Science.gov

Sample records for temperature correction factor

  1. Temperature Corrected Bootstrap Algorithm

    NASA Technical Reports Server (NTRS)

    Comiso, Joey C.; Zwally, H. Jay

    1997-01-01

    A temperature corrected Bootstrap Algorithm has been developed using Nimbus-7 Scanning Multichannel Microwave Radiometer data in preparation to the upcoming AMSR instrument aboard ADEOS and EOS-PM. The procedure first calculates the effective surface emissivity using emissivities of ice and water at 6 GHz and a mixing formulation that utilizes ice concentrations derived using the current Bootstrap algorithm but using brightness temperatures from 6 GHz and 37 GHz channels. These effective emissivities are then used to calculate surface ice which in turn are used to convert the 18 GHz and 37 GHz brightness temperatures to emissivities. Ice concentrations are then derived using the same technique as with the Bootstrap algorithm but using emissivities instead of brightness temperatures. The results show significant improvement in the area where ice temperature is expected to vary considerably such as near the continental areas in the Antarctic, where the ice temperature is colder than average, and in marginal ice zones.

  2. An experimental and computational investigation of the standard temperature-pressure correction factor for ion chambers in kilovoltage x rays

    SciTech Connect

    La Russa, Daniel J.; McEwen, Malcolm; Rogers, D. W. O.

    2007-12-15

    For ion chambers with cavities open to the surrounding atmosphere, the response measured at a given temperature and pressure must be corrected using the standard temperature-pressure correction factor (P{sub TP}). A previous paper based solely on Monte Carlo simulations [D. J. La Russa and D. W. O. Rogers, Med. Phys. 33, 4590-4599 (2006)] pointed out the shortcomings of the P{sub TP} correction factor when used to correct the response of non-air-equivalent chambers for low-energy x-ray beams. This work presents the results of several experiments that corroborate these calculations for a number of ion chambers. Monte Carlo simulations of the experimental setup revealed additional insight into the various factors affecting the extent of the breakdown of P{sub TP}, including the effect of impurities and the sensitivity to chamber dimensions. For an unfiltered 60 kV beam, the P{sub TP}-corrected response of an NE 2571 ion chamber measured at 0.7 atm was 2.5% below the response measured at reference conditions. In general, Monte Carlo simulations of the experimental setup using EGSnrc were within 0.5% of measured values. EGSnrc-calculated values of air kerma calibration coefficients (N{sub K}) at low x-ray energies are also provided as a means of estimating the level of impurities in the chambers investigated. Calculated values of N{sub K} normalized to the value measured for a 250 kV beam were obtained for three chambers and were within 1% of experiment with one exception, the Exradin A12 in a 50 kV beam.

  3. Worldwide radiosonde temperature corrections

    SciTech Connect

    Luers, J.; Eskridge, R.

    1997-11-01

    Detailed heat transfer analyses have been performed on ten of the world`s most commonly used radiosondes from 1960 to present. These radiosondes are the USA VIZ and Space Data, the Vaisala RS-80, RS-185/21, and RS12/15, the Japanese RS2-80, Russian MARS, RKZ, and A22, and the Chinese GZZ. The temperature error of each radiosonde has been calculated as a function of altitude and the sonde and environmental parameters that influence its magnitude. Computer models have been developed that allow the correction of temperature data from each sonde as a function of these parameters. Recommendations are made concerning the use of data from each of the radiosondes for climate studies. For some radiosondes, nighttime data requires no corrections. Other radiosondes require that day and daytime data is not feasible because parameters of significance, such as balloon rise rate, are not retrievable. The results from this study provide essential information for anyone attempting to perform climate studies using radiosonde data. 6 refs., 1 tab.

  4. Temperature Correction in Probe Measurements

    NASA Astrophysics Data System (ADS)

    Gutsev, S. A.

    2015-09-01

    This work is devoted to experimental investigations of a decaying plasma using Langmuir probes. The gas pressure, the discharge current, and the moment of afterglow were selected to obtain probe characteristics in collisionless, intermediate, and drifting regimes of motion of charged particles. The manner in which the shape of the volt- ampere characteristics changes on passage from the collisionless motion to diffusion motion has been shown. A detailed analysis has been made of the source of errors arising when orbital-motion formulas or the logarithmic-operation method are applied to processing of the probe curves. It has been shown that neglect of collisions of charged particles in the probe layer leads to an ion-density value overstated more than three times, an electron-temperature value overstated two times, and an ion temperature overstated three to nine times. A model of interaction of charged particles in the probe layer has been proposed for correction of the procedure of determining temperature. Such an approach makes it possible to determine the space-charge layer in the probe, and also the value of the self-consistent field. The use of the developed procedures gives good agreement between experimental and theoretical results.

  5. Temperature correction in conductivity measurements

    USGS Publications Warehouse

    Smith, Stanford H.

