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Sample records for absorptions exploiting photo-thermal

  1. Photo, thermal and chemical degradation of riboflavin

    PubMed Central

    Kazi, Sadia Hafeez; Ahmed, Sofia; Anwar, Zubair; Ahmad, Iqbal

    2014-01-01

    Summary Riboflavin (RF), also known as vitamin B2, belongs to the class of water-soluble vitamins and is widely present in a variety of food products. It is sensitive to light and high temperature, and therefore, needs a consideration of these factors for its stability in food products and pharmaceutical preparations. A number of other factors have also been identified that affect the stability of RF. These factors include radiation source, its intensity and wavelength, pH, presence of oxygen, buffer concentration and ionic strength, solvent polarity and viscosity, and use of stabilizers and complexing agents. A detailed review of the literature in this field has been made and all those factors that affect the photo, thermal and chemical degradation of RF have been discussed. RF undergoes degradation through several mechanisms and an understanding of the mode of photo- and thermal degradation of RF may help in the stabilization of the vitamin. A general scheme for the photodegradation of RF is presented. PMID:25246959

  2. Adaptive laser conditioning of reflective thin film based on photo thermal lens probe

    NASA Astrophysics Data System (ADS)

    Liu, Zhichao; Zheng, Yi; Zhang, Qinghua; Pan, Feng; Wei, Yaowei; Wang, Jian; Xu, Qiao

    2017-12-01

    A novel laser conditioning (LC) concept that performs adaptive control of exposure fluence is proposed. As photo-thermal absorption effect can discover defects responsible for laser-induced damage of reflective thin film, in situ photo-thermal lens probe is introduced in conventional LC procedure to detect defects during raster-scanning. The absorptance signal is fed back to guide the adaptive control of exposure fluence. By this method, the damage risk accompanying with LC can be reduced to a rather low level. In order to test the performance of adaptive laser conditioning (ALC), an experimental setup has been built, and several film samples have been tested. The results show that ALC is effective at reducing laser damage risk.

  3. Photo-thermal processing of semiconductor fibers and thin films

    NASA Astrophysics Data System (ADS)

    Gupta, Nishant

    Furnace processing and rapid thermal processing (RTP) have been an integral part of several processing steps in semiconductor manufacturing. The performance of RTP techniques can be improved many times by exploiting quantum photo-effects of UV and vacuum ultraviolet (VUV) photons in thermal processing and this technique is known as rapid photo-thermal processing (RPP). As compared to furnace processing and RTP, RPP provides higher diffusion coefficient, lower stress and lower microscopic defects. In this work, a custom designed automated photo assisted processing system was built from individual parts and an incoherent light source. This photo-assisted processing system is used to anneal silica clad silicon fibers and deposit thin-films. To the best of our knowledge, incoherent light source based rapid photo-thermal processing (RPP) was used for the first time to anneal glass-clad silicon core optical fibers. X-ray diffraction examination, Raman spectroscopy and electrical measurements showed a considerable enhancement of structural and crystalline properties of RPP treated silicon fibers. Photons in UV and vacuum ultraviolet (VUV) regions play a very important role in improving the bulk and carrier transport properties of RPP-treated silicon optical fibers, and the resultant annealing permits a path forward to in situ enhancement of the structure and properties of these new crystalline core optical fibers. To explore further applications of RPP, thin-films of Calcium Copper Titanate (CaCu3Ti4O12) or CCTO and Copper (I) Oxide (Cu2O) were also deposited using photo-assisted metal-organic chemical vapor deposition (MOCVD) on Si/SiO2 and n-Si substrate respectively. CCTO is one of the most researched giant dielectric constant materials in recent years. The given photo-assisted MOCVD approach provided polycrystalline CCTO growth on a SiO2 surface with grain sizes as large as 410 nm. Copper (I) oxide (Cu2O) is a direct band gap semiconductor with p-type conductivity and

  4. Graphene/elastomer composite-based photo-thermal nanopositioners

    PubMed Central

    Loomis, James; Fan, Xiaoming; Khosravi, Farhad; Xu, Peng; Fletcher, Micah; Cohn, Robert W.; Panchapakesan, Balaji

    2013-01-01

    The addition of nanomaterials to polymers can result not only in significant material property improvements, but also assist in creating entirely new composite functionalities. By dispersing graphene nanoplatelets (GNPs) within a polydimethylsiloxane matrix, we show that efficient light absorption by GNPs and subsequent energy transduction to the polymeric chains can be used to controllably produce significant amounts of motion through entropic elasticity of the pre-strained composite. Using dual actuators, a two-axis sub-micron resolution stage was developed, and allowed for two-axis photo-thermal positioning (~100 μm per axis) with 120 nm resolution (feedback sensor limitation), and ~5 μm/s actuation speeds. A PID control loop automatically stabilizes the stage against thermal drift, as well as random thermal-induced position fluctuations (up to the bandwidth of the feedback and position sensor). Maximum actuator efficiency values of ~0.03% were measured, approximately 1000 times greater than recently reported for light-driven polymer systems. PMID:23712601

  5. Advances in photo-thermal infrared imaging microspectroscopy

    NASA Astrophysics Data System (ADS)

    Furstenberg, Robert; Kendziora, Chris; Papantonakis, Michael; Nguyen, Viet; McGill, Andrew

    2013-05-01

    There is a growing need for chemical imaging techniques in many fields of science and technology: forensics, materials science, pharmaceutical and chemical industries, just to name a few. While FTIR micro-spectroscopy is commonly used, its practical resolution limit of about 20 microns or more is often insufficient. Raman micro-spectroscopy provides better spatial resolution (~1 micron), but is not always practical because of samples exhibiting fluorescence or low Raman scattering efficiency. We are developing a non-contact and non-destructive technique we call photo-thermal infrared imaging spectroscopy (PT-IRIS). It involves photo-thermal heating of the sample with a tunable quantum cascade laser and measuring the resulting increase in thermal emission with an infrared detector. Photo-thermal emission spectra resemble FTIR absorbance spectra and can be acquired in both stand-off and microscopy configurations. Furthermore, PT-IRIS allows the acquisition of absorbance-like photo-thermal spectra in a reflected geometry, suitable for field applications and for in-situ study of samples on optically IR-opaque substrates (metals, fabrics, paint, glass etc.). Conventional FTIR microscopes in reflection mode measure the reflectance spectra which are different from absorbance spectra and are usually not catalogued in FTIR spectral libraries. In this paper, we continue developing this new technique. We perform a series of numerical simulations of the laser heating of samples during photo-thermal microscopy. We develop parameterized formulas to help the user pick the appropriate laser illumination power. We also examine the influence of sample geometry on spectral signatures. Finally, we measure and compare photo-thermal and reflectance spectra for two test samples.

  6. Millisecond ordering of block-copolymer films via photo-thermal gradients

    DOE PAGES

    Majewski, Pawel W.; Yager, Kevin G.

    2015-03-12

    For the promise of self-assembly to be realized, processing techniques must be developed that simultaneously enable control of the nanoscale morphology, rapid assembly, and, ideally, the ability to pattern the nanostructure. Here, we demonstrate how photo-thermal gradients can be used to control the ordering of block-copolymer thin films. Highly localized laser heating leads to intense thermal gradients, which induce a thermophoretic force on morphological defects. This increases the ordering kinetics by at least 3 orders-of-magnitude, compared to conventional oven annealing. By simultaneously exploiting the thermal gradients to induce shear fields, we demonstrate uniaxial alignment of a block-copolymer film in lessmore » than a second. Finally, we provide examples of how control of the incident light-field can be used to generate prescribed configurations of block-copolymer nanoscale patterns.« less

  7. Laser-induced photo-thermal strain imaging

    NASA Astrophysics Data System (ADS)

    Choi, Changhoon; Ahn, Joongho; Jeon, Seungwan; Kim, Chulhong

    2018-02-01

    Vulnerable plaque is the one of the leading causes of cardiovascular disease occurrence. However, conventional intravascular imaging techniques suffer from difficulty in finding vulnerable plaque due to limitation such as lack of physiological information, imaging depth, and depth sensitivity. Therefore, new techniques are needed to help determine the vulnerability of plaque, Thermal strain imaging (TSI) is an imaging technique based on ultrasound (US) wave propagation speed that varies with temperature of medium. During temperature increase, strain occurs in the medium and its variation tendency is depending on the type of tissue, which makes it possible to use for tissue differentiation. Here, we demonstrate laser-induced photo-thermal strain imaging (pTSI) to differentiate tissue using an intravascular ultrasound (IVUS) catheter and a 1210-nm continuous-wave laser for heating lipids intensively. During heating, consecutive US images were obtained from a custom-made phantom made of porcine fat and gelatin. A cross correlation-based speckle-tracking algorithm was then applied to calculate the strain of US images. In the strain images, the positive strain produced in lipids (porcine fat) was clearly differentiated from water-bearing tissue (gelatin). This result shows that laser-induced pTSI could be a new method to distinguish lipids in the plaque and can help to differentiate vulnerability of plaque.

  8. Photo-thermal quartz tuning fork excitation for dynamic mode atomic force microscope

    SciTech Connect

    Bontempi, Alexia; Teyssieux, Damien; Thiery, Laurent

    2014-10-13

    A photo-thermal excitation of a Quartz Tuning Fork (QTF) for topographic studies is introduced. The non-invasive photo-thermal excitation presents practical advantages compared to QTF mechanical and electrical excitations, including the absence of the anti-resonance and its associated phase rotation. Comparison between our theoretical model and experiments validate that the optical transduction mechanism is a photo-thermal rather than photo-thermoacoustic phenomenon. Topographic maps in the context of near-field microscopy distance control have been achieved to demonstrate the performance of the system.

  9. Image processing with the radial Hilbert transform of photo-thermal imaging for carious detection

    NASA Astrophysics Data System (ADS)

    El-Sharkawy, Yasser H.

    2014-03-01

    Knowledge of heat transfer in biological bodies has many diagnostic and therapeutic applications involving either raising or lowering of temperature, and often requires precise monitoring of the spatial distribution of thermal histories that are produced during a treatment protocol. The present paper therefore aims to design and implementation of laser therapeutic and imaging system used for carious tracking and drilling by develop a mathematical algorithm using Hilbert transform for edge detection of photo-thermal imaging. photothermal imaging has the ability to penetrate and yield information about an opaque medium well beyond the range of conventional optical imaging. Owing to this ability, Q- switching Nd:YAG laser at wavelength 1064 nm has been extensively used in human teeth to study the sub-surface deposition of laser radiation. The high absorption coefficient of the carious rather than normal region rise its temperature generating IR thermal radiation captured by high resolution thermal camera. Changing the pulse repetition frequency of the laser pulses affects the penetration depth of the laser, which can provide three-dimensional (3D) images in arbitrary planes and allow imaging deep within a solid tissue.

  10. Near Infrared Fluorescence Imaging in Nano-Therapeutics and Photo-Thermal Evaluation

    PubMed Central

    Vats, Mukti; Mishra, Sumit Kumar; Baghini, Mahdieh Shojaei; Chauhan, Deepak S.; Srivastava, Rohit; De, Abhijit

    2017-01-01

    The unresolved and paramount challenge in bio-imaging and targeted therapy is to clearly define and demarcate the physical margins of tumor tissue. The ability to outline the healthy vital tissues to be carefully navigated with transection while an intraoperative surgery procedure is performed sets up a necessary and under-researched goal. To achieve the aforementioned objectives, there is a need to optimize design considerations in order to not only obtain an effective imaging agent but to also achieve attributes like favorable water solubility, biocompatibility, high molecular brightness, and a tissue specific targeting approach. The emergence of near infra-red fluorescence (NIRF) light for tissue scale imaging owes to the provision of highly specific images of the target organ. The special characteristics of near infra-red window such as minimal auto-fluorescence, low light scattering, and absorption of biomolecules in tissue converge to form an attractive modality for cancer imaging. Imparting molecular fluorescence as an exogenous contrast agent is the most beneficial attribute of NIRF light as a clinical imaging technology. Additionally, many such agents also display therapeutic potentials as photo-thermal agents, thus meeting the dual purpose of imaging and therapy. Here, we primarily discuss molecular imaging and therapeutic potentials of two such classes of materials, i.e., inorganic NIR dyes and metallic gold nanoparticle based materials. PMID:28452928

  11. An ultra-fast optical shutter exploiting total light absorption in a phase change material

    NASA Astrophysics Data System (ADS)

    Jafari, Mohsen; Guo, L. Jay; Rais-Zadeh, Mina

    2017-02-01

    In this paper, we present an ultra-fast and high-contrast optical shutter with applications in atomic clock assemblies, integrated photonic systems, communication hardware, etc. The shutter design exploits the total light absorption phenomenon in a thin phase change (PC) material placed over a metal layer. The shutter switches between ON and OFF states by changing PC material phase and thus its refractive index. The PC material used in this work is Germanium Telluride (GeTe), a group IV-VI chalcogenide compound, which exhibits good optical contrast when switching from amorphous to crystalline state and vice versa. The stable phase changing behavior and reliability of GeTe and GeSbTe (GST) have been verified in optical memories and RF switches. Here, GeTe is used as it has a lower extinction coefficient in near-IR regions compared to GST. GeTe can be thermally transitioned between two phases by applying electrical pulses to an integrated heater. The memory behavior of GeTe results in zero static power consumption which is useful in applications requiring long time periods between switching activities. We previously demonstrated a meta-surface employing GeTe in sub-wavelength slits with >14 dB isolation at 1.5 μm by exciting the surface plasmon polariton and localized slit resonances. In this work, strong interference effects in a thin layer of GeTe over a gold mirror result in near total light absorption of up to 40 dB (21 dB measured) in the amorphous phase of the shutter at 780 nm with much less fabrication complexity. The optical loss at the shutter ON state is less than 1.5 dB. A nickel chrome (NiCr) heater provides the Joule heating energy required to achieve the crystallographic phase change. The measured switching speed is 2 μs.

  12. Photo-thermal modulation of surface plasmon polariton propagation at telecommunication wavelengths.

    PubMed

    Kaya, S; Weeber, J-C; Zacharatos, F; Hassan, K; Bernardin, T; Cluzel, B; Fatome, J; Finot, C

    2013-09-23

    We report on photo-thermal modulation of thin film surface plasmon polaritons (SPP) excited at telecom wavelengths and traveling at a gold/air interface. By operating a modulated continuous-wave or a Q-switched nanosecond pump laser, we investigate the photo-thermally induced modulation of SPP propagation mediated by the temperature-dependent ohmic losses in the gold film. We use a fiber-to-fiber characterization set-up to measure accurately the modulation depth of the SPP signal under photo-thermal excitation. On the basis of these measurements, we extract the thermo-plasmonic coefficient of the SPP mode defined as the temperature derivative of the SPP damping constant. Next, we introduce a figure of merit which is relevant to characterize the impact of temperature onto the properties of bounded or weakly leaky SPP modes supported by a given metal at a given wavelength. By combining our measurements with tabulated values of the temperature-dependent imaginary part of gold dielectric function, we compute the thermo-optical coefficients (TOC) of gold at telecom wavelengths. Finally, we investigate a pulsed photo-thermal excitation of the SPP in the nanosecond regime. The experimental SPP depth of modulation obtained in this situation are found to be in fair agreement with the modulation depths computed by using our values of gold TOC.

  13. Photo-thermal characteristics of water-based Fe3O4@SiO2 nanofluid for solar-thermal applications

    NASA Astrophysics Data System (ADS)

    Khashan, Saud; Dagher, Sawsan; Omari, Salahaddin Al; Tit, Nacir; Elnajjar, Emad; Mathew, Bobby; Hilal-Alnaqbi, Ali

    2017-05-01

    This work proposes and demonstrates the novel idea of using Fe3O4@SiO2 core/shell structure nanoparticles (NPs) to improve the solar thermal conversion efficiency. Magnetite (Fe3O4) NPs are synthesized by controlled co-precipitation method. Fe3O4@SiO2 NPs are prepared based on sol-gel approach, then characterized. Water-based Fe3O4@SiO2 nanofluid is prepared and usedto illustrate the photo-thermal conversion characteristics of a solar collector under solar simulator. The temperature rise characteristics of the nanofluids are investigated at different heights of the solar collector, for duration of 300 min, under a solar intensity of 1000 W m-2. The experimental results show that Fe3O4@SiO2 NPs have a core/shell structure with spherical morphology and size of about 400 nm. Fe3O4@SiO2/H2O nanofluid enhances the photo-thermal conversion efficiency compared with base fluid and Fe3O4/H2O nanofluid, since the silica coating improves both the thermodynamic stability of the nanofluid and the light absorption effectiveness of the NPs. At a concentration of 1 mg/1 ml of Fe3O4@SiO2/H2O, and with the utilization of kerosene into the solar collector, and exposure for radiation for 5 min, the photo-thermal conversion efficiency has shown an enhancement at the bottom of the collector of about 32.9% compared to the base fluid.

  14. Exploiting absorption-induced self-heating in solar cells (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Ullbrich, Sascha; Fischer, Axel; Erdenebileg, Enkhtur; Koerner, Christian; Reineke, Sebastian; Leo, Karl; Vandewal, Koen

    2017-04-01

    Absorption of light inevitably leads to a self-heating of each type of solar cell, either due to the excess energy of absorbed photons or non-radiative recombination of charge carriers. Although the effect of temperature on solar cell parameters such as the open-circuit voltage are well known, it is often ignored in Suns-Voc measurements [1]. This measurement technique enables direct access to the diode ideality factor without an influence by series resistance. A frequently seen decrease of the ideality factor or a saturation of the open-circuit voltage at high illumination intensities is often attributed solely to surface recombination [2], the shape of the density of states (DOS) [3], or the quality of the back contact in inorganic solar cells [4]. In this work, we present an analytical model for taking into account absorption induced self-heating in Suns-Voc measurements and validate it for various solar cell technologies such as small molecule organic solar cells, perovskite solar cells, and inorganic solar cells. Furthermore, with an adapted Suns-Voc technique, we are able to not only correctly determine the ideality factor, but also the relevant energy gap of the solar cell, which is especially of interest in the field of novel solar cell technologies. [1] R.A. Sinton and A. Cuevas, EU PVSEC, 1152-1155 (2000) [2] K. Tvingstedt and C. Deibel, Adv. Energy Mater. 6, 1502230 (2016) [3] T. Kirchartz and J. Nelson, Phys. Rev. B 86, 165201 (2012) [4] S. Glunz, J. Nekarda, H. Maeckel et al., EU PVSEC, 849-853 (2007)

  15. Character of skin on photo-thermal response and its regeneration process using second-harmonic generation microscopy.

    PubMed

    Wu, Shu-lian; Li, Hui; Zhang, Xiao-man; Chen, Wei R; Wang, Yun-Xia

    2014-01-01

    Quantitative characterization of skin collagen on photo-thermal response and its regeneration process is an important but difficult task. In this study, morphology and spectrum characteristics of collagen during photo-thermal response and its light-induced remodeling process were obtained by second-harmonic generation microscope in vivo. The texture feature of collagen orientation index and fractal dimension was extracted by image processing. The aim of this study is to detect the information hidden in skin texture during the process of photo-thermal response and its regeneration. The quantitative relations between injured collagen and texture feature were established for further analysis of the injured characteristics. Our results show that it is feasible to determine the main impacts of phototherapy on the skin. It is important to understand the process of collagen remodeling after photo-thermal injuries from texture feature.

  16. Sub-100 nm Gold Nanomatryoshkas Improve Photo-thermal Therapy Efficacy in Large and Highly Aggressive Triple Negative Breast Tumors

    PubMed Central

    Bishnoi, Sandra; Urban, Alexander; Charron, Heather; Mitchell, Tamika; Shea, Martin; Nanda, Sarmistha; Schiff, Rachel; Halas, Naomi; Joshi, Amit

    2014-01-01

    There is an unmet need for efficient near-infrared photothermal transducers for the treatment of highly aggressive cancers and large tumors where the penetration of light can be substantially reduced, and the intra-tumoral nanoparticle transport is restricted due to the presence of hypoxic or nectrotic regions. We report the performance advantages obtained by sub 100 nm gold nanomatryushkas, comprising of concentric gold-silica-gold layers compared to conventional ~150 nm silica core gold nanoshells for photothermal therapy of triple negative breast cancer. We demonstrate that a 33% reduction in silica-core-gold-shell nanoparticle size, while retaining near-infrared plasmon resonance, and keeping the nanoparticle surface charge constant, results in a four to five fold tumor accumulation of nanoparticles following equal dose of injected gold for both sizes. The survival time of mice bearing large (>1000 mm3) and highly aggressive triple negative breast tumors is doubled for the nanomatryushka treatment group under identical photo-thermal therapy conditions. The higher absorption cross-section of a nanomatryoshka results in a higher efficiency of photonic to thermal energy conversion and coupled with 4-5X accumulation within large tumors results in superior therapy efficacy. PMID:25051221

  17. Lattice parameter evolution in Pt nanoparticles during photo-thermally induced sintering and grain growth

    DOE PAGES

    Kelly, B.G.; Loether, A.; DiChiara, A. D.; ...

    2017-04-20

    An in-situ optical pump/x-ray probe technique has been used to study the size dependent lattice parameter of Pt nanoparticles subjected to picosecond duration optical laser pulses. The as-prepared Pt nanoparticles exhibited a contracted lattice parameter consistent with the response of an isolated elastic sphere to a compressive surface stress. During photo-thermally induced sintering and grain growth, however, the Pt lattice parameter did not evolve with the inverse particle size dependence predicted by simple surface stress models. Lastly, the observed behavior could be attributed to the combined effects of a compressive surface/interface stress and a tensile stress arising from intergranular material.

  18. Phase lag deduced information in photo-thermal actuation for nano-mechanical systems characterization

    SciTech Connect

    Bijster, R. J. F., E-mail: roy.bijster@tno.nl; Vreugd, J. de; Sadeghian, H.

    2014-08-18

    In photo-thermal actuation, heat is added locally to a micro-cantilever by means of a laser. A fraction of the irradiation is absorbed, yielding thermal stresses and deformations in the structure. Harmonic modulation of the laser power causes the cantilever to oscillate. Moreover, a phase lag is introduced which is very sensitive to the spot location and the cantilever properties. This phase lag is theoretically predicted and experimentally verified. Combined with thermo-mechanical properties of the cantilever and its geometry, the location of the laser spot, the thermal diffusivity, and the layer thicknesses of the cantilever can be extracted.

  19. Lattice parameter evolution in Pt nanoparticles during photo-thermally induced sintering and grain growth

    SciTech Connect

    Kelly, B.G.; Loether, A.; DiChiara, A. D.

    An in-situ optical pump/x-ray probe technique has been used to study the size dependent lattice parameter of Pt nanoparticles subjected to picosecond duration optical laser pulses. The as-prepared Pt nanoparticles exhibited a contracted lattice parameter consistent with the response of an isolated elastic sphere to a compressive surface stress. During photo-thermally induced sintering and grain growth, however, the Pt lattice parameter did not evolve with the inverse particle size dependence predicted by simple surface stress models. Lastly, the observed behavior could be attributed to the combined effects of a compressive surface/interface stress and a tensile stress arising from intergranular material.

  20. Photodetector based on Vernier-Enhanced Fabry-Perot Interferometers with a Photo-Thermal Coating

    PubMed Central

    Chen, George Y.; Wu, Xuan; Liu, Xiaokong; Lancaster, David G.; Monro, Tanya M.; Xu, Haolan

    2017-01-01

    We present a new type of fiber-coupled photodetector with a thermal-based optical sensor head, which enables it to operate even in the presence of strong electro-magnetic interference and in electrically sensitive environments. The optical sensor head consists of three cascaded Fabry-Perot interferometers. The end-face surface is coated with copper-oxide micro-particles embedded in hydrogel, which is a new photo-thermal coating that can be readily coated on many different surfaces. Under irradiation, photons are absorbed by the photo-thermal coating, and are converted into heat, changing the optical path length of the probing light and induces a resonant wavelength shift. For white-light irradiation, the photodetector exhibits a power sensitivity of 760 pm/mW, a power detection limit of 16.4 μW (i.e. specific detectivity of 2.2 × 105 cm.√Hz/W), and an optical damage threshold of ~100 mW or ~800 mW/cm2. The response and recovery times are 3.0 s (~90% of change within 100 ms) and 16.0 s respectively. PMID:28139745

  1. Enhanced Radiotherapy using Bismuth Sulfide Nanoagents Combined with Photo-thermal Treatment.

    PubMed

    Cheng, Xiaju; Yong, Yuan; Dai, Yiheng; Song, Xin; Yang, Gang; Pan, Yue; Ge, Cuicui

    2017-01-01

    Nanotechniques that can improve the effectiveness of radiotherapy (RT) by integrating it with multimodal imaging are highly desirable. Results In this study, we fabricated Bi 2 S 3 nanorods that have attractive features such as their ability to function as contrast agents for X-ray computed tomography (CT) and photoacoustic (PA) imaging as well as good biocompatibility. Both in vitro and in vivo studies confirmed that the Bi 2 S 3 nanoagents could potentiate the lethal effects of radiation via amplifying the local radiation dose and enhancing the anti-tumor efficacy of RT by augmenting the photo-thermal effect. Furthermore, the nanoagent-mediated hyperthermia could effectively increase the oxygen concentration in hypoxic regions thereby inhibiting the expression of hypoxia-inducible factor ( HIF -1α). This, in turn, interfered with DNA repair via decreasing the expression of DNA repair-related proteins to overcome radio-resistance. Also, RT combined with nanoagent-mediated hyperthermia could substantially suppress tumor metastasis via down-regulating angiogenic factors. Conclusion In summary, we constructed a single-component powerful nanoagent for CT/PA imaging-guided tumor radiotherapy and, most importantly, explored the potential mechanisms of nanoagent-mediated photo-thermal treatment for enhancing the efficacy of RT in a synergistic manner.

  2. Modification of a neuronal network direction using stepwise photo-thermal etching of an agarose architecture.

    PubMed

    Suzuki, Ikurou; Sugio, Yoshihiro; Moriguchi, Hiroyuki; Jimbo, Yasuhiko; Yasuda, Kenji

    2004-07-01

    Control over spatial distribution of individual neurons and the pattern of neural network provides an important tool for studying information processing pathways during neural network formation. Moreover, the knowledge of the direction of synaptic connections between cells in each neural network can provide detailed information on the relationship between the forward and feedback signaling. We have developed a method for topographical control of the direction of synaptic connections within a living neuronal network using a new type of individual-cell-based on-chip cell-cultivation system with an agarose microchamber array (AMCA). The advantages of this system include the possibility to control positions and number of cultured cells as well as flexible control of the direction of elongation of axons through stepwise melting of narrow grooves. Such micrometer-order microchannels are obtained by photo-thermal etching of agarose where a portion of the gel is melted with a 1064-nm infrared laser beam. Using this system, we created neural network from individual Rat hippocampal cells. We were able to control elongation of individual axons during cultivation (from cells contained within the AMCA) by non-destructive stepwise photo-thermal etching. We have demonstrated the potential of our on-chip AMCA cell cultivation system for the controlled development of individual cell-based neural networks.

  3. Photo-thermal characteristics of hybrid nanofluids based on Therminol-55 oil for concentrating solar collectors

    NASA Astrophysics Data System (ADS)

    Gulzar, Ovais; Qayoum, Adnan; Gupta, Rajat

    2018-03-01

    Hybrid nanofluids are the new generation efficient heat transfer fluids allowing greater control over the properties of base fluid as compared to mono-nanofluids. In this study, attempt has been made for increasing the efficiency for photo-thermal conversion by heat transfer fluid for high temperature solar collectors. Therminol-55, a high temperature heat transfer fluid is doped with Al2O3 and TiO2 nanoparticles with an aim to improve the thermal and optical properties. Effects of concentration and type of nanoparticle on photo-thermal conversion properties and absorbance in Therminol-55 have been studied. Spectrophotometric analysis has been carried for all nanofluids, namely, Al2O3-Therminol-55, TiO2-Therminol-55 and hybrid (Al2O3-TiO2)-Therminol-55 nanofluids with varying concentrations of 0.05, 0.075, 0.1, 0.25, 0.5 wt%. It was found that TiO2 nanofluids possess the maximum absorbance with minimal effect of nanoparticle concentration above 0.1 wt% followed by hybrid (Al2O3-TiO2) nanofluid (HNF) with strong dependence of concentration. Al2O3-Therminol-55 nanofluids exhibited least absorbance. The peak values of absorbance are 0.47, 2.15 and 2.144 in the visible region for Al2O3-Therminol-55, TiO2-Therminol-55 and hybrid (Al2O3-TiO2)-Therminol-55 nanofluids, respectively. It was observed that hybrid nanofluids show both bathochromic and hyperchromic shifts. Further, performance testing has been carried out using artificial source of light and it has been observed that hybrid nanofluids provide efficient photo-thermal conversion as compared to TiO2 and Al2O3-Therminol-55 nanofluids. Maximum temperatures of 152.9, 149.6, 158.6 °C were observed for 0.5 wt% Al2O3-Therminol-55, 0.1 wt% TiO2-Therminol-55, and 0.5 wt% hybrid (Al2O3-TiO2) nanofluid, respectively, against 125.8 °C of Therminol-55. Hybrid nanofluids based on Therminol-55 could be a potential candidate for high temperature concentrating collectors based on the superior properties over mono-nanofluids and

  4. Surface Chemistry Manipulation of Gold Nanorods Displays High Cellular Uptake In Vitro While Preserving Optical Properties for Bio-Imaging and Photo-Thermal Applications

    DTIC Science & Technology

    2016-03-28

    PROPERTIES FOR BIO -IMAGING AND PHOTO-THERMAL APPLICATIONS ANTHONY B. POLITO III, Maj, USAF, BSC, PhD, MT(ASCP)SBB March 2016 Final Report for March...HIGH CELLULAR UPTAKE IN VITRO WHILE PRESERVING OPTICAL PROPERTIES FOR BIO -IMAGING AND PHOTO-THERMAL APPLICATIONS. 5a. CONTRACT NUMBER 5b...These findings identify MTAB-TA GNRs as prime candidates for use in nano-based bio -imaging and photo-thermal applications. 15. SUBJECT TERMS

  5. Structural, optical and photo thermal properties of Er3+:Y2O3 doped PMMA nanocomposite

    NASA Astrophysics Data System (ADS)

    Tabanli, Sevcan; Eryurek, Gonul

    2018-02-01

    Thermal decomposition technique was employed to synthesize of phosphors of yttria (Y2O3) doped with erbium (Er3+) ions. After the synthesized procedure, the nano-sized crystalline powders were annealed at 800oC for 24 h. Annealed powders were embedded in poly(methyl methacrylate) (PMMA) by free radical polymerization to fabricate nanocomposite polymer materials. The crystalline structure of the powder and doped PMMA nanocomposite samples were determined using X-ray diffraction technique. Scherrer's equation and the FW1/5/4/5M method were used to determine average crystalline size and grain size distributions, respectively. The spectroscopic properties of the powders and doped PMMA nanocomposites were studied by measuring the upconversion emission spectra under near-infrared laser excitation at room temperature. The laser-induced photo thermal behaviors of Er3+:Y2O3 nano-powders and doped PMMA nanocomposite were investigated using the fluorescence intensity ratio (FIR) technique.

  6. Thermal and photo-thermal PROX reaction over Ag/SiO2 catalysts

    NASA Astrophysics Data System (ADS)

    Sabinas-Hernández, S. A.; Romero-Núñez, A.; Díaz, G.

    2018-02-01

    The effect of plasmonic excitation of Ag/SiO2 catalysts was studied in the preferential CO oxidation in presence of H2 (PROX) at low temperature. Catalysts with 5 wt% silver loading were prepared by wet impregnation in aqueous and basic media. TEM analysis indicates the presence of Ag nanoparticles with a broad particle size distribution which can achieve both, good PROX activity at low temperature and plasmonic interaction with visible light. Photo-assisted reaction at 35 °C enhance CO and O2 conversions; however, the greater improvement was found for O2 conversion. The selectivity towards CO2 decrease when reaction took place under photo-thermal conditions. Occurrence of different silver species and particle size changed after reaction as evidenced by DRS-UV-vis and TEM.

  7. Single-molecule detection of dihydroazulene photo-thermal reaction using break junction technique

    NASA Astrophysics Data System (ADS)

    Huang, Cancan; Jevric, Martyn; Borges, Anders; Olsen, Stine T.; Hamill, Joseph M.; Zheng, Jue-Ting; Yang, Yang; Rudnev, Alexander; Baghernejad, Masoud; Broekmann, Peter; Petersen, Anne Ugleholdt; Wandlowski, Thomas; Mikkelsen, Kurt V.; Solomon, Gemma C.; Brøndsted Nielsen, Mogens; Hong, Wenjing

    2017-05-01

    Charge transport by tunnelling is one of the most ubiquitous elementary processes in nature. Small structural changes in a molecular junction can lead to significant difference in the single-molecule electronic properties, offering a tremendous opportunity to examine a reaction on the single-molecule scale by monitoring the conductance changes. Here, we explore the potential of the single-molecule break junction technique in the detection of photo-thermal reaction processes of a photochromic dihydroazulene/vinylheptafulvene system. Statistical analysis of the break junction experiments provides a quantitative approach for probing the reaction kinetics and reversibility, including the occurrence of isomerization during the reaction. The product ratios observed when switching the system in the junction does not follow those observed in solution studies (both experiment and theory), suggesting that the junction environment was perturbing the process significantly. This study opens the possibility of using nano-structured environments like molecular junctions to tailor product ratios in chemical reactions.

  8. Photo-thermal and cytotoxic properties of inkjet-printed copper sulfide films on biocompatible latex coated substrates

    NASA Astrophysics Data System (ADS)

    Sarfraz, Jawad; Borzenkov, Mykola; Niemelä, Erik; Weinberger, Christian; Törngren, Björn; Rosqvist, Emil; Collini, Maddalena; Pallavicini, Piersandro; Eriksson, John; Peltonen, Jouko; Ihalainen, Petri; Chirico, Giuseppe

    2018-03-01

    Inkjet-printing of metal nanoparticles is a particularly promising technique for the fabrication and modification of surfaces with a multifunctional nature. Recently copper sulfide nanoparticles (CuS NPs) have attracted wide interest due to a range of valuable properties including long term stability, photo-thermal activity, ease of synthesis and low cost. In the present study, printed CuS patterns were successfully fabricated on latex coated paper substrates and characterized by means of atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR spectroscopy, and grazing incidence X-ray diffraction (GID). The resulted patterns displayed pronounced photo-thermal effect under Near Infrared Irradiation (NIR) even with relatively low laser power. Finally, by utilizing an automated real-time imaging platform it was possible to verify that the CuS printed film was not cytotoxic to human dermal fibroblast cells (HDF). The pronounced photo-thermal properties and nontoxic nature of these printed low-cost flexible CuS films make them promising candidates for fabrication of devices with localized photo-thermal effect suitable for biomedical applications.

  9. Active photo-thermal self-healing of shape memory polyurethanes

    NASA Astrophysics Data System (ADS)

    Kazemi-Lari, Mohammad A.; Malakooti, Mohammad H.; Sodano, Henry A.

    2017-05-01

    Structural health monitoring (SHM) has received significant interest over the past decade and has led to the development of a wide variety of sensors and signal processing techniques to determine the presence of changes or damage in a structural system. The topic has attracted significant attention due to the safety and performance enhancing benefits as well as the potential lifesaving capabilities offered by the technology. While the resulting systems are capable of sensing their surrounding structural and environmental conditions, few methods exist for using the information to autonomously react and repair or protect the system. One of the major challenges in the future implementation of SHM systems is their coupling with materials that can react to the damage to heal themselves and return to normal function. The coupling of self-healing materials with SHM has the potential to significantly prolong the lifetime of structural systems and extend the required inspection intervals. In the present study, an optical fiber based self-healing system composed of mendable polyurethanes based on the thermally reversible Diels-Alder (DA) reaction is developed. Inspired by health monitoring techniques, active photo-thermal sensing and actuation is achieved using infrared laser light passing through an optical fiber and a thermal power sensor to detect the presence of cracking in the structure. Healing is triggered as the crack propagates through the polymer and fractures the embedded optical fiber. Through a feedback loop, the detected power drop by the sensor is utilized as a signal to heat the cracked area and stimulate the shape memory effect of the polyurethane and the retro-DA reaction. The healing performance results indicate that this novel integrated system can be effectively employed to monitor the incidence of damage and actively heal a crack in the polymer.

  10. A novel modeling and simulation technique of photo--thermal interactions between lasers and living biological tissues undergoing multiple changes in phase.

    PubMed

    Dua, Rajan; Chakraborty, Suman

    2005-06-01

    Knowledge of heat transfer in biological bodies has many therapeutic applications involving either raising or lowering of temperature, and often requires precise monitoring of the spatial distribution of thermal histories that are produced during a treatment protocol. Extremes of temperature into the freezing and burning ranges are useful in surgical procedures for selective killing and/or removal of target tissues. For example, the primary objective of hyperthermia is to raise the temperature of the diseased tissue to a therapeutic value, typically 41- 44 degrees C, and then thermally destroy it. The present paper therefore aims to develop a mathematical model for effective simulation of photo--thermal interactions between laser rays and biological tissues. In particular, damage of biological tissues when subjected to single point laser diathermy is numerically investigated using a unique enthalpy-based approach for modeling multiple phase change, (namely, melting of fat and vaporization of water content of the tissues) and the associated release/absorption of latent heat in conjunction with unsteady state heat conduction mechanisms. The governing equations of bio-heat transfer coupled with initial and boundary conditions are solved using a finite volume approach in conjunction with line by a line tri-diagonal matrix algorithm (TDMA) solver. Temperature responses of tissues subject to laser heating are quantitatively investigated in detail using the present model, and the resultant solutions are expected to be immensely useful in a variety of Bio-thermal practices in medicine and surgery.

  11. A DPL model of photo-thermal interaction in an infinite semiconductor material containing a spherical hole

    NASA Astrophysics Data System (ADS)

    Hobiny, Aatef D.; Abbas, Ibrahim A.

    2018-01-01

    The dual phase lag (DPL) heat transfer model is applied to study the photo-thermal interaction in an infinite semiconductor medium containing a spherical hole. The inner surface of the cavity was traction free and loaded thermally by pulse heat flux. By using the eigenvalue approach methodology and Laplace's transform, the physical variable solutions are obtained analytically. The numerical computations for the silicon-like semiconductor material are obtained. The comparison among the theories, i.e., dual phase lag (DPL), Lord and Shulman's (LS) and the classically coupled thermoelastic (CT) theory is presented graphically. The results further show that the analytical scheme can overcome mathematical problems by analyzing these problems.

  12. Sensitive photo-thermal response of graphene oxide for mid-infrared detection

    NASA Astrophysics Data System (ADS)

    Bae, Jung Jun; Yoon, Jung Hyun; Jeong, Sooyeon; Moon, Byoung Hee; Han, Joong Tark; Jeong, Hee Jin; Lee, Geon-Woong; Hwang, Ha Ryong; Lee, Young Hee; Jeong, Seung Yol; Lim, Seong Chu

    2015-09-01

    This study characterizes the effects of incident infrared (IR) radiation on the electrical conductivity of graphene oxide (GO) and examines its potential for mid-IR detection. Analysis of the mildly reduced GO (m-GO) transport mechanism near room temperature reveals variable range hopping (VRH) for the conduction of electrons. This VRH behavior causes the m-GO resistance to exhibit a strong temperature dependence, with a large negative temperature coefficient of resistance of approximately -2 to -4% K-1. In addition to this hopping transport, the presence of various oxygen-related functional groups within GO enhances the absorption of IR radiation significantly. These two GO material properties are synergically coupled and provoke a remarkable photothermal effect within this material; specifically, a large resistance drop is exhibited by m-GO in response to the increase in temperature caused by the IR absorption. The m-GO bolometer effect identified in this study is different from that exhibited in vanadium oxides, which require added gold-black films that function as IR absorbers owing to their limited IR absorption capability.This study characterizes the effects of incident infrared (IR) radiation on the electrical conductivity of graphene oxide (GO) and examines its potential for mid-IR detection. Analysis of the mildly reduced GO (m-GO) transport mechanism near room temperature reveals variable range hopping (VRH) for the conduction of electrons. This VRH behavior causes the m-GO resistance to exhibit a strong temperature dependence, with a large negative temperature coefficient of resistance of approximately -2 to -4% K-1. In addition to this hopping transport, the presence of various oxygen-related functional groups within GO enhances the absorption of IR radiation significantly. These two GO material properties are synergically coupled and provoke a remarkable photothermal effect within this material; specifically, a large resistance drop is exhibited by m

  13. Plasmonic fluorescent CdSe/Cu2S hybrid nanocrystals for multichannel imaging and cancer directed photo-thermal therapy

    NASA Astrophysics Data System (ADS)

    Sheikh Mohamed, M.; Poulose, Aby Cheruvathoor; Veeranarayanan, Srivani; Romero Aburto, Rebecca; Mitcham, Trevor; Suzuki, Yuko; Sakamoto, Yasushi; Ajayan, Pulickel M.; Bouchard, Richard R.; Yoshida, Yasuhiko; Maekawa, Toru; Sakthi Kumar, D.

    2016-04-01

    A simple, crude Jatropha curcas (JC) oil-based synthesis approach, devoid of any toxic phosphine and pyrophoric ligands, to produce size and shape tuned CdSe QDs and a further copper sulfide (Cu2S) encasing is presented. The QDs exhibited excellent photoluminescent properties with narrow band gap emission. Furthermore, the Cu2S shell rendered additional cytocompatibility and stability to the hybrid nanomaterial, which are major factors for translational and clinical applications of QDs. The nanocomposites were PEGylated and folate conjugated to augment their cytoamiability and enhance their specificity towards cancer cells. The nanohybrids possess potentials for visible, near infrared (NIR), photoacoustic (PA) and computed tomography (μCT) imaging. The diverse functionality of the composite was derived from the multi-channel imaging abilities and thermal competence on NIR laser irradiation to specifically actuate the photo-thermal ablation of brain cancer cells.A simple, crude Jatropha curcas (JC) oil-based synthesis approach, devoid of any toxic phosphine and pyrophoric ligands, to produce size and shape tuned CdSe QDs and a further copper sulfide (Cu2S) encasing is presented. The QDs exhibited excellent photoluminescent properties with narrow band gap emission. Furthermore, the Cu2S shell rendered additional cytocompatibility and stability to the hybrid nanomaterial, which are major factors for translational and clinical applications of QDs. The nanocomposites were PEGylated and folate conjugated to augment their cytoamiability and enhance their specificity towards cancer cells. The nanohybrids possess potentials for visible, near infrared (NIR), photoacoustic (PA) and computed tomography (μCT) imaging. The diverse functionality of the composite was derived from the multi-channel imaging abilities and thermal competence on NIR laser irradiation to specifically actuate the photo-thermal ablation of brain cancer cells. Electronic supplementary information (ESI

  14. Combined chemo- and photo-thermal therapy delivered by multifunctional theranostic gold nanorod-loaded microcapsules

    NASA Astrophysics Data System (ADS)

    Chen, Haiyan; di, Yingfeng; Chen, Dan; Madrid, Kyle; Zhang, Min; Tian, Caiping; Tang, Liping; Gu, Yueqing

    2015-05-01

    A polyelectrolyte microcapsule-based, cancer-targeting, and controlled drug delivery system has been developed as a multifunctional theranostic agent for synergistic cancer treatment. This new system, called FA-MC@GNR, is composed of folic acid (FA)-modified, multi-layered, hollow microcapsules loaded with gold nanorods (GNRs), and undergoes thermal degradation under near infrared (NIR) light. Either an NIR dye (MPA) or anti-cancer drug (doxorubicin, DOX) was loaded into the microcapsules via physical adsorption, yielding FA-MC@GNRs/MPA or FA-MC@GNRs/DOX, both of which exhibit no obvious toxicity, high stability, and remarkably improved tumor-targeting capabilities in vivo. Utilizing the strong NIR absorption of FA-MC@GNRs/DOX, we demonstrate the system's ability to simultaneously elicit photothermal therapy and controlled chemotherapy, achieving synergistic cancer treatment both in vitro cellular and in vivo animal experiments. Our study presents a new type of multifunctional micro-carrier for the delivery of chemotherapeutic drugs and photothermal agents, which has been shown to be an effective therapeutic approach for combined cancer treatment.

  15. Optical planar waveguides in photo-thermal-refractive glasses fabricated by single- or double-energy carbon ion implantation

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Shen, Xiao-Liang; Zheng, Rui-Lin; Guo, Hai-Tao; Lv, Peng; Liu, Chun-Xiao

    2018-01-01

    Ion implantation has demonstrated to be an efficient and reliable technique for the fabrication of optical waveguides in a diversity of transparent materials. Photo-thermal-refractive glass (PTR) is considered to be durable and stable holographic recording medium. Optical planar waveguide structures in the PTR glasses were formed, for the first time to our knowledge, by the C3+-ion implantation with single-energy (6.0 MeV) and double-energy (5.5+6.0 MeV), respectively. The process of the carbon ion implantation was simulated by the stopping and range of ions in matter code. The morphologies of the waveguides were recorded by a microscope operating in transmission mode. The guided beam distributions of the waveguides were measured by the end-face coupling technique. Comparing with the single-energy implantation, the double-energy implantation improves the light confinement for the dark-mode spectrum. The guiding properties suggest that the carbon-implanted PTR glass waveguides have potential for the manufacture of photonic devices.

  16. Subsurface thermal behaviour of tissue mimics embedded with large blood vessels during plasmonic photo-thermal therapy.

    PubMed

    Paul, Anup; Narasimhan, Arunn; Das, Sarit K; Sengupta, Soujit; Pradeep, Thalappil

    2016-11-01

    The purpose of this study was to understand the subsurface thermal behaviour of a tissue phantom embedded with large blood vessels (LBVs) when exposed to near-infrared (NIR) radiation. The effect of the addition of nanoparticles to irradiated tissue on the thermal sink behaviour of LBVs was also studied. Experiments were performed on a tissue phantom embedded with a simulated blood vessel of 2.2 mm outer diameter (OD)/1.6 mm inner diameter (ID) with a blood flow rate of 10 mL/min. Type I collagen from bovine tendon and agar gel were used as tissue. Two different nanoparticles, gold mesoflowers (AuMS) and graphene nanostructures, were synthesised and characterised. Energy equations incorporating a laser source term based on multiple scattering theories were solved using finite element-based commercial software. The rise in temperature upon NIR irradiation was seen to vary according to the position of the blood vessel and presence of nanoparticles. While the maximum rise in temperature was about 10 °C for bare tissue, it was 19 °C for tissue embedded with gold nanostructures and 38 °C for graphene-embedded tissues. The axial temperature distribution predicted by computational simulation matched the experimental observations. A different subsurface temperature distribution has been obtained for different tissue vascular network models. The position of LBVs must be known in order to achieve optimal tissue necrosis. The simulation described here helps in predicting subsurface temperature distributions within tissues during plasmonic photo-thermal therapy so that the risks of damage and complications associated with in vivo experiments and therapy may be avoided.

  17. Photo-thermal reactions of ethanol over Ag/TiO2 catalysts. The role of silver plasmon resonance in the reaction kinetics.

