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Sample records for neutron-gamma fields specific

  1. Workplace characterisation in mixed neutron-gamma fields, specific requirements and available methods at high-energy accelerators.

    PubMed

    Silari, Marco

    2007-01-01

    A good knowledge of the radiation field present outside the shielding of high-energy particle accelerators is very important to be able to select the type of detectors (active and/or passive) to be employed for area monitoring and the type of personal dosemeter required for estimating the doses received by individuals. Around high-energy electron and proton accelerators the radiation field is usually dominated by neutrons and photons, with minor contributions from other charged particles. Under certain circumstances, muon radiation in the forward beam direction may also be present. Neutron dosimetry and spectrometry are of primary importance to characterise the radiation field and thus to correctly evaluate personnel exposure. Starting from the beam parameters important for radiation monitoring, the paper first briefly reviews the stray radiation fields encountered around high-energy accelerators and then addresses the relevant techniques employed for their monitoring. Recent developments to increase the response of neutron measuring devices beyond 10-20 MeV are illustrated. Instruments should be correctly calibrated either in reference monoenergetic radiation fields or in a field similar to the field in which they are used (workplace calibration). The importance of the instrument calibration is discussed and available neutron calibration facilities are briefly reviewed.

  2. Dosimetry in mixed neutron-gamma fields

    SciTech Connect

    Remec, I.

    1998-04-01

    The gamma field accompanying neutrons may, in certain circumstances, play an important role in the analysis of neutron dosimetry and even in the interpretation of radiation induced steel embrittlement. At the High Flux Isotope Reactor pressure vessel the gamma induced reactions dominate the responses of {sup 237}Np and {sup 238}U dosimeters, and {sup 9}Be helium accumulation fluence monitors. The gamma induced atom displacement rate in steel is higher than corresponding neutron rate, and is the cause of ``accelerated embrittlement`` of HFIR materials. In a large body of water, adjacent to a fission plate, photofissions contribute significantly to the responses of fission monitors and need to be taken into account if the measurements are used for the qualification of the transport codes and cross-section libraries.

  3. A method to describe inelastic gamma field distribution in neutron gamma density logging.

    PubMed

    Zhang, Feng; Zhang, Quanying; Liu, Juntao; Wang, Xinguang; Wu, He; Jia, Wenbao; Ti, Yongzhou; Qiu, Fei; Zhang, Xiaoyang

    2017-08-21

    Pulsed neutron gamma density logging (NGD) is of great significance for radioprotection and density measurement in LWD, however, the current methods have difficulty in quantitative calculation and single factor analysis for the inelastic gamma field distribution. In order to clarify the NGD mechanism, a new method is developed to describe the inelastic gamma field distribution. Based on the fast-neutron scattering and gamma attenuation, the inelastic gamma field distribution is characterized by the inelastic scattering cross section, fast-neutron scattering free path, formation density and other parameters. And the contribution of formation parameters on the field distribution is quantitatively analyzed. The results shows the contribution of density attenuation is opposite to that of inelastic scattering cross section and fast-neutron scattering free path. And as the detector-spacing increases, the density attenuation gradually plays a dominant role in the gamma field distribution, which means large detector-spacing is more favorable for the density measurement. Besides, the relationship of density sensitivity and detector spacing was studied according to this gamma field distribution, therefore, the spacing of near and far gamma ray detector is determined. The research provides theoretical guidance for the tool parameter design and density determination of pulsed neutron gamma density logging technique. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Evaluation of a PIN Photodiode Detector in Neutron-Gamma Fields

    NASA Astrophysics Data System (ADS)

    Cárdenas, José Patricio N.; Campos, Letícia L.; Filho, Tufic Madi

    2011-08-01

    Semiconductor detectors are suitable for applications in radiation dosimetry in nuclear research reactors and for radiation protection purposes. The performance of these detectors depends on the quality of their semiconductor. The aim of this work was to evaluate a commercial PIN Photodiode in the neutron-gamma fields of the IEA-R1 nuclear research reactor and from an AmBe neutron source. This semiconductor was studied as a neutron detector using some types of converters to determine a dose-to-counts conversion factor to dose equivalent. The results have shown that this component may be implemented for assessing the neutron spectra in some radiation fields and in dose equivalent in radiation protection routines.

  5. ESR response of CFQ-Gd2O3 dosimeters to a mixed neutron-gamma field: Monte Carlo simulation.

    PubMed

    Hoseininaveh, M; Ranjbar, A H

    2015-11-01

    Clear fused quartz (CFQ) may be considered a suitable material for electron and gamma dose measurements using electron spin resonance (ESR) technique. Research has been ongoing to optimize the neutron capture therapy (NCT) mechanism and its effects in cancer treatment. Neutron sources of the mixed neutron-gamma field are a challenge for this treatment method. A reliable dosimetric measurement and treatment should be able to determine various components of this mixed field. In this study, the ESR response of cylindrical and spherical shells of CFQ dosimeters, filled with Gd2O3, when exposed to a thermal neutron beam, has been investigated using Monte Carlo simulation. In order to maximize the ESR response, the dimensions of the outer and inner parts of the samples have been chosen as variables, and the amount of energy deposited in the samples has been determined. The optimum size of the samples has been determined, and the capability of discriminating gamma and neutron dose in a mixed neutron-gamma field regarding the CFQ-Gd2O3 dosimeter has also been widely studied.

  6. The Application of Experimental Microdosimetry to Mixed-Field Neutron-Gamma Dosimetry

    NASA Astrophysics Data System (ADS)

    Al-Bayati, Saad Najm

    Absorbed dose distributions in lineal energy for neutrons and gamma rays were measured by using both a tissue-equivalent walled counter (TEPC) and a graphite-walled low pressure proportional counter (GPC) in the Am-Be neutron source facility at UOIT. A series of measurements were performed with the counters filled with propane-based TE gas (55.1% C3H8, 39.5% CO2 and 5.4% N2) at operating gas pressures corresponding to tissue spheres 2.0, 4.0 and 8.0 µm in diameter. The results of these measurements indicated satisfactory performance of counters to measure microdosimetric spectra extending down to event-sizes that cover the gamma component of a mixed field. The spectra and the related mean values y F and yD are compared with other similar work but with monoenergetic neutrons of different energy range, the agreement between them is good. An assessment of the performance of different size TEPC has been done. An excellent agreement between their event size spectra was found and the proton edge appears at the same position on the lineal energy scale and differences in microdosimetric parameters y F and yD is not exceeding 3%, which is in the region of counting statistics. In Am-Be neutron field, the efficiency of the TEPCs was measured to have an average value of 250 counts per µSv or equivalently about 4.17 counts per minutes per µSv/hr. This efficiency is reasonable for dose equivalent measurements but needs a long integration period. The measurements showed that the dose equivalent which depends on the measurement of energy deposition by the secondary charged particles was originated mainly from elastic collisions of the incident neutrons with hydrogen atoms. Moreover the number of events in the sensitive gas is dominated by proton recoils. A non-negligible fraction of the dose equivalent resulted from gamma

  7. Plasma driven neutron/gamma generator

    DOEpatents

    Leung, Ka-Ngo; Antolak, Arlyn

    2015-03-03

    An apparatus for the generation of neutron/gamma rays is described including a chamber which defines an ion source, said apparatus including an RF antenna positioned outside of or within the chamber. Positioned within the chamber is a target material. One or more sets of confining magnets are also provided to create a cross B magnetic field directly above the target. To generate neutrons/gamma rays, the appropriate source gas is first introduced into the chamber, the RF antenna energized and a plasma formed. A series of high voltage pulses are then applied to the target. A plasma sheath, which serves as an accelerating gap, is formed upon application of the high voltage pulse to the target. Depending upon the selected combination of source gas and target material, either neutrons or gamma rays are generated, which may be used for cargo inspection, and the like.

  8. Pulse-shape discrimination of the new plastic scintillators in neutron-gamma mixed field using fast digitizer card

    NASA Astrophysics Data System (ADS)

    Jančář, A.; Kopecký, Z.; Dressler, J.; Veškrna, M.; Matěj, Z.; Granja, C.; Solar, M.

    2015-11-01

    Recently invented plastic scintillator EJ-299-33 enables pulse-shape discrimination (PSD) and thus measurement of neutron and photon spectra in mixed fields. In this work we compare the PSD properties of EJ-299-33 plastic and the well-known NE-213 liquid scintillator in monoenergetic neutron fields generated by the Van de Graaff accelerator using the 3H(d, n)4He reaction. Pulses from the scintillators are processed by a newly developed digital measuring system employing the fast digitizer card. This card contains two AD converters connected to the measuring computer via 10 Gbps optical ethernet. The converters operate with a resolution of 12 bits and have two differential inputs with a sampling frequency 1 GHz. The resulting digital channels with different gains are merged into one composite channel with a higher digital resolution in a wide dynamic range of energies. Neutron signals are fully discriminated from gamma signals. Results are presented.

  9. Measurements of neutron distribution in neutrons-gamma-rays mixed field using imaging plate for neutron capture therapy.

    PubMed

    Tanaka, Kenichi; Endo, Satoru; Hoshi, Masaharu

    2010-01-01

    The imaging plate (IP) technique is tried to be used as a handy method to measure the spatial neutron distribution via the (157)Gd(n,gamma)(158)Gd reaction for neutron capture therapy (NCT). For this purpose, IP is set in a water phantom and irradiated in a mixed field of neutrons and gamma-rays. The Hiroshima University Radiobiological Research Accelerator is utilized for this experiment. The neutrons are moderated with 20-cm-thick D(2)O to obtain suitable neutron field for NCT. The signal for IP doped with Gd as a neutron-response enhancer is subtracted with its contribution by gamma-rays, which was estimated using IP without Gd. The gamma-ray response of Gd-doped IP to non-Gd IP is set at 1.34, the value measured for (60)Co gamma-rays, in estimating the gamma-ray contribution to Gd-doped IP signal. Then measured distribution of the (157)Gd(n,gamma)(158)Gd reaction rate agrees within 10% with the calculated value based on the method that has already been validated for its reproducibility of Au activation. However, the evaluated distribution of the (157)Gd(n,gamma)(158)Gd reaction rate is so sensitive to gamma-ray energy, e.g. the discrepancy of the (157)Gd(n,gamma)(158)Gd reaction rate between measurement and calculation becomes 30% for the photon energy change from 33keV to 1.253MeV.

  10. Development of monitoring method of spatial neutron distribution in neutrons-gamma rays mixed field using imaging plate for NCT--depression of the field.

    PubMed

    Tanaka, Kenichi; Endo, Satoru; Hoshi, Masaharu; Takada, Jun

    2011-12-01

    The degree of depression in the neutron field caused by neutron absorption in the materials of an imaging plate (IP) was investigated using MCNP-4C. Consequently, the IP doped with Gd, which reproduced the distribution of (157)Gd(n,γ)(158)Gd reaction rate in the previous study, depresses the relative distribution by about 50%. The depression for the IP in which Gd is replaced with similar amount of B atoms was estimated to be about 10%. The signal intensity for this IP is estimated to be at a similar level with that for Gd-doped IP.

  11. Dose calculation in biological samples in a mixed neutron-gamma field at the TRIGA reactor of the University of Mainz.

    PubMed

    Schmitz, Tobias; Blaickner, Matthias; Schütz, Christian; Wiehl, Norbert; Kratz, Jens V; Bassler, Niels; Holzscheiter, Michael H; Palmans, Hugo; Sharpe, Peter; Otto, Gerd; Hampel, Gabriele

    2010-10-01

    To establish Boron Neutron Capture Therapy (BNCT) for non-resectable liver metastases and for in vitro experiments at the TRIGA Mark II reactor at the University of Mainz, Germany, it is necessary to have a reliable dose monitoring system. The in vitro experiments are used to determine the relative biological effectiveness (RBE) of liver and cancer cells in our mixed neutron and gamma field. We work with alanine detectors in combination with Monte Carlo simulations, where we can measure and characterize the dose. To verify our calculations we perform neutron flux measurements using gold foil activation and pin-diodes. Material and methods. When L-α-alanine is irradiated with ionizing radiation, it forms a stable radical which can be detected by electron spin resonance (ESR) spectroscopy. The value of the ESR signal correlates to the amount of absorbed dose. The dose for each pellet is calculated using FLUKA, a multipurpose Monte Carlo transport code. The pin-diode is augmented by a lithium fluoride foil. This foil converts the neutrons into alpha and tritium particles which are products of the (7)Li(n,α)(3)H-reaction. These particles are detected by the diode and their amount correlates to the neutron fluence directly. Results and discussion. Gold foil activation and the pin-diode are reliable fluence measurement systems for the TRIGA reactor, Mainz. Alanine dosimetry of the photon field and charged particle field from secondary reactions can in principle be carried out in combination with MC-calculations for mixed radiation fields and the Hansen & Olsen alanine detector response model. With the acquired data about the background dose and charged particle spectrum, and with the acquired information of the neutron flux, we are capable of calculating the dose to the tissue. Conclusion. Monte Carlo simulation of the mixed neutron and gamma field of the TRIGA Mainz is possible in order to characterize the neutron behavior in the thermal column. Currently we also

  12. Development of MCNPX-ESUT computer code for simulation of neutron/gamma pulse height distribution

    NASA Astrophysics Data System (ADS)

    Abolfazl Hosseini, Seyed; Vosoughi, Naser; Zangian, Mehdi

    2015-05-01

    In this paper, the development of the MCNPX-ESUT (MCNPX-Energy Engineering of Sharif University of Technology) computer code for simulation of neutron/gamma pulse height distribution is reported. Since liquid organic scintillators like NE-213 are well suited and routinely used for spectrometry in mixed neutron/gamma fields, this type of detectors is selected for simulation in the present study. The proposed algorithm for simulation includes four main steps. The first step is the modeling of the neutron/gamma particle transport and their interactions with the materials in the environment and detector volume. In the second step, the number of scintillation photons due to charged particles such as electrons, alphas, protons and carbon nuclei in the scintillator material is calculated. In the third step, the transport of scintillation photons in the scintillator and lightguide is simulated. Finally, the resolution corresponding to the experiment is considered in the last step of the simulation. Unlike the similar computer codes like SCINFUL, NRESP7 and PHRESP, the developed computer code is applicable to both neutron and gamma sources. Hence, the discrimination of neutron and gamma in the mixed fields may be performed using the MCNPX-ESUT computer code. The main feature of MCNPX-ESUT computer code is that the neutron/gamma pulse height simulation may be performed without needing any sort of post processing. In the present study, the pulse height distributions due to a monoenergetic neutron/gamma source in NE-213 detector using MCNPX-ESUT computer code is simulated. The simulated neutron pulse height distributions are validated through comparing with experimental data (Gohil et al. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 664 (2012) 304-309.) and the results obtained from similar computer codes like SCINFUL, NRESP7 and Geant4. The simulated gamma pulse height distribution for a 137Cs

  13. Neutron/Gamma-ray discrimination through measures of fit

    SciTech Connect

    Amiri, Moslem; Prenosil, Vaclav; Cvachovec, Frantisek

    2015-07-01

    Statistical tests and their underlying measures of fit can be utilized to separate neutron/gamma-ray pulses in a mixed radiation field. In this article, first the application of a sample statistical test is explained. Fit measurement-based methods require true pulse shapes to be used as reference for discrimination. This requirement makes practical implementation of these methods difficult; typically another discrimination approach should be employed to capture samples of neutrons and gamma-rays before running the fit-based technique. In this article, we also propose a technique to eliminate this requirement. These approaches are applied to several sets of mixed neutron and gamma-ray pulses obtained through different digitizers using stilbene scintillator in order to analyze them and measure their discrimination quality. (authors)

  14. HotSpotter? Neutron/Gamma Detector

    SciTech Connect

    Bell, Z.W.

    2003-04-01

    The HotSpotter{trademark} Neutron/Gamma Detector combines in a single detecting module high sensitivity to gamma rays up to 3 MeV and sensitivity to neutrons. Using a 15 mm cubic CdWO{sub 4} (cadmium tungstate) crystal mounted on a 25 mm photomultiplier, the instrument realizes a factor of 5 increased photopeak efficiency over NaI(Tl) at 1 MeV, and a factor of 2 improvement over CsI(Tl). The addition of a 0.5 mm layer of {sup 10}B- impregnated epoxy covering the crystal provides neutron sensitivity without sacrificing gamma ray spectroscopic characteristics. Neutrons are detected by the presence of the 478 keV gamma from the {sup 10}B(n,{alpha}){sup 7}Li* reaction. In this paper, we describe the electronics and software of the instrument, and some of its characteristics.

  15. The neutron-gamma Feynman variance to mean approach: Gamma detection and total neutron-gamma detection (theory and practice)

    NASA Astrophysics Data System (ADS)

    Chernikova, Dina; Axell, Kåre; Avdic, Senada; Pázsit, Imre; Nordlund, Anders; Allard, Stefan

    2015-05-01

    Two versions of the neutron-gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron-gamma detection, respectively, are derived and compared in this paper. The new formulas have particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron-gamma detection Feynman-Y expression corresponds to a situation where no discrimination is made between neutrons and gamma particles. The gamma variance to mean formulas are useful when a detector of only gamma radiation is used or when working with a combined neutron-gamma detector at high count rates. The theoretical derivation is based on the Chapman-Kolmogorov equation with the inclusion of general reactions and corresponding intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a 252Cf-source. In addition, the variance to mean ratios, neutron, gamma and total neutron-gamma are evaluated experimentally for a weak 252Cf neutron-gamma source, a 137Cs random gamma source and a 22Na correlated gamma source. Due to the focus being on the possibility of using neutron-gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-alpha formulas.

  16. MCNP capabilities at the dawn of the 21st century: Neutron-gamma applications

    SciTech Connect

    Selcow, E.C.; McKinney, G.W.

    2000-10-01

    The Los Alamos National Laboratory Monte Carlo N-Particle radiation transport code, MCNP, has become an international standard for a wide spectrum of neutron-gamma radiation transport applications. These include nuclear criticality safety, radiation shielding, nuclear safeguards, nuclear well-logging, fission and fusion reactor design, accelerator target design, detector design and analysis, health physics, medical radiation therapy and imaging, radiography, decontamination and decommissioning, and waste storage and disposal. The latest version of the code, MCNP4C, was released to the Radiation Safety Information Computational Center (RSICC) in February 2000.This paper described the new features and capabilities of the code, and discusses the specific applicability to neutron-gamma problems. We will also discuss the future directions for MCNP code development, including rewriting the code in Fortran 90.

  17. Using singular value decomposition for neutron-gamma discrimination

    NASA Astrophysics Data System (ADS)

    Linczuk, Maciej; Korolczuk, Stefan; Cieszewski, Radosław

    2015-09-01

    A Digital Signal Processing method for Neutron Gamma Discrimination [1] is described in this paper. A Singular Value Decomposition (SVD) was used for estimation noiseless signal shape. Based on this shape, detection method was introduced. This method uses projection operation into signal and noise subspace and Signal to Noise Ratio estimation. This method was compared with another one proposed by [2]. Booth method was implemented in MATLAB. Computation was done on signals from scintillators. Data acquisition was dome with high quality hardware. The Neutron Gamma Discrimination algorithm operate on digital samples from ADC converter. Hardware used for data acquisition in this this paper was described in [3]. On the end, the results of this two methods was presented and compared. The signal model in this methods assume additional, white, Gaussian noise.

  18. Neutron-gamma discrimination with UGAB scintillator using zero-crossing method.

    PubMed

    Divani-Vais, N; Bayat, E; Firoozabadi, M M; Ghal-Eh, N

    2013-01-01

    The new-type scintillator, Ultima Gold Alpha-Beta (UGAB), was studied for its neutron-gamma discrimination capability. The figure-of-merit and peak-to-valley values for the neutron-gamma discrimination spectra of UGAB scintillator when exposed to (241)Am-Be neutron source were presented. The results show that this new-type scintillator can efficiently be used in neutron-gamma discrimination experiments.

  19. Digital neutron-gamma discrimination with scintillators: An innovative approach

    NASA Astrophysics Data System (ADS)

    Jamili, S.; Bayat, E.; Ghal-Eh, N.

    2017-03-01

    In this paper, a digital neutron-gamma discrimination (DNGD) method with an NE213 scintillator has been proposed in which the anode pulse is divided into two different pulses, one representing the amplitude and the other characterizes the DNGD. Then the two pulses are summed up after travelling through delay and mixer circuits to form an input pulse for sampling in analog-to-digital converter (ADC). The discrimination tests have been performed with an 8-bit digital storage oscilloscope (DSO) as ADC and 241Am-Be neutron source, whereas the Fourier method has been used to derive the discrimination characteristic. The results confirm the fast performance and efficiency of proposed method.

  20. Integrated neutron/gamma-ray portal monitors for nuclear safeguards

    SciTech Connect

    Fehlau, P.E. )

    1994-08-01

    Radiation monitoring is one nuclear-safeguards measure used to protect against the theft of special nuclear materials (SNM) by pedestrians departing from SNM access areas. The integrated neutron/gamma-ray portal monitor is an ideal radiation monitor for the task when the SNM is plutonium. It achieves high sensitivity for detecting both bare and shielded plutonium by combining two types of radiation detector. One type is a neutron-chamber detector, comprising a large, hollow, neutron moderator that contains a single thermal-neutron proportional counter. The entrance wall of each chamber is thin to admit slow neutrons from plutonium contained in a moderating shield, while the other walls are thick to moderate fast neutrons from bare or lead-shielded plutonium so that they can be detected. The other type of detector is a plastic scintillator that is primarily for detecting gamma rays from small amounts of unshielded plutonium. The two types of detector are easily integrated by making scintillators part of the thick back wall of each neutron chamber or by inserting them into each chamber void. The authors compared the influence of the two methods of integration on detecting neutrons and gamma rays, and they examined the effectiveness of other design factors and the methods for signal detection as well.

  1. Integrated neutron/gamma-ray portal monitors for nuclear safeguards

    SciTech Connect

    Fehlau, P.E.

    1993-09-01

    Radiation monitoring is one nuclear-safeguards measure used to protect against the theft of special nuclear materials (SNM) by pedestrians departing from SNM access areas. The integrated neutron/gamma-ray portal monitor is an ideal radiation monitor for the task when the SNM is plutonium. It achieves high sensitivity for detecting both bare and shielded plutonium by combining two types of radiation detector. One type is a neutron-chamber detector, comprising a large, hollow, neutron moderator that contains a single thermal-neutron proportional counter. The entrance wall of each chamber is thin to admit slow neutrons from plutonium contained in a moderating shield, while the other walls are thick to moderate fast neutrons from bare or lead-shielded plutonium so that they can be detected. The other type of detector is a plastic scintillator that is primarily for detecting gamma rays from small amounts of unshielded plutonium. The two types of detector are easily integrated by making scintillators part of the thick back wall of each neutron chamber or by inserting them into each chamber void. We compared the influence of the two methods of integration on detecting neutrons and gamma rays, and we examined the effectiveness of other design factors and the methods for signal detection as well.

  2. Integrated neutron/gamma-ray portal monitors for nuclear safeguards

    NASA Astrophysics Data System (ADS)

    Fehlau, Paul E.

    1994-08-01

    Radiation monitoring is one nuclear-safeguards measure used to protect against the theft of special nuclear materials (SNM) by pedestrians departing from SNM access areas. The integrated neutron/gamma-ray portal monitor is an ideal radiation monitor for the task when the SNM is plutonium. It achieves high sensitivity for detecting both bare and shielded plutonium by combining two types of radiation detector. One type is a neutron-chamber detector, comprising a large, hollow, neutron moderator that contains a single thermal-neutron proportional counter. The entrance wall of each chamber is thin to admit slow neutrons from plutonium contained in a moderating shield, while the other walls are thick to moderate fast neutrons from bare or lead-shielded plutonium so that they can be detected. The other type of detector is a plastic scintillator that is primarily for detecting gamma rays from small amounts of unshielded plutonium. The two types of detector are easily integrated by making scintillators part of the thick back wall of each neutron chamber or by inserting them into each chamber void. We compared the influence of the two methods of integration on detecting neutrons and gamma rays, and we examined the effectiveness of other design factors and the methods for signal detection as well.

  3. Application of Nonnegative Tensor Factorization for neutron-gamma discrimination of Monte Carlo simulated fission chamber's output signals

    NASA Astrophysics Data System (ADS)

    Laassiri, Mounia; Hamzaoui, El-Mehdi; Cherkaoui El Moursli, Rajaa

    For efficient exploitation of research reactors, it is important to discern neutron flux distribution inside the reactor with the best possible precision. For this reason, fission and ionization chambers are used to measure the neutron field. In these arrays, the sequences of the neutron interaction points in the fission chamber can correctly be identified in order to obtain true neutron energies emitted by nuclei of interest. However, together with the neutrons, gamma-rays are also emitted from nuclei and thereby affect neutron spectra. The originality of this study consists in the application of tensor based blind source separation methods to extract independent components from signals recorded at the fission chamber preamplifier's output. The objective is to achieve software neutron-gamma discrimination using Nonnegative Tensor Factorization tools. For reasons of nuclear safety, we first simulate the neutron flux inside the TRIGA Mark II Reactor using Monte Carlo methods under Geant4 platform linked to Garfield++. Geant4 simulations allow the fission chamber construction whereas linking the model to Garfield++ permits to simulate drift parameters from the ionization of the filling gas, which is not possible otherwise.

  4. Development of a New Fast Neutron/Gamma Spectrometer Array Using CLYC

    NASA Astrophysics Data System (ADS)

    D'Olympia, Nathan; Chowdhury, Partha; Lister, Christopher

    2013-10-01

    Neutron physics has long suffered from a lack of detectors that provide spectroscopic information without the need for inefficient time-of-flight techniques. Any headway made towards a spectrometer with good energy resolution and neutron/gamma pulse-shape discrimination represents an important step forward in the field. Recent investigations at the University of Massachusetts Lowell with Cs2LiYCl6 (CLYC) scintillators have demonstrated their potential for direct pulse-height measurements via the 35Cl(n,p) reaction. From this work, it was recognized that CLYC could be optimized for fast neutron detection by growing 6Li-depleted crystals to suppress the overwhelming thermal neutron response. A project is now underway to develop a versatile array of 16 1'' ×1'' 6Li-depleted CLYC detectors for measurements in nuclear astrophysics, reactor data, homeland security, and nuclear structure. Initial measurements of interest include prompt fission neutrons, β-delayed neutrons, and scattering cross sections. Characterizations of the neutron and gamma-ray response for the first two detectors of the array are being carried out at various facilities with both mono-energetic and continuous fast neutron beams. Supported by the U.S. Department of Energy under grant #DE-FG02-94ER40848.

  5. Interactions between endothelial cells and T cells modulate responses to mixed neutron/gamma radiation.

    PubMed

    Cary, Lynnette H; Noutai, Daniel; Salber, Rudolph E; Williams, Margaret S; Ngudiankama, Barbara F; Whitnall, Mark H

    2014-06-01

    Detonation of an improvised nuclear device near a population center would cause significant casualties from the acute radiation syndrome (ARS) due to exposure to mixed neutron/gamma fields (MF). The pathophysiology of ARS involves inflammation, microvascular damage and alterations in immune function. Interactions between endothelial cells (EC) and hematopoietic cells are important not only for regulating immune cell traffic and function, but also for providing the microenvironment that controls survival, differentiation and migration of hematopoietic stem and progenitor cells in blood-forming tissues. Endothelial cells/leukocyte interactions also influence tumor progression and the results of anticancer therapies. In this study, we hypothesized that irradiation of endothelial cells would modulate their effects on hematopoietic cells and vice versa. Human umbilical vein endothelial cells (HUVEC) and immortalized T lymphocytes (Jurkat cells) were cultured individually and in co-culture after exposure to mixed fields. Effects of nonirradiated cells were compared to effects of irradiated cells and alterations in signaling pathways were determined. Mitogen-activated protein kinases (MAPKs) p38 and p44/42 (ERK1/2) in HUVEC exhibited higher levels of phosphorylated protein after exposure to mixed field radiation. IL-6, IL-8, G-CSF, platelet derived growth factor (PDGF) and angiopoietin 2 (ANG2) protein expression were upregulated in HUVEC by exposure to mixed field radiation. PCR arrays using HUVEC mRNA revealed alterations in gene expression after exposure to mixed fields and/or co-culture with Jurkat cells. The presence of HUVEC also influenced the function of Jurkat cells. Nonirradiated Jurkat cells showed an increase in proliferation when co-cultured with nonirradiated HUVEC, and a decrease in proliferation when co-cultured with irradiated HUVEC. Additionally, nonirradiated Jurkat cells incubated in media from irradiated HUVEC exhibited upregulation of activated

  6. Triplet harvesting plastic scintillators with neutron-gamma pulse shape discrimination

    NASA Astrophysics Data System (ADS)

    van Loef, Edgar V.; Feng, Patrick; Markosyan, Gary; Shirwadkar, Urmila; Doty, Patrick; Shah, Kanai

    2014-09-01

    In this paper we report on plastic scintillators that contain organometallic iridium compounds as triplet harvesting complexes for neutron-gamma pulse shape discrimination (PSD). Our results show that these plastic scintillators have a relatively high light output (higher than BGO) and exhibit very good neutron-gamma PSD with a Figure-of-Merit of ≥ 2.0 at 2.5 MeVee cut-off energy. Under X-ray excitation, the radioluminescence spectrum exhibits a broad band between 400 and 650 nm peaking at 470 nm which is well-matched to bialkali photomultiplier tubes and UV-enhanced photodiodes. The scintillation decay due to Ir3+ luminescence is of the order of 1 us.

  7. Using a Borated Panel to Form a Dual Neutron-Gamma Detector

    SciTech Connect

    Scott Wilde; Raymond Keegan

    2008-06-20

    A borated polyethylene plane placed between a neutron source and a gamma spectrometer is used to form a dual neutron-gamma detection system. The polyethylene thermalizes the source neutrons so that they are captured by {sup 10}B to produce a flux of 478 keV gamma-rays that radiate from the plane. This results in a buildup of count rate in the detector over that from a disk of the same diameter as the detector crystal (same thickness as the panel). Radiation portal systems are a potential application of this technique.

  8. ICF ignition capsule neutron, gamma ray, and high energy x-ray images

    NASA Astrophysics Data System (ADS)

    Bradley, P. A.; Wilson, D. C.; Swenson, F. J.; Morgan, G. L.

    2003-03-01

    Post-processed total neutron, RIF neutron, gamma-ray, and x-ray images from 2D LASNEX calculations of burning ignition capsules are presented. The capsules have yields ranging from tens of kilojoules (failures) to over 16 MJ (ignition), and their implosion symmetry ranges from prolate (flattest at the hohlraum equator) to oblate (flattest towards the laser entrance hole). The simulated total neutron images emphasize regions of high DT density and temperature; the reaction-in-flight neutrons emphasize regions of high DT density; the gamma rays emphasize regions of high shell density; and the high energy x rays (>10 keV) emphasize regions of high temperature.

  9. Neutron-gamma discrimination employing pattern recognition of the signal from liquid scintillator

    NASA Astrophysics Data System (ADS)

    Kamada, Kohji; Enokido, Uhji; Ogawa, Seiji

    1999-05-01

    A pattern recognition method was applied to the neutron-gamma discrimination of the pulses from the liquid scintillator, NE-213. The circuit for the discrimination is composed of A/D converter, fast SCA, memory control circuit, two digital delay lines and two buffer memories. All components are packed on a small circuit board and are installed into a personal computer. Experiments using a weak 252Cf n-γ source were undertaken to test the feasibility of the circuit. The circuit is of very easy adjustment and, at the same time, of very economical price when compared with usual discrimination circuits, such as the TAC system.

  10. Accuracy and borehole influences in pulsed neutron gamma density logging while drilling.

    PubMed

    Yu, Huawei; Sun, Jianmeng; Wang, Jiaxin; Gardner, Robin P

    2011-09-01

    A new pulsed neutron gamma density (NGD) logging has been developed to replace radioactive chemical sources in oil logging tools. The present paper describes studies of near and far density measurement accuracy of NGD logging at two spacings and the borehole influences using Monte-Carlo simulation. The results show that the accuracy of near density is not as good as far density. It is difficult to correct this for borehole effects by using conventional methods because both near and far density measurement is significantly sensitive to standoffs and mud properties.

  11. Investigation about decoupling capacitors of PMT voltage divider effects on neutron-gamma discrimination

    SciTech Connect

    Divani, Nazila Firoozabadi, Mohammad M.; Bayat, Esmail

    2014-11-24

    Scintillators are almost used in any nuclear laboratory. These detectors combine of scintillation materials, PMT and a voltage divider. Voltage dividers are different in resistive ladder design. But the effect of decoupling capacitors and damping resistors haven’t discussed yet. In this paper at first a good equilibrium circuit designed for PMT, and it was used for investigating about capacitors and resistors in much manner. Results show that decoupling capacitors have great effect on PMT output pulses. In this research, it was tried to investigate the effect of Capacitor’s value and places on PMT voltage divider in Neutron-Gamma discrimination capability. Therefore, the voltage divider circuit for R329-02 Hamamatsu PMT was made and Zero Cross method used for neutron-gamma discrimination. The neutron source was a 20Ci Am-Be. Anode and Dynode pulses and discrimination spectrum were saved. The results showed that the pulse height and discrimination quality change with the value and setting of capacitors.

  12. Improved neutron-gamma discrimination for a 3He neutron detector using subspace learning methods

    NASA Astrophysics Data System (ADS)

    Wang, C. L.; Funk, L. L.; Riedel, R. A.; Berry, K. D.

    2017-05-01

    3He gas based neutron Linear-Position-Sensitive Detectors (LPSDs) have been used for many neutron scattering instruments. Traditional Pulse-height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (NGD ratio) on the order of 105-106. The NGD ratios of 3He detectors need to be improved for even better scientific results from neutron scattering. Digital Signal Processing (DSP) analyses of waveforms were proposed for obtaining better NGD ratios, based on features extracted from rise-time, pulse amplitude, charge integration, a simplified Wiener filter, and the cross-correlation between individual and template waveforms of neutron and gamma events. Fisher Linear Discriminant Analysis (FLDA) and three Multivariate Analyses (MVAs) of the features were performed. The NGD ratios are improved by about 102-103 times compared with the traditional PHA method. Our results indicate the NGD capabilities of 3He tube detectors can be significantly improved with subspace-learning based methods, which may result in a reduced data-collection time and better data quality for further data reduction.

  13. Improved neutron-gamma discrimination for a 3He neutron detector using subspace learning methods

    DOE PAGES

    Wang, C. L.; Funk, L. L.; Riedel, R. A.; ...

    2017-02-10

    3He gas based neutron linear-position-sensitive detectors (LPSDs) have been applied for many neutron scattering instruments. Traditional Pulse-Height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio on the orders of 105-106. The NGD ratios of 3He detectors need to be improved for even better scientific results from neutron scattering. Digital Signal Processing (DSP) analyses of waveforms were proposed for obtaining better NGD ratios, based on features extracted from rise-time, pulse amplitude, charge integration, a simplified Wiener filter, and the cross-correlation between individual and template waveforms of neutron and gamma events. Fisher linear discriminant analysis (FLDA) and threemore » multivariate analyses (MVAs) of the features were performed. The NGD ratios are improved by about 102-103 times compared with the traditional PHA method. Finally, our results indicate the NGD capabilities of 3He tube detectors can be significantly improved with subspace-learning based methods, which may result in a reduced data-collection time and better data quality for further data reduction.« less

  14. Fast-neutron/gamma-ray radiography scanner for the detection of contraband in air cargo containers

    NASA Astrophysics Data System (ADS)

    Eberhardt, J.; Liu, Y.; Rainey, S.; Roach, G.; Sowerby, B.; Stevens, R.; Tickner, J.

    2006-05-01

    There is a worldwide need for efficient inspection of cargo containers at airports, seaports and road border crossings. The main objectives are the detection of contraband such as illicit drugs, explosives and weapons. Due to the large volume of cargo passing through Australia's airports every day, it is critical that any scanning system should be capable of working on unpacked or consolidated cargo, taking at most 1-2 minutes per container. CSIRO has developed a fast-neutron/gamma-ray radiography (FNGR) method for the rapid screening of air freight. By combining radiographs obtained using 14 MeV neutrons and 60Co gamma-rays, high resolution images showing both density and material composition are obtained. A near full-scale prototype scanner has been successfully tested in the laboratory. With the support of the Australian Customs Service, a full-scale scanner has recently been installed and commissioned at Brisbane International Airport.

  15. Fast neutron-gamma discrimination on neutron emission profile measurement on JT-60U

    SciTech Connect

    Ishii, K.; Okamoto, A.; Kitajima, S.; Sasao, M.; Shinohara, K.; Ishikawa, M.; Baba, M.; Isobe, M.

    2010-10-15

    A digital signal processing (DSP) system is applied to stilbene scintillation detectors of the multichannel neutron emission profile monitor in JT-60U. Automatic analysis of the neutron-{gamma} pulse shape discrimination is a key issue to diminish the processing time in the DSP system, and it has been applied using the two-dimensional (2D) map. Linear discriminant function is used to determine the dividing line between neutron events and {gamma}-ray events on a 2D map. In order to verify the validity of the dividing line determination, the pulse shape discrimination quality is evaluated. As a result, the {gamma}-ray contamination in most of the beam heating phase was negligible compared with the statistical error with 10 ms time resolution.

  16. Development of a digital method for neutron/gamma-ray discrimination based on matched filtering

    NASA Astrophysics Data System (ADS)

    Korolczuk, S.; Linczuk, M.; Romaniuk, R.; Zychor, I.

    2016-09-01

    Neutron/gamma-ray discrimination is crucial for measurements with detectors sensitive to both neutron and gamma-ray radiation. Different techniques to discriminate between neutrons and gamma-rays based on pulse shape analysis are widely used in many applications, e.g., homeland security, radiation dosimetry, environmental monitoring, fusion experiments, nuclear spectroscopy. A common requirement is to improve a radiation detection level with a high detection reliability. Modern electronic components, such as high speed analog to digital converters and powerful programmable digital circuits for signal processing, allow us to develop a fully digital measurement system. With this solution it is possible to optimize digital signal processing algorithms without changing any electronic components in an acquisition signal path. We report on results obtained with a digital acquisition system DNG@NCBJ designed at the National Centre for Nuclear Research. A 2'' × 2'' EJ309 liquid scintillator was used to register mixed neutron and gamma-ray radiation from PuBe sources. A dedicated algorithm for pulse shape discrimination, based on real-time filtering, was developed and implemented in hardware.

  17. Novel deployment of elpasolites as a dual neutron / gamma- ray directional detector

    NASA Astrophysics Data System (ADS)

    Guckes, Amber

    (FOM) of 2.3. An array of three CLYC detectors was assembled for the purpose of directional neutron / gamma-ray detection. The intrinsic peak efficiency of CLYC detectors was evaluated. The three-CLYC detector array was deployed for directional measurements with a single gamma-ray 137Cs source, two gamma-ray sources of 137Cs and 60Co isotopes and a thermal neutron source designed using a 239PuBe neutron source supplied with a polyethylene moderator. Measurements were carried out using sources located in the longitude and latitude planes over the angles from 0° to 360°. The measured data were processed through a maximum likelihood estimation algorithm providing a possible direction for which the radioactive source in each case was positioned. The estimated directions were close if not exact matches for the actual directions to the radioactive source. The largest discrepancy in direction produced by the algorithm was approximately 11%. However, it was hypothesized that this percent error can be decreased by homogenizing the directional detection system to consist of scintillators of the same size and quality, identical photomultiplier tubes and identical aluminum housings. The feasibility of this hypothesis to decrease the percent error was confirmed by the zero percent error achieved in the directional measurements produced in the computational study utilizing a homogenous directional detection system. The results of computational and experimental studies completed within this research project provide means to propose the array of three CLYC scintillators as an efficient dual neutron / gamma-ray directional detector.

  18. Improvement of Neutron/gamma Field Evaluation for Restart of Jmtr

    NASA Astrophysics Data System (ADS)

    Nagao, Yoshiharu; Niimi, Motoji; Kawamura, Hiroshi; Iguchi, Tetsuo

    2009-08-01

    The calculated neutron flux/fluence was verified against measurements of irradiated fluence monitors. With regard to gamma dose, calculated gamma heating rates were verified against measurements of the nuclear heating evaluation capsule which was developed in order to measure the nuclear heating rate. It was confirmed that the calculated fast and thermal neutron flux/fluence agreed with measurements within ±10%, ±30%, respectively, and the calculated gamma dose agreed within -3 ~ +21%. As the results of sensitive analysis, it was confirmed that difference of thermal S(α,β) libraries was not did not have effect on the evaluation of thermal neutron fluxes.

  19. Digitized two-parameter spectrometer for neutron-gamma mixed field

    SciTech Connect

    Matej, Z.; Cvachovec, J.; Prenosil, V.; Cvachovec, F.; Zaritski, S.

    2011-07-01

    This paper shows the results of digital processing of output pulses from combined photon-neutron detector using a commercially available digitizer ACQUIRIS DP 210. The advantage of digital processing is reduction of the apparatus in weight and size, acceleration of measurement, and increased resistance to pile-up of pulses. The neutron and photon spectrum of radionuclide source {sup 252}Cf is presented. (authors)

  20. Fast specific field detection of RHDVb.

    PubMed

    Dalton, K P; Nicieza, I; Podadera, A; de Llano, D; Martin Alonso, J M; de Los Toyos, J R; García Ocaña, M; Vázquez-Villa, F; Velasco, B; Landeta, O; Parra, F

    2017-02-28

    This work describes a simple and rapid test for field detection of the emerging rabbit pathogen RHDVb. The assay is specific for RHDVb, showing no cross-reactivity with other RHDV types giving a specific result in under 10 min using rabbit liquid exudates or liver homogenate samples taken at necropsy.

  1. Improved neutron-gamma discrimination for a 6Li-glass neutron detector using digital signal analysis methods

    DOE PAGES

    Wang, Cai -Lin; Riedel, Richard A.

    2016-01-14

    A 6Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at SNS. Traditional pulse-height analysis (PHA) for neutron-gamma discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 104. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, five digital signal analysis methods of individual waveforms from PMTs were proposed using: i). pulse-amplitude histogram; ii). power spectrum analysis combined with the maximum pulse amplitude; iii). two event parameters (a1, b0) obtained from Wiener filter; iv). an effective amplitude (m)more » obtained from an adaptive least-mean-square (LMS) filter; and v). a cross-correlation (CC) coefficient between an individual waveform and a reference. The NGD ratios can be 1-102 times those from traditional PHA method. A brighter scintillator GS2 has better NGD ratio than GS20, but lower neutron detection efficiency. The ultimate NGD ratio is related to the ambient, high-energy background events. Moreover, our results indicate the NGD capability of neutron Anger cameras can be improved using digital signal analysis methods and brighter neutron scintillators.« less

  2. Improved neutron-gamma discrimination for a 6Li-glass neutron detector using digital signal analysis methods

    SciTech Connect

    Wang, Cai -Lin; Riedel, Richard A.

    2016-01-14

    A 6Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at SNS. Traditional pulse-height analysis (PHA) for neutron-gamma discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 104. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, five digital signal analysis methods of individual waveforms from PMTs were proposed using: i). pulse-amplitude histogram; ii). power spectrum analysis combined with the maximum pulse amplitude; iii). two event parameters (a1, b0) obtained from Wiener filter; iv). an effective amplitude (m) obtained from an adaptive least-mean-square (LMS) filter; and v). a cross-correlation (CC) coefficient between an individual waveform and a reference. The NGD ratios can be 1-102 times those from traditional PHA method. A brighter scintillator GS2 has better NGD ratio than GS20, but lower neutron detection efficiency. The ultimate NGD ratio is related to the ambient, high-energy background events. Moreover, our results indicate the NGD capability of neutron Anger cameras can be improved using digital signal analysis methods and brighter neutron scintillators.

  3. Improved neutron-gamma discrimination for a {sup 6}Li-glass neutron detector using digital signal analysis methods

    SciTech Connect

    Wang, C. L. Riedel, R. A.

    2016-01-15

    A {sup 6}Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at Spallation Neutron Source. Traditional Pulse-Height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 10{sup 4}. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, six digital signal analysis methods of individual waveforms acquired from photomultiplier tubes were proposed using (i) charge integration, (ii) pulse-amplitude histograms, (iii) power spectrum analysis combined with the maximum pulse-amplitude, (iv) two event parameters (a{sub 1}, b{sub 0}) obtained from a Wiener filter, (v) an effective amplitude (m) obtained from an adaptive least-mean-square filter, and (vi) a cross-correlation coefficient between individual and reference waveforms. The NGD ratios are about 70 times those from the traditional PHA method. Our results indicate the NGD capabilities of neutron Anger cameras based on GS20 scintillators can be significantly improved with digital signal analysis methods.

  4. Improved neutron-gamma discrimination for a 6Li-glass neutron detector using digital signal analysis methods

    NASA Astrophysics Data System (ADS)

    Wang, C. L.; Riedel, R. A.

    2016-01-01

    A 6Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at Spallation Neutron Source. Traditional Pulse-Height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 104. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, six digital signal analysis methods of individual waveforms acquired from photomultiplier tubes were proposed using (i) charge integration, (ii) pulse-amplitude histograms, (iii) power spectrum analysis combined with the maximum pulse-amplitude, (iv) two event parameters (a1, b0) obtained from a Wiener filter, (v) an effective amplitude (m) obtained from an adaptive least-mean-square filter, and (vi) a cross-correlation coefficient between individual and reference waveforms. The NGD ratios are about 70 times those from the traditional PHA method. Our results indicate the NGD capabilities of neutron Anger cameras based on GS20 scintillators can be significantly improved with digital signal analysis methods.

  5. Study of sampling rate influence on neutron-gamma discrimination with stilbene coupled to a silicon photomultiplier.

    PubMed

    Zhang, Jinglong; Moore, Michael E; Wang, Zhonghai; Rong, Zhou; Yang, Chaowen; Hayward, Jason P

    2017-10-01

    Choosing a digitizer with an appropriate sampling rate is often a trade-off between performance and economy. The influence of sampling rates on the neutron-gamma Pulse Shape Discrimination (PSD) with a solid stilbene scintillator coupled to a Silicon Photomultiplier was investigated in this work. Sampling rates from 125MSPS to 2GSPS from a 10-bit digitizer were used to collect detector pulses produced by the interactions of a Cf-252 source. Due to the decreased signal-to-noise ratio (SNR), the PSD performance degraded with reduced sampling rates. The reason of PSD performance degradation was discussed. Then, an efficient combination of filtering and digital signal processing (DSP) was then applied to suppress the timing noise and electronic background noise. The results demonstrate an improved PSD performance especially at low sampling rates, down to 125MSPS. Using filtering and DSP, the ascribed Figure of Merit (FOM) at 125keVee (± 10keVee) increased from 0.95 to 1.02 at 125MSPS. At 300keVee and above, all the FOMs are better than 2.00. Our study suggests that 250MSPS is a good enough sampling rate for neutron-gamma discrimination in this system in order to be sensitive to neutrons at and above ~ 125keVee. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The field theory of specific heat

    NASA Astrophysics Data System (ADS)

    Gusev, Yu. V.

    2016-01-01

    Finite temperature quantum field theory in the heat kernel method is used to study the heat capacity of condensed matter. The lattice heat is treated à la P. Debye as energy of the elastic (sound) waves. The dimensionless functional of free energy is re-derived with a cut-off parameter and used to obtain the specific heat of crystal lattices. The new dimensionless thermodynamical variable is formed as Planck's inverse temperature divided by the lattice constant. The dimensionless constant, universal for the class of crystal lattices, which determines the low temperature region of molar specific heat, is introduced and tested with the data for diamond lattice crystals. The low temperature asymptotics of specific heat is found to be the fourth power in temperature instead of the cubic power law of the Debye theory. Experimental data for the carbon group elements (silicon, germanium) and other materials decisively confirm the quartic law. The true low temperature regime of specific heat is defined by the surface heat, therefore, it depends on the geometrical characteristics of the body, while the absolute zero temperature limit is geometrically forbidden. The limit on the growth of specific heat at temperatures close to critical points, known as the Dulong-Petit law, appears from the lattice constant cut-off. Its value depends on the lattice type and it is the same for materials with the same crystal lattice. The Dulong-Petit values of compounds are equal to those of elements with the same crystal lattice type, if one mole of solid state matter were taken as the Avogadro number of the composing atoms. Thus, the Neumann-Kopp law is valid only in some special cases.

  7. Global and site specific multimedia (field) studies

    SciTech Connect

    Cutshall, N.H.; Guerin, M.R.

    1987-01-01

    Experience with radioactive fallout, with organic contaminants and with heavy metals has amply demonstrated that cross-media transfers are common and that understanding the transport, cycling, and fate of these contaminants requires a multimedia approach. Nonetheless, pollutants with similar physical and chemical attributes may follow markedly different pathways. The frequency of exceptions to predictions based on simplistic models is also sufficient to show that direct investigation of environmental contamination is essential to confirm validity of models used for conceptualizing a problem or for control. Modeling based on multimedia premises and regulatory controls that encompass multimedia considerations are challenged by a dilemma, however. First, the development of multimedia models or regulatory frameworks represents simplification and generalization. This is true for several reasons: (1) inadequate understanding of physical and environmental factors which control specific cross-media transfer; (2) the absence of specific data on certain multimedia pollutant concentrations; (3) even the most powerful computers do not have sufficient speed and capacity to deal with the known complexities of natural systems. On the other hand, for contaminants such as mercury, it may be necessary to include great detail; the overall distribution in the environment may be less important than the rate of some minor process. With sufficient experience and good judgment of what can be ignored, the simplifications and generalizations can be made. For the present, and for the foreseeable future, however, they absolutely must be accompanied by thorough field validation and monitoring.

  8. An improved numerical method to compute neutron/gamma deexcitation cascades starting from a high spin state

    DOE PAGES

    Regnier, D.; Litaize, O.; Serot, O.

    2015-12-23

    Numerous nuclear processes involve the deexcitation of a compound nucleus through the emission of several neutrons, gamma-rays and/or conversion electrons. The characteristics of such a deexcitation are commonly derived from a total statistical framework often called “Hauser–Feshbach” method. In this work, we highlight a numerical limitation of this kind of method in the case of the deexcitation of a high spin initial state. To circumvent this issue, an improved technique called the Fluctuating Structure Properties (FSP) method is presented. Two FSP algorithms are derived and benchmarked on the calculation of the total radiative width for a thermal neutron capture onmore » 238U. We compare the standard method with these FSP algorithms for the prediction of particle multiplicities in the deexcitation of a high spin level of 143Ba. The gamma multiplicity turns out to be very sensitive to the numerical method. The bias between the two techniques can reach 1.5 γγ/cascade. Lastly, the uncertainty of these calculations coming from the lack of knowledge on nuclear structure is estimated via the FSP method.« less

  9. An improved numerical method to compute neutron/gamma deexcitation cascades starting from a high spin state

    SciTech Connect

    Regnier, D.; Litaize, O.; Serot, O.

    2015-12-23

    Numerous nuclear processes involve the deexcitation of a compound nucleus through the emission of several neutrons, gamma-rays and/or conversion electrons. The characteristics of such a deexcitation are commonly derived from a total statistical framework often called “Hauser–Feshbach” method. In this work, we highlight a numerical limitation of this kind of method in the case of the deexcitation of a high spin initial state. To circumvent this issue, an improved technique called the Fluctuating Structure Properties (FSP) method is presented. Two FSP algorithms are derived and benchmarked on the calculation of the total radiative width for a thermal neutron capture on 238U. We compare the standard method with these FSP algorithms for the prediction of particle multiplicities in the deexcitation of a high spin level of 143Ba. The gamma multiplicity turns out to be very sensitive to the numerical method. The bias between the two techniques can reach 1.5 γγ/cascade. Lastly, the uncertainty of these calculations coming from the lack of knowledge on nuclear structure is estimated via the FSP method.

  10. Mobile neutron/gamma waste assay system for characterization of waste containing transuranics, uranium, and fission/activation products

    SciTech Connect

    Davidson, D.R.; Haggard, D.; Lemons, C.

    1994-12-31

    A new integrated neutron/gamma assay system has been built for measuring 55-gallon drums at Pacific Northwest Laboratory. The system is unique because it allows simultaneous measurement of neutrons and gamma-rays. This technique also allows measurement of transuranics (TRU), uranium, and fission/activation products, screening for shielded Special Nuclear Material prior to disposal, and critically determinations prior to transportation. The new system is positioned on a platform with rollers and installed inside a trailer or large van to allow transportation of the system to the waste site instead of movement of the drums to the scanner. The ability to move the system to the waste drums is particularly useful for drum retrieval programs common to all DOE sites and minimizes transportation problems on the site. For longer campaigns, the system can be moved into a facility. The mobile system consists of two separate subsystems: a passive Segmented Gamma Scanner (SGS) and a {open_quotes}clam-shell{close_quotes} passive neutron counter. The SGS with high purity germanium detector and {sup 75}Se transmission source simultaneously scan the height of the drum allowing identification of unshieled {open_quotes}hot spots{close_quotes} in the drum or segments where the matrix is too dense for the transmission source to penetrate. Dense segments can flag shielding material that could be used to hide plutonium or uranium during the gamma analysis. The passive nuetron counter with JSR-12N Neutron Coincidence Analyzer measures the coincident neutrons from the spontaneous fission of even isotopes of plutonium. Because high-density shielding produces minimal absorption of neutrons, compared to gamma rays, the passive neutron portion of the system can detect shielded SNM. Measurements to evaluate the performance of the system are still underway at Pacific Northwest Laboratory.

  11. Radiation effect on silicon transistors in mixed neutrons-gamma environment

    NASA Astrophysics Data System (ADS)

    Assaf, J.; Shweikani, R.; Ghazi, N.

    2014-10-01

    The effects of gamma and neutron irradiations on two different types of transistors, Junction Field Effect Transistor (JFET) and Bipolar Junction Transistor (BJT), were investigated. Irradiation was performed using a Syrian research reactor (RR) (Miniature Neutron Source Reactor (MNSR)) and a gamma source (Co-60 cell). For RR irradiation, MCNP code was used to calculate the absorbed dose received by the transistors. The experimental results showed an overall decrease in the gain factors of the transistors after irradiation, and the JFETs were more resistant to the effects of radiation than BJTs. The effect of RR irradiation was also greater than that of gamma source for the same dose, which could be because neutrons could cause more damage than gamma irradiation.

  12. Dose-dependent analysis of acute medical effects of mixed neutron-gamma radiation from selected severe 235U or 239Pu criticality accidents in USSR, United States, and Argentina.

    PubMed

    Barabanova, Tatyana; Wiley, Albert L; Bushmanov, Andrey

    2012-04-01

    Eight of the most severe cases of acute radiation disease (ARS) known to have occurred in humans (as the result of criticality accidents) had survival times less than 120 h (herein defined as "early death"). These accidents were analyzed and are discussed with respect to the specific accident scenarios and the resulting accident-specific, mixed neutron-gamma radiation clinical dose distributions. This analysis concludes that the cardiovascular system appears to be the most critical organ system failure for causing "early death" following approximate total body, mixed gamma-neutron radiation doses greater than 40-50 Gy. The clinical data also suggest that there was definite chest dose dependence in the resulting survival times for these eight workers, who unfortunately suffered profound radiation injury and unusual clinical effects from such high dose radiation exposures. In addition, "toxemic syndrome" is correlated with the irradiation of large volumes of soft tissues. Doses to the hands or legs greater than 80-100 Gy or radiation lung injury also play significant but secondary roles in causing "early death" in accidents delivering chest doses greater than 50 Gy.

  13. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    SciTech Connect

    Schwarze, G.E.; Frasca, A.J.

    1994-09-01

    The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10{sup 13} n/cm {sup 2} and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  14. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1991-01-01

    The effects of neutron and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10(exp 13) n/sq cm and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are presented. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  15. MA-NRBC: First successful attempt for neutron gamma discrimination in plastic scintillators

    SciTech Connect

    Normand, S.; Kondrasovs, V.; Corre, G.; Bourbotte, J. M.; Ferragut, A.

    2011-07-01

    In this paper, a new electronic hardware and algorithms enabling discrimination between neutron and gamma in plastic scintillators together with the first associated experimental results, are presented. This electronic platform is mainly based onto a quad 200 MHz ADCs. Using phase rotating, it is possible to sample the signal up to 800 MHz equivalent, with 8 bits precision. This sampling frequency allows a real time signal processing. Despite all previous work, we have shown during this study that it is possible to discriminate neutron from gamma in plastic scintillators even for low energy neutrons (less than 10 MeV). Two patents have been accepted and registered; the first deals with the intrinsic signal processing and the second with thermal stabilization methods of photomultiplier tubes. The system could be used up to 100 000 events per second (both gamma and neutron). This system is currently dedicated to homeland security devices; this is due to its response time (in the order of 1 up to 3 seconds). The next step is to implement the thermal stabilization algorithm in the FPGA and micro-controller to obtain a global system free from any trouble caused by the environment thermal variations. This aspect of the research is crucial for measurements in the field. The time response should also be improved to make it a reliable alternative to Helium-3 shortage for neutron detection at borders checkpoint. (authors)

  16. Pulsed-Neutron-Gamma (PNG) saturation monitoring at the Ketzin pilot site considering displacement and evaporation/precipitation processes

    NASA Astrophysics Data System (ADS)

    Baumann, Gunther; Henninges, Jan

    2013-04-01

    The storage of carbon dioxide (CO2) in saline aquifers is a promising option to reduce emissions of greenhouse gases to the atmosphere and to mitigate global climate change. During the proposed CO2 injection process, application of suitable techniques for monitoring of the induced changes in the subsurface is required. Existing models for the spreading of the CO2, as well as mixing of the different fluids associated with saturation changes or resulting issues from mutual solubility between brine and CO2, need to be checked. For well logging in cased boreholes, which would be the standard situation encountered under the given conditions, only a limited number of techniques like pulsed neutron-gamma (PNG) logging are applicable. The PNG technique uses controlled neutron bursts, which interact with the nuclei of the surrounding borehole and formation. Due to the collision with these neutrons, atoms from the surrounding environment emit gamma rays. The main PNG derived parameter is the capture cross section (Σ) which is derived from the decline of gamma rays with time from neutron capture processes. The high Σ contrast between brine and CO2 results in a high sensitivity to evaluate saturation changes. This makes PNG monitoring favourable for saturation profiling especially in time-lapse mode. Previously, the conventional PNG saturation model based on a displacement process has been used for PNG interpretation in different CO2 storage projects in saline aquifers. But in addition to the displacement process, the mutual solubility between brine and CO2 adds further complex processes like evaporation and salt precipitation, which are not considered in PNG saturation models. These evaporation and precipitation processes are relevant in the vicinity of an injection well, where dry CO2 enters the reservoir. The Σ brine value depends strongly on the brine salinity e.g. its chlorine content which makes PNG measurements suitable for evaporation and salt precipitation

  17. Quinolone and Glycopeptide Therapy for Infection in Mouse Following Exposure to Mixed-Field Neutron-Gamma-Photon Radiation

    DTIC Science & Technology

    1993-01-01

    J. E., 1977, Varcomycin. AMaovo Clinic Proceedings, 52, isms in the gastrointestinal tract and increased the 631-634. risk of candidemia (Ricket el...BROOK, I., ELLIOTT, T. B. and LEDNEY, G. D., 1990, Quinolone JARVIS, W. R., 1991, Risk factors for candidemia in therapy of Klebsiella pneumoniae

  18. An overview of field specific designs of microbial EOR

    SciTech Connect

    Robertson, E.P.; Bala, G.A.; Fox, S.L.; Jackson, J.D.; Thomas, C.P.

    1995-12-01

    The selection and design of a microbial enhanced oil recovery (MEOR) process for application in a specific field involves geological, reservoir, and biological characterization. Microbially mediated oil recovery mechanisms (biogenic gas, biopolymers, and biosurfactants) are defined by the types of microorganisms used. The engineering and biological character of a given reservoir must be understood to correctly select a microbial system to enhance oil recovery. The objective of this paper is to discuss the methods used to evaluate three fields with distinct characteristics and production problems for the applicability of MEOR technology. Reservoir characteristics and laboratory results indicated that MEOR would not be applicable in two of the three fields considered. The development of a microbial oil recovery process for the third field appeared promising. Development of a bacterial consortium capable of producing the desired metabolites was initiated and field isolates were characterized.

  19. An overview of field-specific designs of microbial EOR

    SciTech Connect

    Robertson, E.P.; Bala, G.A.; Fox, S.L.; Jackson, J.D.; Thomas, C.P.

    1995-12-31

    The selection and design of an MEOR process for application in a specific field involves geological, reservoir, and biological characterization. Microbially mediated oil recovery mechanisms (bigenic gas, biopolymers, and biosurfactants) are defined by the types of microorganisms used. The engineering and biological character of a given reservoir must be understood to correctly select a microbial system to enhance oil recovery. This paper discusses the methods used to evaluate three fields with distinct characteristics and production problems for the applicability of MEOR would not be applicable in two of the three fields considered. The development of a microbial oil recovery process for the third field appeared promising. Development of a bacterial consortium capable of producing the desired metabolites was initiated, and field isolates were characterized.

  20. Infrared image detail enhancement based on the gradient field specification.

    PubMed

    Zhao, Wenda; Xu, Zhijun; Zhao, Jian; Zhao, Fan; Han, Xizhen

    2014-07-01

    Human vision is sensitive to the changes of local image details, which are actually image gradients. To enhance faint infrared image details, this article proposes a gradient field specification algorithm. First we define the image gradient field and gradient histogram. Then, by analyzing the characteristics of the gradient histogram, we construct a Gaussian function to obtain the gradient histogram specification and therefore obtain the transform gradient field. In addition, subhistogram equalization is proposed based on the histogram equalization to improve the contrast of infrared images. The experimental results show that the algorithm can effectively improve image contrast and enhance weak infrared image details and edges. As a result, it can give qualified image information for different applications of an infrared image. In addition, it can also be applied to enhance other types of images such as visible, medical, and lunar surface.

  1. Behavior Degradation Due to 1100-RAD Pulsed Radiation Exposure (5.8:1 Neutron/Gamma Ratio).

    DTIC Science & Technology

    1984-10-01

    34 A v ;- . t Codes" Dtis S -. 1 19i : ° : -Co on c lu . . . . . . . . . . . . . . . . . . . . . . . ... . ..... ... 34 ",’- -. 1 21..Absorptive...radiobiology and radiotherapy with fast neutrons. Curr Top Radiat Res Q 11:1-86 (1976). 10. Field, S. B. Early and late normal tissue damage after fast neutrons

  2. Development of a specific anaerobic field test for aerobic gymnastics.

    PubMed

    Alves, Christiano Robles Rodrigues; Borelli, Marcello Tadeu Caetano; Paineli, Vitor de Salles; Azevedo, Rafael de Almeida; Borelli, Claudia Cristine Gomes; Lancha Junior, Antônio Herbert; Gualano, Bruno; Artioli, Guilherme Giannini

    2015-01-01

    The current investigation aimed to develop a valid specific field test to evaluate anaerobic physical performance in Aerobic Gymnastics athletes. We first designed the Specific Aerobic Gymnast Anaerobic Test (SAGAT), which included gymnastics-specific elements performed in maximal repeated sprint fashion, with a total duration of 80-90 s. In order to validate the SAGAT, three independent sub-studies were performed to evaluate the concurrent validity (Study I, n=8), the reliability (Study II, n=10) and the sensitivity (Study III, n=30) of the test in elite female athletes. In Study I, a positive correlation was shown between lower-body Wingate test and SAGAT performance (Mean power: p = 0.03, r = -0.69, CI: -0.94 to 0.03 and Peak power: p = 0.02, r = -0.72, CI: -0.95 to -0.04) and between upper-body Wingate test and SAGAT performance (Mean power: p = 0.03, r = -0.67, CI: -0.94 to 0.02 and Peak power: p = 0.03, r = -0.69, CI: -0.94 to 0.03). Additionally, plasma lactate was similarly increased in response to SAGAT (p = 0.002), lower-body Wingate Test (p = 0.021) and a simulated competition (p = 0.007). In Study II, no differences were found between the time to complete the SAGAT in repeated trials (p = 0.84; Cohen's d effect size = 0.09; ICC = 0.97, CI: 0.89 to 0.99; MDC95 = 0.12 s). Finally, in Study III the time to complete the SAGAT was significantly lower during the competition cycle when compared to the period before the preparatory cycle (p < 0.001), showing an improvement in SAGAT performance after a specific Aerobic Gymnastics training period. Taken together, these data have demonstrated that SAGAT is a specific, reliable and sensitive measurement of specific anaerobic performance in elite female Aerobic Gymnastics, presenting great potential to be largely applied in training settings.

  3. Development of a Specific Anaerobic Field Test for Aerobic Gymnastics

    PubMed Central

    Paineli, Vitor de Salles; Azevedo, Rafael de Almeida; Borelli, Claudia Cristine Gomes; Lancha Junior, Antônio Herbert; Gualano, Bruno; Artioli, Guilherme Giannini

    2015-01-01

    The current investigation aimed to develop a valid specific field test to evaluate anaerobic physical performance in Aerobic Gymnastics athletes. We first designed the Specific Aerobic Gymnast Anaerobic Test (SAGAT), which included gymnastics-specific elements performed in maximal repeated sprint fashion, with a total duration of 80-90 s. In order to validate the SAGAT, three independent sub-studies were performed to evaluate the concurrent validity (Study I, n=8), the reliability (Study II, n=10) and the sensitivity (Study III, n=30) of the test in elite female athletes. In Study I, a positive correlation was shown between lower-body Wingate test and SAGAT performance (Mean power: p = 0.03, r = -0.69, CI: -0.94 to 0.03 and Peak power: p = 0.02, r = -0.72, CI: -0.95 to -0.04) and between upper-body Wingate test and SAGAT performance (Mean power: p = 0.03, r = -0.67, CI: -0.94 to 0.02 and Peak power: p = 0.03, r = -0.69, CI: -0.94 to 0.03). Additionally, plasma lactate was similarly increased in response to SAGAT (p = 0.002), lower-body Wingate Test (p = 0.021) and a simulated competition (p = 0.007). In Study II, no differences were found between the time to complete the SAGAT in repeated trials (p = 0.84; Cohen’s d effect size = 0.09; ICC = 0.97, CI: 0.89 to 0.99; MDC95 = 0.12 s). Finally, in Study III the time to complete the SAGAT was significantly lower during the competition cycle when compared to the period before the preparatory cycle (p < 0.001), showing an improvement in SAGAT performance after a specific Aerobic Gymnastics training period. Taken together, these data have demonstrated that SAGAT is a specific, reliable and sensitive measurement of specific anaerobic performance in elite female Aerobic Gymnastics, presenting great potential to be largely applied in training settings. PMID:25876039

  4. Tissue-specific transcriptomics in the field cricket Teleogryllus oceanicus.

    PubMed

    Bailey, Nathan W; Veltsos, Paris; Tan, Yew-Foon; Millar, A Harvey; Ritchie, Michael G; Simmons, Leigh W

    2013-02-01

    Field crickets (family Gryllidae) frequently are used in studies of behavioral genetics, sexual selection, and sexual conflict, but there have been no studies of transcriptomic differences among different tissue types. We evaluated transcriptome variation among testis, accessory gland, and the remaining whole-body preparations from males of the field cricket, Teleogryllus oceanicus. Non-normalized cDNA libraries from each tissue were sequenced on the Roche 454 platform, and a master assembly was constructed using testis, accessory gland, and whole-body preparations. A total of 940,200 reads were assembled into 41,962 contigs, to which 36,856 singletons (reads not assembled into a contig) were added to provide a total of 78,818 sequences used in annotation analysis. A total of 59,072 sequences (75%) were unique to one of the three tissues. Testis tissue had the greatest proportion of tissue-specific sequences (62.6%), followed by general body (56.43%) and accessory gland tissue (44.16%). We tested the hypothesis that tissues expressing gene products expected to evolve rapidly as a result of sexual selection--testis and accessory gland--would yield a smaller proportion of BLASTx matches to homologous genes in the model organism Drosophila melanogaster compared with whole-body tissue. Uniquely expressed sequences in both testis and accessory gland showed a significantly lower rate of matching to annotated D. melanogaster genes compared with those from general body tissue. These results correspond with empirical evidence that genes expressed in testis and accessory gland tissue are rapidly evolving targets of selection.

  5. Tissue-Specific Transcriptomics in the Field Cricket Teleogryllus oceanicus

    PubMed Central

    Bailey, Nathan W.; Veltsos, Paris; Tan, Yew-Foon; Millar, A. Harvey; Ritchie, Michael G.; Simmons, Leigh W.

    2013-01-01

    Field crickets (family Gryllidae) frequently are used in studies of behavioral genetics, sexual selection, and sexual conflict, but there have been no studies of transcriptomic differences among different tissue types. We evaluated transcriptome variation among testis, accessory gland, and the remaining whole-body preparations from males of the field cricket, Teleogryllus oceanicus. Non-normalized cDNA libraries from each tissue were sequenced on the Roche 454 platform, and a master assembly was constructed using testis, accessory gland, and whole-body preparations. A total of 940,200 reads were assembled into 41,962 contigs, to which 36,856 singletons (reads not assembled into a contig) were added to provide a total of 78,818 sequences used in annotation analysis. A total of 59,072 sequences (75%) were unique to one of the three tissues. Testis tissue had the greatest proportion of tissue-specific sequences (62.6%), followed by general body (56.43%) and accessory gland tissue (44.16%). We tested the hypothesis that tissues expressing gene products expected to evolve rapidly as a result of sexual selection—testis and accessory gland—would yield a smaller proportion of BLASTx matches to homologous genes in the model organism Drosophila melanogaster compared with whole-body tissue. Uniquely expressed sequences in both testis and accessory gland showed a significantly lower rate of matching to annotated D. melanogaster genes compared with those from general body tissue. These results correspond with empirical evidence that genes expressed in testis and accessory gland tissue are rapidly evolving targets of selection. PMID:23390599

  6. Reliability and validity of the soccer specific INTER field test.

    PubMed

    Aandstad, Anders; Simon, Elena V

    2013-01-01

    The aims of this study were to explain how the Intermittent Endurance Running (INTER) test is executed, describe physiological responses during testing, and evaluate reliability and content validity in this new soccer specific test. The test consists of 20 m shuttle running, interspersed with straight sprints, agility sprints, walking and resting. Shuttle run speed is increased at each level until exhaustion. Thirteen male professional players participated in the present study. Exercise tolerance time, distance covered, mean blood lactate and mean heart rate were 25:51 ± 2:41 min, 2892 ± 324 m, 5.5 ± 1.2 mmol · L(-1) and 161 ± 11 beats · min(-1), respectively, during the INTER test. Sprint and agility performance decreased significantly at higher levels. Eight of the players performed a retest for reliability evaluations. Mean difference ± 95% limits of agreement, coefficient of variation (CV) and intraclass correlation coefficient (ICC) for exercise tolerance time between test and retest were -00:41 ± 02:25 min, 2.5% and 0.75, respectively. The CV for sprint and agility performance between test and retest was <1%. The INTER test mimics soccer games on distance/time ratio, frequency of sprints, heart rate and blood lactate values, and could be an alternative field test for evaluating essential physical performance aspects in soccer players.

  7. Proton Neutron Gamma-X Detection (PNGXD): An introduction to contrast agent detection during proton therapy via prompt gamma neutron activation

    NASA Astrophysics Data System (ADS)

    Gräfe, James L.

    2017-09-01

    experimental work are required to determine the feasibility of this new technique termed Proton Neutron Gamma-X Detection (PNGXD). The initial concept of this procedure is presented in this paper as well as future research directions.

  8. Educationally Applied Psycholinguistics: Toward a Specification of the Field.

    ERIC Educational Resources Information Center

    Prucha, Jan

    1988-01-01

    Offers a general review of applications of psycholinguistic theory, focusing on applications in the field of education. Studies already undertaken and future areas for study are discussed, and guidelines for conducting psycholinguistic research in the classroom are proposed. (CFM)

  9. Scalable graphene field-effect sensors for specific protein detection.

    PubMed

    Saltzgaber, Grant; Wojcik, Peter; Sharf, Tal; Leyden, Matthew R; Wardini, Jenna L; Heist, Christopher A; Adenuga, Adeniyi A; Remcho, Vincent T; Minot, Ethan D

    2013-09-06

    We demonstrate that micron-scale graphene field-effect transistor biosensors can be fabricated in a scalable fashion from large-area chemical vapor deposition derived graphene. We electrically detect the real-time binding and unbinding of a protein biomarker, thrombin, to and from aptamer-coated graphene surfaces. Our sensors have low background noise and high transconductance, comparable to exfoliated graphene devices. The devices are reusable and have a shelf-life greater than one week.

  10. 40 CFR 86.1375-2007 - Equipment specifications for field testing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Equipment specifications for field... Exhaust Test Procedures § 86.1375-2007 Equipment specifications for field testing. For testing conducted with engines installed in vehicles, including field testing conducted to measure emissions under...

  11. 40 CFR 86.1375-2007 - Equipment specifications for field testing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Equipment specifications for field... Exhaust Test Procedures § 86.1375-2007 Equipment specifications for field testing. For testing conducted with engines installed in vehicles, including field testing conducted to measure emissions under...

  12. 40 CFR 86.1375-2007 - Equipment specifications for field testing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Equipment specifications for field... Exhaust Test Procedures § 86.1375-2007 Equipment specifications for field testing. For testing conducted with engines installed in vehicles, including field testing conducted to measure emissions under...

  13. 40 CFR 86.1375-2007 - Equipment specifications for field testing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Equipment specifications for field... Exhaust Test Procedures § 86.1375-2007 Equipment specifications for field testing. For testing conducted with engines installed in vehicles, including field testing conducted to measure emissions under...