    1962-01-01

    Electrical conductivity has been widely used in freshwater research but usual methods employed by limnologists for converting measurements to conductance at a given temperature have not given uniformly accurate results. The temperature coefficient used to adjust conductivity of natural waters to a given temperature varies depending on the kinds and concentrations of electrolytes, the temperature at the time of measurement, and the temperature to which measurements are being adjusted. The temperature coefficient was found to differ for various lake and stream waters, and showed seasonal changes. High precision can be obtained only by determining temperature coefficients for each water studied. Mean temperature coefficients are given for various temperature ranges that may be used where less precision is required.

  6. Use supercompressibility as a meter correction factor

    SciTech Connect

    Nelson, M.B.

    1982-09-01

    Describes how, in the range of conditions experienced in the natural gas industry, the actual density of the gas volume measured is greater than the theoretical density related to Boyle's Law, and explains how the supercompressibility factor can correct this deviation. Northern States Power decided to apply supercompressibility as part of billing procedures after a study showed that if only customers with meter pressures of 20 psig and greater had the factor applied, 95.5% of the gas that is not being accounted for would be recovered. Supercompressibility as a function of gas composition, gas pressure, and temperature indicates the empirical relationship that relates the factor to the ideal gas laws. For normal compositions of natural gas, supercompressibility can be related to the gravity of the gas, taking into account mole fractions of CO/sub 2/ and N/sub 2/.

  7. Factors of Addiction: New Jersey Correctional Population

    ERIC Educational Resources Information Center

    Wojtowicz, James P.; Liu, Tongyin; Hedgpeth, G. Wayne

    2007-01-01

    Most state inmates incarcerated under the jurisdiction of the New Jersey Department of Corrections are driven to crimes by drug abuse. Understanding the factors contributing to addiction is the first step in developing strategies for successful inmate reintegration. This study presents an analysis of inmate addiction and factor association using

  8. Factors of Addiction: New Jersey Correctional Population

    ERIC Educational Resources Information Center

    Wojtowicz, James P.; Liu, Tongyin; Hedgpeth, G. Wayne

    2007-01-01

    Most state inmates incarcerated under the jurisdiction of the New Jersey Department of Corrections are driven to crimes by drug abuse. Understanding the factors contributing to addiction is the first step in developing strategies for successful inmate reintegration. This study presents an analysis of inmate addiction and factor association using…

  9. A temperature correction method for expanding atmospheres

    NASA Astrophysics Data System (ADS)

    Hamann, W.-R.; Grfener, G.

    2003-11-01

    Model atmospheres form the basis for the interpretation of stellar spectra. A major problem in those model calculations is to establish the temperature stratification from the condition of radiative equilibrium. Dealing with non-LTE models for spherically expanding atmospheres of Wolf-Rayet stars, we developed a new temperature correction method. Its basic idea dates back to 1955 when it was proposed by Unsld for grey, static and plane-parallel atmospheres in LTE. The equations were later generalized to the non-grey case by Lucy. In the present paper we furthermore drop the Eddington approximation, proceed to spherical geometry and allow for expansion of the atmosphere. Finally the concept of an ``approximate lambda operator'' is employed to speed up the convergence. Tests for Wolf-Rayet type models demonstrate that the method works fine even in situations of strong non-LTE.

  10. Power Factor Correction to Mitigate Harmonic Distortion

    NASA Astrophysics Data System (ADS)

    Kochetkov, Gary

    Many direct current (DC) devices must receive their power from the alternating current (AC) grid. Rectifiers use diodes to create DC for these devices. Due to diodes' non-linear nature however, harmonics are created and these travel back into the grid. A significant presence of harmonics causes component heating and possible malfunction. A harmonic mitigation procedure is needed. With the correct usage of transistors, the current drawn by a rectifier can be manipulated to remove almost all harmonics. This process is called power factor correction (PFC), and formally acts to reduce the total harmonic distortion (THD) of the current. To investigate this, a three phase active rectifier was computer simulated and a controller was designed to provide switching signals for the transistors. Finally, the device was constructed in the laboratory to drive a DC motor, verifying its operating principle outside of the idealities of simulation.

  11. 49 CFR 325.73 - Microphone distance correction factors. 1

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Microphone distance correction factors. 1 325.73... MOTOR CARRIER NOISE EMISSION STANDARDS Correction Factors § 325.73 Microphone distance correction... account both the distance correction factors contained in § 325.73 and the ground surface...

  12. Elevation correction factor for absolute pressure measurements

    NASA Technical Reports Server (NTRS)

    Panek, Joseph W.; Sorrells, Mark R.