    PubMed

    Nadeem, M A; Idriss, H

    2018-05-17

    Photo-thermal catalytic reactions of ethanol over Ag/TiO2 were conducted in order to probe into the role of plasmonic resonance response in the reaction kinetics. In the 300-500 K temperature domain the increase in reaction rate is found to be mainly due to changes in the activation energy while above this temperature range the increase was due to the pre-exponential factor. These results might be linked to the role of plasmonic Ag particles in polarising the reaction intermediates and therefore increasing the reaction products at temperatures up to about 500 K.

  18. Investigations of the possibility of determination of thermal parameters of Si and SiGe samples based on the Photo Thermal Radiometry technique

    NASA Astrophysics Data System (ADS)

    Chrobak, Ł.; Maliński, M.

    2018-03-01

    This paper presents results of investigations of the possibility of determination of thermal parameters (thermal conductivity, thermal diffusivity) of silicon and silicon germanium crystals from the frequency characteristics of the Photo Thermal Radiometry (PTR) signal. The theoretical analysis of the influence of the mentioned parameters on the PTR signal has been presented and discussed. The values of the thermal and recombination parameters have been extracted from the fittings of the theoretical to experimental data. The presented approach uses the reference Si sample whose thermal and recombination parameters are known.

  19. Exploiting simultaneous observational constraints on mass and absorption to estimate the global direct radiative forcing of black carbon and brown carbon

    NASA Astrophysics Data System (ADS)

    Wang, X.; Heald, C. L.; Ridley, D. A.; Schwarz, J. P.; Spackman, J. R.; Perring, A. E.; Coe, H.; Liu, D.; Clarke, A. D.

    2014-06-01

    Atmospheric black carbon (BC) is a leading climate warming agent, yet uncertainties on the global direct radiative forcing (DRF) remain large. Here we expand a global model simulation (GEOS-Chem) of BC to include the absorption enhancement associated with BC coating and separately treat both the aging and physical properties of fossil fuel and biomass burning BC. In addition we develop a global simulation of Brown Carbon (BrC) from both secondary (aromatic) and primary (biomass burning and biofuel) sources. The global mean lifetime of BC in this simulation (4.4 days) is substantially lower compared to the AeroCom I model means (7.3 days), and as a result, this model captures both the mass concentrations measured in near-source airborne field campaigns (ARCTAS, EUCAARI) and surface sites within 30%, and in remote regions (HIPPO) within a factor of two. We show that the new BC optical properties together with the inclusion of BrC reduces the model bias in Absorption Aerosol Optical Depth (AAOD) at multiple wavelengths by more than 50% at AERONET sites worldwide. However our improved model still underestimates AAOD by a factor of 1.4 to 2.8 regionally, with largest underestimates in regions influenced by fire. Using the RRTMG model integrated with GEOS-Chem we estimate that the all-sky top-of-atmosphere DRF of BC is +0.13 W m-2 (0.08 W m-2 from anthropogenic sources and 0.05 W m-2 from biomass burning). If we scale our model to match AERONET AAOD observations we estimate the DRF of BC is +0.21 W m-2, with an additional +0.11 W m-2 of warming from BrC. Uncertainties in size, optical properties, observations, and emissions suggest an overall uncertainty in BC DRF of -80% / +140%. Our estimates are at the lower end of the 0.2-1.0 W m-2 range from previous studies, and substantially less than the +0.6 W m-2 DRF estimated in the IPCC 5th Assessment Report. We suggest that the DRF of BC has previously been overestimated due to the overestimation of the BC lifetime and the

  20. Exploiting simultaneous observational constraints on mass and absorption to estimate the global direct radiative forcing of black carbon and brown carbon

    NASA Astrophysics Data System (ADS)

    Wang, X.; Heald, C. L.; Ridley, D. A.; Schwarz, J. P.; Spackman, J. R.; Perring, A. E.; Coe, H.; Liu, D.; Clarke, A. D.

    2014-10-01

    Atmospheric black carbon (BC) is a leading climate warming agent, yet uncertainties on the global direct radiative forcing (DRF) remain large. Here we expand a global model simulation (GEOS-Chem) of BC to include the absorption enhancement associated with BC coating and separately treat both the aging and physical properties of fossil-fuel and biomass-burning BC. In addition we develop a global simulation of brown carbon (BrC) from both secondary (aromatic) and primary (biomass burning and biofuel) sources. The global mean lifetime of BC in this simulation (4.4 days) is substantially lower compared to the AeroCom I model means (7.3 days), and as a result, this model captures both the mass concentrations measured in near-source airborne field campaigns (ARCTAS, EUCAARI) and surface sites within 30%, and in remote regions (HIPPO) within a factor of 2. We show that the new BC optical properties together with the inclusion of BrC reduces the model bias in absorption aerosol optical depth (AAOD) at multiple wavelengths by more than 50% at AERONET sites worldwide. However our improved model still underestimates AAOD by a factor of 1.4 to 2.8 regionally, with the largest underestimates in regions influenced by fire. Using the RRTMG model integrated with GEOS-Chem we estimate that the all-sky top-of-atmosphere DRF of BC is +0.13 Wm-2 (0.08 Wm-2 from anthropogenic sources and 0.05 Wm-2 from biomass burning). If we scale our model to match AERONET AAOD observations we estimate the DRF of BC is +0.21 Wm-2, with an additional +0.11 Wm-2 of warming from BrC. Uncertainties in size, optical properties, observations, and emissions suggest an overall uncertainty in BC DRF of -80%/+140%. Our estimates are at the lower end of the 0.2-1.0 Wm-2 range from previous studies, and substantially less than the +0.6 Wm-2 DRF estimated in the IPCC 5th Assessment Report. We suggest that the DRF of BC has previously been overestimated due to the overestimation of the BC lifetime (including the

  1. Conjugated polymer and drug co-encapsulated nanoparticles for Chemo- and Photo-thermal Combination Therapy with two-photon regulated fast drug release

    NASA Astrophysics Data System (ADS)

    Yuan, Youyong; Wang, Zuyong; Cai, Pingqiang; Liu, Jie; Liao, Lun-De; Hong, Minghui; Chen, Xiaodong; Thakor, Nitish; Liu, Bin

    2015-02-01

    The spatial-temporal synchronization of photothermal therapy and chemotherapy is highly desirable for an efficient cancer treatment with synergistic effect. Herein, we developed a chemotherapeutic drug doxorubicin (DOX) and photothermal conjugated polymer (CP) co-loaded nanoplatform using a near-infrared (NIR) laser responsive amphiphilic brush copolymer as the encapsulation matrix. The obtained nanoparticles (NPs) exhibit good monodispersity and excellent stability, which can efficiently convert laser energy into thermal energy for photothermal therapy. Moreover, the hydrophobic polymer matrix bearing a number of 2-diazo-1,2-naphthoquinones (DNQ) moieties could be transformed to a hydrophilic one upon NIR two-photon laser irradiation, which leads to fast drug release. Furthermore, the surface modification of the NPs with cyclic arginine-glycine-aspartic acid (cRGD) tripeptide significantly enhances the accumulation of the NPs within integrin αvβ3 overexpressed cancer cells. The half-maximal inhibitory concentration (IC50) of the combination therapy is 13.7 μg mL-1, while the IC50 for chemotherapy and photothermal therapy alone is 147.8 μg mL-1 and 36.2 μg mL-1, respectively. The combination index (C.I.) is 0.48 (<1), which indicates the synergistic effect for chemotherapy and PTT. These findings provide an excellent NIR laser regulated nanoplatform for combined cancer treatment with synergistic effect due to the synchronous chemo- and photo-thermal therapy.

  2. Dispersive bi-stability in a vertical microcavity-based saturable absorber due to photo-thermal effect and initial phase-detuning

    NASA Astrophysics Data System (ADS)

    Pradhan, R.; Saha, S.; Datta, P. K.

    2013-01-01

    Round-trip phase-shifts with intensity of an input signal due to saturable index change and optically induced thermal effects in a vertical cavity semiconductor (quantum wells) saturable absorber (VCSSA) are investigated analytically to observe counter-clockwise bi-stability in transmission mode and clockwise bi-stability in reflection mode. Simultaneous effects of Kerr nonlinearity and cavity heating on resonance wavelength-shift of the VCSSA micro-cavity are investigated. It is found that these bi-stable characteristics are possible to the absorption edge of nonlinear material for long wavelength side operations of low intensity resonance wavelength of the micro-cavity, where dispersion of absorption and refraction are neglected over a small range of optical wavelength tuning (δλ˜10 nm). Simulations are carried out to find out optimized parameters of the device for bi-stable characteristics. Operations are demonstrated for InGaAs/InP quantum wells based VCSSA with low intensity resonance wavelength of 1570 nm. For counter-clockwise bi-stable switching at working wavelength of 1581 nm, an input intensity variation of 0.79IS is required with top (Rt) and back DBR reflectivity (Rb) of 91% and 93%, respectively, where IS represents the absorption saturation intensity of nonlinear medium. Whereas, the clockwise bi-stability occurs at 0.22IS for working wavelength of 1578 nm with Rt of 90% and Rb of 98%, respectively.

  3. Multifunctional PEG modified DOX loaded mesoporous silica nanoparticle@CuS nanohybrids as photo-thermal agent and thermal-triggered drug release vehicle for hepatocellular carcinoma treatment

    NASA Astrophysics Data System (ADS)

    Wu, Lingjie; Wu, Ming; Zeng, Yongyi; Zhang, Da; Zheng, Aixian; Liu, Xiaolong; Liu, Jingfeng

    2015-01-01

    The combination of a multi-therapeutic mode with a controlled fashion is a key improvement in nanomedicine. Here, we synthesized polyethylene glycol (PEG)-modified doxorubicin (DOX)-loaded mesoporous silica nanoparticle (MSN) @CuS nanohybrids as efficient drug delivery carriers, combined with photothermal therapy and chemotherapy to enhance the therapeutic efficacy on hepatocellular carcinoma (HCC). The physical properties of the nanohybrids were characterized by transmission electron microscopy (TEM), N2 adsorption and desorption experiments and by the Vis-NIR absorption spectra. The results showed that the doxorubicin could be stored in the inner pores of mesoporous silica nanoparticles; the CuS nanoparticles, which are coated on the surface of a mesoporous silica nanoparticle, could serve as efficient photothermal therapy (PTT) agents; the loaded drug release could be easily triggered by NIR irradiation. The combination of the PTT treatment with controlled chemotherapy could further enhance the cancer ablation ability compared to any of the single approaches alone. Hence, the reported PEG-modified DOX-loaded mesoporous silica nanoparticle@CuS nanohybrids might be very promising therapeutic agents for HCC treatment.

  4. Poverty-Exploitation-Alienation.

    ERIC Educational Resources Information Center

    Bronfenbrenner, Martin

    1980-01-01

    Illustrates how knowledge derived from the discipline of economics can be used to help shed light on social problems such as poverty, exploitation, and alienation, and can help decision makers form policy to minimize these and similar problems. (DB)

  5. Exploitability Assessment with TEASER

    DTIC Science & Technology

    2017-05-01

    dear friends Leo St. Amour, Ricky T, Andreas Kellas, and Paul Deardorff for taking time out of their busy schedules to proofread this thesis. Last, I...in glibc mal- loc function. Marked as severe on Chromium, but no known exploit Table 5.1: Summary of results of TEASER compared with other tools and

  6. Thermally induced nonlinear optical absorption in metamaterial perfect absorbers

    NASA Astrophysics Data System (ADS)

    Guddala, Sriram; Kumar, Raghwendra; Ramakrishna, S. Anantha

    2015-03-01

    A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks was fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm2.

  7. Multi-zinc oxide-cores@uni-barium sulfate-shell with improved photo-, thermal-, and ambient-stability: Non-equilibrium sorption fabrication and light-emitting diodes application.

    PubMed

    Liang, Ya-Chuan; Liu, Kai-Kai; Wu, Xue-Ying; Lu, Xian-Li; Lu, Ying-Jie; Zhao, Qi; Shan, Chong-Xin

    2018-05-29

    ZnO as an eco-friendly material shows bright luminescence under UV illumination when it is tailored into nanoscale size, which makes it a promising luminescent nanomaterial. However, the poor stability of ZnO hinders its applications drastically. In this work, multi-ZnO-cores@uni-BaSO 4 -shell (mZnO@uBaSO 4 ) nanocomposite has been prepared through a non-equilibrium sorption process employing ZnO QDs as the "seeds" and BaSO 4 as the "valve". The mZnO@uBaSO 4 nanocomposite shows improved photo-, thermal- and ambient-stability compare with bare ZnO QDs. The fluorescence efficiency of the mZnO@uBaSO 4 nanocomposite decreases little even after 60 h of UV irradiation compare with ZnO QDs. The mZnO@uBaSO 4 nanocomposite shows bright luminescence with little decrease even the ambient temperature up to 160 °C and the nanocomposite shows strong resistance to harsh environment. By coating the mZnO@uBaSO 4 nanocomposite and commercial phosphors onto UV-chip, light-emitting diode (LED) with correlated color temperature, Commission Internationale de L'Eclairage coordinate, color rendering index and luminous efficiency of 6109 K, (0.32, 0.33), 85 and 47.33 lm/W have been realized, and this will make a great step towards eco-friendly UV-pumped LEDs. Copyright © 2018. Published by Elsevier Inc.

  8. Nanostructured Basaltfiberconcrete Exploitational Characteristics

    NASA Astrophysics Data System (ADS)

    Saraykina, K. A.; Shamanov, V. A.

    2017-11-01

    The article demonstrates that the mass use of basalt fiber concrete (BFC) is constrained by insufficient study of their durability and serviceability in a variety of environments. This research is aimed at the study of the basalt fiber corrosion processes in the cement stone of BFC, the control of the new products structure formation in order to protect the reinforcing fiber from alkaline destruction and thereby improve the exploitational characteristics of the composite. The research result revealed that the modification of basaltfiber concrete by the dispersion of MWNTs contributes to the directional formation of new products in the cement matrix. The HAM additive in basaltfiberconcrete provides for the binding of portlandite to low-basic calcium hydroaluminosilicates, thus reducing the aggressive effect of the cement environment on the reinforcing fibers properties. The complex modification of BFC with nanostructured additives provides for an increase in its durability and exploitational properties (strength, frost resistance and water resistance) due to basalt fiber protection from alkali corrosion on account of the compacting of the contact zone “basalt fiber - cement stone” and designing of the new products structure and morphology of cement matrix over the fiber surface.

  9. 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

  10. Abnormal photothermal effect of laser radiation on highly defect oxide bronze nanoparticles under the sub-threshold excitation of absorption

    NASA Astrophysics Data System (ADS)

    Gulyaev, P.; Kotvanova, M.; Omelchenko, A.

    2017-05-01

    The mechanism of abnormal photo-thermal effect of laser radiation on nanoparticles of oxide bronzes has been proposed in this paper. The basic features of the observed effect are: a) sub-threshold absorption of laser radiation by the excitation of donor-like levels formed in the energy gap due to superficial defects of the oxide bronze nano-crystals; b) an interband radiationless transition of energy of excitation on deep triplet levels and c) consequent recombination occurring at the plasmon absorption. K or Na atoms thermally intercalated to the octahedral crystal structure of TiO2 in the wave SHS combustion generate acceptor levels in the gap. The prepared oxide bronzes of the non-stoichiometric composition NaxTiO2 and KxTiO2 were examined by high resolution TEM, and then grinded in a planetary mill with powerful dispersion energy density up to 4000 J/g. This made it possible to obtain nanoparticles about 50 nm with high surface defect density (1017-1019 cm-2 at a depth of 10 nm). High photo-thermal effect of laser radiation on the defect nanocrystals observed after its impregnation into cartilaginous tissue exceeds 7 times in comparison with the intact ones.

  11. 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.

  12. Percutaneous absorption

    PubMed Central

    Brisson, Paul

    1974-01-01

    Clinical effectiveness of topically applied medications depends on the ability of the active ingredient to leave its vehicle and penetrate into the epidermis. The stratum corneum is that layer of the epidermis which functionally is the most important in limiting percutaneous absorption, showing the characteristics of a composite semipermeable membrane. A mathematical expression of transepidermal diffusion may be derived from Fick's Law of mass transport; factors altering the rate of diffusion are discussed. PMID:4597976

  13. 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

  14. 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

  15. ABSORPTION ANALYZER

    DOEpatents

    Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.

    1961-11-14

    A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron absorption cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the absorption cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. (AEC)

  16. 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.

  17. Network exploitation using WAMI tracks

    NASA Astrophysics Data System (ADS)

    Rimey, Ray; Record, Jim; Keefe, Dan; Kennedy, Levi; Cramer, Chris

    2011-06-01

    Creating and exploiting network models from wide area motion imagery (WAMI) is an important task for intelligence analysis. Tracks of entities observed moving in the WAMI sensor data are extracted, then large numbers of tracks are studied over long time intervals to determine specific locations that are visited (e.g., buildings in an urban environment), what locations are related to other locations, and the function of each location. This paper describes several parts of the network detection/exploitation problem, and summarizes a solution technique for each: (a) Detecting nodes; (b) Detecting links between known nodes; (c) Node attributes to characterize a node; (d) Link attributes to characterize each link; (e) Link structure inferred from node attributes and vice versa; and (f) Decomposing a detected network into smaller networks. Experimental results are presented for each solution technique, and those are used to discuss issues for each problem part and its solution technique.

  18. Effects of γ-ray irradiation on optical absorption and laser damage performance of KDP crystals containing arsenic impurities.

    PubMed

    Guo, D C; Jiang, X D; Huang, J; Wang, F R; Liu, H J; Xiang, X; Yang, G X; Zheng, W G; Zu, X T

    2014-11-17

    The effects of γ-irradiation on potassium dihydrogen phosphate crystals containing arsenic impurities are investigated with different optical diagnostics, including UV-VIS absorption spectroscopy, photo-thermal common-path interferometer and photoluminescence spectroscopy. The optical absorption spectra indicate that a new broad absorption band near 260 nm appears after γ-irradiation. It is found that the intensity of absorption band increases with the increasing irradiation dose and arsenic impurity concentration. The simulation of radiation defects show that this absorption is assigned to the formation of AsO₄⁴⁻ centers due to arsenic ions substituting for phosphorus ions. Laser-induced damage threshold test is conducted by using 355 nm nanosecond laser pulses. The correlations between arsenic impurity concentration and laser induced damage threshold are presented. The results indicate that the damage performance of the material decreases with the increasing arsenic impurity concentration. Possible mechanisms of the irradiation-induced defects formation under γ-irradiation of KDP crystals are discussed.

  19. The ESA Geohazard Exploitation Platform

    NASA Astrophysics Data System (ADS)

    Bally, Philippe; Laur, Henri; Mathieu, Pierre-Philippe; Pinto, Salvatore

    2015-04-01

    Earthquakes represent one of the world's most significant hazards in terms both of loss of life and damages. In the first decade of the 21st century, earthquakes accounted for 60 percent of fatalities from natural disasters, according to the United Nations International Strategy for Disaster Reduction (UNISDR). To support mitigation activities designed to assess and reduce risks and improve response in emergency situations, satellite EO can be used to provide a broad range of geo-information services. This includes for instance crustal block boundary mapping to better characterize active faults, strain rate mapping to assess how rapidly faults are deforming, soil vulnerability mapping to help estimate how the soil is behaving in reaction to seismic phenomena, geo-information to assess the extent and intensity of the earthquake impact on man-made structures and formulate assumptions on the evolution of the seismic sequence, i.e. where local aftershocks or future main shocks (on nearby faults) are most likely to occur. In May 2012, the European Space Agency and the GEO Secretariat convened the International Forum on Satellite EO for Geohazards now known as the Santorini Conference. The event was the continuation of a series of international workshops such as those organized by the Geohazards Theme of the Integrated Global Observing Strategy Partnership. In Santorini the seismic community has set out a vision of the EO contribution to an operational global seismic risk program, which lead to the Geohazard Supersites and Natural Laboratories (GSNL) initiative. The initial contribution of ESA to suuport the GSNL was the first Supersites Exploitation Platform (SSEP) system in the framework of Grid Processing On Demand (GPOD), now followed by the Geohazard Exploitation Platform (GEP). In this presentation, we will describe the contribution of the GEP for exploiting satellite EO for geohazard risk assessment. It is supporting the GEO Supersites and has been further

  20. Separating higher-order nonlinearities in transient absorption microscopy

    NASA Astrophysics Data System (ADS)

    Wilson, Jesse W.; Anderson, Miguel; Park, Jong Kang; Fischer, Martin C.; Warren, Warren S.

    2015-08-01

    The transient absorption response of melanin is a promising optically-accessible biomarker for distinguishing malignant melanoma from benign pigmented lesions, as demonstrated by earlier experiments on thin sections from biopsied tissue. The technique has also been demonstrated in vivo, but the higher optical intensity required for detecting these signals from backscattered light introduces higher-order nonlinearities in the transient response of melanin. These components that are higher than linear with respect to the pump or the probe introduce intensity-dependent changes to the overall response that complicate data analysis. However, our data also suggest these nonlinearities might be advantageous to in vivo imaging, in that different types of melanins have different nonlinear responses. Therefore, methods to separate linear from nonlinear components in transient absorption measurements might provide additional information to aid in the diagnosis of melanoma. We will discuss numerical methods for analyzing the various nonlinear contributions to pump-probe signals, with the ultimate objective of real time analysis using digital signal processing techniques. To that end, we have replaced the lock-in amplifier in our pump-probe microscope with a high-speed data acquisition board, and reprogrammed the coprocessor field-programmable gate array (FPGA) to perform lock-in detection. The FPGA lock-in offers better performance than the commercial instrument, in terms of both signal to noise ratio and speed. In addition, the flexibility of the digital signal processing approach enables demodulation of more complicated waveforms, such as spread-spectrum sequences, which has the potential to accelerate microscopy methods that rely on slow relaxation phenomena, such as photo-thermal and phosphorescence lifetime imaging.

  1. The exploitation argument against commercial surrogacy.

    PubMed

    Wilkinson, Stephen

    2003-04-01

    This paper discusses the exploitation argument against commercial surrogacy: the claim that commercial surrogacy is morally objectionable because it is exploitative. The following questions are addressed. First, what exactly does the exploitation argument amount to? Second, is commercial surrogacy in fact exploitative? Third, if it were exploitative, would this provide a sufficient reason to prohibit (or otherwise legislatively discourage) it? The focus throughout is on the exploitation of paid surrogates, although it is noted that other parties (e.g. 'commissioning parents') may also be the victims of exploitation. It is argued that there are good reasons for believing that commercial surrogacy is often exploitative. However, even if we accept this, the exploitation argument for prohibiting (or otherwise legislatively discouraging) commercial surrogacy remains quite weak. One reason for this is that prohibition may well 'backfire' and lead to potential surrogates having to do other things that are more exploitative and/or more harmful than paid surrogacy. It is concluded therefore that those who oppose exploitation should (rather than attempting to stop particular practices like commercial surrogacy) concentrate on: (a) improving the conditions under which paid surrogates 'work'; and (b) changing the background conditions (in particular, the unequal distribution of power and wealth) which generate exploitative relationships.

  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. 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.

  4. 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.

  5. Exploiting Symmetry on Parallel Architectures.

    NASA Astrophysics Data System (ADS)

    Stiller, Lewis Benjamin

    1995-01-01

    This thesis describes techniques for the design of parallel programs that solve well-structured problems with inherent symmetry. Part I demonstrates the reduction of such problems to generalized matrix multiplication by a group-equivariant matrix. Fast techniques for this multiplication are described, including factorization, orbit decomposition, and Fourier transforms over finite groups. Our algorithms entail interaction between two symmetry groups: one arising at the software level from the problem's symmetry and the other arising at the hardware level from the processors' communication network. Part II illustrates the applicability of our symmetry -exploitation techniques by presenting a series of case studies of the design and implementation of parallel programs. First, a parallel program that solves chess endgames by factorization of an associated dihedral group-equivariant matrix is described. This code runs faster than previous serial programs, and discovered it a number of results. Second, parallel algorithms for Fourier transforms for finite groups are developed, and preliminary parallel implementations for group transforms of dihedral and of symmetric groups are described. Applications in learning, vision, pattern recognition, and statistics are proposed. Third, parallel implementations solving several computational science problems are described, including the direct n-body problem, convolutions arising from molecular biology, and some communication primitives such as broadcast and reduce. Some of our implementations ran orders of magnitude faster than previous techniques, and were used in the investigation of various physical phenomena.

  6. Two questions about surrogacy and exploitation.

    PubMed

    Wertheimer, Alan

    1992-01-01

    In this article I will consider two related questions about surrogacy and exploitation: (1) Is surrogacy exploitative? (2) If surrogacy is exploitative, what is the moral force of this exploitation? Briefly stated, I shall argue that whether surrogacy is exploitative depends on whether exploitation must be harmful to the exploited party or whether (as I think) there can be mutually advantageous exploitation. It also depends on some facts about surrogacy about which we have little reliable evidence and on our philosophical view on what counts as a harm to the surrogate. Our answer to the second question will turn in part on the account of exploitation we invoke in answering the first question and in part on the way in which we resolve some other questions about the justification of state interference. I shall suggest, however, that if surrogacy is a form of voluntary and mutually advantageous exploitation, then there is a strong presumption that surrogacy contracts should be permitted and even enforceable, although that presumption may be overridden on other grounds.

  7. National Center for Missing and Exploited Children

    MedlinePlus

    ... Professional Organizations & Networks National & International Collaboration EN SP Report Child Sexual Exploitation Make a CYBERTIPLINE Report Number of reports NCMEC responded to in 2017 regarding possible child ...

  8. Quantum-enhanced absorption refrigerators

    PubMed Central

    Correa, Luis A.; Palao, José P.; Alonso, Daniel; Adesso, Gerardo

    2014-01-01

    Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step towards the technological exploitation of autonomous quantum refrigerators. PMID:24492860

  9. Melting Frozen Droplets Using Photo-Thermal Traps

    NASA Astrophysics Data System (ADS)

    Dash, Susmita; de Ruiter, Jolet; Varanasi, Kripa

    2017-11-01

    Ice buildup is an operational and safety hazard in wind turbines, power lines, and airplanes. While traditional de-icing methods are energy-intensive or environmentally unfriendly, passive anti-icing approach using superhydrophobic surfaces fails under humid conditions, which necessitates development of passive deicing methods. Here, we investigate a passive technique for deicing using a multi-layer surface design that can efficiently absorb and convert the incident solar radiation to heat. The corresponding increase in substrate temperature allows for easy removal of frozen droplets from the surface. We demonstrate the deicing performance of the designed surface both at very low temperatures, and under frost and snow coverage.

  10. Photo-thermal nanosystems for diseased cell treatment

    NASA Astrophysics Data System (ADS)

    Raeesi, Vahid

    The prevalence of cancer and infectious disease demands for development of more effective treatment technologies. Current standard chemo- and radiotherapy for cancer offer only relative therapeutic efficacy at the cost of significant side-effects. On the other hand, resistance of microbes to current antibiotics has raised serious concern in public health sectors such as hospitals. Thermal therapy is an alternative technique that employs high temperatures to treat diseased cells via direct and indirect heat effects. Owing to its nature, this technique can offer enhanced therapeutic efficacy in local diseased regions via either mono- or combinatorial platforms and very minimal side-effects. However, existing bulk heating systems are limited in providing selective and controlled temperature rise in the desired region at tissue/cellular scales. This compromises the therapeutic efficacy of the treatment and increases the risk of off-target heating in healthy tissues. In this thesis, we propose the use of heat-generating nanoparticles to precisely target heat into small regions and study how they can be applied in cancer and bacteria treatment. Our model nanoparticle system generates heat by light stimulation. Different nanosystems based on this particle are developed and their thermal effects on therapeutic distribution are explored at tumor tissue and cellular scales. In addition, the thermal effect of these nanoparticles is utilized to overcome microbial resistance. By mechanistic understanding of nanoparticle thermal effects at different length scales, this research helps to rationalize proper design and development of heat- generating nanomedicine for cancer and microbial treatments.

  11. Exploitation: One View of Industry and Business.

    ERIC Educational Resources Information Center

    Swanson, Richard A.; And Others

    1986-01-01

    This article examines the meaning of exploitation with specific reference to industry and business. The authors contend that the concept of exploitation--"the unjust or improper use of another person for one's own profit or advantage"--should be studied to improve understanding of the dynamics of the workplace. (Author/CT)

  12. Transitioning from AOP to IATA - Exploiting mechanistic ...

    EPA Pesticide Factsheets

    Slide presentation at satellite meeting of the QSAR2016 Meeting on How to Transition from AOP to IATA-Exploiting mechanistic insight for practical decision making. . Slide presentation at satellite meeting of the QSAR2016 Meeting on How to Transition from AOP to IATA-Exploiting mechanistic insight for practical decision making. .

  13. 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.

  14. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    PubMed

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  15. Organ sales: exploitative at any price?

    PubMed

    Lawlor, Rob

    2014-05-01

    In many cases, claims that a transaction is exploitative will focus on the details of the transaction, such as the price paid or conditions. For example, in a claim that a worker is exploited, the grounds for the claim are usually that the pay is not sufficient or the working conditions too dangerous. In some cases, however, the claim that a transaction is exploitative is not seen to rely on these finer details. Many, for example, claim that organ sales would be exploitative, in a way that doesn't seem to depend on the details. This article considers, but ultimately rejects, a number of arguments which could be used to defend this sort of claim. © 2012 John Wiley & Sons Ltd.

  16. Solar absorption surface panel

    DOEpatents

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  17. Petawatt laser absorption bounded

    PubMed Central

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-01-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials. PMID:24938656

  18. 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

  19. Exploitation in International Paid Surrogacy Arrangements.

    PubMed

    Wilkinson, Stephen

    2016-05-01

    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.

  20. Quasar Absorption Studies

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  1. Rethinking exploitation: a process-centered account.

    PubMed

    Jansen, Lynn A; Wall, Steven

    2013-12-01

    Exploitation has become an important topic in recent discussions of biomedical and research ethics. This is due in no small measure to the influence of Alan Wertheimer's path-breaking work on the subject. This paper presents some objections to Wertheimer's account of the concept. The objections attempt to show that his account places too much emphasis on outcome-based considerations and too little on process-based considerations. Building on these objections, the paper develops an alternative process-centered account of the concept. This alternative account of exploitation takes as its point of departure the broadly Kantian notion that it is wrong to use another as an instrument for the advancement of one's own ends. It sharpens this slippery notion and adds a number of refinements to it. The paper concludes by arguing that process-centered accounts of exploitation better illuminate the ethical challenges posed by research on human subjects than outcome-centered accounts.

  2. Deception in plants: mimicry or perceptual exploitation?

    PubMed

    Schaefer, H Martin; Ruxton, Graeme D

    2009-12-01

    Mimicry involves adaptive resemblance between a mimic and a model. However, despite much recent research, it remains contentious in plants. Here, we review recent progress on studying deception by flowers, distinguishing between plants relying on mimicry to achieve pollination and those relying on the exploitation of the perceptual biases of animals. We disclose fundamental differences between both mechanisms and explain why the evolution of exploitation is less constrained than that of mimicry. Exploitation of perceptual biases might thus be a precursor for the gradual evolution of mimicry. Increasing knowledge on the sensory and cognitive filters in animals, and on the selective pressures that maintain them, should aid researchers in tracing the evolutionary dynamics of deception in plants.

  3. Realistic absorption coefficient of ultrathin films

    NASA Astrophysics Data System (ADS)

    Cesaria, M.; Caricato, A. P.; Martino, M.

    2012-10-01

    Both a theoretical algorithm and an experimental procedure are discussed of a new route to determine the absorption/scattering properties of thin films deposited on transparent substrates. Notably, the non-measurable contribution of the film-substrate interface is inherently accounted for. While the experimental procedure exploits only measurable spectra combined according to a very simple algorithm, the theoretical derivation does not require numerical handling of the acquired spectra or any assumption on the film homogeneity and substrate thickness. The film absorption response is estimated by subtracting the measured absorption spectrum of the bare substrate from that of the film on the substrate structure but in a non-straightforward way. In fact, an assumption about the absorption profile of the overall structure is introduced and a corrective factor accounting for the relative film-to-substrate thickness. The method is tested on films of a well known material (ITO) as a function of the film structural quality and influence of the film-substrate interface, both deliberately changed by thickness tuning and doping. Results are found fully consistent with information obtained by standard optical analysis and band gap values reported in the literature. Additionally, comparison with a conventional method demonstrates that our route is generally more accurate even if particularly suited for very thin films.

  4. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

    Koo, Sung I. (Inventor); Noh, Sang K. (Inventor); Hua, Duy H. (Inventor)

    2004-01-01

    A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

  5. Absorption heat pump system

    DOEpatents

    Grossman, Gershon

    1984-01-01

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  6. Absorption heat pump system

    DOEpatents

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  7. Laser Atmospheric Absorption Studies.

    DTIC Science & Technology

    1977-05-01

    A. Modification of Commercial C09 Laser 50 B. CW HF/DF Laser System * 53 C. Microcomputer Data Link 55 D . Fourier Transform...improved accuracy are used [5]. c. The absorption coefficient is listed for each absorbing species separately which some codes require. d . A super...series of water vapor absorption measurements was planned. The results of the first four lines studied are presented here in Figures 33a- d . Figure

  8. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R [Albuquerque, NM; Reed, Scott T [Albuquerque, NM; Ashley, Carol S [Albuquerque, NM; Martinez, F Edward [Horseheads, NY

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  9. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R [Albuquerque, NM; Reed, Scott T [Albuquerque, NM; Ashley, Carol S [Albuquerque, NM; Martinez, F Edward [Horseheads, NY

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  10. Bulk damage and absorption in fused silica due to high-power laser applications

    NASA Astrophysics Data System (ADS)

    Nürnberg, F.; Kühn, B.; Langner, A.; Altwein, M.; Schötz, G.; Takke, R.; Thomas, S.; Vydra, J.

    2015-11-01

    Laser fusion projects are heading for IR optics with high broadband transmission, high shock and temperature resistance, long laser durability, and best purity. For this application, fused silica is an excellent choice. The energy density threshold on IR laser optics is mainly influenced by the purity and homogeneity of the fused silica. The absorption behavior regarding the hydroxyl content was studied for various synthetic fused silica grades. The main absorption influenced by OH vibrational excitation leads to different IR attenuations for OH-rich and low-OH fused silica. Industrial laser systems aim for the maximum energy extraction possible. Heraeus Quarzglas developed an Yb-doped fused silica fiber to support this growing market. But the performance of laser welding and cutting systems is fundamentally limited by beam quality and stability of focus. Since absorption in the optical components of optical systems has a detrimental effect on the laser focus shift, the beam energy loss and the resulting heating has to be minimized both in the bulk materials and at the coated surfaces. In collaboration with a laser research institute, an optical finisher and end users, photo thermal absorption measurements on coated samples of different fused silica grades were performed to investigate the influence of basic material properties on the absorption level. High purity, synthetic fused silica is as well the material of choice for optical components designed for DUV applications (wavelength range 160 nm - 260 nm). For higher light intensities, e.g. provided by Excimer lasers, UV photons may generate defect centers that effect the optical properties during usage, resulting in an aging of the optical components (UV radiation damage). Powerful Excimer lasers require optical materials that can withstand photon energy close to the band gap and the high intensity of the short pulse length. The UV transmission loss is restricted to the DUV wavelength range below 300 nm and

  11. Absorption fluids data survey

    NASA Astrophysics Data System (ADS)

    Macriss, R. A.; Zawacki, T. S.

    Development of improved data for the thermodynamic, transport and physical properties of absorption fluids were studied. A specific objective of this phase of the study is to compile, catalog and coarse screen the available US data of known absorption fluid systems and publish it as a first edition document to be distributed to manufacturers, researchers and others active in absorption heat pump activities. The methodology and findings of the compilation, cataloguing and coarse screening of the available US data on absorption fluid properties and presents current status and future work on this project are summarized. Both in house file and literature searches were undertaken to obtain available US publications with pertinent physical, thermodynamic and transport properties data for absorption fluids. Cross checks of literature searches were also made, using available published bibliographies and literature review articles, to eliminate secondary sources for the data and include only original sources and manuscripts. The properties of these fluids relate to the liquid and/or vapor state, as encountered in normal operation of absorption equipment employing such fluids, and to the crystallization boundary of the liquid phase, where applicable. The actual data were systematically classified according to the type of fluid and property, as well as temperature, pressure and concentration ranges over which data were available. Data were sought for 14 different properties: Vapor-Liquid Equilibria, Crystallization Temperature, Corrosion Characteristics, Heat of Mixing, Liquid-Phase-Densities, Vapor-Liquid-Phase Enthalpies, Specific Heat, Stability, Viscosity, Mass Transfer Rate, Heat Transfer Rate, Thermal Conductivity, Flammability, and Toxicity.

  12. The World's Exploited Children: Growing Up Sadly.

    ERIC Educational Resources Information Center

    Knight, William James

    This monograph, fourth in a series on labor development, focuses on child exploitation in the context of child labor. The collection of papers briefly discusses (1) the relation between conditions of poverty and the prevalence of child labor in developing countries; (2) the lack of effectiveness of labor legislation in preventing child…

  13. 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…

  14. 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

  15. Dissemination and Exploitation: Project Goals beyond Science

    NASA Astrophysics Data System (ADS)

    Hamann, Kristin; Reitz, Anja

    2017-04-01

    Dissemination and Exploitation are essential parts of public funded projects. In Horizon 2020 a plan for the exploitation and dissemination of results (PEDR) is a requirement. The plan should contain a clear vision on the objectives of the project in relation to actions for dissemination and potential exploitation of the project results. The actions follow the basic idea to spread the knowledge and results gathered within the project and face the challenge of how to bring the results into potentially relevant policy circle and how they impact the market. The plan follows the purpose to assess the impact of the project and to address various target groups who are interested in the project results. Simply put, dissemination concentrates on the transfer of knowledge and exploitation on the commercialization of the project. Beyond the question of the measurability of project`s impact, strategies within science marketing can serve purposes beyond internal and external communication. Accordingly, project managers are facing the challenge to implement a dissemination and exploitation strategy that ideally supports the identification of all partners with the project and matches the current discourse of the project`s content within the society, politics and economy. A consolidated plan might unite all projects partners under a central idea and supports the identification with the project beyond the individual research questions. Which applications, strategies and methods can be used to bring forward a PEDR that accompanies a project successfully and allows a comprehensive assessment of the project afterwards? Which hurdles might project managers experience in the dissemination process and which tasks should be fulfilled by the project manager?

  16. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, Robert C.; Biermann, Wendell J.

    1989-01-01

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit.

  17. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, R.C.; Biermann, W.J.

    1989-05-09

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit. 1 fig.

  18. Training and business performance: the mediating role of absorptive capacities.

    PubMed

    Hernández-Perlines, Felipe; Moreno-García, Juan; Yáñez-Araque, Benito

    2016-01-01

    Training has been the focus of considerable conceptual and empirical attention but is considered a relevant factor for competitive edge in companies because it has a positive impact on business performance. This study is justified by the need for deeper analysis of the process involving the transfer of training into performance. This paper's originality lies in the implementation of the absorptive capacities approach as an appropriate conceptual framework for designing a model that reflects the connection between training and business performance through absorptive capacities. Based on the above conceptual framework and using the dual methodological implementation, a new method of analyzing the relationship between training and performance was obtained: efforts in training will not lead to performance without the mediation of absorptive. Training turns into performance if absorptive capacities are involved in this process. The suggested model becomes an appropriate framework for explaining the process of transformation of training into organizational performance, in which absorptive capacities play a key role. The findings obtained can go further owing to fs/QCA: of the different absorptive capacities, that of exploitation is a necessary condition to achieve better organizational performance. Therefore, training based on absorptive capacity will guide and facilitate the design of appropriate human resource strategies so that training results in improved performance. This conclusion is relevant for the development of a new facet of absorptive capacities by relating it to training and resulting in first-level implications for human resource management.

  19. 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

  20. Laser vibrometry exploitation for vehicle identification

    NASA Astrophysics Data System (ADS)

    Nolan, Adam; Lingg, Andrew; Goley, Steve; Sigmund, Kevin; Kangas, Scott

    2014-06-01

    Vibration signatures sensed from distant vehicles using laser vibrometry systems provide valuable information that may be used to help identify key vehicle features such as engine type, engine speed, and number of cylinders. Through the use of physics models of the vibration phenomenology, features are chosen to support classification algorithms. Various individual exploitation algorithms were developed using these models to classify vibration signatures into engine type (piston vs. turbine), engine configuration (Inline 4 vs. Inline 6 vs. V6 vs. V8 vs. V12) and vehicle type. The results of these algorithms will be presented for an 8 class problem. Finally, the benefits of using a factor graph representation to link these independent algorithms together will be presented which constructs a classification hierarchy for the vibration exploitation problem.

  1. Exploiting Non-Markovianity for Quantum Control.

    PubMed

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

    2015-07-22

    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.

  2. 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.

  3. Exploration and Exploitation During Sequential Search

    PubMed Central

    Dam, Gregory; Körding, Konrad

    2012-01-01

    When we learn how to throw darts we adjust how we throw based on where the darts stick. Much of skill learning is computationally similar in that we learn using feedback obtained after the completion of individual actions. We can formalize such tasks as a search problem; among the set of all possible actions, find the action that leads to the highest reward. In such cases our actions have two objectives: we want to best utilize what we already know (exploitation), but we also want to learn to be more successful in the future (exploration). Here we tested how participants learn movement trajectories where feedback is provided as a monetary reward that depends on the chosen trajectory. We mathematically derived the optimal search policy for our experiment using decision theory. The search behavior of participants is well predicted by an ideal searcher model that optimally combines exploration and exploitation. PMID:21585479

  4. 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

  5. Exploiting Glide Symmetry in Planar EBG Structures

    NASA Astrophysics Data System (ADS)

    Mouris, Boules A.; Quevedo-Teruel, Oscar; Thobaben, Ragnar

    2018-02-01

    Periodic structures such as electromagnetic band gap (EBG) structures can be used to prevent the propagation of electromagnetic waves within a certain frequency range known as the stop band. One of the main limitations of using EBG structures at low frequencies is their relatively large size. In this paper, we investigate the possibility of using glide symmetry in planar EBG structures to reduce their size. Simulated results demonstrate that exploiting glide symmetry in EBG structures can lead to size reduction.

  6. Exceptional Information: Recognizing Threats and Exploiting Opportunities

    DTIC Science & Technology

    2017-06-09

    EXCEPTIONAL INFORMATION : RECOGNIZING THREATS AND EXPLOITING OPPORTUNITIES A thesis presented to the Faculty of the U.S. Army...No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for... information . Send comments regarding this burden estimate or any other aspect of this collection of information , including suggestions for reducing this

  7. Absorption heat pump system

    DOEpatents

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  8. Absorption Heat Pump Cycles

    NASA Astrophysics Data System (ADS)

    Kunugi, Yoshifumi; Kashiwagi, Takao

    Various advanced absorption cycles are studied, developed and invented. In this paper, their cycles are classified and arranged using the three categories: effect, stage and loop, then an outline of the cycles are explained on the Duehring diagram. Their cycles include high COP cycles for refrigerations and heat pumps, high temperature lift cycles for heat transformer, absorption-compression hybrid cycles and heat pump transformer cycle. The highest COPi is attained by the seven effect cycle. In addition, the cycles for low temperature are invented and explained. Furthermore the power generation • refrigeration cycles are illustrated.

  9. Two-Phonon Absorption

    ERIC Educational Resources Information Center

    Hamilton, M. W.

    2007-01-01

    A nonlinear aspect of the acousto-optic interaction that is analogous to multi-photon absorption is discussed. An experiment is described in which the second-order acousto-optically scattered intensity is measured and found to scale with the square of the acoustic intensity. This experiment using a commercially available acousto-optic modulator is…

  10. 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

  11. 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. © 2017 American Medical Association. All Rights Reserved.

  12. Geothermal resources: exploration and exploitation. A bibliography

    SciTech Connect

    Not Available

    This comprehensive bibliography contains 5476 citations of foreign and domestic research reports, journal articles, patents, conference proceedings, and books concerned with the exploration and exploitation of geothermal resources. The coverage dates back as far as useful references could be obtained and extends through June 1976. References are arranged in broad subject categories and are made up of complete bibliographic citations. These are followed by a listing of subject descriptors used to describe the subject content of each reference. Four indexes are included: Corporate, Personal Author, Subject, and Report Number. Also included is a list of journals from which articles weremore » selected. (LBS)« less

  13. Cloud Based Earth Observation Data Exploitation Platforms

    NASA Astrophysics Data System (ADS)

    Romeo, A.; Pinto, S.; Loekken, S.; Marin, A.

    2017-12-01

    In the last few years data produced daily by several private and public Earth Observation (EO) satellites reached the order of tens of Terabytes, representing for scientists and commercial application developers both a big opportunity for their exploitation and a challenge for their management. New IT technologies, such as Big Data and cloud computing, enable the creation of web-accessible data exploitation platforms, which offer to scientists and application developers the means to access and use EO data in a quick and cost effective way. RHEA Group is particularly active in this sector, supporting the European Space Agency (ESA) in the Exploitation Platforms (EP) initiative, developing technology to build multi cloud platforms for the processing and analysis of Earth Observation data, and collaborating with larger European initiatives such as the European Plate Observing System (EPOS) and the European Open Science Cloud (EOSC). An EP is a virtual workspace, providing a user community with access to (i) large volume of data, (ii) algorithm development and integration environment, (iii) processing software and services (e.g. toolboxes, visualization routines), (iv) computing resources, (v) collaboration tools (e.g. forums, wiki, etc.). When an EP is dedicated to a specific Theme, it becomes a Thematic Exploitation Platform (TEP). Currently, ESA has seven TEPs in a pre-operational phase dedicated to geo-hazards monitoring and prevention, costal zones, forestry areas, hydrology, polar regions, urban areas and food security. On the technology development side, solutions like the multi cloud EO data processing platform provides the technology to integrate ICT resources and EO data from different vendors in a single platform. In particular it offers (i) Multi-cloud data discovery, (ii) Multi-cloud data management and access and (iii) Multi-cloud application deployment. This platform has been demonstrated with the EGI Federated Cloud, Innovation Platform Testbed Poland

  14. 69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER UNDER CONSTRUCTION. (DATE UNKNOWN). - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  15. 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.

  16. Sentinel-1 mission scientific exploitation activities

    NASA Astrophysics Data System (ADS)

    Desnos, Yves louis; Foumelis, Michael; Engdahl, Marcus

    2017-04-01

    The Sentinel-1 mission is the European Imaging Radar Observatory for the Copernicus joint initiative of the European Commission (EC) and the European Space Agency (ESA). Sentinel-1 mission is composed of a constellation of two satellites, Sentinel-1A and Sentinel-1B (launched in April 2014 and April 2016, respectively), sharing the same orbital plane and featuring a short repeat cycle of 6 days optimised for Synthetic Aperture Radar (SAR) interferometry science and applications. The full operation capacity was achieved after the completion of the Sentinel-1B in-orbit commissioning on 14 September 2016. Sentinel-1 data are freely available via the ESA's Sentinels Scientific Data Hub since October 2014. The data uptake by the science community has been unprecedented and numerous results have been published to date. The objective of the current paper is to provide a brief overview of the latest ESA activities, in the frame of the Scientific Exploitation of Operational Missions (SEOM) programme, aimed to facilitate the scientific exploitation of Sentinel-1 mission as well as discuss future opportunities for research.

