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Sample records for dynamic range bf3

  1. High pressure BF3 proportional counter

    International Nuclear Information System (INIS)

    Mihara, Masaru; Gotoh, Eiichiro; Kodama, Masahiro

    1978-01-01

    Plateau and pulse characteristics of high pressure BF 3 proportional counter were investigated in terms of counter geometry and gas pressure, in order to develop a small-sized and high-sensitive one. Description is given of the construction of improved gas filling equipment with filling procedure. A tentative brass counter, 67 mm in cathode diameter, 40 micron in anode diameter, filled to 1.2 kg/cm 2 revealed characteristics of 150 volts plateau range, the slope of which being 3% per 100 volts at the operation voltage of around 3.3 kV, and 103% full width at half-maximum in the pulse height distribution. (auth.)

  2. MCNP to study the BF3 detection efficiency

    International Nuclear Information System (INIS)

    Castro, Vinicius A.; Cavalieri, Tassio A.; Siqueira, Paulo T.D.; Fedorenko, Giuliana G.; Coelho, Paulo R.P.; Madi Filho, Tufic

    2011-01-01

    One of the main parameters to monitor on the employment of the Boron Neutron Capture Therapy (BNCT) is the thermal neutron flux. It can be performed by different techniques such as the activation analysis and the detection by a Boron Trifluoride detector (BF 3 ). BF 3 detector is a real time neutron flux detector which retrieves results in real time. It is however necessary to study the efficiency of the BF 3 detectors when they are exposed to fields of different neutron energy spectra. BF 3 is known to have high efficiency for thermal neutrons (with energy up to 0.5 eV) due the presence of 10 B atoms in the detector. However, one must also understand how this detector interacts with other neutron energy ranges (epithermal and fast). This work shows the experiment and a set of associated simulations carried out in order to evaluate the BF 3 detector efficiency dependence on neutron energy spectra. A set of experiments was conducted in which a BF 3 detector was submitted to different mixed fields (field containing gamma rays and neutrons). These fields were generated by the interposition of paraffin layers with distinct thicknesses between the Am-Be source and the BF 3 detector. The BF 3 detector responses were recorded according to the number of paraffin planes used. MCNP simulations were also performed to study the detector responses on such experimental conditions. It has been possible to achieve the intended goal of evaluating the BF 3 detector response to different mixed irradiation fields. (author)

  3. Development and performance research of array BF3 detector

    International Nuclear Information System (INIS)

    Tang Zhangkui; Tang Zhengyuan; Xu Rongkun; Liu Hangang; Li Bojun; Hu Mengchun; Fan Juan

    2005-01-01

    The array BF 3 detector was designed and developed for measuring DT pulse neutron yields. The detection sensitivity of detector was calibrated by a series of neutron measurement on the accelerator. The relative measuring data and its uncertainty from array BF 3 detection were obtained and compared with that from other measuring methods. Experiment data verifies the reliability of array BF 3 detector to be used for measuring DT pulse neutron. (author)

  4. BF3-doped polyaniline: A novel conducting polymer

    Indian Academy of Sciences (India)

    A detailed procedure for the synthesis of PANI and doping with BF3 has been previously reported [2]. The sample was characterized for complete doping us- ing routine spectroscopic techniques, like UV–visible absorption, FTIR and 11B magic-angle-spinning (MAS) NMR spectroscopy. For the four-probe conductivity. 135 ...

  5. Effect of adding Ar gas on the pulse height distribution of BF3-filled ...

    Indian Academy of Sciences (India)

    Abstract. Boron trifluoride (BF3) proportional counters are used as detectors for ther- mal neutrons. They are characterized by high neutron sensitivity and good gamma dis- criminating properties. Most practical BF3 counters are filled with pure boron trifluoride gas enriched up to 96% 10B. But BF3 is not an ideal proportional ...

  6. Effect of adding Ar gas on the pulse height distribution of BF3-filled ...

    Indian Academy of Sciences (India)

    Boron trifluoride (BF3) proportional counters are used as detectors for thermal neutrons. They are characterized by high neutron sensitivity and good gamma discriminating properties. Most practical BF3 counters are filled with pure boron trifluoride gas enriched up to 96% 10B. But BF3 is not an ideal proportional counter ...

  7. Xylanase Activity of Streptomyces violascences BF 3.10 on Xylan Corncobs and its Xylooligosaccharide Production

    Directory of Open Access Journals (Sweden)

    W. Salupi

    2015-04-01

    Full Text Available Corn is one of the important carbohydrate sources in Indonesia that is mainly used for food and industrial materials. In addition, the byproducts of corn, such as corncobs, have been reported as xylan-containing materials that can be utilized as substrate in xylooligosaccharides (XOS production. XOS are natural prebiotic fibers that can enhance the performance of animal’s digestive system. The main objective of this study was to exploit xylan from corncobs to produce XOS. The research consisted of extraction and production of xylan from corncobs and the synthesis of XOS from corncob-produced xylan. The corncob and Streptomyces violascens BF 3.10 xylanase is a collection of PPSHB IPB Laboratory. Corncobs xylan extracted by using alkaline method and reducting sugar was analyzed by dinitrosalicylic acid method. The xylan extraction from corncobs could produce 7.93% (w/w of xylan. The activity of S. violascens BF 3.10 xylanase on the substrate of concorb-produced xylan was 6.4 U/mL at the optimum temperature of 60 °C in 50 mM phosphate buffer with pH 5.5. The thin layer chromatography analysis indicated that 1% (w/v corn-cob xylan could produce XOS with degree of polymerization (DP 3.92. XOS, with DP ranging from 2-4, could be used as a livestock feed mixture to stimulate the growth of normal microbes in the gastrointestinal tract of livestock.

  8. Pulsed jet Fourier transform microwave spectroscopy of the BF3-CO complex

    Science.gov (United States)

    Feng, Gang; Gou, Qian; Evangelisti, Luca; Grabow, Jens-Uwe; Caminati, Walther

    2017-05-01

    The rotational spectrum of the van der Waals complex between BF3 and CO was studied using a pulse jet Fourier transform microwave spectrometer, which renewed the electric resonance spectroscopic measurements by Klemperer et al. [J. Am. Chem. Soc. 100 (1978) 8074]. The spectral measurements have been considerably extended and the newly assigned rotational spectrum of the isotopologue BF3-C18O allowed for a precise structural analysis confirming the effective collinearity of the atoms B, C and O in the complex.

  9. Verification of Gamma-ray Sensitivity for BF3 Neutron Detection System

    International Nuclear Information System (INIS)

    Choi, Yu Sun; Cho, Jin Bok; Lyou, Seok Jean

    2016-01-01

    The BF3(Boron Tri-Fluorides) gas filled neutron detector(hereafter BF3 Detector) is commonly used for nuclear reactor’s startup channel due to its relatively high neutron efficiency and good discrimination against gamma-ray backgrounds. In order to measure how much this gamma-ray will affect on BF3 neutron detector performance in view of gamma noise discrimination, Multi-Channel Analyzer(MCA) is utilized for spectrum based signal analysis. The pre-test of BF3 Detector should be performed in an area where the ionization does not exceed 2.5 micro Gy/Hr(Ref.1). In this paper, the discrimination level (Voltage Unit) is verified by experimentally measurement if that discrimination level is acceptable within the criteria or not before installation. The maximum discrimination level, so called LLD, is determined by experimentally measurement. This BF3 Detector (LND20372) is insensitive under 540 micro Gy/Hr of gamma ray and 0.3V of LLD could cut off a background and gamma induced signal in a laboratory. MCA could be a convenient tool for spectrum analysis of signals that induced from gamma ray and a time saving tool rather than oscilloscope investigation due to its function to integrate all input signals at a sudden duration

  10. High dynamic range ultrasound imaging.

    Science.gov (United States)

    Degirmenci, Alperen; Perrin, Douglas P; Howe, Robert D

    2018-03-16

    High dynamic range (HDR) imaging is a popular computational photography technique that has found its way into every modern smartphone and camera. In HDR imaging, images acquired at different exposures are combined to increase the luminance range of the final image, thereby extending the limited dynamic range of the camera. Ultrasound imaging suffers from limited dynamic range as well; at higher power levels, the hyperechogenic tissue is overexposed, whereas at lower power levels, hypoechogenic tissue details are not visible. In this work, we apply HDR techniques to ultrasound imaging, where we combine ultrasound images acquired at different power levels to improve the level of detail visible in the final image. Ultrasound images of ex vivo and in vivo tissue are acquired at different acoustic power levels and then combined to generate HDR ultrasound (HDR-US) images. The performance of five tone mapping operators is quantitatively evaluated using a similarity metric to determine the most suitable mapping for HDR-US imaging. The ex vivo and in vivo results demonstrated that HDR-US imaging enables visualizing both hyper- and hypoechogenic tissue at once in a single image. The Durand tone mapping operator preserved the most amount of detail across the dynamic range. Our results strongly suggest that HDR-US imaging can improve the utility of ultrasound in image-based diagnosis and procedure guidance.

  11. BF3/nano-γ-Al2O3 Promoted Knoevenagel Condensation at Room Temperature

    Directory of Open Access Journals (Sweden)

    B. F. Mirjalili

    2015-10-01

    Full Text Available The Knoevenagel condensation of aromatic aldehydes with barbituric acid, dimedone and malononitrile occurred in the presence of BF3/nano-γ-Al2O3 at room temperature in ethanol. This catalyst is characterized by powder X-ray diffraction (XRD, fourier transform infrared spectroscopy (FT-IR, thermal gravimetric analysis (TGA, field emission scanning electron microscopy (FESEM and energy-dispersive X-ray spectroscopy (EDS.

  12. An R-matrix study of electron induced processes in BF3 plasma

    Science.gov (United States)

    Gupta, Dhanoj; Chakrabarti, Kalyan; Yoon, Jung-Sik; Song, Mi-Young

    2017-12-01

    An R-matrix formalism is used to study electron collision with the BF3 molecule using Quantemol-N, a computational system for electron molecule collisions which uses the molecular R-matrix method. Several target models are tested for BF3 in its equilibrium geometry, and the results are presented for the best model. Scattering calculations are then performed to yield resonance parameters, elastic, differential, excitation, and momentum transfer cross sections. The results for all the cross sections are compared with the experimental and theoretical data, and a good agreement is obtained. The resonances have been detected at 3.79 and 13.58 eV, with the ionization threshold being 15.7 eV. We have also estimated the absolute dissociative electron attachment (DEA) cross section for the F- ion production from BF3, which is a maiden attempt. The peak of the DEA is at around 13.5 eV, which is well supported by the resonance detected at 13.58 eV. The cross sections reported here find a variety of applications in the plasma technology.

  13. Dynamic range majority data structures

    DEFF Research Database (Denmark)

    Elmasry, Amr Ahmed Abd Elmoneim; He, Meng; Munro, J. Ian

    2011-01-01

    Given a set P of n coloured points on the real line, we study the problem of answering range α-majority (or "heavy hitter") queries on P. More specifically, for a query range Q, we want to return each colour that is assigned to more than an α-fraction of the points contained in Q. We present a new......((lg n/(α lglg n)). For constant values of α, this improved query time matches an existing lower bound, for any data structure with polylogarithmic update time. We also generalize our data structure to handle sets of points in d-dimensions, for d ≥ 2, as well as dynamic arrays, in which each entry...

  14. Neutron sensitivity and detection efficiency of 3He and 10BF3 counters

    International Nuclear Information System (INIS)

    Khokonov, A. Kh.; Savoiskii, Yu. V.; Kamarzaev, A. V.

    2010-01-01

    An analytic relationship between the efficiency, sensitivity, and the coefficient of working-isotope utilization is established for gas-filled cylindrical thermal-neutron counters. This dependence is expressed in terms of the ratio of the characteristic length of a counter to its diameter. The characteristic size is introduced as the ratio of the total absorption cross section to the length of the counter. The parameters of basic 3 He and 10 BF 3 counters used in NM-64 neutron monitors are calculated.

  15. Understanding synthesis imaging dynamic range

    Science.gov (United States)

    Braun, R.

    2013-03-01

    We develop a general framework for quantifying the many different contributions to the noise budget of an image made with an array of dishes or aperture array stations. Each noise contribution to the visibility data is associated with a relevant correlation timescale and frequency bandwidth so that the net impact on a complete observation can be assessed when a particular effect is not captured in the instrumental calibration. All quantities are parameterised as function of observing frequency and the visibility baseline length. We apply the resulting noise budget analysis to a wide range of existing and planned telescope systems that will operate between about 100 MHz and 5 GHz to ascertain the magnitude of the calibration challenges that they must overcome to achieve thermal noise limited performance. We conclude that calibration challenges are increased in several respects by small dimensions of the dishes or aperture array stations. It will be more challenging to achieve thermal noise limited performance using 15 m class dishes rather than the 25 m dishes of current arrays. Some of the performance risks are mitigated by the deployment of phased array feeds and more with the choice of an (alt,az,pol) mount, although a larger dish diameter offers the best prospects for risk mitigation. Many improvements to imaging performance can be anticipated at the expense of greater complexity in calibration algorithms. However, a fundamental limitation is ultimately imposed by an insufficient number of data constraints relative to calibration variables. The upcoming aperture array systems will be operating in a regime that has never previously been addressed, where a wide range of effects are expected to exceed the thermal noise by two to three orders of magnitude. Achieving routine thermal noise limited imaging performance with these systems presents an extreme challenge. The magnitude of that challenge is inversely related to the aperture array station diameter.

  16. BF3 x Et2O-mediated cascade cyclizations: synthesis of schweinfurthins F and G.

    Science.gov (United States)

    Mente, Nolan R; Neighbors, Jeffrey D; Wiemer, David F

    2008-10-17

    The total synthesis of the natural stilbene (+)-schweinfurthin G (8) has been accomplished through a sequence based on an efficient cationic cascade cyclization. This cascade process is initiated by Lewis acid promoted ring opening of an epoxide and terminated through a novel reaction with a phenolic oxygen "protected" as its MOM ether. Several Lewis acids have been examined for their ability to induce this new reaction, and BF3 x Et2O was found to be the most effective. The only major byproduct under these conditions was one where the expected secondary alcohol was found as its MOM ether derivative (e.g., 30). While this byproduct could be converted to the original target compound through hydrolysis, it also could be employed as a protected alcohol to allow preparation of a benzylic phosphonate (43) without dehydration of the secondary alcohol. The resulting phosphonate was employed in a Horner-Wadsworth-Emmons condensation with an aldehyde representing the right half of the target compounds, an approach complementary to previous studies based on condensation of a right-half phosphonate and a left-half aldehyde.

  17. BF3.SiO2: an efficient catalyst for the synthesis of azo dyes at room temperature

    Directory of Open Access Journals (Sweden)

    Bi Bi Fatemeh Mirjalili

    2012-07-01

    Full Text Available A rapid one-pot method has been developed for the synthesis of azo dyes via ‎sequential diazotization–diazo coupling of aromatic amines with coupling agents at room ‎temperature in the presence of BF3.SiO2 as acidic catalyst. The obtained aryl diazonium salts bearing silica supported boron tri-flouride counter ion‎ was sufficiently stable to be kept at room ‎temperature in the dry state.‎

  18. Three-dimensional dynamic range reduction techniques

    Science.gov (United States)

    Harding, Kevin G.; Qian, Xiaoping

    2004-02-01

    A significant limitation of the application of 3D structured light systems has been the large dynamic range of reflectivity of typical parts such as machined parts. The advent of digital cameras have helped this problem to some extent by providing a larger dynamic range of detection, but often parts must still be coated with white paint or powder to get a good enough return for 3D measurement techniques such as structured light. This paper will present an overview of methods that have been used to minimize the range of light reflections from many parts including polarization, multiple exposure, multiple viewing and masking techniques. Also presented will be methods of analysis such as phase analysis techniques which can provide improved robustness. Finally, we will discuss the pros and cons of these options as applied to the application of 3D structured light techniques to machined metal parts.

  19. High dynamic range imaging sensors and architectures

    CERN Document Server

    Darmont, Arnaud

    2013-01-01

    Illumination is a crucial element in many applications, matching the luminance of the scene with the operational range of a camera. When luminance cannot be adequately controlled, a high dynamic range (HDR) imaging system may be necessary. These systems are being increasingly used in automotive on-board systems, road traffic monitoring, and other industrial, security, and military applications. This book provides readers with an intermediate discussion of HDR image sensors and techniques for industrial and non-industrial applications. It describes various sensor and pixel architectures capable

  20. Range data in vehicle dynamic simulation

    OpenAIRE

    Nybacka, Mikael; Fredriksson, Håkan; Hyyppä, Kalevi

    2009-01-01

    This paper presents a way to merge range data into the vehicle dynamic simulation software CarSim 7.1. The range data consists of measurements describing the surface of a road, and thus, creates a close to real life 3D simulation environment. This reduces the discrepancy between the real life tests and simulation of vehicle suspension systems, dampers, springs, etc. It is important for the vehicle industry to represent a real life environment in the simulation software in order to increase th...

  1. Perceptual Contrast Enhancement with Dynamic Range Adjustment.

    Science.gov (United States)

    Zhang, Hong; Li, Yuecheng; Chen, Hao; Yuan, Ding; Sun, Mingui

    2013-12-01

    Recent years, although great efforts have been made to improve its performance, few Histogram equalization (HE) methods take human visual perception (HVP) into account explicitly. The human visual system (HVS) is more sensitive to edges than brightness. This paper proposes to take use of this nature intuitively and develops a perceptual contrast enhancement approach with dynamic range adjustment through histogram modification. The use of perceptual contrast connects the image enhancement problem with the HVS. To pre-condition the input image before the HE procedure is implemented, a perceptual contrast map (PCM) is constructed based on the modified Difference of Gaussian (DOG) algorithm. As a result, the contrast of the image is sharpened and high frequency noise is suppressed. A modified Clipped Histogram Equalization (CHE) is also developed which improves visual quality by automatically detecting the dynamic range of the image with improved perceptual contrast. Experimental results show that the new HE algorithm outperforms several state-of-the-art algorithms in improving perceptual contrast and enhancing details. In addition, the new algorithm is simple to implement, making it suitable for real-time applications.

  2. Mitochondrial uncouplers with an extraordinary dynamic range.

    Science.gov (United States)

    Lou, Phing-How; Hansen, Birgit S; Olsen, Preben H; Tullin, Søren; Murphy, Michael P; Brand, Martin D

    2007-10-01

    We have discovered that some weak uncouplers (typified by butylated hydroxytoluene) have a dynamic range of more than 10(6) in vitro: the concentration giving measurable uncoupling is less than one millionth of the concentration causing full uncoupling. They achieve this through a high-affinity interaction with the mitochondrial adenine nucleotide translocase that causes significant but limited uncoupling at extremely low uncoupler concentrations, together with more conventional uncoupling at much higher concentrations. Uncoupling at the translocase is not by a conventional weak acid/anion cycling mechanism since it is also caused by substituted triphenylphosphonium molecules, which are not anionic and cannot protonate. Covalent attachment of the uncoupler to a mitochondrially targeted hydrophobic cation sensitizes it to membrane potential, giving a small additional effect. The wide dynamic range of these uncouplers in isolated mitochondria and intact cells reveals a novel allosteric activation of proton transport through the adenine nucleotide translocase and provides a promising starting point for designing safer uncouplers for obesity therapy.

  3. Allee dynamics: Growth, extinction and range expansion

    Science.gov (United States)

    Bose, Indrani; Pal, Mainak; Karmakar, Chiranjit

    In population biology, the Allee dynamics refer to negative growth rates below a critical population density. In this paper, we study a reaction-diffusion (RD) model of popoulation growth and dispersion in one dimension, which incorporates the Allee effect in both the growth and mortatility rates. In the absence of diffusion, the bifurcation diagram displays regions of both finite population density and zero population density, i.e. extinction. The early signatures of the transition to extinction at the bifurcation point are computed in the presence of additive noise. For the full RD model, the existence of traveling wave solutions of the population density is demonstrated. The parameter regimes in which the traveling wave advances (range expansion) and retreats are identified. In the weak Allee regime, the transition from the pushed to the pulled wave is shown as a function of the mortality rate constant. The results obtained are in agreement with the recent experimental observations on budding yeast populations.

  4. Theoretical investigation of force field and vibrational spectrum of BF3 molecule by MO LCAO SCF method

    International Nuclear Information System (INIS)

    Ozerova, V.M.; Solomonik, V.G.; Krasnov, K.S.

    1982-01-01

    Non-empirical calculations of equilibrium internuclear distances, force constants, frequencies of normal vibrations, isotope shifts and vibration intensities in IR spectrum of BF 3 molecule have been made by MO LCAO SCF method using three bases of grouped gauss functions: DZ (9s5p/4s2p), TZ(10s6p/5s3p) and TZ+P (10s6p1d/5s3p1d). All the three bases lead to the results which are in good agreement with the experimental data. For instance, theoretical values of vibration frequencies differ from the experimental ones by average 3.2; 2.4 and 7.0% in the bases DZ, TZ and TZ+P respectively

  5. The Energy Variation of the Sensitivity of a Polyethylene Moderated BF3 Proportional Counter

    International Nuclear Information System (INIS)

    Fraeki, R.; Leimdoerfer, M.; Malmskog, S.

    1962-11-01

    The variation with neutron energy of the sensitivity of a polyethylene moderated boron counter has been investigated experimentally at 2.3 MeV, 550 keV, 210 keV, 110 keV, 340 eV and 5 eV, and theoretically by the multigroup diffusion method in the same range. Different moderator thicknesses up to 10 cm were considered Results show good agreement between experimental and theoretical sensitivities for the keV and MeV energies, while a discrepancy of the order of a factor 2 at the most is obtained in the eV region

  6. Photonic limiters with enhanced dynamic range

    Science.gov (United States)

    Kononchuk, Rodion; Limberopoulos, Nicholaos; Anisimov, Igor; Vitebskiy, Ilya; Chabanov, Andrey

    2018-02-01

    Optical limiters transmit low intensity input light while blocking input light with the intensity exceeding certain limiting threshold. Conventional passive limiters utilize nonlinear optical materials, which are transparent at low light intensity and turn absorptive at high intensity. Strong nonlinear absorption, though, can result in over- heating and destruction of the limiter. Another problem is that the limiting threshold provided by the available optical material with nonlinear absorption is too high for many applications. To address the above problems, the nonlinear material can be incorporated in a photonic structure with engineered dispersion. At low intensity, the photonic structure can display resonant transmission via localized mode(s), while at high intensity the resonant transmission can disappear, and the entire stack can become highly re ective (not absorptive) within a broad frequency range. In the proposed design, the transition from the resonant transmission at low intensity to nearly total re ectivity at high intensity does not rely on nonlinear absorption; instead, it requires only a modest change in the refractive index of the nonlinear material. The latter implies a dramatic increase in the dynamic range of the limiter. The main idea is to eliminate the high-intensity resonant transmission by decoupling the localized (resonant) modes from the input light, rather than suppressing those modes using nonlinear absorption. Similar approach can be used for light modulation and switching.

  7. On chirality transfer in electron donor-acceptor complexes. A prediction for the sulfinimine···BF3 system.

    Science.gov (United States)

    Rode, Joanna E; Dobrowolski, Jan Cz

    2012-01-01

    Stabilization energies of the electron donor-acceptor sulfinimine···BF(3) complexes calculated at either the B3LYP/aug-cc-pVTZ or the MP2/aug-cc-pVTZ level do not allow to judge, whether the N- or O-atom in sulfinimine is stronger electron-donor to BF(3) . The problem seems to be solvable because chirality transfer phenomenon between chiral sulfinimine and achiral BF(3) is expected to be vibrational circular dichroism (VCD) active. Moreover, the bands associated with the achiral BF(3) molecule are predicted to be the most intense in the entire spectrum. However, the VCD band robustness analyses show that most of the chirality transfer modes of BF(3) are unreliable. Conversely, variation of VCD intensity with change of intermolecular distance, angle, and selected dihedrals between the complex partners shows that to establish the robustness of chirality transfer mode. It is also necessary to determine the influence of the potential energy surface (PES) shape on the VCD intensity. At the moment, there is still no universal criterion for the chirality transfer mode robustness and the conclusions formulated based on one system cannot be directly transferred even to a quite similar one. However, it is certain that more attention should be focused on relation of PES shape and the VCD mode robustness problem. Copyright © 2011 Wiley Periodicals, Inc.

  8. Effect of Concentration of Catalyst (BF3-Diethyl Etherate on Synthesis of Polyester From Palm Fatty Acid Distillate (PFAD

    Directory of Open Access Journals (Sweden)

    Renita Manurung

    2013-10-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Palm Fatty Acid Distillate (PFAD can be used as raw material for synthesis polyester. The aim of this research is to synthesis of polyester and to determine the effect of concentration of catalyst on polymerization methyl ester PFAD. The esterification stage was done at temperature 70oC, reaction time 120 minute, reactant ratio 1:8 (PFAD: methanol, concentration of catalyst (H2SO4 1% (w/w PFAD; polymerization stage was done at temperature 126-132°C, polymerization reaction time 4 hours; variation of concentration of catalyst (BF3-diethyl etherate 0%, 6.9%, 9.2%, 11.5% (w/w methyl ester; and polyesterification stage was done at temperature 175-200 oC, reactant ratios (w/w 1:1 (polymerized ME : ethylene glycol, reaction time 4 hours and all of stage was stirred at 150 rpm. The results showed, in the esterification stage was obtained methyl ester with iodine value 77.29 g I2/100 g, viscosity 6.90 cP, density 859.91 kg/m3 and analysis by using GC-MS showed that the purity of methyl ester was 82.23% and molecular weight 267.97 g/mol. Decreasing in iodine value from 77.29 I2 g/100 g to 74.97-59.99 g I2/100 g indicated that the polymerization process had taken place. In polyesterification stage was obtained light brown colored

  9. High dynamic range image acquisition based on multiplex cameras

    Science.gov (United States)

    Zeng, Hairui; Sun, Huayan; Zhang, Tinghua

    2018-03-01

    High dynamic image is an important technology of photoelectric information acquisition, providing higher dynamic range and more image details, and it can better reflect the real environment, light and color information. Currently, the method of high dynamic range image synthesis based on different exposure image sequences cannot adapt to the dynamic scene. It fails to overcome the effects of moving targets, resulting in the phenomenon of ghost. Therefore, a new high dynamic range image acquisition method based on multiplex cameras system was proposed. Firstly, different exposure images sequences were captured with the camera array, using the method of derivative optical flow based on color gradient to get the deviation between images, and aligned the images. Then, the high dynamic range image fusion weighting function was established by combination of inverse camera response function and deviation between images, and was applied to generated a high dynamic range image. The experiments show that the proposed method can effectively obtain high dynamic images in dynamic scene, and achieves good results.

  10. Calculation of the reaction rate and response matrix of a neutron spectroscopy consisting of a water sphere of variable diameter and BF3 detector using the MCNP5-beta code

    International Nuclear Information System (INIS)

    Albashir, K.; Nahili, M.; Al-Zawahera, S.

    2015-01-01

    The MCNP5-beta code was used to calculate the reaction rate 1 0B(n,α) 7 Li and the neutron energy response matrix of a neutron spectrometer consisting of a water sphere with variable diameter and detector BF 3 using point and disk neutron sources 2 41Am-Be. The reaction rate and the response matrix of disk neutron source shows higher value than these obtained from the point neutron source. The response of the matrix disk neutron source in the energy range from 4.14x10 - 7 to 11.09 MeV show a maximum value for sphere of 12 inch diameter, where the response with point neutron source stile increasing calculated value in this condition .The calculated values of neutron energy responses for a disk neutron source agreed well with published results. (author)

  11. Perceptual Effects of Dynamic Range Compression in Popular Music Recordings

    DEFF Research Database (Denmark)

    Hjortkjær, Jens; Walther-Hansen, Mads

    2014-01-01

    The belief that the use of dynamic range compression in music mastering deteriorates sound quality needs to be formally tested. In this study normal hearing listeners were asked to evaluate popular music recordings in original versions and in remastered versions with higher levels of dynamic range...... compression. Surprisingly, the results failed to reveal any evidence of the effects of dynamic range compression on subjective preference or perceived depth cues. Perceptual data suggest that listeners are less sensitive than commonly believed to even high levels of compression. As measured in terms...

  12. A smart camera for High Dynamic Range imaging

    OpenAIRE

    Lapray, Pierre-Jean; Heyrman, Barthélémy; Ginhac, Dominique

    2013-01-01

    International audience; A camera or a video camera is able to capture only a part of a high dynamic range scene information. The same scene can be almost totally perceived by the human visual system. This is true especially for real scenes where the difference in light intensity between the dark areas and bright areas is high. The imaging technique which can overcome this problem is called HDR (High Dynamic Range). It produces images from a set of multiple LDR images (Low Dynamic Range), capt...

  13. Controlling the dynamic range of a Josephson parametric amplifier

    International Nuclear Information System (INIS)

    Eichler, Christopher; Wallraff, Andreas

    2014-01-01

    One of the central challenges in the development of parametric amplifiers is the control of the dynamic range relative to its gain and bandwidth, which typically limits quantum limited amplification to signals which contain only a few photons per inverse bandwidth. Here, we discuss the control of the dynamic range of Josephson parametric amplifiers by using Josephson junction arrays. We discuss gain, bandwidth, noise, and dynamic range properties of both a transmission line and a lumped element based parametric amplifier. Based on these investigations we derive useful design criteria, which may find broad application in the development of practical parametric amplifiers. (orig.)

  14. Dynamics of range margins for metapopulations under climate change

    Science.gov (United States)

    Anderson, B.J.; Akçakaya, H.R.; Araújo, M.B.; Fordham, D.A.; Martinez-Meyer, E.; Thuiller, W.; Brook, B.W.

    2009-01-01

    We link spatially explicit climate change predictions to a dynamic metapopulation model. Predictions of species' responses to climate change, incorporating metapopulation dynamics and elements of dispersal, allow us to explore the range margin dynamics for two lagomorphs of conservation concern. Although the lagomorphs have very different distribution patterns, shifts at the edge of the range were more pronounced than shifts in the overall metapopulation. For Romerolagus diazi (volcano rabbit), the lower elevation range limit shifted upslope by approximately 700 m. This reduced the area occupied by the metapopulation, as the mountain peak currently lacks suitable vegetation. For Lepus timidus (European mountain hare), we modelled the British metapopulation. Increasing the dispersive estimate caused the metapopulation to shift faster on the northern range margin (leading edge). By contrast, it caused the metapopulation to respond to climate change slower, rather than faster, on the southern range margin (trailing edge). The differential responses of the leading and trailing range margins and the relative sensitivity of range limits to climate change compared with that of the metapopulation centroid have important implications for where conservation monitoring should be targeted. Our study demonstrates the importance and possibility of moving from simple bioclimatic envelope models to second-generation models that incorporate both dynamic climate change and metapopulation dynamics. PMID:19324811

  15. Correlation between passive and dynamic range of rotation in lead ...

    African Journals Online (AJOL)

    ... between the passive hip range of movement and dynamic hip range during the golf swing of the trail hip. Clinicians and coaches should thus note that improving passive hip ROM might not be associated with an increased hip rotation utilised during the golf swing. Key words: Lower limb rotation; Golf swing biomechanics; ...

  16. Local dynamic range compensation for scanning electron microscope imaging system.

    Science.gov (United States)

    Sim, K S; Huang, Y H

    2015-01-01

    This is the extended project by introducing the modified dynamic range histogram modification (MDRHM) and is presented in this paper. This technique is used to enhance the scanning electron microscope (SEM) imaging system. By comparing with the conventional histogram modification compensators, this technique utilizes histogram profiling by extending the dynamic range of each tile of an image to the limit of 0-255 range while retains its histogram shape. The proposed technique yields better image compensation compared to conventional methods. © Wiley Periodicals, Inc.

  17. Time course of dynamic range adaptation in the auditory nerve

    Science.gov (United States)

    Wang, Grace I.; Dean, Isabel; Delgutte, Bertrand

    2012-01-01

    Auditory adaptation to sound-level statistics occurs as early as in the auditory nerve (AN), the first stage of neural auditory processing. In addition to firing rate adaptation characterized by a rate decrement dependent on previous spike activity, AN fibers show dynamic range adaptation, which is characterized by a shift of the rate-level function or dynamic range toward the most frequently occurring levels in a dynamic stimulus, thereby improving the precision of coding of the most common sound levels (Wen B, Wang GI, Dean I, Delgutte B. J Neurosci 29: 13797–13808, 2009). We investigated the time course of dynamic range adaptation by recording from AN fibers with a stimulus in which the sound levels periodically switch from one nonuniform level distribution to another (Dean I, Robinson BL, Harper NS, McAlpine D. J Neurosci 28: 6430–6438, 2008). Dynamic range adaptation occurred rapidly, but its exact time course was difficult to determine directly from the data because of the concomitant firing rate adaptation. To characterize the time course of dynamic range adaptation without the confound of firing rate adaptation, we developed a phenomenological “dual adaptation” model that accounts for both forms of AN adaptation. When fitted to the data, the model predicts that dynamic range adaptation occurs as rapidly as firing rate adaptation, over 100–400 ms, and the time constants of the two forms of adaptation are correlated. These findings suggest that adaptive processing in the auditory periphery in response to changes in mean sound level occurs rapidly enough to have significant impact on the coding of natural sounds. PMID:22457465

  18. High dynamic range (HDR) virtual bronchoscopy rendering for video tracking

    Science.gov (United States)

    Popa, Teo; Choi, Jae

    2007-03-01

    In this paper, we present the design and implementation of a new rendering method based on high dynamic range (HDR) lighting and exposure control. This rendering method is applied to create video images for a 3D virtual bronchoscopy system. One of the main optical parameters of a bronchoscope's camera is the sensor exposure. The exposure adjustment is needed since the dynamic range of most digital video cameras is narrower than the high dynamic range of real scenes. The dynamic range of a camera is defined as the ratio of the brightest point of an image to the darkest point of the same image where details are present. In a video camera exposure is controlled by shutter speed and the lens aperture. To create the virtual bronchoscopic images, we first rendered a raw image in absolute units (luminance); then, we simulated exposure by mapping the computed values to the values appropriate for video-acquired images using a tone mapping operator. We generated several images with HDR and others with low dynamic range (LDR), and then compared their quality by applying them to a 2D/3D video-based tracking system. We conclude that images with HDR are closer to real bronchoscopy images than those with LDR, and thus, that HDR lighting can improve the accuracy of image-based tracking.

  19. Perceptual Effects of Dynamic Range Compression in Popular Music Recordings

    DEFF Research Database (Denmark)

    Hjortkjær, Jens; Walther-Hansen, Mads

    2014-01-01

    There is a widespread belief that the increasing use of dynamic range compression in music mastering (the loudnesswar) deteriorates sound quality but experimental evidence of perceptual effects is lacking. In this study, normal hearing listeners were asked to evaluate popular music recordings...... of response consistency between different presentations of the same music suggests that listeners are less sensitive to even high levels of dynamic range compression than often argued....... in original versions and in remastered versions with higher levels of dynamic range compression. Surprisingly, we found no evidence of preference for the less compressed music. We also failed to find differences in ratings of perceived "depth" between the original and more compressed audio. A low degree...

  20. Molecular Orbital and Density Functional Study of the Formation, Charge Transfer, Bonding and the Conformational Isomerism of the Boron Trifluoride (BF3 and Ammonia (NH3 Donor-Acceptor Complex

    Directory of Open Access Journals (Sweden)

    Dulal C. Ghosh

    2004-09-01

    Full Text Available The formation of the F3B–NH3 supermolecule by chemical interaction of its fragment parts, BF3 and NH3, and the dynamics of internal rotation about the ‘B–N’ bond have been studied in terms of parameters provided by the molecular orbital and density functional theories. It is found that the pairs of frontier orbitals of the interacting fragments have matching symmetry and are involved in the charge transfer interaction. The donation process stems from the HOMO of the donor into the LUMO of the acceptor and simultaneously, back donation stems from the HOMO of acceptor into the LUMO of the donor. The density functional computation of chemical activation in the donor and acceptor fragments, associated with the physical process of structural reorganization just prior to the event of chemical reaction, indicates that BF3 becomes more acidic and NH3 becomes more basic, compared to their separate equilibrium states. Theoretically it is observed that the chemical reaction event of the formation of the supermolecule from its fragment parts is in accordance with the chemical potential equalization principle of the density functional theory and the electronegativity equalization principle of Sanderson. The energetics of the chemical reaction, the magnitude of the net charge transfer and the energy of the newly formed bond are quite consistent, both internally and with the principle of maximum hardness, PMH. The dynamics of the internal rotation of one part with respect to the other part of the supermolecule about the ‘B–N’ bond mimics the pattern of the conformational isomerism of the isostructural ethane molecule. It is also observed that the dynamics and evolution of molecular conformations as a function of dihedral angles is also in accordance with the principle of maximum hardness, PMH. Quite consistent with spectroscopic predictions, the height of the molecule

  1. High dynamic range processing for magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Andy H Hung

    Full Text Available To minimize feature loss in T1- and T2-weighted MRI by merging multiple MR images acquired at different TR and TE to generate an image with increased dynamic range.High Dynamic Range (HDR processing techniques from the field of photography were applied to a series of acquired MR images. Specifically, a method to parameterize the algorithm for MRI data was developed and tested. T1- and T2-weighted images of a number of contrast agent phantoms and a live mouse were acquired with varying TR and TE parameters. The images were computationally merged to produce HDR-MR images. All acquisitions were performed on a 7.05 T Bruker PharmaScan with a multi-echo spin echo pulse sequence.HDR-MRI delineated bright and dark features that were either saturated or indistinguishable from background in standard T1- and T2-weighted MRI. The increased dynamic range preserved intensity gradation over a larger range of T1 and T2 in phantoms and revealed more anatomical features in vivo.We have developed and tested a method to apply HDR processing to MR images. The increased dynamic range of HDR-MR images as compared to standard T1- and T2-weighted images minimizes feature loss caused by magnetization recovery or low SNR.

  2. [X-ray radiographic imaging technique with high dynamic range].

    Science.gov (United States)

    Liu, Bin; Wang, Li-Ming; Su, Xin-Yan

    2014-04-01

    In conventional X-ray radiographic imaging system with a fixed energy parameter, the acquired X-ray images are usually overexposed and have no useful information available. It is due to some constraints, like special structure of component, different attenuation coefficients of materials and dynamic range of optoelectronic devices. When maximum of transmitted X-ray luminous exceed capacity limitation of X-ray radiographic imaging system in one scene, the device up to saturate. Also when minimum of transmitted X-ray luminous is below the thermal noise level of imaging system, no useful information is available for imaging. To solve the problem of difficulties in acquiring transmitted X-ray luminous in a wide dynamic range by conventional X-ray radiographic imaging system, we put forward a new X-ray radiographic imaging technique with high dynamic range based on adjusting tube voltage. In the article, the influence by charge capacity of X-ray radiographic imaging system on effective irradiating thickness is analyzed. Through experiments of some standard samples, we gained the relationship between voltage range of X-ray tube and materials or structure of component for best testing sensitivity. Then we put forward an adjusting strategy of tube voltage and effective subgraphs extraction method from acquired raw X-ray images. By the mentioned method, we carried out X-ray radiographic imaging experiments with high dynamic range for components with thickness from 0 to 20 mm. The results show that X-ray radiographic imaging technique with high dynamic range is effective to realize imaging for some components with different thickness. It is available for us to find more detailed projection information from fusion images.

  3. Perceptual Effects of Dynamic Range Compression in Popular Music Recordings

    DEFF Research Database (Denmark)

    Hjortkjær, Jens; Walther-Hansen, Mads

    2014-01-01

    There is a widespread belief that the increasing use of dynamic range compression in music mastering (the loudnesswar) deteriorates sound quality but experimental evidence of perceptual effects is lacking. In this study, normal hearing listeners were asked to evaluate popular music recordings...

  4. Effects of dynamic-range compression on temporal acuity

    DEFF Research Database (Denmark)

    Wiinberg, Alan; Jepsen, Morten Løve; Epp, Bastian

    2016-01-01

    processing, temporal modulation transfer functions (TMTFs) and “supra-threshold” modulation-depth discrimination (MDD) thresholds were obtained in normal-hearing (NH) and hearing-impaired (HI) listeners with and without wide-dynamic range compression (WDRC). The TMTFs were obtained using tonal carriers of 1...

  5. Dynamic Range Across Music Genres and the Perception of Dynamic Compression in Hearing-Impaired Listeners

    Science.gov (United States)

    Kirchberger, Martin

    2016-01-01

    Dynamic range compression serves different purposes in the music and hearing-aid industries. In the music industry, it is used to make music louder and more attractive to normal-hearing listeners. In the hearing-aid industry, it is used to map the variable dynamic range of acoustic signals to the reduced dynamic range of hearing-impaired listeners. Hence, hearing-aided listeners will typically receive a dual dose of compression when listening to recorded music. The present study involved an acoustic analysis of dynamic range across a cross section of recorded music as well as a perceptual study comparing the efficacy of different compression schemes. The acoustic analysis revealed that the dynamic range of samples from popular genres, such as rock or rap, was generally smaller than the dynamic range of samples from classical genres, such as opera and orchestra. By comparison, the dynamic range of speech, based on recordings of monologues in quiet, was larger than the dynamic range of all music genres tested. The perceptual study compared the effect of the prescription rule NAL-NL2 with a semicompressive and a linear scheme. Music subjected to linear processing had the highest ratings for dynamics and quality, followed by the semicompressive and the NAL-NL2 setting. These findings advise against NAL-NL2 as a prescription rule for recorded music and recommend linear settings. PMID:26868955

  6. Dynamic Range Across Music Genres and the Perception of Dynamic Compression in Hearing-Impaired Listeners.

    Science.gov (United States)

    Kirchberger, Martin; Russo, Frank A

    2016-02-10

    Dynamic range compression serves different purposes in the music and hearing-aid industries. In the music industry, it is used to make music louder and more attractive to normal-hearing listeners. In the hearing-aid industry, it is used to map the variable dynamic range of acoustic signals to the reduced dynamic range of hearing-impaired listeners. Hence, hearing-aided listeners will typically receive a dual dose of compression when listening to recorded music. The present study involved an acoustic analysis of dynamic range across a cross section of recorded music as well as a perceptual study comparing the efficacy of different compression schemes. The acoustic analysis revealed that the dynamic range of samples from popular genres, such as rock or rap, was generally smaller than the dynamic range of samples from classical genres, such as opera and orchestra. By comparison, the dynamic range of speech, based on recordings of monologues in quiet, was larger than the dynamic range of all music genres tested. The perceptual study compared the effect of the prescription rule NAL-NL2 with a semicompressive and a linear scheme. Music subjected to linear processing had the highest ratings for dynamics and quality, followed by the semicompressive and the NAL-NL2 setting. These findings advise against NAL-NL2 as a prescription rule for recorded music and recommend linear settings. © The Author(s) 2016.

  7. Dynamic Range Across Music Genres and the Perception of Dynamic Compression in Hearing-Impaired Listeners

    Directory of Open Access Journals (Sweden)

    Martin Kirchberger

    2016-02-01

    Full Text Available Dynamic range compression serves different purposes in the music and hearing-aid industries. In the music industry, it is used to make music louder and more attractive to normal-hearing listeners. In the hearing-aid industry, it is used to map the variable dynamic range of acoustic signals to the reduced dynamic range of hearing-impaired listeners. Hence, hearing-aided listeners will typically receive a dual dose of compression when listening to recorded music. The present study involved an acoustic analysis of dynamic range across a cross section of recorded music as well as a perceptual study comparing the efficacy of different compression schemes. The acoustic analysis revealed that the dynamic range of samples from popular genres, such as rock or rap, was generally smaller than the dynamic range of samples from classical genres, such as opera and orchestra. By comparison, the dynamic range of speech, based on recordings of monologues in quiet, was larger than the dynamic range of all music genres tested. The perceptual study compared the effect of the prescription rule NAL-NL2 with a semicompressive and a linear scheme. Music subjected to linear processing had the highest ratings for dynamics and quality, followed by the semicompressive and the NAL-NL2 setting. These findings advise against NAL-NL2 as a prescription rule for recorded music and recommend linear settings.

  8. In-Vivo High Dynamic Range Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Jensen, Jørgen Arendt

    2015-01-01

    Current vector flow systems are limited in their detectable range of blood flow velocities. Previous work on phantoms has shown that the velocity range can be extended using synthetic aperture directional beamforming combined with an adaptive multi-lag approach. This paper presents a first invivo...... example with a high dynamic velocity range. Velocities with an order of magnitude apart are detected on the femoral artery of a 41 years old healthy individual. Three distinct heart cycles are captured during a 3 secs acquisition. The estimated vector velocities are compared against each other within...

  9. Entanglement Growth in Quench Dynamics with Variable Range Interactions

    Directory of Open Access Journals (Sweden)

    J. Schachenmayer

    2013-09-01

    Full Text Available Studying entanglement growth in quantum dynamics provides both insight into the underlying microscopic processes and information about the complexity of the quantum states, which is related to the efficiency of simulations on classical computers. Recently, experiments with trapped ions, polar molecules, and Rydberg excitations have provided new opportunities to observe dynamics with long-range interactions. We explore nonequilibrium coherent dynamics after a quantum quench in such systems, identifying qualitatively different behavior as the exponent of algebraically decaying spin-spin interactions in a transverse Ising chain is varied. Computing the buildup of bipartite entanglement as well as mutual information between distant spins, we identify linear growth of entanglement entropy corresponding to propagation of quasiparticles for shorter-range interactions, with the maximum rate of growth occurring when the Hamiltonian parameters match those for the quantum phase transition. Counterintuitively, the growth of bipartite entanglement for long-range interactions is only logarithmic for most regimes, i.e., substantially slower than for shorter-range interactions. Experiments with trapped ions allow for the realization of this system with a tunable interaction range, and we show that the different phenomena are robust for finite system sizes and in the presence of noise. These results can act as a direct guide for the generation of large-scale entanglement in such experiments, towards a regime where the entanglement growth can render existing classical simulations inefficient.

  10. Extending the Dynamic Range of a Time Projection Chamber

    Science.gov (United States)

    Estee, Justin; S πRIT Collaboration

    2017-09-01

    The use of Time Projection Chambers (TPCs) in intermediate heavy ion reactions faces some challenges in addressing the energy losses that range from the small energy loss of relativistic pions to the large energy loss of slow moving heavy ions. A typical trade-off can be to set the smallest desired signals to be well within the lower limits of the dynamic range of the electronics while allowing for some larger signals to saturate the electronics. With wire plane anodes, signals from readout pads further away from the track remain unsaturated and allow signals from tracks with saturated pads to be accurately recovered. We illustrate this technique using data from the SAMURAI Pion-Reconstruction and Ion-Tracker (S πRIT) TPC , which recently measured pions and light charged particles in collisions of Sn+Sn isotopes. Our method exploits knowledge of how the induced charge distribution depends on the distance from the track to smoothly extend dynamic range even when some of the pads in the track are saturated. To accommodate the analysis of slow moving heavy ions, we have extended the Bichsel energy loss distributions to handle slower moving ions as well. In this talk, I will discuss a combined approach which successfully extends the dynamic range of the TPC electronics. This work is supported by the U.S. DOE under Grant Nos. DE-SC0014530, DE-NA0002923, US NSF Grant No. PHY-1565546 and the Japan MEXT KAKENHI Grant No. 24105004.

  11. The use of AgNO3/BF3.Et2O and HNO3/Al(H2PO43 systems in the synthesis of aryl thiosulfonates

    Directory of Open Access Journals (Sweden)

    Edson Anjos Santos

    2012-06-01

    Full Text Available The thiosulfonates are a class of compounds of great industrial importance. It is worth noting that the aryl thiosulfonates present several biological activities. The synthesis of these compounds is known in the literature although; only a few make use of thiols as the sole starting material. This work shows the use of two reaction systems employed for the synthesis of nitrophenols, AgNO3/BF3.EtO2 (I and HNO3/Al(H2PO43 (II, as an alternative to the preparation of aryl thiosulfonates. The use of system I led to higher yields (72-76% then system II (56-61%. These methodologies have not been reported before for the synthesis of these compounds and the products were obtained with good purity.

  12. Fluorescence-based Broad Dynamic Range Viscosity Probes.

    Science.gov (United States)

    Dragan, Anatoliy; Graham, August E; Geddes, Chris D

    2014-03-01

    We introduce two new fluorescent viscosity probes, SYBR Green (SG) and PicoGreen (PG), that we have studied over a broad range of viscosity and in collagen solutions. In water, both dyes have low quantum yields and excited state lifetimes, while in viscous solvents or in complex with DNA both parameters dramatically (300-1000-fold) increase. We show that in log-log scale the dependence of the dyes' quantum yield vs. viscosity is linear, the slope of which is sensitive to temperature. Application of SG and PG, as a fluorescence-based broad dynamic range viscosity probes, to the life sciences is discussed.

  13. POTENTIALS OF IMAGE BASED ACTIVE RANGING TO CAPTURE DYNAMIC SCENES

    Directory of Open Access Journals (Sweden)

    B. Jutzi

    2012-09-01

    Full Text Available Obtaining a 3D description of man-made and natural environments is a basic task in Computer Vision and Remote Sensing. To this end, laser scanning is currently one of the dominating techniques to gather reliable 3D information. The scanning principle inherently needs a certain time interval to acquire the 3D point cloud. On the other hand, new active sensors provide the possibility of capturing range information by images with a single measurement. With this new technique image-based active ranging is possible which allows capturing dynamic scenes, e.g. like walking pedestrians in a yard or moving vehicles. Unfortunately most of these range imaging sensors have strong technical limitations and are not yet sufficient for airborne data acquisition. It can be seen from the recent development of highly specialized (far-range imaging sensors – so called flash-light lasers – that most of the limitations could be alleviated soon, so that future systems will be equipped with improved image size and potentially expanded operating range. The presented work is a first step towards the development of methods capable for application of range images in outdoor environments. To this end, an experimental setup was set up for investigating these proposed possibilities. With the experimental setup a measurement campaign was carried out and first results will be presented within this paper.

  14. Generational Spreading Speed and the Dynamics of Population Range Expansion.

    Science.gov (United States)

    Bateman, Andrew W; Neubert, Michael G; Krkošek, Martin; Lewis, Mark A

    2015-09-01

    Some of the most fundamental quantities in population ecology describe the growth and spread of populations. Population dynamics are often characterized by the annual rate of increase, λ, or the generational rate of increase, R0. Analyses involving R0 have deepened our understanding of disease dynamics and life-history complexities beyond that afforded by analysis of annual growth alone. While range expansion is quantified by the annual spreading speed, a spatial analog of λ, an R0-like expression for the rate of spread is missing. Using integrodifference models, we derive the appropriate generational spreading speed for populations with complex (stage-structured) life histories. The resulting measure, relevant to locations near the expanding edge of a (re)colonizing population, incorporates both local population growth and explicit spatial dispersal rather than solely growth across a population, as is the case for R0. The calculations for generational spreading speed are often simpler than those for annual spreading speed, and analytic or partial analytic solutions can yield insight into the processes that facilitate or slow a population's spatial spread. We analyze the spatial dynamics of green crabs, sea otters, and teasel as examples to demonstrate the flexibility of our methods and the intuitive insights that they afford.

  15. First full dynamic range calibration of the JUNGFRAU photon detector

    Science.gov (United States)

    Redford, S.; Andrä, M.; Barten, R.; Bergamaschi, A.; Brückner, M.; Dinapoli, R.; Fröjdh, E.; Greiffenberg, D.; Lopez-Cuenca, C.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruat, M.; Ruder, C.; Schmitt, B.; Shi, X.; Thattil, D.; Tinti, G.; Vetter, S.; Zhang, J.

    2018-01-01

    The JUNGFRAU detector is a charge integrating hybrid silicon pixel detector developed at the Paul Scherrer Institut for photon science applications, in particular for the upcoming free electron laser SwissFEL. With a high dynamic range, analogue readout, low noise and three automatically switching gains, JUNGFRAU promises excellent performance not only at XFELs but also at synchrotrons in areas such as protein crystallography, ptychography, pump-probe and time resolved measurements. To achieve its full potential, the detector must be calibrated on a pixel-by-pixel basis. This contribution presents the current status of the JUNGFRAU calibration project, in which a variety of input charge sources are used to parametrise the energy response of the detector across four orders of magnitude of dynamic range. Building on preliminary studies, the first full calibration procedure of a JUNGFRAU 0.5 Mpixel module is described. The calibration is validated using alternative sources of charge deposition, including laboratory experiments and measurements at ESRF and LCLS. The findings from these measurements are presented. Calibrated modules have already been used in proof-of-principle style protein crystallography experiments at the SLS. A first look at selected results is shown. Aspects such as the conversion of charge to number of photons, treatment of multi-size pixels and the origin of non-linear response are also discussed.

  16. Mangrove microclimates alter seedling dynamics at the range edge.

    Science.gov (United States)

    Devaney, John L; Lehmann, Michael; Feller, Ilka C; Parker, John D

    2017-10-01

    Recent climate warming has led to asynchronous species migrations, with major consequences for ecosystems worldwide. In woody communities, localized microclimates have the potential to create feedback mechanisms that can alter the rate of species range shifts attributed to macroclimate drivers alone. Mangrove encroachment into saltmarsh in many areas is driven by a reduction in freeze events, and this encroachment can further modify local climate, but the subsequent impacts on mangrove seedling dynamics are unknown. We monitored microclimate conditions beneath mangrove canopies and adjacent open saltmarsh at a freeze-sensitive mangrove-saltmarsh ecotone and assessed survival of experimentally transplanted mangrove seedlings. Mangrove canopies buffered night time cooling during the winter, leading to interspecific differences in freeze damage on mangrove seedlings. However, mangrove canopies also altered biotic interactions. Herbivore damage was higher under canopies, leading to greater mangrove seedling mortality beneath canopies relative to saltmarsh. While warming-induced expansion of mangroves can lead to positive microclimate feedbacks, simultaneous fluctuations in biotic drivers can also alter seedling dynamics. Thus, climate change can drive divergent feedback mechanisms through both abiotic and biotic channels, highlighting the importance of vegetation-microclimate interactions as important moderators of climate driven range shifts. © 2017 by the Ecological Society of America.

  17. Unsymmetrical urea and thiourea derivatives: An efficient nano BF 3-SiO 2 catalyzed PEG-400 mediated sonochemical synthesis and biological evaluation

    Directory of Open Access Journals (Sweden)

    D. B. Janakiramudu

    2017-08-01

    Full Text Available An efficient and green approach has been developed for the synthesis of (substituted phenyl-3-(4-(4-nitrophenylthiophenylurea/thiourea derivatives 6(a-j using non-hazardous green solvent, PEG-400 under ultrasound irradiation conditions in the presence of a reusable silica-supported Lewis acid catalyst, nano-BF 3-SiO 2via simple addition reaction of 4-(4-nitrophenylthioaniline (4 with substituted phenyl isocyanates/isothiocyanates 5 (a-j. The advantages of developed method are convenient, offered higher yield of products with purity, less reaction time, easy work-up and reusability of the catalyst. Structures of the title products were established by IR, NMR ( 1H, 13C, mass spectral data and elemental analysis. Antimicrobial activity of the newly synthesized compounds was tested and the bio-screening data disclosed that urea derivatives, 6a and 6d, and thiourea derivatives, 6f, 6i and 6j showed potential antimicrobial activity against the growth of selected microorganisms.

  18. Low Power High Dynamic Range A/D Conversion Channel

    DEFF Research Database (Denmark)

    Marker-Villumsen, Niels; Rombach, Pirmin

    This work concerns the analysis of an adaptive analog-to-digital (A/D) conversion channel for use with a micro electromechanical system (MEMS) microphone for audio applications. The adaptive A/D conversion channel uses an automatic gain control (AGC) for adjusting the analog preamplifier gain...... in the conversion channel in order to avoid distortion for large input signals. In combination with a low resolution A/D converter (ADC) and a digital gain block, the adaptive A/D conversion channel achieves an extended dynamic range beyond that of the ADC. This in turn reduces the current consumption...... of the transient errors, an objective method based on the Perceived Evaluation of Audio Quality (PEAQ) method is investigated and compared with a subjective evaluation. The results of the evaluation provide key knowledge about the transient glitches from both a system and psychoacoustical point-of-view. Based...

  19. Picosecond X-ray streak camera dynamic range measurement

    Energy Technology Data Exchange (ETDEWEB)

    Zuber, C., E-mail: celine.zuber@cea.fr; Bazzoli, S.; Brunel, P.; Gontier, D.; Raimbourg, J.; Rubbelynck, C.; Trosseille, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Fronty, J.-P.; Goulmy, C. [Photonis SAS, Avenue Roger Roncier, BP 520, 19106 Brive Cedex (France)

    2016-09-15

    Streak cameras are widely used to record the spatio-temporal evolution of laser-induced plasma. A prototype of picosecond X-ray streak camera has been developed and tested by Commissariat à l’Énergie Atomique et aux Énergies Alternatives to answer the Laser MegaJoule specific needs. The dynamic range of this instrument is measured with picosecond X-ray pulses generated by the interaction of a laser beam and a copper target. The required value of 100 is reached only in the configurations combining the slowest sweeping speed and optimization of the streak tube electron throughput by an appropriate choice of high voltages applied to its electrodes.

  20. High-dynamic-range cationic two-photon photopolymerization

    Science.gov (United States)

    Boiko, Yuri B.; Costa, Joannes M.; Wang, Mark M.; Esener, Sadik C.

    2001-06-01

    Cationic-induced two-photon photopolymerization is demonstrated at 710 nm, using an isopropylthioxanthone/diarylidonium salt initiating system for the cationic polymerization of an epoxide. The polymerization threshold J2th is found to be approximately 1 GW/cm2, with a dynamic range of > 100, i.e. the material can be fully polymerized at intensities > 100 times the threshold level without damage. The polymerization rate R is found to be proportional to the m equals 1.7 power of the intensity, or R equals [C (J-J2th)]m equals [C (J-J2th)]1.7, which implies a significantly stronger localization of the photochemical response than that of free radical photoinitiators. R and J2th significantly improve when the concentration z of the initiator (onium salt) increases.

  1. An Integrated Tone Mapping for High Dynamic Range Image Visualization

    Science.gov (United States)

    Liang, Lei; Pan, Jeng-Shyang; Zhuang, Yongjun

    2018-01-01

    There are two type tone mapping operators for high dynamic range (HDR) image visualization. HDR image mapped by perceptual operators have strong sense of reality, but will lose local details. Empirical operators can maximize local detail information of HDR image, but realism is not strong. A common tone mapping operator suitable for all applications is not available. This paper proposes a novel integrated tone mapping framework which can achieve conversion between empirical operators and perceptual operators. In this framework, the empirical operator is rendered based on improved saliency map, which simulates the visual attention mechanism of the human eye to the natural scene. The results of objective evaluation prove the effectiveness of the proposed solution.

  2. High Precision Sunphotometer using Wide Dynamic Range (WDR) Camera Tracking

    Science.gov (United States)

    Liss, J.; Dunagan, S. E.; Johnson, R. R.; Chang, C. S.; LeBlanc, S. E.; Shinozuka, Y.; Redemann, J.; Flynn, C. J.; Segal-Rosenhaimer, M.; Pistone, K.; Kacenelenbogen, M. S.; Fahey, L.

    2016-12-01

    High Precision Sunphotometer using Wide Dynamic Range (WDR) Camera TrackingThe NASA Ames Sun-photometer-Satellite Group, DOE, PNNL Atmospheric Sciences and Global Change Division, and NASA Goddard's AERONET (AErosol RObotic NETwork) team recently collaborated on the development of a new airborne sunphotometry instrument that provides information on gases and aerosols extending far beyond what can be derived from discrete-channel direct-beam measurements, while preserving or enhancing many of the desirable AATS features (e.g., compactness, versatility, automation, reliability). The enhanced instrument combines the sun-tracking ability of the current 14-Channel NASA Ames AATS-14 with the sky-scanning ability of the ground-based AERONET Sun/sky photometers, while extending both AATS-14 and AERONET capabilities by providing full spectral information from the UV (350 nm) to the SWIR (1,700 nm). Strengths of this measurement approach include many more wavelengths (isolated from gas absorption features) that may be used to characterize aerosols and detailed (oversampled) measurements of the absorption features of specific gas constituents. The Sky Scanning Sun Tracking Airborne Radiometer (3STAR) replicates the radiometer functionality of the AATS-14 instrument but incorporates modern COTS technologies for all instruments subsystems. A 19-channel radiometer bundle design is borrowed from a commercial water column radiance instrument manufactured by Biospherical Instruments of San Diego California (ref, Morrow and Hooker)) and developed using NASA funds under the Small Business Innovative Research (SBIR) program. The 3STAR design also incorporates the latest in robotic motor technology embodied in Rotary actuators from Oriental motor Corp. having better than 15 arc seconds of positioning accuracy. Control system was designed, tested and simulated using a Hybrid-Dynamical modeling methodology. The design also replaces the classic quadrant detector tracking sensor with a

  3. Cochlear function tests in estimation of speech dynamic range.

    Science.gov (United States)

    Han, Jung Ju; Park, So Young; Park, Shi Nae; Na, Mi Sun; Lee, Philip; Han, Jae Sang

    2016-10-01

    The loss of active cochlear mechanics causes elevated thresholds, loudness recruitment, and reduced frequency selectivity. The problems faced by hearing-impaired listeners are largely related with reduced dynamic range (DR). The aim of this study was to determine which index of the cochlear function tests correlates best with the DR to speech stimuli. Audiological data on 516 ears with pure tone average (PTA) of ≤55 dB and word recognition score of ≥70% were analyzed. PTA, speech recognition threshold (SRT), uncomfortable loudness (UCL), and distortion product otoacoustic emission (DPOAE) were explored as the indices of cochlear function. Audiometric configurations were classified. Correlation between each index and the DR was assessed and multiple regression analysis was done. PTA and SRT demonstrated strong negative correlations with the DR (r = -0.788 and -0.860, respectively), while DPOAE sum was moderately correlated (r = 0.587). UCLs remained quite constant for the total range of the DR. The regression equation was Y (DR) = 75.238 - 0.719 × SRT (R(2 )=( )0.721, p equation.

  4. Dynamic range measurement and calibration of SiPMs

    Science.gov (United States)

    Bretz, T.; Hebbeker, T.; Lauscher, M.; Middendorf, L.; Niggemann, T.; Schumacher, J.; Stephan, M.; Bueno, A.; Navas, S.; Ruiz, A. G.

    2016-03-01

    Photosensors have played and will continue to play an important role in high-energy and Astroparticle cutting-edge experiments. As of today, the most common photon detection device in use is the photomultiplier tube (PMT). However, we are witnessing rapid progress in the field and new devices now show very competitive features when compared to PMTs. Among those state-of-the-art photo detectors, silicon photomultipliers (SiPMs) are a relatively new kind of semiconductor whose potential is presently studied by many laboratories. Their characteristics make them a very attractive candidate for future Astroparticle physics experiments recording fluorescence and Cherenkov light, both in the atmosphere and on the ground. Such applications may require the measurement of the light flux on the sensor for the purpose of energy reconstruction. This is a complex task due to the limited dynamic range of SiPMs and the presence of thermal and correlated noise. In this work we study the response of three SiPM types in terms of delivered charge when exposed to light pulses in a broad range of intensities: from single photon to saturation. The influence of the pulse time duration and the SiPM over-voltage on the response are also quantified. Based on the observed behaviour, a method is presented to reconstruct the real number of photons impinging on the SiPM surface directly from the measured SiPM charge. A special emphasis is placed on the description of the methodology and experimental design used to perform the measurements.

  5. Range use and dynamics in the agropastoral system of ...

    African Journals Online (AJOL)

    Occurrence of equilibrium and non equilibrium system dynamics in semiarid environments present serious management challenges. In these areas, resource management strategies are increasingly based on equilibrium rather than non equilibrium dynamics that assume simple system dynamics and strong coupling of ...

  6. Display of high dynamic range images under varying viewing conditions

    Science.gov (United States)

    Borer, Tim

    2017-09-01

    Recent demonstrations of high dynamic range (HDR) television have shown that superb images are possible. With the emergence of an HDR television production standard (ITU-R Recommendation BT.2100) last year, HDR television production is poised to take off. However research to date has focused principally on HDR image display only under "dark" viewing conditions. HDR television will need to be displayed at varying brightness and under varying illumination (for example to view sport in daytime or on mobile devices). We know, from common practice with conventional TV, that the rendering intent (gamma) should change under brighter conditions, although this is poorly quantified. For HDR the need to render images under varying conditions is all the more acute. This paper seeks to explore the issues surrounding image display under varying conditions. It also describes how visual adaptation is affected by display brightness, surround illumination, screen size and viewing distance. Existing experimental results are presented and extended to try to quantify these effects. Using the experimental results it is described how HDR images may be displayed so that they are perceptually equivalent under different viewing conditions. A new interpretation of the experimental results is reported, yielding a new, luminance invariant model for the appropriate display "gamma". In this way the consistency of HDR image reproduction should be improved, thereby better maintaining "creative intent" in television.

  7. Cationic two-photon induced polymerization with high dynamic range

    Science.gov (United States)

    Boiko, Yuri B.; Costa, Joannes; Wang, Mark M.; Esener, Sadik C.

    2001-05-01

    Cationic-induced two-photon photo-polymerization is demonstrated at 710 nm, using an isopropylthioxanthone / diarylidonium salt initiating system for the cationic polymerization of an epoxide. In-situ monitoring of the polymer conversion using interferometry allows for determination of the polymerization threshold J2th, polymerization rate R and its dependence of initiator's concentration z. Best J2th achieved is 1 GW/cm 2 , with a dynamic range of > 100, i.e. the material can be fully polymerized at intensities > 100 times the threshold level without damage. The R is found to be proportional to the m=1.7 power of the intensity, or R =[C(J-J2th)]m =[C(J-J2th)]1.7 , which implies a significantly stronger localization of the photochemical response than that of free radical photoinitiators. Both R and J2th significantly improve when the concentration z of the initiator (onium salt) increases, reduction of J2th exhibiting z -m trend.

  8. Infrared Lunar Laser Ranging at Calern : Impact on Lunar Dynamics

    Science.gov (United States)

    Viswanathan, Vishnu; Fienga, Agnes; Manche, Herve; Gastineau, Mickael; Courde, Clement; Torre, Jean Marie; Exertier, Pierre; Laskar, Jacques

    2017-04-01

    Introduction: Since 2015, in addition to the traditional green (532nm), infrared (1064nm) has been the preferred wavelength for lunar laser ranging at the Calern lunar laser ranging (LLR) site in France. Due to the better atmospheric transmission of IR with respect to Green, nearly 3 times the number of normal points have been obtained in IR than in Green [1]. Dataset: In our study, in addition to the historical data obtained from various other LLR sites, we include the recent IR normal points obtained from Calern over the 1 year time span (2015-2016), constituting about 4.2% of data spread over 46 years of LLR. Near even distribution of data provided by IR on both the spatial and temporal domain, helps us to improve constraints on the internal structure of the Moon modeled within the planetary ephemeris : INPOP [2]. Data reduction: IERS recommended models have been used in the data reduction software GINS (GRGS,CNES) [3]. Constraints provided by GRAIL [4], on the Lunar gravitational potential and Love numbers have been taken into account in the least-square fit procedure. Earth orientation parameters from KEOF series have been used as per a recent study [5]. Results: New estimates on the dynamical parameters of the lunar core will be presented. Acknowledgements: We thank the lunar laser ranging observers at Observatoire de la Côte d'Azur, France, McDonald Observatory, Texas, Haleakala Observatory, Hawaii, and Apache Point Observatory in New Mexico for providing LLR observations that made this study possible. The research described in this abstract was carried out at Geoazur-CNRS, France, as a part of a PhD thesis funded by Observatoire de Paris and French Ministry of Education and Research. References: [1] Clement C. et al. (2016) submitted to A&A [2] Fienga A. et al. (2015) Celest Mech Dyn Astr, 123: 325. doi:10.1007/s10569-015-9639-y [3] Viswanathan V. et al. (2015) EGU, Abstract 18, 13995 [4] Konopliv A. S. et al. (2013) J. Geophys. Res. Planets, 118, 1415

  9. Dynamics of Quantum Matter with Long-Range Entanglement

    Science.gov (United States)

    2013-06-07

    representation of its dynamics by the methods of gauge-gravity duality. A holographic effective field theory method will be developed by comparing the results...comments regarding this burden estimate or any other aspect of this collection of information, including suggesstions for reducing this burden, to...transition in two spatial dimensions. This project will study the theoretical representation of its dynamics by the methods of gauge-gravity duality. A

  10. Population dynamics of sugar maple through the southern portion of its range: implications for range migration

    Science.gov (United States)

    Justin L. Hart; Christopher M. Oswalt; Craig M. Turberville

    2014-01-01

    The range of sugar maple (Acer saccharum Marsh.) is expected to shift northward in accord with changing climate. However, a pattern of increased sugar maple abundance has been reported from sites throughout the eastern US. The goal of our study was to examine the stability of the sugar maple southern range boundary by analyzing its demography through...