  14. Specific and non-specific immunity of piglets from sows fed diets containing specific fatty acids in field conditions.

    PubMed

    Benzoni, G; Foresti, F; Archetti, I L; Coceva, G; Guyonvarch, A; Alborali, L

    2013-10-01

    The transfer of passive immunity from sows to piglets is important and it is the first immune protection of the new born piglet. Improving sows immunity by adding immuno-stimulating product in sows diet can positively affect colostrum composition and transfer of immune molecules to piglets. The aim of the current study is to evaluate the benefit of a different solution, made of specific fatty acids from marine origin that have been used in human medicine for decades, for sows and piglets. Two trials were conducted in commercial farm, involving 240 sows at different periods of the year. Sows were divided in a control group, without supplementation, and a test group, supplemented with the feed additive from the 90th day of gestation to weaning. Sows body condition, piglets viability and growth were recorded. Milk immunoglobulin content was measured, as well as Aujeszky antibodies in sows and piglets blood as marker of specific immunity, and blood bactericidal activity, complement activity and lysozyme as markers of non specific immunity. No effect of the product was observed on piglets zootechnical criteria and specific immunity parameters but significant improvement of piglet non specific immunity, was observed. No difference was observed neither in the piglets blood PRRSV and PCV2 antibodies and viruses nor in Aujeszky antibodies. Blood complement activity seems to be an accurate indicator of immuno-stimulating additive efficiency. Giving alkyl-glycerol fatty acids to sows in late gestation and lactation can improve the passive immunity transfer to piglets.

  15. Neutron Reference Benchmark Field Specification: ACRR Free-Field Environment (ACRR-FF-CC-32-CL).

    SciTech Connect

    Vega, Richard Manuel; Parma, Edward J.; Griffin, Patrick J.; Vehar, David W.

    2015-07-01

    This report was put together to support the International Atomic Energy Agency (IAEA) REAL- 2016 activity to validate the dosimetry community’s ability to use a consistent set of activation data and to derive consistent spectral characterizations. The report captures details of integral measurements taken in the Annular Core Research Reactor (ACRR) central cavity free-field reference neutron benchmark field. The field is described and an “a priori” calculated neutron spectrum is reported, based on MCNP6 calculations, and a subject matter expert (SME) based covariance matrix is given for this “a priori” spectrum. The results of 31 integral dosimetry measurements in the neutron field are reported.

  16. Method for measuring specific heats in intense magnetic fields at low temperatures using capacitance thermometry

    NASA Astrophysics Data System (ADS)

    Lawless, W. N.; Clark, C. F.; Arenz, R. W.

    1982-11-01

    A drift method is described for measuring specific heats in intense magnetic fields at low temperatures. Capacitance thermometry is used, and an automated data-collection system utilizes the imbalance of a transformer-ratio-arm bridge to process the capacitance data. The zero-field specific heat must be known, and measurement of the in situ drift in zero-field calibrates the thermal link. Additional calibration of the link is required if the link's magnetothermal conductivity effects are significant, and a specific example of a copper-wire link is presented. The method resolves complex structure in the specific heat near a steep λ-type anomaly, as illustrated by measurements on a chromite spinel at 7.5 T. The uncertainty in the method is estimated to be ≂±7%.

  17. Assessing Field-Specific Risk of Soybean Sudden Death Syndrome Using Satellite Imagery in Iowa.

    PubMed

    Yang, S; Li, X; Chen, C; Kyveryga, P; Yang, X B

    2016-08-01

    Moderate resolution imaging spectroradiometer (MODIS) satellite imagery from 2004 to 2013 were used to assess the field-specific risks of soybean sudden death syndrome (SDS) caused by Fusarium virguliforme in Iowa. Fields with a high frequency of significant decrease (>10%) of the normalized difference vegetation index (NDVI) observed in late July to middle August on historical imagery were hypothetically considered as high SDS risk. These high-risk fields had higher slopes and shorter distances to flowlines, e.g., creeks and drainages, particularly in the Des Moines lobe. Field data in 2014 showed a significantly higher SDS level in the high-risk fields than fields selected without considering NDVI information. On average, low-risk fields had 10 times lower F. virguliforme soil density, determined by quantitative polymerase chain reaction, compared with other surveyed fields. Ordinal logistic regression identified positive correlations between SDS and slope, June NDVI, and May maximum temperature, but high June maximum temperature hindered SDS. A modeled SDS risk map showed a clear trend of potential disease occurrences across Iowa. Landsat imagery was analyzed similarly, to discuss the ability to utilize higher spatial resolution data. The results demonstrated the great potential of both MODIS and Landsat imagery for SDS field-specific risk assessment.

  18. Specific heat in KFe2As2 in zero and applied magnetic field

    NASA Astrophysics Data System (ADS)

    Kim, J. S.; Kim, E. G.; Stewart, G. R.; Chen, X. H.; Wang, X. F.

    2011-05-01

    The specific heat down to 0.08 K of the iron pnictide superconductor KFe2As2 was measured on a single-crystal sample with a residual resistivity ratio of ˜650, with a Tconset determined by a specific heat of 3.7 K. The zero-field normal-state specific heat divided by temperature, C/T, was extrapolated from above Tc to T=0 by insisting on agreement between the extrapolated normal-state entropy at Tc, Snextrap(Tc), and the measured superconducting-state entropy at Tc, Ssmeas(Tc), since for a second-order phase transition the two entropies must be equal. This extrapolation would indicate that this rather clean sample of KFe2As2 exhibits non-Fermi-liquid behavior; i.e., C/T increases at low temperatures, in agreement with the reported non-Fermi-liquid behavior in the resistivity. However, specific heat as a function of magnetic field shows that the shoulder feature around 0.7 K, which is commonly seen in KFe2As2 samples, is not evidence for a second superconducting gap as has been previously proposed but instead is due to an unknown magnetic impurity phase, which can affect the entropy balance and the extrapolation of the normal-state specific heat. This peak (somewhat larger in magnitude) with similar field dependence is also found in a less pure sample of KFe2As2, with a residual resistivity ratio of only 90 and Tconset=3.1 K. These data, combined with the measured normal-state specific heat in field to suppress superconductivity, allow the conclusion that an increase in the normal-state specific heat as T→0 is in fact not seen in KFe2As2; i.e., Fermi-liquid behavior is observed.

  19. Field Dependence-Independence as Predictor of Specific Reading Skills in Two First Grade Reading Programs.

    ERIC Educational Resources Information Center

    Dermott, R. Allan; And Others

    1979-01-01

    Details an investigation of the relative contribution of two dimensions of field dependence-independence to the prediction of specific reading skills for first-grade children in an intensive phonics program and in a basal reader program supplemented with phonics. (FL)

  20. Teaching Suprasegmentals to International Teaching Assistants Using Field-Specific Materials.

    ERIC Educational Resources Information Center

    Anderson-Hsieh, Janet

    1990-01-01

    Reviews literature dealing with International Teaching Assistants and provides a rationale for teaching them pronunciation using cognitive-based field-specific methods. An account of the application of such a teaching method to instruct Chinese and Korean chemistry teaching assistants at a North American University is also given. (55 references)…

  1. Field Operations and Enforcement Manual for Air Pollution Control. Volume III: Inspection Procedures for Specific Industries.

    ERIC Educational Resources Information Center

    Weisburd, Melvin I.

    The Field Operations and Enforcement Manual for Air Pollution Control, Volume III, explains in detail the following: inspection procedures for specific sources, kraft pulp mills, animal rendering, steel mill furnaces, coking operations, petroleum refineries, chemical plants, non-ferrous smelting and refining, foundries, cement plants, aluminum…

  2. Field Operations and Enforcement Manual for Air Pollution Control. Volume III: Inspection Procedures for Specific Industries.

    ERIC Educational Resources Information Center

    Weisburd, Melvin I.

    The Field Operations and Enforcement Manual for Air Pollution Control, Volume III, explains in detail the following: inspection procedures for specific sources, kraft pulp mills, animal rendering, steel mill furnaces, coking operations, petroleum refineries, chemical plants, non-ferrous smelting and refining, foundries, cement plants, aluminum…

  3. Specific absorption rate and electric field measurements in the near field of six mobile phone base station antennas.

    PubMed

    Toivonen, Tommi; Toivo, Tim; Puranen, Lauri; Jokela, Kari

    2009-05-01

    In this article, the exposure to radio frequency electromagnetic fields was studied in close proximity (distances of 10, 100, 300, and 600 mm) to six base station antennas. The specific absorption rate (SAR) in 800 mm x 500 mm x 200 mm box phantom as well as unperturbed electric field (E) in air was measured. The results were used to determine whether the measurement of local maximum of unperturbed electric field can be used as a compliance check for local exposure. Also, the conservativeness of this assessment method compared to the ICNIRP basic restriction was studied. Moreover, the assessment of whole-body exposure was discussed and the distance ranges presented in which the ICNIRP limit for local exposure could be exceeded before the limit for whole-body SAR. These results show that the electric field measurement alone can be used for easy compliance check for the local exposure at all distances and for all antenna types studied. However, in some cases when the local peak value of E was compared directly to the ICNIRP reference level for unperturbed E, the exposure was overestimated only very slightly (by factor 1.1) compared to the basic restriction for localized SAR in a human, and hence these results can not be generalized to all antenna types. Moreover, it was shown that the limit for localized exposure could be exceeded before the limit for the whole-body average SAR, if the distance to the antenna was less than 240 mm.

  4. Field experimental approach to bromide leaching as affected by scale-specific rainfall characteristics

    NASA Astrophysics Data System (ADS)

    Wendroth, Ole; Vasquez, Vicente; Matocha, Christopher J.

    2011-06-01

    Although inherent soil spatial and temporal variabilities complicate analysis of solute leaching, impacts of specific processes associated with rainfall amount, intensity, and frequency on solute leaching under field conditions require investigation. The objective of this study was to introduce (1) a new experimental approach to quantify bromide (Br-) leaching under field conditions as influenced by rainfall characteristics and (2) analytical opportunities applicable to scale-specific spatial treatment distribution. The quantitative range of treatments was established in nonrandom periodically oscillating patterns. The characteristic length of a period over which a treatment fluctuates was considered the specific treatment scale. A Br- tracer study was established in the field with treatments applied at two different spatial scales. The tracer was applied with a sprayer in a transect of 32 plots, each 2 m long, followed by a site-specific sprinkler irrigation, and 128 soil cores subsequently taken at 0.5 m intervals and divided into 10-cm depth increments. The scale-specific associations between treatments and Br- center of mass (COM) were addressed. Treatments can be periodically imposed over specific scales and their spatial relationships quantified with semivariance and power spectral analysis. An additive state-space model was applied to separate the long- and short-wave components of Br- COM. Subsequently, the large-scale process was described in an autoregressive state-space model. The proposed experimental approach and the separation of small- and large-scale variability components support studying soil ecosystem processes that vary at different scales even in the presence of underlying large-scale trends that are currently considered obstacles in field research.

  5. Development of pressure cell for specific heat measurement at low temperature and high Magnetic field

    NASA Astrophysics Data System (ADS)

    Kawae, T.; Yaita, K.; Yoshida, Y.; Inagaki, Y.; Ohashi, M.; Oomi, G.; Matsubayashi, K.; Matsumoto, T.; Uwatoko, Y.

    2009-02-01

    We report the performance of Ag-Pd-Cu alloy as the material of a pressure cell to carry out specific heat measurements at low temperatures and high magnetic fields. The Ag-Pd-Cu alloy is advantageous to reduce the background due to the nuclear specific heat in the pressure cell growing at low temperatures and high magnetic fields. We prepared 70-20-10 alloy composed of 70 mass % of Ag, 20 mass % of Pd, and 10 mass % of Cu. The maximum hardness over 100 HRB (Rockwell-B scale) is achieved by the heat treatment. The magnetization and susceptibility results show that the alloy includes a small amount of magnetic ions, whose concentration is smaller than that in the Be-Cu alloy. We confirm that the specific heat of a piston cylinder cell made of the 70-20-10 alloy increases smoothly from 0.2 to 9 K and the nuclear specific heat decreases drastically in magnetic field compared to that expected in the Be-Cu alloy. The pressure value in the cell at low temperature increases almost linearly up to P =0.4 GPa, which is nearly the limit of the inner piston made of the 70-20-10 alloy, with increasing of the load applied at room temperature.

  6. The role of specific humidity fields in the diagnosis of stratosphere troposphere exchange

    SciTech Connect

    Gray, L.J.; Bithell, M.; Cox, B.D.

    1994-09-01

    METEOSAT 4 satellite observations of water vapor show evidence of a rich spectrum of fine scale structure that may be indicative of the transfer of dry, ozone-rich air from the stratosphere deep into the troposphere (Appenzeller and Davies, 1992). The extent to which air within stratospheric intrusions is irreversibly mixed and remains in the troposphere is of considerable current interest, particularly in respect of pollution effects of increasing numbers of subsonic and supersonic aircraft flights that traverse the lower stratosphere. We diagnose potential vorticity and the corresponding distributions of specific humidity from a numerical weather forecast model and show that the latter field displays many of the characteristics of the Meteosat data. Specific humidity fields on both a pressure surface which corresponds approximately to the Meteosat data sampling and on an isentropic surface are compared. We show the presence of streamer-like features in specific humidity that are not evident in the PV fields. We also note the prediliction for the streamers to break off, be advected by the flow and to subsequently become `attached` to other features. Care is therefore required in the interpretation of the Meteosat data for stratosphere troposphere exchange studies. Nevertheless, we suggest that the importance of specific humidity as an indicator of the dynamical evolution of upper level atmospheric flow has previously been overlooked.

  7. Magnetic Field Dependence of the Specific Heat of CuGeO_3

    NASA Astrophysics Data System (ADS)

    Brill, J. W.; Kuo, Y.-K.; Powell, D. K.

    1996-03-01

    In previous work,(Y.K. Kuo, et al. al), Solid State Commun. \\underline94, 385 (1995). we showed that the specific heat anomaly of CuGeO3 at its T_c=14 K spin-Peierls transition was surprisingly close to mean-field in magnitude, but that at lower temperatures the excess specific heat (Δc ≡ cP - βT^3) greatly exceeded its mean-field value. We have now measured the magnetic field (B<7T) dependence of cP in the low field, diamagnetic, dimerized state using ac (f ≈ 30 Hz) calorimetry.^1 We find that Δc(T/T_c(B),B) ≈ Δc(T/T_c(0),0) this field dependence is at least 3 times weaker than expected from the Zeeman splitting of the triplet magnon excitations,(O. Fujita, et al. al), Phys. Rev. Lett. \\underline74, 1677 (1995). suggesting that changes in thermal occupation of Sz = ±1 magnons (at τ ≈ 5 ms) is suppressed. *Supported in part by NSF Grants EHR-9108764 and DMR-9300507.

  8. A field size specific backscatter correction algorithm for accurate EPID dosimetry.

    PubMed

    Berry, Sean L; Polvorosa, Cynthia S; Wuu, Cheng-Shie

    2010-06-01

    Portal dose images acquired with an amorphous silicon electronic portal imaging device (EPID) suffer from artifacts related to backscattered radiation. The backscatter signal varies as a function of field size (FS) and location on the EPID. Most current portal dosimetry algorithms fail to account for the FS dependence. The ramifications of this omission are investigated and solutions for correcting the measured dose images for FS specific backscatter are proposed. A series of open field dose images were obtained for field sizes ranging from 2×2 to 30×40cm2. Each image was analyzed to determine the amount of backscatter present. Two methods to account for the relationship between FS and backscatter are offered. These include the use of discrete FS specific correction matrices and the use of a single generalized equation. The efficacy of each approach was tested on the clinical dosimetric images for ten patients, 49 treatment fields. The fields were evaluated to determine whether there was an improvement in the dosimetric result over the commercial vendor's current algorithm. It was found that backscatter manifests itself as an asymmetry in the measured signal primarily in the inplane direction. The maximum error is approximately 3.6% for 10×10 and 12.5×12.5cm2 field sizes. The asymmetry decreased with increasing FS to approximately 0.6% for fields larger than 30×30cm2. The dosimetric comparison between the measured and predicted dose images was significantly improved (p⪡.001) when a FS specific backscatter correction was applied. The average percentage of points passing a 2%, 2 mm gamma criteria increased from 90.6% to between 96.7% and 97.2% after the proposed methods were employed. The error observed in a measured portal dose image depends on how much its FS differs from the 30×40cm2 calibration conditions. The proposed methods for correcting for FS specific backscatter effectively improved the ability of the EPID to perform dosimetric measurements

  9. Targeted treatment of cancer with radiofrequency electromagnetic fields amplitude-modulated at tumor-specific frequencies

    PubMed Central

    Zimmerman, Jacquelyn W.; Jimenez, Hugo; Pennison, Michael J.; Brezovich, Ivan; Morgan, Desiree; Mudry, Albert; Costa, Frederico P.; Barbault, Alexandre; Pasche, Boris

    2013-01-01

    In the past century, there have been many attempts to treat cancer with low levels of electric and magnetic fields. We have developed noninvasive biofeedback examination devices and techniques and discovered that patients with the same tumor type exhibit biofeedback responses to the same, precise frequencies. Intrabuccal administration of 27.12 MHz radiofrequency (RF) electromagnetic fields (EMF), which are amplitude-modulated at tumor-specific frequencies, results in long-term objective responses in patients with cancer and is not associated with any significant adverse effects. Intrabuccal administration allows for therapeutic delivery of very low and safe levels of EMF throughout the body as exemplified by responses observed in the femur, liver, adrenal glands, and lungs. In vitro studies have demonstrated that tumor-specific frequencies identified in patients with various forms of cancer are capable of blocking the growth of tumor cells in a tissue- and tumor-specific fashion. Current experimental evidence suggests that tumor-specific modulation frequencies regulate the expression of genes involved in migration and invasion and disrupt the mitotic spindle. This novel targeted treatment approach is emerging as an appealing therapeutic option for patients with advanced cancer given its excellent tolerability. Dissection of the molecular mechanisms accounting for the anti-cancer effects of tumor-specific modulation frequencies is likely to lead to the discovery of novel pathways in cancer. PMID:24206915

  10. Targeted treatment of cancer with radiofrequency electromagnetic fields amplitude-modulated at tumor-specific frequencies.

    PubMed

    Zimmerman, Jacquelyn W; Jimenez, Hugo; Pennison, Michael J; Brezovich, Ivan; Morgan, Desiree; Mudry, Albert; Costa, Frederico P; Barbault, Alexandre; Pasche, Boris

    2013-11-01

    In the past century, there have been many attempts to treat cancer with low levels of electric and magnetic fields. We have developed noninvasive biofeedback examination devices and techniques and discovered that patients with the same tumor type exhibit biofeedback responses to the same, precise frequencies. Intrabuccal administration of 27.12 MHz radiofrequency (RF) electromagnetic fields (EMF), which are amplitude-modulated at tumor-specific frequencies, results in long-term objective responses in patients with cancer and is not associated with any significant adverse effects. Intrabuccal administration allows for therapeutic delivery of very low and safe levels of EMF throughout the body as exemplified by responses observed in the femur, liver, adrenal glands, and lungs. In vitro studies have demonstrated that tumor-specific frequencies identified in patients with various forms of cancer are capable of blocking the growth of tumor cells in a tissue- and tumor-specific fashion. Current experimental evidence suggests that tumor-specific modulation frequencies regulate the expression of genes involved in migration and invasion and disrupt the mitotic spindle. This novel targeted treatment approach is emerging as an appealing therapeutic option for patients with advanced cancer given its excellent tolerability. Dissection of the molecular mechanisms accounting for the anti-cancer effects of tumor-specific modulation frequencies is likely to lead to the discovery of novel pathways in cancer.

  11. Specific-heat exponent and modified hyperscaling in the 4D random-field Ising model

    NASA Astrophysics Data System (ADS)

    Fytas, N. G.; Martín-Mayor, V.; Picco, M.; Sourlas, N.

    2017-03-01

    We report a high-precision numerical estimation of the critical exponent α of the specific heat of the random-field Ising model in four dimensions. Our result α =0.12(1) indicates a diverging specific-heat behavior and is consistent with the estimation coming from the modified hyperscaling relation using our estimate of θ via the anomalous dimensions η and \\barη . Our analysis benefited from a high-statistics zero-temperature numerical simulation of the model for two distributions of the random fields, namely a Gaussian and Poissonian distribution, as well as recent advances in finite-size scaling and reweighting methods for disordered systems. An original estimate of the critical slowing down exponent z of the maximum-flow algorithm used is also provided.

  12. Reference field specification and preliminary beam selection strategy for accelerator-based GCR simulation.

    PubMed

    Slaba, Tony C; Blattnig, Steve R; Norbury, John W; Rusek, Adam; La Tessa, Chiara

    2016-02-01

    The galactic cosmic ray (GCR) simulator at the NASA Space Radiation Laboratory (NSRL) is intended to deliver the broad spectrum of particles and energies encountered in deep space to biological targets in a controlled laboratory setting. In this work, certain aspects of simulating the GCR environment in the laboratory are discussed. Reference field specification and beam selection strategies at NSRL are the main focus, but the analysis presented herein may be modified for other facilities and possible biological considerations. First, comparisons are made between direct simulation of the external, free space GCR field and simulation of the induced tissue field behind shielding. It is found that upper energy constraints at NSRL limit the ability to simulate the external, free space field directly (i.e. shielding placed in the beam line in front of a biological target and exposed to a free space spectrum). Second, variation in the induced tissue field associated with shielding configuration and solar activity is addressed. It is found that the observed variation is likely within the uncertainty associated with representing any GCR reference field with discrete ion beams in the laboratory, given current facility constraints. A single reference field for deep space missions is subsequently identified. Third, a preliminary approach for selecting beams at NSRL to simulate the designated reference field is presented. This approach is not a final design for the GCR simulator, but rather a single step within a broader design strategy. It is shown that the beam selection methodology is tied directly to the reference environment, allows facility constraints to be incorporated, and may be adjusted to account for additional constraints imposed by biological or animal care considerations. The major biology questions are not addressed herein but are discussed in a companion paper published in the present issue of this journal. Drawbacks of the proposed methodology are discussed

  13. Reference field specification and preliminary beam selection strategy for accelerator-based GCR simulation

    NASA Astrophysics Data System (ADS)

    Slaba, Tony C.; Blattnig, Steve R.; Norbury, John W.; Rusek, Adam; La Tessa, Chiara

    2016-02-01

    The galactic cosmic ray (GCR) simulator at the NASA Space Radiation Laboratory (NSRL) is intended to deliver the broad spectrum of particles and energies encountered in deep space to biological targets in a controlled laboratory setting. In this work, certain aspects of simulating the GCR environment in the laboratory are discussed. Reference field specification and beam selection strategies at NSRL are the main focus, but the analysis presented herein may be modified for other facilities and possible biological considerations. First, comparisons are made between direct simulation of the external, free space GCR field and simulation of the induced tissue field behind shielding. It is found that upper energy constraints at NSRL limit the ability to simulate the external, free space field directly (i.e. shielding placed in the beam line in front of a biological target and exposed to a free space spectrum). Second, variation in the induced tissue field associated with shielding configuration and solar activity is addressed. It is found that the observed variation is likely within the uncertainty associated with representing any GCR reference field with discrete ion beams in the laboratory, given current facility constraints. A single reference field for deep space missions is subsequently identified. Third, a preliminary approach for selecting beams at NSRL to simulate the designated reference field is presented. This approach is not a final design for the GCR simulator, but rather a single step within a broader design strategy. It is shown that the beam selection methodology is tied directly to the reference environment, allows facility constraints to be incorporated, and may be adjusted to account for additional constraints imposed by biological or animal care considerations. The major biology questions are not addressed herein but are discussed in a companion paper published in the present issue of this journal. Drawbacks of the proposed methodology are discussed

  14. Unconventional superconductors under a rotating magnetic field. I. Density of states and specific heat

    NASA Astrophysics Data System (ADS)

    Vorontsov, A. B.; Vekhter, I.

    2007-06-01

    We develop a fully microscopic theory for the calculations of the angle-dependent properties of unconventional superconductors under a rotated magnetic field. We employ the quasiclassical Eilenberger equations and use a variation of the Brandt-Pesch-Tewordt (BPT) method to obtain a closed-form solution for the Green’s function. The equations are solved self-consistently for quasi-two-dimensional dx2-y2(dxy) superconductors with the field rotated in the basal plane. The solution is used to determine the density of states and the specific heat. We find that applying the field along the gap nodes may result in minima or maxima in the angle-dependent specific heat, depending on the location in the T-H plane. This variation is attributed to the scattering of the quasiparticles on vortices, which depends on both the field and the quasiparticle energy, and is beyond the reach of the semiclassical approximation. We investigate the anisotropy across the T-H phase diagram and compare our results with the experiments on heavy fermion CeCoIn5 .

  15. Wnt signaling balances specification of the cardiac and pharyngeal muscle fields.

    PubMed

    Mandal, Amrita; Holowiecki, Andrew; Song, Yuntao Charlie; Waxman, Joshua S

    2017-02-01

    Canonical Wnt/β-catenin (Wnt) signaling plays multiple conserved roles during fate specification of cardiac progenitors in developing vertebrate embryos. Although lineage analysis in ascidians and mice has indicated there is a close relationship between the cardiac second heart field (SHF) and pharyngeal muscle (PM) progenitors, the signals underlying directional fate decisions of the cells within the cardio-pharyngeal muscle field in vertebrates are not yet understood. Here, we examined the temporal requirements of Wnt signaling in cardiac and PM development. In contrast to a previous report in chicken embryos that suggested Wnt inhibits PM development during somitogenesis, we find that in zebrafish embryos Wnt signaling is sufficient to repress PM development during anterior-posterior patterning. Importantly, the temporal sensitivity of dorso-anterior PMs to increased Wnt signaling largely overlaps with when Wnt signaling promotes specification of the adjacent cardiac progenitors. Furthermore, we find that excess early Wnt signaling can cell autonomously promote expansion of the first heart field (FHF) progenitors at the expense of PM and SHF within the anterior lateral plate mesoderm (ALPM). Our study provides insight into an antagonistic developmental mechanism that balances the sizes of the adjacent cardiac and PM progenitor fields in early vertebrate embryos. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Classical Impossibility of DT Reactor below 120 KeV and Design of DT Micro-Reactor for Land Mine Detection by Fast Neutron Gamma Activation.

    NASA Astrophysics Data System (ADS)

    Maglich, B. C.

    1996-11-01

    There is an industrial demand for a multipurpose 20 KeV, 100 cc DT micro reactor but charge exchange renders beam-heated DT reactors unworkable [1-3] or classically impossible [4] below 120 keV. We describe a 150 KeV autocollider in Alternating Gradient Strong Focusing Migma field [5] based on cryo-cooled NiSn, designed for midplane B=5 T [6], stabilized by nonlinear electron oscillations effect [7]. Ion density: 3 × 10^12cm-3/cc. Method to enhance N^14 ``signature'' of explosive in γ-spectrum by a factor of 10 will be presented. 1. B. Maglich et al., presentations to CTR/AEC, 6/18/74 and 11/3/74; 2. J. Treglio, J. Appl. Phys., 46, 4344 (1975); 3. Decision (based on ref. 2) to cancel Tokamak T-30 program in USSR (1/7/76); 4. D.W. Scott and B.C. Maglich, this Meeting, Sess. 5.1.1.1 TFTR; 5. J.P. Blewett, Part. Acc. 34, 13 (1990) U.S.Pat. 5,034,183; 6. D.A. Gross, GE Corp. R and D Center; 7. Phys. Rev. Lett. 70, 299 (1993) U.S.Pat. 4,788,024.

  17. Recommendations for Guidelines for Environment-Specific Magnetic-Field Measurements, Rapid Program Engineering Project #2

    SciTech Connect

    Electric Research and Management, Inc.; IIT Research Institute; Magnetic Measurements; Survey Research Center, University of California; T. Dan Bracken, Inc.

    1997-03-11

    The purpose of this project was to document widely applicable methods for characterizing the magnetic fields in a given environment, recognizing the many sources co-existing within that space. The guidelines are designed to allow the reader to follow an efficient process to (1) plan the goals and requirements of a magnetic-field study, (2) develop a study structure and protocol, and (3) document and carry out the plan. These guidelines take the reader first through the process of developing a basic study strategy, then through planning and performing the data collection. Last, the critical factors of data management, analysis reporting, and quality assurance are discussed. The guidelines are structured to allow the researcher to develop a protocol that responds to specific site and project needs. The Research and Public Information Dissemination Program (RAPID) is based on exposure to magnetic fields and the potential health effects. Therefore, the most important focus for these magnetic-field measurement guidelines is relevance to exposure. The assumed objective of an environment-specific measurement is to characterize the environment (given a set of occupants and magnetic-field sources) so that information about the exposure of the occupants may be inferred. Ideally, the researcher seeks to obtain complete or "perfect" information about these magnetic fields, so that personal exposure might also be modeled perfectly. However, complete data collection is not feasible. In fact, it has been made more difficult as the research field has moved to expand the list of field parameters measured, increasing the cost and complexity of performing a measurement and analyzing the data. The guidelines address this issue by guiding the user to design a measurement protocol that will gather the most exposure-relevant information based on the locations of people in relation to the sources. We suggest that the "microenvironment" become the base unit of area in a study, with

  18. Quantum bound on the specific entropy in strongly coupled scalar field theory

    SciTech Connect

    Aparicio Alcalde, M.; Menezes, G.; Svaiter, N. F.

    2008-06-15

    We discuss the (g{sub 0}{phi}{sup p}){sub d} self-interacting scalar field theory, in the strong-coupling regime. We assume the presence of macroscopic boundaries confining the field in a hypercube of side L. We also consider that the system is in thermal equilibrium at temperature {beta}{sup -1}. For spatially bounded free fields, the Bekenstein bound states that the specific entropy satisfies the inequality (S/E)<2{pi}R, where R stands for the radius of the smallest sphere that circumscribes the system. Employing the strong-coupling perturbative expansion, we obtain the renormalized mean energy E and entropy S for the system up to the order (g{sub 0}){sup -(2/p)}, presenting an analytical proof that the specific entropy also satisfies in some situations a quantum bound. Defining {epsilon}{sub d}{sup (r)} as the renormalized zero-point energy for the free theory per unit length, the dimensionless quantity {xi}=({beta}/L) and h{sub 1}(d) and h{sub 2}(d) as positive analytic functions of d, for the case of high temperature, we get that the specific entropy satisfies (S/E)<2{pi}R(h{sub 1}(d)/h{sub 2}(d)){xi}. When considering the low-temperature behavior of the specific entropy, we have (S/E)<2{pi}R(h{sub 1}(d)/{epsilon}{sub d}{sup (r)}){xi}{sup 1-d}. Therefore the sign of the renormalized zero-point energy can invalidate this quantum bound. If the renormalized zero-point energy is a positive quantity, at intermediate temperatures and in the low-temperature limit, there is a quantum bound.

  19. Soil specific re-calibration of water content sensors for a field-scale sensor network

    NASA Astrophysics Data System (ADS)

    Gasch, Caley K.; Brown, David J.; Anderson, Todd; Brooks, Erin S.; Yourek, Matt A.

    2015-04-01

    Obtaining accurate soil moisture data from a sensor network requires sensor calibration. Soil moisture sensors are factory calibrated, but multiple site specific factors may contribute to sensor inaccuracies. Thus, sensors should be calibrated for the specific soil type and conditions in which they will be installed. Lab calibration of a large number of sensors prior to installation in a heterogeneous setting may not be feasible, and it may not reflect the actual performance of the installed sensor. We investigated a multi-step approach to retroactively re-calibrate sensor water content data from the dielectric permittivity readings obtained by sensors in the field. We used water content data collected since 2009 from a sensor network installed at 42 locations and 5 depths (210 sensors total) within the 37-ha Cook Agronomy Farm with highly variable soils located in the Palouse region of the Northwest United States. First, volumetric water content was calculated from sensor dielectric readings using three equations: (1) a factory calibration using the Topp equation; (2) a custom calibration obtained empirically from an instrumented soil in the field; and (3) a hybrid equation that combines the Topp and custom equations. Second, we used soil physical properties (particle size and bulk density) and pedotransfer functions to estimate water content at saturation, field capacity, and wilting point for each installation location and depth. We also extracted the same reference points from the sensor readings, when available. Using these reference points, we re-scaled the sensor readings, such that water content was restricted to the range of values that we would expect given the physical properties of the soil. The re-calibration accuracy was assessed with volumetric water content measurements obtained from field-sampled cores taken on multiple dates. In general, the re-calibration was most accurate when all three reference points (saturation, field capacity, and wilting

  20. The Conformer Specific Rotational Spectrum of 3-PHENYLPROPIONITRILE Utilizing Strong Field Coherence Breaking

    NASA Astrophysics Data System (ADS)

    Fritz, Sean; Hernandez-Castillo, Alicia O.; Abeysekera, Chamara; Zwier, Timothy S.

    2017-06-01

    The 8-18 GHz conformer specific rotational spectrum of gauche- and anti-3-phenylpropionitrile (C6H5-CH2-CH2-CN) conformers has been recorded using the strong field coherence breaking (SFCB) technique [1] with a modified line picking scheme for multiple selective excitations (MSE). As the recombination product of benzyl and cyanomethyl resonance-stabilized radicals, 3-phenylpropionitrile is a likely component of the complex organics in Titan's atmosphere, motivating its structural characterization. Details of the modified line picking scheme, hyperfine constants and relative population ratios of the two conformers will be presented. [1] A.O Hernandez-Castillo, Chamara Abeysekera, Brian M. Hays, Timothy S. Zwier, "Broadband Multi-Resonant Strong Field Coherence Breaking as a Tool for Single Isomer Microwave Spectroscopy." J. Chem. Phys. 145, 114203 (2016).

  1. Specific feature of magnetooptical images of stray fields of magnets of various geometrical shapes

    NASA Astrophysics Data System (ADS)

    Ivanov, V. E.; Koveshnikov, A. V.; Andreev, S. V.

    2017-08-01

    Specific features of magnetooptical images (MOIs) of stray fields near the faces of prismatic hard magnetic elements have been studied. Attention has primarily been focused on MOIs of fields near faces oriented perpendicular to the magnetic moment of hard magnetic elements. With regard to the polar sensitivity, MOIs have practically uniform brightness and geometrically they coincide with the figures of the bases of the elements. With regard to longitudinal sensitivity, MOIs consist of several sectors, the number of which is determined by the number of angles of the image. Each angle is divided by the bisectrix into two sectors of different brightnesses; therefore, the MOI of a triangular magnet consists of three sectors. A rectangle consists of four sectors separated by the bisectrices of the interior angles. In all types of figures, these lines converge at the center of the figure and form a singular point of the source or sink type.

  2. Anisotropic Finite Element Modeling Based on a Harmonic Field for Patient-Specific Sclera

    PubMed Central

    Zheng, Wanqiu; Zou, Beiji

    2017-01-01

    Purpose. This study examined the influence of anisotropic material for human sclera. Method. First, the individual geometry of patient-specific sclera was reproduced from a laser scan. Then, high quality finite element modeling of individual sclera was performed using a convenient automatic hexahedral mesh generator based on harmonic field and integrated with anisotropic material assignment function. Finally, comparison experiments were designed to investigate the effects of anisotropy on finite element modeling of sclera biomechanics. Results. The experimental results show that the presented approach can generate high quality anisotropic hexahedral mesh for patient-specific sclera. Conclusion. The anisotropy shows significant differences for stresses and strain distribution and careful consideration should be given to its use in biomechanical FE studies. PMID:28271067

  3. Comparing intra- and inter-specific effects on litter decomposition in an old-field ecosystem

    SciTech Connect

    Crutsinger, Greg; Sanders, Dr. Nathan James; Classen, Aimee T

    2009-09-01

    Plant species can differ in the quantity and quality of leaf litter they produce, and many studies have examined whether plant species diversity affects leaf-litter decomposition and nutrient release. A growing number of studies have indicated that intra-specific variation within plant species can also affect key ecosystem processes. However, the relative importance of intra- versus inter-specific variation for the functioning of ecosystems remains poorly known. Here, we investigate the effects of intra-specific variation in a dominant old-field plant species, tall goldenrod (Solidago altissima), and inter-specific variation among goldenrod species on litter quality, decomposition, and nitrogen (N) release. We found that the nutrient concentration of leaf litter varied among genotypes, which translated into 50% difference in decomposition rates. Variation among other goldenrod species in decomposition rate was more than twice that of genetic variation within S. altissima. Furthermore, by manipulating litterbags to contain 1, 3, 6, or 9 genotypes, we found that S. altissima genotype identity had much stronger effects than did genotypic diversity on leaf-litter quality, decomposition, and N release. Taken together, these results suggest that the order of ecological importance for controlling leaf-litter decomposition and N release dynamics is plant species identitygenotype identity>genotypic diversity.

  4. Combination neutron-gamma ray detector

    DOEpatents

    Stuart, Travis P.; Tipton, Wilbur J.

    1976-10-26

    A radiation detection system capable of detecting neutron and gamma events and distinguishing therebetween. The system includes a detector for a photomultiplier which utilizes a combination of two phosphor materials, the first of which is in the form of small glass beads which scintillate primarily in response to neutrons and the second of which is a plastic matrix which scintillates in response to gammas. A combination of pulse shape and pulse height discrimination techniques is utilized to provide an essentially complete separation of the neutron and gamma events.

  5. Neutron-gamma techniques for planetary exploration

    NASA Technical Reports Server (NTRS)

    Johnson, R. G.; Evans, L. G.; Trombka, J. I.

    1979-01-01

    Chemical analysis of planetary surfaces is necessary for the understanding of the origin and evolutionary processes of the solar system. Orbital lunar geochemical experiments performed during the Apollo 15 and 16 demonstrated that even with a low neutron flux (fast and thermal), reliable results could be extracted. The possibility of using a compact 14 MeV neutron generator for geochemical analysis of planetary surfaces, comets and asteroids is currently studied. This method allows the determination of bulk chemical composition, even in the presence of an atmosphere. This would be possible on the surface of Venus, for example, where alternate methods such as sample return are impractical. This method can be used for continuous monitoring of elemental abundances from a roving vehicle, for example, on the surface of Mars.

  6. A Competency Based, Field Centered, Systems Approach to Elementary Teacher Education. Volume I: Overview and Specifications. Final Report.

    ERIC Educational Resources Information Center

    Schalock, H. Del, Ed.; Hale, James R., Ed.

    This main volume (SP 002 155-SP 002 180 comprise the appendixes to this volume) explains the ComField (competency based, field centered) Model--a systems approach to the education of elementary school teachers which entails specifications (1) for instruction and (2) for management of the instructional program. In an overview, the ComField Model is…

  7. Genus-Specific Primers for Study of Fusarium Communities in Field Samples

    PubMed Central

    Edel-Hermann, Véronique; Gautheron, Nadine; Durling, Mikael Brandström; Kolseth, Anna-Karin; Steinberg, Christian; Persson, Paula; Friberg, Hanna

    2015-01-01

    Fusarium is a large and diverse genus of fungi of great agricultural and economic importance, containing many plant pathogens and mycotoxin producers. To date, high-throughput sequencing of Fusarium communities has been limited by the lack of genus-specific primers targeting regions with high discriminatory power at the species level. In the present study, we evaluated two Fusarium-specific primer pairs targeting translation elongation factor 1 (TEF1). We also present the new primer pair Fa+7/Ra+6. Mock Fusarium communities reflecting phylogenetic diversity were used to evaluate the accuracy of the primers in reflecting the relative abundance of the species. TEF1 amplicons were subjected to 454 high-throughput sequencing to characterize Fusarium communities. Field samples from soil and wheat kernels were included to test the method on more-complex material. For kernel samples, a single PCR was sufficient, while for soil samples, nested PCR was necessary. The newly developed primer pairs Fa+7/Ra+6 and Fa/Ra accurately reflected Fusarium species composition in mock DNA communities. In field samples, 47 Fusarium operational taxonomic units were identified, with the highest Fusarium diversity in soil. The Fusarium community in soil was dominated by members of the Fusarium incarnatum-Fusarium equiseti species complex, contradicting findings in previous studies. The method was successfully applied to analyze Fusarium communities in soil and plant material and can facilitate further studies of Fusarium ecology. PMID:26519387

  8. Genus-Specific Primers for Study of Fusarium Communities in Field Samples.

    PubMed

    Karlsson, Ida; Edel-Hermann, Véronique; Gautheron, Nadine; Durling, Mikael Brandström; Kolseth, Anna-Karin; Steinberg, Christian; Persson, Paula; Friberg, Hanna

    2015-10-30

    Fusarium is a large and diverse genus of fungi of great agricultural and economic importance, containing many plant pathogens and mycotoxin producers. To date, high-throughput sequencing of Fusarium communities has been limited by the lack of genus-specific primers targeting regions with high discriminatory power at the species level. In the present study, we evaluated two Fusarium-specific primer pairs targeting translation elongation factor 1 (TEF1). We also present the new primer pair Fa+7/Ra+6. Mock Fusarium communities reflecting phylogenetic diversity were used to evaluate the accuracy of the primers in reflecting the relative abundance of the species. TEF1 amplicons were subjected to 454 high-throughput sequencing to characterize Fusarium communities. Field samples from soil and wheat kernels were included to test the method on more-complex material. For kernel samples, a single PCR was sufficient, while for soil samples, nested PCR was necessary. The newly developed primer pairs Fa+7/Ra+6 and Fa/Ra accurately reflected Fusarium species composition in mock DNA communities. In field samples, 47 Fusarium operational taxonomic units were identified, with the highest Fusarium diversity in soil. The Fusarium community in soil was dominated by members of the Fusarium incarnatum-Fusarium equiseti species complex, contradicting findings in previous studies. The method was successfully applied to analyze Fusarium communities in soil and plant material and can facilitate further studies of Fusarium ecology.

  9. Compound specific isotope analysis to investigate pesticide degradation in lysimeter experiments at field conditions

    NASA Astrophysics Data System (ADS)

    Ryabenko, Evgenia; Elsner, Martin; Bakkour, Rani; Hofstetter, Thomas; Torrento, Clara; Hunkeler, Daniel

    2015-04-01

    The frequent detection of organic micropollutants such as pesticides, consumer care products or pharmaceuticals in water is an increasing concern for human and ecosystem health. Degradation analysis of these compounds can be challenging in complex systems due to the fact that metabolites are not always found and mass balances frequently cannot be closed. Many abiotic and biotic degradation pathways cause, however, distinct isotope fractionation, where light isotopes are transferred preferentially from the reactant to the product pool (normal isotope fractionation). Compound-specific isotope analysis (CSIA) of multiple elements is a particularly powerful method to evaluate organic micropollutant transformation, because it can even give pathway-specific isotope fractionation (1,2). Available CSIA field studies, however, have focused almost exclusively on volatile petroleum and chlorinated hydrocarbons, which are present in high concentrations in the environment and can be extracted easily from water for GC-IRMS analysis. In the case of micropollutants, such as pesticides, CSIA in more challenging since it needs to be conducted at lower concentrations and requires pre-concentration, purification and high chromatographic performance (3). In this study we used lysimeters experiments to analyze transformation of atrazine, acetochlor, metolachlor and chloridazone by studying associated isotope fractionation. The project combines a) analytical method development for CSIA, b) identification of pathways of micropollutant degradation and c) quantification of transformation processes under field condition. The pesticides were applied both, at the soil surface and below the top soil under field-relevant concentrations in May 2014. After typical irrigation of the lysimeters, seepage water was collected in 50L bottles and stored for further SPE and CSIA. Here we present the very first result of a) analytical method development, b) improvement of SPE methods for complex pesticide

  10. Anisotropic polymer composites synthesized by immobilizing cellulose nanocrystal suspensions specifically oriented under magnetic fields.

    PubMed

    Tatsumi, Mio; Kimura, Fumiko; Kimura, Tsunehisa; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2014-12-08

    Novel polymer composites reinforced with an oriented cellulose nanocrystal (CNC) assembly were prepared from suspensions of CNC in aqueous 2-hydroxyethyl methacrylate (HEMA) via magnetic field application to the suspensions followed by polymerization treatment. The starting suspensions used at ∼6 wt % CNC separated into an upper isotropic phase and a lower anisotropic (chiral nematic) one in the course of quiescent standing. A static or rotational magnetic field was applied to the isolated isotropic and anisotropic phases. UV-induced polymerization of HEMA perpetuated the respective states of magnetic orientation invested for the CNC dispersions to yield variously oriented CNC/poly(2-hydroxyethyl methacrylate) composites. The structural characterization was carried out by use of X-ray diffractometry and optical and scanning electron microscopy. The result indicated that CNCs were aligned in the composites distinctively according to the static or rotational magnetic application when the anisotropic phases were used, whereas such a specific CNC orientation was not appreciable when the isotropic phases were sampled. This marks out effectiveness of a coherent response of CNCs in the mesomorphic assembly. In dynamic mechanical experiments in tensile or compressive mode, we observed a clear mechanical anisotropy for the polymer composites synthesized from wholly anisotropic suspensions under static or rotational magnetization. The higher modulus (in compression) was detected for a composite reinforced by locking-in the uniaxial CNC alignment attainable through conversion of the initial chiral nematic phase into a nematic phase in the rotational magnetic field.

  11. Significant Refinement of Protein Structure Models Using a Residue-Specific Force Field.

    PubMed

    Xun, Sangni; Jiang, Fan; Wu, Yun-Dong

    2015-04-14

    An important application of all-atom explicit-solvent molecular dynamics (MD) simulations is the refinement of protein structures from low-resolution experiments or template-based modeling. A critical requirement is that the native structure is stable with the force field. We have applied a recently developed residue-specific force field, RSFF1, to a set of 30 refinement targets from recent CASP experiments. Starting from their experimental structures, 1.0 μs unrestrained simulations at 298 K retain most of the native structures quite well except for a few flexible terminals and long internal loops. Starting from each homology model, a 150 ns MD simulation at 380 K generates the best RMSD improvement of 0.85 Å on average. The structural improvements roughly correlate with the RMSD of the initial homology models, indicating possible consistent structure refinement. Finally, targets TR614 and TR624 have been subjected to long-time replica-exchange MD simulations. Significant structural improvements are generated, with RMSD of 1.91 and 1.36 Å with respect to their crystal structures. Thus, it is possible to achieve realistic refinement of protein structure models to near-experimental accuracy, using accurate force field with sufficient conformational sampling.

  12. Topographic Distribution of Stimulus-Specific Adaptation across Auditory Cortical Fields in the Anesthetized Rat

    PubMed Central

    Nieto-Diego, Javier; Malmierca, Manuel S.

    2016-01-01

    Stimulus-specific adaptation (SSA) in single neurons of the auditory cortex was suggested to be a potential neural correlate of the mismatch negativity (MMN), a widely studied component of the auditory event-related potentials (ERP) that is elicited by changes in the auditory environment. However, several aspects on this SSA/MMN relation remain unresolved. SSA occurs in the primary auditory cortex (A1), but detailed studies on SSA beyond A1 are lacking. To study the topographic organization of SSA, we mapped the whole rat auditory cortex with multiunit activity recordings, using an oddball paradigm. We demonstrate that SSA occurs outside A1 and differs between primary and nonprimary cortical fields. In particular, SSA is much stronger and develops faster in the nonprimary than in the primary fields, paralleling the organization of subcortical SSA. Importantly, strong SSA is present in the nonprimary auditory cortex within the latency range of the MMN in the rat and correlates with an MMN-like difference wave in the simultaneously recorded local field potentials (LFP). We present new and strong evidence linking SSA at the cellular level to the MMN, a central tool in cognitive and clinical neuroscience. PMID:26950883

  13. Retesting The Validity Of A Specific Field Test For Judo Training

    PubMed Central

    Santos, Luis; González, Vicente; Iscar, Marta; Brime, Juan I.; Fernández-Río, Javier; Rodríguez, Blanca; Montoliu, Mª Ángeles

    2011-01-01

    The main goal of this research project was to retest the validity of a specifically designed judo field test (Santos Test) in a different group of judokas. Eight (n=8) national-level male judokas underwent laboratory and field testing. The mean data (mean +/− SD) obtained in the laboratory tests was: HRmax: 200 ± 4.0 beats × min−1, VO2 max: 52.8 ± 7.9 ± ml × kg−1 × min−1, lactate max: 12 ± 2.5 mmol × l−1, HR at the anaerobic threshold: 174.2 ± 9.4 beats × min−1, percentage of maximum heart rate at which the anaerobic threshold appears: 87 ± 3.6 %, lactate threshold: 4.0 ± 0.2 mmol × l−1, and RPE: 17.2 ± 1.0. The mean data obtained in the field test (Santos) was: HRmax: 201.3 ± 4.1 beats × min−1, VO2 max: 55.6 ± 5.8 ml × kg−1 × min−1, lactate max: 15.6 ± 2.8 mmol × l−1, HR at the anaerobic threshold: 173.2 ± 4.3 beats × min−1, percentage of maximum heart rate at which the anaerobic threshold appears: 86 ± 2.5 %, lactate threshold: 4.0 ± 0.2 mmol × l−1, and RPE: 16.7 ± 1.0. There were no significant differences between the data obtained on both tests in any of the parameters, except for maximum lactate concentration. Therefore, the Santos test can be considered a valid tool specific for judo training. PMID:23486994

  14. Retesting the validity of a specific field test for judo training.

    PubMed

    Santos, Luis; González, Vicente; Iscar, Marta; Brime, Juan I; Fernández-Río, Javier; Rodríguez, Blanca; Montoliu, M Ángeles

    2011-09-01

    The main goal of this research project was to retest the validity of a specifically designed judo field test (Santos Test) in a different group of judokas. Eight (n=8) national-level male judokas underwent laboratory and field testing. The mean data (mean +/- SD) obtained in the laboratory tests was: HRmax: 200 ± 4.0 beats × min(-1), VO2 max: 52.8 ± 7.9 ± ml × kg(-1) × min(-1), lactate max: 12 ± 2.5 mmol × l(-1), HR at the anaerobic threshold: 174.2 ± 9.4 beats × min(-1), percentage of maximum heart rate at which the anaerobic threshold appears: 87 ± 3.6 %, lactate threshold: 4.0 ± 0.2 mmol × l(-1), and RPE: 17.2 ± 1.0. The mean data obtained in the field test (Santos) was: HRmax: 201.3 ± 4.1 beats × min(-1), VO2 max: 55.6 ± 5.8 ml × kg(-1) × min(-1), lactate max: 15.6 ± 2.8 mmol × l(-1), HR at the anaerobic threshold: 173.2 ± 4.3 beats × min(-1), percentage of maximum heart rate at which the anaerobic threshold appears: 86 ± 2.5 %, lactate threshold: 4.0 ± 0.2 mmol × l(-1), and RPE: 16.7 ± 1.0. There were no significant differences between the data obtained on both tests in any of the parameters, except for maximum lactate concentration. Therefore, the Santos test can be considered a valid tool specific for judo training.

  15. Low-Temperature Specific-Heat Measurements in Magnetic Fields: Superconducting and Magnetic Oxides

    NASA Astrophysics Data System (ADS)

    Phillips, Norman E.

    2000-03-01

    Two different thermometer/sample configurations have been used for specific-heat measurements in the range 0.25-120K, 0-9T with the effect of magnetic field on the thermometer calibrations eliminated by enclosing the thermometers in superconducting shields. A modified heat-pulse technique at the lower temperatures and a continuous heating technique at higher temperatures, together with relatively large sample sizes, gave good accuracy and precision. The measurements are illustrated by results on superconducting and magnetic oxides: The specific heat of YBa_2Cu_3O7 shows the presence of singlet-ground-state spin-2 and spin-1/2 paramagnetic centers. Contributions expected for d-wave pairing, a T^2 term for H = 0, and an H^1/2T term for H > 0 conformed to a predicted scaling relation. For (La,Sr)_2CuO_4, a lower concentration of paramagnetic centers allowed a more direct identification of the d-wave effects. For two samples of (Ba,K)BiO3 the normal-state conduction-electron contributions and the magnitudes of the broadened specific-heat anomalies at Tc are consistent with strong-coupling BCS theory. For (Nd,Sr)MnO3 the interaction between the two spin systems produces a molecular-field ordering of the Nd spins, a broadening of the ordering anomaly for the Mn spins, and an enhanced T-proportional term. For La_0.65Ca_0.35MnO3 ferromagnetic spin-wave and conduction-electron contributions were resolved.

  16. Constructing the 'gender-specific body': A critical discourse analysis of publications in the field of gender-specific medicine.

    PubMed

    Annandale, Ellen; Hammarström, Anne

    2011-11-01

    Gender-specific medicine, a new and increasingly influential ethos within medical research and practice, has received little critical attention to date. The objective of this article is to critically examine the attributes of gender-specific medicine as imparted by its advocates. Through a critical discourse analysis of its two leading academic journals, we identify five interrelated discourses: of male/female difference; of hegemonic biology; of men's disadvantages; of biological and social reductionism; and of the fragmented body. Together these comprise a master discourse of the 'gender-specific body'. The discourse of the 'gender-specific body' is discussed in relation to the current neoliberal political agenda which frames healthcare as a market good and locates health and illness in individual bodies rather than in the wider social arrangements of society. We argue that the 'gender-specific body' threatens not only to turn back the clock to a vision of the biological body as fixed and determinate, but to extend this ever deeper into the social imagination. Lost in the process is any meaningful sense of the human body as a relatively open system which develops in interaction with its social world. We propose that, as it gains momentum, the 'gender-specific body' is likely progressively to circumscribe our thinking about the health of women and men in potentially problematic ways.

  17. Demonstration Using Field Collections that Argentina Fall Armyworm Populations Exhibit Strain-specific Host Plant Preferences.

    PubMed

    Murúa, M Gabriela; Nagoshi, Rodney N; Dos Santos, Daniel A; Hay-Roe, Mirian M; Meagher, Robert L; Vilardi, J C

    2015-10-01

    Spodoptera frugiperda, the fall armyworm, is a major economic pest throughout the Western Hemisphere of corn (maize), cotton, sorghum, and a variety of agricultural grasses and vegetable crops. Studies in the United States, the Caribbean, and Brazil demonstrated the existence of two subpopulations (previously designated "host strains") that differ in their choice of plant host. Specifically, the corn strain is preferentially found in corn and sorghum, while the rice strain is dominant in rice, turf grass, and alfalfa. However, inconsistent results were reported in surveys of fall armyworm in Argentina, with some indicating that the host plant preferences of the two strains might be compromised or even nonexistent. If correct, this would complicate efforts to control this pest by considerably expanding the range of habitats that would have to be considered as potential sources for fall armyworm infestations in specific crops. A reexamination of Argentine fall armyworm, this time with field collections rather than the laboratory colonies used in previous studies, confirmed the existence of the two strains and their host preferences. Specifically, the corn strain was consistently the majority population infesting corn and was usually so in sorghum, while the rice strain was predominant in pasture/turf grasses and alfalfa. The one outlier was a collection from rice, which had a corn strain majority. Overall, the data were generally consistent with strain behaviors observed in other areas of the Western Hemisphere.

  18. A soil-specific agro-ecological strategy for sustainable production in Argentina farm fields

    NASA Astrophysics Data System (ADS)

    Zamora, Martin; Barbera, Agustin; Castro-Franco, Mauricio; Hansson, Alejandro; Domenech, Marisa

    2017-04-01

    The continuous increment of frequencies and doses of pesticides, glyphosate and fertilizers, the deterioration of the structure, biotic balance and fertility of soils and the ground water pollution are characteristics of the current Argentinian agricultural model. In this context, agro-ecological innovations are needed to develop a real sustainable agriculture, enhancing the food supply. Precision agriculture technologies can strengthen the expansion of agro-ecological farming in experimental farm fields. The aim of this study was to propose a soil-specific agro-ecological strategy for sustainable production at field scale focused on the use of soil sensors and digital soil mapping techniques. This strategy has been developed in 15 hectares transition agro-ecological farm field, located at Barrow Experimental Station (Lat:-38.322844, Lon:-60.25572) Argentina. The strategy included five steps: (i) to measure apparent electrical conductivity (ECa) and elevation within agro-ecological farm field; (ii) to apply a clustering method using MULTISPATI-PCA algorithm to delimitate three soil-specific zones (Z1, Z2 and Z3); (iii) to determine three soil sampling points by zone, using conditioned Latin hypercube method, in addition to elevation and ECa as auxiliary information; (iv) to collect soil samples at 2-10 cm depth in each point and to determine in laboratory: total organic carbon content (TOC), cation-exchange capacity (CEC), pH and phosphorus availability (P-Bray). In addition, soil bulk density (SBD) was measured at 0-20 cm depth. Finally, (v) according to each soil-specific zone, a management strategy was recommended. Important differences in soil properties among zones could suggest that the strategy developed was able to apply an agro ecological soil-specific practice management. pH and P-Bray were significantly (p<0.05) higher in Z1 than in Z2 and Z3. TOC did not show significant difference among zones, but it was higher in Z2. CEC was significantly (p<0

  19. Correction factors for ionization chamber dosimetry in CyberKnife: Machine-specific, plan-class, and clinical fields

    SciTech Connect

    Gago-Arias, Araceli; Antolin, Elena; Fayos-Ferrer, Francisco; Simon, Rocio; Gonzalez-Castano, Diego M.; Palmans, Hugo; Sharpe, Peter; Gomez, Faustino; Pardo-Montero, Juan

    2013-01-15

    Purpose: The aim of this work is the application of the formalism for ionization chamber reference dosimetry of small and nonstandard fields [R. Alfonso, P. Andreo, R. Capote, M. S. Huq, W. Kilby, P. Kjaell, T. R. Mackie, H. Palmans, K. Rosser, J. Seuntjens, W. Ullrich, and S. Vatnitsky, 'A new formalism for reference dosimetry of small and nonstandard fields,' Med. Phys. 35, 5179-5186 (2008)] to the CyberKnife robotic radiosurgery system. Correction factors for intermediate calibration fields, a machine-specific reference field (msr) and two plan-class specific reference fields (pcsr), have been studied. Furthermore, the applicability of the new formalism to clinical dosimetry has been analyzed through the investigation of two clinical treatments. Methods: PTW31014 and Scanditronix-Wellhofer CC13 ionization chamber measurements were performed for the fields under investigation. Absorbed dose to water was determined using alanine reference dosimetry, and experimental correction factors were calculated from alanine to ionization chamber readings ratios. In addition, correction factors were calculated for the intermediate calibration fields and one of the clinical treatment fields using the Monte Carlo method and these were compared with the experimental values. Results: Overall correction factors deviating from unity by approximately 2% were obtained from both measurements and simulations, with values below and above unity for the studied intermediate calibration fields and clinical fields for the ionization chambers under consideration. Monte Carlo simulations yielded correction factors comparable with those obtained from measurements for the machine-specific reference field, although differences from 1% to 3.3% were observed between measured and calculated correction factors for the composite intermediate calibration fields. Dose distribution inhomogeneities are thought to be responsible for such discrepancies. Conclusions: The differences found between overall

  20. Characterisation of neutron fields at Cernavoda NPP.

    PubMed

    Cauwels, Vanessa; Vanhavere, Filip; Dumitrescu, Dorin; Chirosca, Alecsandru; Hager, Luke; Million, Marc; Bartz, James

    2013-04-01

    Near a nuclear reactor or a fuel container, mixed neutron/gamma fields are very common, necessitating routine neutron dosimetry. Accurate neutron dosimetry is complicated by the fact that the neutron effective dose is strongly dependent on the neutron energy and the direction distribution of the neutron fluence. Neutron field characterisation is indispensable if one wants to obtain a reliable estimate for the neutron dose. A measurement campaign at CANDU nuclear power plant located in Cernavoda, Romania, was set up to characterise the neutron fields in four different locations and to investigate the behaviour of different neutron personal dosemeters. This investigation intends to assist in choosing a suitable neutron dosimetry system at this nuclear power plant.

  1. Magnetic Nanoparticles with High Specific Absorption Rate at Low Alternating Magnetic Field

    PubMed Central

    Kekalo, K.; Baker, I.; Meyers, R.; Shyong, J.

    2015-01-01

    This paper describes the synthesis and properties of a new type of magnetic nanoparticle (MNP) for use in the hyperthermia treatment of tumors. These particles consist of 2–4 nm crystals of gamma-Fe2O3 gathered in 20–40 nm aggregates with a coating of carboxymethyl-dextran, producing a zetasize of 110–120 nm. Despite their very low saturation magnetization (1.5–6.5 emu/g), the specific absorption rate (SAR) of the nanoparticles is 22–200 W/g at applied alternating magnetic field (AMF) with strengths of 100–500 Oe at a frequency of 160 kHz. PMID:26884816

  2. Plant-specific responses to zinc contamination in a semi-field lysimeter and on hydroponics.

    PubMed

    Bernhard, Roland; Verkleij, Jos A C; Nelissen, Hans J M; Vink, Jos P M

    2005-11-01

    The species Agrostis stolonifera, Brassica napus and Trifolium repens representing different ecological strategies, were selected to study the effect of Zn contamination on Zn tolerance, uptake and accumulation patterns. Parallel tests were carried out with increasing concentrations of Zn in a semi-field lysimeter and hydroponics in the climate chamber. A significant reduction in biomass production or root length and an increase in shoot Zn concentration was observed for all species at increasing external Zn concentrations. However, shoot biomass production, Zn tolerance and Zn accumulation differed significantly among the tested species. The results in both experimental set-ups were quite similar concerning Zn tolerance and accumulation and improved the validity of the findings. The rather specific responses of the different plant species to Zn contamination interfere with the more generic approach used in risk assessment studies. Maximum amounts of Zn in shoot are not likely to cause a risk to herbivores.

  3. The Specific Heat of UGe_2: Effects of Pressure and Magnetic Field

    NASA Astrophysics Data System (ADS)

    Fisher, R. A.; Bouquet, F.; Lashley, J. C.; Phillips, N. E.; Huxley, A.; Flouquet, J.

    2003-03-01

    At ambient pressure (P) UGe2 undergoes transitions from paramagnetic, to ferromagnetic (FM), to coupled charge-density wave (CDW) spin-density wave (SDW) phases on cooling. Within a narrow range of P, and at temperatures (T) below ˜0.7 K (but depending on sample quality), superconductivity (SC) coexists with both the CDW-SDW and FM phases. The γT term for the specific heat (C) increases with increasing P, most rapidly between ˜1 and ˜1.4 GPa, the region in which SC develops, then approaches a constant value at 1.8 GPa. The γT term decreases in a magnetic field. In the CDW-SDW region of the phase diagram C includes an exponential term that represents the CDW-SDW and decreases in a magnetic field. The electronic entropy increases rapidly in a narrow interval of P in the vicinity of the CDW-SDW transition, which suggests that it might be broadened first order. A transition to SC is not observed to 0.35 K in the range of P where it is expected to occur, but there are upturns in C/T, absent at other P's, that suggest the onset of SC.

  4. Evaluation of Specific Absorption Rate as a Dosimetric Quantity for Electromagnetic Fields Bioeffects

    PubMed Central

    Panagopoulos, Dimitris J.; Johansson, Olle; Carlo, George L.

    2013-01-01

    Purpose To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. Methods We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect. Results We find that: a) The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b) All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c) The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured. Conclusions SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc) which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar uncertainty to predict

  5. Wireless communication fields and non-specific symptoms of ill health: a literature review.

    PubMed

    Röösli, Martin; Hug, Kerstin

    2011-05-01

    This is an update of a previous systematic review on the association between radiofrequency electromagnetic field (RF-EMF) exposure and health-related quality of life that included studies published before August 2007 [1]. Since then, nine randomized trials addressed short-term exposures from close-to-body RF-EMF sources such as mobile phones, and two observational studies investigated the effects of mobile phone use on health-related quality of life. Six randomized trials addressed short-term far-field exposure arising, for instance, from mobile phone base stations, and eight studies evaluated the effects of environmental far-field RF-EMF exposure. In most of the randomized trials, no exposure-response association was observed. The sporadically reported associations did not show a consistent pattern regarding the type of symptoms or the direction of the effects (increase/decrease). Similarly, most of the recent observational studies did not show associations between RF-EMF exposure and non-specific symptoms. However, the exposure gradients were small and possible exposure misclassification is a limitation of these studies. Longitudinal studies as well as studies in children and adolescents are scarce. In summary, recent research did not indicate health-related quality of life to be affected by RF-EMF exposure in our everyday environment. Furthermore, none of the studies showed that individuals with self-reported electromagnetic hypersensitivity (EHS) were more susceptible to RF-EMF than the rest of the population. Nevertheless, the rapid technological development and anticipated increase in exposure levels warrant the conduct of further longitudinal studies. Due to the widespread use of wireless communication technologies potential adverse health effects would have major public health consequences.

  6. Evaluation of specific absorption rate as a dosimetric quantity for electromagnetic fields bioeffects.

    PubMed

    Panagopoulos, Dimitris J; Johansson, Olle; Carlo, George L

    2013-01-01

    To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect. WE FIND THAT: a) The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b) All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c) The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured. SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc) which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar uncertainty to predict the biological effect due to non-linearity.

  7. Neutrons, gamma rays, and beta particles interactions with IIaO films flown on Astro I and Astro II and comparison with IIaO flown on the get-away-special STS-7

    NASA Technical Reports Server (NTRS)

    Hammond, Ernest C., Jr.; Peters, Kevein; Boone, Kevin

    1995-01-01

    The current requirements for the Laboratory for Astronomy and Solar Physics, sends rocket satellites and in the near future will involve flights in the shuttle to the upper reaches of the Earth's atmosphere where they will be subjected to the atomic particles and electromagnetic radiation produced by the Sun and other cosmic radiation. It is therefore appropriate to examine the effect of neutrons, gamma rays, beta particles, and X-rays on the film currently being used by the Laboratory for current and future research requirements. It is also hoped by examining these particles in their effect that we will have simulated the space environment of the rockets, satellites, and shuttles. Several samples of the IIaO film were exposed to a neutron howitzer with a source energy of approximately 106 neutrons/steradians. We exposed several samples of the film to a 10 second blast of neutrons in both metal and plastic containers which exhibited higher density readings which indicated the possibility of some secondary nuclear interactions between neutrons and the aluminum container. The plastic container showed some variations at the higher densities. Exposure of the samples of IIaO film to a neutron beam of approximately 10 neutrons per steradians for eight minutes produces approximately a 13% difference in the density readings of the dark density grids. It is not noticeable that at the lighter density grid the neutrons have minimal effects, but on a whole the trend of the eight minute exposed IIaO film density grids at the darker end had a 7.1% difference than the control. Further analysis is anticipated by increasing the exposure time. Two sets of film were exposed to a beta source in a plastic container. The beta source was placed at the bottom so that the cone of rays striking the film would be conical for a period of seven days. It was observed in the films, designated 4a and 4b, a dramatic increase in the grid densities had occurred. The attenuation of beta particles due

  8. Nociceptive Local Field Potentials Recorded from the Human Insula Are Not Specific for Nociception

    PubMed Central

    Liberati, Giulia; Klöcker, Anne; Safronova, Marta M.; Ferrão Santos, Susana; Ribeiro Vaz, Jose-Geraldo; Raftopoulos, Christian; Mouraux, André

    2016-01-01

    The insula, particularly its posterior portion, is often regarded as a primary cortex for pain. However, this interpretation is largely based on reverse inference, and a specific involvement of the insula in pain has never been demonstrated. Taking advantage of the high spatiotemporal resolution of direct intracerebral recordings, we investigated whether the human insula exhibits local field potentials (LFPs) specific for pain. Forty-seven insular sites were investigated. Participants received brief stimuli belonging to four different modalities (nociceptive, vibrotactile, auditory, and visual). Both nociceptive stimuli and non-nociceptive vibrotactile, auditory, and visual stimuli elicited consistent LFPs in the posterior and anterior insula, with matching spatial distributions. Furthermore, a blind source separation procedure showed that nociceptive LFPs are largely explained by multimodal neural activity also contributing to non-nociceptive LFPs. By revealing that LFPs elicited by nociceptive stimuli reflect activity unrelated to nociception and pain, our results confute the widespread assumption that these brain responses are a signature for pain perception and its modulation. PMID:26734726

  9. Validation of a field test for the non-invasive determination of badminton specific aerobic performance

    PubMed Central

    Wonisch, M; Hofmann, P; Schwaberger, G; von Duvillard, S P; Klein, W

    2003-01-01

    Aim: To develop a badminton specific test to determine on court aerobic and anaerobic performance. Method: The test was evaluated by using a lactate steady state test. Seventeen male competitive badminton players (mean (SD) age 26 (8) years, weight 74 (10) kg, height 179 (7) cm) performed an incremental field test on the badminton court to assess the heart rate turn point (HRTP) and the individual physical working capacity (PWCi) at 90% of measured maximal heart rate (HRmax). All subjects performed a 20 minute steady state test at a workload just below the PWCi. Results: Significant correlations (p<0.05) for Pearson's product moment coefficient were found between the two methods for HR (r = 0.78) and velocity (r = 0.93). The HR at the PWCi (176 (5.5) beats/min) was significantly lower than the HRTP (179 (5.5) beats/min), but no significant difference was found for velocity (1.44 (0.3) m/s, 1.38 (0.4) m/s). The constant exercise test showed steady state conditions for both HR (175 (9) beats/min) and blood lactate concentration (3.1 (1.2) mmol/l). Conclusion: The data indicate that a valid determination of specific aerobic and anaerobic exercise performance for the sport of badminton is possible without HRTP determination. PMID:12663351

  10. Class-specific weighting for Markov random field estimation: application to medical image segmentation.

    PubMed

    Monaco, James P; Madabhushi, Anant

    2012-12-01

    Many estimation tasks require Bayesian classifiers capable of adjusting their performance (e.g. sensitivity/specificity). In situations where the optimal classification decision can be identified by an exhaustive search over all possible classes, means for adjusting classifier performance, such as probability thresholding or weighting the a posteriori probabilities, are well established. Unfortunately, analogous methods compatible with Markov random fields (i.e. large collections of dependent random variables) are noticeably absent from the literature. Consequently, most Markov random field (MRF) based classification systems typically restrict their performance to a single, static operating point (i.e. a paired sensitivity/specificity). To address this deficiency, we previously introduced an extension of maximum posterior marginals (MPM) estimation that allows certain classes to be weighted more heavily than others, thus providing a means for varying classifier performance. However, this extension is not appropriate for the more popular maximum a posteriori (MAP) estimation. Thus, a strategy for varying the performance of MAP estimators is still needed. Such a strategy is essential for several reasons: (1) the MAP cost function may be more appropriate in certain classification tasks than the MPM cost function, (2) the literature provides a surfeit of MAP estimation implementations, several of which are considerably faster than the typical Markov Chain Monte Carlo methods used for MPM, and (3) MAP estimation is used far more often than MPM. Consequently, in this paper we introduce multiplicative weighted MAP (MWMAP) estimation-achieved via the incorporation of multiplicative weights into the MAP cost function-which allows certain classes to be preferred over others. This creates a natural bias for specific classes, and consequently a means for adjusting classifier performance. Similarly, we show how this multiplicative weighting strategy can be applied to the MPM

  11. Determination of canine dose conversion factors in mixed neutron and gamma radiation fields. Technical report

    SciTech Connect

    Torres, B.A.; Bhatt, R.C.; Myska, J.C.; Holland, B.K.

    1996-07-01

    The primary objective of mixed-field neutron/gamma radiation dosimetry in canine irradiation experiments conducted at the Armed Forces Radiobiology Research Institute (AFRRI) is to determine the absorbed midline tissue dose (MLT) at the region of interest in the canine. A dose conversion factor (DCF) can be applied to free-in-air (FIA) dose measurements to estimate the MLT doses to canines. This report is a summary of the measured DCFs that were used to determine the MLT doses in canines at AFRRI from 1979 to 1992.

  12. Variable rate application of nematicides on cotton fields: a promising site-specific management strategy.

    PubMed

    Ortiz, Brenda V; Perry, Calvin; Sullivan, Dana; Lu, Ping; Kemerait, Robert; Davis, Richard F; Smith, Amanda; Vellidis, George; Nichols, Robert

    2012-03-01

    specific application of nematicides based on management zones, although this approach might not be economically beneficial in fields with little variability in soil texture.

  13. Effect of heat exposure on thermoregulation and hockey-specific response time in field hockey goalkeepers.

    PubMed

    Malan, Marcelle; Dawson, Brian; Goodman, Carmel; Peeling, Peter

    2010-05-01

    This study examined the thermoregulatory responses in field hockey goalkeepers during games (Part A), and assessed the effect of heat stress on hockey-specific response time (Part B). In Part A, core temperature (T(c)), skin temperature (T(sk)), body mass, fluid consumption and heart rate (HR) responses of six goalkeepers during two premier level club games in the Western Australian (winter) hockey season were recorded. Part B assessed the same measures, plus a response time test on four goalkeepers playing a simulated game inside a climate chamber in cool (COOL: 20 degrees C, 40% RH) and hot (HOT: 35 degrees C, 40% RH) conditions. In Part A, the mean (+/-SD) T(c) and T(sk) measured in games was 38.49+/-0.20 degrees C and 34.99+/-0.99 degrees C, with increases from baseline of 1.34+/-0.19 degrees C and 1.08+/-0.30 degrees C, respectively. Most of the increase in T(c) resulted from the pre-game warm-up. In Part B, T(c) and T(sk) only increased significantly (p<0.05) from baseline in the HOT condition (0.62+/-0.18 degrees C and 1.61+/-0.82 degrees C, respectively). Response time was significantly slower (0.87+/-0.14s, p<0.01) after heat exposure, compared to COOL (0.75+/-0.15s), but the number of correct responses was not affected. For optimal performance, careful attention should be given to strategies to limit T(c) increases in field hockey goalkeepers during matches.

