (Tadarida brasiliensis) consuming corn earworm (CEW) moths (Helicoverpa zea) and seasonal fluctuations in CEW populations. This result is consistent with earlier research linking the bats' diet to patterns of migration, abundance, and crop infestation by important insect pests. Here we confirm opportunistic feeding on one of the world's most destructive insects and support model estimates of the bats' ecosystem services. Regression analysis of CEW consumption versus the moth's abundance at four insect trapping sites further indicates that bats track local abundance of CEW within the regional landscape. Estimates of CEW gene copies in the feces of bats are not associated with seasonal or local patterns of CEW abundance, and results of captive feeding experiments indicate that our qPCR assay does not provide a direct measure of numbers or biomass of prey consumed. Our results support growing evidence for the role of generalist predators, and bats specifically, as agents for biological control and speak to the value of conserving indigenous generalist predators.

  2. Methods for spectral image analysis by exploiting spatial simplicity

    DOEpatents

    Keenan, Michael R.

    2010-11-23

    Several full-spectrum imaging techniques have been introduced in recent years that promise to provide rapid and comprehensive chemical characterization of complex samples. One of the remaining obstacles to adopting these techniques for routine use is the difficulty of reducing the vast quantities of raw spectral data to meaningful chemical information. Multivariate factor analysis techniques, such as Principal Component Analysis and Alternating Least Squares-based Multivariate Curve Resolution, have proven effective for extracting the essential chemical information from high dimensional spectral image data sets into a limited number of components that describe the spectral characteristics and spatial distributions of the chemical species comprising the sample. There are many cases, however, in which those constraints are not effective and where alternative approaches may provide new analytical insights. For many cases of practical importance, imaged samples are "simple" in the sense that they consist of relatively discrete chemical phases. That is, at any given location, only one or a few of the chemical species comprising the entire sample have non-zero concentrations. The methods of spectral image analysis of the present invention exploit this simplicity in the spatial domain to make the resulting factor models more realistic. Therefore, more physically accurate and interpretable spectral and abundance components can be extracted from spectral images that have spatially simple structure.

  3. Methods for spectral image analysis by exploiting spatial simplicity

    DOEpatents

    Keenan, Michael R.

    2010-05-25

    Several full-spectrum imaging techniques have been introduced in recent years that promise to provide rapid and comprehensive chemical characterization of complex samples. One of the remaining obstacles to adopting these techniques for routine use is the difficulty of reducing the vast quantities of raw spectral data to meaningful chemical information. Multivariate factor analysis techniques, such as Principal Component Analysis and Alternating Least Squares-based Multivariate Curve Resolution, have proven effective for extracting the essential chemical information from high dimensional spectral image data sets into a limited number of components that describe the spectral characteristics and spatial distributions of the chemical species comprising the sample. There are many cases, however, in which those constraints are not effective and where alternative approaches may provide new analytical insights. For many cases of practical importance, imaged samples are "simple" in the sense that they consist of relatively discrete chemical phases. That is, at any given location, only one or a few of the chemical species comprising the entire sample have non-zero concentrations. The methods of spectral image analysis of the present invention exploit this simplicity in the spatial domain to make the resulting factor models more realistic. Therefore, more physically accurate and interpretable spectral and abundance components can be extracted from spectral images that have spatially simple structure.

  4. Bacterial multidrug efflux pumps: mechanisms, physiology and pharmacological exploitations.

    PubMed

    Sun, Jingjing; Deng, Ziqing; Yan, Aixin

    2014-10-17

    Multidrug resistance (MDR) refers to the capability of bacterial pathogens to withstand lethal doses of structurally diverse drugs which are capable of eradicating non-resistant strains. MDR has been identified as a major threat to the public health of human being by the World Health Organization (WHO). Among the four general mechanisms that cause antibiotic resistance including target alteration, drug inactivation, decreased permeability and increased efflux, drug extrusion by the multidrug efflux pumps serves as an important mechanism of MDR. Efflux pumps not only can expel a broad range of antibiotics owing to their poly-substrate specificity, but also drive the acquisition of additional resistance mechanisms by lowering intracellular antibiotic concentration and promoting mutation accumulation. Over-expression of multidrug efflux pumps have been increasingly found to be associated with clinically relevant drug resistance. On the other hand, accumulating evidence has suggested that efflux pumps also have physiological functions in bacteria and their expression is subject tight regulation in response to various of environmental and physiological signals. A comprehensive understanding of the mechanisms of drug extrusion, and regulation and physiological functions of efflux pumps is essential for the development of anti-resistance interventions. In this review, we summarize the development of these research areas in the recent decades and present the pharmacological exploitation of efflux pump inhibitors as a promising anti-drug resistance intervention.

  5. Parallel Exploitation of Diverse Host Nutrients Enhances Salmonella Virulence

    PubMed Central

    Steeb, Benjamin; Claudi, Beatrice; Burton, Neil A.; Tienz, Petra; Schmidt, Alexander; Farhan, Hesso; Mazé, Alain; Bumann, Dirk

    2013-01-01

    Pathogen access to host nutrients in infected tissues is fundamental for pathogen growth and virulence, disease progression, and infection control. However, our understanding of this crucial process is still rather limited because of experimental and conceptual challenges. Here, we used proteomics, microbial genetics, competitive infections, and computational approaches to obtain a comprehensive overview of Salmonella nutrition and growth in a mouse typhoid fever model. The data revealed that Salmonella accessed an unexpectedly diverse set of at least 31 different host nutrients in infected tissues but the individual nutrients were available in only scarce amounts. Salmonella adapted to this situation by expressing versatile catabolic pathways to simultaneously exploit multiple host nutrients. A genome-scale computational model of Salmonella in vivo metabolism based on these data was fully consistent with independent large-scale experimental data on Salmonella enzyme quantities, and correctly predicted 92% of 738 reported experimental mutant virulence phenotypes, suggesting that our analysis provided a comprehensive overview of host nutrient supply, Salmonella metabolism, and Salmonella growth during infection. Comparison of metabolic networks of other pathogens suggested that complex host/pathogen nutritional interfaces are a common feature underlying many infectious diseases. PMID:23633950

  6. Research trends in wireless visual sensor networks when exploiting prioritization.

    PubMed

    Costa, Daniel G; Guedes, Luiz Affonso; Vasques, Francisco; Portugal, Paulo

    2015-01-15

    The development of wireless sensor networks for control and monitoring functions has created a vibrant investigation scenario, where many critical topics, such as communication efficiency and energy consumption, have been investigated in the past few years. However, when sensors are endowed with low-power cameras for visual monitoring, a new scope of challenges is raised, demanding new research efforts. In this context, the resource-constrained nature of sensor nodes has demanded the use of prioritization approaches as a practical mechanism to lower the transmission burden of visual data over wireless sensor networks. Many works in recent years have considered local-level prioritization parameters to enhance the overall performance of those networks, but global-level policies can potentially achieve better results in terms of visual monitoring efficiency. In this paper, we make a broad review of some recent works on priority-based optimizations in wireless visual sensor networks. Moreover, we envisage some research trends when exploiting prioritization, potentially fostering the development of promising optimizations for wireless sensor networks composed of visual sensors.

  7. Murine Cytomegalovirus Exploits Olfaction To Enter New Hosts

    PubMed Central

    Farrell, Helen E.; Lawler, Clara; Tan, Cindy S. E.; MacDonald, Kate; Bruce, Kimberley; Mach, Michael; Davis-Poynter, Nick

    2016-01-01

    ABSTRACT   Viruses transmit via the environmental and social interactions of their hosts. Herpesviruses have colonized mammals since their earliest origins, suggesting that they exploit ancient, common pathways. Cytomegaloviruses (CMVs) are assumed to enter new hosts orally, but no site has been identified. We show by live imaging that murine CMV (MCMV) infects nasally rather than orally, both after experimental virus uptake and during natural transmission. Replication-deficient virions revealed the primary target as olfactory neurons. Local, nasal replication by wild-type MCMV was not extensive, but there was rapid systemic spread, associated with macrophage infection. A long-term, transmissible infection was then maintained in the salivary glands. The viral m131/m129 chemokine homolog, which influences tropism, promoted salivary gland colonization after nasal entry but was not required for entry per se. The capacity of MCMV to transmit via olfaction, together with previous demonstrations of experimental olfactory infection by murid herpesvirus 4 (MuHV-4) and herpes simplex virus 1 (HSV-1), suggest that this is a common, conserved route of mammalian herpesvirus entry. PMID:27118588

  8. Use Hierarchical Storage and Analysis to Exploit Intrinsic Parallelism

    NASA Astrophysics Data System (ADS)

    Zender, C. S.; Wang, W.; Vicente, P.

    2013-12-01

    Big Data is an ugly name for the scientific opportunities and challenges created by the growing wealth of geoscience data. How to weave large, disparate datasets together to best reveal their underlying properties, to exploit their strengths and minimize their weaknesses, to continually aggregate more information than the world knew yesterday and less than we will learn tomorrow? Data analytics techniques (statistics, data mining, machine learning, etc.) can accelerate pattern recognition and discovery. However, often researchers must, prior to analysis, organize multiple related datasets into a coherent framework. Hierarchical organization permits entire dataset to be stored in nested groups that reflect their intrinsic relationships and similarities. Hierarchical data can be simpler and faster to analyze by coding operators to automatically parallelize processes over isomorphic storage units, i.e., groups. The newest generation of netCDF Operators (NCO) embody this hierarchical approach, while still supporting traditional analysis approaches. We will use NCO to demonstrate the trade-offs involved in processing a prototypical Big Data application (analysis of CMIP5 datasets) using hierarchical and traditional analysis approaches.