  11. Real-time dynamic PC image generation techniques for high performance and high dynamic range fidelity

    Science.gov (United States)

    Bunfield, Dennis H.; Trimble, Darian E.; Fronckowiak, Thomas, Jr.; Ballard, Gary; Morris, Joesph

    2008-04-01

    AMRDEC has developed and implemented new techniques for rendering real-time 32-bit floating point energy-conserved dynamic scenes using commercial-off-the-shelf (COTS) Personal Computer (PC) based hardware and high performance nVidia Graphics Processing Units (GPU). The AMRDEC IGStudio rendering framework with the real-time Joint Scientific Image Generator (JSIG) core has been integrated into numerous AMRDEC Hardware-in-the-loop (HWIL) facilities, successfully replacing the lower fidelity legacy SGI hardware and software. JSIG uses high dynamic range unnormalized radiometric 32-bit floating point rendering through the use of GPU frame buffer objects (FBOs). A high performance nested zoom anti-aliasing (NZAA) technique was developed to address performance and geometric errors of past zoom anti-aliasing (ZAA) implementations. The NZAA capability for multi-object and occluded object representations includes: cluster ZAA, object ZAA, sub-object ZAA, and point source generation for unresolved objects. This technique has an optimal 128x128 pixel asymmetrical field-of-view zoom. The current NZAA capability supports up to 8 objects in real-time with a near future capability of increasing to a theoretical 128 objects in real-time. JSIG performs other dynamic entity effects which are applied in vertex and fragment shaders. These effects include floating point dynamic signature application, dynamic model ablation heating models, and per-material thermal emissivity rolloff interpolated on a per-pixel zoomed window basis. JSIG additionally performs full scene per-pixel effects in a post render process. These effects include real-time convolutions, optical scene corrections, per-frame calibrations, and energy distribution blur used to compensate for projector element energy limitations.

  12. On (dynamic) range minimum queries in external memory

    DEFF Research Database (Denmark)

    Arge, L.; Fischer, Johannes; Sanders, Peter

    2013-01-01

    We study the one-dimensional range minimum query (RMQ) problem in the external memory model. We provide the first space-optimal solution to the batched static version of the problem. On an instance with N elements and Q queries, our solution takes Θ(sort(N + Q)) = Θ( N+QB log M /B N+QB ) I...

  13. Short-time dynamics in dispersions with competing short-range attraction and long-range repulsion.

    Science.gov (United States)

    Riest, Jonas; Nägele, Gerhard

    2015-12-28

    Dynamic clustering of globular Brownian particles in dispersions exhibiting competing short-range attraction and long-range repulsion (SALR) such as low-salinity protein solutions has gained a lot of interest over the past few years. While the structure of the various cluster phases has been intensely explored, little is known about the dynamics of SALR systems. We present the first systematic theoretical study of short-time diffusion and rheological transport properties of two-Yukawa potential SALR systems in the single-particle dominated dispersed-fluid phase, using semi-analytic methods where the salient hydrodynamic interactions are accounted for. We show that the dynamics has unusual features compared to reference systems with pure repulsion or attraction. Results are discussed for the hydrodynamic function characterizing short-time diffusion that reveals an intermediate-range-order (cluster) peak, self-diffusion and sedimentation coefficients, and high-frequency viscosity. As important applications, we discuss the applicability of two generalized Stokes-Einstein relations, and assess the wavenumber range required for the determination of self-diffusion in a dynamic scattering experiment.

  14. Dynamic range broadening for photomultipliers in kinetic spectrophotometry

    International Nuclear Information System (INIS)

    Rumas, V.K.

    1983-01-01

    The circuit of switching on a photomultiplier with prestage modulation developed for kinetic spectrophotometry purposes is described. Distinguishing features of the scheme are wide range of control pulse duration (40 nc - 2.5 mc) and direct transistor photostart by laser light pulse. In the case of PM prestage modulation for the second dynode modulation depth attains 400 while PM opening time constitutes 40 nc

  15. Population dynamics and range expansion in nine-banded armadillos.

    Directory of Open Access Journals (Sweden)

    William J Loughry

    Full Text Available Understanding why certain species can successfully colonize new areas while others do not is a central question in ecology. The nine-banded armadillo (Dasypus novemcinctus is a conspicuous example of a successful invader, having colonized much of the southern United States in the last 200 years. We used 15 years (1992-2006 of capture-mark-recapture data from a population of armadillos in northern Florida in order to estimate, and examine relationships among, various demographic parameters that may have contributed to this ongoing range expansion. Modeling across a range of values for γ, the probability of juveniles surviving in the population until first capture, we found that population growth rates varied from 0.80 for γ = 0.1, to 1.03 for γ = 1.0. Growth rates approached 1.0 only when γ ≥ 0.80, a situation that might not occur commonly because of the high rate of disappearance of juveniles. Net reproductive rate increased linearly with γ, but life expectancy (estimated at 3 years was independent of γ. We also found that growth rates were lower during a 3-year period of hardwood removal that removed preferred habitat than in the years preceding or following. Life-table response experiment (LTRE analysis indicated the decrease in growth rate during logging was primarily due to changes in survival rates of adults. Likewise, elasticity analyses of both deterministic and stochastic population growth rates revealed that survival parameters were more influential on population growth than were those related to reproduction. Collectively, our results are consistent with recent theories regarding biological invasions which posit that populations no longer at the leading edge of range expansion do not exhibit strong positive growth rates, and that high reproductive output is less critical in predicting the likelihood of successful invasion than are life-history strategies that emphasize allocation of resources to future, as opposed to current

  16. Dynamic range studies of the RCA streak tube in the LLL streak camera

    International Nuclear Information System (INIS)

    Thomas, S.W.; Phillips, G.E.

    1979-01-01

    As indicated by tests on several cameras, the dynamic range of the Lawrence Livermore Laboratory streak-camera system appears to be about two orders of magnitude greater than those reported for other systems for 10- to 200-ps pulses. The lack of a fine mesh grid in the RCA streak tube used in these cameras probably contributes to a lower system dynamic noise and therefore raises the dynamic range. A developmental tube with a mesh grid was tested and supports this conjecture. Order-of-magnitude variations in input slit width do not affect the spot size on the phosphor or the dynamic range of the RCA tube. (author)

  17. Probing the role of long-range interactions in the dynamics of a long-range Kitaev chain

    Science.gov (United States)

    Dutta, Anirban; Dutta, Amit

    2017-09-01

    We study the role of long-range interactions (more precisely, the long-range superconducting gap term) on the nonequilibrium dynamics considering a long-range p -wave superconducting chain in which the superconducting term decays with distance between two sites in a power-law fashion characterized by an exponent α . We show that the Kibble-Zurek scaling exponent, dictating the power-law decay of the defect density in the final state reached following a slow (in comparison to the time scale associated with the minimum gap in the spectrum of the Hamiltonian) quenching of the chemical potential μ across a quantum critical point, depends nontrivially on the exponent α as long as α 2 , we find that the exponent saturates to the corresponding well-known value of 1 /2 expected for the short-range model. Furthermore, studying the dynamical quantum phase transitions manifested in the nonanalyticities in the rate function of the return possibility I (t ) in subsequent temporal evolution following a sudden change in μ , we show the existence of a new region; in this region, we find three instants of cusp singularities in I (t ) associated with a single sector of Fisher zeros. Notably, the width of this region shrinks as α increases and vanishes in the limit α →2 , indicating that this special region is an artifact of the long-range nature of the Hamiltonian.

  18. Long-range Interactions, Stochasticity and Fractional Dynamics Dedicated to George M Zaslavsky (1935–2008)

    CERN Document Server

    Luo, Albert C J

    2011-01-01

    In memory of Dr. George Zaslavsky, "Long-range Interactions, Stochasticity and Fractional Dynamics" covers the recent developments of long-range interaction, fractional dynamics, brain dynamics and stochastic theory of turbulence, each chapter was written by established scientists in the field. The book is dedicated to Dr. George Zaslavsky, who was one of three founders of the theory of Hamiltonian chaos. The book discusses self-similarity and stochasticity and fractionality for discrete and continuous dynamical systems, as well as long-range interactions and diluted networks. A comprehensive theory for brain dynamics is also presented. In addition, the complexity and stochasticity for soliton chains and turbulence are addressed. The book is intended for researchers in the field of nonlinear dynamics in mathematics, physics and engineering. Dr. Albert C.J. Luo is a Professor at Southern Illinois University Edwardsville, USA. Dr. Valentin Afraimovich is a Professor at San Luis Potosi University, Mexico.

  19. Spatial-temporal population dynamics across species range: from centre to margin

    Science.gov (United States)

    Qinfeng Guo; Mark Taper; Michele Schoenberger; J. Brandle

    2005-01-01

    Understanding the boundaries of species'rangs and the variations in population dynamics from the centre to margin of a species' range is critical. This study simulated spatial-tamporal patterns of birth and death rates and migration across a species' range in different seasons. Our results demonstrated the importance of dispersal and migration in...

  20. How interactions between animal movement and landscape processes modify range dynamics and extinction risk

    Science.gov (United States)

    Range dynamics models now incorporate many of the mechanisms and interactions that drive species distributions. However, connectivity continues to be studied using overly simple distance-based dispersal models with little consideration of how the individual behavior of dispersin...

  1. Development of HEROICs: High-Sensitivity, High-Dynamic Range Detector Systems for Ultraviolet Astronomy Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "We propose a four-year program for the fabrication and characterization of high dynamic range, low background photon counting detectors that will support the next...

  2. Dynamic range enhancement and amplitude regeneration in single pump fibre optic parametric amplifiers using DPSK modulation

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Lorenzen, Michael Rodas; Seoane, Jorge

    2008-01-01

    Input power dynamic range enhancement and amplitude regeneration of highly distorted signals are demonstrated experimentally for 40 Gbit/s RZ-DPSK in a single-pump fibre parametric amplifier with 22 dB smallsignal gain.......Input power dynamic range enhancement and amplitude regeneration of highly distorted signals are demonstrated experimentally for 40 Gbit/s RZ-DPSK in a single-pump fibre parametric amplifier with 22 dB smallsignal gain....

  3. High Dynamic Velocity Range Particle Image Velocimetry Using Multiple Pulse Separation Imaging

    Directory of Open Access Journals (Sweden)

    Tadhg S. O’Donovan

    2010-12-01

    Full Text Available The dynamic velocity range of particle image velocimetry (PIV is determined by the maximum and minimum resolvable particle displacement. Various techniques have extended the dynamic range, however flows with a wide velocity range (e.g., impinging jets still challenge PIV algorithms. A new technique is presented to increase the dynamic velocity range by over an order of magnitude. The multiple pulse separation (MPS technique (i records series of double-frame exposures with different pulse separations, (ii processes the fields using conventional multi-grid algorithms, and (iii yields a composite velocity field with a locally optimized pulse separation. A robust criterion determines the local optimum pulse separation, accounting for correlation strength and measurement uncertainty. Validation experiments are performed in an impinging jet flow, using laser-Doppler velocimetry as reference measurement. The precision of mean flow and turbulence quantities is significantly improved compared to conventional PIV, due to the increase in dynamic range. In a wide range of applications, MPS PIV is a robust approach to increase the dynamic velocity range without restricting the vector evaluation methods.

  4. High dynamic velocity range particle image velocimetry using multiple pulse separation imaging.

    Science.gov (United States)

    Persoons, Tim; O'Donovan, Tadhg S

    2011-01-01

    The dynamic velocity range of particle image velocimetry (PIV) is determined by the maximum and minimum resolvable particle displacement. Various techniques have extended the dynamic range, however flows with a wide velocity range (e.g., impinging jets) still challenge PIV algorithms. A new technique is presented to increase the dynamic velocity range by over an order of magnitude. The multiple pulse separation (MPS) technique (i) records series of double-frame exposures with different pulse separations, (ii) processes the fields using conventional multi-grid algorithms, and (iii) yields a composite velocity field with a locally optimized pulse separation. A robust criterion determines the local optimum pulse separation, accounting for correlation strength and measurement uncertainty. Validation experiments are performed in an impinging jet flow, using laser-Doppler velocimetry as reference measurement. The precision of mean flow and turbulence quantities is significantly improved compared to conventional PIV, due to the increase in dynamic range. In a wide range of applications, MPS PIV is a robust approach to increase the dynamic velocity range without restricting the vector evaluation methods.

  5. Wide dynamic range microwave planar coupled ring resonator for sensing applications

    Science.gov (United States)

    Zarifi, Mohammad Hossein; Daneshmand, Mojgan

    2016-06-01

    A highly sensitive, microwave-coupled ring resonator with a wide dynamic range is studied for use in sensing applications. The resonator's structure has two resonant rings and, consequently, two resonant frequencies, operating at 2.3 and 2.45 GHz. Inductive and capacitive coupling mechanisms are explored and compared to study their sensing performance. Primary finite element analysis and measurement results are used to compare the capacitive and inductive coupled ring resonators, demonstrating sensitivity improvements of up to 75% and dynamic range enhancement up to 100% in the capacitive coupled structure. In this work, we are proposing capacitive coupled planar ring resonators as a wide dynamic range sensing platform for liquid sensing applications. This sensing device is well suited for low-cost, real-time low-power, and CMOS compatible sensing technologies.

  6. Sensitive high-resolution white light Schlieren technique with a large dynamic range for the investigation of ablation dynamics

    NARCIS (Netherlands)

    Vogel, Alfred; Apitz, Ingo; Freidank, Sebastian; Dijkink, R.J.

    2006-01-01

    We developed a modified Hoffman contrast technique with a 12 ns pulsed incoherent extended white-light source that enables an easily interpretable visualization of ablation plumes with high resolution, a large dynamic range, and color information. By comparison, a conventional dark-field setup with

  7. The long-term population dynamics of common wasps in their native and invaded range.

    Science.gov (United States)

    Lester, Philip J; Haywood, John; Archer, Michael E; Shortall, Chris R

    2017-03-01

    Populations of introduced species are often thought to perform differently, or experience different population dynamics, in their introduced range compared to their native habitat. Differences between habitats in climate, competition or natural enemies may result in populations with varying density dependence and population dynamics. We examined the long-term population dynamics of the invasive common wasp, Vespula vulgaris, in its native range in England and its invaded range in New Zealand. We used 39 years of wasp density data from four sites in England, and 23 years of data from six sites in New Zealand. Wasp population time series was examined using partial rate correlation functions. Gompertz population models and multivariate autoregressive state-space (MARSS) models were fitted, incorporating climatic variation. Gompertz models successfully explained 59-66% of the variation in wasp abundance between years. Density dependence in wasp populations appeared to act similarly in both the native and invaded range, with wasp abundance in the previous year as the most important variable in predicting intrinsic rate of increase (r). No evidence of cyclic population dynamics was observed. Both the Gompertz and MARSS models highlighted the role of weather conditions in each country as significant predictors of annual wasp abundance. The temporal evolution of wasp populations at all sites was best modelled jointly using a single latent dynamic factor for local trends, with the inclusion of a latent spring weather covariate. That same parsimonious multivariate model structure was optimal in both the native and invaded range. Density dependence is overwhelmingly important in predicting wasp densities and 'wasp years' in both the native and invaded range. Spring weather conditions in both countries have a major influence, probably through their impact on wasp colony initiation and early development. The population dynamics in the native range and invaded range show no

  8. Detail enhancement for high-dynamic-range infrared images based on guided image filter

    Science.gov (United States)

    Liu, Ning; Zhao, Dongxue

    2014-11-01

    Detail enhancement and noise reduction play crucial roles in high dynamic range infrared image processing. The main focuses are to compress the high dynamic range images with an effective way to display on lower dynamic range monitors, enhance the perceptibility of small details, and reduce the noises without causing artifacts. In this paper, we propose a new method for detail enhancement and noise reduction of high dynamic range infrared images. We first apply a guided image filter to smooth the input image and separate the image into the base component and the detail component. This process also gives us an adaptive weighting coefficient associated with the details generated by the filter kernel. After the filtering process, we compress the base component into the display range by our modified histogram projection and enhance the detail component using the gain mask of the filter weighting coefficient. At last, we recombine the two parts and quantize the result to 8-bit domain. Our method is significantly better than those based on histogram equalization (HE), and it also has better visual effect than bilateral filter-based methods. Furthermore, our proposed method is much faster, non-approximate and suffers much less gradient flipping artifacts compared to the bilateral filter-based methods because the guided image filter uses the local linear model. We demonstrate that our method is both effective and efficient in a great variety of applications. Experimental verification and detailed analysis are shown in this paper.

  9. Feasible Muscle Activation Ranges Based on Inverse Dynamics Analyses of Human Walking

    Science.gov (United States)

    Simpson, Cole S.; Sohn, M. Hongchul; Allen, Jessica L.; Ting, Lena H.

    2015-01-01

    Although it is possible to produce the same movement using an infinite number of different muscle activation patterns owing to musculoskeletal redundancy, the degree to which observed variations in muscle activity can deviate from optimal solutions computed from biomechanical models is not known. Here, we examined the range of biomechanically permitted activation levels in individual muscles during human walking using a detailed musculoskeletal model and experimentally-measured kinetics and kinematics. Feasible muscle activation ranges define the minimum and maximum possible level of each muscle’s activation that satisfy inverse dynamics joint torques assuming that all other muscles can vary their activation as needed. During walking, 73% of the muscles had feasible muscle activation ranges that were greater than 95% of the total muscle activation range over more than 95% of the gait cycle, indicating that, individually, most muscles could be fully active or fully inactive while still satisfying inverse dynamics joint torques. Moreover, the shapes of the feasible muscle activation ranges did not resemble previously-reported muscle activation patterns nor optimal solutions, i.e. static optimization and computed muscle control, that are based on the same biomechanical constraints. Our results demonstrate that joint torque requirements from standard inverse dynamics calculations are insufficient to define the activation of individual muscles during walking in healthy individuals. Identifying feasible muscle activation ranges may be an effective way to evaluate the impact of additional biomechanical and/or neural constraints on possible versus actual muscle activity in both normal and impaired movements. PMID:26300401

  10. Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems

    International Nuclear Information System (INIS)

    Yang, Ge; Wang, Jun; Fang, Wen

    2015-01-01

    In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems

  11. Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems.

    Science.gov (United States)

    Yang, Ge; Wang, Jun; Fang, Wen

    2015-04-01

    In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems.

  12. Fractional quantum mechanics on networks: Long-range dynamics and quantum transport.

    Science.gov (United States)

    Riascos, A P; Mateos, José L

    2015-11-01

    In this paper we study the quantum transport on networks with a temporal evolution governed by the fractional Schrödinger equation. We generalize the dynamics based on continuous-time quantum walks, with transitions to nearest neighbors on the network, to the fractional case that allows long-range displacements. By using the fractional Laplacian matrix of a network, we establish a formalism that combines a long-range dynamics with the quantum superposition of states; this general approach applies to any type of connected undirected networks, including regular, random, and complex networks, and can be implemented from the spectral properties of the Laplacian matrix. We study the fractional dynamics and its capacity to explore the network by means of the transition probability, the average probability of return, and global quantities that characterize the efficiency of this quantum process. As a particular case, we explore analytically these quantities for circulant networks such as rings, interacting cycles, and complete graphs.

  13. A low-power high dynamic range front-end ASIC for imaging calorimeters

    CERN Document Server

    Bagliesi, M G; Marrocchesi, P S; Meucci, M; Millucci, V; Morsani, F; Paoletti, R; Pilo, F; Scribano, A; Turini, N; Valle, G D

    2002-01-01

    High granularity calorimeters with shower imaging capabilities require dedicated front-end electronics. The ICON 4CH and VA4 PMT chip-set is suitable for very high dynamic range systems with strict noise requirements. The ICON 4CH is a 4 channel input, 12 channel output ASIC designed for use in a multi-anode photomultiplier system with very large dynamic range and low-noise requirements. Each of the four input signals to the ASIC is split equally into three branches by a current conveyor. Each of the three branches is scaled differently: 1:1, 1:8 and 1:80. The signal is read out by a 12 channel low noise/low power high dynamic range charge sensitive preamplifier-shaper circuit (VA4-PMT chip), with simultaneous sample- and-hold, multiplexed analog read-out, calibration facilities. Tests performed in our lab with a PMT are reported in terms of linearity, dynamic range and cross-talk of the system. (5 refs).

  14. On cluster ions, ion transmission, and linear dynamic range limitations in electrospray (ionspray) mass spectrometry

    NARCIS (Netherlands)

    Zook, D.R; Bruins, A.P.

    The ion transmission in Electrospray (Ionspray) Mass Spectrometry (ESMS) was studied in order to examine the instrumental factors potentially contributing to observed ESMS linear dynamic range (LDR) limitations. A variety of means used for the investigation of ion transmission demonstrated that a

  15. What controls the population dynamics of the invasive thistle Carduus nutans in its native range?

    NARCIS (Netherlands)

    Jongejans, E.; Sheppard, A.W.; Shea, K.

    2006-01-01

    1. The invasive thistle Carduus nutans causes major economic losses in the Americas, Australia and New Zealand. For the first time, we have modelled its population dynamics in its native range, Eurasia, where it rarely reaches problematic densities, in order to identify ways to improve management

  16. Quantum dot SOA input power dynamic range improvement for differential-phase encoded signals.

    Science.gov (United States)

    Vallaitis, T; Bonk, R; Guetlein, J; Hillerkuss, D; Li, J; Brenot, R; Lelarge, F; Duan, G H; Freude, W; Leuthold, J

    2010-03-15

    Experimentally we find a 10 dB input power dynamic range advantage for amplification of phase encoded signals with quantum dot SOA as compared to low-confinement bulk SOA. An analysis of amplitude and phase effects shows that this improvement can be attributed to the lower alpha-factor found in QD SOA.

  17. Monte Carlo simulation of particle interactions at high dynamic range : Advancing beyond the googol

    NARCIS (Netherlands)

    Ormel, C. W.; Spaans, M.

    2008-01-01

    We present a method which extends Monte Carlo studies to situations that require a large dynamic range in particle number. The underlying idea is that, in order to calculate the collisional evolution of a system, some particle interactions are more important than others and require more resolution,

  18. A Hybrid Shared-Memory Parallel Max-Tree Algorithm for Extreme Dynamic-Range Images

    NARCIS (Netherlands)

    Moschini, Ugo; Meijster, Arnold; Wilkinson, Michael

    Max-trees, or component trees, are graph structures that represent the connected components of an image in a hierarchical way. Nowadays, many application fields rely on images with high-dynamic range or floating point values. Efficient sequential algorithms exist to build trees and compute

  19. Lithium-ion battery dynamic model for wide range of operating conditions

    DEFF Research Database (Denmark)

    Stroe, Ana-Irina; Stroe, Daniel-Ioan; Swierczynski, Maciej Jozef

    2017-01-01

    characterization tests performed for a wide range of operating conditions (temperature, load current and state-of-charge) on a commercial available 13Ah high-power lithium titanate oxide battery cell. The obtained results were used to parametrize the proposed dynamic model of the battery cell. To assess...

  20. Density matrix renormalization group with efficient dynamical electron correlation through range separation

    DEFF Research Database (Denmark)

    Hedegård, Erik D.; Knecht, Stefan; Kielberg, Jesper Skau

    2015-01-01

    We present a new hybrid multiconfigurational method based on the concept of range-separation that combines the density matrix renormalization group approach with density functional theory. This new method is designed for the simultaneous description of dynamical and static electroncorrelation...... effects in multiconfigurational electronic structure problems....

  1. High Dynamic Range X-Ray Detector Pixel Architectures Utilizing Charge Removal

    Science.gov (United States)

    Weiss, Joel T.; Shanks, Katherine S.; Philipp, Hugh T.; Becker, Julian; Chamberlain, Darol; Purohit, Prafull; Tate, Mark W.; Gruner, Sol M.

    2017-04-01

    Several charge integrating CMOS pixel front ends utilizing charge removal techniques have been fabricated to extend dynamic range for X-ray diffraction applications at synchrotron sourcesand X-ray free electron lasers (XFELs). The pixels described herein build on the mixed mode pixel array detector (MM-PAD) framework, developed previously by our group to perform high dynamic range imaging. These new pixels boast several orders of magnitude improvement in maximum flux over the MM-PAD, which is capable of measuring a sustained flux in excess of 108 X-rays/pixel/s while maintaining sensitivity to smaller signals, down to single X-rays. To extend dynamic range, charge is removed from the integration node of the frontend amplifier without interrupting integration. The number of times this process occurs is recorded by a digital counter in the pixel. The parameter limiting full well is, thereby, shifted from the size of an integration capacitor to the depth of a digital counter. The result is similar to that achieved by counting pixel array detectors, but the integrators presented here are designed to tolerate a sustained flux > 1011 X-rays/pixel/s. Pixel front-end linearity was evaluated by direct current injection and results are presented. A small-scale readout ASIC utilizing these pixel architectures has been fabricated and the use of these architectures to increase single X-ray pulse dynamic range at XFELs is discussed briefly.

  2. High dynamic range isotope ratio measurements using an analog electron multiplier

    Czech Academy of Sciences Publication Activity Database

    Williams, P.; Lorinčík, Jan; Franzreb, K.; Herwig, R.

    2013-01-01

    Roč. 45, č. 1 (2013), s. 549-552 ISSN 0142-2421 R&D Projects: GA MŠk ME 894 Institutional support: RVO:67985882 Keywords : Isotope ratios * electron multiplier * dynamic range Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.393, year: 2013

  3. Uncertainty in predicting range dynamics of endemic alpine plants under climate warming.

    Science.gov (United States)

    Hülber, Karl; Wessely, Johannes; Gattringer, Andreas; Moser, Dietmar; Kuttner, Michael; Essl, Franz; Leitner, Michael; Winkler, Manuela; Ertl, Siegrun; Willner, Wolfgang; Kleinbauer, Ingrid; Sauberer, Norbert; Mang, Thomas; Zimmermann, Niklaus E; Dullinger, Stefan

    2016-07-01

    Correlative species distribution models have long been the predominant approach to predict species' range responses to climate change. Recently, the use of dynamic models is increasingly advocated for because these models better represent the main processes involved in range shifts and also simulate transient dynamics. A well-known problem with the application of these models is the lack of data for estimating necessary parameters of demographic and dispersal processes. However, what has been hardly considered so far is the fact that simulating transient dynamics potentially implies additional uncertainty arising from our ignorance of short-term climate variability in future climatic trends. Here, we use endemic mountain plants of Austria as a case study to assess how the integration of decadal variability in future climate affects outcomes of dynamic range models as compared to projected long-term trends and uncertainty in demographic and dispersal parameters. We do so by contrasting simulations of a so-called hybrid model run under fluctuating climatic conditions with those based on a linear interpolation of climatic conditions between current values and those predicted for the end of the 21st century. We find that accounting for short-term climate variability modifies model results nearly as differences in projected long-term trends and much more than uncertainty in demographic/dispersal parameters. In particular, range loss and extinction rates are much higher when simulations are run under fluctuating conditions. These results highlight the importance of considering the appropriate temporal resolution when parameterizing and applying range-dynamic models, and hybrid models in particular. In case of our endemic mountain plants, we hypothesize that smoothed linear time series deliver more reliable results because these long-lived species are primarily responsive to long-term climate averages. © 2016 John Wiley & Sons Ltd.

  4. Dual-exposure technique for extending the dynamic range of x-ray flat panel detectors.

    Science.gov (United States)

    Sisniega, A; Abella, M; Desco, M; Vaquero, J J

    2014-01-20

    This work presents an approach to extend the dynamic range of x-ray flat panel detectors by combining two acquisitions of the same sample taken with two different x-ray photon flux levels and the same beam spectral configuration. In order to combine both datasets, the response of detector pixels was modelled in terms of mean and variance using a linear model. The model was extended to take into account the effect of pixel saturation. We estimated a joint probability density function (j-pdf) of the pixel values by assuming that each dataset follows an independent Gaussian distribution. This j-pdf was used for estimating the final pixel value of the high-dynamic-range dataset using a maximum likelihood method. The suitability of the pixel model for the representation of the detector signal was assessed using experimental data from a small-animal cone-beam micro-CT scanner equipped with a flat panel detector. The potential extension in dynamic range offered by our method was investigated for generic flat panel detectors using analytical expressions and simulations. The performance of the proposed dual-exposure approach in realistic imaging environments was compared with that of a regular single-exposure technique using experimental data from two different phantoms. Image quality was assessed in terms of signal-to-noise ratio, contrast, and analysis of profiles drawn on the images. The dynamic range, measured as the ratio between the exposure for saturation and the exposure equivalent to instrumentation noise, was increased from 76.9 to 166.7 when using our method. Dual-exposure results showed higher contrast-to-noise ratio and contrast resolution than the single-exposure acquisitions for the same x-ray dose. In addition, image artifacts were reduced in the combined dataset. This technique to extend the dynamic range of the detector without increasing the dose is particularly suited to image samples that contain both low and high attenuation regions.

  5. Determining the dynamic range of MCPs based on pore size and strip current

    Science.gov (United States)

    Hunt, C.; Adrian, M. L.; Herrero, F.; James, P.; Jones, H. H.; Rodriguez, M.; Roman, P.; Shappirio, M.

    2010-12-01

    Micro-Channel Plates (MCPs) are used as detectors for almost all detectors measuring particles (both ions, electrons and neutrals) below 30 keV. Recent advances in the manufacturing technology of the MCPs have increased the number of options one has when selecting plates for an instrument. But it is not clear how many of these options affect the performance of the MCPs. In particular the dynamic range is not a clear cut calculation to make from the strip current. There is also some evidence that pore size and coating play a role. We measured the dynamic range and pulse height distribution of MCPs detector chevron stacks with a wide variety of strip currents from the low “normal” range in the EDR range. We also looked at the effects of varying the pore size from 25 microns to 10 microns, partial plating of the MCP surface and coating one surface on each MCP with gold rather than the standard zinc chromium. We will show how the dynamic range and pulse height distributions vary vs. strip current, pore size, and surface plating configurations.

  6. A Miniaturized Escherichia coli Green Light Sensor with High Dynamic Range.

    Science.gov (United States)

    Ong, Nicholas T; Tabor, Jeffrey J

    2018-02-08

    Genetically engineered photoreceptors enable unrivaled control over gene expression. Previously, we ported the Synechocystis PCC 6803 CcaSR two-component system, which is activated by green light and deactivated by red, into Escherichia coli, resulting in a sensor with a sixfold dynamic range. Later, we optimized pathway protein expression levels and the output promoter sequence to decrease transcriptional leakiness and to increase the dynamic range to approximately 120-fold. These CcaSR v 1.0 and v 2.0 systems have been used for precise quantitative, temporal, and spatial control of gene expression for a variety of applications. Recently, other workers deleted two PAS domains of unknown function from the CcaS sensor histidine kinase in a system similar to CcaSR v 1.0. Here we apply these deletions to CcaSR v 2.0, resulting in a v 3.0 light sensor with an output four times less leaky and a dynamic range of nearly 600-fold. We demonstrate that the PAS domain deletions have no deleterious effect on CcaSR green light sensitivity or response dynamics. CcaSR v 3.0 is the best-performing engineered bacterial green light sensor available, and should have broad applications in fundamental and synthetic biology studies. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Coupled range dynamics of brood parasites and their hosts responding to climate and vegetation changes.

    Science.gov (United States)

    Péron, Guillaume; Altwegg, Res; Jamie, Gabriel A; Spottiswoode, Claire N

    2016-09-01

    As populations shift their ranges in response to global change, local species assemblages can change, setting the stage for new ecological interactions, community equilibria and evolutionary responses. Here, we focus on the range dynamics of four avian brood parasite species and their hosts in southern Africa, in a context of bush encroachment (increase in woody vegetation density in places previously occupied by savanna-grassland mosaics) favouring some species at the expense of others. We first tested whether hosts and parasites constrained each other's ability to expand or maintain their ranges. Secondly, we investigated whether range shifts represented an opportunity for new host-parasite and parasite-parasite interactions. We used multispecies dynamic occupancy models with interactions, fitted to citizen science data, to estimate the contribution of interspecific interactions to range shifts and to quantify the change in species co-occurrence probability over a 25-year period. Parasites were able to track their hosts' range shifts. We detected no deleterious effect of the parasites' presence on either the local population viability of host species or the hosts' ability to colonize newly suitable areas. In the recently diversified indigobird radiation (Vidua spp.), following bush encroachment, the new assemblages presented more potential opportunities for speciation via host switch, but also more potential for hybridization between extant lineages, also via host switch. Multispecies dynamic occupancy models with interactions brought new insights into the feedbacks between range shifts, biotic interactions and local demography: brood parasitism had little detected impact on extinction or colonization processes, but inversely the latter processes affected biotic interactions via the modification of co-occurrence patterns. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

  8. Preference limits of the visual dynamic range for ultra high quality and aesthetic conveyance

    Science.gov (United States)

    Daly, Scott; Kunkel, Timo; Sun, Xing; Farrell, Suzanne; Crum, Poppy

    2013-03-01

    A subjective study was conducted to investigate the preferred maximum and minimum display luminances in order to determine the dynamic ranges for future displays. Two studies address the diffuse reflective regions, and a third study tested preferences of highlight regions. Preferences, as opposed to detection thresholds, were studied to provide results more directly relevant to the viewing of entertainment or art. Test images were specifically designed to test these limits without the perceptual conflicts that usually occur in these types of studies. For the diffuse range, we found a display with a dynamic range having luminances between 0.1 and 650 cd/m2 matches the average preferences. However, to satisfy 90% of the population, a dynamic range from 0.005 and ~3,000 cd/m2 is needed. Since a display should be able to produce values brighter than the diffuse white maximum, as in specular highlights and emissive sources, the highlight study concludes that even the average preferred maximum luminance for highlight reproduction is ~4,000 cd/m2.

  9. Wavepacket dynamics in one-dimensional system with long-range correlated disorder

    Science.gov (United States)

    Yamada, Hiroaki S.

    2018-03-01

    We numerically investigate dynamical property in the one-dimensional tight-binding model with long-range correlated disorder having power spectrum 1 /fα (α: spectrum exponent) generated by Fourier filtering method. For relatively small α MSD) of the initially localized wavepacket shows ballistic spread and localizes as time elapses. It is shown that α-dependence of the dynamical localization length determined by the MSD exhibits a simple scaling law in the localization regime for the relatively weak disorder strength W. Furthermore, scaled MSD by the dynamical localization length almost obeys an universal function from the ballistic to the localization regime in the various combinations of the parameters α and W.

  10. Territorial dynamics and stable home range formation for central place foragers.

    Directory of Open Access Journals (Sweden)

    Jonathan R Potts

    Full Text Available Uncovering the mechanisms behind territory formation is a fundamental problem in behavioural ecology. The broad nature of the underlying conspecific avoidance processes are well documented across a wide range of taxa. Scent marking in particular is common to a large range of terrestrial mammals and is known to be fundamental for communication. However, despite its importance, exact quantification of the time-scales over which scent cues and messages persist remains elusive. Recent work by the present authors has begun to shed light on this problem by modelling animals as random walkers with scent-mediated interaction processes. Territories emerge as dynamic objects that continually change shape and slowly move without settling to a fixed location. As a consequence, the utilisation distribution of such an animal results in a slowly increasing home range, as shown for urban foxes (Vulpes vulpes. For certain other species, however, home ranges reach a stable state. The present work shows that stable home ranges arise when, in addition to scent-mediated conspecific avoidance, each animal moves as a central place forager. That is, the animal's movement has a random aspect but is also biased towards a fixed location, such as a den or nest site. Dynamic territories emerge but the probability distribution of the territory border locations reaches a steady state, causing stable home ranges to emerge from the territorial dynamics. Approximate analytic expressions for the animal's probability density function are derived. A programme is given for using these expressions to quantify both the strength of the animal's movement bias towards the central place and the time-scale over which scent messages persist. Comparisons are made with previous theoretical work modelling central place foragers with conspecific avoidance. Some insights into the mechanisms behind allometric scaling laws of animal space use are also given.

  11. The CAOS camera platform: ushering in a paradigm change in extreme dynamic range imager design

    Science.gov (United States)

    Riza, Nabeel A.

    2017-02-01

    Multi-pixel imaging devices such as CCD, CMOS and Focal Plane Array (FPA) photo-sensors dominate the imaging world. These Photo-Detector Array (PDA) devices certainly have their merits including increasingly high pixel counts and shrinking pixel sizes, nevertheless, they are also being hampered by limitations in instantaneous dynamic range, inter-pixel crosstalk, quantum full well capacity, signal-to-noise ratio, sensitivity, spectral flexibility, and in some cases, imager response time. Recently invented is the Coded Access Optical Sensor (CAOS) Camera platform that works in unison with current Photo-Detector Array (PDA) technology to counter fundamental limitations of PDA-based imagers while providing high enough imaging spatial resolution and pixel counts. Using for example the Texas Instruments (TI) Digital Micromirror Device (DMD) to engineer the CAOS camera platform, ushered in is a paradigm change in advanced imager design, particularly for extreme dynamic range applications.

  12. 32-channel pyrometer with high dynamic range for studies of shocked nanothermites

    Science.gov (United States)

    Bassett, Will P.; Dlott, Dana D.

    2017-01-01

    A 32-channel optical pyrometer has been developed for studying temperature dynamics of shock-initiated reactive materials with one nanosecond time resolution and high dynamic range. The pyrometer consists of a prism spectrograph which directs the spectrally-resolved emission to 32 fiber optics and 32 photomultiplier tubes and digitizers. Preliminary results show shock-initiated reactions of a nanothermite composite, nano CuO/Al in nitrocellulose binder, consists of three stages. The first stage occurred at 30 ns, right after the shock unloaded, the second stage at 100 ns and the third at 1 μs, and the temperatures ranged from 2100K to 3000K. Time-resolved emission spectra suggest hot spots formed during shock unloading, which initiated the bulk thermite/nitrocellulose reaction.

  13. A high sensitive 66 dB linear dynamic range receiver for 3-D laser radar

    Science.gov (United States)

    Ma, Rui; Zheng, Hao; Zhu, Zhangming

    2017-08-01

    This study presents a CMOS receiver chip realized in 0.18 μm standard CMOS technology and intended for high precision 3-D laser radar. The chip includes an adjustable gain transimpedance pre-amplifier, a post-amplifier and two timing comparators. An additional feedback is employed in the regulated cascode transimpedance amplifier to decrease the input impedance, and a variable gain transimpedance amplifier controlled by digital switches and analog multiplexer is utilized to realize four gain modes, extending the input dynamic range. The measurement shows that the highest transimpedance of the channel is 50 k {{Ω }}, the uncompensated walk error is 1.44 ns in a wide linear dynamic range of 66 dB (1:2000), and the input referred noise current is 2.3 pA/\\sqrt{{Hz}} (rms), resulting in a very low detectable input current of 1 μA with SNR = 5.

  14. A highly sensitive RF-to-DC power converter with an extended dynamic range

    KAUST Repository

    Almansouri, Abdullah Saud Mohammed

    2017-10-24

    This paper proposes a highly sensitive RF-to-DC power converter with an extended dynamic range that is designed to operate at the medical band 433 MHz and simulated using 0.18 μm CMOS technology. Compared to the conventional fully cross-coupled rectifier, the proposed design offers 3.2× the dynamic range. It is also highly sensitive and requires −18 dBm of input power to produce a 1 V-output voltage when operating with a 100 kΩ load. Furthermore, the proposed design offers an open circuit sensitivity of −23.4 dBm and a peak power conversion efficiency of 67%.

  15. Dynamical phase diagram of quantum spin chains with long-range interactions

    Science.gov (United States)

    Halimeh, Jad C.; Zauner-Stauber, Valentin

    2017-10-01

    Using an infinite matrix product state (iMPS) technique based on the time-dependent variational principle (TDVP), we study two major types of dynamical phase transitions (DPT) in the one-dimensional transverse-field Ising model (TFIM) with long-range power-law (∝1 /rα with r interspin distance) interactions out of equilibrium in the thermodynamic limit—DPT-I: based on an order parameter in a (quasi-)steady state, and DPT-II: based on nonanalyticities (cusps) in the Loschmidt-echo return rate. We construct the corresponding rich dynamical phase diagram, while considering different quench initial conditions. We find a nontrivial connection between both types of DPT based on their critical lines. Moreover, and very interestingly, we detect a new DPT-II dynamical phase in a certain range of interaction exponent α , characterized by what we call anomalous cusps that are distinct from the regular cusps usually associated with DPT-II. Our results provide the characterization of experimentally accessible signatures of the dynamical phases studied in this work.

  16. Dynamic Gesture Recognition with a Terahertz Radar Based on Range Profile Sequences and Doppler Signatures.

    Science.gov (United States)

    Zhou, Zhi; Cao, Zongjie; Pi, Yiming

    2017-12-21

    The frequency of terahertz radar ranges from 0.1 THz to 10 THz, which is higher than that of microwaves. Multi-modal signals, including high-resolution range profile (HRRP) and Doppler signatures, can be acquired by the terahertz radar system. These two kinds of information are commonly used in automatic target recognition; however, dynamic gesture recognition is rarely discussed in the terahertz regime. In this paper, a dynamic gesture recognition system using a terahertz radar is proposed, based on multi-modal signals. The HRRP sequences and Doppler signatures were first achieved from the radar echoes. Considering the electromagnetic scattering characteristics, a feature extraction model is designed using location parameter estimation of scattering centers. Dynamic Time Warping (DTW) extended to multi-modal signals is used to accomplish the classifications. Ten types of gesture signals, collected from a terahertz radar, are applied to validate the analysis and the recognition system. The results of the experiment indicate that the recognition rate reaches more than 91%. This research verifies the potential applications of dynamic gesture recognition using a terahertz radar.

  17. Dynamic range of frontoparietal functional modulation is associated with working memory capacity limitations in older adults.

    Science.gov (United States)

    Hakun, Jonathan G; Johnson, Nathan F

    2017-11-01

    Older adults tend to over-activate regions throughout frontoparietal cortices and exhibit a reduced range of functional modulation during WM task performance compared to younger adults. While recent evidence suggests that reduced functional modulation is associated with poorer task performance, it remains unclear whether reduced range of modulation is indicative of general WM capacity-limitations. In the current study, we examined whether the range of functional modulation observed over multiple levels of WM task difficulty (N-Back) predicts in-scanner task performance and out-of-scanner psychometric estimates of WM capacity. Within our sample (60-77years of age), age was negatively associated with frontoparietal modulation range. Individuals with greater modulation range exhibited more accurate N-Back performance. In addition, despite a lack of significant relationships between N-Back and complex span task performance, range of frontoparietal modulation during the N-Back significantly predicted domain-general estimates of WM capacity. Consistent with previous cross-sectional findings, older individuals with less modulation range exhibited greater activation at the lowest level of task difficulty but less activation at the highest levels of task difficulty. Our results are largely consistent with existing theories of neurocognitive aging (e.g. CRUNCH) but focus attention on dynamic range of functional modulation asa novel marker of WM capacity-limitations in older adults. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Low Parametric Sensitivity Realizations with relaxed L2-dynamic-range-scaling constraints

    OpenAIRE

    Hilaire , Thibault

    2009-01-01

    This paper presents a new dynamic-range scaling for the implementation of filters/controllers in state-space form. Relaxing the classical L2-scaling constraints by specific fixed-point considerations allows for a higher degree of freedom for the optimal L2-parametric sensitivity problem. However, overflows in the implementation are still prevented. The underlying constrained problem is converted into an unconstrained problem for which a solution can be provided. This leads to realizations whi...

  19. Dynamics of wood in stream networks of the western Cascades Range, Oregon

    Science.gov (United States)

    Nicole M. Czarnomski; David M. Dreher; Kai U. Snyder; Julia A. Jones; Frederick J. Swanson

    2008-01-01

    We develop and test a conceptual model of wood dynamics in stream networks that considers legacies of forest management practices, floods, and debris flows. We combine an observational study of wood in 25 km of 2nd- through 5th-order streams in a steep, forested watershed of the western Cascade Range of Oregon with whole-network studies of forest cutting, roads, and...

  20. A High Dynamic-Range Beam Position Measurement System for ELSA-2

    CERN Document Server

    Balleyguier, P; Guimbal, P; Borrion, H

    2003-01-01

    New beamlines are presently under construction for ELSA, a 20 MeV electron linac located at Bruyères-le-Châtel. These lines need a beam position measurement system filling the following requirements: small footprint, wide dynamic range, single-bunch/multi-bunch capability, simple design. We designed a compact 4-stripline sensor and an electronic treatment chain based on logarithmic amplifiers. This paper presents the design, cold and hot test results.

  1. Dynamic Range Enhancement of High-Speed Electrical Signal Data via Non-Linear Compression

    Science.gov (United States)

    Laun, Matthew C. (Inventor)

    2016-01-01

    Systems and methods for high-speed compression of dynamic electrical signal waveforms to extend the measuring capabilities of conventional measuring devices such as oscilloscopes and high-speed data acquisition systems are discussed. Transfer function components and algorithmic transfer functions can be used to accurately measure signals that are within the frequency bandwidth but beyond the voltage range and voltage resolution capabilities of the measuring device.

  2. Forward and backward tone mapping of high dynamic range images based on subband architecture

    Science.gov (United States)

    Bouzidi, Ines; Ouled Zaid, Azza

    2015-01-01

    This paper presents a novel High Dynamic Range (HDR) tone mapping (TM) system based on sub-band architecture. Standard wavelet filters of Daubechies, Symlets, Coiflets and Biorthogonal were used to estimate the proposed system performance in terms of Low Dynamic Range (LDR) image quality and reconstructed HDR image fidelity. During TM stage, the HDR image is firstly decomposed in sub-bands using symmetrical analysis-synthesis filter bank. The transform coefficients are then rescaled using a predefined gain map. The inverse Tone Mapping (iTM) stage is straightforward. Indeed, the LDR image passes through the same sub-band architecture. But, instead of reducing the dynamic range, the LDR content is boosted to an HDR representation. Moreover, in our TM sheme, we included an optimization module to select the gain map components that minimize the reconstruction error, and consequently resulting in high fidelity HDR content. Comparisons with recent state-of-the-art methods have shown that our method provides better results in terms of visual quality and HDR reconstruction fidelity using objective and subjective evaluations.

  3. Seasonal source-sink dynamics at the edge of a species' range.

    Science.gov (United States)

    Kanda, L Leann; Fuller, Todd K; Sievert, Paul R; Kellogg, Robert L

    2009-06-01

    The roles of dispersal and population dynamics in determining species' range boundaries recently have received theoretical attention but little empirical work. Here we provide data on survival, reproduction, and movement for a Virginia opossum (Didelphis virginiana) population at a local distributional edge in central Massachusetts (USA). Most juvenile females that apparently exploited anthropogenic resources survived their first winter, whereas those using adjacent natural resources died of starvation. In spring, adult females recolonized natural areas. A life-table model suggests that a population exploiting anthropogenic resources may grow, acting as source to a geographically interlaced sink of opossums using only natural resources, and also providing emigrants for further range expansion to new human-dominated landscapes. In a geographical model, this source-sink dynamic is consistent with the local distribution identified through road-kill surveys. The Virginia opossum's exploitation of human resources likely ameliorates energetically restrictive winters and may explain both their local distribution and their northward expansion in unsuitable natural climatic regimes. Landscape heterogeneity, such as created by urbanization, may result in source-sink dynamics at highly localized scales. Differential fitness and individual dispersal movements within local populations are key to generating regional distributions, and thus species ranges, that exceed expectations.

  4. The high dynamic range pixel array detector (HDR-PAD): Concept and design

    Energy Technology Data Exchange (ETDEWEB)

    Shanks, Katherine S.; Philipp, Hugh T.; Weiss, Joel T.; Becker, Julian; Tate, Mark W. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M., E-mail: smg26@cornell.edu [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

    2016-07-27

    Experiments at storage ring light sources as well as at next-generation light sources increasingly require detectors capable of high dynamic range operation, combining low-noise detection of single photons with large pixel well depth. XFEL sources in particular provide pulse intensities sufficiently high that a purely photon-counting approach is impractical. The High Dynamic Range Pixel Array Detector (HDR-PAD) project aims to provide a dynamic range extending from single-photon sensitivity to 10{sup 6} photons/pixel in a single XFEL pulse while maintaining the ability to tolerate a sustained flux of 10{sup 11} ph/s/pixel at a storage ring source. Achieving these goals involves the development of fast pixel front-end electronics as well as, in the XFEL case, leveraging the delayed charge collection due to plasma effects in the sensor. A first prototype of essential electronic components of the HDR-PAD readout ASIC, exploring different options for the pixel front-end, has been fabricated. Here, the HDR-PAD concept and preliminary design will be described.

  5. Multi-exposure high dynamic range image synthesis with camera shake correction

    Science.gov (United States)

    Li, Xudong; Chen, Yongfu; Jiang, Hongzhi; Zhao, Huijie

    2017-10-01

    Machine vision plays an important part in industrial online inspection. Owing to the nonuniform illuminance conditions and variable working distances, the captured image tends to be over-exposed or under-exposed. As a result, when processing the image such as crack inspection, the algorithm complexity and computing time increase. Multiexposure high dynamic range (HDR) image synthesis is used to improve the quality of the captured image, whose dynamic range is limited. Inevitably, camera shake will result in ghost effect, which blurs the synthesis image to some extent. However, existed exposure fusion algorithms assume that the input images are either perfectly aligned or captured in the same scene. These assumptions limit the application. At present, widely used registration based on Scale Invariant Feature Transform (SIFT) is usually time consuming. In order to rapidly obtain a high quality HDR image without ghost effect, we come up with an efficient Low Dynamic Range (LDR) images capturing approach and propose a registration method based on ORiented Brief (ORB) and histogram equalization which can eliminate the illumination differences between the LDR images. The fusion is performed after alignment. The experiment results demonstrate that the proposed method is robust to illumination changes and local geometric distortion. Comparing with other exposure fusion methods, our method is more efficient and can produce HDR images without ghost effect by registering and fusing four multi-exposure images.

  6. Hybrid infrared scene projector (HIRSP): a high dynamic range infrared scene projector, part II

    Science.gov (United States)

    Cantey, Thomas M.; Bowden, Mark; Cosby, David; Ballard, Gary

    2008-04-01

    This paper is a continuation of the merging of two dynamic infrared scene projector technologies to provide a unique and innovative solution for the simulation of high dynamic temperature ranges for testing infrared imaging sensors. This paper will present some of the challenges and performance issues encountered in implementing this unique projector system into a Hardware-in-the-Loop (HWIL) simulation facility. The projection system combines the technologies of a Honeywell BRITE II extended voltage range emissive resistor array device and an optically scanned laser diode array projector (LDAP). The high apparent temperature simulations are produced from the luminescent infrared radiation emitted by the high power laser diodes. The hybrid infrared projector system is being integrated into an existing HWIL simulation facility and is used to provide real-world high radiance imagery to an imaging infrared unit under test. The performance and operation of the projector is presented demonstrating the merit and success of the hybrid approach. The high dynamic range capability simulates a 250 Kelvin apparent background temperature to 850 Kelvin maximum apparent temperature signatures. This is a large increase in radiance projection over current infrared scene projection capabilities.

  7. Seasonal source-sink dynamics at the edge of a species' range

    Science.gov (United States)

    Kanda, L.L.; Fuller, T.K.; Sievert, P.R.; Kellogg, R.L.

    2009-01-01

    The roles of dispersal and population dynamics in determining species' range boundaries recently have received theoretical attention but little empirical work. Here we provide data on survival, reproduction, and movement for a Virginia opossum (Didelphis virginiana) population at a local distributional edge in central Massachusetts (USA). Most juvenile females that apparently exploited anthropogenic resources survived their first winter, whereas those using adjacent natural resources died of starvation. In spring, adult females recolonized natural areas. A life-table model suggests that a population exploiting anthropogenic resources may grow, acting as source to a geographically interlaced sink of opossums using only natural resources, and also providing emigrants for further range expansion to new human-dominated landscapes. In a geographical model, this source-sink dynamic is consistent with the local distribution identified through road-kill surveys. The Virginia opossum's exploitation of human resources likely ameliorates energetically restrictive winters and may explain both their local distribution and their northward expansion in unsuitable natural climatic regimes. Landscape heterogeneity, such as created by urbanization, may result in source-sink dynamics at highly localized scales. Differential fitness and individual dispersal movements within local populations are key to generating regional distributions, and thus species ranges, that exceed expectations. ?? 2009 by the Ecological Society of America.

  8. A new high dynamic range ROIC with smart light intensity control unit

    Science.gov (United States)

    Yazici, Melik; Ceylan, Omer; Shafique, Atia; Abbasi, Shahbaz; Galioglu, Arman; Gurbuz, Yasar

    2017-05-01

    This journal presents a new high dynamic range ROIC with smart pixel which consists of two pre-amplifiers that are controlled by a circuit inside the pixel. Each pixel automatically decides which pre-amplifier is used according to the incoming illumination level. Instead of using single pre-amplifier, two input pre-amplifiers, which are optimized for different signal levels, are placed inside each pixel. The smart circuit mechanism, which decides the best input circuit according to the incoming light level, is also designed for each pixel. In short, an individual pixel has the ability to select the best input amplifier circuit that performs the best/highest SNR for the incoming signal level. A 32 × 32 ROIC prototype chip is designed to demonstrate the concept in 0.18 μ m CMOS technology. The prototype is optimized for NIR and SWIR bands. Instead of a detector, process variation optimized current sources are placed inside the ROIC. The chip achieves minimum 8.6 e- input referred noise and 98.9 dB dynamic range. It has the highest dynamic range in the literature in terms of analog ROICs for SWIR band. It is operating in room temperature and power consumption is 2.8 μ W per pixel.

  9. Comparison of linear intrascan and interscan dynamic ranges of Orbitrap and ion-mobility time-of-flight mass spectrometers.

    Science.gov (United States)

    Kaufmann, Anton; Walker, Stephan

    2017-11-30

    The linear intrascan and interscan dynamic ranges of mass spectrometers are important in metabolome and residue analysis. A large linear dynamic range is mandatory if both low- and high-abundance ions have to be detected and quantitated in heavy matrix samples. These performance criteria, as provided by modern high-resolution mass spectrometry (HRMS), were systematically investigated. The comparison included two generations of Orbitraps, and an ion mobility quadrupole time-of-flight (QTOF) system In addition, different scan modes, as provided by the utilized instruments, were investigated. Calibration curves of different compounds covering a concentration range of five orders of magnitude were measured to evaluate the linear interscan dynamic range. The linear intrascan dynamic range and the resulting mass accuracy were evaluated by repeating these measurements in the presence of a very intense background. Modern HRMS instruments can show linear dynamic ranges of five orders of magnitude. Often, however, the linear dynamic range is limited by the detection capability (sensitivity and selectivity) and by the electrospray ionization. Orbitraps, as opposed to TOF instruments, show a reduced intrascan dynamic range. This is due to the limited C-trap and Orbitrap capacity. The tested TOF instrument shows poorer mass accuracies than the Orbitraps. In contrast, hyphenation with an ion-mobility device seems not to affect the linear dynamic range. The linear dynamic range of modern HRMS instrumentation has been significantly improved. This also refers to the virtual absence of systematic mass shifts at high ion abundances. The intrascan dynamic range of the current Orbitrap technology may still be a limitation when analyzing complex matrix extracts. On the other hand, the linear dynamic range is not only limited by the detector technology, but can also be shortened by peripheral devices, where the ionization and transfer of ions take place. Copyright © 2017 John Wiley

  10. A large dynamic range radiation-tolerant analog memory in a quarter- micron CMOS technology

    CERN Document Server

    Anelli, G; Rivetti, A

    2001-01-01

    An analog memory prototype containing 8*128 cells has been designed in a commercial quarter-micron CMOS process. The aim of this work is to investigate the possibility of designing large dynamic range mixed-mode switched capacitor circuits for high-energy physics (HEP) applications in deep submicron CMOS technologies. Special layout techniques have been used to make the circuit radiation tolerant. The memory cells employ gate-oxide capacitors for storage, permitting a very high density. A voltage write-voltage read architecture has been chosen to minimize the sensitivity to absolute capacitor values. The measured input voltage range is 2.3 V (the power supply voltage V/sub DD/ is equal to 2.5 V), with a linearity of almost 8 bits over 2 V. The dynamic range is more than 11 bits. The pedestal variation is +or-0.5 mV peak-to-peak. The noise measured, which is dominated by the noise of the measurement setup, is around 0.8 mV rms. The characteristics of the memory have been measured before irradiation and after 1...

  11. Configurable Electronics with Low Noise and 14-bit Dynamic Range for Photodiode-based Photon Detectors

    CERN Document Server

    Müller, H; Yin, Z; Zhou, D; Cao, X; Li, Q; Liu, Y; Zou, F; Skaali, B; Awes, T C

    2006-01-01

    We describe the principles and measured performance characteristics of custom configurable 32-channel shaper/digitizer Front End Electronics (FEE) cards with 14-bit dynamic range for use with gain-adjustable photon detectors. The electronics has been designed for the PHOS calorimeter of ALICE with avalanche photodiode (APD) readout operated at -25 C ambient temperature and a signal shaping time of $1 {\\mu}s$. The electronics has also been adopted by the EMCal detector of ALICE with the same APD readout, but operated at an ambient temperature of +20 C and with a shaping time of 100ns. The CR-RC2 signal shapers on the FEE cards are implemented in discrete logic on a 10-layer board with two shaper sections for each input channel. The two shaper sections with gain ratio of 16:1 are digitized by 10-bit ADCs and provide an effective dynamic range of 14 bits. Gain adjustment for each individual APD is available through 32 bias voltage control registers of 10-bit range. The fixed gains and shaping times of the pole-z...

  12. High dynamic range CMOS-based mammography detector for FFDM and DBT

    Science.gov (United States)

    Peters, Inge M.; Smit, Chiel; Miller, James J.; Lomako, Andrey

    2016-03-01

    Digital Breast Tomosynthesis (DBT) requires excellent image quality in a dynamic mode at very low dose levels while Full Field Digital Mammography (FFDM) is a static imaging modality that requires high saturation dose levels. These opposing requirements can only be met by a dynamic detector with a high dynamic range. This paper will discuss a wafer-scale CMOS-based mammography detector with 49.5 μm pixels and a CsI scintillator. Excellent image quality is obtained for FFDM as well as DBT applications, comparing favorably with a-Se detectors that dominate the X-ray mammography market today. The typical dynamic range of a mammography detector is not high enough to accommodate both the low noise and the high saturation dose requirements for DBT and FFDM applications, respectively. An approach based on gain switching does not provide the signal-to-noise benefits in the low-dose DBT conditions. The solution to this is to add frame summing functionality to the detector. In one X-ray pulse several image frames will be acquired and summed. The requirements to implement this into a detector are low noise levels, high frame rates and low lag performance, all of which are unique characteristics of CMOS detectors. Results are presented to prove that excellent image quality is achieved, using a single detector for both DBT as well as FFDM dose conditions. This method of frame summing gave the opportunity to optimize the detector noise and saturation level for DBT applications, to achieve high DQE level at low dose, without compromising the FFDM performance.

  13. Short-range order above the Curie temperature in the dynamic spin-fluctuation theory

    International Nuclear Information System (INIS)

    Melnikov, N.B.; Reser, B.I.

    2016-01-01

    Based on the dynamic spin-fluctuation theory, we study the spin-density correlations in the ferromagnetic metals. We obtain computational formulae for the correlation function and correlation radius in different approximations of the theory. Using these formulae, we calculate the magnetic short-range order above the Curie temperature in bcc Fe. Results of the calculation confirm our theoretical prediction that the inverse correlation radius increases linearly with temperature for T sufficiently large. The calculated short-range order is small but sufficient to correctly describe neutron scattering experiments. A considerable amount of the short-range order is shown to persist up to temperatures much higher than the Curie temperature. - Highlights: • We study the spin correlations in ferromagnetic metals above the Curie temperature. • We derive computational formulae for the spin correlator and correlation radius. • The correlation radius decreases inversely with temperature over a wide interval. • The calculated short-range order in Fe is small, in agreement with experiment. • A considerable amount of short-range order in Fe persists up to high temperatures.

  14. Possible variations of dynamics in pp collisions within the CERN ISR energy range

    International Nuclear Information System (INIS)

    Chew, C.K.; Liang, T.Y.

    1987-01-01

    The possible dynamics occurring in pp collisions at different energy within the CERN ISR energy range is investigated using the quark statistical model. It is found that probably only direct collisions occur for square root s below 8 GeV. The fragmentation process begins to develop above 8 GeV. This process has a linear dependence of square root s from about 20 GeV and reaches saturation at about 100 GeV. The study also revealed some interesting results when large P/sub T/ data are investigated using the model

  15. Pixel-by-pixel local dimming for high-dynamic-range liquid crystal displays.

    Science.gov (United States)

    Chen, Haiwei; Zhu, Ruidong; Li, Ming-Chun; Lee, Seok-Lyul; Wu, Shin-Tson

    2017-02-06

    We propose a high dynamic range (HDR) liquid crystal display (LCD) with pixel-level local dimming. The device structure consists of a pixelated LCD dimming panel to control the backlight intensity entering the master LCD panel. According to our analysis and test cell experiment, this dual-panel display system possesses exceedingly high contrast ratio (> 1,000,000:1) and high bit-depth (> 14 bits) at merely 5 volts. Meanwhile, to mitigate the Moiré effect induced by the cascaded thin-film transistor (TFT) backplanes, we separate the two LCD panels with a polarization-dependent scattering film. The pros and cons of this HDR display are discussed.

  16. Ultra-sensitive wide dynamic range temperature sensor based on in-fiber Lyot interferometer

    Science.gov (United States)

    Nikbakht, Hamed; Poorghdiri Isfahani, Mohamad Hosein; Latifi, Hamid

    2017-04-01

    An in-fiber Lyot interferometer for temperature measurement is presented. The sensor utilizes high temperature-dependence of the birefringence in Panda polarization maintaining fibers to achieve high resolution in temperature measurements. Temperature variation modulates the phase difference between the polarization modes propagating in different modes of the Panda fiber. The Lyot interferometer produces a spectrum which varies with the phase difference. Therefore, by monitoring this spectrum a high resolution of 0.003°C was achieved. A fiber Bragg grating is added to the setup to expand its dynamic range. This sensor does not need complicated fabrication process and can be implemented in many applications.

  17. The Interplay between Long- and Short-Range Temporal Correlations Shapes Cortex Dynamics across Vigilance States.

    Science.gov (United States)

    Meisel, Christian; Klaus, Andreas; Vyazovskiy, Vladyslav V; Plenz, Dietmar

    2017-10-18

    Increasing evidence suggests that cortical dynamics during wake exhibits long-range temporal correlations suitable to integrate inputs over extended periods of time to increase the signal-to-noise ratio in decision making and working memory tasks. Accordingly, sleep has been suggested as a state characterized by a breakdown of long-range correlations. However, detailed measurements of neuronal timescales that support this view have so far been lacking. Here, we show that the cortical timescales measured at the individual neuron level in freely behaving male rats change as a function of vigilance state and time awake. Although quiet wake and rapid eye movement (REM) sleep are characterized by similar, long timescales, these long timescales are abrogated in non-REM sleep. We observe that cortex dynamics exhibits rapid transitions between long-timescale states and sleep-like states governed by short timescales even during wake. This becomes particularly evident during sleep deprivation, when the interplay between these states can lead to an increasing disruption of long timescales that are restored after sleep. Experiments and modeling identify the intrusion of neuronal offline periods as a mechanism that disrupts the long timescales arising from reverberating cortical network activity. Our results provide novel mechanistic and functional links among behavioral manifestations of sleep, wake, and sleep deprivation and specific measurable changes in the network dynamics relevant for characterizing the brain's changing information-processing capabilities. They suggest a network-level function of sleep to reorganize cortical networks toward states governed by long timescales to ensure efficient information integration for the time awake. SIGNIFICANCE STATEMENT Lack of sleep deteriorates several key cognitive functions, yet the neuronal underpinnings of these deficits have remained elusive. Cognitive capabilities are generally believed to benefit from a neural circuit

  18. Molecular dynamics simulations of short-range force systems on 1024-node hypercubes

    International Nuclear Information System (INIS)

    Plimpton, S.J.

    1990-01-01

    In this paper, two parallel algorithms for classical molecular dynamics are presented. The first assigns each processor to a subset of particles; the second assigns each to a fixed region of 3d space. The algorithms are implemented on 1024-node hypercubes for problems characterized by short-range forces, diffusion (so that each particle's neighbors change in time), and problem size ranging from 250 to 10000 particles. Timings for the algorithms on the 1024-node NCUBE/ten and the newer NCUBE 2 hypercubes are given. The latter is found to be competitive with a CRAY-XMP, running an optimized serial algorithm. For smaller problems the NCUBE 2 and CRAY-XMP are roughly the same; for larger ones the NCUBE 2 is up to twice as fast. Parallel efficiencies of the algorithms and communication parameters for the two hypercubes are also examined

  19. Population dynamics can be more important than physiological limits for determining range shifts under climate change.

    Science.gov (United States)

    Fordham, Damien A; Mellin, Camille; Russell, Bayden D; Akçakaya, Reşit H; Bradshaw, Corey J A; Aiello-Lammens, Matthew E; Caley, Julian M; Connell, Sean D; Mayfield, Stephen; Shepherd, Scoresby A; Brook, Barry W

    2013-10-01

    Evidence is accumulating that species' responses to climate changes are best predicted by modelling the interaction of physiological limits, biotic processes and the effects of dispersal-limitation. Using commercially harvested blacklip (Haliotis rubra) and greenlip abalone (Haliotis laevigata) as case studies, we determine the relative importance of accounting for interactions among physiology, metapopulation dynamics and exploitation in predictions of range (geographical occupancy) and abundance (spatially explicit density) under various climate change scenarios. Traditional correlative ecological niche models (ENM) predict that climate change will benefit the commercial exploitation of abalone by promoting increased abundances without any reduction in range size. However, models that account simultaneously for demographic processes and physiological responses to climate-related factors result in future (and present) estimates of area of occupancy (AOO) and abundance that differ from those generated by ENMs alone. Range expansion and population growth are unlikely for blacklip abalone because of important interactions between climate-dependent mortality and metapopulation processes; in contrast, greenlip abalone should increase in abundance despite a contraction in AOO. The strongly non-linear relationship between abalone population size and AOO has important ramifications for the use of ENM predictions that rely on metrics describing change in habitat area as proxies for extinction risk. These results show that predicting species' responses to climate change often require physiological information to understand climatic range determinants, and a metapopulation model that can make full use of this data to more realistically account for processes such as local extirpation, demographic rescue, source-sink dynamics and dispersal-limitation. © 2013 John Wiley & Sons Ltd.

  20. Quercus suber range dynamics by ecological niche modelling: from the Last Interglacial to present time

    Science.gov (United States)

    Vessella, Federico; Simeone, Marco Cosimo; Schirone, Bartolomeo

    2015-07-01

    Ecological Niche Modelling (ENM) is widely used to depict species potential occurrence according to environmental variables under different climatic scenarios. We tested the ENM approach to infer past range dynamics of cork oak, a keystone species of the Mediterranean Biome, from 130 ka to the present time. Hindcasting implications would deal with a better species risk assessment and conservation management for the future. We modelled present and past occurrence of cork oak using seven ENM algorithms, starting from 63,733 spatially unique presence points at 30 arc-second resolution. Fourteen environmental variables were used and four time slices were considered (Last Interglacial, Last Glacial Maximum, mid-Holocene and present time). A threshold-independent evaluation of the goodness-of-fit of the models was evaluated by means of ROC curve and fossil or historical evidences were used to validate the results. Four weighted average maps depicted the dynamics of area suitability for cork oak in the last 130 ka. The derived species autoecology allowed its long-term occurrence in the Mediterranean without striking range reduction or shifting. Fossil and historical post-processing validation support the modelled past spatial extension and a neglected species presence at Levantine until the recent time. Despite the severe climatic oscillation since the Last Glacial Maximum, cork oak potential distribution area experienced limited range changes, confirming its strong link with the Mediterranean Basin. The ecological amplitude of Quercus suber could be therefore adopted as a reference to trace the Mediterranean bioclimate area. A better knowledge of the past events of Mediterranean vegetation, a wider range of study species and environmental determinants are essential to inform us about its current state, its sensitivity to human impact and the potential responses to future changes.