  17. 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).

  18. Linear absorptive dielectrics

    NASA Astrophysics Data System (ADS)

    Tip, A.

    1998-06-01

    Starting from Maxwell's equations for a linear, nonconducting, absorptive, and dispersive medium, characterized by the constitutive equations D(x,t)=ɛ1(x)E(x,t)+∫t-∞dsχ(x,t-s)E(x,s) and H(x,t)=B(x,t), a unitary time evolution and canonical formalism is obtained. Given the complex, coordinate, and frequency-dependent, electric permeability ɛ(x,ω), no further assumptions are made. The procedure leads to a proper definition of band gaps in the periodic case and a new continuity equation for energy flow. An S-matrix formalism for scattering from lossy objects is presented in full detail. A quantized version of the formalism is derived and applied to the generation of Čerenkov and transition radiation as well as atomic decay. The last case suggests a useful generalization of the density of states to the absorptive situation.

  19. Vehicular impact absorption system

    NASA Technical Reports Server (NTRS)

    Knoell, A. C.; Wilson, A. H. (Inventor)

    1978-01-01

    An improved vehicular impact absorption system characterized by a plurality of aligned crash cushions of substantially cubic configuration is described. Each consists of a plurality of voided aluminum beverage cans arranged in substantial parallelism within a plurality of superimposed tiers and a covering envelope formed of metal hardware cloth. A plurality of cables is extended through the cushions in substantial parallelism with an axis of alignment for the cushions adapted to be anchored at each of the opposite end thereof.

  20. Corrosion Problems in Absorption Chillers

    ERIC Educational Resources Information Center

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  1. Exploiting solitons in all-optical networks

    NASA Astrophysics Data System (ADS)

    Atieh, Ahmad K.

    Two key components, the pulse generator and optical signal demultiplexer, needed for the implementation of all-optical soliton-based local area and wide area networks are investigated. The technology of generating a bright soliton pulse train from a sinusoidal pulse train produced as the beat signal of two distributed feedback laser diodes passed through a so-called comblike fiber structure is developed. A design methodology for this structure is discussed, and using this approach a soliton pulse source is constructed generating 1553 nm pulses at a repetition rate of 50 GHz, with pulses of full width at half maximum of 2.0 ps. The fiber structure used to generate the bright soliton pulse train employs the lowest average power for the beat signal ever reported in the literature, and the shortest length of fiber. The same structure (with a different design) is also used to produce a 47.6 GHz dark soliton pulse train with a full width at half maximum of 3.8 ps. This is the first reported use of this structure to generate dark solitons. It is shown that the comblike dispersion profile fiber structures may also be exploited for soliton pulse compression producing widths as short as 200 fs. Two approaches to implementation of optical signal demultiplexing are discussed. These are the nonlinear optical loop mirror (NOLM) and the separation of multilevel time division multiplexed signal pulses in the frequency domain by exploiting the relationship between the pulse's energy (i.e. pulse amplitude and width) and the Raman self-frequency shift. A modification of the NOLM scheme is investigated where feedback that adjusts the power of the control signal (by controlling the gain of an erbium-doped fiber amplifier introduced into the control signal input path) is employed to make the structure insensitive to the state of polarization of the signal and control pulses. In order to better understand the physical phenomena exploited in optical fiber soliton transmission and the

  2. Virtual Exploitation Environment Demonstration for Atmospheric Missions

    NASA Astrophysics Data System (ADS)

    Natali, Stefano; Mantovani, Simone; Hirtl, Marcus; Santillan, Daniel; Triebnig, Gerhard; Fehr, Thorsten; Lopes, Cristiano

    2017-04-01

    The scientific and industrial communities are being confronted with a strong increase of Earth Observation (EO) satellite missions and related data. This is in particular the case for the Atmospheric Sciences communities, with the upcoming Copernicus Sentinel-5 Precursor, Sentinel-4, -5 and -3, and ESA's Earth Explorers scientific satellites ADM-Aeolus and EarthCARE. The challenge is not only to manage the large volume of data generated by each mission / sensor, but to process and analyze the data streams. Creating synergies among the different datasets will be key to exploit the full potential of the available information. As a preparation activity supporting scientific data exploitation for Earth Explorer and Sentinel atmospheric missions, ESA funded the "Technology and Atmospheric Mission Platform" (TAMP) [1] [2] project; a scientific and technological forum (STF) has been set-up involving relevant European entities from different scientific and operational fields to define the platforḿs requirements. Data access, visualization, processing and download services have been developed to satisfy useŕs needs; use cases defined with the STF, such as study of the SO2 emissions for the Holuhraun eruption (2014) by means of two numerical models, two satellite platforms and ground measurements, global Aerosol analyses from long time series of satellite data, and local Aerosol analysis using satellite and LIDAR, have been implemented to ensure acceptance of TAMP by the atmospheric sciences community. The platform pursues the "virtual workspace" concept: all resources (data, processing, visualization, collaboration tools) are provided as "remote services", accessible through a standard web browser, to avoid the download of big data volumes and for allowing utilization of provided infrastructure for computation, analysis and sharing of results. Data access and processing are achieved through standardized protocols (WCS, WPS). As evolution toward a pre

  3. Redesigning the exploitation of wheat genetic resources.

    PubMed

    Longin, C Friedrich H; Reif, Jochen C

    2014-10-01

    More than half a million wheat genetic resources are resting in gene banks worldwide. Unlocking their hidden favorable genetic diversity for breeding is pivotal for enhancing grain yield potential, and averting future food shortages. Here, we propose exploiting recent advances in hybrid wheat technology to uncover the masked breeding values of wheat genetic resources. The gathered phenotypic information will enable a targeted choice of accessions with high value for pre-breeding among this plethora of genetic resources. We intend to provoke a paradigm shift in pre-breeding strategies for grain yield, moving away from allele mining toward genome-wide selection to bridge the yield gap between genetic resources and elite breeding pools. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Geometric saliency to characterize radar exploitation performance

    NASA Astrophysics Data System (ADS)

    Nolan, Adam; Keserich, Brad; Lingg, Andrew; Goley, Steve

    2014-06-01

    Based on the fundamental scattering mechanisms of facetized computer-aided design (CAD) models, we are able to define expected contributions (EC) to the radar signature. The net result of this analysis is the prediction of the salient aspects and contributing vehicle morphology based on the aspect. Although this approach does not provide the fidelity of an asymptotic electromagnetic (EM) simulation, it does provide very fast estimates of the unique scattering that can be consumed by a signature exploitation algorithm. The speed of this approach is particularly relevant when considering the high dimensionality of target configuration variability due to articulating parts which are computationally burdensome to predict. The key scattering phenomena considered in this work are the specular response from a single bounce interaction with surfaces and dihedral response formed between the ground plane and vehicle. Results of this analysis are demonstrated for a set of civilian target models.

  5. Exploiting CRISPR/Cas systems for biotechnology.

    PubMed

    Sampson, Timothy R; Weiss, David S

    2014-01-01

    The Cas9 endonuclease is the central component of the Type II CRISPR/Cas system, a prokaryotic adaptive restriction system against invading nucleic acids, such as those originating from bacteriophages and plasmids. Recently, this RNA-directed DNA endonuclease has been harnessed to target DNA sequences of interest. Here, we review the development of Cas9 as an important tool to not only edit the genomes of a number of different prokaryotic and eukaryotic species, but also as an efficient system for site-specific transcriptional repression or activation. Additionally, a specific Cas9 protein has been observed to target an RNA substrate, suggesting that Cas9 may have the ability to be programmed to target RNA as well. Cas proteins from other CRISPR/Cas subtypes may also be exploited in this regard. Thus, CRISPR/Cas systems represent an effective and versatile biotechnological tool, which will have significant impact on future advancements in genome engineering. © 2014 WILEY Periodicals, Inc.

  6. Exploiting CRISPR/Cas systems for biotechnology

    PubMed Central

    Sampson, Timothy R.; Weiss, David S.

    2015-01-01

    The Cas9 endonuclease is the central component of the Type II CRISPR/Cas system, a prokaryotic adaptive restriction system against invading nucleic acids, such as those originating from bacteriophages and plasmids. Recently, this RNA-directed DNA endonuclease has been harnessed to target DNA sequences of interest. Here, we review the development of Cas9 as an important tool to not only edit the genomes of a number of different prokaryotic and eukaryotic species, but also as an efficient system for site-specific transcriptional repression or activation. Additionally, a specific Cas9 protein has been observed to target an RNA substrate, suggesting that Cas9 may have the ability to be programmed to target RNA as well. Cas proteins from other CRISPR/Cas subtypes may also be exploited in this regard. Thus, CRISPR/Cas systems represent an effective and versatile biotechnological tool, which will have significant impact on future advancements in genome engineering. PMID:24323919

  7. 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.

  8. 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.

  9. Protocol to Exploit Waiting Resources for UASNs.

    PubMed

    Hung, Li-Ling; Luo, Yung-Jeng

    2016-03-08

    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.

  10. Graphene-based absorber exploiting guided mode resonances in one-dimensional gratings.

    PubMed

    Grande, M; Vincenti, M A; Stomeo, T; Bianco, G V; de Ceglia, D; Aközbek, N; Petruzzelli, V; Bruno, G; De Vittorio, M; Scalora, M; D'Orazio, A

    2014-12-15

    A one-dimensional dielectric grating, based on a simple geometry, is proposed and investigated to enhance light absorption in a monolayer graphene exploiting guided mode resonances. Numerical findings reveal that the optimized configuration is able to absorb up to 60% of the impinging light at normal incidence for both TE and TM polarizations resulting in a theoretical enhancement factor of about 26 with respect to the monolayer graphene absorption (≈2.3%). Experimental results confirm this behavior showing CVD graphene absorbance peaks up to about 40% over narrow bands of a few nanometers. The simple and flexible design points to a way to realize innovative, scalable and easy-to-fabricate graphene-based optical absorbers.

  11. Rapidly variable relatvistic absorption

    NASA Astrophysics Data System (ADS)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

    2017-10-01

    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  12. Ultraviolet absorption hygrometer

    DOEpatents

    Gersh, M.E.; Bien, F.; Bernstein, L.S.

    1986-12-09

    An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined. 5 figs.

  13. 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

  14. Proba-V Mission Exploitation Platform

    NASA Astrophysics Data System (ADS)

    Goor, E.

    2017-12-01

    VITO and partners developed the Proba-V Mission Exploitation Platform (MEP) as an end-to-end solution to drastically improve the exploitation of the Proba-V (an EC Copernicus contributing mission) EO-data archive, the past mission SPOT-VEGETATION and derived vegetation parameters by researchers, service providers (e.g. the EC Copernicus Global Land Service) and end-users. The analysis of time series of data (PB range) is addressed, as well as the large scale on-demand processing of near real-time data on a powerful and scalable processing environment. New features are still developed, but the platform is yet fully operational since November 2016 and offers A time series viewer (browser web client and API), showing the evolution of Proba-V bands and derived vegetation parameters for any country, region, pixel or polygon defined by the user. Full-resolution viewing services for the complete data archive. On-demand processing chains on a powerfull Hadoop/Spark backend. Virtual Machines can be requested by users with access to the complete data archive mentioned above and pre-configured tools to work with this data, e.g. various toolboxes and support for R and Python. This allows users to immediately work with the data without having to install tools or download data, but as well to design, debug and test applications on the platform. Jupyter Notebooks is available with some examples python and R projects worked out to show the potential of the data. Today the platform is already used by several international third party projects to perform R&D activities on the data, and to develop/host data analysis toolboxes. From the Proba-V MEP, access to other data sources such as Sentinel-2 and landsat data is also addressed. Selected components of the MEP are also deployed on public cloud infrastructures in various R&D projects. 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

  15. Exploiting fungal cell wall components in vaccines.

    PubMed

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

    2015-03-01

    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.

  16. 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

  17. 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.

  18. Exploiting Genome Structure in Association Analysis

    PubMed Central

    Kim, Seyoung

    2014-01-01

    Abstract A genome-wide association study involves examining a large number of single-nucleotide polymorphisms (SNPs) to identify SNPs that are significantly associated with the given phenotype, while trying to reduce the false positive rate. Although haplotype-based association methods have been proposed to accommodate correlation information across nearby SNPs that are in linkage disequilibrium, none of these methods directly incorporated the structural information such as recombination events along chromosome. In this paper, we propose a new approach called stochastic block lasso for association mapping that exploits prior knowledge on linkage disequilibrium structure in the genome such as recombination rates and distances between adjacent SNPs in order to increase the power of detecting true associations while reducing false positives. Following a typical linear regression framework with the genotypes as inputs and the phenotype as output, our proposed method employs a sparsity-enforcing Laplacian prior for the regression coefficients, augmented by a first-order Markov process along the sequence of SNPs that incorporates the prior information on the linkage disequilibrium structure. The Markov-chain prior models the structural dependencies between a pair of adjacent SNPs, and allows us to look for association SNPs in a coupled manner, combining strength from multiple nearby SNPs. Our results on HapMap-simulated datasets and mouse datasets show that there is a significant advantage in incorporating the prior knowledge on linkage disequilibrium structure for marker identification under whole-genome association. PMID:21548809

  19. Examining the potential exploitation of UNOS policies.

    PubMed

    Zink, Sheldon; Wertlieb, Stacey; Catalano, John; Marwin, Victor

    2005-01-01

    The United Network for Organ Sharing (UNOS) waiting list was designed as a just and equitable system through which the limited number of organs is allocated to the millions of Americans in need of a transplant. People have trusted the system because of the belief that everyone on the list has an equal opportunity to receive an organ and also that allocation is blind to matters of financial standing, celebrity or political power. Recent events have revealed that certain practices and policies have the potential to be exploited. The policies addressed in this paper enable those on the list with the proper resources to gain an advantage over other less fortunate members, creating a system that benefits not the individual most in medical need, but the one with the best resources. These policies are not only unethical but threaten the balance and success of the entire UNOS system. This paper proposes one possible solution, which seeks to balance the concepts of justice and utility.

  20. 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

  1. Exploiting range imagery: techniques and applications

    NASA Astrophysics Data System (ADS)

    Armbruster, Walter

    2009-07-01

    Practically no applications exist for which automatic processing of 2D intensity imagery can equal human visual perception. This is not the case for range imagery. The paper gives examples of 3D laser radar applications, for which automatic data processing can exceed human visual cognition capabilities and describes basic processing techniques for attaining these results. The examples are drawn from the fields of helicopter obstacle avoidance, object detection in surveillance applications, object recognition at high range, multi-object-tracking, and object re-identification in range image sequences. Processing times and recognition performances are summarized. The techniques used exploit the bijective continuity of the imaging process as well as its independence of object reflectivity, emissivity and illumination. This allows precise formulations of the probability distributions involved in figure-ground segmentation, feature-based object classification and model based object recognition. The probabilistic approach guarantees optimal solutions for single images and enables Bayesian learning in range image sequences. Finally, due to recent results in 3D-surface completion, no prior model libraries are required for recognizing and re-identifying objects of quite general object categories, opening the way to unsupervised learning and fully autonomous cognitive systems.

  2. Common IED exploitation target set ontology

    NASA Astrophysics Data System (ADS)

    Russomanno, David J.; Qualls, Joseph; Wowczuk, Zenovy; Franken, Paul; Robinson, William

    2010-04-01

    The Common IED Exploitation Target Set (CIEDETS) ontology provides a comprehensive semantic data model for capturing knowledge about sensors, platforms, missions, environments, and other aspects of systems under test. The ontology also includes representative IEDs; modeled as explosives, camouflage, concealment objects, and other background objects, which comprise an overall threat scene. The ontology is represented using the Web Ontology Language and the SPARQL Protocol and RDF Query Language, which ensures portability of the acquired knowledge base across applications. The resulting knowledge base is a component of the CIEDETS application, which is intended to support the end user sensor test and evaluation community. CIEDETS associates a system under test to a subset of cataloged threats based on the probability that the system will detect the threat. The associations between systems under test, threats, and the detection probabilities are established based on a hybrid reasoning strategy, which applies a combination of heuristics and simplified modeling techniques. Besides supporting the CIEDETS application, which is focused on efficient and consistent system testing, the ontology can be leveraged in a myriad of other applications, including serving as a knowledge source for mission planning tools.

  3. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. 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

  5. MULTIMAGNON ABSORPTION IN MNF2-OPTICAL ABSORPTION SPECTRUM.

    DTIC Science & Technology

    The absorption spectrum of MnF2 at 4.2K in the 3900A region was measured in zero external fields and in high fields. Exciton lines with magnon ...sidebands are observed, accompanied by a large number of weak satellite lines. Results on the exciton and magnon absorptions are similar to those of...McClure et al. The satellite lines are interpreted as being multi- magnon absorptions, and it is possible to fit the energy of all the absorptions with

  6. Differential optoacoustic absorption detector

    NASA Technical Reports Server (NTRS)

    Shumate, M. S. (Inventor)

    1978-01-01

    A differential optoacoustic absorption detector employed two tapered cells in tandem or in parallel. When operated in tandem, two mirrors were used at one end remote from the source of the beam of light directed into one cell back through the other, and a lens to focus the light beam into the one cell at a principal focus half way between the reflecting mirror. Each cell was tapered to conform to the shape of the beam so that the volume of one was the same as for the other, and the volume of each received maximum illumination. The axes of the cells were placed as close to each other as possible in order to connect a differential pressure detector to the cells with connecting passages of minimum length. An alternative arrangement employed a beam splitter and two lenses to operate the cells in parallel.

  7. Triple effect absorption cycles

    SciTech Connect

    Erickson, D.C.; Potnis, S.V.; Tang, J.

    1996-12-31

    Triple effect absorption chillers can achieve 50% COP improvement over double-effect systems. However, to translate this potential into cost-effective hardware, the most promising embodiments must be identified. In this study, 12 generic triple effect cycles and 76 possible hermetic loop arrangements of those 12 generic cycles were identified. The generic triple effect cycles were screened based on their pressure and solubility field requirements, generic COPs, risk involved in the component design, and number of components in a high corrosive environment. This screening identified four promising arrangements: Alkitrate Topping cycle, Pressure Staged Envelope cycle, High Pressure Overlap cycle, and Dual Loopmore » cycle. All of these arrangements have a very high COP ({approximately} 1.8), however the development risk and cost involved is different for each arrangement. Therefore, the selection of a particular arrangement will depend upon the specific situation under consideration.« less

  8. Analyzing Water's Optical Absorption

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A cooperative agreement between World Precision Instruments (WPI), Inc., and Stennis Space Center has led the UltraPath(TM) device, which provides a more efficient method for analyzing the optical absorption of water samples at sea. UltraPath is a unique, high-performance absorbance spectrophotometer with user-selectable light path lengths. It is an ideal tool for any study requiring precise and highly sensitive spectroscopic determination of analytes, either in the laboratory or the field. As a low-cost, rugged, and portable system capable of high- sensitivity measurements in widely divergent waters, UltraPath will help scientists examine the role that coastal ocean environments play in the global carbon cycle. UltraPath(TM) is a trademark of World Precision Instruments, Inc. LWCC(TM) is a trademark of World Precision Instruments, Inc.

  9. Nonequilibrium quantum absorption refrigerator

    NASA Astrophysics Data System (ADS)

    Du, Jian-Ying; Zhang, Fu-Lin

    2018-06-01

    We study a quantum absorption refrigerator, in which a target qubit is cooled by two machine qubits in a nonequilibrium steady-state. It is realized by a strong internal coupling in the two-qubit fridge and a vanishing tripartite interaction among the whole system. The coherence of a machine virtual qubit is investigated as quantumness of the fridge. A necessary condition for cooling shows that the quantum coherence is beneficial to the nonequilibrium fridge, while it is detrimental as far as the maximum coefficient of performance (COP) and the COP at maximum power are concerned. Here, the COP is defined only in terms of heat currents caused by the tripartite interaction, with the one maintaining the two-qubit nonequilibrium state being excluded. The later can be considered to have no direct involvement in extracting heat from the target, as it is not affected by the tripartite interaction.

  10. Microwave absorption properties of carbon nanocoils coated with highly controlled magnetic materials by atomic layer deposition.

    PubMed

    Wang, Guizhen; Gao, Zhe; Tang, Shiwei; Chen, Chaoqiu; Duan, Feifei; Zhao, Shichao; Lin, Shiwei; Feng, Yuhong; Zhou, Lei; Qin, Yong

    2012-12-21

    In this work, atomic layer deposition is applied to coat carbon nanocoils with magnetic Fe(3)O(4) or Ni. The coatings have a uniform and highly controlled thickness. The coated nanocoils with coaxial multilayer nanostructures exhibit remarkably improved microwave absorption properties compared to the pristine carbon nanocoils. The enhanced absorption ability arises from the efficient complementarity between complex permittivity and permeability, chiral morphology, and multilayer structure of the products. This method can be extended to exploit other composite materials benefiting from its convenient control of the impedance matching and combination of dielectric-magnetic multiple loss mechanisms for microwave absorption applications.

  11. Searching for Variability of NV Intrinsic Narrow Absorption Line Systems

    NASA Astrophysics Data System (ADS)

    Rodruck, Michael; Charlton, Jane; Ganguly, Rajib

    2018-01-01

    The majority of quasar absorption line systems with NV detected are found within the associated region (within 5000 km/s of the quasar redshift) and many/most are believed to be related to the quasar accretion disk wind or outflows. The most definite evidence that these NV absorbers are "intrinsic" is partial covering of the quasar continuum source and/or broad line region. Over 75 quasars containing NV narrow absorption lines have observations obtained at different times with the Keck/HIRES and the VLT/UVES spectrographs at high resolution. The interval between these observations range from months to a decade in the quasar rest frame. While variability is common for intrinsic broad and mini-broad absorption lines, intrinsic narrow absorption lines have been found to be less likely to vary, though systematic studies with large, high quality datasets have been limited. The variability timescales are useful for deriving gas densities and thus the distances from the central engines. This is important in mapping the quasar surroundings, understanding the accretion disk wind mechanism, and assessing the effect the wind has on the galaxy surroundings. We report on the results of a systematic study of variability of NV NALs, exploiting the overlap of targets for observations in the archives of Keck and VLT, and discuss the consequences for interpretation of the origin of intrinsic narrow absorption lines.

  12. 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.

  13. Main principles of developing exploitation models of semiconductor devices

    NASA Astrophysics Data System (ADS)

    Gradoboev, A. V.; Simonova, A. V.

    2018-05-01

    The paper represents primary tasks, solutions of which allow to develop the exploitation modes of semiconductor devices taking into account complex and combined influence of ionizing irradiation and operation factors. The structure of the exploitation model of the semiconductor device is presented, which is based on radiation and reliability models. Furthermore, it was shown that the exploitation model should take into account complex and combine influence of various ionizing irradiation types and operation factors. The algorithm of developing the exploitation model of the semiconductor devices is proposed. The possibility of creating the radiation model of Schottky barrier diode, Schottky field-effect transistor and Gunn diode is shown based on the available experimental data. The basic exploitation model of IR-LEDs based upon double AlGaAs heterostructures is represented. The practical application of the exploitation models will allow to output the electronic products with guaranteed operational properties.

  14. Social Networks, Social Media and Absorptive Capacity in Regional Small and Medium Enterprises (SMES) in Australia

    ERIC Educational Resources Information Center

    Bosua, Rachelle; Evans, Nina; Sawyer, Janet

    2013-01-01

    Small and Medium Enterprises (SMEs) are major sources of prosperity and employment and are viewed as critical to regional development in Australia. A key factor to foster productivity and growth in SMEs is their ability to identify, acquire, transform and exploit external knowledge. This ability, referred to as the "absorptive capacity…

  15. A numerical differentiation library exploiting parallel architectures

    NASA Astrophysics Data System (ADS)

    Voglis, C.; Hadjidoukas, P. E.; Lagaris, I. E.; Papageorgiou, D. G.

    2009-08-01

    We present a software library for numerically estimating first and second order partial derivatives of a function by finite differencing. Various truncation schemes are offered resulting in corresponding formulas that are accurate to order O(h), O(h), and O(h), h being the differencing step. The derivatives are calculated via forward, backward and central differences. Care has been taken that only feasible points are used in the case where bound constraints are imposed on the variables. The Hessian may be approximated either from function or from gradient values. There are three versions of the software: a sequential version, an OpenMP version for shared memory architectures and an MPI version for distributed systems (clusters). The parallel versions exploit the multiprocessing capability offered by computer clusters, as well as modern multi-core systems and due to the independent character of the derivative computation, the speedup scales almost linearly with the number of available processors/cores. Program summaryProgram title: NDL (Numerical Differentiation Library) Catalogue identifier: AEDG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 73 030 No. of bytes in distributed program, including test data, etc.: 630 876 Distribution format: tar.gz Programming language: ANSI FORTRAN-77, ANSI C, MPI, OPENMP Computer: Distributed systems (clusters), shared memory systems Operating system: Linux, Solaris Has the code been vectorised or parallelized?: Yes RAM: The library uses O(N) internal storage, N being the dimension of the problem Classification: 4.9, 4.14, 6.5 Nature of problem: The numerical estimation of derivatives at several accuracy levels is a common requirement in many computational tasks, such

  16. Proba-V Mission Exploitation Platform

    NASA Astrophysics Data System (ADS)

    Goor, Erwin; Dries, Jeroen

    2017-04-01

    VITO and partners developed the Proba-V Mission Exploitation Platform (MEP) as an end-to-end solution to drastically improve the exploitation of the Proba-V (a Copernicus contributing mission) 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 on a powerful and scalable processing environment. Furthermore data from the Copernicus Global Land Service is in scope of the platform. From November 2015 an operational Proba-V MEP environment, as an ESA operation service, is gradually deployed at the VITO data center with direct access to the complete data archive. Since autumn 2016 the platform is operational and yet several applications are released to the users, e.g. - A time series viewer, showing the evolution of Proba-V bands and derived vegetation parameters from the Copernicus Global Land Service for any area of interest. - Full-resolution viewing services for the complete data archive. - On-demand processing chains on a powerfull Hadoop/Spark backend e.g. for the calculation of N-daily composites. - Virtual Machines can be provided with access to the data archive and tools to work with this data, e.g. various toolboxes (GDAL, QGIS, GrassGIS, SNAP toolbox, …) and support for R and Python. This allows users to immediately work with the data without having to install tools or download data, but as well to design, debug and test applications on the platform. - A prototype of jupyter Notebooks is available with some examples worked out to show the potential of the data. Today the platform is used by several third party projects to perform R&D activities on the data, and to develop/host data analysis toolboxes. In parallel the platform is further improved and extended. From the MEP PROBA-V, access to Sentinel-2 and landsat data will

  17. 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

  18. 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 (c) 2017 APA, all rights reserved).

  19. Postural Hand Synergies during Environmental Constraint Exploitation

    PubMed Central

    Della Santina, Cosimo; Bianchi, Matteo; Averta, Giuseppe; Ciotti, Simone; Arapi, Visar; Fani, Simone; Battaglia, Edoardo; Catalano, Manuel Giuseppe; Santello, Marco; Bicchi, Antonio

    2017-01-01

    Humans are able to intuitively exploit the shape of an object and environmental constraints to achieve stable grasps and perform dexterous manipulations. In doing that, a vast range of kinematic strategies can be observed. However, in this work we formulate the hypothesis that such ability can be described in terms of a synergistic behavior in the generation of hand postures, i.e., using a reduced set of commonly used kinematic patterns. This is in analogy with previous studies showing the presence of such behavior in different tasks, such as grasping. We investigated this hypothesis in experiments performed by six subjects, who were asked to grasp objects from a flat surface. We quantitatively characterized hand posture behavior from a kinematic perspective, i.e., the hand joint angles, in both pre-shaping and during the interaction with the environment. To determine the role of tactile feedback, we repeated the same experiments but with subjects wearing a rigid shell on the fingertips to reduce cutaneous afferent inputs. Results show the persistence of at least two postural synergies in all the considered experimental conditions and phases. Tactile impairment does not alter significantly the first two synergies, and contact with the environment generates a change only for higher order Principal Components. A good match also arises between the first synergy found in our analysis and the first synergy of grasping as quantified by previous work. The present study is motivated by the interest of learning from the human example, extracting lessons that can be applied in robot design and control. Thus, we conclude with a discussion on implications for robotics of our findings. PMID:28900393

  20. BASIC STUDIES IN PERCUTANEOUS ABSORPTION.

    DTIC Science & Technology

    FATTY ACIDS, *SKIN(ANATOMY), ABSORPTION, ALKYL RADICALS, AMIDES, DIFFUSION, ELECTRON MICROSCOPY, HUMIDITY, LABORATORY ANIMALS, LIPIDS, ORGANIC SOLVENTS, PENETRATION, PRIVATION, PROTEINS, RATS, TEMPERATURE, WATER

  1. Optical Absorption in Liquid Semiconductors

    NASA Astrophysics Data System (ADS)

    Bell, Florian Gene

    An infrared absorption cell has been developed which is suitable for high temperature liquids which have absorptions in the range .1-10('3) cm('-1). The cell is constructed by clamping a gasket between two flat optical windows. This unique design allows the use of any optical windows chemically compatible with the liquid. The long -wavelength limit of the measurements is therefore limited only by the choice of the optical windows. The thickness of the cell can easily be set during assembly, and can be varied from 50 (mu)m to .5 cm. Measurements of the optical absorption edge were performed on the liquid alloy Se(,1-x)Tl(,x) for x = 0, .001, .002, .003, .005, .007, and .009, from the melting point up to 475(DEGREES)C. The absorption was found to be exponential in the photon energy over the experimental range from 0.3 eV to 1.2 eV. The absorption increased linearly with concentration according to the empirical relation (alpha)(,T)(h(nu)) = (alpha)(,1) + (alpha)(,2)x, and the absorption (alpha)(,1) was interpreted as the absorption in the absence of T1. (alpha)(,1) also agreed with the measured absorption in 100% Se at corresponding temperatures and energies. The excess absorption defined by (DELTA)(alpha) = (alpha)(,T)(h(nu))-(alpha)(,1) was interpreted as the absorption associated with Tl and was found to be thermally activated with an activation energy E(,t) = 0.5 eV. The exponential edge is explained as absorption on atoms immersed in strong electric fields surrounding ions. The strong fields give rise to an absorption tail similar to the Franz-Keldysh effect. A simple calculation is performed which is based on the Dow-Redfield theory of absorption in an electric field with excitonic effects included. The excess absorption at low photon energies is proportional to the square of the concentration of ions, which are proposed to exist in the liquid according to the relation C(,i) (PROPORTIONAL) x(' 1/2)(.)e('-E)t('/kT), which is the origin of the thermal activation

  2. Exploitation of prisoners in clinical research: perceptions of study participants

    PubMed Central

    Christopher, Paul P.; Stein, Michael D.; Johnson, Jennifer E.; Rich, Josiah D.; Friedmann, Peter D.; Clarke, Jennifer G.; Lidz, Charles W.

    2015-01-01

    This paper discusses findings of a study examining whether prisoners view their participation in clinical research studies as exploitative. Perspectives of seventy prisoners who were enrolled in one of six different clinical studies were analyzed. A minority of participants agreed with statements suggestive of potential exploitation. All but one participant believed that prisoners should have greater access to research. On balance, these data provide reassurance that prisoners in this sample do not view their involvement in clinical research as inappropriately exploitative. PMID:26964404

  3. Terahertz sensing of highly absorptive water-methanol mixtures with multiple resonances in metamaterials.

    PubMed

    Chen, Min; Singh, Leena; Xu, Ningning; Singh, Ranjan; Zhang, Weili; Xie, Lijuan

    2017-06-26

    Terahertz sensing of highly absorptive aqueous solutions remains challenging due to strong absorption of water in the terahertz regime. Here, we experimentally demonstrate a cost-effective metamaterial-based sensor integrated with terahertz time-domain spectroscopy for highly absorptive water-methanol mixture sensing. This metamaterial has simple asymmetric wire structures that support multiple resonances including a fundamental Fano resonance and higher order dipolar resonance in the terahertz regime. Both the resonance modes have strong intensity in the transmission spectra which we exploit for detection of the highly absorptive water-methanol mixtures. The experimentally characterized sensitivities of the Fano and dipole resonances for the water-methanol mixtures are found to be 160 and 305 GHz/RIU, respectively. This method provides a robust route for metamaterial-assisted terahertz sensing of highly absorptive chemical and biochemical materials with multiple resonances and high accuracy.

  4. Perfect absorption in nanotextured thin films via Anderson-localized photon modes

    NASA Astrophysics Data System (ADS)

    Aeschlimann, Martin; Brixner, Tobias; Differt, Dominik; Heinzmann, Ulrich; Hensen, Matthias; Kramer, Christian; Lükermann, Florian; Melchior, Pascal; Pfeiffer, Walter; Piecuch, Martin; Schneider, Christian; Stiebig, Helmut; Strüber, Christian; Thielen, Philip

    2015-10-01

    The enhancement of light absorption in absorber layers is crucial in a number of applications, including photovoltaics and thermoelectrics. The efficient use of natural resources and physical constraints such as limited charge extraction in photovoltaic devices require thin but efficient absorbers. Among the many different strategies used, light diffraction and light localization at randomly nanotextured interfaces have been proposed to improve absorption. Although already exploited in commercial devices, the enhancement mechanism for devices with nanotextured interfaces is still subject to debate. Using coherent two-dimensional nanoscopy and coherent light scattering, we demonstrate the existence of localized photonic states in nanotextured amorphous silicon layers as used in commercial thin-film solar cells. Resonant absorption in these states accounts for the enhanced absorption in the long-wavelength cutoff region. Our observations establish that Anderson localization—that is, strong localization—is a highly efficient resonant absorption enhancement mechanism offering interesting opportunities for the design of efficient future absorber layers.

  5. 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

  6. 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),more » 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

  7. Differential-optoacoustic absorption detector

    NASA Technical Reports Server (NTRS)

    Shumate, M. S.

    1977-01-01

    Two-cell spectrophone detects trace amounts of atmospheric pollutants by measuring absorption coefficients of gases with various laser sources. Device measures pressure difference between two tapered cells with differential manometer. Background signal is reduced by balanced window heating and balanced carrier gas absorption in two cells.

  8. Atmospheric absorption of sound - Update

    NASA Technical Reports Server (NTRS)

    Bass, H. E.; Sutherland, L. C.; Zuckerwar, A. J.

    1990-01-01

    Best current expressions for the vibrational relaxation times of oxygen and nitrogen in the atmosphere are used to compute total absorption. The resulting graphs of total absorption as a function of frequency for different humidities should be used in lieu of the graph published earlier by Evans et al (1972).

  9. Subgap Absorption in Conjugated Polymers

    DOE R&D Accomplishments Database

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  10. 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

  11. Ultraviolet absorption spectrum of HOCl

    NASA Technical Reports Server (NTRS)

    Burkholder, James B.

    1993-01-01

    The room temperature UV absorption spectrum of HOCl was measured over the wavelength range 200 to 380 nm with a diode array spectrometer. The absorption spectrum was identified from UV absorption spectra recorded following UV photolysis of equilibrium mixtures of Cl2O/H2O/HOCl. The HOCl spectrum is continuous with a maximum at 242 nm and a secondary peak at 304 nm. The measured absorption cross section at 242 nm was (2.1 +/- 0.3) x 10 exp -19/sq cm (2 sigma error limits). These results are in excellent agreement with the work of Knauth et al. (1979) but in poor agreement with the more recent measurements of Mishalanie et al. (1986) and Permien et al. (1988). An HOCl nu2 infrared band intensity of 230 +/- 35/sq cm atm was determined based on this UV absorption cross section. The present results are compared with these previous measurements and the discrepancies are discussed.

  12. Early Sexual Exploitation as an Influence in Prostitution.

    ERIC Educational Resources Information Center

    Silbert, Mimi H.; Pines, Ayala M.

    1983-01-01

    Surveyed 200 female street prostitutes to determine whether they were sexually exploited during childhood. Results showed 60 percent of the subjects were sexually exploited. The few girls who discussed their abuse with others were met with shame and most often inaction. Only 10 percent were abused by strangers. (JAC)

  13. 77 FR 36491 - Request for Information Regarding Senior Financial Exploitation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-19

    ... Senior Financial Exploitation AGENCY: Bureau of Consumer Financial Protection. ACTION: Request for...'') to facilitate the financial literacy of individuals aged 62 or older (``seniors''), on protection... Monica Jackson at 202-435-7275. For specific questions on senior financial exploitation, please call...

  14. 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,…

  15. Gas-absorption process

    DOEpatents

    Stephenson, Michael J.; Eby, Robert S.

    1978-01-01

    This invention is an improved gas-absorption process for the recovery of a desired component from a feed-gas mixture containing the same. In the preferred form of the invention, the process operations are conducted in a closed-loop system including a gas-liquid contacting column having upper, intermediate, and lower contacting zones. A liquid absorbent for the desired component is circulated through the loop, being passed downwardly through the column, regenerated, withdrawn from a reboiler, and then recycled to the column. A novel technique is employed to concentrate the desired component in a narrow section of the intermediate zone. This technique comprises maintaining the temperature of the liquid-phase input to the intermediate zone at a sufficiently lower value than that of the gas-phase input to the zone to effect condensation of a major part of the absorbent-vapor upflow to the section. This establishes a steep temperature gradient in the section. The stripping factors below this section are selected to ensure that virtually all of the gases in the downflowing absorbent from the section are desorbed. The stripping factors above the section are selected to ensure re-dissolution of the desired component but not the less-soluble diluent gases. As a result, a peak concentration of the desired component is established in the section, and gas rich in that component can be withdrawn therefrom. The new process provides important advantages. The chief advantage is that the process operations can be conducted in a single column in which the contacting zones operate at essentially the same pressure.

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

    PubMed

    Moustafa, Khaled

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. [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.

  18. 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

  19. 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.

  20. Gastrointestinal citrate absorption in nephrolithiasis

    NASA Technical Reports Server (NTRS)

    Fegan, J.; Khan, R.; Poindexter, J.; Pak, C. Y.

    1992-01-01

    Gastrointestinal absorption of citrate was measured in stone patients with idiopathic hypocitraturia to determine if citrate malabsorption could account for low urinary citrate. Citrate absorption was measured directly from recovery of orally administered potassium citrate (40 mEq.) in the intestinal lavage fluid, using an intestinal washout technique. In 7 stone patients citrate absorption, serum citrate levels, peak citrate concentration in serum and area under the curve were not significantly different from those of 7 normal subjects. Citrate absorption was rapid and efficient in both groups, with 96 to 98% absorbed within 3 hours. The absorption of citrate was less efficient from a tablet preparation of potassium citrate than from a liquid preparation, probably due to a delayed release of citrate from wax matrix. However, citrate absorption from solid potassium citrate was still high at 91%, compared to 98% for a liquid preparation. Thus, hypocitraturia is unlikely to be due to an impaired gastrointestinal absorption of citrate in stone patients without overt bowel disease.

  1. 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.

  2. 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. Copyright

  3. Broadband absorption with gradient metasurfaces

    NASA Astrophysics Data System (ADS)

    Kwon, Hoyeong; Chalabi, Hamidreza; Alù, Andrea

    2018-03-01

    A metasurface with appropriately designed transverse spatial inhomogeneities can provide the desired phase redistribution in response to an incident wave with arbitrary incident angle. This property of gradient metasurfaces has been used to modify light propagation in unusual manners, to transform the impinging optical wavefront with large flexibility. In this work, we show how gradient metasurfaces can be tailored to offer high absorption in thin absorptive layers, and how to design realistic metasurfaces for this purpose using dielectric materials.

  4. Differential absorption radar techniques: water vapor retrievals

    NASA Astrophysics Data System (ADS)

    Millán, Luis; Lebsock, Matthew; Livesey, Nathaniel; Tanelli, Simone

    2016-06-01

    Two radar pulses sent at different frequencies near the 183 GHz water vapor line can be used to determine total column water vapor and water vapor profiles (within clouds or precipitation) exploiting the differential absorption on and off the line. We assess these water vapor measurements by applying a radar instrument simulator to CloudSat pixels and then running end-to-end retrieval simulations. These end-to-end retrievals enable us to fully characterize not only the expected precision but also their potential biases, allowing us to select radar tones that maximize the water vapor signal minimizing potential errors due to spectral variations in the target extinction properties. A hypothetical CloudSat-like instrument with 500 m by ˜ 1 km vertical and horizontal resolution and a minimum detectable signal and radar precision of -30 and 0.16 dBZ, respectively, can estimate total column water vapor with an expected precision of around 0.03 cm, with potential biases smaller than 0.26 cm most of the time, even under rainy conditions. The expected precision for water vapor profiles was found to be around 89 % on average, with potential biases smaller than 77 % most of the time when the profile is being retrieved close to surface but smaller than 38 % above 3 km. By using either horizontal or vertical averaging, the precision will improve vastly, with the measurements still retaining a considerably high vertical and/or horizontal resolution.

  5. Conceptual model and map of financial exploitation of older adults.

    PubMed

    Conrad, Kendon J; Iris, Madelyn; Ridings, John W; Fairman, Kimberly P; Rosen, Abby; Wilber, Kathleen H

    2011-10-01

    This article describes the processes and outcomes of three-dimensional concept mapping to conceptualize financial exploitation of older adults. Statements were generated from a literature review and by local and national panels consisting of 16 experts in the field of financial exploitation. These statements were sorted and rated using Concept Systems software, which grouped the statements into clusters and depicted them as a map. Statements were grouped into six clusters, and ranked by the experts as follows in descending severity: (a) theft and scams, (b) financial victimization, (c) financial entitlement, (d) coercion, (e) signs of possible financial exploitation, and (f) money management difficulties. The hierarchical model can be used to identify elder financial exploitation and differentiate it from related but distinct areas of victimization. The severity hierarchy may be used to develop measures that will enable more precise screening for triage of clients into appropriate interventions.

  6. Human trafficking and exploitation: A global health concern.

    PubMed

    Zimmerman, Cathy; Kiss, Ligia

    2017-11-01

    In this collection review, Cathy Zimmerman and colleague introduce the PLOS Medicine Collection on Human Trafficking, Exploitation and Health, laying out the magnitude of the global trafficking problem and offering a public health policy framework to guide responses to trafficking.

  7. Fat-soluble vitamin intestinal absorption: absorption sites in the intestine and interactions for absorption.

    PubMed

    Goncalves, Aurélie; Roi, Stéphanie; Nowicki, Marion; Dhaussy, Amélie; Huertas, Alain; Amiot, Marie-Josèphe; Reboul, Emmanuelle

    2015-04-01

    The interactions occurring at the intestinal level between the fat-soluble vitamins A, D, E and K (FSVs) are poorly documented. We first determined each FSV absorption profile along the duodenal-colonic axis of mouse intestine to clarify their respective absorption sites. We then investigated the interactions between FSVs during their uptake by Caco-2 cells. Our data show that vitamin A was mostly absorbed in the mouse proximal intestine, while vitamin D was absorbed in the median intestine, and vitamin E and K in the distal intestine. Significant competitive interactions for uptake were then elucidated among vitamin D, E and K, supporting the hypothesis of common absorption pathways. Vitamin A also significantly decreased the uptake of the other FSVs but, conversely, its uptake was not impaired by vitamins D and K and even promoted by vitamin E. These results should be taken into account, especially for supplement formulation, to optimise FSV absorption. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Operational Decision Aids for Exploiting or Mitigating Electromagnetic Propagation Effects

    DTIC Science & Technology

    1989-09-01

    Exploitation or mitigation of environmental effects rank equal in importance with weapons systems. The rapidly changing propagation environment ...global in nature . It not only involves the ocean environment from the tropics to the poles, but also the coastal and land environments . Some of the...tactics must take environ - mental conditions into account and either mitigate or exploit their effects. There are many environmental factors that influence

  9. Rational Exploitation and Utilizing of Groundwater in Jiangsu Coastal Area

    NASA Astrophysics Data System (ADS)

    Kang, B.; Lin, X.

    2017-12-01

    Jiangsu coastal area is located in the southeast coast of China, where is a new industrial base and an important coastal and Land Resources Development Zone of China. In the areas with strong human exploitation activities, regional groundwater evolution is obviously affected by human activities. In order to solve the environmental geological problems caused by groundwater exploitation fundamentally, we must find out the forming conditions of regional groundwater hydrodynamic field, and the impact of human activities on groundwater hydrodynamic field evolution and hydrogeochemical evolition. Based on these results, scientific management and reasonable exploitation of the regional groundwater resources can be provided for the utilization. Taking the coastal area of Jiangsu as the research area, we investigate and analyze of the regional hydrogeological conditions. The numerical simulation model of groundwater flow was established according to the water power, chemical and isotopic methods, the conditions of water flow and the influence of hydrodynamic field on the water chemical field. We predict the evolution of regional groundwater dynamics under the influence of human activities and climate change and evaluate the influence of groundwater dynamic field evolution on the environmental geological problems caused by groundwater exploitation under various conditions. We get the following conclusions: Three groundwater exploitation optimal schemes were established. The groundwater salinization was taken as the primary control condition. The substitution model was proposed to model groundwater exploitation and water level changes by BP network method.Then genetic algorithm was used to solve the optimization solution. Three groundwater exploitation optimal schemes were submit to local water resource management. The first sheme was used to solve the groundwater salinization problem. The second sheme focused on dual water supply. The third sheme concerned on emergency water

  10. The ESA scientific exploitation element results and outlook

    NASA Astrophysics Data System (ADS)

    Desnos, Yves-louis; Regner, Peter; Delwart, Steven; Benveniste, Jerome; Engdahl, Marcus; Donlon, Craig; Mathieu, Pierre-Philippe; Fernandez, Diego; Gascon, Ferran; Zehner, Claus; Davidson, Malcolm; Goryl, Philippe; Koetz, Benjamin; Pinnock, Simon

    2017-04-01

    The Scientific Exploitation of Operational Missions (SEOM) element of ESA's fourth Earth Observation Envelope Programme (EOEP4) prime objective is to federate, support and expand the international research community built up over the last 25 years exploiting ESA's EO missions. SEOM enables the science community to address new scientific research areas that are opened by the free and open access to data from operational EO missions. Based on community-wide recommendations, gathered through a series of international thematic workshops and scientific user consultation meetings, key research studies have been launched over the last years to further exploit data from the Sentinels (http://seom.esa.int/). During 2016 several Science users consultation workshops have been organized, new results from scientific studies have been published and open-source multi-mission scientific toolboxes have been distributed (SNAP 80000 users from 190 countries). In addition the first ESA Massive Open Online Courses on Climate from space have been deployed (20000 participants) and the second EO Open Science conference was organized at ESA in September 2016 bringing together young EO scientists and data scientists. The new EOEP5 Exploitation element approved in 2016 and starting in 2017 is taking stock of all precursor activities in EO Open Science and Innovation and in particular a workplan for ESA scientific exploitation activities has been presented to Member States taking full benefit of the latest information and communication technology. The results and highlights from current scientific exploitation activities will be presented and an outlook on the upcoming activities under the new EOEP5 exploitation element will be given.