  9. Research Trends in Wireless Visual Sensor Networks When Exploiting Prioritization

    PubMed Central

    Costa, Daniel G.; Guedes, Luiz Affonso; Vasques, Francisco; Portugal, Paulo

    2015-01-01

    The development of wireless sensor networks for control and monitoring functions has created a vibrant investigation scenario, where many critical topics, such as communication efficiency and energy consumption, have been investigated in the past few years. However, when sensors are endowed with low-power cameras for visual monitoring, a new scope of challenges is raised, demanding new research efforts. In this context, the resource-constrained nature of sensor nodes has demanded the use of prioritization approaches as a practical mechanism to lower the transmission burden of visual data over wireless sensor networks. Many works in recent years have considered local-level prioritization parameters to enhance the overall performance of those networks, but global-level policies can potentially achieve better results in terms of visual monitoring efficiency. In this paper, we make a broad review of some recent works on priority-based optimizations in wireless visual sensor networks. Moreover, we envisage some research trends when exploiting prioritization, potentially fostering the development of promising optimizations for wireless sensor networks composed of visual sensors. PMID:25599425

  10. The business of exploiting induced pluripotent stem cells.

    PubMed

    Prescott, Catherine

    2011-08-12

    Induced pluripotent stem cells (iPS cells) can be exploited for both research and clinical applications. The first part of this review seeks to provide an understanding of the financial drivers and key elements of a successful business strategy that underpin a company focused on developing iPS-related products and services targeted at the research market. The latter part of the review highlights some of the reasons as to why the reprogramming of somatic cells is currently being used to develop cell-based models to screen for small molecules with drug-like properties rather than to develop cell-based regenerative medicines per se. The latter may be used to repair or replace a patient's damaged cells and thereby have the potential to 'cure' a disease and, in doing so, prevent or delay the onset of associated medical conditions. However, the cost of an expensive regenerative medicine and time to accrue any benefit linked to a decrease in co-morbidity expenditure may not outweigh the benefit for a healthcare community that has finite resources. The implications of this are discussed together with evidence that the UK National Institute for Health and Clinical Excellence (NICE) and the National Health Service (NHS) have established a precedent for a cost-sharing strategy with the pharmaceutical industry.

  11. Resonant diphoton phenomenology simplified

    NASA Astrophysics Data System (ADS)

    Panico, Giuliano; Vecchi, Luca; Wulzer, Andrea

    2016-06-01

    A framework is proposed to describe resonant diphoton phenomenology at hadron colliders in full generality. It can be employed for a comprehensive model-independent interpretation of the experimental data. Within the general framework, few benchmark scenarios are defined as representative of the various phenomenological options and/or of motivated new physics scenarios. Their usage is illustrated by performing a characterization of the 750 GeV excess, based on a recast of available experimental results.

  12. Tandem resonator reflectance modulator

    DOEpatents

    Fritz, I.J.; Wendt, J.R.

    1994-09-06

    A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors. 8 figs.

  13. Tandem resonator reflectance modulator

    DOEpatents

    Fritz, Ian J.; Wendt, Joel R.

    1994-01-01

    A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors.

  14. Cross resonant optical antenna.

    PubMed

    Biagioni, P; Huang, J S; Duò, L; Finazzi, M; Hecht, B

    2009-06-26

    We propose a novel cross resonant optical antenna consisting of two perpendicular nanosized gold dipole antennas with a common feed gap. We demonstrate that the cross antenna is able to convert propagating fields of any polarization state into correspondingly polarized, localized, and enhanced fields and vice versa. The cross antenna structure therefore opens the road towards the control of light-matter interactions based on polarized light as well as the analysis of polarized fields on the nanometer scale.

  15. Linear Resonance Cooler.

    DTIC Science & Technology

    1985-04-01

    for a Stirling cycle cryocooler . 26 * .*o .. * COMPRESSOR MOTOR FORCE VERSUS ROTOR AXIAL POSITION COMPRESSOR P-V DIAGRAM *COMPRESSOR MOTOR COMPRESSOR...potential. However, the limited test program has demonstrated the application of linear motor drive technology to a Stirling cycle cryocooler design. L...Ace-ss Ion& For flTIC TAB - TABLE OF CONTENTS TITLE IPAGE - 2. DETAILED DESIGN OF LINEAR RESONANCE CRYOCOOLER ......... 3 2.2 Expander

  16. Higher-order resonances in a Stark decelerator

    SciTech Connect

    Meerakker, Sebastiaan Y.T. van de; Bethlem, Hendrick L.; Vanhaecke, Nicolas; Meijer, Gerard

    2005-05-15

    The motion of polar molecules can be controlled by time-varying inhomogeneous electric fields. In a Stark decelerator, this is exploited to select a fraction of a molecular beam that is accelerated, transported, or decelerated. Phase stability ensures that the selected bunch of molecules is kept together throughout the deceleration process. In this paper an extended description of phase stability in a Stark decelerator is given, including higher-order effects. This analysis predicts a wide variety of resonances that originate from the spatial and temporal periodicity of the electric fields. These resonances are experimentally observed using a beam of OH ({sup 2}{pi}{sub 3/2},v=0,J=3/2) radicals passing through a Stark decelerator.

  17. Coupled-resonator-induced-transparency concept for wavelength routing applications.

    PubMed

    Mancinelli, M; Guider, R; Bettotti, P; Masi, M; Vanacharla, M R; Pavesi, L

    2011-06-20

    The presence of coupled resonators induced transparency (CRIT) effects in side-coupled integrated spaced sequence of resonators (SCISSOR) of different radii has been studied. By controlling the rings radii and their center to center distance, it is possible to form transmission channels within the SCISSOR stop-band. Two different methods to exploit the CRIT effect in add/drop filters are proposed. Their performances, e. g. linewidth, crosstalk and losses, are examined also for random variations in the structural parameters. Finally, few examples of high performances mux/demux structures and 2 × 2 routers based on these modified SCISSOR are presented. CRIT based SCISSOR optical devices are particularly promising for ultra-dense wavelength division multiplexing applications.

  18. Investigating the Pygmy Dipole Resonance Using β Decay

    NASA Astrophysics Data System (ADS)

    Scheck, M.; Mishev, S.; Ponomarev, V. Yu.; Chapman, R.; Gaffney, L. P.; Gregor, E. T.; Pietralla, N.; Spagnoletti, P.; Savran, D.; Simpson, G. S.

    2016-04-01

    In this contribution it is explored whether γ -ray spectroscopy following β decay with high Q values from mother nuclei with low ground-state spin can be exploited as a probe for the pygmy dipole resonance. The suitability of this approach is demonstrated by a comparison between data from photon scattering, 136Xe (γ ,γ') , and 136I [J0π=(1-)]→136Xe* β -decay data. It is demonstrated that β decay populates 1- levels associated with the pygmy dipole resonance, but only a fraction of those. The complementary insight into the wave functions probed by β decay is elucidated by calculations within the quasiparticle phonon model. It is demonstrated that β decay dominantly populates complex configurations, which are only weakly excited in inelastic scattering experiments.

  19. RESONATOR PARTICLE SEPARATOR

    DOEpatents

    Blewett, J.P.

    1962-01-01

    A wave guide resonator structure is described for use in separating particles of equal momentum but differing in mass and having energies exceeding one billion electron volts. The particles are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high-energy accelerator. In this wave guide construction, the particles undergo preferential deflection as a result of the presence of an electric field. The boundary conditions established in the resonator are such as to eliminate an interfering magnetic component, and to otherwise phase the electric field to obtain a traveling wave such as one which moves at the same speed as the unwanted particle. The latter undergoes continuous deflection over the whole length of the device and is, therefore, eliminated while the wanted particle is deflected in opposite directions over the length of the resonator and is thus able to enter an exit aperture. (AEC)

  20. Resonant non-gaussianity

    SciTech Connect

    Flauger, Raphael; Pajer, Enrico E-mail: ep295@cornell.edu

    2011-01-01

    We provide a derivation from first principles of the primordial bispectrum of scalar perturbations produced during inflation driven by a canonically normalized scalar field whose potential exhibits small sinusoidal modulations. A potential of this type has been derived in a class of string theory models of inflation based on axion monodromy. We use this model as a concrete example, but we present our derivations and results for a general slow-roll potential with superimposed modulations. We show analytically that a resonance between the oscillations of the background and the oscillations of the fluctuations is responsible for the production of an observably large non-Gaussian signal. We provide an explicit expression for the shape of this resonant non-Gaussianity. We show that there is essentially no overlap between this shape and the local, equilateral, and orthogonal shapes, and we stress that resonant non-Gaussianity is not captured by the simplest version of the effective field theory of inflation. We hope our analytic expression will be useful to further observationally constrain this class of models.

  1. Resonant Alfven Wave Excitation

    NASA Astrophysics Data System (ADS)

    Hameiri, Eliezer

    1999-11-01

    Much of the theory of the Alfven wave resonance phenomenon was developed for a tokamak configuration where the magnetic field winds around the torus without entering the boundary. Thus, boundary conditions did not have to be considered.( J. Tataronis and W. Grossmann, Z. Phys. 261), 203 (1973). In most space plasma situations such as the magnetosphere or the Sun, as well as in the scrape-off layer of a divertor tokamak, this is not the case. When boundary conditions are considered, it is generally assumed for simplicity that the boundary is perfectly conducting, which implies that the Alfven wave bounce frequencies are real and the resonance phenomenon can be detected by some singularity in the equations. The nature of the singularity is usually described in terms of a Frobenius series.( A.N. Wright and M.J. Thompson, Phys. Plamsas 1), 691 (1994). In this work we consider resistive boundaries, which imply that the fast wave eigenfrequency is real, but the Alfven frequency is not. Thus, there is no exact resonance and no singularity in the equations. The solution of the problem is carried out asymptotically by finding an exact Laplace integral representation for the solution and then matching various regions. The energy transferred to the Alfven wave appears to be rather small.

  2. Resonance Raman spectroscopy.

    PubMed

    Robert, Bruno

    2009-01-01

    Resonance Raman spectroscopy may yield precise information on the conformation of, and on the interactions assumed by, the chromophores involved in the first steps of the photosynthetic process, whether isolated in solvents, embedded in soluble or membrane proteins, or, as shown recently, in vivo. By making use of this technique, it is possible, for instance, to relate the electronic properties of these molecules to their structure and/or the physical properties of their environment, or to determine subtle changes of their conformation associated with regulatory processes. After a short introduction to the physical principles that govern resonance Raman spectroscopy, the information content of resonance Raman spectra of chlorophyll and carotenoid molecules is described in this review, together with the experiments which helped in determining which structural parameter each Raman band is sensitive to. A selection of applications of this technique is then presented, in order to give a fair and precise idea of which type of information can be obtained from its use in the field of photosynthesis.

  3. Injection-controlled laser resonator

    DOEpatents

    Chang, Jim J.

    1995-07-18

    A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality.