  1. A wide-range model of two-group gross sections in the dynamics code HEXTRAN

    International Nuclear Information System (INIS)

    Kaloinen, E.; Peltonen, J.

    2002-01-01

    In dynamic analyses the thermal hydraulic conditions within the reactor core may have a large variation, which sets a special requirement on the modeling of cross sections. The standard model in the dynamics code HEXTRAN is the same as in the static design code HEXBU-3D/MODS. It is based on a linear and second order fitting of two-group cross sections on fuel and moderator temperature, moderator density and boron density. A new, wide-range model of cross sections developed in Fortum Nuclear Services for HEXBU-3D/MOD6 has been included as an option into HEXTRAN. In this model the nodal cross sections are constructed from seven state variables in a polynomial of more than 40 terms. Coefficients of the polynomial are created by a least squares fitting to the results of a large number of fuel assembly calculations. Depending on the choice of state variables for the spectrum calculations, the new cross section model is capable to cover local conditions from cold zero power to boiling at full power. The 5. dynamic benchmark problem of AER is analyzed with the new option and results are compared to calculations with the standard model of cross sections in HEXTRAN (Authors)

  2. Quantifying Long-Range Interactions and Coherent Structure in Multi-Agent Dynamics.

    Science.gov (United States)

    Cliff, Oliver M; Lizier, Joseph T; Wang, X Rosalind; Wang, Peter; Obst, Oliver; Prokopenko, Mikhail

    2017-01-01

    We develop and apply several novel methods quantifying dynamic multi-agent team interactions. These interactions are detected information-theoretically and captured in two ways: via (i) directed networks (interaction diagrams) representing significant coupled dynamics between pairs of agents, and (ii) state-space plots (coherence diagrams) showing coherent structures in Shannon information dynamics. This model-free analysis relates, on the one hand, the information transfer to responsiveness of the agents and the team, and, on the other hand, the information storage within the team to the team's rigidity and lack of tactical flexibility. The resultant interaction and coherence diagrams reveal implicit interactions, across teams, that may be spatially long-range. The analysis was verified with a statistically significant number of experiments (using simulated football games, produced during RoboCup 2D Simulation League matches), identifying the zones of the most intense competition, the extent and types of interactions, and the correlation between the strength of specific interactions and the results of the matches.

  3. Context-dependent JPEG backward-compatible high-dynamic range image compression

    Science.gov (United States)

    Korshunov, Pavel; Ebrahimi, Touradj

    2013-10-01

    High-dynamic range (HDR) imaging is expected, together with ultrahigh definition and high-frame rate video, to become a technology that may change photo, TV, and film industries. Many cameras and displays capable of capturing and rendering both HDR images and video are already available in the market. The popularity and full-public adoption of HDR content is, however, hindered by the lack of standards in evaluation of quality, file formats, and compression, as well as large legacy base of low-dynamic range (LDR) displays that are unable to render HDR. To facilitate the wide spread of HDR usage, the backward compatibility of HDR with commonly used legacy technologies for storage, rendering, and compression of video and images are necessary. Although many tone-mapping algorithms are developed for generating viewable LDR content from HDR, there is no consensus of which algorithm to use and under which conditions. We, via a series of subjective evaluations, demonstrate the dependency of the perceptual quality of the tone-mapped LDR images on the context: environmental factors, display parameters, and image content itself. Based on the results of subjective tests, it proposes to extend JPEG file format, the most popular image format, in a backward compatible manner to deal with HDR images also. An architecture to achieve such backward compatibility with JPEG is proposed. A simple implementation of lossy compression demonstrates the efficiency of the proposed architecture compared with the state-of-the-art HDR image compression.

  4. A research on radiation calibration of high dynamic range based on the dual channel CMOS

    Science.gov (United States)

    Ma, Kai; Shi, Zhan; Pan, Xiaodong; Wang, Yongsheng; Wang, Jianghua

    2017-10-01

    The dual channel complementary metal-oxide semiconductor (CMOS) can get high dynamic range (HDR) image through extending the gray level of the image by using image fusion with high gain channel image and low gain channel image in a same frame. In the process of image fusion with dual channel, it adopts the coefficients of radiation response of a pixel from dual channel in a same frame, and then calculates the gray level of the pixel in the HDR image. For the coefficients of radiation response play a crucial role in image fusion, it has to find an effective method to acquire these parameters. In this article, it makes a research on radiation calibration of high dynamic range based on the dual channel CMOS, and designs an experiment to calibrate the coefficients of radiation response for the sensor it used. In the end, it applies these response parameters in the dual channel CMOS which calibrates, and verifies the correctness and feasibility of the method mentioned in this paper.

  5. A High-Dynamic-Range Optical Remote Sensing Imaging Method for Digital TDI CMOS

    Directory of Open Access Journals (Sweden)

    Taiji Lan

    2017-10-01

    Full Text Available The digital time delay integration (digital TDI technology of the complementary metal-oxide-semiconductor (CMOS image sensor has been widely adopted and developed in the optical remote sensing field. However, the details of targets that have low illumination or low contrast in scenarios of high contrast are often drowned out because of the superposition of multi-stage images in digital domain multiplies the read noise and the dark noise, thus limiting the imaging dynamic range. Through an in-depth analysis of the information transfer model of digital TDI, this paper attempts to explore effective ways to overcome this issue. Based on the evaluation and analysis of multi-stage images, the entropy-maximized adaptive histogram equalization (EMAHE algorithm is proposed to improve the ability of images to express the details of dark or low-contrast targets. Furthermore, in this paper, an image fusion method is utilized based on gradient pyramid decomposition and entropy weighting of different TDI stage images, which can improve the detection ability of the digital TDI CMOS for complex scenes with high contrast, and obtain images that are suitable for recognition by the human eye. The experimental results show that the proposed methods can effectively improve the high-dynamic-range imaging (HDRI capability of the digital TDI CMOS. The obtained images have greater entropy and average gradients.

  6. Optimal design of a vehicle magnetorheological damper considering the damping force and dynamic range

    International Nuclear Information System (INIS)

    Nguyen, Quoc-Hung; Choi, Seung-Bok

    2009-01-01

    This paper presents an optimal design of a passenger vehicle magnetorheological (MR) damper based on finite element analysis. The MR damper is constrained in a specific volume and the optimization problem identifies the geometric dimensions of the damper that minimize an objective function. The objective function consists of the damping force, the dynamic range, and the inductive time constant of the damper. After describing the configuration of the MR damper, the damping force and dynamic range are obtained on the basis of the Bingham model of an MR fluid. Then, the control energy (power consumption of the damper coil) and the inductive time constant are derived. The objective function for the optimization problem is determined based on the solution of the magnetic circuit of the initial damper. Subsequently, the optimization procedure, using a golden-section algorithm and a local quadratic fitting technique, is constructed via commercial finite element method parametric design language. Using the developed optimization tool, optimal solutions of the MR damper, which are constrained in a specific cylindrical volume defined by its radius and height, are determined and a comparative work on damping force and inductive time constant between the initial and optimal design is undertaken

  7. Host-Range Dynamics of Cochliobolus lunatus: From a Biocontrol Agent to a Severe Environmental Threat

    Directory of Open Access Journals (Sweden)

    Bengyella Louis

    2014-01-01

    Full Text Available We undertook an investigation to advance understanding of the host-range dynamics and biocontrol implications of Cochliobolus lunatus in the past decade. Potato (Solanum tuberosum L farms were routinely surveyed for brown-to-black leaf spot disease caused by C. lunatus. A biphasic gene data set was assembled and databases were mined for reported hosts of C. lunatus in the last decade. The placement of five virulent strains of C. lunatus causing foliar necrosis of potato was studied with microscopic and phylogenetic tools. Analysis of morphology showed intraspecific variations in stromatic tissues among the virulent strains causing foliar necrosis of potato. A maximum likelihood inference based on GPDH locus separated C. lunatus strains into subclusters and revealed the emergence of unclustered strains. The evolving nutritional requirement of C. lunatus in the last decade is exhibited by the invasion of vertebrates, invertebrates, dicots, and monocots. Our results contribute towards a better understanding of the host-range dynamics of C. lunatus and provide useful implications on the threat posed to the environment when C. lunatus is used as a mycoherbicide.

  8. A high dynamic range structured light means for the 3D measurement of specular surface

    Science.gov (United States)

    Song, Zhan; Jiang, Hualie; Lin, Haibo; Tang, Suming

    2017-08-01

    This paper presents a novel structured light approach for the 3D reconstruction of specular surface. The binary shifting strip is adopted as structured light pattern instead of conventional sinusoidal pattern. Based on the framework of conventional High Dynamic Range (HDR) imaging technique, an efficient means is first introduced to estimate the camera response function. And then, dynamic range of the generated radiance map is compressed in the gradient domain by introducing an attenuation function. Subject to the change of lighting conditions caused by projecting different structured light patterns, the structure light image with middle exposure level is selected as the reference image and used for the slight adjustment of the primary fused image. Finally, the regenerated structured light images with well exposing condition are used for 3D reconstruction of the specular surface. To evaluate performance of the method, some stainless stamping parts with strong reflectivity are used for the experiments. And the results showed that, different specular targets with various shapes can be precisely reconstructed by the proposed method.

  9. A low-noise wide dynamic range CMOS image sensor with low and high temperatures resistance

    Science.gov (United States)

    Mizobuchi, Koichi; Adachi, Satoru; Tejada, Jose; Oshikubo, Hiromichi; Akahane, Nana; Sugawa, Shigetoshi

    2008-02-01

    A temperature-resistant 1/3 inch SVGA (800×600 pixels) 5.6 μm pixel pitch wide-dynamic-range (WDR) CMOS image sensor has been developed using a lateral-over-flow-integration-capacitor (LOFIC) in a pixel. The sensor chips are fabricated through 0.18 μm 2P3M process with totally optimized front-end-of-line (FEOL) & back-end-of-line (BEOL) for a lower dark current. By implementing a low electrical field potential design for photodiodes, reducing damages, recovering crystal defects and terminating interface states in the FEOL+BEOL, the dark current is improved to 12 e - /pixel-sec at 60 deg.C with 50% reduction from the previous very-low-dark-current (VLDC) FEOL and its contribution to the temporal noise is improved. Furthermore, design optimizations of the readout circuits, especially a signal-and noise-hold circuit and a programmable-gain-amplifier (PGA) are also implemented. The measured temporal noise is 2.4 e -rms at 60 fps (:36 MHz operation). The dynamic-range (DR) is extended to 100 dB with 237 ke - full well capacity. In order to secure the temperature-resistance, the sensor chip also receives both an inorganic cap onto micro lens and a metal hermetic seal package assembly. Image samples at low & high temperatures show significant improvement in image qualities.

  10. Design of a full-dynamic-range balanced detection heterodyne gyroscope with common-path configuration.

    Science.gov (United States)

    Lin, Chu-En; Yu, Chih-Jen; Chen, Chii-Chang

    2013-04-22

    In this article, we propose an optical heterodyne common-path gyroscope which has common-path configuration and full-dynamic range. Different from traditional non-common-path optical heterodyne technique such as Mach-Zehnder or Michelson interferometers, we use a two-frequency laser light source (TFLS) which can generate two orthogonally polarized light with a beat frequency has a common-path configuration. By use of phase measurement, this optical heterodyne gyroscope not only has the capability to overcome the drawback of the traditional interferometric fiber optic gyro: lack for full-dynamic range, but also eliminate the total polarization rotation caused by SMFs. Moreover, we also demonstrate the potential of miniaturizing this gyroscope as a chip device. Theoretically, if we assume that the wavelength of the laser light is 1550nm, the SMFs are 250m in length, and the radius of the fiber ring is 3.5cm, the bias stability is 0.872 deg/hr.

  11. Extension of photomultiplier tube dynamic range for the LHAASO-KM2A electromagnetic particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Hongkui, E-mail: lvhk@ihep.ac.cn [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Sheng, Xiangdong; He, Huihai; Liu, Jia [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Zhongquan [Shandong University, Jinan 250100 (China); Hou, Chao; Zhao, Jing [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2015-05-01

    In the Large High Altitude Air Shower Observatory (LHAASO), the 1 km{sup 2} array (KM2A) requires linear measurement of optical intensity with a wide dynamic range. Over 5000 photomultiplier tubes (PMTs) are employed in this experiment and developed as “two outputs” device (anode and dynode) to meet the relevant requirements. In this study, the linearity of the anode and the eighth dynode (DY8), which is limited by space charge effects and mainly related to the relative dynode voltage ratios of the PMT divider, is examined. A voltage divider for the Hamamatsu R11102 PMT is designed and a dramatically enhanced linearity is demonstrated. Test results show that this design can cover a wide dynamic range from 20 to 2×10{sup 5} photoelectrons and achieve a peak anode current of 380 mA at a PMT gain of 10{sup 5}, which satisfies the requirements of KM2A electromagnetic particle detectors. The circuit design has been successfully simulated using the simulation software Multisim. The details of PMT performance tests and simulations are described.

  12. Extension of photomultiplier tube dynamic range for the LHAASO-KM2A electromagnetic particle detectors

    Science.gov (United States)

    Lv, Hongkui; Sheng, Xiangdong; He, Huihai; Liu, Jia; Zhang, Zhongquan; Hou, Chao; Zhao, Jing

    2015-05-01

    In the Large High Altitude Air Shower Observatory (LHAASO), the 1 km2 array (KM2A) requires linear measurement of optical intensity with a wide dynamic range. Over 5000 photomultiplier tubes (PMTs) are employed in this experiment and developed as "two outputs" device (anode and dynode) to meet the relevant requirements. In this study, the linearity of the anode and the eighth dynode (DY8), which is limited by space charge effects and mainly related to the relative dynode voltage ratios of the PMT divider, is examined. A voltage divider for the Hamamatsu R11102 PMT is designed and a dramatically enhanced linearity is demonstrated. Test results show that this design can cover a wide dynamic range from 20 to 2×105 photoelectrons and achieve a peak anode current of 380 mA at a PMT gain of 105, which satisfies the requirements of KM2A electromagnetic particle detectors. The circuit design has been successfully simulated using the simulation software Multisim. The details of PMT performance tests and simulations are described.

  13. Extension of photomultiplier tube dynamic range for the LHAASO-KM2A electromagnetic particle detectors

    International Nuclear Information System (INIS)

    Lv, Hongkui; Sheng, Xiangdong; He, Huihai; Liu, Jia; Zhang, Zhongquan; Hou, Chao; Zhao, Jing

    2015-01-01

    In the Large High Altitude Air Shower Observatory (LHAASO), the 1 km 2 array (KM2A) requires linear measurement of optical intensity with a wide dynamic range. Over 5000 photomultiplier tubes (PMTs) are employed in this experiment and developed as “two outputs” device (anode and dynode) to meet the relevant requirements. In this study, the linearity of the anode and the eighth dynode (DY8), which is limited by space charge effects and mainly related to the relative dynode voltage ratios of the PMT divider, is examined. A voltage divider for the Hamamatsu R11102 PMT is designed and a dramatically enhanced linearity is demonstrated. Test results show that this design can cover a wide dynamic range from 20 to 2×10 5 photoelectrons and achieve a peak anode current of 380 mA at a PMT gain of 10 5 , which satisfies the requirements of KM2A electromagnetic particle detectors. The circuit design has been successfully simulated using the simulation software Multisim. The details of PMT performance tests and simulations are described

  14. Use of multiple CT scans to accommodate large objects and stretch dynamic range of detectability

    Energy Technology Data Exchange (ETDEWEB)

    Sivers, E.A.

    1994-09-01

    Rotate-only X-ray CT scanners are preferred for their speed and dose utilization, but suffer from the restriction that the scanned object must fit within the radiation beam. In addition, the ratio of signals unattenuated by air paths to those penetrating thick, dense objects often exceeds the dynamic range of conventional X-ray detectors. Both of these disadvantages can be removed for objects larger than the X-ray beam by taking multiple scans, each of which exposes only part of the object. These partial data sets can then be merged to produce a complete data set. For most objects, it is also possible to separately expose regions in which the ratios between the extremes of attenuation are much lower than that between air and the maximum path length. It is therefore possible to use a higher flux to image denser regions, improving signal-to-noise ratios and yielding images superior to those of larger scanners having the same dynamic range,

  15. Analog Filtering of Large Solvent Signals for Improved Dynamic Range in High-Resolution NMR

    Science.gov (United States)

    Redfield, A. G.; Kunz, S. D.

    1998-01-01

    The large solvent signal from samples in H2O solvent still challenges the dynamic range capability of any spectrometer. The solvent signal can be largely removed with a pair of simple resistor-capacitor (RC) high-pass filters when the solvent frequency is set at center band (zero frequency) using quadrature detection, withRC∼ 0.5 ms. However, an ∼0.5-ms transient remains at initial time, which we reduce fourfold for a short time only, just before the A/D converter, by means of a variable-gain amplifier, and later restore with software. This modification can result in a nearly fourfold increase in dynamic range. When we converted to a frequency-shifted mode (A. G. Redfield and S. D. Kunz, 1994,J. Magn. Reson. A108, 234-237) we replaced theRChigh-pass filter with a quadrature feedback notch filter tuned to the solvent frequency (5.06 kHz). This filter is an example of a class of two-input/two-output filters which maintain the spectral integrity (image-free character) of quadrature signals. Digital filters of the same type are also considered briefly. We discuss the implications of these ideas for spectrometer input design, including schemes for elimination of radiation damping, and effects of probe bandwidth on extreme oversampling.

  16. Dynamic Data Filtering of Long-Range Doppler LiDAR Wind Speed Measurements

    Directory of Open Access Journals (Sweden)

    Hauke Beck

    2017-06-01

    Full Text Available Doppler LiDARs have become flexible and versatile remote sensing devices for wind energy applications. The possibility to measure radial wind speed components contemporaneously at multiple distances is an advantage with respect to meteorological masts. However, these measurements must be filtered due to the measurement geometry, hard targets and atmospheric conditions. To ensure a maximum data availability while producing low measurement errors, we introduce a dynamic data filter approach that conditionally decouples the dependency of data availability with increasing range. The new filter approach is based on the assumption of self-similarity, that has not been used so far for LiDAR data filtering. We tested the accuracy of the dynamic data filter approach together with other commonly used filter approaches, from research and industry applications. This has been done with data from a long-range pulsed LiDAR installed at the offshore wind farm ‘alpha ventus’. There, an ultrasonic anemometer located approximately 2.8 km from the LiDAR was used as reference. The analysis of around 1.5 weeks of data shows, that the error of mean radial velocity can be minimised for wake and free stream conditions.

  17. Adaptive digital fringe projection technique for high dynamic range three-dimensional shape measurement.

    Science.gov (United States)

    Lin, Hui; Gao, Jian; Mei, Qing; He, Yunbo; Liu, Junxiu; Wang, Xingjin

    2016-04-04

    It is a challenge for any optical method to measure objects with a large range of reflectivity variation across the surface. Image saturation results in incorrect intensities in captured fringe pattern images, leading to phase and measurement errors. This paper presents a new adaptive digital fringe projection technique which avoids image saturation and has a high signal to noise ratio (SNR) in the three-dimensional (3-D) shape measurement of objects that has a large range of reflectivity variation across the surface. Compared to previous high dynamic range 3-D scan methods using many exposures and fringe pattern projections, which consumes a lot of time, the proposed technique uses only two preliminary steps of fringe pattern projection and image capture to generate the adapted fringe patterns, by adaptively adjusting the pixel-wise intensity of the projected fringe patterns based on the saturated pixels in the captured images of the surface being measured. For the bright regions due to high surface reflectivity and high illumination by the ambient light and surfaces interreflections, the projected intensity is reduced just to be low enough to avoid image saturation. Simultaneously, the maximum intensity of 255 is used for those dark regions with low surface reflectivity to maintain high SNR. Our experiments demonstrate that the proposed technique can achieve higher 3-D measurement accuracy across a surface with a large range of reflectivity variation.

  18. ATMOSPHERIC DYNAMICS OF TERRESTRIAL EXOPLANETS OVER A WIDE RANGE OF ORBITAL AND ATMOSPHERIC PARAMETERS

    Energy Technology Data Exchange (ETDEWEB)

    Kaspi, Yohai [Department of Earth and Planetary Sciences, Weizmann Institute of Science, 234 Herzl st., 76100, Rehovot (Israel); Showman, Adam P., E-mail: yohai.kaspi@weizmann.ac.il [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Blvd., Tucson, AZ 85721 (United States)

    2015-05-01

    The recent discoveries of terrestrial exoplanets and super-Earths extending over a broad range of orbital and physical parameters suggest that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super-Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone—including transitions to Snowball-like states and runaway-greenhouse feedbacks—depend on the equator-to-pole temperature differences, patterns of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, stellar flux, atmospheric mass, surface gravity, optical thickness, and planetary radius affect the atmospheric circulation and temperature distribution on such planets. Our simulations demonstrate that equator-to-pole temperature differences, meridional heat transport rates, structure and strength of the winds, and the hydrological cycle vary strongly with these parameters, implying that the sensitivity of the planet to global climate feedbacks will depend significantly on the atmospheric circulation. We elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet streams, Hadley and Ferrel cells, and latitudinal temperature differences. Finally, we discuss the implications for understanding how the atmospheric circulation influences the global climate.

  19. Dynamic range in BOLD modulation: lifespan aging trajectories and association with performance.

    Science.gov (United States)

    Kennedy, Kristen M; Boylan, Maria A; Rieck, Jenny R; Foster, Chris M; Rodrigue, Karen M

    2017-12-01

    Alteration of dynamic range of modulation to cognitive difficulty has been proposed as a salient predictor of cognitive aging. Here, we examine in 171 adults (aged 20-94 years) the effects of age on dynamic modulation of blood oxygenation-level dependent activation to difficulty in parametrically increasing working memory (WM) load (0-, 2-, 3-, and 4-back conditions). First, we examined parametric increases and decreases in activation to increasing WM load (positive modulation effect and negative modulation effect). Second, we examined the effect of age on modulation to difficulty (WM load) to identify regions that differed with age as difficulty increased (age-related positive and negative modulation effects). Weakened modulation to difficulty with age was found in both the positive modulation (middle frontal, superior/inferior parietal) and negative modulation effect (deactivated) regions (insula, cingulate, medial superior frontal, fusiform, and parahippocampal gyri, hippocampus, and lateral occipital cortex). Age-related alterations to positive modulation emerged later in the lifespan than negative modulation. Furthermore, these effects were significantly coupled in that greater upmodulation was associated with lesser downmodulation. Importantly, greater fronto-parietal upmodulation to difficulty and greater downmodulation of deactivated regions were associated with better task accuracy and upmodulation with better WM span measured outside the scanner. These findings suggest that greater dynamic range of modulation of activation to cognitive challenge is in service of current task performance, as well as generalizing to cognitive ability beyond the scanner task, lending support to its utility as a marker of successful cognitive aging. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. ATMOSPHERIC DYNAMICS OF TERRESTRIAL EXOPLANETS OVER A WIDE RANGE OF ORBITAL AND ATMOSPHERIC PARAMETERS

    International Nuclear Information System (INIS)

    Kaspi, Yohai; Showman, Adam P.

    2015-01-01

    The recent discoveries of terrestrial exoplanets and super-Earths extending over a broad range of orbital and physical parameters suggest that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super-Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone—including transitions to Snowball-like states and runaway-greenhouse feedbacks—depend on the equator-to-pole temperature differences, patterns of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, stellar flux, atmospheric mass, surface gravity, optical thickness, and planetary radius affect the atmospheric circulation and temperature distribution on such planets. Our simulations demonstrate that equator-to-pole temperature differences, meridional heat transport rates, structure and strength of the winds, and the hydrological cycle vary strongly with these parameters, implying that the sensitivity of the planet to global climate feedbacks will depend significantly on the atmospheric circulation. We elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet streams, Hadley and Ferrel cells, and latitudinal temperature differences. Finally, we discuss the implications for understanding how the atmospheric circulation influences the global climate

  1. The Effects of Dynamic Range of Motion Exercises and Static Stretching on Strength and Range of Motion of the Hip Joint.

    Science.gov (United States)

    Kanetzke, Carol A.

    The effects of Dynamic Range of Motion (D'ROM) exercises and static stretch on hip flexibility and hip strength were examined. One hundred one male and female college students were divided into three groups: D'ROM, static stretch (ST), and control (C). All subjects were measured before and after treatment for hip flexibility and strength. Two…

  2. Investigating the Partial Relationships Between Testability and the Dynamic Range-to-Domain Ratio

    Directory of Open Access Journals (Sweden)

    Zuhoor Al-Khanjari

    2003-11-01

    Full Text Available The word ‘testability’ has been used variously in the software community to represent a number of different concepts such as how easy it is to test a program or how easy it is to achieve execution coverage of certain program components. Voas and colleagues have used the word to capture a slightly different notion, namely the ease with which faults, if present in a program, can be revealed by the testing process. The significance of this concept is twofold. First, if it is possible to measure or estimate testability, it can guide the tester in deciding where to focus the testing effort. Secondly, knowledge about what makes some programs more testable than others can guide the developer so that design-for-test features are built in to the software. The propagation, infection and execution (PIE analysis technique has been proposed as a way of estimating the Voas notion of testability. Unfortunately, estimating testability via the PIE technique is a difficult and costly process. However, Voas has suggested a link with the metric, domain-to-range ratio (DRR. This paper reviews the various testability concepts and summarises the PIE technique. A prototype tool developed by the authors to automate part of the PIE analysis is described and a method is proposed for dynamically determining the inverse of the domain-to-range ratio. This inverse ratio can be considered more natural in some sense and the idea of calculating its value from program execution leads to the possibility of automating its determination. Some experiments have been performed to investigate empirically whether there is a partial link between testability and this dynamic range-to-domain ratio (DRDR. Statistical tests have shown that for some programs and computational functions there is a strong relationship, but for others the relationship is weak.

  3. Metastability and avalanche dynamics in strongly correlated gases with long-range interactions

    Science.gov (United States)

    Hruby, Lorenz; Dogra, Nishant; Landini, Manuele; Donner, Tobias; Esslinger, Tilman

    2018-03-01

    We experimentally study the stability of a bosonic Mott insulator against the formation of a density wave induced by long-range interactions and characterize the intrinsic dynamics between these two states. The Mott insulator is created in a quantum degenerate gas of 87-Rubidium atoms, trapped in a 3D optical lattice. The gas is located inside and globally coupled to an optical cavity. This causes interactions of global range, mediated by photons dispersively scattered between a transverse lattice and the cavity. The scattering comes with an atomic density modulation, which is measured by the photon flux leaking from the cavity. We initialize the system in a Mott-insulating state and then rapidly increase the global coupling strength. We observe that the system falls into either of two distinct final states. One is characterized by a low photon flux, signaling a Mott insulator, and the other is characterized by a high photon flux, which we associate with a density wave. Ramping the global coupling slowly, we observe a hysteresis loop between the two states—a further signature of metastability. A comparison with a theoretical model confirms that the metastability originates in the competition between short- and global-range interactions. From the increasing photon flux monitored during the switching process, we find that several thousand atoms tunnel to a neighboring site on the timescale of the single-particle dynamics. We argue that a density modulation, initially forming in the compressible surface of the trapped gas, triggers an avalanche tunneling process in the Mott-insulating region.

  4. Diverse range dynamics and dispersal routes of plants on the Tibetan Plateau during the late Quaternary.

    Directory of Open Access Journals (Sweden)

    Haibin Yu

    Full Text Available Phylogeographical studies have suggested that several plant species on the Tibetan Plateau (TP underwent recolonization during the Quaternary and may have had distinct range dynamics in response to the last glacial. To further test this hypothesis and locate the possible historical dispersal routes, we selected 20 plant species from different parts of the TP and modeled their geographical distributions over four time periods using species distribution models (SDMs. Furthermore, we applied the least-cost path method together with SDMs and shared haplotypes to estimate their historical dispersal corridors. We identified three general scenarios of species distribution change during the late Quaternary: the 'contraction-expansion' scenario for species in the northeastern TP, the 'expansion-contraction' scenario for species in the southeast and the 'stable' scenario for widespread species. During the Quaternary, we identified that these species were likely to recolonize along the low-elevation valleys, huge mountain ranges and flat plateau platform (e.g. the Yarlung Zangbo Valley and the Himalaya. We inferred that Quaternary cyclic glaciations along with the various topographic and climatic conditions of the TP could have resulted in the diverse patterns of range shift and dispersal of Tibetan plant species. Finally, we believe that this study would provide valuable insights for the conservation of alpine species under future climate change.

  5. Development of a High Dynamic Range Pixel Array Detector for Synchrotrons and XFELs

    Science.gov (United States)

    Weiss, Joel Todd

    Advances in synchrotron radiation light source technology have opened new lines of inquiry in material science, biology, and everything in between. However, x-ray detector capabilities must advance in concert with light source technology to fully realize experimental possibilities. X-ray free electron lasers (XFELs) place particularly large demands on the capabilities of detectors, and developments towards diffraction-limited storage ring sources also necessitate detectors capable of measuring very high flux [1-3]. The detector described herein builds on the Mixed Mode Pixel Array Detector (MM-PAD) framework, developed previously by our group to perform high dynamic range imaging, and the Adaptive Gain Integrating Pixel Detector (AGIPD) developed for the European XFEL by a collaboration between Deustsches Elektronen-Synchrotron (DESY), the Paul-Scherrer-Institute (PSI), the University of Hamburg, and the University of Bonn, led by Heinz Graafsma [4, 5]. The feasibility of combining adaptive gain with charge removal techniques to increase dynamic range in XFEL experiments is assessed by simulating XFEL scatter with a pulsed infrared laser. The strategy is incorporated into pixel prototypes which are evaluated with direct current injection to simulate very high incident x-ray flux. A fully functional 16x16 pixel hybrid integrating x-ray detector featuring several different pixel architectures based on the prototypes was developed. This dissertation describes its operation and characterization. To extend dynamic range, charge is removed from the integration node of the front-end amplifier without interrupting integration. The number of times this process occurs is recorded by a digital counter in the pixel. The parameter limiting full well is thereby shifted from the size of an integration capacitor to the depth of a digital counter. The result is similar to that achieved by counting pixel array detectors, but the integrators presented here are designed to tolerate a

  6. Boundary driven Kawasaki process with long-range interaction: dynamical large deviations and steady states

    International Nuclear Information System (INIS)

    Mourragui, Mustapha; Orlandi, Enza

    2013-01-01

    A particle system with a single locally-conserved field (density) in a bounded interval with different densities maintained at the two endpoints of the interval is under study here. The particles interact in the bulk through a long-range potential parametrized by β⩾0 and evolve according to an exclusion rule. It is shown that the empirical particle density under the diffusive scaling solves a quasilinear integro-differential evolution equation with Dirichlet boundary conditions. The associated dynamical large deviation principle is proved. Furthermore, when β is small enough, it is also demonstrated that the empirical particle density obeys a law of large numbers with respect to the stationary measures (hydrostatic). The macroscopic particle density solves a non-local, stationary, transport equation. (paper)

  7. OTDM Networking for Short Range High-Capacity Highly Dynamic Networks

    DEFF Research Database (Denmark)

    Medhin, Ashenafi Kiros

    is on short range highly dynamic networks, catering to data center needs. The investigation concerns optical network scenarios, and experimental implementations of high bit rate serial data packet generation and reception, scalable optical packet labeling, simple optical label extraction and stable ultra......This PhD thesis aims at investigating the possibility of designing energy-efficient high-capacity (up to Tbit/s) optical network scenarios, leveraging on the effect of collective switching of many bits simultaneously, as is inherent in high bit rate serial optical data signals. The focus...... Tbit/s data packets, and time lens based serial-to-parallel converter is employed to demultiplex each high-capacity packet into lower bit rate tributaries. A novel optical label scheme is suggested and experimentally demonstrated, where the label information is inserted in-band in the broad signal...

  8. A novel multiple cues based image fusing algorithm for high dynamic range image generation

    Science.gov (United States)

    Wu, Xiaojun; Song, Zhan; Yu, Gang; Zheng, Feng

    2012-01-01

    Multiple-exposure-based methods have been an effective means for high dynamic range (HDR) imaging technology. The current methods are greatly dependent on tone mapping, and most of them are unable to accurately recover the local details and colors of the scene. In this work, we present a novel HDR method by using multiple image cues for the image merging process. Firstly, all the images with various exposure times are divided into some uniform sub-regions and an exposure estimation technique is implemented to judge the well exposed one. With all the image blocks have best exposing quality are selected, a blending function is proposed to remove the transition boundaries between these blocks. A fidelity metric index is introduced to assess the final fusion image, and experimental results on public image libraries are given to demonstrate its high performance.

  9. Increase of the dynamic range of catchup experiments by high-pass filtering

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D.J.

    1995-08-01

    The release-catchup shock experiment is an important tool for measuring the speed of sound in compressed matter. The catchup of the release wave to the leading shock is sensitively detected optically, through an indicating fluid which produces light approximately to the 4th power of the shock pressure. However, this sensitivity demands a dynamic range which exceeds the capabilities of our digitizer. The catchup signature lies at the top of a flat pulse, thus any signal clipping is a catastrophic loss of data. We have invented a simple and accurate method for recording the catchup signature that is insensitive to signal clipping. A high pass circuit prior to the digitizer is used with post experiment integration. The insensitivity to clipping allows recording the catchup signature at higher gain, and thus with an improved signal to noise ratio.

  10. Extension of dynamic range in X-ray radiography using multi-color scintillation detector

    CERN Document Server

    Nittoh, K; Sakurai, T; Yoshida, T; Mochiki, K I

    2003-01-01

    A new imaging system using the multi-color scintillator Gd sub 2 O sub 2 S:Eu has been developed for the X-ray radiography. In this method a color Charge Coupled Device detects the weak blue and green photons associated with the transitions from the terms like sup 5 D sub 1 and sup 5 D sub 2 in the Eu-ions as well as the dominant red photons. As these transitions become appreciable and saturate at quite different intensity levels of the X-ray, we can realize a big extension of the dynamic range of the imaging almost by hundred times in comparison with the conventional monochromatic method. As a result, the new system makes it possible to take a clear image of any complex object, which consists of various parts of the different X-ray penetrability, from plastic to heavy metal, at a single shot.

  11. Increasing input power dynamic range of SOA by shifting the transparent wavelength of tunable optical filter

    DEFF Research Database (Denmark)

    Yu, Jianjun; Jeppesen, Palle

    2001-01-01

    Gain-saturation-induced self-phase modulation (SPM) leading to pulse distortion in a semiconductor optical amplifier (SOA) is overcome by shifting a tunable optical filter (TOF). A recovered or broadened pulse can be obtained after filtering the amplified pulse in the SOA even if the short pulse...... to a longer wavelength for RZ signals and to a shorter for NRZ signals. 80-Gb/s optical time division multiplexing (OTDM) signal amplification in the SOA is demonstrated for the first time. We also demonstrate that a large IPDR for the 80-Gb/s OTDM signal can be obtained by shifting the TOF....... is only 2-3 ps long. The input power dynamic range (IPDR) can be strongly increased by shifting the TOF and the direction of the shifted transparent wavelength is different for 10 Gb/s return-to-zero (RZ) or nonreturn-to-zero (NRZ) signals. The transparent wavelength of the TOF should be shifted...

  12. High Precision Stokes Polarimetry for Scattering Light using Wide Dynamic Range Intensity Detector

    Directory of Open Access Journals (Sweden)

    Shibata Shuhei

    2015-01-01

    Full Text Available This paper proposes a Stokes polarimetry for scattering light from a sample surface. To achieve a high accuracy measurement two approaches of an intensity detector and analysis algorism of a Stokes parameter were proposed. The dynamic range of this detector can achieve up to 1010 by combination of change of neutral-density (ND filters having different density and photon counting units. Stokes parameters can be measured by dual rotating of a retarder and an analyzer. The algorism of dual rotating polarimeter can be calibrated small linear diattenuation and linear retardance error of the retarder. This system can measured Stokes parameters from −20° to 70° of its scattering angle. It is possible to measure Stokes parameters of scattering of dust and scratch of optical device with high precision. This paper shows accuracy of this system, checking the polarization change of scattering angle and influence of beam size.

  13. Operation ranges and dynamic capabilities of variable-speed pumped-storage hydropower

    Science.gov (United States)

    Mercier, Thomas; Olivier, Mathieu; Dejaeger, Emmanuel

    2017-04-01

    The development of renewable and intermittent power generation creates incentives for the development of both energy storage solutions and more flexible power generation assets. Pumped-storage hydropower (PSH) is the most established and mature energy storage technology, but recent developments in power electronics have created a renewed interest by providing PSH units with a variable-speed feature, thereby increasing their flexibility. This paper reviews technical considerations related to variable-speed PSH in link with the provision of primary frequency control, also referred to as frequency containment reserves (FCRs). Based on the detailed characteristics of a scale model pump-turbine, the variable-speed operation ranges in pump and turbine modes are precisely assessed and the implications for the provision of FCRs are highlighted. Modelling and control for power system studies are discussed, both for fixed- and variable-speed machines and simulation results are provided to illustrate the high dynamic capabilities of variable-speed PSH.

  14. Endoscopic system for automated high dynamic range inspection of moving periodic structures

    Science.gov (United States)

    Hahlweg, Cornelius; Rothe, Hendrik

    2015-09-01

    In the current paper an advanced endoscopic system for high resolution and high dynamic range inspection of periodic structures in rotating machines is presented. We address the system architecture, short time illumination, special optical problems, such as excluding the specular reflex, image processing, forward velocity prediction and metrological image processing. There are several special requirements to be met, such as the thermal stability above 100°C, robustness of the image field, illumination in view direction and the separation of metallic surface diffuse scatter. To find a compromise between image resolution and frame rate, an external sensor system was applied for synchronization with the moving target. The system originally was intended for inspection of thermal engines, but turned out to be of a more general use. Beside the theoretical part and dimensioning issues, practical examples and measurement results are included.

  15. Predicting viscous-range velocity gradient dynamics in large-eddy simulations of turbulence

    Science.gov (United States)

    Johnson, Perry; Meneveau, Charles

    2017-11-01

    The details of small-scale turbulence are not directly accessible in large-eddy simulations (LES), posing a modeling challenge because many important micro-physical processes depend strongly on the dynamics of turbulence in the viscous range. Here, we introduce a method for coupling existing stochastic models for the Lagrangian evolution of the velocity gradient tensor with LES to simulate unresolved dynamics. The proposed approach is implemented in LES of turbulent channel flow and detailed comparisons with DNS are carried out. An application to modeling the fate of deformable, small (sub-Kolmogorov) droplets at negligible Stokes number and low volume fraction with one-way coupling is carried out. These results illustrate the ability of the proposed model to predict the influence of small scale turbulence on droplet micro-physics in the context of LES. This research was made possible by a graduate Fellowship from the National Science Foundation and by a Grant from The Gulf of Mexico Research Initiative.

  16. Extraordinary linear dynamic range in laser-defined functionalized graphene photodetectors

    Science.gov (United States)

    De Sanctis, Adolfo; Jones, Gareth F.; Wehenkel, Dominique J.; Bezares, Francisco; Koppens, Frank H. L.; Craciun, Monica F.; Russo, Saverio

    2017-01-01

    Graphene-based photodetectors have demonstrated mechanical flexibility, large operating bandwidth, and broadband spectral response. However, their linear dynamic range (LDR) is limited by graphene’s intrinsic hot-carrier dynamics, which causes deviation from a linear photoresponse at low incident powers. At the same time, multiplication of hot carriers causes the photoactive region to be smeared over distances of a few micrometers, limiting the use of graphene in high-resolution applications. We present a novel method for engineering photoactive junctions in FeCl3-intercalated graphene using laser irradiation. Photocurrent measured at these planar junctions shows an extraordinary linear response with an LDR value at least 4500 times larger than that of other graphene devices (44 dB) while maintaining high stability against environmental contamination without the need for encapsulation. The observed photoresponse is purely photovoltaic, demonstrating complete quenching of hot-carrier effects. These results pave the way toward the design of ultrathin photodetectors with unprecedented LDR for high-definition imaging and sensing. PMID:28560334

  17. Coherent Many-Body Spin Dynamics in a Long-Range Interacting Ising Chain

    Science.gov (United States)

    Zeiher, Johannes; Choi, Jae-yoon; Rubio-Abadal, Antonio; Pohl, Thomas; van Bijnen, Rick; Bloch, Immanuel; Gross, Christian

    2017-10-01

    Coherent many-body quantum dynamics lies at the heart of quantum simulation and quantum computation. Both require coherent evolution in the exponentially large Hilbert space of an interacting many-body system. To date, trapped ions have defined the state of the art in terms of achievable coherence times in interacting spin chains. Here, we establish an alternative platform by reporting on the observation of coherent, fully interaction-driven quantum revivals of the magnetization in Rydberg-dressed Ising spin chains of atoms trapped in an optical lattice. We identify partial many-body revivals at up to about ten times the characteristic time scale set by the interactions. At the same time, single-site-resolved correlation measurements link the magnetization dynamics with interspin correlations appearing at different distances during the evolution. These results mark an enabling step towards the implementation of Rydberg-atom-based quantum annealers, quantum simulations of higher-dimensional complex magnetic Hamiltonians, and itinerant long-range interacting quantum matter.

  18. An Adaptive Scheme for Robot Localization and Mapping with Dynamically Configurable Inter-Beacon Range Measurements

    Directory of Open Access Journals (Sweden)

    Arturo Torres-González

    2014-04-01

    Full Text Available This work is motivated by robot-sensor network cooperation techniques where sensor nodes (beacons are used as landmarks for range-only (RO simultaneous localization and mapping (SLAM. This paper presents a RO-SLAM scheme that actuates over the measurement gathering process using mechanisms that dynamically modify the rate and variety of measurements that are integrated in the SLAM filter. It includes a measurement gathering module that can be configured to collect direct robot-beacon and inter-beacon measurements with different inter-beacon depth levels and at different rates. It also includes a supervision module that monitors the SLAM performance and dynamically selects the measurement gathering configuration balancing SLAM accuracy and resource consumption. The proposed scheme has been applied to an extended Kalman filter SLAM with auxiliary particle filters for beacon initialization (PF-EKF SLAM and validated with experiments performed in the CONET Integrated Testbed. It achieved lower map and robot errors (34% and 14%, respectively than traditional methods with a lower computational burden (16% and similar beacon energy consumption.

  19. Improving the effectiveness of detailed processing by dynamic control of processing with high sports range

    Directory of Open Access Journals (Sweden)

    Yu.V. Shapoval

    2017-12-01

    Full Text Available In this article the possibility of increasing the efficiency of the processing of parts with a diameter of up to 20 mm is analyzed, namely: vibration resistance of the cutting process at pinching due to cutting speed control in the processing, forecasting and selection of rotational frequencies, which ensure the stability of the processing system, controlling the dynamics of the process of displacement of the additional mass. The method of investigation of vibration processes during the sharpening is developed. As a result of the processing of experimental data, it was found that when an oscillatory motion is applied to the spindle rotation, the overall level of oscillation decreases, which is reflected on the quality of the treated surface. The choice of a previously known spindle rotation frequency range at which the lowest value of the oscillation amplitude of the instrument is observed in the radial direction to the detail part, allows you to increase the processing efficiency while maintaining the drawing requirements for roughness by increasing the spindle rotational speed. The combination of the node of the own forms of oscillation and the cutting zone, by dynamically controlling the fluctuations of the lathe armature due to the increase of the inertia characteristics of the machine and the reduction of the oscillation amplitude of the tool, can improve the accuracy of machining and roughness of the processed surface of the component at higher spindle speeds.

  20. Multichannel emission spectrometer for high dynamic range optical pyrometry of shock-driven materials

    Science.gov (United States)

    Bassett, Will P.; Dlott, Dana D.

    2016-10-01

    An emission spectrometer (450-850 nm) using a high-throughput, high numerical aperture (N.A. = 0.3) prism spectrograph with stepped fiberoptic coupling, 32 fast photomultipliers and thirty-two 1.25 GHz digitizers is described. The spectrometer can capture single-shot events with a high dynamic range in amplitude and time (nanoseconds to milliseconds or longer). Methods to calibrate the spectrometer and verify its performance and accuracy are described. When a reference thermal source is used for calibration, the spectrometer can function as a fast optical pyrometer. Applications of the spectrometer are illustrated by using it to capture single-shot emission transients from energetic materials or reactive materials initiated by kmṡs-1 impacts with laser-driven flyer plates. A log (time) data analysis method is used to visualize multiple kinetic processes resulting from impact initiation of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) or a Zr/CuO nanolaminate thermite. Using a gray body algorithm to interpret the spectral radiance from shocked HMX, a time history of temperature and emissivity was obtained, which could be used to investigate HMX hot spot dynamics. Finally, two examples are presented showing how the spectrometer can avoid temperature determination errors in systems where thermal emission is accompanied by atomic or molecular emission lines.

  1. An LC-IMS-MS Platform Providing Increased Dynamic Range for High-Throughput Proteomic Studies

    Science.gov (United States)

    Baker, Erin Shammel; Livesay, Eric A.; Orton, Daniel J.; Moore, Ronald J.; Danielson, William F.; Prior, David C.; Ibrahim, Yehia M.; LaMarche, Brian L.; Mayampurath, Anoop M.; Schepmoes, Athena A.; Hopkins, Derek F.; Tang, Keqi; Smith, Richard D.; Belov, Mikhail E.

    2010-01-01

    A high-throughput approach and platform using 15 minute reversed-phase capillary liquid chromatography (RPLC) separations in conjunction with ion mobility spectrometry-mass spectrometry (IMS-MS) measurements was evaluated for the rapid analysis of complex proteomics samples. To test the separation quality of the short LC gradient, a sample was prepared by spiking twenty reference peptides at varying concentrations from 1 ng/mL to 10 µg/mL into a tryptic digest of mouse blood plasma and analyzed with both a LC-Linear Ion Trap Fourier Transform (FT) MS and LC-IMS-TOF MS. The LC-FT MS detected thirteen out of the twenty spiked peptides that had concentrations ≥100 ng/mL. In contrast, the drift time selected mass spectra from the LC-IMS-TOF MS analyses yielded identifications for nineteen of the twenty peptides with all spiking levels present. The greater dynamic range of the LC-IMS-TOF MS system could be attributed to two factors. First, the LC-IMS-TOF MS system enabled drift time separation of the low concentration spiked peptides from the high concentration mouse peptide matrix components, reducing signal interference and background, and allowing species to be resolved that would otherwise be obscured by other components. Second, the automatic gain control (AGC) in the linear ion trap of the hybrid FT MS instrument limits the number of ions that are accumulated to reduce space charge effects and achieve high measurement accuracy, but in turn limits the achievable dynamic range compared to the IMS-TOF instrument. PMID:20000344

  2. An LC-IMS-MS Platform Providing Increased Dynamic Range for High-Throughput Proteomic Studies

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Erin Shammel; Livesay, Eric A.; Orton, Daniel J.; Moore, Ronald J.; Danielson, William F.; Prior, David C.; Ibrahim, Yehia M.; Lamarche, Brian L.; Mayampurath, Anoop M.; Schepmoes, Athena A.; Hopkins, Derek F.; Tang, Keqi; Smith, Richard D.; Belov, Mikhail E.

    2010-02-05

    A high-throughput approach and platform using 15 minute reversed-phase capillary liquid chromatography (RPLC) separations in conjunction with ion mobility spectrometry-mass spectrometry (IMS-MS) measurements was evaluated for the rapid analysis of complex proteomics samples. To test the separation quality of the short LC gradient, a sample was prepared by spiking twenty reference peptides at varying concentrations from 1 ng/mL to 10 µg/mL into a tryptic digest of mouse blood plasma and analyzed with both a LC-Linear Ion Trap Fourier Transform (FT) MS and LC-IMS-TOF MS. The LC-FT MS detected thirteen out of the twenty spiked peptides that had concentrations ≥100 ng/mL. In contrast, the drift time selected mass spectra from the LC-IMS-TOF MS analyses yielded identifications for nineteen of the twenty peptides with all spiking level present. The greater dynamic range of the LC-IMS-TOF MS system could be attributed to two factors. First, the LC-IMS-TOF MS system enabled drift time separation of the low concentration spiked peptides from the high concentration mouse peptide matrix components, reducing signal interference and background, and allowing species to be resolved that would otherwise be obscured by other components. Second, the automatic gain control (AGC) in the linear ion trap of the hybrid FT MS instrument limits the number of ions that are accumulated to reduce space charge effects, but in turn limits the achievable dynamic range compared to the TOF detector.

  3. Statistical mechanics and dynamics of solvable models with long-range interactions

    International Nuclear Information System (INIS)

    Campa, Alessandro; Dauxois, Thierry; Ruffo, Stefano

    2009-01-01

    For systems with long-range interactions, the two-body potential decays at large distances as V(r)∼1/r α , with α≤d, where d is the space dimension. Examples are: gravitational systems, two-dimensional hydrodynamics, two-dimensional elasticity, charged and dipolar systems. Although such systems can be made extensive, they are intrinsically non additive: the sum of the energies of macroscopic subsystems is not equal to the energy of the whole system. Moreover, the space of accessible macroscopic thermodynamic parameters might be non convex. The violation of these two basic properties of the thermodynamics of short-range systems is at the origin of ensemble inequivalence. In turn, this inequivalence implies that specific heat can be negative in the microcanonical ensemble, and temperature jumps can appear at microcanonical first order phase transitions. The lack of convexity allows us to easily spot regions of parameter space where ergodicity may be broken. Historically, negative specific heat had been found for gravitational systems and was thought to be a specific property of a system for which the existence of standard equilibrium statistical mechanics itself was doubted. Realizing that such properties may be present for a wider class of systems has renewed the interest in long-range interactions. Here, we present a comprehensive review of the recent advances on the statistical mechanics and out-of-equilibrium dynamics of solvable systems with long-range interactions. The core of the review consists in the detailed presentation of the concept of ensemble inequivalence, as exemplified by the exact solution, in the microcanonical and canonical ensembles, of mean-field type models. Remarkably, the entropy of all these models can be obtained using the method of large deviations. Long-range interacting systems display an extremely slow relaxation towards thermodynamic equilibrium and, what is more striking, the convergence towards quasi-stationary states. The

  4. A low power, large dynamic range, CMOS amplifier and analog memory for capacitive sensors

    CERN Document Server

    Aspell, P; Bloch, P; Bourotte, J; Grabit, R; Jarron, Pierre; Reynaud, S; Van Hove, A; Zamiatin, N I

    1996-01-01

    This paper has been written to announce the design of a CMOS charge to voltage amplifier and it¹s integration within an analog memory. Together they provide the necessary front end electronics for the CMS electromagnetic calorimeter (ECAL) preshower detector systeAspell,Pm in the LHC experiment foreseen at the CERN particle physics laboratory. The design and measurements of the amplifier realised in a 1.5mm bulk CMOS process as a 16 channel prototype chip are presented. Results show the mean gain and peaking time of = 1.74mV/mip, = 18ns with channel to channel variations; s(peak_voltage) = 8% and s(peak_time) = 6.5%. The dynamic range is shown to be linear over 400mips with an integral non linearity (INL)=0.05mV as expressed in terms of sigma from the mean gain over the 400mip range. The measured noise of the amplifier was ENC=1800+41e/pF with a power consumption of 2.4mW/channel. The amplifier can support extreme levels of leakage current. The gain remains constant for up to 200mA of leakage current. The ...

  5. Exploring the dynamics of phase separation in colloid-polymer mixtures with long range attraction.

    Science.gov (United States)

    Sabin, Juan; Bailey, Arthur E; Frisken, Barbara J

    2016-06-28

    We have studied the kinetics of phase separation and gel formation in a low-dispersity colloid - non-adsorbing polymer system with long range attraction using small-angle light scattering. This system exhibits two-phase and three-phase coexistence of gas, liquid and crystal phases when the strength of attraction is between 2 and 4kBT and gel phases when the strength of attraction is increased. For those samples that undergo macroscopic phase separation, whether to gas-crystal, gas-liquid or gas-liquid-crystal coexistence, we observe dynamic scaling of the structure factor and growth of a characteristic length scale that behaves as expected for phase separation in fluids. In samples that gel, the power law associated with the growth of the dominant length scale is not equal to 1/3, but appears to depend mainly on the strength of attraction, decreasing from 1/3 for samples near the coexistence region to 1/27 at 8kBT, over a wide range of colloid and polymer concentrations.

  6. Secondary sympatry caused by range expansion informs on the dynamics of microendemism in a biodiversity hotspot.

    Directory of Open Access Journals (Sweden)

    Romain Nattier

    Full Text Available Islands are bounded areas where high endemism is explained either by allopatric speciation through the fragmentation of the limited amount of space available, or by sympatric speciation and accumulation of daughter species. Most empirical evidence point out the dominant action of allopatric speciation. We evaluate this general view by looking at a case study where sympatric speciation is suspected. We analyse the mode, tempo and geography of speciation in Agnotecous, a cricket genus endemic to New Caledonia showing a generalized pattern of sympatry between species making sympatric speciation plausible. We obtained five mitochondrial and five nuclear markers (6.8 kb from 37 taxa corresponding to 17 of the 21 known extant species of Agnotecous, and including several localities per species, and we conducted phylogenetic and dating analyses. Our results suggest that the diversification of Agnotecous occurred mostly through allopatric speciation in the last 10 Myr. Highly microendemic species are the most recent ones (<2 Myr and current sympatry is due to secondary range expansion after allopatric speciation. Species distribution should then be viewed as a highly dynamic process and extreme microendemism only as a temporary situation. We discuss these results considering the influence of climatic changes combined with intricate soil diversity and mountain topography. A complex interplay between these factors could have permitted repeated speciation events and range expansion.

  7. Touch HDR: photograph enhancement by user controlled wide dynamic range adaptation

    Science.gov (United States)

    Verrall, Steve; Siddiqui, Hasib; Atanassov, Kalin; Goma, Sergio; Ramachandra, Vikas

    2013-03-01

    High Dynamic Range (HDR) technology enables photographers to capture a greater range of tonal detail. HDR is typically used to bring out detail in a dark foreground object set against a bright background. HDR technologies include multi-frame HDR and single-frame HDR. Multi-frame HDR requires the combination of a sequence of images taken at different exposures. Single-frame HDR requires histogram equalization post-processing of a single image, a technique referred to as local tone mapping (LTM). Images generated using HDR technology can look less natural than their non- HDR counterparts. Sometimes it is only desired to enhance small regions of an original image. For example, it may be desired to enhance the tonal detail of one subject's face while preserving the original background. The Touch HDR technique described in this paper achieves these goals by enabling selective blending of HDR and non-HDR versions of the same image to create a hybrid image. The HDR version of the image can be generated by either multi-frame or single-frame HDR. Selective blending can be performed as a post-processing step, for example, as a feature of a photo editor application, at any time after the image has been captured. HDR and non-HDR blending is controlled by a weighting surface, which is configured by the user through a sequence of touches on a touchscreen.

  8. Low-complexity Compression of High Dynamic Range Infrared Images with JPEG compatibility

    DEFF Research Database (Denmark)

    Belyaev, Evgeny; Mantel, Claire; Forchhammer, Søren

    2017-01-01

    . Then we compress each image by a JPEG baseline encoder and include the residual image bit stream into the application part of JPEG header of the base image. As a result, the base image can be reconstructed by JPEG baseline decoder. If the JPEG bit stream size of the residual image is higher than the raw......We propose a low-complexity High Dynamic Range (HDR) infrared image (IR) coding algorithm assuming the typical case of IR images with an active range of more than 8 bit depth, but less than 16 bit depth. First, we separate an input image into base and residual images with maximum 8 bit depth each...... data size, then we include the raw residual image instead. If the residual image contains only zero values or the quality factor for it is 0 then we do not include the residual image into the header. Experimental results show that compared with JPEG-XT Part 6 with ’global Reinhard’ tone...

  9. Sensitivity of electrospray molecular dynamics simulations to long-range Coulomb interaction models

    Science.gov (United States)

    Mehta, Neil A.; Levin, Deborah A.

    2018-03-01

    Molecular dynamics (MD) electrospray simulations of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) ion liquid were performed with the goal of evaluating the influence of long-range Coulomb models on ion emission characteristics. The direct Coulomb (DC), shifted force Coulomb sum (SFCS), and particle-particle particle-mesh (PPPM) long-range Coulomb models were considered in this work. The DC method with a sufficiently large cutoff radius was found to be the most accurate approach for modeling electrosprays, but, it is computationally expensive. The Coulomb potential energy modeled by the DC method in combination with the radial electric fields were found to be necessary to generate the Taylor cone. The differences observed between the SFCS and the DC in terms of predicting the total ion emission suggest that the former should not be used in MD electrospray simulations. Furthermore, the common assumption of domain periodicity was observed to be detrimental to the accuracy of the capillary-based electrospray simulations.

  10. Long-range correlations and fractal dynamics in C. elegans: Changes with aging and stress

    Science.gov (United States)

    Alves, Luiz G. A.; Winter, Peter B.; Ferreira, Leonardo N.; Brielmann, Renée M.; Morimoto, Richard I.; Amaral, Luís A. N.

    2017-08-01

    Reduced motor control is one of the most frequent features associated with aging and disease. Nonlinear and fractal analyses have proved to be useful in investigating human physiological alterations with age and disease. Similar findings have not been established for any of the model organisms typically studied by biologists, though. If the physiology of a simpler model organism displays the same characteristics, this fact would open a new research window on the control mechanisms that organisms use to regulate physiological processes during aging and stress. Here, we use a recently introduced animal-tracking technology to simultaneously follow tens of Caenorhabdits elegans for several hours and use tools from fractal physiology to quantitatively evaluate the effects of aging and temperature stress on nematode motility. Similar to human physiological signals, scaling analysis reveals long-range correlations in numerous motility variables, fractal properties in behavioral shifts, and fluctuation dynamics over a wide range of timescales. These properties change as a result of a superposition of age and stress-related adaptive mechanisms that regulate motility.

  11. Low-complexity Compression of High Dynamic Range Infrared Images with JPEG compatibility

    DEFF Research Database (Denmark)

    Belyaev, Evgeny; Mantel, Claire; Forchhammer, Søren

    2017-01-01

    We propose a low-complexity High Dynamic Range (HDR) infrared image (IR) coding algorithm assuming the typical case of IR images with an active range of more than 8 bit depth, but less than 16 bit depth. First, we separate an input image into base and residual images with maximum 8 bit depth each....... Then we compress each image by a JPEG baseline encoder and include the residual image bit stream into the application part of JPEG header of the base image. As a result, the base image can be reconstructed by JPEG baseline decoder. If the JPEG bit stream size of the residual image is higher than the raw...... data size, then we include the raw residual image instead. If the residual image contains only zero values or the quality factor for it is 0 then we do not include the residual image into the header. Experimental results show that compared with JPEG-XT Part 6 with ’global Reinhard’ tone...

  12. High Dynamic Range adaptive ΔΣ-based Focal Plane Array architecture

    KAUST Repository

    Yao, Shun

    2012-10-16

    In this paper, an Adaptive Delta-Sigma based architecture for High Dynamic Range (HDR) Focal Plane Arrays is presented. The noise shaping effect of the Delta-Sigma modulation in the low end, and the distortion noise induced in the high end of Photo-diode current were analyzed in detail. The proposed architecture can extend the DR for about 20N log2 dB at the high end of Photo-diode current with an N bit Up-Down counter. At the low end, it can compensate for the larger readout noise by employing Extended Counting. The Adaptive Delta-Sigma architecture employing a 4-bit Up-Down counter achieved about 160dB in the DR, with a Peak SNR (PSNR) of 80dB at the high end. Compared to the other HDR architectures, the Adaptive Delta-Sigma based architecture provides the widest DR with the best SNR performance in the extended range.

  13. Shack-Hartmann centroid detection method based on high dynamic range imaging and normalization techniques

    International Nuclear Information System (INIS)

    Vargas, Javier; Gonzalez-Fernandez, Luis; Quiroga, Juan Antonio; Belenguer, Tomas

    2010-01-01

    In the optical quality measuring process of an optical system, including diamond-turning components, the use of a laser light source can produce an undesirable speckle effect in a Shack-Hartmann (SH) CCD sensor. This speckle noise can deteriorate the precision and accuracy of the wavefront sensor measurement. Here we present a SH centroid detection method founded on computer-based techniques and capable of measurement in the presence of strong speckle noise. The method extends the dynamic range imaging capabilities of the SH sensor through the use of a set of different CCD integration times. The resultant extended range spot map is normalized to accurately obtain the spot centroids. The proposed method has been applied to measure the optical quality of the main optical system (MOS) of the mid-infrared instrument telescope smulator. The wavefront at the exit of this optical system is affected by speckle noise when it is illuminated by a laser source and by air turbulence because it has a long back focal length (3017 mm). Using the proposed technique, the MOS wavefront error was measured and satisfactory results were obtained.

  14. A STEP TOWARDS DYNAMIC SCENE ANALYSIS WITH ACTIVE MULTI-VIEW RANGE IMAGING SYSTEMS

    Directory of Open Access Journals (Sweden)

    M. Weinmann

    2012-07-01

    Full Text Available Obtaining an appropriate 3D description of the local environment remains a challenging task in photogrammetric research. As terrestrial laser scanners (TLSs perform a highly accurate, but time-dependent spatial scanning of the local environment, they are only suited for capturing static scenes. In contrast, new types of active sensors provide the possibility of simultaneously capturing range and intensity information by images with a single measurement, and the high frame rate also allows for capturing dynamic scenes. However, due to the limited field of view, one observation is not sufficient to obtain a full scene coverage and therefore, typically, multiple observations are collected from different locations. This can be achieved by either placing several fixed sensors at different known locations or by using a moving sensor. In the latter case, the relation between different observations has to be estimated by using information extracted from the captured data and then, a limited field of view may lead to problems if there are too many moving objects within it. Hence, a moving sensor platform with multiple and coupled sensor devices offers the advantages of an extended field of view which results in a stabilized pose estimation, an improved registration of the recorded point clouds and an improved reconstruction of the scene. In this paper, a new experimental setup for investigating the potentials of such multi-view range imaging systems is presented which consists of a moving cable car equipped with two synchronized range imaging devices. The presented setup allows for monitoring in low altitudes and it is suitable for getting dynamic observations which might arise from moving cars or from moving pedestrians. Relying on both 3D geometry and 2D imagery, a reliable and fully automatic approach for co-registration of captured point cloud data is presented which is essential for a high quality of all subsequent tasks. The approach involves using

  15. Unattended real-time re-establishment of visibility in high dynamic range video and stills

    Science.gov (United States)

    Abidi, B.

    2014-05-01

    We describe a portable unattended persistent surveillance system that corrects for harsh illumination conditions, where bright sun light creates mixed contrast effects, i.e., heavy shadows and washouts. These effects result in high dynamic range scenes, where illuminance can vary from few luxes to a 6 figure value. When using regular monitors and cameras, such wide span of illuminations can only be visualized if the actual range of values is compressed, leading to the creation of saturated and/or dark noisy areas and a loss of information in these areas. Images containing extreme mixed contrast cannot be fully enhanced from a single exposure, simply because all information is not present in the original data. The active intervention in the acquisition process is required. A software package, capable of integrating multiple types of COTS and custom cameras, ranging from Unmanned Aerial Systems (UAS) data links to digital single-lens reflex cameras (DSLR), is described. Hardware and software are integrated via a novel smart data acquisition algorithm, which communicates to the camera the parameters that would maximize information content in the final processed scene. A fusion mechanism is then applied to the smartly acquired data, resulting in an enhanced scene where information in both dark and bright areas is revealed. Multi-threading and parallel processing are exploited to produce automatic real time full motion corrected video. A novel enhancement algorithm was also devised to process data from legacy and non-controllable cameras. The software accepts and processes pre-recorded sequences and stills, enhances visible, night vision, and Infrared data, and successfully applies to night time and dark scenes. Various user options are available, integrating custom functionalities of the application into intuitive and easy to use graphical interfaces. The ensuing increase in visibility in surveillance video and intelligence imagery will expand the performance and

  16. Dynamic dielectric analysis - A means for process control

    Science.gov (United States)

    Kranbuehl, D.; Delos, S.; Hoff, M.; Weller, L.

    1986-01-01

    The development of dynamic dielectric analysis techniques (as a 'smart' sensor for quantitative NDE) and of intelligent closed-loop cure systems is reported. The cure process of both BF3:R-catalyzed and uncatalyzed tetraglycidyl-4,4'-diaminodiphenyl methane (TGDDM)/diamine epoxy resins was studied. Measurements were made over a frequency range of six decades. The resin was monitored continuously throughout the cure process as it changed from a viscous liquid to a highly crosslinked solid. From the frequency dependence of the dielectric loss, the specific conductivity has been determined and shown to directly monitor the viscosity before the gel point is reached. Dielectric master plots of the cure process, analogous to time-temperature superposition plots for rheological data, have been developed.

  17. Robust tracking of respiratory rate in high-dynamic range scenes using mobile thermal imaging.

    Science.gov (United States)

    Cho, Youngjun; Julier, Simon J; Marquardt, Nicolai; Bianchi-Berthouze, Nadia

    2017-10-01

    The ability to monitor the respiratory rate, one of the vital signs, is extremely important for the medical treatment, healthcare and fitness sectors. In many situations, mobile methods, which allow users to undertake everyday activities, are required. However, current monitoring systems can be obtrusive, requiring users to wear respiration belts or nasal probes. Alternatively, contactless digital image sensor based remote-photoplethysmography (PPG) can be used. However, remote PPG requires an ambient source of light, and does not work properly in dark places or under varying lighting conditions. Recent advances in thermographic systems have shrunk their size, weight and cost, to the point where it is possible to create smart-phone based respiration rate monitoring devices that are not affected by lighting conditions. However, mobile thermal imaging is challenged in scenes with high thermal dynamic ranges (e.g. due to the different environmental temperature distributions indoors and outdoors). This challenge is further amplified by general problems such as motion artifacts and low spatial resolution, leading to unreliable breathing signals. In this paper, we propose a novel and robust approach for respiration tracking which compensates for the negative effects of variations in the ambient temperature and motion artifacts and can accurately extract breathing rates in highly dynamic thermal scenes. The approach is based on tracking the nostril of the user and using local temperature variations to infer inhalation and exhalation cycles. It has three main contributions. The first is a novel Optimal Quantization technique which adaptively constructs a color mapping of absolute temperature to improve segmentation, classification and tracking. The second is the Thermal Gradient Flow method that computes thermal gradient magnitude maps to enhance the accuracy of the nostril region tracking. Finally, we introduce the Thermal Voxel method to increase the reliability of the

  18. Which species will successfully track climate change? The influence of intraspecific competition and density dependent dispersal on range shifting dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Best, A.S.; Johst, K.; Muenkemueller, T.; Travis, J.M.J.

    2007-09-15

    Understanding the ability of species to shift their geographic range is of considerable importance given the current period of rapid climate change. Furthermore, a greater understanding of the spatial population dynamics underlying range shifting is required to complement the advances made in climate niche modelling. A simulation model is developed which incorporates three key features that have been largely overlooked in studies of range shifting dynamics: the form of intraspecific competition, density dependent dispersal and the transient dynamics of habitat patches. The results show that the exact shape of the response depends critically on both local and patch dynamics. Species whose intraspecific competition is contest based are more vulnerable than those whose competition is scramble based. Contesters are especially sensitive when combined with density dependent dispersal. Species living in patches whose carrying capacity grows slowly are also susceptible to rapid shifts of environmental conditions. A complementary analytic approach further highlights the importance of intraspecific competition. (au)

  19. Myosin-Va and Dynamic Actin Oppose Microtubules to Drive Long-Range Organelle Transport

    Science.gov (United States)

    Evans, Richard D.; Robinson, Christopher; Briggs, Deborah A.; Tooth, David J.; Ramalho, Jose S.; Cantero, Marta; Montoliu, Lluis; Patel, Shyamal; Sviderskaya, Elena V.; Hume, Alistair N.