  11. Architecture for Absorption Based Heaters

    SciTech Connect

    Moghaddam, Saeed; Chugh, Devesh

    An absorption based heater is constructed on a fluid barrier heat exchanging plate such that it requires little space in a structure. The absorption based heater has a desorber, heat exchanger, and absorber sequentially placed on the fluid barrier heat exchanging plate. The vapor exchange faces of the desorber and the absorber are covered by a vapor permeable membrane that is permeable to a refrigerant vapor but impermeable to an absorbent. A process fluid flows on the side of the fluid barrier heat exchanging plate opposite the vapor exchange face through the absorber and subsequently through the heat exchanger. Themore » absorption based heater can include a second plate with a condenser situated parallel to the fluid barrier heat exchanging plate and opposing the desorber for condensation of the refrigerant for additional heating of the process fluid.« less

  12. Absorption of Orally Administered Hyaluronan.

    PubMed

    Kimura, Mamoru; Maeshima, Takuya; Kubota, Takumi; Kurihara, Hitoshi; Masuda, Yasunobu; Nomura, Yoshihiro

    2016-12-01

    Hyaluronan (HA) has been utilized as a supplement. However, the absorption of orally administrated HA remains controversial. The degradation and absorption of HA in the intestine were investigated in this study. HA excretion into the feces, degradation in the intestinal tract, absorption through the large intestine, and translocation to the blood and skin were examined. HA administered orally was not detected in rat feces. HA was degraded by cecal content, but not by artificial gastric juice and intestinal juice. Oligosaccharide HA passed through excised large intestine sacs. Furthermore, disaccharides, tetrasaccharides, and polysaccharides HA were distributed to the skin of rats following oral administration of high molecular weight HA (300 kDa). The results of the study suggest that orally administered HA is degraded to oligosaccharides by intestinal bacteria, and oligosaccharide HA is absorbed in the large intestine and is subsequently distributed throughout the tissues, including the skin.

  13. Thermodynamic derivatives of infrared absorptance

    NASA Technical Reports Server (NTRS)

    Broersma, S.; Walls, W. L.

    1974-01-01

    Calculation of the concentration, pressure, and temperature dependence of the spectral absorptance of a vibrational absorption band. A smooth thermodynamic dependence was found for wavelength intervals where the average absorptance is less than 0.65. Individual rotational lines, whose parameters are often well known, were used as bases in the calculation of medium resolution spectra. Two modes of calculation were combined: well-separated rotational lines plus interaction terms, or strongly overlapping lines that were represented by a compound line of similar shape plus corrections. The 1.9- and 6.3-micron bands of H2O and the 4.3-micron band of CO2 were examined in detail and compared with experiment.

  14. Enhanced absorption cycle computer model

    NASA Astrophysics Data System (ADS)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  15. Absorption-heat-pump system

    DOEpatents

    Grossman, G.; Perez-Blanco, H.

    1983-06-16

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  16. An Inexpensive Optical Absorption Experiment

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2006-09-01

    This optical absorption experiment can be put together in only a few minutes with materials found in most secondary or undergraduate stockrooms. The absorption material is the partly transparent flexible anti-static plastic material used to package solid-state devices. The detector is a hand-held photographic exposure meter of the type that was in common use before the advent of point-and-shoot cameras. A graph of the intensity of the transmitted light as a function of the number of sheets of the material is a decreasing exponential. The emphasis of the experiment is on the mathematical form.

  17. Two-photon absorption dispersion spectrometer for 1.53 μm eye-safe Doppler LIDAR.

    PubMed

    Vance, J D

    2012-07-01

    Based upon resonant two-photon absorption within a rubidium cell and 780 nm pump light, a birefringent medium for 1.530 μm is induced that changes rapidly with frequency. The birefringence is exploited to build a spectrometer that is capable of measuring the Doppler shift of scattered photons.

  18. Aerosol Absorption Measurements in MILAGRO.

    NASA Astrophysics Data System (ADS)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  19. Metal powder absorptivity: Modeling and experiment

    DOE PAGES

    Boley, C. D.; Mitchell, S. C.; Rubenchik, A. M.; ...

    2016-08-10

    Here, we present results of numerical modeling and direct calorimetric measurements of the powder absorptivity for a number of metals. The modeling results generally correlate well with experiment. We show that the powder absorptivity is determined, to a great extent, by the absorptivity of a flat surface at normal incidence. Our results allow the prediction of the powder absorptivity from normal flat-surface absorptivity measurements.

  20. Metal powder absorptivity: Modeling and experiment

    SciTech Connect

    Boley, C. D.; Mitchell, S. C.; Rubenchik, A. M.

    Here, we present results of numerical modeling and direct calorimetric measurements of the powder absorptivity for a number of metals. The modeling results generally correlate well with experiment. We show that the powder absorptivity is determined, to a great extent, by the absorptivity of a flat surface at normal incidence. Our results allow the prediction of the powder absorptivity from normal flat-surface absorptivity measurements.

  1. Estimation of water absorption coefficient using the TDR method

    NASA Astrophysics Data System (ADS)

    Suchorab, Zbigniew; Majerek, Dariusz; Brzyski, Przemysław; Sobczuk, Henryk; Raczkowski, Andrzej

    2017-07-01

    Moisture accumulation and transport in the building barriers is an important feature that influences building performance, causing serious exploitation problems as increased energy use, mold and bacteria growth, decrease of indoor air parameters that may lead to sick building syndrome (SBS). One of the parameters that is used to describe moisture characteristic of the material is water absorption coefficient being the measure of capillary behavior of the material as a function of time and the surface area of the specimen. As usual it is determined using gravimetric methods according to EN 1925:1999 standard. In this article we demonstrate the possibility of determination of water absorption coefficient of autoclaved aerated concrete (AAC) using the Time Domain Reflectometry (TDR) method. TDR is an electric technique that had been adopted from soil science and can be successfully used for real-time monitoring of moisture transport in building materials and envelopes. Data achieved using TDR readouts show high correlation with standard method of moisture absorptivity coefficient determination.

  2. 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.

  3. Micro-UAV tracking framework for EO exploitation

    NASA Astrophysics Data System (ADS)

    Browning, David; Wilhelm, Joe; Van Hook, Richard; Gallagher, John

    2012-06-01

    Historically, the Air Force's research into aerial platforms for sensing systems has focused on low-, mid-, and highaltitude platforms. Though these systems are likely to comprise the majority of the Air Force's assets for the foreseeable future, they have limitations. Specifically, these platforms, their sensor packages, and their data exploitation software are unsuited for close-quarter surveillance, such as in alleys and inside of buildings. Micro-UAVs have been gaining in popularity, especially non-fixed-wing platforms such as quad-rotors. These platforms are much more appropriate for confined spaces. However, the types of video exploitation techniques that can effectively be used are different from the typical nadir-looking aerial platform. This paper discusses the creation of a framework for testing existing and new video exploitation algorithms, as well as describes a sample micro-UAV-based tracker.

  4. Off-shoring clinical research: exploitation and the reciprocity constraint.

    PubMed

    Mitra, Agomoni Ganguli

    2013-12-01

    The last 20 years have seen a staggering growth in the practice of off-shoring clinical research to low-and middle-income countries (LICs and MICs), a growth that has been matched by the neoliberal policies adopted by host countries towards attracting trials to their shores. A recurring concern in this context is the charge of exploitation, linked to various aspects of off-shoring. In this paper, I examine Alan Wertheimer's approach and offer an alternative view of understanding exploitation in this context. I will suggest that the justification for the enterprise of research is largely dependent on its integration within a health system from which participants regularly benefit and I argue that an attention to a principle of reciprocity will enable us to better recognize and address exploitation in international research. © 2012 John Wiley & Sons Ltd.

  5. Aerosol Absorption and Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Stier, Philip; Seinfeld, J. H.; Kinne, Stefan; Boucher, Olivier

    2007-01-01

    We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006) significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the shortwave anthropogenic aerosol top-of-atmosphere (TOA) radiative forcing clear-sky from -0.79 to -0.53 W m(sup -2) (33%) and all-sky from -0.47 to -0.13W m(sup -2 (72%). Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19W m(sup -2) (36%) clear-sky and of 0.12W m(sup -2) (92%) all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05W m(sup -2) and a positive TOA forcing perturbation of 0

  6. A simple heat-pipe cell for X-ray absorption spectrometry of potassium vapor

    NASA Astrophysics Data System (ADS)

    Pres̆eren, R.; Kodre, A.; Arc̆on, I.; Padez̆nik Gomils̆ek, J.; Hribar, M.

    1999-01-01

    The construction and operation of a simple high-temperature X-ray absorption cell for potassium vapor is described. The principle of "spectroscopic heat pipe" is exploited to separate kapton windows, indispensable for good transmission in the low-energy region, from the hot and aggressive vapor. High-resolution spectrum of the K-edge region of atomic potassium reveals fingerprints of multielectron photoexcitations.

  7. Final Report, “Exploiting Global View for Resilience”

    SciTech Connect

    Chien, Andrew

    2017-03-29

    Final technical report for the "Exploiting Global View for Resilience" project. The GVR project aims to create a new approach to portable, resilient applications. The GVR approach builds on a global view data model,, adding versioning (multi-version), user control of timing and rate (multi-stream), and flexible cross layer error signalling and recovery. With a versioned array as a portable abstraction, GVR enables application programmers to exploit deep scientific and application code insights to manage resilience (and its overhead) in a flexible, portable fashion.

  8. Content-based image exploitation for situational awareness

    NASA Astrophysics Data System (ADS)

    Gains, David

    2008-04-01

    Image exploitation is of increasing importance to the enterprise of building situational awareness from multi-source data. It involves image acquisition, identification of objects of interest in imagery, storage, search and retrieval of imagery, and the distribution of imagery over possibly bandwidth limited networks. This paper describes an image exploitation application that uses image content alone to detect objects of interest, and that automatically establishes and preserves spatial and temporal relationships between images, cameras and objects. The application features an intuitive user interface that exposes all images and information generated by the system to an operator thus facilitating the formation of situational awareness.

  9. Exploiting Thread Parallelism for Ocean Modeling on Cray XC Supercomputers

    SciTech Connect

    Sarje, Abhinav; Jacobsen, Douglas W.; Williams, Samuel W.

    The incorporation of increasing core counts in modern processors used to build state-of-the-art supercomputers is driving application development towards exploitation of thread parallelism, in addition to distributed memory parallelism, with the goal of delivering efficient high-performance codes. In this work we describe the exploitation of threading and our experiences with it with respect to a real-world ocean modeling application code, MPAS-Ocean. We present detailed performance analysis and comparisons of various approaches and configurations for threading on the Cray XC series supercomputers.

  10. The Exploitation of the Electric Contributions in Infrared Power Generation

    DTIC Science & Technology

    2016-02-02

    Technical Report for year one 3. DATES COVERED (From - To) 3/10/2015-2/2/16 4. TITLE AND SUBTITLE The exploitation of the electric contributions in...establishes a method to harvest infrared radiation and transform it into usable energy. We have identified an electrical contribution to the energy...area code) (540) 568-8857 ^olko^ögüöo Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 The exploitation of the electric contributions

  11. Colloidal quantum dot solar cells exploiting hierarchical structuring.

    PubMed

    Labelle, André J; Thon, Susanna M; Masala, Silvia; Adachi, Michael M; Dong, Haopeng; Farahani, Maryam; Ip, Alexander H; Fratalocchi, Andrea; Sargent, Edward H

    2015-02-11

    Extremely thin-absorber solar cells offer low materials utilization and simplified manufacture but require improved means to enhance photon absorption in the active layer. Here, we report enhanced-absorption colloidal quantum dot (CQD) solar cells that feature transfer-stamped solution-processed pyramid-shaped electrodes employed in a hierarchically structured device. The pyramids increase, by up to a factor of 2, the external quantum efficiency of the device at absorption-limited wavelengths near the absorber band edge. We show that absorption enhancement can be optimized with increased pyramid angle with an appreciable net improvement in power conversion efficiency, that is, with the gain in current associated with improved absorption and extraction overcoming the smaller fractional decrease in open-circuit voltage associated with increased junction area. We show that the hierarchical combination of micron-scale structured electrodes with nanoscale films provides for an optimized enhancement at absorption-limited wavelengths. We fabricate 54.7° pyramid-patterned electrodes, conformally apply the quantum dot films, and report pyramid CQD solar cells that exhibit a 24% improvement in overall short-circuit current density with champion devices providing a power conversion efficiency of 9.2%.

  12. 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

  13. 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.

  14. Exploiting Patient Labour at Kew Cottages, Australia, 1887-1950

    ERIC Educational Resources Information Center

    Monk, Lee-Ann

    2010-01-01

    This article examines the exploitation of patient labour at Kew Cottages, Australia's first purpose-built state institution for people with learning disabilities. Analysing historical evidence for the period 1887-1950 shows that unpaid patient labour contributed significantly to the economy of the Cottages and so to the government department of…

  15. 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.…

  16. Reproductive characteristics of a coyote population before and during exploitation

    Treesearch

    John C. Kilgo; Christopher E. Shaw; Mark Vukovich; Michael J. Conroy; Charles Ruth

    2017-01-01

    The eastward expansion of coyotes (Canis latrans) has brought the species into ecosystems and landscapes different from those it historically occupied, yet little is known about the reproductive biology of coyotes in the southeastern United States or the effects of exploitation on reproduction in coyotes. Our objective was to quantify litter size,...

  17. 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…

  18. 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.

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

    DTIC Science & Technology

    2015-05-01

    Together with Strata’s fine-grained confinement, they build up a robust sandbox environment for SOUP that can resist most kind of exploits...Guide to the World’s Most Popular Disassembler. 2008: No Starch Press. 60. Christey, S., 2011 CWE/SANS top 25 most dangerous software errors

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

    PubMed Central

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

    2009-01-01

    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. PMID:19139416

  1. 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.

  2. Exploiting Formation Flying for Fuel Saving Supersonic Oblique Wing Aircraft

    DTIC Science & Technology

    2007-07-01

    used and developed during recent wing / winglet / morphing design programmes (Refs.13-14). By exploiting this method, we have assessed the aerodynamics...with winglets ”, AIAA-2006-3460. 25th Applied Aero Conference, San Francisco, June 2006. 15. NANGIA, R.K., PALMER, M.E., “Formation Flying of Commercial

  3. 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.

  4. Bats track and exploit changes in insect pest populations

    USDA-ARS?s Scientific Manuscript database

    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...

  5. Desiring TESOL and International Education: Market Abuse and Exploitation

    ERIC Educational Resources Information Center

    Chowdhury, Raqib; Ha, Phan Le

    2014-01-01

    This book addresses how Western universities have constructed themselves as global providers of education, and are driven to be globally competitive. It examines how the term "international" has been exploited by the market in the form of government educational policies and agencies, host institutions, academia and the mass media. The…

  6. 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.…

  7. 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…

  8. Grooming Cybervictims: The Psychosocial Effects of Online Exploitation for Youth.

    ERIC Educational Resources Information Center

    Berson, Ilene R.

    2003-01-01

    Presents an overview of the benefits and risks of Web-based interactions for youth. Discusses, as an illustrative example, the psychosocial effects of online "grooming" practices that are designed to lure and exploit children by enticing them, typically in a nonsexual way, toward a sexual encounter. Suggests constructive solutions and a…

  9. Iodine Absorption Cells Purity Testing.

    PubMed

    Hrabina, Jan; Zucco, Massimo; Philippe, Charles; Pham, Tuan Minh; Holá, Miroslava; Acef, Ouali; Lazar, Josef; Číp, Ondřej

    2017-01-06

    This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions' spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches).

  10. Ultraviolet absorption experiment MA-059

    NASA Technical Reports Server (NTRS)

    Donahue, T. M.; Hudson, R. D.; Anderson, J.; Kaufman, F.; Mcelroy, M. B.

    1976-01-01

    The ultraviolet absorption experiment performed during the Apollo Soyuz mission involved sending a beam of atomic oxygen and atomic nitrogen resonance radiation, strong unabsorbable oxygen and nitrogen radiation, and visual radiation, all filling the same 3 deg-wide field of view from the Apollo to the Soyuz. The radiation struck a retroreflector array on the Soyuz and was returned to a spectrometer onboard the Apollo. The density of atomic oxygen and atomic nitrogen between the two spacecraft was measured by observing the amount of resonance radiation absorbed when the line joining Apollo and Soyuz was perpendicular to their velocity with respect to the ambient atmosphere. Information concerning oxygen densities was also obtained by observation of resonantly fluorescent light. The absorption experiments for atomic oxygen and atomic nitrogen were successfully performed at a range of 500 meters, and abundant resonance fluorescence data were obtained.

  11. Landing gear energy absorption system

    NASA Technical Reports Server (NTRS)

    Hansen, Christopher P. (Inventor)

    1994-01-01

    A landing pad system is described for absorbing horizontal and vertical impact forces upon engagement with a landing surface where circumferentially arranged landing struts respectively have a clevis which receives a slidable rod member and where the upper portion of a slidable rod member is coupled to the clevis by friction washers which are force fit onto the rod member to provide for controlled constant force energy absorption when the rod member moves relative to the clevis. The lower end of the friction rod is pivotally attached by a ball and socket to a support plate where the support plate is arranged to slide in a transverse direction relative to a housing which contains an energy absorption material for absorbing energy in a transverse direction.

  12. AERONET derived (BC) aerosol absorption

    NASA Astrophysics Data System (ADS)

    Kinne, S.

    2015-12-01

    AERONET is a ground-based sun-/sky-photometer network with good annual statistics at more than 400 sites worldwide. Inversion methods applied to these data define all relevant column aerosol optical properties and reveal even microphysical detail. The extracted data include estimates for aerosol size-distributions and for aerosol refractive indices at four different solar wavelengths. Hereby, the imaginary parts of the refractive indices define the aerosol column absorption. For regional and global averages and radiative impact assessment with off-line radiative transfer, these local data have been extended with distribution patterns offered by AeroCom modeling experiments. Annual and seasonal absorption distributions for total aerosol and estimates for component contributions (such as BC) are presented and associated direct forcing impacts are quantified.

  13. Elder Fraud and Financial Exploitation: Application of Routine Activity Theory.

    PubMed

    DeLiema, Marguerite

    2017-03-10

    Elder financial exploitation, committed by individuals in positions of trust, and elder fraud, committed by predatory strangers, are two forms of financial victimization that target vulnerable older adults. This study analyzes differences between fraud and financial exploitation victims and tests routine activity theory as a contextual model for victimization. Routine activity theory predicts that criminal opportunities arise when a motivated offender and suitable target meet in the absence of capable guardians. Fifty-three financial exploitation and fraud cases were sampled from an elder abuse forensic center. Data include law enforcement and caseworker investigation reports, victim medical records, perpetrator demographic information, and forensic assessments of victim health and cognitive functioning. Fraud and financial exploitation victims performed poorly on tests of cognitive functioning and financial decision making administered by a forensic neuropsychologist following the allegations. Based on retrospective record review, there were few significant differences in physical health and cognitive functioning at the time victims' assets were taken, although their social contexts were different. Significantly more fraud victims were childless compared with financial exploitation victims. Fraud perpetrators took advantage of elders when they had no trustworthy friends or relatives to safeguard their assets. Findings support an adapted routine activity theory as a contextual model for financial victimization. Fraud most often occurred when a vulnerable elder was solicited by a financial predator in the absence of capable guardians. Prevention efforts should focus on reducing social isolation to enhance protection. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Photodetector with enhanced light absorption

    DOEpatents

    Kane, James

    1985-01-01

    A photodetector including a light transmissive electrically conducting layer having a textured surface with a semiconductor body thereon. This layer traps incident light thereby enhancing the absorption of light by the semiconductor body. A photodetector comprising a textured light transmissive electrically conducting layer of SnO.sub.2 and a body of hydrogenated amorphous silicon has a conversion efficiency about fifty percent greater than that of comparative cells. The invention also includes a method of fabricating the photodetector of the invention.

  15. All-optical reservoir computer based on saturation of absorption.

    PubMed

    Dejonckheere, Antoine; Duport, François; Smerieri, Anteo; Fang, Li; Oudar, Jean-Louis; Haelterman, Marc; Massar, Serge

    2014-05-05

    Reservoir computing is a new bio-inspired computation paradigm. It exploits a dynamical system driven by a time-dependent input to carry out computation. For efficient information processing, only a few parameters of the reservoir needs to be tuned, which makes it a promising framework for hardware implementation. Recently, electronic, opto-electronic and all-optical experimental reservoir computers were reported. In those implementations, the nonlinear response of the reservoir is provided by active devices such as optoelectronic modulators or optical amplifiers. By contrast, we propose here the first reservoir computer based on a fully passive nonlinearity, namely the saturable absorption of a semiconductor mirror. Our experimental setup constitutes an important step towards the development of ultrafast low-consumption analog computers.

  16. An integrated photo-thermal sensing system for rapid and direct diagnosis of anemia.

    PubMed

    Kwak, Bong Seop; Kim, Hyung Joon; Kim, Hyun Ok; Jung, Hyo-Il

    2010-12-15

    This article presents a thermal biosensor to diagnose the anemia without chemical treatments using temperature increase of red blood cells (RBC) when hemoglobin molecules absorb specific wavelength of photons and convert them to thermal energy. For measuring temperature change of red blood cell, the micro-scaled platinum resistance temperature detector (Pt RTD) was developed. For maintenance of constant ambient temperature, we designed and fabricated a thermostat system. The thermostat system consists of a K-type thermocouple and two electric heaters that serve to increase the system temperature, which is monitored by the thermocouple. Both heaters and the thermocouple were connected to a proportional-integral-derivative (PID) controller and enabled to maintain the temperature constant (<±0.1°C). For specific heating of red blood cell, 8.0 W/cm(2) diode pumped solid state (DPSS) continuous wave (CW) laser module was used with 532 nm wavelength. Using this system, we successfully measured the temperature variations (from 66.33±2.72°C to 74.16±2.06°C) of whole blood samples from 10 anemic patients and subsequently determined the concentration of hemoglobin (from 7.2 g/dL to 9.8 g/dL). The method proposed in this paper requires significantly less amount of whole blood sample (6 μl) compared with the conventional methods (175 μl) and allows instantaneous diagnosis (3 s) of anemia. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. [Study of blood sedimentation by photo-thermal radiometry with random excitation].

    PubMed

    Antoniow, J S; Marx, J; Egee, M; Droulle, C; Potron, G

    1994-01-01

    The erythrocyte sedimentation rate is a complex phenomena involving a large number of parameters. The rate of sedimentation is highly dependent on the haematocrit, the internal viscosity of the red cells and the viscosity of the suspending medium and its composition. The experimental conditions also have a non-negligible effect (geometry and nature of the test tube, temperature, foreign substances in the medium...). In order to respond to the need for more precise and more rapid methods of analyzing the erythrocyte sedimentation rate, we developed new physical methods allowing a real time evaluation of the phenomena involved. Several of these new photothermal methods have already been applied for non-destructive evaluation of thin or layered material (such as composite material or glued structures) both in laboratory situations and in the industry. When a material is placed in a modulated laser beam, the incident rays absorbed heat the sample. The heat then diffuses throughout the material and the surface temperature of the sample increases locally with a periodicity. The surface thus emits a modulated flow of infrared radiation. The amplitude and phase shift of the photothermal signal generated is characteristically dependent of the optic and thermal properties of the material for a given modulation frequency. The early photothermal modelling based on a two-layer model and a physico-mathematical theory of red cell sedimentation proposed by S. Oka made it possible to simulate the phenomena as they occur over time. We hypothesize that the temperature gradients created within the sample are too small to create a convection current and that the all heat transfer occurs by conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Improving nanoparticle diffusion through tumor collagen matrix by photo-thermal gold nanorods

    NASA Astrophysics Data System (ADS)

    Raeesi, Vahid; Chan, Warren C. W.

    2016-06-01

    Collagen (I) impairs the targeting of nanoparticles to tumor cells by obstructing their diffusion inside dense tumor interstitial matrix. This potentially makes large nanoparticles (>50 nm) reside near the tumor vessels and thereby compromises their functionality. Here we propose a strategy to locally improve nanoparticle transport inside collagen (I) component of the tumor tissue. We first used heat generating gold nanorods to alter collagen (I) matrix by local temperature elevation. We then explored this impact on the transport of 50 nm and 120 nm inorganic nanoparticles inside collagen (I). We demonstrated an increase in average diffusivity of 50 nm and 120 nm in the denatured collagen (I) by ~14 and ~21 fold, respectively, compared to intact untreated collagen (I) matrix. This study shows how nanoparticle-mediated hyperthermia inside tumor tissue can improve the transport of large nanoparticles through collagen (I) matrix. The ability to increase nanoparticles diffusion inside tumor stroma allows their targeting or other functionalities to take effect, thereby significantly improving cancer therapeutic or diagnostic outcome.Collagen (I) impairs the targeting of nanoparticles to tumor cells by obstructing their diffusion inside dense tumor interstitial matrix. This potentially makes large nanoparticles (>50 nm) reside near the tumor vessels and thereby compromises their functionality. Here we propose a strategy to locally improve nanoparticle transport inside collagen (I) component of the tumor tissue. We first used heat generating gold nanorods to alter collagen (I) matrix by local temperature elevation. We then explored this impact on the transport of 50 nm and 120 nm inorganic nanoparticles inside collagen (I). We demonstrated an increase in average diffusivity of 50 nm and 120 nm in the denatured collagen (I) by ~14 and ~21 fold, respectively, compared to intact untreated collagen (I) matrix. This study shows how nanoparticle-mediated hyperthermia inside tumor tissue can improve the transport of large nanoparticles through collagen (I) matrix. The ability to increase nanoparticles diffusion inside tumor stroma allows their targeting or other functionalities to take effect, thereby significantly improving cancer therapeutic or diagnostic outcome. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08463f

  19. Calibrating the photo-thermal response of magneto-fluorescent gold nanoshells.

    PubMed

    Biswal, Nrusingh C; Ayala-Orzoco, Ciceron; Halas, Naomi J; Joshi, Amit

    2011-01-01

    We report the photothermal response and Near Infrared (NIR) imaging sensitivities of magneto-fluorescent silica core gold nanocomplexes designed for molecular image guided thermal therapy of cancer. Approximately 160 nm Silica core gold nanoshells were designed to provide NIR fluorescent and Magnetic Resonance (MR) contrast by incorporating FDA approved dye indocyanine green (ICG) and iron-oxide within an outer silica epilayer. The imaging and therapeutic sensitivity, and the stability of fluorescence contrast for 12 microliters of suspension (containing approximately 7.9 × 10(8) or 1.3 femtoMole nanoshells) buried at depths of 2-8 mm in tissue mimicking scattering media is reported.

  20. Absorption characteristics of forest fire particulate matter

    Treesearch

    E.M. Patterson; Charles K. McMahon

    1984-01-01

    Abstract. Absorption properties of smokes from laboratory fires that represent prescription hums in the Southern states have been quantified to relate variations in measured absorption parameters to variation in fire conditions and to estimate emission factors for elemental carbon. Results showed significant differences in absorption of the smoke...

  1. Exploiting Social Media Sensor Networks through Novel Data Fusion Techniques

    SciTech Connect

    Kouri, Tina

    Unprecedented amounts of data are continuously being generated by sensors (“hard” data) and by humans (“soft” data), and this data needs to be exploited to its full potential. The first step in exploiting this data is determine how the hard and soft data are related to each other. In this project we fuse hard and soft data, using the attributes of each (e.g., time and space), to gain more information about interesting events. Next, we attempt to use social networking textual data to predict the present (i.e., predict that an interesting event is occurring and details about the event) usingmore » data mining, machine learning, natural language processing, and text analysis techniques.« less

  2. Advanced regenerative absorption refrigeration cycles

    DOEpatents

    Dao, Kim

    1990-01-01

    Multi-effect regenerative absorption cycles which provide a high coefficient of performance (COP) at relatively high input temperatures. An absorber-coupled double-effect regenerative cycle (ADR cycle) (10) is provided having a single-effect absorption cycle (SEA cycle) (11) as a topping subcycle and a single-effect regenerative absorption cycle (1R cycle) (12) as a bottoming subcycle. The SEA cycle (11) includes a boiler (13), a condenser (21), an expansion device (28), an evaporator (31), and an absorber (40), all operatively connected together. The 1R cycle (12) includes a multistage boiler (48), a multi-stage resorber (51), a multisection regenerator (49) and also uses the condenser (21), expansion device (28) and evaporator (31) of the SEA topping subcycle (11), all operatively connected together. External heat is applied to the SEA boiler (13) for operation up to about 500 degrees F., with most of the high pressure vapor going to the condenser (21) and evaporator (31) being generated by the regenerator (49). The substantially adiabatic and isothermal functioning of the SER subcycle (12) provides a high COP. For higher input temperatures of up to 700 degrees F., another SEA cycle (111) is used as a topping subcycle, with the absorber (140) of the topping subcycle being heat coupled to the boiler (13) of an ADR cycle (10). The 1R cycle (12) itself is an improvement in that all resorber stages (50b-f) have a portion of their output pumped to boiling conduits (71a-f) through the regenerator (49), which conduits are connected to and at the same pressure as the highest pressure stage (48a) of the 1R multistage boiler (48).

  3. 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

  4. N-CET: Network-Centric Exploitation and Tracking

    DTIC Science & Technology

    2009-10-01

    DATES COVERED (From - To) October 2008 – August 2009 4 . TITLE AND SUBTITLE N-CET: NETWORK – CENTRIC EXPLOITATION AND TRACKING 5a. CONTRACT NUMBER...At the core of N-CET are information management services that decouple data producers and consumers , allowing reconfiguration to suit mission needs...Shown around the head-node are different pieces of hardware including the Sony PlayStation R©3 (PS3) nodes used for computationally demanding tasks

  5. Transformation-aware Exploit Generation using a HI-CFG

    DTIC Science & Technology

    2013-05-16

    testing has many limitations of its own: it can require significant target -specific setup to perform well; it is unlikely to trigger vulnerabilities...check fails represents a potential vulnerability, but a conservative analysis can produce false positives , so we can use exploit generation to find...warnings that correspond to true positives . We can also find potentially vulnerable instructions in the course of a manual binary- level security audit

  6. Exploitation, autonomy, and the case for organ sales.

    PubMed

    Hughes, P M

    1998-01-01

    A recent argument in favor of a free market in human organs claims that such a market enhances personal autonomy. I argue here that such a market would, on the contrary, actually compromise the autonomy of those most likely to sell their organs, namely, the least well off members of society. A Marxian-inspired notion of exploitation is deployed to show how, and in what sense, this is the case.

  7. NEUTRON ABSORPTION AND SHIELDING DEVICE

    DOEpatents

    Axelrad, I.R.

    1960-06-21

    A neutron absorption and shielding device is described which is adapted for mounting in a radiation shielding wall surrounding a radioactive area through which instrumentation leads and the like may safely pass without permitting gamma or neutron radiation to pass to the exterior. The shielding device comprises a container having at least one nonrectilinear tube or passageway means extending therethrough, which is adapted to contain instrumentation leads or the like, a layer of a substance capable of absorbing gamma rays, and a solid resinous composition adapted to attenuate fast-moving neutrons and capture slow- moving or thermal neutrons.

  8. Microwave Absorption Characteristics of Tire

    NASA Astrophysics Data System (ADS)

    Zhang, Yuzhe; Hwang, Jiann-Yang; Peng, Zhiwei; Andriese, Matthew; Li, Bowen; Huang, Xiaodi; Wang, Xinli

    The recycling of waste tires has been a big environmental problem. About 280 million waste tires are produced annually in the United States and more than 2 billion tires are stockpiled, which cause fire hazards and health issues. Tire rubbers are insoluble elastic high polymer materials. They are not biodegradable and may take hundreds of years to decompose in the natural environment. Microwave irradiation can be a thermal processing method for the decomposition of tire rubbers. In this study, the microwave absorption properties of waste tire at various temperatures are characterized to determine the conditions favorable for the microwave heating of waste tires.

  9. Carbon Dioxide Absorption Heat Pump

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    2002-01-01

    A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

  10. 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.

  11. 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

  12. Sentinel-1 data exploitation for geohazard activity map generation

    NASA Astrophysics Data System (ADS)

    Barra, Anna; Solari, Lorenzo; Béjar-Pizarro, Marta; Monserrat, Oriol; Herrera, Gerardo; Bianchini, Silvia; Crosetto, Michele; María Mateos, Rosa; Sarro, Roberto; Moretti, Sandro

    2017-04-01

    This work is focused on geohazard mapping and monitoring by exploiting Sentinel-1 (A and B) data and the DInSAR (Differential interferometric SAR (Synthetic Aperture Radar)) techniques. Sometimes the interpretation of the DInSAR derived product (like the velocity map) can be complex, mostly for a final user who do not usually works with radar. The aim of this work is to generate, in a rapid way, a clear product to be easily exploited by the authorities in the geohazard management: intervention planning and prevention activities. Specifically, the presented methodology has been developed in the framework of the European project SAFETY, which is aimed at providing Civil Protection Authorities (CPA) with the capability of periodically evaluating and assessing the potential impact of geohazards (volcanic activity, earthquakes, landslides and subsidence) on urban areas. The methodology has three phases, the interferograms generation, the activity map generation, in terms of velocity and accumulated deformation (with time-series), and the Active Deformation Area (ADA) map generation. The last one is the final product, derived from the original activity map by analyzing the data in a Geographic Information System (GIS) environment, which isolate only the true deformation areas over the noise. This product can be more easily read by the authorities than the original activity map, i.e. can be better exploited to integrate other information and analysis. This product also permit an easy monitoring of the active areas.

  13. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. 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.

  15. Commercial sexual exploitation and sex trafficking of adolescents.

    PubMed

    Chung, Richard J; English, Abigail

    2015-08-01

    This review describes the current state of commercial sexual exploitation and sex trafficking of adolescents in the United States and globally, the legal and health implications of this severe form of abuse, and the roles that pediatric and adolescent healthcare providers can play in addressing this issue. Although this form of exploitation and abuse is shrouded in secrecy, pediatric and adolescent healthcare providers are well positioned to respond when it arises. However, awareness and understanding of the issue are generally lacking among healthcare professionals, currently limiting their effectiveness in combating this problem. Although the empirical evidence base available to guide clinical care of victims of trafficking remains limited given the secretive nature of the abuse, important contributions to the multidisciplinary literature on this issue have been made in recent years, including the Institute of Medicine's landmark report in the United States. Commercial sexual exploitation and sex trafficking of adolescents represent a human rights tragedy that remains inadequately addressed. As preeminent advocates for the health and well-being of adolescents, pediatric and adolescent healthcare providers can play a crucial role in advancing efforts not only to intervene but also to prevent further victimization of vulnerable youth.

  16. Relativistic Quantum Metrology: Exploiting relativity to improve quantum measurement technologies

    PubMed Central

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

    2014-01-01

    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. PMID:24851858

  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. 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.

  19. Tunneling induced absorption with competing Nonlinearities

    PubMed Central

    Peng, Yandong; Yang, Aihong; Xu, Yan; Wang, Peng; Yu, Yang; Guo, Hongju; Ren, Tingqi

    2016-01-01

    We investigate tunneling induced nonlinear absorption phenomena in a coupled quantum-dot system. Resonant tunneling causes constructive interference in the nonlinear absorption that leads to an increase of more than an order of magnitude over the maximum absorption in a coupled quantum dot system without tunneling. Resonant tunneling also leads to a narrowing of the linewidth of the absorption peak to a sublinewidth level. Analytical expressions show that the enhanced nonlinear absorption is largely due to the fifth-order nonlinear term. Competition between third- and fifth-order nonlinearities leads to an anomalous dispersion of the total susceptibility. PMID:27958303

  20. Tunneling induced absorption with competing Nonlinearities.

    PubMed

    Peng, Yandong; Yang, Aihong; Xu, Yan; Wang, Peng; Yu, Yang; Guo, Hongju; Ren, Tingqi

    2016-12-13

    We investigate tunneling induced nonlinear absorption phenomena in a coupled quantum-dot system. Resonant tunneling causes constructive interference in the nonlinear absorption that leads to an increase of more than an order of magnitude over the maximum absorption in a coupled quantum dot system without tunneling. Resonant tunneling also leads to a narrowing of the linewidth of the absorption peak to a sublinewidth level. Analytical expressions show that the enhanced nonlinear absorption is largely due to the fifth-order nonlinear term. Competition between third- and fifth-order nonlinearities leads to an anomalous dispersion of the total susceptibility.

  1. Five-Photon Absorption and Selective Enhancement of Multiphoton Absorption Processes

    PubMed Central

    2015-01-01

    We study one-, two-, three-, four-, and five-photon absorption of three centrosymmetric molecules using density functional theory. These calculations are the first ab initio calculations of five-photon absorption. Even- and odd-order absorption processes show different trends in the absorption cross sections. The behavior of all even- and odd-photon absorption properties shows a semiquantitative similarity, which can be explained using few-state models. This analysis shows that odd-photon absorption processes are largely determined by the one-photon absorption strength, whereas all even-photon absorption strengths are largely dominated by the two-photon absorption strength, in both cases modulated by powers of the polarizability of the final excited state. We demonstrate how to selectively enhance a specific multiphoton absorption process. PMID:26120588

  2. Five-Photon Absorption and Selective Enhancement of Multiphoton Absorption Processes.

    PubMed

    Friese, Daniel H; Bast, Radovan; Ruud, Kenneth

    2015-05-20

    We study one-, two-, three-, four-, and five-photon absorption of three centrosymmetric molecules using density functional theory. These calculations are the first ab initio calculations of five-photon absorption. Even- and odd-order absorption processes show different trends in the absorption cross sections. The behavior of all even- and odd-photon absorption properties shows a semiquantitative similarity, which can be explained using few-state models. This analysis shows that odd-photon absorption processes are largely determined by the one-photon absorption strength, whereas all even-photon absorption strengths are largely dominated by the two-photon absorption strength, in both cases modulated by powers of the polarizability of the final excited state. We demonstrate how to selectively enhance a specific multiphoton absorption process.

  3. Iron Absorption in Drosophila melanogaster

    PubMed Central

    Mandilaras, Konstantinos; Pathmanathan, Tharse; Missirlis, Fanis

    2013-01-01

    The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import), the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export) and the role of ferritin in the process of iron acquisition (iron storage). We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration. PMID:23686013

  4. Percutaneous absorption of selenium sulfide

    SciTech Connect

    Farley, J.; Skelly, E.M.; Weber, C.B.

    1986-01-01

    The purpose of this study was to determine selenium levels in the urine of Tinea patients before and after overnight application of a 2.5% selenium sulfide lotion. Selenium was measured by atomic absorption spectroscopy (AAS). Hydride generation and carbon rod atomization were studied. It was concluded from this study that selenium is absorbed through intact skin. Selenium is then excreted, at least partially, in urine, for at least a week following treatment. The data show that absorption and excretion of selenium vary on an individual basis. Selenium levels in urine following a single application of selenium sulfide lotion do notmore » indicate that toxic amounts of selenium are being absorbed. Repeated treatments with SeS/sub 2/ result in selenium concentrations in urine which are significantly higher than normal. Significant matrix effects are observed in the carbon rod atomization of urine samples for selenium determinations, even in the presence of a matrix modifier such as nickel. The method of standard additions is required to obtain accurate results in the direct determination of selenium in urine by carbon rod AAS.« less

  5. Iodine Absorption Cells Purity Testing

    PubMed Central

    Hrabina, Jan; Zucco, Massimo; Philippe, Charles; Pham, Tuan Minh; Holá, Miroslava; Acef, Ouali; Lazar, Josef; Číp, Ondřej

    2017-01-01

    This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions’ spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches). PMID:28067834

  6. QED-driven laser absorption

    NASA Astrophysics Data System (ADS)

    Levy, Matthew; Blackburn, T.; Ratan, N.; Sadler, J.; Ridgers, C.; Kasim, M.; Ceurvorst, L.; Holloway, J.; Baring, M.; Bell, A.; Glenzer, S.; Gregori, G.; Ilderton, A.; Marklund, M.; Tabak, M.; Wilks, S.; Norreys, P.

    2016-10-01

    Absorption covers the physical processes which convert intense photon flux into energetic particles when a high-power laser (I >1018 W cm-2 where I is intensity at 1 μm wavelength) illuminates optically-thick matter. It underpins important applications of petawatt laser systems today, e.g., in isochoric heating of materials. Next-generation lasers such as ELI are anticipated to produce quantum electrodynamical (QED) bursts of γ-rays and anti-matter via the multiphoton Breit-Wheeler process which could enable scaled laboratory probes, e.g., of black hole winds. Here, applying strong-field QED to advances in plasma kinematic theory, we present a model elucidating absorption limited only by an avalanche of self-created electron-positron pairs at ultra-high-field. The model, confirmed by multidimensional QED-PIC simulations, works over six orders of magnitude in optical intensity and reveals this cascade is initiated at 1.8 x 1025 W cm-2 using a realistic linearly-polarized laser pulse. Here the laser couples its energy into highly-collimated electrons, ions, γ-rays, and positrons at 12%, 6%, 58% and 13% efficiency, respectively. We remark on attributes of the QED plasma state and possible applications.

  7. Sulphate absorption across biological membranes.

    PubMed

    Mitchell, Stephen C; Waring, Rosemary H

    2016-01-01

    1. Sulphonation is unusual amongst the common Phase II (condensation; synthetic) reactions experienced by xenobiotics, in that the availability of the conjugating agent, sulphate, may become a rate-limiting factor. This sulphate is derived within the body via the oxygenation of sulphur moieties liberated from numerous ingested compounds including the sulphur-containing amino acids. Preformed inorganic sulphate also makes a considerable contribution to this pool. 2. There has been a divergence of opinion as to whether or not inorganic sulphate may be readily absorbed from the gastrointestinal tract and this controversy still continues in some quarters. Even more so, is the vexing question of potential absorption of inorganic sulphate via the lungs and through the skin. 3. This review examines the relevant diverse literature and concludes that sulphate ions may move across biological membranes by means of specific transporters and, although the gastrointestinal tract is by far the major portal of entry, some absorption across the lungs and the skin may take place under appropriate circumstances.

  8. Multistage quantum absorption heat pumps.

    PubMed

    Correa, Luis A

    2014-04-01

    It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N-2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration.

  9. Sound absorption with green materials

    NASA Astrophysics Data System (ADS)

    Trematerra, Amelia; Lombardi, Ilaria

    2017-07-01

    Green materials are a valid alternative to traditional materials that are by-products of processing oil. At the end of their useful life, green materials can be disposed of without polluting the environment. They are now being used in the construction and automotive industries. While, studies are currently being carried out in the aviation sector on the use of green materials for non-structural components of airplanes. Green materials can be used to improve the acoustic comfort inside buildings as well as mitigate reverberation, echoes effects and reduce the transmission of noise between rooms. In this paper, the acoustic measurements of the properties of green materials are reported. The absorption coefficient of samples of the materials were measured in the frequency range from 200 Hz to 2,000 Hz with an impedance tube, with the flow resistance being measured.

  10. Acoustic Absorption in Porous Materials

    NASA Technical Reports Server (NTRS)

    Kuczmarski, Maria A.; Johnston, James C.

    2011-01-01

    An understanding of both the areas of materials science and acoustics is necessary to successfully develop materials for acoustic absorption applications. This paper presents the basic knowledge and approaches for determining the acoustic performance of porous materials in a manner that will help materials researchers new to this area gain the understanding and skills necessary to make meaningful contributions to this field of study. Beginning with the basics and making as few assumptions as possible, this paper reviews relevant topics in the acoustic performance of porous materials, which are often used to make acoustic bulk absorbers, moving from the physics of sound wave interactions with porous materials to measurement techniques for flow resistivity, characteristic impedance, and wavenumber.

  11. HI Absorption in Merger Remnants

    NASA Technical Reports Server (NTRS)

    Teng, Stacy H.; Veileux, Sylvain; Baker, Andrew J.

    2012-01-01

    It has been proposed that ultraluminous infrared galaxies (ULIRGs) pass through a luminous starburst phase, followed by a dust-enshrouded AGN phase, and finally evolve into optically bright "naked" quasars once they shed their gas/dust reservoirs through powerful wind events. We present the results of our recent 21- cm HI survey of 21 merger remnants with the Green Bank Telescope. These remnants were selected from the QUEST (Quasar/ULIRG Evolution Study) sample of ULIRGs and PG quasars; our targets are all bolometrically dominated by AGN and sample all phases of the proposed ULIRG -> IR-excess quasar -> optical quasar sequence. We explore whether there is an evolutionary connection between ULIRGs and quasars by looking for the occurrence of HI absorption tracing neutral gas outflows; our results will allow us to identify where along the sequence the majority of a merger's gas reservoir is expelled.

  12. Backscatter absorption gas imaging system

    DOEpatents

    McRae, Jr., Thomas G.

    1985-01-01

    A video imaging system for detecting hazardous gas leaks. Visual displays of invisible gas clouds are produced by radiation augmentation of the field of view of an imaging device by radiation corresponding to an absorption line of the gas to be detected. The field of view of an imager is irradiated by a laser. The imager receives both backscattered laser light and background radiation. When a detectable gas is present, the backscattered laser light is highly attenuated, producing a region of contrast or shadow on the image. A flying spot imaging system is utilized to synchronously irradiate and scan the area to lower laser power requirements. The imager signal is processed to produce a video display.

  13. Backscatter absorption gas imaging system

    DOEpatents

    McRae, T.G. Jr.

    A video imaging system for detecting hazardous gas leaks. Visual displays of invisible gas clouds are produced by radiation augmentation of the field of view of an imaging device by radiation corresponding to an absorption line of the gas to be detected. The field of view of an imager is irradiated by a laser. The imager receives both backscattered laser light and background radiation. When a detectable gas is present, the backscattered laser light is highly attenuated, producing a region of contrast or shadow on the image. A flying spot imaging system is utilized to synchronously irradiate and scan the area to lower laser power requirements. The imager signal is processed to produce a video display.

  14. Examples of Sentinel-2A Mission Exploitation Results

    NASA Astrophysics Data System (ADS)

    Koetz, Benjamin; Hoersch, Bianca; Gascon, Ferran; Desnos, Yves-Louis; Seifert, Frank Martin; Paganini, Marc; Ramoino, Fabrizio; Arino, Olivier

    2017-04-01

    The Sentinel-2 Copernicus mission will bring significant breakthrough in the exploitation of space borne optical data. Sentinel-2 time series will transform land cover, agriculture, forestry, in-land water and costal EO applications from mapping to monitoring, from snapshot to time series data analysis, from image-based to pixel-based processing. The 5-days temporal revisiting of the Sentinel-2 satellites, when both units will be operated together, will usher us in a new era for time series analysis at high spatial resolutions (HR) of 10-20 meters. The monitoring of seasonal variations and processes in phenology and hydrology are examples of the many R&D areas to be studied. The mission's large swath and systematic acquisitions will further support unprecedented coverage at the national scale addressing information requirements of national to regional policies. Within ESA programs, such as the Data User Element (DUE), Scientific Exploitation of Operational Missions (SEOM) and Climate Change Initiative (CCI), several R&D activities are preparing the exploitation of the Sentinel-2 mission towards reliable measurements and monitoring of e.g. Essential Climate Variables and indicators for the Sustainable Development Goals. Early Sentinel-2 results will be presented related to a range of applications and scientific domains such as agricultural monitoring at national scale (DUE Sen2Agri), wetland extent and condition over African Ramsar sites (DUE GlobWetland-Africa), land cover mapping for climate change (CCI Land Cover), national land monitoring (Cadaster-Env), forest degradation (DUE ForMoSa), urban mapping (DUE EO4Urban), in-land water quality (DUE SPONGE), map of Mediterranean aquaculture (DUE SMART) and coral reef habitat mapping (SEOM S2-4Sci Coral). The above-mentioned activities are only a few examples from the very active international land imaging community building on the long-term Landsat and Spot heritage and knowledge.