    1996-01-01

    With the arrival of highly accurate multi-port pressure measurement systems, conditions that previously did not affect overall system accuracy must now be scrutinized closely. Errors caused by elevation differences between pressure sensing elements and model pressure taps can be quantified and corrected. With multi-port pressure measurement systems, the sensing elements are connected to pressure taps that may be many feet away. The measurement system may be at a different elevation than the pressure taps due to laboratory space or test article constraints. This difference produces a pressure gradient that is inversely proportional to height within the interface tube. The pressure at the bottom of the tube will be higher than the pressure at the top due to the weight of the tube's column of air. Tubes with higher pressures will exhibit larger absolute errors due to the higher air density. The above effect is well documented but has generally been taken into account with large elevations only. With error analysis techniques, the loss in accuracy from elevation can be easily quantified. Correction factors can be applied to maintain the high accuracies of new pressure measurement systems.

  13. Chiral corrections to hyperon axial form factors

    SciTech Connect

    Jiang Fujiun; Tiburzi, B. C.

    2008-05-01

    We study the complete set of flavor-changing hyperon axial-current matrix elements at small momentum transfer. Using partially quenched heavy baryon chiral perturbation theory, we derive the chiral and momentum behavior of the axial and induced pseudoscalar form factors. The meson pole contributions to the latter posses a striking signal for chiral physics. We argue that the study of hyperon axial matrix elements enables a systematic lattice investigation of the efficacy of three-flavor chiral expansions in the baryon sector. This can be achieved by considering chiral corrections to SU(3) symmetry predictions, and their partially quenched generalizations. In particular, despite the presence of eight unknown low-energy constants, we are able to make next-to-leading order symmetry breaking predictions for two linear combinations of axial charges.

  14. Temperature-induced alpha factor

    NASA Astrophysics Data System (ADS)

    Ning, Cun-Zheng

    1998-07-01

    We study the temperature effects on gain, refractive index, and the linewidth enhancement (or alpha) factor in a 2D semiconductor. We consider both the standard alpha factor due to carrier density variation and that due to temperature variation. The so-called total alpha factor due to both carrier density and temperature is also studied. As a result of temperature change, the alpha factors can be positive, negative, or zero.

  15. Monitoring temperature for gas turbine blade: correction of reflection model

    NASA Astrophysics Data System (ADS)

    Gao, Shan; Wang, Lixin; Feng, Chi; Xiao, Yihan; Daniel, Ketui

    2015-06-01

    For a gas turbine blade working in a narrow space, the accuracy of blade temperature measurements is greatly impacted by environmental irradiation. A reflection model is established by using discrete irregular surfaces to calculate the angle factor between the blade surface and the hot adjacent parts. The model is based on the rotational angles and positions of the blades, and can correct for measurement error caused by background radiation when the blade is located at different rotational positions. This method reduces the impact of reflected radiation on the basis of the turbine's known geometry and the physical properties of the material. The experimental results show that when the blade temperature is 911.2±5 K and the vane temperature ranges from 1011.3 to 1065.8 K, the error decreases from 4.21 to 0.75%.

  16. Correction factors for assessing immersion suits under harsh conditions.

    PubMed

    Power, Jonathan; Tikuisis, Peter; Ré, António Simões; Barwood, Martin; Tipton, Michael

    2016-03-01

    Many immersion suit standards require testing of thermal protective properties in calm, circulating water while these suits are typically used in harsher environments where they often underperform. Yet it can be expensive and logistically challenging to test immersion suits in realistic conditions. The goal of this work was to develop a set of correction factors that would allow suits to be tested in calm water yet ensure they will offer sufficient protection in harsher conditions. Two immersion studies, one dry and the other with 500 mL of water within the suit, were conducted in wind and waves to measure the change in suit insulation. In both studies, wind and waves resulted in a significantly lower immersed insulation value compared to calm water. The minimum required thermal insulation for maintaining heat balance can be calculated for a given mean skin temperature, metabolic heat production, and water temperature. Combining the physiological limits of sustainable cold water immersion and actual suit insulation, correction factors can be deduced for harsh conditions compared to calm. The minimum in-situ suit insulation to maintain thermal balance is 1.553-0.0624·TW + 0.00018·TW(2) for a dry calm condition. Multiplicative correction factors to the above equation are 1.37, 1.25, and 1.72 for wind + waves, 500 mL suit wetness, and both combined, respectively. Calm water certification tests of suit insulation should meet or exceed the minimum in-situ requirements to maintain thermal balance, and correction factors should be applied for a more realistic determination of minimum insulation for harsh conditions. PMID:26674408

  17. Fermilab's Booster Correction Element Power Supply Silicon Temperature Rise

    SciTech Connect

    Krafczyk, G.; Jensen, C.; Pfeffer, H.; Warchol, G.; /Fermilab

    2009-05-01

    Fermilab is in the process of upgrading its Booster Correction Element System to include full field correction element magnets to correct position and chromaticity throughout the booster cycle. For good reliability of the switchmode power supplies designed to power the magnets, it is important to limit both the maximum temperature and the repetitive temperature cycling of the silicon junctions of the switching elements. We will describe how we measured these parameters and the results of our measurements.

  18. Correction of high-frequency noise-temperature inaccuracies

    NASA Technical Reports Server (NTRS)

    Stelzreid, C. T.