    2014-01-01

    Summary In animal cells, microtubule and actin tracks and their associated motors (dynein, kinesin, and myosin) are thought to regulate long- and short-range transport, respectively [1–8]. Consistent with this, microtubules extend from the perinuclear centrosome to the plasma membrane and allow bidirectional cargo transport over long distances (>1 μm). In contrast, actin often comprises a complex network of short randomly oriented filaments, suggesting that myosin motors move cargo short distances. These observations underpin the “highways and local roads” model for transport along microtubule and actin tracks [2]. The “cooperative capture” model exemplifies this view and suggests that melanosome distribution in melanocyte dendrites is maintained by long-range transport on microtubules followed by actin/myosin-Va-dependent tethering [5, 9]. In this study, we used cell normalization technology to quantitatively examine the contribution of microtubules and actin/myosin-Va to organelle distribution in melanocytes. Surprisingly, our results indicate that microtubules are essential for centripetal, but not centrifugal, transport. Instead, we find that microtubules retard a centrifugal transport process that is dependent on myosin-Va and a population of dynamic F-actin. Functional analysis of mutant proteins indicates that myosin-Va works as a transporter dispersing melanosomes along actin tracks whose +/barbed ends are oriented toward the plasma membrane. Overall, our data highlight the role of myosin-Va and actin in transport, and not tethering, and suggest a new model in which organelle distribution is determined by the balance between microtubule-dependent centripetal and myosin-Va/actin-dependent centrifugal transport. These observations appear to be consistent with evidence coming from other systems showing that actin/myosin networks can drive long-distance organelle transport and positioning [10, 11]. PMID:25065759

  20. Integrated thermal and micro Coriolis flow sensing system with a dynamic flow range of more than 4 decades

    NARCIS (Netherlands)

    Lötters, Joost Conrad; Lammerink, Theodorus S.J.; Groenesteijn, Jarno; Haneveld, J.; Wiegerink, Remco J.

    2011-01-01

    We have realized a micromachined single chip flow sensing system with an unprecedented ultra-wide dynamic flow range of more than 4 decades, from less than 0.1 up to more than 1000 μl/h. The system comprises both a thermal and a micro Coriolis flow sensor with partially overlapping flow ranges.

  1. Spatially dynamic recurrent information flow across long-range dorsal motor network encodes selective motor goals.

    Science.gov (United States)

    Yoo, Peter E; Hagan, Maureen A; John, Sam E; Opie, Nicholas L; Ordidge, Roger J; O'Brien, Terence J; Oxley, Thomas J; Moffat, Bradford A; Wong, Yan T

    2018-03-08

    Performing voluntary movements involves many regions of the brain, but it is unknown how they work together to plan and execute specific movements. We recorded high-resolution ultra-high-field blood-oxygen-level-dependent signal during a cued ankle-dorsiflexion task. The spatiotemporal dynamics and the patterns of task-relevant information flow across the dorsal motor network were investigated. We show that task-relevant information appears and decays earlier in the higher order areas of the dorsal motor network then in the primary motor cortex. Furthermore, the results show that task-relevant information is encoded in general initially, and then selective goals are subsequently encoded in specifics subregions across the network. Importantly, the patterns of recurrent information flow across the network vary across different subregions depending on the goal. Recurrent information flow was observed across all higher order areas of the dorsal motor network in the subregions encoding for the current goal. In contrast, only the top-down information flow from the supplementary motor cortex to the frontoparietal regions, with weakened recurrent information flow between the frontoparietal regions and bottom-up information flow from the frontoparietal regions to the supplementary cortex were observed in the subregions encoding for the opposing goal. We conclude that selective motor goal encoding and execution rely on goal-dependent differences in subregional recurrent information flow patterns across the long-range dorsal motor network areas that exhibit graded functional specialization. © 2018 Wiley Periodicals, Inc.

  2. Dynamic magnetic susceptibility of systems with long-range magnetic order

    Energy Technology Data Exchange (ETDEWEB)

    Vannette, Matthew Dano [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    The utility of the TDR as an instrument in the study of magnetically ordered materials has been expanded beyond the simple demonstration purposes. Results of static applied magnetic field dependent measurements of the dynamic magnetic susceptibility, χ, of various ferromagnetic (FM) and antiferromagnetic (AFM) materials showing a range of transition temperatures (1-800 K) are presented. Data was collected primarily with a tunnel diode resonator (TDR) at different radio-frequencies (~10-30 MHz). In the vicinity of TC local moment ferromagnets show a very sharp, narrow peak in χ which is suppressed in amplitude and shifted to higher temperatures as the static bias field is increased. Unexpectedly, critical scaling analysis fails for these data. It is seen that these data are frequency dependent, however there is no simple method whereby measurement frequency can be changed in a controllable fashion. In contrast, itinerant ferromagnets show a broad maximum in χ well below TC which is suppressed and shifts to lower temperatures as the dc bias field is increased. The data on itinerant ferromagnets is fitted to a semi-phenomenological model that suggests the sample response is dominated by the uncompensated minority spins in the conduction band. Concluding remarks suggest possible scenarios to achieve frequency resolved data using the TDR as well as other fields in which the apparatus may be exploited.

  3. Snow cover dynamics and hydrological regime of the Hunza River basin, Karakoram Range, Northern Pakistan

    Directory of Open Access Journals (Sweden)

    A. A. Tahir

    2011-07-01

    Full Text Available A major proportion of flow in the Indus River is contributed by its snow- and glacier-fed river catchments situated in the Himalaya, Karakoram and Hindukush ranges. It is therefore essential to understand the cryosphere dynamics in this area for water resource management. The MODIS MOD10A2 remote-sensing database of snow cover products from March 2000 to December 2009 was selected to analyse the snow cover changes in the Hunza River basin (the snow- and glacier-fed sub-catchment of the Indus River. A database of daily flows for the Hunza River at Dainyor Bridge over a period of 40 yr and climate data (precipitation and temperature for 10 yr from three meteorological stations within the catchment was made available to investigate the hydrological regime in the area. Analysis of remotely sensed cryosphere (snow and ice cover data during the last decade (2000–2009 suggest a rather slight expansion of cryosphere in the area in contrast to most of the regions in the world where glaciers are melting rapidly. This increase in snow cover may be the result of an increase in winter precipitation caused by westerly circulation. The impact of global warming is not effective because a large part of the basin area lies under high altitudes where the temperature remains negative throughout most of the year.

  4. Flexible core masking technique for beam halo measurements with high dynamic range

    International Nuclear Information System (INIS)

    Egberts, J; Welsch, C P

    2010-01-01

    A thorough understanding of halo formation and its possible control is highly desirable for essentially all particle accelerators. Particles outside the beam core are not only lost for further experiments, they are also likely to hit the beam pipe, and activate this, as well as accelerator and experimental components in close proximity, which makes work on the accelerator costly and time consuming. Well established techniques for transverse beam profile measurements of electron or high energy hadron beams are the observation of synchrotron radiation, optical transition radiation or the like. A particular challenge, however, is the detection of particles in the tail regions of the beam distribution in close proximity of the very intense beam core. Results from laboratory measurements on two different devices are presented that might form the technical base of a future beam halo monitor: the novel SpectraCam XDR camera system which has an intrinsically high dynamic range due to its unique pixel design, and a flexible masking technique based on a DMD micro mirror array which allows for a fast mask generation to blank out the central core.

  5. Cascadia, an ultracompact seismic instrument with over 200dB of dynamic range

    Science.gov (United States)

    Parker, Tim; Devanney, Peter; Bainbridge, Geoff; Townsend, Bruce

    2017-04-01

    Integration of geophysical instrumentation is clearly a way to lower overall station cost, make installations less complex, reduce installation time, increase station utility and value to a wider group of researchers, data miners and monitoring groups. Initiatives to expand early earthquake warning networks and observatories can use these savings for increasing station density. Integration of mature instrument systems such as broadband sensors and accelerometers used in strong motion studies has to be done with care to preserve the low noise and low frequency performance while providing over 200dB of dynamic range. Understanding the instrument complexities and deployment challenges allows the engineering teams to optimize the packaging to make installation and servicing cost effective, simple, routine and ultimately more reliable. We discuss early results from testing both in the lab and in the field of a newly released instrument called the Cascadia that integrates a broadband seismometer with a class A (USGS rating) accelerometer in a small stainless steel sonde suited for dense arrays in either ad hoc direct bury field deployments or in observatory quality shallow boreholes.

  6. A High Dynamic Range Acousto-Optic Image Correlator For Real-Time Pattern Recognition

    Science.gov (United States)

    Money, Perry A.; Stalker, K. T.

    1988-08-01

    The architecture and experimental results for an incoherent acousto-optic image correlator suitable for real-time applications are presented. In the basic architecture, each time a line of the raster-scanned input image is fed into the acousto-optic device (AOD), all rows of a digitally stored reference image are read into the system using an array of light emitting diodes (LEDs). Thus, the required two-dimensional correlation is performed as a series of multi-channel 1-D time-integrations in x (performed in the AOD) combined with a multi-channel correlation in y (perpendicular to the AOD axis) using a modified CCD. The LED array and detector modifications which markedly increase the dynamic range are discussed as well as the correlator design. Further, a novel memory for storing the reference object is described for rapidly changing templates. Experimental results indicate the architecture is useful for applications in the areas of character recognition and target identification.

  7. Realization of High Dynamic Range Imaging in the GLORIA Network and Its Effect on Astronomical Measurement

    Directory of Open Access Journals (Sweden)

    Stanislav Vítek

    2016-01-01

    Full Text Available Citizen science project GLORIA (GLObal Robotic-telescopes Intelligent Array is a first free- and open-access network of robotic telescopes in the world. It provides a web-based environment where users can do research in astronomy by observing with robotic telescopes and/or by analyzing data that other users have acquired with GLORIA or from other free-access databases. Network of 17 telescopes allows users to control selected telescopes in real time or schedule any more demanding observation. This paper deals with new opportunity that GLORIA project provides to teachers and students of various levels of education. At the moment, there are prepared educational materials related to events like Sun eclipse (measuring local atmosphere changes, Aurora Borealis (calculation of Northern Lights height, or transit of Venus (measurement of the Earth-Sun distance. Student should be able to learn principles of CCD imaging, spectral analysis, basic calibration like dark frames subtraction, or advanced methods of noise suppression. Every user of the network can design his own experiment. We propose advanced experiment aimed at obtaining astronomical image data with high dynamic range. We also introduce methods of objective image quality evaluation in order to discover how HDR methods are affecting astronomical measurements.

  8. Utilizing multiple state variables to improve the dynamic range of analog switching in a memristor

    Science.gov (United States)

    Jeong, YeonJoo; Kim, Sungho; Lu, Wei D.

    2015-10-01

    Memristors and memristive systems have been extensively studied for data storage and computing applications such as neuromorphic systems. To act as synapses in neuromorphic systems, the memristor needs to exhibit analog resistive switching (RS) behavior with incremental conductance change. In this study, we show that the dynamic range of the analog RS behavior can be significantly enhanced in a tantalum-oxide-based memristor. By controlling different state variables enabled by different physical effects during the RS process, the gradual filament expansion stage can be selectively enhanced without strongly affecting the abrupt filament length growth stage. Detailed physics-based modeling further verified the observed experimental effects and revealed the roles of oxygen vacancy drift and diffusion processes, and how the diffusion process can be selectively enhanced during the filament expansion stage. These findings lead to more desirable and reliable memristor behaviors for analog computing applications. Additionally, the ability to selectively control different internal physical processes demonstrated in the current study provides guidance for continued device optimization of memristor devices in general.

  9. Carbon nanotube vacuum gauges with wide-dynamic range and processes thereof

    Science.gov (United States)

    Manohara, Harish (Inventor); Kaul, Anupama B. (Inventor)

    2013-01-01

    A miniature thermal conductivity gauge employs a carbon single-walled-nanotube. The gauge operates on the principle of thermal exchange between the voltage-biased nanotube and the surrounding gas at low levels of power and low temperatures to measure vacuum across a wide dynamic range. The gauge includes two terminals, a source of constant voltage to the terminals, a single-walled carbon nanotube between the terminals, a calibration of measured conductance of the nanotube to magnitudes of surrounding vacuum and a current meter in electrical communication with the source of constant voltage. Employment of the nanotube for measuring vacuum includes calibrating the electrical conductance of the nanotube to magnitudes of vacuum, exposing the nanotube to a vacuum, applying a constant voltage across the nanotube, measuring the electrical conductance of the nanotube in the vacuum with the constant voltage applied and converting the measured electrical conductance to the corresponding calibrated magnitude of vacuum using the calibration. The nanotube may be suspended to minimize heat dissipation through the substrate, increasing sensitivity at even tower pressures.

  10. Study of the vortex dynamics as a function of frequency in the microwave range

    Energy Technology Data Exchange (ETDEWEB)

    Sarti, S.; Silva, E.; Amabile, C.; Fastampa, R.; Giura, M

    2004-05-01

    The frequency dependence of the transport properties provides noticeable informations on the vortex matter in superconductors. In particular, low (<100 MHz) and high (of order 10 GHz) frequency response give different informations on the vortex dynamics: while at low frequency large distance motion of vortices is predominant, at higher frequencies vortices tend to oscillate around their equilibrium positions. Few reports have been presented in the past related to the study of the intermediate frequency regime, and to the evolution of one regime into the other. We present here an experimental study as a function of frequency, in the range 1-20 GHz, over a continuous frequency spectrum (Corbino disc technique), in presence of an applied magnetic field. Data are presented for both YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} and MgB{sub 2} superconductors. We also discuss the data as a function of frequency and show to what extent existing theories are able to fit the measured data.

  11. Sub-Airy disk angular resolution with high dynamic range in the near-infrared

    Directory of Open Access Journals (Sweden)

    Richichi A.

    2011-07-01

    Full Text Available Lunar occultations (LO are a simple and effective high angular resolution method, with minimum requirements in instrumentation and telescope time. They rely on the analysis of the diffraction fringes created by the lunar limb. The diffraction phenomen occurs in space, and as a result LO are highly insensitive to most of the degrading effects that limit the performance of traditional single telescope and long-baseline interferometric techniques used for direct detection of faint, close companions to bright stars. We present very recent results obtained with the technique of lunar occultations in the near-IR, showing the detection of companions with very high dynamic range as close as few milliarcseconds to the primary star. We discuss the potential improvements that could be made, to increase further the current performance. Of course, LO are fixed-time events applicable only to sources which happen to lie on the Moon’s apparent orbit. However, with the continuously increasing numbers of potential exoplanets and brown dwarfs beign discovered, the frequency of such events is not negligible. I will list some of the most favorable potential LO in the near future, to be observed from major observatories.

  12. Dynamic magnetic susceptibility of systems with long-range magnetic order

    International Nuclear Information System (INIS)

    Vannette, Matthew Dano

    2009-01-01

    The utility of the TDR as an instrument in the study of magnetically ordered materials has been expanded beyond the simple demonstration purposes. Results of static applied magnetic field dependent measurements of the dynamic magnetic susceptibility, ?, of various ferromagnetic (FM) and antiferromagnetic (AFM) materials showing a range of transition temperatures (1-800 K) are presented. Data was collected primarily with a tunnel diode resonator (TDR) at different radio-frequencies (∼10-30 MHz). In the vicinity of TC local moment ferromagnets show a very sharp, narrow peak in ? which is suppressed in amplitude and shifted to higher temperatures as the static bias field is increased. Unexpectedly, critical scaling analysis fails for these data. It is seen that these data are frequency dependent, however there is no simple method whereby measurement frequency can be changed in a controllable fashion. In contrast, itinerant ferromagnets show a broad maximum in ? well below TC which is suppressed and shifts to lower temperatures as the dc bias field is increased. The data on itinerant ferromagnets is fitted to a semi-phenomenological model that suggests the sample response is dominated by the uncompensated minority spins in the conduction band. Concluding remarks suggest possible scenarios to achieve frequency resolved data using the TDR as well as other fields in which the apparatus may be exploited.

  13. Increased Alpha-Rhythm Dynamic Range Promotes Recovery from Visuospatial Neglect: A Neurofeedback Study

    Directory of Open Access Journals (Sweden)

    Tomas Ros

    2017-01-01

    Full Text Available Despite recent attempts to use electroencephalogram (EEG neurofeedback (NFB as a tool for rehabilitation of motor stroke, its potential for improving neurological impairments of attention—such as visuospatial neglect—remains underexplored. It is also unclear to what extent changes in cortical oscillations contribute to the pathophysiology of neglect, or its recovery. Utilizing EEG-NFB, we sought to causally manipulate alpha oscillations in 5 right-hemisphere stroke patients in order to explore their role in visuospatial neglect. Patients trained to reduce alpha oscillations from their right posterior parietal cortex (rPPC for 20 minutes daily, over 6 days. Patients demonstrated successful NFB learning between training sessions, denoted by improved regulation of alpha oscillations from rPPC. We observed a significant negative correlation between visuospatial search deficits (i.e., cancellation test and reestablishment of spontaneous alpha-rhythm dynamic range (i.e., its amplitude variability. Our findings support the use of NFB as a tool for investigating neuroplastic recovery after stroke and suggest reinstatement of intact parietal alpha oscillations as a promising target for reversing attentional deficits. Specifically, we demonstrate for the first time the feasibility of EEG-NFB in neglect patients and provide evidence that targeting alpha amplitude variability might constitute a valuable marker for clinical symptoms and self-regulation.

  14. A Low-Power High-Dynamic-Range Receiver System for In-Probe 3-D Ultrasonic Imaging.

    Science.gov (United States)

    Attarzadeh, Hourieh; Xu, Ye; Ytterdal, Trond

    2017-10-01

    In this paper, a dual-mode low-power, high dynamic-range receiver circuit is designed for the interface with a capacitive micromachined ultrasonic transducer. The proposed ultrasound receiver chip enables the development of an in-probe digital beamforming imaging system. The flexibility of having two operation modes offers a high dynamic range with minimum power sacrifice. A prototype of the chip containing one receive channel, with one variable transimpedance amplifier (TIA) and one analog to digital converter (ADC) circuit is implemented. Combining variable gain TIA functionality with ADC gain settings achieves an enhanced overall high dynamic range, while low power dissipation is maintained. The chip is designed and fabricated in a 65 nm standard CMOS process technology. The test chip occupies an area of 76[Formula: see text] 170 [Formula: see text]. A total average power range of 60-240 [Formula: see text] for a sampling frequency of 30 MHz, and a center frequency of 5 MHz is measured. An instantaneous dynamic range of 50.5 dB with an overall dynamic range of 72 dB is obtained from the receiver circuit.

  15. Microspatial ecotone dynamics at a shifting range limit: plant-soil variation across salt marsh-mangrove interfaces.

    Science.gov (United States)

    Yando, E S; Osland, M J; Hester, M W

    2018-03-01

    Ecotone dynamics and shifting range limits can be used to advance our understanding of the ecological implications of future range expansions in response to climate change. In the northern Gulf of Mexico, the salt marsh-mangrove ecotone is an area where range limits and ecotone dynamics can be studied in tandem as recent decreases in winter temperature extremes have allowed for mangrove expansion at the expense of salt marsh. In this study, we assessed aboveground and belowground plant-soil dynamics across the salt marsh-mangrove ecotone quantifying micro-spatial patterns in horizontal extent. Specifically, we studied vegetation and rooting dynamics of large and small trees, the impact of salt marshes (e.g. species and structure) on mangroves, and the influence of vegetation on soil properties along transects from underneath the mangrove canopy into the surrounding salt marsh. Vegetation and rooting dynamics differed in horizontal reach, and there was a positive relationship between mangrove tree height and rooting extent. We found that the horizontal expansion of mangrove roots into salt marsh extended up to eight meters beyond the aboveground boundary. Variation in vegetation structure and local hydrology appear to control mangrove seedling dynamics. Finally, soil carbon density and organic matter did not differ within locations across the salt marsh-mangrove interface. By studying aboveground and belowground variation across the ecotone, we can better predict the ecological effects of continued range expansion in response to climate change.

  16. Microspatial ecotone dynamics at a shifting range limit: plant–soil variation across salt marsh–mangrove interfaces

    Science.gov (United States)

    Yando, Erik S.; Osland, Michael J.; Hester, Mark H.

    2018-01-01

    Ecotone dynamics and shifting range limits can be used to advance our understanding of the ecological implications of future range expansions in response to climate change. In the northern Gulf of Mexico, the salt marsh–mangrove ecotone is an area where range limits and ecotone dynamics can be studied in tandem as recent decreases in winter temperature extremes have allowed for mangrove expansion at the expense of salt marsh. In this study, we assessed aboveground and belowground plant–soil dynamics across the salt marsh–mangrove ecotone quantifying micro-spatial patterns in horizontal extent. Specifically, we studied vegetation and rooting dynamics of large and small trees, the impact of salt marshes (e.g. species and structure) on mangroves, and the influence of vegetation on soil properties along transects from underneath the mangrove canopy into the surrounding salt marsh. Vegetation and rooting dynamics differed in horizontal reach, and there was a positive relationship between mangrove tree height and rooting extent. We found that the horizontal expansion of mangrove roots into salt marsh extended up to eight meters beyond the aboveground boundary. Variation in vegetation structure and local hydrology appear to control mangrove seedling dynamics. Finally, soil carbon density and organic matter did not differ within locations across the salt marsh-mangrove interface. By studying aboveground and belowground variation across the ecotone, we can better predict the ecological effects of continued range expansion in response to climate change.

  17. EFFECTIVENESS OF ECCENTRIC TRAINING, DYNAMIC RANGE OF MOTION EXERCISES AND STATIC STRETCHING ON FLEXIBILITY OF HAMSTRING MUSCLE AMONG FOOTBALL PLAYERS.

    Directory of Open Access Journals (Sweden)

    Askar P.V

    2015-12-01

    Full Text Available Background: Hamstring stretch is an important part of treatment programs aimed at decreasing the likelihood of hamstring injury. Few studies have examine the effect of eccentric training, static stretching and dynamic range of motion(DROM exercise in improving hamstring flexibility this study compares the effect of eccentric training and static stretching in improving hamstring flexibility. The purpose of this study was to determine the effects of Eccentric training, Static stretching and Dynamic range of motion (DROM exercise in improving hamstring flexibility and the second objective is find which technique is more effective in improving hamstring flexibility when compared with a control group. Study design is Experimental pre-test post-test design. Methods: 88 male subjects with limited hamstring flexibility were recruited for this study were assigned to four group. Group1 received eccentric training, group2 received dynamic range of motion exercise, group3 received static stretching and group4 was served as control group. Hamstring length was measured pre intervention and post intervention using a self-monitored active knee extension test. Results: Eccentric training, static stretching and dynamic range of motion exercise showed a significant increase in hamstring length between pre and post intervention. Following a between group analysis done by independent t test revealed a significant difference between group1 group2 and group3 Conclusion: It is concluded that eccentric training, dynamic range of motion (DROM exercise and static stretching groups improved hamstring flexibility.

  18. Dynamic range compression in the honey bee auditory system toward waggle dance sounds.

    Directory of Open Access Journals (Sweden)

    Seiya Tsujiuchi

    2007-02-01

    Full Text Available Honey bee foragers use a "waggle dance" to inform nestmates about direction and distance to locations of attractive food. The sound and air flows generated by dancer's wing and abdominal vibrations have been implicated as important cues, but the decoding mechanisms for these dance messages are poorly understood. To understand the neural mechanisms of honey bee dance communication, we analyzed the anatomy of antenna and Johnston's organ (JO in the pedicel of the antenna, as well as the mechanical and neural response characteristics of antenna and JO to acoustic stimuli, respectively. The honey bee JO consists of about 300-320 scolopidia connected with about 48 cuticular "knobs" around the circumference of the pedicel. Each scolopidium contains bipolar sensory neurons with both type I and II cilia. The mechanical sensitivities of the antennal flagellum are specifically high in response to low but not high intensity stimuli of 265-350 Hz frequencies. The structural characteristics of antenna but not JO neurons seem to be responsible for the non-linear responses of the flagellum in contrast to mosquito and fruit fly. The honey bee flagellum is a sensitive movement detector responding to 20 nm tip displacement, which is comparable to female mosquito. Furthermore, the JO neurons have the ability to preserve both frequency and temporal information of acoustic stimuli including the "waggle dance" sound. Intriguingly, the response of JO neurons was found to be age-dependent, demonstrating that the dance communication is only possible between aged foragers. These results suggest that the matured honey bee antennae and JO neurons are best tuned to detect 250-300 Hz sound generated during "waggle dance" from the distance in a dark hive, and that sufficient responses of the JO neurons are obtained by reducing the mechanical sensitivity of the flagellum in a near-field of dancer. This nonlinear effect brings about dynamic range compression in the honey bee

  19. Comparison of three different concepts of high dynamic range and dependability optimised current measurement digitisers for beam loss systems

    CERN Document Server

    Viganò, W; Effinger, E; Venturini, G G; Zamantzas, C

    2012-01-01

    Three Different Concepts of High Dynamic Range and Dependability Optimised Current Measurement Digitisers for Beam Loss Systems will be compared on this paper. The first concept is based on Current to Frequency Conversion, enhanced with an ADC for extending the dynamic range and decreasing the response time. A summary of 3 years’ worth of operational experience with such a system for LHC beam loss monitoring will be given. The second principle is based on an Adaptive Current to Frequency Converter implemented in an ASIC. The basic parameters of the circuit are discussed and compared with measurements. Several measures are taken to harden both circuits against single event effects and to make them tolerant for operation in radioactive environments. The third circuit is based on a Fully Differential Integrator for enhanced dynamic range, where laboratory and test installation measurements will be presented. All circuits are designed to avoid any dead time in the acquisition and have reliability and fail safe...

  20. Smartphone-based accelerometry is a valid tool for measuring dynamic changes in knee extension range of motion

    DEFF Research Database (Denmark)

    Støve, Morten Pallisgaard; Palsson, Thorvaldur Skuli; Hirata, Rogerio Pessoto

    2018-01-01

    the validity of smartphone-based accelerometry measuring the dynamic range of motion of the knee joint during a passively executed extension movement.Materials and methodsDynamic knee extension range of motion was examined three consecutive times in twenty-one healthy male subjects utilising an isokinetic...... dynamometer to generate passively the extension motion. Measurements of joint angles in dynamic knee extension were performed using two methods: (i) isokinetic dynamometer (gold-standard method, Biodex System 4 Pro) and (ii) smartphone (iPhone 6, attached to the tibia) accelerometry data.......ResultsTests of validity showed excellent correlation (rs = 0.899) between methods, with a low standard error of measurement of 0.62 deg. and limits of agreement ranging from − 9.1 to 8.8 deg. Interclass correlation coefficients showed excellent between-measures reliability (ICC > 0.862) for both methods.ConclusionsSmartphone...

  1. Dynamics of Phosphorus export from small forested catchments in low mountain ranges in Germany

    Science.gov (United States)

    Julich, Stefan; Julich, Dorit; Benning, Raphael; Feger, Karl-Heinz

    2017-04-01

    Phosphorus (P) plays an important role in the nutrition of forest ecosystem. The transport of P in forest soils predominantly occurs along preferential water flow pathways bypassing large parts of the soil matrix. Therefore, rapid flow processes by preferential flow and/or during storm events may lead to significant P losses from forest soils. However only little knowledge about the dynamics, magnitude and driving processes of P exports into surface water exist. In this contribution, we present the results of two studies where two small forested catchments have been monitored for a period around 3 years. Both catchments are situated in low mountain ranges in Saxony (catchment size 21 ha) and Thuringia (catchment size 5 ha) representing medium P contents in the topsoil of 1142 mg kg-1 and 834 mg kg-1 respectively. During the regular sampling (monthly to weekly sampling frequency), the mean Total-P concentrations of 23 μg L-1(Thuringian Site) and 8 μg L-1(Saxonian Site) have been measured. However, during single storm events Total-P concentrations increased considerably with maximum concentrations of 134 μg L-1(Thuringian Site) and 203 μg L-1(Saxonian Site). Our findings indicate that during storm events, especially after longer dry periods, significant amounts of phosphorus can be exported from forest ecosystems. Comparison of discharge-concentration patterns of Total-P, Nitrogen and DOC, as well as dye tracer experiments, suggest that preferential flow along biopores and stone surfaces, and the interface between mineral soil and litter layer are main pathways of export from forests. For the site in Saxony we calculated mean annual export rates of 32.8 to 33.5 g ha-1 a-1 based on the weekly sampling with different load calculation methods (flow weighted methods up to linear regression models). If the events are included into the annual load calculation the mean annual export fluxes increase from 47.8 to 58.6 g ha-1 a-1 based on the different load calculation

  2. Study of the nonequilibrium critical quenching and the annealing dynamics for the long-range Ising model in one dimension

    International Nuclear Information System (INIS)

    Rodriguez, D E; Bab, M A; Albano, E V

    2011-01-01

    Extensive Monte Carlo simulations are employed in order to study the dynamic critical behaviour of the one-dimensional Ising magnet, with algebraically decaying long-range interactions of the form 1/r d+σ , with σ = 0.75. The critical temperature, as well as the critical exponents, are evaluated from the power-law behaviour of suitable physical observables when the system is quenched from uncorrelated states, corresponding to infinite temperature, to the critical point. These results are compared with those obtained from the dynamic evolution of the system when it is annealed at the critical point from the ordered state. Also, the critical temperature in the infinite interaction limit is obtained by means of a finite-range scaling analysis of data measured with different truncated interaction ranges. All the estimated static critical exponents (γ/ν, β/ν, and 1/ν) are in good agreement with renormalization group (RG) results and previously reported numerical data obtained under equilibrium conditions. On the other hand, the dynamic exponent of the initial increase of the magnetization (θ) was close to RG predictions. However, the dynamic exponent z of the time correlation length is slightly different to the RG results probably due to the fact that it may depend on the specific dynamics used or because the two-loop expansion used in the RG analysis may be insufficient

  3. Dynamic-range reduction by peak clipping or compression and its effects on phoneme perception in hearing-impaired listeners

    NARCIS (Netherlands)

    Dreschler, W. A.

    1988-01-01

    In this study, differences between dynamic-range reduction by peak clipping and single-channel compression for phoneme perception through conventional hearing aids have been investigated. The results from 16 hearing-impaired listeners show that compression limiting yields significantly better

  4. Multi-Bit Sigma-Delta Modulators with Enhanced Dynamic Range using Non-Linear DAC for Hearing Aids

    DEFF Research Database (Denmark)

    Custòdio, José; Paulino, Nuno; Goes, João

    2008-01-01

    This paper presents the possibility of employing non-linear low-resolution DACs in the feedback paths of multi-bit second-order Sigma-Delta modulators. The proposed technique is particularly attractive in applications such as hearing aids, requiring a very large dynamic range and medium signal-to...

  5. Intelligibility and Clarity of Reverberant Speech: Effects of Wide Dynamic Range Compression Release Time and Working Memory

    Science.gov (United States)

    Reinhart, Paul N.; Souza, Pamela E.

    2016-01-01

    Purpose: The purpose of this study was to examine the effects of varying wide dynamic range compression (WDRC) release time on intelligibility and clarity of reverberant speech. The study also considered the role of individual working memory. Method: Thirty older listeners with mild to moderately-severe sloping sensorineural hearing loss…

  6. Dynamic range of nanoresonators with random rough surfaces in the presence of thermomechanical and momentum exchange noise

    NARCIS (Netherlands)

    Palasantzas, G.

    2007-01-01

    The authors investigate the simultaneous influence of thermomechanical and momentum exchange noise on the linear dynamic range DR of nanoresonators with random rough surfaces. The latter are characterized by the roughness amplitude w, the lateral correlation length xi, and the roughness exponent 0

  7. Short-time dynamics of lysozyme solutions with competing short-range attraction and long-range repulsion: Experiment and theory

    Science.gov (United States)

    Riest, Jonas; Nägele, Gerhard; Liu, Yun; Wagner, Norman J.; Godfrin, P. Douglas

    2018-02-01

    Recently, atypical static features of microstructural ordering in low-salinity lysozyme protein solutions have been extensively explored experimentally and explained theoretically based on a short-range attractive plus long-range repulsive (SALR) interaction potential. However, the protein dynamics and the relationship to the atypical SALR structure remain to be demonstrated. Here, the applicability of semi-analytic theoretical methods predicting diffusion properties and viscosity in isotropic particle suspensions to low-salinity lysozyme protein solutions is tested. Using the interaction potential parameters previously obtained from static structure factor measurements, our results of Monte Carlo simulations representing seven experimental lysoyzme samples indicate that they exist either in dispersed fluid or random percolated states. The self-consistent Zerah-Hansen scheme is used to describe the static structure factor, S(q), which is the input to our calculation schemes for the short-time hydrodynamic function, H(q), and the zero-frequency viscosity η. The schemes account for hydrodynamic interactions included on an approximate level. Theoretical predictions for H(q) as a function of the wavenumber q quantitatively agree with experimental results at small protein concentrations obtained using neutron spin echo measurements. At higher concentrations, qualitative agreement is preserved although the calculated hydrodynamic functions are overestimated. We attribute the differences for higher concentrations and lower temperatures to translational-rotational diffusion coupling induced by the shape and interaction anisotropy of particles and clusters, patchiness of the lysozyme particle surfaces, and the intra-cluster dynamics, features not included in our simple globular particle model. The theoretical results for the solution viscosity, η, are in qualitative agreement with our experimental data even at higher concentrations. We demonstrate that semi

  8. Short-time dynamics of lysozyme solutions with competing short-range attraction and long-range repulsion: Experiment and theory.

    Science.gov (United States)

    Riest, Jonas; Nägele, Gerhard; Liu, Yun; Wagner, Norman J; Godfrin, P Douglas

    2018-02-14

    Recently, atypical static features of microstructural ordering in low-salinity lysozyme protein solutions have been extensively explored experimentally and explained theoretically based on a short-range attractive plus long-range repulsive (SALR) interaction potential. However, the protein dynamics and the relationship to the atypical SALR structure remain to be demonstrated. Here, the applicability of semi-analytic theoretical methods predicting diffusion properties and viscosity in isotropic particle suspensions to low-salinity lysozyme protein solutions is tested. Using the interaction potential parameters previously obtained from static structure factor measurements, our results of Monte Carlo simulations representing seven experimental lysoyzme samples indicate that they exist either in dispersed fluid or random percolated states. The self-consistent Zerah-Hansen scheme is used to describe the static structure factor, S(q), which is the input to our calculation schemes for the short-time hydrodynamic function, H(q), and the zero-frequency viscosity η. The schemes account for hydrodynamic interactions included on an approximate level. Theoretical predictions for H(q) as a function of the wavenumber q quantitatively agree with experimental results at small protein concentrations obtained using neutron spin echo measurements. At higher concentrations, qualitative agreement is preserved although the calculated hydrodynamic functions are overestimated. We attribute the differences for higher concentrations and lower temperatures to translational-rotational diffusion coupling induced by the shape and interaction anisotropy of particles and clusters, patchiness of the lysozyme particle surfaces, and the intra-cluster dynamics, features not included in our simple globular particle model. The theoretical results for the solution viscosity, η, are in qualitative agreement with our experimental data even at higher concentrations. We demonstrate that semi

  9. A wide dynamic range BF{sub 3} neutron monitor with front-end electronics based on a logarithmic amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Ferrarini, M., E-mail: michele.ferrarini@polimi.i [Politecnico di Milano, Dipartimento Energia, via G. Ponzio 34/3, I-20133 Milano (Italy); Fondazione CNAO, via Caminadella 16, 20123 Milano (Italy); Varoli, V. [Politecnico di Milano, Dipartimento Energia, via G. Ponzio 34/3, I-20133 Milano (Italy); Favalli, A. [European Commission, Joint Research Centre, Institute for the Protection and Security of Citizen, TP 800, Via E. Fermi, 21027 Ispra (Vatican City State, Holy See) (Italy); Caresana, M. [Politecnico di Milano, Dipartimento Energia, via G. Ponzio 34/3, I-20133 Milano (Italy); Pedersen, B. [European Commission, Joint Research Centre, Institute for the Protection and Security of Citizen, TP 800, Via E. Fermi, 21027 Ispra (Italy)

    2010-02-01

    This paper describes a wide dynamic range neutron monitor based on a BF{sub 3} neutron detector. The detector is used in current mode, and front-end electronics based on a logarithmic amplifier are used in order to have a measurement capability ranging over many orders of magnitude. The system has been calibrated at the Polytechnic of Milan, CESNEF, with an AmBe neutron source, and has been tested in a pulsed field at the PUNITA facility at JRC, Ispra. The detector has achieved a dynamic range of over 6 orders of magnitude, being able to measure single neutron pulses and showing saturation-free response for a reaction rate up to 10{sup 6} s{sup -1}. It has also proved effective in measuring the PUNITA facility pulse integral fluence.

  10. Neuronal long-range temporal correlations and avalanche dynamics are correlated with behavioral scaling laws

    NARCIS (Netherlands)

    Palva, M.J.; Zhigalov, A.; Hirvonen, J.; Korhonen, O.; Palva, S.; Linkenkaer-Hansen, K.

    2013-01-01

    Scale-free fluctuations are ubiquitous in behavioral performance and neuronal activity. In time scales from seconds to hundreds of seconds, psychophysical dynamics and the amplitude fluctuations of neuronal oscillations are governed by power-law-form longrange temporal correlations (LRTCs). In

  11. A design of an on-orbit radiometric calibration device for high dynamic range infrared remote sensors

    Science.gov (United States)

    Sheng, Yicheng; Jin, Weiqi; Dun, Xiong; Zhou, Feng; Xiao, Si

    2017-10-01

    With the demand of quantitative remote sensing technology growing, high reliability as well as high accuracy radiometric calibration technology, especially the on-orbit radiometric calibration device has become an essential orientation in term of quantitative remote sensing technology. In recent years, global launches of remote sensing satellites are equipped with innovative on-orbit radiometric calibration devices. In order to meet the requirements of covering a very wide dynamic range and no-shielding radiometric calibration system, we designed a projection-type radiometric calibration device for high dynamic range sensors based on the Schmidt telescope system. In this internal radiometric calibration device, we select the EF-8530 light source as the calibration blackbody. EF-8530 is a high emittance Nichrome (Ni-Cr) reference source. It can operate in steady or pulsed state mode at a peak temperature of 973K. The irradiance from the source was projected to the IRFPA. The irradiance needs to ensure that the IRFPA can obtain different amplitude of the uniform irradiance through the narrow IR passbands and cover the very wide dynamic range. Combining the internal on-orbit radiometric calibration device with the specially designed adaptive radiometric calibration algorithms, an on-orbit dynamic non-uniformity correction can be accomplished without blocking the optical beam from outside the telescope. The design optimizes optics, source design, and power supply electronics for irradiance accuracy and uniformity. The internal on-orbit radiometric calibration device not only satisfies a series of indexes such as stability, accuracy, large dynamic range and uniformity of irradiance, but also has the advantages of short heating and cooling time, small volume, lightweight, low power consumption and many other features. It can realize the fast and efficient relative radiometric calibration without shielding the field of view. The device can applied to the design and

  12. pVT-Second Virial Coefficients B(T ), Viscosity η(T ), and Self-Diffusion ρD(T) of the Gases: BF3, CF4, SiF4, CCl4, SiCl4, SF6, MoF6, WF6, UF6, C(CH3)4, and Si(CH3)4 Determined by Means of an Isotropic Temperature-Dependent Potential

    Science.gov (United States)

    Zarkova, L.; Hohm, U.

    2002-03-01

    We present results on self-consistent calculations of second pVT-virial coefficients B(T), viscosity data η(T), and diffusion coefficients ρD(T) for eleven heavy globular gases: boron trifluoride (BF3), carbon tetrafluoride (CF4), silicon tetrafluoride (SiF4), carbon tetrachloride (CCl4), silicon tetrachloride (SiCl4), sulfur hexafluoride (SF6), molybdenum hexafluoride (MoF6), tungsten hexafluoride (WF6), uranium hexafluoride (UF6), tetramethyl methane (C(CH3)4, TMM), and tetramethyl silane (Si(CH3)4, TMS). The calculations are performed mainly in the temperature range between 200 and 900 K by means of isotropic n-6 potentials with temperature-dependent separation rm(T) and potential well depth ɛ(T). The potential parameters at T=0 K (ɛ, rm, n) and the enlargement of the first level radii δ are obtained solving an ill-posed problem of minimizing the squared deviations between experimental and calculated values normalized to their relative experimental error. The temperature dependence of the potential is obtained as a result of the influence of vibrational excitation on binary interactions. This concept of the isotropic temperature-dependent potential (ITDP) is presented in detail where gaseous SF6 will serve as an example. The ITDP is subsequently applied to all other gases. This approach and the main part of the results presented here have already been published during 1996-2000. However, in some cases the data are upgraded due to the recently improved software (CF4, SF6) and newly found experimental data (CF4, SiF4, CCl4, SF6).

  13. High-sensitivity and large-dynamic-range refractive index sensors employing weak composite Fabry-Perot cavities.

    Science.gov (United States)

    Chen, Pengcheng; Shu, Xuewen; Cao, Haoran; Sugden, Kate

    2017-08-15

    Most sensors face a common trade-off between high sensitivity and a large dynamic range. We demonstrate here an all-fiber refractometer based on a dual-cavity Fabry-Perot interferometer (FPI) that possesses the advantage of both high sensitivity and a large dynamic range. Since the two composite cavities have a large cavity length difference, one can observe both fine and coarse fringes, which correspond to the long cavity and the short cavity, respectively. The short-cavity FPI and the use of an intensity demodulation method mean that the individual fine fringe dips correspond to a series of quasi-continuous highly sensitive zones for refractive index measurement. By calculating the parameters of the composite FPI, we find that the range of the ultra-sensitive zones can be considerably adjusted to suit the end requirements. The experimental trends are in good agreement with the theoretical predictions. The co-existence of high sensitivity and a large dynamic range in a composite FPI is of great significance to practical RI measurements.

  14. Effects of population reduction on white-tailed deer home-range dynamics

    Science.gov (United States)

    Crimmins, Shawn M.; Edwards, John W.; Campbell, Tyler A; Ford, W. Mark; Keyser, Patrick D.; Miller, Brad F.; Miller, Karl V.

    2015-01-01

    Management strategies designed to reduce the negative impacts of overabundant Odocoileus virginianus (White-tailed Deer) populations on forest regeneration may be influenced by changes in both population density and timber harvest. However, there is conflicting evidence as to how such changes in per capita resource availability influence home-range patterns. We compared home-range patterns of 33 female White-tailed Deer from a low-density population at a site with abundant browse to patterns of a sample of >100 females prior to a 75% reduction in population density and a doubling in timber harvest area. Home-range and core-area sizes were approximately 3 times larger than were found prior to population decline and timber harvest increase, consistent with predictions related to intraspecific competition. We also observed greater site fidelity than previously exhibited, although this may be an artifact of increased home-range sizes. Our results support previous research suggesting that White-tailed Deer home-range size is inversely related to population density and is driven, in part, by intraspecific competition for resources. Relationships among population density, resource availability, and home-range patterns among female White-tailed Deer appear to be complex and context specific.

  15. The effects of food sources on Japanese monkey home range size and location, and population dynamics.

    Science.gov (United States)

    Koganezawa, M; Imaki, H

    1999-01-01

    The effects of supplemental feeding by tourists on wild Japanese monkey's home range size and location, and troop size and composition were studied for two monkey troops, Troop A and Troop B, living along the Irohazaka loop road, Nikko National Park, central Japan. Changes were documented based on data gathered from 1982 to 1996 by the use of radio telemetry. Troop A's home range size shrank and changed from separate winter and summer ranges to a single, year-round home range, with its core located in a high elevation area where supplemental feeding by tourists was heavy. Troop B's home range also shrank and shifted to a lower elevation where supplemental feeding by tourists was heavy. Troop A's population size increased between the winters of 1983-1984 and 1990-1991 in conjunction with an increase in human encounter rates, and then decreased. Troop B's size increased until the winter of 1993-1994, and then decreased. The instability of troop size between 1993 and 1996 may be explained by documented factors such as a decrease in the adult sex ratio, an increase in the infant-female ratio, and an increase in juvenile mortality and/or emigration, all of which may have been influenced by supplemental feeding by tourists.

  16. Short-range order and collective dynamics of DMPC bilayers: a comparison between molecular dynamics simulations, X-ray, and neutron scattering experiments.

    Science.gov (United States)

    Hub, Jochen S; Salditt, Tim; Rheinstädter, Maikel C; de Groot, Bert L

    2007-11-01

    We present an extensive comparison of short-range order and short wavelength dynamics of a hydrated phospholipid bilayer derived by molecular dynamics simulations, elastic x-ray, and inelastic neutron scattering experiments. The quantities that are compared between simulation and experiment include static and dynamic structure factors, reciprocal space mappings, and electron density profiles. We show that the simultaneous use of molecular dynamics and diffraction data can help to extract real space properties like the area per lipid and the lipid chain ordering from experimental data. In addition, we assert that the interchain distance can be computed to high accuracy from the interchain correlation peak of the structure factor. Moreover, it is found that the position of the interchain correlation peak is not affected by the area per lipid, while its correlation length decreases linearly with the area per lipid. This finding allows us to relate a property of the structure factor quantitatively to the area per lipid. Finally, the short wavelength dynamics obtained from the simulations and from inelastic neutron scattering are analyzed and compared. The conventional interpretation in terms of the three-effective-eigenmode model is found to be only partly suitable to describe the complex fluid dynamics of lipid chains.

  17. Light detection and ranging measurements of wake dynamics. Part II: two-dimensional scanning

    DEFF Research Database (Denmark)

    Trujillo, Juan-José; Bingöl, Ferhat; Larsen, Gunner Chr.

    2011-01-01

    the instantaneous transversal wake position which is quantitatively compared with the prediction of the Dynamic Wake Meandering model. The results, shown for two 10-min time series, suggest that the conjecture of the wake behaving as a passive tracer is a fair approximation; this corroborates and expands...... the results of one-dimensional measurements already presented in the first part of this paper. Consequently, it is now possible to separate the deterministic and turbulent parts of the wake wind field, thus enabling capturing the wake in the meandering frame of reference. The results correspond, qualitatively...

  18. Combining short- and long-range fluorescence reporters with simulations to explore the intramolecular dynamics of an intrinsically disordered protein

    Science.gov (United States)

    Zosel, Franziska; Haenni, Dominik; Soranno, Andrea; Nettels, Daniel; Schuler, Benjamin

    2017-10-01

    Intrinsically disordered proteins (IDPs) are increasingly recognized as a class of molecules that can exert essential biological functions even in the absence of a well-defined three-dimensional structure. Understanding the conformational distributions and dynamics of these highly flexible proteins is thus essential for explaining the molecular mechanisms underlying their function. Single-molecule fluorescence spectroscopy in combination with Förster resonance energy transfer (FRET) is a powerful tool for probing intramolecular distances and the rapid long-range distance dynamics in IDPs. To complement the information from FRET, we combine it with photoinduced electron transfer (PET) quenching to monitor local loop-closure kinetics at the same time and in the same molecule. Here we employed this combination to investigate the intrinsically disordered N-terminal domain of HIV-1 integrase. The results show that both long-range dynamics and loop closure kinetics on the sub-microsecond time scale can be obtained reliably from a single set of measurements by the analysis with a comprehensive model of the underlying photon statistics including both FRET and PET. A more detailed molecular interpretation of the results is enabled by direct comparison with a recent extensive atomistic molecular dynamics simulation of integrase. The simulations are in good agreement with experiment and can explain the deviation from simple models of chain dynamics by the formation of persistent local secondary structure. The results illustrate the power of a close combination of single-molecule spectroscopy and simulations for advancing our understanding of the dynamics and detailed mechanisms in unfolded and intrinsically disordered proteins.

  19. Flat panel X-ray detector with reduced internal scattering for improved attenuation accuracy and dynamic range

    Science.gov (United States)

    Smith, Peter D [Santa Fe, NM; Claytor, Thomas N [White Rock, NM; Berry, Phillip C [Albuquerque, NM; Hills, Charles R [Los Alamos, NM

    2010-10-12

    An x-ray detector is disclosed that has had all unnecessary material removed from the x-ray beam path, and all of the remaining material in the beam path made as light and as low in atomic number as possible. The resulting detector is essentially transparent to x-rays and, thus, has greatly reduced internal scatter. The result of this is that x-ray attenuation data measured for the object under examination are much more accurate and have an increased dynamic range. The benefits of this improvement are that beam hardening corrections can be made accurately, that computed tomography reconstructions can be used for quantitative determination of material properties including density and atomic number, and that lower exposures may be possible as a result of the increased dynamic range.

  20. Combining Density Functional Theory and Green's Function Theory: Range-Separated, Nonlocal, Dynamic, and Orbital-Dependent Hybrid Functional.

    Science.gov (United States)

    Kananenka, Alexei A; Zgid, Dominika

    2017-11-14

    We present a rigorous framework which combines single-particle Green's function theory with density functional theory based on a separation of electron-electron interactions into short- and long-range components. Short-range contribution to the total energy and exchange-correlation potential is provided by a density functional approximation, while the long-range contribution is calculated using an explicit many-body Green's function method. Such a hybrid results in a nonlocal, dynamic, and orbital-dependent exchange-correlation functional of a single-particle Green's function. In particular, we present a range-separated hybrid functional called srSVWN5-lrGF2 which combines the local-density approximation and the second-order Green's function theory. We illustrate that similarly to density functional approximations, the new functional is weakly basis-set dependent. Furthermore, it offers an improved description of the short-range dynamic correlation. The many-body contribution to the functional mitigates the many-electron self-interaction error present in many density functional approximations and provides a better description of molecular properties. Additionally, we illustrate that the new functional can be used to scale down the self-energy and, therefore, introduce an additional sparsity to the self-energy matrix that in the future can be exploited in calculations for large molecules or periodic systems.

  1. Statistical-dynamical long-range seasonal forecasting of streamflow with the North-American Multi Model Ensemble (NMME)

    Science.gov (United States)

    Slater, Louise; Villarini, Gabriele

    2017-04-01

    There are two main approaches to long-range (monthly to seasonal) streamflow forecasting: statistical approaches that typically relate climate precursors directly to streamflow, and dynamical physically-based approaches in which spatially distributed models are forced with downscaled meteorological forecasts. While the former approach is potentially limited by a lack of physical causality, the latter tends to be complex and time-consuming to implement. In contrast, hybrid statistical-dynamical techniques that use global climate model (GCM) ensemble forecasts as inputs to statistical models are both physically-based and rapid to run, but are a relatively new field of research. Here, we conduct the first systematic multimodel statistical-dynamical forecasting of streamflow using NMME climate forecasts from eight GCMs (CCSM3, CCSM4, CanCM3, CanCM4, GFDL2.1, FLORb01, GEOS5, and CFSv2) across a broad region. At several hundred U.S. Midwest stream gauges with long (50+ continuous years) streamflow records, we fit probabilistic statistical models for seasonal streamflow percentiles ranging from minimum to maximum flows. As predictors, we use basin-averaged values of precipitation, antecedent wetness, temperature, agricultural row crop acreage, and population density. Using the observed data, we select the best-fitting probabilistic model for every site, season, and streamflow percentile (ranging from low to high flows). The best-fitting models are then used to obtain streamflow predictions by incorporating the NMME climate forecasts and the extrapolated agricultural and population time series as predictors. The forecasting skill of our models is assessed using both deterministic and probabilistic verification measures. The influence of the different predictors is evaluated for all streamflow percentiles and across the full range of lead times. Our findings reveal that statistical-dynamical streamflow forecasting produces promising results, which may enable water managers

  2. The Effect of a Period Stretching Training on Functional Dynamic Balance Performance and Range of Motion Patients with Knee Osteoarthritis

    OpenAIRE

    Edris Bavardi Moghadam; Seyed Sadradin Shojaedin

    2017-01-01

    Objective: This study was done to investigate the effect of a period of stretch training on functional dynamic balance performance and range of motion in patients with knee osteoarthritis. Methods: the population from which the sample of the study was selected included active older men with knee osteoarthritis in West Azerbaijan. 20 active man who were paid to exercise at least twice a week, were randomly divided into two groups of 10 patients. Subjects for 8 weeks, three times a week. To ...

  3. EFFECTIVENESS OF ECCENTRIC TRAINING, DYNAMIC RANGE OF MOTION EXERCISES AND STATIC STRETCHING ON FLEXIBILITY OF HAMSTRING MUSCLE AMONG FOOTBALL PLAYERS.

    OpenAIRE

    Askar P.V; Veena Pais; Nagarajan Mohan; Shaikhji Saad; Nusaibath M Shaikhji

    2015-01-01

    Background: Hamstring stretch is an important part of treatment programs aimed at decreasing the likelihood of hamstring injury. Few studies have examine the effect of eccentric training, static stretching and dynamic range of motion(DROM) exercise in improving hamstring flexibility this study compares the effect of eccentric training and static stretching in improving hamstring flexibility. The purpose of this study was to determine the effects of Eccentric training, Static stretching and Dy...

  4. How do parcellation size and short-range connectivity affect dynamics in large-scale brain network models?

    Science.gov (United States)

    Proix, Timothée; Spiegler, Andreas; Schirner, Michael; Rothmeier, Simon; Ritter, Petra; Jirsa, Viktor K

    2016-11-15

    Recent efforts to model human brain activity on the scale of the whole brain rest on connectivity estimates of large-scale networks derived from diffusion magnetic resonance imaging (dMRI). This type of connectivity describes white matter fiber tracts. The number of short-range cortico-cortical white-matter connections is, however, underrepresented in such large-scale brain models. It is still unclear on the one hand, which scale of representation of white matter fibers is optimal to describe brain activity on a large-scale such as recorded with magneto- or electroencephalography (M/EEG) or functional magnetic resonance imaging (fMRI), and on the other hand, to which extent short-range connections that are typically local should be taken into account. In this article we quantified the effect of connectivity upon large-scale brain network dynamics by (i) systematically varying the number of brain regions before computing the connectivity matrix, and by (ii) adding generic short-range connections. We used dMRI data from the Human Connectome Project. We developed a suite of preprocessing modules called SCRIPTS to prepare these imaging data for The Virtual Brain, a neuroinformatics platform for large-scale brain modeling and simulations. We performed simulations under different connectivity conditions and quantified the spatiotemporal dynamics in terms of Shannon Entropy, dwell time and Principal Component Analysis. For the reconstructed connectivity, our results show that the major white matter fiber bundles play an important role in shaping slow dynamics in large-scale brain networks (e.g. in fMRI). Faster dynamics such as gamma oscillations (around 40 Hz) are sensitive to the short-range connectivity if transmission delays are considered. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. High-dynamic range image projection using an auxiliary MEMS mirror array.

    Science.gov (United States)

    Hoskinson, Reynald; Stoeber, Boris

    2008-05-12

    We introduce a new concept to improve the contrast and peak brightness of conventional data projectors. Our method provides a non-homogenous light source by dynamically directing fractions of the light from the projector lamp before it reaches the display mechanism. This will supply more light to the areas that need it most, at the expense of the darker parts of the image. In effect, this method will produce a low resolution version of the image onto the image-forming element. To manipulate the light in this manner, we propose using an intermediate array of microelectromechanical system (MEMS) mirrors. By directing the light away from the dark parts earlier in the display chain, the amount of light that needs to be blocked will be reduced, thus decreasing the black level of the final image. Moreover, the ability to dynamically allocate more light to the bright parts of the image will allow for peak brightness higher than the average maximum brightness of display.

  6. Long-Range Correlations and Memory in the Dynamics of Internet Interdomain Routing.

    Directory of Open Access Journals (Sweden)

    Maksim Kitsak

    Full Text Available Data transfer is one of the main functions of the Internet. The Internet consists of a large number of interconnected subnetworks or domains, known as Autonomous Systems (ASes. Due to privacy and other reasons the information about what route to use to reach devices within other ASes is not readily available to any given AS. The Border Gateway Protocol (BGP is responsible for discovering and distributing this reachability information to all ASes. Since the topology of the Internet is highly dynamic, all ASes constantly exchange and update this reachability information in small chunks, known as routing control packets or BGP updates. In the view of the quick growth of the Internet there are significant concerns with the scalability of the BGP updates and the efficiency of the BGP routing in general. Motivated by these issues we conduct a systematic time series analysis of BGP update rates. We find that BGP update time series are extremely volatile, exhibit long-term correlations and memory effects, similar to seismic time series, or temperature and stock market price fluctuations. The presented statistical characterization of BGP update dynamics could serve as a basis for validation of existing and developing better models of Internet interdomain routing.

  7. Atmospheric dynamics and habitability range in Earth-like aquaplanets obliquity simulations

    Science.gov (United States)

    Nowajewski, Priscilla; Rojas, M.; Rojo, P.; Kimeswenger, S.

    2018-05-01

    We present the evolution of the atmospheric variables that affect planetary climate by increasing the obliquity by using a general circulation model (PlaSim) coupled to a slab ocean with mixed layer flux correction. We increase the obliquity between 30° and 90° in 16 aquaplanets with liquid sea surface and perform the simulation allowing the sea ice cover formation to be a consequence of its atmospheric dynamics. Insolation is maintained constant in each experiment, but changing the obliquity affects the radiation budget and the large scale circulation. Earth-like atmospheric dynamics is observed for planets with obliquity under 54°. Above this value, the latitudinal temperature gradient is reversed giving place to a new regime of jet streams, affecting the shape of Hadley and Ferrel cells and changing the position of the InterTropical Convergence Zone. As humidity and high temperatures determine Earth's habitability, we introduce the wet bulb temperature as an atmospheric index of habitability for Earth-like aquaplanets with above freezing temperatures. The aquaplanets are habitable all year round at all latitudes for values under 54°; above this value habitability decreases toward the poles due to high temperatures.

  8. pain, range of motion and activity level as correlates of dynamic ...

    African Journals Online (AJOL)

    2014-12-01

    Dec 1, 2014 ... Objective: To determine the influence of pain, hip range of motion ... derly patients was considerably influenced by pain, hip flexibility and level of ..... ics of turning: limb asymmetries associated with walking a circular path. Gait Posture. 2006 Feb;. 23:106-111. 10. Simpson JM, Worsfold C, Reilly E,. Nye NA.

  9. Range and variation in landscape patch dynamics: Implications for ecosystem management

    Science.gov (United States)

    Robert E. Keane; Janice L. Garner; Casey Teske; Cathy Stewart; Paul Hessburg

    2001-01-01

    Northern Rocky Mountain landscape patterns are shaped primarily by fire and succession, and conversely, these vegetation patterns influence burning patterns and plant colonization processes. Historical range and variability (HRV) of landscape pattern can be quantified from three sources: (1) historical chronosequences, (2) spatial series, and (3) simulated...

  10. Quantum correlation dynamics subjected to critical spin environment with short-range anisotropic interaction.

    Science.gov (United States)

    Guo, J L; Zhang, X Z

    2016-09-06

    Short-range interaction among the spins can not only results in the rich phase diagram but also brings about fascinating phenomenon both in the contexts of quantum computing and information. In this paper, we investigate the quantum correlation of the system coupled to a surrounding environment with short-range anisotropic interaction. It is shown that the decay of quantum correlation of the central spins measured by pairwise entanglement and quantum discord can serve as a signature of quantum phase transition. In addition, we study the decoherence factor of the system when the environment is in the vicinity of the phase transition point. In the strong coupling regime, the decay of the decoherence factor exhibits Gaussian envelop in the time domain. However, in weak coupling limit, the quantum correlation of the system is robust against the disturbance of the magnetic field through optimal control of the anisotropic short-range interaction strength. Based on this, the effects of the short-range anisotropic interaction on the sudden transition from classical to quantum decoherence are also presented.

  11. Determining Occurrence Dynamics when False Positives Occur: Estimating the Range Dynamics of Wolves from Public Survey Data.

    Science.gov (United States)

    Miller, David A W; Nichols, James D; Gude, Justin A; Rich, Lindsey N; Podruzny, Kevin M; Hines, James E; Mitchell, Michael S

    2013-01-01

    Large-scale presence-absence monitoring programs have great promise for many conservation applications. Their value can be limited by potential incorrect inferences owing to observational errors, especially when data are collected by the public. To combat this, previous analytical methods have focused on addressing non-detection from public survey data. Misclassification errors have received less attention but are also likely to be a common component of public surveys, as well as many other data types. We derive estimators for dynamic occupancy parameters (extinction and colonization), focusing on the case where certainty can be assumed for a subset of detections. We demonstrate how to simultaneously account for non-detection (false negatives) and misclassification (false positives) when estimating occurrence parameters for gray wolves in northern Montana from 2007-2010. Our primary data source for the analysis was observations by deer and elk hunters, reported as part of the state's annual hunter survey. This data was supplemented with data from known locations of radio-collared wolves. We found that occupancy was relatively stable during the years of the study and wolves were largely restricted to the highest quality habitats in the study area. Transitions in the occupancy status of sites were rare, as occupied sites almost always remained occupied and unoccupied sites remained unoccupied. Failing to account for false positives led to over estimation of both the area inhabited by wolves and the frequency of turnover. The ability to properly account for both false negatives and false positives is an important step to improve inferences for conservation from large-scale public surveys. The approach we propose will improve our understanding of the status of wolf populations and is relevant to many other data types where false positives are a component of observations.

  12. Altitudinal dynamics of glacial lakes under changing climate in the Hindu Kush, Karakoram, and Himalaya ranges

    Science.gov (United States)

    Ashraf, Arshad; Naz, Rozina; Iqbal, Muhammad Bilal

    2017-04-01

    The environmental challenges posed by global warming in the Himalayan region include early and rapid melting of snow and glaciers, creation of new lakes, and expansion of old ones posing a high risk of glacial lakes outburst flood (GLOF) hazard for downstream communities. According to various elevation ranges, 3044 lakes were analyzed basinwide in the Hindu Kush-Karakoram-Himalaya (HKH) ranges of Pakistan using multisensor remote sensing data of the 2001-2013 period. An overall increase in glacial lakes was observed at various altitudinal ranges between 2500 and 5500, m out of which noticeable change by number was within the 4000-4500 m range. The analysis carried out by glacial-fed lakes and nonglacial-fed lakes in different river basins indicated variable patterns depending on the geographic location in the HKH region. The correlation analysis of parameters like lake area, expansion rate, and elevation was performed with 617 glacial lakes distributed in various river basins of the three HKH ranges. Lake area (2013) and elevation showed a negative relationship for all basins except Hunza, Shigar, and Shyok. The correlation between the expansion rate of lakes and elevation was on the positive side for Swat, Gilgit, Shigar, and Shingo basins-a situation that may be attributed to the variable altitudinal pattern of temperature and precipitation. In order to explore such diverse patterns of lake behavior and relationship with influential factors in the HKH, detailed studies based on using high resolution image data coupled with in situ information are a prerequisite. Although an increase in lake area observed below 3500 m would be favorable for water resource management, but could be alarming in context of glacial flood hazards that need to be monitored critically on a long-term basis.

  13. A Dynamic Range Enhanced Readout Technique with a Two-Step TDC for High Speed Linear CMOS Image Sensors

    Directory of Open Access Journals (Sweden)

    Zhiyuan Gao

    2015-11-01

    Full Text Available This paper presents a dynamic range (DR enhanced readout technique with a two-step time-to-digital converter (TDC for high speed linear CMOS image sensors. A multi-capacitor and self-regulated capacitive trans-impedance amplifier (CTIA structure is employed to extend the dynamic range. The gain of the CTIA is auto adjusted by switching different capacitors to the integration node asynchronously according to the output voltage. A column-parallel ADC based on a two-step TDC is utilized to improve the conversion rate. The conversion is divided into coarse phase and fine phase. An error calibration scheme is also proposed to correct quantization errors caused by propagation delay skew within −Tclk~+Tclk. A linear CMOS image sensor pixel array is designed in the 0.13 μm CMOS process to verify this DR-enhanced high speed readout technique. The post simulation results indicate that the dynamic range of readout circuit is 99.02 dB and the ADC achieves 60.22 dB SNDR and 9.71 bit ENOB at a conversion rate of 2 MS/s after calibration, with 14.04 dB and 2.4 bit improvement, compared with SNDR and ENOB of that without calibration.

  14. Dynamic optimization of the complex adaptive controlling by the structure of enterprise’s product range

    Directory of Open Access Journals (Sweden)

    Andrey Fyodorovich Shorikov

    2013-06-01

    Full Text Available This paper reviews a methodical approach to solve multi-step dynamic problem of optimal integrated adaptive management of a product portfolio structure of the enterprise. For the organization of optimal adaptive terminal control of the system the recurrent algorithm, which reduces an initial multistage problem to the realization of the final sequence of problems of optimal program terminal control is offered. In turn, the decision of each problem of optimal program terminal control is reduced to the realization of the final sequence only single-step operations in the form of the problems solving of linear and convex mathematical programming. Thus, the offered approach allows to develop management solutions at current information support, which consider feedback, and which create the optimal structure of an enterprise’s product lines, contributing to optimising of profits, as well as maintenance of the desired level of profit for a long period of time

  15. Short-range dynamics and prediction of mesoscale flow patterns in the MISTRAL field experiment

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R.O.; Kaufmann, P.; Talkner, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    In a limited area of about 50 km by 50 km with complex topography, wind measurements on a dense network were performed during the MISTRAL field experiment in 1991-1992. From these data the characteristic wind fields were identified by an automated classification method. The dynamics of the resulting twelve typical regional flow patterns is studied. It is discussed how transitions between the flow patterns take place and how well the transition probabilities can be described in the framework of a Markov model. Guided by this discussion, a variety of prediction models were tested which allow a short-term forecast of the flow pattern type. It is found that a prediction model which uses forecast information from the synoptic scale has the best forecast skill. (author) 2 figs., 7 refs.

  16. Close-packed structure dynamics with finite-range interaction: computational mechanics with individual layer interaction.

    Science.gov (United States)

    Rodriguez-Horta, Edwin; Estevez-Rams, Ernesto; Lora-Serrano, Raimundo; Neder, Reinhard

    2017-09-01

    This is the second contribution in a series of papers dealing with dynamical models in equilibrium theories of polytypism. A Hamiltonian introduced by Ahmad & Khan [Phys. Status Solidi B (2000), 218, 425-430] avoids the unphysical assignment of interaction terms to fictitious entities given by spins in the Hägg coding of the stacking arrangement. In this paper an analysis of polytype generation and disorder in close-packed structures is made for such a Hamiltonian. Results are compared with a previous analysis using the Ising model. Computational mechanics is the framework under which the analysis is performed. The competing effects of disorder and structure, as given by entropy density and excess entropy, respectively, are discussed. It is argued that the Ahmad & Khan model is simpler and predicts a larger set of polytypes than previous treatments.

  17. Self-Biased Differential Rectifier with Enhanced Dynamic Range for Wireless Powering

    KAUST Repository

    Ouda, Mahmoud H.

    2016-08-29

    A self-biased, cross-coupled, differential rectifier is proposed with enhanced power-conversion efficiency over an extended range of input power. A prototype is designed for UHF 433MHz RF power-harvesting applications and is implemented using 0.18μm CMOS technology. The proposed rectifier architecture is compared to the conventional cross-coupled rectifier. It demonstrates an improvement of more than 40% in the rectifier power conversion efficiency (PCE) and an input power range extension of more than 50% relative to the conventional crosscoupled rectifier. A sensitivity of -15.2dBm (30μW) input power for 1V output voltage and a peak power-conversion efficiency of 65% are achieved for a 50kω load. © 2004-2012 IEEE.

  18. Motion of condensates in non-Markovian zero-range dynamics

    Science.gov (United States)

    Hirschberg, Ori; Mukamel, David; Schütz, Gunter M.

    2012-08-01

    The condensation transition in a non-Markovian zero-range process is studied in one and higher dimensions. In the mean-field approximation, corresponding to infinite-range hopping, the model exhibits condensation with a stationary condensate, as in the Markovian case, but with a modified phase diagram. In the case of nearest-neighbor hopping, the condensate is found to drift by means of a ‘slinky’ motion from one site to the next. The mechanism of the drift is explored numerically in detail. A modified model with nearest-neighbor hopping which allows exact calculation of the steady state is introduced. The steady state of this model is found to be a product measure, and the condensate is stationary.