  15. 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

  16. FSH: fast spaced seed hashing exploiting adjacent hashes.

    PubMed

    Girotto, Samuele; Comin, Matteo; Pizzi, Cinzia

    2018-01-01

    Patterns with wildcards in specified positions, namely spaced seeds , are increasingly used instead of k -mers in many bioinformatics applications that require indexing, querying and rapid similarity search, as they can provide better sensitivity. Many of these applications require to compute the hashing of each position in the input sequences with respect to the given spaced seed, or to multiple spaced seeds. While the hashing of k -mers can be rapidly computed by exploiting the large overlap between consecutive k -mers, spaced seeds hashing is usually computed from scratch for each position in the input sequence, thus resulting in slower processing. The method proposed in this paper, fast spaced-seed hashing (FSH), exploits the similarity of the hash values of spaced seeds computed at adjacent positions in the input sequence. In our experiments we compute the hash for each positions of metagenomics reads from several datasets, with respect to different spaced seeds. We also propose a generalized version of the algorithm for the simultaneous computation of multiple spaced seeds hashing. In the experiments, our algorithm can compute the hashing values of spaced seeds with a speedup, with respect to the traditional approach, between 1.6[Formula: see text] to 5.3[Formula: see text], depending on the structure of the spaced seed. Spaced seed hashing is a routine task for several bioinformatics application. FSH allows to perform this task efficiently and raise the question of whether other hashing can be exploited to further improve the speed up. This has the potential of major impact in the field, making spaced seed applications not only accurate, but also faster and more efficient. The software FSH is freely available for academic use at: https://bitbucket.org/samu661/fsh/overview.

  17. Using choice architecture to exploit a university Distinct Urban Mine.

    PubMed

    Pierron, Xavier; Williams, Ian D; Shaw, Peter J; Cleaver, Victoria

    2017-10-01

    There are widespread concerns regarding the potential future scarcity of ferrous and non-ferrous materials. However, there are already potentially rich reserves of secondary materials via high ownership of Electrical and Electronic Equipment (EEE) in economically-developed nations. Young people are particularly high consumers of EEE, thus university students and campuses may present an opportunity to harness this potential. University Distinct Urban Mines (DUM) may be used to exemplify how potential reserves of secondary metals may be exploited, and could contribute to the transition from a linear to a circular economy. This study aimed to evaluate small household appliances (SHA) DUM from a UK university, with the objectives to identify and quantify student households' SHA ownership, WEEE recycling, stockpiling and discarding habits amongst student households, assess and evaluate the monetary potential of SHA DUM at UK level, and propose methods to exploit DUM for universities in the UK. To this purpose, a quantitative survey was undertaken to measure students' ownership and discarding behaviour with respect to SHA. The amounts of ferrous and non-ferrous materials were then estimated and converted to monetary values from secondary materials market data to appraise the SHA DUM overall value. Thirty-five per cent of SHA are discarded in the general refuse. Broken personal care appliances (PCA) tend to be discarded due to hygiene and small size factors. When in working order, SHA tend to be equally reused, recycled or stockpiled. We conclude that a total of 189 tonnes of ferrous and non-ferrous materials were available via discarding or being stockpiled at the University of Southampton. Extrapolated to UK higher education level, discarded and stockpiled SHA represent a potential worth ∼USD 11 million. To initiate DUM exploitation within Higher Education campuses, we suggest improving users' choice architecture by providing collection methods specific to broken SHA

  18. 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.

  19. Global Assessment of Exploitable Surface Reservoir Storage under Climate Change

    NASA Astrophysics Data System (ADS)

    Liu, L.; Parkinson, S.; Gidden, M.; Byers, E.; Satoh, Y.; Riahi, K.

    2016-12-01

    Surface water reservoirs provide us with reliable water supply systems, hydropower generation, flood control, and recreation services. Reliable reservoirs can be robust measures for water security and can help smooth out challenging seasonal variability of river flows. Yet, reservoirs also cause flow fragmentation in rivers and can lead to flooding of upstream areas, thereby displacing existing land-uses and ecosystems. The anticipated population growth, land use and climate change in many regions globally suggest a critical need to assess the potential for appropriate reservoir capacity that can balance rising demands with long-term water security. In this research, we assessed exploitable reservoir potential under climate change and human development constraints by deriving storage-yield relationships for 235 river basins globally. The storage-yield relationships map the amount of storage capacity required to meet a given water demand based on a 30-year inflow sequence. Runoff data is simulated with an ensemble of Global Hydrological Models (GHMs) for each of five bias-corrected general circulation models (GCMs) under four climate change pathways. These data are used to define future 30-year inflows in each river basin for time period between 2010 and 2080. The calculated capacity is then combined with geographical information of environmental and human development exclusion zones to further limit the storage capacity expansion potential in each basin. We investigated the reliability of reservoir potentials across different climate change scenarios and Shared Socioeconomic Pathways (SSPs) to identify river basins where reservoir expansion will be particularly challenging. Preliminary results suggest large disparities in reservoir potential across basins: some basins have already approached exploitable reserves, while some others display abundant potential. Exclusions zones pose significant impact on the amount of actual exploitable storage and firm yields

  20. Biosonar navigation above water II: exploiting mirror images.

    PubMed

    Genzel, Daria; Hoffmann, Susanne; Prosch, Selina; Firzlaff, Uwe; Wiegrebe, Lutz

    2015-02-15

    As in vision, acoustic signals can be reflected by a smooth surface creating an acoustic mirror image. Water bodies represent the only naturally occurring horizontal and acoustically smooth surfaces. Echolocating bats flying over smooth water bodies encounter echo-acoustic mirror images of objects above the surface. Here, we combined an electrophysiological approach with a behavioral experimental paradigm to investigate whether bats can exploit echo-acoustic mirror images for navigation and how these mirrorlike echo-acoustic cues are encoded in their auditory cortex. In an obstacle-avoidance task where the obstacles could only be detected via their echo-acoustic mirror images, most bats spontaneously exploited these cues for navigation. Sonar ensonifications along the bats' flight path revealed conspicuous changes of the reflection patterns with slightly increased target strengths at relatively long echo delays corresponding to the longer acoustic paths from the mirrored obstacles. Recordings of cortical spatiotemporal response maps (STRMs) describe the tuning of a unit across the dimensions of elevation and time. The majority of cortical single and multiunits showed a special spatiotemporal pattern of excitatory areas in their STRM indicating a preference for echoes with (relative to the setup dimensions) long delays and, interestingly, from low elevations. This neural preference could effectively encode a reflection pattern as it would be perceived by an echolocating bat detecting an object mirrored from below. The current study provides both behavioral and neurophysiological evidence that echo-acoustic mirror images can be exploited by bats for obstacle avoidance. This capability effectively supports echo-acoustic navigation in highly cluttered natural habitats. Copyright © 2015 the American Physiological Society.

  1. Separating large microscale particles by exploiting charge differences with dielectrophoresis.

    PubMed

    Polniak, Danielle V; Goodrich, Eric; Hill, Nicole; Lapizco-Encinas, Blanca H

    2018-04-13

    Dielectrophoresis (DEP), the migration of particles due to polarization effects under the influence of a nonuniform electric field, was employed for characterizing the behavior and achieving the separation of larger (diameter >5 μm) microparticles by exploiting differences in electrical charge. Usually, electrophoresis (EP) is the method of choice for separating particles based on differences in electrical charge; however, larger particles, which have low electrophoretic mobilities, cannot be easily separated with EP-based techniques. This study presents an alternative for the characterization, assessment, and separation of larger microparticles, where charge differences are exploited with DEP instead of EP. Polystyrene microparticles with sizes varying from 5 to 10 μm were characterized employing microdevices for insulator-based dielectrophoresis (iDEP). Particles within an iDEP microchannel were exposed simultaneously to DEP, EP, and electroosmotic (EO) forces. The electrokinetic behavior of four distinct types of microparticles was carefully characterized by means of velocimetry and dielectrophoretic capture assessments. As a final step, a dielectropherogram separation of two distinct types of 10 μm particles was devised by first characterizing the particles and then performing the separation. The two types of 10 μm particles were eluted from the iDEP device as two separate peaks of enriched particles in less than 80 s. It was demonstrated that particles with the same size, shape, surface functionalization, and made from the same bulk material can be separated with iDEP by exploiting slight differences in the magnitude of particle charge. The results from this study open the possibility for iDEP to be used as a technique for the assessment and separation of biological cells that have very similar characteristics (shape, size, similar make-up), but slight variance in surface electrical charge. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Construct exploit constraint in crash analysis by bypassing canary

    NASA Astrophysics Data System (ADS)

    Huang, Ning; Huang, Shuguang; Huang, Hui; Chang, Chao

    2017-08-01

    Selective symbolic execution is a common program testing technology. Developed on the basis of it, some crash analysis systems are often used to test the fragility of the program by constructing exploit constraints, such as CRAX. From the study of crash analysis based on symbolic execution, this paper find that this technology cannot bypass the canary stack protection mechanisms. This paper makes the improvement uses the API hook in Linux. Experimental results show that the use of API hook can effectively solve the problem that crash analysis cannot bypass the canary protection.

  4. 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.

  5. The largest renewable, easily exploitable, and economically sustainable energy resource

    NASA Astrophysics Data System (ADS)

    Abbate, Giancarlo; Saraceno, Eugenio

    2018-02-01

    Sun, the ultimate energy resource of our planet, transfers energy to the Earth at an average power of 23,000 TW. Earth surface can be regarded as a huge panel transforming solar energy into a more convenient mechanical form, the wind. Since millennia wind is recognized as an exploitable form of energy and it is common knowledge that the higher you go, the stronger the winds flow. To go high is difficult; however Bill Gates cites high wind among possible energy miracles in the near future. Public awareness of this possible miracle is still missing, but today's technology is ready for it.

  6. Synergy in spreading processes: from exploitative to explorative foraging strategies.

    PubMed

    Pérez-Reche, Francisco J; Ludlam, Jonathan J; Taraskin, Sergei N; Gilligan, Christopher A

    2011-05-27

    An epidemiological model which incorporates synergistic effects that allow the infectivity and/or susceptibility of hosts to be dependent on the number of infected neighbors is proposed. Constructive synergy induces an exploitative behavior which results in a rapid invasion that infects a large number of hosts. Interfering synergy leads to a slower and sparser explorative foraging strategy that traverses larger distances by infecting fewer hosts. The model can be mapped to a dynamical bond percolation with spatial correlations that affect the mechanism of spread but do not influence the critical behavior of epidemics. © 2011 American Physical Society

  7. Tailoring the Nanoporous Architecture of Hydrogels to Exploit Entropic Trapping

    NASA Astrophysics Data System (ADS)

    Shi, Nan; Ugaz, Victor M.

    2010-09-01

    Macromolecules embedded in a nanoporous matrix display anomalous transport behavior in the entropic trapping regime. But these phenomena have not been widely explored in hydrogel matrices because it has not been clear how to link them to the underlying heterogeneous nanopore morphology. Here we introduce a theoretical model that establishes this connection and describe microchip DNA electrophoresis experiments that demonstrate how entropic trapping effects can be exploited to yield a trend of increasing resolving power with DNA size (the opposite of what is conventionally observed).

  8. 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.

  9. Exploiting vibrational resonance in weak-signal detection.

    PubMed

    Ren, Yuhao; Pan, Yan; Duan, Fabing; Chapeau-Blondeau, François; Abbott, Derek

    2017-08-01

    In this paper, we investigate the first exploitation of the vibrational resonance (VR) effect to detect weak signals in the presence of strong background noise. By injecting a series of sinusoidal interference signals of the same amplitude but with different frequencies into a generalized correlation detector, we show that the detection probability can be maximized at an appropriate interference amplitude. Based on a dual-Dirac probability density model, we compare the VR method with the stochastic resonance approach via adding dichotomous noise. The compared results indicate that the VR method can achieve a higher detection probability for a wider variety of noise distributions.

  10. Exploiting vibrational resonance in weak-signal detection

    NASA Astrophysics Data System (ADS)

    Ren, Yuhao; Pan, Yan; Duan, Fabing; Chapeau-Blondeau, François; Abbott, Derek

    2017-08-01

    In this paper, we investigate the first exploitation of the vibrational resonance (VR) effect to detect weak signals in the presence of strong background noise. By injecting a series of sinusoidal interference signals of the same amplitude but with different frequencies into a generalized correlation detector, we show that the detection probability can be maximized at an appropriate interference amplitude. Based on a dual-Dirac probability density model, we compare the VR method with the stochastic resonance approach via adding dichotomous noise. The compared results indicate that the VR method can achieve a higher detection probability for a wider variety of noise distributions.

  11. 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

  12. 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.

  13. A benchmarking method to measure dietary absorption efficiency of chemicals by fish.

    PubMed

    Xiao, Ruiyang; Adolfsson-Erici, Margaretha; Åkerman, Gun; McLachlan, Michael S; MacLeod, Matthew

    2013-12-01

    Understanding the dietary absorption efficiency of chemicals in the gastrointestinal tract of fish is important from both a scientific and a regulatory point of view. However, reported fish absorption efficiencies for well-studied chemicals are highly variable. In the present study, the authors developed and exploited an internal chemical benchmarking method that has the potential to reduce uncertainty and variability and, thus, to improve the precision of measurements of fish absorption efficiency. The authors applied the benchmarking method to measure the gross absorption efficiency for 15 chemicals with a wide range of physicochemical properties and structures. They selected 2,2',5,6'-tetrachlorobiphenyl (PCB53) and decabromodiphenyl ethane as absorbable and nonabsorbable benchmarks, respectively. Quantities of chemicals determined in fish were benchmarked to the fraction of PCB53 recovered in fish, and quantities of chemicals determined in feces were benchmarked to the fraction of decabromodiphenyl ethane recovered in feces. The performance of the benchmarking procedure was evaluated based on the recovery of the test chemicals and precision of absorption efficiency from repeated tests. Benchmarking did not improve the precision of the measurements; after benchmarking, however, the median recovery for 15 chemicals was 106%, and variability of recoveries was reduced compared with before benchmarking, suggesting that benchmarking could account for incomplete extraction of chemical in fish and incomplete collection of feces from different tests. © 2013 SETAC.

  14. Seismic signatures of carbonate caves affected by near-surface absorptions

    NASA Astrophysics Data System (ADS)

    Rao, Ying; Wang, Yanghua

    2015-12-01

    The near-surface absorption within a low-velocity zone generally has an exponential attenuation effect on seismic waves. But how does this absorption affect seismic signatures of karstic caves in deep carbonate reservoirs? Seismic simulation and analysis reveals that, although this near-surface absorption attenuates the wave energy of a continuous reflection, it does not alter the basic kinematic shape of bead-string reflections, a special seismic characteristic associated with carbonate caves in the Tarim Basin, China. Therefore, the bead-strings in seismic profiles can be utilized, with a great certainty, for interpreting the existence of caves within the deep carbonate reservoirs and for evaluating their pore spaces. Nevertheless, the difference between the central frequency and the peak frequency is increased along with the increment in the absorption. While the wave energy of bead-string reflections remains strong, due to the interference of seismic multiples generated by big impedance contrast between the infill materials of a cave and the surrounding carbonate rocks, the central frequency is shifted linearly with respect to the near-surface absorption. These two features can be exploited simultaneously, for a stable attenuation analysis of field seismic data.

  15. Vitamin B12 absorption from eggs.

    PubMed

    Doscherholmen, A; McMahon, J; Ripley, D

    1975-09-01

    The assimilation of 57Co B12 from in vivo labeled eggs was much inferior to that of a comparable amount of crystalline 57Co B12. Furthermore, the absorption varied with the form in which the eggs were served. Judged by the urinary excretion test and the plasma absorption of radioactivity the average absorption from boiled and fried eggs was more than twice that from scrambled whole eggs, but less than half that absorbed from crystalline 57Co B12.

  16. On pulsating cosmic /radio/ noise absorption

    NASA Technical Reports Server (NTRS)

    Dangelo, N.

    1981-01-01

    It has been proposed that some absorption events measured on riometers are actually due to backscatter of cosmic radio noise by E-region plasma waves (D'Angelo, 1976, 1978; D'Angelo and Mehta, 1980). Assuming that DC or nearly DC absorption is a viable process, it is shown that it may also be operative in producing pulsations in cosmic noise absorption on riometers, with periods ranging from a few seconds to several minutes.

  17. Absorption Coefficient of Alkaline Earth Halides.

    DTIC Science & Technology

    1980-04-01

    not observed at low energy level , are developed at high power levels . No matter how low the absorption is. the effect is objectionable at high-energy... levels . As a natural consequence, the magnitude of the absorption coefficient is the key parameter in selecting laser window materials. Over the past...Presence of impurities can complicate the exponential tail. particularly at low absorption levels . The impurities may enter 12 the lattice singly or

  18. NARROW LINE ABSORPTION IN CACO3.

    DTIC Science & Technology

    CARBONATES), (*CALCIUM COMPOUNDS, (*ABSORPTION SPECTRA, CALCITE), (*CALCITE, RADIATION EFFECTS), ELECTRON PARAMAGNETIC RESONANCE, SINGLE CRYSTALS , NEUTRONS, X RAYS, GAMMA RAYS, IONS, CRYSTAL DEFECTS, PARAMAGNETIC RESONANCE.

  19. Sampling limits for electron tomography with sparsity-exploiting reconstructions.

    PubMed

    Jiang, Yi; Padgett, Elliot; Hovden, Robert; Muller, David A

    2018-03-01

    Electron tomography (ET) has become a standard technique for 3D characterization of materials at the nano-scale. Traditional reconstruction algorithms such as weighted back projection suffer from disruptive artifacts with insufficient projections. Popularized by compressed sensing, sparsity-exploiting algorithms have been applied to experimental ET data and show promise for improving reconstruction quality or reducing the total beam dose applied to a specimen. Nevertheless, theoretical bounds for these methods have been less explored in the context of ET applications. Here, we perform numerical simulations to investigate performance of ℓ 1 -norm and total-variation (TV) minimization under various imaging conditions. From 36,100 different simulated structures, our results show specimens with more complex structures generally require more projections for exact reconstruction. However, once sufficient data is acquired, dividing the beam dose over more projections provides no improvements-analogous to the traditional dose-fraction theorem. Moreover, a limited tilt range of ±75° or less can result in distorting artifacts in sparsity-exploiting reconstructions. The influence of optimization parameters on reconstructions is also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. 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.

  1. The HACMS program: using formal methods to eliminate exploitable bugs

    PubMed Central

    Launchbury, John; Richards, Raymond

    2017-01-01

    For decades, formal methods have offered the promise of verified software that does not have exploitable bugs. Until recently, however, it has not been possible to verify software of sufficient complexity to be useful. Recently, that situation has changed. SeL4 is an open-source operating system microkernel efficient enough to be used in a wide range of practical applications. Its designers proved it to be fully functionally correct, ensuring the absence of buffer overflows, null pointer exceptions, use-after-free errors, etc., and guaranteeing integrity and confidentiality. The CompCert Verifying C Compiler maps source C programs to provably equivalent assembly language, ensuring the absence of exploitable bugs in the compiler. A number of factors have enabled this revolution, including faster processors, increased automation, more extensive infrastructure, specialized logics and the decision to co-develop code and correctness proofs rather than verify existing artefacts. In this paper, we explore the promise and limitations of current formal-methods techniques. We discuss these issues in the context of DARPA’s HACMS program, which had as its goal the creation of high-assurance software for vehicles, including quadcopters, helicopters and automobiles. This article is part of the themed issue ‘Verified trustworthy software systems’. PMID:28871050

  2. Exploiting the Dynamics of Soft Materials for Machine Learning

    PubMed Central

    Hauser, Helmut; Li, Tao; Pfeifer, Rolf

    2018-01-01

    Abstract Soft materials are increasingly utilized for various purposes in many engineering applications. These materials have been shown to perform a number of functions that were previously difficult to implement using rigid materials. Here, we argue that the diverse dynamics generated by actuating soft materials can be effectively used for machine learning purposes. This is demonstrated using a soft silicone arm through a technique of multiplexing, which enables the rich transient dynamics of the soft materials to be fully exploited as a computational resource. The computational performance of the soft silicone arm is examined through two standard benchmark tasks. Results show that the soft arm compares well to or even outperforms conventional machine learning techniques under multiple conditions. We then demonstrate that this system can be used for the sensory time series prediction problem for the soft arm itself, which suggests its immediate applicability to a real-world machine learning problem. Our approach, on the one hand, represents a radical departure from traditional computational methods, whereas on the other hand, it fits nicely into a more general perspective of computation by way of exploiting the properties of physical materials in the real world. PMID:29708857

  3. Exploiting the Dynamics of Soft Materials for Machine Learning.

    PubMed

    Nakajima, Kohei; Hauser, Helmut; Li, Tao; Pfeifer, Rolf

    2018-06-01

    Soft materials are increasingly utilized for various purposes in many engineering applications. These materials have been shown to perform a number of functions that were previously difficult to implement using rigid materials. Here, we argue that the diverse dynamics generated by actuating soft materials can be effectively used for machine learning purposes. This is demonstrated using a soft silicone arm through a technique of multiplexing, which enables the rich transient dynamics of the soft materials to be fully exploited as a computational resource. The computational performance of the soft silicone arm is examined through two standard benchmark tasks. Results show that the soft arm compares well to or even outperforms conventional machine learning techniques under multiple conditions. We then demonstrate that this system can be used for the sensory time series prediction problem for the soft arm itself, which suggests its immediate applicability to a real-world machine learning problem. Our approach, on the one hand, represents a radical departure from traditional computational methods, whereas on the other hand, it fits nicely into a more general perspective of computation by way of exploiting the properties of physical materials in the real world.

  4. The Exploration-Exploitation Dilemma: A Multidisciplinary Framework

    PubMed Central

    Berger-Tal, Oded; Meron, Ehud; Saltz, David

    2014-01-01

    The trade-off between the need to obtain new knowledge and the need to use that knowledge to improve performance is one of the most basic trade-offs in nature, and optimal performance usually requires some balance between exploratory and exploitative behaviors. Researchers in many disciplines have been searching for the optimal solution to this dilemma. Here we present a novel model in which the exploration strategy itself is dynamic and varies with time in order to optimize a definite goal, such as the acquisition of energy, money, or prestige. Our model produced four very distinct phases: Knowledge establishment, Knowledge accumulation, Knowledge maintenance, and Knowledge exploitation, giving rise to a multidisciplinary framework that applies equally to humans, animals, and organizations. The framework can be used to explain a multitude of phenomena in various disciplines, such as the movement of animals in novel landscapes, the most efficient resource allocation for a start-up company, or the effects of old age on knowledge acquisition in humans. PMID:24756026

  5. 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).

  6. Exploiting similarity in turbulent shear flows for turbulence modeling

    NASA Technical Reports Server (NTRS)

    Robinson, David F.; Harris, Julius E.; Hassan, H. A.

    1992-01-01

    It is well known that current k-epsilon models cannot predict the flow over a flat plate and its wake. In an effort to address this issue and other issues associated with turbulence closure, a new approach for turbulence modeling is proposed which exploits similarities in the flow field. Thus, if we consider the flow over a flat plate and its wake, then in addition to taking advantage of the log-law region, we can exploit the fact that the flow becomes self-similar in the far wake. This latter behavior makes it possible to cast the governing equations as a set of total differential equations. Solutions of this set and comparison with measured shear stress and velocity profiles yields the desired set of model constants. Such a set is, in general, different from other sets of model constants. The rational for such an approach is that if we can correctly model the flow over a flat plate and its far wake, then we can have a better chance of predicting the behavior in between. It is to be noted that the approach does not appeal, in any way, to the decay of homogeneous turbulence. This is because the asymptotic behavior of the flow under consideration is not representative of the decay of homogeneous turbulence.

  7. Exploiting similarity in turbulent shear flows for turbulence modeling

    NASA Astrophysics Data System (ADS)

    Robinson, David F.; Harris, Julius E.; Hassan, H. A.

    1992-12-01

    It is well known that current k-epsilon models cannot predict the flow over a flat plate and its wake. In an effort to address this issue and other issues associated with turbulence closure, a new approach for turbulence modeling is proposed which exploits similarities in the flow field. Thus, if we consider the flow over a flat plate and its wake, then in addition to taking advantage of the log-law region, we can exploit the fact that the flow becomes self-similar in the far wake. This latter behavior makes it possible to cast the governing equations as a set of total differential equations. Solutions of this set and comparison with measured shear stress and velocity profiles yields the desired set of model constants. Such a set is, in general, different from other sets of model constants. The rational for such an approach is that if we can correctly model the flow over a flat plate and its far wake, then we can have a better chance of predicting the behavior in between. It is to be noted that the approach does not appeal, in any way, to the decay of homogeneous turbulence. This is because the asymptotic behavior of the flow under consideration is not representative of the decay of homogeneous turbulence.

  8. Activity-based exploitation of Full Motion Video (FMV)

    NASA Astrophysics Data System (ADS)

    Kant, Shashi

    2012-06-01

    Video has been a game-changer in how US forces are able to find, track and defeat its adversaries. With millions of minutes of video being generated from an increasing number of sensor platforms, the DOD has stated that the rapid increase in video is overwhelming their analysts. The manpower required to view and garner useable information from the flood of video is unaffordable, especially in light of current fiscal restraints. "Search" within full-motion video has traditionally relied on human tagging of content, and video metadata, to provision filtering and locate segments of interest, in the context of analyst query. Our approach utilizes a novel machine-vision based approach to index FMV, using object recognition & tracking, events and activities detection. This approach enables FMV exploitation in real-time, as well as a forensic look-back within archives. This approach can help get the most information out of video sensor collection, help focus the attention of overburdened analysts form connections in activity over time and conserve national fiscal resources in exploiting FMV.

  9. 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.

  10. 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

  11. Exploitation of induced 2n-gametes for plant breeding.

    PubMed

    Younis, Adnan; Hwang, Yoon-Jung; Lim, Ki-Byung

    2014-02-01

    Unreduced gamete formation derived via abnormal meiotic cell division is an important approach to polyploidy breeding. This process is considered the main driving force in spontaneous polyploids formation in nature, but the potential application of these gametes to plant breeding has not been fully exploited. An effective mechanism for their artificial induction is needed to attain greater genetic variation and enable efficient use of unreduced gametes in breeding programs. Different approaches have been employed for 2n-pollen production including interspecific hybridization, manipulation of environmental factors and treatment with nitrous oxide, trifluralin, colchicine, oryzalin and other chemicals. These chemicals can act as a stimulus to produce viable 2n pollen; however, their exact mode of action, optimum concentration and developmental stages are still not known. Identification of efficient methods of inducing 2n-gamete formation will help increase pollen germination of sterile interspecific hybrids for inter-genomic recombination and introgression breeding to develop new polyploid cultivars and increase heterozygosity among plant populations. Additionally, the application of genomic tools and identification and isolation of genes and mechanisms involved in the induction of 2n-gamete will enable increased exploitation in different plant species, which will open new avenues for plant breeding.

  12. Exploiting Software Tool Towards Easier Use And Higher Efficiency

    NASA Astrophysics Data System (ADS)

    Lin, G. H.; Su, J. T.; Deng, Y. Y.

    2006-08-01

    In developing countries, using data based on instrument made by themselves in maximum extent is very important. It is not only related to maximizing science returns upon prophase investment -- deep accumulations in every aspects but also science output. Based on the idea, we are exploiting a software (called THDP: Tool of Huairou Data Processing). It is used for processing a series of issues, which is met necessary in processing data. This paper discusses its designed purpose, functions, method and specialities. The primary vehicle for general data interpretation is through various techniques of data visualization, techniques of interactive. In the software, we employed Object Oriented approach. It is appropriate to the vehicle. it is imperative that the approach provide not only function, but do so in as convenient a fashion as possible. As result of the software exploiting, it is not only easier to learn data processing for beginner and more convenienter to need further improvement for senior but also increase greatly efficiency in every phrases include analyse, parameter adjusting, result display. Under frame of virtual observatory, for developing countries, we should study more and newer related technologies, which can advance ability and efficiency in science research, like the software we are developing

  13. A Novel Passive Tracking Scheme Exploiting Geometric and Intercept Theorems

    PubMed Central

    Zhou, Biao; Sun, Chao; Ahn, Deockhyeon; Kim, Youngok

    2018-01-01

    Passive tracking aims to track targets without assistant devices, that is, device-free targets. Passive tracking based on Radio Frequency (RF) Tomography in wireless sensor networks has recently been addressed as an emerging field. The passive tracking scheme using geometric theorems (GTs) is one of the most popular RF Tomography schemes, because the GT-based method can effectively mitigate the demand for a high density of wireless nodes. In the GT-based tracking scheme, the tracking scenario is considered as a two-dimensional geometric topology and then geometric theorems are applied to estimate crossing points (CPs) of the device-free target on line-of-sight links (LOSLs), which reveal the target’s trajectory information in a discrete form. In this paper, we review existing GT-based tracking schemes, and then propose a novel passive tracking scheme by exploiting the Intercept Theorem (IT). To create an IT-based CP estimation scheme available in the noisy non-parallel LOSL situation, we develop the equal-ratio traverse (ERT) method. Finally, we analyze properties of three GT-based tracking algorithms and the performance of these schemes is evaluated experimentally under various trajectories, node densities, and noisy topologies. Analysis of experimental results shows that tracking schemes exploiting geometric theorems can achieve remarkable positioning accuracy even under rather a low density of wireless nodes. Moreover, the proposed IT scheme can provide generally finer tracking accuracy under even lower node density and noisier topologies, in comparison to other schemes. PMID:29562621

  14. An automated data exploitation system for airborne sensors

    NASA Astrophysics Data System (ADS)

    Chen, Hai-Wen; McGurr, Mike

    2014-06-01

    Advanced wide area persistent surveillance (WAPS) sensor systems on manned or unmanned airborne vehicles are essential for wide-area urban security monitoring in order to protect our people and our warfighter from terrorist attacks. Currently, human (imagery) analysts process huge data collections from full motion video (FMV) for data exploitation and analysis (real-time and forensic), providing slow and inaccurate results. An Automated Data Exploitation System (ADES) is urgently needed. In this paper, we present a recently developed ADES for airborne vehicles under heavy urban background clutter conditions. This system includes four processes: (1) fast image registration, stabilization, and mosaicking; (2) advanced non-linear morphological moving target detection; (3) robust multiple target (vehicles, dismounts, and human) tracking (up to 100 target tracks); and (4) moving or static target/object recognition (super-resolution). Test results with real FMV data indicate that our ADES can reliably detect, track, and recognize multiple vehicles under heavy urban background clutters. Furthermore, our example shows that ADES as a baseline platform can provide capability for vehicle abnormal behavior detection to help imagery analysts quickly trace down potential threats and crimes.

  15. 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

  16. Frontal Theta Reflects Uncertainty and Unexpectedness during Exploration and Exploitation

    PubMed Central

    Figueroa, Christina M.; Cohen, Michael X; Frank, Michael J.

    2012-01-01

    In order to understand the exploitation/exploration trade-off in reinforcement learning, previous theoretical and empirical accounts have suggested that increased uncertainty may precede the decision to explore an alternative option. To date, the neural mechanisms that support the strategic application of uncertainty-driven exploration remain underspecified. In this study, electroencephalography (EEG) was used to assess trial-to-trial dynamics relevant to exploration and exploitation. Theta-band activities over middle and lateral frontal areas have previously been implicated in EEG studies of reinforcement learning and strategic control. It was hypothesized that these areas may interact during top-down strategic behavioral control involved in exploratory choices. Here, we used a dynamic reward–learning task and an associated mathematical model that predicted individual response times. This reinforcement-learning model generated value-based prediction errors and trial-by-trial estimates of exploration as a function of uncertainty. Mid-frontal theta power correlated with unsigned prediction error, although negative prediction errors had greater power overall. Trial-to-trial variations in response-locked frontal theta were linearly related to relative uncertainty and were larger in individuals who used uncertainty to guide exploration. This finding suggests that theta-band activities reflect prefrontal-directed strategic control during exploratory choices. PMID:22120491

  17. JPEG2000-coded image error concealment exploiting convex sets projections.

    PubMed

    Atzori, Luigi; Ginesu, Giaime; Raccis, Alessio

    2005-04-01

    Transmission errors in JPEG2000 can be grouped into three main classes, depending on the affected area: LL, high frequencies at the lower decomposition levels, and high frequencies at the higher decomposition levels. The first type of errors are the most annoying but can be concealed exploiting the signal spatial correlation like in a number of techniques proposed in the past; the second are less annoying but more difficult to address; the latter are often imperceptible. In this paper, we address the problem of concealing the second class or errors when high bit-planes are damaged by proposing a new approach based on the theory of projections onto convex sets. Accordingly, the error effects are masked by iteratively applying two procedures: low-pass (LP) filtering in the spatial domain and restoration of the uncorrupted wavelet coefficients in the transform domain. It has been observed that a uniform LP filtering brought to some undesired side effects that negatively compensated the advantages. This problem has been overcome by applying an adaptive solution, which exploits an edge map to choose the optimal filter mask size. Simulation results demonstrated the efficiency of the proposed approach.

  18. Self-report measure of financial exploitation of older adults.

    PubMed

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

    2010-12-01

    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. rasch item response theory and traditional validation approaches were used. Questionnaires were administered by 22 adult protective services investigators from 7 agencies in Illinois to 227 substantiated abuse clients. Analyses included tests for dimensionality, model fit, and additional construct validation. Results from the OAFEM were also compared with the substantiation decision of abuse and with investigators' assessments of FE using a staff report version. Hypotheses were generated to test hypothesized relationships. the OAFEM, including the original 79-, 54-, and 30-item measures, met stringent Rasch analysis fit and unidimensionality criteria and had high internal consistency and item reliability. The validation results were supportive, while leading to reconsideration of aspects of the hypothesized theoretical hierarchy. Thresholds were suggested to demonstrate levels of severity. the measure is now available to aid in the assessment of FE of older adults by both clinicians and researchers. Theoretical refinements developed using the empirically generated item hierarchy may help to improve assessment and intervention.

  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. The HACMS program: using formal methods to eliminate exploitable bugs.

    PubMed

    Fisher, Kathleen; Launchbury, John; Richards, Raymond

    2017-10-13

    For decades, formal methods have offered the promise of verified software that does not have exploitable bugs. Until recently, however, it has not been possible to verify software of sufficient complexity to be useful. Recently, that situation has changed. SeL4 is an open-source operating system microkernel efficient enough to be used in a wide range of practical applications. Its designers proved it to be fully functionally correct, ensuring the absence of buffer overflows, null pointer exceptions, use-after-free errors, etc., and guaranteeing integrity and confidentiality. The CompCert Verifying C Compiler maps source C programs to provably equivalent assembly language, ensuring the absence of exploitable bugs in the compiler. A number of factors have enabled this revolution, including faster processors, increased automation, more extensive infrastructure, specialized logics and the decision to co-develop code and correctness proofs rather than verify existing artefacts. In this paper, we explore the promise and limitations of current formal-methods techniques. We discuss these issues in the context of DARPA's HACMS program, which had as its goal the creation of high-assurance software for vehicles, including quadcopters, helicopters and automobiles.This article is part of the themed issue 'Verified trustworthy software systems'. © 2017 The Authors.

  1. The environmental impacts of foamed concrete production and exploitation

    NASA Astrophysics Data System (ADS)

    Namsone, E.; Korjakins, A.; Sahmenko, G.; Sinka, M.

    2017-10-01

    This paper presents a study focusing on the environmental impacts of foamed concrete production and exploitation. CO2 emissions are very important factor for describing durability and sustainability of any building material and its life cycle. The building sector is one of the largest energy-consuming sectors in the world. In this study CO2 emissions are evaluated with regard to three types of energy resources (gas, coal and eco-friendly fuel). The related savings on raw materials are up to 120 t of water per 1000 t of traditionally mixed foamed concrete and up to 350 t of sand per 1000 t of foamed concrete produced with intensive mixing technology. In addition, total reduction of CO2 emissions (up to 60 t per 1000 m3 of material) and total energy saving from introduction of foamed concrete production (depending on the type of fuel) were calculated. In order to analyze the conditions of exploitation, both thermal conductivity and thickness of wall was determined. All obtained and calculated results were compared to those of the commercially produced autoclaved aerated concrete.

  2. Exploiting GPUs in virtual machine for BioCloud.

    PubMed

    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.

  3. Exploiting the wavelet structure in compressed sensing MRI.

    PubMed

    Chen, Chen; Huang, Junzhou

    2014-12-01

    Sparsity has been widely utilized in magnetic resonance imaging (MRI) to reduce k-space sampling. According to structured sparsity theories, fewer measurements are required for tree sparse data than the data only with standard sparsity. Intuitively, more accurate image reconstruction can be achieved with the same number of measurements by exploiting the wavelet tree structure in MRI. A novel algorithm is proposed in this article to reconstruct MR images from undersampled k-space data. In contrast to conventional compressed sensing MRI (CS-MRI) that only relies on the sparsity of MR images in wavelet or gradient domain, we exploit the wavelet tree structure to improve CS-MRI. This tree-based CS-MRI problem is decomposed into three simpler subproblems then each of the subproblems can be efficiently solved by an iterative scheme. Simulations and in vivo experiments demonstrate the significant improvement of the proposed method compared to conventional CS-MRI algorithms, and the feasibleness on MR data compared to existing tree-based imaging algorithms. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. The Potential Socio-economic Impacts of Gas Hydrate Exploitation

    NASA Astrophysics Data System (ADS)

    Riley, David; Schaafsma, Marije; Marin-Moreno, Héctor; Minshull, Tim A.

    2017-04-01

    Gas hydrate has garnered significant interest as a possible clean fossil fuel resource, especially in countries with limited energy supplies. Whilst the sector is still in its infancy, there has been escalating development towards commercial production. To the best of our knowledge it appears that, despite its potential, existing analyses of the social and economic impacts of hydrate exploitation have been very limited. Before any viable commercial production commences, the potential impacts across society must be considered. It is likely that such impact assessments will become a legislative requirement for hydrate exploitation, similar to their requirement in conventional oil and gas projects. Social impact analysis should guide hydrate development to have the highest possible net benefits to the human and natural environment. Without active commercial hydrate operations, potential socio-economic impacts can only be inferred from other fossil fuel resource focused communities, including those directly or indirectly affected by the oil and gas industry either in the vicinity of the well or further afield. This review attempts to highlight potential impacts by synthesising current literature, focusing on social impacts at the extraction stage of operation, over time. Using a DPSIR (Driving forces; Pressures; States; Impacts; Responses) framework, we focus on impacts upon: health and wellbeing, land use and access, services and infrastructure, population, employment opportunities, income and lifestyles. Human populations directly or indirectly related with fossil fuel extraction activities often show boom and bust dynamics, and so any impacts may be finite or change temporally. Therefore potential impacts have to be reassessed throughout the lifetime of the exploitation. Our review shows there are a wide range of possible positive and negative socio-economic impacts from hydrate development. Exploitation can bring jobs and infrastructure to remote areas, although

  5. Fluid absorption solar energy receiver

    NASA Technical Reports Server (NTRS)

    Bair, Edward J.

    1993-01-01

    A conventional solar dynamic system transmits solar energy to the flowing fluid of a thermodynamic cycle through structures which contain the gas and thermal energy storage material. Such a heat transfer mechanism dictates that the structure operate at a higher temperature than the fluid. This investigation reports on a fluid absorption receiver where only a part of the solar energy is transmitted to the structure. The other part is absorbed directly by the fluid. By proportioning these two heat transfer paths the energy to the structure can preheat the fluid, while the energy absorbed directly by the fluid raises the fluid to its final working temperature. The surface temperatures need not exceed the output temperature of the fluid. This makes the output temperature of the gas the maximum temperature in the system. The gas can have local maximum temperatures higher than the output working temperature. However local high temperatures are quickly equilibrated, and since the gas does not emit radiation, local high temperatures do not result in a radiative heat loss. Thermal radiation, thermal conductivity, and heat exchange with the gas all help equilibrate the surface temperature.

  6. Exploiting ten years of MERIS data over Land Surfaces

    NASA Astrophysics Data System (ADS)

    Gobron, Nadine

    2012-07-01

    Envisat's Medium Resolution Imaging Spectrometer (MERIS) acquires multi-spectral imagery of the Earth in the optical domain over terrestrial surfaces since a decade at global scale. Characteristics of the instrument will be first summarized and then several achievements for terrestrial applications will be presented as scientists have used data or products for characterizing the state of the global system and its variability. The ESA- GlobCover which has developed a service capable of delivering land cover maps on the basis of 300m spectral reflectance measurements will be summarized (Bicheron et al, 2008; Arino et al, 2010). We will highlight recent research results for continental land cover mapping over South America using MERIS data from 2009 and 2010 (Hojas Gascon et al, 2012). The objective and originality of this work was to generate a new land cover using selected MERIS data instead of all available images and supplementary information from associated Level-2 product, i.e. FAPAR, provided at a reduced resolution of 1 km. As the actual two level-2 products provided by ESA correspond to geophysical products such as the FAPAR (Fraction of Synthetically Active Radiation) and the MERIS terrestrial chlorophyll index (MTCI). With this latter, phenology studies as this product is sensitive to canopy chlorophyll content, a vegetation property that is a useful proxy for the canopy physical and chemical alterations associated with phenological change. (Dash and Curran, 2004; Boyd et al, 2011). For exploiting the use of the MGVI, ESA-Joint Research Center (JRC) FAPAR project has been created for producing time-series of geophysical products and will be summarized (Gobron et al, 2006, 2010; Fusco et al, 2003). It uses through various examples such as assessing drought at regional scale (Rossi etl a, 2010) or monitoring the state and changes of land surfaces global scale (Gobron et al, 2012). As the FAPAR value constitutes a state variable in advanced Earth system models

  7. Sentinel-2 data exploitation with ESA's Sentinel-2 Toolbox

    NASA Astrophysics Data System (ADS)

    Gascon, Ferran; Ramoino, Fabrizzio; deanos, Yves-louis

    2017-04-01

    The Sentinel-2 Toolbox is a project kicked off by ESA in early 2014, under the umbrella of the ESA SEOM programme with the aim to provide a tool for visualizing, analysing, and processing the Sentinel-2 datasets. The toolbox is an extension of the SeNtinel Application Platform (SNAP), a project resulting from the effort of the developers of the Sentinel-1, Sentinel-2 and Sentinel-3 toolbox to provide a single common application framework suited for the mixed exploitation of SAR, high resolution optical and medium resolution optical datasets. All three development teams collaborate to drive the evolution of the common SNAP framework in a developer forum. In this triplet, the Sentinel-2 toolbox is dedicated to enhance SNAP support for high resolution optical imagery. It is a multi-mission toolbox, already providing support for Sentinel-2, RapidEye, Deimos, SPOT 1 to SPOT 5 datasets. In terms of processing algorithms, SNAP provides tools specific to the Sentinel-2 mission : • An atmospheric correction module, Sen2Cor, is integrated into the toolbox, and provides scene classification, atmospheric correction, cirrus detection and correction. The output L2A products can be opened seamlessly in the toolbox. • A multitemporal synthesis processor (L3) • A biophysical products processor (L2B) • A water processor • A deforestation detector • OTB tools integration • SNAP Engine for Cloud Exploitation along with a set of more generic tools for high resolution optical data exploitation. Together with the generic functionalities of SNAP this provides an ideal environment for designing multi-missions processing chains and producing value-added products from raw datasets. The use of SNAP is manifold and the desktop tools provides a rich application for interactive visualization, analysis and processing of data. But all tools available from SNAP can be accessed via command-line through the Graph Processing Framework (GPT), the kernel of the SNAP processing engine. This

  8. Shale Gas Exploration and Exploitation Induced Risks - SHEER

    NASA Astrophysics Data System (ADS)

    Capuano, Paolo; Orlecka-Sikora, Beata; Lasocki, Stanislaw; Cesca, Simone; Gunning, Andrew; jaroslawsky, Janusz; Garcia-Aristizabal, Alexander; Westwood, Rachel; Gasparini, Paolo

    2017-04-01

    Shale gas operations may affect the quality of air, water and landscapes; furthermore, it can induce seismic activity, with the possible impacts on the surrounding infrastructure. The SHEER project aims at setting up a probabilistic methodology to assess and mitigate the short and the long term environmental risks connected to the exploration and exploitation of shale gas. In particular we are investigating risks associated with groundwater contamination, air pollution and induced seismicity. A shale gas test site located in Poland (Wysin) has been monitored before, during and after the fracking operations with the aim of assessing environmental risks connected with groundwater contamination, air pollution and earthquakes induced by fracking and injection of waste water. The severity of each of these hazards depends strongly on the unexpected enhanced permeability pattern, which may develop as an unwanted by-product of the fracking processes and may become pathway for gas and fluid migration towards underground water reservoirs or the surface. The project is devoted to monitor and understand how far this enhanced permeability pattern develops both in space and time. The considered hazards may be at least partially inter-related as they all depend on this enhanced permeability pattern. Therefore they are being approached from a multi-hazard, multi parameter perspective. We expect to develop methodologies and procedures to track and model fracture evolution around shale gas exploitation sites and a robust statistically based, multi-parameter methodology to assess environmental impacts and risks across the operational lifecycle of shale gas. The developed methodologies are going to be applied and tested on a comprehensive database consisting of seismicity, changes of the quality of ground-waters and air, ground deformations, and operational data collected from the ongoing monitoring episode (Wysin) and past episodes: Lubocino (Poland), Preese Hall (UK), Oklahoma (USA

  9. Exploitation: One View of Industry and Business. Training and Development Research Center: Project Number Ten.

    ERIC Educational Resources Information Center

    Swanson, Richard A.; And Others

    A reasonable definition of exploitation is an unjust or improper use of another person for one's own profit or advantage. Exploitation predates the age of industry; it is not the sole province of industry and business. Worker responses to exploitation in the evolving industrial democracy have taken the form of labor unions, political clubs, credit…

  10. 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…

  11. 25 CFR 20.516 - How are child abuse, neglect or exploitation cases to be handled?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false How are child abuse, neglect or exploitation cases to be... FINANCIAL ASSISTANCE AND SOCIAL SERVICES PROGRAMS Child Assistance Foster Care § 20.516 How are child abuse, neglect or exploitation cases to be handled? Reported child abuse, neglect or exploitation cases and the...

  12. 25 CFR 20.516 - How are child abuse, neglect or exploitation cases to be handled?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false How are child abuse, neglect or exploitation cases to be... FINANCIAL ASSISTANCE AND SOCIAL SERVICES PROGRAMS Child Assistance Foster Care § 20.516 How are child abuse, neglect or exploitation cases to be handled? Reported child abuse, neglect or exploitation cases and the...