    1992-01-01

    Deep-space mission data rates to Earth are limited by the system operating noise-temperature (T(sub op)) performance of the DSN. This article addresses some of the techniques and definitions used for measuring and reporting the effective noise temperature of receivers (Te) and T(sub op) of the DSN's ground receiving systems. Calibration loads are used to measure T(sub op) of the DSN antennas. At 32 GHz, a calibration load cooled to 2-K physical temperature requires a correction of 0.67 K to determine the noise temperature. Using corrected noise temperature for the calibration loads results in the correct values for T(sub op) such that the total system noise power can be defined by Pn = kT(sub op) B, as required for DSN telecommunications design control tables. T(sub op) and Te should not be converted to equivalent physical temperatures.

  19. An Accurate Temperature Correction Model for Thermocouple Hygrometers 1

    PubMed Central

    Savage, Michael J.; Cass, Alfred; de Jager, James M.

    1982-01-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques. In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38°C). The model based on calibration at two temperatures is superior to that based on only one calibration. The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25°C, if the calibration slopes are corrected for temperature. PMID:16662241

  20. An accurate temperature correction model for thermocouple hygrometers.

    PubMed

    Savage, M J; Cass, A; de Jager, J M

    1982-02-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques.In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38 degrees C). The model based on calibration at two temperatures is superior to that based on only one calibration.The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25 degrees C, if the calibration slopes are corrected for temperature. PMID:16662241

  1. Calibration and temperature correction of heat dissipation matric potential sensors

    USGS Publications Warehouse

    Flint, A.L.; Campbell, G.S.; Ellett, K.M.; Calissendorff, C.

    2002-01-01

    This paper describes how heat dissipation sensors, used to measure soil water matric potential, were analyzed to develop a normalized calibration equation and a temperature correction method. Inference of soil matric potential depends on a correlation between the variable thermal conductance of the sensor's porous ceramic and matric poten-tial. Although this correlation varies among sensors, we demonstrate a normalizing procedure that produces a single calibration relationship. Using sensors from three sources and different calibration methods, the normalized calibration resulted in a mean absolute error of 23% over a matric potential range of -0.01 to -35 MPa. Because the thermal conductivity of variably saturated porous media is temperature dependent, a temperature correction is required for application of heat dissipation sensors in field soils. A temperature correction procedure is outlined that reduces temperature dependent errors by 10 times, which reduces the matric potential measurement errors by more than 30%. The temperature dependence is well described by a thermal conductivity model that allows for the correction of measurements at any temperature to measurements at the calibration temperature.

  2. Reflection error correction of gas turbine blade temperature

    NASA Astrophysics Data System (ADS)

    Kipngetich, Ketui Daniel; Feng, Chi; Gao, Shan

    2016-03-01

    Accurate measurement of gas turbine blades' temperature is one of the greatest challenges encountered in gas turbine temperature measurements. Within an enclosed gas turbine environment with surfaces of varying temperature and low emissivities, a new challenge is introduced into the use of radiation thermometers due to the problem of reflection error. A method for correcting this error has been proposed and demonstrated in this work through computer simulation and experiment. The method assumed that emissivities of all surfaces exchanging thermal radiation are known. Simulations were carried out considering targets with low and high emissivities of 0.3 and 0.8 respectively while experimental measurements were carried out on blades with emissivity of 0.76. Simulated results showed possibility of achieving error less than 1% while experimental result corrected the error to 1.1%. It was thus concluded that the method is appropriate for correcting reflection error commonly encountered in temperature measurement of gas turbine blades.

  3. Correcting for the Temperature Dependence of ACIS Charge Transfer Inefficiency

    NASA Astrophysics Data System (ADS)

    Posson-Brown, Jennifer; Grant, C.; Allen, G.; Plucinsky, P.; Edgar, R.

    2010-02-01

    The spectral resolution of the ACIS CCDs is substantially improved by a charge transfer inefficiency (CTI) correction algorithm included in acis_process_events. However, the behavior of the charge traps that cause CTI is temperature dependent: warmer-than-nominal focal plane temperatures reduce the effectiveness of the correction algorithm. As the insulation on the exterior of the SIM and the ACIS radiator shade have aged, the surfaces around the ACIS focal plane and radiator have become warmer, leading to FP temperatures which are sometimes a few degrees warmer than desired, particularly for observations done at spacecraft pitch angles greater than 140 degrees. The ACIS team successfully reduced average focal plane temperatures by shutting off the detector housing heater in April 2008 and a heater on the SIM was turned off in August 2009 providing additional margin, but many warm observations exist in the archive, and observations done at "tail-Sun" attitudes still often have warm focal plane temperatures. Here we review the temperature dependence of ACIS performance and present a temperature-dependent CTI correction algorithm, which we have implemented as contributed software designed to work with current CALDB products and CIAO tools. We show examples using this software to CTI-correct warm ACIS observations.