  4. Aberration correction of unstable resonators

    NASA Technical Reports Server (NTRS)

    Lang, Robert J. (Inventor)

    1994-01-01

    Construction of aspheric reflectors for unstable resonator lasers to provide an arbitrary laser mode inside the resonator to correct aberrations of an output beam by the construction of the shape of an end reflector opposite the output reflector of the resonator cavity, such as aberrations resulting from refraction of a beam exiting the solid of the resonator having an index of refraction greater than 1 or to produce an aberration in the output beam that will precisely compensate for the aberration of an optical train into which the resonator beam is coupled.

  5. Injection-controlled laser resonator

    DOEpatents

    Chang, J.J.

    1995-07-18

    A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality. 5 figs.

  6. Persistence, resistance, resonance

    NASA Astrophysics Data System (ADS)

    Tsadka, Maayan

    Sound cannot travel in a vacuum, physically or socially. The ways in which sound operates are a result of acoustic properties, and the ways by which it is considered to be music are a result of social constructions. Therefore, music is always political, regardless of its content: the way it is performed and composed; the choice of instrumentation, notation, tuning; the medium of its distribution; its inherent hierarchy and power dynamics, and more. My compositional praxis makes me less interested in defining a relationship between music and politics than I am in erasing---or at least blurring---the borders between them. In this paper I discuss the aesthetics of resonance and echo in their metaphorical, physical, social, and musical manifestations. Also discussed is a political aesthetic of resonance, manifested through protest chants. I transcribe and analyze common protest chants from around the world, categorizing and unifying them as universal crowd-mobilizing rhythms. These ideas are explored musically in three pieces. Sumud: Rhetoric of Resistance in Three Movements, for two pianos and two percussion players, is a musical interpretation of the political/social concept of sumud, an Arabic word that literally means "steadfastness" and represents Palestinian non-violent resistance. The piece is based on common protest rhythms and uses the acoustic properties inherent to the instruments. The second piece, Three Piano Studies, extends some of the musical ideas and techniques used in Sumud, and explores the acoustic properties and resonance of the piano. The final set of pieces is part of my Critical Mess Music Project. These are site-specific musical works that attempt to blur the boundaries between audience, performers and composer, in part by including people without traditional musical training in the process of music making. These pieces use the natural structure and resonance of an environment, in this case, locations on the UCSC campus, and offer an active

  7. Exploiting node mobility for energy optimization in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    El-Moukaddem, Fatme Mohammad

    Wireless Sensor Networks (WSNs) have become increasingly available for data-intensive applications such as micro-climate monitoring, precision agriculture, and audio/video surveillance. A key challenge faced by data-intensive WSNs is to transmit the sheer amount of data generated within an application's lifetime to the base station despite the fact that sensor nodes have limited power supplies such as batteries or small solar panels. The availability of numerous low-cost robotic units (e.g. Robomote and Khepera) has made it possible to construct sensor networks consisting of mobile sensor nodes. It has been shown that the controlled mobility offered by mobile sensors can be exploited to improve the energy efficiency of a network. In this thesis, we propose schemes that use mobile sensor nodes to reduce the energy consumption of data-intensive WSNs. Our approaches differ from previous work in two main aspects. First, our approaches do not require complex motion planning of mobile nodes, and hence can be implemented on a number of low-cost mobile sensor platforms. Second, we integrate the energy consumption due to both mobility and wireless communications into a holistic optimization framework. We consider three problems arising from the limited energy in the sensor nodes. In the first problem, the network consists of mostly static nodes and contains only a few mobile nodes. In the second and third problems, we assume essentially that all nodes in the WSN are mobile. We first study a new problem called max-data mobile relay configuration (MMRC ) that finds the positions of a set of mobile sensors, referred to as relays, that maximize the total amount of data gathered by the network during its lifetime. We show that the MMRC problem is surprisingly complex even for a trivial network topology due to the joint consideration of the energy consumption of both wireless communication and mechanical locomotion. We present optimal MMRC algorithms and practical distributed

  8. Exploitation of hemicellulose, cellulose and lignin from Hesperaloe funifera.

    PubMed

    Sánchez, R; Rodríguez, A; García, J C; Rosal, A; Jiménez, L

    2011-01-01

    This work seeks the integral use of all major components of Hesperaloe funifera, separating hemicelluose by hydrothermal treatments; cellulose by pulping processes; and exploitation of lignin of pulping liquor by pyrolysis and gasification processes. By using sulfuric acid in the hydrothermal treatment (150-190 °C, 0-20 min after reaching operating temperature, 6-10 liquid/solid ratio, 0.1-0.5% sulfuric acid), the glucose and xylose of liquid fraction increase from 1.5% to 5.9%, and 4.0% to 12.4%, respectively; the yields of solid fraction decrease from 91.6% to 79.5%, and the lignin content increase from 23% to 32%. Pulps and paper sheets obtained from solid fractions hydrothermal treatments and from raw material pulped with diethanolamine, are worse than those obtained with soda-anthraquinone (Yield 57.8%; kappa number 24.9; Viscosity 711 mL/g; Brightness 54.8%; Tensile index 73.6 Nm/g; Stretch 2.84%; Burst index 6.13 kN/g and Tear index 1.69 mNm2/g). By acidification (pH 6) of soda pulping liquor it separate lignin-rich solids, which by pyrolysis gave a gas containing 1.13% H2, 31.79% CO and 1.86% CH4 by weight. Gasification of the same sample provided a gas containing 0.18% H2, 24.50% CO and 17.75% CH4.

  9. The role of space in the exploitation of resources.

    PubMed

    Kang, Y; Lanchier, N

    2012-01-01

    In order to understand the role of space in ecological communities where each species produces a certain type of resource and has varying abilities to exploit the resources produced by its own species and by the other species, we carry out a comparative study of an interacting particle system and its mean-field approximation. For a wide range of parameter values, we show both analytically and numerically that the spatial model results in predictions that significantly differ from its nonspatial counterpart, indicating that the use of the mean-field approach to describe the evolution of communities in which individuals only interact locally is invalid. In two-species communities, the disagreements between the models appear either when both species compete by producing resources that are more beneficial for their own species or when both species cooperate by producing resources that are more beneficial for the other species. In particular, while both species coexist if and only if they cooperate in the mean-field approximation, the inclusion of space in the form of local interactions may prevent coexistence even in cooperative communities. Introducing additional species, cooperation is no longer the only mechanism that promotes coexistence. We prove that, in three-species communities, coexistence results either from a global cooperative behavior, or from rock-paper-scissors type interactions, or from a mixture of these dynamics, which excludes in particular all cases in which two species compete. Finally, and more importantly, we show numerically that the inclusion of space has antagonistic effects on coexistence depending on the mechanism involved, preventing coexistence in the presence of cooperation but promoting coexistence in the presence of rock-paper-scissors interactions. Although these results are partly proved analytically for both models, we also provide somewhat more explicit heuristic arguments to explain the reason why the models result in different

  10. Tunable Optical True-Time Delay Devices Would Exploit EIT

    NASA Technical Reports Server (NTRS)

    Kulikov, Igor; DiDomenico, Leo; Lee, Hwang

    2004-01-01

    Tunable optical true-time delay devices that would exploit electromagnetically induced transparency (EIT) have been proposed. Relative to prior true-time delay devices (for example, devices based on ferroelectric and ferromagnetic materials) and electronically controlled phase shifters, the proposed devices would offer much greater bandwidths. In a typical envisioned application, an optical pulse would be modulated with an ultra-wideband radio-frequency (RF) signal that would convey the information that one seeks to communicate, and it would be required to couple differently delayed replicas of the RF signal to the radiating elements of a phased-array antenna. One or more of the proposed devices would be used to impose the delays and/or generate the delayed replicas of the RF-modulated optical pulse. The beam radiated or received by the antenna would be steered by use of a microprocessor-based control system that would adjust operational parameters of the devices to tune the delays to the required values. EIT is a nonlinear quantum optical interference effect that enables the propagation of light through an initially opaque medium. A suitable medium must have, among other properties, three quantum states (see Figure 1): an excited state (state 3), an upper ground state (state 2), and a lower ground state (state 1). These three states must form a closed system that exhibits no decays to other states in the presence of either or both of two laser beams: (1) a probe beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 1; and (2) a coupling beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 2. The probe beam is the one that is pulsed and modulated with an RF signal.

  11. Exploiting Parallel R in the Cloud with SPRINT

    PubMed Central

    Piotrowski, M.; McGilvary, G.A.; Sloan, T. M.; Mewissen, M.; Lloyd, A.D.; Forster, T.; Mitchell, L.; Ghazal, P.; Hill, J.

    2012-01-01

    Background Advances in DNA Microarray devices and next-generation massively parallel DNA sequencing platforms have led to an exponential growth in data availability but the arising opportunities require adequate computing resources. High Performance Computing (HPC) in the Cloud offers an affordable way of meeting this need. Objectives Bioconductor, a popular tool for high-throughput genomic data analysis, is distributed as add-on modules for the R statistical programming language but R has no native capabilities for exploiting multi-processor architectures. SPRINT is an R package that enables easy access to HPC for genomics researchers. This paper investigates: setting up and running SPRINT-enabled genomic analyses on Amazon’s Elastic Compute Cloud (EC2), the advantages of submitting applications to EC2 from different parts of the world and, if resource underutilization can improve application performance. Methods The SPRINT parallel implementations of correlation, permutation testing, partitioning around medoids and the multi-purpose papply have been benchmarked on data sets of various size on Amazon EC2. Jobs have been submitted from both the UK and Thailand to investigate monetary differences. Results It is possible to obtain good, scalable performance but the level of improvement is dependent upon the nature of algorithm. Resource underutilization can further improve the time to result. End-user’s location impacts on costs due to factors such as local taxation. Conclusions: Although not designed to satisfy HPC requirements, Amazon EC2 and cloud computing in general provides an interesting alternative and provides new possibilities for smaller organisations with limited funds. PMID:23223611

  12. Population diversity and the portfolio effect in an exploited species.

    PubMed

    Schindler, Daniel E; Hilborn, Ray; Chasco, Brandon; Boatright, Christopher P; Quinn, Thomas P; Rogers, Lauren A; Webster, Michael S

    2010-06-03

    One of the most pervasive themes in ecology is that biological diversity stabilizes ecosystem processes and the services they provide to society, a concept that has become a common argument for biodiversity conservation. Species-rich communities are thought to produce more temporally stable ecosystem services because of the complementary or independent dynamics among species that perform similar ecosystem functions. Such variance dampening within communities is referred to as a portfolio effect and is analogous to the effects of asset diversity on the stability of financial portfolios. In ecology, these arguments have focused on the effects of species diversity on ecosystem stability but have not considered the importance of biologically relevant diversity within individual species. Current rates of population extirpation are probably at least three orders of magnitude higher than species extinction rates, so there is a pressing need to clarify how population and life history diversity affect the performance of individual species in providing important ecosystem services. Here we use five decades of data from Oncorhynchus nerka (sockeye salmon) in Bristol Bay, Alaska, to provide the first quantification of portfolio effects that derive from population and life history diversity in an important and heavily exploited species. Variability in annual Bristol Bay salmon returns is 2.2 times lower than it would be if the system consisted of a single homogenous population rather than the several hundred discrete populations it currently consists of. Furthermore, if it were a single homogeneous population, such increased variability would lead to ten times more frequent fisheries closures. Portfolio effects are also evident in watershed food webs, where they stabilize and extend predator access to salmon resources. Our results demonstrate the critical importance of maintaining population diversity for stabilizing ecosystem services and securing the economies and livelihoods

  13. The Use of Intensity Scales In Exploiting Tsunami Historical Databases

    NASA Astrophysics Data System (ADS)

    Barberopoulou, A.; Scheele, F.