  14. Context-specific influence of water temperature on brook trout growth rates in the field

    USGS Publications Warehouse

    Xu, C.; Letcher, B.H.; Nislow, K.H.

    2010-01-01

    1. Modelling the effects of climate change on freshwater fishes requires robust field-based estimates accounting for interactions among multiple factors.2. We used data from an 8-year individual-based study of a wild brook trout (Salvelinus fontinalis) population to test the influence of water temperature on season-specific growth in the context of variation in other environmental (i.e. season, stream flow) or biotic factors (local brook trout biomass density and fish age and size) in West Brook, a third-order stream in western Massachusetts, U.S.A.3. Changes in ambient temperature influenced individual growth rates. In general, higher temperatures were associated with higher growth rates in winter and spring and lower growth rates in summer and autumn. However, the effect of temperature on growth was strongly context-dependent, differing in both magnitude and direction as a function of season, stream flow and fish biomass density.4. We found that stream flow and temperature had strong and complex interactive effects on trout growth. At the coldest temperatures (in winter), high stream flows were associated with reduced trout growth rates. During spring and autumn and in typical summers (when water temperatures were close to growth optima), higher flows were associated with increased growth rates. In addition, the effect of flow at a given temperature (the flow-temperature interaction) differed among seasons.5. Trout density negatively affected growth rate and had strong interactions with temperature in two of four seasons (i.e. spring and summer) with greater negative effects at high temperatures.6. Our study provided robust, integrative field-based estimates of the effects of temperature on growth rates for a species which serves as a model organism for cold-water adapted ectotherms facing the consequences of environmental change. Results of the study strongly suggest that failure to derive season-specific estimates, or to explicitly consider interactions with

  15. A SUGGESTED CURRICULUM GUIDE FOR ELECTRO-MECHANICAL TECHNOLOGY ORIENTED SPECIFICALLY TO THE COMPUTER AND BUSINESS MACHINE FIELDS. INTERIM REPORT.

    ERIC Educational Resources Information Center

    LESCARBEAU, ROLAND F.; AND OTHERS

    A SUGGESTED POST-SECONDARY CURRICULUM GUIDE FOR ELECTRO-MECHANICAL TECHNOLOGY ORIENTED SPECIFICALLY TO THE COMPUTER AND BUSINESS MACHINE FIELDS WAS DEVELOPED BY A GROUP OF COOPERATING INSTITUTIONS, NOW INCORPORATED AS TECHNICAL EDUCATION CONSORTIUM, INCORPORATED. SPECIFIC NEEDS OF THE COMPUTER AND BUSINESS MACHINE INDUSTRY WERE DETERMINED FROM…

  16. A SUGGESTED CURRICULUM GUIDE FOR ELECTRO-MECHANICAL TECHNOLOGY ORIENTED SPECIFICALLY TO THE COMPUTER AND BUSINESS MACHINE FIELDS. INTERIM REPORT.

    ERIC Educational Resources Information Center

    LESCARBEAU, ROLAND F.; AND OTHERS

    A SUGGESTED POST-SECONDARY CURRICULUM GUIDE FOR ELECTRO-MECHANICAL TECHNOLOGY ORIENTED SPECIFICALLY TO THE COMPUTER AND BUSINESS MACHINE FIELDS WAS DEVELOPED BY A GROUP OF COOPERATING INSTITUTIONS, NOW INCORPORATED AS TECHNICAL EDUCATION CONSORTIUM, INCORPORATED. SPECIFIC NEEDS OF THE COMPUTER AND BUSINESS MACHINE INDUSTRY WERE DETERMINED FROM…

  17. Ligula intestinalis (Cestoda: Diphyllobothriidae) in Kenya: a field investigation into host specificity and behavioural alterations.

    PubMed

    Britton, J R; Jackson, M C; Harper, D M

    2009-09-01

    Within the distribution of Ligula intestinalis, a tapeworm affecting freshwater fishes, there are genetically distinct and well-separated phylogenetic clusters. East Africa is represented by a single monophyletic clade which is understudied compared with Euro-Mediterranean clades. The present field investigation in the Lake Baringo and Naivasha catchments, Kenya, revealed that this L. intestinalis clade was highly host-specific, present in only 2 of 12 fishes examined; Barbus paludinosus in Naivasha and Barbus lineomaculatus in Baringo. In infected fish, cestodes comprised up to 20% of body weight. Only 1 parasite was recorded per fish, a contrast to infected fishes in Europe where mixed infections are commonplace. In B. lineomaculatus in Baringo, only fish of greater than 64 mm in length were parasitized. The highest parasite prevalence was recorded in fish of 70-77 mm in length, and reduced for lengths of 78-84 mm. Parasitized fish were significantly associated with a particular type of habitat, occurring most frequently in shallow littoral areas, and being absent from open water and rocky shore habitats. Uninfected fish were present in all habitats. This relationship between spatial occupancy and parasite prevalence is suggested to arise from behavioural alterations induced by the parasite that promotes completion of the parasite life cycle.

  18. Compound-Specific Stable Isotope Analysis: Implications in Hexachlorocyclohexane in-vitro and Field Assessment.

    PubMed

    Kohli, Puneet; Richnow, Hans H; Lal, Rup

    2017-03-01

    Assessment of biotic and abiotic degradation reactions by studying the variation in stable isotopic compositions of organic contaminants in contaminated soil and aquifers is being increasingly considered during the last two decades with development of Compound specific stable isotope analysis (CSIA) technique. CSIA has been recognized as a potential tool for evaluating both qualitative and quantitative degradation with measurement of shifts in isotope ratios of contaminants and their degradation products as its basis. Amongst a wide variety of environmental pollutants including monoaromatics, chlorinated ethenes and benzenes etc., it is only recently that its efficacy is being tested for assessing biodegradation of a noxious pollutant namely hexachlorocyclohexane (HCH), by pure microbial cultures as well as directly at the field site. Anticipating the increase in demand of this technique for monitoring the microbial degradation along with natural attenuation, this review highlights the basic problems associated with HCH contamination emphasizing the applicability of emerging CSIA technique to absolve the major bottlenecks in assessment of HCH. To this end, the review also provides a brief overview of this technique with summarizing the recent revelations put forward by both in vitro and in situ studies by CSIA in monitoring HCH biodegradation.

  19. The Application Of Microbial Enhanced Oil Recovery On Unconventional Oil: A Field Specific Approach

    NASA Astrophysics Data System (ADS)

    Goodman, Sean; Millar, Andrew; Allison, Heather; McCarthy, Alan

    2014-05-01

    A substantial amount of the world's recoverable oil reserves are made from unconventional or heavy resources. However, great difficulty has been had in recovering this oil after primary and secondary recovery methods have been employed. Therefore, tertiary methods such as microbial enhanced oil recovery (MEOR) have been employed. MEOR involves the use of bacteria and their metabolic products to alter the oil properties or rock permeability within a reservoir in order to promote the flow of oil. Although MEOR has been trialed in the past with mixed outcomes, its feasibility on heavier oils has not been demonstrated. The aim of this study is to show that MEOR can be successfully applied to unconventional oils. By using an indigenous strain of bacteria isolated from a reservoir of interest and applied to field specific microcosms, we will look into the effect of these bacteria compared to variant inoculums to identify which mechanisms of action the bacteria are using to improve recovery. Using this information, we will be able to identify genes of interest and groups of bacteria that may be beneficial for MEOR and look accurately identify favorable bacteria within a reservoir.

  20. Variational state specific solvent models for excited states from time dependent self-consistent field methods

    NASA Astrophysics Data System (ADS)

    Bjorgaard, Josiah; Velizhanin, Kirill; Tretiak, Sergei

    2015-03-01

    The effect of a dielectric environment on a molecule can be profound, causing changes in nuclear configuration and electronic structure. Quantum chemical simulation of a solute-solvent system can be prohibitively expensive due to the large number of degrees of freedom attributed to the solvent. To remedy this, the solvent can be treated as a dielectric cavity. Mutual polarization of the solute and solvent must be considered for accurate treatment of an optically excited state (ES) with a state-specific solvent model (SSM). In vacuum, time dependent self-consistent field (TD-SCF) methods (e,g, TD-HF, TD-DFT) give variational excitation energies. With the well known Z-vector equation, a variational ES energy is used to explore the ES potential energy surface (PES) with analytical gradients. Modification of the standard TD-SCF eigensystem to accommodate a SSM creates a nonlinear TD-SCF equation with non-variational excitation energies. This prevents analytical gradients from being formulated so that the ES PES cannot be explored. Here, we show how a variational formulation of existing SSMs can be derived from a Lagrangian formalism and give numerical results for the variability of calculated quantities. Model dynamics using SSMs are showcased.

  1. Modulation of Osteogenesis in Human Mesenchymal Stem Cells by Specific Pulsed Electromagnetic Field Stimulation

    PubMed Central

    Tsai, Ming-Tzu; Li, Wan-Ju; Tuan, Rocky S.; Chang, Walter H.

    2009-01-01

    Human mesenchymal stem cells (hMSCs) are a promising candidate cell type for regenerative medicine and tissue engineering applications by virtue of their capacity for self-renewal and multipotent differentiation. Our intent was to characterize the effect of pulsed electromagnetic fields (PEMFs) on the proliferation and osteogenic differentiation of hMSCs in vitro. hMSCs isolated from the bone marrow of adult patients were cultured with osteogenic medium for up to 28 days and exposed to daily PEMF stimulation with single, narrow 300 μs quasi-rectangular pulses with a repetition rate of 7.5 Hz. Relatively greater cell numbers were observed at late stages of osteogenic culture with PEMF exposure. The production of alkaline phosphatase (ALP), an early marker of osteogenesis, was significantly enhanced at day 7 with PEMF treatment in both basal and osteogenic cultures as compared to untreated controls. Furthermore, the expressions of other early osteogenic genes, including Runx2/Cbfa1 and ALP, were also partially modulated by PEMF exposure, indicating that osteogenesis in hMSCs was associated with the specific PEMF stimulation. Based on ALP and alizarin red S staining, the accumulation of ALP protein produced by the hMSCs as well as calcium deposits reached their highest levels at day 28. Our results indicate that extremely low frequency PEMF stimulation may play a modulating role in hMSC osteogenesis. Taken together, these findings provide insights on the development of PEMF as an effective technology for regenerative medicine. PMID:19274753

  2. Field-based evaluation of a male-specific (F+) RNA coliphage ...

    EPA Pesticide Factsheets

    Fecal contamination of water poses a significant risk to public health due to the potential presence of pathogens, including enteric viruses. Thus, sensitive, reliable and easy to use methods for the detection of microorganisms are needed to evaluate water quality. In this study, we performed a field evaluation of an anion-exchange resin based platform to concentrate F-RNA coliphages (fecal/enteric virus indicators) from diverse fecally impacted environmental waters. In this platform, F-RNA coliphages are adsorbed to anion-exchange resin and direct nucleic acid isolation is performed, yielding a sample amenable to real-time reverse transcriptase PCR detection. Matrix-dependent inhibition was evaluated using known quantities of spiked F-RNA coliphage genogroups GI, GII, GII and GIV. Detection was successful in 97%, 72%, 85% and 98% of the samples for spiked F-RNA coliphage GI, GII, GIII and GIV, respectively, and was differentially affected by inhibitory properties specific to each water sample. No association between inhibition and the water samples’ physicochemical properties was apparent. Parallel evaluations of the spiked samples with internal amplification control (IAC) reactions (a widely used control to assess inhibition) demonstrated that IAC reaction inhibition was not agreement with that observed for spiked samples, suggesting that testing of spiked samples allows for better assessments of matrix-dependent inhibition. Additionally, the anion-

  3. Compound-Specific Carbon and Hydrogen Isotope Analysis - Field Evidence of MTBE Bioremediation

    NASA Astrophysics Data System (ADS)

    Kuder, T.; Kolhatkar, R. V.; Philp, P.; Wilson, J. T.; Landmeyer, J. E.; Allen, J.

    2002-12-01

    Compound-specific stable isotope analysis allows opportunity to determine the isotopic ratios of individual contaminants. The technique has been applied to confirm biodegradation in studies of chlorinated solvents and recently BTEX, MTBE and TBA. Chemical reactions (including bio- and inorganic degradation) tend to favor molecules with the lighter isotopic species (e.g., 12C, 1H), resulting with enrichment of the unreacted substrate in the heavier isotopic species (13C, D), referred to as kinetic isotopic fractionation, so that the extent of fractionation may be used as a proxy for biodegradation. Processes such as volatilization, sorption etc., result in minimal degree of fractionation and do not interfere with the isotopic signal due to biodegradation. The results presented here show the first successful applications of compound-specific isotope analysis to understanding MTBE biodegradation in the field, at both aerobic and anaerobic sites. Observed fractionations suggest that two different biodegradation pathways may be involved. At a number of anaerobic locations major fractionation effects were observed for both C and H; enrichment factors Ÿnfor both elements were approaching or exceeding -10. A laboratory microcosm study using an enrichment culture yielded similar results (C data only). A characteristic feature of these sites was the presence of high concentrations of TBA. Conversely, at a number of sites, the C composition remained stable with little fractionation and stayed within the analytical precision range or changed minimally, while H displayed significant fractionation in excess of 60 per mil. Moderate agreement of the data with Rayleigh fractionation model was observed, suggesting that biodegradation effect was distorted by variability at the source or the plume was not homogeneous. The enrichment factor calculated for these data is similar to the one Ÿnpublished for aerobic microcosm of MTBE-degrading culture from Vandenberg AFB by Gray et al

  4. Removal of F-specific RNA bacteriophages in artificial recharge of groundwater--a field study.

    PubMed

    Niemi, R M; Kytövaara, A; Pääkkönen, J; Lahti, K

    2004-01-01

    Artificial recharge of groundwater offers a semi-natural means to produce raw water for drinking-water plants. Surface water works are increasingly being replaced by artificial groundwater works in Finland. Two municipalities, one serving 30,000 and the other 170,000 inhabitants, have considered filtering river water through eskers for the production of potable water. In this study the removal of bacteriophages during infiltration of river water was estimated, for the evaluation of treatment adequacy in a field study. A 5-m-deep column of sand was constructed and used to mimic the percolating phase in infiltration. An artificial esker was constructed on the riverbank by isolating a 2-m-wide, 2-m-deep and 18-m-long bed of coarse sand with plastic. The sand bed represented the saturated zone. River water was pumped at a rate of 40 L/h to the sand column. The river water was spiked with F+ specific RNA phage MS2 by adding phage suspension during one week at an average concentration of 4.3 x 10(9) PFU/mL. Samples for phage assays were taken during one month, from four sampling sites, on the basis of detention time as estimated by a tracer experiment with sodium chloride. The median count of MS2 for percolated water was 2.4 x 10(5) PFU/mL, representing a 96.7% reduction. During the passage of 6 m in the saturated zone, a further reduction of 98.5% occurred. During the passage from 6 m to 12 m the additional reduction was 99.97%. The overall reduction was between 6 and 7 log10 units. The removal of MS2 phages was rather efficient, although the esker material was coarse, mainly sandy, gravel.

  5. Technical Note: Evaluation of plastic scintillator detector for small field stereotactic patient-specific quality assurance.

    PubMed

    Qin, Yujiao; Gardner, Stephen J; Kim, Joshua; Huang, Yimei; Wen, Ning; Doemer, Anthony; Chetty, Indrin J

    2017-07-17

    To evaluate the performance of a commercial plastic scintillator detector (PSD) for small-field stereotactic patient-specific quality assurance (QA) measurements using flattening-filter-free beam. A total of 10 spherical targets [volume range: (0.03 cc-2 cc)] were planned with two techniques: (a) dynamic conformal arc (DCA-10 plans) and (b) volumetric modulated arc therapy (VMAT-10 plans). All plans were generated using Varian Eclipse treatment planning system, and AcurosXB v.13 algorithm in 1.0 mm grid size. Additionally, 14 previously treated cranial and spine SRS plans were evaluated [6 DCA, 8 VMAT, volume range: (0.04 cc-119.02 cc)]. Plan modulation was quantified via two metrics: MU per prescription dose (MU/Rx) and Average Leaf Pair Opening (ALPO). QA was performed on the Varian Edge linear accelerator equipped with HDMLC. Three detectors were used: (a) PinPoint ion chamber (PTW; active volume 0.015 cc), (b) Exradin W1 PSD (Standard Imaging; active volume 0.002 cc), and (c) Gafchromic EBT3 film (Ashland). PinPoint chamber and PSD were positioned perpendicular to beam axis in a Lucy phantom (Standard Imaging); films were placed horizontally capturing the coronal plane. PSD, film, and PinPoint chamber measured average differences of 1.00 ± 1.54%, 1.30 ± 1.69%, and -0.66 ± 2.36%, respectively, compared to AcurosXB dose calculation. As the target volume decreased, PinPoint chamber measured lower doses (maximum -5.07% at 0.07 cc target), while PSD and film measured higher doses (2.87% and 2.54% at 0.03 cc target) than AcurosXB. Film agreed with the benchmark detector PSD by an average difference of 0.31 ± 1.20%, but suffered from larger uncertainty; PinPoint chamber underestimated dose by more than 4% for targets smaller than 0.2 cc. Taking PSD as the measurement standard, DCA plans achieved good QA results across all volumes studied, with an average of -0.07 ± 0.89%; for VMAT plans, PSD measured consistently higher dose (1.95 ± 1

  6. The GIPC1-Akt1 Pathway Is Required for the Specification of the Eye Field in Mouse Embryonic Stem Cells.

    PubMed

    La Torre, Anna; Hoshino, Akina; Cavanaugh, Christopher; Ware, Carol B; Reh, Thomas A

    2015-09-01

    During early patterning of the neural plate, a single region of the embryonic forebrain, the eye field, becomes competent for eye development. The hallmark of eye field specification is the expression of the eye field transcription factors (EFTFs). Experiments in fish, amphibians, birds, and mammals have demonstrated largely conserved roles for the EFTFs. Although some of the key signaling events that direct the synchronized expression of these factors to the eye field have been elucidated in fish and frogs, it has been more difficult to study these mechanisms in mammalian embryos. In this study, we have used two different methods for directed differentiation of mouse embryonic stem cells (mESCs) to generate eye field cells and retina in vitro to test for a role of the PDZ domain-containing protein GIPC1 in the specification of the mammalian eye primordia. We find that the overexpression of a dominant-negative form of GIPC1 (dnGIPC1), as well as the downregulation of endogenous GIPC1, is sufficient to inhibit the development of eye field cells from mESCs. GIPC1 interacts directly with IGFR and participates in Akt1 activation, and pharmacological inhibition of Akt1 phosphorylation mimics the dnGIPC1 phenotype. Our data, together with previous studies in Xenopus, support the hypothesis that the GIPC1-PI3K-Akt1 pathway plays a key role in eye field specification in vertebrates.

  7. The GIPC1-Akt1 pathway is required for the specification of the eye field in mouse embryonic stem cells

    PubMed Central

    La Torre, Anna; Hoshino, Akina; Cavanaugh, Christopher; Ware, Carol B.; Reh, Thomas A.

    2015-01-01

    During early patterning of the neural plate, a single region of the embryonic forebrain, the eye field, becomes competent for eye development. The hallmark of eye field specification is the expression of the eye field transcription factors (EFTFs). Experiments in fish, amphibians, birds and mammals have demonstrated largely conserved roles for the EFTFs. Although some of the key signaling events that direct the synchronized expression of these factors to the eye field have been elucidated in fish and frogs, it has been more difficult to study these mechanisms in mammalian embryos. In this study, we have used two different methods for directed differentiation of mouse embryonic stem cells (mESCs) to generate eye field cells and retina in vitro to test for a role of the PDZ domain-containing protein GIPC1 in the specification of the mammalian eye primordia. We find that the overexpression of a dominant-negative form of GIPC1 (dnGIPC1), as well as the downregulation of endogenous GIPC1, is sufficient to inhibit the development of eye field cells from mESCs. GIPC1 interacts directly with IGFR and participates in Akt1 activation, and pharmacological inhibition of Akt1 phosphorylation mimics the dnGIPC1 phenotype. Our data, together with previous studies in Xenopus, support the hypothesis that the GIPC1-PI3K-Akt1 pathway plays a key role in eye field specification in vertebrates. PMID:26013465

  8. Geochemical Specific Characters of the Oil and the Origin of the Oil and Gas Fields

    NASA Astrophysics Data System (ADS)

    Gottikh, Rimma; Pisotskiy, Bogdan; Plotnikova, Irina

    2010-05-01

    and porous rocks. The high metal content of carbonaceous substances and their compositional variations governed by homogenisation temperatures of the inclusions suggest that they are not the products of the decomposition of oil fields. The constant presence of uranium in the fluid and its differentiation products allows the tracing of the systems' migration ways from the crystalline basement to oil-saturated reservoir zones of the sedimentary cover The known geochemical properties of bitumen and oil - high platinum content, specific distributions of rare earth elements, that are not characteristic of the upper crust formations, as well as 143Nd/144Nd and 87Sr/86Sr isotopic compounds, which are out of balance with the organic matter of sedimentary rocks - suggest that hydrocarbons are accumulated in the presence of cooling high-alkalinity mafite-ultramafite intrusions. This logically corresponds to the distribution of seismic anomalies and magnetic and gravity fields in the consolidated crust below the various petroleum fields (for example, South Tatarstan and Nepsky arches of the Romashkino and Verkhne-Chonskoye oil fields). The acquired geochemical and thermodynamic characteristics of the reduced fluids and their differentiation products from the crystalline basement and the sedimentary cover of the southern Siberian and eastern East European platforms indicate that these were formed outside of the sedimentary cover and that the migration was directed upwards. The analysis of the magmatic evolution on platforms reveals its alkaline trend due to the impeded degassing of magmatic sources at depth and the inflow of new doses of alkaline fluids or melts into them. Further evolution of the zones of partial melting of the substratum led, in the authors' view, to the generation of oil-forming fluids and their transportation into the Earth's upper crust. Their interaction with the surrounding rocks in turn led to the formation of oil accumulations. Thus, oil is the product

  9. High-Field fMRI for Human Applications: An Overview of Spatial Resolution and Signal Specificity

    PubMed Central

    Olman, Cheryl A; Yacoub, Essa

    2011-01-01

    In the last decade, dozens of 7 Tesla scanners have been purchased or installed around the world, while 3 Tesla systems have become a standard. This increased interest in higher field strengths is driven by a demonstrated advantage of high fields for available signal-to-noise ratio (SNR) in the magnetic resonance signal. Functional imaging studies have additional advantages of increases in both the contrast and the spatial specificity of the susceptibility based BOLD signal. One use of this resultant increase in the contrast to noise ratio (CNR) for functional MRI studies at high field is increased image resolution. However, there are many factors to consider in predicting exactly what kind of resolution gains might be made at high fields, and what the opportunity costs might be. The first part of this article discusses both hardware and image quality considerations for higher resolution functional imaging. The second part draws distinctions between image resolution, spatial specificity, and functional specificity of the fMRI signals that can be acquired at high fields, suggesting practical limitations for attainable resolutions of fMRI experiments at a given field, given the current state of the art in imaging techniques. Finally, practical resolution limitations and pulse sequence options for studies in human subjects are considered. PMID:22216080

  10. Magnetic-field dependence of Schottky specific heat in the 1/1 Zn-Sc-Tm approximant

    NASA Astrophysics Data System (ADS)

    Dolinšek, J.

    2017-02-01

    The analysis of low-temperature specific heat of rare-earth (RE)-containing quasicrystals and periodic approximants and consequent interpretation of their electronic properties in the T → 0 limit is frequently hampered by the Schottky effect, where crystalline electric fields lift degeneracy of the RE-ion Hund’s rule ground state and introduce additional contribution to the specific heat. When the low-temperature specific heat C is analyzed in the C/T versus T 2 scale, the Schottky effect (a single-ion property in a system of non-interacting electrons) and the electron-electron interactions both yield a very similar upturn in the T → 0 limit. The origin of the upturn can be unraveled from the magnetic-field dependence of the low-temperature specific heat.

  11. Species-specific photosynthetic responses of four coniferous seedlings to open-field experimental warming

    NASA Astrophysics Data System (ADS)

    Han, S.; Yoon, S. J.; Yoon, T. K.; Han, S. H.; Lee, J.; Lee, D.; Kim, S.; Hwang, J.; Cho, M.; Son, Y.

    2014-12-01

    Temperature increase under climate change is expected to affect photosynthesis of tree species. Biochemical models generally suggest that the elevated temperature increases the photosynthetic carbon fixation, however, many opposing results were reported as well. We aimed to examine the photosynthetic responses of four coniferous seedlings to projected future temperature increase, by conducting an open-field warming experiment. Experimental warming set-up using infra-red heater was built in 2011 and the temperature in warming plots has been regulated to be consistently 3oC higher than that of control plots. The seeds of Abies holophylla (AH), A. koreana (AK), Pinus densiflora (PD), and P. koraiensis (PK) were planted in each 1 m × 1 m plot (n=3) in April, 2012. Monthly net photosynthetic rates (Pn; μmol CO2 m-2 s-1) of 1-year-old seedlings (n=9) from June to November, 2013 were measured using CIRAS-2 (PP-Systems, UK) and photosynthetic parameters (the apparent quantum yield; ф; µmol CO2 mol-1, the dark respiration rate; Rd; µmol CO2 mol-1, and the light compensation point; LCP; µmol mol-1 s-1) were also calculated from the light-response curve of photosynthesis in August, 2013. Chlorophyll contents were measured using DMSO extraction method. Monthly Pn was generally higher for PD and decreased for AK in warmed plots than in control plots (Fig. 1). Pn of AK and PK did not show any significant difference, however, Pn of PK in October and November increased by experimental warming. Pn of PD also showed the highest increase in November and this distinct increase of Pn in autumn might be caused by delayed cessation of photosynthesis by temperature elevation. ф and Rd in warmed plots were higher for PD and lower for AK, while LCP did not significantly differ by treatments for all species. Because ф is considered to be related to the efficiency of harvesting and using light, the change in ф might have caused the response of Pn to warming in this study. Decreases

  12. Field experiments to evaluate host plant specificity of prospective agents of Onopordum acanthium in Bulgaria

    USDA-ARS?s Scientific Manuscript database

    Scotch thistle, Onopordum acanthium, is an invasive alien weed in North America that originates from Europe. Previous field observations in Bulgaria have confirmed the presence of prospective biological control agents including Cassida rubiginosa, Chaetostomella cylindrica, Eublemma amoena, Larinus ...

  13. A Method to Teach Age-Specific Demography with Field Grown Rapid Cycling "Brassica rapa" (Wisconsin Fast Plants)

    ERIC Educational Resources Information Center

    Kelly, Martin G.; Terrana, Sebastian

    2004-01-01

    In this paper, we demonstrate that rapid cycling "Brassica rapa" (Wisconsin Fast Plants) can be used in inquiry-based, student ecological fieldwork. We are the first to describe age-specific survival for field-grown Fast Plants and identify life history traits associated with individual survival. This experiment can be adapted by educators as a…

  14. Glaucoma progression detection: agreement, sensitivity, and specificity of expert visual field evaluation, event analysis, and trend analysis.

    PubMed

    Antón, Alfonso; Pazos, Marta; Martín, Belén; Navero, José Manuel; Ayala, Miriam Eleonora; Castany, Marta; Martínez, Patricia; Bardavío, Javier

    2013-01-01

    To assess sensitivity, specificity, and agreement among automated event analysis, automated trend analysis, and expert evaluation to detect glaucoma progression. This was a prospective study that included 37 eyes with a follow-up of 36 months. All had glaucomatous disks and fields and performed reliable visual fields every 6 months. Each series of fields was assessed with 3 different methods: subjective assessment by 2 independent teams of glaucoma experts, glaucoma/guided progression analysis (GPA) event analysis, and GPA (visual field index-based) trend analysis. Kappa agreement coefficient between methods and sensitivity and specificity for each method using expert opinion as gold standard were calculated. The incidence of glaucoma progression was 16% to 18% in 3 years but only 3 cases showed progression with all 3 methods. Kappa agreement coefficient was high (k=0.82) between subjective expert assessment and GPA event analysis, and only moderate between these two and GPA trend analysis (k=0.57). Sensitivity and specificity for GPA event and GPA trend analysis were 71% and 96%, and 57% and 93%, respectively. The 3 methods detected similar numbers of progressing cases. The GPA event analysis and expert subjective assessment showed high agreement between them and moderate agreement with GPA trend analysis. In a period of 3 years, both methods of GPA analysis offered high specificity, event analysis showed 83% sensitivity, and trend analysis had a 66% sensitivity.

  15. Homosexuality in Specific Fields: The Arts, the Military, the Ministry, Prisons, Sports, Teaching and Transsexuals. A Selected Bibliography. Number 13.

    ERIC Educational Resources Information Center

    Miller, Alan V., Comp.

    This bibliography represents the third in a series of three dealing with employment of homosexuals, to be published by the Ontario Ministry of Labour Library. All asterisked titles deal with the employment problems of and discrimination against homosexuals. This bibliography is concerned with homosexuality in the specific fields of the arts, the…

  16. A Method to Teach Age-Specific Demography with Field Grown Rapid Cycling "Brassica rapa" (Wisconsin Fast Plants)

    ERIC Educational Resources Information Center

    Kelly, Martin G.; Terrana, Sebastian

    2004-01-01

    In this paper, we demonstrate that rapid cycling "Brassica rapa" (Wisconsin Fast Plants) can be used in inquiry-based, student ecological fieldwork. We are the first to describe age-specific survival for field-grown Fast Plants and identify life history traits associated with individual survival. This experiment can be adapted by educators as a…

  17. Homosexuality in Specific Fields: The Arts, the Military, the Ministry, Prisons, Sports, Teaching and Transsexuals. A Selected Bibliography. Number 13.

    ERIC Educational Resources Information Center

    Miller, Alan V., Comp.

    This bibliography represents the third in a series of three dealing with employment of homosexuals, to be published by the Ontario Ministry of Labour Library. All asterisked titles deal with the employment problems of and discrimination against homosexuals. This bibliography is concerned with homosexuality in the specific fields of the arts, the…

  18. Low temperature specific heat of CeRu{sub 2}Si{sub 2} at the field induced metamagnetic instability

    SciTech Connect

    Heuser, K.; Scheidt, E.W.; Schreiner, T.; Fisk, Z.; Stewart, G.R.

    2000-02-01

    The authors report specific heat measurements in a broad temperature range between 0.06 and 20 K on single crystalline CeRu{sub 2}Si{sub 2} in magnetic fields applied parallel to the c-direction around the critical field B{sub M}, where the metamagnetic transition from the itinerant to the localized state takes place. In the critical field B{sub M} {parallel} c = 7.8 T a distinct deviation from the usual Fermi-liquid behavior is found down to the lowest temperature. below 1.8 K C/T varies as (1{minus}aT), while for 1.8K < T < 20 K a power law T{sup {lambda}{minus}1} with {lambda} = 0.66 is found. Small deviations from the critical magnetic field leads to the recovery of a Fermi-liquid ground state. The observed behavior of the specific heat at the field induced magnetic instability is discussed in the context of a non-Fermi-liquid state and compared with those for the field-induced nFl CeCu{sub 6{minus}x}Ag{sub x} and the recent observation of nFl behavior at B{sub M} in UPt{sub 3}.

  19. Knowledge About Sounds—Context-Specific Meaning Differently Activates Cortical Hemispheres, Auditory Cortical Fields, and Layers in House Mice

    PubMed Central

    Geissler, Diana B.; Schmidt, H. Sabine; Ehret, Günter

    2016-01-01

    Activation of the auditory cortex (AC) by a given sound pattern is plastic, depending, in largely unknown ways, on the physiological state and the behavioral context of the receiving animal and on the receiver's experience with the sounds. Such plasticity can be inferred when house mouse mothers respond maternally to pup ultrasounds right after parturition and naïve females have to learn to respond. Here we use c-FOS immunocytochemistry to quantify highly activated neurons in the AC fields and layers of seven groups of mothers and naïve females who have different knowledge about and are differently motivated to respond to acoustic models of pup ultrasounds of different behavioral significance. Profiles of FOS-positive cells in the AC primary fields (AI, AAF), the ultrasonic field (UF), the secondary field (AII), and the dorsoposterior field (DP) suggest that activation reflects in AI, AAF, and UF the integration of sound properties with animal state-dependent factors, in the higher-order field AII the news value of a given sound in the behavioral context, and in the higher-order field DP the level of maternal motivation and, by left-hemisphere activation advantage, the recognition of the meaning of sounds in the given context. Anesthesia reduced activation in all fields, especially in cortical layers 2/3. Thus, plasticity in the AC is field-specific preparing different output of AC fields in the process of perception, recognition and responding to communication sounds. Further, the activation profiles of the auditory cortical fields suggest the differentiation between brains hormonally primed to know (mothers) and brains which acquired knowledge via implicit learning (naïve females). In this way, auditory cortical activation discriminates between instinctive (mothers) and learned (naïve females) cognition. PMID:27013959

  20. Knowledge About Sounds-Context-Specific Meaning Differently Activates Cortical Hemispheres, Auditory Cortical Fields, and Layers in House Mice.

    PubMed

    Geissler, Diana B; Schmidt, H Sabine; Ehret, Günter

    2016-01-01

    Activation of the auditory cortex (AC) by a given sound pattern is plastic, depending, in largely unknown ways, on the physiological state and the behavioral context of the receiving animal and on the receiver's experience with the sounds. Such plasticity can be inferred when house mouse mothers respond maternally to pup ultrasounds right after parturition and naïve females have to learn to respond. Here we use c-FOS immunocytochemistry to quantify highly activated neurons in the AC fields and layers of seven groups of mothers and naïve females who have different knowledge about and are differently motivated to respond to acoustic models of pup ultrasounds of different behavioral significance. Profiles of FOS-positive cells in the AC primary fields (AI, AAF), the ultrasonic field (UF), the secondary field (AII), and the dorsoposterior field (DP) suggest that activation reflects in AI, AAF, and UF the integration of sound properties with animal state-dependent factors, in the higher-order field AII the news value of a given sound in the behavioral context, and in the higher-order field DP the level of maternal motivation and, by left-hemisphere activation advantage, the recognition of the meaning of sounds in the given context. Anesthesia reduced activation in all fields, especially in cortical layers 2/3. Thus, plasticity in the AC is field-specific preparing different output of AC fields in the process of perception, recognition and responding to communication sounds. Further, the activation profiles of the auditory cortical fields suggest the differentiation between brains hormonally primed to know (mothers) and brains which acquired knowledge via implicit learning (naïve females). In this way, auditory cortical activation discriminates between instinctive (mothers) and learned (naïve females) cognition.

  1. Single shot trajectory design for region-specific imaging using linear and nonlinear magnetic encoding fields.

    PubMed

    Layton, Kelvin J; Gallichan, Daniel; Testud, Frederik; Cocosco, Chris A; Welz, Anna M; Barmet, Christoph; Pruessmann, Klaas P; Hennig, Jürgen; Zaitsev, Maxim

    2013-09-01

    It has recently been demonstrated that nonlinear encoding fields result in a spatially varying resolution. This work develops an automated procedure to design single-shot trajectories that create a local resolution improvement in a region of interest. The technique is based on the design of optimized local k-space trajectories and can be applied to arbitrary hardware configurations that employ any number of linear and nonlinear encoding fields. The trajectories designed in this work are tested with the currently available hardware setup consisting of three standard linear gradients and two quadrupolar encoding fields generated from a custom-built gradient insert. A field camera is used to measure the actual encoding trajectories up to third-order terms, enabling accurate reconstructions of these demanding single-shot trajectories, although the eddy current and concomitant field terms of the gradient insert have not been completely characterized. The local resolution improvement is demonstrated in phantom and in vivo experiments. Copyright © 2012 Wiley Periodicals, Inc.

  2. SU-C-304-07: Are Small Field Detector Correction Factors Strongly Dependent On Machine-Specific Characteristics?

    SciTech Connect

    Mathew, D; Tanny, S; Parsai, E; Sperling, N

    2015-06-15

    Purpose: The current small field dosimetry formalism utilizes quality correction factors to compensate for the difference in detector response relative to dose deposited in water. The correction factors are defined on a machine-specific basis for each beam quality and detector combination. Some research has suggested that the correction factors may only be weakly dependent on machine-to-machine variations, allowing for determinations of class-specific correction factors for various accelerator models. This research examines the differences in small field correction factors for three detectors across two Varian Truebeam accelerators to determine the correction factor dependence on machine-specific characteristics. Methods: Output factors were measured on two Varian Truebeam accelerators for equivalently tuned 6 MV and 6 FFF beams. Measurements were obtained using a commercial plastic scintillation detector (PSD), two ion chambers, and a diode detector. Measurements were made at a depth of 10 cm with an SSD of 100 cm for jaw-defined field sizes ranging from 3×3 cm{sup 2} to 0.6×0.6 cm{sup 2}, normalized to values at 5×5cm{sup 2}. Correction factors for each field on each machine were calculated as the ratio of the detector response to the PSD response. Percent change of correction factors for the chambers are presented relative to the primary machine. Results: The Exradin A26 demonstrates a difference of 9% for 6×6mm{sup 2} fields in both the 6FFF and 6MV beams. The A16 chamber demonstrates a 5%, and 3% difference in 6FFF and 6MV fields at the same field size respectively. The Edge diode exhibits less than 1.5% difference across both evaluated energies. Field sizes larger than 1.4×1.4cm2 demonstrated less than 1% difference for all detectors. Conclusion: Preliminary results suggest that class-specific correction may not be appropriate for micro-ionization chamber. For diode systems, the correction factor was substantially similar and may be useful for class-specific

  3. Electronic structure of UN based on specific heat and field-induced transitions up to 65 T

    NASA Astrophysics Data System (ADS)

    Troć, R.; Samsel-Czekała, M.; Pikul, A.; Andreev, A. V.; Gorbunov, D. I.; Skourski, Y.; Sznajd, J.

    2016-12-01

    The 5 f electrons of uranium in the uranium mononitride (UN) compound are described in the literature as either localized or fully itinerant. Motivated by these contradictory statements, we studied low-temperature specific heat and high-field magnetization of single-crystalline UN in magnetic fields up to 9 and 65 T, respectively. Our detailed analysis of the magnetic contribution to the specific heat of UN revealed that its real ground state is complex and the 5 f electrons seem to have a dual nature; i.e., they possess simultaneously local and itinerant characters in two substates. High-field experiments allowed us to construct a tentative magnetic phase diagram of UN with a metamagnetic transition from antiferromagnetism to ferrimagnetism at a magnetic field as high as 58 T at 2 K. Such a field only enables a reversal of 1 of the 12 antiferromagnetically coupled ferromagnetic layers in the direction of the magnetic field. Any further steplike transitions require application of ever higher magnetic fields, which is beyond the experimental possibilities. We show that the magnetic phase diagram can be successfully reproduced considering a layer model of the Ising spins. That model allows rough estimation of a phase transition into fully induced ferromagnetism at a field as high as about 258 T. It gives rise to a giant coupling between ferromagnetically ordered layers in UN. The obtained characteristics are presented, together with the results of recent x-ray photoemission spectroscopy and transport property measurements. They are analyzed and compared with a number of earlier experiments and band structure calculations that were performed for this compound and are widely described in the literature. We show that different experiments probe different substates of the uranium 5 f electrons in UN (itinerant or localized), which supports our hypothesis on their dual nature.

  4. Effects of Site-specific Application of Aldicarb on Cotton in a Meloidogyne incognita-infested Field

    PubMed Central

    Wrather, J. A.; Stevens, W. E.; Kirkpatrick, T. L.; Kitchen, N. R.

    2002-01-01

    Cotton farmers in Missouri commonly apply a single rate of aldicarb throughout the field at planting to protect their crop from Meloidogyne incognita, even though these nematodes are spatially aggregated. Our purpose was to determine the effect of site-specific application of aldicarb on cotton production in a field infested with these nematodes in 1997 and 1998. Cotton yields were collected from sites not treated with aldicarb (control), sites receiving aldicarb at the standard recommended rate of 0.58 kg a.i./ha, and sites receiving specific aldicarb rates based on the soil population densities of second-stage infective juveniles of root-knot nematode. Yields for the standard rate and site-specific rate treatments were similar and greater (P ≤ 0.05) than the control treatment. Less aldicarb was used for the site-specific than the uniform-rate treatment each year—46% less in 1997 and 61% less in 1998. Costs associated with the site-specific treatment were very high compared with the uniform-rate treatment due to a greater number of soil samples analyzed for nematodes. Site-specific application of aldicarb for root-knot nematode management in cotton may pose fewer environmental risks than the uniform-rate application of aldicarb. PMID:19265917

  5. Variable rate application of nematicides on cotton fields: A promising site-specific management strategy.

    USDA-ARS?s Scientific Manuscript database

    Field tests were conducted to determine if differences in response to nematicide application (i.e., root-knot nematode (RKN) population levels, cotton yield, and profitability) occurred among RKN management zones (MZ). The MZ were delineated using variables related to soil texture, including appare...

  6. Analyzing Student Performance in Specific Subject Area Indicators on the ETS Major Field Test in Business

    ERIC Educational Resources Information Center

    Settlage, Daniel Murray; Wollscheid, Jim R.

    2015-01-01

    The Major Field Test is a commonly used assessment instrument, but little emphasis has been put on analyzing student-level subject area indicator scores. The Educational Testing Service recently made these data available to institutions, and it is analyzed here. This analysis builds on previous work by incorporating demographic and programmatic…

  7. Generality with Specificity: The Dynamic Field Theory Generalizes across Tasks and Time Scales

    ERIC Educational Resources Information Center

    Simmering, Vanessa R.; Spencer, John P.

    2008-01-01

    A central goal in cognitive and developmental science is to develop models of behavior that can generalize across both tasks and development while maintaining a commitment to detailed behavioral prediction. This paper presents tests of one such model, the Dynamic Field Theory (DFT). The DFT was originally proposed to capture delay-dependent biases…

  8. Rehabilitation of Reading and Visual Exploration in Visual Field Disorders: Transfer or Specificity?

    ERIC Educational Resources Information Center

    Schuett, Susanne; Heywood, Charles A.; Kentridge, Robert W.; Dauner, Ruth; Zihl, Josef

    2012-01-01

    Reading and visual exploration impairments in unilateral homonymous visual field disorders are frequent and disabling consequences of acquired brain injury. Compensatory therapies have been developed, which allow patients to regain sufficient reading and visual exploration performance through systematic oculomotor training. However, it is still…

  9. Rehabilitation of Reading and Visual Exploration in Visual Field Disorders: Transfer or Specificity?

    ERIC Educational Resources Information Center

    Schuett, Susanne; Heywood, Charles A.; Kentridge, Robert W.; Dauner, Ruth; Zihl, Josef

    2012-01-01

    Reading and visual exploration impairments in unilateral homonymous visual field disorders are frequent and disabling consequences of acquired brain injury. Compensatory therapies have been developed, which allow patients to regain sufficient reading and visual exploration performance through systematic oculomotor training. However, it is still…

  10. Identification of Strain-Specific Sequences That Distinguish a Mycoplasma gallisepticum Vaccine Strain from Field Isolates

    PubMed Central

    Ricketts, Camir; Pickler, Larissa; Maurer, John; Ayyampalayam, Saravanaraj; García, Maricarmen

    2016-01-01

    ABSTRACT Despite attempts to control avian mycoplasmosis through management, vaccination, and surveillance, Mycoplasma gallisepticum continues to cause significant morbidity, mortality, and economic losses in poultry production. Live attenuated vaccines are commonly used in the poultry industry to control avian mycoplasmosis; unfortunately, some vaccines may revert to virulence and vaccine strains are generally difficult to distinguish from natural field isolates. In order to identify genome differences among vaccine revertants, vaccine strains, and field isolates, whole-genome sequencing of the M. gallisepticum vaccine strain ts-11 and several “ts-11-like” strains isolated from commercial flocks was performed using Illumina and 454 pyrosequencing and the sequenced genomes compared to the M. gallisepticum Rlow reference genome. The collective contigs for each strain were annotated using the fully annotated Mycoplasma reference genome. The analysis revealed genetic differences among vlhA alleles, as well as among genes annotated as coding for a cell wall surface anchor protein (mg0377) and a hypothetical protein gene, mg0359, unique to M. gallisepticum ts-11 vaccine strain. PCR protocols were designed to target 5 sequences unique to the M. gallisepticum ts-11 strain: vlhA3.04a, vlhA3.04b, vlhA3.05, mg0377, and mg0359. All ts-11 isolates were positive for the five gene alleles tested by PCR; however, 5 to 36% of field isolates were also positive for at least one of the alleles tested. A combination of PCR tests for vlhA3.04a, vlhA3.05, and mg0359 was able to distinguish the M. gallisepticum ts-11 vaccine strain from field isolates. This method will further supplement current approaches to quickly distinguish M. gallisepticum vaccine strains from field isolates. PMID:27847370

  11. Magneto-electric Nanoparticles to Enable Field-controlled High-Specificity Drug Delivery to Eradicate Ovarian Cancer Cells

    NASA Astrophysics Data System (ADS)

    Guduru, Rakesh; Liang, Ping; Runowicz, Carolyn; Nair, Madhavan; Atluri, Venkata; Khizroev, Sakhrat

    2013-10-01

    The nanotechnology capable of high-specificity targeted delivery of anti-neoplastic drugs would be a significant breakthrough in Cancer in general and Ovarian Cancer in particular. We addressed this challenge through a new physical concept that exploited (i) the difference in the membrane electric properties between the tumor and healthy cells and (ii) the capability of magneto-electric nanoparticles (MENs) to serve as nanosized converters of remote magnetic field energy into the MENs' intrinsic electric field energy. This capability allows to remotely control the membrane electric fields and consequently trigger high-specificity drug uptake through creation of localized nano-electroporation sites. In in-vitro studies on human ovarian carcinoma cell (SKOV-3) and healthy cell (HOMEC) lines, we applied a 30-Oe d.c. field to trigger high-specificity uptake of paclitaxel loaded on 30-nm CoFe2O4@BaTiO3 MENs. The drug penetrated through the membrane and completely eradicated the tumor within 24 hours without affecting the normal cells.

  12. Clearing the waters: Evaluating the need for site-specific field fluorescence corrections based on turbidity measurements

    USGS Publications Warehouse

    Saraceno, John F.; Shanley, James B.; Downing, Bryan D.; Pellerin, Brian A.

    2017-01-01

    In situ fluorescent dissolved organic matter (fDOM) measurements have gained increasing popularity as a proxy for dissolved organic carbon (DOC) concentrations in streams. One challenge to accurate fDOM measurements in many streams is light attenuation due to suspended particles. Downing et al. (2012) evaluated the need for corrections to compensate for particle interference on fDOM measurements using a single sediment standard in a laboratory study. The application of those results to a large river improved unfiltered field fDOM accuracy. We tested the same correction equation in a headwater tropical stream and found that it overcompensated fDOM when turbidity exceeded ∼300 formazin nephelometric units (FNU). Therefore, we developed a site-specific, field-based fDOM correction equation through paired in situ fDOM measurements of filtered and unfiltered streamwater. The site-specific correction increased fDOM accuracy up to a turbidity as high as 700 FNU, the maximum observed in this study. The difference in performance between the laboratory-based correction equation of Downing et al. (2012) and our site-specific, field-based correction equation likely arises from differences in particle size distribution between the sediment standard used in the lab (silt) and that observed in our study (fine to medium sand), particularly during high flows. Therefore, a particle interference correction equation based on a single sediment type may not be ideal when field sediment size is significantly different. Given that field fDOM corrections for particle interference under turbid conditions are a critical component in generating accurate DOC estimates, we describe a way to develop site-specific corrections.

  13. Residue-specific force field based on protein coil library. RSFF2: modification of AMBER ff99SB.

    PubMed

    Zhou, Chen-Yang; Jiang, Fan; Wu, Yun-Dong

    2015-01-22

    Recently, we developed a residue-specific force field (RSFF1) based on conformational free-energy distributions of the 20 amino acid residues from a protein coil library. Most parameters in RSFF1 were adopted from the OPLS-AA/L force field, but some van der Waals and torsional parameters that effectively affect local conformational preferences were introduced specifically for individual residues to fit the coil library distributions. Here a similar strategy has been applied to modify the Amber ff99SB force field, and a new force field named RSFF2 is developed. It can successfully fold α-helical structures such as polyalanine peptides, Trp-cage miniprotein, and villin headpiece subdomain and β-sheet structures such as Trpzip-2, GB1 β-hairpins, and the WW domain, simultaneously. The properties of various popular force fields in balancing between α-helix and β-sheet are analyzed based on their descriptions of local conformational features of various residues, and the analysis reveals the importance of accurate local free-energy distributions. Unlike the RSFF1, which overestimates the stability of both α-helix and β-sheet, RSFF2 gives melting curves of α-helical peptides and Trp-cage in good agreement with experimental data. Fitting to the two-state model, RSFF2 gives folding enthalpies and entropies in reasonably good agreement with available experimental results.

  14. Influence of the electric field on supramolecular structure and properties of amyloid-specific reagent Congo red.

    PubMed

    Spólnik, Paweł; Król, Marcin; Stopa, Barbara; Konieczny, Leszek; Piekarska, Barbara; Rybarska, Janina; Zemanek, Grzegorz; Jagusiak, Anna; Piwowar, Piotr; Szoniec, Grzegorz; Roterman, Irena

    2011-10-01

    Among specific amyloid ligands, Congo red and its analogues are often considered potential therapeutic compounds. However, the results of the studies so far have not been univocal because the properties of this dye, derived mostly from its supramolecular nature, are still poorly understood. The supramolecular structure of Congo red, formed by π-π stacking of dye molecules, is susceptible to the influence of the electric field, which may significantly facilitate electron delocalization. Consequently, the electric field may generate altered physico-chemical properties of the dye. Enhanced electron delocalization, induced by the electric field, alters the total charge of Congo red, making the dye more acidic (negatively charged). This is a consequence of withdrawing electrons from polar substituents of aromatic rings-sulfonic and amino groups-thus increasing their tendency to dissociate protons. The electric field-induced charge alteration observed in electrophoresis depends on dye concentration. This concentration-dependent charge alteration effect disappears when the supramolecular structure disintegrates in DMSO. Dipoles formed from supramolecular fibrillar species in the electric field become ordered in the solution, introducing the modified arrangement to liquid crystalline phase. Experimental results and theoretical studies provide evidence confirming predictions that the supramolecular character of Congo red is the main reason for its specific properties and reactivity.

  15. Crystal-field study of magnetization and specific heat properties of frustrated pyrochlore Pr2Zr2O7

    NASA Astrophysics Data System (ADS)

    Alam, J.; Jana, Y. M.; Biswas, A. Ali

    2016-10-01

    The experimental results of temperature dependent dc magnetic susceptibility, field dependent isothermal magnetization, magnetic specific heat and entropy of the pyrochlore Pr2Zr2O7 are simulated and analyzed using appropriate D3d crystal-field (CF) and anisotropic molecular field tensors at Pr-sites in the self-consistent mean-field approach involving four magnetically non-equivalent rare-earth spins on the tetrahedral unit of the pyrochlore structure. CF level pattern and wave-functions of the ground 3H4 multiplet of the Pr3+ ions are obtained considering intermediate coupling between different Russell-Saunders terms of the 4f2 electronic configurations of Pr-ion and J-mixing effects. CF analysis shows that the CF ground-state of the Pr3+ ion in Pr2Zr2O7 is a well-isolated doublet, with significant admixtures of terms coming from |MJ=±4> and |MJ=±1>, and the Pr-spins are effectively Ising-like along the local <111> axes. Magnetic specific heat in zero-field is simulated by considering a temperature dependence of the exchange splitting of the ground doublet.

  16. Effects of 60-Hz electric fields on specific humoral and cellular components of the immune system

    SciTech Connect

    Morris, J.E.; Phillips, R.D.

    1982-01-01

    Humoral and cellular functions of the immune system of Swiss-Webster mice were evaluated after exposure to 60-Hz electric fields at 100 kV/m. No significant differences were observed in primary antibody response to keyhole limpet hemocyanin (precipitating antibody levels) between exposed (30 or 60 days) and control mice, nor were there significant changes in mitogen-stimulation response of spleen cells from mice similarly exposed for 90 or 150 days when compared to sham-exposed animals.

  17. Solving the Orientation Specific Constraints in Transcranial Magnetic Stimulation by Rotating Fields

    PubMed Central

    Neef, Nicole E.; Agudelo-Toro, Andres; Rakhmilevitch, David; Paulus, Walter; Moses, Elisha

    2014-01-01

    Transcranial Magnetic Stimulation (TMS) is a promising technology for both neurology and psychiatry. Positive treatment outcome has been reported, for instance in double blind, multi-center studies on depression. Nonetheless, the application of TMS towards studying and treating brain disorders is still limited by inter-subject variability and lack of model systems accessible to TMS. The latter are required to obtain a deeper understanding of the biophysical foundations of TMS so that the stimulus protocol can be optimized for maximal brain response, while inter-subject variability hinders precise and reliable delivery of stimuli across subjects. Recent studies showed that both of these limitations are in part due to the angular sensitivity of TMS. Thus, a technique that would eradicate the need for precise angular orientation of the coil would improve both the inter-subject reliability of TMS and its effectiveness in model systems. We show here how rotation of the stimulating field relieves the angular sensitivity of TMS and provides improvements in both issues. Field rotation is attained by superposing the fields of two coils positioned orthogonal to each other and operated with a relative phase shift in time. Rotating field TMS (rfTMS) efficiently stimulates both cultured hippocampal networks and rat motor cortex, two neuronal systems that are notoriously difficult to excite magnetically. This opens the possibility of pharmacological and invasive TMS experiments in these model systems. Application of rfTMS to human subjects overcomes the orientation dependence of standard TMS. Thus, rfTMS yields optimal targeting of brain regions where correct orientation cannot be determined (e.g., via motor feedback) and will enable stimulation in brain regions where a preferred axonal orientation does not exist. PMID:24505266

  18. Site-specific risk factors for ray blight in Tasmanian pyrethrum fields

    USDA-ARS?s Scientific Manuscript database

    Ray blight of pyrethrum, caused by Phoma ligulicola var. inoxydablis can cause significant reductions in crop growth and pyrethrin yield. Weather and site-specific disease risk factors for ray blight have not been identified or quantified in terms of relative risk, which has limited the efficiency ...

  19. Site-specific irrigation of peanuts on a Coastal Plain field

    USDA-ARS?s Scientific Manuscript database

    Irrigator-Pro is an expert system that prescribes irrigation for corn (Zea mays L.), cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea). We conducted an experiment in 2007 to evaluate Irrigator-Pro as a tool for variable rate irrigation of peanut using a site-specific center pivot irrigati...

  20. Specificity in Interest Measurement: Basic Interest Scales and Major Field of Study

    ERIC Educational Resources Information Center

    Ralston, Chistopher A.; Borgen, Fred H.; Rottinghaus, Patrick J.; Donnay, David A. C.

    2004-01-01

    The Basic Interest Scales (BISs) of the Strong Interest Inventory (SII; Harmon, Hansen, Borgen, & Hammer, 1994) have a 35-year history. The BISs are the specific content scales of the SII, as opposed to the SII general content scales, the General Occupational Themes (GOTs), which measure the six Holland (1997) RIASEC themes. Using 17,074…

  1. The specific host plant DNA detection suggests a potential migration of Apolygus lucorum from cotton to mungbean fields.

    PubMed

    Wang, Qian; Bao, Wei-Fang; Yang, Fan; Xu, Bin; Yang, Yi-Zhong

    2017-01-01

    The polyphagous mirid bug Apolygus lucorum (Heteroptera: Miridae) has more than 200 species of host plants and is an insect pest of important agricultural crops, including cotton (Gossypium hirsutum) and mungbean (Vigna radiata). Previous field trials have shown that A. lucorum adults prefer mungbean to cotton plants, indicating the considerable potential of mungbean as a trap crop in cotton fields. However, direct evidence supporting the migration of A. lucorum adults from cotton to mungbean is lacking. We developed a DNA-based polymerase chain reaction (PCR) approach to reveal the movement of A. lucorum between neighboring mungbean and cotton fields. Two pairs of PCR primers specific to cotton or mungbean were designed to target the trnL-trnF region of chloroplast DNA. Significant differences in the detectability half-life (DS50) were observed between these two host plants, and the mean for cotton (8.26 h) was approximately two times longer than that of mungbean (4.38 h), requiring weighted mean calculations to compare the detectability of plant DNA in the guts of field-collected bugs. In field trials, cotton DNA was detected in the guts of the adult A. lucorum individuals collected in mungbean plots, and the cotton DNA detection rate decreased successively from 5 to 15 m away from the mungbean-cotton midline. In addition to the specific detection of cotton- and mungbean-fed bugs, both cotton and mungbean DNA were simultaneously detected within the guts of single individuals caught from mungbean fields. This study successfully established a tool for molecular gut-content analyses and clearly demonstrated the movement of A. lucorum adults from cotton to neighboring mungbean fields, providing new insights into understanding the feeding characteristics and landscape-level ecology of A. lucorum under natural conditions.

  2. Suppression of experimental allergic encephalomyelitis is specific to the frequency and intensity of nocturnally applied, intermittent magnetic fields in rats.

    PubMed

    Cook, L L; Persinger, M A

    2000-10-13

    Female Lewis rats (n=72) were inoculated with an emulsion of spinal cord and complete Freund's adjuvant. They were then exposed for approximately 6 min every hour between midnight and 08:00 h for 2 weeks to either 7 or 40 Hz amplitude-modulated magnetic fields whose temporal pattern was designed to simulate a (geomagnetic) storm sudden commencement. The peak strengths of the fields averaged between either 30-50 nT (low intensity) or 500 nT (high intensity). Rats exposed to the 7 Hz, low intensity magnetic fields displayed significantly less severe overt signs of experimental allergic encephalomyelitis than rats exposed to either of the two intensities of the 40 Hz fields, the high intensity 7 Hz field, or the reference (<10 nT) condition. The latter groups did not differ significantly from each other. Predicted severity based upon the numbers of foci of infiltrations of lymphocytes within the brains of the rats also demonstrated the ameliorating effects of the low intensity, 7 Hz exposures. These results suggest very specific characteristics of complex, weak magnetic fields within the sleeping environment could affect the symptoms of autoimmunity.

  3. Performance of soccer players on tests of field dependence/independence and soccer-specific decision-making tests.

    PubMed

    McMorris, T

    1997-10-01

    The purpose of this study was to examine the relationship of the performance of male amateur soccer players on tests of field dependence/independence and soccer-specific decision-making tests. The relationships between the participants' (N = 14) accuracy, and speed of decision, on simple and complex soccer decision-making tests; scores on Parts B or C of the Group Embedded Figures Test under normal conditions: scores on Parts B or C of the Group Embedded Figures Test when timed; and time taken to complete the timed condition of the Group Embedded Figures Test were examined. There were no significant correlations between performance on the soccer specific tests and the tests of field dependence/independence.

  4. Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head

    PubMed Central

    Fakhri, Yadolah; Alinejad, Azim; Keramati, Hassan; Bay, Abotaleb; Avazpour, Moayed; Zandsalimi, Yahya; Moradi, Bigard; Amirhajeloo, Leila Rasouli; Mirzaei, Maryam

    2016-01-01

    The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m and 2.23±0.39 v/m, respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23% and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart mobile phones at the frequencies of 900 and 1800 MHz was significantly higher than Samsung (p value <0.05). Hence, we can say that in a fixed period, health risks of Nokia smart phones is higher than Samsung smart mobile phone. PMID:27157169

  5. Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head.

    PubMed

    Fakhri, Yadolah; Alinejad, Azim; Keramati, Hassan; Bay, Abotaleb; Avazpour, Moayed; Zandsalimi, Yahya; Moradi, Bigard; Rasouli Amirhajeloo, Leila; Mirzaei, Maryam

    2016-09-01

    The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m  and 2.23±0.39 v/m , respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23 %and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart  mobile phones at the frequencies of 900 and 1800 MHz  was significantly higher than Samsung (p value <0.05). Hence, we can say that in a fixed period, health risks of Nokia smart phones is higher than Samsung smart mobile phone.

  6. Field Trials Reveal Ecotype-Specific Responses to Mycorrhizal Inoculation in Rice

    PubMed Central

    Diedhiou, Abdala Gamby; Mbaye, Fatou Kine; Mbodj, Daouda; Faye, Mathieu Ndigue; Pignoly, Sarah; Ndoye, Ibrahima; Djaman, Koffi; Gaye, Souleymane; Kane, Aboubacry; Laplaze, Laurent; Manneh, Baboucarr; Champion, Antony

    2016-01-01

    The overuse of agricultural chemicals such as fertilizer and pesticides aimed at increasing crop yield results in environmental damage, particularly in the Sahelian zone where soils are fragile. Crop inoculation with beneficial soil microbes appears as a good alternative for reducing agricultural chemical needs, especially for small farmers. This, however, requires selecting optimal combinations of crop varieties and beneficial microbes tested in field conditions. In this study, we investigated the response of rice plants to inoculation with arbuscular mycorrhizal fungi (AMF) and plant growth promoting bacteria (PGPB) under screenhouse and field conditions in two consecutive seasons in Senegal. Evaluation of single and mixed inoculations with AMF and PGPB was conducted on rice (Oryza sativa) variety Sahel 202, on sterile soil under screenhouse conditions. We observed that inoculated plants, especially plants treated with AMF, grew taller, matured earlier and had higher grain yield than the non-inoculated plants. Mixed inoculation trials with two AMF strains were then conducted under irrigated field conditions with four O. sativa varieties, two O. glaberrima varieties and two interspecific NERICA varieties, belonging to 3 ecotypes (upland, irrigated, and rainfed lowland). We observed that the upland varieties had the best responses to inoculation, especially with regards to grain yield, harvest index and spikelet fertility. These results show the potential of using AMF to improve rice production with less chemical fertilizers and present new opportunities for the genetic improvement in rice to transfer the ability of forming beneficial rice-microbe associations into high yielding varieties in order to increase further rice yield potentials. PMID:27907023

  7. Field Trials Reveal Ecotype-Specific Responses to Mycorrhizal Inoculation in Rice.

    PubMed

    Diedhiou, Abdala Gamby; Mbaye, Fatou Kine; Mbodj, Daouda; Faye, Mathieu Ndigue; Pignoly, Sarah; Ndoye, Ibrahima; Djaman, Koffi; Gaye, Souleymane; Kane, Aboubacry; Laplaze, Laurent; Manneh, Baboucarr; Champion, Antony

    2016-01-01

    The overuse of agricultural chemicals such as fertilizer and pesticides aimed at increasing crop yield results in environmental damage, particularly in the Sahelian zone where soils are fragile. Crop inoculation with beneficial soil microbes appears as a good alternative for reducing agricultural chemical needs, especially for small farmers. This, however, requires selecting optimal combinations of crop varieties and beneficial microbes tested in field conditions. In this study, we investigated the response of rice plants to inoculation with arbuscular mycorrhizal fungi (AMF) and plant growth promoting bacteria (PGPB) under screenhouse and field conditions in two consecutive seasons in Senegal. Evaluation of single and mixed inoculations with AMF and PGPB was conducted on rice (Oryza sativa) variety Sahel 202, on sterile soil under screenhouse conditions. We observed that inoculated plants, especially plants treated with AMF, grew taller, matured earlier and had higher grain yield than the non-inoculated plants. Mixed inoculation trials with two AMF strains were then conducted under irrigated field conditions with four O. sativa varieties, two O. glaberrima varieties and two interspecific NERICA varieties, belonging to 3 ecotypes (upland, irrigated, and rainfed lowland). We observed that the upland varieties had the best responses to inoculation, especially with regards to grain yield, harvest index and spikelet fertility. These results show the potential of using AMF to improve rice production with less chemical fertilizers and present new opportunities for the genetic improvement in rice to transfer the ability of forming beneficial rice-microbe associations into high yielding varieties in order to increase further rice yield potentials.

  8. Specific features of motion of molten zones in the field of silicon structural inhomogeneity

    NASA Astrophysics Data System (ADS)

    Skvortsov, A. A.; Zuev, S. M.; Koryachko, M. V.; Voloshinov, E. B.

    2017-08-01

    The formation and dynamics of molten Al-Si inclusions in silicon at temperatures of 1123-1273 K in the dislocation-density gradient field are investigated. It is established that the molten inclusion moves as a whole in accordance with the melting-crystallization mechanism: dissolution is observed at the front boundary in the region with a higher dislocation concentration and crystallization and on the back surface in the region with a lower one. The migration rates and activation energies are experimentally determined. It is demonstrated that the inclusion migration is limited by the melting-crystallization processes at the interfaces between the melt and matrix.

  9. Cohort study on the effects of everyday life radio frequency electromagnetic field exposure on non-specific symptoms and tinnitus.

    PubMed

    Frei, Patrizia; Mohler, Evelyn; Braun-Fahrländer, Charlotte; Fröhlich, Jürg; Neubauer, Georg; Röösli, Martin

    2012-01-01

    There is public concern regarding potential health effects of radio frequency electromagnetic fields (RF-EMF) exposure, as produced by mobile phones or broadcast transmitters. The objective of this study was to investigate the association between RF-EMF exposure and non-specific symptoms and tinnitus in a prospective cohort study. In 2008, 1375 randomly selected participants from Basel, Switzerland, were enrolled in a questionnaire survey with follow-up after one year (participation rate 82%). A score for somatic complaints (von Zerssen list) and headache (HIT-6) was assessed. Far-field environmental RF-EMF exposure was predicted using a validated prediction model. Regarding near-field exposure, self-reported mobile and cordless phone use as well as mobile phone operator data were collected. In multivariate regression models, we investigated whether exposure at baseline (cohort analysis) or changes in exposure between baseline and follow-up (change analysis) were related to changes in health scores. For participants in the top decile of environmental far-field RF-EMF exposure at baseline, in comparison to participants exposed below the median value, the change in the von Zerssen- and HIT-6-scores between baseline and follow-up was -0.12 (95%-CI: -1.79 to 1.56) and -0.37 (95%-CI: -1.80 to 1.07) units, respectively. Exposure to near-field sources and a change in exposure between baseline and follow-up were not related to non-specific symptoms. Similarly, no association between RF-EMF exposure and tinnitus was observed. In this first cohort study using objective and well-validated RF-EMF exposure measures, we did not observe an association between RF-EMF exposure and non-specific symptoms or tinnitus. Copyright © 2011. Published by Elsevier Ltd.

  10. Specific features of the states of cobalt fluoride in the vicinity of the critical field

    NASA Astrophysics Data System (ADS)

    Medvedovskaya, O. G.; Fedorenko, T. A.; Chepurnykh, G. K.

    2016-12-01

    The state of cobalt fluoride in the vicinity of the critical value H c of a longitudinal magnetic field H, in which the magnetic subsystem of a CoF2 crystal with a strong Dzyaloshinskii interaction is transformed from the antiferromagnetic phase into the canted phase, has been investigated taking into account the increasing number of experimental studies related to the use of cobalt fluoride. It has been found that, despite the unusually high magnetic anisotropy of the crystal, the state of the magnetic subsystem at H = H c is extremely sensitive to a small deviation of the vector H from the C 4 axis. Another feature is that the high sensitivity disappears with an increase or decrease in the magnetic field by only a few thousandths of H c . The results of the investigations performed in this work are applicable to magnetically ordered crystals FeF3 and Cu2OSeO3, which, as well as the CoF2 crystals, are characterized by a strong Dzyaloshinskii interaction and a significant magnetic anisotropy. The revealed anomaly in the reduction of the effective magnetic anisotropy is of interest in connection with numerous attempts to decrease the magnetic anisotropy in crystals with giant magnetostriction, which are necessary for the use as sensors and vibrators.

  11. Residue-specific force field based on the protein coil library. RSFF1: modification of OPLS-AA/L.

    PubMed

    Jiang, Fan; Zhou, Chen-Yang; Wu, Yun-Dong

    2014-06-26

    Traditional protein force fields use one set of parameters for most of the 20 amino acids (AAs), allowing transferability of the parameters. However, a significant shortcoming is the difficulty to fit the Ramachandran plots of all AA residues simultaneously, affecting the accuracy of the force field. In this Feature Article, we report a new strategy for protein force field parametrization. Backbone and side-chain conformational distributions of all 20 AA residues obtained from protein coil library were used as the target data. The dihedral angle (torsion) potentials and some local nonbonded (1-4/1-5/1-6) interactions in OPLS-AA/L force field were modified such that the target data can be excellently reproduced by molecular dynamics simulations of dipeptides (blocked AAs) in explicit water, resulting in a new force field with AA-specific parameters, RSFF1. An efficient free energy decomposition approach was developed to separate the corrections on ϕ and ψ from the two-dimensional Ramachandran plots. RSFF1 is shown to reproduce the experimental NMR (3)J-coupling constants of AA dipeptides better than other force fields. It has a good balance between α-helical and β-sheet secondary structures. It can successfully fold a set of α-helix proteins (Trp-cage and Homeodomain) and β-hairpins (Trpzip-2, GB1 hairpin), which cannot be consistently stabilized by other state-of-the-art force fields. Interestingly, the RSFF1 force field systematically overestimates the melting temperature (and the stability of native state) of these peptides/proteins. It has a potential application in the simulation of protein folding and protein structure refinement.

  12. Prenatal exposures to LTP-patterned magnetic fields: quantitative effects on specific limbic structures and acquisition of contextually conditioned fear.

    PubMed

    Whissell, P D; Tsang, E W; Mulligan, B P; Persinger, M A

    2009-01-01

    Weak (<1 microT) complex magnetic fields (CMFs) may exert their behavioral influences through the hippocampus by resonating by accident or design with intrinsic electrical patterns. Rats were exposed prenatally to one of four intensities of a CMF (either <5 nanoTesla [nT], 10-50 nT, 50-500 nT, or 500-1000 nT) designed to interact with the process of Long-Term Potentiation (LTP) in the hippocampus. Rats then underwent testing in the forced swim, open field, and fear-conditioning procedures. The cell densities of all amygdaloid nuclei, specific hypothalamic structures, and the major regions of the hippocampus were quantified. Results showed that acquisition of conditioned fear was strongly inhibited in animals exposed to LTP-CMFs. Rats exposed to intensities above 10 nT showed decreased cell density in the CA2 fields of the hippocampus; more neurons were present in the CA1 fields of rats exposed to the 10-50 nT intensities compared to all other groups. A decrease in cell density in the medial preoptic nucleus was linearly dependent on field intensity. In the forced-swim test, swimming was decreased in rats that had been exposed to low (10-50 nT) and medium intensity (50-500 nT) LTP-CMFs in a manner consistent with monoamine modulation. In the open field, exposed rats were indistinguishable from controls. These findings support the hypothesis that continuous exposure during prenatal development to CMFs designed to simulate intrinsic LTP within the hippocampus can affect adult behaviors specific to this structure and produce quantitative alterations in neuronal density.

  13. Specificity of probe measurements in diffuse plasmas of dense gases in strong electric fields

    NASA Astrophysics Data System (ADS)

    Akishev, Yu. S.; Medvedev, M. A.; Napartovich, A. P.; Petryakov, A. V.; Trushkin, N. I.; Shafikov, A. G.

    2017-04-01

    The article is devoted to extending the applicability of the probe diagnostics to the range of higher pressures of the plasma-forming gas by taking into account the effect of the probe shadow on the anode. The probe current-voltage characteristic in the diffuse plasma of a dense gas in a strong electric field was measured, and the influence of the probe potential and probe current on the dimensions of the probe shadow on the anode was studied experimentally. The experiments were carried at different currents of a steady-state glow discharge and different velocities of the gas flow through the discharge. The plasma-forming gas was nitrogen at a pressure of P = 100 Torr.

  14. Host specificity of North American Rhabdias spp. (Nematoda: Rhabdiasidae): combining field data and experimental infections with a molecular phylogeny.

    PubMed

    Langford, Gabriel J; Janovy, John

    2013-04-01

    Lungworms of the cosmopolitan genus Rhabdias are among the most common parasites of amphibians and squamate reptiles. The present study used experimental infections, field studies, and a molecular phylogeny to determine the host specificity of 6 Rhabdias spp. that infect snakes and anurans from North America. The molecular phylogeny suggests Rhabdias ranae from Nebraska and Mississippi may represent separate, cryptic species. In addition, the phylogeny strongly supports separate clades for anuran and snake lungworms. Field studies and experimental infections indicate that snake lungworms are generalist snake parasites; however, laboratory experiments also suggest that lizards can be infected under some environmental conditions. Lungworms from anurans were found not to infect salamanders or reptiles, in nature or in the laboratory; anuran lungworm species ranged from strict host specificity, e.g., R. ranae from Nebraska, to relative generalist, e.g., Rhabdias joaquinensis from Nebraska. Overall, host specificity for species of Rhabdias does not provide support for the evolution of progressive specialization over time. For most species of lungworms, host specificity in nature appears to be limited by both ecological and physiological factors, which vary between species and their hosts. Furthermore, some lungworms, e.g., Rhabdias bakeri from Missouri, appear to be tracking host resources instead of host phylogenies, an example of ecological fitting.

  15. An Ab Initio Method for Designing Multi-Target Specific Pharmacophores using Complementary Interaction Field of Aspartic Proteases.