  19. Motion of condensates in non-Markovian zero-range dynamics

    International Nuclear Information System (INIS)

    Hirschberg, Ori; Mukamel, David; Schütz, Gunter M

    2012-01-01

    The condensation transition in a non-Markovian zero-range process is studied in one and higher dimensions. In the mean-field approximation, corresponding to infinite-range hopping, the model exhibits condensation with a stationary condensate, as in the Markovian case, but with a modified phase diagram. In the case of nearest-neighbor hopping, the condensate is found to drift by means of a ‘slinky’ motion from one site to the next. The mechanism of the drift is explored numerically in detail. A modified model with nearest-neighbor hopping which allows exact calculation of the steady state is introduced. The steady state of this model is found to be a product measure, and the condensate is stationary. (paper)

  20. Attractive short-range interatomic potential in the lattice dynamics of niobium and tantalum

    International Nuclear Information System (INIS)

    Onwuagba, B.N.; Pal, S.

    1987-01-01

    It is shown in the framework of the pseudopotential approach that there is a sizable attractive short-range component of the interatomic potential due to the s-d interaction which has the same functional form in real space as the Born-Mayer repulsion due to the overlap of core electron wave functions centred on neighbouring ions. The magnitude of this attractive component is such as to completely cancel the conventional Born-Mayer repulsion, making the resultant short-range interatomic potential attractive rather than repulsive. Numerical calculations show that the attractive interatomics potential, which represents the local-field correction, leads to a better understanding of the occurrence of the soft modes in the phonon dispersion curves of niobium and tantalum

  1. Dynamical effects and time scale in fission processes in nuclear collisions in the fermi energy range

    International Nuclear Information System (INIS)

    Colin, J.; Bocage, F.; Louvel, M.; Bellaize, N.; Bougault, R.; Brou, R.; Cussol, D.; Durand, D.; Genouin-Duhamel, E.; Lecolley, J.F.; Le Neindre, N.; Lopez, O.; Nguyen, A.D.; Peter, J.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Brun, C. le; Genoux-Lubain, A.

    1999-01-01

    Recent experimental results concerning heavy systems (Pb+Au, Pb+Ag, Pb+Al, Gd+U, Gd+C, Ta+Au, U+U, U+C, Xe+Sn... o btained at Ganil by the Indra and Nautilus collaborations will be presented. A study of reaction mechanisms has shown the dominant binary and highly dissipative character of the process. The two heavy and excited fragments produced after the first stage of the interaction can experience various decay modes: evaporation, fission, multifragmentation. However, deviations from this simple picture have been found by analysing angular and velocity distributions of light charge particles, IMF's (Intermediate Mass Fragment) and fragments. Indeed, there is an amount of matter in excess emitted in-between the two primary sources suggesting either the existence of a mid-rapidity source similar to the one observed in the relativistic regime (participants) or a strong deformation induced by the dynamics of the collision (neck instability). This last scenario is explored by analysing in details the angular distributions of the fission fragments. More precisely, authors observed two components: The first one is isotropic and consistent with the predictions of a statistical model, the second is aligned along the velocity direction of the fissioning nuclei and has to be compared with the predictions of dynamical calculations. In this talk, authors present the probability associated to each component as a function of the system size, the charge asymmetry of the fission fragments, the incident energy and the impact parameter. From the statistical component authors extract the temperature, the charge and the angular momentum of the fissioning nuclei. From the second component authors propose a scenario to explain such process and authors discuss the physical parameters which can be extracted

  2. Dynamical effects and time scale in fission processes in nuclear collisions in the Fermi energy range

    International Nuclear Information System (INIS)

    Colin, J.; Bocage, F.; Louvel, M.

    1999-10-01

    Recent experimental results concerning heavy systems (Pb+Au, Pb+Ag, Pb+Al, Gd+U, Gd+C, Ta+Au, U+U, U+C, Xe+Sn...) obtained at Ganil by the Indra and Nautilus collaborations will be presented. A study of reaction mechanisms has shown the dominant binary and highly dissipative character of the process. The two heavy and excited fragments produced after the first stage of the interaction can experience various decay modes: evaporation, fission, multifragmentation. However, deviations from this simple picture have been found by analysing angular and velocity distribution of light charge particles, IMF's (Intermediate Mass Fragment) and fragments. Indeed, there is an amount of matter in excess emitted in-between the two primary sources suggesting either the existence of a mi-rapidity source similar to the one observed in the relativistic regime (participants) or a strong deformation induced by the dynamics of the collision (neck instability). This last scenario is explored by analysing in details the angular distributions of the fission fragments. More precisely, we observed two components: the first one is isotropic and consistent with the predictions of a statistical model, the second is aligned along the velocity direction of the fissioning nuclei and has to be compared with the predictions of dynamical calculations. In this talk, we present the probability associated to each component as a function of the system size, the charge asymmetry of the fission fragments, the incident energy and the impact parameter. From the statistical component we extract the temperature, the charge and the angular momentum of the fissioning nuclei. From the second component we propose a scenario to explain such process and we discuss the physical parameters which can be extracted. (authors)

  3. Former Spencer Artillery Range, Tennessee Classification Demonstration Open Field and Dynamic Areas

    Science.gov (United States)

    2016-01-01

    capabilities of the production community by enhancing and streamlining UX -Analyze’s workflow and functionality; by offering training documents...Inc. UXA UX -Analyze List of Figures Figure 3-1: Spencer Range Open Area Metal Mapper ROC Curve ............................................... 5...easting and horizontal is less than 0.1 meter. Statistics calculations are part of the Geosoft UX -Analyze (UXA) process module for IVS and include, in

  4. Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems.

    Science.gov (United States)

    Gole, Vaibhav C; Woodhouse, Rebecca; Caraguel, Charles; Moyle, Talia; Rault, Jean-Loup; Sexton, Margaret; Chousalkar, Kapil

    2017-03-01

    The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variable-number tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates ( n = 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA , ironA , and misL There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters. IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella serovars in

  5. Development and testing of a fast Fourier transform high dynamic-range spectral diagnostics for millimeter wave characterization

    International Nuclear Information System (INIS)

    Thoen, D. J.; Bongers, W. A.; Westerhof, E.; Baar, M. R. de; Berg, M. A. van den; Beveren, V. van; Goede, A. P. H.; Graswinckel, M. F.; Schueller, F. C.; Oosterbeek, J. W.; Buerger, A.; Hennen, B. A.

    2009-01-01

    A fast Fourier transform (FFT) based wide range millimeter wave diagnostics for spectral characterization of scattered millimeter waves in plasmas has been successfully brought into operation. The scattered millimeter waves are heterodyne downconverted and directly digitized using a fast analog-digital converter and a compact peripheral component interconnect computer. Frequency spectra are obtained by FFT in the time domain of the intermediate frequency signal. The scattered millimeter waves are generated during high power electron cyclotron resonance heating experiments on the TEXTOR tokamak and demonstrate the performance of the diagnostics and, in particular, the usability of direct digitizing and Fourier transformation of millimeter wave signals. The diagnostics is able to acquire 4 GHz wide spectra of signals in the range of 136-140 GHz. The rate of spectra is tunable and has been tested between 200 000 spectra/s with a frequency resolution of 100 MHz and 120 spectra/s with a frequency resolution of 25 kHz. The respective dynamic ranges are 52 and 88 dB. Major benefits of the new diagnostics are a tunable time and frequency resolution due to postdetection, near-real time processing of the acquired data. This diagnostics has a wider application in astrophysics, earth observation, plasma physics, and molecular spectroscopy for the detection and analysis of millimeter wave radiation, providing high-resolution spectra at high temporal resolution and large dynamic range.

  6. Piezo-based, high dynamic range, wide bandwidth steering system for optical applications

    Science.gov (United States)

    Karasikov, Nir; Peled, Gal; Yasinov, Roman; Feinstein, Alan

    2017-05-01

    Piezoelectric motors and actuators are characterized by direct drive, fast response, high positioning resolution and high mechanical power density. These properties are beneficial for optical devices such as gimbals, optical image stabilizers and mirror angular positioners. The range of applications includes sensor pointing systems, image stabilization, laser steering and more. This paper reports on the construction, properties and operation of three types of piezo based building blocks for optical steering applications: a small gimbal and a two-axis OIS (Optical Image Stabilization) mechanism, both based on piezoelectric motors, and a flexure-assisted piezoelectric actuator for mirror angular positioning. The gimbal weighs less than 190 grams, has a wide angular span (solid angle of > 2π) and allows for a 80 micro-radian stabilization with a stabilization frequency up to 25 Hz. The OIS is an X-Y, closed loop, platform having a lateral positioning resolution better than 1 μm, a stabilization frequency up to 25 Hz and a travel of +/-2 mm. It is used for laser steering or positioning of the image sensor, based on signals from a MEMS Gyro sensor. The actuator mirror positioner is based on three piezoelectric actuation axes for tip tilt (each providing a 50 μm motion range), has a positioning resolution of 10 nm and is capable of a 1000 Hz response. A combination of the gimbal with the mirror positioner or the OIS stage is explored by simulations, indicating a <10 micro-radian stabilization capability under substantial perturbation. Simulations and experimental results are presented for a combined device facilitating both wide steering angle range and bandwidth.

  7. Dynamics and genetic structure of Argentine ant supercolonies in their native range

    DEFF Research Database (Denmark)

    Vogel, Valérie; Pedersen, Jes S; d'Ettorre, Patrizia

    2009-01-01

    analyses revealed the presence of 11 supercolonies (width 1 to 515 m) over a 3-km transect. As in the introduced range, there was always strong aggression between but never within supercolonies. The genetic data were in perfect agreement with the behavioral tests, all nests being assigned to identical...... supercolonies with the different methods. There was strong genetic differentiation between supercolonies but no genetic differentiation among nests within supercolonies. We never found more than a single mitochondrial haplotype per supercolony, further supporting the view that supercolonies are closed breeding...

  8. Nonlinear compensation to enhance the input dynamic range in analog optical fiber links for the high current short circuit test

    International Nuclear Information System (INIS)

    Rodriguez, Joaquin; Garduno, Raul; Velazquez, Jose; Montero, Julio

    2010-01-01

    Due to their galvanic insulation and EMI immunity properties, optical fiber links have been used in the transmitter–receiver system of an analog voltage measuring system at a high-power mid-voltage testing laboratory with a highly aggressive EMI environment. This paper introduces the application of a nonlinear compensation to limit the voltage range at the input of a voltage-controlled oscillator, which is used to produce the pulsed frequency modulation needed to transmit the analog signals over the optical fiber links. The proposed dynamic range compensation system is based on nonlinear circuits to accommodate the input range of the voltage-controlled oscillator. This approach increases the transient signal handling capabilities of the measuring system. This work demonstrates that the nonlinear compensated optical fiber approach yields a unique, electrically isolated, lightning-proof analog data transmission system, for remote measuring systems in the highly aggressive EMI environment of high-power test laboratories

  9. Application of a New Dynamic Heating System Model Using a Range of Common Control Strategies

    Directory of Open Access Journals (Sweden)

    Joshua Fong

    2016-06-01

    Full Text Available This research investigates the overall heating energy consumptions using various control strategies, secondary heat emitters, and primary plant for a building. Previous research has successfully demonstrated that a dynamic distributed heat emitter model embedded within a simplified third-order lumped parameter building model is capable of achieving improved results when compared to other commercially available modelling tools. With the enhanced ability to capture transient effects of emitter thermal capacity, this research studies the influence of control strategies and primary plant configurations on the rate of energy consumption of a heating system. Four alternative control strategies are investigated: zone feedback; weather-compensated; a combination of both of these methods; and thermostatic control. The plant alternative configurations consist of conventional boilers, biomass boilers, and heat pumps supporting radiator heating and underfloor heating. The performance of the model is tested on a primary school building and can be applied to any residential or commercial building with a heating system. Results show that the new methods reported offer greater detail and rigor in the conduct of building energy modelling.

  10. Black holes as random particles: entanglement dynamics in infinite range and matrix models

    International Nuclear Information System (INIS)

    Magán, Javier M.

    2016-01-01

    We first propose and study a quantum toy model of black hole dynamics. The model is unitary, displays quantum thermalization, and the Hamiltonian couples every oscillator with every other, a feature intended to emulate the color sector physics of large-N matrix models. Considering out of equilibrium initial states, we analytically compute the time evolution of every correlator of the theory and of the entanglement entropies, allowing a proper discussion of global thermalization/scrambling of information through the entire system. Microscopic non-locality causes factorization of reduced density matrices, and entanglement just depends on the time evolution of occupation densities. In the second part of the article, we show how the gained intuition extends to large-N matrix models, where we provide a gauge invariant entanglement entropy for ‘generalized free fields’, again depending solely on the quasinormal frequencies. The results challenge the fast scrambling conjecture and point to a natural scenario for the emergence of the so-called brick wall or stretched horizon. Finally, peculiarities of these models in regards to the thermodynamic limit and the information paradox are highlighted.

  11. A Methodology Of Map-Guided Autonomous Navigation With Range Sensor In Dynamic Environment

    Science.gov (United States)

    Meng, Alex C.; Wand, Marty; Hwang, Vincent S.

    1989-03-01

    This paper describes the work for a map-guided robot (AGV) maneuvering in dynamic factory floor environment. The robot is equipped with a narrow-beam sonar to detect obstacles. In factory applications, the location and orientation of the robot will be determined by external sensors. A path from start to target location will be digitized into a sequence of waypoints and the robot navigates locally by dead-reckoning between two adjacent waypoints. Autonomous navigation, in this setup, is viewed in terms of three components: automatic path plannihg for the given floor layout, the start and target locations of the robot, automatic path replanning after detecting obstacles, and local navigation which should always lead the robot out of a trap (cul-de-sac) if one occurs. For any given floor layout, we model the passage ways between obstacles (processing machines) as a connected graph knowns as the Voronoi graph. From the robot's point of view, the graph is the map to plan paths and navigate. Path planning is based on the retraction method. After detecting an obstacle, path replanning will be invoked. Algorithms for path planning, path replanning, and local navigation are given.

  12. Seasonality in cholera dynamics: A rainfall-driven model explains the wide range of patterns in endemic areas

    Science.gov (United States)

    Baracchini, Theo; King, Aaron A.; Bouma, Menno J.; Rodó, Xavier; Bertuzzo, Enrico; Pascual, Mercedes

    2017-10-01

    Seasonal patterns in cholera dynamics exhibit pronounced variability across geographical regions, showing single or multiple peaks at different times of the year. Although multiple hypotheses related to local climate variables have been proposed, an understanding of this seasonal variation remains incomplete. The historical Bengal region, which encompasses the full range of cholera's seasonality observed worldwide, provides a unique opportunity to gain insights on underlying environmental drivers. Here, we propose a mechanistic, rainfall-temperature driven, stochastic epidemiological model which explicitly accounts for the fluctuations of the aquatic reservoir, and analyze with this model the historical dataset of cholera mortality in the Bengal region. Parameters are inferred with a recently developed sequential Monte Carlo method for likelihood maximization in partially observed Markov processes. Results indicate that the hydrological regime is a major driver of the seasonal dynamics of cholera. Rainfall tends to buffer the propagation of the disease in wet regions due to the longer residence times of water in the environment and an associated dilution effect, whereas it enhances cholera resurgence in dry regions. Moreover, the dynamics of the environmental water reservoir determine whether the seasonality is unimodal or bimodal, as well as its phase relative to the monsoon. Thus, the full range of seasonal patterns can be explained based solely on the local variation of rainfall and temperature. Given the close connection between cholera seasonality and environmental conditions, a deeper understanding of the underlying mechanisms would allow the better management and planning of public health policies with respect to climate variability and climate change.

  13. Climatic niche conservatism and the evolutionary dynamics in species range boundaries

    DEFF Research Database (Denmark)

    Olalla-Tárraga1, Miguel Á.; McInnes, Linsey; Bini, Luis M.

    2011-01-01

    and amphibians. We characterized the climatic niche of each species by using a suite of variables and separately investigate conservatism in each variable using both taxonomic and phylogenetic approaches. Finally, we explored the spatial, taxonomic and phylogenetic patterns in recent climatic niche evolution......Aim Comparative evidence for phylogenetic niche conservatism – the tendency for lineages to retain their ancestral niches over long time scales – has so far been mixed, depending on spatial and taxonomic scale. We quantify and compare conservatism in the climatic factors defining range boundaries...... in extant continental mammals and amphibians in order to identify those factors that are most evolutionarily conserved, and thus hypothesized to have played a major role in determining the geographic distributions of many species. We also test whether amphibians show stronger signals of climatic niche...

  14. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Sjue, S. K. L., E-mail: sjue@lanl.gov; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A. [Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-01-15

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.

  15. Dynamical Quantum Phase Transitions in Spin Chains with Long-Range Interactions: Merging Different Concepts of Nonequilibrium Criticality

    Science.gov (United States)

    Žunkovič, Bojan; Heyl, Markus; Knap, Michael; Silva, Alessandro

    2018-03-01

    We theoretically study the dynamics of a transverse-field Ising chain with power-law decaying interactions characterized by an exponent α , which can be experimentally realized in ion traps. We focus on two classes of emergent dynamical critical phenomena following a quantum quench from a ferromagnetic initial state: The first one manifests in the time-averaged order parameter, which vanishes at a critical transverse field. We argue that such a transition occurs only for long-range interactions α ≤2 . The second class corresponds to the emergence of time-periodic singularities in the return probability to the ground-state manifold which is obtained for all values of α and agrees with the order parameter transition for α ≤2 . We characterize how the two classes of nonequilibrium criticality correspond to each other and give a physical interpretation based on the symmetry of the time-evolved quantum states.

  16. A Very Low Dark Current Temperature-Resistant, Wide Dynamic Range, Complementary Metal Oxide Semiconductor Image Sensor

    Science.gov (United States)

    Mizobuchi, Koichi; Adachi, Satoru; Tejada, Jose; Oshikubo, Hiromichi; Akahane, Nana; Sugawa, Shigetoshi

    2008-07-01

    A very low dark current (VLDC) temperature-resistant approach which best suits a wide dynamic range (WDR) complementary metal oxide semiconductor (CMOS) image sensor with a lateral over-flow integration capacitor (LOFIC) has been developed. By implementing a low electric field photodiode without a trade-off of full well-capacity, reduced plasma damage, re-crystallization, and termination of silicon-silicon dioxide interface states in the front end of line and back end of line (FEOL and BEOL) in a 0.18 µm, two polycrystalline silicon, three metal (2P3M) process, the dark current is reduced to 11 e-/s/pixel (0.35 e-/s/µm2: pixel area normalized) at 60 °C, which is the lowest value ever reported. For further robustness at low and high temperatures, 1/3-in., 5.6-µm pitch, 800×600 pixel sensor chips with low noise readout circuits designed for a signal and noise hold circuit and a programmable gain amplifier (PGA) have also been deposited with an inorganic cap layer on a micro-lens and covered with a metal hermetically sealed package assembly. Image sensing performance results in 2.4 e-rms temporal noise and 100 dB dynamic range (DR) with 237 ke- full well-capacity. The operating temperature range is extended from -40 to 85 °C while retaining good image quality.

  17. Intra- and interobserver reliability of gray scale/dynamic range evaluation of ultrasonography using a standardized phantom

    International Nuclear Information System (INIS)

    Lee, Song; Choi, Joon Il; Park, Michael Yong; Yeo, Dong Myung; Byun, Jae Young; Jung, Seung Eun; Rha, Sung Eun; Oh, Soon Nam; Lee, Young Joon

    2014-01-01

    To evaluate intra- and interobserver reliability of the gray scale/dynamic range of the phantom image evaluation of ultrasonography using a standardized phantom, and to assess the effect of interactive education on the reliability. Three radiologists (a resident, and two board-certified radiologists with 2 and 7 years of experience in evaluating ultrasound phantom images) performed the gray scale/dynamic range test for an ultrasound machine using a standardized phantom. They scored the number of visible cylindrical structures of varying degrees of brightness and made a pass or fail decision. First, they scored 49 phantom images twice from a 2010 survey with limited knowledge of phantom images. After this, the radiologists underwent two hours of interactive education for the phantom images and scored another 91 phantom images from a 2011 survey twice. Intra- and interobserver reliability before and after the interactive education session were analyzed using K analyses. Before education, the K-value for intraobserver reliability for the radiologist with 7 years of experience, 2 years of experience, and the resident was 0.386, 0.469, and 0.465, respectively. After education, the K-values were improved (0.823, 0.611, and 0.711, respectively). For interobserver reliability, the K-value was also better after the education for the 3 participants (0.067, 0.002, and 0.547 before education; 0.635, 0.667, and 0.616 after education, respectively). The intra- and interobserver reliability of the gray scale/dynamic range was fair to substantial. Interactive education can improve reliability. For more reliable results, double- checking of phantom images by multiple reviewers is recommended.

  18. Platinum Nanocatalyst Amplification: Redefining the Gold Standard for Lateral Flow Immunoassays with Ultrabroad Dynamic Range.

    Science.gov (United States)

    Loynachan, Colleen N; Thomas, Michael R; Gray, Eleanor R; Richards, Daniel A; Kim, Jeongyun; Miller, Benjamin S; Brookes, Jennifer C; Agarwal, Shweta; Chudasama, Vijay; McKendry, Rachel A; Stevens, Molly M

    2018-01-23

    Paper-based lateral flow immunoassays (LFIAs) are one of the most widely used point-of-care (PoC) devices; however, their application in early disease diagnostics is often limited due to insufficient sensitivity for the requisite sample sizes and the short time frames of PoC testing. To address this, we developed a serum-stable, nanoparticle catalyst-labeled LFIA with a sensitivity surpassing that of both current commercial and published sensitivities for paper-based detection of p24, one of the earliest and most conserved biomarkers of HIV. We report the synthesis and characterization of porous platinum core-shell nanocatalysts (PtNCs), which show high catalytic activity when exposed to complex human blood serum samples. We explored the application of antibody-functionalized PtNCs with strategically and orthogonally modified nanobodies with high affinity and specificity toward p24 and established the key larger nanoparticle size regimes needed for efficient amplification and performance in LFIA. Harnessing the catalytic amplification of PtNCs enabled naked-eye detection of p24 spiked into sera in the low femtomolar range (ca. 0.8 pg·mL -1 ) and the detection of acute-phase HIV in clinical human plasma samples in under 20 min. This provides a versatile absorbance-based and rapid LFIA with sensitivity capable of significantly reducing the HIV acute phase detection window. This diagnostic may be readily adapted for detection of other biomolecules as an ultrasensitive screening tool for infectious and noncommunicable diseases and can be capitalized upon in PoC settings for early disease detection.

  19. A Dynamic Range Expansion Technique for CMOS Image Sensors with Dual Charge Storage in a Pixel and Multiple Sampling

    OpenAIRE

    Shafie, Suhaidi; Kawahito, Shoji; Itoh, Shinya

    2008-01-01

    A dynamic range expansion technique for CMOS image sensors with dual charge storage in a pixel and multiple sampling technique is presented. Each pixel contains a photodiode and a storage diode which is connected to the photodiode via a separation gate. The sensitivity of the signal charge in the storage diode can be controlled either by a separation gate which limits the charge to flow into the storage diode or by controlling the accumulation time in the storage diode. The operation of the s...

  20. Improving the off-axis spatial resolution and dynamic range of the NIF X-ray streak cameras (invited).

    Science.gov (United States)

    MacPhee, A G; Dymoke-Bradshaw, A K L; Hares, J D; Hassett, J; Hatch, B W; Meadowcroft, A L; Bell, P M; Bradley, D K; Datte, P S; Landen, O L; Palmer, N E; Piston, K W; Rekow, V V; Hilsabeck, T J; Kilkenny, J D

    2016-11-01

    We report simulations and experiments that demonstrate an increase in spatial resolution of the NIF core diagnostic x-ray streak cameras by at least a factor of two, especially off axis. A design was achieved by using a corrector electron optic to flatten the field curvature at the detector plane and corroborated by measurement. In addition, particle in cell simulations were performed to identify the regions in the streak camera that contribute the most to space charge blurring. These simulations provide a tool for convolving synthetic pre-shot spectra with the instrument function so signal levels can be set to maximize dynamic range for the relevant part of the streak record.

  1. Tissue oximetry: a comparison of mean values of regional tissue saturation, reproducibility and dynamic range of four NIRS-instruments on the human forearm

    DEFF Research Database (Denmark)

    Hyttel-Sørensen, Simon; Sorensen, Line C; Riera, Joan

    2011-01-01

    We compared absolute values of regional tissue hemoglobin saturation (StO(2)), reproducibility, and dynamic range of four different instruments on the forearm of adults. The sensors were repositioned 10 times on each subject. Dynamic range was estimated by exercise with subsequent arterial occlus...

  2. Characterization of a wide dynamic-range, radiation-tolerant charge-digitizer asic for monitoring of Beam losses

    CERN Document Server

    Guido Venturini, G G; Dehning, B; Kayal, M

    2012-01-01

    An Application Specific Integrated Circuit (ASIC) has been designed and fabricated to provide a compact solution to digitize current signals from ionization chambers and diamond detectors, employed as beam loss monitors at CERN and several other high energy physics facilities. The circuit topology has been devised to accept positive and negative currents, to have a wide dynamic range (above 120 dB), withstand radiation levels over 10 Mrad and offer different modes of operation, covering a broad range of applications. Furthermore, an internal conversion reference is employed in the digitization, to provide an accurate absolute measurement. This paper discusses the detailed characterization of the first prototype: linearity, radiation tolerance and temperature dependence of the conversion, as well as implications and system-level considerations regarding its use for beam instrumentation applications in a high energy physics facility.

  3. Design Issues for Low Power Integrated Thermal Flow Sensors with Ultra-Wide Dynamic Range and Low Insertion Loss

    Directory of Open Access Journals (Sweden)

    Paolo Bruschi

    2012-04-01

    Full Text Available Flow sensors are the key elements in most systems for monitoring and controlling fluid flows. With the introduction of MEMS thermal flow sensors, unprecedented performances, such as ultra wide measurement ranges, low power consumptions and extreme miniaturization, have been achieved, although several critical issues have still to be solved. In this work, a systematic approach to the design of integrated thermal flow sensors, with specification of resolution, dynamic range, power consumption and pressure insertion loss is proposed. All the critical components of the sensors, namely thermal microstructure, package and read-out interface are examined, showing their impact on the sensor performance and indicating effective optimization strategies. The proposed design procedures are supported by experiments performed using a recently developed test chip,including several different sensing structures and a flexible electronic interface.

  4. Static, dynamic and electronic properties of expanded fluid mercury in the metal-nonmetal transition range. An ab initio study

    Energy Technology Data Exchange (ETDEWEB)

    CalderIn, L [Research Computing and Cyberinfrastructure, The Pennsylvania State University, University Park, PA 16802 (United States); Gonzalez, L E; Gonzalez, D J, E-mail: david@liq1.fam.cie.uva.es [Departamento de Fisica Teorica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid (Spain)

    2011-09-21

    Fluid Hg undergoes a metal-nonmetal (M-NM) transition when expanded toward a density of around 9 g cm{sup -3}. We have performed ab initio molecular dynamics simulations for several thermodynamic states around the M-NM transition range and the associated static, dynamic and electronic properties have been analyzed. The calculated static structure shows a good agreement with the available experimental data. It is found that the volume expansion decreases the number of nearest neighbors from 10 (near the triple point) to around 8 at the M-NM transition region. Moreover, these neighbors are arranged into two subshells and the decrease in the number of neighbors occurs in the inner subshell. The calculated dynamic structure factors agree fairly well with their experimental counterparts obtained by inelastic x-ray scattering experiments, which display inelastic side peaks. The derived dispersion relation exhibits some positive dispersion for all the states, although its value around the M-NM transition region is not as marked as suggested by the experiment. We have also calculated the electronic density of states, which shows the appearance of a gap at a density of around 8.3 g cm{sup -3}. (paper)

  5. Subzero temperature chromatography for reduced back-exchange and improved dynamic range in amide hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Venable, John D; Okach, Linda; Agarwalla, Sanjay; Brock, Ansgar

    2012-11-06

    Amide hydrogen/deuterium exchange is a commonly used technique for studying the dynamics of proteins and their interactions with other proteins or ligands. When coupled with liquid chromatography and mass spectrometry, hydrogen/deuterium exchange provides several unique advantages over other structural characterization techniques including very high sensitivity, the ability to analyze proteins in complex environments, and a large mass range. A fundamental limitation of the technique arises from the loss of the deuterium label (back-exchange) during the course of the analysis. A method to limit loss of the label during the separation stage of the analysis using subzero temperature reversed-phase chromatography is presented. The approach is facilitated by the use of buffer modifiers that prevent freezing. We evaluated ethylene glycol, dimethyl formamide, formamide, and methanol for their freezing point suppression capabilities, effects on peptide retention, and their compatibilities with electrospray ionization. Ethylene glycol was used extensively because of its good electrospray ionization compatibility; however, formamide has potential to be a superior modifier if detrimental effects on ionization can be overcome. It is demonstrated using suitable buffer modifiers that separations can be performed at temperatures as low as -30 °C with negligible loss of the deuterium label, even during long chromatographic separations. The reduction in back-exchange is shown to increase the dynamic range of hydrogen/deuterium exchange mass spectrometry in terms of mixture complexity and the magnitude with which changes in deuteration level can be quantified.

  6. Fast, Highly-Sensitive, and Wide-Dynamic-Range Interdigitated Capacitor Glucose Biosensor Using Solvatochromic Dye-Containing Sensing Membrane.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Khalilian, Alireza; Kang, Shin-Won

    2016-02-20

    In this paper, we proposed an interdigitated capacitor (IDC)-based glucose biosensor to measure different concentrations of glucose from 1 μM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt's dye (R-dye). These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC)] and N,N-Dimethylacetamide (DMAC) solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE) by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance.

  7. ISSLS PRIZE IN BIOENGINEERING SCIENCE 2018: dynamic imaging of degenerative spondylolisthesis reveals mid-range dynamic lumbar instability not evident on static clinical radiographs.

    Science.gov (United States)

    Dombrowski, Malcolm E; Rynearson, Bryan; LeVasseur, Clarissa; Adgate, Zach; Donaldson, William F; Lee, Joon Y; Aiyangar, Ameet; Anderst, William J

    2018-04-01

    Degenerative spondylolisthesis (DS) in the setting of symptomatic lumbar spinal stenosis is commonly treated with spinal fusion in addition to decompression with laminectomy. However, recent studies have shown similar clinical outcomes after decompression alone, suggesting that a subset of DS patients may not require spinal fusion. Identification of dynamic instability could prove useful for predicting which patients are at higher risk of post-laminectomy destabilization necessitating fusion. The goal of this study was to determine if static clinical radiographs adequately characterize dynamic instability in patients with lumbar degenerative spondylolisthesis (DS) and to compare the rotational and translational kinematics in vivo during continuous dynamic flexion activity in DS versus asymptomatic age-matched controls. Seven patients with symptomatic single level lumbar DS (6 M, 1 F; 66 ± 5.0 years) and seven age-matched asymptomatic controls (5 M, 2 F age 63.9 ± 6.4 years) underwent biplane radiographic imaging during continuous torso flexion. A volumetric model-based tracking system was used to track each vertebra in the radiographic images using subject-specific 3D bone models from high-resolution computed tomography (CT). In vivo continuous dynamic sagittal rotation (flexion/extension) and AP translation (slip) were calculated and compared to clinical measures of intervertebral flexion/extension and AP translation obtained from standard lateral flexion/extension radiographs. Static clinical radiographs underestimate the degree of AP translation seen on dynamic in vivo imaging (1.0 vs 3.1 mm; p = 0.03). DS patients demonstrated three primary motion patterns compared to a single kinematic pattern in asymptomatic controls when analyzing continuous dynamic in vivo imaging. 3/7 (42%) of patients with DS demonstrated aberrant mid-range motion. Continuous in vivo dynamic imaging in DS reveals a spectrum of aberrant motion with significantly greater

  8. Sexual segregation in juvenile New Zealand sea lion foraging ranges: implications for intraspecific competition, population dynamics and conservation.

    Science.gov (United States)

    Leung, Elaine S; Chilvers, B Louise; Nakagawa, Shinichi; Moore, Antoni B; Robertson, Bruce C

    2012-01-01

    Sexual segregation (sex differences in spatial organisation and resource use) is observed in a large range of taxa. Investigating causes for sexual segregation is vital for understanding population dynamics and has important conservation implications, as sex differences in foraging ecology may affect vulnerability to area-specific human activities. Although behavioural ecologists have proposed numerous hypotheses for this phenomenon, the underlying causes of sexual segregation are poorly understood. We examined the size-dimorphism and niche divergence hypotheses as potential explanations for sexual segregation in the New Zealand (NZ) sea lion (Phocarctos hookeri), a nationally critical, declining species impacted by trawl fisheries. We used satellite telemetry and linear mixed effects models to investigate sex differences in the foraging ranges of juvenile NZ sea lions. Male trip distances and durations were almost twice as long as female trips, with males foraging over the Auckland Island shelf and in further locations than females. Sex was the most important variable in trip distance, maximum distance travelled from study site, foraging cycle duration and percent time at sea whereas mass and age had small effects on these characteristics. Our findings support the predictions of the niche divergence hypothesis, which suggests that sexual segregation acts to decrease intraspecific resource competition. As a consequence of sexual segregation in foraging ranges, female foraging grounds had proportionally double the overlap with fisheries operations than males. This distribution exposes female juvenile NZ sea lions to a greater risk of resource competition and bycatch from fisheries than males, which can result in higher female mortality. Such sex-biased mortality could impact population dynamics, because female population decline can lead to decreased population fecundity. Thus, effective conservation and management strategies must take into account sex differences

  9. Sexual segregation in juvenile New Zealand sea lion foraging ranges: implications for intraspecific competition, population dynamics and conservation.

    Directory of Open Access Journals (Sweden)

    Elaine S Leung

    Full Text Available Sexual segregation (sex differences in spatial organisation and resource use is observed in a large range of taxa. Investigating causes for sexual segregation is vital for understanding population dynamics and has important conservation implications, as sex differences in foraging ecology may affect vulnerability to area-specific human activities. Although behavioural ecologists have proposed numerous hypotheses for this phenomenon, the underlying causes of sexual segregation are poorly understood. We examined the size-dimorphism and niche divergence hypotheses as potential explanations for sexual segregation in the New Zealand (NZ sea lion (Phocarctos hookeri, a nationally critical, declining species impacted by trawl fisheries. We used satellite telemetry and linear mixed effects models to investigate sex differences in the foraging ranges of juvenile NZ sea lions. Male trip distances and durations were almost twice as long as female trips, with males foraging over the Auckland Island shelf and in further locations than females. Sex was the most important variable in trip distance, maximum distance travelled from study site, foraging cycle duration and percent time at sea whereas mass and age had small effects on these characteristics. Our findings support the predictions of the niche divergence hypothesis, which suggests that sexual segregation acts to decrease intraspecific resource competition. As a consequence of sexual segregation in foraging ranges, female foraging grounds had proportionally double the overlap with fisheries operations than males. This distribution exposes female juvenile NZ sea lions to a greater risk of resource competition and bycatch from fisheries than males, which can result in higher female mortality. Such sex-biased mortality could impact population dynamics, because female population decline can lead to decreased population fecundity. Thus, effective conservation and management strategies must take into account

  10. Detection and elimination of the electromagnetic interferences in the neutron flux measurement circuit, Source Range; Deteccion y eliminacion de interferencias electromagneticas en el circuito de medicion de flujo neutronico, rango de fuente

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, J. M.; Esguivillas, L.; Valle, J. L.

    2010-07-01

    This paper compiles an experience in Asco I Nuclear Power Plant about electromagnetic interferences associated to the neutron flux measurement system, Source Range Asco I NPP. The circuit affected is the proportional detector (BF3) located outside the reactor vessel to measure the neutron leakage in shutdown and in start-up.

  11. High Dynamic Range Video

    CERN Document Server

    Myszkowski, Karol

    2008-01-01

    This book presents a complete pipeline forHDR image and video processing fromacquisition, through compression and quality evaluation, to display. At the HDR image and video acquisition stage specialized HDR sensors or multi-exposure techniques suitable for traditional cameras are discussed. Then, we present a practical solution for pixel values calibration in terms of photometric or radiometric quantities, which are required in some technically oriented applications. Also, we cover the problem of efficient image and video compression and encoding either for storage or transmission purposes, in

  12. A novel opinion dynamics model based on expanded observation ranges and individuals’ social influences in social networks

    Science.gov (United States)

    Diao, Su-Meng; Liu, Yun; Zeng, Qing-An; Luo, Gui-Xun; Xiong, Fei

    2014-12-01

    In this paper, we propose an opinion dynamics model in order to investigate opinion evolution and interactions and the behavior of individuals. By introducing social influence and its feedback mechanism, the proposed model can highlight the heterogeneity of individuals and reproduce realistic online opinion interactions. It can also expand the observation range of affected individuals. Combining psychological studies on the social impact of majorities and minorities, affected individuals update their opinions by balancing social impact from both supporters and opponents. It can be seen that complete consensus is not always obtained. When the initial density of either side is greater than 0.8, the enormous imbalance leads to complete consensus. Otherwise, opinion clusters consisting of a set of tightly connected individuals who hold similar opinions appear. Moreover, a tradeoff is discovered between high interaction intensity and low stability with regard to observation ranges. The intensity of each interaction is negatively correlated with observation range, while the stability of each individual’s opinion positively affects the correlation. Furthermore, the proposed model presents the power-law properties in the distribution of individuals’ social influences, which is in agreement with people’s daily cognition. Additionally, it is proven that the initial distribution of individuals’ social influences has little effect on the evolution.

  13. Wide Dynamic Range Multiband Infrared Radiometer for In-Fire Measurements of Wildland Fire Radiant Flux Density

    Science.gov (United States)

    Kremens, R.; Dickinson, M. B.; Hardy, C.; Skowronski, N.; Ellicott, E. A.; Schroeder, W.

    2016-12-01

    We have developed a wide dynamic range (24-bit) data acquisition system for collection of radiant flux density (FRFD) data from wildland fires. The data collection subsystem was designed as an Arduino `shield' and incorporates a 24-bit analog-to-digital converter, precision voltage reference, real time clock, microSD card interface, audible annuciator and interface for various digital communication interfaces (RS232, I2C, SPI, etc.). The complete radiometer system consists of our custom-designed `shield', a commercially available Arduino MEGA computer circuit board and a thermopile sensor -amplifier daughter board. Software design and development is greatly assisted by the availability of a library of public-domain, user-implemented software. The daughter board houses a 5-band radiometer using thermopiles designed for this experiment (Dexter Research Corp., Dexter, MI) to allow determination of the total FRFD from the fire (using a wide band thermopile with a KRS-5 window, 0.1 - 30 um), the FRFD as would be received by an orbital asset like MODIS (3.95 um center wavelength (CWL) and 10.95 CWL, corresponding to MODIS bands 21/22 and 31, respectively) and wider bandpass (0.1-5.5 um and 8-14 um) corresponding to the FRFD recorded by `MWIR' and `LWIR' imaging systems. We required a very wide dynamic range system in order to be able to record the flux density from `cold' ground before the fire, through the `hot' flaming combustion stage, to the `cool' phase after passage of the fire front. The recording dynamic range required (with reasonable resolution at the lowest temperatures) is on the order of 106, which is not currently available in commercial instrumentation at a price point, size or feature set that is suitable for wildland fire investigations. The entire unit, along with rechargeable battery power supply is housed in a fireproof aluminum chassis box, which is then mounted on a mast at a height of 5 - 7 m above the fireground floor. We will report initial

  14. A wide dynamic range multi-channel preamplifier/shaper ASIC family for universal low power applications

    CERN Document Server

    Baturitsky, M A; Tchekhovski, V A; Zamiatin, N I

    2003-01-01

    A universal ASIC family for intermediate energy physics detectors has been designed using a bipolar/JFET technology. The family consists of two 8-channel charge-sensitive preamplifiers (CSP) ZENIT-A2, ZENIT-A3 and a shaper ZENIT-B. The values of switched gain of both CSPs are 80 and 240 mV/pC for ZENIT-A2 and 500 and 1000 mV/pC for ZENIT-A3 with channel-to-channel non-identity not more than +-5%. The CSPs can operate with input capacitance up to 300 pF for low gain and 150 pF for high gain mode. The input signal dynamic range of the shaper is matched to the outputs of both CSPs. The shaper has fast and slow outputs. The CSPs have a power consumption of 13 mW/channel; the shaper of 44 mW/channel.

  15. A wide dynamic range multi-channel preamplifier/shaper ASIC family for universal low power applications

    Energy Technology Data Exchange (ETDEWEB)

    Baturitsky, M.A. E-mail: batur@inp.minsk.by; Dvornikov, O.V.; Tchekhovski, V.A.; Zamiatin, N.I

    2003-01-01

    A universal ASIC family for intermediate energy physics detectors has been designed using a bipolar/JFET technology. The family consists of two 8-channel charge-sensitive preamplifiers (CSP) ZENIT-A2, ZENIT-A3 and a shaper ZENIT-B. The values of switched gain of both CSPs are 80 and 240 mV/pC for ZENIT-A2 and 500 and 1000 mV/pC for ZENIT-A3 with channel-to-channel non-identity not more than {+-}5%. The CSPs can operate with input capacitance up to 300 pF for low gain and 150 pF for high gain mode. The input signal dynamic range of the shaper is matched to the outputs of both CSPs. The shaper has fast and slow outputs. The CSPs have a power consumption of 13 mW/channel; the shaper of 44 mW/channel.

  16. A Dynamic Range Expansion Technique for CMOS Image Sensors with Dual Charge Storage in a Pixel and Multiple Sampling

    Directory of Open Access Journals (Sweden)

    Shinya Itoh

    2008-03-01

    Full Text Available A dynamic range expansion technique for CMOS image sensors with dual charge storage in a pixel and multiple sampling technique is presented. Each pixel contains a photodiode and a storage diode which is connected to the photodiode via a separation gate. The sensitivity of the signal charge in the storage diode can be controlled either by a separation gate which limits the charge to flow into the storage diode or by controlling the accumulation time in the storage diode. The operation of the sensitivity control with separation gate techniques is simulated and it is found that a blocking layer to the storage diode plays an important role for high controllability of sensitivity of the storage diode. A prototype chip for testing multiple short time accumulations is fabricated and measured.

  17. High-dynamic-range microscope imaging based on exposure bracketing in full-field optical coherence tomography.

    Science.gov (United States)

    Leong-Hoi, Audrey; Montgomery, Paul C; Serio, Bruno; Twardowski, Patrice; Uhring, Wilfried

    2016-04-01

    By applying the proposed high-dynamic-range (HDR) technique based on exposure bracketing, we demonstrate a meaningful reduction in the spatial noise in image frames acquired with a CCD camera so as to improve the fringe contrast in full-field optical coherence tomography (FF-OCT). This new signal processing method thus allows improved probing within transparent or semitransparent samples. The proposed method is demonstrated on 3 μm thick transparent polymer films of Mylar, which, due to their transparency, produce low contrast fringe patterns in white-light interference microscopy. High-resolution tomographic analysis is performed using the technique. After performing appropriate signal processing, resulting XZ sections are observed. Submicrometer-sized defects can be lost in the noise that is present in the CCD images. With the proposed method, we show that by increasing the signal-to-noise ratio of the images, submicrometer-sized defect structures can thus be detected.

  18. Explicit Design of FPGA-Based Coprocessors for Short-Range Force Computations in Molecular Dynamics Simulations *†

    Science.gov (United States)

    Gu, Yongfeng; VanCourt, Tom; Herbordt, Martin C.

    2008-01-01

    FPGA-based acceleration of molecular dynamics simulations (MD) has been the subject of several recent studies. The short-range force computation, which dominates the execution time, is the primary focus. Here we combine: a high level of FPGA-specific design including cell lists, systematically determined interpolation and precision, handling of exclusion, and support for MD simulations of up to 256K particles. The target system consists of a standard PC with a 2004-era COTS FPGA board. There are several innovations: new microarchitectures for several major components, including the cell list processor and the off-chip memory controller; and a novel arithmetic mode. Extensive experimentation was required to optimize precision, interpolation order, interpolation mode, table sizes, and simulation quality. We obtain a substantial speed-up over a highly tuned production MD code. PMID:19412319

  19. Explicit Design of FPGA-Based Coprocessors for Short-Range Force Computations in Molecular Dynamics Simulations.

    Science.gov (United States)

    Gu, Yongfeng; Vancourt, Tom; Herbordt, Martin C

    2008-05-01

    FPGA-based acceleration of molecular dynamics simulations (MD) has been the subject of several recent studies. The short-range force computation, which dominates the execution time, is the primary focus. Here we combine: a high level of FPGA-specific design including cell lists, systematically determined interpolation and precision, handling of exclusion, and support for MD simulations of up to 256K particles. The target system consists of a standard PC with a 2004-era COTS FPGA board. There are several innovations: new microarchitectures for several major components, including the cell list processor and the off-chip memory controller; and a novel arithmetic mode. Extensive experimentation was required to optimize precision, interpolation order, interpolation mode, table sizes, and simulation quality. We obtain a substantial speed-up over a highly tuned production MD code.

  20. Static and dynamic behaviour of a quasi 1-d Heisenberg antiferromagnet in the long-range ordered state

    International Nuclear Information System (INIS)

    Voorhoeve, J.C.

    1986-01-01

    The goal of this thesis is to clarify the dynamic properties of a one-dimensional S=1/2 isotropic Heisenberg antiferromagnet (HAFM). The physical realization chosen for this model system is CuSO 4 .5H 2 O. The experimental information about the dynamical properties of the electron spin system is obtained from longitudinal proton spin relaxation measurements. In ch.2 the experimental set up is described including the 3 He- 4 He dilution refrigerator for obtaining the required low temperatures, and the rotatable superconducting split-coil magnet. In ch.3 the problems are treated which occur when nuclear relaxation experiments are performed in the long-range order state of CuSO 4 .5H 2 O and an experimental method is described to measure the proton spin-lattice relaxation time T 1 supplying a minimum of energy to the nuclear spin system. In ch.4 continuous-wave NMR experiments on CuSO 4 .5H 2 O are described. In ch. 5 experimental results on the relaxation rate T 1 -1 above and in the vicinity of the phase transition are described and in ch.6 experimental results in the LRO state are presented and discussed. (Auth.)

  1. A Low-Power Wide Dynamic-Range Current Readout Circuit for Ion-Sensitive FET Sensors.

    Science.gov (United States)

    Son, Hyunwoo; Cho, Hwasuk; Koo, Jahyun; Ji, Youngwoo; Kim, Byungsub; Park, Hong-June; Sim, Jae-Yoon

    2017-06-01

    This paper presents an amplifier-less and digital-intensive current-to-digital converter for ion-sensitive FET sensors. Capacitance on the input node is utilized as a residue accumulator, and a clocked comparator is followed for quantization. Without any continuous-time feedback circuit, the converter performs a first-order noise shaping of the quantization error. In order to minimize static power consumption, the proposed circuit employs a single-ended current-steering digital-to-analog converter which flows only the same current as the input. By adopting a switching noise averaging algorithm, our dynamic element matching not only mitigates mismatch of current sources in the current-steering DAC, but also makes the effect of dynamic switching noise become an input-independent constant. The implemented circuit in 0.35 μm CMOS converts the current input with a range of 2.8 μ A to 15 b digital output in about 4 ms, showing a DNL of +0.24/-0.25 LSB and an INL of + 1.98/-1.98 LSB while consuming 16.8 μW.

  2. BF3-doped polyaniline: A novel conducting polymer

    Indian Academy of Sciences (India)

    During the past two decades, both fundamental and applied research in conducting polymers has grown enormously [1]. Polyaniline (PANI) owing to its ease of synthe- sis, remarkable environmental stability, and high conductivity in the doped form, has remained one of the most thoroughly studied conducting polymers.

  3. BF3-doped polyaniline: A novel conducting polymer

    Indian Academy of Sciences (India)

    Abstract. We review the unusual structural, transport and magnetic properties of highly conducting polyaniline, doped with boron trifluoride. Our studies establish the unique conducting state of this system, which is in distinct contrast with the conventional proton-doped polyaniline samples.

  4. Amorphous silicon films doped with BF3 and PF5

    International Nuclear Information System (INIS)

    Ortiz, A.; Muhl, S.; Sanchez, A.; Monroy, R.; Pickin, W.

    1984-01-01

    By using gaseous discharge process, thin films of hydrogenated amorphous silicon (a-Si:H) were produced. This process consists of Silane (SiH 4 ) decomposition at low pressure, in a chamber. (A.C.A.S.) [pt

  5. Spatial and temporal dynamics of fucoid populations (Ascophyllum nodosum and Fucus serratus: a comparison between central and range edge populations.

    Directory of Open Access Journals (Sweden)

    Rita M Araújo

    Full Text Available Persistence of populations at range edges relies on local population dynamics and fitness, in the case of geographically isolated populations of species with low dispersal potential. Focusing on spatial variations in demography helps to predict the long-term capability for persistence of populations across the geographical range of species' distribution. The demography of two ecological and phylogenetically close macroalgal species with different life history characteristics was investigated by using stochastic, stage-based matrix models. Populations of Ascophyllum nodosum and Fucus serratus were sampled for up to 4 years at central locations in France and at their southern range limits in Portugal. The stochastic population growth rate (λ(s of A. nodosum was lower and more variable in central than in southern sites whilst for F. serratus this trend was reversed with λ(s much lower and more variable in southern than in central populations. Individuals were larger in central than in southern populations for both species, which was reflected in the lower transition probabilities of individuals to larger size classes and higher probability of shrinkage in the southern populations. In both central and southern populations elasticity analysis (proportional sensitivity of population growth rate showed that fertility elements had a small contribution to λ(s that was more sensitive to changes in matrix transitions corresponding to survival. The highest elasticities were found for loop transitions in A. nodosum and for growth to larger size classes in F. serratus. Sensitivity analysis showed high selective pressure on individual growth for both species at both locations. The results of this study highlight the deterministic role of species-specific life-history traits in population demography across the geographical range of species. Additionally, this study demonstrates that individuals' life-transitions differ in vulnerability to environmental

  6. Cooling rate and size effects on the medium-range structure of multicomponent oxide glasses simulated by molecular dynamics

    International Nuclear Information System (INIS)

    Tilocca, Antonio

    2013-01-01

    A set of molecular dynamics simulations were performed to investigate the effect of cooling rate and system size on the medium-range structure of melt-derived multicomponent silicate glasses, represented by the quaternary 45S5 Bioglass composition. Given the significant impact of the glass degradation on applications of these materials in biomedicine and nuclear waste disposal, bulk structural features which directly affect the glass dissolution process are of particular interest. Connectivity of the silicate matrix, ion clustering and nanosegregation, distribution of ring and chain structural patterns represent critical features in this context, which can be directly extracted from the models. A key issue is represented by the effect of the computational approach on the corresponding glass models, especially in light of recent indications questioning the suitability of conventional MD approaches (that is, involving melt-and-quench of systems containing ∼10 3 atoms at cooling rates of 5-10 K/ps) when applied to model these glasses. The analysis presented here compares MD models obtained with conventional and nonconventional cooling rates and system sizes, highlighting the trend and range of convergence of specific structural features in the medium range. The present results show that time-consuming computational approaches involving much lower cooling rates and/or significantly larger system sizes are in most cases not necessary in order to obtain a reliable description of the medium-range structure of multicomponent glasses. We identify the convergence range for specific properties and use them to discuss models of several glass compositions for which a possible influence of cooling-rate or size effects had been previously hypothesized. The trends highlighted here represent an important reference to obtain reliable models of multicomponent glasses and extract converged medium-range structural features which affect the glass degradation and thus their application

  7. Effect of the speed of a single-channel dynamic range compressor on intelligibility in a competing speech task

    Science.gov (United States)

    Stone, Michael A.; Moore, Brian C. J.

    2003-08-01

    Using a ``noise-vocoder'' cochlear implant simulator [Shannon et al., Science 270, 303-304 (1995)], the effect of the speed of dynamic range compression on speech intelligibility was assessed, using normal-hearing subjects. The target speech had a level 5 dB above that of the competing speech. Initially, baseline performance was measured with no compression active, using between 4 and 16 processing channels. Then, performance was measured using a fast-acting compressor and a slow-acting compressor, each operating prior to the vocoder simulation. The fast system produced significant gain variation over syllabic timescales. The slow system produced significant gain variation only over the timescale of sentences. With no compression active, about six channels were necessary to achieve 50% correct identification of words in sentences. Sixteen channels produced near-maximum performance. Slow-acting compression produced no significant degradation relative to the baseline. However, fast-acting compression consistently reduced performance relative to that for the baseline, over a wide range of performance levels. It is suggested that fast-acting compression degrades performance for two reasons: (1) because it introduces correlated fluctuations in amplitude in different frequency bands, which tends to produce perceptual fusion of the target and background sounds and (2) because it reduces amplitude modulation depth and intensity contrasts.

  8. Himalayan ibex (Capra ibex sibirica habitat suitability and range resource dynamics in the Central Karakorum National Park, Pakistan

    Directory of Open Access Journals (Sweden)

    Garee Khan

    2016-07-01

    Full Text Available The study investigates Himalayan ibex (Capra ibex sibirica and their range resource condition within the preferred habitat in the Central Karakoram National Park, Pakistan. We apply ecological niche factor analysis (ENFA using 110 ibex sighting data and 6 key biophysical variables describing the habitat conditions and produce habitat suitability and maps with GIS and statistical tool (BioMapper. The modeling results of specialization factor shows some limitation for ibex over the use of slope, elevation, vegetation types and ruggedness. The habitat area selection for the ibex is adjusted to the ibex friendly habitat available conditions. The model results predicted suitable habitat for ibex in certain places, where field observation was never recorded. The range resource dynamics depict a large area that comes under the alpine meadows has the highest seasonal productivity, assessed by remote sensing based fortnightly vegetation condition data of the last 11 years. These meadows are showing browning trend over the years, attributable to grazing practices or climate conditions. At lower elevation, there are limited areas with suitable dry steppes, which may cause stress on ibex, especially during winter.

  9. A Novel Realization of Low-Power and Low-Distortion Multiplier Circuit with Improved Dynamic Range

    Directory of Open Access Journals (Sweden)

    Ali Naderi Saatlo

    2017-01-01

    Full Text Available A novel topology of four-quadrant analog multiplier circuit is presented in this paper. The voltage mode technique is employed to design the circuit in CMOS technology. The dynamic input and output ranges of the circuit are improved owing to the fact that the circuit works in the saturation region not in weak inversion. Also the proposed multiplier is suitable for low voltage operation and its power consumption is relatively low. In order to verify the performance of the proposed circuit, performance of the circuit affected by second order effects including transistor mismatch and mobility reduction is analyzed in detail. It will be shown that any conceivable mismatch in the transistor parameters leads to second harmonic distortion. Additionally, the effect of mobility reduction in the third harmonic distortion will be computed. In order to simulate the circuit, Cadence and HSPICE software are used with TSMC level 49 (BSIM3v3 parameters for 0.18 μm CMOS technology, where under supply voltage of 1.5 V, total power consumption is 44 µW, the corresponding average nonlinearity remains as low as 1 %, and the input range of the circuit is ± 400 mV.

  10. Nonlinear complexity of random visibility graph and Lempel-Ziv on multitype range-intensity interacting financial dynamics

    Science.gov (United States)

    Zhang, Yali; Wang, Jun

    2017-09-01

    In an attempt to investigate the nonlinear complex evolution of financial dynamics, a new financial price model - the multitype range-intensity contact (MRIC) financial model, is developed based on the multitype range-intensity interacting contact system, in which the interaction and transmission of different types of investment attitudes in a stock market are simulated by viruses spreading. Two new random visibility graph (VG) based analyses and Lempel-Ziv complexity (LZC) are applied to study the complex behaviors of return time series and the corresponding random sorted series. The VG method is the complex network theory, and the LZC is a non-parametric measure of complexity reflecting the rate of new pattern generation of a series. In this work, the real stock market indices are considered to be comparatively studied with the simulation data of the proposed model. Further, the numerical empirical study shows the similar complexity behaviors between the model and the real markets, the research confirms that the financial model is reasonable to some extent.

  11. The Effective Dynamic Ranges for Glaucomatous Visual Field Progression With Standard Automated Perimetry and Stimulus Sizes III and V.

    Science.gov (United States)

    Wall, Michael; Zamba, Gideon K D; Artes, Paul H

    2018-01-01

    It has been shown that threshold estimates below approximately 20 dB have little effect on the ability to detect visual field progression in glaucoma. We aimed to compare stimulus size V to stimulus size III, in areas of visual damage, to confirm these findings by using (1) a different dataset, (2) different techniques of progression analysis, and (3) an analysis to evaluate the effect of censoring on mean deviation (MD). In the Iowa Variability in Perimetry Study, 120 glaucoma subjects were tested every 6 months for 4 years with size III SITA Standard and size V Full Threshold. Progression was determined with three complementary techniques: pointwise linear regression (PLR), permutation of PLR, and linear regression of the MD index. All analyses were repeated on "censored'' datasets in which threshold estimates below a given criterion value were set to equal the criterion value. Our analyses confirmed previous observations that threshold estimates below 20 dB contribute much less to visual field progression than estimates above this range. These findings were broadly similar with stimulus sizes III and V. Censoring of threshold values < 20 dB has relatively little impact on the rates of visual field progression in patients with mild to moderate glaucoma. Size V, which has lower retest variability, performs at least as well as size III for longitudinal glaucoma progression analysis and appears to have a larger useful dynamic range owing to the upper sensitivity limit being higher.

  12. Color-XHDR - A Compact High-Speed Color Extreme High Dynamic Range Video Capability for Rocket Engine Testing, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative Imaging and Research proposes to develop a 21st Century color, high-speed extreme high dynamic range (Color-XHDR) video recording technology that will...

  13. Color-XHDR - A Compact High-Speed Color Extreme High Dynamic Range Video Capability for Rocket Engine Testing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative Imaging and Research (I2R) proposes to develop a 21st Century high-speed, color extreme high dynamic range (Color-XHDR) video recording system that will...

  14. The Effect of Dynamic Knee Valgus during Overhead Squat on Distal and Proximal Knee Joints Muscle Strength and Range of Motion in Basketball Player

    Directory of Open Access Journals (Sweden)

    Hemn Mohammadi

    2018-03-01

    Conclusions: The results showed that the dynamic knee valgus group exhibited tight and weak ankle musculature, and as appeared, training interventions focused on improving strength and range of motion of the ankle can improve lower extremity kinematics of during overhead squat and modify dynamic knee valgus.

  15. Ab initio molecular dynamics study of fluid H2O-CO2 mixture in broad pressure-temperature range

    Directory of Open Access Journals (Sweden)

    Jie Fu

    2017-11-01

    Full Text Available Properties of H2O and CO2 fluid and their mixtures under extreme pressures and temperatures are poorly known yet critically important in a number of applications. Several hundreds of first-principles molecular dynamics (FPMD runs have been performed to obtain the pressure-volume-temperature (P-V-T data on supercritical H2O, CO2, and H2O-CO2 mixtures. The pressure-temperature (P-T range are from 0.5 GPa to 104 GPa (48.5 GPa for CO2 and from 600 K to 4000 K. Based on these data, we evaluate several existing equations of state (EOS for the fluid H2O, CO2, and H2O-CO2 mixture. The results show that the EOS for H2O from Belonoshko et al. [Geochim. Cosmochim. Acta 55, 381–387; Geochim. Cosmochim. Acta 55, 3191–3208; Geochim. Cosmochim. Acta 56, 3611–3626; Comput. Geosci. 18, 1267–1269] not only can be used in the studied P-T range but also is accurate enough to be used for prediction of P-V-T data. In addition, IAPWS-95 EOS for H2O shows excellent extrapolation behavior beyond 1.0 GPa and 1273 K. However, for the case of CO2, none of the existing EOS produces data in agreement with the FPMD results. We created new EOS for CO2. The precision of the new EOS is tested by comparison to the calculated P-V-T data, fugacity coefficient of the CO2 fluid derived from high P-T experimental data as well as to the (very scarce experimental volumetric data in the high P-T range. On the basis of our FPMD data we created a new EOS for H2O-CO2 mixture. The new EOS for the mixture is in reasonable agreement with experimental data.

  16. Ab initio molecular dynamics study of fluid H2O-CO2 mixture in broad pressure-temperature range

    Science.gov (United States)

    Fu, Jie; Zhao, Jijun; Plyasunov, Andrey V.; Belonoshko, Anatoly B.

    2017-11-01

    Properties of H2O and CO2 fluid and their mixtures under extreme pressures and temperatures are poorly known yet critically important in a number of applications. Several hundreds of first-principles molecular dynamics (FPMD) runs have been performed to obtain the pressure-volume-temperature (P-V-T) data on supercritical H2O, CO2, and H2O-CO2 mixtures. The pressure-temperature (P-T) range are from 0.5 GPa to 104 GPa (48.5 GPa for CO2) and from 600 K to 4000 K. Based on these data, we evaluate several existing equations of state (EOS) for the fluid H2O, CO2, and H2O-CO2 mixture. The results show that the EOS for H2O from Belonoshko et al. [Geochim. Cosmochim. Acta 55, 381-387; Geochim. Cosmochim. Acta 55, 3191-3208; Geochim. Cosmochim. Acta 56, 3611-3626; Comput. Geosci. 18, 1267-1269] not only can be used in the studied P-T range but also is accurate enough to be used for prediction of P-V-T data. In addition, IAPWS-95 EOS for H2O shows excellent extrapolation behavior beyond 1.0 GPa and 1273 K. However, for the case of CO2, none of the existing EOS produces data in agreement with the FPMD results. We created new EOS for CO2. The precision of the new EOS is tested by comparison to the calculated P-V-T data, fugacity coefficient of the CO2 fluid derived from high P-T experimental data as well as to the (very scarce) experimental volumetric data in the high P-T range. On the basis of our FPMD data we created a new EOS for H2O-CO2 mixture. The new EOS for the mixture is in reasonable agreement with experimental data.

  17. High resolution mapping of riffle-pool dynamics based on ADCP and close-range remote sensing data

    Science.gov (United States)

    Salmela, Jouni; Kasvi, Elina; Alho, Petteri

    2017-04-01

    Present development of mobile laser scanning (MLS) and close-range photogrammetry with unmanned aerial vehicle (UAV) enable us to create seamless digital elevation models (DEMs) of the riverine environment. Remote-controlled flow measurement platforms have also improved spatio-temporal resolution of the flow field data. In this study, acoustic Doppler current profiler (ADCP) attached to remote-controlled mini-boat, UAV-based bathymetry and MLS techniques were utilized to create the high-resolution DEMs of the river channel. These high-resolution measurements can be used in many fluvial applications such as computational fluid dynamics, channel change detection, habitat mapping or hydro-electric power plant planning. In this study we aim: 1) to analyze morphological changes of river channel especially riffle and pool formations based on fine-scale DEMs and ADCP measurements, 2) to analyze flow fields and their effect on morphological changes. The interest was mainly focused on reach-scale riffle-pool dynamics within two-year period of 2013 and 2014. The study was performed in sub-arctic meandering Pulmankijoki River located in Northern Finland. The river itself has shallow and clear water and sandy bed sediment. Discharge remains typically below 10 m3s-1 most of the year but during snow melt period in spring the discharge may exceed 70 m3s-1. We compared DEMs and ADCP measurements to understand both magnitude and spatio-temporal change of the river bed. Models were accurate enough to study bed form changes and locations and persistence of riffles and pools. We analyzed their locations with relation to flow during the peak and low discharge. Our demonstrated method has improved significantly spatio-temporal resolution of riverine DEMs compared to other cross-sectional and photogrammetry based models. Together with flow field measurements we gained better understanding of riverbed-water interaction

  18. Dynamic properties of Indiana, Fort Knox and Utah test range limestones and Danby Marble over the stress range 1 to 20 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Furnish, M.D.

    1994-12-01

    The responses of the following carbonate materials to shock loading and release have been measured: Indiana limestone (18% porosity; saturated and dry), Jeffersonville/Louisville Limestones (Fort Knox limestone) (variable dolomitization, low porosity), Danby Marble (essentially pure calcite; low porosity), and a limestone from the Utah Test and Training Range (low porosity, with 22% silica). Various experimental configurations were used, some optimized to yield detailed waveform information, others to yield a clean combination of Hugoniot states and release paths. All made use of velocity interferometry as a primary diagnostic. The stress range of 0 - 20 GPa was probed (in most cases, emphasizing the stress range 0 -10 GPa). The primary physical processes observed in this stress regime were material strength, porosity, and polymorphic phase transitions between the CaCO{sub 3} phases I, II, III and VI. Hydration was also a significant reaction under certain conditions. The Indiana Limestone studies in particular represent a significant addition to the low-pressure database for porous limestone. Temperature dependence and the effect of freezing were assessed for the Fort Knox limestone. Experimental parameters and detailed results are provided for the 42 impact tests in this series.

  19. Eliminating Glutamatergic Input onto Horizontal Cells Changes the Dynamic Range and Receptive Field Organization of Mouse Retinal Ganglion Cells.

    Science.gov (United States)

    Ströh, Sebastian; Puller, Christian; Swirski, Sebastian; Hölzel, Maj-Britt; van der Linde, Lea I S; Segelken, Jasmin; Schultz, Konrad; Block, Christoph; Monyer, Hannah; Willecke, Klaus; Weiler, Reto; Greschner, Martin; Janssen-Bienhold, Ulrike; Dedek, Karin

    2018-02-21

    In the mammalian retina, horizontal cells receive glutamatergic inputs from many rod and cone photoreceptors and return feedback signals to them, thereby changing photoreceptor glutamate release in a light-dependent manner. Horizontal cells also provide feedforward signals to bipolar cells. It is unclear, however, how horizontal cell signals also affect the temporal, spatial, and contrast tuning in retinal output neurons, the ganglion cells. To study this, we generated a genetically modified mouse line in which we eliminated the light dependency of feedback by deleting glutamate receptors from mouse horizontal cells. This genetic modification allowed us to investigate the impact of horizontal cells on ganglion cell signaling independent of the actual mode of feedback in the outer retina and without pharmacological manipulation of signal transmission. In control and genetically modified mice (both sexes), we recorded the light responses of transient OFF-α retinal ganglion cells in the intact retina. Excitatory postsynaptic currents (EPSCs) were reduced and the cells were tuned to lower temporal frequencies and higher contrasts, presumably because photoreceptor output was attenuated. Moreover, receptive fields of recorded cells showed a significantly altered surround structure. Our data thus suggest that horizontal cells are responsible for adjusting the dynamic range of retinal ganglion cells and, together with amacrine cells, contribute to the center/surround organization of ganglion cell receptive fields in the mouse. SIGNIFICANCE STATEMENT Horizontal cells represent a major neuronal class in the mammalian retina and provide lateral feedback and feedforward signals to photoreceptors and bipolar cells, respectively. The mode of signal transmission remains controversial and, moreover, the contribution of horizontal cells to visual processing is still elusive. To address the question of how horizontal cells affect retinal output signals, we recorded the light

  20. The effect of static stretch and dynamic range of motion training on the flexibility of the hamstring muscles.

    Science.gov (United States)

    Bandy, W D; Irion, J M; Briggler, M

    1998-04-01

    To date, limited information exists describing a relatively new stretching technique, dynamic range of motion (DROM). The purpose of this study was to compare the effects of DROM with static stretch on hamstring flexibility. Fifty-eight subjects, ranging in age from 21 to 41 years and with limited hamstring flexibility (defined as 30 degrees loss of knee extension measured with the femur held at 90 degrees of hip flexion), were randomly assigned to one of three groups. One group performed DROM 5 days a week by lying supine with the hip held in 90 degrees of flexion. The subject then actively moved the leg into knee extension (5 seconds), held the leg in end range knee extension for 5 seconds, and then slowly lowered the leg to the initial position (5 seconds). These movements were performed six times per session (30 seconds of total actual stretching time). The second group performed one 30-second static stretch, 5 days per week. The third group served as a control group and did not stretch. Before and after 6 weeks of training, flexibility of the hamstring muscles was determined in all three groups by measuring knee extension range of motion (ROM) with the femur maintained in 90 degrees of hip flexion. Data were analyzed with a 2 x 3 (test x group) two-way analysis of variance (ANOVA) with repeated measures on one variable (test) and appropriate post hoc analyses. The results of the two-way ANOVA revealed a significant interaction. Further statistical post hoc analysis of data to interpret the interaction revealed significant differences between the control group (gain = 0.70 degree) and both stretching groups, as well as a significant difference between the static stretch group (gain = 11.42 degrees) and the DROM group (gain = 4.26 degrees). The results of this study suggest that, although both static stretch and DROM will increase hamstring flexibility, a 30-second static stretch was more effective than the newer technique, DROM, for enhancing flexibility. Given

  1. Simulating range-wide population and breeding habitat dynamics for an endangered woodland warbler in the face of uncertainty

    Science.gov (United States)

    Adam Duarte,; Hatfield, Jeffrey; Todd M. Swannack,; Michael R. J. Forstner,; M. Clay Green,; Floyd W. Weckerly,

    2015-01-01

    Population viability analyses provide a quantitative approach that seeks to predict the possible future status of a species of interest under different scenarios and, therefore, can be important components of large-scale species’ conservation programs. We created a model and simulated range-wide population and breeding habitat dynamics for an endangered woodland warbler, the golden-cheeked warbler (Setophaga chrysoparia). Habitat-transition probabilities were estimated across the warbler's breeding range by combining National Land Cover Database imagery with multistate modeling. Using these estimates, along with recently published demographic estimates, we examined if the species can remain viable into the future given the current conditions. Lastly, we evaluated if protecting a greater amount of habitat would increase the number of warblers that can be supported in the future by systematically increasing the amount of protected habitat and comparing the estimated terminal carrying capacity at the end of 50 years of simulated habitat change. The estimated habitat-transition probabilities supported the hypothesis that habitat transitions are unidirectional, whereby habitat is more likely to diminish than regenerate. The model results indicated population viability could be achieved under current conditions, depending on dispersal. However, there is considerable uncertainty associated with the population projections due to parametric uncertainty. Model results suggested that increasing the amount of protected lands would have a substantial impact on terminal carrying capacities at the end of a 50-year simulation. Notably, this study identifies the need for collecting the data required to estimate demographic parameters in relation to changes in habitat metrics and population density in multiple regions, and highlights the importance of establishing a common definition of what constitutes protected habitat, what management goals are suitable within those protected

  2. Imaging X-ray detector front-end with high dynamic range: IDeF-X HD

    Science.gov (United States)

    Gevin, O.; Lemaire, O.; Lugiez, F.; Michalowska, A.; Baron, P.; Limousin, O.; Delagnes, E.