  13. 25 CFR 20.516 - How are child abuse, neglect or exploitation cases to be handled?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How are child abuse, neglect or exploitation cases to be... FINANCIAL ASSISTANCE AND SOCIAL SERVICES PROGRAMS Child Assistance Foster Care § 20.516 How are child abuse, neglect or exploitation cases to be handled? Reported child abuse, neglect or exploitation cases and the...

  14. 25 CFR 20.516 - How are child abuse, neglect or exploitation cases to be handled?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true How are child abuse, neglect or exploitation cases to be... FINANCIAL ASSISTANCE AND SOCIAL SERVICES PROGRAMS Child Assistance Foster Care § 20.516 How are child abuse, neglect or exploitation cases to be handled? Reported child abuse, neglect or exploitation cases and the...

  15. A Low-Cost Quantitative Absorption Spectrophotometer

    ERIC Educational Resources Information Center

    Albert, Daniel R.; Todt, Michael A.; Davis, H. Floyd

    2012-01-01

    In an effort to make absorption spectrophotometry available to high school chemistry and physics classes, we have designed an inexpensive visible light absorption spectrophotometer. The spectrophotometer was constructed using LEGO blocks, a light emitting diode, optical elements (including a lens), a slide-mounted diffraction grating, and a…

  16. Do Atoms Really "Emit" Absorption Lines?

    ERIC Educational Resources Information Center

    Brecher, Kenneth

    1991-01-01

    Presents three absorption line sources that enhance student understanding of the phenomena associated with the interaction of light with matter and help dispel the misconception that atoms "emit" absorption lines. Sources include neodymium, food coloring and other common household liquids, and fluorescent materials. (MDH)

  17. Absorption of sound by tree bark

    Treesearch

    G. Reethof; L. D. Frank; O. H. McDaniel

    1976-01-01

    Laboratory tests were conducted with a standing wave tube to measure the acoustic absorption of normally incident sound by the bark of six species of trees. Twelve bark samples, 10 cm in diameter, were tested. Sound of seven frequencies between 400 and 1600 Hz was used in the measurements. Absorption was generally about 5 percent; it exceeded 10 percent for only three...

  18. Photoelectric absorption cross sections with variable abundances

    NASA Technical Reports Server (NTRS)

    Balucinska-Church, Monika; Mccammon, Dan

    1992-01-01

    Polynomial fit coefficients have been obtained for the energy dependences of the photoelectric absorption cross sections of 17 astrophysically important elements. These results allow the calculation of X-ray absorption in the energy range 0.03-10 keV in material with noncosmic abundances.

  19. Low absorptance porcelain-on-aluminum coating

    NASA Technical Reports Server (NTRS)

    Leggett, H.

    1979-01-01

    Porcelain thermal-control coating for aluminum sheet and foil has solar absorptance of 0.22. Specially formulated coating absorptance is highly stable, changing only 0.03 after 1,000 hours of exposure to simulated sunlight and can be applied by standard commercial methods.

  20. Iron absorption from intrinsically-labeled lentils

    USDA-ARS?s Scientific Manuscript database

    Low iron (Fe) absorption from important staple foods may contribute to Fe deficiency in developing countries. To date, there are few studies examining the Fe bioavailability of pulse crops as commonly prepared and consumed by humans. The objectives of this study were to characterize the Fe absorpt...

  1. Nonlinear Absorption and Heating of Dense Plasmas.

    DTIC Science & Technology

    plasma focus both illuminated by a high intensity CO2 laser. Results indicate the previously noted increases in absorption due to the inclusion of the nonlinear saturation mechanism. The previously obtained increases in absorption with increasing density scale height and decreasing temperatures are also recovered. The

  2. High-Absorptance Radiative Heat Sink

    NASA Technical Reports Server (NTRS)

    Cafferty, T.

    1983-01-01

    Absorptance of black-painted open-cell aluminum honeycomb improved by cutting honeycomb at angle or bias rather than straight across. This ensures honeycomb cavities escapes. At each reflection radiation attenuated by absorption. Applications include space-background simulators, space radiators, solar absorbers, and passive coolers for terrestrial use.

  3. 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.

  4. 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. © The Author(s) 2015.

  5. Program for the exploitation of unused NASA patents

    NASA Technical Reports Server (NTRS)

    Fay, R. J.

    1972-01-01

    The program to exploit unused NASA patents through the use of a multidisciplinary approach involving faculty students, and research staff is reported. NASA patents were screened for their applicability outside the space program, specific applications were identified, and the technical and commercial feasibility of these applications was established. Also application of this technology by governmental agencies outside the space program was sought. The program was specifically interested in energy absorbing devices such as those developed for lunar soft landings. These energy absorbing devices absorb large amounts of mechanical energy but are, in general, not reusable. Some of these devices can also operate as structural elements until their structural load capacity is exceeded and they become activated as energy absorbers. The capability of these devices to operate as structural elements and as energy absorbing devices makes them candidates for many applications in the fields of transportation and materials handling safety where accidents take a large toll in human injury and property damage.

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

    SciTech Connect

    Schallenberger, A.

    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 somemore » 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.« less

  7. Exploiting Motion Capture to Enhance Avoidance Behaviour in Games

    NASA Astrophysics Data System (ADS)

    van Basten, Ben J. H.; Jansen, Sander E. M.; Karamouzas, Ioannis

    Realistic simulation of interacting virtual characters is essential in computer games, training and simulation applications. The problem is very challenging since people are accustomed to real-world situations and thus, they can easily detect inconsistencies and artifacts in the simulations. Over the past twenty years several models have been proposed for simulating individuals, groups and crowds of characters. However, little effort has been made to actually understand how humans solve interactions and avoid inter-collisions in real-life. In this paper, we exploit motion capture data to gain more insights into human-human interactions. We propose four measures to describe the collision-avoidance behavior. Based on these measures, we extract simple rules that can be applied on top of existing agent and force based approaches, increasing the realism of the resulting simulations.

  8. Exploiting Helminth-Host Interactomes through Big Data.

    PubMed

    Sotillo, Javier; Toledo, Rafael; Mulvenna, Jason; Loukas, Alex

    2017-11-01

    Helminths facilitate their parasitic existence through the production and secretion of different molecules, including proteins. Some helminth proteins can manipulate the host's immune system, a phenomenon that is now being exploited with a view to developing therapeutics for inflammatory diseases. In recent years, hundreds of helminth genomes have been sequenced, but as a community we are still taking baby steps when it comes to identifying proteins that govern host-helminth interactions. The information generated from genomic, immunomic, and proteomic studies, as well as from cutting-edge approaches such as proteogenomics, is leading to a substantial volume of big data that can be utilised to shed light on fundamental biology and provide solutions for the development of bioactive-molecule-based therapeutics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Exploiting CRISPR-Cas to manipulate Enterococcus faecalis populations.

    PubMed

    Hullahalli, Karthik; Rodrigues, Marinelle; Palmer, Kelli L

    2017-06-23

    CRISPR-Cas provides a barrier to horizontal gene transfer in prokaryotes. It was previously observed that functional CRISPR-Cas systems are absent from multidrug-resistant (MDR) Enterococcus faecalis , which only possess an orphan CRISPR locus, termed CRISPR2, lacking cas genes. Here, we investigate how the interplay between CRISPR-Cas genome defense and antibiotic selection for mobile genetic elements shapes in vitro E. faecalis populations. We demonstrate that CRISPR2 can be reactivated for genome defense in MDR strains. Interestingly, we observe that E. faecalis transiently maintains CRISPR targets despite active CRISPR-Cas systems. Subsequently, if selection for the CRISPR target is present, toxic CRISPR spacers are lost over time, while in the absence of selection, CRISPR targets are lost over time. We find that forced maintenance of CRISPR targets induces a fitness cost that can be exploited to alter heterogeneous E. faecalis populations.

  10. Exploiting CRISPR/Cas: Interference Mechanisms and Applications

    PubMed Central

    Richter, Hagen; Randau, Lennart; Plagens, André

    2013-01-01

    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. PMID:23857052

  11. Exploiting bistable oscillator subharmonics for magnified broadband vibration energy harvesting

    NASA Astrophysics Data System (ADS)

    Huguet, Thomas; Badel, Adrien; Lallart, Mickaël

    2017-10-01

    Recent research on primary battery alternatives for supplying autonomous wireless devices has recently highlighted the advantages of nonlinear oscillators' dynamics and more particularly bistable oscillators' behavior for ambient vibration harvesting. The key property of bistable oscillators compared to linear ones is their enhanced operational frequency bandwidth under harmonic excitation, potentially leading to a better adaptation to the environment. However, the classical frequency response characterization of such devices does not reveal all the possible dynamic behaviors offered by bistable oscillators. Thus, subharmonic motions are experimentally investigated in this letter, and their energy harvesting potential as well as their ability to enhance the bistable generator bandwidth is evaluated. The results obtained with a generator integrating buckled beams for the bistability feature show that, in addition to the commonly considered harmonic behavior, subharmonics allow widening of the useful operating frequency band of the bistable microgenerator by 180% compared to the sole exploitation of the first harmonic motion.

  12. Tricking the guard: exploiting plant defense for disease susceptibility.

    PubMed

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

    2012-11-02

    Typically, pathogens deploy virulence effectors to disable defense. Plants defeat effectors with resistance proteins that guard effector targets. We found that a pathogen exploits a resistance protein by activating it to confer susceptibility in Arabidopsis. The guard mechanism of plant defense is recapitulated by interactions among victorin (an effector produced by the necrotrophic fungus Cochliobolus victoriae), TRX-h5 (a defense-associated thioredoxin), and LOV1 (an Arabidopsis susceptibility protein). 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 that 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.

  13. Synthetic biology approaches: Towards sustainable exploitation of marine bioactive molecules.

    PubMed

    Seghal Kiran, G; Ramasamy, Pasiyappazham; Sekar, Sivasankari; Ramu, Meenatchi; Hassan, Saqib; Ninawe, A S; Selvin, Joseph

    2018-06-01

    The discovery of genes responsible for the production of bioactive metabolites via metabolic pathways combined with the advances in synthetic biology tools, has allowed the establishment of numerous microbial cell factories, for instance the yeast cell factories, for the manufacture of highly useful metabolites from renewable biomass. Genome mining and metagenomics are two platforms provide base-line data for reconstruction of genomes and metabolomes which is based in the development of synthetic/semi-synthetic genomes for marine natural products discovery. Engineered biofilms are being innovated on synthetic biology platform using genetic circuits and cell signalling systems as represillators controlling biofilm formation. Recombineering is a process of homologous recombination mediated genetic engineering, includes insertion, deletion or modification of any sequence specifically. Although this discipline considered new to the scientific domain, this field has now developed as promising endeavor on the accomplishment of sustainable exploitation of marine natural products. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Exploiting Self-organization in Bioengineered Systems: A Computational Approach.

    PubMed

    Davis, Delin; Doloman, Anna; Podgorski, Gregory J; Vargis, Elizabeth; Flann, Nicholas S

    2017-01-01

    The productivity of bioengineered cell factories is limited by inefficiencies in nutrient delivery and waste and product removal. Current solution approaches explore changes in the physical configurations of the bioreactors. This work investigates the possibilities of exploiting self-organizing vascular networks to support producer cells within the factory. A computational model simulates de novo vascular development of endothelial-like cells and the resultant network functioning to deliver nutrients and extract product and waste from the cell culture. Microbial factories with vascular networks are evaluated for their scalability, robustness, and productivity compared to the cell factories without a vascular network. Initial studies demonstrate that at least an order of magnitude increase in production is possible, the system can be scaled up, and the self-organization of an efficient vascular network is robust. The work suggests that bioengineered multicellularity may offer efficiency improvements difficult to achieve with physical engineering approaches.

  15. 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.

  16. Exploitation and Benefits of BIM in Construction Project Management

    NASA Astrophysics Data System (ADS)

    Mesároš, Peter; Mandičák, Tomáš

    2017-10-01

    BIM is increasingly getting into the awareness in construction industry. BIM is the process of creating and data managing of the building during its life cycle. BIM became a part of management tools in modern construction companies. Construction projects have a number of participants. It means difficulty process of construction project management and a serious requirement for processing the huge amount of information including design, construction, time and cost parameters, economic efficiency and sustainability. Progressive information and communication technologies support cost management and management of construction project. One of them is Building Information Modelling. Aim of the paper is to examine the impact of BIM exploitation and benefits on construction project management in Slovak companies.

  17. 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.

  18. Analysis of ecological environment impact of coal exploitation and utilization

    NASA Astrophysics Data System (ADS)

    Zhang, Baoliu; Luo, Hong; Lv, Lianhong; Wang, Jian; Zhang, Baoshi

    2018-02-01

    Based on the theory of life cycle assessment, the ecological and environmental impacts of coal mining, processing, utilization and transportation will be analyzed, with analysing the status of china’s coal exploitation and utilization as the basis, it will find out the ecological and environmental impact in the development and utilization of coal, mainly consist of ecological impact including land damage, water resource destructionand biodiversity loss, etc., while the environmental impact include air, water, solid waste pollutions. Finally with a summary of the ecological and environmental problems, to propose solutionsand countermeasures to promote the rational development and consumption of coal, as well as to reduce the impact of coal production and consumption on the ecological environment, finally to achieve the coordinated development of energy and the environment.

  19. Food Ingredients That Inhibit Cholesterol Absorption

    PubMed Central

    Jesch, Elliot D.; Carr, Timothy P.

    2017-01-01

    Cholesterol is a vital component of the human body. It stabilizes cell membranes and is the precursor of bile acids, vitamin D and steroid hormones. However, cholesterol accumulation in the bloodstream (hypercholesterolemia) can cause atherosclerotic plaques within artery walls, leading to heart attacks and strokes. The efficiency of cholesterol absorption in the small intestine is of great interest because human and animal studies have linked cholesterol absorption with plasma concentration of total and low density lipoprotein cholesterol. Cholesterol absorption is highly regulated and influenced by particular compounds in the food supply. Therefore, it is desirable to learn more about natural food components that inhibit cholesterol absorption so that food ingredients and dietary supplements can be developed for consumers who wish to manage their plasma cholesterol levels by non-pharmacological means. Food components thus far identified as inhibitors of cholesterol absorption include phytosterols, soluble fibers, phospholipids, and stearic acid. PMID:28702423

  20. 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

  1. Detect and exploit hidden structure in fatty acid signature data

    USGS Publications Warehouse

    Budge, Suzanne; Bromaghin, Jeffrey F.; Thiemann, Gregory

    2017-01-01

    Estimates of predator diet composition are essential to our understanding of their ecology. Although several methods of estimating diet are practiced, methods based on biomarkers have become increasingly common. Quantitative fatty acid signature analysis (QFASA) is a popular method that continues to be refined and extended. Quantitative fatty acid signature analysis is based on differences in the signatures of prey types, often species, which are recognized and designated by investigators. Similarly, predator signatures may be structured by known factors such as sex or age class, and the season or region of sample collection. The recognized structure in signature data inherently influences QFASA results in important and typically beneficial ways. However, predator and prey signatures may contain additional, hidden structure that investigators either choose not to incorporate into an analysis or of which they are unaware, being caused by unknown ecological mechanisms. Hidden structure also influences QFASA results, most often negatively. We developed a new method to explore signature data for hidden structure, called divisive magnetic clustering (DIMAC). Our DIMAC approach is based on the same distance measure used in diet estimation, closely linking methods of data exploration and parameter estimation, and it does not require data transformation or distributional assumptions, as do many multivariate ordination methods in common use. We investigated the potential benefits of the DIMAC method to detect and subsequently exploit hidden structure in signature data using two prey signature libraries with quite different characteristics. We found that the existence of hidden structure in prey signatures can increase the confusion between prey types and thereby reduce the accuracy and precision of QFASA diet estimates. Conversely, the detection and exploitation of hidden structure represent a potential opportunity to improve predator diet estimates and may lead to new

  2. 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.

  3. Sensor Exposure, Exploitation, and Experimentation Environment (SE4)

    NASA Astrophysics Data System (ADS)

    Buell, D.; Duff, F.; Goding, J.; Bankston, M.; McLaughlin, T.; Six, S.; Taylor, S.; Wootton, S.

    2011-09-01

    As the resident space object population increases from new launches and events such as the COSMOS/IRIDIUM collision, the maintenance of high-level Space Situational Awareness (SSA) has become increasingly difficult. To maintain situational awareness of the changing environment, new systems and methods must be developed. The Sensor Exposure, Exploitation and Experimentation Environment (SE4) provides a platform to illustrate “The Art of the Possible” that shows the potential benefit of enriched sensor data collections and real-time data sharing. Through modeling and simulation, and a net-centric architecture, SE4 shows the added value of sharing data in real-time and exposing new types of sensor data. The objective of SE4 is to develop an experimentation and innovation environment for sensor data exposure, composable sensor capabilities, reuse, and exploitation that accelerates the delivery of needed Command and Control, Intelligence, Surveillance, and Reconnaissance capabilities to the warfighter. Through modeling, simulation and rapid prototyping, the art of the possible for a fully-connected, net-centric space Command and Control (C2) and sensor enterprise can be demonstrated. This paper provides results that demonstrate the potential for faster cataloging of breakup events and additional event monitoring that are possible with data available today in the Space Surveillance Network (SSN). Demonstrating the art of the possible for the enterprise will guide net-centric requirements definition and facilitate discussions with stakeholder organizations on the Concept of Operations (CONOPS), policy, and Tactics, Techniques, and Procedures (TTP) evolution necessary to take full advantage of net-centric operations. SE4 aligns with direction from Secretary Gates and the Chairman Joint Chief of Staff that emphasizes the need to get the most out of our existing systems. Continuing to utilize SE4 will enable the enterprise by demonstrating the benefits of applying

  4. Exploiting risk-reward structures in decision making under uncertainty.

    PubMed

    Leuker, Christina; Pachur, Thorsten; Hertwig, Ralph; Pleskac, Timothy J

    2018-06-01

    People often have to make decisions under uncertainty-that is, in situations where the probabilities of obtaining a payoff are unknown or at least difficult to ascertain. One solution to this problem is to infer the probability from the magnitude of the potential payoff and thus exploit the inverse relationship between payoffs and probabilities that occurs in many domains in the environment. Here, we investigated how the mind may implement such a solution: (1) Do people learn about risk-reward relationships from the environment-and if so, how? (2) How do learned risk-reward relationships impact preferences in decision-making under uncertainty? Across three experiments (N = 352), we found that participants can learn risk-reward relationships from being exposed to choice environments with a negative, positive, or uncorrelated risk-reward relationship. They were able to learn the associations both from gambles with explicitly stated payoffs and probabilities (Experiments 1 & 2) and from gambles about epistemic events (Experiment 3). In subsequent decisions under uncertainty, participants often exploited the learned association by inferring probabilities from the magnitudes of the payoffs. This inference systematically influenced their preferences under uncertainty: Participants who had been exposed to a negative risk-reward relationship tended to prefer the uncertain option over a smaller sure option for low payoffs, but not for high payoffs. This pattern reversed in the positive condition and disappeared in the uncorrelated condition. This adaptive change in preferences is consistent with the use of the risk-reward heuristic. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Time-dependent oral absorption models

    NASA Technical Reports Server (NTRS)

    Higaki, K.; Yamashita, S.; Amidon, G. L.

    2001-01-01

    The plasma concentration-time profiles following oral administration of drugs are often irregular and cannot be interpreted easily with conventional models based on first- or zero-order absorption kinetics and lag time. Six new models were developed using a time-dependent absorption rate coefficient, ka(t), wherein the time dependency was varied to account for the dynamic processes such as changes in fluid absorption or secretion, in absorption surface area, and in motility with time, in the gastrointestinal tract. In the present study, the plasma concentration profiles of propranolol obtained in human subjects following oral dosing were analyzed using the newly derived models based on mass balance and compared with the conventional models. Nonlinear regression analysis indicated that the conventional compartment model including lag time (CLAG model) could not predict the rapid initial increase in plasma concentration after dosing and the predicted Cmax values were much lower than that observed. On the other hand, all models with the time-dependent absorption rate coefficient, ka(t), were superior to the CLAG model in predicting plasma concentration profiles. Based on Akaike's Information Criterion (AIC), the fluid absorption model without lag time (FA model) exhibited the best overall fit to the data. The two-phase model including lag time, TPLAG model was also found to be a good model judging from the values of sum of squares. This model also described the irregular profiles of plasma concentration with time and frequently predicted Cmax values satisfactorily. A comparison of the absorption rate profiles also suggested that the TPLAG model is better at prediction of irregular absorption kinetics than the FA model. In conclusion, the incorporation of a time-dependent absorption rate coefficient ka(t) allows the prediction of nonlinear absorption characteristics in a more reliable manner.

  6. Monitoring Telluric Absorption with CAMAL

    NASA Astrophysics Data System (ADS)

    Baker, Ashley D.; Blake, Cullen H.; Sliski, David H.

    2017-08-01

    Ground-based astronomical observations may be limited by telluric water vapor absorption, which is highly variable in time and significantly complicates both spectroscopy and photometry in the near-infrared (NIR). To achieve the sensitivity required to detect Earth-sized exoplanets in the NIR, simultaneous monitoring of precipitable water vapor (PWV) becomes necessary to mitigate the impact of variable telluric lines on radial velocity measurements and transit light curves. To address this issue, we present the Camera for the Automatic Monitoring of Atmospheric Lines (CAMAL), a stand-alone, inexpensive six-inch aperture telescope dedicated to measuring PWV at the Fred Lawrence Whipple Observatory on Mount Hopkins. CAMAL utilizes three narrowband NIR filters to trace the amount of atmospheric water vapor affecting simultaneous observations with the MINiature Exoplanet Radial Velocity Array (MINERVA) and MINERVA-Red telescopes. Here, we present the current design of CAMAL, discuss our data analysis methods, and show results from 11 nights of PWV measurements taken with CAMAL. For seven nights of data we have independent PWV measurements extracted from high-resolution stellar spectra taken with the Tillinghast Reflector Echelle Spectrometer (TRES) also located on Mount Hopkins. We use the TRES spectra to calibrate the CAMAL absolute PWV scale. Comparisons between CAMAL and TRES PWV estimates show excellent agreement, matching to within 1 mm over a 10 mm range in PWV. Analysis of CAMAL’s photometric precision propagates to PWV measurements precise to better than 0.5 mm in dry (PWV < 4 mm) conditions. We also find that CAMAL-derived PWVs are highly correlated with those from a GPS-based water vapor monitor located approximately 90 km away at Kitt Peak National Observatory, with a root mean square PWV difference of 0.8 mm.

  7. A structure preserving Lanczos algorithm for computing the optical absorption spectrum

    SciTech Connect

    Shao, Meiyue; Jornada, Felipe H. da; Lin, Lin

    2016-11-16

    We present a new structure preserving Lanczos algorithm for approximating the optical absorption spectrum in the context of solving full Bethe-Salpeter equation without Tamm-Dancoff approximation. The new algorithm is based on a structure preserving Lanczos procedure, which exploits the special block structure of Bethe-Salpeter Hamiltonian matrices. A recently developed technique of generalized averaged Gauss quadrature is incorporated to accelerate the convergence. We also establish the connection between our structure preserving Lanczos procedure with several existing Lanczos procedures developed in different contexts. Numerical examples are presented to demonstrate the effectiveness of our Lanczos algorithm.

  8. Coherence in the presence of absorption and heating in a molecule interferometer

    PubMed Central

    Cotter, J. P.; Eibenberger, S.; Mairhofer, L.; Cheng, X.; Asenbaum, P.; Arndt, M.; Walter, K.; Nimmrichter, S.; Hornberger, K.

    2015-01-01

    Matter-wave interferometry can be used to probe the foundations of physics and to enable precise measurements of particle properties and fundamental constants. It relies on beam splitters that coherently divide the wave function. In atom interferometers, such elements are often realised using lasers by exploiting the dipole interaction or through photon absorption. It is intriguing to extend these ideas to complex molecules where the energy of an absorbed photon can rapidly be redistributed across many internal degrees of freedom. Here, we provide evidence that center-of-mass coherence can be maintained even when the internal energy and entropy of the interfering particle are substantially increased by absorption of photons from a standing light wave. Each photon correlates the molecular center-of-mass wave function with its internal temperature and splits it into a superposition with opposite momenta in addition to the beam-splitting action of the optical dipole potential. PMID:26066053

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

    PubMed Central

    HOLGER-AMBROSE, BETH; LANGMADE, CHEREE; EDINBURGH, LAUREL D.; SAEWYC, ELIZABETH

    2015-01-01

    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 14–22, in a Midwestern U.S. city. Participants reported multiple types of exploitation, most first exploited by age 13, plus substance use, and recurrent homelessness. Nearly all had a pimp, and all used the internet as a venue for sexual exploitation. Participants wanted outreach workers to use “soft words” to refer to exploitation. They expressed contradictory images of their “boyfriend” pimps and their exploitation. They wanted outreach workers to “provide resources,” “be non-judgmental,” ”listen,” and “care.” Street outreach can be one way to support sexually exploited youth, but should occur in multiple settings. PMID:23590353

  10. Variance of transionospheric VLF wave power absorption

    NASA Astrophysics Data System (ADS)

    Tao, X.; Bortnik, J.; Friedrich, M.

    2010-07-01

    To investigate the effects of D-region electron-density variance on wave power absorption, we calculate the power reduction of very low frequency (VLF) waves propagating through the ionosphere with a full wave method using the standard ionospheric model IRI and in situ observational data. We first verify the classic absorption curves of Helliwell's using our full wave code. Then we show that the IRI model gives overall smaller wave absorption compared with Helliwell's. Using D-region electron densities measured by rockets during the past 60 years, we demonstrate that the power absorption of VLF waves is subject to large variance, even though Helliwell's absorption curves are within ±1 standard deviation of absorption values calculated from data. Finally, we use a subset of the rocket data that are more representative of the D region of middle- and low-latitude VLF wave transmitters and show that the average quiet time wave absorption is smaller than that of Helliwell's by up to 100 dB at 20 kHz and 60 dB at 2 kHz, which would make the model-observation discrepancy shown by previous work even larger. This result suggests that additional processes may be needed to explain the discrepancy.

  11. The effect of volatility on percutaneous absorption.

    PubMed

    Rouse, Nicole C; Maibach, Howard I

    2016-01-01

    Topically applied chemicals may volatilize, or evaporate, from skin leaving behind a chemical residue with new percutaneous absorptive capabilities. Understanding volatilization of topical medications, such as sunscreens, fragrances, insect repellants, cosmetics and other commonly applied topicals may have implications for their safety and efficacy. A systematic review of English language articles from 1979 to 2014 was performed using key search terms. Articles were evaluated to assess the relationship between volatility and percutaneous absorption. A total of 12 articles were selected and reviewed. Key findings were that absorption is enhanced when coupled with a volatile substance, occlusion prevents evaporation and increases absorption, high ventilation increases volatilization and reduces absorption, and pH of skin has an affect on a chemical's volatility. The articles also brought to light that different methods may have an affect on volatility: different body regions; in vivo vs. in vitro; human vs. Data suggest that volatility is crucial for determining safety and efficacy of cutaneous exposures and therapies. Few articles have been documented reporting evaporation in the context of percutaneous absorption, and of those published, great variability exists in methods. Further investigation of volatility is needed to properly evaluate its role in percutaneous absorption.

  12. Glucose absorption in acute peritoneal dialysis.

    PubMed

    Podel, J; Hodelin-Wetzel, R; Saha, D C; Burns, G

    2000-04-01

    During acute peritoneal dialysis (APD), it is known that glucose found in the dialysate solution contributes to the provision of significant calories. It has been well documented in continuous ambulatory peritoneal dialysis (CAPD) that glucose absorption occurs. In APD, however, it remains unclear how much glucose absorption actually does occur. Therefore, the purpose of this study was to determine whether it is appropriate to use the formula used to calculate glucose absorption in CAPD (Grodstein et al) among patients undergoing APD. Actual measurements of glucose absorption (Method I) were calculated in 9 patients undergoing APD treatment for >24 hours who were admitted to the intensive care unit. Glucose absorption using the Grodstein et al formula (Method II) was also determined and compared with the results of actual measurements. The data was then further analyzed based on the factors that influence glucose absorption, specifically dwell time and concentration. The mean total amount of glucose absorbed was 43% +/- 15%. However, when dwell time and concentration were further examined, significant differences were noted. Method I showed a cumulative increase over time. Method II showed that absorption was fixed. This suggests that with the variation in dwell time commonly seen in the acute care setting, the use of Method II may not be accurate. In each of the 2 methods, a significant difference in glucose absorption was noted when comparing the use of 1.5% and 4.25% dialysate concentrations. The established formula designed for CAPD should not be used for calculating glucose absorption in patients receiving APD because variation in dwell time and concentration should be taken into account. Because of the time constraints and staffing required to calculate each exchange individually, combined with the results of the study, we recommend the use of the percentage estimate of 40% to 50%.

  13. The ESA Scientific Exploitation of Operational Missions element

    NASA Astrophysics Data System (ADS)

    Desnos, Yves-Louis; Regner, Peter; Zehner, Claus; Engdahl, Marcus; Benveniste, Jerome; Delwart, Steven; Gascon, Ferran; Mathieu, Pierre-Philippe; Bojkov, Bojan; Koetz, Benjamin; Arino, Olivier; Donlon, Craig; Davidson, Malcolm; Goryl, Philippe; Foumelis, Michael

    2014-05-01

    The objectives of the ESA Scientific Exploitation of Operational Missions (SEOM) programme element are • to federate, support and expand the research community • to strengthen the leadership of European EO research community • to enable the science community to address new scientific research As a preparation for the SEOM element a series of international science users consultation has been organized by ESA in 2012 and 2013 In particular the ESA Living Planet Symposium was successfully organized in Edinburgh September 2013 and involving 1700 participants from 60 countries. The science users recommendations have been gathered and form the basis for the 2014 SEOM work plan approved by ESA member states. The SEOM element is organized along the following action lines: 1. Developing open-source, multi-mission, scientific toolboxes : the new toolboxes for Sentinel 1/2/3 and 5P will be introduced 2. Research and development studies: the first SEOM studies are being launched such as the INSARAP studies for Sentinel 1 interferometry in orbit demonstration , the IAS study to generate an improved spectroscopic database of the trace gas species CH4, H2O, and CO in the 2.3 μm region and SO2 in the UV region for Sentinel 5 P. In addition larger Sentinels for science call will be tendered in 2014 covering grouped studies for Sentinel 1 Land , Sentinel 1 Ocean , Sentinel 2 Land, Sentinel 3 SAR Altimetry ,Sentinel 3 Ocean color, Sentinel 3 Land and Sentinels Synergy . 3. Science users consultation : the Sentinel 2 for Science workshop is planned from 20 to 22 may 2014 at ESRIN to prepare for scientific exploitation of the Sentinel-2 mission (http://seom.esa.int/S2forScience2014 ) . In addition the FRINGE workshop focusing on scientific explotation of Sentinel1 using SAR interferometry is planned to be held at ESA ESRIN in Q2 2015 4. Training the next generation of European EO scientists on the scientific exploitation of Sentinels data: the Advanced Training course Land

  14. 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

  15. Psychological absorption. Affect investment in marijuana intoxication.

    PubMed

    Fabian, W D; Fishkin, S M

    1991-01-01

    Absorption (a trait capacity for total attentional involvement) was reported to increase during episodes of marijuana intoxication. Several subsets of the absorption scale items specifically characterized marijuana intoxication, and groups of users and nonusers showed differential affective involvement with these experiences. Additionally, within the drug-using group, a positive correlation between frequency of marijuana use and affective ratings of these experiences was found. The findings support the hypothesis that a specific type of alteration in consciousness that enhances capacity for total attentional involvement (absorption) characterizes marijuana intoxication, and that this enhancement may act as a reinforcer, possibly influencing future use.

  16. The effect of tea on iron absorption.

    PubMed Central

    Disler, P B; Lynch, S R; Charlton, R W; Torrance, J D; Bothwell, T H; Walker, R B; Mayet, F

    1975-01-01

    The effect of tea on iron absorption was studied in human volunteers. Absorption from solutions of FeCl3 and FeSO4, bread, a meal of rice with potato and onion soup, and uncooked haemoglobin was inhibited whether ascorbic acid was present or not. No inhibition was noted if the haemoglobin was cooked. The effect on the absorption of non-haem iron was ascribed to the formation of insoluble iron tannate complexes. Drinking tannin-containing beverages such as tea with meals may contribute to the pathogenesis of iron deficiency if the diet consists largely of vegetable foodstuffs. PMID:1168162

  17. Nonlinear absorption properties of silicene nanosheets.

    PubMed

    Zhang, Fang; Wang, Mengxia; Wang, Zhengping; Han, Kezhen; Liu, Xiaojuan; Xu, Xinguang

    2018-06-01

    As the cousins of graphene, i.e. same group IVA element, the nonlinear absorption (NLA) properties of silicene nanosheets were rarely studied. In this paper, we successfully exfoliated the two-dimensional silicene nanosheets from bulk silicon crystal using liquid phase exfoliation method. The NLA properties of silicene nanosheets were systemically investigated for the first time, as we have known. Silicene performed exciting saturable absorption and two photon absorption (2PA) behavior. The lower saturable intensity and larger 2PA coefficient at 532 nm excitation indicates that silicene has potential application in ultrafast lasers and optical limiting devices, especially in visible waveband.

  18. Selective coherent perfect absorption in metamaterials

    SciTech Connect

    Nie, Guangyu; Shi, Quanchao; Zhu, Zheng

    2014-11-17

    We show multi-band coherent perfect absorption (CPA) in simple bilayered asymmetrically split ring metamaterials. The selectivity of absorption can be accomplished by separately excited electric and magnetic modes in a standing wave formed by two coherent counterpropagating beams. In particular, each CPA can be completely switched on/off by the phase of a second coherent wave. We propose a practical scheme for realizing multi-band coherent perfect absorption of 100% that is allowed to work from microwave to optical frequency.

  19. Nonlinear absorption properties of silicene nanosheets

    NASA Astrophysics Data System (ADS)

    Zhang, Fang; Wang, Mengxia; Wang, Zhengping; Han, Kezhen; Liu, Xiaojuan; Xu, Xinguang

    2018-06-01

    As the cousins of graphene, i.e. same group IVA element, the nonlinear absorption (NLA) properties of silicene nanosheets were rarely studied. In this paper, we successfully exfoliated the two-dimensional silicene nanosheets from bulk silicon crystal using liquid phase exfoliation method. The NLA properties of silicene nanosheets were systemically investigated for the first time, as we have known. Silicene performed exciting saturable absorption and two photon absorption (2PA) behavior. The lower saturable intensity and larger 2PA coefficient at 532 nm excitation indicates that silicene has potential application in ultrafast lasers and optical limiting devices, especially in visible waveband.

  20. Sound absorption by a Helmholtz resonator

    NASA Astrophysics Data System (ADS)

    Komkin, A. I.; Mironov, M. A.; Bykov, A. I.

    2017-07-01

    Absorption characteristics of a Helmholtz resonator positioned at the end wall of a circular duct are considered. The absorption coefficient of the resonator is experimentally investigated as a function of the diameter and length of the resonator neck and the depth of the resonator cavity. Based on experimental data, the linear analytic model of a Helmholtz resonator is verified, and the results of verification are used to determine the dissipative attached length of the resonator neck so as to provide the agreement between experimental and calculated data. Dependences of sound absorption by a Helmholtz resonator on its geometric parameters are obtained.

  1. Mathematical models and photogrammetric exploitation of image sensing

    NASA Astrophysics Data System (ADS)

    Puatanachokchai, Chokchai

    Mathematical models of image sensing are generally categorized into physical/geometrical sensor models and replacement sensor models. While the former is determined from image sensing geometry, the latter is based on knowledge of the physical/geometric sensor models and on using such models for its implementation. The main thrust of this research is in replacement sensor models which have three important characteristics: (1) Highly accurate ground-to-image functions; (2) Rigorous error propagation that is essentially of the same accuracy as the physical model; and, (3) Adjustability, or the ability to upgrade the replacement sensor model parameters when additional control information becomes available after the replacement sensor model has replaced the physical model. In this research, such replacement sensor models are considered as True Replacement Models or TRMs. TRMs provide a significant advantage of universality, particularly for image exploitation functions. There have been several writings about replacement sensor models, and except for the so called RSM (Replacement Sensor Model as a product described in the Manual of Photogrammetry), almost all of them pay very little or no attention to errors and their propagation. This is because, it is suspected, the few physical sensor parameters are usually replaced by many more parameters, thus presenting a potential error estimation difficulty. The third characteristic, adjustability, is perhaps the most demanding. It provides an equivalent flexibility to that of triangulation using the physical model. Primary contributions of this thesis include not only "the eigen-approach", a novel means of replacing the original sensor parameter covariance matrices at the time of estimating the TRM, but also the implementation of the hybrid approach that combines the eigen-approach with the added parameters approach used in the RSM. Using either the eigen-approach or the hybrid approach, rigorous error propagation can be

  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

    Alfson, Kendra J; Worwa, Gabriella; Carrion, Ricardo; Griffiths, Anthony

    2015-12-16

    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. 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 changes were not well

  4. Lipid-associated Oral Delivery: Mechanisms and Analysis of Oral Absorption Enhancement

    PubMed Central

    Rezhdo, Oljora; Speciner, Lauren; Carrier, Rebecca L.

    2016-01-01

    The majority of newly discovered oral drugs are poorly water soluble, and co-administration with lipids has proven effective in significantly enhancing bioavailability of some compounds with low aqueous solubility. Yet, lipid-based delivery technologies have not been widely employed in commercial oral products. Lipids can impact drug transport and fate in the gastrointestinal (GI) tract through multiple mechanisms including enhancement of solubility and dissolution kinetics, enhancement of permeation through the intestinal mucosa, and triggering drug precipitation upon lipid emulsion depletion (e.g., by digestion). The effect of lipids on drug absorption is currently not quantitatively predictable, in part due to the multiple complex dynamic processes that can be impacted by lipids. Quantitative mechanistic analysis of the processes significant to lipid system function and overall impact on drug absorption can aid understanding of drug-lipid interactions in the GI tract and exploitation of such interactions to achieve optimal lipid-based drug delivery. In this review, we discuss the impact of co-delivered lipids and lipid digestion on drug dissolution, partitioning, and absorption in the context of the experimental tools and associated kinetic expressions used to study and model these processes. The potential benefit of a systems-based consideration of the concurrent multiple dynamic processes occurring upon co-dosing lipids and drugs to predict the impact of lipids on drug absorption and enable rational design of lipid-based delivery systems is presented. PMID:27520734

  5. Lipid-associated oral delivery: Mechanisms and analysis of oral absorption enhancement.

    PubMed

    Rezhdo, Oljora; Speciner, Lauren; Carrier, Rebecca

    2016-10-28

    The majority of newly discovered oral drugs are poorly water soluble, and co-administration with lipids has proven effective in significantly enhancing bioavailability of some compounds with low aqueous solubility. Yet, lipid-based delivery technologies have not been widely employed in commercial oral products. Lipids can impact drug transport and fate in the gastrointestinal (GI) tract through multiple mechanisms including enhancement of solubility and dissolution kinetics, enhancement of permeation through the intestinal mucosa, and triggering drug precipitation upon lipid emulsion depletion (e.g., by digestion). The effect of lipids on drug absorption is currently not quantitatively predictable, in part due to the multiple complex dynamic processes that can be impacted by lipids. Quantitative mechanistic analysis of the processes significant to lipid system function and overall impact on drug absorption can aid in the understanding of drug-lipid interactions in the GI tract and exploitation of such interactions to achieve optimal lipid-based drug delivery. In this review, we discuss the impact of co-delivered lipids and lipid digestion on drug dissolution, partitioning, and absorption in the context of the experimental tools and associated kinetic expressions used to study and model these processes. The potential benefit of a systems-based consideration of the concurrent multiple dynamic processes occurring upon co-dosing lipids and drugs to predict the impact of lipids on drug absorption and enable rational design of lipid-based delivery systems is presented. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. An Accurate Absorption-Based Net Primary Production Model for the Global Ocean

    NASA Astrophysics Data System (ADS)

    Silsbe, G.; Westberry, T. K.; Behrenfeld, M. J.; Halsey, K.; Milligan, A.

    2016-02-01

    As a vital living link in the global carbon cycle, understanding how net primary production (NPP) varies through space, time, and across climatic oscillations (e.g. ENSO) is a key objective in oceanographic research. The continual improvement of ocean observing satellites and data analytics now present greater opportunities for advanced understanding and characterization of the factors regulating NPP. In particular, the emergence of spectral inversion algorithms now permits accurate retrievals of the phytoplankton absorption coefficient (aΦ) from space. As NPP is the efficiency in which absorbed energy is converted into carbon biomass, aΦ measurements circumvents chlorophyll-based empirical approaches by permitting direct and accurate measurements of phytoplankton energy absorption. It has long been recognized, and perhaps underappreciated, that NPP and phytoplankton growth rates display muted variability when normalized to aΦ rather than chlorophyll. Here we present a novel absorption-based NPP model that parameterizes the underlying physiological mechanisms behind this muted variability, and apply this physiological model to the global ocean. Through a comparison against field data from the Hawaii and Bermuda Ocean Time Series, we demonstrate how this approach yields more accurate NPP measurements than other published NPP models. By normalizing NPP to satellite estimates of phytoplankton carbon biomass, this presentation also explores the seasonality of phytoplankton growth rates across several oceanic regions. Finally, we discuss how future advances in remote-sensing (e.g. hyperspectral satellites, LIDAR, autonomous profilers) can be exploited to further improve absorption-based NPP models.

  7. Influence of light absorption on relativistic self-focusing of Gaussian laser beam in cold quantum plasma

    NASA Astrophysics Data System (ADS)

    Patil, S. D.; Valkunde, A. T.; Vhanmore, B. D.; Urunkar, T. U.; Gavade, K. M.; Takale, M. V.

    2018-05-01

    When inter particle distance is comparable to the de Broglies wavelength of charged particles, quantum effects in plasmas are unavoidable. We have exploited an influence of light absorption on self-focusing of Gaussian laser beam in cold quantum plasma by considering relativistic nonlinearity. Nonlinear differential equation governing beam-width parameter has been established by using parabolic equation approach under paraxial and WKB approximations. The effect of light absorption on variation of beam-width parameter with dimensionless distance of propagation is presented graphically and discussed. It is found that light absorption plays vital role in weakening the relativistic self-focusing of laser beam during propagation in cold quantum plasma and gives reasonably interesting results.

  8. Systematic Exploitation of Multiple Receptor Conformations for Virtual Ligand Screening

    PubMed Central

    Bottegoni, Giovanni; Rocchia, Walter; Rueda, Manuel; Abagyan, Ruben; Cavalli, Andrea

    2011-01-01

    The role of virtual ligand screening in modern drug discovery is to mine large chemical collections and to prioritize for experimental testing a comparatively small and diverse set of compounds with expected activity against a target. Several studies have pointed out that the performance of virtual ligand screening can be improved by taking into account receptor flexibility. Here, we systematically assess how multiple crystallographic receptor conformations, a powerful way of discretely representing protein plasticity, can be exploited in screening protocols to separate binders from non-binders. Our analyses encompass 36 targets of pharmaceutical relevance and are based on actual molecules with reported activity against those targets. The results suggest that an ensemble receptor-based protocol displays a stronger discriminating power between active and inactive molecules as compared to its standard single rigid receptor counterpart. Moreover, such a protocol can be engineered not only to enrich a higher number of active compounds, but also to enhance their chemical diversity. Finally, some clear indications can be gathered on how to select a subset of receptor conformations that is most likely to provide the best performance in a real life scenario. PMID:21625529

  9. Exploiting Temporal Collateral Sensitivity in Tumor Clonal Evolution.

    PubMed

    Zhao, Boyang; Sedlak, Joseph C; Srinivas, Raja; Creixell, Pau; Pritchard, Justin R; Tidor, Bruce; Lauffenburger, Douglas A; Hemann, Michael T

    2016-03-24

    The prevailing approach to addressing secondary drug resistance in cancer focuses on treating the resistance mechanisms at relapse. However, the dynamic nature of clonal evolution, along with potential fitness costs and cost compensations, may present exploitable vulnerabilities-a notion that we term "temporal collateral sensitivity." Using a combined pharmacological screen and drug resistance selection approach in a murine model of Ph(+) acute lymphoblastic leukemia, we indeed find that temporal and/or persistent collateral sensitivity to non-classical BCR-ABL1 drugs arises in emergent tumor subpopulations during the evolution of resistance toward initial treatment with BCR-ABL1-targeted inhibitors. We determined the sensitization mechanism via genotypic, phenotypic, signaling, and binding measurements in combination with computational models and demonstrated significant overall survival extension in mice. Additional stochastic mathematical models and small-molecule screens extended our insights, indicating the value of focusing on evolutionary trajectories and pharmacological profiles to identify new strategies to treat dynamic tumor vulnerabilities. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. 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

  11. 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.

  12. Chitosan-based nanosystems and their exploited antimicrobial activity.

    PubMed

    Perinelli, Diego Romano; Fagioli, Laura; Campana, Raffaella; Lam, Jenny K W; Baffone, Wally; Palmieri, Giovanni Filippo; Casettari, Luca; Bonacucina, Giulia

    2018-05-30

    Chitosan is a biodegradable and biocompatible natural polysaccharide that has a wide range of applications in the field of pharmaceutics, biomedical, chemical, cosmetics, textile and food industry. One of the most interesting characteristics of chitosan is its antibacterial and antifungal activity, and together with its excellent safety profile in human, it has attracted considerable attention in various research disciplines. The antimicrobial activity of chitosan is dependent on a number of factors, including its molecular weight, degree of deacetylation, degree of substitution, physical form, as well as structural properties of the cell wall of the target microorganisms. While the sole use of chitosan may not be sufficient to produce an adequate antimicrobial effect to fulfil different purposes, the incorporation of this biopolymer with other active substances such as drugs, metals and natural compounds in nanosystems is a commonly employed strategy to enhance its antimicrobial potential. In this review, we aim to provide an overview on the different approaches that exploit the antimicrobial activity of chitosan-based nanosystems and their applications, and highlight the latest advances in this field. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Exploitation of vegetables and fruits through lactic acid fermentation.

    PubMed

    Di Cagno, Raffaella; Coda, Rossana; De Angelis, Maria; Gobbetti, Marco

    2013-02-01

    Lactic acid fermentation represents the easiest and the most suitable way for increasing the daily consumption of fresh-like vegetables and fruits. Literature data are accumulating, and this review aims at describing the main features of the lactic acid bacteria to be used for fermentation. Lactic acid bacteria are a small part of the autochthonous microbiota of vegetables and fruits. The diversity of the microbiota markedly depends on the intrinsic and extrinsic parameters of the plant matrix. Notwithstanding the reliable value of the spontaneous fermentation to stabilize and preserve raw vegetables and fruits, a number of factors are in favour of using selected starters. Two main options may be pursued for the controlled lactic acid fermentation of vegetables and fruits: the use of commercial/allochthonous and the use of autochthonous starters. Several evidences were described in favour of the use of selected autochthonous starters, which are tailored for the specific plant matrix. Pro-technological, sensory and nutritional criteria for selecting starters were reported as well as several functional properties, which were recently ascribed to autochthonous lactic acid bacteria. The main features of the protocols used for the manufacture of traditional, emerging and innovative fermented vegetables and fruits were reviewed. Tailored lactic acid bacteria starters completely exploit the potential of vegetables and fruits, which enhances the hygiene, sensory, nutritional and shelf life properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Solar system for exploitation of the whole collected energy

    NASA Astrophysics Data System (ADS)

    Ciamberlini, C.; Francini, F.; Longobardi, G.; Piattelli, M.; Sansoni, P.