    2015-12-01

    Post-disaster assessments for historical tsunami events (>15 years old) are either scarce or contain limited information. In this study, we are assessing ways to examine tsunami impacts by utilizing data from old events, but more importantly we examine how to best utilize information contained in tsunami historical databases, in order to provide meaningful products that describe the impact of the event. As such, a tsunami intensity scale was applied to two historical events that were observed in New Zealand (one local and one distant), in order to utilize the largest possible number of observations in our dataset. This is especially important for countries like New Zealand where the tsunami historical record is short, going back to only the 19th century, and where instrument recordings are only available for the most recent events. We found that despite a number of challenges in using intensities -uncertainties partly due to limitations of historical event data - these data with the help of GIS tools can be used to produce hazard maps and offer an alternative way to exploit tsunami historical records. Most importantly the assignment of intensities at each point of observation allows for utilization of many more observations than if one depends on physical information alone, such as water heights. We hope these results may be used towards developing a well-defined methodology for hazard assessments, and refine our knowledge for past tsunami events for which the tsunami sources are largely unknown, and also for when physical quantities describing the tsunami (e.g. water height, flood depth, run-up) are scarce.

  14. Exploiting Aura OMI Level 2 Data with High Resolution Visualization

    NASA Astrophysics Data System (ADS)

    Wei, J. C.; Yang, W.; Johnson, J. E.; Zhao, P.; Gerasimov, I. V.; Pham, L.; Vicente, G. A.; Shen, S.

    2014-12-01

    Satellite data products are important for a wide variety of applications that can bring far-reaching benefits to the science community and the broader society. These benefits can best be achieved if the satellite data are well utilized and interpreted, such as model inputs from satellite, or extreme event (such as volcano eruption, dust storm, …etc) interpretation from satellite. Unfortunately, this is not always the case, despite the abundance and relative maturity of numerous satellite data products provided by NASA and other organizations. One way to help users better understand the satellite data is to provide data along with 'Images', including accurate pixel-level (Level 2) information, pixel coverage area delineation, and science team recommended quality screening for individual geophysical parameters. Goddard Earth Sciences Data and Information Services Center (GES DISC) always strives to best support (i.e., Software-as-a-service, SaaS) the user-community for NASA Earth Science Data. In this case, we will present a new visualization tool that helps users exploiting Aura Ozone Monitoring Instrument (OMI) Level 2 data. This new visualization service utilizes Open Geospatial Consortium (OGC) standard-compliant Web Mapping Service (WMS) and Web Coverage Service (WCS) calls in the backend infrastructure. The functionality of the service allows users to select data sources (e.g., multiple parameters under the same measurement, like NO2 and SO2 from OMI Level 2 or same parameter with different methods of aggregation, like NO2 in OMNO2G and OMNO2D products), defining area-of-interest and temporal extents, zooming, panning, overlaying, sliding, and data subsetting and reformatting. The interface will also be able to connect to other OGC WMS and WCS servers, which will greatly enhance its expandability to integrate additional outside data/map sources (such as Global Imagery Browse Services (GIBS)).

  15. Birds of a Feather: Neanderthal Exploitation of Raptors and Corvids

    PubMed Central

    Finlayson, Clive; Brown, Kimberly; Blasco, Ruth; Rosell, Jordi; Negro, Juan José; Finlayson, Geraldine; Sánchez Marco, Antonio; Giles Pacheco, Francisco; Rodríguez Vidal, Joaquín; Carrión, José S.; Fa, Darren A.; Rodríguez Llanes, José M.

    2012-01-01

    The hypothesis that Neanderthals exploited birds for the use of their feathers or claws as personal ornaments in symbolic behaviour is revolutionary as it assigns unprecedented cognitive abilities to these hominins. This inference, however, is based on modest faunal samples and thus may not represent a regular or systematic behaviour. Here we address this issue by looking for evidence of such behaviour across a large temporal and geographical framework. Our analyses try to answer four main questions: 1) does a Neanderthal to raptor-corvid connection exist at a large scale, thus avoiding associations that might be regarded as local in space or time?; 2) did Middle (associated with Neanderthals) and Upper Palaeolithic (associated with modern humans) sites contain a greater range of these species than Late Pleistocene paleontological sites?; 3) is there a taphonomic association between Neanderthals and corvids-raptors at Middle Palaeolithic sites on Gibraltar, specifically Gorham's, Vanguard and Ibex Caves? and; 4) was the extraction of wing feathers a local phenomenon exclusive to the Neanderthals at these sites or was it a geographically wider phenomenon?. We compiled a database of 1699 Pleistocene Palearctic sites based on fossil bird sites. We also compiled a taphonomical database from the Middle Palaeolithic assemblages of Gibraltar. We establish a clear, previously unknown and widespread, association between Neanderthals, raptors and corvids. We show that the association involved the direct intervention of Neanderthals on the bones of these birds, which we interpret as evidence of extraction of large flight feathers. The large number of bones, the variety of species processed and the different temporal periods when the behaviour is observed, indicate that this was a systematic, geographically and temporally broad, activity that the Neanderthals undertook. Our results, providing clear evidence that Neanderthal cognitive capacities were comparable to those of

  16. Exploiting mosquito sugar feeding to detect mosquito-borne pathogens

    PubMed Central

    Hall-Mendelin, Sonja; Ritchie, Scott A.; Johansen, Cheryl A.; Zborowski, Paul; Cortis, Giles; Dandridge, Scott; Hall, Roy A.; van den Hurk, Andrew F.

    2010-01-01

    Arthropod-borne viruses (arboviruses) represent a global public health problem, with dengue viruses causing millions of infections annually, while emerging arboviruses, such as West Nile, Japanese encephalitis, and chikungunya viruses have dramatically expanded their geographical ranges. Surveillance of arboviruses provides vital data regarding their prevalence and distribution that may be utilized for biosecurity measures and the implementation of disease control strategies. However, current surveillance methods that involve detection of virus in mosquito populations or sero-conversion in vertebrate hosts are laborious, expensive, and logistically problematic. We report a unique arbovirus surveillance system to detect arboviruses that exploits the process whereby mosquitoes expectorate virus in their saliva during sugar feeding. In this system, infected mosquitoes captured by CO2-baited updraft box traps are allowed to feed on honey-soaked nucleic acid preservation cards within the trap. The cards are then analyzed for expectorated virus using real-time reverse transcription-PCR. In field trials, this system detected the presence of Ross River and Barmah Forest viruses in multiple traps deployed at two locations in Australia. Viral RNA was preserved for at least seven days on the cards, allowing for long-term placement of traps and continuous collection of data documenting virus presence in mosquito populations. Furthermore no mosquito handling or processing was required and cards were conveniently shipped to the laboratory overnight. The simplicity and efficacy of this approach has the potential to transform current approaches to vector-borne disease surveillance by streamlining the monitoring of pathogens in vector populations. PMID:20534559

  17. Birds of a feather: Neanderthal exploitation of raptors and corvids.

    PubMed

    Finlayson, Clive; Brown, Kimberly; Blasco, Ruth; Rosell, Jordi; Negro, Juan José; Bortolotti, Gary R; Finlayson, Geraldine; Sánchez Marco, Antonio; Giles Pacheco, Francisco; Rodríguez Vidal, Joaquín; Carrión, José S; Fa, Darren A; Rodríguez Llanes, José M

    2012-01-01

    The hypothesis that Neanderthals exploited birds for the use of their feathers or claws as personal ornaments in symbolic behaviour is revolutionary as it assigns unprecedented cognitive abilities to these hominins. This inference, however, is based on modest faunal samples and thus may not represent a regular or systematic behaviour. Here we address this issue by looking for evidence of such behaviour across a large temporal and geographical framework. Our analyses try to answer four main questions: 1) does a Neanderthal to raptor-corvid connection exist at a large scale, thus avoiding associations that might be regarded as local in space or time?; 2) did Middle (associated with Neanderthals) and Upper Palaeolithic (associated with modern humans) sites contain a greater range of these species than Late Pleistocene paleontological sites?; 3) is there a taphonomic association between Neanderthals and corvids-raptors at Middle Palaeolithic sites on Gibraltar, specifically Gorham's, Vanguard and Ibex Caves? and; 4) was the extraction of wing feathers a local phenomenon exclusive to the Neanderthals at these sites or was it a geographically wider phenomenon?. We compiled a database of 1699 Pleistocene Palearctic sites based on fossil bird sites. We also compiled a taphonomical database from the Middle Palaeolithic assemblages of Gibraltar. We establish a clear, previously unknown and widespread, association between Neanderthals, raptors and corvids. We show that the association involved the direct intervention of Neanderthals on the bones of these birds, which we interpret as evidence of extraction of large flight feathers. The large number of bones, the variety of species processed and the different temporal periods when the behaviour is observed, indicate that this was a systematic, geographically and temporally broad, activity that the Neanderthals undertook. Our results, providing clear evidence that Neanderthal cognitive capacities were comparable to those of

  18. Trends in the exploitation of South Atlantic shark populations.

    PubMed

    Barreto, Rodrigo; Ferretti, Francesco; Flemming, Joanna M; Amorim, Alberto; Andrade, Humber; Worm, Boris; Lessa, Rosangela