  4. 49 CFR 325.79 - Application of correction factors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... illustrate the application of correction factors to sound level measurement readings: (1) Example 1Highway operations. Assume that a motor vehicle generates a maximum observed sound level reading of 86 dB(A) during a... would be 85 dB(A), calculated as follows: 86 dB(A)Uncorrected reading +1 dB(A)Distance correction...

  5. 49 CFR 325.79 - Application of correction factors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... illustrate the application of correction factors to sound level measurement readings: (1) Example 1Highway operations. Assume that a motor vehicle generates a maximum observed sound level reading of 86 dB(A) during a... would be 85 dB(A), calculated as follows: 86 dB(A)Uncorrected reading +1 dB(A)Distance correction...

  6. Journal Impact Factor: Do the Numerator and Denominator Need Correction?

    PubMed Central

    Liu, Xue-Li; Gai, Shuang-Shuang; Zhou, Jing

    2016-01-01

    To correct the incongruence of document types between the numerator and denominator in the traditional impact factor (IF), we make a corresponding adjustment to its formula and present five corrective IFs: IFTotal/Total, IFTotal/AREL, IFAR/AR, IFAREL/AR, and IFAREL/AREL. Based on a survey of researchers in the fields of ophthalmology and mathematics, we obtained the real impact ranking of sample journals in the minds of peer experts. The correlations between various IFs and questionnaire score were analyzed to verify their journal evaluation effects. The results show that it is scientific and reasonable to use five corrective IFs for journal evaluation for both ophthalmology and mathematics. For ophthalmology, the journal evaluation effects of the five corrective IFs are superior than those of traditional IF: the corrective effect of IFAR/AR is the best, IFAREL/AR is better than IFTotal/Total, followed by IFTotal/AREL, and IFAREL/AREL. For mathematics, the journal evaluation effect of traditional IF is superior than those of the five corrective IFs: the corrective effect of IFTotal/Total is best, IFAREL/AR is better than IFTotal/AREL and IFAREL/AREL, and the corrective effect of IFAR/AR is the worst. In conclusion, not all disciplinary journal IF need correction. The results in the current paper show that to correct the IF of ophthalmologic journals may be valuable, but it seems to be meaningless for mathematic journals. PMID:26977697

  7. A Multipoint Correction Method for Environmental Temperature Changes in Airborne Double-Antenna Microwave Radiometers

    PubMed Central

    Sun, Jian; Zhao, Kai; Jiang, Tao

    2014-01-01

    This manuscript describes a new type Ka-band airborne double-antenna microwave radiometer (ADAMR) designed for detecting atmospheric supercooled water content (SCWC). The source of the measurement error is investigated by analyzing the model of the system gain factor and the principle of the auto-gain compensative technique utilized in the radiometer. Then, a multipoint temperature correction method based on the two-point calibration method for this radiometer is proposed. The multipoint temperature correction method can eliminate the effect of changes in environmental temperature by establishing the relationship between the measurement error and the physical temperatures of the temperature-sensitive units. In order to demonstrate the feasibility of the correction method, the long-term outdoor temperature experiment is carried out. The multipoint temperature correction equations are obtained by using the least square regression method. The comparison results show that the measuring accuracy of the radiometer can be increased more effectively by using the multipoint temperature correction method. PMID:24787639

  8. Differences between EPA-test and in-use fuel economy: Are the correction factors correct?

    SciTech Connect

    Mintz, M.M.; Vyas, A.R.D.; Conley, L.A.

    1993-02-01

    A vehicle`s in-use or on-the-road fuel economy often differs substantially from the miles-per-gallon estimates developed by the US Environmental Protection Agency (EPA) as part of its emissions certification program. As a result, the certification values are routinely adjusted by a set of correction factors so that the resulting estimates will better reflect in-use experience. Using data from the Residential Transportation Energy Consumption Survey conducted by the Energy Information Administration of the US Department of Energy, our analysis investigated how well the correction factors replicated the shortfall experience of all household vehicles on the road in 1985. Results show that the shortfall is larger than the EPA correction factors, and light trucks are experiencing significantly larger shortfalls than automobiles.

  9. Differences between EPA-test and in-use fuel economy: Are the correction factors correct

    SciTech Connect

    Mintz, M.M.; Vyas, A.R.D.; Conley, L.A.

    1993-01-01

    A vehicle's in-use or on-the-road fuel economy often differs substantially from the miles-per-gallon estimates developed by the US Environmental Protection Agency (EPA) as part of its emissions certification program. As a result, the certification values are routinely adjusted by a set of correction factors so that the resulting estimates will better reflect in-use experience. Using data from the Residential Transportation Energy Consumption Survey conducted by the Energy Information Administration of the US Department of Energy, our analysis investigated how well the correction factors replicated the shortfall experience of all household vehicles on the road in 1985. Results show that the shortfall is larger than the EPA correction factors, and light trucks are experiencing significantly larger shortfalls than automobiles.