    PubMed

    Kaalia, Rama; Kumar, Amit; Srinivasan, Ashwin; Ghosh, Indira

    2015-06-01

    For past few decades, key objectives of rational drug discovery have been the designing of specific and selective ligands for target proteins. Infectious diseases like malaria are continuously becoming resistant to traditional medicines, which inculcates need for new approaches to design inhibitors for antimalarial targets. A novel method for ab initio designing of multi target specific pharmacophores using the interaction field maps of active sites of multiple proteins has been developed to design 'specificity' pharmacophores for aspartic proteases. The molecular interaction field grid maps of active sites of aspartic proteases (plasmepsin II & IV from Plasmodium falciparum, plasmepsin from Plasmodium vivax, pepsin & cathepsin D from human) are calculated and common pharmacophoric features for favourable binding spots in active sites are extracted in the form of cliques of graphs using inductive logic programming (ILP). The two pharmacophore ensembles are constructed from largest common cliques by imposing size of receptor active site (L) and domain-specific receptor-ligand information (S). The overlap of chemical space between two ensembles and the results of virtual screening of inhibitor database with known activities show that this method can design efficient pharmacophores with no prior ligand information. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Radiofrequency electromagnetic field exposure and non-specific symptoms of ill health: A systematic review

    SciTech Connect

    Roeoesli, Martin

    2008-06-15

    This article is a systematic review of whether everyday exposure to radiofrequency electromagnetic field (RF-EMF) causes symptoms, and whether some individuals are able to detect low-level RF-EMF (below the ICNIRP [International Commission on Non-Ionizing Radiation Protection] guidelines). Peer-reviewed articles published before August 2007 were identified by means of a systematic literature search. Meta-analytic techniques were used to pool the results from studies investigating the ability to discriminate active from sham RF-EMF exposure. RF-EMF discrimination was investigated in seven studies including a total of 182 self-declared electromagnetic hypersensitive (EHS) individuals and 332 non-EHS individuals. The pooled correct field detection rate was 4.2% better than expected by chance (95% CI: -2.1 to 10.5). There was no evidence that EHS individuals could detect presence or absence of RF-EMF better than other persons. There was little evidence that short-term exposure to a mobile phone or base station causes symptoms based on the results of eight randomized trials investigating 194 EHS and 346 non-EHS individuals in a laboratory. Some of the trials provided evidence for the occurrence of nocebo effects. In population based studies an association between symptoms and exposure to RF-EMF in the everyday environment was repeatedly observed. This review showed that the large majority of individuals who claims to be able to detect low level RF-EMF are not able to do so under double-blind conditions. If such individuals exist, they represent a small minority and have not been identified yet. The available observational studies do not allow differentiating between biophysical from EMF and nocebo effects.

  17. On the importance of diffusion and compound-specific mixing for groundwater transport: An investigation from pore to field scale

    NASA Astrophysics Data System (ADS)

    Rolle, Massimo; Chiogna, Gabriele; Hochstetler, David L.; Kitanidis, Peter K.

    2013-10-01

    Mixing processes significantly affect and limit contaminant transport and transformation rates in the subsurface. The correct quantification of mixing in groundwater systems must account for diffusion, local-scale dispersion and the flow variability in heterogeneous flow fields (e.g., flow-focusing in high-conductivity and de-focusing in low-conductivity zones). Recent results of multitracer laboratory experiments revealed the significant effect of compound-specific diffusive properties on the physical displacement of dissolved species across a representative range of groundwater flow velocities. The goal of this study is to investigate the role of diffusion and compound-specific mixing for solute transport across a range of scales including: (i) pore-scale (~ 10- 2 m), (ii) laboratory bench-scale (~ 100 m) and (iii) field-scale (~ 102 m). We investigate both conservative and mixing-controlled reactive transport using pore-scale modeling, flow-through laboratory experiments and simulations, and field-scale numerical modeling of complex heterogeneous hydraulic conductivity fields with statistical properties similar to the ones reported for the extensively investigated Borden aquifer (Ontario, Canada) and Columbus aquifer (Mississippi, USA, also known as MADE site). We consider different steady-state and transient transport scenarios. For the conservative cases we use as a metric of mixing the exponential of the Shannon entropy to quantify solute dilution either in a given volume (dilution index) or in a given solute flux (flux-related dilution index). The decrease in the mass and the mass-flux of the contaminant plumes is evaluated to quantify reactive mixing. The results show that diffusive processes, occurring at the small-scale of a pore channel, strongly affect conservative and reactive solute transport at larger macroscopic scales. The outcomes of our study illustrate the need to consider and properly account for compound-specific diffusion and mixing

  18. Topographically specific functional connectivity between visual field maps in the human brain.

    PubMed

    Heinzle, Jakob; Kahnt, Thorsten; Haynes, John-Dylan

    2011-06-01

    Neural activity in mammalian brains exhibits large spontaneous fluctuations whose structure reveals the intrinsic functional connectivity of the brain on many spatial and temporal scales. Between remote brain regions, spontaneous activity is organized into large-scale functional networks. To date, it has remained unclear whether the intrinsic functional connectivity between brain regions scales down to the fine detail of anatomical connections, for example the fine-grained topographic connectivity structure in visual cortex. Here, we show that fMRI signal fluctuations reveal a detailed retinotopically organized functional connectivity structure between the visual field maps of remote areas of the human visual cortex. The structured coherent fluctuations were even preserved in complete darkness when all visual input was removed. While the topographic connectivity structure was clearly visible in within hemisphere connections, the between hemisphere connectivity structure differs for representations along the vertical and horizontal meridian respectively. These results suggest a tight link between spontaneous neural activity and the fine-grained topographic connectivity pattern of the human brain. Thus, intrinsic functional connectivity reflects the detailed connectivity structure of the cortex at a fine spatial scale. It might thus be a valuable tool to complement anatomical studies of the human connectome, which is one of the keys to understand the functioning of the human brain. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Physiological and metabolic responses of repeated-sprint activities:specific to field-based team sports.

    PubMed

    Spencer, Matt; Bishop, David; Dawson, Brian; Goodman, Carmel

    2005-01-01

    Field-based team sports, such as soccer, rugby and hockey are popular worldwide. There have been many studies that have investigated the physiology of these sports, especially soccer. However, some fitness components of these field-based team sports are poorly understood. In particular, repeated-sprint ability (RSA) is one area that has received relatively little research attention until recent times. Historically, it has been difficult to investigate the nature of RSA, because of the unpredictability of player movements performed during field-based team sports. However, with improvements in technology, time-motion analysis has allowed researchers to document the detailed movement patterns of team-sport athletes. Studies that have published time-motion analysis during competition, in general, have reported the mean distance and duration of sprints during field-based team sports to be between 10-20 m and 2-3 seconds, respectively. Unfortunately, the vast majority of these studies have not reported the specific movement patterns of RSA, which is proposed as an important fitness component of team sports. Furthermore, there have been few studies that have investigated the physiological requirements of one-off, short-duration sprinting and repeated sprints (<10 seconds duration) that is specific to field-based team sports. This review examines the limited data concerning the metabolic changes occurring during this type of exercise, such as energy system contribution, adenosine triphosphate depletion and resynthesis, phosphocreatine degradation and resynthesis, glycolysis and glycogenolysis, and purine nucleotide loss. Assessment of RSA, as a training and research tool, is also discussed.

  20. Magnetic nanoparticles with high specific absorption rate of electromagnetic energy at low field strength for hyperthermia therapy.

    PubMed

    Shubitidze, Fridon; Kekalo, Katsiaryna; Stigliano, Robert; Baker, Ian

    2015-03-07

    Magnetic nanoparticles (MNPs), referred to as the Dartmouth MNPs, which exhibit high specific absorption rate at low applied field strength have been developed for hyperthermia therapy applications. The MNPs consist of small (2-5 nm) single crystals of gamma-Fe2O3 with saccharide chains implanted in their crystalline structure, forming 20-40 nm flower-like aggregates with a hydrodynamic diameter of 110-120 nm. The MNPs form stable (>12 months) colloidal solutions in water and exhibit no hysteresis under an applied quasistatic magnetic field, and produce a significant amount of heat at field strengths as low as 100 Oe at 99-164 kHz. The MNP heating mechanisms under an alternating magnetic field (AMF) are discussed and analyzed quantitatively based on (a) the calculated multi-scale MNP interactions obtained using a three dimensional numerical model called the method of auxiliary sources, (b) measured MNP frequency spectra, and (c) quantified MNP friction losses based on magneto-viscous theory. The frequency responses and hysteresis curves of the Dartmouth MNPs are measured and compared to the modeled data. The specific absorption rate of the particles is measured at various AMF strengths and frequencies, and compared to commercially available MNPs. The comparisons demonstrate the superior heating properties of the Dartmouth MNPs at low field strengths (<250 Oe). This may extend MNP hyperthermia therapy to deeper tumors that were previously non-viable targets, potentially enabling the treatment of some of the most difficult cancers, such as pancreatic and rectal cancers, without damaging normal tissue.

  1. Magnetic nanoparticles with high specific absorption rate of electromagnetic energy at low field strength for hyperthermia therapy

    PubMed Central

    Stigliano, Robert; Baker, Ian

    2015-01-01

    Magnetic nanoparticles (MNPs), referred to as the Dartmouth MNPs, which exhibit high specific absorption rate at low applied field strength have been developed for hyperthermia therapy applications. The MNPs consist of small (2–5 nm) single crystals of gamma-Fe2O3 with saccharide chains implanted in their crystalline structure, forming 20–40 nm flower-like aggregates with a hydrodynamic diameter of 110–120 nm. The MNPs form stable (>12 months) colloidal solutions in water and exhibit no hysteresis under an applied quasistatic magnetic field, and produce a significant amount of heat at field strengths as low as 100 Oe at 99–164 kHz. The MNP heating mechanisms under an alternating magnetic field (AMF) are discussed and analyzed quantitatively based on (a) the calculated multi-scale MNP interactions obtained using a three dimensional numerical model called the method of auxiliary sources, (b) measured MNP frequency spectra, and (c) quantified MNP friction losses based on magneto-viscous theory. The frequency responses and hysteresis curves of the Dartmouth MNPs are measured and compared to the modeled data. The specific absorption rate of the particles is measured at various AMF strengths and frequencies, and compared to commercially available MNPs. The comparisons demonstrate the superior heating properties of the Dartmouth MNPs at low field strengths (<250 Oe). This may extend MNP hyperthermia therapy to deeper tumors that were previously non-viable targets, potentially enabling the treatment of some of the most difficult cancers, such as pancreatic and rectal cancers, without damaging normal tissue. PMID:25825545

  2. Magnetic nanoparticles with high specific absorption rate of electromagnetic energy at low field strength for hyperthermia therapy

    NASA Astrophysics Data System (ADS)

    Shubitidze, Fridon; Kekalo, Katsiaryna; Stigliano, Robert; Baker, Ian

    2015-03-01

    Magnetic nanoparticles (MNPs), referred to as the Dartmouth MNPs, which exhibit high specific absorption rate at low applied field strength have been developed for hyperthermia therapy applications. The MNPs consist of small (2-5 nm) single crystals of gamma-Fe2O3 with saccharide chains implanted in their crystalline structure, forming 20-40 nm flower-like aggregates with a hydrodynamic diameter of 110-120 nm. The MNPs form stable (>12 months) colloidal solutions in water and exhibit no hysteresis under an applied quasistatic magnetic field, and produce a significant amount of heat at field strengths as low as 100 Oe at 99-164 kHz. The MNP heating mechanisms under an alternating magnetic field (AMF) are discussed and analyzed quantitatively based on (a) the calculated multi-scale MNP interactions obtained using a three dimensional numerical model called the method of auxiliary sources, (b) measured MNP frequency spectra, and (c) quantified MNP friction losses based on magneto-viscous theory. The frequency responses and hysteresis curves of the Dartmouth MNPs are measured and compared to the modeled data. The specific absorption rate of the particles is measured at various AMF strengths and frequencies, and compared to commercially available MNPs. The comparisons demonstrate the superior heating properties of the Dartmouth MNPs at low field strengths (<250 Oe). This may extend MNP hyperthermia therapy to deeper tumors that were previously non-viable targets, potentially enabling the treatment of some of the most difficult cancers, such as pancreatic and rectal cancers, without damaging normal tissue.

  3. From field barley to malt: detection and specification of microbial activity for quality aspects.

    PubMed

    Noots, I; Delcour, J A; Michiels, C W

    1999-01-01

    Barley grain carries a numerous, variable, and complex microbial population that mainly consists of bacteria, yeasts, and filamentous fungi and that can partly be detected and quantified using plating methods and microscopic and molecular techniques. The extent and the activity of this microflora are determined by the altering state of the grain and the environmental conditions in the malt production chain. Three ecological systems can be distinguished: the growing cereal in the field, the dry barley grain under storage, and the germinating barley kernel during actual malting. Microorganisms interact with the malting process both by their presence and by their metabolic activity. In this respect, interference with the oxygen uptake by the barley grain and secretion of enzymes, hormones, toxins, and acids that may affect the plant physiological processes have been studied. As a result of the interaction, microorganisms can cause important losses and influence malt quality as measured by brewhouse performance and beer quality. Of particular concern is the occurrence of mycotoxins that may affect the safety of malt. The development of the microflora during malt production can to a certain extent be controlled by the selection of appropriate process conditions. Physical and chemical treatments to inactivate the microbial population on the barley grain are suggested. Recent developments, however, aim to control the microbial activity during malt production by promoting the growth of desirable microbial cultures, selected either as biocontrol agents inhibiting mycotoxin-producing molds or as starter cultures actively contributing to malt modification. Such techniques may offer natural opportunities to improve the quality and safety of malt.

  4. Development of a rowing-specific VO2max field test.

    PubMed

    Huntsman, Heather D; DiPietro, Loretta; Drury, Daniel G; Miller, Todd A

    2011-06-01

    The purpose of this study was to develop an aerobic capacity test for rowers using minimal equipment that could be used in the field. Thirty rowers (15 men and 15 women) between the ages of 18 and 26 years were recruited on a volunteer basis from the District of Columbia metro area. The testing protocol consisted of a maximum of 7 2-minute stages on a rowing ergometer, separated by 30-second breaks where lactic acid concentrations were analyzed. Starting intensity for men was 200 W, although women started at 150 W, and each stage increased by 50 W. Expired gasses were collected during the test, and athletes were asked to row until maximal volition so that the directly measured VO2max could be compared to predicted values. Peak heart rates from each completed stage were plotted, and regression equations were calculated to predict VO2max. Separate regression equations were calculated for men and women. The predicted VO2max values were approximately 23 and 25% lower than what was actually achieved for men and women, respectively. Heart rate was a stronger correlate of VO2max in men compared with in women. Among men, we observed a moderate and statistically significant correlation (r = 0.55; p = 0.05), whereas among women, no such agreement was observed (r = -0.05; p > 0.85). The principle finding of this study was that the test was adequate in predicting VO2max in men but was inadequate in its prediction in women. With slight modifications to the testing protocol, stronger correlations and a more accurate prediction of VO2max is expected in men.

  5. Entirely Carbohydrate-Based Vaccines: An Emerging Field for Specific and Selective Immune Responses

    PubMed Central

    Nishat, Sharmeen; Andreana, Peter R.

    2016-01-01

    Carbohydrates are regarded as promising targets for vaccine development against infectious disease because cell surface glycans on many infectious agents are attributed to playing an important role in pathogenesis. In addition, oncogenic transformation of normal cells, in many cases, is associated with aberrant glycosylation of the cell surface glycan generating tumor associated carbohydrate antigens (TACAs). Technological advances in glycobiology have added a new dimension to immunotherapy when considering carbohydrates as key targets in developing safe and effective vaccines to combat cancer, bacterial infections, viral infections, etc. Many consider effective vaccines induce T-cell dependent immunity with satisfactory levels of immunological memory that preclude recurrence. Unfortunately, carbohydrates alone are poorly immunogenic as they do not bind strongly to the MHCII complex and thus fail to elicit T-cell immunity. To increase immunogenicity, carbohydrates have been conjugated to carrier proteins, which sometimes can impede carbohydrate specific immunity as peptide-based immune responses can negate antibodies directed at the targeted carbohydrate antigens. To overcome many challenges in using carbohydrate-based vaccine design and development approaches targeting cancer and other diseases, zwitterionic polysaccharides (ZPSs), isolated from the capsule of commensal anaerobic bacteria, will be discussed as promising carriers of carbohydrate antigens to achieve desired immunological responses. PMID:27213458

  6. Genetic and phenotypic parameters estimated from Nebraska specific-pathogen-free swine field records.

    PubMed

    David, P J; Johnson, R K; Socha, T E

    1983-11-01

    Records collected during 1971 through 1979 from 101,606 hogs raised in 18 Nebraska Specific Pathogen Free herds were analyzed. Traits considered were backfat at 100 kg (BF), weight at 140 d of age (WT) and, in some analyses, number of live pigs/litter at birth (NBA). The phenotypic correlation of BF and WT, averaged across herds, was -.07. The correlations between BF and NBA and between WT and NBA were .04 and -.05, respectively. Average phenotypic standard deviations for BF, WT and NBA were 2.6 mm, 8.8 kg and 2.0 pigs. Estimates of the heritability of BF and WT were lower than most estimates reported from university research herds. Within breed, herd and sex estimates of heritability ranged from -.22 and .51 (unweighted mean = .16 +/- .025) for BF and ranged from -.28 to .49 (mean = .16 +/- .016) for WT. Estimates of the genetic correlation between BF and WT were extremely variable (mean = -.62 +/- 14.3, range = -9.42 to 1.30) among breed-herd-sex subclasses.

  7. Plasmodium-Specific Molecular Assays Produce Uninterpretable Results and Non-Plasmodium spp. Sequences in Field-Collected Anopheles Vectors

    PubMed Central

    Harrison, Genelle F.; Foley, Desmond H.; Rueda, Leopoldo M.; Melanson, Vanessa R.; Wilkerson, Richard C.; Long, Lewis S.; Richardson, Jason H.; Klein, Terry A.; Kim, Heung-Chul; Lee, Won-Ja

    2013-01-01

    The Malaria Research and Reference Reagent Resource–recommended PLF/UNR/VIR polymerase chain reaction (PCR) was used to detect Plasmodium vivax in Anopheles spp. mosquitoes collected in South Korea. Samples that were amplified were sequenced and compared with known Plasmodium spp. by using the PlasmoDB.org Basic Local Alignment Search Tool/n and the National Center for Biotechnology Information Basic Local Alignment Search Tool/n tools. Results show that the primers PLF/UNR/VIR used in this PCR can produce uninterpretable results and non-specific sequences in field-collected mosquitoes. Three additional PCRs (PLU/VIV, specific for 18S small subunit ribosomal DNA; Pvr47, specific for a nuclear repeat; and GDCW/PLAS, specific for the mitochondrial marker, cytB) were then used to find a more accurate and interpretable assay. Samples that were amplified were again sequenced. The PLU/VIV and Pvr47 assays showed cross-reactivity with non-Plasmodium spp. and an arthropod fungus (Zoophthora lanceolata). The GDCW/PLAS assay amplified only Plasmodium spp. but also amplified the non-human specific parasite P. berghei from an Anopheles belenrae mosquito. Detection of P. berghei in South Korea is a new finding. PMID:24189365

  8. Plasmodium-specific molecular assays produce uninterpretable results and non-Plasmodium spp. sequences in field-collected Anopheles vectors.

    PubMed

    Harrison, Genelle F; Foley, Desmond H; Rueda, Leopoldo M; Melanson, Vanessa R; Wilkerson, Richard C; Long, Lewis S; Richardson, Jason H; Klein, Terry A; Kim, Heung-Chul; Lee, Won-Ja

    2013-12-01

    The Malaria Research and Reference Reagent Resource-recommended PLF/UNR/VIR polymerase chain reaction (PCR) was used to detect Plasmodium vivax in Anopheles spp. mosquitoes collected in South Korea. Samples that were amplified were sequenced and compared with known Plasmodium spp. by using the PlasmoDB.org Basic Local Alignment Search Tool/n and the National Center for Biotechnology Information Basic Local Alignment Search Tool/n tools. Results show that the primers PLF/UNR/VIR used in this PCR can produce uninterpretable results and non-specific sequences in field-collected mosquitoes. Three additional PCRs (PLU/VIV, specific for 18S small subunit ribosomal DNA; Pvr47, specific for a nuclear repeat; and GDCW/PLAS, specific for the mitochondrial marker, cytB) were then used to find a more accurate and interpretable assay. Samples that were amplified were again sequenced. The PLU/VIV and Pvr47 assays showed cross-reactivity with non-Plasmodium spp. and an arthropod fungus (Zoophthora lanceolata). The GDCW/PLAS assay amplified only Plasmodium spp. but also amplified the non-human specific parasite P. berghei from an Anopheles belenrae mosquito. Detection of P. berghei in South Korea is a new finding.

  9. Revisiting the scaling of the specific heat of the three-dimensional random-field Ising model

    NASA Astrophysics Data System (ADS)

    Fytas, Nikolaos G.; Theodorakis, Panagiotis E.; Hartmann, Alexander K.

    2016-09-01

    We revisit the scaling behavior of the specific heat of the three-dimensional random-field Ising model with a Gaussian distribution of the disorder. Exact ground states of the model are obtained using graph-theoretical algorithms for different strengths 𝒩 = 268 3 spins. By numerically differentiating the bond energy with respect to h, a specific-heat-like quantity is obtained whose maximum is found to converge to a constant in the thermodynamic limit. Compared to a previous study following the same approach, we have studied here much larger system sizes with an increased statistical accuracy. We discuss the relevance of our results under the prism of a modified Rushbrooke inequality for the case of a saturating specific heat. Finally, as a byproduct of our analysis, we provide high-accuracy estimates of the critical field h c = 2.279(7) and the critical exponent of the correlation exponent ν = 1.37(1), in excellent agreement to the most recent computations in the literature.

  10. Settling Velocity Specific SOC Distribution along Hillslopes - A field investigation in Denmark

    NASA Astrophysics Data System (ADS)

    Kuhn, N. J.; Hu, Y.

    2015-12-01

    The net effects of soil erosion by water, as a sink or source of atmospheric CO2, are decisively affected by the spatial re-distribution and stability of eroded soil organic carbon (SOC). The deposition position of eroded SOC, into terrestrial or aquatic systems, is actually decided by the transport distances of soil fractions where the SOC is stored. In theory, the transport distances of aggregated soil fractions are related to their settling velocities under given layer conditions. Yet, little field investigation has been conducted to examine the actual movement of eroded soil fractions along hillslopes, let alone the re-distribution pattern of functional SOC fractions. Eroding sandy soils and sediment were sampled after a series of rainfall events from different topographic positions along a slope on a freshly seeded cropland in Jutland, Denmark. All the soil samples from difference topographic positions along the slope were fractionated into five settling classes using a settling tube apparatus. The SOC content, 13C signature, and C:N ratios of all settling fractions were measured. Our results show that: 1) the spatial distribution of soil settling classes along the slope clearly shows a coarsening effect at the deposition area immediately below the eroding slope, followed by a fining trend on the deposition area at the slope tail. This proves the validity of the conceptual model in Starr et al. 2000 to predict SOC redistribution patterns along eroding hillslopes. 2) The isotopically enriched 13C on the slope back suggests greater decomposition rates possibly experienced by eroded SOC during transport, while the pronounced respiration rates at the slope tail indicate a great potential of CO2 emissions after deposition. Overall, our results illustrate that immediate deposition of fast settling soil fractions, and the thus induced preferential deposition of SOC at foot slope and potential CO2 emissions during transport, must be appropriately accounted for in

  11. Minimizing the magnetic field effect in MR-linac specific QA-tests: the use of electron dense materials

    NASA Astrophysics Data System (ADS)

    van Zijp, H. M.; van Asselen, B.; Wolthaus, J. W. H.; Kok, J. M. G.; de Vries, J. H. W.; Ishakoglu, K.; Beld, E.; Lagendijk, J. J. W.; Raaymakers, B. W.

    2016-02-01

    To address the quality assurance (QA) of a MR-linac which is an MRI combined with a linear accelerator (linac), the traditional linac QA-tests need to be redesigned, since the presence of the static magnetic field in the MR-linac alters the electron trajectory. The latter causes the asymmetry in the dose kernel which is introduced by the magnetic field and hinders accurate geometrical QA-tests for the MR-linac. We introduced the use of electron dense materials (e.g. copper) to reduce the size of the dose kernel and thereby the magnetic field effect on the dose deposition. Two examples of QA-tests are presented in which the geometrical accuracy of the MR-linac was addressed; beam profile and star-shot measurements. The introduced setup was compared with a reference setup and both were tested on a conventional and the MR-linac. The results showed that the symmetry of the recorded beam profile was restored in presence of the copper material and that the isocenter size of the MR-linac can be determined accurately with the introduced star-shot setup. The use of electron dense materials is not limited to the presented QA-tests but has a broad application for beam-specific QA-tests in presence of a magnetic field.

  12. Minimizing the magnetic field effect in MR-linac specific QA-tests: the use of electron dense materials.

    PubMed

    van Zijp, H M; van Asselen, B; Wolthaus, J W H; Kok, J M G; de Vries, J H W; Ishakoglu, K; Beld, E; Lagendijk, J J W; Raaymakers, B W

    2016-02-07

    To address the quality assurance (QA) of a MR-linac which is an MRI combined with a linear accelerator (linac), the traditional linac QA-tests need to be redesigned, since the presence of the static magnetic field in the MR-linac alters the electron trajectory. The latter causes the asymmetry in the dose kernel which is introduced by the magnetic field and hinders accurate geometrical QA-tests for the MR-linac. We introduced the use of electron dense materials (e.g. copper) to reduce the size of the dose kernel and thereby the magnetic field effect on the dose deposition. Two examples of QA-tests are presented in which the geometrical accuracy of the MR-linac was addressed; beam profile and star-shot measurements. The introduced setup was compared with a reference setup and both were tested on a conventional and the MR-linac. The results showed that the symmetry of the recorded beam profile was restored in presence of the copper material and that the isocenter size of the MR-linac can be determined accurately with the introduced star-shot setup. The use of electron dense materials is not limited to the presented QA-tests but has a broad application for beam-specific QA-tests in presence of a magnetic field.

  13. Tonotopic and Field-Specific Representation of Long-Lasting Sustained Activity in Rat Auditory Cortex

    PubMed Central

    Shiramatsu, Tomoyo I.; Noda, Takahiro; Akutsu, Kan; Takahashi, Hirokazu

    2016-01-01

    Cortical information processing of the onset, offset, and continuous plateau of an acoustic stimulus should play an important role in acoustic object perception. To date, transient activities responding to the onset and offset of a sound have been well investigated and cortical subfields and topographic representation in these subfields, such as place code of sound frequency, have been well characterized. However, whether these cortical subfields with tonotopic representation are inherited in the sustained activities that follow transient activities and persist during the presentation of a long-lasting stimulus remains unknown, because sustained activities do not exhibit distinct, reproducible, and time-locked responses in their amplitude to be characterized by grand averaging. To address this gap in understanding, we attempted to decode sound information from densely mapped sustained activities in the rat auditory cortex using a sparse parameter estimation method called sparse logistic regression (SLR), and investigated whether and how these activities represent sound information. A microelectrode array with a grid of 10 × 10 recording sites within an area of 4.0 mm × 4.0 mm was implanted in the fourth layer of the auditory cortex in rats under isoflurane anesthesia. Sustained activities in response to long-lasting constant pure tones were recorded. SLR then was applied to discriminate the sound-induced band-specific power or phase-locking value from those of spontaneous activities. The highest decoding performance was achieved in the high-gamma band, indicating that cortical inhibitory interneurons may contribute to the sparse tonotopic representation in sustained activities by mediating synchronous activities. The estimated parameter in the SLR decoding revealed that the informative recording site had a characteristic frequency close to the test frequency. In addition, decoding of the four test frequencies demonstrated that the decoding performance of the SLR

  14. Inductively coupled plasma-mass spectrometry as an element-specific detector for field-flow fractionation particle separation

    USGS Publications Warehouse

    Taylor, Howard E.; Garbarino, John R.; Murphy, Deirdre M.; Beckett, Ronald

    1992-01-01

    An inductively coupled plasma-mass spectrometer was used for the quantitative measurement of trace elements In specific,submicrometer size-fraction particulates, separated by sedimentation field-flow fractionation. Fractions were collected from the eluent of the field-flow fractionation centrifuge and nebulized, with a Babington-type pneumatic nebulizer, into an argon inductively coupled plasma-mass spectrometer. Measured Ion currents were used to quantify the major, minor, and trace element composition of the size-separated colloidal (< 1-microm diameter) particulates. The composition of surface-water suspended matter collected from the Yarra and Darling rivers in Australia is presented to illustrate the usefulness of this tool for characterizing environmental materials. An adsorption experiment was performed using cadmium lon to demonstrate the utility for studying the processes of trace metal-suspended sediment interactions and contaminant transport in natural aquatic systems.

  15. Laboratory and field experimental evaluation of host plant specificity of Aceria solstitialis, a prospective biological control agent of yellow starthistle.

    PubMed

    Stoeva, Atanaska; Harizanova, Vili; de Lillo, Enrico; Cristofaro, Massimo; Smith, Lincoln

    2012-01-01

    Centaurea solstitialis (yellow starthistle, Asteraceae) is an invasive annual weed in the western USA that is native to the Mediterranean Region and is a target for classical biological control. Aceria solstitialis is an eriophyid mite that has been found exclusively in association with Ce. solstitialis in Italy, Greece, Turkey and Bulgaria. The mite feeds on leaf tissue and damages bolting plants, causing stunting, witch's broom and incomplete flower development. Field experiments and laboratory no-choice and two-way choice experiments were conducted to assess host plant specificity of the mite in Bulgaria. Mites showed the highest degree of host specificity in the field and lowest in the no-choice experiments. In the field, highest densities of mites occurred on Ce. solstitialis and Ce. cyanus (bachelor's button), and either no mites or trace numbers occurred on the other test plants: Ce. diffusa (diffuse knapweed), Carthamus tinctorius (safflower) and Cynara scolymus (artichoke). In no-choice experiments, mites persisted for 60 days on Ce. diffusa, Ce. cyanus, Ce. solstitialis, Ca. tinctorius and Cy. scolymus, whereas in two-way choice experiments mites persisted on 25% of Cy. scolymus plants for 60 days and did not persist on Ca. tinctorius beyond 40 days. The eight other species of plants that were tested in the laboratory were less suitable for the mite. These results suggest that although A. solstitialis can persist on some nontarget plants for as long as 60 days in the laboratory, it appears to be much more specific under natural conditions, and warrants further evaluation as a prospective biological control agent.

  16. A Feasibility Study of a Field-specific Weather Service for Small-scale Farms in a Topographically Complex Watershed

    NASA Astrophysics Data System (ADS)

    Kim, S. O.; Shim, K. M.; Shin, Y. S.; Yun, J. I.

    2015-12-01

    Adequate downscaling of synoptic forecasts is a prerequisite for improved agrometeorological service to rural areas in South Korea where complex terrain and small farms are common. Geospatial schemes based on topoclimatology were used to scale down the Korea Meteorological Administration (KMA) temperature forecasts to the local scale (~30 m) across a rural catchment. Local temperatures were estimated at 14 validation sites at 0600 and 1500 LST in 2013/2014 using these schemes and were compared with observations. A substantial reduction in the estimation error was found for both 0600 and 1500 temperatures compared with uncorrected KMA products. Improvement was most remarkable at low lying locations for the 0600 temperature and at the locations on west- and south-facing slopes for the 1500 temperature. Using the downscaled real-time temperature data, a pilot service has started to provide field-specific weather information tailored to meet the requirements of small-scale farms. For example, the service system makes a daily outlook on the phenology of crop species grown in a given field using the field-specific temperature data. When the temperature forecast is given for tomorrow morning, a frost risk index is calculated according to a known phenology-frost injury relationship. If the calculated index is higher than a pre-defined threshold, a warning is issued and delivered to the grower's cellular phone with relevant countermeasures to help protect crops against frost damage. The system was implemented for a topographically complex catchment of 350km2with diverse agricultural activities, and more than 400 volunteer farmers are participating in this pilot service to access user-specific weather information.

  17. Design of an ecological momentary assessment study of exposure to radiofrequency electromagnetic fields and non-specific physical symptoms

    PubMed Central

    Bogers, Rik P; Bolte, John F B; Houtveen, Jan H; Lebret, Erik; van Strien, Rob T; Schipper, C Maarten A; Alkadhimi, Mehdi; Baliatsas, Christos; van Kamp, Irene

    2013-01-01

    Introduction Idiopathic Environmental Intolerance (IEI) attributed to electromagnetic fields (EMF) refers to self-reported sensitivity mainly characterised by the attribution of non-specific physical symptoms to low-level EMF exposure emitted from sources such as mobile phones. Scientific studies have not provided evidence for the existence of IEI-EMF, but these studies did not resemble the real-life situation or suffered from poor exposure characterisation and biased recall of health symptoms. To improve existing methods for the study of IEI-EMF, an Ecological Momentary Assessment (EMA) study is designed. Methods and analysis The study is an EMA study in which respondents carry personal exposure metres (exposimeters) that measure radiofrequency (RF) EMF, with frequent assessment of health symptoms and perceived EMF exposure through electronic diary registration during five consecutive days. Participants will be a selection from an epidemiological study who report to be sensitive to RF EMF. The exposimeters measure electric field strength in 12 frequency bands. Diary questions include the occurrence and severity of 10 non-specific physical symptoms, mood states and perceived exposure to (sources of) EMF. The relationship of actual and perceived EMF exposure and mood with non-specific physical symptoms will be analysed using multilevel regression analysis with time-shift models. Discussion The study has several advantages over previous studies, including assessment of personal EMF exposure and non-specific physical symptoms by an ecological method with a minimised chance of recall bias. The within-person design reduces confounding by time-stable factors (eg, personal characteristics). In the conduct of the study and the analysis and interpretation of its outcomes, some methodological issues including a high participant burden, reactivity, compliance to the study protocol and the potential of chance findings due to multiple statistical testing will be accounted for

  18. Field applicability of Compound-Specific Isotope Analysis (CSIA) for characterization and quantification of in situ contaminant degradation in aquifers.

    PubMed

    Braeckevelt, M; Fischer, A; Kästner, M

    2012-06-01

    Microbial processes govern the fate of organic contaminants in aquifers to a major extent. Therefore, the evaluation of in situ biodegradation is essential for the implementation of Natural Attenuation (NA) concepts in groundwater management. Laboratory degradation experiments and biogeochemical approaches are often biased and provide only indirect evidence of in situ degradation potential. Compound-Specific Isotope Analysis (CSIA) is at present among the most promising tools for assessment of the in situ contaminant degradation within aquifers. One- and two-dimensional (2D) CSIA provides qualitative and quantitative information on in situ contaminant transformation; it is applicable for proving in situ degradation and characterizing degradation conditions and reaction mechanisms. However, field application of CSIA is challenging due to a number of influencing factors, namely those affecting the observed isotope fractionation during biodegradation (e.g., non-isotope-fractionating rate-limiting steps, limited bioavailability), potential isotope effects caused by processes other than biodegradation (e.g., sorption, volatilization, diffusion), as well as non-isotope-fractionating physical processes such as dispersion and dilution. This mini-review aims at guiding practical users towards the sound interpretation of CSIA field data for the characterization of in situ contaminant degradation. It focuses on the relevance of various constraints and influencing factors in CSIA field applications and provides advice on when and how to account for these constraints. We first evaluate factors that can influence isotope fractionation during biodegradation, as well as potential isotope-fractionating and non-isotope-fractionating physical processes governing observed isotope fractionation in the field. Finally, the potentials of the CSIA approach for site characterization and the proper ways to account for various constraints are illustrated by means of a comprehensive CSIA field

  19. Measurement of gamma field parameters in core with LEU fuel IRT-4M using TL detectors

    SciTech Connect

    Bily, T.

    2008-07-15

    Thermoluminescent dosimeters represent very useful tool for gamma fields parameters measurements at nuclear research reactors, especially at zero power ones. {sup 7}LiF:Mg,Ti and {sup 7}LiF:Mg,Cu,P type TL dosimeters enable determination of only gamma component in mixed neutron - gamma field. At VR-1 reactor operated within the Faculty of Nuclear Sciences and Physical Engineering at the Czech Technical University in Prague the integral characteristics of gamma rays field were investigated, especially its spatial distribution and time behaviour, i.e. the non-saturated delayed gamma ray emission influence. Measured spatial distributions were compared with monte carlo code MCNP5 calculations. Although MCNP cannot generate delayed gamma rays from fission, the relative gamma dose rate distribution is within {+-} 15% with measured values. The experiments were carried out with core configuration C1 consisting of LEU fuel IRT-4M (19.7 %). (author)

  20. An Nkx2-5/Bmp2/Smad1 negative feedback loop controls second heart field progenitor specification and proliferation

    PubMed Central

    Prall, Owen WJ; Menon, Mary K; Solloway, Mark J; Watanabe, Yusuke; Zaffran, Stéphane; Bajolle, Fanny; Biben, Christine; McBride, Jim J; Robertson, Bronwyn R; Chaulet, Hervé; Stennard, Fiona A; Wise, Natalie; Schaft, Daniel; Wolstein, Orit; Furtado, Milena B; Shiratori, Hidetaka; Chien, Kenneth R; Hamada, Hiroshi; Black, Brian L; Saga, Yumiko; Robertson, Elizabeth J; Buckingham, Margaret E; Harvey, Richard P

    2007-01-01

    Summary During heart development the second heart field (SHF) provides progenitor cells for most cardiomyocytes and expresses the homeodomain factor Nkx2-5. We now show that feedback repression of Bmp2/Smad1 signaling by Nkx2-5 critically regulates SHF proliferation and outflow tract (OFT) morphology. In the cardiac fields of Nkx2-5 mutants, genes controlling cardiac specification (including Bmp2) and maintenance of the progenitor state were up-regulated, leading initially to progenitor over-specification, but subsequently to failed SHF proliferation and OFT truncation. In Smad1 mutants, SHF proliferation and deployment to the OFT were increased, while Smad1 deletion in Nkx2-5 mutants rescued SHF proliferation and OFT development. In Nkx2-5 hypomorphic mice, which recapitulate human congenital heart disease (CHD), OFT anomalies were also rescued by Smad1 deletion. Our findings demonstrate that Nkx2-5 orchestrates the transition between periods of cardiac induction, progenitor proliferation and OFT morphogenesis via a Smad1-dependent negative feedback loop, which may be a frequent molecular target in CHD. PMID:17350578

  1. Specific absorption rate dependence on temperature in magnetic field hyperthermia measured by dynamic hysteresis losses (ac magnetometry).

    PubMed

    Garaio, Eneko; Sandre, Olivier; Collantes, Juan-Mari; Garcia, Jose Angel; Mornet, Stéphane; Plazaola, Fernando

    2015-01-09

    Magnetic nanoparticles (NPs) are intensively studied for their potential use for magnetic hyperthermia, a treatment that has passed a phase II clinical trial against severe brain cancer (glioblastoma) at the end of 2011. Their heating power, characterized by the 'specific absorption rate (SAR)', is often considered temperature independent in the literature, mainly because of the difficulties that arise from the measurement methodology. Using a dynamic magnetometer presented in a recent paper, we measure here the thermal dependence of SAR for superparamagnetic iron oxide (maghemite) NPs of four different size-ranges corresponding to mean diameters around 12 nm, 14 nm, 15 nm and 16 nm. The article reports a parametrical study extending from 10 to 60 °C in temperature, from 75 to 1031 kHz in frequency, and from 2 to 24 kA m(-1) in magnetic field strength. It was observed that SAR values of smaller NPs decrease with temperature whereas for the larger sample (16 nm) SAR values increase with temperature. The measured variation of SAR with temperature is frequency dependent. This behaviour is fully explained within the scope of linear response theory based on Néel and Brown relaxation processes, using independent magnetic measurements of the specific magnetization and the magnetic anisotropy constant. A good quantitative agreement between experimental values and theoretical values is confirmed in a tri-dimensional space that uses as coordinates the field strength, the frequency and the temperature.

  2. Specific absorption rate dependence on temperature in magnetic field hyperthermia measured by dynamic hysteresis losses (ac magnetometry)

    NASA Astrophysics Data System (ADS)

    Garaio, Eneko; Sandre, Olivier; Collantes, Juan-Mari; Garcia, Jose Angel; Mornet, Stéphane; Plazaola, Fernando

    2015-01-01

    Magnetic nanoparticles (NPs) are intensively studied for their potential use for magnetic hyperthermia, a treatment that has passed a phase II clinical trial against severe brain cancer (glioblastoma) at the end of 2011. Their heating power, characterized by the ‘specific absorption rate (SAR)’, is often considered temperature independent in the literature, mainly because of the difficulties that arise from the measurement methodology. Using a dynamic magnetometer presented in a recent paper, we measure here the thermal dependence of SAR for superparamagnetic iron oxide (maghemite) NPs of four different size-ranges corresponding to mean diameters around 12 nm, 14 nm, 15 nm and 16 nm. The article reports a parametrical study extending from 10 to 60 {}^\\circ C in temperature, from 75 to 1031 kHz in frequency, and from 2 to 24 kA m-1 in magnetic field strength. It was observed that SAR values of smaller NPs decrease with temperature whereas for the larger sample (16 nm) SAR values increase with temperature. The measured variation of SAR with temperature is frequency dependent. This behaviour is fully explained within the scope of linear response theory based on Néel and Brown relaxation processes, using independent magnetic measurements of the specific magnetization and the magnetic anisotropy constant. A good quantitative agreement between experimental values and theoretical values is confirmed in a tri-dimensional space that uses as coordinates the field strength, the frequency and the temperature.

  3. Patient-Specific Quality Assurance for Prostate Cancer Patients Receiving Spot Scanning Proton Therapy Using Single-Field Uniform Dose

    SciTech Connect

    Zhu, X. Ronald; Poenisch, Falk; Song, Xiaofei; Johnson, Jennifer L.; Ciangaru, George; Taylor, M. Brad; Lii, Ming Fwu; Martin, Craig; Arjomandy, Bijan; Lee, Andrew K.; Choi, Seungtaek; Nguyen, Quynh nhu; Gillin, Michael T.; Sahoo, Narayan

    2011-10-01

    Purpose: To describe our experiences with patient-specific quality assurance (QA) for patients with prostate cancer receiving spot scanning proton therapy (SSPT) using single-field uniform dose (SFUD). Methods and Materials: The first group of 249 patients with prostate cancer treated with SSPT using SFUD was included in this work. The scanning-beam planning target volume and number of monitor units were recorded and checked for consistency. Patient-specific dosimetric measurements were performed, including the point dose for each plan, depth doses, and two-dimensional (2D) dose distribution in the planes perpendicular to the incident beam direction for each field at multiple depths. The {gamma}-index with 3% dose or 3-mm distance agreement criteria was used to evaluate the 2D dose distributions. Results: We observed a linear relationship between the number of monitor units and scanning-beam planning target volume. The difference between the measured and calculated point doses (mean {+-} SD) was 0.0% {+-} 0.7% (range, -2.9% to 1.8%). In general, the depth doses exhibited good agreement except at the distal end of the spread-out Bragg peak. The pass rate of {gamma}-index (mean {+-} SD) for 2D dose comparison was 96.2% {+-} 2.6% (range, 90-100%). Discrepancies between the measured and calculated dose distributions primarily resulted from the limitation of the model used by the treatment planning system. Conclusions: We have established a patient-specific QA program for prostate cancer patients receiving SSPT using SFUD.

  4. From usability requirement to technical specifications for hand-held tools and materials: an applied research in the construction field.

    PubMed

    Duca, Gabriella; Attaianese, Erminia

    2012-01-01

    Literature shows incidence of musculoskeletal disorders in bricklaying workers as well as the relevance of good designed hand-held tools in musculoskeletal disorders prevention. In this framework, it can be supposed that providing usable hand-held tools and material in construction worksites will help to improve bricklayers' working conditions. Here a study is presented aimed at framing a methodology for usability assessment of bricklayers handled objects, in order to provide employers with practical indicators for choosing tools and materials best fitting workers needs, under the effectiveness, efficiency and satisfaction perspective. On the basis of a task analysis, usability requirements for bricklaying hand-held tools and materials have been detailed and related, quantitative and qualitative, technical specifications have been elicited. Theoretical framework and usability assessment methodology are presented and, finally, findings from a field application are discussed.

  5. Evaluation of the reliability and validity of a soccer-specific field test of repeated sprint ability.

    PubMed

    Wragg, C B; Maxwell, N S; Doust, J H

    2000-09-01

    The reliability and validity of a soccer-specific field test of repeated sprint ability was assessed. Seven male games players performed the repeated sprint test on six separate occasions. The temporal pattern of the mean sprint time was analysed by using coefficient of variation with confidence intervals (CI), and repeated measures ANOVA. A within subject mean coefficient of variation of 1.8% (95% CI, 1.5-2.4) was found for performance in the repeated sprint test across all six trials. The mean coefficient of variation across trials 2-4 was found to be 1.9% (95% CI, 1.3-3.1), compared to trials 4-6, where it was 1.4% (95% CI, 1.0-2.3). The ANOVA showed that a significant difference was present between the trials (F6,30 9.8. P<0.001). A Tukey post-hoc test showed that significant differences were present between trial I and trials 3-6, and trial 2 and trial 5. The learning effect was complete by trial 3. Performance in the repeated sprint test was compared to total running time averaged from two repeats of the maximal anaerobic running test laboratory protocol. Mean sprint time in the repeated sprint test and total running time in the laboratory protocol had a correlation coefficient of r = -0.298 (P = 0.516, n = 7), suggesting that the energetics of the two tests are not closely related. In conclusion, this soccer-specific field test demonstrated high reliability.

  6. Recent Results From Internal and Very-Near-Field Plasma Diagnostics of a High Specific Impulse Hall Thruster

    NASA Technical Reports Server (NTRS)

    Hofer, Richard R.; Gallimore, Alec D.; Jacobson, David (Technical Monitor)

    2003-01-01

    Floating potential and ion current density measurements were taken on the laboratory model NASA-173Mv2 in order to improve understanding of the physical processes affecting Hall thruster performance at high specific impulse. Floating potential was measured on discharge chamber centerline over axial positions spanning 10 mm from the anode to 100 mm downstream of the exit plane. Ion current density was mapped radially up to 300 mm from thruster centerline over axial positions in the very-near-field (10 to 250 mm from the exit plane). All data were collected using a planar probe in conjunction with a high-speed translation stage to minimize probe-induced thruster perturbations. Measurements of floating potential at a xenon flow rate of 10 mg/s have shown that the acceleration layer moved upstream 3 1 mm when the voltage increased from 300 to 600 V. The length of the acceleration layer was 14 2 mm and was approximately constant with voltage and magnetic field. Ion current density measurements indicated the annular ion beam crossed the thruster centerline 163 mm downstream of the exit plane. Radial integration of the ion current density at the cathode plane provided an estimate of the ion current fraction. At 500 V and 5 mg/s, the ion current fraction was calculated as 0.77.

  7. Time-specific measurements of energy deposition from radiation fields in simulated sub-micron tissue volumes

    SciTech Connect

    Famiano, M.A.

    1997-07-07

    A tissue-equivalent spherical proportional counter is used with a modified amplifier system to measure specific energy deposited from a uniform radiation field for short periods of time ({approximately}1 {micro}s to seconds) in order to extrapolate to dose in sub-micron tissue volumes. The energy deposited during these time intervals is compared to biological repair processes occurring within the same intervals after the initial energy deposition. The signal is integrated over a variable collection time which is adjusted with a square-wave pulse. Charge from particle passages is collected on the anode during the period in which the integrator is triggered, and the signal decays quickly to zero after the integrator feedback switch resets; the process repeats for every triggering pulse. Measurements of energy deposited from x rays, {sup 137}Cs gamma rays, and electrons from a {sup 90}Sr/{sup 90}Y source for various time intervals are taken. Spectral characteristics as a function of charge collection time are observed and frequency plots of specific energy and collection time-interval are presented. In addition, a threshold energy flux is selected for each radiation type at which the formation of radicals (based on current measurements) in mammalian cells equals the rate at which radicals are repaired.

  8. Low frequency pulsed electromagnetic field affects proliferation, tissue-specific gene expression, and cytokines release of human tendon cells.

    PubMed

    de Girolamo, L; Stanco, D; Galliera, E; Viganò, M; Colombini, A; Setti, S; Vianello, E; Corsi Romanelli, M M; Sansone, V

    2013-07-01

    Low frequency pulsed electromagnetic field (PEMF) has proven to be effective in the modulation of bone and cartilage tissue functional responsiveness, but its effect on tendon tissue and tendon cells (TCs) is still underinvestigated. PEMF treatment (1.5 mT, 75 Hz) was assessed on primary TCs, harvested from semitendinosus and gracilis tendons of eight patients, under different experimental conditions (4, 8, 12 h). Quantitative PCR analyses were conducted to identify the possible effect of PEMF on tendon-specific gene transcription (scleraxis, SCX and type I collagen, COL1A1); the release of pro- and anti-inflammatory cytokines and of vascular endothelial growth factor (VEGF) was also assessed. Our findings show that PEMF exposure is not cytotoxic and is able to stimulate TCs' proliferation. The increase of SCX and COL1A1 in PEMF-treated cells was positively correlated to the treatment length. The release of anti-inflammatory cytokines in TCs treated with PEMF for 8 and 12 h was significantly higher in comparison with untreated cells, while the production of pro-inflammatory cytokines was not affected. A dramatically higher increase of VEGF-A mRNA transcription and of its related protein was observed after PEMF exposure. Our data demonstrated that PEMF positively influence, in a dose-dependent manner, the proliferation, tendon-specific marker expression, and release of anti-inflammatory cytokines and angiogenic factor in a healthy human TCs culture model.

  9. Site-specific distribution and competitive ability of indigenous bean-nodulating rhizobia isolated from organic fields in Minnesota.

    PubMed

    Wongphatcharachai, Manoosak; Wang, Ping; Staley, Christopher; Chun, Chan Lan; Ferguson, John A; Moncada, Kristine M; Sheaffer, Craig C; Sadowsky, Michael J

    2015-11-20

    Organic dry bean production systems have received increasing interest in many regions of the US, including Minnesota. Thus, improving biological N2 fixation would be highly beneficial for organic crop production. To date, only limited work has been done to select efficient N2-fixing rhizobia for organic dry bean production. In this study, soil samples from 25 organic fields in Minnesota, with a previous cropping history of dry beans, soybeans or both, were collected during May to July 2012. Genetic diversity of indigenous dry bean-rhizobia (511 isolates) was determined by using horizontal, fluorophore-enhanced, repetitive, extragenic, and palindromic-PCR (HFERP) DNA fingerprinting and isolates were classified as belonging to 58 different genotypes. The more abundant rhizobia isolated from bean nodules comprised 35.6% of the population. None of the isolates were identical to commonly-used commercial strains used in the U.S., including Rhizobium tropici CIAT899. Seventeen predominant genotypes were shown to represent two main species, Rhizobium leguminosarum bv. phaseoli (67.1%) and Rhizobium etli (30.2%). One of the indigenous strains, orgK9, displayed efficient N2-fixation and competitive ability relative to the commercial strains tested. The lack of large numbers of indigenous dry bean-rhizobia at most study sites will be useful to avoid competition problems between inoculant strains and indigenous rhizobia. This will allow inoculation with highly effective N2-fixing rhizobia, thus resulting in improved crop productivity. Our results highlight the existence of site-specific rhizobial genotypes in different organic fields and identify strains that may prove useful as novel inoculants for organic dry bean production systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Convergence of a head-field selector Otx2 and Notch signaling: a mechanism for lens specification.

    PubMed

    Ogino, Hajime; Fisher, Marilyn; Grainger, Robert M

    2008-01-01

    Xenopus is ideal for systematic decoding of cis-regulatory networks because its evolutionary position among vertebrates allows one to combine comparative genomics with efficient transgenic technology in one system. Here, we have identified and analyzed the major enhancer of FoxE3 (Lens1), a gene essential for lens formation that is activated in the presumptive lens ectoderm (PLE) when commitment to the lens fate occurs. Deletion and mutation analyses of the enhancer based on comparison of Xenopus and mammalian sequences and in vitro and in vivo binding assays identified two essential transcriptional regulators: Otx2, a homeodomain protein expressed broadly in head ectoderm including the PLE, and Su(H), a nuclear signal transducer of Notch signaling. A Notch ligand, Delta2, is expressed in the optic vesicle adjacent to the PLE, and inhibition of its activity led to loss, or severe reduction, of FoxE3 expression followed by failure of placode formation. Ectopic activation of Notch signaling induced FoxE3 expression within head ectoderm expressing Otx2, and additional misexpression of Otx2 in trunk ectoderm extended the Notch-induced FoxE3 expression posteriorly. These data provide the first direct evidence of the involvement of Notch signaling in lens induction. The obligate integration of inputs of a field-selector (Otx2) and localized signaling (Notch) within target cis-regulatory elements might be a general mechanism of organ-field specification in vertebrates (as it is in Drosophila). This concept is also consistent with classical embryological studies of many organ systems involving a ;multiple-step induction'.

  11. Patient-Specific Electric Field Simulations and Acceleration Measurements for Objective Analysis of Intraoperative Stimulation Tests in the Thalamus.

    PubMed

    Hemm, Simone; Pison, Daniela; Alonso, Fabiola; Shah, Ashesh; Coste, Jérôme; Lemaire, Jean-Jacques; Wårdell, Karin

    2016-01-01

    Despite an increasing use of deep brain stimulation (DBS) the fundamental mechanisms of action remain largely unknown. Simulation of electric entities has previously been proposed for chronic DBS combined with subjective symptom evaluations, but not for intraoperative stimulation tests. The present paper introduces a method for an objective exploitation of intraoperative stimulation test data to identify the optimal implant position of the chronic DBS lead by relating the electric field (EF) simulations to the patient-specific anatomy and the clinical effects quantified by accelerometry. To illustrate the feasibility of this approach, it was applied to five patients with essential tremor bilaterally implanted in the ventral intermediate nucleus (VIM). The VIM and its neighborhood structures were preoperatively outlined in 3D on white matter attenuated inversion recovery MR images. Quantitative intraoperative clinical assessments were performed using accelerometry. EF simulations (n = 272) for intraoperative stimulation test data performed along two trajectories per side were set-up using the finite element method for 143 stimulation test positions. The resulting EF isosurface of 0.2 V/mm was superimposed to the outlined anatomical structures. The percentage of volume of each structure's overlap was calculated and related to the corresponding clinical improvement. The proposed concept has been successfully applied to the five patients. For higher clinical improvements, not only the VIM but as well other neighboring structures were covered by the EF isosurfaces. The percentage of the volumes of the VIM, of the nucleus intermediate lateral of the thalamus and the prelemniscal radiations within the prerubral field of Forel increased for clinical improvements higher than 50% compared to improvements lower than 50%. The presented new concept allows a detailed and objective analysis of a high amount of intraoperative data to identify the optimal stimulation target. First

  12. Sport- and sample-specific features of trace elements in adolescent female field hockey players and fencers.

    PubMed

    Nabatov, Alexey A; Troegubova, Natalya A; Gilmutdinov, Ruslan R; Sereda, Andrey P; Samoilov, Alexander S; Rylova, Natalya V

    2017-09-01

    Active physical exercises and growth are associated with mineral imbalances in young athletes. The purpose of this study was to examine the impact of sport-related factors on tissue mineral status in adolescent female athletes. Saliva and hair samples were used for the analysis of immediate and more permanent tissue mineral status, respectively. Samples taken from a control non-athletic female group and two groups of female athletes (field hockey and fencing) were analyzed for seven essential minerals: calcium, chromium, iron, potassium, magnesium, selenium and zinc. Inductively-coupled plasma mass spectrometry was used for the quantification of elements having very low concentration range in samples (Se, Cr and Zn) whereas inductively coupled plasma optical emission spectrometry was used for quantification of more ubiquitous elements (Mg, К, Са, Fe). The obtained results for athletic groups were compared with control. Female athletes had increased levels of selenium in both saliva and hair as well as chromium in saliva. Field hockey players had the higher level of zinc in hair whereas fencers had the lower levels of salivary calcium. Strong negative correlation between potassium levels in saliva and hair was identified. Iron and magnesium did not differ between the studied groups. In conclusion, novel sport-specific features of chromium tissue levels in female athletes were found. The studied sport disciplines have different impact on the distribution of osteoporosis-related minerals (calcium and zinc). Our finding can help in the development of osteoporosis preventive trainings and in the proper nutrient supplementation to correct mineral imbalances in female athletes. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Convergence of a head-field selector Otx2 and Notch signaling: a mechanism for lens specification

    PubMed Central

    Ogino, Hajime; Fisher, Marilyn; Grainger, Robert M.

    2014-01-01

    Summary Xenopus is ideal for systematic decoding of cis-regulatory networks because its evolutionary position among vertebrates allows one to combine comparative genomics with efficient transgenic technology in one system. Here we have identified and analyzed the major enhancer of FoxE3/Lens1, a gene essential for lens formation that is activated in the presumptive lens ectoderm (PLE) when commitment to the lens fate occurs. Deletion and mutation analyses of the enhancer based on comparison of Xenopus-mammalian sequences and in vitro and in vivo binding assays identified two essential transcriptional regulators; Otx2, a homeodomain protein expressed broadly in head ectoderm including the PLE, and Su(H), a nuclear signal transducer of Notch signaling. A Notch ligand, Delta2, is expressed in the optic vesicle adjacent to the PLE, and inhibition of its activity led to loss or severe reduction of FoxE3 expression followed by failure of placode formation. Ectopic activation of Notch signaling induced FoxE3 expression within head ectoderm expressing Otx2, and additional misexpression of Otx2 in trunk ectoderm extended the Notch-induced FoxE3 expression posteriorly. These data provide the first direct evidence of involvementof Notch signaling in lens induction. The obligate integration of inputs of a field-selector (Otx2) and localized signaling (Notch) within target cis-regulatory elements may be a general mechanism of organ-field specification in vertebrates (as in Drosophila). This concept is also consistent with classical embryological studies of many organ systems involving a “multiple-step induction”. PMID:18057103

  14. Transcriptome and metabolome profiling of field-grown transgenic barley lack induced differences but show cultivar-specific variances.

    PubMed

    Kogel, Karl-Heinz; Voll, Lars M; Schäfer, Patrick; Jansen, Carin; Wu, Yongchun; Langen, Gregor; Imani, Jafargholi; Hofmann, Jörg; Schmiedl, Alfred; Sonnewald, Sophia; von Wettstein, Diter; Cook, R James; Sonnewald, Uwe

    2010-04-06

    The aim of the present study was to assess possible adverse effects of transgene expression in leaves of field-grown barley relative to the influence of genetic background and the effect of plant interaction with arbuscular mycorrhizal fungi. We conducted transcript profiling, metabolome profiling, and metabolic fingerprinting of wild-type accessions and barley transgenics with seed-specific expression of (1,3-1, 4)-beta-glucanase (GluB) in Baronesse (B) as well as of transgenics in Golden Promise (GP) background with ubiquitous expression of codon-optimized Trichoderma harzianum endochitinase (ChGP). We found more than 1,600 differential transcripts between varieties GP and B, with defense genes being strongly overrepresented in B, indicating a divergent response to subclinical pathogen challenge in the field. In contrast, no statistically significant differences between ChGP and GP could be detected based on transcriptome or metabolome analysis, although 22 genes and 4 metabolites were differentially abundant when comparing GluB and B, leading to the distinction of these two genotypes in principle component analysis. The coregulation of most of these genes in GluB and GP, as well as simple sequence repeat-marker analysis, suggests that the distinctive alleles in GluB are inherited from GP. Thus, the effect of the two investigated transgenes on the global transcript profile is substantially lower than the effect of a minor number of alleles that differ as a consequence of crop breeding. Exposing roots to the spores of the mycorrhizal Glomus sp. had little effect on the leaf transcriptome, but central leaf metabolism was consistently altered in all genotypes.

  15. Field surveys reveal the presence of anti-androgens in an effluent-receiving river using stickleback-specific biomarkers.

    PubMed

    Katsiadaki, Ioanna; Sanders, Matthew B; Henrys, Peter A; Scott, Alexander P; Matthiessen, Peter; Pottinger, Tom G

    2012-10-15

    This study was designed to assess whether the removal of endocrine disrupting chemicals (EDCs) and other substances from a Waste Water Treatment Works (WWTW) effluent (receiving water: R. Ray, Swindon, UK) by granular activated carbon (GAC) affected biomarkers of exposure to EDCs [vitellogenin (VTG) and spiggin] in male and female three-spined sticklebacks in the receiving water. A nearby river (R. Ock), with a negligible effluent loading, was used as a control. On each river fish were sampled from four sites on five occasions both before and after remediation of the WWTW effluent. The results show for the first time in a UK field study a clear seasonality of blood VTG concentrations in wild male fish, following closely the VTG profile in female fish from both rivers. VTG levels in male fish from the R. Ray were significantly reduced after the GAC installation. However, VTG levels in males from the control sites also varied significantly across the same period, reducing the significance of this finding. A laboratory exposure to oestradiol (using site-specific lower and upper levels of oestrogenic activity) failed to elevate VTG concentrations in male sticklebacks suggesting that concentrations in the effluent, even prior to remediation, may not have exceeded a critical sensitivity threshold. Most importantly, a significant increase in female kidney spiggin content (a highly specific biomarker of xeno-androgen exposure) occurred in fish in the R. Ray after the GAC installation to levels comparable with those in fish from the control river. The significance of this finding is strengthened by the fact that during the pre-remediation period in the R. Ray, female spiggin levels increased with increasing distance from the WWTW. Our results provide the first in vivo evidence of the presence of anti-androgens in a UK WWTW effluent. To our knowledge this is the first UK-based comprehensive field study on the effects of a WWTW upgrade on biomarkers of EDC exposure using a

  16. Endogenous expression of ASLV viral proteins in specific pathogen free chicken embryos: relevance for the developmental biology research field

    PubMed Central

    2010-01-01

    Background The use of Specific Pathogen Free (SPF) eggs in combination with RCAS retrovirus, a member of the Avian Sarcoma-Leukosis Virus (ASLV) family, is of standard practice to study gene function and development. SPF eggs are certified free of infection by specific pathogen viruses of either exogenous or endogenous origin, including those belonging to the ASLV family. Based on this, SPF embryos are considered to be free of ASLV viral protein expression, and consequently in developmental research studies RCAS infected cells are routinely identified by immunohistochemistry against the ASLV viral proteins p19 and p27. Contrary to this generally accepted notion, observations in our laboratory suggested that certified SPF chicken embryos may endogenously express ASLV viral proteins p19 and p27. Since these observations may have significant implications for the developmental research field we further investigated this possibility. Results We demonstrate that certified SPF chicken embryos have transcriptionally active endogenous ASLV loci (ev loci) capable of expressing ASLV viral proteins, such as p19 and p27, even when those loci are not capable of producing viral particles. We also show that the extent of viral protein expression in embryonic tissues varies not only among flocks but also between embryos of the same flock. In addition, our genetic screening revealed significant heterogeneity in ev loci composition even among embryos of the same flock. Conclusions These observations have critical implications for the developmental biology research field, since they strongly suggest that the current standard methodology used in experimental studies using the chick embryo and RCAS vectors may lead to inaccurate interpretation of results. Retrospectively, our observations suggest that studies in which infected cells have been identified simply by pan-ASLV viral protein expression may need to be considered with caution. For future studies, they point to a need for

  17. Endogenous expression of ASLV viral proteins in specific pathogen free chicken embryos: relevance for the developmental biology research field.

    PubMed

    McNally, Minda M; Wahlin, Karl J; Canto-Soler, M Valeria

    2010-10-18

    The use of Specific Pathogen Free (SPF) eggs in combination with RCAS retrovirus, a member of the Avian Sarcoma-Leukosis Virus (ASLV) family, is of standard practice to study gene function and development. SPF eggs are certified free of infection by specific pathogen viruses of either exogenous or endogenous origin, including those belonging to the ASLV family. Based on this, SPF embryos are considered to be free of ASLV viral protein expression, and consequently in developmental research studies RCAS infected cells are routinely identified by immunohistochemistry against the ASLV viral proteins p19 and p27. Contrary to this generally accepted notion, observations in our laboratory suggested that certified SPF chicken embryos may endogenously express ASLV viral proteins p19 and p27. Since these observations may have significant implications for the developmental research field we further investigated this possibility. We demonstrate that certified SPF chicken embryos have transcriptionally active endogenous ASLV loci (ev loci) capable of expressing ASLV viral proteins, such as p19 and p27, even when those loci are not capable of producing viral particles. We also show that the extent of viral protein expression in embryonic tissues varies not only among flocks but also between embryos of the same flock. In addition, our genetic screening revealed significant heterogeneity in ev loci composition even among embryos of the same flock. These observations have critical implications for the developmental biology research field, since they strongly suggest that the current standard methodology used in experimental studies using the chick embryo and RCAS vectors may lead to inaccurate interpretation of results. Retrospectively, our observations suggest that studies in which infected cells have been identified simply by pan-ASLV viral protein expression may need to be considered with caution. For future studies, they point to a need for careful selection and screening of

  18. Subject-specific modulation of local field potential spectral power during brain-machine interface control in primates

    NASA Astrophysics Data System (ADS)

    So, Kelvin; Dangi, Siddharth; Orsborn, Amy L.; Gastpar, Michael C.; Carmena, Jose M.

    2014-04-01

    Objective. Intracortical brain-machine interfaces (BMIs) have predominantly utilized spike activity as the control signal. However, an increasing number of studies have shown the utility of local field potentials (LFPs) for decoding motor related signals. Currently, it is unclear how well different LFP frequencies can serve as features for continuous, closed-loop BMI control. Approach. We demonstrate 2D continuous LFP-based BMI control using closed-loop decoder adaptation, which adapts decoder parameters to subject-specific LFP feature modulations during BMI control. We trained two macaque monkeys to control a 2D cursor in a center-out task by modulating LFP power in the 0-150 Hz range. Main results. While both monkeys attained control, they used different strategies involving different frequency bands. One monkey primarily utilized the low-frequency spectrum (0-80 Hz), which was highly correlated between channels, and obtained proficient performance even with a single channel. In contrast, the other monkey relied more on higher frequencies (80-150 Hz), which were less correlated between channels, and had greater difficulty with control as the number of channels decreased. We then restricted the monkeys to use only various sub-ranges (0-40, 40-80, and 80-150 Hz) of the 0-150 Hz band. Interestingly, although both monkeys performed better with some sub-ranges than others, they were able to achieve BMI control with all sub-ranges after decoder adaptation, demonstrating broad flexibility in the frequencies that could potentially be used for LFP-based BMI control. Significance. Overall, our results demonstrate proficient, continuous BMI control using LFPs and provide insight into the subject-specific spectral patterns of LFP activity modulated during control.

  19. Sensitivity and specificity considerations for fMRI encoding, decoding, and mapping of auditory cortex at ultra-high field.

    PubMed

    Moerel, Michelle; De Martino, Federico; Kemper, Valentin G; Schmitter, Sebastian; Vu, An T; Uğurbil, Kâmil; Formisano, Elia; Yacoub, Essa

    2017-03-31

    Following rapid technological advances, ultra-high field functional MRI (fMRI) enables exploring correlates of neuronal population activity at an increasing spatial resolution. However, as the fMRI blood-oxygenation-level-dependent (BOLD) contrast is a vascular signal, the spatial specificity of fMRI data is ultimately determined by the characteristics of the underlying vasculature. At 7T, fMRI measurement parameters determine the relative contribution of the macro- and microvasculature to the acquired signal. Here we investigate how these parameters affect relevant high-end fMRI analyses such as encoding, decoding, and submillimeter mapping of voxel preferences in the human auditory cortex. Specifically, we compare a T2* weighted fMRI dataset, obtained with 2D gradient echo (GE) EPI, to a predominantly T2 weighted dataset obtained with 3D GRASE. We first investigated the decoding accuracy based on two encoding models that represented different hypotheses about auditory cortical processing. This encoding/decoding analysis profited from the large spatial coverage and sensitivity of the T2* weighted acquisitions, as evidenced by a significantly higher prediction accuracy in the GE-EPI dataset compared to the 3D GRASE dataset for both encoding models. The main disadvantage of the T2* weighted GE-EPI dataset for encoding/decoding analyses was that the prediction accuracy exhibited cortical depth dependent vascular biases. However, we propose that the comparison of prediction accuracy across the different encoding models may be used as a post processing technique to salvage the spatial interpretability of the GE-EPI cortical depth-dependent prediction accuracy. Second, we explored the mapping of voxel preferences. Large-scale maps of frequency preference (i.e., tonotopy) were similar across datasets, yet the GE-EPI dataset was preferable due to its larger spatial coverage and sensitivity. However, submillimeter tonotopy maps revealed biases in assigned frequency

  20. Sex-specific life history responses to nymphal diet quality and immune status in a field cricket.

    PubMed

    Kelly, C D; Neyer, A A; Gress, B E

    2014-02-01

    Individual fitness is expected to benefit from earlier maturation at a larger body size and higher body condition. However, poor nutritional quality or high prevalence of disease make this difficult because individuals either cannot acquire sufficient resources or must divert resources to other fitness-related traits such as immunity. Under such conditions, individuals are expected to mature later at a smaller body size and in poorer body condition. Moreover, the juvenile environment can also produce longer-term effects on adult fitness by causing shifts in resource allocation strategies that could alter investment in immune function and affect adult lifespan. We manipulated diet quality and immune status of juvenile Texas field crickets, Gryllus texensis, to investigate how poor developmental conditions affect sex-specific investment in fitness-related traits. As predicted, a poor juvenile diet was related to smaller mass and body size at eclosion in both sexes. However, our results also reveal sexually dimorphic responses to different facets of the rearing environment: female life history decisions are affected more by diet quality, whereas males are affected more by immune status. We suggest that females respond to decreased nutritional income because this threatens their ability to achieve a large adult body size, whereas male fitness is more dependent on reaching adulthood and so they invest in immunity and survival to eclosion.

  1. Wireless hippocampal neural recording via a multiple input RF receiver to construct place-specific firing fields.

    PubMed

    Lee, Seung Bae; Manns, Joseph R; Ghovanloo, Maysam

    2012-01-01

    This paper reports scientifically meaningful in vivo experiments using a 32-channel wireless neural recording system (WINeR). The WINeR system is divided into transmitter (Tx) and receiver (Rx) parts. On the Tx side, we had WINeR-6, a system-on-a-chip (SoC) that operated based on time division multiplexing (TDM) of pulse width modulated (PWM) samples. The chip was fabricated in a 0.5-µm CMOS process, occupying 4.9 × 3.3 mm(2) and consuming 15 mW from ±1.5V supplies. The Rx used two antennas with separate pathways to down-convert the RF signal from a large area. A time-to-digital converter (TDC) in an FPGA converted the PWM pulses into digitized samples. In order to further increase the wireless coverage area and eliminate blind spots within a large experimental arena, two receivers were synchronized. The WINeR system was used to record epileptic activities from a rat that was injected with tetanus toxin (TT) in the dorsal hippocampus. In a different in vivo experiment, place-specific firing fields of place cells, which are parts of the hippocampal-dependent memory, were mapped from a series of behavioral experiments from a rat running in a circular track. Results from the same animal were compared against a commercial hard-wired recording system to evaluate the quality of the wireless recordings.

  2. Patient-Specific Electric Field Simulations and Acceleration Measurements for Objective Analysis of Intraoperative Stimulation Tests in the Thalamus

    PubMed Central

    Hemm, Simone; Pison, Daniela; Alonso, Fabiola; Shah, Ashesh; Coste, Jérôme; Lemaire, Jean-Jacques; Wårdell, Karin

    2016-01-01

    Despite an increasing use of deep brain stimulation (DBS) the fundamental mechanisms of action remain largely unknown. Simulation of electric entities has previously been proposed for chronic DBS combined with subjective symptom evaluations, but not for intraoperative stimulation tests. The present paper introduces a method for an objective exploitation of intraoperative stimulation test data to identify the optimal implant position of the chronic DBS lead by relating the electric field (EF) simulations to the patient-specific anatomy and the clinical effects quantified by accelerometry. To illustrate the feasibility of this approach, it was applied to five patients with essential tremor bilaterally implanted in the ventral intermediate nucleus (VIM). The VIM and its neighborhood structures were preoperatively outlined in 3D on white matter attenuated inversion recovery MR images. Quantitative intraoperative clinical assessments were performed using accelerometry. EF simulations (n = 272) for intraoperative stimulation test data performed along two trajectories per side were set-up using the finite element method for 143 stimulation test positions. The resulting EF isosurface of 0.2 V/mm was superimposed to the outlined anatomical structures. The percentage of volume of each structure’s overlap was calculated and related to the corresponding clinical improvement. The proposed concept has been successfully applied to the five patients. For higher clinical improvements, not only the VIM but as well other neighboring structures were covered by the EF isosurfaces. The percentage of the volumes of the VIM, of the nucleus intermediate lateral of the thalamus and the prelemniscal radiations within the prerubral field of Forel increased for clinical improvements higher than 50% compared to improvements lower than 50%. The presented new concept allows a detailed and objective analysis of a high amount of intraoperative data to identify the optimal stimulation target

  3. Zebrafish second heart field development relies on progenitor specification in anterior lateral plate mesoderm and nkx2.5 function.