    2003-09-01

    An innovative architecture for the exploitation of the whole collected solar energy is described. A sun pointing optical concentrator focuses the received energy, containing the part of the required solar spectrum, in a low loss optical fibre transmission line. The optical panel is small in size and able to follow the sun in order to collect the maximum of its energy. The support is flat, 5 mm thick and includes four optical concentrators. The efficiency of the optical system depends on the optical configuration and on the material utilised for the optical components. Single commercial connector to the fixed fibres connects the fibre optics' four free ends. The energy is therefore properly transported to any user's end with an easy installation. The system was experimented for lightening, during the day, dissipated in a dark load in order to produce heat in some equipment and for photovoltaic applications. The total efficiency of the system was between 68% and 72%. Once the solar energy reaches the end of the transmission line, it can be addressed to the required utilisation by means of an optical switch, which redirects the sunlight towards the desired applicator. This procedure allows utilising the 100% of the sun-collected energy. Since the size of the panel was small, it can be placed, on the roof, on the garden, on the window-sill, on the field and on all sides exposed to sunlight.

  15. Environmental Factors and Zoonotic Pathogen Ecology in Urban Exploiter Species.

    PubMed

    Rothenburger, Jamie L; Himsworth, Chelsea H; Nemeth, Nicole M; Pearl, David L; Jardine, Claire M

    2017-09-01

    Knowledge of pathogen ecology, including the impacts of environmental factors on pathogen and host dynamics, is essential for determining the risk that zoonotic pathogens pose to people. This review synthesizes the scientific literature on environmental factors that influence the ecology and epidemiology of zoonotic microparasites (bacteria, viruses and protozoa) in globally invasive urban exploiter wildlife species (i.e., rock doves [Columba livia domestica], European starlings [Sturnus vulgaris], house sparrows [Passer domesticus], Norway rats [Rattus norvegicus], black rats [R. rattus] and house mice [Mus musculus]). Pathogen ecology, including prevalence and pathogen characteristics, is influenced by geographical location, habitat, season and weather. The prevalence of zoonotic pathogens in mice and rats varies markedly over short geographical distances, but tends to be highest in ports, disadvantaged (e.g., low income) and residential areas. Future research should use epidemiological approaches, including random sampling and robust statistical analyses, to evaluate a range of biotic and abiotic environmental factors at spatial scales suitable for host home range sizes. Moving beyond descriptive studies to uncover the causal factors contributing to uneven pathogen distribution among wildlife hosts in urban environments may lead to targeted surveillance and intervention strategies. Application of this knowledge to urban maintenance and planning may reduce the potential impacts of urban wildlife-associated zoonotic diseases on people.

  16. Exploiting delayed transitions to sustain semiarid ecosystems after catastrophic shifts.

    PubMed

    Vidiella, Blai; Sardanyés, Josep; Solé, Ricard

    2018-06-01

    Semiarid ecosystems (including arid, semiarid and dry-subhumid ecosystems) span more than 40% of extant habitats and contain a similar percentage of the human population. Theoretical models and palaeoclimatic data predict a grim future, with rapid shifts towards a desert state, with accelerated diversity losses and ecological collapses. These shifts are a consequence of the special nonlinearities resulting from ecological facilitation. Here, we investigate a simple model of semiarid ecosystems identifying the so-called ghost, which appears after a catastrophic transition from a vegetated to a desert state once a critical rate of soil degradation is overcome. The ghost involves a slowdown of transients towards the desert state, making the ecosystem seem stable even though vegetation extinction is inevitable. We use this model to show how to exploit the ecological ghosts to avoid collapse. Doing so involves the restoration of small fractions of desert areas with vegetation capable of maintaining a stable community once the catastrophic shift condition has been achieved. This intervention method is successfully tested under the presence of demographic stochastic fluctuations. © 2018 The Author(s).

  17. On justifying the exploitation of animals in research.

    PubMed

    Sapontzis, S F

    1988-05-01

    In research employing animals we commonly do things to them which would be grossly immoral to do to humans. This paper discusses three possible justifications for so treating animals: (a) it is violating the autonomy of rational beings which makes actions immoral, and animals are not autonomous; (b) due to our participation in the human community, we have special obligations to humans that we do not have to animals; and (c) human life is morally more worthy than animal life. The conclusion of this discussion is that none of these three propositions justifies the routine sacrifice of animal interests for human benefit. Particular attention is paid to the idea that human life is morally more worthy than animal life, because I believe that to be the most common justification for our sacrifice of animal interests in research. The claim of greater worth is considered and criticized from both utilitarian and Kantian perspectives, and the inference from superior worth to being entitled to exploit one's inferiors is also criticized. The paper concludes by recommending a governing principle for research with animals which would bring that research into line with the rejection of hierarchical worldviews, social orders, and value systems which characterizes modern moral progress.

  18. 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

  19. Plant stress signalling: understanding and exploiting plant-plant interactions.

    PubMed

    Pickett, J A; Rasmussen, H B; Woodcock, C M; Matthes, M; Napier, J A

    2003-02-01

    When plants are attacked by insects, volatile chemical signals can be released, not only from the damaged parts, but also systemically from other parts of the plant and this continues after cessation of feeding by the insect. These signals are perceived by olfactory sensory mechanisms in both the herbivorous insects and their parasites. Molecular structures involved can be characterized by means of electrophysiological assays, using the insect sensory system linked to chemical analysis. Evidence is mounting that such signals can also affect neighbouring intact plants, which initiate defence by the induction of further signalling systems, such as those that increase parasitoid foraging. Furthermore, insect electrophysiology can be used in the identification of plant compounds having effects on the plants themselves. It has been found recently that certain plants can release stress signals even when undamaged, and that these can cause defence responses in intact plants. These discoveries provide the basis for new crop protection strategies, that are either delivered by genetic modification of plants or by conventionally produced plants to which the signal is externally applied. Delivery can also be made by means of mixed seed strategies in which the provoking and recipient plants are grown together. Related signalling discoveries within the rhizosphere seem set to extend these approaches into new ways of controlling weeds, by exploiting the elusive potential of allelopathy, but through signalling rather than by direct physiological effects.

  20. MAPI: towards the integrated exploitation of bioinformatics Web Services.

    PubMed

    Ramirez, Sergio; Karlsson, Johan; Trelles, Oswaldo

    2011-10-27

    Bioinformatics is commonly featured as a well assorted list of available web resources. Although diversity of services is positive in general, the proliferation of tools, their dispersion and heterogeneity complicate the integrated exploitation of such data processing capacity. To facilitate the construction of software clients and make integrated use of this variety of tools, we present a modular programmatic application interface (MAPI) that provides the necessary functionality for uniform representation of Web Services metadata descriptors including their management and invocation protocols of the services which they represent. This document describes the main functionality of the framework and how it can be used to facilitate the deployment of new software under a unified structure of bioinformatics Web Services. A notable feature of MAPI is the modular organization of the functionality into different modules associated with specific tasks. This means that only the modules needed for the client have to be installed, and that the module functionality can be extended without the need for re-writing the software client. The potential utility and versatility of the software library has been demonstrated by the implementation of several currently available clients that cover different aspects of integrated data processing, ranging from service discovery to service invocation with advanced features such as workflows composition and asynchronous services calls to multiple types of Web Services including those registered in repositories (e.g. GRID-based, SOAP, BioMOBY, R-bioconductor, and others).

  1. Commercial imagery archive, management, exploitation, and distribution project development

    NASA Astrophysics Data System (ADS)

    Hollinger, Bruce; Sakkas, Alysa

    1999-10-01

    The Lockheed Martin (LM) team had garnered over a decade of operational experience on the U.S. Government's IDEX II (Imagery Dissemination and Exploitation) system. Recently, it set out to create a new commercial product to serve the needs of large-scale imagery archiving and analysis markets worldwide. LM decided to provide a turnkey commercial solution to receive, store, retrieve, process, analyze and disseminate in 'push' or 'pull' modes imagery, data and data products using a variety of sources and formats. LM selected 'best of breed' hardware and software components and adapted and developed its own algorithms to provide added functionality not commercially available elsewhere. The resultant product, Intelligent Library System (ILS)TM, satisfies requirements for (1) a potentially unbounded, data archive (5000 TB range) (2) automated workflow management for increased user productivity; (3) automatic tracking and management of files stored on shelves; (4) ability to ingest, process and disseminate data volumes with bandwidths ranging up to multi- gigabit per second; (5) access through a thin client-to-server network environment; (6) multiple interactive users needing retrieval of files in seconds from both archived images or in real time, and (7) scalability that maintains information throughput performance as the size of the digital library grows.

  2. Commercial imagery archive, management, exploitation, and distribution product development

    NASA Astrophysics Data System (ADS)

    Hollinger, Bruce; Sakkas, Alysa

    1999-12-01

    The Lockheed Martin (LM) team had garnered over a decade of operational experience on the U.S. Government's IDEX II (Imagery Dissemination and Exploitation) system. Recently, it set out to create a new commercial product to serve the needs of large-scale imagery archiving and analysis markets worldwide. LM decided to provide a turnkey commercial solution to receive, store, retrieve, process, analyze and disseminate in 'push' or 'pull' modes imagery, data and data products using a variety of sources and formats. LM selected 'best of breed' hardware and software components and adapted and developed its own algorithms to provide added functionality not commercially available elsewhere. The resultant product, Intelligent Library System (ILS)TM, satisfies requirements for (a) a potentially unbounded, data archive (5000 TB range) (b) automated workflow management for increased user productivity; (c) automatic tracking and management of files stored on shelves; (d) ability to ingest, process and disseminate data volumes with bandwidths ranging up to multi- gigabit per second; (e) access through a thin client-to-server network environment; (f) multiple interactive users needing retrieval of files in seconds from both archived images or in real time, and (g) scalability that maintains information throughput performance as the size of the digital library grows.

  3. Exploiting Synthetic Aperture Radar data to map and observe landslides

    NASA Astrophysics Data System (ADS)

    Bekaert, D. P.; Agram, P. S.; Fattahi, H.; Kirschbaum, D.; Amatya, P. M.; Stanley, T.

    2017-12-01

    Synthetic Aperture Radar instruments onboard satellites or airborne platforms are a powerful means to study landslides. How to best exploit the data and which techniques to apply strongly depend on the region of study and the landslide type which occurs. The amount of vegetation, snowfall, and steepness of the terrain, as well the shadowing effects of the mountain will determine if SAR is suitable to map a given landslide. Fast moving landslides occurring over a large area (e.g. >100 m) could benefit from pixel or feature tracking, while for slower moving landslides Interferometric SAR could be a more favorable approach. However, neither of those methods would work for critical landslide failures which do not preserve surface features. This type of slides would benefit from a change detection approach. Here we look at these three different cases and utilize Sentinel-1 space-borne SAR data and state-of-the-art processing techniques to map multiple landslides along the California State Route 1 and the Trishuli highway in the Langtang valley of Nepal. Our findings correlate with existing landslide catalogues and also identify landslides in regions earlier mapped to be dormant.

  4. Exploiting dimensionality and defect mitigation to create tunable microwave dielectrics

    SciTech Connect

    Lee, Che-Hui; Orloff, Nathan; Birol, Turan

    2013-01-01

    The miniaturization and integration of frequency-agile microwave circuits tunable filters, resonators, phase shifters and more with microelectronics offers tantalizing device possibilities, yet requires thin films whose dielectric constant at GHz frequencies can be tuned by applying a quasi-static electric field . Appropriate systems, e.g., BaxSr1 xTiO3, have a paraelectric-to-ferroelectric transition just below ambient temperature, providing high tunability1 . Unfortunately such films suffer significant losses arising from defects. Recognizing that progress is stymied by dielectric loss, we start with a system with exceptionally low loss Srn+1TinO3n+1 phases , where (SrO)2 crystallographic shear , planes provide an alternative to point defect formationmore » for accommodating non-stoichiometry , . Here, we report the experimental realization of a highly tunable ground state arising from the emergence of a local ferroelectric instability in biaxially strained Srn+1TinO3n+1 phases with n 3 at frequencies up to 120 GHz. In contrast to traditional methods of modifying ferroelectrics doping or strain in this rather unique system increasing the separation between the (SrO)2 planes bolsters the local ferroelectric instability. This new control parameter, n, can be exploited to achieve a figure of merit at room temperature that rivals all known tunable microwave dielectrics.« less

  5. Improving industrial yeast strains: exploiting natural and artificial diversity.

    PubMed

    Steensels, Jan; Snoek, Tim; Meersman, Esther; Picca Nicolino, Martina; Voordeckers, Karin; Verstrepen, Kevin J

    2014-09-01

    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. © 2014 The Authors. FEMS Microbiology Reviews published by John Wiley & Sons Ltd on behalf of Federation of European Microbiological Societies.

  6. 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

  7. 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.

  8. An objective function exploiting suboptimal solutions in metabolic networks

    PubMed Central

    2013-01-01

    Background Flux Balance Analysis is a theoretically elegant, computationally efficient, genome-scale approach to predicting biochemical reaction fluxes. Yet FBA models exhibit persistent mathematical degeneracy that generally limits their predictive power. Results We propose a novel objective function for cellular metabolism that accounts for and exploits degeneracy in the metabolic network to improve flux predictions. In our model, regulation drives metabolism toward a region of flux space that allows nearly optimal growth. Metabolic mutants deviate minimally from this region, a function represented mathematically as a convex cone. Near-optimal flux configurations within this region are considered equally plausible and not subject to further optimizing regulation. Consistent with relaxed regulation near optimality, we find that the size of the near-optimal region predicts flux variability under experimental perturbation. Conclusion Accounting for suboptimal solutions can improve the predictive power of metabolic FBA models. Because fluctuations of enzyme and metabolite levels are inevitable, tolerance for suboptimality may support a functionally robust metabolic network. PMID:24088221

  9. Exploiting temporal collateral sensitivity in tumor clonal evolution

    PubMed Central

    Zhao, Boyang; Sedlak, Joseph C.; Srinivas, Raja; Creixell, Pau; Pritchard, Justin R.; Tidor, Bruce; Lauffenburger, Douglas A.; Hemann, Michael T.

    2016-01-01

    SUMMARY The prevailing approach to addressing secondary drug resistance in cancer focuses on treating the resistance mechanisms at relapse. However, the dynamic nature of clonal evolution, along with potential fitness costs and cost compensations, may present exploitable vulnerabilities; a notion that we term ‘temporal collateral sensitivity’. Using a combined pharmacological screen and drug resistance selection approach in a murine model of Ph+ acute lymphoblastic leukemia, we indeed find that temporal and/or persistent collateral sensitivity to non-classical BCR-ABL1 drugs arises in emergent tumor subpopulations during the evolution of resistance toward initial treatment with BCR-ABL1 targeted inhibitors. We determined the sensitization mechanism via genotypic, phenotypic, signaling, and binding measurements in combination with computational models, and demonstrated significant overall survival extension in mice. Additional stochastic mathematical models and small molecule screens extended our insights, indicating the value of focusing on evolutionary trajectories and pharmacological profiles to identify new strategies to treat dynamic tumor vulnerabilities. PMID:26924578

  10. Exploiting dimensionality and defect mitigation to create tunable microwave dielectrics

    NASA Astrophysics Data System (ADS)

    Lee, Che-Hui; Orloff, Nathan D.; Birol, Turan; Zhu, Ye; Goian, Veronica; Rocas, Eduard; Haislmaier, Ryan; Vlahos, Eftihia; Mundy, Julia A.; Kourkoutis, Lena F.; Nie, Yuefeng; Biegalski, Michael D.; Zhang, Jingshu; Bernhagen, Margitta; Benedek, Nicole A.; Kim, Yongsam; Brock, Joel D.; Uecker, Reinhard; Xi, X. X.; Gopalan, Venkatraman; Nuzhnyy, Dmitry; Kamba, Stanislav; Muller, David A.; Takeuchi, Ichiro; Booth, James C.; Fennie, Craig J.; Schlom, Darrell G.

    2013-10-01

    The miniaturization and integration of frequency-agile microwave circuits--relevant to electronically tunable filters, antennas, resonators and phase shifters--with microelectronics offers tantalizing device possibilities, yet requires thin films whose dielectric constant at gigahertz frequencies can be tuned by applying a quasi-static electric field. Appropriate systems such as BaxSr1-xTiO3 have a paraelectric-ferroelectric transition just below ambient temperature, providing high tunability. Unfortunately, such films suffer significant losses arising from defects. Recognizing that progress is stymied by dielectric loss, we start with a system with exceptionally low loss--Srn+1TinO3n+1 phases--in which (SrO)2 crystallographic shear planes provide an alternative to the formation of point defects for accommodating non-stoichiometry. Here we report the experimental realization of a highly tunable ground state arising from the emergence of a local ferroelectric instability in biaxially strained Srn+1TinO3n+1 phases with n>=3 at frequencies up to 125GHz. In contrast to traditional methods of modifying ferroelectrics--doping or strain--in this unique system an increase in the separation between the (SrO)2 planes, which can be achieved by changing n, bolsters the local ferroelectric instability. This new control parameter, n, can be exploited to achieve a figure of merit at room temperature that rivals all known tunable microwave dielectrics.

  11. Fit for purpose quality management system for military forensic exploitation.

    PubMed

    Wilson, Lauren Elizabeth; Gahan, Michelle Elizabeth; Robertson, James; Lennard, Chris

    2018-03-01

    In a previous publication we described a systems approach to forensic science applied in the military domain. The forensic science 'system of systems' describes forensic science as a sub-system in the larger criminal justice, law enforcement, intelligence, and military systems, with quality management being an important supporting system. Quality management systems help to ensure that organisations achieve their objective and continually improve their capability. Components of forensic science quality management systems can include standardisation of processes, accreditation of facilities to national/international standards, and certification of personnel. A fit for purpose quality management system should be balanced to allow organisations to meet objectives, provide continuous improvement; mitigate risk; and impart a positive quality culture. Considerable attention over the last decades has been given to the need for forensic science quality management systems to meet criminal justice and law enforcement objectives. More recently, the need for the forensic quality management systems to meet forensic intelligence objectives has been considered. This paper, for the first time, discusses the need for a fit for purpose quality management system for military forensic exploitation. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

  12. Exploiting Concurrent Wake-Up Transmissions Using Beat Frequencies

    PubMed Central

    2017-01-01

    Wake-up receivers are the natural choice for wireless sensor networks because of their ultra-low power consumption and their ability to provide communications on demand. A downside of ultra-low power wake-up receivers is their low sensitivity caused by the passive demodulation of the carrier signal. In this article, we present a novel communication scheme by exploiting purposefully-interfering out-of-tune signals of two or more wireless sensor nodes, which produce the wake-up signal as the beat frequency of superposed carriers. Additionally, we introduce a communication algorithm and a flooding protocol based on this approach. Our experiments show that our approach increases the received signal strength up to 3 dB, improving communication robustness and reliability. Furthermore, we demonstrate the feasibility of our newly-developed protocols by means of an outdoor experiment and an indoor setup consisting of several nodes. The flooding algorithm achieves almost a 100% wake-up rate in less than 20 ms. PMID:28933749

  13. Exploiting Concurrent Wake-Up Transmissions Using Beat Frequencies.

    PubMed

    Kumberg, Timo; Schindelhauer, Christian; Reindl, Leonhard

    2017-07-26

    Wake-up receivers are the natural choice for wireless sensor networks because of their ultra-low power consumption and their ability to provide communications on demand. A downside of ultra-low power wake-up receivers is their low sensitivity caused by the passive demodulation of the carrier signal. In this article, we present a novel communication scheme by exploiting purposefully-interfering out-of-tune signals of two or more wireless sensor nodes, which produce the wake-up signal as the beat frequency of superposed carriers. Additionally, we introduce a communication algorithm and a flooding protocol based on this approach. Our experiments show that our approach increases the received signal strength up to 3 dB, improving communication robustness and reliability. Furthermore, we demonstrate the feasibility of our newly-developed protocols by means of an outdoor experiment and an indoor setup consisting of several nodes. The flooding algorithm achieves almost a 100% wake-up rate in less than 20 ms.

  14. Exploitation of high resolution beam spectroscopy diagnostics on MAST

    NASA Astrophysics Data System (ADS)

    Michael, Clive; Debock, Maarten; Conway, Neil; Akers, Rob; Appel, Lynton; Field, Anthony; Walsh, Mike; Wisse, Marco

    2009-11-01

    Recent developments in beam spectroscopy on MAST, including CXRS, MSE and a pilot FIDA system have revealed new information about phenomena such as ITBs, MHD instabilities, transport and fast particle physics. For example, ITBs in the ion temperature and toroidal rotation have been observed with the 64ch CXRS system, while reverse-shear q profiles have been observed with the recently commissioned 35ch MSE system. Thus, the synergy of these diagnostics helps us to understand, among other things, the role of magnetic and rotational shear on ITBs. MSE measurements have also helped to understand MHD phenomena such as locked modes (characterized by changes in toroidal momentum, revealed by CXRS), sawteeth, and internal reconnection events. Finally, the temporal/spatial resolution and SNR of the MSE system have been exploited. Interesting results include the detection of low frequency (˜2kHz) magnetic field fluctuations, characterization of the radial structure of higher frequency (<100kHz) broadband and coherent density (BES) fluctuations, and the identification of short scale length features (˜1.8cm) in the current profile near the edge pedestal.

  15. 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.

  16. The Exploitation of Low-Energy Electrons in Cancer Treatment.

    PubMed

    Rezaee, Mohammad; Hill, Richard P; Jaffray, David A

    2017-08-01

    Given the distinct characteristics of low-energy electrons (LEEs), particularly at energies less than 30 eV, they can be applied to a wide range of therapeutic modalities to improve cancer treatment. LEEs have been shown to efficiently produce complex molecular damage resulting in substantial cellular toxicities. Since LEEs are produced in copious amounts from high-energy radiation beam, including photons, protons and ions; the control of LEE distribution can potentially enhance the therapeutic radio of such beams. LEEs can play a substantial role in the synergistic effect between radiation and chemotherapy, particularly halogenated and platinum-based anticancer drugs. Radiosensitizing entities containing atoms of high atomic number such as gold nanoparticles can be a source of LEE production if high-energy radiation interacts with them. This can provide a high local density of LEEs in a cell and produce cellular toxicity. Auger-electron-emitting radionuclides also create a high number of LEEs in each decay, which can induce lethal damage in a cell. Exploitation of LEEs in cancer treatment, however, faces a few challenges, such as dosimetry of LEEs and selective delivery of radiosensitizing and chemotherapeutic molecules close to cellular targets. This review first discusses the rationale for utilizing LEEs in cancer treatment by explaining their mechanism of action, describes theoretical and experimental studies at the molecular and cellular levels, then discusses strategies for achieving modification of the distribution and effectiveness of LEEs in cancerous tissue and their associated clinical benefit.

  17. 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.

  18. 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.

  19. 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.

  20. SASS: A symmetry adapted stochastic search algorithm exploiting site symmetry

    NASA Astrophysics Data System (ADS)

    Wheeler, Steven E.; Schleyer, Paul v. R.; Schaefer, Henry F.

    2007-03-01

    A simple symmetry adapted search algorithm (SASS) exploiting point group symmetry increases the efficiency of systematic explorations of complex quantum mechanical potential energy surfaces. In contrast to previously described stochastic approaches, which do not employ symmetry, candidate structures are generated within simple point groups, such as C2, Cs, and C2v. This facilitates efficient sampling of the 3N-6 Pople's dimensional configuration space and increases the speed and effectiveness of quantum chemical geometry optimizations. Pople's concept of framework groups [J. Am. Chem. Soc. 102, 4615 (1980)] is used to partition the configuration space into structures spanning all possible distributions of sets of symmetry equivalent atoms. This provides an efficient means of computing all structures of a given symmetry with minimum redundancy. This approach also is advantageous for generating initial structures for global optimizations via genetic algorithm and other stochastic global search techniques. Application of the SASS method is illustrated by locating 14 low-lying stationary points on the cc-pwCVDZ ROCCSD(T) potential energy surface of Li5H2. The global minimum structure is identified, along with many unique, nonintuitive, energetically favorable isomers.

  1. New strategies in glioblastoma: exploiting the new biology.

    PubMed

    Fine, Howard A

    2015-05-01

    Glioblastoma is one of the deadliest human cancers. There have been few significant therapeutic advances in the field over the past two decades, with median survival of only about 15 months despite aggressive neurosurgery, radiotherapy, and chemotherapy. Nevertheless, the past 5 years has seen an explosion in our understanding of the genetic and molecular underpinnings of these tumors, leading to renewed optimism about potential new therapeutic approaches. Several of the most promising new approaches include oncogenic signal transduction inhibition, angiogenesis inhibition, targeting canonical stem cell pathways in glioblastoma stem cells, and immunotherapy. As promising as many of these approaches appear, they have not had an impact yet on the natural history of the disease or on patient long-term outcomes. Nevertheless, it is hoped that with time such approaches will lead to more effective treatments, but issues such as the unique biology and anatomy of the central nervous system, impaired drug delivery, poor preclinical models with resultant nonpredictive preclinical screening, and poor clinical trial design potentially impede the rapid development of such new therapies. In this article, we review the excitement and challenges that face the development of effective new treatments that exploit this new biology. ©2015 American Association for Cancer Research.

  2. Sampling strategies exploiting multi-pumping flow systems.

    PubMed

    Prior, João A V; Santos, João L M; Lima, José L F C

    2003-04-01

    In this work new strategies were exploited to implement multi-pumping flow systems relying on the utilisation of multiple devices that act simultaneously as sample-insertion, reagent-introduction, and solution-propelling units. The solenoid micro-pumps that were initially used as the only active elements of multi-pumping systems, and which were able to produce pulses of 3 to 25 microL, were replaced by syringe pumps with the aim of producing pulses between 1 and 4 microL. The performance of the developed flow system was assessed by using distinct sample-insertion strategies like single sample volume, merging zones, and binary sampling in the spectrophotometric determination of isoniazid in pharmaceutical formulations upon reaction with 1,2-naphthoquinone-4-sulfonate, in alkaline medium. The results obtained showed that enhanced sample/reagent mixing could be obtained with binary sampling and by using a 1 microL per step pump, even in limited dispersion conditions. Moreover, syringe pumps produce very reproducible flowing streams and are easily manipulated and controlled by a computer program, which is greatly simplified since they are the only active manifold component. Linear calibration plots up to 18.0 microg mL(-1), with a relative standard deviation of less than 1.48% (n=10) and a throughput of about 20 samples per hour, were obtained.

  3. Synergistic approach of asteroid exploitation and planetary protection

    NASA Astrophysics Data System (ADS)

    Sanchez, J. P.; McInnes, C. R.

    2012-02-01

    The asteroid and cometary impact hazard has long been recognised as an important issue requiring risk assessment and contingency planning. At the same time asteroids have also been acknowledged as possible sources of raw materials for future large-scale space engineering ventures. This paper explores possible synergies between these two apparently opposed views; planetary protection and space resource exploitation. In particular, the paper assumes a 5 tonne low-thrust spacecraft as a baseline for asteroid deflection and capture (or resource transport) missions. The system is assumed to land on the asteroid and provide a continuous thrust able to modify the orbit of the asteroid according to the mission objective. The paper analyses the capability of such a near-term system to provide both planetary protection and asteroid resources to Earth. Results show that a 5 tonne spacecraft could provide a high level of protection for modest impact hazards: airburst and local damage events (caused by 15-170 m diameter objects). At the same time, the same spacecraft could also be used to transport to bound Earth orbits significant quantities of material through judicious use of orbital dynamics and passively safe aero-capture manoeuvres or low energy ballistic capture. As will be shown, a 5 tonne low-thrust spacecraft could potentially transport between 12 and 350 times its own mass of asteroid resources by means of ballistic capture or aero-capture trajectories that pose very low dynamical pressures on the object.

  4. 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.

  5. 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.

  6. Exploiting parallel R in the cloud with SPRINT.

    PubMed

    Piotrowski, M; McGilvary, G A; Sloan, T M; Mewissen, M; Lloyd, A D; Forster, T; Mitchell, L; Ghazal, P; Hill, J

    2013-01-01

    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. 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. 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. It is possible to obtain good, scalable performance but the level of improvement is dependent upon the nature of the algorithm. Resource underutilization can further improve the time to result. End-user's location impacts on costs due to factors such as local taxation. 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.

  7. Joint reconstruction of PET-MRI by exploiting structural similarity

    NASA Astrophysics Data System (ADS)

    Ehrhardt, Matthias J.; Thielemans, Kris; Pizarro, Luis; Atkinson, David; Ourselin, Sébastien; Hutton, Brian F.; Arridge, Simon R.

    2015-01-01

    Recent advances in technology have enabled the combination of positron emission tomography (PET) with magnetic resonance imaging (MRI). These PET-MRI scanners simultaneously acquire functional PET and anatomical or functional MRI data. As function and anatomy are not independent of one another the images to be reconstructed are likely to have shared structures. We aim to exploit this inherent structural similarity by reconstructing from both modalities in a joint reconstruction framework. The structural similarity between two modalities can be modelled in two different ways: edges are more likely to be at similar positions and/or to have similar orientations. We analyse the diffusion process generated by minimizing priors that encapsulate these different models. It turns out that the class of parallel level set priors always corresponds to anisotropic diffusion which is sometimes forward and sometimes backward diffusion. We perform numerical experiments where we jointly reconstruct from blurred Radon data with Poisson noise (PET) and under-sampled Fourier data with Gaussian noise (MRI). Our results show that both modalities benefit from each other in areas of shared edge information. The joint reconstructions have less artefacts and sharper edges compared to separate reconstructions and the ℓ2-error can be reduced in all of the considered cases of under-sampling.

  8. Thermal exploitation of wastes with lignite for energy production.

    PubMed

    Grammelis, Panagiotis; Kakaras, Emmanuel; Skodras, George

    2003-11-01

    The thermal exploitation of wastewood with Greek lignite was investigated by performing tests in a laboratory-scale fluidized bed reactor, a 1-MW(th) semi-industrial circulating fluidized bed combustor, and an industrial boiler. Blends of natural wood, demolition wood, railroad sleepers, medium-density fiberboard residues, and power poles with lignite were used, and the co-combustion efficiency and the effect of wastewood addition on the emitted pollutants were investigated. Carbon monoxide, sulfur dioxide, and oxides of nitrogen emissions were continuously monitored, and, during the industrial-scale tests, the toxic emissions (polychlorinated dibenzodioxins and dibenzofurans and heavy metals) were determined. Ash samples were analyzed for heavy metals in an inductively coupled plasma-atomic emission spectroscopy spectrophotometer. Problems were observed during the preparation of wastewood, because species embedded with different compounds, such as railway sleepers and demolition wood, were not easily treated. All wastewood blends were proven good fuels; co-combustion proceeded smoothly and homogeneous temperature and pressure profiles were obtained. Although some fluctuations were observed, low emissions of gaseous pollutants were obtained for all fuel blends. The metal element emissions (in the flue gases and the solid residues) were lower than the legislative limits. Therefore, wastewood co-combustion with lignite can be realized, provided that the fuel handling and preparation can be practically performed in large-scale installations.

  9. Induced Transparency and Absorption in Coupled Microresonators

    NASA Technical Reports Server (NTRS)

    Smith, David D.; Chang, Hongrok

    2004-01-01

    We review the conditions for the occurrence of coherence phenomena in passive coupled optical microresonators. We derive the effective steady-state response and determine conditions for induced transparency and absorption in these systems.

  10. Detection of bacterial growth by gas absorption.

    PubMed

    Waters, J R

    1992-05-01

    When 24 different aerobic organisms were grown in a shaken culture, all were found to first absorb gas from the headspace. In a rudimentary medium, such as tryptic soy broth, 16 of the 24 organisms did not produce gas following the initial gas absorption. We have developed a simple, noninvasive method for detecting both gas absorption and production in multiple culture vials. The time to positivity was compared with that obtained by the BACTEC 460 blood culture system. For nearly all of these organisms, there was no difference. For some of those organisms that did not produce gas, e.g. Staphylococcus epidermidis, Moraxella osloensis, and Neisseria meningitidis, detection by gas absorption was a few hours faster. Gas absorption appears to be a promising technique for a new automated blood culture system because of its simplicity and because medium without special additives can be used to detect organisms that do not produce gas.

  11. Insulin analogues with improved absorption characteristics.

    PubMed

    Brange, J; Hansen, J F; Langkjaer, L; Markussen, J; Ribel, U; Sørensen, A R

    1992-01-01

    The insulin preparations available today are not ideal for therapy as s.c. injection does not provide a physiological insulin profile. With the aim to improve the absorption properties recombinant DNA technology has been utilized to design novel insulin molecules with changed physico-chemical characteristics and hence altered subcutaneous absorption kinetics. Soluble, long-acting human insulin analogues in which the isoelectric point has been increased from 5.4 to approx. 7 are absorbed very slowly, providing a more constant basal insulin delivery with lower day-to-day variation than present protracted preparations. In addition they have better storage stability. Rapid-acting human insulin analogues with largely reduced self-association are absorbed substantially faster from subcutaneous tissue than current regular insulin and thus are better suited for bolus injection. The absorption kinetics of these analogues have been able to explain the mechanism behind the dose effect on insulin absorption rate.

  12. Solar flare induced cosmic noise absorption

    NASA Astrophysics Data System (ADS)

    Ogunmodimu, Olugbenga; Honary, Farideh; Rogers, Neil; Falayi, E. O.; Bolaji, O. S.

    2018-06-01

    Solar flare events are a major observing emphasis for space weather because they affect the ionosphere and can eject high-energy particles that can adversely affect Earth's technologies. In this study we model 38.2 MHz cosmic noise absorption (CNA) by utilising measurements from the Imaging Riometer for Ionospheric Studies (IRIS) at Kilpisjärvi, Finland obtained during solar cycle 23 (1996-2009). We utilised X-ray archive for the same period from the Geostationary Operational Environmental Satellite (GOES) to study solar flare induced cosmic noise absorption. We identified the threshold of flare (M4 class) that could bear significant influence on CNA. Through epoch analysis, we show the magnitude of absorption that each class of flare could produce. Using the parameters of flare and absorption we present a model that could provide the basis for nowcast of CNA induced by M and X-class solar flares.

  13. The economics of solar powered absorption cooling

    NASA Technical Reports Server (NTRS)

    Bartlett, J. C.

    1978-01-01

    Analytic procedure evaluates cost of combining absorption-cycle chiller with solar-energy system in residential or commercial application. Procedure assumes that solar-energy system already exists to heat building and that cooling system must be added. Decision is whether to cool building with conventional vapor-compression-cycle chiller or to use solar-energy system to provide heat input to absorption chiller.

  14. Seasonal Solar Thermal Absorption Energy Storage Development.

    PubMed

    Daguenet-Frick, Xavier; Gantenbein, Paul; Rommel, Mathias; Fumey, Benjamin; Weber, Robert; Gooneseker, Kanishka; Williamson, Tommy

    2015-01-01

    This article describes a thermochemical seasonal storage with emphasis on the development of a reaction zone for an absorption/desorption unit. The heat and mass exchanges are modelled and the design of a suitable reaction zone is explained. A tube bundle concept is retained for the heat and mass exchangers and the units are manufactured and commissioned. Furthermore, experimental results of both absorption and desorption processes are presented and the exchanged power is compared to the results of the simulations.

  15. Morphology of Southern Hemisphere Riometer Auroral Absorption

    DTIC Science & Technology

    2006-06-01

    Departamento de Geofísica Universidad de Concepción, Concepción CHILE foppiano@udec.cl ABSTRACT A morphology of riometer auroral absorption is...PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Departamento de Geofísica Universidad de ...range of frequencies used an inverse -square frequency dependence approximately holds. Morphology of Southern Hemisphere Riometer Auroral Absorption

  16. Absorption and emission spectroscopy of individual semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    McDonald, Matthew P.

    The advent of controllable synthetic methods for the production of semiconductor nanostructures has led to their use in a host of applications, including light-emitting diodes, field effect transistors, sensors, and even television displays. This is, in part, due to the size, shape, and morphologically dependent optical and electrical properties that make this class of materials extremely customizable; wire-, rod- and sphere-shaped nanocrystals are readily synthesized through common wet chemical methods. Most notably, confining the physical dimension of the nanostructure to a size below its Bohr radius (aB) results in quantum confinement effects that increase its optical energy gap. Not only the size, but the shape of a particle can be exploited to tailor its optical and electrical properties. For example, confined CdSe quantum dots (QDs) and nanowires (NWs) of equivalent diameter possess significantly different optical gaps. This phenomenon has been ascribed to electrostatic contributions arising from dielectric screening effects that are more pronounced in an elongated (wire-like) morphology. Semiconducting nanostructures have thus received significant attention over the past two decades. However, surprisingly little work has been done to elucidate their basic photophysics on a single particle basis. What has been done has generally been accomplished through emission-based measurements, and thus does not fully capture the full breadth of these intriguing systems. What is therefore needed then are absorption-based studies that probe the size and shape dependent evolution of nanostructure photophysics. This thesis summarizes the single particle absorption spectroscopy that we have carried out to fill this knowledge gap. Specifically, the diameter-dependent progression of one-dimensional (1D) excitonic states in CdSe NWs has been revealed. This is followed by a study that focuses on the polarization selection rules of 1D excitons within single CdSe NWs. Finally

  17. Absorption Spectra of Gold Nanoparticle Suspensions

    NASA Astrophysics Data System (ADS)

    Anan'eva, M. V.; Nurmukhametov, D. R.; Zverev, A. S.; Nelyubina, N. V.; Zvekov, A. A.; Russakov, D. M.; Kalenskii, A. V.; Eremenko, A. N.

    2018-02-01

    Three gold nanoparticle suspensions are obtained, and mean radii in distributions - (6.1 ± 0.2), (11.9 ± 0.3), and (17.3 ± 0.7) nm - are determined by the transmission electron microscopy method. The optical absorption spectra of suspensions are obtained and studied. Calculation of spectral dependences of the absorption index of suspensions at values of the gold complex refractive index taken from the literature showed a significant deviation of experimental and calculated data in the region of 450-800 nm. Spectral dependences of the absorption of suspensions are simulated within the framework of the Mie-Drude theory taking into account the interband absorption in the form of an additional term in the imaginary part of the dielectric permittivity of the Gaussian type. It is shown that to quantify the spectral dependences in the region of the plasmon absorption band of nanoparticles, correction of the parameters of the interband absorption is necessary in addition to the increase of the relaxation parameter of the Drude theory. Spectral dependences of the dielectric permittivity of gold in nanodimensional state are refined from the solution of the inverse problem. The results of the present work are important for predicting the special features of operation of photonic devices and optical detonators based on gold nanoparticles.

  18. A search for intervening HI absorption

    NASA Astrophysics Data System (ADS)

    Reeves, Sarah N.; Sadler, Elaine M.; Allison, James R.; Koribalski, Baerbel S.; Curran, Stephen J.

    2013-03-01

    HI absorption-line studies provide a unique probe of the gas distribution and kinematics in galaxies well beyond the local universe (z ≳ 0.3). HI absorption-line surveys with next-generation radio telescopes will provide the first large-scale studies of HI in a redshift regime which is poorly understood. However, we currently lack the understanding to infer galaxy properties from absorption-line observations alone. To address this issue, we are conducting a search for intervening HI absorption in a sample of 20 nearby galaxies. Our aim is to investigate how the detection rate varies with distance from the galaxy. We target sight-lines to bright continuum sources, which intercept known gas-rich galaxies, selected from the HIPASS Bright Galaxy Catalogue (Koribalski et al. 2004). In our pilot sample, six galaxies with impact parameters < 20 kpc, we do not detect any absorption lines - although all are detected in 21cm emission. This indicates that an absorption non-detection cannot simply be interpreted as an absence of neutral gas - see Fig. 1. Our detection rate is low compared to previous surveys e.g. Gupta et al. (2010). This is, at least partially, due to the high resolution of the observations reducing the flux of the background source, which will also be an issue in future surveys, such as ASKAP-FLASH.

  19. Spectral Absorption Properties of Atmospheric Aerosols

    NASA Technical Reports Server (NTRS)

    Bergstrom, R. W.; Pilewskie, P.; Russell, P. B.; Redemann, J.; Bond, T. C.; Quinn, P. K.; Sierau, B.

    2007-01-01

    We have determined the solar spectral absorption optical depth of atmospheric aerosols for specific case studies during several field programs (three cases have been reported previously; two are new results). We combined airborne measurements of the solar net radiant flux density and the aerosol optical depth with a detailed radiative transfer model for all but one of the cases. The field programs (SAFARI 2000, ACE Asia, PRIDE, TARFOX, INTEX-A) contained aerosols representing the major absorbing aerosol types: pollution, biomass burning, desert dust and mixtures. In all cases the spectral absorption optical depth decreases with wavelength and can be approximated with a power-law wavelength dependence (Absorption Angstrom Exponent or AAE). We compare our results with other recent spectral absorption measurements and attempt to briefly summarize the state of knowledge of aerosol absorption spectra in the atmosphere. We discuss the limitations in using the AAE for calculating the solar absorption. We also discuss the resulting spectral single scattering albedo for these cases.

  20. High temperature measurement of water vapor absorption

    NASA Technical Reports Server (NTRS)

    Keefer, Dennis; Lewis, J. W. L.; Eskridge, Richard

    1985-01-01

    An investigation was undertaken to measure the absorption coefficient, at a wavelength of 10.6 microns, for mixtures of water vapor and a diluent gas at high temperature and pressure. The experimental concept was to create the desired conditions of temperature and pressure in a laser absorption wave, similar to that which would be created in a laser propulsion system. A simplified numerical model was developed to predict the characteristics of the absorption wave and to estimate the laser intensity threshold for initiation. A non-intrusive method for temperature measurement utilizing optical laser-beam deflection (OLD) and optical spark breakdown produced by an excimer laser, was thoroughly investigated and found suitable for the non-equilibrium conditions expected in the wave. Experiments were performed to verify the temperature measurement technique, to screen possible materials for surface initiation of the laser absorption wave and to attempt to initiate an absorption wave using the 1.5 kW carbon dioxide laser. The OLD technique was proven for air and for argon, but spark breakdown could not be produced in helium. It was not possible to initiate a laser absorption wave in mixtures of water and helium or water and argon using the 1.5 kW laser, a result which was consistent with the model prediction.

  1. 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

  2. The evolution and exploitation of the fiber-optic hydrophone

    NASA Astrophysics Data System (ADS)

    Hill, David J.

    2007-07-01

    In the late 1970s one of the first applications identified for fibre-optic sensing was the fibre-optic hydrophone. It was recognised that the technology had the potential to provide a cost effective solution for large-scale arrays of highly sensitive hydrophones which could be interrogated over large distances. Consequently both the United Kingdom and United States navies funded the development of this sonar technology to the point that it is now deployed on submarines and as seabed arrays. The basic design of a fibre-optic hydrophone has changed little; comprising a coil of optical fibre wound on a compliant mandrel, interrogated using interferometric techniques. Although other approaches are being investigated, including the development of fibre-laser hydrophones, the interferometric approach remains the most efficient way to create highly multiplexed arrays of acoustic sensors. So much so, that the underlying technology is now being exploited in civil applications. Recently the exploration and production sector of the oil and gas industry has begun funding the development of fibre-optic seismic sensing using seabed mounted, very large-scale arrays of four component (three accelerometers and a hydrophone) packages based upon the original technology developed for sonar systems. This has given new impetus to the development of the sensors and the associated interrogation systems which has led to the technology being adopted for other commercial uses. These include the development of networked in-road fibre-optic Weigh-in-Motion sensors and of intruder detection systems which are able to acoustically monitor long lengths of border, on both land and at sea. After two decades, the fibre-optic hydrophone and associated technology has matured and evolved into a number of highly capable sensing solutions used by a range of industries.

  3. 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. © 2015 Society for Conservation Biology.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. Cytosolic proteins can exploit membrane localization to trigger functional assembly

    PubMed Central

    2018-01-01

    Cell division, endocytosis, and viral budding would not function without the localization and assembly of protein complexes on membranes. What is poorly appreciated, however, is that by localizing to membranes, proteins search in a reduced space that effectively drives up concentration. Here we derive an accurate and practical analytical theory to quantify the significance of this dimensionality reduction in regulating protein assembly on membranes. We define a simple metric, an effective equilibrium constant, that allows for quantitative comparison of protein-protein interactions with and without membrane present. To test the importance of membrane localization for driving protein assembly, we collected the protein-protein and protein-lipid affinities, protein and lipid concentrations, and volume-to-surface-area ratios for 46 interactions between 37 membrane-targeting proteins in human and yeast cells. We find that many of the protein-protein interactions between pairs of proteins involved in clathrin-mediated endocytosis in human and yeast cells can experience enormous increases in effective protein-protein affinity (10–1000 fold) due to membrane localization. Localization of binding partners thus triggers robust protein complexation, suggesting that it can play an important role in controlling the timing of endocytic protein coat formation. Our analysis shows that several other proteins involved in membrane remodeling at various organelles have similar potential to exploit localization. The theory highlights the master role of phosphoinositide lipid concentration, the volume-to-surface-area ratio, and the ratio of 3D to 2D equilibrium constants in triggering (or preventing) constitutive assembly on membranes. Our simple model provides a novel quantitative framework for interpreting or designing in vitro experiments of protein complexation influenced by membrane binding. PMID:29505559

  9. 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

  10. Exploiting combinatorial cultivation conditions to infer transcriptional regulation

    PubMed Central

    Knijnenburg, Theo A; de Winde, Johannes H; Daran, Jean-Marc; Daran-Lapujade, Pascale; Pronk, Jack T; Reinders, Marcel JT; Wessels, Lodewyk FA

    2007-01-01

    Background Regulatory networks often employ the model that attributes changes in gene expression levels, as observed across different cellular conditions, to changes in the activity of transcription factors (TFs). Although the actual conditions that trigger a change in TF activity should form an integral part of the generated regulatory network, they are usually lacking. This is due to the fact that the large heterogeneity in the employed conditions and the continuous changes in environmental parameters in the often used shake-flask cultures, prevent the unambiguous modeling of the cultivation conditions within the computational framework. Results We designed an experimental setup that allows us to explicitly model the cultivation conditions and use these to infer the activity of TFs. The yeast Saccharomyces cerevisiae was cultivated under four different nutrient limitations in both aerobic and anaerobic chemostat cultures. In the chemostats, environmental and growth parameters are accurately controlled. Consequently, the measured transcriptional response can be directly correlated with changes in the limited nutrient or oxygen concentration. We devised a tailor-made computational approach that exploits the systematic setup of the cultivation conditions in order to identify the individual and combined effects of nutrient limitations and oxygen availability on expression behavior and TF activity. Conclusion Incorporating the actual growth conditions when inferring regulatory relationships provides detailed insight in the functionality of the TFs that are triggered by changes in the employed cultivation conditions. For example, our results confirm the established role of TF Hap4 in both aerobic regulation and glucose derepression. Among the numerous inferred condition-specific regulatory associations between gene sets and TFs, also many novel putative regulatory mechanisms, such as the possible role of Tye7 in sulfur metabolism, were identified. PMID:17241460

  11. Exploiting combinatorial cultivation conditions to infer transcriptional regulation.

    PubMed

    Knijnenburg, Theo A; de Winde, Johannes H; Daran, Jean-Marc; Daran-Lapujade, Pascale; Pronk, Jack T; Reinders, Marcel J T; Wessels, Lodewyk F A

    2007-01-22

    Regulatory networks often employ the model that attributes changes in gene expression levels, as observed across different cellular conditions, to changes in the activity of transcription factors (TFs). Although the actual conditions that trigger a change in TF activity should form an integral part of the generated regulatory network, they are usually lacking. This is due to the fact that the large heterogeneity in the employed conditions and the continuous changes in environmental parameters in the often used shake-flask cultures, prevent the unambiguous modeling of the cultivation conditions within the computational framework. We designed an experimental setup that allows us to explicitly model the cultivation conditions and use these to infer the activity of TFs. The yeast Saccharomyces cerevisiae was cultivated under four different nutrient limitations in both aerobic and anaerobic chemostat cultures. In the chemostats, environmental and growth parameters are accurately controlled. Consequently, the measured transcriptional response can be directly correlated with changes in the limited nutrient or oxygen concentration. We devised a tailor-made computational approach that exploits the systematic setup of the cultivation conditions in order to identify the individual and combined effects of nutrient limitations and oxygen availability on expression behavior and TF activity. Incorporating the actual growth conditions when inferring regulatory relationships provides detailed insight in the functionality of the TFs that are triggered by changes in the employed cultivation conditions. For example, our results confirm the established role of TF Hap4 in both aerobic regulation and glucose derepression. Among the numerous inferred condition-specific regulatory associations between gene sets and TFs, also many novel putative regulatory mechanisms, such as the possible role of Tye7 in sulfur metabolism, were identified.