  10. Correction of Temperatures of Air-Cooled Engine Cylinders for Variation in Engine and Cooling Conditions

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Pinkel, Benjamin; Ellerbrock, Herman H , Jr

    1939-01-01

    Factors are obtained from semiempirical equations for correcting engine-cylinder temperatures for variation in important engine and cooling conditions. The variation of engine temperatures with atmospheric temperature is treated in detail, and correction factors are obtained for various flight and test conditions, such as climb at constant indicated air speed, level flight, ground running, take-off, constant speed of cooling air, and constant mass flow of cooling air. Seven conventional air-cooled engine cylinders enclosed in jackets and cooled by a blower were tested to determine the effect of cooling-air temperature and carburetor-air temperature on cylinder temperatures. The cooling air temperature was varied from approximately 80 degrees F. to 230 degrees F. and the carburetor-air temperature from approximately 40 degrees F. to 160 degrees F. Tests were made over a large range of engine speeds, brake mean effective pressures, and pressure drops across the cylinder. The correction factors obtained experimentally are compared with those obtained from the semiempirical equations and a fair agreement is noted.

  11. An EGSnrc investigation of correction factors for ion chamber dosimetry

    NASA Astrophysics Data System (ADS)

    Buckley, Lesley A.

    Radiation dosimetry is used to quantify the dose delivered during radiation therapy by using ionization chambers with several correction factors. Knowledge of these factors is needed at well below the 1% level in order to maintain the overall uncertainty on the reference dosimetry near 1-2%. The small magnitude of the corrections renders measurements very difficult. Monte Carlo calculations are widely used for this purpose, however they require very low statistical uncertainties. A new user-code, CSnrc, for the EGSnrc Monte Carlo system is described. CSnrc uses a correlated sampling variance reduction technique to reduce the uncertainty for dose ratio calculations. Compared to an existing EGSnrc user-code from which it was developed, CSnrc shows gains in efficiency of up to a factor of 64 and achieves much lower statistical uncertainties on correction factors than previously published. CSnrc is used to compute the central electrode correction factor, Pcel, in a broader range of beams than previously used and at the depths relevant to modern protocols. For photon beams, the CSnrc values compare well with the values used in dosimetry protocols whereas for electron beams, CSnrc shows up to a 0.2% correction for a graphite electrode, a correction currently ignored by dosimetry protocols. The difference from currently used values is slightly less for an aluminum electrode. CSnrc is also used to compute the wall correction factor, P wall. For cylindrical chambers in photon beams, the CSnrc calculations are compared to the currently used Almond-Svensson formalism and differ from this formalism by as much as 0.8%. The CSnrc values are used to explain some previously published experiments showing problems with Pwall . For electron beams, where dosimetry protocols assume a Pwall of unity, CSnrc calculations show a correction as large as 0.6%. For parallel-plate chambers, there is little information available regarding Pwall in photon beams. CSnrc shows corrections of over 2% for some chambers. In electron beams, Pwall has been assumed to be unity, despite previously published evidence suggesting otherwise. CSnrc shows that for some chambers at lower energies, Pwall is nearly 1.02.

  12. Radiative corrections to the Casimir effect at nonzero temperatures

    SciTech Connect

    Wieczorek, E.; Robaschik, D.; Scharnhorst, K.

    1986-10-01

    Quantum electrodynamics at nonzero temperatures with boundary conditions is formulated on the basis of the functional integral using the results of previous studies (Sov. J. Nucl. Phys. 39, 663 (1984); Ann. Phys. (N.Y.) 165, 192 (1985)). The Matsubara imaginary-time formalism and the thermal field approach of perturbation theory are used. The loop corrections to the free-energy functional are calculated in a physically reasonable limit.

  13. Eucken correction in high-temperature gases with electronic excitation

    SciTech Connect

    Istomin, V. A.; Kustova, E. V. Mekhonoshina, M. A.

    2014-05-14

    In the present paper, thermal conductivity coefficient of high-temperature molecular and atomic gases with excited electronic states is studied using both the kinetic theory algorithm developed by authors earlier and the well known simple expression for the thermal conductivity coefficient proposed by Eucken and generalized by Hirschfelder. The influence of large collision diameters of excited states on the thermal conductivity is discussed. The limit of validity of the Eucken correction is evaluated on the basis of the kinetic theory calculations; an improved model suitable for air species under high-temperature conditions is proposed.