    PubMed

    Guner-Ataman, Burcu; Paffett-Lugassy, Noelle; Adams, Meghan S; Nevis, Kathleen R; Jahangiri, Leila; Obregon, Pablo; Kikuchi, Kazu; Poss, Kenneth D; Burns, Caroline E; Burns, C Geoffrey

    2013-03-01

    Second heart field (SHF) progenitors perform essential functions during mammalian cardiogenesis. We recently identified a population of cardiac progenitor cells (CPCs) in zebrafish expressing latent TGFβ-binding protein 3 (ltbp3) that exhibits several defining characteristics of the anterior SHF in mammals. However, ltbp3 transcripts are conspicuously absent in anterior lateral plate mesoderm (ALPM), where SHF progenitors are specified in higher vertebrates. Instead, ltbp3 expression initiates at the arterial pole of the developing heart tube. Because the mechanisms of cardiac development are conserved evolutionarily, we hypothesized that zebrafish SHF specification also occurs in the ALPM. To test this hypothesis, we Cre/loxP lineage traced gata4(+) and nkx2.5(+) ALPM populations predicted to contain SHF progenitors, based on evolutionary conservation of ALPM patterning. Traced cells were identified in SHF-derived distal ventricular myocardium and in three lineages in the outflow tract (OFT). We confirmed the extent of contributions made by ALPM nkx2.5(+) cells using Kaede photoconversion. Taken together, these data demonstrate that, as in higher vertebrates, zebrafish SHF progenitors are specified within the ALPM and express nkx2.5. Furthermore, we tested the hypothesis that Nkx2.5 plays a conserved and essential role during zebrafish SHF development. Embryos injected with an nkx2.5 morpholino exhibited SHF phenotypes caused by compromised progenitor cell proliferation. Co-injecting low doses of nkx2.5 and ltbp3 morpholinos revealed a genetic interaction between these factors. Taken together, our data highlight two conserved features of zebrafish SHF development, reveal a novel genetic relationship between nkx2.5 and ltbp3, and underscore the utility of this model organism for deciphering SHF biology.

  4. Zebrafish second heart field development relies on progenitor specification in anterior lateral plate mesoderm and nkx2.5 function

    PubMed Central

    Guner-Ataman, Burcu; Paffett-Lugassy, Noelle; Adams, Meghan S.; Nevis, Kathleen R.; Jahangiri, Leila; Obregon, Pablo; Kikuchi, Kazu; Poss, Kenneth D.; Burns, Caroline E.; Burns, C. Geoffrey

    2013-01-01

    Second heart field (SHF) progenitors perform essential functions during mammalian cardiogenesis. We recently identified a population of cardiac progenitor cells (CPCs) in zebrafish expressing latent TGFβ-binding protein 3 (ltbp3) that exhibits several defining characteristics of the anterior SHF in mammals. However, ltbp3 transcripts are conspicuously absent in anterior lateral plate mesoderm (ALPM), where SHF progenitors are specified in higher vertebrates. Instead, ltbp3 expression initiates at the arterial pole of the developing heart tube. Because the mechanisms of cardiac development are conserved evolutionarily, we hypothesized that zebrafish SHF specification also occurs in the ALPM. To test this hypothesis, we Cre/loxP lineage traced gata4+ and nkx2.5+ ALPM populations predicted to contain SHF progenitors, based on evolutionary conservation of ALPM patterning. Traced cells were identified in SHF-derived distal ventricular myocardium and in three lineages in the outflow tract (OFT). We confirmed the extent of contributions made by ALPM nkx2.5+ cells using Kaede photoconversion. Taken together, these data demonstrate that, as in higher vertebrates, zebrafish SHF progenitors are specified within the ALPM and express nkx2.5. Furthermore, we tested the hypothesis that Nkx2.5 plays a conserved and essential role during zebrafish SHF development. Embryos injected with an nkx2.5 morpholino exhibited SHF phenotypes caused by compromised progenitor cell proliferation. Co-injecting low doses of nkx2.5 and ltbp3 morpholinos revealed a genetic interaction between these factors. Taken together, our data highlight two conserved features of zebrafish SHF development, reveal a novel genetic relationship between nkx2.5 and ltbp3, and underscore the utility of this model organism for deciphering SHF biology. PMID:23444361

  5. Mapping 3D breast lesions from full-field digital mammograms using subject-specific finite element models

    NASA Astrophysics Data System (ADS)

    García, E.; Oliver, A.; Diaz, O.; Diez, Y.; Gubern-Mérida, A.; Martí, R.; Martí, J.

    2017-03-01

    Patient-specific finite element (FE) models of the breast have received increasing attention due to the potential capability of fusing images from different modalities. During the Magnetic Resonance Imaging (MRI) to X-ray mammography registration procedure, the FE model is compressed mimicking the mammographic acquisition. Subsequently, suspicious lesions in the MRI volume can be projected into the 2D mammographic space. However, most registration algorithms do not provide the reverse information, avoiding to obtain the 3D geometrical information from the lesions localized in the mammograms. In this work we introduce a fast method to localize the 3D position of the lesion within the MRI, using both cranio-caudal (CC) and medio-lateral oblique (MLO) mammographic projections, indexing the tetrahedral elements of the biomechanical model by means of an uniform grid. For each marked lesion in the Full-Field Digital Mammogram (FFDM), the X-ray path from source to the marker is calculated. Barycentric coordinates are computed in the tetrahedrons traversed by the ray. The list of elements and coordinates allows to localize two curves within the MRI and the closest point between both curves is taken as the 3D position of the lesion. The registration errors obtained in the mammographic space are 9.89 +/- 3.72 mm in CC- and 8.04 +/- 4.68 mm in MLO-projection and the error in the 3D MRI space is equal to 10.29 +/- 3.99 mm. Regarding the uniform grid, it is computed spending between 0.1 and 0.7 seconds. The average time spent to compute the 3D location of a lesion is about 8 ms.

  6. Specific-Heat of High-Temperature Superconductors: Apparatus and Measurements (magnetic Field, Yttrium Barium Copper Oxide, Mercury Barium Copper Oxide, Barium Potassium Bismuth Oxide.

    NASA Astrophysics Data System (ADS)

    Woodfield, Brian Fred

    1995-01-01

    An apparatus has been designed and constructed capable of measuring the specific heat from 0.6 K to 130 K using a variety of specific-heat techniques in magnetic fields as high as 9 T. The apparatus contains a temperature -controlled block with reference thermometers shielded from the magnetic field to allow precise calibrations of the working thermometers in a magnetic field. Currently, the apparatus is configured for specific-heat measurements on 1 to 3 g samples using the semi-adiabatic pulse and continuous heating methods. Specific-heat results on copper show the accuracy of the measurements to be better than +/-0.25% for temperatures less than 40 K but reaches 1.5% at 130 K. The reproducibility of the measurements is generally better than +/- 0.15%, and the in-field specific-heat results agree with the zero-field results to within +/- 0.25%. The specific heat has been measured on the high -temperature superconductors rm YBa_2Cu _3O_{7-delta}, HgBa _2CuO_{4+delta}, and Ba_{1-x}K_{x}BiO _3. The results of the rm YBa_2Cu_3O_{7-delta} measurements demonstrate the equality of the entropies in the low-temperature zero-field upturn and the in-field Schottky anomalies. For rm HgBa_2CuO _{4+delta} a specific heat anomaly at T_{c}~95 K is consistent with bulk superconductivity and an estimate of the electron density of states. The results on a rm Ba_{1-x}K_ {x}BiO_3 sample with x = 0.4 shows a transition temperature of 30 K and for a sample with x = 0.47, a transition temperature of 19 K. Measurements in a magnetic field for the x = 0.4 and x = 0.47 samples gives a measure of the normal-state electron density of states. The absence of a linear term in zero-field for both samples shows the samples were fully superconducting.

  7. Magnetic field dependence of the magnetic susceptibility and the specific heat of the doped plasticized polyaniline (PANI-DB3EPSA)0.5.

    PubMed

    Djurado, D; Pron, A; Jacquot, J F; Travers, J P; Adriano, C; Vargas, J M; Pagliuso, P G; Rettori, C; Lesseux, G G; Fier, I; Walmsley, L

    2011-05-25

    Specific heat, magnetization and electron spin resonance (ESR) data obtained from a self-standing film of the doped plasticized polyaniline (PANI-DB3EPSA)(0.5) are shown. No long range magnetic order has been observed at zero magnetic field, above 2 K. For a magnetic field of 3.3 kOe applied perpendicular to the plane of the film, a clear signature of an induced ordered state can be seen in the specific heat data and ESR also reveals this antiferromagnetic order. An electronic contribution is detected from ESR, magnetization and specific heat; however, for T ≤ 5 K, the specific heat data show the existence of a gap. Magnetization data also show a low temperature dominant Curie behaviour which cannot be seen from ESR, probably due to a very large linewidth, suggesting short range correlations among spin 1/2 polarons.

  8. A new compact neutron/gamma ray scintillation detector

    NASA Astrophysics Data System (ADS)

    Buffler, A.; Comrie, A. C.; Smit, F. D.; Wörtche, H. J.

    2016-09-01

    Progress towards the realization of a new compact neutron spectrometer is described. The detector is based on EJ299-33 plastic scintillator coupled to silicon photomultipliers, and a digital implementation of pulse shape discrimination is used to separate events associated with neutrons from those associated with gamma rays. The spectrometer will be suitable over the neutron energy range 1-100 MeV, illustrated in this work with measurements made using an AmBe radioisotopic source and quasi-monoenergetic neutron beams produced using a cyclotron.

  9. Neutron-$$\\gamma$$ competition for β-delayed neutron emission

    DOE PAGES

    Mumpower, Matthew Ryan; Kawano, Toshihiko; Moller, Peter

    2016-12-19

    Here we present a coupled quasiparticle random phase approximation and Hauser-Feshbach (QRPA+HF) model for calculating delayed particle emission. This approach uses microscopic nuclear structure information, which starts with Gamow-Teller strength distributions in the daughter nucleus and then follows the statistical decay until the initial available excitation energy is exhausted. Explicitly included at each particle emission stage is γ-ray competition. We explore this model in the context of neutron emission of neutron-rich nuclei and find that neutron-γ competition can lead to both increases and decreases in neutron emission probabilities, depending on the system considered. Finally, a second consequence of this formalismmore » is a prediction of more neutrons on average being emitted after β decay for nuclei near the neutron drip line compared to models that do not consider the statistical decay.« less

  10. Neutron-$\\gamma$ competition for β-delayed neutron emission

    SciTech Connect

    Mumpower, Matthew Ryan; Kawano, Toshihiko; Moller, Peter

    2016-12-19

    Here we present a coupled quasiparticle random phase approximation and Hauser-Feshbach (QRPA+HF) model for calculating delayed particle emission. This approach uses microscopic nuclear structure information, which starts with Gamow-Teller strength distributions in the daughter nucleus and then follows the statistical decay until the initial available excitation energy is exhausted. Explicitly included at each particle emission stage is γ-ray competition. We explore this model in the context of neutron emission of neutron-rich nuclei and find that neutron-γ competition can lead to both increases and decreases in neutron emission probabilities, depending on the system considered. Finally, a second consequence of this formalism is a prediction of more neutrons on average being emitted after β decay for nuclei near the neutron drip line compared to models that do not consider the statistical decay.

  11. Large-Animal Neutron-Gamma Irradiation Experiment.

    DTIC Science & Technology

    1958-05-01

    Eighty-eight burros were exposed to prompt neutron and gamma radiation from a nuclear detonation. Shielded from heat and missiles the animals were...determine the median lethality response of the burro to the radiation described; (2) normalize the effect in the burro to that in the monkey; (3) compare

  12. Analysis of in situ electric field and specific absorption rate in human models for wireless power transfer system with induction coupling

    NASA Astrophysics Data System (ADS)

    Sunohara, Tetsu; Hirata, Akimasa; Laakso, Ilkka; Onishi, Teruo

    2014-07-01

    This study investigates the specific absorption rate (SAR) and the in situ electric field in anatomically based human models for the magnetic field from an inductive wireless power transfer system developed on the basis of the specifications of the wireless power consortium. The transfer system consists of two induction coils covered by magnetic sheets. Both the waiting and charging conditions are considered. The transfer frequency considered in this study is 140 kHz, which is within the range where the magneto-quasi-static approximation is valid. The SAR and in situ electric field in the chest and arm of the models are calculated by numerically solving the scalar potential finite difference equation. The electromagnetic modelling of the coils in the wireless power transfer system is verified by comparing the computed and measured magnetic field distributions. The results indicate that the peak value of the SAR averaged over a 10 g of tissue and that of the in situ electric field are 72 nW kg-1 and 91 mV m-1 for a transmitted power of 1 W, Consequently, the maximum allowable transmitted powers satisfying the exposure limits of the SAR (2 W kg-1) and the in situ electric field (18.9 V m-1) are found to be 28 MW and 43 kW. The computational results show that the in situ electric field in the chest is the most restrictive factor when compliance with the wireless power transfer system is evaluated according to international guidelines.

  13. A method to measure specific absorption rate of nanoparticles in colloidal suspension using different configurations of radio-frequency fields.

    PubMed

    Ketharnath, Dhivya; Pande, Rohit; Xie, Leiming; Srinivasan, Srimeenakshi; Godin, Biana; Wosik, Jarek

    2012-08-20

    We report a method for characterization of the efficiency of radio-frequency (rf) heating of nanoparticles (NPs) suspended in an aqueous medium. Measurements were carried out for water suspended 5 nm superparamagnetic iron-oxide NPs with 30 nm dextran matrix for three different configurations of rf electric and magnetic fields. A 30 MHz high-Q resonator was designed to measure samples placed inside a parallel plate capacitor and solenoid coil with or without an rf electric field shield. All components of rf losses were analyzed and rf electric and magnetic field induced heating of NPs and the dispersion medium was determined and discussed.

  14. Muscle co-contraction patterns in robot-mediated force field learning to guide specific muscle group training.

    PubMed

    Pizzamiglio, Sara; Desowska, Adela; Shojaii, Pegah; Taga, Myriam; Turner, Duncan L

    2017-01-01

    Muscle co-contraction is a strategy of increasing movement accuracy and stability employed in dealing with force perturbation of movement. It is often seen in neuropathological populations. The direction of movement influences the pattern of co-contraction, but not all movements are easily achievable for populations with motor deficits. Manipulating the direction of the force instead, may be a promising rehabilitation protocol to train movement with use of a co-contraction reduction strategy. Force field learning paradigms provide a well described procedure to evoke and test muscle co-contraction. The aim of this study was to test the muscle co-contraction pattern in a wide range of arm muscles in different force-field directions utilising a robot-mediated force field learning paradigm of motor adaptation. Forty-two participants volunteered to participate in a study utilising robot-mediated force field motor adaptation paradigm with a clockwise or counter-clockwise force field. Kinematics and surface electromyography (EMG) of eight arm muscles were measured. Both muscle activation and co-contraction was earlier and stronger in flexors in the clockwise condition and in extensors in the counter-clockwise condition. Manipulating the force field direction leads to changes in the pattern of muscle co-contraction.

  15. The Influence of Current Density and Magnetic Field Topography in Optimizing the Performance, Divergence, and Plasma Oscillations of High Specific Impulse Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Hofer, Richard R.; Jankovsky, Robert S.

    2003-01-01

    Recent studies of xenon Hall thrusters have shown peak efficiencies at specific impulses of less than 3000 s. This was a consequence of modern Hall thruster magnetic field topographies, which have been optimized for 300 V discharges. On-going research at the NASA Glenn Research Center is investigating this behavior and methods to enhance thruster performance. To conduct these studies, a laboratory model Hall thruster that uses a pair of trim coils to tailor the magnetic field topography for high specific impulse operation has been developed. The thruster-the NASA-173Mv2 was tested to determine how current density and magnetic field topography affect performance, divergence, and plasma oscillations at voltages up to 1000 V. Test results showed there was a minimum current density and optimum magnetic field topography at which efficiency monotonically increased with voltage. At 1000 V, 10 milligrams per second the total specific impulse was 3390 s and the total efficiency was 60.8%. Plume divergence decreased at 400-1000 V, but increased at 300-400 V as the result of plasma oscillations. The dominant oscillation frequency steadily increased with voltage, from 14.5 kHz at 300 V, to 22 kHz at 1000 V. An additional oscillatory mode in the 80-90 kHz frequency range began to appear above 500 V. The use of trim coils to modify the magnetic field improved performance while decreasing plume divergence and the frequency and magnitude of plasma oscillations.

  16. A sensitive, specific and reproducible real-time polymerase chain reaction method for detection of Plasmodium vivax and Plasmodium falciparum infection in field-collected anophelines.

    PubMed

    Bickersmith, Sara A; Lainhart, William; Moreno, Marta; Chu, Virginia M; Vinetz, Joseph M; Conn, Jan E

    2015-06-01

    We describe a simple method for detection of Plasmodium vivax and Plasmodium falciparum infection in anophelines using a triplex TaqMan real-time polymerase chain reaction (PCR) assay (18S rRNA). We tested the assay on Anopheles darlingi and Anopheles stephensi colony mosquitoes fed with Plasmodium-infected blood meals and in duplicate on field collected An. darlingi. We compared the real-time PCR results of colony-infected and field collected An. darlingi, separately, to a conventional PCR method. We determined that a cytochrome b-PCR method was only 3.33% as sensitive and 93.38% as specific as our real-time PCR assay with field-collected samples. We demonstrate that this assay is sensitive, specific and reproducible.

  17. Magnetic field induced enlargement of the regime of critical fluctuations in the classical superconductor V3Si from high-resolution specific heat experiments

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Liu, Y.; Toyota, N.; Lortz, R.

    2015-02-01

    We present high-resolution specific heat data from a high-purity single crystal of the classical superconductor V3Si, which reveal tiny lambda-shape anomalies at the superconducting transition superimposed onto the BCS specific heat jump in magnetic fields of 2 T and higher. The appearance of these anomalies is accompanied by a magnetic-field-induced broadening of the superconducting transition. We demonstrate, using scaling relations predicted by the fluctuation models of the 3d-XY and the 3d-lowest-Landau-level (3d-LLL) universality class that the effect of critical fluctuations becomes experimentally observable due to of a magnetic field-induced enlargement of the regime of critical fluctuations. The scaling indicates that a reduction of the effective dimensionality due to the confinement of quasiparticles into low Landau levels is responsible for this effect.

  18. Effects of static magnetic field on specific adenosine-5{prime}-triphosphatase activities and bioelectrical and biomechanical properties in the rat diaphragm muscle

    SciTech Connect

    Itegin, M.; Guenay, I.; Logoglu, G.; Isbir, T.

    1995-08-01

    In this study, the authors aimed to clarify the effects of chronically applied static magnetic field (200 Gauss) on specific ATPase activities and bioelectrical and biomechanical responses in the isolated rat diaphragm muscle. The mean activities of Na{sup +}-K{sup +} ATPase and Ca{sup 2+} ATPase determined from the diaphragm homogenates were significantly higher in the magnetic field exposed group (n = 20), but that of Mg{sup 2+} ATPase was nonsignificantly lower compared to the control group (n = 13). Resting membrane potential, amplitude of muscle action potential, and overshoot values (mean {+-} SE) in the control group were found to be {minus}76.5 {+-} 0.6, 100 {+-} 0.8, and 23.5 {+-} 0.6 mV, respectively; these values were determined to be {minus}72.8 {+-} 0.4, 90.3 {+-} 0.5, and 17.2 {+-} 0.4 mV in the magnetic field-exposed group, respectively. The latency was determined to increase in the experimental group, and all the above-mentioned bioelectrical differences between the groups were significant statistically. Force of muscle twitch was found to decrease significantly in the magnetic field-exposed group, and this finding was attributed to the augmenting effect of magnetic field on Ca{sup 2+} ATPase activity. These results suggest that magnetic field exposure changes specific ATPase activities and, thence, bioelectrical and biomechanical properties in the rat diaphragm muscle.

  19. Stage-Specific Expression of Resistance to Different Acaricides in Four Field Populations of Tetranychus urticae (Acari: Tetranychidae).

    PubMed

    Tang, Xiaofeng; Zhang, Youjun; Wu, Qingjun; Xie, Wen; Wang, Shaoli

    2014-10-01

    The two-spotted spider mite, Tetranychus urticae Koch, is a worldwide crop pest. The resistance to commonly applied acaricides (in this report, "acaricide" refers to both acaricides and insecticides that are toxic to mites) has seriously impaired T. urticae control in the field. Here, the sensitivity of eggs, larvae, and adults of laboratory and field populations of T. urticae to various acaricides was investigated. Based on data obtained with an acaricide-sensitive laboratory strain collected in 2009, abamectin was the most toxic of the tested acaricides. For each acaricide, susceptibility was greatest for larvae, least for adults, and intermediate for eggs. The egg was the most sensitive stage to abamectin, bifenazate, and hexythiazox; the larva was the most sensitive stage to abamectin, hexythiazox, bifenazate, propargite, and chlorfenapyr; and the adult was the most sensitive stage to abamectin, bifenazate, and chlorfenapyr. Based on the results obtained with the acaricide-sensitive laboratory strain, acaricides were selected to test against eggs, larvae, and adults of four field populations of T. urticae from Beijing, China. Although the field populations differed in their resistance to the acaricides in laboratory bioassays, the eggs, larvae, and adults of the four populations were sensitive to bifenazate and highly resistant to abamectin. Field trials for control of T. urticae in Beijing, China, should be conducted with bifenazate and other acaricides rather than with abamectin.

  20. Phylogenomics of Xanthomonas field strains infecting pepper and tomato reveals diversity in effector repertoires and identifies determinants of host specificity

    PubMed Central

    Schwartz, Allison R.; Potnis, Neha; Timilsina, Sujan; Wilson, Mark; Patané, José; Martins, Joaquim; Minsavage, Gerald V.; Dahlbeck, Douglas; Akhunova, Alina; Almeida, Nalvo; Vallad, Gary E.; Barak, Jeri D.; White, Frank F.; Miller, Sally A.; Ritchie, David; Goss, Erica; Bart, Rebecca S.; Setubal, João C.; Jones, Jeffrey B.; Staskawicz, Brian J.

    2015-01-01

    Bacterial spot disease of pepper and tomato is caused by four distinct Xanthomonas species and is a severely limiting factor on fruit yield in these crops. The genetic diversity and the type III effector repertoires of a large sampling of field strains for this disease have yet to be explored on a genomic scale, limiting our understanding of pathogen evolution in an agricultural setting. Genomes of 67 Xanthomonas euvesicatoria (Xe), Xanthomonas perforans (Xp), and Xanthomonas gardneri (Xg) strains isolated from diseased pepper and tomato fields in the southeastern and midwestern United States were sequenced in order to determine the genetic diversity in field strains. Type III effector repertoires were computationally predicted for each strain, and multiple methods of constructing phylogenies were employed to understand better the genetic relationship of strains in the collection. A division in the Xp population was detected based on core genome phylogeny, supporting a model whereby the host-range expansion of Xp field strains on pepper is due, in part, to a loss of the effector AvrBsT. Xp-host compatibility was further studied with the observation that a double deletion of AvrBsT and XopQ allows a host range expansion for Nicotiana benthamiana. Extensive sampling of field strains and an improved understanding of effector content will aid in efforts to design disease resistance strategies targeted against highly conserved core effectors. PMID:26089818

  1. Improving the specificity of R2' to the deoxyhaemoglobin content of brain tissue: Prospective correction of macroscopic magnetic field gradients.

    PubMed

    Blockley, Nicholas P; Stone, Alan J

    2016-07-15

    The reversible transverse relaxation rate, R2', is sensitive to the deoxyhaemoglobin content of brain tissue, enabling information about the oxygen extraction fraction to be obtained. However, R2' is also sensitive to macroscopic magnetic field gradients, particularly at air-tissue interfaces where a large susceptibility difference is present. It is important that this latter effect is minimised in order to produce meaningful estimates of blood oxygenation. Therefore, the aim of this study was to implement a technique to prospectively correct for the effect of susceptibility induced magnetic field gradients on R2' weighted data. This was achieved by combining the Gradient-Echo Slice Excitation Profile Imaging (GESEPI) technique with an Asymmetric Spin Echo (ASE) pulse sequence. The main advantages of this approach are (i) shorter acquisition times, since a separately acquired magnetic field map is not required and (ii) simpler analysis, since retrospective correction for the effects of magnetic field gradients in postprocessing is not required. In these experiments we show that with this newly developed technique it is possible to correct the majority of grey matter voxels for the expected distribution of through-slice magnetic field gradients to produce maps of R2' in a short scan duration.

  2. Therapy of infections in mice irradiated in mixed neutron/photon fields and inflicted with wound trauma: A review of current work. (Reannouncement with new availability information)

    SciTech Connect

    Ledney, G.D.; Madonna, G.S.; Elliott, T.B.; Moore, M.M.; Jackson, W.E.

    1991-12-31

    When host antimicrobial defenses are severely compromised by radiation or trauma in conjunction with radiation, death from sepsis results. To evaluate therapies for sepsis in radiation casualties, the authors developed models of acquired and induced bacterial infections in irradiated and irradiated-wounded mice. Animals were exposed to either a mixed radiation field of equal proportions of neutrons and gamma rays (n/gamma = 1) from a TRIGA reactor or pure gamma rays from 60 (Co sources). Skin wounds (15% of total body surface area) were inflicted under methoxyflurane anesthesia 1 h after irradiation. In all mice, wounding after irradiation decreased resistance to infection. Treatments with the immunomodulator synthetic trehalose dicorynomycolate (S-TDCM) before or after mixed neutron-gamma irradiation or gamma irradiation increased survival. Therapy with S-TDCM for mice irradiated with either a mixed field or gamma rays increased resistance to Klebsiella pneumoniae-induced infections.

  3. Neutron Reference Benchmark Field Specifications: ACRR Polyethylene-Lead-Graphite (PLG) Bucket Environment (ACRR-PLG-CC-32-CL).

    SciTech Connect

    Vega, Richard Manuel; Parm, Edward J.; Griffin, Patrick J.; Vehar, David W.

    2015-07-01

    This report was put together to support the International Atomic Energy Agency (IAEA) REAL- 2016 activity to validate the dosimetry community’s ability to use a consistent set of activation data and to derive consistent spectral characterizations. The report captures details of integral measurements taken in the Annular Core Research Reactor (ACRR) central cavity with the Polyethylene-Lead-Graphite (PLG) bucket, reference neutron benchmark field. The field is described and an “a priori” calculated neutron spectrum is reported, based on MCNP6 calculations, and a subject matter expert (SME) based covariance matrix is given for this “a priori” spectrum. The results of 37 integral dosimetry measurements in the neutron field are reported.

  4. Ultra-high field NMR studies of antibody binding and site-specific phosphorylation of alpha-synuclein.

    PubMed

    Sasakawa, Hiroaki; Sakata, Eri; Yamaguchi, Yoshiki; Masuda, Masami; Mori, Tetsuya; Kurimoto, Eiji; Iguchi, Takeshi; Hisanaga, Shin-ichi; Iwatsubo, Takeshi; Hasegawa, Masato; Kato, Koichi

    2007-11-23

    Although biological importance of intrinsically disordered proteins is becoming recognized, NMR analyses of this class of proteins remain as tasks with more challenge because of poor chemical shift dispersion. It is expected that ultra-high field NMR spectroscopy offers improved resolution to cope with this difficulty. Here, we report an ultra-high field NMR study of alpha-synuclein, an intrinsically disordered protein identified as the major component of the Lewy bodies. Based on NMR spectral data collected at a 920 MHz proton frequency, we performed epitope mapping of an anti-alpha-synuclein monoclonal antibody, and furthermore, characterized conformational effects of phosphorylation at Ser129 of alpha-synuclein.

  5. Ultra-high field NMR studies of antibody binding and site-specific phosphorylation of {alpha}-synuclein

    SciTech Connect

    Sasakawa, Hiroaki |; Sakata, Eri; Yamaguchi, Yoshiki; Masuda, Masami |; Mori, Tetsuya; Kurimoto, Eiji; Iguchi, Takeshi; Hisanaga, Shin-ichi; Iwatsubo, Takeshi; Hasegawa, Masato; Kato, Koichi |

    2007-11-23

    Although biological importance of intrinsically disordered proteins is becoming recognized, NMR analyses of this class of proteins remain as tasks with more challenge because of poor chemical shift dispersion. It is expected that ultra-high field NMR spectroscopy offers improved resolution to cope with this difficulty. Here, we report an ultra-high field NMR study of {alpha}-synuclein, an intrinsically disordered protein identified as the major component of the Lewy bodies. Based on NMR spectral data collected at a 920 MHz proton frequency, we performed epitope mapping of an anti-{alpha}-synuclein monoclonal antibody, and furthermore, characterized conformational effects of phosphorylation at Ser129 of {alpha}-synuclein.

  6. A field-based method to derive macroinvertebrate benchmark for specific conductivity adapted for small data sets and demonstrated in the Hun-Tai River Basin, Northeast China.

    PubMed

    Zhao, Qian; Jia, Xiaobo; Xia, Rui; Lin, Jianing; Zhang, Yuan

    2016-09-01

    Ionic mixtures, measured as specific conductivity, have been increasingly concerned because of their toxicities to aquatic organisms. However, identifying protective values of specific conductivity for aquatic organisms is challenging given that laboratory test systems cannot examine more salt-intolerant species nor effects occurring in streams. Large data sets used for deriving field-based benchmarks are rarely available. In this study, a field-based method for small data sets was used to derive specific conductivity benchmark, which is expected to prevent the extirpation of 95% of local taxa from circum-neutral to alkaline waters dominated by a mixture of SO4(2-) and HCO3(-) anions and other dissolved ions. To compensate for the smaller sample size, species level analyses were combined with genus level analyses. The benchmark is based on extirpation concentration (XC95) values of specific conductivity for 60 macroinvertebrate genera estimated from 296 sampling sites in the Hun-Tai River Basin. We derived the specific conductivity benchmark by using a 2-point interpolation method, which yielded the benchmark of 249 μS/cm. Our study tailored the method that was developed by USEPA to derive aquatic life benchmark for specific conductivity for basin scale application, and may provide useful information for water pollution control and management. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Up-regulation of expression of selected genes in human bone cells with specific capacitively coupled electric fields.

    PubMed

    Clark, Charles C; Wang, Wei; Brighton, Carl T

    2014-07-01

    The objective of the described experiments was to determine the electrical parameters that lead to optimal expression of a number of bone-related genes in cultured human bone cells exposed to a capacitively coupled electric field. Human calvarial osteoblasts were grown in modified plastic Cooper dishes in which the cells could be exposed to various capacitively coupled electric fields. The optimal duration of stimulation and optimal duration of response to the electrical field, and the optimal amplitude, frequency and duty cycle were all determined for each of the genes analyzed. Results indicated that a capacitively coupled electric field of 60 kHz, 20 mV/cm, 50% duty cycle for 2 h duration per day significantly up-regulated mRNA expression of a number of transforming growth factor (TGF)-β family genes (bone morphogenetic proteins (BMP)-2 and -4, TGF-β1, - β2 and -β3) as well as fibroblast growth factor (FGF)-2, osteocalcin (BGP) and alkaline phosphatase (ALP). Protein levels of BMP-2 and -4, and TGF-β1 and - β2 were also elevated. The clinical relevance of these findings in the context of a noninvasive treatment modality for delayed union and nonunion fracture healing is discussed.

  8. Specific features of electric field in the atmosphere and Radon emanations in Tunkin Basin of Baikal rift zone

    NASA Astrophysics Data System (ADS)

    Soloviev, S.; Loktev, D.

    2013-05-01

    Development of methods for diagnosing local crust encourages finding new ways for preventing hazardous geologic phenomena. Using measurements of several geophysical fields in addition to seismic methods enables to improve the existing methods and increase their reliability. In summer of 2009 and 2010, complex geophysical acquisition company was organized in the Tunkin Basin of the Baikal rift zone in South-Eastern Siberia, that runs 200 km to East-West from the southern tip of Baikal. Stationary observations were carried out in the central part of the Tunkin Basin, at the Geophysical observatory "I" of Institute of Solar-Terrestrial Physics of Siberian Branch of RAS and "II" near the Arshan settlement. Along with observations of microseismic noise and electric field variations in soil, there were performed measurements of electric field strength (Ez) in lowest atmosphere and volumetric activity of natural Radon in subsoil. Meteorological parameters were monitored with the use of DavisVantagePro meteorological stations. The analysis of observations showed that characteristic features of electric field in near-surface atmosphere are majorly defined by complex orography of the place and, consequently, by quickly changing meteorological conditions: thunderstorm activity and other mesometeorological events (with characteristic scale of tens of km and few hours long) in nearby rocks. The results of Ez(t) measurements performed under "good" weather conditions showed that the character of field variations depended on the local time with their maximum in daylight hours and minimum in the night. The analysis of Radon volumetric activity evidenced that its variations are influenced by atmospheric pressure and tides, and such influence is different at points "I" and "II". In particular, the tidal and atmospheric influence on Radon variations is more pronounced at "II" if compared to "I", which can be explained by locations of the registration points. Registration Point "II" is

  9. Monte Carlo study of the potential reduction in out-of-field dose using a patient-specific aperture in pencil beam scanning proton therapy.

    PubMed

    Dowdell, Stephen J; Clasie, Benjamin; Depauw, Nicolas; Metcalfe, Peter; Rosenfeld, Anatoly B; Kooy, Hanne M; Flanz, Jacob B; Paganetti, Harald

    2012-05-21

    This study is aimed at identifying the potential benefits of using a patient-specific aperture in proton beam scanning. For this purpose, an accurate Monte Carlo model of the pencil beam scanning (PBS) proton therapy (PT) treatment head at Massachusetts General Hospital (MGH) was developed based on an existing model of the passive double-scattering (DS) system. The Monte Carlo code specifies the treatment head at MGH with sub-millimeter accuracy. The code was configured based on the results of experimental measurements performed at MGH. This model was then used to compare out-of-field doses in simulated DS treatments and PBS treatments. For the conditions explored, the penumbra in PBS is wider than in DS, leading to higher absorbed doses and equivalent doses adjacent to the primary field edge. For lateral distances greater than 10 cm from the field edge, the doses in PBS appear to be lower than those observed for DS. We found that placing a patient-specific aperture at nozzle exit during PBS treatments can potentially reduce doses lateral to the primary radiation field by over an order of magnitude. In conclusion, using a patient-specific aperture has the potential to further improve the normal tissue sparing capabilities of PBS.

  10. Monoclonal antibodies specific to sailfish serum albumin: development of an assay for the identification of fish species in the field.

    PubMed

    Rossi, E A; Shepard, S R; Poyer, J C; Hartmann, J X

    1992-06-01

    Balb/c mice were immunized with albumin purified from sailfish (Istiophorus albicans) serum. Hybridomas were produced and screened by ELISA for reactivity with the purified albumins of sailfish, blue marlin (Makaira nigricans) and white marlin (Tetrapturus albidus). Monoclonal antibodies (MAbs) from 16 different clones exhibited activity against sailfish albumin. Thirteen of the MAbs showed cross-reactivity with the marlin species. Three MAbs exhibited distinct specificity for sailfish albumin. One of these species specific MAbs (M2D1) was conjugated to horseradish peroxidase (HRP) in order to construct an ELISA for identification of sailfish from serum. The ELISA for sailfish correctly identified eight sailfish from 26 billfish serum samples. The MAb-peroxidase conjugate was highly specific toward sailfish in that no reaction against heterologous species was detected.

  11. Physiological observations validate finite element models for estimating subject-specific electric field distributions induced by transcranial magnetic stimulation of the human motor cortex.

    PubMed

    Opitz, Alexander; Legon, Wynn; Rowlands, Abby; Bickel, Warren K; Paulus, Walter; Tyler, William J

    2013-11-01

    Recent evidence indicates subject-specific gyral folding patterns and white matter anisotropy uniquely shape electric fields generated by TMS. Current methods for predicting the brain regions influenced by TMS involve projecting the TMS coil position or center of gravity onto realistic head models derived from structural and functional imaging data. Similarly, spherical models have been used to estimate electric field distributions generated by TMS pulses delivered from a particular coil location and position. In the present paper we inspect differences between electric field computations estimated using the finite element method (FEM) and projection-based approaches described above. We then more specifically examined an approach for estimating cortical excitation volumes based on individualistic FEM simulations of electric fields. We evaluated this approach by performing neurophysiological recordings during MR-navigated motormapping experiments. We recorded motor evoked potentials (MEPs) in response to single pulse TMS using two different coil orientations (45° and 90° to midline) at 25 different locations (5×5 grid, 1cm spacing) centered on the hotspot of the right first dorsal interosseous (FDI) muscle in left motor cortex. We observed that motor excitability maps varied within and between subjects as a function of TMS coil position and orientation. For each coil position and orientation tested, simulations of the TMS-induced electric field were computed using individualistic FEM models and compared to MEP amplitudes obtained during our motormapping experiments. We found FEM simulations of electric field strength, which take into account subject-specific gyral geometry and tissue conductivity anisotropy, significantly correlated with physiologically observed MEP amplitudes (rmax=0.91, p=1.8×10(-5) rmean=0.81, p=0.01). These observations validate the implementation of individualistic FEM models to account for variations in gyral folding patterns and tissue

  12. Conversion of upland to paddy field specifically alters the community structure of archaeal ammonia oxidizers in an acid soil

    NASA Astrophysics Data System (ADS)

    Alam, M. S.; Ren, G. D.; Lu, L.; Zheng, Y.; Peng, X. H.; Jia, Z. J.

    2013-08-01

    The function of ammonia-oxidizing archaea (AOA) and bacteria (AOB) depends on the major energy-generating compounds (i.e., ammonia and oxygen). The diversification of AOA and AOB communities along ecological gradients of substrate availability in a complex environment have been much debated but rarely tested. In this study, two ecosystems of maize and rice crops under different fertilization regimes were selected to investigate the community diversification of soil AOA and AOB upon conversion of an upland field to a paddy field and long-term field fertilization in an acid soil. Real-time quantitative polymerase chain reaction of ammonia monooxygenase (amoA) genes demonstrated that the abundance of AOA was significantly stimulated after conversion of upland to paddy soils for more than 100 yr, whereas a slight decline in AOB numbers was observed. Denaturing gradient gel electrophoresis fingerprints of amoA genes further revealed remarkable changes in the community compositions of AOA after conversion of aerobic upland to flooded paddy field. Sequencing analysis revealed that upland soil was dominated by AOA within the soil group 1.1b lineage, whereas the marine group 1.1a-associated lineage predominated in AOA communities in paddy soils. Irrespective of whether the soil was upland or paddy soil, long-term field fertilization led to increased abundance of amoA genes in AOA and AOB compared with control treatments (no fertilization), whereas archaeal amoA gene abundances outnumbered their bacterial counterparts in all samples. Phylogenetic analyses of amoA genes showed that Nitrosospira cluster-3-like AOB dominated bacterial ammonia oxidizers in both paddy and upland soils, regardless of fertilization treatment. The results of this study suggest that the marine group 1.1a-associated AOA will be better adapted to the flooded paddy field than AOA ecotypes of the soil group 1.1b lineage, and indicate that long-term flooding is the dominant selective force driving the

  13. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Effects of Transverse Field on Internal Energy and Specific Heat of a Molecular-Based Materials

    NASA Astrophysics Data System (ADS)

    Jiang, Wei; Yu, Gui-Hong; Zhang, Fan; Wang, Wei; Jiang, Yuan

    2009-11-01

    The molecular-based magnetic materials AFeIIFeIII (C2O4)3 have a honeycomb structure in which FeII (S = 2) and FeIII (S = 5/2) occupy sites alternately. They can be described as mixed spin-2 and spin-5/2 Ising model with ferrimagnetic interlayer coupling. The influences of the transverse field on the internal energy and the specific heat of the molecular-based magnetic system have been studied numerically by using the effective-field theory with self-spin correlations and the differential operator technique.

  14. Analysis of in situ electric field and specific absorption rate in human models for wireless power transfer system with induction coupling.

    PubMed

    Sunohara, Tetsu; Hirata, Akimasa; Laakso, Ilkka; Onishi, Teruo

    2014-07-21

    This study investigates the specific absorption rate (SAR) and the in situ electric field in anatomically based human models for the magnetic field from an inductive wireless power transfer system developed on the basis of the specifications of the wireless power consortium. The transfer system consists of two induction coils covered by magnetic sheets. Both the waiting and charging conditions are considered. The transfer frequency considered in this study is 140 kHz, which is within the range where the magneto-quasi-static approximation is valid. The SAR and in situ electric field in the chest and arm of the models are calculated by numerically solving the scalar potential finite difference equation. The electromagnetic modelling of the coils in the wireless power transfer system is verified by comparing the computed and measured magnetic field distributions. The results indicate that the peak value of the SAR averaged over a 10 g of tissue and that of the in situ electric field are 72 nW kg(-1) and 91 mV m(-1) for a transmitted power of 1 W, Consequently, the maximum allowable transmitted powers satisfying the exposure limits of the SAR (2 W kg(-1)) and the in situ electric field (18.9 V m(-1)) are found to be 28 MW and 43 kW. The computational results show that the in situ electric field in the chest is the most restrictive factor when compliance with the wireless power transfer system is evaluated according to international guidelines.

  15. Crystal symmetry and high-magnetic-field specific heat of SrCu{sub 2}(BO{sub 3}){sub 2}

    SciTech Connect

    Jorge, G.A.; Jaime, M.; Harrison, N.; Stern, R.; Bonca, J.; El Shawish, S.; Batista, C.D.; Dabkowska, H.A.; Gaulin, B.D.

    2005-03-01

    We report measurements of the specific heat of the quantum spin liquid system SrCu{sub 2}(BO{sub 3}){sub 2} in continuous magnetic fields H of up to 33 T. The specific heat data, when combined with a finite temperature Lanczos diagonalization of the Shastry-Sutherland Hamiltonian, indicate the presence of a nearest neighbor Dzyaloshinsky-Moriya (DM) interaction that violates the crystal symmetry. Moreover, the same DM interaction is required to explain the observed electron spin resonance lines for H parallel c.

  16. Preliminary Observations on Sensitivity and Specificity of Magnetization Transfer Asymmetry for Imaging Myelin of Rat Brain at High Field

    PubMed Central

    Kim, Jae-Woong; Choi, Jiye; Cho, Janggeun; Lee, Chulhyun; Jeon, Daejong; Park, Sung-Hong

    2015-01-01

    Magnetization transfer ratio (MTR) has been often used for imaging myelination. Despite its high sensitivity, the specificity of MTR to myelination is not high because tissues with no myelin such as muscle can also show high MTR. In this study, we propose a new magnetization transfer (MT) indicator, MT asymmetry (MTA), as a new method of myelin imaging. The experiments were performed on rat brain at 9.4 T. MTA revealed high signals in white matter and significantly low signals in gray matter and muscle, indicating that MTA has higher specificity than MTR. Demyelination and remyelination studies demonstrated that the sensitivity of MTA to myelination was as high as that of MTR. These experimental results indicate that MTA can be a good biomarker for imaging myelination. In addition, MTA images can be efficiently acquired with an interslice MTA method, which may accelerate clinical application of myelin imaging. PMID:26413534

  17. Preliminary Observations on Sensitivity and Specificity of Magnetization Transfer Asymmetry for Imaging Myelin of Rat Brain at High Field.

    PubMed

    Kim, Jae-Woong; Choi, Jiye; Cho, Janggeun; Lee, Chulhyun; Jeon, Daejong; Park, Sung-Hong

    2015-01-01

    Magnetization transfer ratio (MTR) has been often used for imaging myelination. Despite its high sensitivity, the specificity of MTR to myelination is not high because tissues with no myelin such as muscle can also show high MTR. In this study, we propose a new magnetization transfer (MT) indicator, MT asymmetry (MTA), as a new method of myelin imaging. The experiments were performed on rat brain at 9.4 T. MTA revealed high signals in white matter and significantly low signals in gray matter and muscle, indicating that MTA has higher specificity than MTR. Demyelination and remyelination studies demonstrated that the sensitivity of MTA to myelination was as high as that of MTR. These experimental results indicate that MTA can be a good biomarker for imaging myelination. In addition, MTA images can be efficiently acquired with an interslice MTA method, which may accelerate clinical application of myelin imaging.

  18. Crystalline electric field and lattice contributions to thermodynamic properties of PrGaO3: specific heat and thermal expansion

    NASA Astrophysics Data System (ADS)

    Senyshyn, A.; Schnelle, W.; Vasylechko, L.; Ehrenberg, H.; Berkowski, M.

    2007-04-01

    The low-temperature heat capacity of perovskite-type PrGaO3 has been measured in the temperature range from 2 to 320 K. Thermodynamic standard values at 298.15 K are reported. An initial Debye temperature θD(0) = (480 ± 10) K was determined by fitting the calculated lattice heat capacity. The entropy of the derived Debye temperature functions agrees well with values calculated from thermal displacement parameters and from atomistic simulations. The thermal expansion and the Grüneisen parameter, arising from a coupling of crystal field states of Pr3+ ion and phonon modes at low temperature, were analysed.

  19. Calculation of the paramagnetic susceptibility and specific heat in UGa 2 and UPd 2Al 3 from ab initio crystal field theory

    NASA Astrophysics Data System (ADS)

    Richter, Manuel; Diviš, Martin; Forstreuter, Jörg; Koepernik, Klaus; Steinbeck, Lutz; Eschrig, Helmut

    1997-02-01

    In the framework of the self-interaction corrected local density approximation, ab initio calculations have been carried out to obtain crystal field parameters for the paramagnetic state of UGa 2 and UPd 2Al 3. In two sets of calculations localized 5f states with occupation two and three, respectively, have been assumed. Using these parameters and adjusted anisotropic molecular field constants, the paramagnetic susceptibility for both compounds and the Schottky contribution to the specific heat in UPd 2Al 3 have been obtained by crystal field model calculations. Very good agreement between theoretical and experimental data is found for 5f 2 occupation in UGa 2. For UPd 2Al 3, the 5f 2 assumption yields qualitatively reasonable results as well, but it does not explain the T = 50 K maximum in the experimental data.

  20. Rapid, specific, simple, in-field detection of Xanthomonas campestris pathovar musacearum by loop-mediated isothermal amplification.

    PubMed

    Hodgetts, J; Hall, J; Karamura, G; Grant, M; Studholme, D J; Boonham, N; Karamura, E; Smith, J J

    2015-12-01

    To develop and evaluate a loop-mediated isothermal amplification (LAMP) assay for Xanthomonas campestris pathovar musacearum (Xcm), the causal agent of banana Xanthomonas wilt, a major disease of banana in Africa. LAMP primers were designed to the general secretion pathway protein D gene and tested against 17 isolates of Xcm encompassing the known genetic and geographic diversity of the bacterium and all isolates were detected. Seventeen other Xanthomonas isolates, including closely related Xanthomonas vasicola, other bacterial pathogens/endophytes of Musa and two healthy Musa varieties gave negative results with the LAMP assay. The assay showed good sensitivity, detecting as little as 51 fg of Xcm DNA, a greater level of sensitivity than that of an Xcm PCR assay. Amplification with the LAMP assay was very rapid, typically within 9 min from bacterial cultures. Symptomatic field samples of Musa from Uganda were tested and all produced amplification in less than 13 min. The LAMP assay provides rapid, sensitive detection of the pathogen that is ideally suited for deployment in laboratories with basic facilities and in-field situations. This is the first LAMP assay for Xcm which provides a significant improvement compared to existing diagnostics. © 2015 Crown copyright. © 2015 The Society for Applied Microbiology.

  1. Patient-specific models of deep brain stimulation: Influence of field model complexity on neural activation predictions

    PubMed Central

    Chaturvedi, Ashutosh; Butson, Christopher R.; Lempka, Scott F.; Cooper, Scott E.; McIntyre, Cameron C.

    2010-01-01

    Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become the surgical therapy of choice for medically intractable Parkinson’s disease. However, quantitative understanding of the interaction between the electric field generated by DBS and the underlying neural tissue is limited. Recently, computational models of varying levels of complexity have been used to study the neural response to DBS. The goal of this study was to evaluate the quantitative impact of incrementally incorporating increasing levels of complexity into computer models of STN DBS. Our analysis focused on the direct activation of experimentally measureable fiber pathways within the internal capsule (IC). Our model system was customized to an STN DBS patient and stimulation thresholds for activation of IC axons were calculated with electric field models that ranged from an electrostatic, homogenous, isotropic model to one that explicitly incorporated the voltage-drop and capacitance of the electrode-electrolyte interface, tissue encapsulation of the electrode, and diffusion-tensor based 3D tissue anisotropy and inhomogeneity. The model predictions were compared to experimental IC activation defined from electromyographic (EMG) recordings from eight different muscle groups in the contralateral arm and leg of the STN DBS patient. Coupled evaluation of the model and experimental data showed that the most realistic predictions of axonal thresholds were achieved with the most detailed model. Furthermore, the more simplistic neurostimulation models substantially overestimated the spatial extent of neural activation. PMID:20607090

  2. Low-temperature specific heat of polycrystalline YBa sub 2 Cu sub 3 O sub 6. 70 in applied magnetic fields of 0, 1, 2, and 3 T

    SciTech Connect

    Stupp, S.E.; Friedmann, T.A.; Rice, J.P.; Schweinfurth, R.A.; Van Harlingen, D.J.; Ginsberg, D.M. )

    1991-06-01

    We have measured the specific heat of sintered YBa{sub 2}Cu{sub 3}O{sub 6.70} powder between 1.85 and 77 K in zero magnetic field, and between 1.75 and 9.5 K in applied fields up to 3 T. The sample was characterized by x-ray diffraction, scanning electron microscopy, iodometric titration, and magnetic susceptibility. The onset of the diamagnetic transition to the superconducting state occurred at {ital T}{sub {ital c}}=67 K. For the specific heat in nonzero applied magnetic field, there is an increase in the magnitude of the term that is linear in temperature, and a decrease in the term that is cubic in temperature. These results agree with earlier results on the {ital T}{sub {ital c}}=90 K phase of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. The data for nonzero applied fields were analyzed by using Ginzburg-Landau theory in the London limit for a uniaxially symmetric superconductor.

  3. Ion Species Fractions in the Far-Field Plume of a High-Specific Impulse Hall Thruster

    NASA Technical Reports Server (NTRS)

    Hofer, Richard R.; Gallimore, Alec D.

    2003-01-01

    An ExB probe was used to measure the ion species fractions of Xe(+), Xe(2+), and Xe(3+) in the far-field plume of the NASA-173Mv2 laboratory-model Hall thruster. The thruster was operated at a constant xenon flow rate of 10 milligrams per second and discharge voltages of 300 to 900 V. The ExB probe was placed two meters downstream of the thruster exit plane on the thruster centerline. At a discharge voltage of 300 V, the species fractions of Xe(2+) and Xe(3+) were lower, but still consistent with, previous Hall thruster studies using other mass analyzers. Over discharge voltages of 300 to 900 V, the Xe(2+) species fractions increased from 0.04 to 0.12 and the Xe(3+) species fraction increased from 0.01 to 0.02.

  4. Response of ground beetle (Coleoptera: Carabidae) field populations to four years of Lepidoptera-specific Bt corn production.

    PubMed

    Floate, K D; Cárcamo, H A; Blackshaw, R E; Postman, B; Bourassa, S

    2007-10-01

    Pitfall traps were used to monitor populations of ground beetles (Coleoptera: Carabidae) in plots of corn grown in continuous cultivation during a 4-yr period (2000-2003). Treatments included transgenic corn expressing a Bt Cry protein with efficacy specific against Lepidoptera (Bt), conventional corn grown with insecticide application (I), and the same conventional cultivar grown without insecticide application (NI). Mixed-model analyses of variance were performed on pitfall captures of beetles combined across weeks to give seasonal sums. Effects of corn treatment were not detected (P > 0.05) on total beetle abundance or species richness in any year. Effects of corn treatment on individual taxa were detected (P < 0.05) for 3 of the 39 species-by-year combinations examined. Effects of near significance (P < 0.08) were detected for an additional two species. In 2001, captures of Amara farcta Leconte and Harpalus amputatus Say were lower in Bt plots than in I or NI plots. In 2003, captures of Amara apricaria (Paykull) and Amara carinata (Leconte) were higher in Bt plots than in I or NI plots. Also in 2003, captures of Poecilus scitulus Leconte were higher in I plots than in Bt or NI plots. These patterns were not repeated among years. Results of this study indicate that cultivation of Lepidoptera-specific Bt corn in southern Alberta does not appreciably affect ground beetle populations.

  5. SU-D-304-06: Measurement of LET in Patient-Specific Proton Therapy Treatment Fields Using Optically Stimulated Luminescence Detectors

    SciTech Connect

    Granville, DA; Sahoo, N; Sawakuchi, GO

    2015-06-15

    Purpose: To investigate the use of optically stimulated luminescence (OSL) detectors (OSLDs) for measurements of dose-averaged linear energy transfer (LET) in patient-specific proton therapy treatment fields. Methods: We used Al{sub 2}O{sub 3}:C OSLDs made from the same material as commercially available nanoDot OSLDs from Landauer, Inc. We calibrated two parameters of the OSL signal as functions of LET in therapeutic proton beams: the ratio of the ultraviolet and blue emission intensities (UV/blue ratio) and the OSL curve shape. These calibration curves were created by irradiating OSLDs in passively scattered beams of known LET (0.96 to 3.91 keV/µm). The LET values were determined using a validated Monte Carlo model of the beamline. We then irradiated new OSLDs with the prescription dose (16 to 74 cGy absorbed dose to water) at the center of the spread-out Bragg peak (SOBP) of four patient-specific treatment fields. From readouts of these OSLDs, we determined both the UV/blue ratio and OSL curve shape parameters. Combining these parameters with the calibration curves, we were able to measure LET using the OSLDs. The measurements were compared to the theoretical LET values obtained from Monte Carlo simulations of the patient-specific treatments fields. Results: Using the UV/blue ratio parameter, we were able to measure LET within 3.8%, 6.2%, 5.6% and 8.6% of the Monte Carlo value for each of the patient fields. Similarly, using the OSL curve shape parameter, LET measurements agreed within 0.5%, 11.0%, 2.5% and 7.6% for each of the four fields. Conclusion: We have demonstrated a method to verify LET in patient-specific proton therapy treatment fields using OSLDs. The possibility of enhancing biological effectiveness of proton therapy treatment plans by including LET in the optimization has been previously shown. The LET verification method we have demonstrated will be useful in the quality assurance of such LET optimized treatment plans. DA Granville received

  6. An analysis of specific lower extremity injury rates on grass and FieldTurf playing surfaces in National Football League Games: 2000-2009 seasons.

    PubMed

    Hershman, Elliott B; Anderson, Robert; Bergfeld, John A; Bradley, James P; Coughlin, Michael J; Johnson, Robert J; Spindler, Kurt P; Wojtys, Edward; Powell, John W

    2012-10-01

    Players in the National Football League (NFL) sustain injuries every season as the result of their participation. One factor associated with the rate of injury is the type of playing surface on which the players participate. There is no difference in the rate of knee sprains and ankle sprains during NFL games when comparing rates of those injuries during games played on natural grass surfaces with rates of those injuries during games played on the artificial surface FieldTurf. Descriptive epidemiology study. The NFL records injury and exposure (ie, game) data as part of its injury surveillance system. During the 2000-2009 NFL seasons, there were 2680 games (5360 team games) played on grass or artificial surfaces. Specifically, 1356 team games were played on FieldTurf and 4004 team games were played on grass. We examined the 2000-2009 game-related injury data from those games as recorded by the injury surveillance system. The data included the injury diagnosis, the date of injury, and the surface at the time of injury. The injury data showed that 1528 knee sprains and 1503 ankle sprains occurred during those games. We calculated injury rates for knee sprains and ankle sprains-specifically, medial collateral ligament (MCL) sprains, anterior cruciate ligament (ACL) sprains, eversion ankle sprains, and inversion ankle sprains-using incidence density ratios (IDRs). We used a Poisson model and logistic regression odds ratios to validate the IDR analysis. A multivariate logistic regression model was used to adjust the odds ratio for weather conditions. The observed injury rate of knee sprains on FieldTurf was 22% (IDR = 1.22, 95% confidence interval [CI], 1.09-1.36) higher than on grass, and the injury rate of ankle sprains on FieldTurf was 22% (IDR = 1.22, 95% CI, 1.09-1.36) higher than on grass. These differences are statistically significant. Specifically, the observed injury rates of ACL sprains and eversion ankle sprains on FieldTurf surfaces were 67% (P < .001) and

  7. Importance of Diffusion and Compound-Specific Mixing for Conservative and Reactive Transport in Groundwater: An Investigation from Pore to Field Scale

    NASA Astrophysics Data System (ADS)

    Rolle, M.; Chiogna, G.; Hochstetler, D. L.; Kitanidis, P. K.

    2013-12-01

    Mixing processes significantly affect and limit contaminant transport and transformation rates in the subsurface. The correct quantification of mixing in groundwater systems must account for diffusion, local-scale dispersion and the flow variability in heterogeneous flow fields. Recent results of multi-tracer laboratory experiments revealed the significant effect of compound-specific diffusive properties on the physical displacement of dissolved species across a representative range of groundwater flow velocities. The goal of this study is to investigate the role of diffusion and compound-specific mixing for solute transport across a range of scales including: (i) pore-scale (~10^-2 m), (ii) laboratory bench-scale (~10^0 m) and (iii) field-scale (~10^2 m). We investigate both conservative and mixing-controlled reactive transport using pore-scale modeling, flow-through laboratory experiments and simulations, and field-scale numerical modeling of complex heterogeneous hydraulic conductivity fields with statistical properties similar to the ones reported for the extensively investigated Borden aquifer (Ontario, Canada) and Columbus aquifer (Mississippi, USA). We consider different steady-state and transient transport scenarios. For the conservative cases we use as a metric of mixing the exponential of the Shannon entropy to quantify solute dilution either in a given volume (dilution index) or in a given solute flux (flux-related dilution index). The decrease in the mass and the mass-flux of the contaminant plumes is evaluated to quantify reactive mixing. The results show that diffusive processes, occurring at the small-scale of a pore channel, strongly affect conservative and reactive solute transport at larger macroscopic scales. The outcomes of our study illustrate the need to consider and properly account for compound-specific diffusion and mixing limitations in order to accurately describe and predict conservative and reactive transport in porous media.

  8. Retinoic acid is required for specification of the ventral eye field and for Rathke's pouch in the avian embryo.

    PubMed

    Maden, Malcolm; Blentic, Aida; Reijntjes, Susan; Seguin, Sophie; Gale, Emily; Graham, Anthony

    2007-01-01

    We have investigated the role of retinoic acid (RA) in eye development using the vitamin A deficient quail model system, which overcomes problems of retinoic acid synthesising enzyme redundancy in the embryo. In the absence of retinoic acid, the ventral optic stalk and ventral retina are missing, whereas the dorsal optic stalk and dorsal retina develop appropriately. Other ocular abnormalities observed were a thinner retina and the lack of differentiation of the lens. In an attempt to explain this, we studied the expression of various dorsally and ventrally expressed genes such as Pax2, Pax6, Tbx6, Vax2, Raldh1 and Raldh3 and noted that they were unchanged in their expression patterns. In contrast, the RA catabolising enzymes Cyp26A1 and Cyp26B1 which are known to be RA-responsive were not expressed at all in the developing eye. At much earlier stages, the expression domain of Shh in the prechordal plate was reduced, as was Nkx2.1 and we suggest a model whereby the eye field is specified according to the concentration of SHH protein that is present. We also describe another organ, Rathke's pouch which fails to develop in the absence of retinoic acid. We attribute this to the down-regulation of Bmp2, Shh and Fgf8 which are known to be involved in the induction of this structure.

  9. Changes in NGF/c-Fos colocalization in specific limbic structures of juvenile and aged rats after open field stimulation.

    PubMed

    Badowska-Szalewska, E; Klejbor, I; Cecot, T; Domaradzka-Pytel, B; Ludkiewicz, B; Moryś, J

    2009-08-01

    Changes in NGF release during stressful events have been associated with the activation of neurons expressing NGF receptors. This study examined the influence of acute stress-induced stimulation on NGF/c-Fos colocalization in the following limbic regions: the paraventricular (PV) nucleus of the hypothalamus, medial (MeA) nucleus of the amygdala, and CA3 hippocampus. Juvenile (P21) and aged rats (P360) were exposed to a 15-minute acute open field (OF) test. Double immunofluorescence staining, used to detect NGF-ir and c-Fos-ir cells, revealed a higher percentage of NGF/c-Fos-ir neurons in the P21 control group than in the P360 control group. Under OF acute stimulation, a statistically significant (p < 0.05) increase of NGF/c-Fos level in CA3 of juvenile animals and in PV and CA3 of the aged rats was observed. These observations indicate that the investigated structures in both age groups show a different response to acute OF stimulation. Acute OF affects the levels of NGF/c-Fos more significantly in aged rats.

  10. Task specific evaluation of clinical full field digital mammography systems using the Fourier definition of the Hotelling observer SNR

    NASA Astrophysics Data System (ADS)

    Liu, Haimo; Badano, Aldo; Benevides, Luis; Chakrabarti, Kish; Kaczmarek, Richard V.; Kyprianou, Iacovos S.

    2010-04-01

    Pixel Signal to Noise Ratio (SNR) is a commonly used clinical metric for evaluating mammography. However, we showed in this paper, the pixel SNR can produce misleading system detectability when image processing is utilized. We developed a simple, reliable and clinically applicable methodology to evaluate mammographic imaging systems using a task SNR that accounts for the imaging system performance in the presence of the patient. We used the Hotelling observer method in spatial frequency domain to calculate the task SNR of small disk test objects embedded in the breast tissue-equivalent series (BRTES) phantom for GE Senographe DS Full Field Digital Mammography (FFDM) system. The results were compared to the calculation of pixel SNR. We calculated the Hotelling observer SNR by estimating the generalized modulation transfer function (GMTF), generalized normalized noise power spectrum (GNNPS) and generalized noise equivalent quanta (GNEQ) in the presence of the breast phantom. The task SNR we calculated increased with the square root of the exposure as expected. Furthermore, we showed that the method is stable under image processing. The task SNR is a more reliable method for evaluating the performance of imaging systems especially under realistic clinical conditions where patient equivalent phantoms or image processing is used.

  11. Rock specific hydraulic fracturing and matrix acidizing to enhance a geothermal system — Concepts and field results

    NASA Astrophysics Data System (ADS)

    Zimmermann, Günter; Blöcher, Guido; Reinicke, Andreas; Brandt, Wulf

    2011-04-01

    Enhanced geothermal systems (EGS) are engineered reservoirs developed to extract economic amounts of heat from low permeability and/or porosity geothermal resources. To enhance the productivity of reservoirs, a site specific concept is necessary to actively make reservoir conditions profitable using specially adjusted stimulation treatments, such as multi fracture concepts and site specific well path design. The results of previously performed stimulation treatments in the geothermal research well GtGrSk4/05 at Groß Schönebeck, Germany are presented. The reservoir is located at a 4100-4300 m depth within the Lower Permian of the NE German Basin with a bottom-hole temperature of 150 °C. The reservoir rock is classified by two lithological units from bottom to top: volcanic rocks (andesitic rocks) and siliciclastics ranging from conglomerates to fine-grained sandstones (fluvial sediments). The stimulation treatments included multiple hydraulic stimulations and an acid treatment. In order to initiate a cross-flow from the sandstone layer, the hydraulic stimulations were performed in different depth sections (two in the sandstone section and one in the underlying volcanic section). In low permeability volcanic rocks, a cyclic hydraulic fracturing treatment was performed over 6 days in conjunction with adding quartz in low concentrations to maintain a sustainable fracture performance. Flow rates of up to 150 l/s were realized, and a total of 13,170 m 3 of water was injected. A hydraulic connection to the sandstone layer was successfully achieved in this way. However, monitoring of the water level in the offsetting well EGrSk3/90, which is 475 m apart at the final depth, showed a very rapid water level increase due to the stimulation treatment. This can be explained by a connected fault zone within the volcanic rocks. Two gel-proppant treatments were performed in the slightly higher permeability sandstones to obtain long-term access to the reservoir rocks. During each

  12. Large field-of-view and depth-specific cortical microvascular imaging underlies regional differences in ischemic brain

    NASA Astrophysics Data System (ADS)

    Qin, Jia; Shi, Lei; Dziennis, Suzan; Wang, Ruikang K.

    2014-02-01

    Ability to non-invasively monitor and quantify of blood flow, blood vessel morphology, oxygenation and tissue morphology is important for improved diagnosis, treatment and management of various neurovascular disorders, e.g., stroke. Currently, no imaging technique is available that can satisfactorily extract these parameters from in vivo microcirculatory tissue beds, with large field of view and sufficient resolution at defined depth without any harm to the tissue. In order for more effective therapeutics, we need to determine the area of brain that is damaged but not yet dead after focal ischemia. Here we develop an integrated multi-functional imaging system, in which SDW-LSCI (synchronized dual wavelength laser speckle imaging) is used as a guiding tool for OMAG (optical microangiography) to investigate the fine detail of tissue hemodynamics, such as vessel flow, profile, and flow direction. We determine the utility of the integrated system for serial monitoring afore mentioned parameters in experimental stroke, middle cerebral artery occlusion (MCAO) in mice. For 90 min MCAO, onsite and 24 hours following reperfusion, we use SDW-LSCI to determine distinct flow and oxygenation variations for differentiation of the infarction, peri-infarct, reduced flow and contralateral regions. The blood volumes are quantifiable and distinct in afore mentioned regions. We also demonstrate the behaviors of flow and flow direction in the arterials connected to MCA play important role in the time course of MCAO. These achievements may improve our understanding of vascular involvement under pathologic and physiological conditions, and ultimately facilitate clinical diagnosis, monitoring and therapeutic interventions of neurovascular diseases, such as ischemic stroke.

  13. Technical specifications of low-frequency radio identification bedload tracking from field experiments: Differences in antennas, tags and operators

    NASA Astrophysics Data System (ADS)

    Arnaud, F.; Piégay, H.; Vaudor, L.; Bultingaire, L.; Fantino, G.

    2015-06-01

    Low-frequency passive integrated transponders (PIT tags) have been increasingly used for tracking bedload transport in gravel-bed rivers. Prior studies have reported high recovery rates in small streams, while recovery rates remained much lower in large systems, in large part because of the limited reading distance of the tags (< 1 m). Some laboratory tests have identified controlling factors for detection ranges (tag and antenna size, tag orientation, burial, submergence, etc.). Beyond these tests, improving our understanding of PIT tag functioning, using different equipment within different environments, is still needed in order to select the most suitable device for each geomorphic context. We address this knowledge gap with technical specifications for a low-frequency radio identification (RFID) device by working for the first time with real fluvial constraints, i.e., the gravel deposits and the aquatic channel. The three-dimensional detection envelopes of two types of tags and three types of antennas are quantified as well as the effect of practices (interoperator bias, battery power) on the detection. The interoperator variability and the intertag variability can be considered as negligible. The influence of burial in dry and water-saturated sediment and the influence of water immersion are shown to be minor. Finally, we summarize practical implications for RFID bedload tracking through these experiments.

  14. Tuber-specific silencing of asparagine synthetase-1 reduces the acrylamide-forming potential of potatoes grown in the field without affecting tuber shape and yield.

    PubMed

    Chawla, Rekha; Shakya, Roshani; Rommens, Caius M

    2012-10-01

    Simultaneous silencing of asparagine synthetase (Ast)-1 and -2 limits asparagine (ASN) formation and, consequently, reduces the acrylamide-forming potential of tubers. The phenotype of silenced lines appears normal in the greenhouse, but field-grown tubers are small and cracked. Assessing the effects of silencing StAst1 and StAst2 individually, we found that yield drag was mainly linked to down-regulation of StAst2. Interestingly, tubers from untransformed scions grafted onto intragenic StAst1/2-silenced rootstock contained almost the same low ASN levels as those in the original silenced lines, indicating that ASN is mainly formed in tubers rather than being transported from leaves. This conclusion was further supported by the finding that overexpression of StAst2 caused ASN to accumulate in leaves but not tubers. Thus, ASN does not appear to be the main form of organic nitrogen transported from leaves to tubers. Because reduced ASN levels coincided with increased levels of glutamine, it appears likely that this alternative amide amino acid is mobilized to tubers, where it is converted into ASN by StAst1. Indeed, tuber-specific silencing of StAst1, but not of StAst2, was sufficient to substantially lower ASN formation in tubers. Extensive field studies demonstrated that the reduced acrylamide-forming potential achieved by tuber-specific StAst1 silencing did not affect the yield or quality of field-harvested tubers.

  15. Experimental facilitation of the sensed presence is predicted by the specific patterns of the applied magnetic fields, not by suggestibility: re-analyses of 19 experiments.

    PubMed

    St-Pierre, L S; Persinger, M A

    2006-09-01

    If all experiences are generated by brain activity, then experiences of God and spirits should also be produced by the appropriate cerebral stimulation. During the last 15 years experiments have shown that the sensed presence of a "Sentient Being" can be reliably evoked by very specific temporal patterns of weak (<1 microT) transcerebral magnetic fields applied across the temporoparietal region of the two hemispheres. Recently Granqvist et al. (2005) attributed these effects to suggestibility and exotic beliefs. Re-analyses with additional data for 407 subjects (19 experiments) showed that the magnetic configurations, not the subjects' exotic beliefs or suggestibility, were responsible for the experimental facilitation of sensing a presence. On the other hand, the subjects' histories of sensed presences before exposure to the experimental setting were moderately correlated with exotic beliefs and temporal lobe sensitivity. Several recent experiments have shown that the side attributed to the presence at the time of the experience is sensitive to the temporal parameters of the fields, the hemisphere to which they are maximized, and the person's a priori beliefs. The importance of verifying the specific timing and temporal pattern of the software-generated fields and following an effective protocol is emphasized.

  16. Field-dependent specific heat study of the spin-Peierls transition in TTF- AuS4C4(CF3)4 a)

    NASA Astrophysics Data System (ADS)

    Northby, J. A.; Greidanus, F. J. A. M.; Huiskamp, W. J.; de Jongh, L. J.; Jacobs, I. S.; Interrante, L. V.

    1982-11-01

    The compound TTF-AuS4C4(CF3)4 is one of the very few existing examples of the spin-Peierls transition, in which a system of 1D antiferromagnetic chains dimerizes spontaneously as a consequence of magnetoelastic coupling with the surrounding lattice. We have studied the spectific heat anomaly accompanying the SP transition for this compound as a function of an applied magnetic field. Our H=0 data differ considerably from those obtained earlier by Wei et al., and in fact remove the discrepancy found by them between their results for TTF-AuS4C4(CF3)4 and the isomorphous TTF-CuS4C4(CF3)4. The differences between the two experiments are probably due to thermal relaxation effects. The combination of the specific heat data now available confirms the conclusion drawn from our previous field-dependent differential susceptibility studies on the Au compound, namely that the SP transition involves a considerable degree of short-range order, starting to develop below T=1.2 Tsp. We have been able to follow the specific heat anomaly for fields up to the multicritical point in the H-T phase diagram.

  17. Specific heats and thermodynamic critical fields in Zn-doped YBa2Cu3O(7-x) according to an induced-pairing model

    NASA Technical Reports Server (NTRS)

    Eagles, D. M.

    1993-01-01

    Electronic specific heats and thermodynamic critical fields are calculated in a mean-field version of an induced-pairing model for superconductivity, and compared with results of Loram et al. (1990) on YBa2(Cu(1-y)Zn(y))3O(7-x). This model involves induction of pairing of holes in a wideband by strongly bound electronlike pairs. It is assumed that the planar hole concentration for no Zn addition is close to, but slightly higher than, that for the maximum Tc, and that it increases by 0.015 per planar Cu ion for each increase of y by 0.01. Parameters of the model are taken to be the same as in a previous publication in which energy gaps were discussed, except that an effective hybridization parameter is adjusted for each Zn concentration to give agreement with the observed Tc. Results are presented for y = 0.0, 0.01, and 0.03. The agreement with experiment is good for thermodynamic critical fields, and is fair for specific heats. For specimens with larger y, with relatively low T(c)s, it is argued that the model should be supplemented to include effects of a BCS-type interaction amongst the wideband carriers.

  18. Assessment of Myocardial Remodeling Using an Elastin/Tropoelastin Specific Agent with High Field Magnetic Resonance Imaging (MRI)

    PubMed Central

    Protti, Andrea; Lavin, Begoña; Dong, Xuebin; Lorrio, Silvia; Robinson, Simon; Onthank, David; Shah, Ajay M; Botnar, Rene M

    2015-01-01

    Background Well-defined inflammation, proliferation, and maturation phases orchestrate the remodeling of the injured myocardium after myocardial infarction (MI) by controlling the formation of new extracellular matrix. The extracellular matrix consists mainly of collagen but also fractions of elastin. It is thought that elastin is responsible for maintaining elastic properties of the myocardium, thus reducing the risk of premature rupture. An elastin/tropoelastin–specific contrast agent (Gd-ESMA) was used to image tropoelastin and mature elastin fibers for in vivo assessment of extracellular matrix remodeling post-MI. Methods and Results Gd-ESMA enhancement was studied in a mouse model of myocardial infarction using a 7 T MRI scanner and results were compared to those achieved after injection of a nonspecific control contrast agent, gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). In the infarcted tissue, Gd-ESMA uptake (measured as R1 relaxation rate) steadily increased from day 3 to day 21 as a result of the synthesis of elastin/tropoelastin. R1 values were in good agreement with histological findings. A similar R1 behavior was observed in the remote myocardium. No mature cross-linked elastin was found at any time point. In contrast, Gd-DTPA uptake was only observed in the infarct with no changes in R1 values between 3 and 21 days post-MI. Conclusions We demonstrate the feasibility of in vivo imaging of extracellular matrix remodeling post-MI using a tropoelastin/elastin binding MR contrast agent, Gd-ESMA. We found that tropoelastin is the main contributor to the increased MRI signal at late stages of MI where its augmentation in areas of infarction was in good agreement with the R1 increase. PMID:26272655

  19. Reliability and Validity of a New Specific Field Test of Aerobic Capacity with the Ball for Futsal Players.

    PubMed

    Barbieri, Ricardo; Barbieri, Fabio; Milioni, Fabio; Dos-Santos, Julio; Soares, Marcelo; Zagatto, Alessandro; Papoti, Marcelo

    2017-03-01

    The aim of this study was to establish the validity and reliability and verification of the reproducibility of the lactate minimum test (LM) to predict the maximal lactate steady state exercise intensity (MLSS) on a futsal-specific circuit (Futsal_circuit) which takes into consideration the technical movements performed. 16 male Brazilian futsal players (body mass: 67.7±8.3 kg; height: 1.73±0.05 m) were distributed randomly into 2 studies with 8 athletes in each (Study A - reproducibility; Study B - validity). First, aerobic capacity was determined by adapting the protocol of the LM to the futsal_circuit. In study A, the evaluation was repeated after 7 days (test e re-test) and, in study B, the MLSS on the futsal_circuit was performed. LM intensity (test=7.7±0.3 km.h(-1); retest=7.7±0.4 km.h(-1)) showed a concordance (CV=4.13 and ET=0.32) on study A. No significant differences, high association (r=0.80; p<0.05) and concordance (lower limits: -0.58 km.h(-1); Upper limits: 0.55 km.h(-1)) between LM and MLSS (7.5±0.5 km.h(-1) LM; 7.5±0.4 km.h(-1) MLSS) on study B. According to the results, we can conclude that the Futsal_circuit is reliable, reproducible and valid for assessing the functional aerobic capacity of futsal players.