    2016-08-01

    Approximately 25% of globally reported shark catches occur in Atlantic pelagic longline fisheries. Strong declines in shark populations have been detected in the North Atlantic, whereas in the South Atlantic the situation is less clear, although fishing effort has been increasing in this region since the late 1970s. We synthesized information on shark catch rates (based on 871,177 sharks caught on 86,492 longline sets) for the major species caught by multiple fleets in the South Atlantic between 1979 and 2011. We complied records from fishing logbooks of fishing companies, fishers, and onboard observers that were supplied to Brazilian institutions. By using exploratory data analysis and literature sources, we identified 3 phases of exploitation in these data (Supporting Information). From 1979 to 1997 (phase A), 5 fleets (40 vessels) fished mainly for tunas. From 1998 to 2008 (phase B), 20 fleets (100 vessels) fished for tunas, swordfishes, and sharks. From 2008 to 2011 (phase C), 3 fleets (30 vessels) fished for multiple species, but restrictive measures were implemented. We used generalized linear models to standardize catch rates and identify trends in each of these phases. Shark catch rates increased from 1979 to 1997, when fishing effort was low, decreased from 1998 to 2008, when fishing effort increased substantially, and remained stable or increased from 2008 to 2011, when fishing effort was again low. Our results indicate that most shark populations affected by longlines in the South Atlantic are currently depleted, but these populations may recover if fishing effort is reduced accordingly. In this context, it is problematic that comprehensive data collection, monitoring, and management of these fisheries ceased after 2012. Concurrently with the fact that Brazil is newly identified by FAO among the largest (and in fastest expansion) shark sub-products consumer market worldwide.

  19. Making Precise Resonators for Mesoscale Vibratory Gyroscopes

    NASA Technical Reports Server (NTRS)

    Yang, Eui-Hyeok

    2004-01-01

    An alternative approach to the design and fabrication of vibratory gyroscopes is founded on the use of fabrication techniques that yield best results in the mesoscopic size range, which is characterized by overall device dimensions of the order of a centimeter. This approach stands in contradistinction to prior approaches in (1) the macroscopic size range (the size range of conventional design and fabrication, characterized by overall device dimensions of many centimeters) and (2) the microscopic size range [the size range of microelectromechanical systems (MEMS), characterized by overall device dimensions of the order of a millimeter or less]. The mesoscale approach offers some of the advantage of the MEMS approach (sizes and power demands smaller than those of the macroscale approach) and some of the advantage of the macroscale approach (the possibility of achieving relative dimensional precision greater than that of the MEMS approach). Relative dimensional precision is a major issue in the operation of a vibratory gyroscope. The heart of a vibratory gyroscope is a mechanical resonator that is required to have a specified symmetry in a plane orthogonal to the axis about which rotation is to be measured. If the resonator could be perfectly symmetrical, then in the absence of rotation, a free vibration of the resonator could remain fixed along any orientation relative to its housing; that is, the gyroscope could exhibit zero drift. In practice, manufacturing imprecision gives rise to some asymmetry in mass, flexural stiffness or dissipation, resulting in a slight drift or beating motion of an initial vibration pattern that cannot be distinguished from rotation. In the mesoscale approach, one exploits the following concepts: For a given amount of dimensional error generated in manufacturing, the asymmetry and hence the rate-of-rotation drift of the gyroscope can be reduced by increasing the scale. The decrease in asymmetry also reduces coupling of vibrations to the

  20. Investigation of fiber Bragg grating based mode-splitting resonant sensors.

    PubMed

    Campanella, Carlo Edoardo; Mastronardi, Lorenzo; De Leonardis, Francesco; Malara, Pietro; Gagliardi, Gianluca; Passaro, Vittorio M N

    2014-10-20

    In this paper, we report on theoretical investigation of split mode resonant sensors based on fiber Bragg grating (FBG) ring resonators and π-shifted fiber Bragg grating (π-FBG) ring resonators. By using a π-shifted Bragg grating ring resonator (π-FBGRR) instead of a conventional fiber Bragg grating ring resonator (FBGRR), the symmetric and antisymmetric resonance branches (i.e., the eigen-modes of the perturbed system) show peculiar and very important features that can be exploited to improve the performance of the fiber optic spectroscopic sensors. In particular, the π-FBGRR symmetric resonance branch can be taylored to have a maximum splitting sensitivity to small environmental perturbations. This optimal condition has been found around the crossing points of the two asymmetric resonance branches, by properly choosing the physical parameters of the system. Then, high sensitivity splitting mode sensors are theoretically demonstrated showing, as an example, a strain sensitivity improvement of at least one order of magnitude over the state-of-the-art.

  1. THz Pyro-Optical Detector Based on LiNbO3 Whispering Gallery Mode Microdisc Resonator

    PubMed Central

    Cosci, Alessandro; Cerminara, Matteo; Nunzi Conti, Gualtiero; Soria, Silvia; Righini, Giancarlo C.; Pelli, Stefano

    2017-01-01

    This study analyzes the capabilities of a LiNbO3 whispering gallery mode microdisc resonator as a potential bolometer detector in the THz range. The resonator is theoretically characterized in the stationary regime by its thermo-optic and thermal coefficients. Considering a Q-factor of 107, a minimum detectable power of 20 μW was evaluated, three orders of magnitude above its noise equivalent power. This value opens up the feasibility of exploiting LiNbO3 disc resonators as sensitive room-temperature detectors in the THz range. PMID:28134857

  2. Search for neutral resonances decaying into a Z boson and a pair of b jets or τ leptons

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Knünz, V.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; De Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Van Parijs, I.; Barria, P.; Brun, H.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Fasanella, G.; Favart, L.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Maerschalk, T.; Marinov, A.; Perniè, L.; Randle-Conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Yonamine, R.; Zenoni, F.; Zhang, F.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Dobur, D.; Fagot, A.; Garcia, G.; Gul, M.; Mccartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva, S.; Sigamani, M.; Tytgat, M.; Van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Musich, M.; Nuttens, C.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Correa Martins, M.; Hamer, M.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; De Souza Santos, A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Micanovic, S.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Bodlak, M.; Finger, M.; Finger, M.; El-khateeb, E.; Elkafrawy, T.; Mohamed, A.; Salama, E.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Davignon, O.; Filipovic, N.; Granier de Cassagnac, R.; Jo, M.; Lisniak, S.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Merlin, J. A.; Skovpen, K.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Bernet, C.

    2016-08-01

    A search is performed for a new resonance decaying into a lighter resonance and a Z boson. Two channels are studied, targeting the decay of the lighter resonance into either a pair of oppositely charged τ leptons or a b b ‾ pair. The Z boson is identified via its decays to electrons or muons. The search exploits data collected by the CMS experiment at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.8 fb-1. No significant deviations are observed from the standard model expectation and limits are set on production cross sections and parameters of two-Higgs-doublet models.

  3. Nonlinear damping in mechanical resonators made from carbon nanotubes and graphene

    NASA Astrophysics Data System (ADS)

    Eichler, A.; Moser, J.; Chaste, J.; Zdrojek, M.; Wilson-Rae, I.; Bachtold, A.

    2011-06-01

    The theory of damping is discussed in Newton's Principia and has been tested in objects as diverse as the Foucault pendulum, the mirrors in gravitational-wave detectors and submicrometre mechanical resonators. In general, the damping observed in these systems can be described by a linear damping force. Advances in nanofabrication mean that it is now possible to explore damping in systems with one or more atomic-scale dimensions. Here we study the damping of mechanical resonators based on carbon nanotubes and graphene sheets. The damping is found to strongly depend on the amplitude of motion, and can be described by a nonlinear rather than a linear damping force. We exploit the nonlinear nature of damping in these systems to improve the figures of merit for both nanotube and graphene resonators. For instance, we achieve a quality factor of 100,000 for a graphene resonator.

  4. Far from Equilibrium Percolation, Stochastic and Shape Resonances in the Physics of Life

    PubMed Central

    Poccia, Nicola; Ansuini, Alessio; Bianconi, Antonio

    2011-01-01

    Key physical concepts, relevant for the cross-fertilization between condensed matter physics and the physics of life seen as a collective phenomenon in a system out-of-equilibrium, are discussed. The onset of life can be driven by: (a) the critical fluctuations at the protonic percolation threshold in membrane transport; (b) the stochastic resonance in biological systems, a mechanism that can exploit external and self-generated noise in order to gain efficiency in signal processing; and (c) the shape resonance (or Fano resonance or Feshbach resonance) in the association and dissociation processes of bio-molecules (a quantum mechanism that could play a key role to establish a macroscopic quantum coherence in the cell). PMID:22072921

  5. Nonlinear damping in mechanical resonators made from carbon nanotubes and graphene.

    PubMed

    Eichler, A; Moser, J; Chaste, J; Zdrojek, M; Wilson-Rae, I; Bachtold, A

    2011-05-15

    The theory of damping is discussed in Newton's Principia and has been tested in objects as diverse as the Foucault pendulum, the mirrors in gravitational-wave detectors and submicrometre mechanical resonators. In general, the damping observed in these systems can be described by a linear damping force. Advances in nanofabrication mean that it is now possible to explore damping in systems with one or more atomic-scale dimensions. Here we study the damping of mechanical resonators based on carbon nanotubes and graphene sheets. The damping is found to strongly depend on the amplitude of motion, and can be described by a nonlinear rather than a linear damping force. We exploit the nonlinear nature of damping in these systems to improve the figures of merit for both nanotube and graphene resonators. For instance, we achieve a quality factor of 100,000 for a graphene resonator.

  6. Far from equilibrium percolation, stochastic and shape resonances in the physics of life.

    PubMed

    Poccia, Nicola; Ansuini, Alessio; Bianconi, Antonio

    2011-01-01

    Key physical concepts, relevant for the cross-fertilization between condensed matter physics and the physics of life seen as a collective phenomenon in a system out-of-equilibrium, are discussed. The onset of life can be driven by: (a) the critical fluctuations at the protonic percolation threshold in membrane transport; (b) the stochastic resonance in biological systems, a mechanism that can exploit external and self-generated noise in order to gain efficiency in signal processing; and (c) the shape resonance (or Fano resonance or Feshbach resonance) in the association and dissociation processes of bio-molecules (a quantum mechanism that could play a key role to establish a macroscopic quantum coherence in the cell).