  14. Quantum mechanical corrections to simulated shock Hugoniot temperatures.

    PubMed

    Goldman, Nir; Reed, Evan J; Fried, Laurence E

    2009-11-28

    We present a straightforward method for the inclusion of quantum nuclear vibrational effects in molecular dynamics calculations of shock Hugoniot temperatures. Using a Gruneisen equation of state and a quasiharmonic approximation to the vibrational energies, we derive a simple, postprocessing method for calculation of the quantum corrected Hugoniot temperatures. We have used our novel technique on ab initio simulations of shock compressed water and methane. Our results indicate significantly closer agreement with all available experimental temperature data for these two systems. Our formalism can be easily applied to a number of different shock compressed molecular liquids or solids, and has the potential to decrease the large uncertainties inherent in many experimental Hugoniot temperature measurements of these systems. PMID:19947671

  15. Quantum Mechanical Corrections to Simulated Shock Hugoniot Temperatures

    SciTech Connect

    Goldman, N; Reed, E; Fried, L E

    2009-07-17

    The authors present a straightforward method for the inclusion of quantum nuclear vibrational effects in molecular dynamics calculations of shock Hugoniot temperatures. Using a grueneisen equation of state and a quasi-harmonic approximation to the vibrational energies, they derive a simple, post-processing method for calculation of the quantum corrected Hugoniot temperatures. They have used our novel technique on ab initio simulations of both shock compressed water and methane. Our results indicate significantly closer agreement with all available experimental temperature data for these two systems. Our formalism and technique can be easily applied to a number of different shock compressed molecular liquids or covalent solids, and has the potential to decrease the large uncertainties inherent in many experimental Hugoniot temperature measurements of these systems.

  16. 49 CFR 325.75 - Ground surface correction factors. 1

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... determine whether the motor vehicle conforms to the Standards for Highway Operations, 40 CFR 202.20. (b... the motor vehicle conforms to the Standard for Operation Under Stationary Test, 40 CFR 202.21. ... rules in subpart D of this part upon a test site which is “hard,” a correction factor of 2 dB(A)...

  17. 49 CFR 325.75 - Ground surface correction factors. 1

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... determine whether the motor vehicle conforms to the Standards for Highway Operations, 40 CFR 202.20. (b... the motor vehicle conforms to the Standard for Operation Under Stationary Test, 40 CFR 202.21. ... rules in subpart D of this part upon a test site which is “hard,” a correction factor of 2 dB(A)...

  18. Temperature Correction of Pressure-Sensitive Paints Simplified

    NASA Technical Reports Server (NTRS)

    Bencic, Timothy J.

    2000-01-01

    Pressure-sensitive paint (PSP) has become a useful tool to augment conventional pressure taps in measuring the surface pressure distribution of aerodynamic components in wind tunnel testing. Although PSP offers the advantage of nonintrusive global mapping of the surface pressure, one prominent drawback to the accuracy of this technique is the inherent temperature sensitivity of PSP's luminescent intensity. Typical aerodynamic surface PSP tests rely on the coated surface to be both spatially and temporally isothermal, along with conventional instrumentation, to yield the highest accuracy pressure mappings. In some tests, however, spatial and temporal thermal gradients are generated by the nature of the test, as in a blowing jet impinging on a surface. In these cases, high accuracy and reliable data cannot be obtained unless the temperature variations on the painted surface are accounted for. A new temperature-correction technique was developed at the NASA Glenn Research Center at Lewis Field to collapse a "family" of PSP calibration curves to a single curve of intensity ratio versus pressure. This correction allows a streamlined procedure to be followed whether or not temperature information is used in the data reduction of the PSP.

  19. Semiclassical zero-temperature corrections to Schwarzschild spacetime and holography

    SciTech Connect

    Fabbri, A.; Farese, S.; Navarro-Salas, J.; Sanchis-Alepuz, H.; Olmo, G.J.

    2006-05-15

    Motivated by the quest for black holes in anti-de Sitter braneworlds, and, in particular, by the holographic conjecture relating 5D classical bulk solutions with 4D quantum corrected ones, we numerically solve the semiclassical Einstein equations (backreaction equations) with matter fields in the (zero-temperature) Boulware vacuum state. In the absence of an exact analytical expression for in four dimensions we work within the s-wave approximation. Our results show that the quantum corrected solution is very similar to Schwarzschild spacetime until very close to the horizon, but then a bouncing surface for the radial function appears which prevents the formation of an event horizon. We also analyze the behavior of the geometry beyond the bounce, where a curvature singularity arises. In the dual theory, this indicates that the corresponding 5D static classical braneworld solution is not a black hole but rather a naked singularity.