  12. 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)).

  13. Trawling bats exploit an echo-acoustic ground effect

    PubMed Central

    Zsebok, Sandor; Kroll, Ferdinand; Heinrich, Melina; Genzel, Daria; Siemers, Björn M.; Wiegrebe, Lutz

    2013-01-01

    A water surface acts not only as an optic mirror but also as an acoustic mirror. Echolocation calls emitted by bats at low heights above water are reflected away from the bat, and hence the background clutter is reduced. Moreover, targets on the surface create an enhanced echo. Here, we formally quantified the effect of the surface and target height on both target detection and -discrimination in a combined laboratory and field approach with Myotis daubentonii. In a two-alternative, forced-choice paradigm, the bats had to detect a mealworm and discriminate it from an inedible dummy (20 mm PVC disc). Psychophysical performance was measured as a function of height above either smooth surfaces (water or PVC) or above a clutter surface (artificial grass). At low heights above the clutter surface (10, 20, or 35 cm), the bats' detection performance was worse than above a smooth surface. At a height of 50 cm, the surface structure had no influence on target detection. Above the clutter surface, also target discrimination was significantly impaired with decreasing target height. A detailed analysis of the bats' echolocation calls during target approach shows that above the clutter surface, the bats produce calls with significantly higher peak frequency. Flight-path reconstruction revealed that the bats attacked an target from below over water but from above over a clutter surface. These results are consistent with the hypothesis that trawling bats exploit an echo-acoustic ground effect, in terms of a spatio-temporal integration of direct reflections with indirect reflections from the water surface, to optimize prey detection and -discrimination not only for prey on the water but also for some range above. PMID:23576990

  14. 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

  15. 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

  16. Trauma-Focused Cognitive Behavioral Therapy for Commercially Sexually Exploited Youth.

    PubMed

    Cohen, Judith A; Mannarino, Anthony P; Kinnish, Kelly

    2017-06-01

    Commercially sexually exploited children and adolescents ("commercially exploited youth")present numerous clinical challenges that have led some mental health providers to question whether current evidence-based treatments are adequate to address the needs of this population. This paper 1) addresses commonalities between the trauma experiences, responses and treatment challenges of commercially exploited youth and those of youth with complex trauma; 2) highlights the importance of careful assessment to guide case conceptualization and treatment planning for commercially exploited youth; and 3) describes strategies for implementing Trauma-Focused Cognitive Behavioral Therapy for complex trauma specific to these youth.

  17. Financial Exploitation Is Associated With Structural and Functional Brain Differences in Healthy Older Adults

    PubMed Central

    Spreng, R. Nathan; Cassidy, Benjamin N; Darboh, Bri S; DuPre, Elizabeth; Lockrow, Amber W; Setton, Roni; Turner, Gary R

    2017-01-01

    Abstract Background Age-related brain changes leading to altered socioemotional functioning may increase vulnerability to financial exploitation. If confirmed, this would suggest a novel mechanism leading to heightened financial exploitation risk in older adults. Development of predictive neural markers could facilitate increased vigilance and prevention. In this preliminary study, we sought to identify structural and functional brain differences associated with financial exploitation in older adults. Methods Financially exploited older adults (n = 13, 7 female) and a matched cohort of older adults who had been exposed to, but avoided, a potentially exploitative situation (n = 13, 7 female) were evaluated. Using magnetic resonance imaging, we examined cortical thickness and resting state functional connectivity. Behavioral data were collected using standardized cognitive assessments, self-report measures of mood and social functioning. Results The exploited group showed cortical thinning in anterior insula and posterior superior temporal cortices, regions associated with processing affective and social information, respectively. Functional connectivity encompassing these regions, within default and salience networks, was reduced, while between network connectivity was increased. Self-reported anger and hostility was higher for the exploited group. Conclusions We observed financial exploitation associated with brain differences in regions involved in socioemotional functioning. These exploratory and preliminary findings suggest that alterations in brain regions implicated in socioemotional functioning may be a marker of financial exploitation risk. Large-scale, prospective studies are necessary to validate this neural mechanism, and develop predictive markers for use in clinical practice. PMID:28369260

  18. Financial Exploitation Is Associated With Structural and Functional Brain Differences in Healthy Older Adults.

    PubMed

    Spreng, R Nathan; Cassidy, Benjamin N; Darboh, Bri S; DuPre, Elizabeth; Lockrow, Amber W; Setton, Roni; Turner, Gary R

    2017-10-01

    Age-related brain changes leading to altered socioemotional functioning may increase vulnerability to financial exploitation. If confirmed, this would suggest a novel mechanism leading to heightened financial exploitation risk in older adults. Development of predictive neural markers could facilitate increased vigilance and prevention. In this preliminary study, we sought to identify structural and functional brain differences associated with financial exploitation in older adults. Financially exploited older adults (n = 13, 7 female) and a matched cohort of older adults who had been exposed to, but avoided, a potentially exploitative situation (n = 13, 7 female) were evaluated. Using magnetic resonance imaging, we examined cortical thickness and resting state functional connectivity. Behavioral data were collected using standardized cognitive assessments, self-report measures of mood and social functioning. The exploited group showed cortical thinning in anterior insula and posterior superior temporal cortices, regions associated with processing affective and social information, respectively. Functional connectivity encompassing these regions, within default and salience networks, was reduced, while between network connectivity was increased. Self-reported anger and hostility was higher for the exploited group. We observed financial exploitation associated with brain differences in regions involved in socioemotional functioning. These exploratory and preliminary findings suggest that alterations in brain regions implicated in socioemotional functioning may be a marker of financial exploitation risk. Large-scale, prospective studies are necessary to validate this neural mechanism, and develop predictive markers for use in clinical practice. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America.

  19. UV laser long-path absorption spectroscopy

    NASA Technical Reports Server (NTRS)

    Dorn, Hans-Peter; Brauers, Theo; Neuroth, Rudolf

    1994-01-01

    Long path Differential Optical Absorption Spectroscopy (DOAS) using a picosecond UV laser as a light source was developed in our institute. Tropospheric OH radicals are measured by their rotational absorption lines around 308 nm. The spectra are obtained using a high resolution spectrograph. The detection system has been improved over the formerly used optomechanical scanning device by application of a photodiode array which increased the observed spectral range by a factor of 6 and which utilizes the light much more effectively leading to a considerable reduction of the measurement time. This technique provides direct measurements of OH because the signal is given by the product of the absorption coefficient and the OH concentration along the light path according to Lambert-Beers law. No calibration is needed. Since the integrated absorption coefficient is well known the accuracy of the measurement essentially depends on the extent to which the OH absorption pattern can be detected in the spectra. No interference by self generated OH radicals in the detection lightpath has been observed. The large bandwidth (greater than 0.15 nm) and the high spectral resolution (1.5 pm) allows absolute determination of interferences by other trace gas absorptions. The measurement error is directly accessible from the absorption-signal to baseline-noise ratio in the spectra. The applicability of the method strongly depends on visibility. Elevated concentrations of aerosols lead to considerable attenuation of the laser light which reduces the S/N-ratio. In the moderately polluted air of Julich, where we performed a number of OH measurement spectra. In addition absorption features of unidentified species were frequently detected. A quantitative deconvolution even of the known species is not easy to achieve and can leave residual structures in the spectra. Thus interferences usually increase the noise and deteriorate the OH detection sensitivity. Using diode arrays for sensitive

  20. Phytosterol glycosides reduce cholesterol absorption in humans

    PubMed Central

    Lin, Xiaobo; Ma, Lina; Racette, Susan B.; Anderson Spearie, Catherine L.; Ostlund, Richard E.

    2009-01-01

    Dietary phytosterols inhibit intestinal cholesterol absorption and regulate whole body cholesterol excretion and balance. However, they are biochemically heterogeneous and a portion is glycosylated in some foods with unknown effects on biological activity. We tested the hypothesis that phytosterol glycosides reduce cholesterol absorption in humans. Phytosterol glycosides were extracted and purified from soy lecithin in a novel two-step process. Cholesterol absorption was measured in a series of three single-meal tests given at intervals of 2 wk to each of 11 healthy subjects. In a randomized crossover design, participants received ∼300 mg of added phytosterols in the form of phytosterol glycosides or phytosterol esters, or placebo in a test breakfast also containing 30 mg cholesterol-d7. Cholesterol absorption was estimated by mass spectrometry of plasma cholesterol-d7 enrichment 4–5 days after each test. Compared with the placebo test, phytosterol glycosides reduced cholesterol absorption by 37.6 ± 4.8% (P < 0.0001) and phytosterol esters 30.6 ± 3.9% (P = 0.0001). These results suggest that natural phytosterol glycosides purified from lecithin are bioactive in humans and should be included in methods of phytosterol analysis and tables of food phytosterol content. PMID:19246636

  1. Optical absorption in recycled waste plastic polyethylene

    NASA Astrophysics Data System (ADS)

    Aji, M. P.; Rahmawati, I.; Priyanto, A.; Karunawan, J.; Wati, A. L.; Aryani, N. P.; Susanto; Wibowo, E.; Sulhadi

    2018-03-01

    We investigated the optical properties of UV spectrum absorption in recycled waste plastic from polyethylene polymer type. Waste plastic polyethylene showed an optical spectrum absorption after it’s recycling process. Spectrum absorption is determined using spectrophotometer UV-Nir Ocean Optics type USB 4000. Recycling method has been processed using heating treatment around the melting point temperature of the polyethylene polymer that are 200°C, 220°C, 240°C, 260°C, and 280°C. In addition, the recycling process was carried out with time variations as well, which are 1h, 1.5h, 2h, and 2.5h. The result of this experiment shows that recycled waste plastic polyethylene has a spectrum absorption in the ∼ 340-550 nm wavelength range. The absorbance spectrum obtained from UV light which is absorbed in the orbital n → π* and the orbital π → π*. This process indicates the existence of electron transition phenomena. This mechanism is affected by the temperature and the heating time where the intensity of absorption increases and widens with the increase of temperature and heating time. Furthermore this study resulted that the higher temperature affected the enhancement of the band gap energy of waste plastic polyethylene. These results show that recycled waste plastic polyethylene has a huge potential to be absorber materials for solar cell.

  2. Creating semiconductor metafilms with designer absorption spectra

    SciTech Connect

    Kim, Soo Jin; Fan, Pengyu; Kang, Ju-Hyung

    The optical properties of semiconductors are typically considered intrinsic and fixed. Here we leverage the rapid developments in the field of optical metamaterials to create ultrathin semiconductor metafilms with designer absorption spectra. We show how such metafilms can be constructed by placing one or more types of high-index semiconductor antennas into a dense array with subwavelength spacings. It is argued that the large absorption cross-section of semiconductor antennas and their weak near-field coupling open a unique opportunity to create strongly absorbing metafilms whose spectral absorption properties directly reflect those of the individual antennas. Using experiments and simulations, we demonstrate thatmore » near-unity absorption at one or more target wavelengths of interest can be achieved in a sub-50-nm-thick metafilm using judiciously sized and spaced Ge nanobeams. The ability to create semiconductor metafilms with custom absorption spectra opens up new design strategies for planar optoelectronic devices and solar cells.« less

  3. Absorption coefficients of silicon: A theoretical treatment

    NASA Astrophysics Data System (ADS)

    Tsai, Chin-Yi

    2018-05-01

    A theoretical model with explicit formulas for calculating the optical absorption and gain coefficients of silicon is presented. It incorporates direct and indirect interband transitions and considers the effects of occupied/unoccupied carrier states. The indirect interband transition is calculated from the second-order time-independent perturbation theory of quantum mechanics by incorporating all eight possible routes of absorption or emission of photons and phonons. Absorption coefficients of silicon are calculated from these formulas. The agreements and discrepancies among the calculated results, the Rajkanan-Singh-Shewchun (RSS) formula, and Green's data are investigated and discussed. For example, the RSS formula tends to overestimate the contributions of indirect transitions for cases with high photon energy. The results show that the state occupied/unoccupied effect is almost negligible for silicon absorption coefficients up to the onset of the optical gain condition where the energy separation of Quasi-Femi levels between electrons and holes is larger than the band-gap energy. The usefulness of using the physics-based formulas, rather than semi-empirical fitting ones, for absorption coefficients in theoretical studies of photovoltaic devices is also discussed.

  4. Dynamics of water absorption through superabsorbent polymer

    NASA Astrophysics Data System (ADS)

    Chang, Sooyoung; Kim, Wonjung

    2017-11-01

    Superabsorbent polymers (SAPs) consist of hydrophilic cross-linked polymer networks that can absorb and retain a great amount of water relative to their own mass, so that they are widely used for disposable diapers and holding soil moisture in agriculture. SAPs are typically available in the form of submillimeter-sized particles, and the water absorption is driven by capillary flows between particles as well as diffusion that entail swelling. Although the control of water absorption of SAPs is important in engineering applications, but the dynamics of water absorption in SAP particles has not been fully understood. We examine the dynamics of the water absorption of sodium polyacrylate, one of the most common SAP. We experimentally measured the water absorption of sodium polyacrylate particles in one-dimensional confined channel. The water flows through the particles were analyzed by capillarity dominant at the early stage and by diffusion involving volume expansion critical at a later stage. The results provide a quantitative basis of the hydrodynamic analysis of the water flow through SAP particles from a macroscopic point of view, facilitating the prediction of water uptake of SAPs in hygienic and agricultural applications. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No.2015R1A2A2A04006181).

  5. Aerosol Absorption Measurements from LANDSAT and CIMEL

    NASA Technical Reports Server (NTRS)

    Kaufman, Y. J.; Tanre, D.; Karnieli, A.; Remer, L.; Holben, B.

    1999-01-01

    Spectral remote observations of dust properties from space and from the ground create a powerful tool for determination of dust absorption of solar radiation with an unprecedented accuracy. Absorption is a key component in understanding dust impact on climate. We use Landsat space-borne measurements at 0.47 to 2.2 micrometer over Senegal with ground-based sunphotometers to find that Saharan dust absorption of solar radiation is two to four times smaller than in models. Though dust absorbs in the blue, almost no absorption was found for wavelengths greater than 0.6 micrometer. The new finding increases by 50% recent estimated solar radiative forcing by dust and decreases the estimated dust heating of the lower troposphere. Dust transported from Asia shows slightly higher absorption probably due to the presence of black carbon from populated regions. Large-scale application of this method to satellite data from the Earth Observing System can reduce significantly the uncertainty in the dust radiative effects.

  6. Controlling enhanced absorption in graphene metamaterial

    NASA Astrophysics Data System (ADS)

    Zhou, Qihui; Liu, Peiguo; Bian, Li-an; Liu, Hanqing; Liu, Chenxi; Chen, Genghui

    2018-04-01

    In this paper, a controllable terahertz (THz) metamaterial absorber (MA) is designed with the circuit analog method. Taking advantage of the patterned graphene on SiO2/doped Si/polyimide substrates with a gold reflector, the controllable MA achieves perfect absorption at 0.75 THz. The chemical potential of graphene is regulated by controlling the voltage between graphene and doped Si layers. As the chemical potential varies from 0 eV to 0.5 eV, the MA is changed from reflection (<0.37) to absorption (>0.99). The distributions of surface current and electric field are illustrated to analyze the resonant characteristic of patterned graphene. According to the resonant characteristic, we introduce patterned graphene elements with different dimension in a unit cell, which effectively extends the effective absorption bandwidth (absorption > 0 . 9) from 0.67-0.93 THz to 0.52-0.95 THz. Moreover, replacing part of the graphene structure with gold, the switchable MA is turned into a frequency tunable MA. The absorption peak moves from 0.62 THz to 0.92 THz as the chemical potential increases from 0.1 eV to 0.5 eV. These designs overcome limitation of traditional absorbers and exhibit great potentials in many practical applications.

  7. Identifying the perfect absorption of metamaterial absorbers

    NASA Astrophysics Data System (ADS)

    Duan, G.; Schalch, J.; Zhao, X.; Zhang, J.; Averitt, R. D.; Zhang, X.

    2018-01-01

    We present a detailed analysis of the conditions that result in unity absorption in metamaterial absorbers to guide the design and optimization of this important class of functional electromagnetic composites. Multilayer absorbers consisting of a metamaterial layer, dielectric spacer, and ground plane are specifically considered. Using interference theory, the dielectric spacer thickness and resonant frequency for unity absorption can be numerically determined from the functional dependence of the relative phase shift of the total reflection. Further, using transmission line theory in combination with interference theory we obtain analytical expressions for the unity absorption resonance frequency and corresponding spacer layer thickness in terms of the bare resonant frequency of the metamaterial layer and metallic and dielectric losses within the absorber structure. These simple expressions reveal a redshift of the unity absorption frequency with increasing loss that, in turn, necessitates an increase in the thickness of the dielectric spacer. The results of our analysis are experimentally confirmed by performing reflection-based terahertz time-domain spectroscopy on fabricated absorber structures covering a range of dielectric spacer thicknesses with careful control of the loss accomplished through water absorption in a semiporous polyimide dielectric spacer. Our findings can be widely applied to guide the design and optimization of the metamaterial absorbers and sensors.

  8. 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

  9. Exploiting the systematic review protocol for classification of medical abstracts.

    PubMed

    Frunza, Oana; Inkpen, Diana; Matwin, Stan; Klement, William; O'Blenis, Peter

    2011-01-01

    To determine whether the automatic classification of documents can be useful in systematic reviews on medical topics, and specifically if the performance of the automatic classification can be enhanced by using the particular protocol of questions employed by the human reviewers to create multiple classifiers. The test collection is the data used in large-scale systematic review on the topic of the dissemination strategy of health care services for elderly people. From a group of 47,274 abstracts marked by human reviewers to be included in or excluded from further screening, we randomly selected 20,000 as a training set, with the remaining 27,274 becoming a separate test set. As a machine learning algorithm we used complement naïve Bayes. We tested both a global classification method, where a single classifier is trained on instances of abstracts and their classification (i.e., included or excluded), and a novel per-question classification method that trains multiple classifiers for each abstract, exploiting the specific protocol (questions) of the systematic review. For the per-question method we tested four ways of combining the results of the classifiers trained for the individual questions. As evaluation measures, we calculated precision and recall for several settings of the two methods. It is most important not to exclude any relevant documents (i.e., to attain high recall for the class of interest) but also desirable to exclude most of the non-relevant documents (i.e., to attain high precision on the class of interest) in order to reduce human workload. For the global method, the highest recall was 67.8% and the highest precision was 37.9%. For the per-question method, the highest recall was 99.2%, and the highest precision was 63%. The human-machine workflow proposed in this paper achieved a recall value of 99.6%, and a precision value of 17.8%. The per-question method that combines classifiers following the specific protocol of the review leads to better

  10. Exploiting Fission Chain Reaction Dynamics to Image Fissile Materials

    NASA Astrophysics Data System (ADS)

    Chapman, Peter Henry

    Radiation imaging is one potential method to verify nuclear weapons dismantlement. The neutron coded aperture imager (NCAI), jointly developed by Oak Ridge National Laboratory (ORNL) and Sandia National Laboratories (SNL), is capable of imaging sources of fast (e.g., fission spectrum) neutrons using an array of organic scintillators. This work presents a method developed to discriminate between non-multiplying (i.e., non-fissile) neutron sources and multiplying (i.e., fissile) neutron sources using the NCAI. This method exploits the dynamics of fission chain-reactions; it applies time-correlated pulse-height (TCPH) analysis to identify neutrons in fission chain reactions. TCPH analyzes the neutron energy deposited in the organic scintillator vs. the apparent neutron time-of-flight. Energy deposition is estimated from light output, and time-of-flight is estimated from the time between the neutron interaction and the immediately preceding gamma interaction. Neutrons that deposit more energy than can be accounted for by their apparent time-of-flight are identified as fission chain-reaction neutrons, and the image is reconstructed using only these neutron detection events. This analysis was applied to measurements of weapons-grade plutonium (WGPu) metal and 252Cf performed at the Nevada National Security Site (NNSS) Device Assembly Facility (DAF) in July 2015. The results demonstrate it is possible to eliminate the non-fissile 252Cf source from the image while preserving the fissileWGPu source. TCPH analysis was also applied to additional scenes in which theWGPu and 252Cf sources were measured individually. The results of these separate measurements further demonstrate the ability to remove the non-fissile 252Cf source and retain the fissileWGPu source. Simulations performed using MCNPX-PoliMi indicate that in a one hour measurement, solid spheres ofWGPu are retained at a 1sigma level for neutron multiplications M -˜ 3.0 and above, while hollowWGPu spheres are

  11. Understanding turbulence in compressing plasmas and its exploitation or prevention.

    SciTech Connect

    Davidovits, Seth

    Unprecedented densities and temperatures are now achieved in compressions of plasma, by lasers and by pulsed power, in major experimental facilities. These compressions, carried out at the largest scale at the National Ignition Facility and at the Z Pulsed Power Facility, have important applications, including fusion, X-ray production, and materials research. Several experimental and simulation results suggest that the plasma in some of these compressions is turbulent. In fact, measurements suggest that in certain laboratory plasma compressions the turbulent energy is a dominant energy component. Similarly, turbulence is dominant in some compressing astrophysical plasmas, such as in molecular clouds. Turbulencemore » need not be dominant to be important; even small quantities could greatly influence experiments that are sensitive to mixing of non-fuel into fuel, such as compressions seeking fusion ignition. Despite its important role in major settings, bulk plasma turbulence under compression is insufficiently understood to answer or even to pose some of the most fundamental questions about it. This thesis both identifies and answers key questions in compressing turbulent motion, while providing a description of the behavior of three-dimensional, isotropic, compressions of homogeneous turbulence with a plasma viscosity. This description includes a simple, but successful, new model for the turbulent energy of plasma undergoing compression. The unique features of compressing turbulence with a plasma viscosity are shown, including the sensitivity of the turbulence to plasma ionization, and a sudden viscous dissipation'' effect which rapidly converts plasma turbulent energy into thermal energy. This thesis then examines turbulence in both laboratory compression experiments and molecular clouds. It importantly shows: the possibility of exploiting turbulence to make fusion or X-ray production more efficient; conditions under which hot-spot turbulence can be prevented

  12. 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

  13. 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.

  14. 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.

  15. Exploiting passive polarimetric imagery for remote sensing applications

    NASA Astrophysics Data System (ADS)

    Vimal Thilak Krishna, Thilakam

    Polarization is a property of light or electromagnetic radiation that conveys information about the orientation of the transverse electric and magnetic fields. The polarization of reflected light complements other electromagnetic radiation attributes such as intensity, frequency, or spectral characteristics. A passive polarization based imaging system records the polarization state of light reflected by objects that are illuminated with an unpolarized and generally uncontrolled source. The polarization due to surface reflections from such objects contains information about the targets that can be exploited in remote sensing applications such as target detection, target classification, object recognition and shape extraction/recognition. In recent years, there has been renewed interest in the use of passive polarization information in remote sensing applications. The goal of our research is to design image processing algorithms for remote sensing applications by utilizing physics-based models that describe the polarization imparted by optical scattering from an object. In this dissertation, we present a method to estimate the complex index of refraction and reflection angle from multiple polarization measurements. This method employs a polarimetric bidirectional reflectance distribution function (pBRDF) that accounts for polarization due to specular scattering. The parameters of interest are derived by utilizing a nonlinear least squares estimation algorithm, and computer simulation results show that the estimation accuracy generally improves with an increasing number of source position measurements. Furthermore, laboratory results indicate that the proposed method is effective for recovering the reflection angle and that the estimated index of refraction provides a feature vector that is robust to the reflection angle. We also study the use of extracted index of refraction as a feature vector in designing two important image processing applications, namely image

  16. Exploitation dynamics of small fish stocks like Arctic cisco

    USGS Publications Warehouse

    Nielsen, Jennifer L.

    2004-01-01

    Potential impacts to the Arctic cisco population fall into both demographic and behavioral categories. Possible demographic impacts include stock recruitment effects, limited escapement into marine habitats, and variable age-class reproductive success. Potential behavioral impacts involve migratory patterns, variable life histories, and strategies for seasonal feeding. Arctic cisco stocks are highly susceptible to over-exploitation due to our limited basic knowledge of the highly variable Arctic environment and the role they play in this dynamic ecosystem.Our knowledge of potential demographic changes is very limited, and it is necessary to determine the abundance and recruitment of the hypothesized Mackenzie River source population, the extent of the coastal migratory corridor, growth patterns, and coastal upwelling and mixing effects on population dynamics for this species. Information needed to answer some of the demographic questions includes basic evolutionary history and molecular genetics of Arctic cisco (for instance, are there contributions to the Arctic cisco stock from the Yukon?), what is the effective population size (i.e., breeding population size), and potential links to changes in climate. The basic behavioral questions include migratory and variable life history questions. For instance, the extent of movement back and forth between freshwater and the sea, age-specific differences in food web dynamics, and nearshore brackish and high salinity habitats are topics that should be studied. Life history data should be gathered to understand the variation in age at reproduction, salinity tolerance, scale and duration of the freshwater stage, survival, and adult migration. Both molecular and ecological tools should be integrated to manage the Arctic cisco stock(s), such as understanding global climate changes on patterns of harvest and recruitment, and the genetics of population structure and colonization. Perhaps other populations are contributing to the

  17. Understanding Turbulence in Compressing Plasmas and Its Exploitation or Prevention

    NASA Astrophysics Data System (ADS)

    Davidovits, Seth

    Unprecedented densities and temperatures are now achieved in compressions of plasma, by lasers and by pulsed power, in major experimental facilities. These compressions, carried out at the largest scale at the National Ignition Facility and at the Z Pulsed Power Facility, have important applications, including fusion, X-ray production, and materials research. Several experimental and simulation results suggest that the plasma in some of these compressions is turbulent. In fact, measurements suggest that in certain laboratory plasma compressions the turbulent energy is a dominant energy component. Similarly, turbulence is dominant in some compressing astrophysical plasmas, such as in molecular clouds. Turbulence need not be dominant to be important; even small quantities could greatly influence experiments that are sensitive to mixing of non-fuel into fuel, such as compressions seeking fusion ignition. Despite its important role in major settings, bulk plasma turbulence under compression is insufficiently understood to answer or even to pose some of the most fundamental questions about it. This thesis both identifies and answers key questions in compressing turbulent motion, while providing a description of the behavior of three-dimensional, isotropic, compressions of homogeneous turbulence with a plasma viscosity. This description includes a simple, but successful, new model for the turbulent energy of plasma undergoing compression. The unique features of compressing turbulence with a plasma viscosity are shown, including the sensitivity of the turbulence to plasma ionization, and a "sudden viscous dissipation'' effect which rapidly converts plasma turbulent energy into thermal energy. This thesis then examines turbulence in both laboratory compression experiments and molecular clouds. It importantly shows: the possibility of exploiting turbulence to make fusion or X-ray production more efficient; conditions under which hot-spot turbulence can be prevented; and a

  18. On the exploitation of seismic resonances for cavity detection

    NASA Astrophysics Data System (ADS)

    Schneider, Felix M.; Esterhazy, Sofi; Perugia, Ilaria; Bokelmann, Götz

    2017-04-01

    . In synthetic seismograms calculated in the surrounding elastic domain, the acoustic resonances of gas-filled cavities show up as persisting oscillations. However, due to the weak acoustic-elastic coupling in this case the amplitudes of the oscillations are very low. Due to a lower impedance contrast, a fluid-filled cavity has a stronger acoustic-elastic coupling, which results in wide spectral peaks of lower amplitudes. In the synthetic seismograms derived in the surrounding medium of fluid-filled cavities, acoustic resonances show up as strong but fast decaying reverberations. Based on the analytical modeling methods for exploitation of these resonance features are developed and discussed.

  19. Iron absorption from Southeast Asian diets. II. Role of various factors that might explain low absorption.

    PubMed

    Hallberg, L; Björn-Rasmussen, E; Rossander, L; Suwanik, R

    1977-04-01

    Previously reported levels of iron absorption from common Southeast Asian meals composed of rice, vegetables, and spices were too low to be consistent with the known prevalence of iron deficiency. In the present paper the cause of the low absorption was systematically sought. Variables investigated comprised methodological errors, factors in the diet such as certain foodstuffs, or contaminants inhibiting the absorption and characteristics of the subjects accompanied by malabsorption of dietary iron. The latter was excluded by comparing the absorption from both wheat rolls and a composit rice meal in Thai and Swedish women using the absorption of a small dose of ferrous ascorbate as a common basis of comparison. Two main factors were identified as causing the low absorption in the previous studies: the homogenization of the labeled meals before serving and the use of rice flour instead of rice. Iron absorption from nonhomogenized meals of identical composition as studied previously was many times higher (on an average 0.16 mg) and was consistent with the actual prevalence of iron deficiency in lower socioeconomic groups of Thais mainly consuming the simple meals studied. Recent modifications of the method to measure nonheme iron absorption from composite meals have thus not only made the determination simpler but also more accurate.

  20. Plasmon absorption modulator systems and methods

    DOEpatents

    Kekatpure, Rohan Deodatta; Davids, Paul

    2014-07-15

    Plasmon absorption modulator systems and methods are disclosed. A plasmon absorption modulator system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and a metal layer formed on a top surface of the stack of quantum well layers. A method for modulating plasmonic current includes enabling propagation of the plasmonic current along a metal layer, and applying a voltage across the stack of quantum well layers to cause absorption of a portion of energy of the plasmonic current by the stack of quantum well layers. A metamaterial switching system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and at least one metamaterial structure formed on a top surface of the stack of quantum well layers.

  1. Nanofibrous membrane-based absorption refrigeration system

    SciTech Connect

    Isfahani, RN; Sampath, K; Moghaddam, S

    2013-12-01

    This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature,more » and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.« less

  2. Outskirts of Distant Galaxies in Absorption

    NASA Astrophysics Data System (ADS)

    Chen, Hsiao-Wen

    QSO absorption spectroscopy provides a sensitive probe of both the neutral medium and diffuse ionized gas in the distant Universe. It extends 21 cm maps of gaseous structures around low-redshift galaxies both to lower gas column densities and to higher redshifts. Combining galaxy surveys with absorption-line observations of gas around galaxies enables comprehensive studies of baryon cycles in galaxy outskirts over cosmic time. This chapter presents a review of the empirical understanding of the cosmic neutral gas reservoir from studies of damped Lyα absorbers (DLAs). It describes the constraints on the star formation relation and chemical enrichment history in the outskirts of distant galaxies from DLA studies. A brief discussion of available constraints on the ionized circumgalactic gas from studies of lower column density Lyα absorbers and associated ionic absorption transitions is presented at the end.

  3. Laser absorption phenomena in flowing gas devices

    NASA Technical Reports Server (NTRS)

    Chapman, P. K.; Otis, J. H.

    1976-01-01

    A theoretical and experimental investigation is presented of inverse Bremsstrahlung absorption of CW CO2 laser radiation in flowing gases seeded with alkali metals. In order to motivate this development, some simple models are described of several space missions which could use laser powered rocket vehicles. Design considerations are given for a test call to be used with a welding laser, using a diamond window for admission of laser radiation at power levels in excess of 10 kW. A detailed analysis of absorption conditions in the test cell is included. The experimental apparatus and test setup are described and the results of experiments presented. Injection of alkali seedant and steady state absorption of the laser radiation were successfully demonstrated, but problems with the durability of the diamond windows at higher powers prevented operation of the test cell as an effective laser powered thruster.

  4. Tunable electromagnetically induced absorption based on graphene

    NASA Astrophysics Data System (ADS)

    Cao, Maoyong; Wang, Tongling; Zhang, Huiyun; Zhang, Yuping

    2018-04-01

    In this paper, an electronically induced absorption (EIA) structure based on graphene at the infrared frequency is proposed. A pair of nanorods is coupled to a ring resonator, resulting in electronically induced transparency (EIT), and then, Babinet's principle is applied to transform the EIT structure into an EIA structure. Based on the bright and dark modes of the coupling schemes, the adjustment of the coupling strength between the dark and bright modes can be achieved by changing the asymmetry degree. In addition, the transparency window and the absorption peak can be tuned by changing the Fermi energy of graphene. This graphene-based EIA structure can develop the path in narrow-band filtering and, absorptive switching in the future.

  5. A Review: Characteristics of Noise Absorption Material

    NASA Astrophysics Data System (ADS)

    Amares, S.; Sujatmika, E.; Hong, T. W.; Durairaj, R.; Hamid, H. S. H. B.

    2017-10-01

    Noise is always treated as a nuisance to human and even noise pollution appears in the environmental causing discomfort. This also concerns the engineering design that tends to cultivate this noise propagation. Solution such as using material to absorb the sound have been widely used. The fundamental of the sound absorbing propagation, sound absorbing characteristics and its factors are minimally debated. Furthermore, the method in order to pertain sound absorbing related to the sound absorption coefficient is also limited, as many studies only contributes in result basis and very little in literature aspect. This paper revolves in providing better insight on the importance of sound absorption and the materials factors in obtaining the sound absorption coefficient.

  6. Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

    NASA Astrophysics Data System (ADS)

    Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (<0.1micron) were also collected at site T0 and T1 (Universidad Technologica de Tecamac, State of Mexico) from 5 am to 5 pm (day) and from 5 pm to 5 am (night) during the month of March 2006. Samples were collected on quartz fiber filters with high volume impactor samplers. Continuous absorption spectra of these aerosol samples have been obtained in the laboratory from 280 to 900nm with the use of an integrating sphere coupled to a UV spectrometer (Beckman DU with a Labsphere accessory). The integrating sphere allows the detector to collect and spatially integrate the total radiant flux reflected from the sample and therefore allows for the measurement of absorption on highly reflective or diffusely scattering samples. These continuous spectra have also been used to obtain the

  7. Intestinal fluid absorption in spontaneously hypertensive rats.

    PubMed Central

    Dorey, P G; King, J; Munday, K A; Parsons, B J; Poat, J A

    1983-01-01

    A comparison has been made of intestinal fluid absorption between male Okamoto spontaneously hypertensive rats (s.h.r.) and normotensive male Wistar controls. S.h.r. show enhanced fluid absorption both in hypertensive adults and in young s.h.r. before hypertension has developed. Several potential causes for increased fluid transport in s.h.r. were tested using pharmacological antagonists. It is unlikely that enhanced fluid absorption is due to high sympathetic nervous activity, the renin-angiotensin system or is secondary to hypertension. Intestine from s.h.r. have a high short-circuit current indicating a change in ion pump activity. These results are discussed in relation to the possible causes of increased fluid (ion) transport by the intestine of s.h.r. PMID:6361232

  8. Subwavelength total acoustic absorption with degenerate resonators

    NASA Astrophysics Data System (ADS)

    Yang, Min; Meng, Chong; Fu, Caixing; Li, Yong; Yang, Zhiyu; Sheng, Ping

    2015-09-01

    We report the experimental realization of perfect sound absorption by sub-wavelength monopole and dipole resonators that exhibit degenerate resonant frequencies. This is achieved through the destructive interference of two resonators' transmission responses, while the matching of their averaged impedances to that of air implies no backscattering, thereby leading to total absorption. Two examples, both using decorated membrane resonators (DMRs) as the basic units, are presented. The first is a flat panel comprising a DMR and a pair of coupled DMRs, while the second one is a ventilated short tube containing a DMR in conjunction with a sidewall DMR backed by a cavity. In both examples, near perfect absorption, up to 99.7%, has been observed with the airborne wavelength up to 1.2 m, which is at least an order of magnitude larger than the composite absorber. Excellent agreement between theory and experiment is obtained.

  9. Resonant indirect optical absorption in germanium

    NASA Astrophysics Data System (ADS)

    Menéndez, José; Noël, Mario; Zwinkels, Joanne C.; Lockwood, David J.

    2017-09-01

    The optical absorption coefficient of pure Ge has been determined from high-accuracy, high-precision optical measurements at photon energies covering the spectral range between the indirect and direct gaps. The results are compared with a theoretical model that fully accounts for the resonant nature of the energy denominators that appear in perturbation-theory expansions of the absorption coefficient. The model generalizes the classic Elliott approach to indirect excitons, and leads to a predicted optical absorption that is in excellent agreement with the experimental values using just a single adjustable parameter: the average deformation potential DΓ L coupling electrons at the bottom of the direct and indirect valleys in the conduction band. Remarkably, the fitted value, DΓ L=4.3 ×108eV /cm , is in nearly perfect agreement with independent measurements and ab initio predictions of this parameter, confirming the validity of the proposed theory, which has general applicability.

  10. Absorption of acoustic waves by sunspots. II - Resonance absorption in axisymmetric fibril models

    NASA Technical Reports Server (NTRS)

    Rosenthal, C. S.

    1992-01-01

    Analytical calculations of acoustic waves scattered by sunspots which concentrate on the absorption at the magnetohydrodynamic Alfven resonance are extended to the case of a flux-tube embedded in a uniform atmosphere. The model is based on a flux-tubes of varying radius that are highly structured, translationally invariant, and axisymmetric. The absorbed fractional energy is determined for different flux-densities and subphotospheric locations with attention given to the effects of twist. When the flux is highly concentrated into annuli efficient absorption is possible even when the mean magnetic flux density is low. The model demonstrates low absorption at low azimuthal orders even in the presence of twist which generally increases the range of wave numbers over which efficient absorption can occur. Resonance absorption is concluded to be an efficient mechanism in monolithic sunspots, fibril sunspots, and plage fields.

  11. Intestinal absorption of copper: influence of carbohydrates.

    PubMed

    Wapnir, R A; Balkman, C

    1992-02-01

    Macronutrients can modulate the intestinal absorption of trace elements by binding the metal or altering mucosal function. We investigated whether certain simple and complex carbohydrates modify copper (Cu) absorption, using an in vivo perfusion technique in the rat. Corn syrup solids, which contain a mixture of glucose polymers of diverse length, added at either 20 or 50 mosm/kg enhanced Cu absorption from a 31.5 microM (2 mg/liter) Cu solution (128 +/- 11 and 130 +/- 11 pmol/min x cm, respectively, vs 101 +/- 4 pmol/min x cm, P less than 0.05, in the absence of carbohydrate). This was concomitant with a stimulation of net water absorption (1.05 +/- 0.08 and 0.84 +/- 0.08 microliter/min x cm, respectively, vs 0.63 +/- 0.02 microliter/min x cm with no carbohydrate, P less than 0.05). Glucose, fructose, lactose, or sucrose had no influence on Cu absorption, although they altered water exchanges, an effect attributable to a reduction of the outflow component of fluid recirculation. Low concentrations of lactose resulted in a greater accumulation of Cu in the intestinal mucosa (8.75 +/- 0.71 micrograms/g vs 5.77 +/- 0.68 micrograms/g for controls, P less than 0.05). Hence, solutes that moderately stimulate mucosa-to-serosa fluid influx in a progressive manner, such as glucose polymers, may contribute to functionally increase Cu absorption. Conversely, conditions which tend to reduce water inflow or increase water outflow across the small intestinal mucosa, as may occur with high lactose diets or in cases of chronic diarrhea, may have negative effects.

  12. Calcium absorption is not increased by caseinophosphopeptides.

    PubMed

    Teucher, Birgit; Majsak-Newman, Gosia; Dainty, Jack R; McDonagh, David; FitzGerald, Richard J; Fairweather-Tait, Susan J

    2006-07-01

    One of the suggested health benefits of caseinophosphopeptides (CPPs) is their ability to enhance calcium absorption. This possibility is based on the assumption that they resist proteolysis in the upper gastrointestinal tract and maintain calcium in a soluble form at alkaline pH in the distal ileum. The effects of CPP-enriched preparations (containing candidate functional food ingredients) on calcium absorption from a calcium lactate drink were tested. A randomized crossover trial was undertaken in 15 adults in whom we measured the absorption of calcium from a calcium lactate drink (drink A: 400 mg Ca as lactate) and 2 preparations enriched with forms of CPP (1.7 g each; drinks B and C). Both drinks B and C contained 400 mg Ca as calcium lactate plus approximately 100 mg CPP-derived calcium). Each volunteer received the 3 drinks in random order. Absorption was measured by the dual-label calcium stable-isotope technique. The quantity of calcium absorbed was significantly lower from drink A (103 mg) than from drink B (117 mg; P = 0.012) or drink C (121 mg; P = 0.002), which indicated a positive effect of the CPPs. However, because the CPP preparations contributed additional calcium besides that found in the calcium lactate (drink A), fractional absorption of calcium from drink B (23%) was slightly but significantly (P = 0.015) lower than that from drink A (26%). The differences in calcium absorption are unlikely to have any biological significance. CPPs are unsuitable as candidate ingredients for functional foods that are designed to deliver improved calcium nutrition.

  13. Dietary Phospholipids and Intestinal Cholesterol Absorption

    PubMed Central

    Cohn, Jeffrey S.; Kamili, Alvin; Wat, Elaine; Chung, Rosanna W. S.; Tandy, Sally

    2010-01-01

    Experiments carried out with cultured cells and in experimental animals have consistently shown that phospholipids (PLs) can inhibit intestinal cholesterol absorption. Limited evidence from clinical studies suggests that dietary PL supplementation has a similar effect in man. A number of biological mechanisms have been proposed in order to explain how PL in the gut lumen is able to affect cholesterol uptake by the gut mucosa. Further research is however required to establish whether the ability of PLs to inhibit cholesterol absorption is of therapeutic benefit. PMID:22254012

  14. Subbarrier absorption in a stationary superlattice

    NASA Technical Reports Server (NTRS)

    Arutyunyan, G. M.; Nerkararyan, K. V.

    1984-01-01

    The calculation of the interband absorption coefficient was carried out in the classical case, when the frequency of light was assumed to bind two miniband subbarrier states of different bands. The influence of two dimensional Mott excitons on this absorption was studied and a comparison was made with the experiment. All of these considerations were done taking into account the photon wave vector (the phase spatial heterogeneity). The basic traits of the energy spectra of superlattice semiconductors, their kinetic and optical properties, and possible means of electromagnetic wave intensification were examined. By the density matrix method, a theory of electrical and electromagnetic properties of superlattices was suggested.

  15. Intestinal absorption and biomagnification of organochlorines

    SciTech Connect

    Gobas, F.A.P.C.; McCorquodale, J.R.; Haffner, G.D.

    1993-03-01

    Dietary uptake rates of several organochlorines from diets with different lipid contents were measured in goldfish (Carassius auratus) to investigate the mechanism of intestinal absorption and biomagnification of organic chemical. The results suggest that intestinal absorption is predominantly controlled by chemical diffusion rather than lipid cotransport. Data for chemical uptake in human infants are presented to illustrate that biomagnification is caused by the digestion of food in the gastrointestinal tract. The findings are discussed in the context of two conflicting theories for the mechanism of biomagnification, and a mechanistic model is presented for the dietary uptake and biomagnification of organicmore » chemicals in fish and mammals.« less

  16. Energy absorption of composite material and structure

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1987-01-01

    Results are presented from a joint research program on helicopter crashworthiness conducted by the U.S. Army Aerostructures Directorate and NASA Langley. Through the ongoing research program an in-depth understanding has been developed on the cause/effect relationships between material and architectural variables and the energy-absorption capability of composite material and structure. Composite materials were found to be efficient energy absorbers. Graphite/epoxy subfloor structures were more efficient energy absorbers than comparable structures fabricated from Kevlar or aluminum. An accurate method of predicting the energy-absorption capability of beams was developed.

  17. Simultaneous optimization method for absorption spectroscopy postprocessing.

    PubMed

    Simms, Jean M; An, Xinliang; Brittelle, Mack S; Ramesh, Varun; Ghandhi, Jaal B; Sanders, Scott T

    2015-05-10

    A simultaneous optimization method is proposed for absorption spectroscopy postprocessing. This method is particularly useful for thermometry measurements based on congested spectra, as commonly encountered in combustion applications of H2O absorption spectroscopy. A comparison test demonstrated that the simultaneous optimization method had greater accuracy, greater precision, and was more user-independent than the common step-wise postprocessing method previously used by the authors. The simultaneous optimization method was also used to process experimental data from an environmental chamber and a constant volume combustion chamber, producing results with errors on the order of only 1%.

  18. New Parameterization of Neutron Absorption Cross Sections

    NASA Technical Reports Server (NTRS)

    Tripathi, Ram K.; Wilson, John W.; Cucinotta, Francis A.

    1997-01-01

    Recent parameterization of absorption cross sections for any system of charged ion collisions, including proton-nucleus collisions, is extended for neutron-nucleus collisions valid from approx. 1 MeV to a few GeV, thus providing a comprehensive picture of absorption cross sections for any system of collision pairs (charged or uncharged). The parameters are associated with the physics of the problem. At lower energies, optical potential at the surface is important, and the Pauli operator plays an increasingly important role at intermediate energies. The agreement between the calculated and experimental data is better than earlier published results.

  19. Laser isotope separation by multiple photon absorption

    DOEpatents

    Robinson, C.P.; Rockwood, S.D.; Jensen, R.J.; Lyman, J.L.; Aldridge, J.P. III.

    1987-04-07

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO[sub 2] laser light may be used to highly enrich [sup 34]S in natural SF[sub 6] and [sup 11]B in natural BCl[sub 3]. 8 figs.

  20. Laser isotope separation by multiple photon absorption

    DOEpatents

    Robinson, C. Paul; Rockwood, Stephen D.; Jensen, Reed J.; Lyman, John L.; Aldridge, III, Jack P.

    1987-01-01

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.