    2012-12-01

    Presented circuit, IDeF-X HD (Imaging Detector Front-end) is a member of the IDeF-X ASICs family for space applications. It has been optimized for a half millimeter pitch CdTe or CdZnTe pixelated detector arranged in 16×16 array. It is aimed to operate in the hard X-ray range from few keV up to 250 keV or more. The ASIC has been realized in AMS 0.35 μm CMOS process. The IDeF-X HD is a 32 channel analog front-end with self-triggering capability. The architecture of the analog channel includes a chain of charge sensitive amplifier with continuous reset system and non-stationary noise suppressor, adjustable gain stage, pole-zero cancellation stage, adjustable shaping time low pass filter, baseline holder and peak detector with discriminator. The power consumption of the IDeF-X HD is 800 μW per channel. With the in-channel variable gain stage the nominal 250 keV dynamic range of the ASIC can be extended up to 1 MeV anticipating future applications using thick sensors. Measuring the noise performance without a detector at the input with minimized leakage current (programmable) at the input, we achieved ENC of 33 electrons rms at 10.7 μs peak time. Measurements with CdTe detector show good energy resolution FWHM of 1.1 keV at 60 keV and 4.3 keV at 662 keV with detection threshold below 4 keV. In addition, an absolute temperature sensor has been integrated with resolution of 1.5 °C.

  3. Optimized lighting method of applying shaped-function signal for increasing the dynamic range of LED-multispectral imaging system

    Science.gov (United States)

    Yang, Xue; Hu, Yajia; Li, Gang; Lin, Ling

    2018-02-01

    This paper proposes an optimized lighting method of applying a shaped-function signal for increasing the dynamic range of light emitting diode (LED)-multispectral imaging system. The optimized lighting method is based on the linear response zone of the analog-to-digital conversion (ADC) and the spectral response of the camera. The auxiliary light at a higher sensitivity-camera area is introduced to increase the A/D quantization levels that are within the linear response zone of ADC and improve the signal-to-noise ratio. The active light is modulated by the shaped-function signal to improve the gray-scale resolution of the image. And the auxiliary light is modulated by the constant intensity signal, which is easy to acquire the images under the active light irradiation. The least square method is employed to precisely extract the desired images. One wavelength in multispectral imaging based on LED illumination was taken as an example. It has been proven by experiments that the gray-scale resolution and the accuracy of information of the images acquired by the proposed method were both significantly improved. The optimum method opens up avenues for the hyperspectral imaging of biological tissue.

  4. Additive N-step Markov chains as prototype model of symbolic stochastic dynamical systems with long-range correlations

    International Nuclear Information System (INIS)

    Mayzelis, Z.A.; Apostolov, S.S.; Melnyk, S.S.; Usatenko, O.V.; Yampol'skii, V.A.

    2007-01-01

    A theory of symbolic dynamic systems with long-range correlations based on the consideration of the binary N-step Markov chains developed earlier in Phys Rev Lett 2003;90:110601 is generalized to the biased case (non-equal numbers of zeros and unities in the chain). In the model, the conditional probability that the ith symbol in the chain equals zero (or unity) is a linear function of the number of unities (zeros) among the preceding N symbols. The correlation and distribution functions as well as the variance of number of symbols in the words of arbitrary length L are obtained analytically and verified by numerical simulations. A self-similarity of the studied stochastic process is revealed and the similarity group transformation of the chain parameters is presented. The diffusion Fokker-Planck equation governing the distribution function of the L-words is explored. If the persistent correlations are not extremely strong, the distribution function is shown to be the Gaussian with the variance being nonlinearly dependent on L. An equation connecting the memory and correlation function of the additive Markov chain is presented. This equation allows reconstructing a memory function using a correlation function of the system. Effectiveness and robustness of the proposed method is demonstrated by simple model examples. Memory functions of concrete coarse-grained literary texts are found and their universal power-law behavior at long distances is revealed

  5. Additive N-step Markov chains as prototype model of symbolic stochastic dynamical systems with long-range correlations

    Energy Technology Data Exchange (ETDEWEB)

    Mayzelis, Z.A. [Department of Physics, Kharkov National University, 4 Svoboda Sq., Kharkov 61077 (Ukraine); Apostolov, S.S. [Department of Physics, Kharkov National University, 4 Svoboda Sq., Kharkov 61077 (Ukraine); Melnyk, S.S. [A. Ya. Usikov Institute for Radiophysics and Electronics, Ukrainian Academy of Science, 12 Proskura Street, 61085 Kharkov (Ukraine); Usatenko, O.V. [A. Ya. Usikov Institute for Radiophysics and Electronics, Ukrainian Academy of Science, 12 Proskura Street, 61085 Kharkov (Ukraine)]. E-mail: usatenko@ire.kharkov.ua; Yampol' skii, V.A. [A. Ya. Usikov Institute for Radiophysics and Electronics, Ukrainian Academy of Science, 12 Proskura Street, 61085 Kharkov (Ukraine)

    2007-10-15

    A theory of symbolic dynamic systems with long-range correlations based on the consideration of the binary N-step Markov chains developed earlier in Phys Rev Lett 2003;90:110601 is generalized to the biased case (non-equal numbers of zeros and unities in the chain). In the model, the conditional probability that the ith symbol in the chain equals zero (or unity) is a linear function of the number of unities (zeros) among the preceding N symbols. The correlation and distribution functions as well as the variance of number of symbols in the words of arbitrary length L are obtained analytically and verified by numerical simulations. A self-similarity of the studied stochastic process is revealed and the similarity group transformation of the chain parameters is presented. The diffusion Fokker-Planck equation governing the distribution function of the L-words is explored. If the persistent correlations are not extremely strong, the distribution function is shown to be the Gaussian with the variance being nonlinearly dependent on L. An equation connecting the memory and correlation function of the additive Markov chain is presented. This equation allows reconstructing a memory function using a correlation function of the system. Effectiveness and robustness of the proposed method is demonstrated by simple model examples. Memory functions of concrete coarse-grained literary texts are found and their universal power-law behavior at long distances is revealed.

  6. Correlated continuous time random walks: combining scale-invariance with long-range memory for spatial and temporal dynamics

    International Nuclear Information System (INIS)

    Schulz, Johannes H P; Chechkin, Aleksei V; Metzler, Ralf

    2013-01-01

    Standard continuous time random walk (CTRW) models are renewal processes in the sense that at each jump a new, independent pair of jump length and waiting time are chosen. Globally, anomalous diffusion emerges through scale-free forms of the jump length and/or waiting time distributions by virtue of the generalized central limit theorem. Here we present a modified version of recently proposed correlated CTRW processes, where we incorporate a power-law correlated noise on the level of both jump length and waiting time dynamics. We obtain a very general stochastic model, that encompasses key features of several paradigmatic models of anomalous diffusion: discontinuous, scale-free displacements as in Lévy flights, scale-free waiting times as in subdiffusive CTRWs, and the long-range temporal correlations of fractional Brownian motion (FBM). We derive the exact solutions for the single-time probability density functions and extract the scaling behaviours. Interestingly, we find that different combinations of the model parameters lead to indistinguishable shapes of the emerging probability density functions and identical scaling laws. Our model will be useful for describing recent experimental single particle tracking data that feature a combination of CTRW and FBM properties. (paper)

  7. 2.5 Gbit/s Optical Receiver Front-End Circuit with High Sensitivity and Wide Dynamic Range

    Science.gov (United States)

    Zhu, Tiezhu; Mo, Taishan; Ye, Tianchun

    2017-12-01

    An optical receiver front-end circuit is designed for passive optical network and fabricated in a 0.18 um CMOS technology. The whole circuit consists of a transimpedance amplifier (TIA), a single-ended to differential amplifier and an output driver. The TIA employs a cascode stage as the input stage and auxiliary amplifier to reduce the miller effect. Current injecting technique is employed to enlarge the input transistor's transconductance, optimize the noise performance and overcome the lack of voltage headroom. To achieve a wide dynamic range, an automatic gain control circuit with self-adaptive function is proposed. Experiment results show an optical sensitivity of -28 dBm for a bit error rate of 10-10 at 2.5 Gbit/s and a maxim input optical power of 2 dBm using an external photodiode. The chip occupies an area of 1×0.9 mm2 and consumes around 30 mW from single 1.8 V supply. The front-end circuit can be used in various optical receivers.

  8. Spinal cord injury triggers sensitization of wide dynamic range dorsal horn neurons in segments rostral to the injury.

    Science.gov (United States)

    Zhang, Haijun; Xie, Wenrui; Xie, Yikuan

    2005-09-07

    A spinal cord injury (SCI) was produced in adult rats by complete spinal cord transection at L6-S1. Neuropathic pain behaviors similar to the chronic central pain (CCP) syndrome in human, such as thermal hyperalgesia, mechanical allodynia and autotomy, were present in these rats after spinal cord injury. Meanwhile, wide dynamic range (WDR) neurons recorded in the spinal dorsal horn rostral to the lesion responded as high frequency of spontaneous activities, long duration of after-discharges to noxious electrical stimuli and an augmented wind-up to 0.5 Hz stimuli. By using bupivacaine powder, a sodium channel blocker, at the locus of transection immediate after nerve injury, the chronic pain behaviors were prevented; the hyperexcitability of WDR neurons was also substantially reduced. It is suggested that spinal cord transection induces the CCP syndromes, which may be evoked and maintained by the hyperexcitability in WDR neurons rostrally. Reducing the neuronal activity at the site of lesion following injury may prevent the development of CCP after SCI.

  9. Dynamic model for kinesin-mediated long-range transport and its local traffic jam caused by tau proteins

    Science.gov (United States)

    Nam, Woochul; Epureanu, Bogdan I.

    2017-01-01

    In neurons, several intracellular cargoes are transported by motor proteins (kinesins) which walk on microtubules (MTs). However, kinesins can possibly unbind from the MTs before they reach their destinations. The unbound kinesins randomly diffuse in neurons until they bind to MTs. Then, they walk again along the MTs to continue their tasks. Kinesins repeat this cycle of motion until they transport their cargoes to the destinations. However, most previous models mainly focused on the motion of kinesins when they walk on MTs. Thus, a new model is required to encompass the various types of kinesin motion. We developed a comprehensive model and studied the long-range axonal transport of neurons using the model. To enhance reliability of the model, it was constructed based on multiphysics on kinesin motion (i.e., chemical kinetics, diffusion, fluid dynamics, nonlinear dynamics, and stochastic characteristics). Also, parameter values for kinesin motions are carefully obtained by comparing the model predictions and several experimental observations. The axonal transport can be degraded when a large number of binding sites on MTs are blocked by excessive tau proteins. By considering the interference between walking kinesins and tau molecules on MTs, effects of tau proteins on the axonal transport are studied. One of the meaningful predictions obtained from the model is that the velocity is not an effective metric to estimate the degradation of the transport because the decrease in velocity is not noticeable when the concentration of tau protein is not high. However, our model shows that the transport locally changes near tau molecules on MTs even when the change in the velocity is not significant. Thus, a statistical method is proposed to detect this local change effectively. The advantage of this method is that a value obtained from this method is highly sensitive to the concentration of tau protein. Another benefit of this method is that this highly sensitive value can

  10. Dynamic range of Nef-mediated evasion of HLA class II-restricted immune responses in early HIV-1 infection.

    Science.gov (United States)

    Mahiti, Macdonald; Brumme, Zabrina L; Jessen, Heiko; Brockman, Mark A; Ueno, Takamasa

    2015-07-31

    HLA class II-restricted CD4(+) T lymphocytes play an important role in controlling HIV-1 replication, especially in the acute/early infection stage. But, HIV-1 Nef counteracts this immune response by down-regulating HLA-DR and up-regulating the invariant chain associated with immature HLA-II (Ii). Although functional heterogeneity of various Nef activities, including down-regulation of HLA class I (HLA-I), is well documented, our understanding of Nef-mediated evasion of HLA-II-restricted immune responses during acute/early infection remains limited. Here, we examined the ability of Nef clones from 47 subjects with acute/early progressive infection and 46 subjects with chronic progressive infection to up-regulate Ii and down-regulate HLA-DR and HLA-I from the surface of HIV-infected cells. HLA-I down-regulation function was preserved among acute/early Nef clones, whereas both HLA-DR down-regulation and Ii up-regulation functions displayed relatively broad dynamic ranges. Nef's ability to down-regulate HLA-DR and up-regulate Ii correlated positively at this stage, suggesting they are functionally linked in vivo. Acute/early Nef clones also exhibited higher HLA-DR down-regulation and lower Ii up-regulation functions compared to chronic Nef clones. Taken together, our results support enhanced Nef-mediated HLA class II immune evasion activities in acute/early compared to chronic infection, highlighting the potential importance of these functions following transmission. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Molecular Dynamics Simulation Study of Skin Lipids: Effects of the Molar Ratio of Individual Components over a Wide Temperature Range.

    Science.gov (United States)

    Gupta, Rakesh; Rai, Beena

    2015-09-03

    Atomistic molecular dynamics (MD) simulations were employed to systematically investigate the effects of the molar ratio of the individual components cholesterol (CHOL), free fatty acid (FFA), and ceramides (CER) on the properties of the skin lipid bilayer over a wide temperature range (300-400 K). Several independent simulations were performed for bilayers comprised of only CER, CHOL, or FFA molecules as well as those made up of a mixture of CER:CHOL:FFA molecules in different molar ratios. It was found that CHOL increases the stability of the bilayer, since the mixed (CER:CHOL:FFA) 1:1:0, 1:1:1, and 2:2:1 bilayers remained stable until 400 K while the pure ceramide bilayer disintegrated around ∼390 K. It was also observed that CHOL reduces the volume spanned by ceramide molecules, thereby leading to a higher area per CER and FFA molecule in the mixed bilayer system. The CHOL molecule provided more rigidity to the mixed bilayer and led to a more ordered phase at elevated temperatures. The CHOL molecule provided fluidity to the bilayer below the phase transition temperature of CER and kept the bilayer rigid above the phase transition temperature. The FFA interdigitizes with CER molecules and increases the thickness of the bilayer, while rigid CHOL decreases the bilayer thickness. The presence of CHOL increases the compressibility of the bilayer which is responsible for the high barrier function of skin. The CER molecule forms inter- and intramolecular hydrogen bonds, while CHOL only forms intermolecular hydrogen bonds.

  12. Relation of short-range and long-range lithium ion dynamics in glass-ceramics: Insights from 7Li NMR field-cycling and field-gradient studies

    Science.gov (United States)

    Haaks, Michael; Martin, Steve W.; Vogel, Michael

    2017-09-01

    We use various 7Li NMR methods to investigate lithium ion dynamics in 70Li 2S-30 P 2S5 glass and glass-ceramic obtained from this glass after heat treatment. We employ 7Li spin-lattice relaxometry, including field-cycling measurements, and line-shape analysis to investigate short-range ion jumps as well as 7Li field-gradient approaches to characterize long-range ion diffusion. The results show that ceramization substantially enhances the lithium ion mobility on all length scales. For the 70Li 2S-30 P 2S5 glass-ceramic, no evidence is found that bimodal dynamics result from different ion mobilities in glassy and crystalline regions of this sample. Rather, 7Li field-cycling relaxometry shows that dynamic susceptibilities in broad frequency and temperature ranges can be described by thermally activated jumps governed by a Gaussian distribution of activation energies g (Ea) with temperature-independent mean value Em=0.43 eV and standard deviation σ =0.07 eV . Moreover, use of this distribution allows us to rationalize 7Li line-shape results for the local ion jumps. In addition, this information about short-range ion dynamics further explains 7Li field-gradient results for long-range ion diffusion. In particular, we quantitatively show that, consistent with our experimental results, the temperature dependence of the self-diffusion coefficient D is not described by the mean activation energy Em of the local ion jumps, but by a significantly smaller apparent value whenever the distribution of correlation times G (logτ ) of the jump motion derives from an invariant distribution of activation energies and, hence, continuously broadens upon cooling. This effect occurs because the harmonic mean, which determines the results of diffusivity or also conductivity studies, continuously separates from the peak position of G (logτ ) when the width of this distribution increases.

  13. Signature of biased range in the non-dynamical Chern-Simons modified gravity and its measurements with satellite-satellite tracking missions: theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Li-E [Chang' an University, Department of Geophysics, College of Geology Engineering and Geomatics, Xi' an (China); Xu, Peng [Chinese Academy of Sciences, Academy of Mathematics and Systems Science, Beijing (China)

    2015-08-15

    Having great accuracy in the range and range rate measurements, the GRACE mission and the planed GRACE follow on mission can in principle be employed to place strong constraints on certain relativistic gravitational theories. In this paper, we work out the range observable of the non-dynamical Chern-Simons modified gravity for the satellite-to-satellite tracking (SST) measurements. We find out that a characteristic time accumulating range signal appears in non-dynamical Chern-Simons gravity, which has no analogue found in the standard parity-preserving metric theories of gravity. The magnitude of this Chern-Simons range signal will reach a few times of χ cm for each free flight of these SST missions, here χ is the dimensionless post-Newtonian parameter of the non-dynamical Chern-Simons theory. Therefore, with the 12 years data of the GRACE mission, one expects that the mass scale M{sub CS} = (4ℎc)/(χa) of the non-dynamical Chern-Simons gravity could be constrained to be larger than 1.9 x 10.9 eV. For the GRACE FO mission that scheduled to be launched in 2017, the much stronger bound that M{sub CS} ≥ 5 x 10{sup -7} eV is expected. (orig.)

  14. Signature of biased range in the non-dynamical Chern-Simons modified gravity and its measurements with satellite-satellite tracking missions: theoretical studies

    International Nuclear Information System (INIS)

    Qiang, Li-E; Xu, Peng

    2015-01-01

    Having great accuracy in the range and range rate measurements, the GRACE mission and the planed GRACE follow on mission can in principle be employed to place strong constraints on certain relativistic gravitational theories. In this paper, we work out the range observable of the non-dynamical Chern-Simons modified gravity for the satellite-to-satellite tracking (SST) measurements. We find out that a characteristic time accumulating range signal appears in non-dynamical Chern-Simons gravity, which has no analogue found in the standard parity-preserving metric theories of gravity. The magnitude of this Chern-Simons range signal will reach a few times of χ cm for each free flight of these SST missions, here χ is the dimensionless post-Newtonian parameter of the non-dynamical Chern-Simons theory. Therefore, with the 12 years data of the GRACE mission, one expects that the mass scale M CS = (4ℎc)/(χa) of the non-dynamical Chern-Simons gravity could be constrained to be larger than 1.9 x 10.9 eV. For the GRACE FO mission that scheduled to be launched in 2017, the much stronger bound that M CS ≥ 5 x 10 -7 eV is expected. (orig.)

  15. Signature of biased range in the non-dynamical Chern-Simons modified gravity and its measurements with satellite-satellite tracking missions: theoretical studies

    Science.gov (United States)

    Qiang, Li-E.; Xu, Peng

    2015-08-01

    Having great accuracy in the range and range rate measurements, the GRACE mission and the planed GRACE follow on mission can in principle be employed to place strong constraints on certain relativistic gravitational theories. In this paper, we work out the range observable of the non-dynamical Chern-Simons modified gravity for the satellite-to-satellite tracking (SST) measurements. We find out that a characteristic time accumulating range signal appears in non-dynamical Chern-Simons gravity, which has no analogue found in the standard parity-preserving metric theories of gravity. The magnitude of this Chern-Simons range signal will reach a few times of cm for each free flight of these SST missions, here is the dimensionless post-Newtonian parameter of the non-dynamical Chern-Simons theory. Therefore, with the 12 years data of the GRACE mission, one expects that the mass scale of the non-dynamical Chern-Simons gravity could be constrained to be larger than eV. For the GRACE FO mission that scheduled to be launched in 2017, the much stronger bound that eV is expected.

  16. A low-power tool for measuring acceleration, pressure, and temperature (APT) with wide dynamic range and bandwidth

    Science.gov (United States)

    Heesemann, Martin; Davis, Earl E.; Paros, Jerome; Johnson, Greg; Meldrum, Robert; Scherwath, Martin; Mihaly, Steven

    2017-04-01

    We present a new tool that facilitates the study of inter-related geodetic, geodynamic, seismic, and oceanographic phenomena. It incorporates a temperature compensated tri-axial accelerometer developed by Quartz Seismic Sensors, Inc., a pressure sensor built by Paroscientific Inc., and a low-power, high-precision frequency counter developed by Bennest Enterprises Ltd. and built by RBR, Ltd. The sensors are housed in a 7 cm o.d. titanium pressure case designed for use to full ocean depths (withstands more than 20 km of water pressure). Sampling intervals are programmable from 0.08 s to 1 hr; standard memory can store up to 130 million samples; total power consumption is roughly 115 mW when operating continuously and proportionately lower when operating intermittently (e.g., 2 mW average at 1 sample per min). Serial and USB communications protocols allow a variety of autonomous and cable-connection options. Measurement precision of the order of 10-8 of full scale (e.g., pressure equivalent to 4000 m water depth, acceleration = +/- 3 g) allows observations of pressure and acceleration variations of 0.4 Pa and 0.3 μm s-2. Long-term variations in vertical acceleration are sensitive to displacement through the gravity gradient down to a level of roughly 2 cm, and variations in horizontal acceleration are sensitive to tilt down to a level of 0.03 μrad. With the large dynamic ranges, high sensitivities and broad bandwidth (6 Hz to DC), ground motion associated with microseisms, strong and weak seismic ground motion, tidal loading, and slow and rapid geodynamic deformation - all normally studied using disparate instruments - can be observed with a single tool. Installation in the marine environment is accomplished by pushing the tool roughly 1 m vertically below the seafloor with a submersible or remotely operated vehicle, with no profile remaining above the seafloor to cause current-induced noise. The weight of the tool is designed to match the sediment it displaces to

  17. Temperature drives abundance fluctuations, but spatial dynamics is constrained by landscape configuration: Implications for climate-driven range shift in a butterfly.

    Science.gov (United States)

    Fourcade, Yoan; Ranius, Thomas; Öckinger, Erik

    2017-10-01

    Prediction of species distributions in an altered climate requires knowledge on how global- and local-scale factors interact to limit their current distributions. Such knowledge can be gained through studies of spatial population dynamics at climatic range margins. Here, using a butterfly (Pyrgus armoricanus) as model species, we first predicted based on species distribution modelling that its climatically suitable habitats currently extend north of its realized range. Projecting the model into scenarios of future climate, we showed that the distribution of climatically suitable habitats may shift northward by an additional 400 km in the future. Second, we used a 13-year monitoring dataset including the majority of all habitat patches at the species northern range margin to assess the synergetic impact of temperature fluctuations and spatial distribution of habitat, microclimatic conditions and habitat quality, on abundance and colonization-extinction dynamics. The fluctuation in abundance between years was almost entirely determined by the variation in temperature during the species larval development. In contrast, colonization and extinction dynamics were better explained by patch area, between-patch connectivity and host plant density. This suggests that the response of the species to future climate change may be limited by future land use and how its host plants respond to climate change. It is, thus, probable that dispersal limitation will prevent P. armoricanus from reaching its potential future distribution. We argue that models of range dynamics should consider the factors influencing metapopulation dynamics, especially at the range edges, and not only broad-scale climate. It includes factors acting at the scale of habitat patches such as habitat quality and microclimate and landscape-scale factors such as the spatial configuration of potentially suitable patches. Knowledge of population dynamics under various environmental conditions, and the

  18. Coupled Static and Dynamic Buckling Modelling of Thin-Walled Structures in Elastic Range Review of Selected Problems

    Directory of Open Access Journals (Sweden)

    Kołakowski Zbigniew

    2016-06-01

    Full Text Available A review of papers that investigate the static and dynamic coupled buckling and post-buckling behaviour of thin-walled structures is carried out. The problem of static coupled buckling is sufficiently well-recognized. The analysis of dynamic interactive buckling is limited in practice to columns, single plates and shells. The applications of finite element method (FEM or/and analytical-numerical method (ANM to solve interaction buckling problems are on-going. In Poland, the team of scientists from the Department of Strength of Materials, Lodz University of Technology and co-workers developed the analytical-numerical method. This method allows to determine static buckling stresses, natural frequencies, coefficients of the equation describing the post-buckling equilibrium path and dynamic response of the plate structure subjected to compression load and/or bending moment. Using the dynamic buckling criteria, it is possible to determine the dynamic critical load. They presented a lot of interesting results for problems of the static and dynamic coupled buckling of thin-walled plate structures with complex shapes of cross-sections, including an interaction of component plates. The most important advantage of presented analytical-numerical method is that it enables to describe all buckling modes and the post-buckling behaviours of thin-walled columns made of different materials. Thin isotropic, orthotropic or laminate structures were considered.

  19. Improvement of input power dynamic range for 20 Gbit/s optical WDM switch nodes using an integrated Michelson wavelength converter

    DEFF Research Database (Denmark)

    Danielsen, Søren Lykke; Hansen, Peter Bukhave; Jørgensen, Carsten

    1997-01-01

    be improved compared to switch blocks without IWCs. This is especially important at high bit rates where the cascadability of the SOA gates decreases. Here, more than 15 dB improvement of the input power dynamic range is achieved at 20 Gbit/s using a high-speed Michelson interferometer wavelength converter...

  20. Biomechanical effect of interspinous dynamic stabilization adjacent to single-level fusion on range of motion of the transition segment and the adjacent segment.

    Science.gov (United States)

    Kong, Chao; Lu, Shibao; Hai, Yong; Zang, Lei

    2015-05-01

    Despite numerous biomechanical studies have been carried out on dynamic stabilizers, there is very little information on their hybrid application, especially when combined interspinous dynamic stabilization with single-level fusion. The aim of this study is to assess the biomechanical effect of interspinous dynamic stabilization adjacent to single-level fusion on range of motion of the transition segment and the adjacent segment. Six fresh lumbosacral spines (L2-S1) were tested in the following sequence: 1) intact (Construct A); 2) fusion in L5/S1 and intact in L4/5 (Construct B); 3) fusion in L5/S1 and unstable state in L4/5 (Construct C); 4) fusion in L5/S1 and Coflex in L4/5 (Construct D). Range of motion (at L3/4 and L4/5) was recorded and calculated. Range of motion in L3/4 in the four constructs showed no difference under all motion states. Under flexion/extension, the range of motion of L4/5 in Construct B and Construct C increased, while the range of motion of L4/5 in Construct D decreased compared with Construct A. Compared with Construct D, the range of motion of L4/5 in Constructs B and C showed a significant increase. Under lateral bending and axial rotation, Construct A showed similar range of motion of L3/4 compared with other constructs. Fusion combined with Coflex is able to stabilize the transition segment and restrict flexion and extension in that segment, while having no significant effect on the range of motion of the adjacent segment or the range of motion of the transition segment under lateral bending and axial rotation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Snow cover dynamics in the Catalan Pyrenees range using remote sensing data from 2002 to 2008 period

    Science.gov (United States)

    Cea, C.; Cristóbal, J.; Pons, X.

    2009-04-01

    Snow cover dynamics in the Catalan Pyrenees range using remote sensing data from 2002 to 2008 period. C. Cea (1), J. Cristóbal (1), X. Pons (1, 2) (1) Department of Geography. Autonomous University of Barcelona. Cerdanyola del Vallès, 08193. Cristina.Cea@uab.cat, (2) Center for Ecological Research and Forestry Applications (CREAF) Cerdanyola del Vallès, 08193. Water resources and its management are essential in many alpine mountainous areas. Snow cover monitoring in the Mediterranean zone requires obtaining accurate snow cartography to estimate the volume of water derived from snow melting and species distribution modelling. Snow data is usually obtained by field campaigns, but to obtain a spatial and temporal cover of enough detail and quality it is necessary collect an important number of data. However, when a continuous surface is needed, Remote Sensing could provide better snow cover estimation due to its spatial and temporal resolution. The aim of this study is to map snow cover and analyse its spatial and temporal dynamics using medium and coarse remote sensing data at a regional scale over an heterogeneous area, the Catalan Pyrenees (NE of the Iberian Peninsula). The seasonal snow cover period is from October to June. In this period, regular snowfalls usually take place from December to April, although during the rest of the period, punctual but important episodes of snowfalls are frequent. To perform this analysis, a set of 96 Landsat images (36 Landsat-5 TM and 60 Landsat-7 ETM+) of path 197 and 198 and rows 31 and 32 from January 2002 to April 2007, and 90 Terra-MODIS images from October 2007 to July 2008, with a different percentage of cloudiness, have been chosen. The computation of the Landsat-5 TM and Landsat-7 ETM+ data used in snow cover mapping has been carried out by means of the following methodologies. Images have been geometrically corrected by means of techniques based on first order polynomials taking into account the effect of the relief

  2. Stress wave velocity and dynamic modulus of elasticity of yellow-poplar ranging from 100 to 10 percent moisture content

    Science.gov (United States)

    Jody D. Gray; Shawn T. Grushecky; James P. Armstrong

    2008-01-01

    Moisture content has a significant impact on mechanical properties of wood. In recent years, stress wave velocity has been used as an in situ and non-destructive method for determining the stiffness of wooden elements. The objective of this study was to determine what effect moisture content has on stress wave velocity and dynamic modulus of elasticity. Results...

  3. Prospects in the orbital and rotational dynamics of the Moon with the advent of sub-centimeter lunar laser ranging

    OpenAIRE

    Kopeikin, S. M.; Pavlis, E.; Pavlis, D.; Brumberg, V. A.; Escapa, A.; Getino, J.; Gusev, A.; Mueller, J.; Ni, W. -T.; Petrova, N.

    2007-01-01

    Lunar Laser Ranging (LLR) measurements are crucial for advanced exploration of the laws of fundamental gravitational physics and geophysics. Current LLR technology allows us to measure distances to the Moon with a precision approaching 1 millimeter. As NASA pursues the vision of taking humans back to the Moon, new, more precise laser ranging applications will be demanded, including continuous tracking from more sites on Earth, placing new CCR arrays on the Moon, and possibly installing other ...

  4. DFTBaby: A software package for non-adiabatic molecular dynamics simulations based on long-range corrected tight-binding TD-DFT(B)

    Science.gov (United States)

    Humeniuk, Alexander; Mitrić, Roland

    2017-12-01

    A software package, called DFTBaby, is published, which provides the electronic structure needed for running non-adiabatic molecular dynamics simulations at the level of tight-binding DFT. A long-range correction is incorporated to avoid spurious charge transfer states. Excited state energies, their analytic gradients and scalar non-adiabatic couplings are computed using tight-binding TD-DFT. These quantities are fed into a molecular dynamics code, which integrates Newton's equations of motion for the nuclei together with the electronic Schrödinger equation. Non-adiabatic effects are included by surface hopping. As an example, the program is applied to the optimization of excited states and non-adiabatic dynamics of polyfluorene. The python and Fortran source code is available at http://www.dftbaby.chemie.uni-wuerzburg.de.

  5. Static and Dynamic Accuracy of an Innovative Miniaturized Wearable Platform for Short Range Distance Measurements for Human Movement Applications.

    Science.gov (United States)

    Bertuletti, Stefano; Cereatti, Andrea; Comotti, Daniele; Caldara, Michele; Della Croce, Ugo

    2017-06-24

    Magneto-inertial measurement units (MIMU) are a suitable solution to assess human motor performance both indoors and outdoors. However, relevant quantities such as step width and base of support, which play an important role in gait stability, cannot be directly measured using MIMU alone. To overcome this limitation, we developed a wearable platform specifically designed for human movement analysis applications, which integrates a MIMU and an Infrared Time-of-Flight proximity sensor (IR-ToF), allowing for the estimate of inter-object distance. We proposed a thorough testing protocol for evaluating the IR-ToF sensor performances under experimental conditions resembling those encountered during gait. In particular, we tested the sensor performance for different (i) target colors; (ii) sensor-target distances (up to 200 mm) and (iii) sensor-target angles of incidence (AoI) (up to 60 ∘ ). Both static and dynamic conditions were analyzed. A pendulum, simulating the oscillation of a human leg, was used to generate highly repeatable oscillations with a maximum angular velocity of 6 rad/s. Results showed that the IR-ToF proximity sensor was not sensitive to variations of both distance and target color (except for black). Conversely, a relationship between error magnitude and AoI values was found. For AoI equal to 0 ∘ , the IR-ToF sensor performed equally well both in static and dynamic acquisitions with a distance mean absolute error <1.5 mm. Errors increased up to 3.6 mm (static) and 11.9 mm (dynamic) for AoI equal to ± 30 ∘ , and up to 7.8 mm (static) and 25.6 mm (dynamic) for AoI equal to ± 60 ∘ . In addition, the wearable platform was used during a preliminary experiment for the estimation of the inter-foot distance on a single healthy subject while walking. In conclusion, the combination of magneto-inertial unit and IR-ToF technology represents a valuable alternative solution in terms of accuracy, sampling frequency, dimension and power consumption, compared

  6. Static and Dynamic Accuracy of an Innovative Miniaturized Wearable Platform for Short Range Distance Measurements for Human Movement Applications

    Directory of Open Access Journals (Sweden)

    Stefano Bertuletti

    2017-06-01

    Full Text Available Magneto-inertial measurement units (MIMU are a suitable solution to assess human motor performance both indoors and outdoors. However, relevant quantities such as step width and base of support, which play an important role in gait stability, cannot be directly measured using MIMU alone. To overcome this limitation, we developed a wearable platform specifically designed for human movement analysis applications, which integrates a MIMU and an Infrared Time-of-Flight proximity sensor (IR-ToF, allowing for the estimate of inter-object distance. We proposed a thorough testing protocol for evaluating the IR-ToF sensor performances under experimental conditions resembling those encountered during gait. In particular, we tested the sensor performance for different (i target colors; (ii sensor-target distances (up to 200 mm and (iii sensor-target angles of incidence (AoI (up to 60 ∘ . Both static and dynamic conditions were analyzed. A pendulum, simulating the oscillation of a human leg, was used to generate highly repeatable oscillations with a maximum angular velocity of 6 rad/s. Results showed that the IR-ToF proximity sensor was not sensitive to variations of both distance and target color (except for black. Conversely, a relationship between error magnitude and AoI values was found. For AoI equal to 0 ∘ , the IR-ToF sensor performed equally well both in static and dynamic acquisitions with a distance mean absolute error <1.5 mm. Errors increased up to 3.6 mm (static and 11.9 mm (dynamic for AoI equal to ± 30 ∘ , and up to 7.8 mm (static and 25.6 mm (dynamic for AoI equal to ± 60 ∘ . In addition, the wearable platform was used during a preliminary experiment for the estimation of the inter-foot distance on a single healthy subject while walking. In conclusion, the combination of magneto-inertial unit and IR-ToF technology represents a valuable alternative solution in terms of accuracy, sampling frequency, dimension and power consumption

  7. Calibration of high-dynamic-range, finite-resolution x-ray pulse-height spectrometers for extracting electron energy distribution data from the PFRC-2 device

    Science.gov (United States)

    Swanson, C.; Jandovitz, P.; Cohen, S. A.

    2017-10-01

    Knowledge of the full x-ray energy distribution function (XEDF) emitted from a plasma over a large dynamic range of energies can yield valuable insights about the electron energy distribution function (EEDF) of that plasma and the dynamic processes that create them. X-ray pulse height detectors such as Amptek's X-123 Fast SDD with Silicon Nitride window can detect x-rays in the range of 200eV to 100s of keV. However, extracting EEDF from this measurement requires precise knowledge of the detector's response function. This response function, including the energy scale calibration, the window transmission function, and the resolution function, can be measured directly. We describe measurements of this function from x-rays from a mono-energetic electron beam in a purpose-built gas-target x-ray tube. Large-Z effects such as line radiation, nuclear charge screening, and polarizational Bremsstrahlung are discussed.

  8. High-input dynamic range and selectivity stimulated Brillouin scattering-based microwave photonic filter utilizing a dual-stage scheme.

    Science.gov (United States)

    Zhang, Ke; Zhong, Yibo; Ke, Changjian; Liu, Deming

    2017-09-01

    A high-input dynamic range and selectivity stimulated Brillouin scattering (SBS)-based microwave photonic filter (MPF) is proposed and experimentally demonstrated. By utilizing a pump-splitting dual-stage scheme to mitigate the gain saturation, an input dynamic range of >40  dB and a selectivity of >49  dB are achieved simultaneously for the first time, to the best of our knowledge. The bandwidth is reconfigurable from 50 MHz to 200 MHz by tailoring the Brillouin pump precisely. During the bandwidth turning, the passband ripple is maintained <1.3  dB, and the 20-dB shape factor is 1.2 for the 200-MHz case. The superior performance makes the proposed SBS-MPF one of the best candidates for microwave photonics applications.

  9. Charge-leveling and proper treatment of long-range electrostatics in all-atom molecular dynamics at constant pH.

    Science.gov (United States)

    Wallace, Jason A; Shen, Jana K

    2012-11-14

    Recent development of constant pH molecular dynamics (CpHMD) methods has offered promise for adding pH-stat in molecular dynamics simulations. However, until now the working pH molecular dynamics (pHMD) implementations are dependent in part or whole on implicit-solvent models. Here we show that proper treatment of long-range electrostatics and maintaining charge neutrality of the system are critical for extending the continuous pHMD framework to the all-atom representation. The former is achieved here by adding forces to titration coordinates due to long-range electrostatics based on the generalized reaction field method, while the latter is made possible by a charge-leveling technique that couples proton titration with simultaneous ionization or neutralization of a co-ion in solution. We test the new method using the pH-replica-exchange CpHMD simulations of a series of aliphatic dicarboxylic acids with varying carbon chain length. The average absolute deviation from the experimental pK(a) values is merely 0.18 units. The results show that accounting for the forces due to extended electrostatics removes the large random noise in propagating titration coordinates, while maintaining charge neutrality of the system improves the accuracy in the calculated electrostatic interaction between ionizable sites. Thus, we believe that the way is paved for realizing pH-controlled all-atom molecular dynamics in the near future.

  10. Sub-Zero Temperature Chromatography for Reduced Back-Exchange and Improved Dynamic Range in Amide Hydrogen Deuterium Exchange Mass Spectrometry

    OpenAIRE

    Venable, John D.; Okach, Linda; Agarwalla, Sanjay; Brock, Ansgar

    2012-01-01

    Amide hydrogen/deuterium exchange is a commonly used technique for studying the dynamics of proteins and their interactions with other proteins or ligands. When coupled with liquid chromatography and mass spectrometry, hydrogen/deuterium exchange provides several unique advantages over other structural characterization techniques including very high sensitivity, the ability to analyze proteins in complex environments, and a large mass range. A fundamental limitation of the technique arises fr...

  11. Toward a single-chip TECless/NUCless InGaAs SWIR camera with 120-dB intrinsic operation dynamic range

    Science.gov (United States)

    Ni, Y.; Arion, B.; Zhu, Y. M.; Potet, P.; Huet, Odile; Reverchon, Jean Luc; Truffer, Jean Patrick; Robo, Jean Alexandre; Costard, Eric

    2011-06-01

    This paper describes a single-chip InGaAs SWIR camera with more than 120dB instant operational dynamic range with an innovative CMOS ROIC technology, so called MAGIC, invented and patented by New Imaging Technologies. A 320x256- pixel InGaAs 25μm pitch photodiode array, designed and fabricated by III-Vlab/Thales Research & Technology(TRT), has been hybridized on this new generation CMOS ROIC. With NIT's MAGIC technology, the sensor's output follows a precise logarithmic law in function of incoming photon flux and gives instant operational dynamic range (DR) better than 120 dB. The ROIC incorporates the entire video signal processing function including a CCIR TV encoder, so a complete SWIR InGaAs camera with standard video output has been realized on a single 30x30 mm2 PCB board with ¼ W power consumption. Neither TEC nor NUC is needed from room temperature operation. The camera can be switched on and off instantly, ideal for all the portable battery operated SWIR band observation applications. The measured RMS noise and FPN noise on the prototype sensor in dark conditions are 0.4 mV and 0.27 mV respectively. The signal excursion from pixel is about 300mV over the 120 dB dynamic range. The FPN remains almost constant over the whole operation dynamic range. The NEI has been measured to be 3,71E+09 ph/s/cm2 with 92 equivalent noise photons at 25Hz frame rate, better than the same architecture of InGaAs photodiode array hybridized on an Indigo ROIC ISC9809 with a pitch of 30 μm for which a readout noise of 120 electrons is observed.

  12. The presence of nuclear cactus in the early Drosophila embryo may extend the dynamic range of the dorsal gradient.

    Directory of Open Access Journals (Sweden)

    Michael D O'Connell

    2015-04-01

    Full Text Available In a developing embryo, the spatial distribution of a signaling molecule, or a morphogen gradient, has been hypothesized to carry positional information to pattern tissues. Recent measurements of morphogen distribution have allowed us to subject this hypothesis to rigorous physical testing. In the early Drosophila embryo, measurements of the morphogen Dorsal, which is a transcription factor responsible for initiating the earliest zygotic patterns along the dorsal-ventral axis, have revealed a gradient that is too narrow to pattern the entire axis. In this study, we use a mathematical model of Dorsal dynamics, fit to experimental data, to determine the ability of the Dorsal gradient to regulate gene expression across the entire dorsal-ventral axis. We found that two assumptions are required for the model to match experimental data in both Dorsal distribution and gene expression patterns. First, we assume that Cactus, an inhibitor that binds to Dorsal and prevents it from entering the nuclei, must itself be present in the nuclei. And second, we assume that fluorescence measurements of Dorsal reflect both free Dorsal and Cactus-bound Dorsal. Our model explains the dynamic behavior of the Dorsal gradient at lateral and dorsal positions of the embryo, the ability of Dorsal to regulate gene expression across the entire dorsal-ventral axis, and the robustness of gene expression to stochastic effects. Our results have a general implication for interpreting fluorescence-based measurements of signaling molecules.

  13. Evolutionary dynamics of a rapidly receding southern range boundary in the threatened California red-legged frog (Rana draytonii)

    Science.gov (United States)

    Richmond, Jonathan Q.; Barr, Kelly R.; Backlin, Adam R.; Vandergast, Amy G.; Fisher, Robert N.

    2013-01-01

    Populations forming the edge of a species range are often imperiled by isolation and low genetic diversity, with proximity to human population centers being a major determinant of edge stability in modern landscapes. Since the 1960s, the California red-legged frog (Rana draytonii) has undergone extensive declines in heavily urbanized southern California, where the range edge has rapidly contracted northward while shifting its cardinal orientation to an east-west trending axis. We studied the genetic structure and diversity of these frontline populations, tested for signatures of contemporary disturbance, specifically fire, and attempted to disentangle these signals from demographic events extending deeper into the past. Consistent with the genetic expectations of the ‘abundant-center’ model, we found that diversity, admixture, and opportunity for random mating increases in populations sampled successively further away from the range boundary. Demographic simulations indicate that bottlenecks in peripheral isolates are associated with processes extending tens to a few hundred generations in the past, despite the demographic collapse of some due to recent fire-flood events. While the effects of recent disturbance have left little genetic imprint on these populations, they likely contribute to an extinction debt that will lead to continued range contraction unless management intervenes to stall or reverse the process.

  14. Second-harmonic-generation-based technique for examining laser diode wavelength dynamics in the mu s to ms range

    DEFF Research Database (Denmark)

    Christensen, Mathias; Hansen, Anders Kragh; Noordegraaf, Danny

    2018-01-01

    Wavelength information is essential for any researcher in optics and photonics, and for this reason, a wide range of devices is available for measuring it. However, the techniques available today are limited either to a resolution of nanometers or a measurement rate of kHz. In this paper, we pres...

  15. Molecular dynamics studies of short to medium range order in Cu{sub 64}Zr{sub 36} metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Sha, Z.D., E-mail: shaz@ihpc.a-star.edu.sg [Institute of High Performance Computing, 1 Fusionopolis Way, Singapore 138632 (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Zhang, Y.W. [Institute of High Performance Computing, 1 Fusionopolis Way, Singapore 138632 (Singapore); Feng, Y.P. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Li, Y. [Department of Materials Science and Engineering, National University of Singapore, Engineering Drive 1, Singapore 117576 (Singapore)

    2011-08-18

    Highlights: > Short- and medium-range orders in Cu{sub 64}Zr{sub 36} metallic glass were investigated. > We employed the concept of core-shell rather than cluster packing. > The basic atomic structure has the characteristics of an icosahedral shell structure. > This finding applies to short- and medium-range orders in the optimum glass former. - Abstract: For metallic glasses, the cluster packing scheme addresses mainly the low solute concentration regime and it breaks down beyond a length scale of a few clusters. In the present work, from the viewpoint of core-shell structure rather than cluster packing, short- and medium-range orders in Cu{sub 64}Zr{sub 36} metallic glass were investigated using the large-scale atomic/molecular massively parallel simulator. In the first three coordination shells, the total number of atoms within the nth coordination shell is 13, 61, and 169. And the number of atoms on the nth coordination shell is 12n{sup 2}. Besides, the basic atomic structure could be obtained from a central icosahedron surrounded by a shell of 12n{sup 2} atoms. From the fourth coordination shell on, the total number of atoms is 307, 561, and 924, respectively, consistent with that in an icosahedral shell structure. Our finding suggests that for the optimum glass former in the Cu-Zr binary system, the basic atomic structures over both short- and medium-range length scales have the characteristics of an icosahedral shell structure.

  16. Intermediate frequency band digitized high dynamic range radiometer system for plasma diagnostics and real-time Tokamak control

    NARCIS (Netherlands)

    Bongers, W. A.; van Beveren, V.; Thoen, D. J.; Nuij, Pjwm; M.R. de Baar,; Donne, A. J. H.; Westerhof, E.; Goede, A. P. H.; Krijger, B.; van den Berg, M. A.; Kantor, M.; M. F. Graswinckel,; Hennen, B.A.; Schüller, F. C.

    2011-01-01

    An intermediate frequency (IF) band digitizing radiometer system in the 100-200 GHz frequency range has been developed for Tokamak diagnostics and control, and other fields of research which require a high flexibility in frequency resolution combined with a large bandwidth and the retrieval of the

  17. Intermediate frequency band digitized high dynamic range radiometer system for plasma diagnostics and real-time Tokamak control

    NARCIS (Netherlands)

    Bongers, WA.; Van Beveren, V.; Thoen, D.J.; Nuij, P.J.W.M.; De Baar, M.R.; Donné, A.J.H.; Westerhof, E.; Goede, A.P.H.; Krijger, B.; Van den Berg, M.A.; Kantor, M.; Graswinckel, M.F.; Hennen, B.A.; Schüller, F.C.

    2011-01-01

    An intermediate frequency (IF) band digitizing radiometer system in the 100–200 GHz frequency range has been developed for Tokamak diagnostics and control, and other fields of research which require a high flexibility in frequency resolution combined with a large bandwidth and the retrieval of the

  18. Short-range magnetic correlations and spin dynamics in the paramagnetic regime of (Mn,Fe)2(P,Si)

    NARCIS (Netherlands)

    Miao, X.F.; Caron, L.; Cedervall, J.; Gubbens, P.C.M.; Dalmas de Réotier, P; Yaouanc, A; Qian, F.; Wildes, A. R.; Luetkens, H.; Amato, A; van Dijk, N.H.; Brück, E.H.

    2016-01-01

    The spatial and temporal correlations of magnetic moments in the paramagnetic regime of (Mn,Fe)2(P,Si) have been investigated by means of polarized neutron diffraction and muon-spin relaxation techniques. Short-range magnetic correlations are present at temperatures far above the ferromagnetic

  19. Development of a primary standard for dynamic pressure based on drop weight method covering a range of 10 MPa-400 MPa

    Science.gov (United States)

    Salminen, J.; Högström, R.; Saxholm, S.; Lakka, A.; Riski, K.; Heinonen, M.

    2018-04-01

    In this paper we present the development of a primary standard for dynamic pressures that is based on the drop weight method. At the moment dynamic pressure transducers are typically calibrated using reference transducers, which are calibrated against static pressure standards. Because dynamic and static characteristics of pressure transducers may significantly differ from each other, it is important that these transducers are calibrated against dynamic pressure standards. In a method developed in VTT Technical Research Centre of Finland Ltd, Centre for Metrology MIKES, a pressure pulse is generated by impact between a dropping weight and a piston of a liquid-filled piston-cylinder assembly. The traceability to SI-units is realized through interferometric measurement of the acceleration of the dropping weight during impact, the effective area of the piston-cylinder assembly and the mass of the weight. Based on experimental validation and an uncertainty evaluation, the developed primary standard provides traceability for peak pressures in the range from 10 MPa to 400 MPa with a few millisecond pulse width and a typical relative expanded uncertainty (k  =  2) of 1.5%. The performance of the primary standard is demonstrated by test calibrations of two dynamic pressure transducers.

  20. Cellular tropism, population dynamics, host range and taxonomic status of an aphid secondary symbiont, SMLS (Sitobion miscanthi L type symbiont.

    Directory of Open Access Journals (Sweden)

    Tong Li

    Full Text Available SMLS (Sitobion miscanthi L type symbiont is a newly reported aphid secondary symbiont. Phylogenetic evidence from molecular markers indicates that SMLS belongs to the Rickettsiaceae and has a sibling relationship with Orientia tsutsugamushi. A comparative analysis of coxA nucleotide sequences further supports recognition of SMLS as a new genus in the Rickettsiaceae. In situ hybridization reveals that SMLS is housed in both sheath cells and secondary bacteriocytes and it is also detected in aphid hemolymph. The population dynamics of SMLS differ from those of Buchnera aphidicola and titer levels of SMLS increase in older aphids. A survey of 13 other aphids reveals that SMLS only occurs in wheat-associated species.

  1. High dynamic range low-noise focal plane readout for VLWIR applications implemented with current mode background subtraction

    Science.gov (United States)

    Yang, Guang; Sun, Chao; Shaw, Timothy; Wrigley, Chris; Peddada, Pavani; Blazejewski, Edward R.; Pain, Bedabrata

    1998-09-01

    Design and operation of a low noise CMOS focal pa;ne readout circuit with ultra-high charge handling capacity is presented. Designed for high-background, VLWIR detector readout, each readout unit cell use an accurate dynamic current memory for automatic subtraction of the dark pedestal in current domain enabling measurement of small signals 85 dB below the dark level. The redout circuit operates with low-power dissipation, high linearity, and is capable of handling pedestal currents up to 300 nA. Measurements indicate an effective charge handling capacity of over 5 X 10(superscript 9) charges/pixel with less than 10(superscript 5) electrons of input referred noise.

  2. Cellular Tropism, Population Dynamics, Host Range and Taxonomic Status of an Aphid Secondary Symbiont, SMLS (Sitobion miscanthi L Type Symbiont)

    Science.gov (United States)

    Li, Tong; Xiao, Jin-Hua; Xu, Zhao-Huan; Murphy, Robert W.; Huang, Da-Wei

    2011-01-01

    SMLS (Sitobion miscanthi L type symbiont) is a newly reported aphid secondary symbiont. Phylogenetic evidence from molecular markers indicates that SMLS belongs to the Rickettsiaceae and has a sibling relationship with Orientia tsutsugamushi. A comparative analysis of coxA nucleotide sequences further supports recognition of SMLS as a new genus in the Rickettsiaceae. In situ hybridization reveals that SMLS is housed in both sheath cells and secondary bacteriocytes and it is also detected in aphid hemolymph. The population dynamics of SMLS differ from those of Buchnera aphidicola and titer levels of SMLS increase in older aphids. A survey of 13 other aphids reveals that SMLS only occurs in wheat-associated species. PMID:21789197

  3. Short-term occupancy and abundance dynamics of the Oregon spotted frog (Rana pretiosa) across its core range

    Science.gov (United States)

    Adams, Michael J.; Pearl, Christopher A.; Mccreary, Brome; Galvan, Stephanie

    2014-01-01

    The Oregon spotted frog (Rana pretiosa) occupies only a fraction of its original range and is listed as Threatened under the Endangered Species Act. We surveyed 93 sites in a rotating frame design (2010–13) in the Klamath and Deschutes Basins, Oregon, which encompass most of the species’ core extant range. Oregon spotted frogs are declining in abundance and probability of site occupancy. We did not find an association between the probability that Oregon spotted frogs disappear from a site (local extinction) and any of the variables hypothesized to affect Oregon spotted frog occupancy. This 4-year study provides baseline data, but the 4-year period was too short to draw firm conclusions. Further study is essential to understand how habitat changes and management practices relate to the status and trends of this species.

  4. Out of the tropics, but how? Fossils, bridge species, and thermal ranges in the dynamics of the marine latitudinal diversity gradient.

    Science.gov (United States)

    Jablonski, David; Belanger, Christina L; Berke, Sarah K; Huang, Shan; Krug, Andrew Z; Roy, Kaustuv; Tomasovych, Adam; Valentine, James W

    2013-06-25

    Latitudinal diversity gradients are underlain by complex combinations of origination, extinction, and shifts in geographic distribution and therefore are best analyzed by integrating paleontological and neontological data. The fossil record of marine bivalves shows, in three successive late Cenozoic time slices, that most clades (operationally here, genera) tend to originate in the tropics and then expand out of the tropics (OTT) to higher latitudes while retaining their tropical presence. This OTT pattern is robust both to assumptions on the preservation potential of taxa and to taxonomic revisions of extant and fossil species. Range expansion of clades may occur via "bridge species," which violate climate-niche conservatism to bridge the tropical-temperate boundary in most OTT genera. Substantial time lags (∼5 Myr) between the origins of tropical clades and their entry into the temperate zone suggest that OTT events are rare on a per-clade basis. Clades with higher diversification rates within the tropics are the most likely to expand OTT and the most likely to produce multiple bridge species, suggesting that high speciation rates promote the OTT dynamic. Although expansion of thermal tolerances is key to the OTT dynamic, most latitudinally widespread species instead achieve their broad ranges by tracking widespread, spatially-uniform temperatures within the tropics (yielding, via the nonlinear relation between temperature and latitude, a pattern opposite to Rapoport's rule). This decoupling of range size and temperature tolerance may also explain the differing roles of species and clade ranges in buffering species from background and mass extinctions.

  5. Effects of sample injection amount and time-of-flight mass spectrometric detection dynamic range on metabolome analysis by high-performance chemical isotope labeling LC-MS.

    Science.gov (United States)

    Zhou, Ruokun; Li, Liang

    2015-04-06

    The effect of sample injection amount on metabolome analysis in a chemical isotope labeling (CIL) liquid chromatography-mass spectrometry (LC-MS) platform was investigated. The performance of time-of-flight (TOF) mass spectrometers with and without a high-dynamic-range (HD) detection system was compared in the analysis of (12)C2/(13)C2-dansyl labeled human urine samples. An average of 1635 ± 21 (n = 3) peak pairs or putative metabolites was detected using the HD-TOF-MS, compared to 1429 ± 37 peak pairs from a conventional or non-HD TOF-MS. In both instruments, signal saturation was observed. However, in the HD-TOF-MS, signal saturation was mainly caused by the ionization process, while in the non-HD TOF-MS, it was caused by the detection process. To extend the MS detection range in the non-HD TOF-MS, an automated switching from using (12)C to (13)C-natural abundance peaks for peak ratio calculation when the (12)C peaks are saturated has been implemented in IsoMS, a software tool for processing CIL LC-MS data. This work illustrates that injecting an optimal sample amount is important to maximize the metabolome coverage while avoiding the sample carryover problem often associated with over-injection. A TOF mass spectrometer with an enhanced detection dynamic range can also significantly increase the number of peak pairs detected. In chemical isotope labeling (CIL) LC-MS, relative metabolite quantification is done by measuring the peak ratio of a (13)C2-/(12)C2-labeled peak pair for a given metabolite present in two comparative samples. The dynamic range of peak ratio measurement does not need to be very large, as only subtle changes of metabolite concentrations are encountered in most metabolomic studies where relative metabolome quantification of different groups of samples is performed. However, the absolute concentrations of different metabolites can be very different, requiring a technique to provide a wide detection dynamic range to allow the detection of as

  6. HIGH DYNAMIC RANGE OBSERVATIONS OF SOLAR CORONAL TRANSIENTS AT LOW RADIO FREQUENCIES WITH A SPECTRO-CORRELATOR

    Energy Technology Data Exchange (ETDEWEB)

    Hariharan, K.; Ramesh, R.; Kathiravan, C.; Rajalingam, M. [Indian Institute of Astrophysics, Bangalore-560034 (India); Abhilash, H. N., E-mail: khariharan@iiap.res.in [Poornaprajna College, Udupi-576101 (India)

    2016-02-15

    A new antenna system with a digital spectro-correlator that provides high temporal, spectral, and amplitude resolutions has been commissioned at the Gauribidanur Observatory near Bangalore in India. Presently, it is used for observations of the solar coronal transients in the scarcely explored frequency range ≈30–15 MHz. The details of the antenna system, the associated receiver setup, and the initial observational results are reported. Some of the observed transients exhibited quasi-periodicity in their time profiles at discrete frequencies. Estimates of the associated magnetic field strength (B) indicate that B ≈ 0.06–1 G at a typical frequency such as 19.5 MHz.

  7. A Long-Range Electric Field Solver for Molecular Dynamics Based on Atomistic-to-Continuum Modeling.

    Science.gov (United States)

    Templeton, Jeremy A; Jones, Reese E; Lee, Jonathan W; Zimmerman, Jonathan A; Wong, Bryan M

    2011-06-14

    Understanding charge transport processes at a molecular level is currently hindered by a lack of appropriate models for incorporating nonperiodic, anisotropic electric fields in molecular dynamics (MD) simulations. In this work, we develop a model for including electric fields in MD using an atomistic-to-continuum framework. This framework provides the mathematical and the algorithmic infrastructure to couple finite element (FE) representations of continuous data with atomic data. Our model represents the electric potential on a FE mesh satisfying a Poisson equation with source terms determined by the distribution of the atomic charges. Boundary conditions can be imposed naturally using the FE description of the potential, which then propagate to each atom through modified forces. The method is verified using simulations where analytical solutions are known or comparisons can be made to existing techniques. In addition, a calculation of a salt water solution in a silicon nanochannel is performed to demonstrate the method in a target scientific application in which ions are attracted to charged surfaces in the presence of electric fields and interfering media.

  8. Radiation-induced alterations of the proliferation dynamics of human skin fibroblasts after repeated irradiation in the subtherapeutic dose range

    International Nuclear Information System (INIS)

    Bumann, J.; Santo-Hoeltje, L.; Loeffler, H.; Bamberg, M.; Rodemann, H.P.

    1995-01-01

    The aim of this study was to determine the effect of single and multiple irradiations on the differentiation and proliferation pattern of the stem cell system of human fibroblasts. The pattern of differentiation of fibroblast cultures was analyzed by morphological criteria using colony forming assays. Proliferation rates were assessed by cell counting and measuring the incorporation of BrdU. Ionizing radiation both in low and high dose ranges exerts differential effects on the cellular processes of differentiation and proliferation in human fibroblasts. Single irradiations of fibroblasts in the dose range of 1 to 8 Gy induced terminal differentiation into postmitotic fibrocytes at high percentage level. Irradiation of longterm cultures of fibroblasts with repeated doses of 0.2, 0.6 and 1.0 Gy revealed that only in cultures, which were irradiated repeatedly (x10) with 0.6 and 1.0 Gy a marked reduction of the proliferation capacity was apparent. Inhibition of proliferation by repeated irradiations with cumulative doses up to 10 Gy was not more pronounced as compared to single irradiations. 1. These results of radiation-induced changes in the proliferation and differentiation pattern of cells may be a basis for the understanding of the cellular processes leading to radiation-induced fibrosis and tissue aging. 2. Multiple irradiations with single doses up to 1 Gy and cumulative doses up to 10 Gy did not change the radiosensitivity of fibroblast cultures regarding effects on cell proliferation. (orig.) [de

  9. On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1–20 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Fannin, P.C. [Department of Electronic and Electrical Engineering, Trinity College, University of Dublin, Dublin 2 (Ireland); Vekas, L. [Center for Fundamental Technical Research, Romanian Academy-Timisoara Branch, Timisoara (Romania); Marin, C.N., E-mail: catalin.marin@e-uvt.ro [West University of Timisoara, Faculty of Physics, V. Parvan Blv., no. 4, 300223 Timisoara (Romania); Malaescu, I. [West University of Timisoara, Faculty of Physics, V. Parvan Blv., no. 4, 300223 Timisoara (Romania)

    2017-02-01

    Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ′(ω, Η)−iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1–20 GHz and polarising fields 0–168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4–6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz. - Highlights: • Complex magnetic susceptibility measurements in the frequency range 0.1–20 GHz. • Determination of the dynamic properties of a transformer oil based ferrofluid. • Wideband attenuator ( Absorber) in the frequency range 2.4–6.3 GHz.

  10. Effects of group dynamics and diet on the ranging patterns of a western gorilla group (Gorilla gorilla gorilla) at Bai Hokou, Central African Republic.

    Science.gov (United States)

    Cipolletta, Chloé

    2004-10-01

    This study describes how group dynamics and diet have influenced the ranging patterns of a western gorilla group at Bai Hokou, Central African Republic. The results are compared with those from an earlier study [Cipolletta, International Journal of Primatology, 2003], when the same group was larger and undergoing the process of habituation to humans. Data were obtained from maps of the gorillas' travel routes, direct observations, and analysis of fecal samples. Through the years, the group has experienced a decrease in size, from eight to three individuals, with periods of membership fluctuation. The male's search for new mates resulted in a larger home range than was recorded when the group consisted of more individuals. Moreover, despite an average group size of three throughout this study, the monthly range and mean daily path length (DPL) were also larger when the group was acquiring/losing members in new areas, than when no new members joined or left the group. Fruit was consumed year-round, although more heavily so during wet months. The influence of fruit consumption on the ranging patterns was concealed initially by the effect of habituation [Cipolletta, International Journal of Primatology, 2003], and later (at least partially) by the male's search for new mates. In the last 14 months of the study, when the group numbered only three individuals and was ranging in a restricted area, the average DPL, but not the monthly range, increased when the gorillas were consuming more fruit.

  11. Quantitative, simultaneous, and collinear eye-tracked, high dynamic range optical coherence tomography at 850 and 1060 nm

    Science.gov (United States)

    Mooser, Matthias; Burri, Christian; Stoller, Markus; Luggen, David; Peyer, Michael; Arnold, Patrik; Meier, Christoph; Považay, Boris

    2017-07-01

    Ocular optical coherence tomography at the wavelengths ranges of 850 and 1060 nm have been integrated with a confocal scanning laser ophthalmoscope eye-tracker as a clinical commercial-class system. Collinear optics enables an exact overlap of the different channels to produce precisely overlapping depth-scans for evaluating the similarities and differences between the wavelengths to extract additional physiologic information. A reliable segmentation algorithm utilizing Graphcuts has been implemented and applied to automatically extract retinal and choroidal shape in cross-sections and volumes. The device has been tested in normals and pathologies including a cross-sectional and longitudinal study of myopia progress and control with a duplicate instrument in Asian children.

  12. Investigating local and long-range neuronal network dynamics by simultaneous optogenetics, reverse microdialysis and silicon probe recordings in vivo.

    Science.gov (United States)

    Taylor, Hannah; Schmiedt, Joscha T; Carçak, Nihan; Onat, Filiz; Di Giovanni, Giuseppe; Lambert, Régis; Leresche, Nathalie; Crunelli, Vincenzo; David, Francois

    2014-09-30

    The advent of optogenetics has given neuroscientists the opportunity to excite or inhibit neuronal population activity with high temporal resolution and cellular selectivity. Thus, when combined with recordings of neuronal ensemble activity in freely moving animals optogenetics can provide an unprecedented snapshot of the contribution of neuronal assemblies to (patho)physiological conditions in vivo. Still, the combination of optogenetic and silicone probe (or tetrode) recordings does not allow investigation of the role played by voltage- and transmitter-gated channels of the opsin-transfected neurons and/or other adjacent neurons in controlling neuronal activity. We demonstrate that optogenetics and silicone probe recordings can be combined with intracerebral reverse microdialysis for the long-term delivery of neuroactive drugs around the optic fiber and silicone probe. In particular, we show the effect of antagonists of T-type Ca(2+) channels, hyperpolarization-activated cyclic nucleotide-gated channels and metabotropic glutamate receptors on silicone probe-recorded activity of the local opsin-transfected neurons in the ventrobasal thalamus, and demonstrate the changes that the block of these thalamic channels/receptors brings about in the network dynamics of distant somatotopic cortical neuronal ensembles. This is the first demonstration of successfully combining optogenetics and neuronal ensemble recordings with reverse microdialysis. This combination of techniques overcomes some of the disadvantages that are associated with the use of intracerebral injection of a drug-containing solution at the site of laser activation. The combination of reverse microdialysis, silicone probe recordings and optogenetics can unravel the short and long-term effects of specific transmitter- and voltage-gated channels on laser-modulated firing at the site of optogenetic stimulation and the actions that these manipulations exert on distant neuronal populations. Copyright © 2014

  13. Temporal dynamics of epidermal responses of guppies Poecilia reticulata to a sublethal range of waterborne zinc concentrations.