  7. Advanced coupled-micro-resonator architectures for dispersion and spectral engineering applications

    NASA Astrophysics Data System (ADS)

    Van, Vien

    2009-02-01

    We report recent progress in the design and fabrication of coupled optical micro-resonators and their applications in realizing compact OEIC devices for optical spectral engineering. By leveraging synthesis techniques for analog and digital electrical circuits, advanced coupled-microring device architectures can be realized with the complexity and functionality approaching that of state-of-the-art microwave filters. In addition, the traveling wave nature of microring resonators can be exploited to realize novel devices not possible with standing wave resonators. Applications of coupledmicro- resonator devices in realizing complex optical transfer functions for amplitude, phase and group delay engineering will be presented. Progress in the practical implementation of these devices in the Silicon-on-Insulator OEIC platform will be highlighted along with the challenges and potential for constructing very high order optical filters using coupledmicroring architectures.

  8. Optimal exploitation strategies for an animal population in a Markovian environment: A theory and an example

    USGS Publications Warehouse

    Anderson, D.R.

    1975-01-01

    Optimal exploitation strategies were studied for an animal population in a Markovian (stochastic, serially correlated) environment. This is a general case and encompasses a number of important special cases as simplifications. Extensive empirical data on the Mallard (Anas platyrhynchos) were used as an example of general theory. The number of small ponds on the central breeding grounds was used as an index to the state of the environment. A general mathematical model was formulated to provide a synthesis of the existing literature, estimates of parameters developed from an analysis of data, and hypotheses regarding the specific effect of exploitation on total survival. The literature and analysis of data were inconclusive concerning the effect of exploitation on survival. Therefore, two hypotheses were explored: (1) exploitation mortality represents a largely additive form of mortality, and (2) exploitation mortality is compensatory with other forms of mortality, at least to some threshold level. Models incorporating these two hypotheses were formulated as stochastic dynamic programming models and optimal exploitation strategies were derived numerically on a digital computer. Optimal exploitation strategies were found to exist under the rather general conditions. Direct feedback control was an integral component in the optimal decision-making process. Optimal exploitation was found to be substantially different depending upon the hypothesis regarding the effect of exploitation on the population. If we assume that exploitation is largely an additive force of mortality in Mallards, then optimal exploitation decisions are a convex function of the size of the breeding population and a linear or slight concave function of the environmental conditions. Under the hypothesis of compensatory mortality forces, optimal exploitation decisions are approximately linearly related to the size of the Mallard breeding population. Dynamic programming is suggested as a very general

  9. Rethinking research on sexual exploitation of boys: Methodological challenges and recommendations to optimize future knowledge generation.

    PubMed

    Mitchell, Katherine; Moynihan, Melissa; Pitcher, Claire; Francis, Annabel; English, Abigail; Saewyc, Elizabeth

    2017-02-09

    Research and policies on child and adolescent sexual exploitation frequently focus on the sexual exploitation of girls and fail to recognize the experiences of sexually exploited boys, including their potentially unique health care and social support needs. This oversight limits the ability of health care and social service providers to offer both targeted and evidence informed care to sexually exploited boys. As a first step in a larger grant to understand the experiences of sexually exploited boys and to develop interventions for this specific population, we conducted a systematic review to address the question, "What is the state of the research on sexually exploited boys internationally?" As we undertook this review, we faced a number of significant challenges that made the process more difficult than anticipated. In this paper we discuss four key methodological challenges we encountered: lack of a consistent definition of child and adolescent sexual exploitation, difficulties in differentiating sexual exploitation as a specific concept within child sexual abuse, failure to disaggregate data usefully across multiple variables, and limited epidemiological studies to inform prevalence. We reflect on how these challenges limited our ability to systematically analyze, synthesize, and interpret the available research. We conclude by making recommendations to improve the state of the research regarding sexually exploited boys with the aim of better informing future policy and practice.

  10. The impact of forest exploitation on Amazonian stingless bees (Apidae, Meliponini).

    PubMed

    Venturieri, G C

    2009-01-01

    The protocols available to sustainably exploit natural forest resources are known as "sustainable forest management". This type of management generally does not take into account the effect of timber exploitation on pollinators. Stingless bees, which include many species that play an important role as pollinators and are quite diverse in the Amazon, preferentially make their perennial nests in the base of hollow trees. Normally, during sustainable exploitation of trees, hollow trees are not cut down; however, predatory exploitation of such trees could severely affect natural populations of this pollinator group.

  11. Electroexcitation of nucleon resonances

    SciTech Connect

    Inna Aznauryan, Volker D. Burkert

    2012-01-01

    We review recent progress in the investigation of the electroexcitation of nucleon resonances, both in experiment and in theory. The most accurate results have been obtained for the electroexcitation amplitudes of the four lowest excited states, which have been measured in a range of Q2 up to 8 and 4.5 GeV2 for the Delta(1232)P33, N(1535)S11 and N(1440)P11, N(1520)D13, respectively. These results have been confronted with calculations based on lattice QCD, large-Nc relations, perturbative QCD (pQCD), and QCD-inspired models. The amplitudes for the Delta(1232) indicate large pion-cloud contributions at low Q2 and don't show any sign of approaching the pQCD regime for Q2<7 GeV2. Measured for the first time, the electroexcitation amplitudes of the Roper resonance, N(1440)P11, provide strong evidence for this state as a predominantly radial excitation of a three-quark (3q) ground state, with additional non-3-quark contributions needed to describe the low Q2 behavior of the amplitudes. The longitudinal transition amplitude for the N(1535)S11 was determined and has become a challenge for quark models. Explanations may require large meson-cloud contributions or alternative representations of this state. The N(1520)D13 clearly shows the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at Q2 > 0.5 GeV2, confirming a long-standing prediction of the constituent quark model. The interpretation of the moments of resonance transition form factors in terms of transition transverse charge distributions in infinite momentum frame is presented.

  12. Seismic Resonant Emission

    NASA Astrophysics Data System (ADS)

    Korneev, V. A.

    2007-12-01

    There are several classes of underground objects which can produce resonant emission after being hit by incident seismic waves. Those objects include tunnels, pipes, buried containers, ground-filled excavations, unexploded ordinances, fluid-filled fractures, mine shafts, and the like. Being high contrast scatterers, these objects are capable of generating strong scattered waves where primary PP, PS, SS waves carry away most of the energy which was brought by incident waves. For both high- and low- velocity objects the primary scattered waves have the same order of magnitude as incident waves. The main difference between these groups of objects is in later arrivals of multiple scattered waves. While high-velocity objects effectively radiate most of the energy soon after impact, the low-velocity objects trap some fraction of incident wave energy in the form of circumferential waves which propagate rotating along the interface between the object and the embedding medium. Circumferential waves include surface Rayleigh-type waves (propagating mostly in the embedding medium), Stoneley waves (propagating mostly in the fluid, if present), and Frantz waves (body waves trapped in the object because of its curvature). Strong impedance contrast ensures small radiation loss for circumferential waves and they slowly decay in amplitude while rotating inside/around the object. Some circumferential waves exist in the high-velocity objects but their amplitudes decay very fast because of strong radiation in outer medium. Most of the secondary (multiply reflected from an object's boundaries or multiply circled around the object) resonant-scattered energy radiates in the embedding medium as shear waves. The possibility of neglecting P- waves in late scattering arrivals simplifies imaging as is demonstrated for the field and modeled data of the example. Resonant emission phenomenon provides an effective tool for active monitoring for a number of applications such as tunnel detection

  13. Resonance test system

    DOEpatents

    Musial, Walter [Boulder, CO; White, Darris [Superior, CO

    2011-05-31

    An apparatus (10) for applying at least one load to a specimen (12) according to one embodiment of the invention may comprise a mass (18). An actuator (20) mounted to the specimen (12) and operatively associated with the mass (18) moves the mass (18) along a linear displacement path (22) that is perpendicular to a longitudinal axis of the specimen (12). A control system (26) operatively associated with the actuator (20) operates the actuator (20) to reciprocate the mass (18) along the linear displacement path (22) at a reciprocating frequency, the reciprocating frequency being about equal to a resonance frequency of the specimen (12) in a test configuration.

  14. Nanotube resonator devices

    DOEpatents

    Jensen, Kenneth J; Zettl, Alexander K; Weldon, Jeffrey A

    2014-05-06

    A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

  15. Ellipsometric surface plasmon resonance

    NASA Astrophysics Data System (ADS)

    Hsu, Wei-Liang; Lee, Shu-Sheng; Lee, Chih-Kung

    2009-03-01

    We develop a new multifunctional optical biochip system that integrates an ellipsometer with a surface plasmon resonance (SPR) feature. This newly developed biochip biosensor, which we call ESPR for an ellipsometric SPR, provides us with a system to retrieve detailed information such as the optical properties of immobilized biomolecular monolayers, surface concentration variations of biomedical reactions, and kinetic affinity between biomolecules required for further biotech analysis. Our ESPR can also serve as both a research and development tool and a manufacturing tool for various biomedical applications.

  16. Pressure dependent resonant frequency of micromechanical drumhead resonators

    SciTech Connect

    Southworth, D. R.; Craighead, H. G.; Parpia, J. M.

    2009-05-25

    We examine the relationship between squeeze film effects and resonance frequency in drum-type resonators. We find that the resonance frequency increases linearly with pressure as a result of the additional restoring force contribution from compression of gas within the drum cavity. We demonstrate trapping of the gas by squeeze film effects and geometry. The pressure sensitivity is shown to scale inversely with cavity height and sound radiation is found to be the predominant loss mechanism near and above atmospheric pressure. Drum resonators exhibit linearity and sensitivity suitable to barometry from below 10 Torr up to several atmospheres.