  20. Conformational state-specific free energy differences by one-step perturbation: protein secondary structure preferences of the GROMOS 43A1 and 53A6 force fields.

    PubMed

    Lin, Zhixiong; Van Gunsteren, Wilfred F; Liu, Haiyan

    2011-07-30

    The one-step free energy perturbation approach can be applied to obtain conformational state-specific free energy differences (FEDs) associated with changes in force field parameters, and thus offers the possibility to consider conformational equilibria during force field parameterization. In this work, using the alanine decapeptide in explicit water solution as a model, the α-helical and β-hairpin state-specific FEDs associated with force field changes between two widely used parameter sets of the GROMOS force field, namely, 43A1 and 53A6, were determined using one-step perturbation. The results mostly deviated by only 1 kJ mol(−1) in absolute or a few percent in relative values from thermodynamic integration results, suggesting that the convergence ranges of one-step perturbation were large enough to cover the substantial changes in nonbonded parameters between the two parameter sets. It was also found that one-step perturbation may give larger errors when the changes from the reference state include a large decrease in van der Waals radius, as indicated by the result for the β-hairpin state-specific free energy change going from 53A6 to 43A1. According to the free energy results, the α-helical state of the alanine decapeptide is destabilized by 15 kJ mol(−1), i.e., 1.5 kJ mol(−1) per residue, relative to the β-hairpin state when going from 43A1 to 53A6, in agreement with previous direct simulations in which native α-helices were often found to be unstable in simulations using 53A6, despite that the 53A6 parameters better reproduce a range of thermodynamic properties of small molecular systems. By applying one-step perturbation to analyze the effects of perturbing individual parameters, the differential stabilization of the two secondary structure states can be traced to the changes in van der Waals parameters, especially a van der Waals parameter involved in third-neighbor interactions. This study provides an example of the efficiency of one

  1. Communication: An efficient approach to compute state-specific nuclear gradients for a generic state-averaged multi-configuration self consistent field wavefunction

    SciTech Connect

    Granovsky, Alexander A.

    2015-12-21

    We present a new, very efficient semi-numerical approach for the computation of state-specific nuclear gradients of a generic state-averaged multi-configuration self consistent field wavefunction. Our approach eliminates the costly coupled-perturbed multi-configuration Hartree-Fock step as well as the associated integral transformation stage. The details of the implementation within the Firefly quantum chemistry package are discussed and several sample applications are given. The new approach is routinely applicable to geometry optimization of molecular systems with 1000+ basis functions using a standalone multi-core workstation.

  2. Specific Heat vs Field in the 30 K Superconductor BaFe2(As0.7P0.3)2

    NASA Astrophysics Data System (ADS)

    Stewart, G. R.; Kim, J. S.; Hirschfeld, P. J.; Kasahara, S.; Shibauchi, T.; Terashima, T.; Matsuda, Y.

    2010-03-01

    Recently, superconductivity at 30 K has been reported [1] in P-doped BaFe2As2, with 1/3 of the As replaced by P. Magnetic penetration and thermal conductivity measurements [2] indicate a nodally gapped superconductor. We report here on measurements of the specific heat divided by temperature, C/T, as a function of field up to 15 T and down to 0.4 K in order to further investigate the nodal structure with another probe. [4pt] [1] S. Kasahara, et al., arXiv0905.4427. [0pt] [2] K. Hashimoto, et al., arXiv0907.4399.

  3. Electronic properties of UX{sub 3} (X=Ga, Al, and Sn) compounds in high magnetic fields: Transport, specific heat, magnetization, and quantum oscillations

    SciTech Connect

    Cornelius, A.L.; Arko, A.J.; Sarrao, J.L.; Thompson, J.D.; Hundley, M.F.; Booth, C.H.; Harrison, N.; Oppeneer, P.M.

    1999-06-01

    We have performed measurements of the specific heat and resistivity in static magnetic fields up to 12 T, as well as magnetic measurements in a static field of 0.1 T and in pulsed fields up to 50 T on high-quality UX{sub 3} (X=Ga, Al, and Sn) single crystals. The behavior of the electronic specific heat coefficients in applied field {gamma}(B) either remains nearly constant or increases as {ital B} increases and is inconsistent with the expectations of the single-impurity model. For UGa{sub 3}, different de Haas{endash}van Alphen (dHvA) frequencies are observed above and below a magnetic transition at a field B{sub M}{approximately}12 T at T{approximately}0.5 K, indicating that a major reconstruction of the Fermi surface occurs. Neither USn{sub 3} nor UAl{sub 3} exhibited a magnetic transition in fields to 50 T, and only a single weak dHvA frequency was observed in these compounds. The difference between the behavior of the UX{sub 3} compounds can be attributed to the degree of hybridization of the 5f orbitals with the conduction electron orbitals. UGa{sub 3} behaves as an itinerant 5f-electron system, while UAl{sub 3} has a tendency to localization, but is still relatively delocalized. USn{sub 3} is a heavy fermion compound. Concurrent to our experimental investigations we have performed calculations of the energy band structures of the three compounds. Owing to the delocalized 5f behavior of UGa{sub 3}, and also of UAl{sub 3}, we find that an itinerant, energy band approach explains the dHvA frequencies of antiferromagnetic UGa{sub 3} and paramagnetic UAl{sub 3} reasonably well. For UGa{sub 3} an unusual sensitivity of the magnetic moment to the magnetic structure and the lattice parameter occurs, providing evidence that UGa{sub 3} is an unique example of an itinerant uranium-based antiferromagnet. thinsp {copyright} {ital 1999} {ital The American Physical Society}

  4. Frequency detection of imidacloprid resistance allele in Aphis gossypii field populations by real-time PCR amplification of specific-allele (rtPASA).

    PubMed

    Zhang, Jing; Cui, Li; Xu, Xibao; Rui, Changhui

    2015-11-01

    The Aphis gossypii Glover (Hemiptera: Aphididae) is one of the most serious pests worldwide, and imidacloprid has been widely used to control this insect pest. Just like other classes of insecticides, the resistance to imidacloprid has been found in A. gossypii. An amino acid mutation (R81T) in the nicotinic acetylcholine receptor (nAChR) beta1 subunit was detected in the imidacloprid-resistant A. gossypii collected from Langfang (LF) and Dezhou (DZ) cities. To estimate the R81T mutation frequency of A. gossypii field populations, a simple, rapid and accurate rtPASA (real-time PCR amplification of specific allele) protocol was developed. The performance of the rtPASA protocol was evaluated by comparing with the data generated by a cPASA (competitive PCR amplification of specific allele) method from 50 individual genotypes. The R81T allele frequencies of the LF population (34.7%±1.3%) and DZ population (45.2%±5.2%) estimated by the rtPASA protocol matched the frequencies (LF 38.1%, DZ 48.2%) deduced by the cPASA method in specimens. The results indicated that the rtPASA format was applicable for the detection of mutation associated with imidacloprid resistance and will allow rapid and efficient monitoring of A. gossypii resistance in field populations in a high throughput format.

  5. Sensitivity and specificity analysis of fringing-field dielectric spectroscopy applied to a multi-layer system modelling the human skin.

    PubMed

    Huclova, Sonja; Baumann, Dirk; Talary, Mark S; Fröhlich, Jürg

    2011-12-21

    The sensitivity and specificity of dielectric spectroscopy for the detection of dielectric changes inside a multi-layered structure is investigated. We focus on providing a base for sensing physiological changes in the human skin, i.e. in the epidermal and dermal layers. The correlation between changes of the human skin's effective permittivity and changes of dielectric parameters and layer thickness of the epidermal and dermal layers is assessed using numerical simulations. Numerical models include fringing-field probes placed directly on a multi-layer model of the skin. The resulting dielectric spectra in the range from 100 kHz up to 100 MHz for different layer parameters and sensor geometries are used for a sensitivity and specificity analysis of this multi-layer system. First, employing a coaxial probe, a sensitivity analysis is performed for specific variations of the parameters of the epidermal and dermal layers. Second, the specificity of this system is analysed based on the roots and corresponding sign changes of the computed dielectric spectra and their first and second derivatives. The transferability of the derived results is shown by a comparison of the dielectric spectra of a coplanar probe and a scaled coaxial probe. Additionally, a comparison of the sensitivity of a coaxial probe and an interdigitated probe as a function of electrode distance is performed. It is found that the sensitivity for detecting changes of dielectric properties in the epidermal and dermal layers strongly depends on frequency. Based on an analysis of the dielectric spectra, changes in the effective dielectric parameters can theoretically be uniquely assigned to specific changes in permittivity and conductivity. However, in practice, measurement uncertainties may degrade the performance of the system.

  6. Sensitivity and specificity analysis of fringing-field dielectric spectroscopy applied to a multi-layer system modelling the human skin

    NASA Astrophysics Data System (ADS)

    Huclova, Sonja; Baumann, Dirk; Talary, Mark S.; Fröhlich, Jürg

    2011-12-01

    The sensitivity and specificity of dielectric spectroscopy for the detection of dielectric changes inside a multi-layered structure is investigated. We focus on providing a base for sensing physiological changes in the human skin, i.e. in the epidermal and dermal layers. The correlation between changes of the human skin's effective permittivity and changes of dielectric parameters and layer thickness of the epidermal and dermal layers is assessed using numerical simulations. Numerical models include fringing-field probes placed directly on a multi-layer model of the skin. The resulting dielectric spectra in the range from 100 kHz up to 100 MHz for different layer parameters and sensor geometries are used for a sensitivity and specificity analysis of this multi-layer system. First, employing a coaxial probe, a sensitivity analysis is performed for specific variations of the parameters of the epidermal and dermal layers. Second, the specificity of this system is analysed based on the roots and corresponding sign changes of the computed dielectric spectra and their first and second derivatives. The transferability of the derived results is shown by a comparison of the dielectric spectra of a coplanar probe and a scaled coaxial probe. Additionally, a comparison of the sensitivity of a coaxial probe and an interdigitated probe as a function of electrode distance is performed. It is found that the sensitivity for detecting changes of dielectric properties in the epidermal and dermal layers strongly depends on frequency. Based on an analysis of the dielectric spectra, changes in the effective dielectric parameters can theoretically be uniquely assigned to specific changes in permittivity and conductivity. However, in practice, measurement uncertainties may degrade the performance of the system.

  7. Importance of material matching in the calibration of asymmetric flow field-flow fractionation: material specificity and nanoparticle surface coating effects on retention time

    NASA Astrophysics Data System (ADS)

    Qu, Haiou; Quevedo, Ivan R.; Linder, Sean W.; Fong, Andrew; Mudalige, Thilak K.

    2016-10-01

    Asymmetric flow field-flow fractionation (AF4) coupled with dynamic light scattering or multiangle light scattering detectors is a promising technique for the size-based separation of colloidal particles (nano- and submicron scale) and the online determination of the particle size of the separated fractions in aqueous suspensions. In most cases, the applications of these detectors are problematic due to the material-specific properties of the analyte that results in erroneous calculations, and as an alternative, different nanoparticle size standards are required to properly calibrate the size-based retention in AF4. The availability of nanoparticle size standards in different materials is limited, and this deviation from ideal conditions of retention is mainly due to material-specific and particle coating-specific membrane-particle interactions. Here, we present an experimental method on the applicability of polystyrene nanoparticles (PS NP) as standard for AF4 calibration and compare with gold nanoparticle (Au NP) standards having different nominal sizes and surface functionalities.

  8. Schaffer-specific local field potentials reflect discrete excitatory events at gamma frequency that may fire postsynaptic hippocampal CA1 units.

    PubMed

    Fernández-Ruiz, Antonio; Makarov, Valeri A; Benito, Nuria; Herreras, Oscar

    2012-04-11

    Information processing and exchange between brain nuclei are made through spike series sent by individual neurons in highly irregular temporal patterns. Synchronization in cell assemblies, proposed as a network language for internal neural representations, still has little experimental support. We use a novel technique to extract pathway-specific local field potentials (LFPs) in the hippocampus to explore the ongoing temporal structure of a single presynaptic input, the CA3 Schaffer pathway, and its contribution to the spontaneous output of CA1 units in anesthetized rat. We found that Schaffer-specific LFPs are composed of a regular succession of pulse-like excitatory packages initiated by spontaneous clustered firing of CA3 pyramidal cells to which individual units contribute variably. A fraction of these packages readily induce firing of CA1 pyramidal cells and interneurons, the so-called Schaffer-driven spikes, revealing the presynaptic origin in the output code of single CA1 units. The output of 70% of CA1 pyramidal neurons contains up to 10% of such spikes. Our results suggest a hierarchical internal operation of the CA3 region based on sequential oscillatory activation of pyramidal cell assemblies whose activity partly gets in the output code at the next station. We conclude that CA1 output may directly reflect the activity of specific ensembles of CA3 neurons. Thus, the fine temporal structure of pathway-specific LFPs, as an accurate readout of the activity of a presynaptic population, is useful in searching for hidden presynaptic code in irregular spikes series of individual neurons and assemblies.

  9. Sensitivity and specificity of Norwegian optometrists' evaluation of diabetic retinopathy in single-field retinal images - a cross-sectional experimental study.

    PubMed

    Sundling, Vibeke; Gulbrandsen, Pål; Straand, Jørund

    2013-01-10

    In the working age group, diabetic retinopathy is a leading cause of visual impairment. Regular eye examinations and early treatment of retinopathy can prevent visual loss, so screening for diabetic retinopathy is cost-effective. Dilated retinal digital photography with the additional use of ophthalmoscopy is the most effective and robust method of diabetic retinopathy screening. The aim of this study was to estimate the sensitivity and specificity of diabetic retinopathy screening when performed by Norwegian optometrists. This study employed a cross-sectional experimental design. Seventy-four optometrists working in private optometric practice were asked to screen 14 single-field retinal images for possible diabetic retinopathy. The screening was undertaken using a web-based visual identification and management of ophthalmological conditions (VIMOC) examination. The images used in the VIMOC examination were selected from a population survey and had been previously examined by two independent ophthalmologists. In order to establish a "gold standard", images were only chosen for use in the VIMOC examination if they had elicited diagnostic agreement between the two independent ophthalmologists. To reduce the possibility of falsely high specificity occurring by chance, half the presented images were of retinas that were not affected by diabetic retinopathy. Sensitivity and specificity for diabetic retinopathy was calculated with 95% confidence intervals (CIs). The mean (95%CI) sensitivity for identifying eyes with any diabetic retinopathy was 67% (62% to 72%). The mean (95%CI) specificity for identifying eyes without diabetic retinopathy was 84% (80% to 89%). The mean (95%CI) sensitivity for identifying eyes with mild non-proliferative diabetic retinopathy or moderate non-proliferative diabetes was 54% (47% to 61%) and 100%, respectively. Only four optometrists (5%) met the required standard of at least 80% sensitivity and 95% specificity that has been previously set

  10. Supramodal Theta, Gamma, and Sustained Fields Predict Modality-specific Modulations of Alpha and Beta Oscillations during Visual and Tactile Working Memory.

    PubMed

    van Ede, Freek; Jensen, Ole; Maris, Eric

    2017-03-30

    Flexible control over currently relevant sensory representations is an essential feature of primate cognition. We investigated the neurophysiological bases of such flexible control in humans during an intermodal working memory task in which participants retained visual or tactile sequences. Using magnetoencephalography, we first show that working memory retention engages early visual and somatosensory areas, as reflected in the sustained load-dependent suppression of alpha and beta oscillations. Next, we identify three components that are also load dependent but modality independent: medial prefrontal theta synchronization, frontoparietal gamma synchronization, and sustained parietal event-related fields. Critically, these domain-general components predict (across trials and within load conditions) the modality-specific suppression of alpha and beta oscillations, with largely unique contributions per component. Thus, working memory engages multiple complementary frontoparietal components that have discernible neuronal dynamics and that flexibly modulate retention-related activity in sensory areas in a manner that tracks the current contents of working memory.

  11. Channel-specific photoelectron angular distribution in laboratory and molecular frames for dissociative ionization of methanol in intense ultraviolet laser fields

    NASA Astrophysics Data System (ADS)

    Fukahori, Shinichi; Nakano, Motoyoshi; Yamanouchi, Kaoru; Itakura, Ryuji

    2017-03-01

    We investigate dissociative ionization of CH3OH in an intense laser field (398 nm, 76 fs, 8.9 × 1012 W/cm2) by photoelectron-photoion coincidence momentum imaging. It is revealed from the analysis of the channel-specific photoelectron angular distributions that CH3OH is decomposed into CH2OH+ + H after the four-photon ionization to the vibrationally highly excited states of the electronic ground state of CH3OH+ and into CH3+ + OH after the five-photon ionization to the second electronically excited state of CH3OH+, and that these two channels are also opened after CH3OH+, prepared by the four-photon ionization, is photoexcited further into the electronically excited states.

  12. How accurately can subject-specific finite element models predict strains and strength of human femora? Investigation using full-field measurements.

    PubMed

    Grassi, Lorenzo; Väänänen, Sami P; Ristinmaa, Matti; Jurvelin, Jukka S; Isaksson, Hanna

    2016-03-21

    Subject-specific finite element models have been proposed as a tool to improve fracture risk assessment in individuals. A thorough laboratory validation against experimental data is required before introducing such models in clinical practice. Results from digital image correlation can provide full-field strain distribution over the specimen surface during in vitro test, instead of at a few pre-defined locations as with strain gauges. The aim of this study was to validate finite element models of human femora against experimental data from three cadaver femora, both in terms of femoral strength and of the full-field strain distribution collected with digital image correlation. The results showed a high accuracy between predicted and measured principal strains (R(2)=0.93, RMSE=10%, 1600 validated data points per specimen). Femoral strength was predicted using a rate dependent material model with specific strain limit values for yield and failure. This provided an accurate prediction (<2% error) for two out of three specimens. In the third specimen, an accidental change in the boundary conditions occurred during the experiment, which compromised the femoral strength validation. The achieved strain accuracy was comparable to that obtained in state-of-the-art studies which validated their prediction accuracy against 10-16 strain gauge measurements. Fracture force was accurately predicted, with the predicted failure location being very close to the experimental fracture rim. Despite the low sample size and the single loading condition tested, the present combined numerical-experimental method showed that finite element models can predict femoral strength by providing a thorough description of the local bone mechanical response. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Polarizable QM/MM Multiconfiguration Self-Consistent Field Approach with State-Specific Corrections: Environment Effects on Cytosine Absorption Spectrum.

    PubMed

    Li, Quansong; Mennucci, Benedetta; Robb, Michael A; Blancafort, Lluís; Curutchet, Carles

    2015-04-14

    We present the formulation and implementation of a polarizable quantum mechanics/molecular mechanics (QM/MM) strategy to describe environment effects in multiconfiguration self-consistent field calculations. The strategy is applied to the calculation of the vertical absorption spectrum of cytosine in water. In our approach, mutual polarization of the solute and the solvent is solved self-consistently at the complete-active-space self-consistent-field (CASSCF) level, and the resulting set of charges and dipoles is used to calculate vertical excitation energies using the complete-active-space second-order perturbative (CASPT2) approach and its multistate (MS-CASPT2) variant. In order to treat multiple excited states, we converge the solvent polarization with respect to the state-averaged density of the solute. In order to obtain the final energies, however, we introduce a state-specific correction, where the solvent polarization is recomputed with the density of each state, and demonstrate that this correction brings the excitation energies closer to the values obtained with state-optimized orbitals. Comparison with PCM and nonpolarizable QM/MM calculations shows the importance of specific solute-solvent interactions and environment polarization in describing experiments. Overall, the calculated excitations for the π → π* states in water show good agreement with the experimental spectrum, whereas the n → π* appear at energies above 6 eV, approximately 1 eV higher than in the gas phase. Beyond solvents, the new method will allow studying the impact of heterogeneous biological environments in multiple excited states, as well as the treatment of multichromophoric systems where charge transfer and exciton states play important roles.

  14. Characterization of BoHV-5 field strains circulation and report of transient specific subtype of bovine herpesvirus 5 in Argentina

    PubMed Central

    2011-01-01

    Background Bovine herpesvirus 5 (BoHV-5) is a member of the subfamily Alphaherpesvirinae responsible for meningo-encephalitis in young cattle. The first case of bovine meningo-encephalitis associated with a herpesvirus infection was reported in Australia. The current geographical distribution of BoHV-5 infection is mainly restricted to South America, especially Brazil and Argentina. Outbreaks of BoHV-5 are regularly observed in Argentina suggesting the circulation of the virus in the bovine population. Results Seventeen field strains of BoHV-5 isolated from 1984 to now were confirmed by differential PCR and subjected to restriction endonuclease analysis (REA). Viral DNA was cleaved with BstEII which allows the differentiation among subtypes a, b and non a, non b. According to the REA with BstEII, only one field strain showed a pattern similar to the Argentinean A663 strain (prototype of BoHV-5b). All other isolates showed a clear pattern similar to the Australian N569 strain (prototype of BoHV-5a) consistent with the subtypes observed in Brazil, the other South-American country where BoHV-5 is known to be prevalent. The genomic region of subtype b responsible for the distinct pattern was determined and amplified by PCR; specifically a point mutation was identified in glycoprotein B gene, on the BstEII restriction site, which generates the profile specific of BoHV-5b. Conclusions This is the first report of circulation of BoHV-5a in Argentina as the prevailing subtype. Therefore the circulation of BoHV-5b was restricted to a few years in Argentina, speculating that this subtype was not able to be maintained in the bovine population. The mutation in the gB gene is associated with the difference in the restriction patterns between subtypes "a" and "b". PMID:21299866

  15. A novel field transplantation technique reveals intra-specific metal-induced oxidative responses in strains of Ectocarpus siliculosus with different pollution histories.

    PubMed

    Sáez, Claudio A; González, Alberto; Contreras, Rodrigo A; Moody, A John; Moenne, Alejandra; Brown, Murray T

    2015-04-01

    A novel field transplantation technique, in which seaweed material is incorporated into dialysis tubing, was used to investigate intra-specific responses to metals in the model brown alga Ectocarpus siliculosus. Metal accumulation in the two strains was similar, with higher concentrations in material deployed to the metal-contaminated site (Ventanas, Chile) than the pristine site (Quintay, Chile). However, the oxidative responses differed. At Ventanas, strain Es147 (from low-polluted site) underwent oxidative damage whereas Es524 (from highly polluted site) was not affected. Concentrations of reduced ascorbate (ASC) and reduced glutathione (GSH) were significantly higher in Es524. Activities of the antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and glutathione reductase (GR) all increased in Es524, whereas only SOD increased in Es147. For the first time, employing a field transplantation technique, we provide unambiguous evidence of inter-population variation of metal-tolerance in brown algae and establish that antioxidant defences are, in part, responsible.

  16. Field-wide meta-analyses of observational associations can map selective availability of risk factors and the impact of model specifications

    PubMed Central

    Serghiou, Stylianos; Patel, Chirag J.; Tan, Yan Yu; Koay, Peter; Ioannidis, John P.A.

    2016-01-01

    Objectives Instead of evaluating one risk factor at a time, we illustrate the utility of “field-wide meta-analyses” in considering all available data on all putative risk factors of a disease simultaneously. Study Design and Setting We identified studies on putative risk factors of pterygium (surfer’s eye) in PubMed, EMBASE, and Web of Science. We mapped which factors were considered, reported, and adjusted for in each study. For each putative risk factor, four meta-analyses were done using univariate only, multivariate only, preferentially univariate, or preferentially multivariate estimates. Results A total of 2052 records were screened to identify 60 eligible studies reporting on 65 putative risk factors. Only 4 of 60 studies reported both multivariate and univariate regression analyses. None of the 32 studies using multivariate analysis adjusted for the same set of risk factors. Effect sizes from different types of regression analyses led to significantly different summary effect sizes (P-value < 0.001). Observed heterogeneity was very high for both multivariate (median I2, 76.1%) and univariate (median I2, 85.8%) estimates. No single study investigated all 11 risk factors that were statistically significant in at least one of our meta-analyses. Conclusion Field-wide meta-analyses can map availability of risk factors and trends in modeling, adjustments and reporting, as well as the impact of differences in model specification. PMID:26415577

  17. SU-E-T-746: The Use of Radiochromic Film Analyzed with Three Channel Dosimetry as a Secondary Patient-Specific QA Tool for Small SBRT Fields

    SciTech Connect

    Hadsell, M; Holcombe, C; Chin, E; Hsu, A

    2015-06-15

    Introduction: As diagnostic techniques become more sensitive and targeting methods grow in accuracy, target volumes continue to shrink and SBRT becomes more prevalent. Due to this fact, patient-specific QA must also enhance resolution and accuracy in order to verify dose delivery in these volumes. It has been suggested that when measuring small fields at least two separate detectors be used to verify delivered dose. Therefore, we have instituted a secondary patient QA verification for small (<3cm) SBRT fields using Gafchromic EBT2 film. Methods: Films were cross-calibrated using a Farmer chamber in plastic water at reference conditions as defined by TG-51. Films were scanned, and an RGB calibration curve was created according to best practices published by Ashland, Inc. Four SBRT cases were evaluated both with the Scandidos Delta4 and with EBT2 films sandwiched in plastic water. Raw values obtained from the film were converted to dose using an in-house algorithm employing all three color channels to increase accuracy and dosimetric range. Gamma and dose profile comparisons to Eclipse dose calculations were obtained using RIT and compared to values obtained with the Delta4. Results: Film gamma pass rates at 2% and 2mm were similar to those obtained with the Delta4. However, dose difference histograms showed better absolute dose agreement, with the average mean film dose agreeing with calculation to 0.3% and the Delta4 only agreeing to 3.1% across the cases. Additionally, films provided more resolution than the Delta4 and thus their dose profiles better succeeded in diagnosing dose calculation inaccuracies. Conclusion: We believe that the implementation of secondary patient QA using EBT2 film analyzed with all three color channels is an invaluable tool for evaluation of small SBRT fields. Furthermore, we have shown that this method can sometimes provide a more detailed and faithful reproduction of plan dose than the Delta4.

  18. The effect of influence quantities and detector orientation on small-field patient-specific IMRT QA: comparison of measurements with various ionization chambers.

    PubMed

    Godson, Henry Finlay; Manickam, Ravikumar; Saminathan, Sathiyan; Ganesh, Kadirampatti Mani; Ponmalar, Retna

    2017-06-01

    Intensity-modulated radiation therapy (IMRT) requires a patient-specific quality assurance (QA) program to validate the treatment plan and a high level of dosimetric accuracy in the treatment delivery. Dosimetric verification generally consists of both absolute- and relative-dose measurements in a phantom using ionization chambers. Measurements were carried out with three different ionization chambers (Scanditronix FC 65G, Exradin A18, and PTW PinPoint 31014) to assess the effects of influence quantities such as the stability, pre- and post-irradiation leakage, stem effect, polarity, and ion recombination on the IMRT point-dose verification with two different orientations. The Exradin A18 and PTW PinPoint ion chambers demonstrated noticeable leakage to magnitudes of 0.6 and 1.2%, whereas negligible leakage was observed with FC 65G ion chamber. Maximum deviations of 0.5 and 0.6% were noticed for the smallest field owing to the ion recombination effect with the PTW PinPoint ion chamber in the parallel and perpendicular orientations, respectively. The calculated total uncertainties of all influence quantities for the FC 65G, A18, and PTW PinPoint ion chambers were 0.5, 0.7, and 1.3%, respectively. The uncertainties determined for each chamber were incorporated into the point-dose measurements of 30 head and neck patient-specific QA plans, and the variation was found to be within ±3%. The magnitude of the leakage in a small-volume ion chamber indicated the significance of incorporating the correction factors in the absolute-dose measurement. A paired t test analysis indicated that the influence quantities significantly affect the point-dose measurements in the patient-specific IMRT QA.

  19. Open-field host specificity test of Gratiana boliviana (Coleoptera: Chrysomelidae), a biological control agent of tropical soda apple (Solanaceae) in the United States

    SciTech Connect

    Gandolfo, D.; McKay, F.; Medal, J.C.; Cuda, J.P.

    2007-03-15

    An open-field experiment was conducted to assess the suitability of the South American leaf feeding beetle Gratiana boliviana Spaeth for biological control of Solanum viarum Dunal in the USA. An open-field test with eggplant, Solanum melongena L., was conducted on the campus of the University of Buenos Aires, Argentina, and a S. viarum control plot was established 40 km from the campus. One hundred adult beetles were released in each plot at the beginning of the experiment during the vegetative stage of the plants, and forty additional beetles were released in the S. melongena plot at the flowering stage. All the plants in each plot were checked twice a week and the number of adults, immatures, and eggs recorded. Results showed almost a complete rejection of eggplant by G. boliviana. No noticeable feeding damage was ever recorded on eggplant. The experiment was ended when the eggplants started to senesce or were severely damaged by whiteflies and spider mites. The results of this open-field experiment corroborate previous quarantine/laboratory host-specificity tests indicating that a host range expansion of G. boliviana to include eggplant is highly unlikely. Gratiana boliviana was approved for field release in May 2003 in the USA. To date, no non-target effects have been observed either on eggplant or native species of Solanum. (author) [Spanish] Una prueba de campo fue conducida para evaluar la especificidad del escarabajo suramericano defoliador Gratiana boliviana Spaeth para control biologico de Solanum viarum Dunal en los Estados Unidos. La prueba con berenjena se realizo en el campo experimental de la Universidad de Buenos Aires, Argentina, y una parcela control con S. viarum fue establecida a 40 km. Cien escarabajos adultos fueron liberados en cada parcela al inicio del experimento durante la fase vegetativa, y cuarenta escarabajos adicionales fueron liberados en la parcela de berenjena durante la floracion. Todas las plantas en cada parcela fueron

  20. Regional and field-specific factors affect the composition of fusarium head blight pathogens in subtropical no-till wheat agroecosystem of Brazil.

    PubMed

    Del Ponte, Emerson M; Spolti, Piérri; Ward, Todd J; Gomes, Larissa B; Nicolli, Camila P; Kuhnem, Paulo R; Silva, Cleiltan N; Tessmann, Dauri J

    2015-02-01

    A multiyear survey of >200 wheat fields in Paraná (PR) and Rio Grande do Sul (RS) states was conducted to assess the extent and distribution of Fusarium graminearum species complex (FGSC) diversity in the southern Brazilian wheat agroecosystem. Five species and three trichothecene genotypes were found among 671 FGSC isolates from Fusarium head blight (FHB)-infected wheat heads: F. graminearum (83%) of the 15-acetyldeoxynivalenol (15-ADON) genotype, F. meridionale (12.8%) and F. asiaticum (0.4%) of the nivalenol (NIV) genotype, and F. cortaderiae (2.5%) and F. austroamericanum (0.9%) with either the NIV or the 3-ADON genotype. Regional differences in FGSC composition were observed, with F. meridionale and the NIV type being significantly (P<0.001) more prevalent in PR (>28%) than in RS (≤9%). Within RS, F. graminearum was overrepresented in fields below 600 m in elevation and in fields with higher levels of FHB incidence (P<0.05). Species composition was not significantly influenced by previous crop or the stage of grain development at sampling. Habitat-specific differences in FGSC composition were evaluated in three fields by characterizing a total of 189 isolates collected from corn stubble, air above the wheat canopy, and symptomatic wheat kernels. Significant differences in FGSC composition were observed among these habitats (P<0.001). Most strikingly, F. meridionale and F. cortaderiae of the NIV genotype accounted for the vast majority (>96%) of isolates from corn stubble, whereas F. graminearum with the 15-ADON genotype was dominant (>84%) among isolates from diseased wheat kernels. Potential differences in pathogenic fitness on wheat were also suggested by a greenhouse competitiveness assay in which F. graminearum was recovered at much higher frequency (>90%) than F. meridionale from four wheat varieties inoculated with an equal mixture of F. graminearum and F. meridionale isolates. Taken together, the data presented here suggest that FGSC composition and

  1. The specific features of gold ore provinces of the south of Siberia in a magnetic field at ground height and heights of flight of satellite Champ.

    NASA Astrophysics Data System (ADS)

    Litvinova, Tamara; Petrova, Alevtina

    2010-05-01

    The specific features of gold ore provinces of the south of Siberia in a magnetic field at ground height and heights of flight of satellite Champ. T.Litvinova -All-Russian Geological Research Institute (VSEGEI) A. Petrova - St. Petersburg, SPbF IZMIRAN, Russian Academy of Sciences, St. Petersburg For allocation of specific features known gold ore objects (Olimpiadninskoje, Suchoi Log, etc.) is executed the morphological analysis of the magnetic field received on materials of aeromagnetic data and satellite measurements at heights of 100 and 400 km. On the ground data on a map of magnetic anomalies of Russia of scale 1:2 500000 of 50 km on the extended structures crossing known gold ore deposits and promising ore units have been constructed geomagnetic and densitys sections up to depth. On geomagnetic and densitys sections to known large gold ore to deposits are dated deep synvertical the permeable zones described by a synlenticular -layered structure. Extended horizons of not magnetic formations are located on depths about 10, 12, 15-18, 30 and 40 km. On deep densitys sections reference sites ¬ the Suchoi Log, Olimpiadninskoje and Vodorazdelnoje ¬ is characterized by zones of inversion of density. Areas of the loosened breeds are dated to synvertical to deep zones of hydrothermal and fluid study of breeds inside which the loosened lenses in intervals of depths from 2 up to 5 km are formed, 8-13 km, 18-20 and 25-30 km of 35-40 km within the limits of the bottom bark. The analysis of a magnetic field has shown, that gold mineralization in researched region is dated for zones of long-living regional explosive infringements, to permeable terrigenous to thicknesses of depressions, to adjournment depression structures in units of crossing of tectonofluid zones of diagonal orientation. Terrigenous adjournment depression structures are shown on a geomagnetic section as the powerful deflections filled with low-magnetic thicknesses. These deflections are dated to

  2. Development of Site-Specific Mg(2+)-RNA Force Field Parameters: A Dream or Reality? Guidelines from Combined Molecular Dynamics and Quantum Mechanics Simulations.

    PubMed

    Casalino, Lorenzo; Palermo, Giulia; Abdurakhmonova, Nodira; Rothlisberger, Ursula; Magistrato, Alessandra

    2017-01-10

    The vital contribution of Mg(2+) ions to RNA biology is challenging to dissect at the experimental level. This calls for the integrative support of atomistic simulations, which at the classical level are plagued by limited accuracy. Indeed, force fields intrinsically neglect nontrivial electronic effects that Mg(2+) exerts on its surrounding ligands in varying RNA coordination environments. Here, we present a combined computational study based on classical molecular dynamics (MD) and Density Functional Theory (DFT) calculations, aimed at characterizing (i) the performance of five Mg(2+) force field (FF) models in RNA systems and (ii) how charge transfer and polarization affect the binding of Mg(2+) ions in different coordination motifs. As a result, a total of ∼2.5 μs MD simulations (100/200 ns for each run) for two prototypical Mg(2+)-dependent ribozymes showed remarkable differences in terms of populations of inner-sphere coordination site types. Most importantly, complementary DFT calculations unveiled that differences in charge transfer and polarization among recurrent Mg(2+)-RNA coordination motifs are surprisingly small. In particular, the charge of the Mg(2+) ions substantially remains constant through different coordination sites, suggesting that the common philosophy of developing site-specific Mg(2+) ion parameters is not in line with the physical origin of the Mg(2+)-RNA MD simulations inaccuracies. Overall, this study constitutes a guideline for an adept use of current Mg(2+) models and provides novel insights for the rational development of next-generation Mg(2+) FFs to be employed for atomistic simulations of RNA.

  3. Biosensor based on a silicon nanowire field-effect transistor functionalized by gold nanoparticles for the highly sensitive determination of prostate specific antigen.

    PubMed

    Presnova, Galina; Presnov, Denis; Krupenin, Vladimir; Grigorenko, Vitaly; Trifonov, Artem; Andreeva, Irina; Ignatenko, Olga; Egorov, Alexey; Rubtsova, Maya

    2017-02-15

    We have demonstrated label-free and real-time detection of prostate specific antigen (PSA) in human serum using silicon nanowire field effect transistors (NW FETs) with Schottky contacts (Si-Ti). The NW FETs were fabricated from SOI material using high-resolution e-beam lithography, thin film vacuum deposition and reactive-ion etching processes eliminating complicated processes of doping and thermal annealing. This allowed substantial simplifying the transistors manufacturing. A new method for covalent immobilization of half-fragments of antibodies on silicon modified by 3-glycidopropyltrimethoxysilane with thiol groups and 5nm gold nanoparticles (GNPs) was established. NW FETs functionalized by GNPs revealed extremely high pH sensitivity of 70mV/pH and enhanced electrical performance in the detection of antigen due to enhanced surface/volume ratio, favorable orientation of antibody active sites and approaching the source of the electric field close to the transistor surface. Si NWFETs were applied for quantitative detection of PSA in a buffer and human serum diluted 1/100. Response time was about 5-10s, and analysis time per sample was 1min. The limit of PSA detection was of 23fg/mL, concentration range of 23fg/mL-500ng/mL (7 orders of magnitude). The PSA concentrations determined by the NW FETs in serum were compared with well-established ELISA method. The results matched well with the correlation coefficient of 0.97. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. THE SPECTRAL ENERGY DISTRIBUTIONS OF z ∼ 8 GALAXIES FROM THE IRAC ULTRA DEEP FIELDS: EMISSION LINES, STELLAR MASSES, AND SPECIFIC STAR FORMATION RATES AT 650 MYR

    SciTech Connect

    Labbé, I.; Bouwens, R. J.; Franx, M.; Oesch, P. A.; Illingworth, G. D.; Magee, D.; González, V.; Trenti, M.; Van Dokkum, P. G.; Stiavelli, M.

    2013-11-10

    Using new ultradeep Spitzer/InfraRed Array Camera (IRAC) photometry from the IRAC Ultra Deep Field program, we investigate the stellar populations of a sample of 63 Y-dropout galaxy candidates at z ∼ 8, only 650 Myr after the big bang. The sources are selected from HST/ACS+WFC3/IR data over the Hubble Ultra Deep Field (HUDF), two HUDF parallel fields, and wide area data over the CANDELS/GOODS-South. The new Spitzer/IRAC data increase the coverage in [3.6] and [4.5] to ∼120h over the HUDF reaching depths of ∼28 (AB,1σ). The improved depth and inclusion of brighter candidates result in direct ≥3σ InfraRed Array Camera (IRAC) detections of 20/63 sources, of which 11/63 are detected at ≥5σ. The average [3.6]-[4.5] colors of IRAC detected galaxies at z ∼ 8 are markedly redder than those at z ∼ 7, observed only 130 Myr later. The simplest explanation is that we witness strong rest-frame optical emission lines (in particular [O III] λλ4959, 5007 + Hβ) moving through the IRAC bandpasses with redshift. Assuming that the average rest-frame spectrum is the same at both z ∼ 7 and z ∼ 8 we estimate a rest-frame equivalent width of contributing 0.56{sup +0.16}{sub -0.11} mag to the [4.5] filter at z ∼ 8. The corresponding W{sub Hα}=430{sup +160}{sub -110} Å implies an average specific star formation rate of sSFR=11{sub -5}{sup +11} Gyr{sup –1} and a stellar population age of 100{sub -50}{sup +100} Myr. Correcting the spectral energy distribution for the contribution of emission lines lowers the average best-fit stellar masses and mass-to-light ratios by ∼3 ×, decreasing the integrated stellar mass density to ρ{sup *}(z=8,M{sub UV}<-18)=0.6{sup +0.4}{sub -0.3}×10{sup 6} M{sub sun} Mpc{sup –3}.

  5. Identification and specific detection of a novel pseudomonadaceae cluster associated with soils from winter wheat plots of a long-term agricultural field experiment.

    PubMed

    Pesaro, Manuel; Widmer, Franco

    2006-01-01

    The genus Pseudomonas (sensu stricto) represents a group of microorganisms directly involved in functions conferring plant health. We performed a study in the DOK long-term agricultural field experiment on the basis of previously published Pseudomonas-selective PCR primers in order to investigate the community structure of the microbial groups defined by the target range of these primers. Three different agricultural management systems, i.e., conventional, biodynamic, and bio-organic, along with mineral and unfertilized controls were investigated, with each system planted with either winter wheat or a grass-clover ley. Amplified small-subunit rRNA gene fragments were analyzed using the genetic profiling techniques restriction fragment length polymorphism (RFLP) and denaturing gradient gel electrophoresis (DGGE), revealing distinct differences between soils planted with winter wheat and grass clover but only minor differences between the management systems. Phylogenetic analyses of 59 clone sequences retrieved from bio-organic and unfertilized systems identified sequences related to Pseudomonas fluorescens and a novel cluster termed Cellvibrio-related Pseudomonadaceae (CRP). The CRP clones were exclusively isolated from winter wheat soil samples and were responsible for the crop-specific differences observed in RFLP and DGGE profiles. New primers were designed for the amplification of CRP targets directly from soil DNA, yielding strong signals exclusively for winter wheat soils. We concluded that crop-associated CRP exist in agricultural soils and that genetic profiling followed by specific probe design represents a valuable approach for identification as well as sensitive and rapid monitoring of novel microbial groups in the environment.

  6. Identification and Specific Detection of a Novel Pseudomonadaceae Cluster Associated with Soils from Winter Wheat Plots of a Long-Term Agricultural Field Experiment

    PubMed Central

    Pesaro, Manuel; Widmer, Franco

    2006-01-01

    The genus Pseudomonas (sensu stricto) represents a group of microorganisms directly involved in functions conferring plant health. We performed a study in the DOK long-term agricultural field experiment on the basis of previously published Pseudomonas-selective PCR primers in order to investigate the community structure of the microbial groups defined by the target range of these primers. Three different agricultural management systems, i.e., conventional, biodynamic, and bio-organic, along with mineral and unfertilized controls were investigated, with each system planted with either winter wheat or a grass-clover ley. Amplified small-subunit rRNA gene fragments were analyzed using the genetic profiling techniques restriction fragment length polymorphism (RFLP) and denaturing gradient gel electrophoresis (DGGE), revealing distinct differences between soils planted with winter wheat and grass clover but only minor differences between the management systems. Phylogenetic analyses of 59 clone sequences retrieved from bio-organic and unfertilized systems identified sequences related to Pseudomonas fluorescens and a novel cluster termed Cellvibrio-related Pseudomonadaceae (CRP). The CRP clones were exclusively isolated from winter wheat soil samples and were responsible for the crop-specific differences observed in RFLP and DGGE profiles. New primers were designed for the amplification of CRP targets directly from soil DNA, yielding strong signals exclusively for winter wheat soils. We concluded that crop-associated CRP exist in agricultural soils and that genetic profiling followed by specific probe design represents a valuable approach for identification as well as sensitive and rapid monitoring of novel microbial groups in the environment. PMID:16391022

  7. Real-time and label-free detection of the prostate-specific antigen in human serum by a polycrystalline silicon nanowire field-effect transistor biosensor.

    PubMed

    Huang, Yu-Wen; Wu, Chung-Shu; Chuang, Cheng-Keng; Pang, See-Tong; Pan, Tung-Ming; Yang, Yuh-Shyong; Ko, Fu-Hsiang

    2013-08-20

    In this research, we used a polycrystalline silicon nanowire field-effect transistor (poly-Si NWFET) as a biosensor that employs the sidewall spacer technique instead of an expensive electron beam lithography method. When compared with commercial semiconductor processes, the sidewall spacer technique has the advantages of simplicity and low cost. In this study, we employed a novel poly-Si NWFET device for real-time, label-free, and ultrahigh-sensitivity detection of prostate-specific antigen (PSA) in human serum. Since serum proteome is very complex containing high levels of salts and other interfering compounds, we hereby developed a standard operating procedure for real-sample pretreatment to keep a proper pH value and ionic strength of the desalted serum and also utilized Tween 20 to serve as the passivation agent by surface modification on the NWFET to reduce nonspecific binding for medical diagnostic applications. We first modified 3-aminopropyltriethoxysilane on the surface of a poly-Si nanowire device followed by glutaraldehyde functionalization, and the PSA antibodies were immobilized on the aldehyde terminal. While PSA was prepared in the buffers to maintain an appropriate pH value and ionic strength, the results indicated that the sensor could detect trace PSA at less than 5 fg/mL in a microfluidic channel. The novel poly-Si NWFET is developed as a diagnostic platform for monitoring prostate cancer and predicting the risk of early biochemical relapse.

  8. Analysis of specific absorption rate and internal electric field in human biological tissues surrounding an air-core coil-type transcutaneous energy transmission transformer.

    PubMed

    Shiba, Kenji; Zulkifli, Nur Elina Binti; Ishioka, Yuji

    2017-06-01

    In this study, we analyzed the internal electric field E and specific absorption rate (SAR) of human biological tissues surrounding an air-core coil transcutaneous energy transmission transformer. Using an electromagnetic simulator, we created a model of human biological tissues consisting of a dry skin, wet skin, fat, muscle, and cortical bone. A primary coil was placed on the surface of the skin, and a secondary coil was located subcutaneously inside the body. The E and SAR values for the model representing a 34-year-old male subject were analyzed using electrical frequencies of 0.3-1.5 MHz. The transmitting power was 15 W, and the load resistance was 38.4 Ω. The results showed that the E values were below the International Commission on Non-ionizing Radiation Protection (ICNIRP) limit for the general public exposure between the frequencies of 0.9 and 1.5 MHz, and SAR values were well below the limit prescribed by the ICNIRP for the general public exposure between the frequencies of 0.3 and 1.2 MHz.

  9. Fungal biocatalyst activated by an electric field: Improved mass transfer and non-specificity for hydrocarbon degradation in an airlift bioreactor.

    PubMed

    Sánchez-Vázquez, Victor; Shirai, Keiko; González, Ignacio; Gutiérrez-Rojas, Mariano

    2017-09-05

    The combination of biological and electrochemical techniques enhances the bioremediation efficiency of treating oil-contaminated water. In this study a non-growing fungal whole cell biocatalyst (BC; Aspergillus brasiliensis attached to perlite) pretreated with an electric field (EF), was used to degrade a hydrocarbon blend (hexadecane-phenanthrene-pyrene; 100:1:1w/w) in an airlift bioreactor (ALB). During hydrocarbon degradation, all mass transfer resistances (internal and external) and sorption capacity were experimentally quantified. Internal mass transfer resistances were evaluated through BC effectiveness factor analysis as a function of the Thiele modulus (using first order reaction kinetics, assuming a spherical BC, five particle diameters). External (interfacial) mass transfer resistances were evaluated by kLa determination. EF pretreatment during BC production promoted surface changes in BC and production of an emulsifier protein in the ALB. The BC surface modifications enhanced the affinity for hydrocarbons, improving hydrocarbon uptake by direct contact. The resulting emulsion was associated with decreased internal and external mass transfer resistances. EF pretreatment effects can be summarized as: a combined uptake mechanism (direct contact dominant followed by emulsified form dominant) diminishing mass transfer limitations, resulting in a non-specific hydrocarbon degradation in blend. The pretreated BC is a good applicant for oil-contaminated water remediation. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. A new species of Demodex (Acari: Demodecidae) with data on topical specificity and topography of demodectic mites in the striped field mouse Apodemus agrarius (Rodentia: Muridae).

    PubMed

    Izdebska, Joanna N; Rolbiecki, Leszek

    2013-11-01

    This article describes morphological characteristics and the occurrence of Demodex gracilentus sp. nov., which was found in the striped field mouse Apodemus agrarius (Pallas, 1771) in the skin of vibrissae area. D. gracilentus occurred in 36.7% of the rodents examined. D. gracilentus is a relatively large representative of the genus (adult stages on average 292 microm in length), a slender, elongated body; characteristic feature of these mites are conical supracoxal spines on dorsal side of gnathosoma, palps with asymmetric, forked triple spines on palptarsus, and the presence of rhomboidal opisthosomal organ. So far, the occurrence of three specific representatives of the family Demodecidae has been demonstrated in A. agrarius: Demodex apodemi (Hirst, 1918) (= Demodex arvicolae apodemi Hirst, 1918), Demodex agrarii Bukva, 1994, and Demodex huttereri Mertens, Lukoschus et Nutting, 1983. The first one is related to common hair follicles, especially in the skin of the head, while the next one inhabits the external auditory meatus, and the last one occurs in the meibomian glands of the eyelids.

  11. Columnar specificity of microvascular oxygenation and blood flow response in primary visual cortex: evaluation by local field potential and spiking activity

    PubMed Central

    Wang, Zheng; Roe, Anna W

    2012-01-01

    The relation of cortical microcirculation, oxygen metabolism, and underlying neuronal network activity remains poorly understood. Anatomical distribution of cortical microvasculature and its relationship to cortical functional domains suggests that functional organizations may be revealed by mapping cerebral blood flow responses. However, there is little direct experimental evidence and a lack of electrophysiological evaluation. In this study, we mapped ocular-dominance columns in primary visual cortex (V1) of anesthetized macaques with capillary flow-based laser speckle contrast imaging and deoxyhemoglobin-based intrinsic optical imaging. In parallel, the local field potentials (LFPs) and spikes were recorded from a linear array of eight microelectrodes, carefully positioned into left and right eye columns in V1. We found differential activation maps of blood flow, after masking large superficial draining vessels, exhibited a column-like pattern similar as the oximetric maps. Both the activated spikes and γ-band LFP demonstrated corresponding eye preference, consistent with the imaging maps. Our results present direct support in favor of previous proposals that the regulation of microcirculation can be as fine as the submillimeter scale, suggesting that cortical vasculature is functionally organized at the columnar level in a manner appropriate for supplying energy demands of functionally specific neuronal populations. PMID:22027939

  12. Cell-type-specific sub- and suprathreshold receptive fields of layer 4 and layer 2/3 pyramids in rat primary visual cortex.

    PubMed

    Medini, P

    2011-09-08

    Connectivity of cortical pyramidal neurons is layer-specific in the primary visual cortex (V1) and this is thought to be reflected in different receptive field (RF) properties of layer 4 and layer 2/3 pyramidal neurons (L4Ps and L2/3Ps, respectively). However, it remains unclear how the two cell populations convert incoming visually driven synaptic inputs into action potential (AP) outputs. Here I compared postsynaptic potentials (PSPs) and AP responses of L4Ps and L2/3Ps in the binocular portion of rat V1 by intrinsic optical imaging (IOI)-targeted whole-cell recordings followed by anatomical identification and dendritic reconstructions. L2/3Ps had about 2-fold longer dendritic branches and a higher number of branch points and endings in their apical portions. Functionally, L2/3Ps had more hyperpolarized resting potentials and lower rates of spontaneous APs (medians: 0.07 vs. 0.60 AP/s). PSP responses to optimally oriented moving bars were comparable in terms of amplitude (16.0±0.9 vs. 17.3±1.1 mV for L2/3Ps and L4Ps, respectively), reliability and size of the RF. The modulated component of subthreshold responses of L4Ps to optimal sinusoidal drifting gratings was larger and their PSP onset latency in response to bars flashed in the cell's RF center were shorter (60 vs. 86 ms). In contrast to the similarities of PSP responses to moving bars, AP responses of L2/3Ps were more sparse (medians: 0.7 vs. 2.9 APs/stimulus passage), less reliable, but sharper in terms of angular size. Based on the differences of subthreshold inputs, I conclude that L4Ps may receive mostly thalamic inputs, whereas L2/3Ps may receive both thalamic and cortical inputs from layer 4. The comparable subthreshold responses to moving bars are converted by L2/3Ps into sparser but sharper AP outputs possibly by cell-type-specific AP-generating mechanisms or differences in visually driven inhibitory inputs.

  13. Induction of an adaptive response in human blood lymphocytes exposed to radiofrequency fields: influence of the universal mobile telecommunication system (UMTS) signal and the specific absorption rate.

    PubMed

    Zeni, Olga; Sannino, Anna; Romeo, Stefania; Massa, Rita; Sarti, Maurizio; Reddy, Abishek B; Prihoda, Thomas J; Vijayalaxmi; Scarfì, Maria Rosaria

    2012-08-30

    The induction of an adaptive response (AR) was examined in human peripheral blood lymphocytes exposed to non-ionizing radiofrequency fields (RF). Cells from nine healthy human volunteers were stimulated for 24h with phytohaemagglutinin and then exposed for 20h to an adaptive dose (AD) of a 1950MHz RF UMTS (universal mobile telecommunication system) signal used for mobile communications, at different specific absorption rates (SAR) of 1.25, 0.6, 0.3, and 0.15W/kg. This was followed by treatment of the cells at 48h with a challenge dose (CD) of 100ng/ml mitomycin C (MMC). Lymphocytes were collected at the end of the 72h total culture period. The cytokinesis-block method was used to record the frequency of micronuclei (MN) as genotoxicity end-point. When lymphocytes from six donors were pre-exposed to RF at 0.3W/kg SAR and then treated with MMC, these cells showed a significant reduction in the frequency of MN, compared with the cells treated with MMC alone; this result is indicative of induction of AR. The results from our earlier study indicated that lymphocytes that were stimulated for 24h, exposed for 20h to a 900MHz RF GSM (global system for mobile communication) signal at 1.25W/kg SAR and then treated with 100ng/ml MMC, also exhibited AR. These overall data suggest that the induction of AR depends on RF frequency, type of the signal and SAR. Further characterization of RF-induced AR is in progress.

  14. A Spaceborne Synthetic Aperture Radar Partial Fixed-Point Imaging System Using a Field- Programmable Gate Array—Application-Specific Integrated Circuit Hybrid Heterogeneous Parallel Acceleration Technique

    PubMed Central

    Li, Bingyi; Chen, Liang; Wei, Chunpeng; Xie, Yizhuang; Chen, He; Yu, Wenyue

    2017-01-01

    With the development of satellite load technology and very large scale integrated (VLSI) circuit technology, onboard real-time synthetic aperture radar (SAR) imaging systems have become a solution for allowing rapid response to disasters. A key goal of the onboard SAR imaging system design is to achieve high real-time processing performance with severe size, weight, and power consumption constraints. In this paper, we analyse the computational burden of the commonly used chirp scaling (CS) SAR imaging algorithm. To reduce the system hardware cost, we propose a partial fixed-point processing scheme. The fast Fourier transform (FFT), which is the most computation-sensitive operation in the CS algorithm, is processed with fixed-point, while other operations are processed with single precision floating-point. With the proposed fixed-point processing error propagation model, the fixed-point processing word length is determined. The fidelity and accuracy relative to conventional ground-based software processors is verified by evaluating both the point target imaging quality and the actual scene imaging quality. As a proof of concept, a field- programmable gate array—application-specific integrated circuit (FPGA-ASIC) hybrid heterogeneous parallel accelerating architecture is designed and realized. The customized fixed-point FFT is implemented using the 130 nm complementary metal oxide semiconductor (CMOS) technology as a co-processor of the Xilinx xc6vlx760t FPGA. A single processing board requires 12 s and consumes 21 W to focus a 50-km swath width, 5-m resolution stripmap SAR raw data with a granularity of 16,384 × 16,384. PMID:28672813

  15. A Spaceborne Synthetic Aperture Radar Partial Fixed-Point Imaging System Using a Field- Programmable Gate Array-Application-Specific Integrated Circuit Hybrid Heterogeneous Parallel Acceleration Technique.

    PubMed

    Yang, Chen; Li, Bingyi; Chen, Liang; Wei, Chunpeng; Xie, Yizhuang; Chen, He; Yu, Wenyue

    2017-06-24

    With the development of satellite load technology and very large scale integrated (VLSI) circuit technology, onboard real-time synthetic aperture radar (SAR) imaging systems have become a solution for allowing rapid response to disasters. A key goal of the onboard SAR imaging system design is to achieve high real-time processing performance with severe size, weight, and power consumption constraints. In this paper, we analyse the computational burden of the commonly used chirp scaling (CS) SAR imaging algorithm. To reduce the system hardware cost, we propose a partial fixed-point processing scheme. The fast Fourier transform (FFT), which is the most computation-sensitive operation in the CS algorithm, is processed with fixed-point, while other operations are processed with single precision floating-point. With the proposed fixed-point processing error propagation model, the fixed-point processing word length is determined. The fidelity and accuracy relative to conventional ground-based software processors is verified by evaluating both the point target imaging quality and the actual scene imaging quality. As a proof of concept, a field- programmable gate array-application-specific integrated circuit (FPGA-ASIC) hybrid heterogeneous parallel accelerating architecture is designed and realized. The customized fixed-point FFT is implemented using the 130 nm complementary metal oxide semiconductor (CMOS) technology as a co-processor of the Xilinx xc6vlx760t FPGA. A single processing board requires 12 s and consumes 21 W to focus a 50-km swath width, 5-m resolution stripmap SAR raw data with a granularity of 16,384 × 16,384.

  16. Two-spoke placement optimization under explicit specific absorption rate and power constraints in parallel transmission at ultra-high field

    NASA Astrophysics Data System (ADS)

    Dupas, Laura; Massire, Aurélien; Amadon, Alexis; Vignaud, Alexandre; Boulant, Nicolas

    2015-06-01

    The spokes method combined with parallel transmission is a promising technique to mitigate the B1+ inhomogeneity at ultra-high field in 2D imaging. To date however, the spokes placement optimization combined with the magnitude least squares pulse design has never been done in direct conjunction with the explicit Specific Absorption Rate (SAR) and hardware constraints. In this work, the joint optimization of 2-spoke trajectories and RF subpulse weights is performed under these constraints explicitly and in the small tip angle regime. The problem is first considerably simplified by making the observation that only the vector between the 2 spokes is relevant in the magnitude least squares cost-function, thereby reducing the size of the parameter space and allowing a more exhaustive search. The algorithm starts from a set of initial k-space candidates and performs in parallel for all of them optimizations of the RF subpulse weights and the k-space locations simultaneously, under explicit SAR and power constraints, using an active-set algorithm. The dimensionality of the spoke placement parameter space being low, the RF pulse performance is computed for every location in k-space to study the robustness of the proposed approach with respect to initialization, by looking at the probability to converge towards a possible global minimum. Moreover, the optimization of the spoke placement is repeated with an increased pulse bandwidth in order to investigate the impact of the constraints on the result. Bloch simulations and in vivo T2∗-weighted images acquired at 7 T validate the approach. The algorithm returns simulated normalized root mean square errors systematically smaller than 5% in 10 s.

  17. Si-N membrane microcalorimetry: Thermal conductivity and specific heat of thin films from 2-500K in magnetic fields to 8 Tesla.

    NASA Astrophysics Data System (ADS)

    Zink, Barry

    2003-03-01

    Understanding the thermal behavior of mesoscopic systems and thin films is a critical issue of both fundamental and technological solid state science. Despite the wealth of knowledge in principle available from accurate measurement of specific heat and thermal conductivity of thin films, there are relatively few results of this type, due to the difficulty of isolating the small heat capacities and thermal conductivities from the typically large background contribution of conventional apparatus. Our group at UC San Diego uses amorphous Si-N membranes to thermally isolate small samples from their environment and allow accurate thermal measurements. Recent work adds the ability to measure thermal conductivity of films as thin as 150 Angstrom over a broad temperature range [1] to our well-established techniques for measuring Cp of small samples.[2] Our microcalorimeter is also particularly well-suited for measurements of both Cp and k in high magnetic fields [3]. The micromachining techniques used to fabricate the calorimeter allow production of significant numbers of calorimeters with well-controlled dimensions and highly reproducible properties which facilitates studies of the thermal properties of thin film and tiny crystals. In this talk I will briefly review the fabrication of our microcalorimeter and the techniques for measuring Cp and k. I will present example data and results of numerical heat flow simulations used to further our understanding of heat flow in the microcalorimeter [1] B. L. Zink, B. Revaz, J. J. Cherry and F. Hellman, Submitted to RSI, Sept. 2002 [2] D. W. Denlinger et al., Rev. Sci. Inst 65, 946-59 (1994) [3] B. L. Zink, B. Revaz, R. Sappey and F. Hellman, Rev. Sci. Instrum. 73, 1841 (2002)

  18. High-order harmonic generation and above-threshold ionization in H: Calculations using expansions over field-free state-specific wave functions

    NASA Astrophysics Data System (ADS)

    Dionissopoulou, S.; Mercouris, Th.; Lyras, A.; Komninos, Y.; Nicolaides, C. A.

    1995-04-01

    We have computed the above-threshold ionization and the emitted harmonic spectra of H interacting with short laser pulses, with photon energies ranging from 1.16 to 5.44 eV and with peak intensities ranging from 6×1013 to 7×1014 W/cm2, by solving the time-dependent Schrödinger equation (TDSE). The method of solution involves the expansion of the time-dependent wave function Ψ(r-->,t) over the exact wave functions of the discrete and the continuous spectrum, computed numerically, and the subsequent integration of the resulting coupled first-order differential equations by a Taylor series expansion technique. This state-specific approach (SSA) to the solution of the TDSE allows systematic understanding of convergence as a function of the number and type of the field-free states for each value of the laser frequency (ω) and peak intensity (I0). For example, the method allows practical numerical study of the degree of participation of high (n,l) (l=0,1,...,n-1) Rydberg, as well as of high-energy scattering states for each partial wave. For the harmonic spectra, comparisons are made between the results obtained by the SSA and those obtained in recent years by a number of researchers from the application of finite-difference grid methods. As regards economy, a general observation is that in the SSA the necessary number of partial waves is smaller than that required in the grid methods. Predictions are made for the case of ħω=2 eV, I0=2×1014 W/cm2, in the context of a study of the effect of the pulse shape on the harmonic-generation spectrum. It is shown that the number of harmonics and the appearance of the plateau depend on the duration of the peak intensity.

  19. Ultra-low specific on-resistance high-voltage vertical double diffusion metal-oxide-semiconductor field-effect transistor with continuous electron accumulation layer

    NASA Astrophysics Data System (ADS)

    Da, Ma; Xiao-Rong, Luo; Jie, Wei; Qiao, Tan; Kun, Zhou; Jun-Feng, Wu

    2016-04-01

    A new ultra-low specific on-resistance (R on,sp) vertical double diffusion metal-oxide-semiconductor field-effect transistor (VDMOS) with continuous electron accumulation (CEA) layer, denoted as CEA-VDMOS, is proposed and its new current transport mechanism is investigated. It features a trench gate directly extended to the drain, which includes two PN junctions. In on-state, the electron accumulation layers are formed along the sides of the extended gate and introduce two continuous low-resistance current paths from the source to the drain in a cell pitch. This mechanism not only dramatically reduces the R on,sp but also makes the R on,sp almost independent of the n-pillar doping concentration (N n). In off-state, the depletion between the n-pillar and p-pillar within the extended trench gate increases the N n, and further reduces the R on,sp. Especially, the two PN junctions within the trench gate support a high gate-drain voltage in the off-state and on-state, respectively. However, the extended gate increases the gate capacitance and thus weakens the dynamic performance to some extent. Therefore, the CEA-VDMOS is more suitable for low and medium frequencies application. Simulation indicates that the CEA-VDMOS reduces the R on,sp by 80% compared with the conventional super-junction VDMOS (CSJ-VDMOS) at the same high breakdown voltage (BV). Project supported by the National Natural Science Foundation of China (Grant Nos. 61176069 and 61376079) and the Fundamental Research Funds for the Central Universities, China (Grant No. ZYGX2014Z006).

  20. Two-spoke placement optimization under explicit specific absorption rate and power constraints in parallel transmission at ultra-high field.

    PubMed

    Dupas, Laura; Massire, Aurélien; Amadon, Alexis; Vignaud, Alexandre; Boulant, Nicolas

    2015-06-01

    The spokes method combined with parallel transmission is a promising technique to mitigate the B1(+) inhomogeneity at ultra-high field in 2D imaging. To date however, the spokes placement optimization combined with the magnitude least squares pulse design has never been done in direct conjunction with the explicit Specific Absorption Rate (SAR) and hardware constraints. In this work, the joint optimization of 2-spoke trajectories and RF subpulse weights is performed under these constraints explicitly and in the small tip angle regime. The problem is first considerably simplified by making the observation that only the vector between the 2 spokes is relevant in the magnitude least squares cost-function, thereby reducing the size of the parameter space and allowing a more exhaustive search. The algorithm starts from a set of initial k-space candidates and performs in parallel for all of them optimizations of the RF subpulse weights and the k-space locations simultaneously, under explicit SAR and power constraints, using an active-set algorithm. The dimensionality of the spoke placement parameter space being low, the RF pulse performance is computed for every location in k-space to study the robustness of the proposed approach with respect to initialization, by looking at the probability to converge towards a possible global minimum. Moreover, the optimization of the spoke placement is repeated with an increased pulse bandwidth in order to investigate the impact of the constraints on the result. Bloch simulations and in vivo T2(∗)-weighted images acquired at 7 T validate the approach. The algorithm returns simulated normalized root mean square errors systematically smaller than 5% in 10 s. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Ferrous iron- and ammonium-rich diffuse vents support habitat-specific communities in a shallow hydrothermal field off the Basiluzzo Islet (Aeolian Volcanic Archipelago).

    PubMed

    Bortoluzzi, G; Romeo, T; La Cono, V; La Spada, G; Smedile, F; Esposito, V; Sabatino, G; Di Bella, M; Canese, S; Scotti, G; Bo, M; Giuliano, L; Jones, D; Golyshin, P N; Yakimov, M M; Andaloro, F

    2017-09-01

    Ammonium- and Fe(II)-rich fluid flows, known from deep-sea hydrothermal systems, have been extensively studied in the last decades and are considered as sites with high microbial diversity and activity. Their shallow-submarine counterparts, despite their easier accessibility, have so far been under-investigated, and as a consequence, much less is known about microbial communities inhabiting these ecosystems. A field of shallow expulsion of hydrothermal fluids has been discovered at depths of 170-400 meters off the base of the Basiluzzo Islet (Aeolian Volcanic Archipelago, Southern Tyrrhenian Sea). This area consists predominantly of both actively diffusing and inactive 1-3 meters-high structures in the form of vertical pinnacles, steeples and mounds covered by a thick orange to brown crust deposits hosting rich benthic fauna. Integrated morphological, mineralogical, and geochemical analyses revealed that, above all, these crusts are formed by ferrihydrite-type Fe(3+) oxyhydroxides. Two cruises in 2013 allowed us to monitor and sampled this novel ecosystem, certainly interesting in terms of shallow-water iron-rich site. The main objective of this work was to characterize the composition of extant communities of iron microbial mats in relation to the environmental setting and the observed patterns of macrofaunal colonization. We demonstrated that iron-rich deposits contain complex and stratified microbial communities with a high proportion of prokaryotes akin to ammonium- and iron-oxidizing chemoautotrophs, belonging to Thaumarchaeota, Nitrospira, and Zetaproteobacteria. Colonizers of iron-rich mounds, while composed of the common macrobenthic grazers, predators, filter-feeders, and tube-dwellers with no representatives of vent endemic fauna, differed from the surrounding populations. Thus, it is very likely that reduced electron donors (Fe(2+) and NH4(+) ) are important energy sources in supporting primary production in microbial mats, which form a habitat-specific

  2. The Spectral Energy Distributions of z ~ 8 Galaxies from the IRAC Ultra Deep Fields: Emission Lines, Stellar Masses, and Specific Star Formation Rates at 650 Myr

    NASA Astrophysics Data System (ADS)

    Labbé, I.; Oesch, P. A.; Bouwens, R. J.; Illingworth, G. D.; Magee, D.; González, V.; Carollo, C. M.; Franx, M.; Trenti, M.; van Dokkum, P. G.; Stiavelli, M.

    2013-11-01

    Using new ultradeep Spitzer/InfraRed Array Camera (IRAC) photometry from the IRAC Ultra Deep Field program, we investigate the stellar populations of a sample of 63 Y-dropout galaxy candidates at z ~ 8, only 650 Myr after the big bang. The sources are selected from HST/ACS+WFC3/IR data over the Hubble Ultra Deep Field (HUDF), two HUDF parallel fields, and wide area data over the CANDELS/GOODS-South. The new Spitzer/IRAC data increase the coverage in [3.6] and [4.5] to ~120h over the HUDF reaching depths of ~28 (AB,1σ). The improved depth and inclusion of brighter candidates result in direct >=3σ InfraRed Array Camera (IRAC) detections of 20/63 sources, of which 11/63 are detected at >=5σ. The average [3.6]-[4.5] colors of IRAC detected galaxies at z ~ 8 are markedly redder than those at z ~ 7, observed only 130 Myr later. The simplest explanation is that we witness strong rest-frame optical emission lines (in particular [O III] λλ4959, 5007 + Hβ) moving through the IRAC bandpasses with redshift. Assuming that the average rest-frame spectrum is the same at both z ~ 7 and z ~ 8 we estimate a rest-frame equivalent width of {W}_{[O\\,\\scriptsize{III}]\\ \\lambda \\lambda 4959,5007+H\\beta }=670^{+260}_{-170} Å contributing 0.56^{+0.16}_{-0.11} mag to the [4.5] filter at z ~ 8. The corresponding {W}_{H\\alpha }=430^{+160}_{-110} Å implies an average specific star formation rate of sSFR=11_{-5}^{+11} Gyr-1 and a stellar population age of 100_{-50}^{+100} Myr. Correcting the spectral energy distribution for the contribution of emission lines lowers the average best-fit stellar masses and mass-to-light ratios by ~3 ×, decreasing the integrated stellar mass density to \\rho ^*(z=8,M_{\\rm{UV}}<-18)=0.6^{+0.4}_{-0.3}\\times 10^6 \\,M_\\odot Mpc-3. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated

  3. Gamma-Ray Dose Measurement with Radio-Photoluminescence Glass Dosimeter in Mixed Radiation Field for BNCT

    NASA Astrophysics Data System (ADS)

    Hiramatsu, K.; Yoshihashi, S.; Kusaka, S.; Sato, F.; Hoashi, E.; Murata, I.

    2017-09-01

    Accelerator based neutron sources (ABNS) are being developed as the next generation neutron irradiation system for BNCT. From the ABNS, unnecessary gamma-rays will be generated by neutron capture reactions, as well as fast neutrons. To control the whole-body radiation dose to the patient, measurement of gamma-ray dose in the irradiation room is necessary. In this study, the objective is to establish a method to measure gamma-ray dose separately in a neutron/gamma mixed field by using RPL glass dosimeter. For this purpose, we proposed a lead filter method which uses a pair of RPL glasses with and without a lead filter outside. In order to realize this method, the basic characteristics of glass dosimeter was verified in the gamma-ray field, before adapting it in the mixture field. From the result of the experiment using the lead filter, the simulation result especially for the case with a lead filter overestimated the absorbed does obtained from measurement. We concluded that the reason of the discrepancy is caused by existence of gradient of the dose distribution in the glass, and the difference of sensitivity to low-energy photon between measurement and theory.

  4. Open-field host specificity test of Gratiana boliviana (Coleoptera:Chrysomelidae), a biological control agent of Tropical Soda Apple (Solanaceae) in the United States

    USDA-ARS?s Scientific Manuscript database

    An open-field experiment was conducted to asses the suitability of the South American leaf feeding beetle Gratiana boliviana Spaeth for biological control of Solanum viarum Dunal in the USA. An open-field test with eggplant, Solanum melongena L., was conducted on the campus of the University of Buen...

  5. Mastitis vaccination using a commercial polyvalent vaccine or a herd-specific Staphylococcus aureus vaccine. Results of a controlled field trial on a dairy farm.

    PubMed

    Freick, Markus; Frank, Yvonne; Steinert, Kathrin; Hamedy, Ahmad; Passarge, Oliver; Sobiraj, Axel

    2016-08-17

    Objective of this study was the improvement of selected parameters of udder health by mastitis vaccination in a dairy herd with elevated bulk milk somatic cell counts and Staphylococcus (S.) aureus as predominant mastitis causing pathogen. On a dairy farm, pregnant heifers (status group [SG] 1; n = 181) as well as cows stratified for their udder health state (classification based on results of cytobacteriological investigations of quarter milk samples obtained before dry cow therapy [MS0]) (SG 2-4; n = 416) were randomly assigned to one of the following vaccination groups (VG): Startvac® (VG SV), Bestvac® Rind Mastitis (containing herd-specific S. aureus-strains; VG BV) and the unvaccinated control (VG Co, placebo), respectively. The collected data (5 [MS5] and 52 [MS52] days in milk [DIM]: quarter milk somatic cell count [QSCC] and bacteriological investigation of quarter milk samples; dairy herd improvement test [DHIT] days 1-10: milk yield and individual cow somatic cell count; until 305 DIM: clinical mastitis cases) were compared between the VG within their SG. S. aureus prevalences were significantly lower in VG SV (p < 0.001) and VG BV (p = 0.006) within SG 3 and in VG SV (p = 0.008) within SG 4, respectively, in comparison to VG Co. Milk yields (DHIT days [p = 0.042] and 305-day milk yield [p = 0.040]) were significantly less in VG SV within SG 4 compared to VG Co. Significant different changes over time in comparison to VG Co indicating a vaccine effect during lactation were only observed for QSCC within SG 4 for VG BV (p = 0.017; increase towards MS52) and for S. aureus prevalence within SG 3 for VG BV (p < 0.001; opposing trends from MS0 towards MS52). All other interactions of time and VG under investigation were not significant in any of the SG. Furthermore, there were no descriptive differences in the incidence of clinical mastitis and duration of a necessary mastitis therapy, respectively, between the VG within

  6. Durability and Shielding Performance of Borated Ceramicrete Coatings in Gamma Radiation Fields

    SciTech Connect

    Wagh, Arun S.; Sayenko, S. Yu.; Dovbnya, A.N.; Shkuropatenko, V.A.; Tarasov, R.V.; Rybka, A.V.; Zakharchenko, A.A.