    Science.gov (United States)

    Gheorghiu, C; Marcogliese, D J; Scott, M E

    2009-12-01

    This study assessed the histological changes in the epidermis of guppies Poecilia reticulata induced by waterborne zinc (Zn). Laboratory-reared P. reticulata fry were maintained individually in separate vessels containing artificial water (8 microg l(-1) Zn) to which 0, 15, 30, 60 or 120 microg l(-1) Zn was added. Their epidermal response to Zn was monitored regularly over 4 weeks. Compared with controls, mucus was rapidly released and mucous cell numbers decreased at all concentrations. Thereafter mucous release, epidermal thickness, numbers and size of mucous cells fluctuated at a rate that varied with Zn concentration, but fluctuations declined after day 18. Results clearly highlight the dynamic nature of the epidermal response to sublethal concentrations of waterborne Zn. In general, low concentrations of Zn induced a rapid response with reduced numbers and size of mucous cells and shift in mucin composition, and a subsequent thickening of the epidermis. Epidermal thickness and mucous cell area fluctuated over time but were normal after a month of exposure to low Zn concentrations. The number of mucous cells, however, remained low. Virtually all mucous cells from fish maintained in 15 and 60 microg l(-1) Zn contained acidic mucins throughout the month, whereas fish maintained at 30 microg l(-1) Zn responded by production of neutral mucins during the first 12 days followed by a mixture of neutral and acidic mucins. At 120 microg l(-1) Zn, the most dramatic effects were the gradual but sustained decrease in numbers and area of mucous cells, and the shift to acidic mucins in these cells. Thus, as concentration of Zn increased, the epidermal responses indicated a disturbed host response (dramatic decline in mucous cell numbers, with mixed composition of mucins), which may have been less effective in preventing Zn uptake across the epithelium.

  14. Invading and Expanding: Range Dynamics and Ecological Consequences of the Greater White-Toothed Shrew (Crocidura russula) Invasion in Ireland

    Science.gov (United States)

    McDevitt, Allan D.; Montgomery, W. Ian; Tosh, David G.; Lusby, John; Reid, Neil; White, Thomas A.; McDevitt, C. Damien; O'Halloran, John; Searle, Jeremy B.; Yearsley, Jon M.

    2014-01-01

    Establishing how invasive species impact upon pre-existing species is a fundamental question in ecology and conservation biology. The greater white-toothed shrew (Crocidura russula) is an invasive species in Ireland that was first recorded in 2007 and which, according to initial data, may be limiting the abundance/distribution of the pygmy shrew (Sorex minutus), previously Ireland's only shrew species. Because of these concerns, we undertook an intensive live-trapping survey (and used other data from live-trapping, sightings and bird of prey pellets/nest inspections collected between 2006 and 2013) to model the distribution and expansion of C. russula in Ireland and its impacts on Ireland's small mammal community. The main distribution range of C. russula was found to be approximately 7,600 km2 in 2013, with established outlier populations suggesting that the species is dispersing with human assistance within the island. The species is expanding rapidly for a small mammal, with a radial expansion rate of 5.5 km/yr overall (2008–2013), and independent estimates from live-trapping in 2012–2013 showing rates of 2.4–14.1 km/yr, 0.5–7.1 km/yr and 0–5.6 km/yr depending on the landscape features present. S. minutus is negatively associated with C. russula. S. minutus is completely absent at sites where C. russula is established and is only present at sites at the edge of and beyond the invasion range of C. russula. The speed of this invasion and the homogenous nature of the Irish landscape may mean that S. minutus has not had sufficient time to adapt to the sudden appearance of C. russula. This may mean the continued decline/disappearance of S. minutus as C. russula spreads throughout the island. PMID:24955824

  15. A Computational Fluid Dynamics Study of Transitional Flows in Low-Pressure Turbines under a Wide Range of Operating Conditions

    Science.gov (United States)

    Suzen, Y. B.; Huang, P. G.; Ashpis, D. E.; Volino, R. J.; Corke, T. C.; Thomas, F. O.; Huang, J.; Lake, J. P.; King, P. I.

    2007-01-01

    A transport equation for the intermittency factor is employed to predict the transitional flows in low-pressure turbines. The intermittent behavior of the transitional flows is taken into account and incorporated into computations by modifying the eddy viscosity, mu(sub p) with the intermittency factor, gamma. Turbulent quantities are predicted using Menter's two-equation turbulence model (SST). The intermittency factor is obtained from a transport equation model which can produce both the experimentally observed streamwise variation of intermittency and a realistic profile in the cross stream direction. The model had been previously validated against low-pressure turbine experiments with success. In this paper, the model is applied to predictions of three sets of recent low-pressure turbine experiments on the Pack B blade to further validate its predicting capabilities under various flow conditions. Comparisons of computational results with experimental data are provided. Overall, good agreement between the experimental data and computational results is obtained. The new model has been shown to have the capability of accurately predicting transitional flows under a wide range of low-pressure turbine conditions.

  16. Windthrow Dynamics in Boreal Ontario: A Simulation of the Vulnerability of Several Stand Types across a Range of Wind Speeds

    Directory of Open Access Journals (Sweden)

    Kenneth A. Anyomi

    2017-06-01

    Full Text Available In Boreal North America, management approaches inspired by the variability in natural disturbances are expected to produce more resilient forests. Wind storms are recurrent within Boreal Ontario. The objective of this study was to simulate wind damage for common Boreal forest types for regular as well as extreme wind speeds. The ForestGALES_BC windthrow prediction model was used for these simulations. Input tree-level data were derived from permanent sample plot (PSP data provided by the Ontario Ministry of Natural Resources. PSPs were assigned to one of nine stand types: Balsam fir-, Jack pine-, Black spruce-, and hardwood-dominated stands, and, Jack pine-, spruce-, conifer-, hardwood-, and Red and White pine-mixed species stands. Morphological and biomechanical parameters for the major tree species were obtained from the literature. At 5 m/s, predicted windthrow ranged from 0 to 20%, with damage increasing to 2 to 90% for winds of 20 m/s and to 10 to 100% for winds of 40 m/s. Windthrow varied by forest stand type, with lower vulnerability within hardwoods. This is the first study to provide such broad simulations of windthrow vulnerability data for Boreal North America, and we believe this will benefit policy decisions regarding risk management and forest planning.

  17. The TSH dynamics in upperand low-normal range in patients with primary hypothyroidism: clinical presentation, well-being and quality of life

    Directory of Open Access Journals (Sweden)

    A V Podzolkov

    2010-12-01

    Full Text Available In our study we try to determine whether small changes in thyroxine treatment is effective in patients with symptoms of hypothyroidism but with thyroid function tests within the reference range, and to investigate the effect of thyroxine treatment on psychological and physical wellbeing in healthy participants. Sixty ambulatory patients with primary hypothyroidism receiving levothyroxine (L-T4 participated in the study. Patients were divided into 2 groups according to their TSH level. The first group was in TSH low-normal range (0.4–2.0 mU/l, the second in upper-normal (2.1–4.0 mU/l range. We analyzed the results of several tests: “12 classical hypothyroidism symp- toms”, SF36, HARS, HDRS, Zung scale at baseline and in 3 months. With a small-dose changes we cross the groups to compare the results. Results: At baseline analyze there was a small differ-ence between two groups. Women with in the upper-normal TSH range had more expressed symptoms of hypothyroidism. After small changes in thyroxine treatment we could not say that the clinical picture of a hypothyroidism has changed cardinally, however, it is necessary to notice that there was dynamics of separate symptoms. The same picture was noticed with the depression and anxiety levels. The meanings were rather close and small dose changes in L-T4 treatment were more expressed in group with upper-normal range. The positive dynamics of well-being after dose changing were registered in both groups. Conclusion: Small changes in T4 dosage do not produce measurable changes in hypothyroid symptoms, well-being, or quality of life.

  18. Note: A 102 dB dynamic-range charge-sampling readout for ionizing particle/radiation detectors based on an application-specific integrated circuit (ASIC)

    Science.gov (United States)

    Pullia, A.; Zocca, F.; Capra, S.

    2018-02-01

    An original technique for the measurement of charge signals from ionizing particle/radiation detectors has been implemented in an application-specific integrated circuit form. The device performs linear measurements of the charge both within and beyond its output voltage swing. The device features an unprecedented spectroscopic dynamic range of 102 dB and is suitable for high-resolution ion and X-γ ray spectroscopy. We believe that this approach may change a widespread paradigm according to which no high-resolution spectroscopy is possible when working close to or beyond the limit of the preamplifier's output voltage swing.

  19. Evaluation of dynamic range for LLNL streak cameras using high contrast pulses and pulse podiatry'' on the Nova laser system

    Energy Technology Data Exchange (ETDEWEB)

    Richards, J.B.; Weiland, T.L.; Prior, J.A.

    1990-07-01

    A standard LLNL streak camera has been used to analyze high contrast pulses on the Nova laser facility. These pulses have a plateau at their leading edge (foot) with an amplitude which is approximately 1% of the maximum pulse height. Relying on other features of the pulses and on signal multiplexing, we were able to determine how accurately the foot amplitude was being represented by the camera. Results indicate that the useful single channel dynamic range of the instrument approaches 100:1. 1 ref., 4 figs., 1 tab.

  20. Hydrologic transport of depleted uranium associated with open air dynamic range testing at Los Alamos National Laboratory, New Mexico, and Eglin Air Force Base, Florida

    International Nuclear Information System (INIS)

    Becker, N.M.; Vanta, E.B.

    1995-01-01

    Hydrologic investigations on depleted uranium fate and transport associated with dynamic testing activities were instituted in the 1980's at Los Alamos National Laboratory and Eglin Air Force Base. At Los Alamos, extensive field watershed investigations of soil, sediment, and especially runoff water were conducted. Eglin conducted field investigations and runoff studies similar to those at Los Alamos at former and active test ranges. Laboratory experiments complemented the field investigations at both installations. Mass balance calculations were performed to quantify the mass of expended uranium which had transported away from firing sites. At Los Alamos, it is estimated that more than 90 percent of the uranium still remains in close proximity to firing sites, which has been corroborated by independent calculations. At Eglin, we estimate that 90 to 95 percent of the uranium remains at test ranges. These data demonstrate that uranium moves slowly via surface water, in both semi-arid (Los Alamos) and humid (Eglin) environments

  1. Hydrologic transport of depleted uranium associated with open air dynamic range testing at Los Alamos National Laboratory, New Mexico, and Eglin Air Force Base, Florida

    Energy Technology Data Exchange (ETDEWEB)

    Becker, N.M. [Los Alamos National Lab., NM (United States); Vanta, E.B. [Wright Laboratory Armament Directorate, Eglin Air Force Base, FL (United States)

    1995-05-01

    Hydrologic investigations on depleted uranium fate and transport associated with dynamic testing activities were instituted in the 1980`s at Los Alamos National Laboratory and Eglin Air Force Base. At Los Alamos, extensive field watershed investigations of soil, sediment, and especially runoff water were conducted. Eglin conducted field investigations and runoff studies similar to those at Los Alamos at former and active test ranges. Laboratory experiments complemented the field investigations at both installations. Mass balance calculations were performed to quantify the mass of expended uranium which had transported away from firing sites. At Los Alamos, it is estimated that more than 90 percent of the uranium still remains in close proximity to firing sites, which has been corroborated by independent calculations. At Eglin, we estimate that 90 to 95 percent of the uranium remains at test ranges. These data demonstrate that uranium moves slowly via surface water, in both semi-arid (Los Alamos) and humid (Eglin) environments.

  2. Short-range surface plasmonics: Localized electron emission dynamics from a 60-nm spot on an atomically flat single-crystalline gold surface.

    Science.gov (United States)

    Frank, Bettina; Kahl, Philip; Podbiel, Daniel; Spektor, Grisha; Orenstein, Meir; Fu, Liwei; Weiss, Thomas; Horn-von Hoegen, Michael; Davis, Timothy J; Meyer Zu Heringdorf, Frank-J; Giessen, Harald

    2017-07-01

    We experimentally and theoretically visualize the propagation of short-range surface plasmon polaritons using atomically flat single-crystalline gold platelets on silicon substrates. We study their excitation and subfemtosecond dynamics via normal-incidence two-photon photoemission electron microscopy. By milling a plasmonic disk and grating structure into a single-crystalline gold platelet, we observe nanofocusing of the short-range surface plasmon polariton. Localized two-photon ultrafast electron emission from a spot with a smallest dimension of 60 nm is observed. Our novel approach opens the door toward reproducible plasmonic nanofocusing devices, which do not degrade upon high light intensity or heating due to the atomically flat surface without any tips, protrusions, or holes. Our nanofoci could also be used as local emitters for ultrafast electron bunches in time-resolved electron microscopes.

  3. Oligonucleotide-functionalized gold nanoparticles-enhanced QCM-D sensor for mercury(II) ions with high sensitivity and tunable dynamic range.

    Science.gov (United States)

    Chen, Qiang; Wu, Xiaojie; Wang, Dingzhong; Tang, Wei; Li, Na; Liu, Feng

    2011-06-21

    A quartz crystal microbalance with dissipation monitoring (QCM-D) sensor was developed for highly sensitive and specific detection of mercury(II) ions (Hg(2+)) with a tunable dynamic range, using oligonucleotide-functionalized gold nanoparticles (GNPs) for both frequency and dissipation amplification. The fabrication of the sensor employed a 'sandwich-type' strategy, and formation of T-Hg(2+)-T structures in linker DNA reduced the hybridization of the GNPs-tagged DNA on the gold electrode, which could be used as the molecular switch for Hg(2+) sensing. This QCM-D mercury sensor showed a linear response of 10-200 nM, with detection limits of 4 nM and 7 nM for frequency and dissipation measurements, respectively. Moreover, the dynamic range of the sensor could be tuned by simply altering the concentration of linker DNA without designing new sensors in the cases where detection of Hg(2+) at different levels is required. This sensor afforded excellent selectivity toward Hg(2+) compared with other potential coexisting metal ions. The feasibility of the sensor was demonstrated by analyzing Hg(2+)-spiked tap- and lake-water samples with satisfactory recoveries. The proposed approach extended the application of the QCM-D system in metal ions sensing, and could be adopted for the detection of other analytes when complemented with the use of functional DNA structures.

  4. Online Energy Management of Plug-In Hybrid Electric Vehicles for Prolongation of All-Electric Range Based on Dynamic Programming

    Directory of Open Access Journals (Sweden)

    Zeyu Chen

    2015-01-01

    Full Text Available The employed energy management strategy plays an important role in energy saving performance and exhausted emission reduction of plug-in hybrid electric vehicles (HEVs. An application of dynamic programming for optimization of power allocation is implemented in this paper with certain driving cycle and a limited driving range. Considering the DP algorithm can barely be used in real-time control because of its huge computational task and the dependence on a priori driving cycle, several online useful control rules are established based on the offline optimization results of DP. With the above efforts, an online energy management strategy is proposed finally. The presented energy management strategy concerns the prolongation of all-electric driving range as well as the energy saving performance. A simulation study is deployed to evaluate the control performance of the proposed energy management approach. All-electric range of the plug-in HEV can be prolonged by up to 2.86% for a certain driving condition. The energy saving performance is relative to the driving distance. The presented energy management strategy brings a little higher energy cost when driving distance is short, but for a long driving distance, it can reduce the energy consumption by up to 5.77% compared to the traditional CD-CS strategy.

  5. Connection Between Thermodynamics and Dynamics of Simple Fluids in Pores: Impact of Fluid-Fluid Interaction Range and Fluid-Solid Interaction Strength.

    Science.gov (United States)

    Krekelberg, William P; Siderius, Daniel W; Shen, Vincent K; Truskett, Thomas M; Errington, Jeffrey R

    2017-08-03

    Using molecular simulations, we investigate how the range of fluid-fluid (adsorbate-adsorbate) interactions and the strength of fluid-solid (adsorbate-adsorbent) interactions impact the strong connection between distinct adsorptive regimes and distinct self-diffusivity regimes reported in [Krekelberg, W. P.; Siderius, D. W.; Shen, V. K.; Truskett, T. M.; Errington, J. R. Langmuir 2013 , 29 , 14527-14535]. Although increasing the fluid-fluid interaction range changes both the thermodynamics and the dynamic properties of adsorbed fluids, the previously reported connection between adsorptive filling regimes and self-diffusivity regimes remains. Increasing the fluid-fluid interaction range leads to enhanced layering and decreased self-diffusivity in the multilayer-formation regime but has little effect on the properties within film-formation and pore-filling regimes. We also find that weakly attractive adsorbents, which do not display distinct multilayer formation, are hard-sphere-like at super- and subcritical temperatures. In this case, the self-diffusivity of the confined and bulk fluid has a nearly identical scaling-relationship with effective density.

  6. A Low-Power Single-Bit Continuous-Time ΔΣ Converter with 92.5 dB Dynamic Range for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Vishal Saxena

    2012-07-01

    Full Text Available A third-order single-bit CT-ΔΣ modulator for generic biomedical applications is implemented in a 0.15 µm FDSOI CMOS process. The overall power efficiency is attained by employing a single-bit ΔΣ and a subthreshold FDSOI process. The loop-filter coefficients are determined using a systematic design centering approach by accounting for the integrator non-idealities. The single-bit CT-ΔΣ modulator consumes 110 µW power from a 1.5 V power supply when clocked at 6.144 MHz. The simulation results for the modulator exhibit a dynamic range of 94.4 dB and peak SNDR of 92.4 dB for 6 kHz signal bandwidth. The figure of merit (FoM for the third-order, single-bit CT-ΔΣ modulator is 0.271 pJ/level.

  7. A 1-V 60-μW 85-dB dynamic range continuous-time third-order sigma-delta modulator

    International Nuclear Information System (INIS)

    Li Yuanwen; Qi Da; Dong Yifeng; Xu Jun; Ren Junyan

    2009-01-01

    A 1-V third order one-bit continuous-time (CT) EA modulator is presented. Designed in the SMIC mixed-signal 0.13-μm CMOS process, the modulator utilizes active RC integrators to implement the loop filter. An efficient circuit design methodology for the CT ΣΔ modulator is proposed and verified. Low power dissipation is achieved through the use of two-stage class A/AB amplifiers. The presented modulator achieves 81.4-dB SNDR and 85-dB dynamic range in a 20-kHz bandwidth with an over sampling ratio of 128. The total power consumption of the modulator is only 60 μW from a 1-V power supply and the prototype occupies an active area of 0.12 mm 2 . (semiconductor integrated circuits)

  8. Optimized droplet digital CFU assay (ddCFU) provides precise quantification of bacteria over a dynamic range of 6 logs and beyond.

    Science.gov (United States)

    Scheler, O; Pacocha, N; Debski, P R; Ruszczak, A; Kaminski, T S; Garstecki, P

    2017-05-31

    Standard digital assays need a large number of compartments for precise quantification of a sample over a broad dynamic range. We address this issue with an optimized droplet digital approach that uses a drastically reduced number of compartments for quantification. We generate serial logarithmic dilutions of an initial bacterial sample as an array of microliter-sized droplet plugs. In a subsequent step, these droplets are split into libraries of nanoliter droplets and pooled together for incubation and analysis. We show that our technology is at par with traditional dilution plate count for quantification of bacteria, but has the advantage of simplifying the experimental setup and reducing the manual workload. The method also has the potential to reduce the assay time significantly.

  9. Measurement of high-dynamic range x-ray Thomson scattering spectra for the characterization of nano-plasmas at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, M. J., E-mail: macdonm@umich.edu [University of Michigan, Ann Arbor, Michigan 48109 (United States); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Gorkhover, T. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Technische Universität, 10623 Berlin (Germany); Bachmann, B.; Hau-Riege, S. P.; Pardini, T.; Döppner, T. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Bucher, M. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Argonne National Lab, Lemont, Illinois 60439 (United States); Carron, S. [California Lutheran University, Thousand Oaks, California 91360 (United States); Coffee, R. N.; Fletcher, L. B.; Gamboa, E. J.; Glenzer, S. H.; Göde, S.; Krzywinski, J.; O’Grady, C. P.; Osipov, T.; Swiggers, M. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Drake, R. P. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Ferguson, K. R. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford University, Stanford, California 94305 (United States); Kraus, D. [University of California, Berkeley, California 94720 (United States); and others

    2016-11-15

    Atomic clusters can serve as ideal model systems for exploring ultrafast (∼100 fs) laser-driven ionization dynamics of dense matter on the nanometer scale. Resonant absorption of optical laser pulses enables heating to temperatures on the order of 1 keV at near solid density conditions. To date, direct probing of transient states of such nano-plasmas was limited to coherent x-ray imaging. Here we present the first measurement of spectrally resolved incoherent x-ray scattering from clusters, enabling measurements of transient temperature, densities, and ionization. Single shot x-ray Thomson scattering signals were recorded at 120 Hz using a crystal spectrometer in combination with a single-photon counting and energy-dispersive pnCCD. A precise pump laser collimation scheme enabled recording near background-free scattering spectra from Ar clusters with an unprecedented dynamic range of more than 3 orders of magnitude. Such measurements are important for understanding collective effects in laser-matter interactions on femtosecond time scales, opening new routes for the development of schemes for their ultrafast control.

  10. On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1-20 GHz

    Science.gov (United States)

    Fannin, P. C.; Vekas, L.; Marin, C. N.; Malaescu, I.

    2017-02-01

    Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ‧(ω, Η)-iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1-20 GHz and polarising fields 0-168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4-6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz.

  11. Climate change and fire effects on a prairie-woodland ecotone: projecting species range shifts with a dynamic global vegetation model

    Science.gov (United States)

    King, David A.; Bachelet, Dominique M.; Symstad, Amy J.

    2013-01-01

    Large shifts in species ranges have been predicted under future climate scenarios based primarily on niche-based species distribution models. However, the mechanisms that would cause such shifts are uncertain. Natural and anthropogenic fires have shaped the distributions of many plant species, but their effects have seldom been included in future projections of species ranges. Here, we examine how the combination of climate and fire influence historical and future distributions of the ponderosa pine–prairie ecotone at the edge of the Black Hills in South Dakota, USA, as simulated by MC1, a dynamic global vegetation model that includes the effects of fire, climate, and atmospheric CO2 concentration on vegetation dynamics. For this purpose, we parameterized MC1 for ponderosa pine in the Black Hills, designating the revised model as MC1-WCNP. Results show that fire frequency, as affected by humidity and temperature, is central to the simulation of historical prairies in the warmer lowlands versus woodlands in the cooler, moister highlands. Based on three downscaled general circulation model climate projections for the 21st century, we simulate greater frequencies of natural fire throughout the area due to substantial warming and, for two of the climate projections, lower relative humidity. However, established ponderosa pine forests are relatively fire resistant, and areas that were initially wooded remained so over the 21st century for most of our future climate x fire management scenarios. This result contrasts with projections for ponderosa pine based on climatic niches, which suggest that its suitable habitat in the Black Hills will be greatly diminished by the middle of the 21st century. We hypothesize that the differences between the future predictions from these two approaches are due in part to the inclusion of fire effects in MC1, and we highlight the importance of accounting for fire as managed by humans in assessing both historical species distributions

  12. Paper-based solid-phase multiplexed nucleic acid hybridization assay with tunable dynamic range using immobilized quantum dots as donors in fluorescence resonance energy transfer.

    Science.gov (United States)

    Noor, M Omair; Krull, Ulrich J

    2013-08-06

    A multiplexed solid-phase nucleic acid hybridization assay on a paper-based platform is presented using multicolor immobilized quantum dots (QDs) as donors in fluorescence resonance energy transfer (FRET). The surface of paper was modified with imidazole groups to immobilize two types of QD-probe oligonucleotide conjugates that were assembled in solution. Green-emitting QDs (gQDs) and red-emitting QDs (rQDs) served as donors with Cy3 and Alexa Fluor 647 (A647) acceptors. The gQD/Cy3 FRET pair served as an internal standard, while the rQD/A647 FRET pair served as a detection channel, combining the control and analytical test zones in one physical location. Hybridization of dye-labeled oligonucleotide targets provided the proximity for FRET sensitized emission from the acceptor dyes, which served as an analytical signal. Hybridization assays in the multicolor format provided a limit of detection of 90 fmol and an upper limit of dynamic range of 3.5 pmol. The use of an array of detection zones was designed to provide improved analytical figures of merit compared to that which could be achieved on one type of array design in terms of relative concentration of multicolor QDs. The hybridization assays showed excellent resistance to nonspecific adsorption of oligonucleotides. Selectivity of the two-plex hybridization assay was demonstrated by single nucleotide polymorphism (SNP) detection at a contrast ratio of 50:1. Additionally, it is shown that the use of preformed QD-probe oligonucleotide conjugates and consideration of the relative number density of the two types of QD-probe conjugates in the two-color assay format is advantageous to maximize assay sensitivity and the upper limit of dynamic range.

  13. Visual detection of telomerase activity with a tunable dynamic range by using a gold nanoparticle probe-based hybridization protection strategy

    Science.gov (United States)

    Wang, Jiasi; Wu, Li; Ren, Jinsong; Qu, Xiaogang

    2014-01-01

    We developed a novel telomere complementary (TC) oligonucleotide modified AuNP probe (TC-AuNPs) for colorimetric analysis of telomerase activity. The mechanism of this method is that the telomerase reaction products (TRP), which can hybridize with the TC-AuNPs, are able to protect the AuNPs from the aggregation induced by salt. It is demonstrated that the colorimetric method enabled the analysis of the telomerase activity in 1000 HeLa cells with the naked eye, and down to 100 HeLa cells with the aid of UV-Vis spectroscopy. This strategy is not only convenient and sensitive, but also has a tunable dynamic range. The platform is also applicable for the initial screening of a telomerase inhibitor to discover new anticancer drugs.We developed a novel telomere complementary (TC) oligonucleotide modified AuNP probe (TC-AuNPs) for colorimetric analysis of telomerase activity. The mechanism of this method is that the telomerase reaction products (TRP), which can hybridize with the TC-AuNPs, are able to protect the AuNPs from the aggregation induced by salt. It is demonstrated that the colorimetric method enabled the analysis of the telomerase activity in 1000 HeLa cells with the naked eye, and down to 100 HeLa cells with the aid of UV-Vis spectroscopy. This strategy is not only convenient and sensitive, but also has a tunable dynamic range. The platform is also applicable for the initial screening of a telomerase inhibitor to discover new anticancer drugs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr05185d

  14. Climate change and fire effects on a prairie-woodland ecotone: projecting species range shifts with a dynamic global vegetation model.

    Science.gov (United States)

    King, David A; Bachelet, Dominique M; Symstad, Amy J

    2013-12-01

    Large shifts in species ranges have been predicted under future climate scenarios based primarily on niche-based species distribution models. However, the mechanisms that would cause such shifts are uncertain. Natural and anthropogenic fires have shaped the distributions of many plant species, but their effects have seldom been included in future projections of species ranges. Here, we examine how the combination of climate and fire influence historical and future distributions of the ponderosa pine-prairie ecotone at the edge of the Black Hills in South Dakota, USA, as simulated by MC1, a dynamic global vegetation model that includes the effects of fire, climate, and atmospheric CO2 concentration on vegetation dynamics. For this purpose, we parameterized MC1 for ponderosa pine in the Black Hills, designating the revised model as MC1-WCNP. Results show that fire frequency, as affected by humidity and temperature, is central to the simulation of historical prairies in the warmer lowlands versus woodlands in the cooler, moister highlands. Based on three downscaled general circulation model climate projections for the 21st century, we simulate greater frequencies of natural fire throughout the area due to substantial warming and, for two of the climate projections, lower relative humidity. However, established ponderosa pine forests are relatively fire resistant, and areas that were initially wooded remained so over the 21st century for most of our future climate x fire management scenarios. This result contrasts with projections for ponderosa pine based on climatic niches, which suggest that its suitable habitat in the Black Hills will be greatly diminished by the middle of the 21st century. We hypothesize that the differences between the future predictions from these two approaches are due in part to the inclusion of fire effects in MC1, and we highlight the importance of accounting for fire as managed by humans in assessing both historical species distributions and

  15. Co‐occurrence dynamics of endangered Lower Keys marsh rabbits and free‐ranging domestic cats: Prey responses to an exotic predator removal program

    Science.gov (United States)

    Cove, Michael V.; Gardner, Beth; Simons, Theodore R.; O'Connell, Allan F.

    2018-01-01

    The Lower Keys marsh rabbit (Sylvilagus palustris hefneri) is one of many endangered endemic species of the Florida Keys. The main threats are habitat loss and fragmentation from sea‐level rise, development, and habitat succession. Exotic predators such as free‐ranging domestic cats (Felis catus) pose an additional threat to these endangered small mammals. Management strategies have focused on habitat restoration and exotic predator control. However, the effectiveness of predator removal and the effects of anthropogenic habitat modifications and restoration have not been evaluated. Between 2013 and 2015, we used camera traps to survey marsh rabbits and free‐ranging cats at 84 sites in the National Key Deer Refuge, Big Pine Key, Florida, USA. We used dynamic occupancy models to determine factors associated with marsh rabbit occurrence, colonization, extinction, and the co‐occurrence of marsh rabbits and cats during a period of predator removal. Rabbit occurrence was positively related to freshwater habitat and patch size, but was negatively related to the number of individual cats detected at each site. Furthermore, marsh rabbit colonization was negatively associated with relative increases in the number of individual cats at each site between survey years. Cat occurrence was negatively associated with increasing distance from human developments. The probability of cat site extinction was positively related to a 2‐year trapping effort, indicating that predator removal reduced the cat population. Dynamic co‐occurrence models suggested that cats and marsh rabbits co‐occur less frequently than expected under random conditions, whereas co‐detections were site and survey‐specific. Rabbit site extinction and colonization were not strongly conditional on cat presence, but corresponded with a negative association. Our results suggest that while rabbits can colonize and persist at sites where cats occur, it is the number of individual cats at a site that

  16. A range of newly developed mobile generators to dynamically produce SI-traceable reference gas mixtures for reactive compounds at atmospheric concentrations

    Science.gov (United States)

    Leuenberger, Daiana; Pascale, Céline; Guillevic, Myriam; Ackermann, Andreas; Niederhauser, Bernhard

    2017-04-01

    Three new mobile facilities have been developed at METAS to dynamically generate SI-traceable reference gas mixtures for a variety of reactive compounds at atmospheric amount of substance fractions and at very low levels of uncertainty (Ux balance. The carrier gas is previously purified from the compounds of interest using commercially available purification cartridges. The permeation chambers of ReGaS2 and ReGaS3 have multiple individual cells allowing for the generation of mixtures containing up to 5 different components if required. ReGaS1 allows for the generation of one-component mixtures only. These primary mixtures are then diluted to the required amount of substance fractions using thermal mass flow controllers for full flexibility and adaptability of the generation process over the entire range of possible concentrations. In order to considerably reduce adsorption/desorption processes and thus stabilisation time, all electro-polished stainless steel parts of ReGaS1 and ReGaS2 in contact with the reference gas mixtures are passivated with SilcoNert2000® surface coating. These three state-of-the-art mobile reference gas generators are applicable under both, laboratory and field conditions. Moreover the dynamic generation method can be adapted and applied to a large variety of molecules (e.g. BTEX, CFCs, HCFCs, HFCs and other refrigerants) and is particularly suitable for reactive gas species and/or at concentration ranges which are unstable when stored in pressurised cylinders. Acknowledgement: This work was supported by the European Metrology Research Programme (EMRP). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union

  17. Capillary isoelectric focusing of microorganisms in the pH range 2-5 in a dynamically modified FS capillary with UV detection.

    Science.gov (United States)

    Horká, Marie; Růzicka, Filip; Holá, Veronika; Slais, Karel

    2006-07-01

    The isoelectric points of many microbial cells lie within the pH range spanning from 1.5 to 4.5. In this work, we suggest a CIEF method for the separation of cells according to their isoelectric points in the pH range of 2-5. It includes the segmental injection of the sample pulse composed of the segment of the selected simple ampholytes, the segment of the bioanalytes and the segment of carrier ampholytes into fused silica capillaries dynamically modified by poly(ethylene glycole). This polymer dissolved in the catholyte, in the anolyte and in the injected sample pulse was used for a prevention of the bioanalyte adsorption on the capillary surface and for the reduction of the electroosmotic flow. Between each focusing run, the capillaries were washed with the mixture of acetone/ethanol to achieve the reproducible and efficient CIEF. In order to trace of pH gradients, low-molecular-mass pI markers were used. The mixed cultures of microorganisms, Escherichia coli CCM 3954, Candida albicans CCM 8180, Candida parapsilosis, Candida krusei, Candida glabrata, Candida tropicalis, CCM 8223, Proteus vulgaris, Klebsiela pneumoniae, Staphylococcus aureus CCM 3953, Streptococcus agalactiae CCM 6187, Enterococcus faecalis CCM 4224 and Staphylococcus epidermidis CCM 4418, were focused and separated by the CIEF method suggested here. This CIEF method enables the separation and detection of the microbes from the mixed cultures within several minutes. The minimum detectable number of microbial cells was less than 10(3).

  18. An autonomous multisensor in situ metrology system for enabling high dynamic range measurement of 3D surfaces on precision machine tools

    International Nuclear Information System (INIS)

    Liu, Samuel M Y; Cheung, Benny C F; Cheng, Ching-Hsiang; Whitehouse, David

    2016-01-01

    An in situ measurement is of prime importance when trying to maintain the position of the workpiece for further compensation processes in order to improve the accuracy and efficiency of the precision machining of three dimensional (3D) surfaces. However, the coordinates of most of the machine tools with closed machine interfaces and control system are not accessible for users, which make it difficult to use the motion axes of the machine tool for in situ measurements. This paper presents an autonomous multisensor in situ metrology system for enabling high dynamic range measurement of 3D surfaces on precision machine tools. It makes use of a designed tool path and an additional motion sensor to assist the registration of time-space data for the position estimation of a 2D laser scanner which measures the surface with a high lateral resolution and large area without the need to interface with the machine tool system. A prototype system was built and integrated into an ultra-precision polishing machine. Experimental results show that it measures the 3D surfaces with high resolution, high repeatability, and large measurement range. The system not only improves the efficiency and accuracy of the precision machining process but also extends the capability of machine tools. (paper)

  19. Seasonality in cholera dynamics : a rainfall-driven model explains the wide range of patterns of an infectious disease in endemic areas

    Science.gov (United States)

    Baracchini, Theo; Pascual, Mercedes; King, Aaron A.; Bouma, Menno J.; Bertuzzo, Enrico; Rinaldo, Andrea

    2015-04-01

    An explanation for the spatial variability of seasonal cholera patterns has remained an unresolved problem in tropical medicine te{pascual_2002}. Previous studies addressing the role of climate drivers in disease dynamics have focused on interannual variability and modelled seasonality as given te{king_nature}. Explanations for seasonality have relied on complex environmental interactions that vary with spatial location (involving regional hydrological models te{bertuzzo_2012}, river discharge, sea surface temperature, and plankton blooms). Thus, no simple and unified theory based on local climate variables has been formulated te{emch_2008}, leaving our understanding of seasonal variations of cholera outbreaks in different regions of the world incomplete. Through the analysis of a unique historical dataset containing 50 years of monthly meteorological, demographic and epidemiological records, we propose a mechanistic, SIR-based stochastic model for the population dynamics of cholera driven by local rainfall and temperature that is able to capture the full range of seasonal patterns in this large estuarine region, which encompasses the variety of patterns worldwide. Parameter inference was implemented via new statistical methods that allow the computation of maximum-likelihood estimates for partially observed Markov processes through sequential Monte-Carlo te{ionides_2011}. Such a model may provide a unprecedented opportunity to gain insights on the conditions and factors responsible for endemicity around the globe, and therefore, to also revise our understanding of the ecology of Vibrio cholerae. Results indicate that the hydrological regime is a decisive driver determining the seasonal dynamics of cholera. It was found that rainfall and longer water residence times tend to buffer the propagation of the disease in wet regions due to a dilution effect, while also enhancing cholera incidence in dry regions. This indicates that overall water levels matter and appear

  20. Unmanned Aerial Vehicle (UAV) Dynamic-Tracking Directional Wireless Antennas for Low Powered Applications that Require Reliable Extended Range Operations in Time Critical Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Scott G. Bauer; Matthew O. Anderson; James R. Hanneman

    2005-10-01

    The proven value of DOD Unmanned Aerial Vehicles (UAVs) will ultimately transition to National and Homeland Security missions that require real-time aerial surveillance, situation awareness, force protection, and sensor placement. Public services first responders who routinely risk personal safety to assess and report a situation for emergency actions will likely be the first to benefit from these new unmanned technologies. ‘Packable’ or ‘Portable’ small class UAVs will be particularly useful to the first responder. They require the least amount of training, no fixed infrastructure, and are capable of being launched and recovered from the point of emergency. All UAVs require wireless communication technologies for real- time applications. Typically on a small UAV, a low bandwidth telemetry link is required for command and control (C2), and systems health monitoring. If the UAV is equipped with a real-time Electro-Optical or Infrared (EO/Ir) video camera payload, a dedicated high bandwidth analog/digital link is usually required for reliable high-resolution imagery. In most cases, both the wireless telemetry and real-time video links will be integrated into the UAV with unity gain omni-directional antennas. With limited on-board power and payload capacity, a small UAV will be limited with the amount of radio-frequency (RF) energy it transmits to the users. Therefore, ‘packable’ and ‘portable’ UAVs will have limited useful operational ranges for first responders. This paper will discuss the limitations of small UAV wireless communications. The discussion will present an approach of utilizing a dynamic ground based real-time tracking high gain directional antenna to provide extend range stand-off operation, potential RF channel reuse, and assured telemetry and data communications from low-powered UAV deployed wireless assets.

  1. Vibrotactile Presentation of Musical Notes to the Glabrous Skin for Adults with Normal Hearing or a Hearing Impairment: Thresholds, Dynamic Range and High-Frequency Perception.

    Directory of Open Access Journals (Sweden)

    Carl Hopkins

    Full Text Available Presentation of music as vibration to the skin has the potential to facilitate interaction between musicians with hearing impairments and other musicians during group performance. Vibrotactile thresholds have been determined to assess the potential for vibrotactile presentation of music to the glabrous skin of the fingertip, forefoot and heel. No significant differences were found between the thresholds for sinusoids representing notes between C1 and C6 when presented to the fingertip of participants with normal hearing and with a severe or profound hearing loss. For participants with normal hearing, thresholds for notes between C1 and C6 showed the characteristic U-shape curve for the fingertip, but not for the forefoot and heel. Compared to the fingertip, the forefoot had lower thresholds between C1 and C3, and the heel had lower thresholds between C1 and G2; this is attributed to spatial summation from the Pacinian receptors over the larger contactor area used for the forefoot and heel. Participants with normal hearing assessed the perception of high-frequency vibration using 1s sinusoids presented to the fingertip and were found to be more aware of transient vibration at the beginning and/or end of notes between G4 and C6 when stimuli were presented 10dB above threshold, rather than at threshold. An average of 94% of these participants reported feeling continuous vibration between G4 and G5 with stimuli presented 10dB above threshold. Based on the experimental findings and consideration of health effects relating to vibration exposure, a suitable range of notes for vibrotactile presentation of music is identified as being from C1 to G5. This is more limited than for human hearing but the fundamental frequencies of the human voice, and the notes played by many instruments, lie within it. However, the dynamic range might require compression to avoid the negative effects of amplitude on pitch perception.

  2. Vibrotactile Presentation of Musical Notes to the Glabrous Skin for Adults with Normal Hearing or a Hearing Impairment: Thresholds, Dynamic Range and High-Frequency Perception.

    Science.gov (United States)

    Hopkins, Carl; Maté-Cid, Saúl; Fulford, Robert; Seiffert, Gary; Ginsborg, Jane

    2016-01-01

    Presentation of music as vibration to the skin has the potential to facilitate interaction between musicians with hearing impairments and other musicians during group performance. Vibrotactile thresholds have been determined to assess the potential for vibrotactile presentation of music to the glabrous skin of the fingertip, forefoot and heel. No significant differences were found between the thresholds for sinusoids representing notes between C1 and C6 when presented to the fingertip of participants with normal hearing and with a severe or profound hearing loss. For participants with normal hearing, thresholds for notes between C1 and C6 showed the characteristic U-shape curve for the fingertip, but not for the forefoot and heel. Compared to the fingertip, the forefoot had lower thresholds between C1 and C3, and the heel had lower thresholds between C1 and G2; this is attributed to spatial summation from the Pacinian receptors over the larger contactor area used for the forefoot and heel. Participants with normal hearing assessed the perception of high-frequency vibration using 1s sinusoids presented to the fingertip and were found to be more aware of transient vibration at the beginning and/or end of notes between G4 and C6 when stimuli were presented 10dB above threshold, rather than at threshold. An average of 94% of these participants reported feeling continuous vibration between G4 and G5 with stimuli presented 10dB above threshold. Based on the experimental findings and consideration of health effects relating to vibration exposure, a suitable range of notes for vibrotactile presentation of music is identified as being from C1 to G5. This is more limited than for human hearing but the fundamental frequencies of the human voice, and the notes played by many instruments, lie within it. However, the dynamic range might require compression to avoid the negative effects of amplitude on pitch perception.

  3. A 13µW 87dB dynamic range implantable ΔΣ modulator for full-spectrum neural recording.

    Science.gov (United States)

    Xu, Jian; Islam, Md Kafiul; Wang, Shuo; Yang, Zhi

    2013-01-01

    Experiment analysis on in-vivo data sequences suggests a wide system dynamic range (DR) is required to simultaneously record local field potentials (LFPs), extra-cellular spikes, and artifacts/interferences. In this paper, we present a 13 µW 87 dB DR ΔΣ modulator for full-spectrum neural recording. To achieve a wide DR and low power consumption, a fully-differential topology is used with multi-bit (MB) quantization scheme and switched-opamp (SO) technique. By adopting a novel fully-clocked scheme, a power-efficient current-mirror SO is developed with 50% power saving, which doubles the figure-of-merit (FOM) over its counterpart. A new static power-less multi-bit quantizer with 96% power and 69% area reduction is also introduced. Besides, instead of metal-insulator-metal (MIM) capacitor, three high-density MOS capacitor (MOSCAP) structures are employed to reduce circuit area. Measurement results show a peak signal-to-noise and distortion ratio (SNDR) of 85 dB with 10 kHz bandwidth at 1.0 V supply, corresponding to an FOM of 45 fJ/conv.-step. which is implemented in a 0.18 µm CMOS.

  4. A frequency shaping neural recorder with 3 pF input capacitance and 11 plus 4.5 bits dynamic range.

    Science.gov (United States)

    Xu, Jian; Wu, Tong; Liu, Wentai; Yang, Zhi

    2014-08-01

    This paper presents a frequency-shaping (FS) neural recording architecture and its implementation in a 0.13 μ m CMOS process. Compared with its conventional counterpart, the proposed architecture inherently rejects electrode offset, increases input impedance 5-10 fold, compresses neural data dynamic range (DR) by 4.5-bit, simultaneously records local field potentials (LFPs) and extracellular spikes, and is more suitable for long-term recording experiments. Measured at a 40 kHz sampling clock and ± 0.6 V supply, the recorder consumes 50 μW/ch, of which 22 μW per FS amplifier, 24 μ W per buffer, 4 μ W per 11-bit successive approximation register analog-to-digital converter (SAR ADC). The input-referred noise for LFPs and extracellular spikes are 13 μ Vrms and 7 μVrms, respectively, which are sufficient to achieve high-fidelity full-spectrum neural data. In addition, the designed recorder has a 3 pF input capacitance and allows " 11+4.5"-bit neural data DR without system saturation, where the extra 4.5-bit owes to the FS technique. Its figure-of-merit (FOM) based on data DR reaches 36.0 fJ/conversion-step.

  5. Ab initio molecular dynamics model for density, elastic properties and short range order of Co-Fe-Ta-B metallic glass thin films

    International Nuclear Information System (INIS)

    Hostert, C; Music, D; Schneider, J M; Bednarcik, J; Keckes, J; Kapaklis, V; Hjörvarsson, B

    2011-01-01

    Density, elastic modulus and the pair distribution function of Co-Fe-Ta-B metallic glasses were obtained by ab initio molecular dynamics simulations and measured for sputtered thin films using x-ray reflectivity, nanoindentation and x-ray diffraction using high energy photons. The computationally obtained density of 8.19 g cm -3 for Co 43 Fe 20 Ta 5.5 B 31.5 and 8.42 g cm -3 for Co 45.5 Fe 24 Ta 6 B 24.5 , as well as the Young’s moduli of 273 and 251 GPa, respectively, are consistent with our experiments and literature data. These data, together with the good agreement between the theoretical and the experimental pair distribution functions, indicate that the model established here is useful to describe the density, elasticity and short range order of Co-Fe-Ta-B metallic glass thin films. Irrespective of the investigated variation in chemical composition, (Co, Fe)-B cluster formation and Co-Fe interactions are identified by density-of-states analysis. Strong bonds within the structural units and between the metallic species may give rise to the comparatively large stiffness. (paper)

  6. A Sound Therapy-Based Intervention to Expand the Auditory Dynamic Range for Loudness among Persons with Sensorineural Hearing Losses: A Randomized Placebo-Controlled Clinical Trial

    Science.gov (United States)

    Formby, Craig; Hawley, Monica L.; Sherlock, LaGuinn P.; Gold, Susan; Payne, JoAnne; Brooks, Rebecca; Parton, Jason M.; Juneau, Roger; Desporte, Edward J.; Siegle, Gregory R.

    2015-01-01

    The primary aim of this research was to evaluate the validity, efficacy, and generalization of principles underlying a sound therapy–based treatment for promoting expansion of the auditory dynamic range (DR) for loudness. The basic sound therapy principles, originally devised for treatment of hyperacusis among patients with tinnitus, were evaluated in this study in a target sample of unsuccessfully fit and/or problematic prospective hearing aid users with diminished DRs (owing to their elevated audiometric thresholds and reduced sound tolerance). Secondary aims included: (1) delineation of the treatment contributions from the counseling and sound therapy components to the full-treatment protocol and, in turn, the isolated treatment effects from each of these individual components to intervention success; and (2) characterization of the respective dynamics for full, partial, and control treatments. Thirty-six participants with bilateral sensorineural hearing losses and reduced DRs, which affected their actual or perceived ability to use hearing aids, were enrolled in and completed a placebo-controlled (for sound therapy) randomized clinical trial. The 2 × 2 factorial trial design was implemented with or without various assignments of counseling and sound therapy. Specifically, participants were assigned randomly to one of four treatment groups (nine participants per group), including: (1) group 1—full treatment achieved with scripted counseling plus sound therapy implemented with binaural sound generators; (2) group 2—partial treatment achieved with counseling and placebo sound generators (PSGs); (3) group 3—partial treatment achieved with binaural sound generators alone; and (4) group 4—a neutral control treatment implemented with the PSGs alone. Repeated measurements of categorical loudness judgments served as the primary outcome measure. The full-treatment categorical-loudness judgments for group 1, measured at treatment termination, were

  7. Relationship Between Low-Velocity S-wave Anomalies, Asthenospheric Dynamics and Basaltic Volcanism in the Intraplate Setting of the Basin and Range, USA

    Science.gov (United States)

    Tibbetts, A. K.; Smith, E. I.; Conrad, C. P.; Lee, C.; Plank, T.; Yang, Y.

    2009-12-01

    were converted to km of mantle shear flow and to degrees of longitude and plotted on correspondingly sheared seismic profiles for the appropriate latitude. In all of the above cases the locations of low velocity anomalies at the times of volcanism correspond to the depth and location of volcanism. The concurrence of basaltic volcanism and low velocity seismic anomalies (hot and/or hydrous asthenosphere) at melting depths perhaps extends to the entire Basin and Range. Asthenospheric dynamics are likely an important driving factor in producing intraplate mafic volcanism. Although, Crater Flat, Death Valley, Black Rock, Big Pine, and Long Valley have temperatures and melting depths indicating asthenospheric melting, they exhibit isotopic signatures more typical of melts derived from the lithospheric mantle. This suggests that the isotopic signature of basalt may not be a good indication of source.

  8. The dynamic compressive behavior and constitutive modeling of D1 railway wheel steel over a wide range of strain rates and temperatures

    Directory of Open Access Journals (Sweden)

    Lin Jing

    Full Text Available The dynamic compressive behavior of D1 railway wheel steel at high strain rates was investigated using a split Hopkinson pressure bar (SHPB apparatus. Three types of specimens, which were derived from the different positions (i.e., the rim, web and hub of a railway wheel, were tested over a wide range of strain rates from 10−3 s−1 to 2.4 × 103 s−1 and temperatures from 213 K to 973 K. Influences of the strain rate and temperature on flow stress were discussed, and rate- and temperature-dependent constitutive relationships were assessed by the Cowper-Symonds model, Johnson-Cook model and a physically-based model, respectively. The experimental results show that the compressive true stress versus true strain response of D1 wheel steel is strain rate-dependent, and the strain hardening rate during the plastic flow stage decreases with the elevation of strain rate. Besides, the D1 wheel steel displays obvious temperature-dependence, and the third-type strain aging (3rd SA is occurred at the temperature region of 673–973 K at a strain rate of ∼1500 s−1. Comparisons of experimental results with theoretical predictions indicate that the physically-based model has a better prediction capability for the 3rd SA characteristic of the tested D1 wheel steel. Keywords: Railway wheel steel, SHPB, Strain rate, Temperature effect, Strain aging

  9. Signal-to-noise ratio improvements in laser flow diagnostics using time-resolved image averaging and high dynamic range imaging

    Science.gov (United States)

    Giassi, Davide; Long, Marshall B.

    2016-08-01

    Two alternative image readout approaches are demonstrated to improve the signal-to-noise ratio (SNR) in temporally resolved laser-based imaging experiments of turbulent phenomena. The first method exploits the temporal decay characteristics of the phosphor screens of image intensifiers when coupled to an interline-transfer CCD camera operated in double-frame mode. Specifically, the light emitted by the phosphor screen, which has a finite decay constant, is equally distributed and recorded over the two sequential frames of the detector so that an averaged image can be reconstructed. The characterization of both detector and image intensifier showed that the technique preserves the correct quantitative information, and its applicability to reactive flows was verified using planar Rayleigh scattering and tested with the acquisition of images of both steady and turbulent partially premixed methane/air flames. The comparison between conventional Rayleigh results and the averaged ones showed that the SNR of the averaged image is higher than the conventional one; with the setup used in this work, the gain in SNR was seen to approach 30 %, for both the steady and turbulent cases. The second technique uses the two-frame readout of an interline-transfer CCD to increase the image SNR based on high dynamic range imaging, and it was tested in an unsteady non-reactive flow of Freon-12 injected in air. The result showed a 15 % increase in the SNR of the low-pixel-count regions of an image, when compared to the pixels of a conventionally averaged one.

  10. An Over 90 dB Intra-Scene Single-Exposure Dynamic Range CMOS Image Sensor Using a 3.0 μm Triple-Gain Pixel Fabricated in a Standard BSI Process †

    Science.gov (United States)

    Takayanagi, Isao; Yoshimura, Norio; Mori, Kazuya; Matsuo, Shinichiro; Tanaka, Shunsuke; Abe, Hirofumi; Yasuda, Naoto; Ishikawa, Kenichiro; Okura, Shunsuke; Ohsawa, Shinji; Otaka, Toshinori

    2018-01-01

    To respond to the high demand for high dynamic range imaging suitable for moving objects with few artifacts, we have developed a single-exposure dynamic range image sensor by introducing a triple-gain pixel and a low noise dual-gain readout circuit. The developed 3 μm pixel is capable of having three conversion gains. Introducing a new split-pinned photodiode structure, linear full well reaches 40 ke−. Readout noise under the highest pixel gain condition is 1 e− with a low noise readout circuit. Merging two signals, one with high pixel gain and high analog gain, and the other with low pixel gain and low analog gain, a single exposure dynamic rage (SEHDR) signal is obtained. Using this technology, a 1/2.7”, 2M-pixel CMOS image sensor has been developed and characterized. The image sensor also employs an on-chip linearization function, yielding a 16-bit linear signal at 60 fps, and an intra-scene dynamic range of higher than 90 dB was successfully demonstrated. This SEHDR approach inherently mitigates the artifacts from moving objects or time-varying light sources that can appear in the multiple exposure high dynamic range (MEHDR) approach. PMID:29329210

  11. An Over 90 dB Intra-Scene Single-Exposure Dynamic Range CMOS Image Sensor Using a 3.0 μm Triple-Gain Pixel Fabricated in a Standard BSI Process.

    Science.gov (United States)

    Takayanagi, Isao; Yoshimura, Norio; Mori, Kazuya; Matsuo, Shinichiro; Tanaka, Shunsuke; Abe, Hirofumi; Yasuda, Naoto; Ishikawa, Kenichiro; Okura, Shunsuke; Ohsawa, Shinji; Otaka, Toshinori

    2018-01-12

    To respond to the high demand for high dynamic range imaging suitable for moving objects with few artifacts, we have developed a single-exposure dynamic range image sensor by introducing a triple-gain pixel and a low noise dual-gain readout circuit. The developed 3 μm pixel is capable of having three conversion gains. Introducing a new split-pinned photodiode structure, linear full well reaches 40 ke - . Readout noise under the highest pixel gain condition is 1 e - with a low noise readout circuit. Merging two signals, one with high pixel gain and high analog gain, and the other with low pixel gain and low analog gain, a single exposure dynamic rage (SEHDR) signal is obtained. Using this technology, a 1/2.7", 2M-pixel CMOS image sensor has been developed and characterized. The image sensor also employs an on-chip linearization function, yielding a 16-bit linear signal at 60 fps, and an intra-scene dynamic range of higher than 90 dB was successfully demonstrated. This SEHDR approach inherently mitigates the artifacts from moving objects or time-varying light sources that can appear in the multiple exposure high dynamic range (MEHDR) approach.

  12. An Over 90 dB Intra-Scene Single-Exposure Dynamic Range CMOS Image Sensor Using a 3.0 μm Triple-Gain Pixel Fabricated in a Standard BSI Process

    Directory of Open Access Journals (Sweden)

    Isao Takayanagi

    2018-01-01

    Full Text Available To respond to the high demand for high dynamic range imaging suitable for moving objects with few artifacts, we have developed a single-exposure dynamic range image sensor by introducing a triple-gain pixel and a low noise dual-gain readout circuit. The developed 3 μm pixel is capable of having three conversion gains. Introducing a new split-pinned photodiode structure, linear full well reaches 40 ke−. Readout noise under the highest pixel gain condition is 1 e− with a low noise readout circuit. Merging two signals, one with high pixel gain and high analog gain, and the other with low pixel gain and low analog gain, a single exposure dynamic rage (SEHDR signal is obtained. Using this technology, a 1/2.7”, 2M-pixel CMOS image sensor has been developed and characterized. The image sensor also employs an on-chip linearization function, yielding a 16-bit linear signal at 60 fps, and an intra-scene dynamic range of higher than 90 dB was successfully demonstrated. This SEHDR approach inherently mitigates the artifacts from moving objects or time-varying light sources that can appear in the multiple exposure high dynamic range (MEHDR approach.

  13. An Over 90 dB Intra-Scene Single-Exposure Dynamic Range CMOS Image Sensor Using a 3.0 μm Triple-Gain Pixel Fabricated in a Standard BSI Process

    OpenAIRE

    Isao Takayanagi; Norio Yoshimura; Kazuya Mori; Shinichiro Matsuo; Shunsuke Tanaka; Hirofumi Abe; Naoto Yasuda; Kenichiro Ishikawa; Shunsuke Okura; Shinji Ohsawa; Toshinori Otaka

    2018-01-01

    To respond to the high demand for high dynamic range imaging suitable for moving objects with few artifacts, we have developed a single-exposure dynamic range image sensor by introducing a triple-gain pixel and a low noise dual-gain readout circuit. The developed 3 μm pixel is capable of having three conversion gains. Introducing a new split-pinned photodiode structure, linear full well reaches 40 ke−. Readout noise under the highest pixel gain condition is 1 e− with a low noise readout circu...

  14. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  15. Factors limiting the sensitivity and dynamic range of a seismic system employing analog magnetic tape recording and a seismic amplifier with adjustable gain settings and several output levels

    Science.gov (United States)

    Eaton, Jerry P.; Van Schaack, John R.

    1977-01-01

    In the course of modernizing the low-speed-tape-recorder portable seismic systems and considering the possibilities for the design of a cassette-tape-recorder seismic refraction system, the factors that limit the sensitivity and dynamic range of such systems have been reviewed. These factors will first be stated briefly, and then their influence on systems such as the new 5-day-tape seismic system will be examined in more detail. To fix ideas, we shall assume that the system consists of the following elements: 1. A seismic sensor: usually a moving coil inertial seismometer with a period of about 1 second, a coil resistance of about 5000 ohms, and an effective motor constant of 1.0 V/cm/sec (across a 10K load terminating the seismometer sensitivity-and-damping-adjustment resistive network). 2. A seismic amplifier/voltage controlled oscillator unit made up of the following components: a) A fixed gain preamplifier with an input resistance of 10K and an internal noise level of 0.5 muVpp referred to the preamp input (0.1 Hz recording on separate tape tracks or modulated FM subcarriers for subsequent multiplexing and direct recording on tape in the California Network format. 3. An analog magnetic tape recorder: e.g. the PI 5100 (15/80 ips recording in the FM mode or in the direct mode with the 'broad-band' variant-of the Cal Net multiplex system, or 15/16 ips recording in the direct mode with the standard Cal Net multiplex system), or the Sony TC-126 cassette recorder operating in the direct record mode with the standard Cal Net multiplex system. 4. Appropriate magnetic tape playback equipment: e.g., the Bell and Howell 3700-B for the PI-5100 or the Sony TC 126 for its own tapes. 5. Appropriate discriminators (employing subtractive compensation, at least for the multiplexed systems) to restore the data signals to their original forms. 6. An A/D convertor to digitize the seismic signals for computer processing and/or a strip chart recorder (e.g., the Siemens Oscillomink

  16. Transonic Wind Tunnel Modernization for Experimental Investigation of Dynamic Stall in a Wide Range of Mach Numbers by Plasma Actuators with Combined Energy/Momentum Action

    Science.gov (United States)

    2015-01-02

    wind tunnel for the study of plasma based methods for the control of dynamic stall for helicopter rotor blades. The tunnel has a 3D positioning...SECURITY CLASSIFICATION OF: This equipment grant supported the design and construction of a subsonic variable speed wind tunnel for the study of...plasma based methods for the control of dynamic stall for helicopter rotor blades. The tunnel has a 3D positioning system and servomotor mounted below

  17. A 1.2-V 165-μW 0.29-mm² Multibit Sigma-Delta ADC for Hearing Aids Using Nonlinear DACs and With Over 91 dB Dynamic-Range

    DEFF Research Database (Denmark)

    Custódio, José R.; Goes, João; Paulino, Nuno

    2013-01-01

    This paper describes the design and experimental evaluation of a multibit Sigma-Delta (ΣΔ) modulator (ΣΔM) with enhanced dynamic range (DR) through the use of nonlinear digital-to-analog converters (DACs) in the feedback paths. This nonlinearity imposes a trade-off between DR and distortion, whic...

  18. Short-range intervortex interaction and interacting dynamics of half-quantized vortices in two-component Bose-Einstein condensates

    Science.gov (United States)

    Kasamatsu, Kenichi; Eto, Minoru; Nitta, Muneto

    2016-01-01

    We study the interaction and dynamics of two half-quantized vortices in two-component Bose-Einstein condensates. Using the Padé approximation for the vortex core profile, we calculate the intervortex potential, whose asymptotic form for a large distance has been derived by Eto et al. [Phys. Rev. A 83, 063603 (2011), 10.1103/PhysRevA.83.063603]. Through numerical simulations of the two-dimensional Gross-Pitaevskii equations, we reveal different kinds of dynamical trajectories of the vortices depending on the combinations of signs of circulations and the intercomponent density coupling. Under the adiabatic limit, we derive the equations of motion for the vortex coordinates, in which the motion is caused by the balance between Magnus force and the intervortex forces. The initial velocity of the vortex motion can be explained quantitatively by this point vortex approximation, but understanding the long-time behavior of the dynamics needs more consideration beyond our model.

  19. Energy transfers and spectral eddy viscosity in large-eddy simulations of homogeneous isotropic turbulence : Comparison of dynamic Smagorinsky and multiscale models over a range of discretizations

    NARCIS (Netherlands)

    Hughes, T.J.R.; Wells, G.N.; Wray, A.A.

    2004-01-01

    Energy transfers within large-eddy simulation (LES) and direct numerical simulation (DNS) grids are studied. The spectral eddy viscosity for conventional dynamic Smagorinsky and variational multiscale LES methods are compared with DNS results. Both models underestimate the DNS results for a very

  20. Reduced-order computational model in nonlinear structural dynamics for structures having numerous local elastic modes in the low-frequency range. Application to fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Batou, A., E-mail: anas.batou@univ-paris-est.fr [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallee (France); Soize, C., E-mail: christian.soize@univ-paris-est.fr [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallee (France); Brie, N., E-mail: nicolas.brie@edf.fr [EDF R and D, Département AMA, 1 avenue du général De Gaulle, 92140 Clamart (France)

    2013-09-15

    Highlights: • A ROM of a nonlinear dynamical structure is built with a global displacements basis. • The reduced order model of fuel assemblies is accurate and of very small size. • The shocks between grids of a row of seven fuel assemblies are computed. -- Abstract: We are interested in the construction of a reduced-order computational model for nonlinear complex dynamical structures which are characterized by the presence of numerous local elastic modes in the low-frequency band. This high modal density makes the use of the classical modal analysis method not suitable. Therefore the reduced-order computational model is constructed using a basis of a space of global displacements, which is constructed a priori and which allows the nonlinear dynamical response of the structure observed on the stiff part to be predicted with a good accuracy. The methodology is applied to a complex industrial structure which is made up of a row of seven fuel assemblies with possibility of collisions between grids and which is submitted to a seismic loading.

  1. Soil temperature and moisture dynamics after experimental irrigation on two contrasting soils on the Santa Rita Experimental Range: Implications for mesquite establishment

    Science.gov (United States)

    Nathan B. English; David G. Williams; Jake F. Weltzin

    2003-01-01

    We established a large-scale manipulative experiment in a semidesert grassland on the Santa Rita Experimental Range to determine how the recruitment and physiology of woody plants (Prosopis velutina Woot.) are affected by invasive grasses, seasonal precipitation regimes, and underlying soil characteristics. We established 72 2.8-m2 plots beneath six large rainout...

  2. Range doppler dynamic range considerations for dechirp on receive radar

    CSIR Research Space (South Africa)

    De Witt, JJ

    2008-10-01

    Full Text Available of (11) and the first three terms of (12). The maximum value of β is related to the available IF bandwidth (BIF in Hz) as max[β]=−2piBIF θp/∆fθ, if we let ∆fθ (= a/ωθ) denote the frequency span (in Hz) of one period of the phase error function... in OTHR,” 6th International Conference on Signal Processing, vol. 2, pp. 1461 – 1464, 26-30 Aug 2002. [7] G. Arfken and H. Weber, Mathematical Methods for Physicists, 5th ed. Harcourt/Academic Press, 2000. [8] X. Zeng, Q. Hu, J. He, Q. Tu, and X. Yu...

  3. Seasonal and Daily Dynamics of the CO2 Emission from Soils of Pinus koraiensis Forests in the South of the Sikhote-Alin Range

    Science.gov (United States)

    Ivanov, A. V.; Braun, M.; Tataurov, V. A.

    2018-03-01

    The presented study shows the results of measuring soil respiration in typical burozems (Dystric Cambisols) under mixed Korean pine-broadleaved forests in the southern part of the Primorskii (Far East) region of Russia growing under conditions of monsoon climate. The measurements were performed in 2014-2016 by the chamber method with the use of a portable infrared gas analyzer. Relative and total values of the CO2 efflux from the soil surface on four model plots were determined. The intensity of summer emission varied from 2.25 to 10.97 μmol/(m2 s), and the total CO2 efflux from the soils of four plots varied from 18.84 to 25.56 mol/m2. It is shown that a larger part of seasonal variability in the soil respiration is controlled by the soil temperature ( R 2 = 0.5-0.7); the soil water content also has a significant influence on the CO2 emission determining about 10% of its temporal variability. The daily dynamics of soil respiration under the old-age (200 yrs) forest have a significant relationship with the soil temperature ( R 2 = 0.51). The pyrogenic transformation of Pinus koraiensis forests into low-value oak forests is accompanied by an increase in the CO2 efflux from the soil.

  4. Uticaj povećanja dometa na dinamičku stabilnost artiljerijskih raketa sa olučastim krilima / Influence of range extension on dynamic stability for artillery rockets with wrap around fins

    Directory of Open Access Journals (Sweden)

    Danilo Ćuk

    2007-07-01

    Full Text Available U radu su prikazani efekti povećanja dometa artiljerijske rakete sa olučastim krilima na njenu dinamičku stabilnost. Totalni impuls raketnog motora, uvećan za 50% i let rakete kroz slojeve atmosfere sa malom gustinom vazduha povećavaju domet rakete za više od 75% od nominalnog dometa. Međutim, let rakete kroz razređeni vazduh proizvodi teškoće koje se odnose na dinamičku stabilnost. Male promene bočnog momenta indukovanog napadnim uglom i Magnusovog momenta mogu proizvesti nestabilnost kretanja i nedozvoljeni rast napadnog ugla. Određene su tolerancije bočnog momenta za osnovnu i poboljšanu varijantu rakete radi sprečavanja nestabilnog leta. Analiziran je, takođe uticaj povećanja dometa na verovatna odstupanja rakete po dometu i pravcu. / This paper presents the effects of the range extension of an artillery rocket with wrap around fins on its dynamic stability. The increased total impulse of the rocket engine for 50% and flight through the atmosphere layers with low air density extend the range for more than 75% of the nominal range. However, the flight of the unguided rocket through the rarefied air produces difficulties related to the dynamic stability. The small changes in the side moment which is induced by the angle of attack and Magnus moment of the improved rocket can produce instabilities in flight and increasement the angle of attack. The tolerances of the side moment were determined for both basic and improved type of the rocket in order to prevent instable flight. The influence of the range extension on the probable errors in range and cross-range was analyzed as well.

  5. Evaluating the influence of disturbance and climate on red spruce (Picea rubens Sarg.) community dynamics at its southern range margin using dendrochronology

    Science.gov (United States)

    Ribbons, R. R.

    2011-12-01

    Red spruce (Picea rubens Sarg.) populations experienced a synchronous range-wide decline in growth and vigor starting in the 1960's, which was likely caused by climate change or environmental disturbances (e.g., acid deposition); However, it is yet unknown if populations continue to decline or have recovered. In the context of global warming, red spruce is a species of concern because it is at its southern continuous range margin in Massachusetts. This study uses tree-ring data coupled with population data from permanent plots to quantify the status of red spruce in Massachusetts. Tree cores were extracted from red spruce and used to examine radial growth rates, determine a growth-climate relationship, and document disturbance events. Red spruce at these plots ranged from 90 to 184 years old, and comprised 15 to 27 m2/ha-1 basal area. Over the past 50 years, red spruce has decreased in density, basal area, and relative importance while red maple, yellow birch, and American beech have increased. Red spruce saplings persisted in some plots, but the sapling layer was comprised mostly of American beech or red maple. However, red spruce seedlings were common at red spruce dominant plots indicating that if favorable conditions occur, it could return to its more dominant position in the canopy. Dendroclimatological analyses show that red spruce is sensitive to both temperature and precipitation. Most sites are correlated with temperature, while only two forests were correlated to precipitation. The general temperature response of the red spruce studied was positively correlated with winter temperatures while the general precipitation response was negatively correlated with precipitation. Temporal analysis of the climate-growth response indicates that red spruce here have not had a temporally-stable, climate-growth relationship. Prior to 1960, radial growth was positively correlated with temperatures from November of the previous growing season to January of the current

  6. Fine-scale genetic breaks driven by historical range dynamics and ongoing density-barrier effects in the estuarine seaweed Fucus ceranoides L.

    Directory of Open Access Journals (Sweden)

    Neiva João

    2012-06-01

    Full Text Available Abstract Background Factors promoting the emergence of sharp phylogeographic breaks include restricted dispersal, habitat discontinuity, physical barriers, disruptive selection, mating incompatibility, genetic surfing and secondary contact. Disentangling the role of each in any particular system can be difficult, especially when species are evenly distributed across transition zones and dispersal barriers are not evident. The estuarine seaweed Fucus ceranoides provides a good example of highly differentiated populations along its most persistent distributional range at the present rear edge of the species distribution, in NW Iberia. Intrinsic dispersal restrictions are obvious in this species, but have not prevented F. ceranoides from vastly expanding its range northwards following the last glaciation, implying that additional factors are responsible for the lack of connectivity between neighbouring southern populations. In this study we analyze 22 consecutive populations of F. ceranoides along NW Iberia to investigate the processes generating and maintaining the observed high levels of regional genetic divergence. Results Variation at seven microsatellite loci and at mtDNA spacer sequences was concordant in revealing that Iberian F. ceranoides is composed of three divergent genetic clusters displaying nearly disjunct geographical distributions. Structure and AFC analyses detected two populations with an admixed nuclear background. Haplotypic diversity was high in the W sector and very low in the N sector. Within each genetic cluster, population structure was also pervasive, although shallower. Conclusions The deep divergence between sectors coupled with the lack of support for a role of oceanographic barriers in defining the location of breaks suggested 1 that the parapatric genetic sectors result from the regional reassembly of formerly vicariant sub-populations, and 2 that the genetic discontinuities at secondary contact zones (and elsewhere

  7. Rotation of Magnetization Derived from Brownian Relaxation in Magnetic Fluids of Different Viscosity Evaluated by Dynamic Hysteresis Measurements over a Wide Frequency Range.