  17. Scattering-Type Surface-Plasmon-Resonance Biosensors

    NASA Technical Reports Server (NTRS)

    Wang, Yu; Pain, Bedabrata; Cunningham, Thomas; Seshadri, Suresh

    2005-01-01

    Biosensors of a proposed type would exploit scattering of light by surface plasmon resonance (SPR). Related prior biosensors exploit absorption of light by SPR. Relative to the prior SPR biosensors, the proposed SPR biosensors would offer greater sensitivity in some cases, enough sensitivity to detect bioparticles having dimensions as small as nanometers. A surface plasmon wave can be described as a light-induced collective oscillation in electron density at the interface between a metal and a dielectric. At SPR, most incident photons are either absorbed or scattered at the metal/dielectric interface and, consequently, reflected light is greatly attenuated. The resonance wavelength and angle of incidence depend upon the permittivities of the metal and dielectric. An SPR sensor of the type most widely used heretofore includes a gold film coated with a ligand a substance that binds analyte molecules. The gold film is thin enough to support evanescent-wave coupling through its thickness. The change in the effective index of refraction at the surface, and thus the change in the SPR response, increases with the number of bound analyte molecules. The device is illuminated at a fixed wavelength, and the intensity of light reflected from the gold surface opposite the ligand-coated surface is measured as a function of the angle of incidence. From these measurements, the angle of minimum reflection intensity is determined

  18. Virtual Geophysics Laboratory: Exploiting the Cloud and Empowering Geophysicsts

    NASA Astrophysics Data System (ADS)

    Fraser, Ryan; Vote, Josh; Goh, Richard; Cox, Simon

    2013-04-01

    Over the last five decades geoscientists from Australian state and federal agencies have collected and assembled around 3 Petabytes of geoscience data sets under public funding. As a consequence of technological progress, data is now being acquired at exponential rates and in higher resolution than ever before. Effective use of these big data sets challenges the storage and computational infrastructure of most organizations. The Virtual Geophysics Laboratory (VGL) is a scientific workflow portal addresses some of the resulting issues by providing Australian geophysicists with access to a Web 2.0 or Rich Internet Application (RIA) based integrated environment that exploits eResearch tools and Cloud computing technology, and promotes collaboration between the user community. VGL simplifies and automates large portions of what were previously manually intensive scientific workflow processes, allowing scientists to focus on the natural science problems, rather than computer science and IT. A number of geophysical processing codes are incorporated to support multiple workflows. For example a gravity inversion can be performed by combining the Escript/Finley codes (from the University of Queensland) with the gravity data registered in VGL. Likewise, tectonic processes can also be modeled by combining the Underworld code (from Monash University) with one of the various 3D models available to VGL. Cloud services provide scalable and cost effective compute resources. VGL is built on top of mature standards-compliant information services, many deployed using the Spatial Information Services Stack (SISS), which provides direct access to geophysical data. A large number of data sets from Geoscience Australia assist users in data discovery. GeoNetwork provides a metadata catalog to store workflow results for future use, discovery and provenance tracking. VGL has been developed in collaboration with the research community using incremental software development practices and open

  19. Integration of hard copy and soft copy exploitation

    NASA Astrophysics Data System (ADS)

    Fultz, Roy C., Jr.

    1996-11-01

    Exploitation of remotely sensed and aerially derived imagery has, in the past, been primarily performed through the use of analog light tables, by displaying individual pieces or rolls of imagery over a brightly lit surface to allow light through the nonopaque surface of the film medium. The interpreter would then peer through optical viewing scopes allowing him (or her) to analyze the imagery. Over the course of the last two decades, digital data, or as it is better known, "softcopy imagery," has for many become the desired path which technology has dictated. Softcopy imagery offers many benefits, such as the ability to manipulate imagery in ways analog workstations cannot and were never designed to do. Functions which can be performed on softcopy imagery are endless and growing constantly: image spatial rectification, pixel manipulation, image contrast, and brightness enhancements. All are performed by the running of algorithmic equations to manipulate the digital data. It has become evident that in the future a large portion of imagery analysis will be performed by softcopy. However, studies indicate that aerial imagery will continue to be acquired via hardcopy means for many civil, educational, and commercial applications in the foreseeable future, making it clear that any large scale transformation from hardcopy to softcopy will not be feasible for a long time to come. A major issue dictating the slow-down in this transition is the over 35 years of hardcopy imagery archived and housed in facilities throughout the world, including the recently declassified "Corona" satellite imagery which will provide a wealth of hardcopy data for use by ecologists and conservationists. Yes, the technology to transfer hardcopy to softcopy exists, but the time and cost required to complete this task would be phenomenal and, in many cases, when digitization and storage become affordable, it still may prove beneficial to retain the imagery in a hardcopy form for retention of the

  20. Exploiting Aerobic Fitness To Reduce Risk Of Hypobaric Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Gernhardt, Michael L.; Wessel, James H., III

    2007-01-01

    Decompression sickness (DCS) is multivariable. But we hypothesize an aerobically fit person is less likely to experience hypobaric DCS than an unfit person given that fitness is exploited as part of the denitrogenation (prebreathe, PB) process prior to an altitude exposure. Aerobic fitness is peak oxygen uptake (VO2pk, ml/kg/min). METHODS: Treadmill or cycle protocols were used over 15 years to determine VO2pks. We evaluated dichotomous DCS outcome and venous gas emboli (VGE) outcome detected in the pulmonary artery with Doppler ultrasound associated with VO2pk for two classes of experiments: 1) those with no PB or PB under resting conditions prior to ascent in an altitude chamber, and 2) PB that included exercise for some part of the PB. There were 165 exposures (mean VO2pk 40.5 +/- 7.6 SD) with 25 cases of DCS in the first protocol class and 172 exposures (mean VO2pk 41.4 +/- 7.2 SD) with 25 cases of DCS in the second. Similar incidence of the DCS (15.2% vs. 14.5%) and VGE (45.5% vs. 44.8%) between the two classes indicates that decompression stress was similar. The strength of association between outcome and VO2pk was evaluated using univariate logistic regression. RESULTS: An inverse relationship between the DCS outcome and VO2pk was evident, but the relationship was strongest when exercise was done as part of the PB (exercise PB, coef. = -0.058, p = 0.07; rest or no PB, coef. = -0.005, p = 0.86). There was no relationship between VGE outcome and VO2pk (exercise PB, coef. = -0.003, p = 0.89; rest or no PB, coef. = 0.014, p = 0.50). CONCLUSIONS: A significant change in probability of DCS was associated with fitness only when exercise was included in the denitrogenation process. We believe a fit person that exercises during PB efficiently eliminates dissolved nitrogen from tissues.

  1. Exploiting Aerobic Fitness to Reduce Risk of Hypobaric Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Conkin, J.; Gernhardt, M. L.; Wessel, J. H.

    2007-01-01

    Decompression sickness (DCS) is multivariable. But we hypothesize an aerobically fit person is less likely to experience hypobaric DCS than an unfit person given that fitness is exploited as part of the denitrogenation (prebreathe, PB) process prior to an altitude exposure. Aerobic fitness is peak oxygen uptake (VO2pk, ml/kg/min). Treadmill or cycle protocols were used over 15 years to determine VO2pks. We evaluated dichotomous DCS outcome and venous gas emboli (VGE) outcome detected in the pulmonary artery with Doppler ultrasound associated with VO2pk for two classes of experiments: 1) those with no PB or PB under resting conditions prior to ascent in an altitude chamber, and 2) PB that included exercise for some part of the PB. There were 165 exposures (mean VO2pk 40.5 plus or minus 7.6 SD) with 25 cases of DCS in the first protocol class and 172 exposures (mean VO2pk 41.4 plus or minus 7.2 SD) with 25 cases of DCS in the second. Similar incidence of the DCS (15.2% vs. 14.5%) and VGE (45.5% vs. 44.8%) between the two classes indicates that decompression stress was similar. The strength of association between outcome and VO2pk was evaluated using univariate logistic regression. An inverse relationship between the DCS outcome and VO2pk was evident, but the relationship was strongest when exercise was done as part of the PB (exercise PB, coef. = -0.058, p = 0.07; rest or no PB, coef. = -0.005, p = 0.86). There was no relationship between VGE outcome and VO2pk (exercise PB, coef. = -0.003, p = 0.89; rest or no PB, coef. = 0.014, p = 0.50). A significant change in probability of DCS was associated with fitness only when exercise was included in the denitrogenation process. We believe a fit person that exercises during PB efficiently eliminates dissolved nitrogen from tissues.

  2. Ultracompact nonreciprocal optical isolator based on guided resonance in a magneto-optical photonic crystal slab.

    PubMed

    Fang, Kejie; Yu, Zongfu; Liu, Victor; Fan, Shanhui

    2011-11-01

    We design an ultracompact optical isolator with normal incident geometry that operates with a bandwidth that is substantial for a device of this size. For operation in a telecommunication wavelength of 1.55 μm, the thickness of the device is less than 1 μm and the device supports an operating bandwidth of 400 GHz over which the minimum contrast ratio exceeds 25 dB. Our design utilizes guided resonance in a photonic crystal slab to enhance magneto-optical effects, and exploits interference effects among multiple resonances to create desired transmission spectral line shapes.

  3. Grating-coupled surface plasmon resonance in conical mounting with polarization modulation.

    PubMed

    Ruffato, G; Romanato, F

    2012-07-01

    A grating-coupled surface plasmon resonance (GCSPR) technique based on polarization modulation in conical mounting is presented. A metallic grating is azimuthally rotated to support double-surface plasmon polariton excitation and exploit the consequent sensitivity enhancement. Corresponding to the resonance polar angle, a polarization scan of incident light is performed, and reflectivity data are collected before and after functionalization with a dodecanethiol self-assembled monolayer. The output signal exhibits a harmonic dependence on polarization, and the phase term is used as a parameter for sensing. This technique offers the possibility of designing extremely compact, fast, and cheap high-resolution plasmonic sensors based on GCSPR.

  4. Low power and compact reconfigurable multiplexing devices based on silicon microring resonators.

    PubMed

    Dong, Po; Qian, Wei; Liang, Hong; Shafiiha, Roshanak; Feng, Ning-Ning; Feng, Dazeng; Zheng, Xuezhe; Krishnamoorthy, Ashok V; Asghari, Mehdi

    2010-05-10

    We present thermally reconfigurable multiplexing devices based on silicon microring resonators with low tuning power and low thermal crosstalk. Micro-heaters on top of the rings are employed to tune the resonant wavelengths through the thermo-optic effect of silicon. We achieve a low tuning power of 21 mW per free spectral range for a single ring by exploiting thermal isolation trenches close to the ring waveguides. Negligible thermal crosstalk is demonstrated for rings spaced by 15 microm, enabling compact multiplexing devices. The tuning time constant is demonstrated to be less than 10 micros.