    2015-07-01

    Ceramicrete™, a chemically bonded phosphate ceramic, was developed for nuclear waste immobilization and nuclear radiation shielding. Ceramicrete products are fabricated by an acid–base reaction between magnesium oxide and mono potassium phosphate. Fillers are used to impart desired properties to the product. Ceramicrete’s tailored compositions have resulted in several commercial structural products, including corrosion- and fire-protection coatings. Their borated version, called Borobond™, has been studied for its neutron shielding capabilities and is being used in structures built for storage of nuclear materials. This investigation assesses the durability and shielding performance of borated Ceramicrete coatings when exposed to gamma and beta radiations to predict the composition needed for optimal shielding performance in a realistic nuclear radiation field. Investigations were conducted using experimental data coupled with predictive Monte Carlo computer model. The results show that it is possible to produce products for simultaneous shielding of all three types of nuclear radiations, viz., neutrons, gamma-, and beta-rays. Additionally, because sprayable Ceramicrete coatings exhibit excellent corrosionand fire-protection characteristics on steel, this research also establishes an opportunity to produce thick coatings to enhance the shielding performance of corrosion and fire protection coatings for use in high radiation environment in nuclear industry.

  7. Durability and shielding performance of borated Ceramicrete coatings in beta and gamma radiation fields

    NASA Astrophysics Data System (ADS)

    Wagh, Arun S.; Sayenko, S. Yu.; Dovbnya, A. N.; Shkuropatenko, V. A.; Tarasov, R. V.; Rybka, A. V.; Zakharchenko, A. A.

    2015-07-01

    Ceramicrete™, a chemically bonded phosphate ceramic, was developed for nuclear waste immobilization and nuclear radiation shielding. Ceramicrete products are fabricated by an acid-base reaction between magnesium oxide and mono potassium phosphate. Fillers are used to impart desired properties to the product. Ceramicrete's tailored compositions have resulted in several commercial structural products, including corrosion- and fire-protection coatings. Their borated version, called Borobond™, has been studied for its neutron shielding capabilities and is being used in structures built for storage of nuclear materials. This investigation assesses the durability and shielding performance of borated Ceramicrete coatings when exposed to gamma and beta radiations to predict the composition needed for optimal shielding performance in a realistic nuclear radiation field. Investigations were conducted using experimental data coupled with predictive Monte Carlo computer model. The results show that it is possible to produce products for simultaneous shielding of all three types of nuclear radiations, viz., neutrons, gamma-, and beta-rays. Additionally, because sprayable Ceramicrete coatings exhibit excellent corrosion- and fire-protection characteristics on steel, this research also establishes an opportunity to produce thick coatings to enhance the shielding performance of corrosion and fire protection coatings for use in high radiation environment in nuclear industry.

  8. Monte Carlo simulated correction factors for machine specific reference field dose calibration and output factor measurement using fixed and iris collimators on the CyberKnife system

    NASA Astrophysics Data System (ADS)

    Francescon, P.; Kilby, W.; Satariano, N.; Cora, S.

    2012-06-01

    Monte Carlo (MC) simulation of dose to water and dose to detector has been used to calculate the correction factors needed for dose calibration and output factor measurements on the CyberKnife system. Reference field ionization chambers simulated were the PTW 30006, Exradin A12, and NE 2571 Farmer chambers, and small volume chambers PTW 31014 and 31010. Correction factors for Farmer chambers were found to be 0.7%-0.9% larger than those determined from TRS-398 due mainly to the dose gradient across the chamber cavity. For one microchamber where comparison was possible, the factor was 0.5% lower than TRS-398 which is consistent with previous MC simulations of flattening filter free Linacs. Output factor detectors simulated were diode models PTW 60008, 60012, 60017, 60018, Sun Nuclear edge detector, air-filled microchambers Exradin A16 and PTW 31014, and liquid-filled microchamber PTW 31018 microLion. Factors were generated for both fixed and iris collimators. The resulting correction factors differ from unity by up to +11% for air-filled microchambers and -6% for diodes at the smallest field size (5 mm), and tend towards unity with increasing field size (correction factor magnitude <1% for all detectors at field sizes >15 mm). Output factor measurements performed using these detectors with fixed and iris collimators on two different CyberKnife systems showed initial differences between detectors of >15% at 5 mm field size. After correction the measurements on each unit agreed within ˜1.5% at the smallest field size. This paper provides a complete set of correction factors needed to apply a new small field dosimetry formalism to both collimator types on the CyberKnife system using a range of commonly used detectors.

  9. Neutron Reference Benchmark Field Specification: ACRR 44 Inch Lead-Boron (LB44) Bucket Environment (ACRR-LB44-CC-32-CL).

    SciTech Connect

    Vega, Richard Manuel; Parma, Edward J.; Griffin, Patrick J.; Vehar, David W.

    2015-07-01

    This report was put together to support the International Atomic Energy Agency (IAEA) REAL- 2016 activity to validate the dosimetry community’s ability to use a consistent set of activation data and to derive consistent spectral characterizations. The report captures details of integral measurements taken in the Annular Core Research Reactor (ACRR) central cavity with the 44 inch Lead-Boron (LB44) bucket, reference neutron benchmark field. The field is described and an “a priori” calculated neutron spectrum is reported, based on MCNP6 calculations, and a subject matter expert (SME) based covariance matrix is given for this “a priori” spectrum. The results of 31 integral dosimetry measurements in the neutron field are reported.

  10. Impact of a product-specific reference standard for the measurement of a PEGylated rFVIII activity: the Swiss Multicentre Field Study.

    PubMed

    Bulla, O; Poncet, A; Alberio, L; Asmis, L M; Gähler, A; Graf, L; Nagler, M; Studt, J-D; Tsakiris, D A; Fontana, P

    2017-07-01

    Measuring factor VIII (FVIII) activity can be challenging when it has been modified, such as when FVIII is pegylated to increase its circulating half-life. Use of a product-specific reference standard may help avoid this issue. Evaluate the impact of using a product-specific reference standard for measuring the FVIII activity of BAX 855 - a pegylated FVIII - in eight of Switzerland's main laboratories. Factor VIII-deficient plasma, spiked with five different concentrations of BAX 855, plus a control FVIII sample, was sent to the participating laboratories. They measured FVIII activity by using either with a one-stage (OSA) or the chromogenic assay (CA) against their local or a product-specific reference standard. When using a local reference standard, there was an overestimation of BAX 855 activity compared to the target concentrations, both with the OSA and CA. The use of a product-specific reference standard reduced this effect: mean recovery ranged from 127.7% to 213.5% using the OSA with local reference standards, compared to 110% to 183.8% with a product-specific reference standard, and from 146.3% to 182.4% using the CA with local reference standards compared to 72.7% to 103.7% with a product-specific reference standard. In this in vitro study, the type of reference standard had a major impact on the measurement of BAX 855 activity. Evaluation was more accurate and precise when using a product-specific reference standard. © 2017 John Wiley & Sons Ltd.

  11. FIELD CHECK MANUAL FOR LANGUAGE LABORATORIES, A SERIES OF TESTS WHICH A NON-TECHNICAL PERSON CAN CONDUCT TO VERIFY SPECIFICATIONS.

    ERIC Educational Resources Information Center

    GRITTNER, FRANK; PAVLAT, RUSSELL

    IN ORDER TO ASSIST NON-TECHNICAL PEOPLE IN SCHOOLS TO CONDUCT A FIELD CHECK OF LANGUAGE LABORATORY EQUIPMENT BEFORE THEY MAKE FINAL PAYMENTS, THIS MANUAL OFFERS CRITERIA, TESTS, AND METHODS OF SCORING THE QUALITY OF THE EQUIPMENT. CHECKLISTS ARE PROVIDED FOR EVALUATING CONSOLE FUNCTIONS, TAPE RECORDERS, AMPLIFIERS, SOUND QUALITY (INCLUDING…

  12. Regional and field-specific factors affect the composition of Fusarium head blight pathogens in subtropical no-till wheat agroecosystem of Brazil

    USDA-ARS?s Scientific Manuscript database

    A multiyear survey of >200 wheat fields in Paraná (PR) and Rio Grande do Sul (RS) states was conducted to assess the extent and distribution of Fusarium graminearum species complex (FGSC) diversity in the southern Brazilian wheat agroecosystem. Five species and three trichothecene genotypes were fou...

  13. A fourth scale sensitive to the magnetic field; intermolecular frequency symmetry in a specific interaction between protein and low-molecular compound.

    PubMed

    Numao, Naganori; Fukui, Tetsuya; Fukazawa, Yoshiyuki

    2010-12-01

    We found a new method that a specific interaction between prion, i.e., high-molecular compound, and Cp-60, i.e., low-molecular one, could be successfully elucidated with intermolecular frequency symmetry (IFS). To accomplish this, the former sequence is analyzed with a sequence Fourier analysis used average nuclear (N) resonant frequency scale as a fourth one, and the latter structure with a ¹³C-NMR software. Further, such the symmetry could be observed in a specific interaction between a segment of human immunodeficiency virus (HIV)gag and PA-457 or between 1918 neuraminidase and peramivir. Therefore, the IFS rule seems to be evolutionarily conserved as a necessary condition even in a specific protein-organic compound interaction.

  14. Host specificity and genealogy of the louse Polyplax serrata on field mice, Apodemus species: a case of parasite duplication or colonisation?

    PubMed

    Stefka, Jan; Hypsa, Václav

    2008-05-01

    The genealogy, population structure and population dynamics of the sucking louse Polyplax serrata were analysed across four host species of the genus Apodemus. An analysis of 126 sequences of cytochrome c oxidase subunit I using phylogenetic approaches and haplotype networking revealed a clear structure of European samples, forming three distinct and genetically distant clades with different host specificities. Although a clear connection was detected between the host and parasite genealogies/phylogenies, a uniform pattern of co-speciation was not found. For example, a dramatic shift in the degree of host specificity was demonstrated for two related louse lineages living in sympatry and sharing one of their host species. While one of the louse lineages frequently parasitised two different host taxa (Apodemus sylvaticus and Apodemus flavicollis), the other louse lineage was strictly specific to A. flavicollis. The estimate of divergence time between the two louse lineages indicates that they may have arisen due to parasite duplication on A. flavicollis.

  15. Genotype-specific responses of Bromus erectus to elevated CO{sub 2} at different levels of biodiversity and endophyte infection - a field experiment

    SciTech Connect

    Steinger, T.; Groppe, K.; Schmid, B. |

    1995-06-01

    In 1994 we initiated a long-term field experiment in a calcareous grassland to study the effects of elevated CO{sub 2} on individuals, populations, and communities. Clonal replicates of 54 genotypes of the dominant grass Bromus erectus were grown in communities planted at three levels of biodiversity (5-, 12-, 31-species plots) and exposed to ambient and elevated CO{sub 2}. The same genotypes were also individually grown in tubes within the field plots. Some genotypes were infected by the endophytic fungus Epichloee typhina. Elevated CO{sub 2} had no significant effects on plant growth, however, there was large variation among genotypes in all measured characters. A significant CO{sub 2}-by-genotype interaction was found for leaf length in the competition-free tubes. Infection by the endophyte led to the abortion of all inflorescences but increased vegetative growth, especially under competitive conditions.

  16. Dynamics of the large-scale open solar magnetic field and its specific features in the zone of the main active longitudes in 2006-2012

    NASA Astrophysics Data System (ADS)

    Ivanov, K. G.; Kharshiladze, A. F.

    2013-11-01

    The dynamics of the absolute global values (Φ) of the large-scale open solar magnetic field (LOSMF) fluxes at an interval of one solar rotation in 2006-2012 has been studied based on the Wilcox Solar Observatory data and using the ISOPAK original package for modeling the solar magnetic field. The reference points and the duration of the final quasi-biennial interval in cycle 23 (January 2006-May 2007; 17 months) and the phases of the cycle 24 minimum (May 2007-November 2009; 30 months), growth (November 2009-May 2012; 30 months), and the beginning of the maximum (May 2012-January 2013) have been determined. It has been indicated that the absolute values (Φ) decreased sharply at the beginning of the minimum, growth, and the maximum phases to ˜(2, 1.25, 0.75) × 1022 Mx, respectively. During the entire minimum phase, LOSMF corotated super-quasi-rigidly westward in the direction of solar rotation; at the beginning of the growth phase, this field started corotating mostly eastward. The LOSMF polarity reversal in the current cycle 24 started in May-June 2012 (CR 2123-2124), when fields of southern polarity rushed from the Sun's southern hemisphere toward the north. The statement that the solar cycle is a continuous series of quasi-biennial LOSMF intervals is confirmed. In particular, the minimum and growth phases are characterized by opposite LOSMF rotation directions, i.e., super-quasi-rigid corotation (twisting) and detwisting, with identical duration at least in cycle 24.

  17. Analysis of field-angle dependent specific heat in unconventional superconductors: A comparison between Doppler-shift method and Kramer-Pesch approximation

    NASA Astrophysics Data System (ADS)

    Hayashi, Nobuhiko; Nagai, Yuki; Higashi, Yoichi

    2010-12-01

    We theoretically discuss the magnetic-field-angle dependence of the zero-energy density of states (ZEDOS) in superconductors. Point-node and line-node superconducting gaps on spherical and cylindrical Fermi surfaces are considered. The Doppler-shift (DS) method and the Kramer-Pesch approximation (KPA) are used to calculate the ZEDOS. Numerical results show that consequences of the DS method are corrected by the KPA.

  18. RESEARCH PROGRAM FOR BRACE - PROVIDING NO AND SPECIFIC NO2 MEASUREMENTS FOR THE BRACE DATABASE DURING THE MAY '02 FIELD STUDY

    EPA Science Inventory

    Three scientists from the EPA, RTP facility in Research Triangle Park, N.C. worked with the State of Florida and BRACE scientists to provide accurate and precise NO and specific NO2 measurements at two monitoring sites, the rural Sydney site and the near-bay, suburban Gandy sit...

  19. RESEARCH PROGRAM FOR BRACE - PROVIDING NO AND SPECIFIC NO2 MEASUREMENTS FOR THE BRACE DATABASE DURING THE MAY '02 FIELD STUDY

    EPA Science Inventory

    Three scientists from the EPA, RTP facility in Research Triangle Park, N.C. worked with the State of Florida and BRACE scientists to provide accurate and precise NO and specific NO2 measurements at two monitoring sites, the rural Sydney site and the near-bay, suburban Gandy sit...

  20. Ceratapion basicorne (Illiger) (Coleoptera: Curculionidae): laboratory and open field trials to assess its specificity as biocontrol agent of Centaurea solstitialis (Asteraceae: Cardueae)

    USDA-ARS?s Scientific Manuscript database

    Prospective biological control agents generally must be demonstrated to not pose risks to non-target plants. Laboratory experiments evaluating host plant specificity are the most common method of evaluating such risk; however, they are constrained by limitations of space and number of replicates, gi...

  1. Field assessment of host plant specificity and potential effectiveness of a prospective biological control agent, Aceria salsolae, of Russian thistle, Salsola tragus

    USDA-ARS?s Scientific Manuscript database

    The eriophyid mite, Aceria salsolae attacks several species of invasive alien tumbleweeds, including Salsola tragus, S. collina, S. paulsenii and S. australis, in North America. Previous laboratory experiments to determine host specificity of the mite indicated that it could sometimes persist and m...

  2. External control of the Drosophila melanogaster egg to imago development period by specific combinations of 3D low-frequency electric and magnetic fields.

    PubMed

    Makarov, Vladimir I; Khmelinskii, Igor

    2016-01-01

    We report that the duration of the egg-to-imago development period of the Drosophila melanogaster, and the imago longevity, are both controllable by combinations of external 3-dimensional (3D) low-frequency electric and magnetic fields (LFEMFs). Both these periods may be reduced or increased by applying an appropriate configuration of external 3D LFEMFs. We report that the longevity of D. melanogaster imagoes correlates with the duration of the egg-to-imago development period of the respective eggs. We infer that metabolic processes in both eggs and imago are either accelerated (resulting in reduced time periods) or slowed down (resulting in increased time periods). We propose that external 3D LFEMFs induce electric currents in live systems as well as mechanical vibrations on sub-cell, whole-cell and cell-group levels. These external fields induce media polarization due to ionic motion and orientation of electric dipoles that could moderate the observed effects. We found that the longevity of D. melanogaster imagoes is affected by action of 3D LFEMFs on the respective eggs in the embryonic development period (EDP). We interpret this effect as resulting from changes in the regulation mechanism of metabolic processes in D. melanogaster eggs, inherited by the resulting imagoes. We also tested separate effects of either 3D electric or 3D magnetic fields, which were significantly weaker.

  3. Liver: segment-specific analysis of B1 field homogeneity at 3.0-T MR imaging with single-source versus dual-source parallel radiofrequency excitation.

    PubMed

    Pazahr, Shila; Fischer, Michael Alexander; Chuck, Natalie; Luechinger, Roger; Schick, Fritz; Nanz, Daniel; Boss, Andreas

    2012-11-01

    To measure B1 field distribution in different liver segments with and without dual transmission and to quantify the contrast-to-noise ratio (CNR) between normal liver tissue and segmental venous vessels on standard clinical 3.0-T liver magnetic resonance (MR) images. This prospective study was approved by the local ethics committee. All subjects gave written informed consent. Six patients with liver lesions and nine healthy volunteers were included. Average hepatic B1 field values in all Couinaud liver segments were assessed by using actual flip-angle imaging (first and second repetition times msec/echo time msec: 72, 192/2.2; transmission angle: 60°) for both single and dual transmission in a 3.0-T MR imaging unit that allowed both transmission modes. Additionally, two-dimensional T1-weighted gradient-echo (repetition time msec/echo time msec, 180/2.3; transmission angle, 55°) and T2-weighted single-shot fast spin-echo images (1501/80) were acquired. Average CNR between liver parenchyma and segmental veins were measured in each segment. Two-sided paired Student t tests were used for statistical evaluation. Two blinded radiologists independently identified lesions in images from acquisitions in both transmission modes. Mean flip angles achieved with conventional single transmission were 44%-53% of the nominal value in segments II-IV and 67% and 63% of the nominal value in segments VI and VII, respectively, and were less than 77% in all segments. Mean actual flip angles measured for dual transmission were between 82% and 100% of the nominal value in all segments. T1-weighted single-transmission images exhibited areas of low B1 field strength with reduced image contrast. T2-weighted single-transmission images displayed significantly reduced signal intensity but nearly unchanged contrast weighting in these areas. On T1-weighted dual-transmission images, the two readers detected 22 and 14 additional lesions that they did not identify on the single-transmission images

  4. Critical fields and fluctuations determined from specific heat and magnetoresistance in the same nanogram SmFeAs(O,F) single crystal

    NASA Astrophysics Data System (ADS)

    Galeski, S.; Moll, P. W. J.; Zhigadlo, N.; Mattenberger, K.; Batlogg, B.

    2017-09-01

    Through a direct comparison of specific heat and magnetoresistance, we critically asses the nature of superconducting fluctuations in the same nanogram crystal of SmFeAs(O,F). We show that although the superconducting fluctuation contribution to conductivity scales well within the two-dimensional lowest Landau level (2D-LLL) scheme, its predictions contrast with the inherently 3D nature of SmFeAs(O,F) in the vicinity of Tc. Furthermore, the transition seen in specific heat cannot be satisfactory described either by the LLL or the X Y scaling. Additionally we have validated, through comparing Hc 2 values obtained from the entropy conservation construction (Hc 2 //a b=-19.5 T /K and Hc 2 //c=-2.9 T /K ) , the analysis of fluctuation contribution to conductivity as a reasonable method for estimating the H c 2 slope.

  5. A Rapid Field-Deployable Reverse Transcription-Insulated Isothermal Polymerase Chain Reaction Assay for Sensitive and Specific Detection of Bluetongue Virus.

    PubMed

    Ambagala, A; Pahari, S; Fisher, M; Lee, P-Y A; Pasick, J; Ostlund, E N; Johnson, D J; Lung, O

    2017-04-01

    Bluetongue is a non-contagious, haemorrhagic, Culicoides-borne disease of ruminants. The causative agent, bluetongue virus (BTV), is a member of the Orbivirus genus of the Reoviridae family. So far, 26 BTV serotypes have been identified worldwide. The global distribution of bluetongue has been expanding, and rapid detection of BTV, preferably in the field, is critical for timely implementation of animal movement restrictions and vector control measures. To date, many laboratory-based, molecular assays for detection of BTV have been developed. These methods require the samples to be shipped to a central laboratory with sophisticated instruments and highly skilled technicians to perform the assays, conduct analyses and interpret the results. Here, we report the development and evaluation of a rapid, portable, user-friendly, pan-BTV reverse transcription-insulated isothermal polymerase chain reaction (RT-iiPCR) assay that can potentially be used in low-resource field conditions. The total length of the assay was <60 min, and at the end of the assay, the results were automatically displayed as '+' or '-' without the need for data interpretation. The RT-iiPCR assay detected 36 BTV isolates and two in vitro transcribed RNA samples representing all 26 BTV serotypes. The assay did not cross-react with other animal viruses tested, including two closely related orbiviruses. The analytical sensitivity of the assay was as low as nine copies of in vitro transcribed double-stranded BTV RNA. Analysis of BTV-infected whole blood samples showed that the BTV RT-iiPCR assay was as sensitive as real-time RT-PCR. The assay can potentially be used for rapid screening of animals for BTV in routine diagnostics and for monitoring bluetongue outbreaks both in ruminants and in Culicoides vectors in the field and in the laboratory.

  6. Genus-specific kinetoplast-DNA PCR and parasite culture for the diagnosis of localised cutaneous leishmaniasis: applications for clinical trials under field conditions in Brazil.

    PubMed

    Ampuero, Julia; Rios, Alexandre Pereira; Carranza-Tamayo, César Omar; Romero, Gustavo Adolfo Sierra

    2009-11-01

    The positivities of two methods for the diagnosis of localised cutaneous leishmaniasis (CL) were estimated in 280 patients enrolled in a clinical trial. The trial was conducted in an endemic area of Leishmania (Viannia) braziliensis and trial participants were patients with skin ulcers and positive leishmanin skin tests. Patients underwent aspirative skin punctures of the ulcerated lesions and lymph nodes for in vitro cultures, which were processed under field conditions at the local health centre. Skin lesion biopsies were tested at a reference laboratory using kinetoplastid DNA (kDNA)-PCR to detect DNA. The median time required to obtain a positive culture from the skin samples was seven days and the contamination rate of the samples was 1.8%. The positivities of the cultures from skin lesions, kDNA-PCR and the combination of the two methods were 78.2% (95% CI: 73-82.6%), 89.3% (95% CI: 85.1-92.4%) and 97.1% (95% CI: 94.5-98.5%). We conclude that parasite culture is a feasible method for the detection of Leishmania in field conditions and that the combination of culture and PCR has a potential role for the diagnosis of CL in candidates for clinical trials.

  7. Simple, Sensitive, and Specific Detection of Human Immunodeficiency Virus Type 1 Subtype B DNA in Dried Blood Samples for Diagnosis in Infants in the Field

    PubMed Central

    Beck, Ingrid A.; Drennan, Kathryn D.; Melvin, Ann J.; Mohan, Kathey M.; Herz, Arnd M.; Alarcón, Jorge; Piscoya, Julia; Velázquez, Carlos; Frenkel, Lisa M.

    2001-01-01

    The detection of virus is used to diagnose human immunodeficiency virus type 1 (HIV-1) infection in infants due to the persistence of maternal antibodies for a year or more. An HIV-1 DNA PCR assay with simple specimen collection and processing was developed and evaluated. Whole blood was collected on filter paper that lysed cells and bound the DNA, eliminating specimen centrifugation and extraction procedures. The DNA remained bound to the filter paper during PCR amplification. Assays of copy number standards showed reproducible detection of 5 to 10 copies of HIV-1 in 5 μl of whole blood. The sensitivity of the assay did not decrease after storage of the standards on filter paper for 3 months at room temperature or after incubation at 37 or 45°C for 20 h. The primers used for nested PCR of the HIV-1 pol gene amplified templates from a reference panel of multiple HIV-1 subtypes but did not amplify a subtype A or a subtype C virus from children living in Seattle. The assay had a sensitivity of 98.4% and a specificity of 98.3% for testing of 122 specimens from 35 HIV-1-infected and 16 uninfected children and 43 seronegative adults living in Washington. The assay had a sensitivity of 99% and a specificity of 100% for testing of 102 HIV-1-positive (as determined by enzyme immunoassay) Peruvian women and 6 seropositive and 34 seronegative infants. This assay, with adsorption of whole blood to filter paper and no specimen processing, provides a practical, economical, sensitive, and specific method for the diagnosis of HIV-1 subtype B infection in infants. PMID:11136743

  8. Drilling Specifications: Well Installations in the 300 Area to Support PNNL’s Integrated Field-Scale Subsurface Research Challenge (IFC) Project

    SciTech Connect

    Bjornstad, Bruce N.; Vermeul, Vince R.

    2008-01-21

    Part of the 300 Area Integrated Field-Scale Subsurface Research Challenge (IFC) will be installation of a network of high density borings and wells to monitor migration of fluids and contaminants (uranium), both in groundwater and vadose zone, away from an surface infiltration plot (Figure A-1). The infiltration plot will be located over an area of suspected contamination at the former 300 Area South Process Pond (SPP). The SPP is located in the southeastern portion of the Hanford Site, within the 300-FF-5 Operable Unit. Pacific Northwest National Laboratory (PNNL) with the support of FH shall stake the well locations prior to the start of drilling. Final locations will be based on accessibility and will avoid any surface or underground structures or hazards as well as surface contamination.

  9. Cheap but accurate calculation of chemical reaction rate constants from ab initio data, via system-specific, black-box force fields

    NASA Astrophysics Data System (ADS)

    Steffen, Julien; Hartke, Bernd

    2017-10-01

    Building on the recently published quantum-mechanically derived force field (QMDFF) and its empirical valence bond extension, EVB-QMDFF, it is now possible to generate a reliable potential energy surface for any given elementary reaction step in an essentially black box manner. This requires a limited and pre-defined set of reference data near the reaction path and generates an accurate approximation of the reference potential energy surface, on and off the reaction path. This intermediate representation can be used to generate reaction rate data, with far better accuracy and reliability than with traditional approaches based on transition state theory (TST) or variational extensions thereof (VTST), even if those include sophisticated tunneling corrections. However, the additional expense at the reference level remains very modest. We demonstrate all this for three arbitrarily chosen example reactions.

  10. Cheap but accurate calculation of chemical reaction rate constants from ab initio data, via system-specific, black-box force fields.

    PubMed

    Steffen, Julien; Hartke, Bernd

    2017-10-28

    Building on the recently published quantum-mechanically derived force field (QMDFF) and its empirical valence bond extension, EVB-QMDFF, it is now possible to generate a reliable potential energy surface for any given elementary reaction step in an essentially black box manner. This requires a limited and pre-defined set of reference data near the reaction path and generates an accurate approximation of the reference potential energy surface, on and off the reaction path. This intermediate representation can be used to generate reaction rate data, with far better accuracy and reliability than with traditional approaches based on transition state theory (TST) or variational extensions thereof (VTST), even if those include sophisticated tunneling corrections. However, the additional expense at the reference level remains very modest. We demonstrate all this for three arbitrarily chosen example reactions.

  11. Serotypic differentiation of rotaviruses in field samples from diarrheic pigs by using nucleic acid probes specific for porcine VP4 and human and porcine VP7 genes.

    PubMed Central

    Rosen, B I; Parwani, A V; Lopez, S; Flores, J; Saif, L J

    1994-01-01

    Of 216 fecal and intestinal samples collected from nursing or weaned diarrheic pigs in the United States and Canada, 57 were identified as group A rotavirus positive by RNA electrophoresis and silver staining. Fifty-seven and 52 rotavirus-positive samples were analyzed by hybridization with Gottfried and OSU PCR-derived gene 9 and 4 probes, respectively. Only 17 samples were identified with either homologous VP4 (P)- or VP7 (G)-coding genes or both. One rotavirus identified as G4 and P7 was similar to the previously characterized interserotype rotavirus, SB-1A. Additional hybridization analyses were performed with PCR-derived probes prepared from gene 9 cDNA of the human rotaviruses Wa (G1), DS-1 (G2), and P (G3) and of the porcine rotavirus YM (G11). Eleven of 52 samples collected and analyzed from swine in Ohio, California, and Nebraska were identified as G11. No samples with G1-, G2-, or G3-type specificities were detected among the 25 of 57 rotavirus-positive samples analyzed with human rotavirus-derived probes. Further investigations with a PCR-derived gene 4 probe prepared from porcine rotavirus YM revealed hybridization specificities similar to those of the OSU gene 4 probe. Images PMID:8150940

  12. Novel genus-specific broad range primers for the detection of furoviruses, hordeiviruses and rymoviruses and their application in field surveys in South-East Australia.

    PubMed

    Zheng, Linda; Tang, Joe; Clover, Gerard R G; Spackman, Merrin E; Freeman, Angela J; Rodoni, Brendan C

    2015-03-01

    A number of viruses from the genera Furovirus, Hordeivirus and Rymovirus are known to infect and damage the four major temperate cereal crops, wheat, barley, sorghum and oats. Currently, there is no active testing in Australia for any of these viruses, which pose a significant biosecurity threat to the phytosanitary status of Australia's grains industry. To address this, broad spectrum PCR assays were developed to target virus species within the genera Furovirus, Hordeivirus and Rymovirus. Five sets of novel genus-specific primers were designed and tested in reverse-transcription polymerase chain reaction assays against a range of virus isolates in plant virus diagnostic laboratories in both Australia and New Zealand. Three of these assays were then chosen to screen samples in a three-year survey of cereal crops in western Victoria, Australia. Of the 8900 cereal plants screened in the survey, all were tested free of furoviruses, hordeiviruses and rymoviruses. To date, there were no published genus-specific primers available for the detection of furoviruses, hordeiviruses and rymoviruses. This study shows for the first time a broad-spectrum molecular test being used in a survey for exotic grain viruses in Australia. Results from this survey provide important evidence of the use of this method to demonstrate the absence of these viruses in Victoria, Australia. The primer pairs reported here are expected to detect a wide range of virus species within the three genera.

  13. The specific role of fungal community structure on soil aggregation and carbon sequestration: results from long-term field study in a paddy soil

    NASA Astrophysics Data System (ADS)

    Murugan, Rajasekaran; Kumar, Sanjay

    2015-04-01

    Soil aggregate stability is a crucial soil property that affects soil biota, biogeochemical processes and C sequestration. The relationship between soil aggregate stability and soil C cycling is well known but the influence of specific fungal community structure on this relationship is largely unknown in paddy soils. The aim of the present study was to evaluate the long-term fertilisation (mineral fertiliser-MIN; farmyard manure-FYM; groundnut oil cake-GOC) effects on soil fungal community shifts associated with soil aggregates under rice-monoculture (RRR) and rice-legume-rice (RLR) systems. Fungal and bacterial communities were characterized using phospholipid fatty acids, and glucosamine and muramic acid were used as biomarkers for fungal and bacterial residues, respectively. Microbial biomass C and N, fungal biomass and residues were significantly higher in the organic fertiliser treatments than in the MIN treatment, for all aggregate sizes under both crop rotation systems. In general, fungal/bacterial biomass ratio and fungal residue C/bacterial residue C ratio were significantly higher in macroaggregate fractions (> 2000 and 250-2000 μm) than in microaggregate fractions (53-250 and <53 μm). In both crop rotation systems, the long-term application of FYM and GOC led to increased accumulation of saprotrophic fungi (SF) in aggregate fractions > 2000 μm. In contrast, we found that arbuscular mycorrhizal fungi (AMF) was surprisingly higher in aggregate fractions > 2000 μm than in aggregate fraction 250-2000 μm under MIN treatment. The RLR system showed significantly higher AMF biomass and fungal residue C/ bacterial residue C ratio in both macroaggregate fractions compared to the RRR system. The strong relationships between SF, AMF and water stable aggregates shows the specific contribution of fungi community on soil aggregate stability. Our results highlight the fact that changes within fungal community structure play an important role in shaping the soil

  14. Resistance and mutations of non-specificity in the field of anxiety-depressive disorders in Canadian medical journals, 1950-1990.

    PubMed

    Collin, Johanne; Otero, Marcelo

    2015-04-01

    Pharmaceuticalisation is a complex phenomenon, co-constitutive of what scholars identify as a pharmaceutical regime, comprised of networks of actors, institutions and artefacts as well as cognitive structures that underlie the production, promotion and use of medications. The aim of this paper is to explore the linkages between different components of this pharmaceutical regime through the analysis of psychotropic drug advertising in Canadian medical journals between 1950 and 1990. Advertisements stand at the nexus of macro-level processes related to the development, regulation and marketing of new drug treatments and of micro-level processes related to the use of these drug treatments, both by clinicians and lay persons. We thus examine advertisements from the angle of the mental and classificatory universes to which doctors were exposed through direct-to-prescriber advertisement strategies implemented during this period. Furthermore, we explore to what extent the rationale behind advertisements was permeated by both scientific/professional and popular narratives of mind-body connections. This paper demonstrates that, although this period was marked by paradigm shifts in the classification of mental diseases, the development of modern psychopharmacology, and the questioning of the scientific legitimacy of psychiatry, advertisements unveil a remarkable continuity: that of the mass management of anxiety-depressive disorders by primary care physicians through psychotropic drugs. Also, despite the effective resistance to specificity as shown by the constant redefinitions of diagnostic categories and therapeutic indications, our analysis suggests that the language of specificity used in the promotion of new drugs and in the various narratives of mind-body connection may have been appealing to general practitioners. Finally, our study of the classes of psychoactive medications that have been in use for over half a century reveals a complex, non-linear dynamic of

  15. Accuracy and reliability of GPS devices for measurement of sports-specific movement patterns related to cricket, tennis, and field-based team sports.

    PubMed

    Vickery, William M; Dascombe, Ben J; Baker, John D; Higham, Dean G; Spratford, Wayne A; Duffield, Rob

    2014-06-01

    The aim of this study was to determine the accuracy and reliability of 5, 10, and 15 Hz global positioning system (GPS) devices. Two male subjects (mean ± SD; age, 25.5 ± 0.7 years; height, 1.75 ± 0.01 m; body mass, 74 ± 5.7 kg) completed 10 repetitions of drills replicating movements typical of tennis, cricket, and field-based (football) sports. All movements were completed wearing two 5 and 10 Hz MinimaxX and 2 GPS-Sports 15 Hz GPS devices in a specially designed harness. Criterion movement data for distance and speed were provided from a 22-camera VICON system sampling at 100 Hz. Accuracy was determined using 1-way analysis of variance with Tukey's post hoc tests. Interunit reliability was determined using intraclass correlation (ICC), and typical error was estimated as coefficient of variation (CV). Overall, for the majority of distance and speed measures, as measured using the 5, 10, and 15 Hz GPS devices, were not significantly different (p > 0.05) to the VICON data. Additionally, no improvements in the accuracy or reliability of GPS devices were observed with an increase in the sampling rate. However, the CV for the 5 and 15 Hz devices for distance and speed measures ranged between 3 and 33%, with increasing variability evident in higher speed zones. The majority of ICC measures possessed a low level of interunit reliability (r = -0.35 to 0.39). Based on these results, practitioners of these devices should be aware that measurements of distance and speed may be consistently underestimated, regardless of the movements performed.

  16. Area- and band-specific representations of hand movements by local field potentials in caudal cingulate motor area and supplementary motor area of monkeys

    PubMed Central

    Yokoyama, Osamu; Nakayama, Yoshihisa

    2016-01-01

    The caudal cingulate motor area (CMAc) and the supplementary motor area (SMA) play important roles in movement execution. The present study examined the neural mechanisms underlying these roles by investigating local field potentials (LFPs) from these areas while monkeys pressed buttons with either their left or right hand. During hand movement, power increases in the high-gamma (80–120 Hz) and theta (3–8 Hz) bands and a power decrease in the beta (12–30 Hz) band were observed in both the CMAc and SMA. High-gamma and beta activity in the SMA predominantly represented contralateral hand movements, whereas activity in the CMAc preferentially represented movement of either hand. Theta activity in both brain regions most frequently reflected movement of either hand, but a contralateral hand bias was more evident in the SMA than in the CMAc. An analysis of the relationships of the laterality representations between the high-gamma and theta bands at each recording site revealed that, irrespective of the hand preference for the theta band, the high-gamma band in the SMA preferentially represented contralateral hand movement, whereas the high-gamma band in the CMAc represented movement of either hand. These findings suggest that the input-output relationships for ipsilateral and contralateral hand movements in the CMAc and SMA differ in terms of their functionality. The CMAc may transform the input signals representing general aspects of movement into commands to perform movements with either hand, whereas the SMA may transform the input signals into commands to perform movement with the contralateral hand. PMID:26792884

  17. Area- and band-specific representations of hand movements by local field potentials in caudal cingulate motor area and supplementary motor area of monkeys.

    PubMed

    Yokoyama, Osamu; Nakayama, Yoshihisa; Hoshi, Eiji

    2016-03-01

    The caudal cingulate motor area (CMAc) and the supplementary motor area (SMA) play important roles in movement execution. The present study examined the neural mechanisms underlying these roles by investigating local field potentials (LFPs) from these areas while monkeys pressed buttons with either their left or right hand. During hand movement, power increases in the high-gamma (80-120 Hz) and theta (3-8 Hz) bands and a power decrease in the beta (12-30 Hz) band were observed in both the CMAc and SMA. High-gamma and beta activity in the SMA predominantly represented contralateral hand movements, whereas activity in the CMAc preferentially represented movement of either hand. Theta activity in both brain regions most frequently reflected movement of either hand, but a contralateral hand bias was more evident in the SMA than in the CMAc. An analysis of the relationships of the laterality representations between the high-gamma and theta bands at each recording site revealed that, irrespective of the hand preference for the theta band, the high-gamma band in the SMA preferentially represented contralateral hand movement, whereas the high-gamma band in the CMAc represented movement of either hand. These findings suggest that the input-output relationships for ipsilateral and contralateral hand movements in the CMAc and SMA differ in terms of their functionality. The CMAc may transform the input signals representing general aspects of movement into commands to perform movements with either hand, whereas the SMA may transform the input signals into commands to perform movement with the contralateral hand. Copyright © 2016 the American Physiological Society.

  18. Evaluation of a rabbit model for osteomyelitis by high field, high resolution imaging using the chemical-shift-specific-slice-selection technique.

    PubMed

    Volk, A; Crémieux, A C; Belmatoug, N; Vallois, J M; Pocidalo, J J; Carbon, C

    1994-01-01

    The rabbit model of osteomyelitis introduced by C.W. Norden, based on injection of an infecting solution (Staphylococcus aureus, sodium morrhuate) into the tibia, was studied at 4.7 Tesla with a time-efficient chemical shift selective imaging technique, Chemical Shift Specific Slice Selection (C4S). The evolution of the disease over several weeks was followed on water-selective, fat-selective, and sum images obtained simultaneously with this imaging sequence. Experiments were performed either on different groups of rabbits at different times after infection with subsequent sacrifice of the animal and microbiological analysis of the infected tibia or on the same group of animals imaged several times after infection. Associated analysis of the water and fat selective images revealed marrow modifications very early (Day 5 after inoculation) demonstrating the high sensitivity of the employed imaging technique. Later on, bone modifications were best identified on the sum images. Additional experiments performed on animals injected with a noninfecting solution containing only sodium morrhuate showed however that the sclerosing agent alone can yield images similar to those produced by infection at early stages after inoculation. Therefore, the Norden model would not be suitable for monitoring quantitatively outcome of therapy by magnetic resonance imaging. It is however well adapted for the evaluation and optimization of MRI techniques or protocols intended to detect early changes of bone marrow produced by septic or aseptic infarct.

  19. Beyond Field Education: Leadership of Field Directors

    ERIC Educational Resources Information Center

    Wertheimer, Mindy R.; Sodhi, Mimi

    2014-01-01

    This article presents a conceptual model of the field director's role outside of field education, specifically in the following 3 areas of leadership: (1) curricular, (2) programmatic, and (3) institutional. A survey was conducted to explore the field director's input targeted in these areas beyond prescribed field education tasks. The…

  20. LiCaAlF6 scintillators in neutron and gamma radiation fields

    NASA Astrophysics Data System (ADS)

    Viererbl, L.; Klupák, V.; Vinš, M.; Koleška, M.; Šoltés, J.; Yoshikawa, A.; Nikl, M.

    2016-09-01

    Intentionally doped LiCaAlF6 (LiCAF) single crystals are prospective scintillators, especially for thermal neutron detection through the 6Li(n,t)4He nuclear reaction. Four different LiCAF scintillator samples were tested in various neutron and gamma fields. Two of the tested samples were LiCAF:Eu and LiCAF:Eu,Na single crystals, and another two samples were made of LiCAF:Eu micro crystals dispersed in transparent rubber, with different rubber dimensions. All LiCAF samples contain lithium enriched to6Li. A plutonium-beryllium source was used as a neutron source. The neutron spectrum was modified by moderator and filter to get different ratios between thermal, epithermal and fast neutron fluence rates. The MCNP code was used for calculations of the fluence rates for different configurations. Radionuclides 137Cs and 60Co were applied as gamma radiation sources. The light signal from the scintillator was evaluated with a photomultiplier and a multichannel analyzer. The purpose of this work was to study the characteristics of LiCAF scintillators, especially the ability to discriminate signals from neutron and gamma radiation, which is the basic scintillator condition for neutron detection in mixed neutron-gamma radiation fields. Generally, the discrimination can be done by the pulse height and/or the pulse shape of the evaluated signals. Both methods can be used for a LiCAF scintillator. However, only the pulse height discrimination method is discussed in this paper. The possibility of fast neutron detection with LiCAF scintillators was also tested.

  1. Delayed Neutron & Gamma Measurements of Special Nuclear Materials and MCNP6 Simulations

    SciTech Connect

    Sellers, Madison; Goorley, John T.; Corcoran, E. C.; Kelly, D. G.

    2014-01-21

    Measurements of DG emissions from 0.8 – 1.6 MeV were compared to MCNP6 simulations. Several discrepancies were resolved with use of ENDFVII.1 decay data. Furthermore, MCNP6 was executable with delayed bin fix resolved several line intensity discrepancies.

  2. Investigating the anisotropic scintillation response in anthracene through neutron, gamma-ray, and muon measurements

    SciTech Connect

    Schuster, Patricia; Brubaker, Erik

    2016-05-05

    Our paper reports a series of measurements that characterize the directional dependence of the scintillation response of crystalline anthracene to incident DT neutrons, DD neutrons, 137Cs gamma rays, and, for the first time, cosmic ray muons. Moreover, the neutron measurements give the amplitude and pulse shape dependence on the proton recoil direction over one hemisphere of the crystal, confirming and extending previous results in the literature. In similar measurements using incident gamma rays, no directional effect is evident, and any anisotropy with respect to the electron recoil direction is constrained to have a magnitude of less than a tenth of that present in the proton recoil events. Cosmic muons are measured at two directions, and no anisotropy is observed. Our set of observations indicates that high dE/dx is necessary for an anisotropy to be present for a given type of scintillation event, which in turn could be used to discriminate among different hypotheses for the underlying causes of the anisotropy, which are not well understood.

  3. Investigating the anisotropic scintillation response in anthracene through neutron, gamma-ray, and muon measurements

    DOE PAGES

    Schuster, Patricia; Brubaker, Erik

    2016-05-05

    Our paper reports a series of measurements that characterize the directional dependence of the scintillation response of crystalline anthracene to incident DT neutrons, DD neutrons, 137Cs gamma rays, and, for the first time, cosmic ray muons. Moreover, the neutron measurements give the amplitude and pulse shape dependence on the proton recoil direction over one hemisphere of the crystal, confirming and extending previous results in the literature. In similar measurements using incident gamma rays, no directional effect is evident, and any anisotropy with respect to the electron recoil direction is constrained to have a magnitude of less than a tenth ofmore » that present in the proton recoil events. Cosmic muons are measured at two directions, and no anisotropy is observed. Our set of observations indicates that high dE/dx is necessary for an anisotropy to be present for a given type of scintillation event, which in turn could be used to discriminate among different hypotheses for the underlying causes of the anisotropy, which are not well understood.« less

  4. A dual neutron/gamma source for the Fissmat Inspection for Nuclear Detection (FIND) system.

    SciTech Connect

    Doyle, Barney Lee; King, Michael; Rossi, Paolo; McDaniel, Floyd Del; Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak; Raber, Thomas N.

    2008-12-01

    Shielded special nuclear material (SNM) is very difficult to detect and new technologies are needed to clear alarms and verify the presence of SNM. High-energy photons and neutrons can be used to actively interrogate for heavily shielded SNM, such as highly enriched uranium (HEU), since neutrons can penetrate gamma-ray shielding and gamma-rays can penetrate neutron shielding. Both source particles then induce unique detectable signals from fission. In this LDRD, we explored a new type of interrogation source that uses low-energy proton- or deuteron-induced nuclear reactions to generate high fluxes of mono-energetic gammas or neutrons. Accelerator-based experiments, computational studies, and prototype source tests were performed to obtain a better understanding of (1) the flux requirements, (2) fission-induced signals, background, and interferences, and (3) operational performance of the source. The results of this research led to the development and testing of an axial-type gamma tube source and the design/construction of a high power coaxial-type gamma generator based on the {sup 11}B(p,{gamma}){sup 12}C nuclear reaction.

  5. Testing of regolith of celestial bolides with active neutron gamma-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Vostrukhin, Andrey; Mitrofanov, Igor; Golovin, Dmitry; Litvak, Maxim; Sanin, Anton

    2015-04-01

    Current space instruments for studying planet's surface include gamma ray spectrometers that detect natural radioactive isotopes as well as gamma-rays induced in subsurface by galactic cosmic rays. When measuring from celestial body's surface, statistics and amount of detected elements can be dramatically increased with active methods, where soil exposed to artificial flux of particles. One good example is the Russian Dynamic Albedo of Neutron (DAN) instrument onboard Martian Science Laboratory mission (Curiosity rover) developed in 2005-2011. It is the first active neutron spectrometer flown to another planet as part of a landed mission to investigate subsurface water distribution and which has now successfully operated for more than two years on the Martian surface. Presentation describes a number of space instruments for different landers and rovers being developed in Russian Space Research Institute for studying Moon and Mars, as well as method of active neutron and gamma spectrometry overview.

  6. Measurements of soil carbon by neutron-gamma analysis in static and scanning modes

    USDA-ARS?s Scientific Manuscript database

    The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of gamma rays created when neutrons interact with soil elements. The main parts of the INS system are a pulsed neutron generator, NaI(Tl) gamma detecto...

  7. Features of the measurement of fat in meat using the neutron/gamma transmission (NEUGAT) method.

    PubMed

    Bartle, C M

    1995-08-01

    Practical requirements for the non-invasive measurement of the composition by weight of fat in boneless meat are discussed including taking into account the effects of variation in product thickness, and illustrating the importance of the dual beam approach in making measurements for production-line meat boxes. Insensitivity to the fat distribution and product temperature, and the agreement between the theoretical and experimental values of the statistical spread are shown. A comparison is made of measurement using an 241Am-Be and a 252Cf source.

  8. Investigating the anisotropic scintillation response in anthracene through neutron, gamma-ray, and muon measurements

    SciTech Connect

    Schuster, Patricia; Brubaker, Erik

    2016-05-05

    Our paper reports a series of measurements that characterize the directional dependence of the scintillation response of crystalline anthracene to incident DT neutrons, DD neutrons, 137Cs gamma rays, and, for the first time, cosmic ray muons. Moreover, the neutron measurements give the amplitude and pulse shape dependence on the proton recoil direction over one hemisphere of the crystal, confirming and extending previous results in the literature. In similar measurements using incident gamma rays, no directional effect is evident, and any anisotropy with respect to the electron recoil direction is constrained to have a magnitude of less than a tenth of that present in the proton recoil events. Cosmic muons are measured at two directions, and no anisotropy is observed. Our set of observations indicates that high dE/dx is necessary for an anisotropy to be present for a given type of scintillation event, which in turn could be used to discriminate among different hypotheses for the underlying causes of the anisotropy, which are not well understood.

  9. Anisn-Dort Neutron-Gamma Flux Intercomparison Exercise for a Simple Testing Model

    NASA Astrophysics Data System (ADS)

    Boehmer, B.; Konheiser, J.; Borodkin, G.; Brodkin, E.; Egorov, A.; Kozhevnikov, A.; Zaritsky, S.; Manturov, G.; Voloschenko, A.

    2003-06-01

    The ability of transport codes ANISN, DORT, ROZ-6, MCNP and TRAMO, as well as nuclear data libraries BUGLE-96, ABBN-93, VITAMIN-B6 and ENDF/B-6 to deliver consistent gamma and neutron flux results was tested in the calculation of a one-dimensional cylindrical model consisting of a homogeneous core and an outer zone with a single material. Model variants with H2O, Fe, Cr and Ni in the outer zones were investigated. The results are compared with MCNP-ENDF/B-6 results. Discrepancies are discussed. The specified test model is proposed as a computational benchmark for testing calculation codes and data libraries.

  10. Investigating the Anisotropic Scintillation Response in Anthracene through Neutron, Gamma-Ray, and Muon Measurements

    NASA Astrophysics Data System (ADS)

    Schuster, Patricia; Brubaker, Erik

    2016-06-01

    This paper reports a series of measurements that characterize the directional dependence of the scintillation response of crystalline anthracene to incident DT neutrons, DD neutrons, Cs-137 gamma rays, and, for the first time, cosmic ray muons. The neutron measurements give the amplitude and pulse shape dependence on the proton recoil direction over one hemisphere of the crystal, confirming and extending previous results in the literature. In similar measurements using incident gamma rays, no directional effect is evident, and any anisotropy with respect to the electron recoil direction is constrained to have a magnitude of less than a tenth of that present in the proton recoil events. Cosmic muons are measured at two directions, and no anisotropy is observed. This set of observations indicates that high dE/dx is necessary for an anisotropy to be present for a given type of scintillation event, which in turn could be used to discriminate among different hypotheses for the underlying causes of the anisotropy, which are not well understood.

  11. Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes.

    PubMed

    Yakubova, Galina; Kavetskiy, Aleksandr; Prior, Stephen A; Torbert, H Allen

    2017-08-24

    The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of gamma rays created when neutrons interact with soil elements. The main parts of the INS system are a pulsed neutron generator, NaI(Tl) gamma detectors, split electronics to separate gamma spectra due to INS and thermo-neutron capture (TNC) processes, and software for gamma spectra acquisition and data processing. This method has several advantages over other methods in that it is a non-destructive in situ method that measures the average carbon content in large soil volumes, is negligibly impacted by local sharp changes in soil carbon, and can be used in stationary or scanning modes. The result of the INS method is the carbon content from a site with a footprint of ~2.5 - 3 m(2) in the stationary regime, or the average carbon content of the traversed area in the scanning regime. The measurement range of the current INS system is >1.5 carbon weight % (standard deviation ± 0.3 w%) in the upper 10 cm soil layer for a 1 hmeasurement.

  12. Neutron-gamma flux and dose calculations in a Pressurized Water Reactor (PWR)

    NASA Astrophysics Data System (ADS)

    Brovchenko, Mariya; Dechenaux, Benjamin; Burn, Kenneth W.; Console Camprini, Patrizio; Duhamel, Isabelle; Peron, Arthur

    2017-09-01

    The present work deals with Monte Carlo simulations, aiming to determine the neutron and gamma responses outside the vessel and in the basemat of a Pressurized Water Reactor (PWR). The model is based on the Tihange-I Belgian nuclear reactor. With a large set of information and measurements available, this reactor has the advantage to be easily modelled and allows validation based on the experimental measurements. Power distribution calculations were therefore performed with the MCNP code at IRSN and compared to the available in-core measurements. Results showed a good agreement between calculated and measured values over the whole core. In this paper, the methods and hypotheses used for the particle transport simulation from the fission distribution in the core to the detectors outside the vessel of the reactor are also summarized. The results of the simulations are presented including the neutron and gamma doses and flux energy spectra. MCNP6 computational results comparing JEFF3.1 and ENDF-B/VII.1 nuclear data evaluations and sensitivity of the results to some model parameters are presented.

  13. [sup 3]He neutron detector performance in mixed neutron gamma environments

    SciTech Connect

    Johnson, N. H.; Beddingfield, D. H.

    2002-01-01

    A test program of the performance of 3He neutron proportional detectors with varying gas pressures, and their response to lligh level gamma-ray exposure in a mixed neutrodgamma environment, ha$ been performed Our intent was to identie the optimal gas pressure to reduce the gamma-ray sensitivity of these detectors. These detectors were manufxtured using materials to minimize their gamma response. Earlier work focused on 3He fill pressures of four atmospheres and above, whereas the present work focuses on a wider range of pressures. Tests have shown that reducing the .filling pressure will M e r increase the gamma-ray dose range in which the detectors can be operated.

  14. Neutron-gamma discrimination via PSD plastic scintillator and SiPMs

    NASA Astrophysics Data System (ADS)

    Taggart, M. P.; Payne, C.; Sellin, P. J.

    2016-10-01

    The reduction in availability and inevitable increase in cost of traditional neutron detectors based on the 3He neutron capture reaction has resulted in a concerted effort to seek out new techniques and detection media to meet the needs of national nuclear security. Traditionally, the alternative has been provided through pulse shape discrimination (PSD) using liquid scintillators. However, these are not without their own inherent issues, primarily concerning user safety and ongoing maintenance. A potential system devised to separate neutron and gamma ray pulses utilising the PSD technique takes advantage of recent improvements in silicon photomultiplier (SiPM) technology and the development of plastic scintillators exhibiting the PSD phenomena. In this paper we present the current iteration of this ongoing work having achieved a Figure of Merit (FoM) of 1.39 at 1.5 MeVee.

  15. Neutron/gamma pulse shape discrimination (PSD) in plastic scintillators with digital PSD electronics

    NASA Astrophysics Data System (ADS)

    Hutcheson, Anthony L.; Simonson, Duane L.; Christophersen, Marc; Phlips, Bernard F.; Charipar, Nicholas A.; Piqué, Alberto

    2013-05-01

    Pulse shape discrimination (PSD) is a common method to distinguish between pulses produced by gamma rays and neutrons in scintillator detectors. This technique takes advantage of the property of many scintillators that excitations by recoil protons and electrons produce pulses with different characteristic shapes. Unfortunately, many scintillating materials with good PSD properties have other, undesirable properties such as flammability, toxicity, low availability, high cost, and/or limited size. In contrast, plastic scintillator detectors are relatively low-cost, and easily handled and mass-produced. Recent studies have demonstrated efficient PSD in plastic scintillators using a high concentration of fluorescent dyes. To further investigate the PSD properties of such systems, mixed plastic scintillator samples were produced and tested. The addition of up to 30 wt. % diphenyloxazole (DPO) and other chromophores in polyvinyltoluene (PVT) results in efficient detection with commercial detectors. These plastic scintillators are produced in large diameters up to 4 inches by melt blending directly in a container suitable for in-line detector use. This allows recycling and reuse of materials while varying the compositions. This strategy also avoids additional sample handling and polishing steps required when using removable molds. In this presentation, results will be presented for different mixed-plastic compositions and compared with known scintillating materials

  16. Neutron/gamma coupled library generation and gamma transport calculation with KARMA 1.2

    SciTech Connect

    Hong, S. G.; Kim, K. S.; Cho, J. Y.; Lee, K. H.

    2012-07-01

    KAERI has developed a lattice transport calculation code KARMA and its multi-group cross section library generation system. Recently, the multi-group cross section library generation system has included a gamma cross section generation capability and KARMA also has been improved to include a gamma transport calculation module. This paper addresses the multi-group gamma cross section generation capability for the KARMA 1.2 code and the preliminary test results of the KARMA 1.2 gamma transport calculations. The gamma transport calculation with KARMA 1.2 gives the gamma flux, gamma smeared power, and gamma energy deposition distributions. The results of the KARMA gamma calculations were compared with those of HELIOS and they showed that KARMA 1.2 gives reasonable gamma transport calculation results. (authors)

  17. Design and performance of a new high accuracy combined small sample neutron/gamma detector

    SciTech Connect

    Menlove, H.; Davidson, D.; Verplancke, J.; Vermeulen, P.; Wagner, H.G.; Wellum, R.; Brandelise, B.; Mayer, K.

    1993-08-01

    This paper describes the design of an optimized combined neutron and gamma detector installed around a measurement well protruding from the floor of a glove box. The objective of this design was to achieve an overall accuracy for the plutonium element concentration in gram-sized samples of plutonium oxide powder approaching the {approximately}0.1--0.2% accuracies routinely achieved by inspectors` chemical analysis. The efficiency of the clam-shell neutron detector was increased and the flat response zone extended in axial and radial directions. The sample holder introduced from within the glove box was designed to form the upper reflector, while two graphite half-shells fitted around the thin neck of the high-resolution LEGE detector replaced the lower plug. The Institute for Reference Materials and Measurements (IRMM) in Geel prepared special plutonium oxide test samples whose plutonium concentration was determined to better than 0.05%. During a three week initial performance test in July 1992 at ITU Karlsruhe and in long term tests, it was established that the target accuracy can be achieved provided sufficient care is taken to assure the reproducibility of sample bottling and sample positioning. The paper presents and discusses the results of all test measurements.

  18. Improved pulse shape discriminator for fast neutron-gamma ray detection system

    NASA Technical Reports Server (NTRS)

    Lockwood, J. A.; St. Onge, R.

    1969-01-01

    Discriminator in nuclear particle detection system distinguishes nuclear particle type and energy among many different nuclear particles. Discriminator incorporates passive, linear circuit elements so that it will operate over a wide dynamic range.

  19. Time-resolved Neutron-gamma-ray Data Acquisition for in Situ Subsurface Planetary Geochemistry

    NASA Technical Reports Server (NTRS)

    Bodnarik, Julie G.; Burger, Dan Michael; Burger, A.; Evans, L. G.; Parsons, A. M.; Schweitzer, J. S.; Starr R. D.; Stassun, K. G.

    2013-01-01

    The current gamma-ray/neutron instrumentation development effort at NASA Goddard Space Flight Center aims to extend the use of active pulsed neutron interrogation techniques to probe the subsurface elemental composition of planetary bodies in situ. Previous NASA planetary science missions, that used neutron and/or gamma-ray spectroscopy instruments, have relied on neutrons produced from galactic cosmic rays. One of the distinguishing features of this effort is the inclusion of a high intensity 14.1 MeV pulsed neutron generator synchronized with a custom data acquisition system to time each event relative to the pulse. With usually only one opportunity to collect data, it is difficult to set a priori time-gating windows to obtain the best possible results. Acquiring time-tagged, event-by-event data from nuclear induced reactions provides raw data sets containing channel/energy, and event time for each gamma ray or neutron detected. The resulting data set can be plotted as a function of time or energy using optimized analysis windows after the data are acquired. Time windows can now be chosen to produce energy spectra that yield the most statistically significant and accurate elemental composition results that can be derived from the complete data set. The advantages of post-processing gamma-ray time-tagged event-by-event data in experimental tests using our prototype instrument will be demonstrated.

  20. Performance tests on PNL`s transportable neutron/gamma waste assay system

    SciTech Connect

    Haggard, D.L.; Davidson, D.; Lemons, C.J.

    1995-12-31

    Battelle Pacific Northwest Laboratory, in conjunction with Canberra Industries, has implemented a 55-gallon drum waste assay system. The single system unit consists of a combined segmented gamma assay system and a neutron assay system. The unit is designed to function either in the laboratory or in a mobile trailer. The system is on wheels and can be moved through standard double doors. The gamma system uses an HPGe detector with a Se-75 source for transmission corrections. The neutron detector uses 40 He-3 detectors connected to a JSR-12 neutron coincidence counter. The system`s software is unique and is interactive with the user; it features a menu driven operator screen from which all functions regarding operations and calibrations can be selected. Single or combined assays with various setups, including containers smaller than 55 gallons, may be performed. The software and analysis is designed for unknown waste contents, but allows input of waste stream information prior to assay. The system was originally designed for safeguards` MC&A requirements and has enough sensitivity to determine whether a drum is TRU or LLW in one assay pass. Typical counting times are approximately 1800 seconds for a dual pass. Preliminary testing of the system with the available Pu standards has shown the system will perform to the required levels stated in the Data Quality Objectives of the WIPP Performance Demonstration program. An overall study of the system is underway to determine the lower limit of detection (LLD) for different isotopes, to best utilize the combined assay results, and to apply the appropriate data corrections for more complete answers, such as corrections for the end effects. Results from these developments will be presented at the conference.

  1. Simulation of the Mg(Ar) ionization chamber currents by different Monte Carlo codes in benchmark gamma fields

    NASA Astrophysics Data System (ADS)

    Lin, Yi-Chun; Liu, Yuan-Hao; Nievaart, Sander; Chen, Yen-Fu; Wu, Shu-Wei; Chou, Wen-Tsae; Jiang, Shiang-Huei

    2011-10-01

    High energy photon (over 10 MeV) and neutron beams adopted in radiobiology and radiotherapy always produce mixed neutron/gamma-ray fields. The Mg(Ar) ionization chambers are commonly applied to determine the gamma-ray dose because of its neutron insensitive characteristic. Nowadays, many perturbation corrections for accurate dose estimation and lots of treatment planning systems are based on Monte Carlo technique. The Monte Carlo codes EGSnrc, FLUKA, GEANT4, MCNP5, and MCNPX were used to evaluate energy dependent response functions of the Exradin M2 Mg(Ar) ionization chamber to a parallel photon beam with mono-energies from 20 keV to 20 MeV. For the sake of validation, measurements were carefully performed in well-defined (a) primary M-100 X-ray calibration field, (b) primary 60Co calibration beam, (c) 6-MV, and (d) 10-MV therapeutic beams in hospital. At energy region below 100 keV, MCNP5 and MCNPX both had lower responses than other codes. For energies above 1 MeV, the MCNP ITS-mode greatly resembled other three codes and the differences were within 5%. Comparing to the measured currents, MCNP5 and MCNPX using ITS-mode had perfect agreement with the 60Co, and 10-MV beams. But at X-ray energy region, the derivations reached 17%. This work shows us a better insight into the performance of different Monte Carlo codes in photon-electron transport calculation. Regarding the application of the mixed field dosimetry like BNCT, MCNP with ITS-mode is recognized as the most suitable tool by this work.

  2. Quality-assurance results for field pH and specific-conductance measurements, and for laboratory analysis, National Atmospheric Deposition Program and National Trends Network; January 1980-September 1984

    USGS Publications Warehouse

    Schroder, L.J.; Brooks, M.H.; Malo, B.A.; Willoughby, T.C.

    1986-01-01

    Five intersite comparison studies for the field determination of pH and specific conductance, using simulated-precipitation samples, were conducted by the U.S.G.S. for the National Atmospheric Deposition Program and National Trends Network. These comparisons were performed to estimate the precision of pH and specific conductance determinations made by sampling-site operators. Simulated-precipitation samples were prepared from nitric acid and deionized water. The estimated standard deviation for site-operator determination of pH was 0.25 for pH values ranging from 3.79 to 4.64; the estimated standard deviation for specific conductance was 4.6 microsiemens/cm at 25 C for specific-conductance values ranging from 10.4 to 59.0 microsiemens/cm at 25 C. Performance-audit samples with known analyte concentrations were prepared by the U.S.G.S.and distributed to the National Atmospheric Deposition Program 's Central Analytical Laboratory. The differences between the National Atmospheric Deposition Program and national Trends Network-reported analyte concentrations and known analyte concentrations were calculated, and the bias and precision were determined. For 1983, concentrations of calcium, magnesium, sodium, and chloride were biased at the 99% confidence limit; concentrations of potassium and sulfate were unbiased at the 99% confidence limit. Four analytical laboratories routinely analyzing precipitation were evaluated in their analysis of identical natural- and simulated precipitation samples. Analyte bias for each laboratory was examined using analysis of variance coupled with Duncan 's multiple-range test on data produced by these laboratories, from the analysis of identical simulated-precipitation samples. Analyte precision for each laboratory has been estimated by calculating a pooled variance for each analyte. Interlaboratory comparability results may be used to normalize natural-precipitation chemistry data obtained from two or more of these laboratories. (Author

  3. Field Campaign Guidelines

    SciTech Connect

    Voyles, J. W.; Chapman, L. A.

    2015-12-01

    This document establishes a common set of guidelines for the Atmospheric Radiation Measurement (ARM) Climate Research Facility for planning, executing, and closing out field campaigns. The steps that guide individual field campaigns are described in the Field Campaign Tracking System and are specifically tailored to meet the scope of each field campaign.

  4. Specification Reformulation During Specification Validation

    NASA Technical Reports Server (NTRS)

    Benner, Kevin M.

    1992-01-01

    The goal of the ARIES Simulation Component (ASC) is to uncover behavioral errors by 'running' a specification at the earliest possible points during the specification development process. The problems to be overcome are the obvious ones the specification may be large, incomplete, underconstrained, and/or uncompilable. This paper describes how specification reformulation is used to mitigate these problems. ASC begins by decomposing validation into specific validation questions. Next, the specification is reformulated to abstract out all those features unrelated to the identified validation question thus creating a new specialized specification. ASC relies on a precise statement of the validation question and a careful application of transformations so as to preserve the essential specification semantics in the resulting specialized specification. This technique is a win if the resulting specialized specification is small enough so the user my easily handle any remaining obstacles to execution. This paper will: (1) describe what a validation question is; (2) outline analysis techniques for identifying what concepts are and are not relevant to a validation question; and (3) identify and apply transformations which remove these less relevant concepts while preserving those which are relevant.

  5. Exposure to a specific pulsed low-frequency magnetic field: A double-blind placebo-controlled study of effects on pain ratings in rheumatoid arthritis and fibromyalgia patients

    PubMed Central

    Shupak, Naomi M; McKay, Julia C; Nielson, Warren R; Rollman, Gary B; Prato, Frank S; Thomas, Alex W

    2006-01-01

    BACKGROUND Specific pulsed electromagnetic fields (PEMFs) have been shown to induce analgesia (antinociception) in snails, rodents and healthy human volunteers. OBJECTIVE The effect of specific PEMF exposure on pain and anxiety ratings was investigated in two patient populations. DESIGN A double-blind, randomized, placebo-controlled parallel design was used. METHOD The present study investigated the effects of an acute 30 min magnetic field exposure (less than or equal to 400 μTpk; less than 3 kHz) on pain (McGill Pain Questionnaire [MPQ], visual analogue scale [VAS]) and anxiety (VAS) ratings in female rheumatoid arthritis (RA) (n=13; mean age 52 years) and fibromyalgia (FM) patients (n=18; mean age 51 years) who received either the PEMF or sham exposure treatment. RESULTS A repeated measures analysis revealed a significant pre-post-testing by condition interaction for the MPQ Pain Rating Index total for the RA patients, F(1,11)=5.09, P<0.05, estimate of effect size = 0.32, power = 0.54. A significant pre-post-effect for the same variable was present for the FM patients, F(1,15=16.2, P<0.01, estimate of effect size = 0.52, power =0.96. Similar findings were found for MPQ subcomponents and the VAS (pain). There was no significant reduction in VAS anxiety ratings pre- to post-exposure for either the RA or FM patients. CONCLUSION These findings provide some initial support for the use of PEMF exposure in reducing pain in chronic pain populations and warrants continued investigation into the use of PEMF exposure for short-term pain relief. PMID:16770449

  6. Military specifications

    NASA Technical Reports Server (NTRS)

    Reynolds, Philip

    1987-01-01

    The current situation relative to the military specification is that there is not one specific model of turbulence which people are using. Particular disagreement exists on how turbulence levels will vary with qualitative analysis. It does not tie one down to specifics. When it comes to flying quality specifications, many feel that one should stay with the definitions of the Cooper-Harper rating scale but allow the levels to shift depending on the level of turbulence. There is a ride quality specification in the MIL-SPEC having to do with flight control systems design that is related to a turbulence model. This spec (MIL-F8785C) and others are discussed.

  7. High-sensitivity immunoassay with surface plasmon field-enhanced fluorescence spectroscopy using a plastic sensor chip: application to quantitative analysis of total prostate-specific antigen and GalNAcβ1-4GlcNAc-linked prostate-specific antigen for prostate cancer diagnosis.

    PubMed

    Kaya, Takatoshi; Kaneko, Tomonori; Kojima, Shun; Nakamura, Yukito; Ide, Youichi; Ishida, Kenji; Suda, Yoshihiko; Yamashita, Katsuko

    2015-02-03

    A high-sensitivity immunoassay system with surface plasmon field-enhanced fluorescence spectrometry (SPFS) was constructed using a plastic sensor chip and then applied to the detection of total prostate-specific antigen (total PSA) and GalNAcβ1-4GlcNAc-linked prostate-specific antigen (LacdiNAc-PSA) in serum, to discriminate between prostate cancer (PC) and benign prostate hyperplasia (BPH). By using this automated SPFS immunoassay, the detection limit for total PSA in serum was as low as 0.04 pg/mL, and the dynamic range was estimated to be at least five digits. A two-step sandwich SPFS immunoassay for LacdiNAc-PSA was constructed using both the anti-PSA IgG antibody to capture PSA and Wisteria floribunda agglutinin (WFA) for the detection of LacdiNAc. The results of the LacdiNAc-PSA immunoassay with SPFS showed that the assay had a sensitivity of 20.0 pg/mL and permitted the specific distinction between PC and BPH within the PSA gray zone. These results suggested that high-sensitivity automated SPFS immunoassay systems might become a powerful tool for the diagnosis of PC and other diseases.

  8. Comparison between Steroid Binding to Progesterone Membrane Receptor α (mPRα) and to Progesterone Nuclear Receptor: Correlation with Physicochemical Properties Assessed by Comparative Molecular Field Analysis and Identification of mPRα-specific Agonists

    PubMed Central

    Kelder, Jan; Azevedo, Rita; Pang, Yefei; de Vlieg, Jacob; Dong, Jing; Thomas, Peter

    2010-01-01

    Recent results showing that the binding characteristics of 33 steroids for human membrane progesterone receptor alpha (hu-mPRα) differ from those for the nuclear progesterone receptor (nPR) suggest that hu-mPRα-specific agonists can be identified for investigating its physiological functions. The binding affinities of an additional 21 steroids for hu-mPRα were determined to explore the structure-activity relationships in more detail and to identify potent, specific mPRα agonists. Four synthetic progesterone derivatives with methyl or methylene groups on positions 18 or 19, 18a-methylprogesterone (18-CH3P4, Org OE 64-0), 13-ethenyl-18-norprogesterone (18-CH2P4, Org 33663-0), 19a-methylprogesterone (19-CH3P4, Org OD 13-0) and 10-ethenyl-19-norprogesterone (19-CH2P4, Org OD 02-0), showed similar or higher affinities than progesterone for hu-mPRα and displayed mPRα agonist activities in G-protein and MAP kinase activation assays. All four steroids also bound to the nPR in cytosolic fractions of MCF-7 cells. However, two compounds, 19-CH2P4 and 19-CH3P4, showed no nPR agonist activity in a nPR reporter assay and therefore are selective mPRα agonists suitable for physiological investigations. The structure-binding relationships of the combined series of 54 steroids for hu-mPRα deviated strikingly from those of a published set of 60 3-keto or 3-desoxy steroids for nPR. Close correlations were observed between the receptor binding affinities of the steroids and their physicochemical properties calculated by comparative molecular field analysis (CoMFA) for both hu-mPRα and nPR. A comparison of the CoMFA field graphs for the two receptors revealed several differences in the structural features required for binding to hu-mPRα and nPR which could be exploited to develop additional mPR-specific ligands. PMID:20096719

  9. Facilities Specifications Guide.

    ERIC Educational Resources Information Center

    Athletic Business, 2000

    2000-01-01

    Provides line drawings of indoor and outdoor sporting fields reflecting the specifications and dimensional standards of each, including where additional information can be found. Sporting events from badminton, baseball, and basketball to lacrosse, swimming/diving, and volleyball are addressed. (GR)

  10. SU-E-T-594: Out-Of-Field Neutron and Gamma Dose Estimated Using TLD-600/700 Pairs in the Wobbling Proton Therapy System

    SciTech Connect

    Chen, Y; Lin, Y; Tsai, H

    2015-06-15

    Purpose: Secondary fast neutrons and gamma rays are mainly produced due to the interaction of the primary proton beam with the beam delivery nozzle. These secondary radiation dose to patients and radiation workers are unwanted. The purpose of this study is to estimate the neutron and gamma dose equivalent out of the treatment volume during the wobbling proton therapy system. Methods: Two types of thermoluminescent (TL) dosimeters, TLD-600 ({sup 6}LiF: Mg, Ti) and TLD-700 ({sup 7}LiF: Mg, Ti) were used in this study. They were calibrated in the standard neutron and gamma sources at National Standards Laboratory. Annealing procedure is 400°C for 1 hour, 100°C for 2 hours and spontaneously cooling down to the room temperature in a programmable oven. Two-peak method (a kind of glow curve analysis technique) was used to evaluate the TL response corresponding to the neutron and gamma dose. The TLD pairs were placed outside the treatment field at the neutron-gamma mixed field with 190-MeV proton beam produced by the wobbling system through the polyethylene plate phantom. The results of TLD measurement were compared to the Monte Carlo simulation. Results: The initial experiment results of calculated dose equivalents are 0.63, 0.38, 0.21 and 0.13 mSv per Gy outside the field at the distance of 50, 100, 150 and 200 cm. Conclusion: The TLD-600 and TLD-700 pairs are convenient to estimate neutron and gamma dosimetry during proton therapy. However, an accurate and suitable glow curve analysis technique is necessary. During the wobbling system proton therapy, our results showed that the neutron and gamma doses outside the treatment field are noticeable. This study was supported by the grants from the Chang Gung Memorial Hospital (CMRPD1C0682)

  11. Building Specifications

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The building in the top photo is the new home of the National Permanent Savings Bank in Washington, D.C., designed by Hartman-Cox Architects. Its construction was based on a money-saving method of preparing building specifications which derived from NASA technology developed to obtain quality construction while holding down cost of launch facilities, test centers and other structures. Written technical specifications spell out materials and components to be used on construction projects and identify the quality tests each item must pass. Specifications can have major impact on construction costs. Poorly formulated specifications can lead to unacceptable construction which must be replaced, unnecessarily high materials costs, safety hazards, disputes and often additional costs due to delays and litigation. NASA's Langley Research Center developed a novel approach to providing accurate, uniform, cost-effective specifications which can be readily updated to incorporate new building technologies. Called SPECSINTACT, it is a computerized - system accessible to all NASA centers involved in construction programs. The system contains a comprehensive catalog of master specifications applicable to many types of construction. It enables designers of any structure to call out relevant sections from computer storage and modify them to fit the needs of the project at hand. Architects and engineers can save time by concentrating their efforts on needed modifications rather than developing all specifications from scratch. Successful use of SPECSINTACT has led to a number of spinoff systems. One of the first was MASTERSPEC, developed from NASA's experience by Production Systems for Architects and Engineers, Inc., an organization established by the American Institute of Architects. MASTERSPEC, used in construction of the bank building pictured, follows the same basic format as SPECSINTACT and can be used in either automated or manual modes. The striking appearance of the bank

  12. Specifying Specification.

    PubMed

    Paulo, Norbert

    2016-03-01

    This paper tackles the accusation that applied ethics is no serious academic enterprise because it lacks theoretical bracing. It does so in two steps. In the first step I introduce and discuss a highly acclaimed method to guarantee stability in ethical theories: Henry Richardson's specification. The discussion shows how seriously ethicists take the stability of the connection between the foundational parts of their theories and their further development as well as their "application" to particular problems or cases. A detailed scrutiny of specification leads to the second step, where I use insights from legal theory to inform the debate around stability from that point of view. This view reveals some of specification's limitations. I suggest that, once specification is sufficiently specified, it appears astonishingly similar to deduction as used in legal theory. Legal theory also provides valuable insight into the functional range of deduction and its relation to other forms of reasoning. This leads to a richer understanding of stability in normative theories and to a smart division of labor between deduction and other forms of reasoning. The comparison to legal theory thereby provides a framework for how different methods such as specification, deduction, balancing, and analogy relate to one another.