    Science.gov (United States)

    Ota, Satoshi; Kitaguchi, Ryoichi; Takeda, Ryoji; Yamada, Tsutomu; Takemura, Yasushi

    2016-09-10

    The dependence of magnetic relaxation on particle parameters, such as the size and anisotropy, has been conventionally discussed. In addition, the influences of external conditions, such as the intensity and frequency of the applied field, the surrounding viscosity, and the temperature on the magnetic relaxation have been researched. According to one of the basic theories regarding magnetic relaxation, the faster type of relaxation dominates the process. However, in this study, we reveal that Brownian and Néel relaxations coexist and that Brownian relaxation can occur after Néel relaxation despite having a longer relaxation time. To understand the mechanisms of Brownian rotation, alternating current (AC) hysteresis loops were measured in magnetic fluids of different viscosities. These loops conveyed the amplitude and phase delay of the magnetization. In addition, the intrinsic loss power (ILP) was calculated using the area of the AC hysteresis loops. The ILP also showed the magnetization response regarding the magnetic relaxation over a wide frequency range. To develop biomedical applications of magnetic nanoparticles, such as hyperthermia and magnetic particle imaging, it is necessary to understand the mechanisms of magnetic relaxation.

  8. Rotation of Magnetization Derived from Brownian Relaxation in Magnetic Fluids of Different Viscosity Evaluated by Dynamic Hysteresis Measurements over a Wide Frequency Range

    Directory of Open Access Journals (Sweden)

    Satoshi Ota

    2016-09-01

    Full Text Available The dependence of magnetic relaxation on particle parameters, such as the size and anisotropy, has been conventionally discussed. In addition, the influences of external conditions, such as the intensity and frequency of the applied field, the surrounding viscosity, and the temperature on the magnetic relaxation have been researched. According to one of the basic theories regarding magnetic relaxation, the faster type of relaxation dominates the process. However, in this study, we reveal that Brownian and Néel relaxations coexist and that Brownian relaxation can occur after Néel relaxation despite having a longer relaxation time. To understand the mechanisms of Brownian rotation, alternating current (AC hysteresis loops were measured in magnetic fluids of different viscosities. These loops conveyed the amplitude and phase delay of the magnetization. In addition, the intrinsic loss power (ILP was calculated using the area of the AC hysteresis loops. The ILP also showed the magnetization response regarding the magnetic relaxation over a wide frequency range. To develop biomedical applications of magnetic nanoparticles, such as hyperthermia and magnetic particle imaging, it is necessary to understand the mechanisms of magnetic relaxation.

  9. Global compensation of long-range beam-beam effects with octupole magnets: dynamic aperture simulations for the HL-LHC case and possible usage in LHC and FCC.

    CERN Document Server

    Barranco Garcia, Javier; CERN. Geneva. ATS Department

    2017-01-01

    The Large Hadron Collider has shown with various experimental verifications that one of the main limitations to the collider performance and to a possible upgrade can come from the long-range beam-beam effects which will define the operational parameters (intensities and emittances) and machine set-up (crossing angles and the minimum beta function at the interaction points). The High Luminosity project aims at very high intensities and will therefore need much larger separations to keep the long range effects weak. In the past several studies of possible active compensators have been carried out and experimental studies are planned to explore such schemes in the LHC. In this note we show the feasibility of using octupole magnets to compensate the effects of long range beam-beam interactions by use of dynamical aperture simulations. A prove of principle of such a compensation scheme is shown for the HL-LHC optics. Preliminary studies for the LHC optics ATS and standard are also presented pointing to the import...

  10. A 1.2-V 165-μW 0.29-mm2 multibit Sigma-Delta ADC for hearing aids using nonlinear DACs and with over 91 dB dynamic-range.

    Science.gov (United States)

    Custodio, José R; Goes, João; Paulino, Nuno; Oliveira, João P; Bruun, Erik

    2013-06-01

    This paper describes the design and experimental evaluation of a multibit Sigma-Delta (ΣΔ) modulator (ΣΔM) with enhanced dynamic range (DR) through the use of nonlinear digital-to-analog converters (DACs) in the feedback paths. This nonlinearity imposes a trade-off between DR and distortion, which is well suited to the intended hearing aid application. The modulator proposed here uses a fully-differential self-biased amplifier and a 4-bit quantizer based on fully dynamic comparators employing MOS parametric pre-amplification to improve both energy and area efficiencies. A test chip was fabricated in a 130 nm digital CMOS technology, which includes the proposed modulator with nonlinear DACs and a modulator with conventional linear DACs, for comparison purposes. The measured results show that the ΣΔM using nonlinear DACs achieves an enhancement of the DR around 8.4 dB (to 91.4 dB). Power dissipation and silicon area are about the same for the two cases. The performance achieved is comparable to that of the best reported multibit ΣΔ ADCs, with the advantage of occupying less silicon area (7.5 times lower area when compared with the most energy efficient ΣΔM).

  11. Cold and ultracold dynamics of the barrierless D{sup +} + H{sub 2} reaction: Quantum reactive calculations for ∼R{sup −4} long range interaction potentials

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Manuel, E-mail: manuel.lara@uam.es [Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Jambrina, P. G.; Aoiz, F. J. [Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid (Spain); Launay, J.-M. [Institut de Physique de Rennes, UMR CNRS 6251, Université de Rennes I, F-35042 Rennes (France)

    2015-11-28

    Quantum reactive and elastic cross sections and rate coefficients have been calculated for D{sup +} + H{sub 2} (v = 0, j = 0) collisions in the energy range from 10{sup −8} K (deep ultracold regime), where only one partial wave is open, to 150 K (Langevin regime) where many of them contribute. In systems involving ions, the ∼R{sup −4} behavior extends the interaction up to extremely long distances, requiring a special treatment. To this purpose, we have used a modified version of the hyperspherical quantum reactive scattering method, which allows the propagations up to distances of 10{sup 5} a{sub 0} needed to converge the elastic cross sections. Interpolation procedures are also proposed which may reduce the cost of exact dynamical calculations at such low energies. Calculations have been carried out on the PES by Velilla et al. [J. Chem. Phys. 129, 084307 (2008)] which accurately reproduces the long range interactions. Results on its prequel, the PES by Aguado et al. [J. Chem. Phys. 112, 1240 (2000)], are also shown in order to emphasize the significance of the inclusion of the long range interactions. The calculated reaction rate coefficient changes less than one order of magnitude in a collision energy range of ten orders of magnitude, and it is found in very good agreement with the available experimental data in the region where they exist (10-100 K). State-to-state reaction probabilities are also provided which show that for each partial wave, the distribution of HD final states remains essentially constant below 1 K.

  12. Thermodynamical and structural properties of solid surfaces in the high temperature range by molecular dynamics solution: evidence for a roughening transition on the F.C.C. {110} surface

    International Nuclear Information System (INIS)

    Rosato, Vittorio

    1986-01-01

    We have studied by Molecular Dynamics simulation the thermodynamical and structural properties of the {110} solid Argon surface as a function of temperature up to T m . The following results have been obtained: 1) the Arrhenius plot indicates that for T> 0.7 T m the defect creation becomes a nearly athermal process. The measured surface diffusion coefficients are very high and are comparable with those observed in the liquid state. 2) the long range order is preserved at least up to T= 0.94 T m . The thermal disorder is related to the onset of a roughening transition on that surface at T ≅ 0.7 T m . Surface layers are not melted in the whole range of temperature we have studied. Furthermore we have investigated the influence of constraints on the surface structure for the same model system previously used at T = 0.48 T m . We have shown that both temperature and constraints induce disorder on surface: for constraints corresponding to elastic deformations of -5 pc applied along the dense axis {110}, the surface structure results to be very similar to that obtained, without constraints, at a higher temperature (T = 0.68 T m ). The implications of our bindings in several areas of Materials Science are briefly discussed. (author) [fr

  13. GPS test range mission planning

    Science.gov (United States)

    Roberts, Iris P.; Hancock, Thomas P.

    The principal features of the Test Range User Mission Planner (TRUMP), a PC-resident tool designed to aid in deploying and utilizing GPS-based test range assets, are reviewed. TRUMP features time history plots of time-space-position information (TSPI); performance based on a dynamic GPS/inertial system simulation; time history plots of TSPI data link connectivity; digital terrain elevation data maps with user-defined cultural features; and two-dimensional coverage plots of ground-based test range assets. Some functions to be added during the next development phase are discussed.

  14. The Ranging and Nanosatellite Guidance Experiment (RANGE)

    OpenAIRE

    Gunter, Brian C.; Davis, Byron; Lightsey, Glenn; Braun, Robert D.

    2016-01-01

    The Ranging And Nanosatellite Guidance Experiment (RANGE) cubesat mission was recently selected for a flight opportunity as part of the Skybox University Cubesat Partnership, with a tentative launch date scheduled for 2016. The RANGE mission involves two 1.5U cubesats flying in a leader-follower formation with the goal of improving the relative and absolute positioning capabilities of nanosatellites. The satellites' absolute positions will be tracked using GPS receivers synchronized with mini...

  15. Impact of natural climate change and historical land use on vegetation cover and geomorphological process dynamics in the Serra dos Órgãos mountain range in Rio de Janeiro State, Brazil

    Science.gov (United States)

    Nehren, U.; Sattler, D.; Heinrich, J.

    2010-03-01

    The Serra dos Órgãos mountain range in the hinterland of Rio de Janeiro contains extensive remnants of the Atlantic Forest (Mata Atlântica) biome, which once covered about 1.5 million km² from Northeast to South Brazil and further inland to Paraguay and Argentina. As a result of historical deforestation and recent land use intensification processes today only 5 to 8% of the original Atlantic Forest remains. Despite the dramatic habitat loss and a high degree of forest fragmentation, the remnants are among the Earth’s most diverse habitats in terms of species richness. Furthermore, they are characterized by a high level of endemism. Therefore, the biome is considered a "hotspot of biodiversity". In the last years many efforts have been taken to investigate the Mata Atlântica biome in different spatial and time scales and from different scientific perspectives. We are working in the Atlantic Forest of Rio de Janeiro since 2004 and focus in our research particularly on Quaternary landscape evolution and landscape history. By means of landscape and soil archives we reconstruct changes in the landscape system, which are mainly the result of Quaternary climate variability, young tectonic uplift and human impact. The findings throw light on paleoecological conditions in the Late Quaternary and the impact of pre-colonial and colonial land use practices on these landscapes. In this context, a main focus is set on climate and human-driven changes of the vegetation cover and its consequences for the geomorphological process dynamics, in particular erosion and sedimentation processes. Research methods include geomorphological field studies, interpretation of satellite images, physical and chemical sediment and soil analyses as well as relative and absolute dating (Feo/Fed ratio and 14C dating). For the Late Quaternary landscape evolution, the findings are compared with results from paleoclimatic and paloecological investigations in Southeast and South Brazil using other

  16. Non-destructive examination of TRU waste in low and high density boxes and drums, using high energy real time radioscopy (HE-RTR) and wide dynamic range imaging - 59302

    International Nuclear Information System (INIS)

    Halliwell, Stephen

    2012-01-01

    Document available in abstract form only. Full text of publication follows: The Waste Isolation Pilot Plant (WIPP), the cornerstone of the Department of Energy's nuclear waste cleanup effort, is designed to permanently dispose of transuranic (TRU) radioactive waste. Real time radioscopy (RTR) using x-ray energies of up to 450 keV, has been used extensively for the non-destructive examination (NDE) part of the characterization and certification of waste drums and low density waste boxes, prior to shipment to WIPP. However, to characterize drums and boxes containing a mixture of both low and high density waste, x-ray energies of up to 6 MeV, together with an x-ray imaging system having a wide dynamic range, are required. The system, including the high energy vault, is required to be stand-alone, weatherproof and re-locatable, and must be fully compliant with ANSI.N43.3, classified as an exempt shielded facility for x-ray energies up to 6 MeV. This paper describes the design, build and operation of the new generation of high energy RTR systems now being used in the characterization of waste destined for disposal at WIPP. Importance of this work. Characterization of TRU waste in boxes and drums by non-destructive examination reduces the need to open the containment and to visually examine the waste. The immediate benefits are a reduction in risk of operator dose uptake, a reduction in the generation of additional waste, and the saving of time and cost within the process. (author)

  17. Dynamical systems

    CERN Document Server

    Sternberg, Shlomo

    2010-01-01

    Celebrated mathematician Shlomo Sternberg, a pioneer in the field of dynamical systems, created this modern one-semester introduction to the subject for his classes at Harvard University. Its wide-ranging treatment covers one-dimensional dynamics, differential equations, random walks, iterated function systems, symbolic dynamics, and Markov chains. Supplementary materials offer a variety of online components, including PowerPoint lecture slides for professors and MATLAB exercises.""Even though there are many dynamical systems books on the market, this book is bound to become a classic. The the

  18. Telemetry-Based Ranging

    Science.gov (United States)

    Hamkins, Jon; Vilnrotter, Victor A.; Andrews, Kenneth S.; Shambayati, Shervin

    2011-01-01

    A telemetry-based ranging scheme was developed in which the downlink ranging signal is eliminated, and the range is computed directly from the downlink telemetry signal. This is the first Deep Space Network (DSN) ranging technology that does not require the spacecraft to transmit a separate ranging signal. By contrast, the evolutionary ranging techniques used over the years by NASA missions, including sequential ranging (transmission of a sequence of sinusoids) and PN-ranging (transmission of a pseudo-noise sequence) whether regenerative (spacecraft acquires, then regenerates and retransmits a noise-free ranging signal) or transparent (spacecraft feeds the noisy demodulated uplink ranging signal into the downlink phase modulator) relied on spacecraft power and bandwidth to transmit an explicit ranging signal. The state of the art in ranging is described in an emerging CCSDS (Consultative Committee for Space Data Systems) standard, in which a pseudo-noise (PN) sequence is transmitted from the ground to the spacecraft, acquired onboard, and the PN sequence is coherently retransmitted back to the ground, where a delay measurement is made between the uplink and downlink signals. In this work, the telemetry signal is aligned with the uplink PN code epoch. The ground station computes the delay between the uplink signal transmission and the received downlink telemetry. Such a computation is feasible because symbol synchronizability is already an integral part of the telemetry design. Under existing technology, the telemetry signal cannot be used for ranging because its arrival-time information is not coherent with any Earth reference signal. By introducing this coherence, and performing joint telemetry detection and arrival-time estimation on the ground, a high-rate telemetry signal can provide all the precision necessary for spacecraft ranging.

  19. Dryden Aeronautical Test Range

    Data.gov (United States)

    Federal Laboratory Consortium — Recently redesignated to honor Dr. Hugh L. Dryden, NASA's Dryden Aeronautical Test Range (DATR) supports aerospace flight research and technology integration, space...

  20. Measurements of regional cerebral blood flow (rCBF) using dynamic single-photon emission computed tomography (DSPECT): Definition of a generally acceptable normal range and follow-up checks after extracranial bypass surgery

    International Nuclear Information System (INIS)

    Kreisig, T.

    1986-01-01

    The usefulness of dynamic single-photon emission computed tomography was evaluated in 50 volunteers with unobtrusive cerebral findings, who were to provide the relevant standard values. It was found that the values measured were easily reproducible. Measurements in patients showing cerebrovascular disease that were carried out before and after extracranial bypass surgery did mostly not suggest any perceivable improvement of cerebral blood flow. In isolated cases the cerebral reserve was influenced favourably, as judged from measurements after administration of acetazolamide. (MBC) [de

  1. On Range of Skill

    DEFF Research Database (Denmark)

    Hansen, Thomas Dueholm; Miltersen, Peter Bro; Sørensen, Troels Bjerre

    2008-01-01

    size (and doubly exponential in its depth). We also provide techniques that yield concrete bounds for unbalanced game trees and apply these to estimate the Range of Skill of Tic-Tac-Toe and Heads-Up Limit Texas Hold'em Poker. In particular, we show that the Range of Skill of Tic-Tac-Toe is more than...

  2. Home range and travels

    Science.gov (United States)

    Stickel, L.F.; King, John A.

    1968-01-01

    The concept of home range was expressed by Seton (1909) in the term 'home region,' which Burr (1940, 1943) clarified with a definition of home range and exemplified in a definitive study of Peromyscus in the field. Burt pointed out the ever-changing characteristics of home-range area and the consequent absence of boundaries in the usual sense--a finding verified by investigators thereafter. In the studies summarized in this paper, sizes of home ranges of Peromyscus varied within two magnitudes, approximately from 0.1 acre to ten acres, in 34 studies conducted in a variety of habitats from the seaside dunes of Florida to the Alaskan forests. Variation in sizes of home ranges was correlated with both environmental and physiological factors; with habitat it was conspicuous, both in the same and different regions. Food supply also was related to size of home range, both seasonally and in relation to habitat. Home ranges generally were smallest in winter and largest in spring, at the onset of the breeding season. Activity and size also were affected by changes in weather. Activity was least when temperatures were low and nights were bright. Effects of rainfall were variable. Sizes varied according to sex and age; young mice remained in the parents' range until they approached maturity, when they began to travel more widely. Adult males commonly had larger home ranges than females, although there were a number of exceptions. An inverse relationship between population density and size of home range was shown in several studies and probably is the usual relationship. A basic need for activity and exploration also appeared to influence size of home range. Behavior within the home range was discussed in terms of travel patterns, travels in relation to home sites and refuges, territory, and stability of size of home range. Travels within the home range consisted of repeated use of well-worn trails to sites of food, shelter, and refuge, plus more random exploratory travels

  3. Soliton microcomb range measurement

    Science.gov (United States)

    Suh, Myoung-Gyun; Vahala, Kerry J.

    2018-02-01

    Light detection and ranging systems are used in many engineering and environmental sensing applications. Their relatively large size and cost, however, tend to be prohibitive for general use in autonomous vehicles and drones. Suh and Vahala and Trocha et al. show that optical frequency combs generated by microresonator devices can be used for precision ranging and the tracking of fast-moving objects. The compact size of the microresonators could broaden the scope for widespread applications, providing a platform for miniaturized laser ranging systems suitable for photonic integration.

  4. Antenna Pattern Range (APR)

    Data.gov (United States)

    Federal Laboratory Consortium — TheAntenna Pattern Range (APR)features a non-metallic arch with a trolley to move the transmit antenna from the horizon to zenith. At the center of the ground plane,...

  5. Atlantic Test Range (ATR)

    Data.gov (United States)

    Federal Laboratory Consortium — ATR controls fully-instrumented and integrated test ranges that provide full-service support for cradle-to-grave testing. Airspace and surface target areas are used...

  6. Range Selection and Median

    DEFF Research Database (Denmark)

    Jørgensen, Allan Grønlund; Larsen, Kasper Green

    2011-01-01

    and several natural special cases thereof. The rst special case is known as range median, which arises when k is xed to b(j 􀀀 i + 1)=2c. The second case, denoted prex selection, arises when i is xed to 0. Finally, we also consider the bounded rank prex selection problem and the xed rank range......Range selection is the problem of preprocessing an input array A of n unique integers, such that given a query (i; j; k), one can report the k'th smallest integer in the subarray A[i];A[i+1]; : : : ;A[j]. In this paper we consider static data structures in the word-RAM for range selection...... selection problem. In the former, data structures must support prex selection queries under the assumption that k for some value n given at construction time, while in the latter, data structures must support range selection queries where k is xed beforehand for all queries. We prove cell probe lower bounds...

  7. A STRUCTURED APPROACH TO VOICE RANGE PROFILE (PHONETOGRAM) ANALYSIS

    NARCIS (Netherlands)

    SULTER, AM; WIT, HP; SCHUTTE, HK; MILLER, DG

    1994-01-01

    A new method to analyze voice range profiles (phonetograms) is described. The structured analysis is based on quantitatively determining the features: shape, area, and ''speaking range'' dynamics, without distorting the shape of phonetograms. The parameter sets describing these features are

  8. Substring Range Reporting

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li

    2011-01-01

    We revisit various string indexing problems with range reporting features, namely, position-restricted substring searching, indexing substrings with gaps, and indexing substrings with intervals. We obtain the following main results. – We give efficient reductions for each of the above problems...... to a new problem, which we call substring range reporting. Hence, we unify the previous work by showing that we may restrict our attention to a single problem rather than studying each of the above problems individually. – We show how to solve substring range reporting with optimal query time and little...... space. Combined with our reductions this leads to significantly improved time-space trade-offs for the above problems. In particular, for each problem we obtain the first solutions with optimal time query and O(n logO(1) n) space, where n is the length of the indexed string. Our bounds for substring...

  9. Substring Range Reporting

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li

    2014-01-01

    We revisit various string indexing problems with range reporting features, namely, position-restricted substring searching, indexing substrings with gaps, and indexing substrings with intervals. We obtain the following main results. We give efficient reductions for each of the above problems...... to a new problem, which we call substring range reporting. Hence, we unify the previous work by showing that we may restrict our attention to a single problem rather than studying each of the above problems individually. We show how to solve substring range reporting with optimal query time and little...... space. Combined with our reductions this leads to significantly improved time-space trade-offs for the above problems. In particular, for each problem we obtain the first solutions with optimal time query and O(nlog O(1) n) space, where n is the length of the indexed string. We show that our techniques...

  10. Range-clustering queries

    DEFF Research Database (Denmark)

    Abrahamsen, Mikkel; de Berg, Mark; Buchin, Kevin

    2017-01-01

    an optimal k-clustering for S P ∩ Q. We obtain the following results. • We present a general method to compute a (1 + ϵ)-approximation to a range-clustering query, where ϵ > 0 is a parameter that can be specified as part of the query. Our method applies to a large class of clustering problems, including k...

  11. Agriculture, forestry, range resources

    Science.gov (United States)

    Macdonald, R. B.

    1974-01-01

    The necessary elements to perform global inventories of agriculture, forestry, and range resources are being brought together through the use of satellites, sensors, computers, mathematics, and phenomenology. Results of ERTS-1 applications in these areas, as well as soil mapping, are described.

  12. Space-Based Range

    Science.gov (United States)

    2008-01-01

    Space-Based Range (SBR), previously known as Space-Based Telemetry and Range Safety (STARS), is a multicenter NASA proof-of-concept project to determine if space-based communications using NASA's Tracking and Data Relay Satellite System (TDRSS) can support the Range Safety functions of acquiring tracking data and generating flight termination signals, while also providing broadband Range User data such as voice, video, and vehicle/payload data. There was a successful test of the Range Safety system at Wallops Flight Facility (WFF) on December 20, 2005, on a two-stage Terrier-Orion spin-stabilized sounding rocket. SBR transmitted GPS tracking data and maintained links with two TDRSS satellites simultaneously during the 10-min flight. The payload section deployed a parachute, landed in the Atlantic Ocean about 90 miles downrange from the launch site, and was successfully recovered. During the Terrier-Orion tests flights, more than 99 percent of all forward commands and more than 95 percent of all return frames were successfully received and processed. The time latency necessary for a command to travel from WFF over landlines to White Sands Complex and then to the vehicle via TDRSS, be processed onboard, and then be sent back to WFF was between 1.0 s and 1.1 s. The forward-link margins for TDRS-10 (TDRS East [TDE]) were 11 dB to 12 dB plus or minus 2 dB, and for TDRS-4 (TDRS Spare [TDS]) were 9 dB to 10 dB plus or minus 1.5 dB. The return-link margins for both TDE and TDS were 6 dB to 8 dB plus or minus 3 dB. There were 11 flights on an F-15B at Dryden Flight Research Center (DFRC) between November 2006 and February 2007. The Range User system tested a 184-element TDRSS Ku-band (15 GHz) phased-array antenna with data rates of 5 Mbps and 10 Mbps. This data was a combination of black-and-white cockpit video, Range Safety tracking and transceiver data, and aircraft and antenna controller data streams. IP data formatting was used.

  13. Comparison of short-range-order in liquid- and rotator-phase states of a simple molecular liquid: A reverse Monte Carlo and molecular dynamics analysis of neutron diffraction data

    International Nuclear Information System (INIS)

    Pardo, Luis Carlos; Tamarit, Josep Lluis; Veglio, Nestor; Bermejo, Francisco Javier; Cuello, Gabriel Julio

    2007-01-01

    The short-range order (SRO) correlations in liquid- and rotator-phase states of carbon tetrachloride are revisited here. The correlation of some angular magnitudes is used to evaluate the positional and orientational correlations in the liquid as well as in the rotator phase. The results show significant similitudes in the relative position of the molecules surrounding a central one but striking differences in their relative orientations, which could explain the changes in SRO between the two phases and the puzzling behavior of the local density in the liquid and rotator phases

  14. Hendra Virus Infection Dynamics in the Grey-Headed Flying Fox (Pteropus poliocephalus) at the Southern-Most Extent of Its Range: Further Evidence This Species Does Not Readily Transmit the Virus to Horses.

    Science.gov (United States)

    Burroughs, A L; Durr, P A; Boyd, V; Graham, K; White, J R; Todd, S; Barr, J; Smith, I; Baverstock, G; Meers, J; Crameri, G; Wang, L-F

    2016-01-01

    Hendra virus (HeV) is an important emergent virus in Australia known to infect horses and humans in certain regions of the east coast. Whilst pteropid bats ("flying foxes") are considered the natural reservoir of HeV, which of the four mainland species is the principal reservoir has been a source of ongoing debate, particularly as shared roosting is common. To help resolve this, we sampled a colony consisting of just one of these species, the grey-headed flying fox, (Pteropus poliocephalus), at the southernmost extent of its range. Using the pooled urine sampling technique at approximately weekly intervals over a two year period, we determined the prevalence of HeV and related paramyxoviruses using a novel multiplex (Luminex) platform. Whilst all the pooled urine samples were negative for HeV nucleic acid, we successfully identified four other paramyxoviruses, including Cedar virus; a henipavirus closely related to HeV. Collection of serum from individually caught bats from the colony showed that antibodies to HeV, as estimated by a serological Luminex assay, were present in between 14.6% and 44.5% of animals. The wide range of the estimate reflects uncertainties in interpreting intermediate results. Interpreting the study in the context of HeV studies from states to the north, we add support for an arising consensus that it is the black flying fox and not the grey-headed flying fox that is the principal source of HeV in spillover events to horses.

  15. Range Flight Safety Requirements

    Science.gov (United States)

    Loftin, Charles E.; Hudson, Sandra M.

    2018-01-01

    The purpose of this NASA Technical Standard is to provide the technical requirements for the NPR 8715.5, Range Flight Safety Program, in regards to protection of the public, the NASA workforce, and property as it pertains to risk analysis, Flight Safety Systems (FSS), and range flight operations. This standard is approved for use by NASA Headquarters and NASA Centers, including Component Facilities and Technical and Service Support Centers, and may be cited in contract, program, and other Agency documents as a technical requirement. This standard may also apply to the Jet Propulsion Laboratory or to other contractors, grant recipients, or parties to agreements to the extent specified or referenced in their contracts, grants, or agreements, when these organizations conduct or participate in missions that involve range flight operations as defined by NPR 8715.5.1.2.2 In this standard, all mandatory actions (i.e., requirements) are denoted by statements containing the term “shall.”1.3 TailoringTailoring of this standard for application to a specific program or project shall be formally documented as part of program or project requirements and approved by the responsible Technical Authority in accordance with NPR 8715.3, NASA General Safety Program Requirements.

  16. Hendra Virus Infection Dynamics in the Grey-Headed Flying Fox (Pteropus poliocephalus at the Southern-Most Extent of Its Range: Further Evidence This Species Does Not Readily Transmit the Virus to Horses.

    Directory of Open Access Journals (Sweden)

    A L Burroughs

    Full Text Available Hendra virus (HeV is an important emergent virus in Australia known to infect horses and humans in certain regions of the east coast. Whilst pteropid bats ("flying foxes" are considered the natural reservoir of HeV, which of the four mainland species is the principal reservoir has been a source of ongoing debate, particularly as shared roosting is common. To help resolve this, we sampled a colony consisting of just one of these species, the grey-headed flying fox, (Pteropus poliocephalus, at the southernmost extent of its range. Using the pooled urine sampling technique at approximately weekly intervals over a two year period, we determined the prevalence of HeV and related paramyxoviruses using a novel multiplex (Luminex platform. Whilst all the pooled urine samples were negative for HeV nucleic acid, we successfully identified four other paramyxoviruses, including Cedar virus; a henipavirus closely related to HeV. Collection of serum from individually caught bats from the colony showed that antibodies to HeV, as estimated by a serological Luminex assay, were present in between 14.6% and 44.5% of animals. The wide range of the estimate reflects uncertainties in interpreting intermediate results. Interpreting the study in the context of HeV studies from states to the north, we add support for an arising consensus that it is the black flying fox and not the grey-headed flying fox that is the principal source of HeV in spillover events to horses.

  17. Dynamics of 4-oxo-TEMPO-d16-15N nitroxide-propylene glycol system studied by ESR and ESE in liquid and glassy state in temperature range 10-295 K

    Science.gov (United States)

    Goslar, Janina; Hoffmann, Stanislaw K.; Lijewski, Stefan

    2016-08-01

    ESR spectra and electron spin relaxation of nitroxide radical in 4-oxo-TEMPO-d16-15N in propylene glycol were studied at X-band in the temperature range 10-295 K. The spin-lattice relaxation in the liquid viscous state determined from the resonance line shape is governed by three mechanisms occurring during isotropic molecular reorientations. In the glassy state below 200 K the spin-lattice relaxation, phase relaxation and electron spin echo envelope modulations (ESEEM) were studied by pulse spin echo technique using 2-pulse and 3-pulse induced signals. Electron spin-lattice relaxation is governed by a single non-phonon relaxation process produced by localized oscillators of energy 76 cm-1. Electron spin dephasing is dominated by a molecular motion producing a resonance-type peak in the temperature dependence of the dephasing rate around 120 K. The origin of the peak is discussed and a simple method for the peak shape analysis is proposed, which gives the activation energy of a thermally activated motion Ea = 7.8 kJ/mol and correlation time τ0 = 10-8 s. The spin echo amplitude is strongly modulated and FT spectrum contains a doublet of lines centered around the 2D nuclei Zeeman frequency. The splitting into the doublet is discussed as due to a weak hyperfine coupling of nitroxide unpaired electron with deuterium of reorienting CD3 groups.

  18. Simulation of Dry Matter Productivity and Water Dynamics in a Chilean Patagonian Range Simulación de la Productividad de Materia Seca y Dinámica del Agua en Praderas de la Patagonia Chilena

    Directory of Open Access Journals (Sweden)

    Giorgio Castellaro G

    2010-09-01

    Full Text Available This paper describes a simulation model combining the main components of water balance and growth of perennial grassland steppe in Chilean Patagonia, to estimate long-term annual production (Yr, kg ha-1 and sheep carrying capacity (GC, sheep equivalent [EO] ha-1. The model is based on climate-water balance relationships, where the basic process is evapotranspiration. The model calculates Yr depending on the accumulation of transpiration and the water use efficiency from the time of growth initiation until the grassland accumulates the maximum amount of dry matter (DM. Depending on Yr, the DM requirement of EO, the proper use factor of grassland and a slope correction factor, a range site GC is calculated. Simulations were performed using actual climate data sets of eight growing seasons at Kampenaike (52º41' S; 70°54'W; 12 m.a.s.l. and a long-term simulation in the same location, using a stochastic weather variables generator. Through the model it was possible to estimate the water loss associated with the components of water balance and estimate the restriction imposed by water deficit on Yr. By simulating many years, it was possible to establish a normal distribution of GC with 0.629 EO ha-1 yr-1, associated with 80% probability of being exceeded, which is lower than values reported in field assessments. This method calculates GC with a conservational approach, taking into account soil and climatic variability in semiarid ecosystems.Se describe un modelo de simulación para pastizales esteparios de la Patagonia chilena, que estima a largo plazo los principales componentes del balance hídrico, la producción anual de MS (Yr, kg ha-1 y la capacidad de carga ovina (GC, equivalente ovino [EO] ha-1 de éstos. El modelo se basa en la relación clima-balance hídrico, siendo el proceso básico la evapotranspiración. Yr es función de la acumulación de transpiración durante la temporada de crecimiento y de la eficiencia del uso del agua. La GC

  19. Neutron range spectrometer

    Science.gov (United States)

    Manglos, Stephen H.

    1989-06-06

    A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are collimnated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

  20. Capacitive Proximity Sensor Has Longer Range

    Science.gov (United States)

    Vranish, John M.

    1992-01-01

    Capacitive proximity sensor on robot arm detects nearby object via capacitive effect of object on frequency of oscillator. Sensing element part of oscillator circuit operating at about 20 kHz. Total capacitance between sensing element and ground constitutes tuning capacitance of oscillator. Sensor circuit includes shield driven by replica of alternating voltage applied to sensing element. Driven shield concentrates sensing electrostatic field in exterior region to enhance sensitivity to object. Sensitivity and dynamic range has corresponding 12-to-1 improvement.

  1. Forest dynamics.

    Science.gov (United States)

    Frelich, Lee

    2016-01-01

    Forest dynamics encompass changes in stand structure, species composition, and species interactions with disturbance and environment over a range of spatial and temporal scales. For convenience, spatial scale is defined as individual tree, neighborhood, stand, and landscape. Whether a given canopy-leveling disturbance will initiate a sequence of development in structure with little change in composition or initiate an episode of succession depends on a match or mismatch, respectively, with traits of the dominant tree species that allow the species to survive disturbance. When these match, certain species-disturbance type combinations lock in a pattern of stand and landscape dynamics that can persist for several generations of trees; thus, dominant tree species regulate, as well as respond to, disturbance. A complex interaction among tree species, neighborhood effects, disturbance type and severity, landform, and soils determines how stands of differing composition form and the mosaic of stands that compose the landscape. Neighborhood effects (e.g., serotinous seed rain, sprouting, shading, leaf-litter chemistry, and leaf-litter physical properties) operate at small spatial extents of the individual tree and its neighbors but play a central role in forest dynamics by contributing to patch formation at stand scales and dynamics of the entire landscape. Dominance by tree species with neutral to negative neighborhood effects leads to unstable landscape dynamics in disturbance-prone regions, wherein most stands are undergoing succession; stability can only occur under very low-severity disturbance regimes. Dominance by species with positive effects leads to stable landscape dynamics wherein only a small proportion of stands undergo succession at any one time. Positive neighborhood effects are common in temperate and boreal zones, whereas negative effects are more common in tropical climates. Landscapes with positive dynamics have alternate categories of dynamics

  2. Dynamic-range tests for a gamma-ray sensor

    International Nuclear Information System (INIS)

    Byrd, R.C.; Longmire, J.L.; Moss, C.E.

    1995-01-01

    The task of detecting and characterizing intense bursts of nuclear radiation requires an instrument capable of operating reliably over wide extremes of signal intensity. Developing techniques for testing and calibrating such a detector involves a combination of experimental measurements, data analyses, and computer simulations. The results of these efforts provide important insight into the instrument's behavior in the laboratory and in its eventual application. For the present case, such studies not only verify the proper operation of the existing detector, but they also provide the basis for future improvements in its performance

  3. Dynamic range of low-voltage cascode current mirrors

    DEFF Research Database (Denmark)

    Bruun, Erik; Shah, Peter Jivan

    1995-01-01

    Low-voltage cascode current mirrors are reviewed with respect to the design limitations imposed if all transistors in the mirror are required to operate in the saturation region. It is found that both a lower limit and an upper limit exist for the cascode transistor bias voltage. Further, the use...... of a signal dependent cascode bias voltage is discussed and a self-biased cascode configuration is presented. This configuration makes it possible to use a higher effective gate-source voltage for the mirror transistors, hence reducing the effect of threshold voltage mismatch on the current mirror gain....... The proposed configuration has the advantage of simplicity combined with a complete elimination of the need for fixed bias voltages or bias currents in the current mirror. A disadvantage is that it requires a higher input voltage to the current mirror...

  4. I/O-Efficient Dynamic Planar Range Skyline Queries

    DEFF Research Database (Denmark)

    Kejlberg-Rasmussen, Casper; Tsakalidis, Konstantinos; Tsichlas, Kostas

    {n}{B^{1-\\epsilon}})$ blocks of space, for $n$ input planar points, $t$ reported points, and parameter $0 \\leq \\epsilon \\leq 1$. We obtain the result by extending Sundar's priority queues with attrition to support the operations \\textsc{DeleteMin} and \\textsc{CatenateAndAttrite} in $\\bigO (1)$ worst case I...

  5. Measuring quality of omnidirectional high dynamic range content

    Science.gov (United States)

    Perrin, Anne-Flore; Bist, Cambodge; Cozot, Rémi; Ebrahimi, Touradj

    2017-09-01

    Although HDR content processing, coding and quality assessment have been largely addressed in the last few years, little to no work has been concentrating on how to assess quality in HDR for 360° or omnidirectional content. This paper is an attempt to answer to various questions in this direction. As a minimum, a new data set for 360° HDR content is proposed and a new methodology is designed to assess subjective quality of HDR 360° content when it is displayed on SDR HMD after applying various tone mapping operators. The results are then analyzed and conclusions are drawn.

  6. Sensitivity and Dynamic Range Considerations for Homodyne Detection Systems

    DEFF Research Database (Denmark)

    Jaggard, Dwight L.; King, Ray J

    1973-01-01

    that the level of RF reference signal needed to obtain the maximum sensitivity was equal to or somewhat above the point where the diode changes from square law to linear detection. The results are significant in that previously reported homodyne sensitivities (not necessarily maximum) were on the order of -90...

  7. Increasing the Dynamic Range of Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Jensen, Jørgen Arendt

    2014-01-01

    are synthesized in a simulated flow phantom with linearly increasing velocity and in a dual-vessel phantom with laminar flow with peak velocities of 0.05 m/s and 0.5 m/s. The experimental measurements are made with laminar flow as in the simulations. For the simulated and experimental vessel with peak velocity...... of 0.05 m/s and flow angle of 75◦, the relative bias is -0.29% and -3.19%, and the relative standard deviations are 2.39% and 5.75% respectively. For the simulated and experimental vessel with peak velocity of 0.5 m/s and flow angle of -90◦, the relative biases are -4.30% and -7.37%, and the relative...... images. The emissions for the two imaging modes are interleaved 1-to-1 ratio, providing a high frame rate equal to the effective pulse repetition frequency of each imaging mode. The direction of the flow is estimated, and the velocity is then determined in that direction. This method Works for all angles...

  8. An objective method for High Dynamic Range source content selection

    DEFF Research Database (Denmark)

    Narwaria, Manish; Mantel, Claire; Da Silva, Matthieu Perreira

    2014-01-01

    component of such validation studies is the selection of a challenging and balanced set of source (reference) HDR content. In order to facilitate this, we present an objective method based on the premise that a more challenging HDR scene encapsulates higher contrast, and as a result will show up more...

  9. In-Situ Extended Lateral Range Surface Metrology, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop an extended lateral range capability for a dynamic optical profiling system to enable non-contact, surface roughness measurement of large and...

  10. National implementation of the UNECE convention on long-range transboundary air pollution (effects). Pt. 2. Impacts and risk estimation, critical loads, biodiversity, dynamic modelling, critical level violation, material corrosion; Nationale Umsetzung UNECE-Luftreinhaltekonvention (Wirkungen). T. 2. Wirkungen und Risikoabschaetzungen Critical Loads, Biodiversitaet, Dynamische Modellierung, Critical Levels Ueberschreitungen, Materialkorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Gauger, Thomas [Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (DE). Inst. fuer Agraroekologie (FAL-AOE); Stuttgart Univ. (Germany). Inst. fuer Navigation; Haenel, Hans-Dieter; Roesemann, Claus [Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (DE). Inst. fuer Agraroekologie (FAL-AOE); Nagel, Hans-Dieter; Becker, Rolf; Kraft, Philipp; Schlutow, Angela; Schuetze, Gudrun; Weigelt-Kirchner, Regine [OeKO-DATA Gesellschaft fuer Oekosystemanalyse und Umweltdatenmanagement mbH, Strausberg (Germany); Anshelm, Frank [Geotechnik Suedwest Frey Marx GbR, Bietigheim-Bissingen (Germany)

    2008-09-15

    The report on the implementation of the UNECE convention on long-range transboundary air pollution Pt.2 covers the following issues: The tasks of the NFC (National Focal Center) Germany including the ICP (international cooperative program) modeling and mapping and the expert panel for heavy metals. Results of the work for the multi-component protocol cover the initial data for the calculation of the critical loads following the mass balance method, critical loads for acid deposition, critical loads for nitrogen input, critical load violations (sulfur, nitrogen). The results of work for the heavy metal protocol cover methodology development and recommendations for ICO modeling and mapping in accordance with international development, contributions of the expert group/ task force on heavy metals (WGSR), data sets on the critical loads for lead, cadmium and mercury, and critical load violations (Pb, Cd, Hg). The results of work on the inclusion of biodiversity (BERN) cover data compilation, acquisition and integration concerning ecosystems, model validation and verification and the possible interpretation frame following the coupling with dynamic modeling. The future development and utilization of dynamic modeling covers model comparison, applicability, the preparation of a national data set and preparations concerning the interface to the BERN model.

  11. Super-ranging. A new ranging strategy in European badgers.

    Directory of Open Access Journals (Sweden)

    Aoibheann Gaughran

    Full Text Available We monitored the ranging of a wild European badger (Meles meles population over 7 years using GPS tracking collars. Badger range sizes varied seasonally and reached their maximum in June, July and August. We analysed the summer ranging behaviour, using 83 home range estimates from 48 individuals over 6974 collar-nights. We found that while most adult badgers (males and females remained within their own traditional social group boundaries, several male badgers (on average 22% regularly ranged beyond these traditional boundaries. These adult males frequently ranged throughout two (or more social group's traditional territories and had extremely large home ranges. We therefore refer to them as super-rangers. While ranging across traditional boundaries has been recorded over short periods of time for extraterritorial mating and foraging forays, or for pre-dispersal exploration, the animals in this study maintained their super-ranges from 2 to 36 months. This study represents the first time such long-term extra-territorial ranging has been described for European badgers. Holding a super-range may confer an advantage in access to breeding females, but could also affect local interaction networks. In Ireland & the UK, badgers act as a wildlife reservoir for bovine tuberculosis (TB. Super-ranging may facilitate the spread of disease by increasing both direct interactions between conspecifics, particularly across social groups, and indirect interactions with cattle in their shared environment. Understanding super-ranging behaviour may both improve our understanding of tuberculosis epidemiology and inform future control strategies.

  12. Rock glaciers, Zailiysiky Range, Kungei Ranges, Tienshan, Kazakhstan, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Zailiyskiy Alatau is the northernmost parallel latitudinal ranges of the Northern Tien Shan. The highest point of this range is the Talgar peak (4973 m a.s.l.)....

  13. Variable Dynamic Testbed Vehicle: Dynamics Analysis

    Science.gov (United States)

    Lee, A. Y.; Le, N. T.; Marriott, A. T.

    1997-01-01

    The Variable Dynamic Testbed Vehicle (VDTV) concept has been proposed as a tool to evaluate collision avoidance systems and to perform driving-related human factors research. The goal of this study is to analytically investigate to what extent a VDTV with adjustable front and rear anti-roll bar stiffnesses, programmable damping rates, and four-wheel-steering can emulate the lateral dynamics of a broad range of passenger vehicles.

  14. Does this range suit me? Range satisfaction of battery electric vehicle users.

    Science.gov (United States)

    Franke, Thomas; Günther, Madlen; Trantow, Maria; Krems, Josef F

    2017-11-01

    User satisfaction is a vital design criterion for sustainable systems. The present research aimed to understand factors relating to individually perceived range satisfaction of battery electric vehicle (BEV) users. Data from a large-scale BEV field trial (N = 72) were analyzed. Apart from an initial drop in range satisfaction, increasing practical experience was related to increased range satisfaction. Classical indicators of users' mobility profiles (daily travel distances) were only weakly related to lower range satisfaction (not significant), after controlling for practical experience and preferred coverage of mobility needs. The regularity/predictability of users' mobility patterns, the percentage of journeys not coverable because of range issues, and users' individual comfortable range accounted for variance in range satisfaction. Finally, range satisfaction was related to key indicators of general BEV acceptance (e.g., purchase intentions). These results underline the complex dynamics involved in individual range satisfaction, as well as its central role for BEV acceptance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Dynamical Systems Conference

    CERN Document Server

    Gils, S; Hoveijn, I; Takens, F; Nonlinear Dynamical Systems and Chaos

    1996-01-01

    Symmetries in dynamical systems, "KAM theory and other perturbation theories", "Infinite dimensional systems", "Time series analysis" and "Numerical continuation and bifurcation analysis" were the main topics of the December 1995 Dynamical Systems Conference held in Groningen in honour of Johann Bernoulli. They now form the core of this work which seeks to present the state of the art in various branches of the theory of dynamical systems. A number of articles have a survey character whereas others deal with recent results in current research. It contains interesting material for all members of the dynamical systems community, ranging from geometric and analytic aspects from a mathematical point of view to applications in various sciences.

  16. Characterizing short-range vs. long-range spatial correlations in dislocation distributions

    Energy Technology Data Exchange (ETDEWEB)

    Chevy, Juliette, E-mail: juliette.chevy@gmail.com [Laboratoire de Glaciologie et Geophysique de l' Environnement-CNRS, 54 rue Moliere, 38402 St. Martin d' Heres (France)] [Laboratoire Science et Ingenierie des Materiaux et Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 St. Martin d' Heres Cedex (France); Fressengeas, Claude; Lebyodkin, Mikhail; Taupin, Vincent [Laboratoire de Physique et Mecanique des Materiaux, Universite Paul Verlaine-Metz/CNRS, Ile du Saulcy, 57045 Metz Cedex (France); Bastie, Pierre [Laboratoire de Spectrometrie Physique, BP 87, 38402 St. Martin d' Heres Cedex (France)] [Institut Laue Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Duval, Paul [Laboratoire de Glaciologie et Geophysique de l' Environnement-CNRS, 54 rue Moliere, 38402 St. Martin d' Heres (France)

    2010-03-15

    Hard X-ray diffraction experiments have provided evidence of a strongly heterogeneous distribution of dislocation densities along the axis of cylindrical ice single crystals oriented for basal slip in torsion creep. The dislocation arrangements showed a complex scale-invariant character, which was analyzed by means of statistical and multifractal techniques. A trend to decreasing autocorrelation of the dislocation distribution was observed as deformation proceeds. At low strain levels, long-range spatial correlations control the distribution, but short-range correlations in relation with cross-slip progressively prevail when strain increases. This trend was reproduced by a model based on field dislocation dynamics, a theory accounting for both long-range elastic interactions and short-range interactions through transport of dislocation densities.

  17. Characterizing short-range vs. long-range spatial correlations in dislocation distributions

    International Nuclear Information System (INIS)

    Chevy, Juliette; Fressengeas, Claude; Lebyodkin, Mikhail; Taupin, Vincent; Bastie, Pierre; Duval, Paul

    2010-01-01

    Hard X-ray diffraction experiments have provided evidence of a strongly heterogeneous distribution of dislocation densities along the axis of cylindrical ice single crystals oriented for basal slip in torsion creep. The dislocation arrangements showed a complex scale-invariant character, which was analyzed by means of statistical and multifractal techniques. A trend to decreasing autocorrelation of the dislocation distribution was observed as deformation proceeds. At low strain levels, long-range spatial correlations control the distribution, but short-range correlations in relation with cross-slip progressively prevail when strain increases. This trend was reproduced by a model based on field dislocation dynamics, a theory accounting for both long-range elastic interactions and short-range interactions through transport of dislocation densities.

  18. Cascade Mountain Range in Oregon

    Science.gov (United States)

    Sherrod, David R.

    2016-01-01

    The Cascade mountain system extends from northern California to central British Columbia. In Oregon, it comprises the Cascade Range, which is 260 miles long and, at greatest breadth, 90 miles wide (fig. 1). Oregon’s Cascade Range covers roughly 17,000 square miles, or about 17 percent of the state, an area larger than each of the smallest nine of the fifty United States. The range is bounded on the east by U.S. Highways 97 and 197. On the west it reaches nearly to Interstate 5, forming the eastern margin of the Willamette Valley and, farther south, abutting the Coast Ranges

  19. Osprey Range - CWHR [ds601

    Data.gov (United States)

    California Natural Resource Agency — Vector datasets of CWHR range maps are one component of California Wildlife Habitat Relationships (CWHR), a comprehensive information system and predictive model for...

  20. Premelting Dynamics

    Science.gov (United States)

    Wettlaufer, J. S.; Grae Worster, M.

    2006-01-01

    When the free surfaces of most solids approach their bulk melting temperatures from below, the molecular structure of the material gives way to a disordered structure with some attributes of both the solid and liquid phases. When the temperature is sufficiently close to that of bulk transition, the surface melts and literally flows as a viscous fluid. This phenomenon, called interfacial premelting, lies at the heart of the microscopic theory of melting of solid matter, and captures the interest of condensed matter physicists and physical chemists alike. The process is ubiquitous and responsible for a wide range of consequences in materials with biological, geophysical, and technological significance. Because such systems are often exposed to spatial or temporal variations in thermodynamic forcing, there are a host of fluid mechanical phenomena that result from this underlying melting behavior. The fluid dynamics of unfrozen surfaces holds clues for understanding the bulk behavior of polycrystalline materials, from Earth's mantle to the stratosphere and beyond. In this review we focus on the fluid dynamical consequences of the premelting of solids.

  1. Boron and nitrogen doping of graphene via thermal exfoliation of graphite oxide in a BF3 or NH3 atmosphere: contrasting properties

    Czech Academy of Sciences Publication Activity Database

    Poh, H. L.; Šimek, P.; Sofer, Z.; Tomandl, Ivo; Pumera, M.

    2013-01-01

    Roč. 1, č. 42 (2013), s. 13146-13153 ISSN 2050-7488 R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : Boron and nitrogen doping * Prompt gamma-ray activation analysis * Graphene lattices Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  2. Thermodynamic stability of complexes of BF3, PF5 and AsF5 with chlorine fluorides, oxyfluorides, and related compounds

    International Nuclear Information System (INIS)

    Trowbridge, L.D.

    1996-07-01

    The recent discovery of solid, water sensitive, arsenic-containing deposits in auxiliary process piping in the PGDP led to a search for explanations that could account for such accumulated material. A plausible explanation for the deposits is the formation of complexes of AsF 5 with one or more gases that may have been present as a result of cascade equipment cleanup activities. A literature search was performed. The target of the search was literature that would provide information on the dissociation pressure of complexes of AsF 5 or its hydrolysis products with any gases that may be (at least intermittently) present in the cascade location where the deposits were found. While the precise information sought (namely reliable, accurate dissociation pressures of such complexes at cascade temperatures) was not found in the detail desired. other information on these or similar complexes was obtained which permits prediction of the conditions under which the complexes might form, dissociate, or migrate, and how they might behave in the presence of atmospheric moisture. Information was gathered on potential AsF 5 complexes with ClF, ClF 3 , ClF 5 , ClF 3 O, ClO 2 F, and ClO 3 F. Information was also collected on many other related complexes as it was encountered, particularly for series of complexes which could assist in predicting chemical trends. Thermodynamic analysis and property estimation methods have been used to generate provisional estimates of the dissociation pressures of the two complexes ClF 3 *AsF 5 and ClO 2 F*AsF 5 . In addition, several hydrolysis species have been identified, and stability properties of the most relevant such complex (H 3 O*AsF 6 ) have similarly been estimated. While the predicted dissociation pressures are somewhat uncertain. they do lead to a tentative picture of the formation and behavior of such complexes in a cascade cleanup environment

  3. Precise Range Determination Using Laser Ranging Data of LAGEOS

    Directory of Open Access Journals (Sweden)

    Kwang-Ryul Kim

    1993-12-01

    Full Text Available Satellite laser ranging observation of LAGEOS ¥± has been performed using the SLR System at Sheshan Laser Ranging Station, Shanghai Observatory. And we obtained 1,838 observational points The observed range data is corrected by means of system delay correction using ground target observation, atmospheric refraction delay correction, offset correction, general relativistic correction and tide correction including solid tide, polar tide and ocean tide. As a result, the determined range delay mean value is 19.12m and the mean internal accuracy by means of polynomial fitting and least square method is ¡¾7cm. Corrected observational points are 1,340 and noise ratio to total observational points is 27.1%

  4. Foraging optimally for home ranges

    Science.gov (United States)

    Mitchell, Michael S.; Powell, Roger A.

    2012-01-01

    Economic models predict behavior of animals based on the presumption that natural selection has shaped behaviors important to an animal's fitness to maximize benefits over costs. Economic analyses have shown that territories of animals are structured by trade-offs between benefits gained from resources and costs of defending them. Intuitively, home ranges should be similarly structured, but trade-offs are difficult to assess because there are no costs of defense, thus economic models of home-range behavior are rare. We present economic models that predict how home ranges can be efficient with respect to spatially distributed resources, discounted for travel costs, under 2 strategies of optimization, resource maximization and area minimization. We show how constraints such as competitors can influence structure of homes ranges through resource depression, ultimately structuring density of animals within a population and their distribution on a landscape. We present simulations based on these models to show how they can be generally predictive of home-range behavior and the mechanisms that structure the spatial distribution of animals. We also show how contiguous home ranges estimated statistically from location data can be misleading for animals that optimize home ranges on landscapes with patchily distributed resources. We conclude with a summary of how we applied our models to nonterritorial black bears (Ursus americanus) living in the mountains of North Carolina, where we found their home ranges were best predicted by an area-minimization strategy constrained by intraspecific competition within a social hierarchy. Economic models can provide strong inference about home-range behavior and the resources that structure home ranges by offering falsifiable, a priori hypotheses that can be tested with field observations.

  5. Genus Ranges of Chord Diagrams.

    Science.gov (United States)

    Burns, Jonathan; Jonoska, Nataša; Saito, Masahico

    2015-04-01

    A chord diagram consists of a circle, called the backbone, with line segments, called chords, whose endpoints are attached to distinct points on the circle. The genus of a chord diagram is the genus of the orientable surface obtained by thickening the backbone to an annulus and attaching bands to the inner boundary circle at the ends of each chord. Variations of this construction are considered here, where bands are possibly attached to the outer boundary circle of the annulus. The genus range of a chord diagram is the genus values over all such variations of surfaces thus obtained from a given chord diagram. Genus ranges of chord diagrams for a fixed number of chords are studied. Integer intervals that can be, and those that cannot be, realized as genus ranges are investigated. Computer calculations are presented, and play a key role in discovering and proving the properties of genus ranges.

  6. Dynamic Data Structures

    DEFF Research Database (Denmark)

    Tsakalidis, Konstantinos

    We study dynamic data structures for different variants of orthogonal range reporting query problems. In particular, we consider (1) the planar orthogonal 3-sided range reporting problem: given a set of points in the plane, report the points that lie within a given 3-sided rectangle with one....... Dynamic problems like the above arise in various applications of network optimization, VLSI layout design, computer graphics and distributed computing. For the first problem, we present dynamic data structures for internal and external memory that support planar orthogonal 3-sided range reporting queries......, and insertions and deletions of points efficiently over an average case sequence of update operations. The external memory data structures find applications in constraint and temporal databases. In particular, we assume that the coordinates of the points are drawn from different probabilistic distributions...

  7. Climate driven range divergence among host species affects range-wide patterns of parasitism

    Directory of Open Access Journals (Sweden)

    Richard E. Feldman

    2017-01-01

    Full Text Available Species interactions like parasitism influence the outcome of climate-driven shifts in species ranges. For some host species, parasitism can only occur in that part of its range that overlaps with a second host species. Thus, predicting future parasitism may depend on how the ranges of the two hosts change in relation to each other. In this study, we tested whether the climate driven species range shift of Odocoileus virginianus (white-tailed deer accounts for predicted changes in parasitism of two other species from the family Cervidae, Alces alces (moose and Rangifer tarandus (caribou, in North America. We used MaxEnt models to predict the recent (2000 and future (2050 ranges (probabilities of occurrence of the cervids and a parasite Parelaphostrongylus tenuis (brainworm taking into account range shifts of the parasite’s intermediate gastropod hosts. Our models predicted that range overlap between A. alces/R. tarandus and P. tenuis will decrease between 2000 and 2050, an outcome that reflects decreased overlap between A. alces/R. tarandus and O. virginianus and not the parasites, themselves. Geographically, our models predicted increasing potential occurrence of P. tenuis where A. alces/R. tarandus are likely to decline, but minimal spatial overlap where A. alces/R. tarandus are likely to increase. Thus, parasitism may exacerbate climate-mediated southern contraction of A. alces and R. tarandus ranges but will have limited influence on northward range expansion. Our results suggest that the spatial dynamics of one host species may be the driving force behind future rates of parasitism for another host species.

  8. Dynamics at the nanoscale

    International Nuclear Information System (INIS)

    Stoneham, A.M.; Gavartin, J.L.

    2007-01-01

    However fascinating structures may be at the nanoscale, time-dependent behaviour at the nanoscale has far greater importance. Some of the dynamics is random, with fluctuations controlling rate processes and making thermal ratchets possible. Some of the dynamics causes the transfer of energy, of signals, or of charge. Such transfers are especially efficiently controlled in biological systems. Other dynamical processes occur when we wish to control the nanoscale, e.g., to avoid local failures of gate dielectrics, or to manipulate structures by electronic excitation, to use spin manipulation in quantum information processing. Our prime purpose is to make clear the enormous range and variety of time-dependent nanoscale phenomena

  9. Advances in Dynamic Games

    CERN Document Server

    Breton, Michele

    2011-01-01

    This book focuses on various aspects of dynamic game theory, presenting state-of-the-art research and serving as a testament to the vitality and growth of the field of dynamic games and their applications. The selected contributions, written by experts in their respective disciplines, are outgrowths of presentations originally given at the 13th International Symposium of Dynamic Games and Applications held in WrocACaw. The book covers a variety of topics, ranging from theoretical developments in game theory and algorithmic methods to applications, examples, and analysis in fields as varied as

  10. Long-range correlations and asymmetry in the Bitcoin market

    Science.gov (United States)

    Alvarez-Ramirez, J.; Rodriguez, E.; Ibarra-Valdez, C.

    2018-02-01

    This work studies long-range correlations and informational efficiency of the Bitcoin market for the period from June 30, 2013 to June 3rd, 2017. To this end, the detrended fluctuation analysis (DFA) was implemented over sliding windows to estimate long-range correlations for price returns. It was found that the Bitcoin market exhibits periods of efficiency alternating with periods where the price dynamics are driven by anti-persistence. The pattern is replicated by prices samples at day, hour and second frequencies. The Bitcoin market also presents asymmetric correlations with respect to increasing and decreasing price trending, with the former trend linked to anti-persistence of returns dynamics.

  11. Eye safe laser range finders

    International Nuclear Information System (INIS)

    Snir, M.; Margaliot, M.; Amitzi, A.

    2004-01-01

    During the 1970's, Ruby (Q switched) laser based range finders with a wavelength of 694nm were first used. These lasers operated in a pulse mode within the visible light range and produced a risk for the eye retina. The laser beam striking the macula could damage the eye and might cause blindness. Over the years, Nd:YAG (Q switched) lasers were developed (operating at 1064nm) for range finding and designation uses. The wavelength of these lasers, operating in the near Infra-Red range (invisible), is also focused tightly on the retina. The human eye does not respond to the invisible light so there is no natural protection (eye blink reflex) as in the visible light. The operation of these lasers worldwide, especially when the laser beam is exposed, causes occasional eye accidents. Another risk is stemming from the use of observation systems with a high optical gain, in the laser operation areas, which enlarge the range of risk quite significantly. Therefore, research and development efforts were invested in order to introduce eye safe lasers. One of the solutions for this problem is presented in following document

  12. 2D CFD description of the kinematic effects of movable inlet and outlet die wall transport motion and punch shape geometry on the dynamics of viscous flow during ECAE through Segal 2θ-dies for a range of channel angles

    Directory of Open Access Journals (Sweden)

    Alexander V. Perig

    2017-11-01

    Full Text Available Minimization of the dead zone (DZA in the process of material forming is a materials science problem. Geometric and kinematic approaches to the minimization of the DZA during Equal Channel Angular Extrusion (ECAE have been proposed, developed, analyzed, and documented. The present article is focused on a 2D Computational Fluid Dynamics (CFD description of the kinematic effects of punch shape geometry and inlet (IDW and outlet (ODW die wall motion on the DZA during ECAE of Viscous Incompressible Continuum (VIC through a Segal 2θ-die for a range of channel angles 60° ≤ 2θ ≤ 135°. Due attention has been given to the independent alternating transport motions of the IDW and ODW. Punch shape geometry and the kinematic modes of IDW and ODW motions for DZA minimization have been determined with a numerical solution of the boundary value problem for the Navier-Stokes equations in curl transfer form for VIC. Experimental verification was accomplished with an introduction of initial circular gridlines-based physical simulation techniques. For the first time, experimental verification of CFD-derived results was made through an additional superposition of empirically-derived digital photos with deformed elliptical gridlines in the channel intersection deformation zones and correspondent 2D numerical plots with CFD-derived flow lines and full flow velocities. An empirical DZA localization was experimentally determined as the location of minimally-deformed near circular markers. The computational DZA localization was numerically determined as a flow-lines-free zone (the first hypothesis or as a zone with near-zero values of full flow velocities (the second hypothesis. The relative DZA was estimated as a ratio of the measured DZA with respect to the area of the deformation zone in the channel intersection region. A good agreement was obtained between DZA values obtained with the first hypothesis and experimental results.

  13. Wide Operational Range Thermal Sensor

    Science.gov (United States)

    Goebel, John H. (Inventor); McMurray, Robert E., Jr. (Inventor)

    2005-01-01

    Bolometer system and method for detecting, at BLIP levels, presence of radiation over a broad range of wavelengths in an infrared spectrum and in a temperature range from 20 K to as high as room temperature. The radiation is received by a Si crystal having a region that is doped with one or more of In, Ga, S, Se, Te, B, Al, P, As and Sb in a concentration ratio in a range such as 5 x 10(exp -11) to 5 x 10(exp -6). Change in electrical resistance delta R due to receipt of the radiation is measured through a change in voltage difference or current within the crystal, and the quantity delta R is converted to an estimate of the amount of radiation received. Optionally, incident radiation having an energy high enough to promote photoconductivity is removed before detection.

  14. Radio pill antenna range test

    Science.gov (United States)

    Cummins, W. F.; Kane, R. J.

    1992-05-01

    In order to investigate the potential of a proposed 'radio pill' beacon transmitter, a range test experiment was devised and carried out in the VHF frequency range. Calculations and previous work indicated that optimum sensitivity and, thus, distance would be obtained in this frequency range provided body radio-frequency (RF) absorption was not too great. A ferrite-core loop antenna is compatible with a pill geometry and has better radiation efficiency than an air core loop. The ferrite core may be a hollow cylinder with the electronics and batteries placed inside. However, this range test was only concerned with experimentally developing test range data on the ferrite core antenna itself. A one turn strap loop was placed around a 9.5 mm diameter by 18.3 mm long stack of ferrite cores. This was coupled to a 50 Omega transmission line by 76 mm of twisted pair line and a capacitive matching section. This assembly was excited by a signal generator at output levels of -10 to +10 dBm. Signals were received on a VHF receiver and tape recorder coupled to a 14 element, circularly polarized Yagi antenna at a height of 2.5 m. Field strength measurements taken at ranges of 440, 1100, and 1714 m. Maximum field strengths referenced to 0 dBm transmitter level were -107 to -110 dB at 440 m, -124 to -127 dBm at 1100 m, and -116 to -119 dBm at 1714 m when the antenna cylinder was horizontal. Field strengths with a vertical antenna were about 6 dB below these values. The latter transmit site was elevated and had a clear line-of-site path to the receiving site. The performance of this test antenna was better than that expected from method-of-moment field calculations. When this performance data is scaled to a narrow bandwidth receiving system, ground level receiving ranges of a few to 10 km can be expected. Clear line-of-sight ranges where either or both the transmitter and receiver are elevated could vary from several km to 100 km.

  15. GEA CRDA Range Data Analysis

    Science.gov (United States)

    1999-07-28

    E1, July-August 1998 18 3.3. Example 3: SatMex, Solidaridad 2, May-June 1998 27 3.4. Example 4: PanAmSat, Galaxy IV, May-June 1998 33 3.5...17 Millstone measurements residuals for Telstar 401 on Days 181-263. 26 3-18 Millstone measurement residuals for Solidaridad 1 on Days 141-153...with 29 SatMex range data. 3-19 Hermosillo B-- Solidaridad 1 range residuals through Days 135-144 with bias 30 removed. 3-20 Iztapalapa D

  16. An introduction to optimal satellite range scheduling

    CERN Document Server

    Vázquez Álvarez, Antonio José

    2015-01-01

    The satellite range scheduling (SRS) problem, an important operations research problem in the aerospace industry consisting of allocating tasks among satellites and Earth-bound objects, is examined in this book. SRS principles and solutions are applicable to many areas, including: Satellite communications, where tasks are communication intervals between sets of satellites and ground stations Earth observation, where tasks are observations of spots on the Earth by satellites Sensor scheduling, where tasks are observations of satellites by sensors on the Earth. This self-contained monograph begins with a structured compendium of the problem and moves on to explain the optimal approach to the solution, which includes aspects from graph theory, set theory, game theory and belief networks. This book is accessible to students, professionals and researchers in a variety of fields, including: operations research, optimization, scheduling theory, dynamic programming and game theory. Taking account of the distributed, ...

  17. Infinite-range quantum random Heisenberg magnet

    Science.gov (United States)

    Arrachea, Liliana; Rozenberg, Marcelo J.

    2002-06-01

    We study with exact diagonalization techniques the Heisenberg model for a system of SU(2) spins with S=1/2 and random infinite-range exchange interactions. We calculate the critical temperature Tg for the spin-glass to paramagnetic transition. We obtain Tg~0.13, in good agreement with previous quantum Monte Carlo and analytical estimates. We provide a detailed picture for the different kind of excitations which intervene in the dynamical response χ''(ω,T) at T=0 and analyze their evolution as T increases. We also calculate the specific heat Cv(T). We find that it displays a smooth maximum at TM~0.25, in good qualitative agreement with experiments. We argue that the fact that TM>Tg is due to a quantum disorder effect.

  18. A structured approach to voice range profile (phonetogram) analysis.

    Science.gov (United States)

    Sulter, A M; Wit, H P; Schutte, H K; Miller, D G

    1994-10-01

    A new method to analyze voice range profiles (phonetograms) is described. The structured analysis is based on quantitatively determining the features: shape, area, and "speaking range" dynamics, without distorting the shape of phonetograms. The parameter sets describing these features are calculated independently of fundamental frequency, which makes it possible to compare phonetograms. Two phonetograms representing a normal and a pathological example are used to illustrate the proposed method. The process provides a tool for establishing normative data for specified groups.

  19. Semiclassical dynamics

    International Nuclear Information System (INIS)

    Balazs, N.L.

    1979-01-01

    It is pointed out that in semiclassical dynamics one is encouraged to study the evolution of those curves in phase space which classically represent ensembles corresponding to wave functions. It is shown that the fixed points generate new time scales so that for times longer than the critical times, quantum dynamics will profoundly differ from classical dynamics. (P.L.)

  20. Dynamical Languages

    Science.gov (United States)

    Xie, Huimin

    The following sections are included: * Definition of Dynamical Languages * Distinct Excluded Blocks * Definition and Properties * L and L″ in Chomsky Hierarchy * A Natural Equivalence Relation * Symbolic Flows * Symbolic Flows and Dynamical Languages * Subshifts of Finite Type * Sofic Systems * Graphs and Dynamical Languages * Graphs and Shannon-Graphs * Transitive Languages * Topological Entropy