  5. A nanoradio utilizing the mechanical resonance of a vertically aligned nanopillar array.

    PubMed

    Lee, Chang Hwa; Lee, Seok Woo; Lee, Seung S

    2014-02-21

    A nanoradio based on the mechanical resonance of a nanomaterial has promising applications in terms of size reduction of an antenna and integrity of all components of a radio except a speaker. In this letter, a nanopillar array radio utilizing the mechanical resonance of a vertically aligned nanopillar array is realized by a reliable top-down method. By exploiting the field emission phenomenon, it was found that the nanopillar array functions as a radio with a demodulator without any electrical circuitry. The array of vertically aligned nanopillars increases the demodulated current and signal to noise ratio, and this fabrication method makes manipulation and positioning of nanostructures possible intrinsically for industrial applications.

  6. nuclear magnetic resonance gyroscope

    SciTech Connect

    Karwacki, F. A.; Griffin, J.

    1985-04-02

    A nuclear magnetic resonance gyroscope which derives angular rotation thereof from the phases of precessing nuclear moments utilizes a single-resonance cell situated in the center of a uniform DC magnetic field. The field is generated by current flow through a circular array of coils between parallel plates. It also utilizes a pump and read-out beam and associated electronics for signal processing and control. Encapsulated in the cell for sensing rotation are odd isotopes of Mercury Hg/sup 199/ and Hg/sup 201/. Unpolarized intensity modulated light from a pump lamp is directed by lenses to a linear polarizer, quarter wave plate combination producing circularly polarized light. The circularly polarized light is reflected by a mirror to the cell transverse to the field for optical pumping of the isotopes. Unpolarized light from a readout lamp is directed by lenses to another linear polarizer. The linearly polarized light is reflected by another mirror to the cell transverse to the field and orthogonal to the pump lamp light. The linear light after transversing the cell strikes an analyzer where it is converted to an intensity-modulated light. The modulated light is detected by a photodiode processed and utilized as feedback to control the field and pump lamp excitation and readout of angular displacement.

  7. Magnetic Resonance Safety

    PubMed Central

    Sammet, Steffen

    2016-01-01

    Magnetic Resonance Imaging (MRI) has a superior soft-tissue contrast compared to other radiological imaging modalities and its physiological and functional applications have led to a significant increase in MRI scans worldwide. A comprehensive MRI safety training to protect patients and other healthcare workers from potential bio-effects and risks of the magnetic fields in an MRI suite is therefore essential. The knowledge of the purpose of safety zones in an MRI suite as well as MRI appropriateness criteria is important for all healthcare professionals who will work in the MRI environment or refer patients for MRI scans. The purpose of this article is to give an overview of current magnetic resonance safety guidelines and discuss the safety risks of magnetic fields in an MRI suite including forces and torque of ferromagnetic objects, tissue heating, peripheral nerve stimulation and hearing damages. MRI safety and compatibility of implanted devices, MRI scans during pregnancy and the potential risks of MRI contrast agents will also be discussed and a comprehensive MRI safety training to avoid fatal accidents in an MRI suite will be presented. PMID:26940331

  8. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Griffith, Robert; Larsen, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, design, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  9. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Larsen, Michael; Mirijanian, James

    2012-06-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation is concluding the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, and design basics of the NMRG including an overview of the NSD designs developed and demonstrated in the DARPA gyro development program. General performance results from phases 3 and 4 will also be presented.

  10. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael; Griffith, Robert; Bulatowicz, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This presentation will describe the operational principles, design basics, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  11. Ion cyclotron resonance cell

    DOEpatents

    Weller, Robert R.

    1995-01-01

    An ion cyclotron resonance cell having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions.

  12. Ion cyclotron resonance cell

    DOEpatents

    Weller, R.R.

    1995-02-14

    An ion cyclotron resonance cell is disclosed having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions. 5 figs.

  13. Tunable superconducting microstrip resonators

    NASA Astrophysics Data System (ADS)

    Adamyan, A. A.; Kubatkin, S. E.; Danilov, A. V.

    2016-04-01

    We report on a simple yet versatile design for a tunable superconducting microstrip resonator. Niobium nitride is employed as the superconducting material and aluminum oxide, produced by atomic layer deposition, as the dielectric layer. We show that the high quality of the dielectric material allows to reach the internal quality factors in the order of Qi˜104 in the single photon regime. Qi rapidly increases with the number of photons in the resonator N and exceeds 105 for N ˜10 -50 . A straightforward modification of the basic microstrip design allows to pass a current bias through the strip and to control its kinetic inductance. We achieve a frequency tuning δf =62 MHz around f0=2.4 GHz for a fundamental mode and δf =164 MHz for a third harmonic. This translates into a tuning parameter Qiδf /f0=150 . The presented design can be incorporated into essentially any superconducting circuitry operating at temperatures below 2.5 K.

  14. A mirrorless spinwave resonator

    PubMed Central

    Pinel, Olivier; Everett, Jesse L.; Hosseini, Mahdi; Campbell, Geoff T.; Buchler, Ben C.; Lam, Ping Koy

    2015-01-01

    Optical resonance is central to a wide range of optical devices and techniques. In an optical cavity, the round-trip length and mirror reflectivity can be chosen to optimize the circulating optical power, linewidth, and free-spectral range (FSR) for a given application. In this paper we show how an atomic spinwave system, with no physical mirrors, can behave in a manner that is analogous to an optical cavity. We demonstrate this similarity by characterising the build-up and decay of the resonance in the time domain, and measuring the effective optical linewidth and FSR in the frequency domain. Our spinwave is generated in a 20 cm long Rb gas cell, yet it facilitates an effective FSR of 83 kHz, which would require a round-trip path of 3.6 km in a free-space optical cavity. Furthermore, the spinwave coupling is controllable enabling dynamic tuning of the effective cavity parameters. PMID:26655839

  15. DISSIPATIVE DIVERGENCE OF RESONANT ORBITS

    SciTech Connect

    Batygin, Konstantin; Morbidelli, Alessandro

    2013-01-01

    A considerable fraction of multi-planet systems discovered by the observational surveys of extrasolar planets reside in mild proximity to first-order mean-motion resonances. However, the relative remoteness of such systems from nominal resonant period ratios (e.g., 2:1, 3:2, and 4:3) has been interpreted as evidence for lack of resonant interactions. Here, we show that a slow divergence away from exact commensurability is a natural outcome of dissipative evolution and demonstrate that libration of critical angles can be maintained tens of percent away from nominal resonance. We construct an analytical theory for the long-term dynamical evolution of dissipated resonant planetary pairs and confirm our calculations numerically. Collectively, our results suggest that a significant fraction of the near-commensurate extrasolar planets are in fact resonant and have undergone significant dissipative evolution.

  16. Optical resonator and laser applications

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    The invention discloses a semi-ring Fabry-Perot (SRFP) optical resonator structure comprising a medium including an edge forming a reflective facet and a waveguide within the medium, the waveguide having opposing ends formed by the reflective facet. The performance of the SRFP resonator can be further enhanced by including a Mach-Zehnder interferometer in the waveguide on one side of the gain medium. The optical resonator can be employed in a variety of optical devices. Laser structures using at least one SRFP resonator are disclosed where the resonators are disposed on opposite sides of a gain medium. Other laser structures employing one or more resonators on one side of a gain region are also disclosed.

  17. Fermi resonance in optical microcavities

    NASA Astrophysics Data System (ADS)

    Yi, Chang-Hwan; Yu, Hyeon-Hye; Lee, Ji-Won; Kim, Chil-Min

    2015-04-01

    Fermi resonance is a phenomenon of quantum mechanical superposition, which most often occurs between normal and overtone modes in molecular systems that are nearly coincident in energy. We find that scarred resonances in deformed dielectric microcavities are the very phenomenon of Fermi resonance, that is, a pair of quasinormal modes interact with each other due to coupling and a pair of resonances are generated through an avoided resonance crossing. Then the quantum number difference of a pair of quasinormal modes, which is a consequence of quantum mechanical superposition, equals periodic orbits, whereby the resonances are localized on the periodic orbits. We derive the relation between the quantum number difference and the periodic orbits and confirm it in an elliptic, a rectangular, and a stadium-shaped dielectric microcavity.

  18. GAUSSIAN BEAM LASER RESONATOR PROGRAM

    NASA Technical Reports Server (NTRS)

    Cross, P. L.

    1994-01-01

    In designing a laser cavity, the laser engineer is frequently concerned with more than the stability of the resonator. Other considerations include the size of the beam at various optical surfaces within the resonator or the performance of intracavity line-narrowing or other optical elements. Laser resonators obey the laws of Gaussian beam propagation, not geometric optics. The Gaussian Beam Laser Resonator Program models laser resonators using Gaussian ray trace techniques. It can be used to determine the propagation of radiation through laser resonators. The algorithm used in the Gaussian Beam Resonator program has three major components. First, the ray transfer matrix for the laser resonator must be calculated. Next calculations of the initial beam parameters, specifically, the beam stability, the beam waist size and location for the resonator input element, and the wavefront curvature and beam radius at the input surface to the first resonator element are performed. Finally the propagation of the beam through the optical elements is computed. The optical elements can be modeled as parallel plates, lenses, mirrors, dummy surfaces, or Gradient Index (GRIN) lenses. A Gradient Index lens is a good approximation of a laser rod operating under a thermal load. The optical system may contain up to 50 elements. In addition to the internal beam elements the optical system may contain elements external to the resonator. The Gaussian Beam Resonator program was written in Microsoft FORTRAN (Version 4.01). It was developed for the IBM PS/2 80-071 microcomputer and has been implemented on an IBM PC compatible under MS DOS 3.21. The program was developed in 1988 and requires approximately 95K bytes to operate.

  19. Resonance capture and Saturn's rings

    SciTech Connect

    Patterson, C.W.

    1986-05-01

    We have assigned the resonances apparently responsible for the stabilization of the Saturn's shepherd satellites and for the substructure seen in the F-ring and the ringlets in the C-ring. We show that Saturn's narrow ringlets have a substructure determined by three-body resonances with Saturn's ringmoons and the sun. We believe such resonances have important implications to satellite formation. 17 refs., 1 fig., 1 tab.

  20. Coupled resonator vertical cavity laser

    SciTech Connect

    Choquette, K.D.; Chow, W.W.; Hou, H.Q.; Geib, K.M.; Hammons, B.E.

    1998-01-01

    The monolithic integration of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. The authors report the first electrically injected coupled resonator vertical-cavity laser diode and demonstrate novel characteristics arising from the cavity coupling, including methods for external modulation of the laser. A coupled mode theory is used model the output modulation of the coupled resonator vertical cavity laser.