  13. Exposure to high- and low-light conditions in an open-field test of anxiety increases c-Fos expression in specific subdivisions of the rat basolateral amygdaloid complex.

    PubMed

    Hale, Matthew W; Bouwknecht, J Adriaan; Spiga, Francesca; Shekhar, Anantha; Lowry, Christopher A

    2006-12-11

    Anxiety states and anxiety-related behaviors appear to be regulated by a distributed and highly interconnected system of forebrain structures including the basolateral amygdaloid complex (basolateral amygdala). Despite a wealth of research examining the role of the basolateral amygdala in anxiety-related behaviors and anxiety states, the specific subdivisions of the basolateral amygdala that are involved in responses to anxiogenic stimuli have not been examined. In this study, we investigated the effects of exposure to a novel open-field environment, with either low- or high-levels of illumination, on expression of the protein product of the immediate-early gene c-Fos in subdivisions of the rat basolateral amygdala. The subdivisions studied included the lateral, ventrolateral and ventromedial parts of the lateral amygdaloid nucleus, the anterior, posterior and ventral parts of the basolateral amygdaloid nucleus and the anterior and posterior part of the basomedial amygdaloid nucleus. Small increases in the number of c-Fos-immunoreactive cells were observed in several, but not all, of the subdivisions of the basolateral amygdala studied following exposure of rats to either the high- or low-light conditions, compared to home cage or handled control groups. Open-field exposure in both the high- and low-light conditions resulted in a marked increase in c-Fos expression in the anterior part of the basolateral amygdaloid nucleus compared to either home cage or handled control groups. These findings point toward anatomical and functional heterogeneity within the basolateral amygdaloid complex and an important role of the anterior part of the basolateral amygdaloid nucleus in the neural mechanisms underlying physiological or behavioral responses to this anxiety-related stimulus.

  14. Ni-impurity effects on the superconducting gap of La2-xSrxCuO4 studied from the magnetic field and temperature dependence of the electronic specific heat

    NASA Astrophysics Data System (ADS)

    Kurosawa, T.; Momono, N.; Oda, M.; Ido, M.

    2012-04-01

    The magnetic field and temperature dependence of the electronic specific heat Cel have been systematically investigated in La2-xSrxCu1-yNiyO4 (LSCNO) in order to study Ni-impurity effects on the superconducting (SC) gap. In LSCNO with x = 0.15 and y = 0.015, the value of γ (≡Cel/T) at T = 0 K, γ0, is enhanced under the magnetic field H applied along the c axis. The increment of γ0, Δγ0, follows the Volovik relation Δγ0 = AH, characteristic of the SC gap with line nodes, with prefactor A similar to that of a pure sample. The Cel/T versus T curve under H = 0 shows a d-wave-like SC anomaly with an abrupt increase at Tc and T-linear dependence at T ≪ Tc, although the γ0-value in the Cel/T versus T curve increases with increasing Ni concentrations. Interestingly, as the SC part of Cel/T, Cel/T - γ0 ≡ γs, decreases in LSCNO, Tc is reduced in proportion to the decrease of γs. These findings can be explained phenomenologically by a simple model in which Ni impurities bring about strong pair breaking at the edges of the coherent nodal part of the Fermi surface but in the vicinity of the nodes of the SC gap. The reduction of the SC condensation energy U0 in LSCNO, evaluated from Cel at T≲Tc, is also understood by the same model.

  15. Specific Suspicion

    ERIC Educational Resources Information Center

    Taylor, Kelley R.

    2009-01-01

    This article discusses a recent case decided by the U.S. Supreme Court which highlights the importance of having specific suspicions of misbehavior before conducting a strip search. The case involves an eighth-grade female student who was being strip-searched by a middle school assistant principal, a school nurse, and an administrative assistant…

  16. Specific Suspicion

    ERIC Educational Resources Information Center

    Taylor, Kelley R.

    2009-01-01

    This article discusses a recent case decided by the U.S. Supreme Court which highlights the importance of having specific suspicions of misbehavior before conducting a strip search. The case involves an eighth-grade female student who was being strip-searched by a middle school assistant principal, a school nurse, and an administrative assistant…

  17. Testing the Effects of DL-Alpha-Tocopherol Supplementation on Oxidative Damage, Total Antioxidant Protection and the Sex-Specific Responses of Reproductive Effort and Lifespan to Dietary Manipulation in Australian Field Crickets (Teleogryllus commodus).

    PubMed

    Archer, C Ruth; Hempenstall, Sarah; Royle, Nick J; Selman, Colin; Willis, Sheridan; Rapkin, James; Blount, Jon D; Hunt, John

    2015-12-04

    The oxidative stress theory predicts that the accumulation of oxidative damage causes aging. More generally, oxidative damage could be a cost of reproduction that reduces survival. Both of these hypotheses have mixed empirical support. To better understand the life-history consequences of oxidative damage, we fed male and female Australian field crickets (Teleogryllus commodus) four diets differing in their protein and carbohydrate content, which have sex-specific effects on reproductive effort and lifespan. We supplemented half of these crickets with the vitamin E isoform DL-alpha-tocopherol and measured the effects of nutrient intake on lifespan, reproduction, oxidative damage and antioxidant protection. We found a clear trade-off between reproductive effort and lifespan in females but not in males. In direct contrast to the oxidative stress theory, crickets fed diets that improved their lifespan had high levels of oxidative damage to proteins. Supplementation with DL-alpha-tocopherol did not significantly improve lifespan or reproductive effort. However, males fed diets that increased their reproductive investment experienced high oxidative damage to proteins. While this suggests that male reproductive effort could elevate oxidative damage, this was not associated with reduced male survival. Overall, these results provide little evidence that oxidative damage plays a central role in mediating life-history trade-offs in T. commodus.

  18. Testing the Effects of dl-Alpha-Tocopherol Supplementation on Oxidative Damage, Total Antioxidant Protection and the Sex-Specific Responses of Reproductive Effort and Lifespan to Dietary Manipulation in Australian Field Crickets (Teleogryllus commodus)

    PubMed Central

    Archer, C. Ruth; Hempenstall, Sarah; Royle, Nick J.; Selman, Colin; Willis, Sheridan; Rapkin, James; Blount, Jon D.; Hunt, John

    2015-01-01

    The oxidative stress theory predicts that the accumulation of oxidative damage causes aging. More generally, oxidative damage could be a cost of reproduction that reduces survival. Both of these hypotheses have mixed empirical support. To better understand the life-history consequences of oxidative damage, we fed male and female Australian field crickets (Teleogryllus commodus) four diets differing in their protein and carbohydrate content, which have sex-specific effects on reproductive effort and lifespan. We supplemented half of these crickets with the vitamin E isoform dl-alpha-tocopherol and measured the effects of nutrient intake on lifespan, reproduction, oxidative damage and antioxidant protection. We found a clear trade-off between reproductive effort and lifespan in females but not in males. In direct contrast to the oxidative stress theory, crickets fed diets that improved their lifespan had high levels of oxidative damage to proteins. Supplementation with dl-alpha-tocopherol did not significantly improve lifespan or reproductive effort. However, males fed diets that increased their reproductive investment experienced high oxidative damage to proteins. While this suggests that male reproductive effort could elevate oxidative damage, this was not associated with reduced male survival. Overall, these results provide little evidence that oxidative damage plays a central role in mediating life-history trade-offs in T. commodus. PMID:26783958

  19. Optimization of a Fast Neutron Scintillator for Real-Time Pulse Shape Discrimination in the Transient Reactor Test Facility (TREAT) Hodoscope

    SciTech Connect

    Johnson, James T.; Thompson, Scott J.; Watson, Scott M.; Chichester, David L.

    2016-11-01

    We present a multi-channel, fast neutron/gamma ray detector array system that utilizes ZnS(Ag) scintillator detectors. The system employs field programmable gate arrays (FPGAs) to do real-time all digital neutron/gamma ray discrimination with pulse height and time histograms to allow count rates in excess of 1,000,000 pulses per second per channel. The system detector number is scalable in blocks of 16 channels.

  20. A field-grown transgenic tomato line expressing higher levels of polyamines reveals legume cover crop mulch-specific perturbations in fruit phenotype at the levels of metabolite profiles, gene expression, and agronomic characteristics.

    PubMed

    Neelam, Anil; Cassol, Tatiana; Mehta, Roshni A; Abdul-Baki, Aref A; Sobolev, Anatoli P; Goyal, Ravinder K; Abbott, Judith; Segre, Anna L; Handa, Avtar K; Mattoo, Autar K

    2008-01-01

    Genetic modification of crop plants to introduce desirable traits such as nutritional enhancement, disease and pest resistance, and enhanced crop productivity is increasingly seen as a promising technology for sustainable agriculture and boosting food production in the world. Independently, cultural practices that utilize alternative agriculture strategies including organic cultivation subscribe to sustainable agriculture by limiting chemical usage and reduced tillage. How the two together affect fruit metabolism or plant growth in the field or whether they are compatible has not yet been tested. Fruit-specific yeast S-adenosylmethionine decarboxylase (ySAMdc) line 579HO, and a control line 556AZ were grown in leguminous hairy vetch (Vicia villosa Roth) (HV) mulch and conventional black polyethylene (BP) mulch, and their fruit analysed. Significant genotypexmulch-dependent interactions on fruit phenotype were exemplified by differential profiles of 20 fruit metabolites such as amino acids, sugars, and organic acids. Expression patterns of the ySAMdc transgene, and tomato SAMdc, E8, PEPC, and ICDHc genes were compared between the two lines as a function of growth on either BP or HV mulch. HV mulch significantly stimulated the accumulation of asparagine, glutamate, glutamine, choline, and citrate concomitant with a decrease in glucose in the 556AZ fruits during ripening as compared to BP. It enables a metabolic system in tomato somewhat akin to the one in higher polyamine-accumulating transgenic fruit that have higher phytonutrient content. Finally, synergism was found between HV mulch and transgenic tomato in up-regulating N:C indicator genes PEPC and ICDHc in the fruit.

  1. A field-grown transgenic tomato line expressing higher levels of polyamines reveals legume cover crop mulch-specific perturbations in fruit phenotype at the levels of metabolite profiles, gene expression, and agronomic characteristics

    PubMed Central

    Neelam, Anil; Cassol, Tatiana; Mehta, Roshni A.; Abdul-Baki, Aref A.; Sobolev, Anatoli P.; Goyal, Ravinder K.; Abbott, Judith; Segre, Anna L.; Handa, Avtar K.; Mattoo, Autar K.

    2008-01-01

    Genetic modification of crop plants to introduce desirable traits such as nutritional enhancement, disease and pest resistance, and enhanced crop productivity is increasingly seen as a promising technology for sustainable agriculture and boosting food production in the world. Independently, cultural practices that utilize alternative agriculture strategies including organic cultivation subscribe to sustainable agriculture by limiting chemical usage and reduced tillage. How the two together affect fruit metabolism or plant growth in the field or whether they are compatible has not yet been tested. Fruit-specific yeast S-adenosylmethionine decarboxylase (ySAMdc) line 579HO, and a control line 556AZ were grown in leguminous hairy vetch (Vicia villosa Roth) (HV) mulch and conventional black polyethylene (BP) mulch, and their fruit analysed. Significant genotype×mulch-dependent interactions on fruit phenotype were exemplified by differential profiles of 20 fruit metabolites such as amino acids, sugars, and organic acids. Expression patterns of the ySAMdc transgene, and tomato SAMdc, E8, PEPC, and ICDHc genes were compared between the two lines as a function of growth on either BP or HV mulch. HV mulch significantly stimulated the accumulation of asparagine, glutamate, glutamine, choline, and citrate concomitant with a decrease in glucose in the 556AZ fruits during ripening as compared to BP. It enables a metabolic system in tomato somewhat akin to the one in higher polyamine-accumulating transgenic fruit that have higher phytonutrient content. Finally, synergism was found between HV mulch and transgenic tomato in up-regulating N:C indicator genes PEPC and ICDHc in the fruit. PMID:18469323

  2. Fasciola hepatica: Specificity of a coproantigen ELISA test for diagnosis of fasciolosis in faecal samples from cattle and sheep concurrently infected with gastrointestinal nematodes, coccidians and/or rumen flukes (paramphistomes), under field conditions.

    PubMed

    Kajugu, P-E; Hanna, R E B; Edgar, H W; McMahon, C; Cooper, M; Gordon, A; Barley, J P; Malone, F E; Brennan, G P; Fairweather, I

    2015-09-15

    Chronic fasciolosis is often diagnosed by faecal egg counting (FEC), following concentration of the eggs in the sample by a zinc sulphate floatation method. However, concentration by a sedimentation technique gives improved sensitivity. Interpretation of FEC results for fasciolosis is complicated by factors such as the long pre-patent period and irregular egg shedding. Thus, FEC reduction tests (FECRT), when used alone, are not completely reliable for diagnosis of anthelmintic susceptibility or resistance in local fluke populations, especially when parasite burdens are small. A Fasciola hepatica coproantigen ELISA test has been introduced which more accurately reflects the presence of flukes in the host bile ducts in late pre-patent infections, and absence of flukes following successful chemotherapeutic intervention. The aim of the present study was to elucidate the specificity of the F. hepatica coproantigen ELISA technique, particularly regarding potential cross-reactivity with rumen fluke (paramphistome), gastrointestinal nematode and coccidian infections. The method involved parallel testing of a large battery of faecal samples from field-infected cattle and sheep using floatation and sedimentation FECs and coproantigen analysis. No evidence was found for significant false positivity in the F. hepatica coproantigen ELISA due to paramphistome, coccidian and/or gastrointestinal nematode co-infections. With sedimentation FECs less than 10 F. hepatica eggs per gram (epg), the likelihood of a positive coproantigen result for the sample progressively decreased. Diagnosis of fasciolosis should be based on consideration of both FEC and coproantigen ELISA findings, to ensure optimum sensitivity for pre-patent and low-level infections.

  3. Electric Field Imaging Project

    NASA Technical Reports Server (NTRS)

    Wilcutt, Terrence; Hughitt, Brian; Burke, Eric; Generazio, Edward

    2016-01-01

    NDE historically has focused technology development in propagating wave phenomena with little attention to the field of electrostatics and emanating electric fields. This work is intended to bring electrostatic imaging to the forefront of new inspection technologies, and new technologies in general. The specific goals are to specify the electric potential and electric field including the electric field spatial components emanating from, to, and throughout volumes containing objects or in free space.

  4. Specific phobias.

    PubMed

    Hamm, Alfons O

    2009-09-01

    Exposure based treatments in which patients are systematically confronted with their feared objects of situations are highly effective in the treatment of specific phobias and produce stable improvement both in reported fear and behavioral avoidance. Exposure in reality is more effective in most cases than exposure in sensu. For situations that are difficult to realize, exposure in virtual environments has become increasingly valuable. Exposure in vivo is clearly superior to pharmacotherapy, although cognitive enhancers have been successfully used recently to increase the effect of exposure therapy. The induction of relaxation is not a necessary precondition for exposure therapy. Rather the current mechanisms of change focus on extinction learning as being the central mechanism both on a cognitive level namely that the feared object is no longer associated with severely threatening consequence but also on an affective level, meaning that feared cue is no longer capable to activate the fear circuit in the brain. Accordingly future diagnostic categorizations of phobic disorders in the DSM-V should rather focus on the pattern of the fear response that needs to be changed than on the eliciting cues or situations that are avoided.

  5. Intent Specifications

    NASA Technical Reports Server (NTRS)

    Leveson, Nancy G.

    1995-01-01

    We have been investigating the implications of using abstractions based on intent rather than the aggregation and information-hiding abstractions commonly used in software en- gineering: Cognitive psychologists have shown that intent abstraction is consistent with human problem-solving processes. We believe that new types of specifications and designs based on this concept can assist in understanding and specifying requirements, capturing the most important design rationale information in an efficient and economical way, and supporting the process of identifying and analyzing required changes to minimize the introduction of errors. The goal of hierarchical abstraction is to allow both top-down and bottom-up reasoning about a complex system. In computer science, we have made much use of (1) part-whole abstractions where each level of a hierarchy represents an aggregation of the components at a lower level and of (2) information-hiding abstractions where each level contains the same conceptual information but hides some details about the concepts, that is, each level is a refinement of the information at a higher level.

  6. Magnetic field generator

    DOEpatents

    Krienin, Frank

    1990-01-01

    A magnetic field generating device provides a useful magnetic field within a specific retgion, while keeping nearby surrounding regions virtually field free. By placing an appropriate current density along a flux line of the source, the stray field effects of the generator may be contained. One current carrying structure may support a truncated cosine distribution, and it may be surrounded by a current structure which follows a flux line that would occur in a full coaxial double cosine distribution. Strong magnetic fields may be generated and contained using superconducting cables to approximate required current surfaces.

  7. A Specification Translation from Behavioral Specifications to Rewrite Specifications

    NASA Astrophysics Data System (ADS)

    Nakamura, Masaki; Kong, Weiqiang; Ogata, Kazuhiro; Futatsugi, Kokichi

    There are two ways to describe a state machine as an algebraic specification: a behavioral specification and a rewrite specification. In this study, we propose a translation system from behavioral specifications to rewrite specifications to obtain a verification system which has the strong points of verification techniques for both specifications. Since our translation system is complete with respect to invariant properties, it helps us to obtain a counter-example for an invariant property through automatic exhaustive searching for a rewrite specification.

  8. Component-specific modeling

    NASA Technical Reports Server (NTRS)

    Mcknight, R. L.

    1985-01-01

    A series of interdisciplinary modeling and analysis techniques that were specialized to address three specific hot section components are presented. These techniques will incorporate data as well as theoretical methods from many diverse areas including cycle and performance analysis, heat transfer analysis, linear and nonlinear stress analysis, and mission analysis. Building on the proven techniques already available in these fields, the new methods developed will be integrated into computer codes to provide an accurate, and unified approach to analyzing combustor burner liners, hollow air cooled turbine blades, and air cooled turbine vanes. For these components, the methods developed will predict temperature, deformation, stress and strain histories throughout a complete flight mission.

  9. High electric field phenomena in insulation

    NASA Astrophysics Data System (ADS)

    Laghari, J. R.; Sarjeant, W. J.

    1989-01-01

    The present study extends previous work to include electron radiation-induced changes in monoisopropyl biphenyl (MIPB)-impregnated polypropylene film as well as the effects of neutron/gamma radiation on dry polypropylene films. Effects that were quite similar were induced by both electron and neutron radiation on the properties of interest of the polypropylene films. Impregnation of the film with MIPB had a mitigatory effect on the degradation of the properties. This report also contains the results of a simultaneous electrical and thermal aging study of a capacitor-grade polypropylene film. The data obtained in this study was fitted to models that will enable realistic prediction of lifetimes under operating conditions.

  10. Psychological Assessment of Patrolman Qualifications in Relation to Field Performance; The Identification of Predictors for Overall Performance of Patrolmen and the Relation between Predictors and Specific Patterns of Exceptional and Marginal Performance.

    ERIC Educational Resources Information Center

    Chicago Police Dept., IL.

    Behavioral scientists have been slow in the development of effective procedures and in empirical validation of psychological testing instruments for selecting law enforcement personnel. This study involved 253 supervisory sergeants and field lieutenants and 2,327 uniformed patrolmen of the Chicago Police Department (CPD). Three major performance…

  11. Field emission chemical sensor

    DOEpatents

    Panitz, J.A.

    1983-11-22

    A field emission chemical sensor for specific detection of a chemical entity in a sample includes a closed chamber enclosing two field emission electrode sets, each field emission electrode set comprising (a) an electron emitter electrode from which field emission electrons can be emitted when an effective voltage is connected to the electrode set; and (b) a collector electrode which will capture said electrons emitted from said emitter electrode. One of the electrode sets is passive to the chemical entity and the other is active thereto and has an active emitter electrode which will bind the chemical entity when contacted therewith.

  12. Organ-Specific Differential NMR-Based Metabonomic Analysis of Soybean [Glycine max (L.) Merr.] Fruit Reveals the Metabolic Shifts and Potential Protection Mechanisms Involved in Field Mold Infection.

    PubMed

    Deng, Jun-Cai; Yang, Cai-Qiong; Zhang, Jing; Zhang, Qing; Yang, Feng; Yang, Wen-Yu; Liu, Jiang

    2017-01-01

    Prolonged, continuous rainfall is the main climatic characteristic of autumn in Southwest China, and it has been found to cause mildew outbreaks in pre-harvest soybean fields. Low temperature and humidity (LTH) stress during soybean maturation in the field promotes pre-harvest mildew, resulting in damage to different organs of soybean fruits to different extents, but relatively little information on the resistance mechanisms in these fruits is available. Therefore, to understand the metabolic responses of soybean fruits to field mold (FM), the metabonomic variations induced by LTH were characterized using proton nuclear magnetic resonance spectroscopy ((1)H-NMR), and the primary metabolites from the pod, seed coat and cotyledon of pre-harvest soybean were quantified. Analysis of FM-damaged soybean germplasms with different degrees of resistance to FM showed that extracts were dominated by 66 primary metabolites, including amino acids, organic acids and sugars. Each tissue had a characteristic metabolic profile, indicating that the metabolism of proline in the cotyledon, lysine in the seed coat, and sulfur in the pod play important roles in FM resistance. The primary-secondary metabolism interface and its potential contribution to FM resistance was investigated by targeted analyses of secondary metabolites. Both the seed coat and the pod have distinct but nonexclusive metabolic responses to FM, and these are functionally integrated into FM resistance mechanisms.

  13. Organ-Specific Differential NMR-Based Metabonomic Analysis of Soybean [Glycine max (L.) Merr.] Fruit Reveals the Metabolic Shifts and Potential Protection Mechanisms Involved in Field Mold Infection

    PubMed Central

    Deng, Jun-cai; Yang, Cai-qiong; Zhang, Jing; Zhang, Qing; Yang, Feng; Yang, Wen-yu; Liu, Jiang

    2017-01-01

    Prolonged, continuous rainfall is the main climatic characteristic of autumn in Southwest China, and it has been found to cause mildew outbreaks in pre-harvest soybean fields. Low temperature and humidity (LTH) stress during soybean maturation in the field promotes pre-harvest mildew, resulting in damage to different organs of soybean fruits to different extents, but relatively little information on the resistance mechanisms in these fruits is available. Therefore, to understand the metabolic responses of soybean fruits to field mold (FM), the metabonomic variations induced by LTH were characterized using proton nuclear magnetic resonance spectroscopy (1H-NMR), and the primary metabolites from the pod, seed coat and cotyledon of pre-harvest soybean were quantified. Analysis of FM-damaged soybean germplasms with different degrees of resistance to FM showed that extracts were dominated by 66 primary metabolites, including amino acids, organic acids and sugars. Each tissue had a characteristic metabolic profile, indicating that the metabolism of proline in the cotyledon, lysine in the seed coat, and sulfur in the pod play important roles in FM resistance. The primary-secondary metabolism interface and its potential contribution to FM resistance was investigated by targeted analyses of secondary metabolites. Both the seed coat and the pod have distinct but nonexclusive metabolic responses to FM, and these are functionally integrated into FM resistance mechanisms. PMID:28487702

  14. PANDORA, a large volume low-energy neutron detector with real-time neutron-gamma discrimination

    NASA Astrophysics Data System (ADS)

    Stuhl, L.; Sasano, M.; Yako, K.; Yasuda, J.; Baba, H.; Ota, S.; Uesaka, T.

    2017-09-01

    The PANDORA (Particle Analyzer Neutron Detector Of Real-time Acquisition) system, which was developed for use in inverse kinematics experiments with unstable isotope beams, is a neutron detector based on a plastic scintillator coupled to a digital readout. PANDORA can be used for any reaction study involving the emission of low energy neutrons (100 keV-10 MeV) where background suppression and an increased signal-to-noise ratio are crucial. The digital readout system provides an opportunity for pulse shape discrimination (PSD) of the detected particles as well as intelligent triggering based on PSD. The figure of merit results of PANDORA are compared to the data in literature. Using PANDORA, 91 ± 1% of all detected neutrons can be separated, while 91 ± 1% of the detected gamma rays can be excluded, reducing the gamma ray background by one order of magnitude.

  15. Effect of fast neutron, gamma-ray and combined radiations on the thermal decomposition of ammonium perchlorate single crystals

    NASA Technical Reports Server (NTRS)

    Herley, P. J.; Wang, C. S.; Varsi, G.; Levy, P. W.

    1974-01-01

    The thermal decomposition kinetics have been determined for ammonium perchlorate crystals subjected to a fast neutron irradiation or to a fast neutron irradiation followed by a gamma-ray irradiation. Qualitatively, the radiation induced changes are similar to those obtained in this and in previous studies, with samples exposed only to gamma rays. The induction period is shortened and the rate constants, obtained from an Avrami-Erofeyev kinetic analysis, are modified. The acceleratory period constant increases and the decay period constant decreases. When compared on an equal deposited energy basis, the fast neutron induced changes are appreciably larger than the gamma-ray induced changes. Some, or all, of the fast neutron induced effects might be attributable to the introduction of localized regions of concentrated radiation damage ('spikes') by lattice atom recoils which become thermal decomposition sites when the crystals are heated.

  16. FaNGaS: a New Instrument for Fast Neutron Gamma Spectroscopy at FRM II Research Reactor at Garching

    SciTech Connect

    Randriamalala, T.; Rossbach, M.; Genreith, C.; Revay, Zs.; Kudejova, P.; Soellradl, S.; Wagner, F.M.

    2015-07-01

    For the identification and quantification of actinides in radioactive packages, the non-destructive method of Prompt-Gamma Activation Analysis (PGAA) is applied. To investigate the inelastic (n, n 'γ) scattering, a new instrumentation was installed at the FRM II research reactor. It is designed to exploit the 10{sup 8} cm{sup -2}s{sup -1} neutrons at an average neutron energy of 1.9 MeV delivered by the SR10 beam line. The outgoing prompt γ-rays are measured utilizing a 50% efficiency HPGe detector. Since the cross sections are expected to be low for such a process, two related factors had to be taken into account for the design of the instrumentation: the high beam intensity at the sample position and the high signal-to-background ratio seen by the detector. Eventual low energy neutrons due to the multiple scatterings through the beam line can be minimized using collimators in the beam tube. This has also an effect to a prior neutrons and photons background reduction of the experimental environment. A higher efficiency of the counting can be achieved by the lowering of background at the detector. In this case, a heavy shielding for both neutrons and photons, is designed around the detector while optimizing the sample-detector distance. Monte-Carlo simulation studies were conducted to effectively design the fast neutron beam collimators and the detector shield. A detailed description of the setup characterization and results from simulations and experimental measurements will be discussed through this contribution. (authors)

  17. Component specific modeling

    NASA Technical Reports Server (NTRS)

    Maffeo, R. J.; Mcknight, R. L.; Tipton, M. T.; Weber, G.

    1986-01-01

    The overall objective of this program is to develop and verify a series of interdisciplinary modeling and analysis techniques that were specialized to address three specific hot section components. These techniques incorporate data as well as theoretical methods from many diverse areas including cycle and performance analysis, heat transfer analysis, linear and nonlinear stress analysis, and mission analysis. Building on the proven techniques already available in these fields, the new methods developed are integrated to provide an accurate, efficient, and unified approach to analyzing combustor burner liners, hollow air-cooled turbine blades, and air-cooled turbine vanes. For these components, the methods developed predict temperature, deformation, stress, and strain histories throughout a complete flight mission.

  18. Component-specific modeling

    NASA Technical Reports Server (NTRS)

    Mcknight, R. L.

    1984-01-01

    A series of interdisciplinary modeling and analysis techniques that were specialized to address three specific hot section components are presented. These techniques will incorporate data as well as theoretical methods from many diverse areas including cycle and performance analysis, heat transfer analysis, linear and nonlinear stress analysis, and mission analysis. Building on the proven techniques already available in these fields, the new methods developed will be integrated into computer codes to provide an accurate, efficient and unified approach to analyzing combustor burner liners, hollow air-cooled turbine blades and air-cooled turbine vanes. For these components, the methods developed will predict temperature, deformation, stress and strain histories throughout a complete flight mission.

  19. Thermal effects of high-field (1.5 tesla) magnetic resonance imaging of the spine. Clinical experience above a specific absorption rate of 0.4 W/kg.

    PubMed

    Shellock, F G; Schaefer, D J; Grundfest, W; Crues, J V

    1986-01-01

    Current safety guidelines recommend limiting the exposure to radiofrequency (RF) radiation used for clinical magnetic resonance imaging to a whole body average specific absorption rate (SAR) of 0.4 W/kg. Since it may be desirable to image with SARs that exceed this level during MRI of the spine, we evaluated the thermal responses associated with these procedures. Body and skin temperatures were determined in 25 patients immediately before and after MRI. Since the eye is particularly susceptible to thermal injury, corneal temperature was also measured. High-resolution thermography was performed on three subjects to evaluate the surface heating pattern and identify potential thermal 'hot spots'. A 1.5 tesla/64 MHz MRI system with quadrature transmission and reception was used iN this study. The whole body average specific absorption rate ranged from 0.5 to 1.3 W/kg. Ambient conditions were room temperature 20-24 degrees C and relative humidity between 40 and 50 per cent. There was a slight but statistically significant (p less than 0.01) increase in body temperature after MRI (36.5 +/- 0.4 to 36.7 +/- 0.4 degrees C). Temperatures of the hand (30.4 +/- 1.4 to 31.2 +/- 1.0 degrees C), positioning isocenter (32.1 +/- 0.6 to 32.9 +/- 0.5), and cornea (32.5 +/- 0.6 to 32.9 +/- 0.5 degrees C) also increased a statistically significant amount. Thermographic imaging revealed normal heating patterns with no surface 'hot spots'. We conclude that the temperature changes associated with MRI of the spine at the SARs we studied were well below known thresholds for adverse effects and do not appear to be harmful to patients.

  20. Evaluation of Anti-A/Udorn/307/1972 Antibody Specificity to Influenza A/H3N2 Viruses Using an Evanescent-Field Coupled Waveguide-Mode Sensor

    PubMed Central

    Gopinath, Subash C. B.; Awazu, Koichi; Fujimaki, Makoto; Shimizu, Kazufumi

    2013-01-01

    Discrimination of closely related strains is a key issue, particularly for infectious diseases whose incidence fluctuates according to variations in the season and evolutionary changes. Among infectious diseases, influenza viral infections are a worldwide cause of pandemic disease and mortality. With the emergence of different influenza strains, it is vital to develop a method using antibodies that can differentiate between viral types and subtypes. Ideally, such a system would also be user friendly. In this study, a polyclonal antibody generated against A/Udorn/307/1972 (H3N2) was used as a probe to distinguish between influenza H3N2 viruses based on the interaction between the antibody and hemagglutinin, demonstrating its applicability for viral discrimination. Clear discrimination was demonstrated using an evanescent-field-coupled waveguide-mode sensor, which has appealing characteristics over other methods in the viewpoint of improving the sensitivity, measurement time, portability and usability. Further supporting evidence was obtained using enzyme-linked immunosorbent assays, hemagglutination-inhibition assays, and infectivity neutralization assays. The results obtained indicate that the polyclonal antibody used here is a potential probe for distinguishing influenza viruses and, with the aid of a handheld sensor it could be used for influenza surveillance. PMID:24339924

  1. Field Evaluation of a Combination of Monospecific Enzyme-Linked Immunosorbent Assays for Type-Specific Diagnosis of Human Immunodeficiency Virus Type 1 (HIV-1) and HIV-2 Infections in HIV-Seropositive Persons in Abidjan, Ivory Coast

    PubMed Central

    Nkengasong, John N.; Maurice, Chantal; Koblavi, Stéphania; Kalou, Mireille; Bile, Celestin; Yavo, Daniel; Boateng, Emmanuel; Wiktor, Stefan Z.; Greenberg, Alan E.

    1998-01-01

    reagent cost for the CME strategy was 59% lower than the cost of the Peptilav strategy. These results suggest that a combination of highly sensitive and specific commercially available monospecific ELISAs is a reliable and cost-effective strategy for type-specific serodiagnosis of HIV-1 and HIV-2 infections in HIV-seropositive persons and therefore represents a recommended strategy in areas where both HIV-1 and HIV-2 are endemic. PMID:9431934

  2. Evaluation of gadobutrol, a macrocyclic, nonionic gadolinium chelate in a brain glioma model: comparison with gadoterate meglumine and gadopentetate dimeglumine at 1.5 T, combined with an assessment of field strength dependence, specifically 1.5 versus 3 T.

    PubMed

    Attenberger, Ulrike I; Runge, Val M; Morelli, John N; Williams, Jonathan; Jackson, Carney B; Michaely, Henrik J

    2010-03-01

    To evaluate in a rat brain glioma model intraindividual tumor enhancement at 1.5 T using gadobutrol (Gadovist), a nonionic, macrocyclic chelate currently in clinical trials in the United States, in comparison with both an ionic macrocyclic chelate, gadoterate meglumine (Dotarem), and an ionic linear chelate, gadopentetate dimeglumine (Magnevist), and to compare the degree of tumor enhancement with gadobutrol at 1.5 and 3 T. A total of 24 rats, divided into three groups with n = 8 animals per group, were evaluated. Animals in group 1 received injections of gadobutrol and gadopentetate dimeglumine, whereas those in group 2 received gadobutrol and gadoterate meglumine. Injections were performed in random order and separated by 24 hours. Magnetic resonance imaging (MRI) examinations were performed immediately following each contrast injection with a 1.5 T MR system. Animals in group 3 received gadobutrol injections using the same protocol but with scans performed at 1.5 and 3 T. In all examinations, T1-weighted images were acquired precontrast, 1 minute postcontrast, and at 4 consecutive 2-minute intervals thereafter. A contrast dose of 0.1 mmol/kg was used in all instances. In groups 1 and 2, tumor signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were higher for gadobutrol compared to both other agents at each timepoint postcontrast injection. The improvement in tumor CNR with gadobutrol, depending on time, was between 12% and 40% versus gadopentetate dimeglumine, with the difference achieving statistical significance at 7 minutes. The improvement in tumor CNR with gadobutrol, depending on time, was between 15% and 27% versus gadoterate meglumine, with the difference statistically significant at 5 and 9 minutes. In group 3 the improvement in tumor SNR and CNR seen with the increase in field strength from 1.5 to 3 T for gadobutrol was statistically significant at all acquired timepoints (P < 0.002). CNR mean values ranged from 10.4 +/- 2.9 to 24.6 +/- 5

  3. Field Trip.

    ERIC Educational Resources Information Center

    Sanders, Bill

    1993-01-01

    Reports the results of a field trip to measure the intensity of electromagnetic fields generated by electronic devices in the home, in cars, at work, outside, and in places people visit during the day. Found that a person gets more intense exposure while working at a computer than by living next to an electrical substation. (MDH)

  4. Field Trip.

    ERIC Educational Resources Information Center

    Sanders, Bill

    1993-01-01

    Reports the results of a field trip to measure the intensity of electromagnetic fields generated by electronic devices in the home, in cars, at work, outside, and in places people visit during the day. Found that a person gets more intense exposure while working at a computer than by living next to an electrical substation. (MDH)

  5. Is there really a pot of gold at the end of the rainbow? Has the Occupational Specific Dispensation, as a mechanism to attract and retain health workers in South Africa, leveled the playing field?

    PubMed Central

    2012-01-01

    Background South Africa is experiencing a critical shortage of human resources for health (HRH) at a time when the population and the burden of ill-health, primarily due to HIV, AIDS and TB, are on the increase. This shortage is particularly severe within the nursing profession, which has witnessed significant emigration due to poor domestic working conditions and remuneration. Salaries and other benefits are an obvious pull factor towards foreign countries, given the often extreme international wage differentials. The introduction of the Occupation Specific Dispensation (OSD) in 2007 sought to improve the public services’ ability to attract and retain employees thereby reducing incentives to emigrate. Methods Using a representative basket of commonly bought goods (including food, entertainment, fuel and utilities), a purchasing power parity (PPP) ratio is an exchange rate between two currencies that equalises the international price of buying that basket. Our study makes comparisons, using such a PPP index, and allows the identification of real differences in salaries for our selected countries (South Africa, United States, United Kingdom, Canada, Australia and Saudi Arabia) for the same HRH professions. If PPP adjusted earnings are indeed different then this indicates an economic incentive to emigrate. Results Salaries of most South African HRH, particularly registered nurses, are dwarfed by their international counterparts (notably United States, Canada and Saudi Arabia), although the OSD has gone some way to reduce that disparity. All selected foreign countries generally offer higher salaries on a PPP adjusted basis. The United Kingdom ($43202) and Australia ($38622), in the category of Medical Officer, are the only two examples where the PPP adjustment brings the salary below what is being offered in South Africa ($50013 post OSD). The PPP adjusted salary differences between registered nurses is very slight for South Africa ($18884 post OSD), Australia

  6. Application specific serial arithmetic arrays

    NASA Technical Reports Server (NTRS)

    Winters, K.; Mathews, D.; Thompson, T.

    1990-01-01

    High performance systolic arrays of serial-parallel multiplier elements may be rapidly constructed for specific applications by applying hardware description language techniques to a library of full-custom CMOS building blocks. Single clock pre-charged circuits have been implemented for these arrays at clock rates in excess of 100 Mhz using economical 2-micron (minimum feature size) CMOS processes, which may be quickly configured for a variety of applications. A number of application-specific arrays are presented, including a 2-D convolver for image processing, an integer polynomial solver, and a finite-field polynomial solver.

  7. IntelliCable Interface Specification

    DTIC Science & Technology

    2016-07-14

    on system operation and is purely information for the user. If it is unused it should be set as 0, which will allow the power manager to display an...IntelliCable vastly reduces the possibility of equipment damage, by providing information tied to each power cable, indicating to the Power Manager ...specific device type is used to further identify the device attached the Power Manager . This field is often extra information or ‘fluff’, used for the

  8. ADANS database specification

    SciTech Connect

    1997-01-16

    The purpose of the Air Mobility Command (AMC) Deployment Analysis System (ADANS) Database Specification (DS) is to describe the database organization and storage allocation and to provide the detailed data model of the physical design and information necessary for the construction of the parts of the database (e.g., tables, indexes, rules, defaults). The DS includes entity relationship diagrams, table and field definitions, reports on other database objects, and a description of the ADANS data dictionary. ADANS is the automated system used by Headquarters AMC and the Tanker Airlift Control Center (TACC) for airlift planning and scheduling of peacetime and contingency operations as well as for deliberate planning. ADANS also supports planning and scheduling of Air Refueling Events by the TACC and the unit-level tanker schedulers. ADANS receives input in the form of movement requirements and air refueling requests. It provides a suite of tools for planners to manipulate these requirements/requests against mobility assets and to develop, analyze, and distribute schedules. Analysis tools are provided for assessing the products of the scheduling subsystems, and editing capabilities support the refinement of schedules. A reporting capability provides formatted screen, print, and/or file outputs of various standard reports. An interface subsystem handles message traffic to and from external systems. The database is an integral part of the functionality summarized above.

  9. Tissue Specific Electrochemical Fingerprinting

    PubMed Central

    Sobrova, Pavlina; Vyslouzilova, Lenka; Stepankova, Olga; Ryvolova, Marketa; Anyz, Jiri; Trnkova, Libuse; Adam, Vojtech; Hubalek, Jaromir; Kizek, Rene

    2012-01-01

    Background Proteomics and metalloproteomics are rapidly developing interdisciplinary fields providing enormous amounts of data to be classified, evaluated and interpreted. Approaches offered by bioinformatics and also by biostatistical data analysis and treatment are therefore of extreme interest. Numerous methods are now available as commercial or open source tools for data processing and modelling ready to support the analysis of various datasets. The analysis of scientific data remains a big challenge, because each new task sets its specific requirements and constraints that call for the design of a targeted data pre-processing approach. Methodology/Principal Findings This study proposes a mathematical approach for evaluating and classifying datasets obtained by electrochemical analysis of metallothionein in rat 9 tissues (brain, heart, kidney, eye, spleen, gonad, blood, liver and femoral muscle). Tissue extracts were heated and then analysed using the differential pulse voltammetry Brdicka reaction. The voltammograms were subsequently processed. Classification models were designed making separate use of two groups of attributes, namely attributes describing local extremes, and derived attributes resulting from the level = 5 wavelet transform. Conclusions/Significance On the basis of our results, we were able to construct a decision tree that makes it possible to distinguish among electrochemical analysis data resulting from measurements of all the considered tissues. In other words, we found a way to classify an unknown rat tissue based on electrochemical analysis of the metallothionein in this tissue. PMID:23185396

  10. Mining Specifications: A Roadmap

    NASA Astrophysics Data System (ADS)

    Zeller, Andreas

    Recent advances in software validation and verification make it possible to widely automate whether a specification is satisfied. This progress is hampered, though, by the persistent difficulty of writing specifications. Are we facing a “specification crisis”? In this paper, I show how to alleviate the burden of writing specifications by reusing and extending specifications as mined from existing software and give an overview on the state of the art in specification mining, its origins, and its potential.

  11. Site Specific Evaluation of Multisensor Capacitance Probes

    USDA-ARS?s Scientific Manuscript database

    Multisensor capacitance probes (MCPs) are widely used for measuring soil water content (SWC) at the field scale. Although manufacturers supply a generic MCP calibration, many researchers recognize that MCPs should be calibrated for specific field conditions. MCPs measurements are typically associa...

  12. Formalisms for user interface specification and design

    NASA Technical Reports Server (NTRS)

    Auernheimer, Brent J.

    1989-01-01

    The application of formal methods to the specification and design of human-computer interfaces is described. A broad outline of human-computer interface problems, a description of the field of cognitive engineering and two relevant research results, the appropriateness of formal specification techniques, and potential NASA application areas are described.

  13. Field Campaign Guidelines (ARM Climate Research Facility)

    SciTech Connect

    Voyles, JW

    2011-01-17

    The purpose of this document is to establish a common set of guidelines for the Atmospheric Radiation Measurement (ARM) Climate Research Facility for planning, executing, and closing out field campaigns. The steps that guide individual field campaigns are described in the Field Campaign Tracking database tool and are tailored to meet the scope of each specific field campaign.

  14. Field Articulation: A Review of the Literature.

    ERIC Educational Resources Information Center

    Korkmaziar, Umran; Zumberg, Marshall F.

    The paper reviews studies of field articulation, that is, dimensions of field dependence-independence in social as well as perceptual domains. Field independence, one's ability to isolate an item from its surroundings, is contrasted with field dependence, manifested in one's difficulties analyzing and focusing on specific aspects of a task. The…

  15. Legal Specific Laserdisks: Not Just a Field of Dreams.

    ERIC Educational Resources Information Center

    Griffith, Cary

    1990-01-01

    Describes available forms of laserdisk technology and discusses the current status of equipment standards and a common retrieval engine. The potential application of laserdisk technology to legal information management is discussed in the areas of research, writing, forms management, law library storage, litigation support, records management,…

  16. Runway Rubber Removal Specification Development: Field Evaluation Procedures Development.

    DTIC Science & Technology

    1984-07-01

    Administration, Hampton, Virginia, 1983. 7. Moore, 0. F., The Friction of Pneumatic Tyres , Elsevier Scientific Publishing Company, New York, New York, 1975...The Friction of Pneumatic Tyres , Elsevier Scientific Publishing Company, New York, New York, 1975. 8. Kummer, H. W., Unified Theory of Rubber and Tire...Ref. 10) on pneumatic tire hydroplaning, states there are three types of hydroplaning, viz., dynamic, viscous, and reverted tire rubber hydroplaning

  17. Arun field

    SciTech Connect

    Jordan, C.F. Jr.; Abdullah, M.

    1988-01-01

    The Arun field is a giant gas-condensate field operated by Mobil and Pertamina with over 20,000 acres of closure at the top of the Arun reservoir. A middle-shelf patch reef complex of early to middle Miocene age is the producing facies at the Arun field. About 1,100 ft of porous limestones, encased in shales, create a stratigraphic trap for overpressure hydrocarbons. Three main carbonate lithologies were encountered during the examination of over 4,300 ft of core; (1) a reef facies consisting of vuggy, coral encrusting, red-algal boundstones, (2) a near-reef facies consisting of foraminiferal, mixed-skeletal packstones with gravel-size coral fragments, and (3) an interreef lagoonal facies consisting of benthonic-foram packstones. Twenty-two species of corals have been identified from Arun reef facies; major reef-forming coals, listed in order of decreasing abundance, are Porites cf P. Lutes, Cyphastrea microphthalma, Astreopora myriophthalma, Styloconiella gunetheri, Porites solida, and Acropora ssp. The Arun reef is comprised of limestones (with minor amounts of dolomite). No shale beds occur in the sequence, and all carbonate facies are in communication. A pervasive microporosity, occurring throughout the Arun Limestone, results from meteoric alteration of original carbonate mud to form a microrhombic porosity that accounts for about three-fourths of the field's total porosity.

  18. Magnetic field reconnection

    NASA Astrophysics Data System (ADS)

    Axford, W. I.

    The fundamental principles of particle acceleration by magnetic reconnection in cosmic plasmas are reviewed. The history of reconnection models is traced, and consideration is given to the Kelvin-Helmholtz theorem, the frozen-field theorem, the application of the Kelvin-Helmholtz theorem to a collisionless plasma, solutions to specific reconnection problems, and configurational instability. Diagrams and graphs are provided, and the objections raised by critics of the reconnection theory and/or its astrophysical applications are discussed.

  19. Urine specific gravity test

    MedlinePlus

    ... medlineplus.gov/ency/article/003587.htm Urine specific gravity test To use the sharing features on this page, please enable JavaScript. Urine specific gravity is a laboratory test that shows the concentration ...

  20. Swimming in external fields

    NASA Astrophysics Data System (ADS)

    Stark, Holger

    2016-11-01

    Microswimmers move autonomously but are subject to external fields, which influence their swimming path and their collective dynamics. With three concrete examples we illustrate swimming in external fields and explain the methodology to treat it. First, an active Brownian particle shows a conventional sedimentation profile in a gravitational field but with increased sedimentation length and some polar order along the vertical. Bottom-heavy swimmers are able to invert the sedimentation profile. Second, active Brownian particles interacting by hydrodynamic flow fields in a three-dimensional harmonic trap can spontaneously break the isotropic symmetry. They develop polar order, which one can describe by mean-field theory reminiscent to Weiss theory of ferromagnetism, and thereby pump fluid. Third, a single microswimmer shows interesting non-linear dynamics in Poiseuille flow including swinging and tumbling trajectories. For pushers, hydrodynamic interactions with bounding surfaces stabilize either straight swimming against the flow or tumbling close to the channel wall, while pushers always move on a swinging trajectory with a specific amplitude as limit cycle.

  1. On field line resonances of hydromagnetic Alfven waves in dipole magnetic field

    SciTech Connect

    Chen, Liu; Cowley, S.C.

    1989-07-01

    Using the dipole magnetic field model, we have developed the theory of field line resonances of hydromagnetic Alfven waves in general magnetic field geometries. In this model, the Alfven speed thus varies both perpendicular and parallel to the magnetic field. Specifically, it is found that field line resonances do persist in the dipole model. The corresponding singular solutions near the resonant field lines as well as the natural definition of standing shear Alfven eigenfunctions have also been systematically derived. 11 refs.

  2. Gauge fields and inflation

    NASA Astrophysics Data System (ADS)

    Maleknejad, A.; Sheikh-Jabbari, M. M.; Soda, J.

    2013-07-01

    The isotropy and homogeneity of the cosmic microwave background (CMB) favors “scalar driven” early Universe inflationary models. However, gauge fields and other non-scalar fields are far more common at all energy scales, in particular at high energies seemingly relevant to inflation models. Hence, in this review we consider the role and consequences, theoretical and observational, that gauge fields can have during the inflationary era. Gauge fields may be turned on in the background during inflation, or may become relevant at the level of cosmic perturbations. There have been two main classes of models with gauge fields in the background, models which show violation of the cosmic no-hair theorem and those which lead to isotropic FLRW cosmology, respecting the cosmic no-hair theorem. Models in which gauge fields are only turned on at the cosmic perturbation level, may source primordial magnetic fields. We also review specific observational features of these models on the CMB and/or the primordial cosmic magnetic fields. Our discussions will be mainly focused on the inflation period, with only a brief discussion on the post inflationary (p)reheating era. Large field models: The initial value of the inflaton field is large, generically super-Planckian, and it rolls slowly down toward the potential minimum at smaller φ values. For instance, chaotic inflation is one of the representative models of this class. The typical potential of large-field models has a monomial form as V(φ)=V0φn. A simple analysis using the dynamical equations reveals that for number of e-folds Ne larger than 60, we require super-Planckian initial field values,5φ0>3M. For these models typically ɛ˜η˜Ne-1. Small field models: Inflaton field is initially small and slowly evolves toward the potential minimum at larger φ values. The small field models are characterized by the following potential V(φ)=V0(1-(), which corresponds to a Taylor expansion about the origin, but more realistic

  3. Specific heat revisited

    NASA Astrophysics Data System (ADS)

    Pizarro, C. A.; Condat, C. A.; Lamberti, P. W.; Prato, D. P.

    1996-06-01

    The correlation between potential shape and specific heat is generally absent from textbook discussions. We present a detailed analysis of the specific heat contribution due to independent particles subject to one-dimensional classical and quantum model potentials. For the classical models, we use phase space concepts to develop a clear physical interpretation of the temperature dependence of the specific heat. For the quantum models, we make the interpretation in terms of the differences in quantum levels.

  4. 78 FR 33633 - Human Exposure to Radiofrequency Electromagnetic Fields

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-04

    ... to Radiofrequency Electromagnetic Fields; Reassessment of Exposure to Radiofrequency Electromagnetic..., and 95 Human Exposure to Radiofrequency Electromagnetic Fields AGENCY: Federal Communications... electromagnetic fields. More specifically, the Commission clarifies evaluation procedures and references...

  5. [Specific dermatoses of pregnancy].

    PubMed

    Teixeira, Vera; Coutinho, Inês; Gameiro, Rita; Vieira, Ricardo; Gonçalo, Margarida

    2013-01-01

    During pregnancy immunological, metabolic, hormonal and vascular changes occur, and can cause specific skin diseases. The specific dermatoses of pregnancy have undergone numerous changes in nomenclature and classification, partly due to advances in the knowledge of the pathogenesis of these skin diseases. Currently the following diseases are considered specific dermatoses of pregnancy: pemphigoid gestations, polymorphic eruption of pregnancy, intrahepatic cholestasis of pregnancy and atopic eruption of pregnancy. Timely diagnosis and specific and safe treatment are essential to prevent complications which, although rare, may be associated with significant maternal-fetal comorbidity.

  6. NMR at very low fields.

    PubMed

    Trahms, Lutz; Burghoff, Martin

    2010-10-01

    Although nuclear magnetic resonance in low fields around or below the Earth's magnetic field is almost as old as nuclear magnetic resonance itself, the recent years have experienced a revival of this technique that is opposed to the common trend towards higher and higher fields. The background of this development is the expectation that the low-field domain may open a new window for the study of molecular structure and dynamics. Here, we will give an overview on the specific features in the low-field domain, both from the technical and from the physical point of view. In addition, we present a short passage on the option of magnetic resonance imaging in fields of the micro-Tesla range.

  7. Improved technical specifications

    SciTech Connect

    Hoffman, D.R.

    1994-12-31

    Improved technical specifications for nuclear power plants are outlined. The objectives of this work are to improve safety, provide a clearer understanding of safety significance, and ease NRC and industry administrative burdens. Line item improvements, bases, and implementation of the specifications are discussed.

  8. Prototype Facility Educational Specifications.

    ERIC Educational Resources Information Center

    Idaho State Div. of Professional-Technical Education, Boise.

    This document presents prototypical educational specifications to guide the building and renovation of Idaho vocational schools so they can help communities meet the advanced, professional-technical programs of the future. The specifications start with points to consider when determining school site suitability. The document then sets forth…

  9. Statistical and Economic Techniques for Site-specific Nematode Management.

    PubMed

    Liu, Zheng; Griffin, Terry; Kirkpatrick, Terrence L

    2014-03-01

    Recent advances in precision agriculture technologies and spatial statistics allow realistic, site-specific estimation of nematode damage to field crops and provide a platform for the site-specific delivery of nematicides within individual fields. This paper reviews the spatial statistical techniques that model correlations among neighboring observations and develop a spatial economic analysis to determine the potential of site-specific nematicide application. The spatial econometric methodology applied in the context of site-specific crop yield response contributes to closing the gap between data analysis and realistic site-specific nematicide recommendations and helps to provide a practical method of site-specifically controlling nematodes.

  10. Statistical and Economic Techniques for Site-specific Nematode Management

    PubMed Central

    Liu, Zheng; Griffin, Terry; Kirkpatrick, Terrence L.

    2014-01-01

    Recent advances in precision agriculture technologies and spatial statistics allow realistic, site-specific estimation of nematode damage to field crops and provide a platform for the site-specific delivery of nematicides within individual fields. This paper reviews the spatial statistical techniques that model correlations among neighboring observations and develop a spatial economic analysis to determine the potential of site-specific nematicide application. The spatial econometric methodology applied in the context of site-specific crop yield response contributes to closing the gap between data analysis and realistic site-specific nematicide recommendations and helps to provide a practical method of site-specifically controlling nematodes. PMID:24643451

  11. Microbial field pilot study

    SciTech Connect

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Coates, J.D.; Chisholm, J.L.

    1993-05-01

    A multi-well microbially enhanced oil recovery field pilot has been performed in the Southeast Vassar Vertz Sand Unit in Payne County, Oklahoma. The primary emphasis of the experiment was preferential plugging of high permeability zones for the purpose of improving waterflood sweep efficiency. Studies were performed to determine reservoir chemistry, ecology, and indigenous bacteria populations. Growth experiments were used to select a nutrient system compatible with the reservoir that encouraged growth of a group of indigenous nitrate-using bacteria and inhibit growth of sulfate-reducing bacteria. A specific field pilot area behind an active line drive waterflood was selected. Surface facilities were designed and installed. Injection protocols of bulk nutrient materials were prepared to facilitate uniform distribution of nutrients within the pilot area. By the end of December, 1991, 82.5 tons (75.0 tonnes) of nutrients had been injected in the field. A tracer test identified significant heterogeneity in the SEVVSU and made it necessary to monitor additional production wells in the field. The tracer tests and changes in production behavior indicate the additional production wells monitored during the field trial were also affected. Eighty two and one half barrels (13.1 m[sup 3]) of tertiary oil have been recovered. Microbial activity has increased CO[sub 2] content as indicated by increased alkalinity. A temporary rise in sulfide concentration was experienced. These indicate an active microbial community was generated in the field by the nutrient injection. Pilot area interwell pressure interference test results showed that significant permeability reduction occurred. The interwell permeabilities in the pilot area between the injector and the three pilot production wells were made more uniform which indicates a successful preferential plugging enhanced oil recovery project.

  12. 7 CFR 1755.3 - Field trials.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Field trials. 1755.3 Section 1755.3 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.3 Field... modifications that its suitability cannot be determined based on laboratory data and/or field experience,...

  13. 24 CFR 3285.601 - Field assembly.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Field assembly. 3285.601 Section... § 3285.601 Field assembly. Home manufacturers must provide specific installation instructions for the proper field assembly of manufacturer-supplied and shipped loose ducts, plumbing, and fuel supply...

  14. 24 CFR 3285.601 - Field assembly.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Field assembly. 3285.601 Section... § 3285.601 Field assembly. Home manufacturers must provide specific installation instructions for the proper field assembly of manufacturer-supplied and shipped loose ducts, plumbing, and fuel supply...

  15. 7 CFR 1755.3 - Field trials.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Field trials. 1755.3 Section 1755.3 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.3 Field... modifications that its suitability cannot be determined based on laboratory data and/or field experience,...

  16. 24 CFR 3285.601 - Field assembly.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Field assembly. 3285.601 Section... § 3285.601 Field assembly. Home manufacturers must provide specific installation instructions for the proper field assembly of manufacturer-supplied and shipped loose ducts, plumbing, and fuel supply...

  17. 7 CFR 1755.3 - Field trials.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Field trials. 1755.3 Section 1755.3 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.3 Field... modifications that its suitability cannot be determined based on laboratory data and/or field experience,...

  18. 24 CFR 3285.601 - Field assembly.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Field assembly. 3285.601 Section... § 3285.601 Field assembly. Home manufacturers must provide specific installation instructions for the proper field assembly of manufacturer-supplied and shipped loose ducts, plumbing, and fuel supply...

  19. 7 CFR 1755.3 - Field trials.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 11 2014-01-01 2014-01-01 false Field trials. 1755.3 Section 1755.3 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.3 Field... modifications that its suitability cannot be determined based on laboratory data and/or field experience,...

  20. GMSEC Interface Specification Document 2016 March

    NASA Technical Reports Server (NTRS)

    Handy, Matthew

    2016-01-01

    The GMSEC Interface Specification Document contains the standard set of defined messages. Each GMSEC standard message contains a GMSEC Information Bus Header section and a Message Contents section. Each message section identifies required fields, optional fields, data type and recommended use of the fields. Additionally, this document includes the message subjects associated with the standard messages. The system design of the operations center should ensure the components that are selected use both the API and the defined standard messages in order to achieve full interoperability from component to component.

  1. Quantum field tomography

    NASA Astrophysics Data System (ADS)

    Steffens, A.; Riofrío, C. A.; Hübener, R.; Eisert, J.

    2014-12-01

    We introduce the concept of quantum field tomography, the efficient and reliable reconstruction of unknown quantum fields based on data of correlation functions. At the basis of the analysis is the concept of continuous matrix product states (cMPS), a complete set of variational states grasping states in one-dimensional quantum field theory. We innovate a practical method, making use of and developing tools in estimation theory used in the context of compressed sensing such as Prony methods and matrix pencils, allowing us to faithfully reconstruct quantum field states based on low-order correlation functions. In the absence of a phase reference, we highlight how specific higher order correlation functions can still be predicted. We exemplify the functioning of the approach by reconstructing randomized cMPS from their correlation data and study the robustness of the reconstruction for different noise models. Furthermore, we apply the method to data generated by simulations based on cMPS and using the time-dependent variational principle. The presented approach is expected to open up a new window into experimentally studying continuous quantum systems, such as those encountered in experiments with ultra-cold atoms on top of atom chips. By virtue of the analogy with the input-output formalism in quantum optics, it also allows for studying open quantum systems.

  2. Vector fields in cosmology

    NASA Astrophysics Data System (ADS)

    Davydov, E. A.

    2012-06-01

    Vector fields can arise in the cosmological context in different ways, and we discuss both abelian and nonabelian sector. In the abelian sector vector fields of the geometrical origin (from dimensional reduction and Einstein-Eddington modification of gravity) can provide a very non-trivial dynamics, which can be expressed in terms of the effective dilaton-scalar gravity with the specific potential. In the non-abelian sector we investigate the Yang-Mills SU(2) theory which admits isotropic and homogeneous configuration. Provided the non-linear dependence of the lagrangian on the invariant FμνF~μν, one can obtain the inflationary regime with the exponential growth of the scale factor. The effective amplitudes of the `electric' and `magnetic' components behave like slowly varying scalars at this regime, what allows the consideration of some realistic models with non-linear terms in the Yang-Mills lagrangian.

  3. Field dependence and distraction revisited.

    PubMed

    Blowers, G H

    1976-02-01

    An attempt is made to replicate a former study of the relationship of field dependence as measured by rod-and-frame errors to distraction in an RT paradigm. For two groups of Ss (n = 14) who differed specifically in their dependence upon the tilted frame and were classified as frame-dependent and frame-independent, no relationship of frame (or field) dependence to susceptibility to distraction was found.

  4. Issues Specific to Women

    MedlinePlus

    ... War Specific to Women Types of Trauma War Terrorism Violence and Abuse Disasters Is it PTSD? Treatment ... Overview Types of Trauma Trauma Basics Disaster and Terrorism Military Trauma Violence & other Trauma Assessment Assessment Overview ...

  5. VOST charcoal specification study

    SciTech Connect

    Foster, A.L.; Bursey, J.T.

    1995-07-01

    The volatile organic sampling train, SW-846 Method 0030, (VOST) is currently one of the leading methodology`s available for the sampling and analysis of volatile organic hazardous compounds from stationary sources at very low levels. The method does not identify a specific equivalent sorbent, nor the performance specifications which would allow determination of an equivalent. Lot 104 petroleum-based charcoal is no longer commercially available. Laboratories are presently using a wide range of substitutes with varying performance from batch to batch of charcoal. To provide performance specifications and identify a replacement for SKC Lot 104 charcoal, a VOST charcoal specification study was initiated. Performance, cost, ease of handling, and plentiful supply make Anasorb 747 a good choice for replacement of SKX Lot 104.

  6. Phobia - simple/specific

    MedlinePlus

    ... enable JavaScript. A phobia is an ongoing intense fear or anxiety of a certain object, animal, activity, ... panic attack when exposed to the object of fear. Specific phobias are a common mental disorder. Common ...

  7. Languages for Specific Purposes.

    ERIC Educational Resources Information Center

    Swales, John M.

    2000-01-01

    Focuses on languages for specific purposes, providing a brief historical perspective, examining it as a profession, discipline, or neither; its role in science and law; language for business purposes; and the position of English worldwide. (Author/VWL)

  8. TWRSview system requirements specification

    SciTech Connect

    Caldwell, J.A.; Lee, A.K.

    1995-12-01

    This document provides the system requirements specification for the TWRSview software system. The TWRSview software system is being developed to integrate electronic data supporting the development of the TWRS technical baseline

  9. Harmonization of Biodiesel Specifications

    SciTech Connect

    Alleman, T. L.

    2008-02-01

    Worldwide biodiesel production has grown dramatically over the last several years. Biodiesel standards vary across countries and regions, and there is a call for harmonization. For harmonization to become a reality, standards have to be adapted to cover all feedstocks. Additionally, all feedstocks cannot meet all specifications, so harmonization will require standards to either tighten or relax. For harmonization to succeed, the biodiesel market must be expanded with the alignment of test methods and specification limits, not contracted.

  10. Specificity Controls for Immunocytochemistry

    PubMed Central

    Holmseth, Silvia; Zhou, Yun; Follin-Arbelet, Virginie V.; Lehre, Knut Petter; Bergles, Dwight E.

    2012-01-01

    The biomedical research community relies directly or indirectly on immunocytochemical data. Unfortunately, validation of labeling specificity is difficult. A common specificity test is the preadsorption test. This test was intended for testing crude antisera but is now frequently used to validate monoclonal and affinity purified polyclonal antibodies. Here, the authors assess the power of this test. Nine affinity purified antibodies to different epitopes on 3 proteins (EAAT3, slc1a1; EAAT2, slc1a2; BGT1, slc6a12) were tested on samples (tissue sections and Western blots with or without fixation). The selected antibodies displayed some degree of cross-reactivity as defined by labeling of samples from knockout mice. The authors show that antigen preadsorption blocked all labeling of both wild-type and knockout samples, implying that preadsorption also blocked binding to cross-reactive epitopes. They show how this can give an illusion of specificity and illustrate sensitivity-specificity relationships, the importance of good negative controls, that fixation can create new epitopes, and that cross-reacting epitopes present in sections may not be present on Western blots and vice versa. In conclusion, they argue against uncritical use of the preadsorption test and, in doing so, address a number of other issues related to immunocytochemistry specificity testing. PMID:22215633

  11. 7 CFR 58.140 - Field service.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., GENERAL SPECIFICATIONS FOR APPROVED PLANTS AND STANDARDS FOR GRADES OF DAIRY PRODUCTS 1 General Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw Milk § 58.140 Field service. A representative of the plant shall arrange to promptly visit the farm...

  12. 7 CFR 58.140 - Field service.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., GENERAL SPECIFICATIONS FOR APPROVED PLANTS AND STANDARDS FOR GRADES OF DAIRY PRODUCTS 1 General Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw Milk § 58.140 Field service. A representative of the plant shall arrange to promptly visit the farm...

  13. 7 CFR 58.140 - Field service.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., GENERAL SPECIFICATIONS FOR APPROVED PLANTS AND STANDARDS FOR GRADES OF DAIRY PRODUCTS 1 General Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw Milk § 58.140 Field service. A representative of the plant shall arrange to promptly visit the farm...

  14. Synaptic Effects of Electric Fields

    NASA Astrophysics Data System (ADS)

    Rahman, Asif

    Learning and sensory processing in the brain relies on the effective transmission of information across synapses. The strength and efficacy of synaptic transmission is modifiable through training and can be modulated with noninvasive electrical brain stimulation. Transcranial electrical stimulation (TES), specifically, induces weak intensity and spatially diffuse electric fields in the brain. Despite being weak, electric fields modulate spiking probability and the efficacy of synaptic transmission. These effects critically depend on the direction of the electric field relative to the orientation of the neuron and on the level of endogenous synaptic activity. TES has been used to modulate a wide range of neuropsychiatric indications, for various rehabilitation applications, and cognitive performance in diverse tasks. How can a weak and diffuse electric field, which simultaneously polarizes neurons across the brain, have precise changes in brain function? Designing therapies to maximize desired outcomes and minimize undesired effects presents a challenging problem. A series of experiments and computational models are used to define the anatomical and functional factors leading to specificity of TES. Anatomical specificity derives from guiding current to targeted brain structures and taking advantage of the direction-sensitivity of neurons with respect to the electric field. Functional specificity originates from preferential modulation of neuronal networks that are already active. Diffuse electric fields may recruit connected brain networks involved in a training task and promote plasticity along active synaptic pathways. In vitro, electric fields boost endogenous synaptic plasticity and raise the ceiling for synaptic learning with repeated stimulation sessions. Synapses undergoing strong plasticity are preferentially modulated over weak synapses. Therefore, active circuits that are involved in a task could be more susceptible to stimulation than inactive circuits

  15. Pulse-shape discrimination scintillators for homeland security applications

    NASA Astrophysics Data System (ADS)

    Ellis, Mark E.; Duroe, Kirk; Kendall, Paul A.

    2016-09-01

    An extensive programme of research has been conducted for scintillation liquids and plastics capable of neutron-gamma discrimination for deployment in future passive and active Homeland Security systems to provide protection against radiological and nuclear threats. The more established detection materials such as EJ-301 and EJ-309 are compared with novel materials such as EJ-299-33 and p-terphenyl. This research also explores the benefits that can be gained from improvements in the analogue-to-digital sampling rate and sample bit resolution. Results are presented on the Pulse Shape Discrimination performance of various detector and data acquisition combinations and how optimum configurations from these studies have been developed into field-ready detector arrays. Early results from application-specific experimental configurations of multi-element detector arrays are presented.

  16. USA Track & Field Coaching Manual. USA Track & Field.

    ERIC Educational Resources Information Center

    USA Track and Field, Inc., Indianapolis, IN.

    This book presents comprehensive, ready-to-apply information from 33 world-class coaches and experts about major track and field events for high school and college coaches. The volume features proven predictive testing procedures; detailed event-specific technique instruction; carefully crafted training programs; and preparation and performance…

  17. USA Track & Field Coaching Manual. USA Track & Field.

    ERIC Educational Resources Information Center

    USA Track and Field, Inc., Indianapolis, IN.

    This book presents comprehensive, ready-to-apply information from 33 world-class coaches and experts about major track and field events for high school and college coaches. The volume features proven predictive testing procedures; detailed event-specific technique instruction; carefully crafted training programs; and preparation and performance…

  18. Lidar base specification

    USGS Publications Warehouse

    Heidemann, Hans Karl.

    2012-01-01

    In late 2009, a $14.3 million allocation from the “American Recovery and Reinvestment Act” for new light detection and ranging (lidar) elevation data prompted the U.S. Geological Survey (USGS) National Geospatial Program (NGP) to develop a common base specification for all lidar data acquired for The National Map. Released as a draft in 2010 and formally published in 2012, the USGS–NGP “Lidar Base Specification Version 1.0” (now Lidar Base Specification) was quickly embraced as the foundation for numerous state, county, and foreign country lidar specifications. Prompted by a growing appreciation for the wide applicability and inherent value of lidar, a USGS-led consortium of Federal agencies commissioned a National Enhanced Elevation Assessment (NEEA) study in 2010 to quantify the costs and benefits of a national lidar program. A 2012 NEEA report documented a substantial return on such an investment, defined five Quality Levels (QL) for elevation data, and recommended an 8-year collection cycle of Quality Level 2 (QL2) lidar data as the optimum balance of benefit and affordability. In response to the study, the USGS–NGP established the 3D Elevation Program (3DEP) in 2013 as the interagency vehicle through which the NEEA recommendations could be realized. Lidar is a fast evolving technology, and much has changed in the industry since the final draft of the “Lidar Base Specification Version 1.0” was written. Lidar data have improved in accuracy and spatial resolution, geospatial accuracy standards have been revised by the American Society for Photogrammetry and Remote Sensing (ASPRS), industry standard file formats have been expanded, additional applications for lidar have become accepted, and the need for interoperable data across collections has been realized. This revision to the “Lidar Base Specification Version 1.0” publication addresses those changes and provides continued guidance towards a nationally consistent lidar dataset.

  19. Mask cost and specification

    NASA Astrophysics Data System (ADS)

    Watanabe, Hisashi; Higashikawa, Iwao

    2003-12-01

    At the panel discussion of Photomask Japan 2003, we discussed about Mask cost and specification. The topics are (1) Mask price trend and its impact, (2) How to reduce the mask costs; solutions from a mask shop, mask writing tool and mask inspection tool 3) Partnering mask suppliers with mask users; reasonable mask specification and OPC strategies. The choice of DUV laser writer instead of e-beam writer is one solution for reduction of mask cost. The continuous improvement of e-beam writer and resist sensitivity for high throughput is another solution. The partnership between designer, EDA vender, mask maker and wafer lithographer becomes more important.

  20. Automated Library System Specifications.

    DTIC Science & Technology

    1986-06-01

    AD-A78 95 AUTOMATED LIBRARY SYSTEM SPECIFICATIONS(U) ARMY LIBRARY /i MANAGEMENT OFFICE ALEXANDRIA VA ASSISTANT CHIEF OF STAFF FOR INFORMATION... MANAGEMENT M B BONNETT JUN 86 UNCLASSIFIED F/G 9/2 NLEElIIhllEEEEE IllEEEEEllllEI .1lm lliml * ~I fI.L25 MI, [OCM RL,;OCLUTO fl. ’N k~ AUTOMATED LIBRARY...SYSTEM SPECIFICATIONS .,I Prepared by Mary B. Bonnett ARMY LIBRARY MANAGEMENT OFFICE OFFICE OF THE ASSISTANT CHIEF OF STAFF FOR INFORMATION MANAGEMENT Lij