  20. Deriving time discounting correction factors for TTO tariffs.

    PubMed

    Attema, Arthur E; Brouwer, Werner B F

    2014-04-01

    The Time Trade-off (TTO) method is a popular method for valuing health state utilities and is frequently used in economic evaluations. However, this method produces utilities that are distorted by several biases. One important bias entails the failure to incorporate time discounting. This paper aims to measure time discounting for health outcomes in a sample representative for the general population. In particular, we estimate TTO scores alongside time discounting in order to derive a set of correction factors that can be employed to correct raw TTO scores for the downward bias caused by time discounting. We find substantial positive correction factors, which are increasing with the severity of the health state. Furthermore, higher discounting is found when using more severe health states in the discounting elicitation task. More research is needed to further develop discount rate elicitation procedures and test their validity, especially in general public samples. Moreover, future research should investigate the correction of TTO values for other biases as well, such as loss aversion, and to develop a criterion to test the external validity of TTO scores. PMID:23564665

  1. Usage of dispersive effects for scale factor correction in the fiber optic gyro

    NASA Astrophysics Data System (ADS)

    Udd, Eric

    1992-02-01

    The present approach to the achievement of gyroscope scale factor corrections of the order of 100-10 ppm employs the dispersive properties of the fiber coil to monitor changes in light source spectral content. In order to demonstrate the use of this technique in spectrometer mode, the wavelength of a superradiant diode was tracked with changing temperature; the relationship between frequency and wavelength change is about 0.0025 A/Hz. For unit with 10-Hz resolution, this represents a wavelength-induced scale factor change correction of 3 ppm.

  2. Amplitude Correction Factors of Korean VLBI Network Observations

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Sung; Byun, Do-Young; Oh, Chung Sik; Kim, Hyo Ryoung; Kim, Jongsoo; Jung, Taehyun; Oh, Se-Jin; Roh, Duk-Gyoo; Jung, Dong-Kyu; Yeom, Jae-Hwan

    2015-10-01

    We report results of investigation of amplitude calibration for very long baseline interferometry (VLBI) observations with Korean VLBI Network (KVN). Amplitude correction factors are estimated based on comparison of KVN observations at 22~GHz correlated by Daejeon hardware correlator and DiFX software correlator in Korea Astronomy and Space Science Institute (KASI) with Very Long Baseline Array (VLBA) observations at 22~GHz by DiFX software correlator in National Radio Astronomy Observatory (NRAO). We used the observations for compact radio sources, 3C~454.3, NRAO~512, OJ 287, BL Lac, 3C 279, 1633+382, and 1510-089, which are almost unresolved for baselines in a range of 350-477~km. Visibility data of the sources obtained with similar baselines at KVN and VLBA are selected, fringe-fitted, calibrated, and compared for their amplitudes. We find that visibility amplitudes of KVN observations should be corrected by factors of 1.10 and 1.35 when correlated by DiFX and Daejeon correlators, respectively. These correction factors are attributed to the combination of two steps of 2-bit quantization in KVN observing systems and characteristics of Daejeon correlator.

  3. Correction factors for gravimetric measurement of peritumoural oedema in man.

    PubMed

    Bell, B A; Smith, M A; Tocher, J L; Miller, J D

    1987-01-01

    The water content of samples of normal and oedematous brain in lobectomy specimens from 16 patients with cerebral tumours has been measured by gravimetry and by wet and dry weighing. Uncorrected gravimetry underestimated the water content of oedematous peritumoural cortex by a mean of 1.17%, and of oedematous peritumoural white matter by a mean of 2.52%. Gravimetric correction equations calculated theoretically and from an animal model of serum infusion white matter oedema overestimate peritumoural white matter oedema in man, and empirical gravimetric error correction factors for oedematous peritumoural human white matter and cortex have therefore been derived. These enable gravimetry to be used to accurately determine peritumoural oedema in man. PMID:3268140

  4. Finite-temperature corrections in the dilated chiral quark model

    SciTech Connect

    Kim, Y.; Lee, Hyun Kyu |; Rho, M. |

    1995-03-01

    We calculate the finite-temperature corrections in the dilated chiral quark model using the effective potential formalism. Assuming that the dilaton limit is applicable at some short length scale, we interpret the results to represent the behavior of hadrons in dense and hot matter. We obtain the scaling law, f{sub {pi}}(T)/f{sub {pi}} = m{sub Q}(T)/m{sub Q} {approx_equal} m{sub {sigma}}(T)/m{sub {sigma}}while we argue, using PCAC, that pion mass does not scale within the temperature range involved in our Lagrangian. It is found that the hadron masses and the pion decay constant drop faster with temperature in the dilated chiral quark model than in the conventional linear sigma model that does not take into account the QCD scale anomaly. We attribute the difference in scaling in heat bath to the effect of baryonic medium on thermal properties of the hadrons. Our finding would imply that the AGS experiments (dense and hot matter) and the RHIC experiments (hot and dilute matter) will ``see`` different hadron properties in the hadronization exit phase.

  5. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... temperature corrections. 1065.670 Section 1065.670 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX...

  6. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... temperature corrections. 1065.670 Section 1065.670 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX...

  7. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... temperature corrections. 1065.670 Section 1065.670 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX...

  8. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... temperature corrections. 1065.670 Section 1065.670 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX...

  9. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... temperature corrections. 1065.670 Section 1065.670 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX...

  10. The correction model and error analysis of infrared radiation temperature measurement of semitransparent object

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaolong; Yang, Li

    2015-10-01

    Based on the theory of infrared radiation and of the infrared thermography, the mathematical correction model of the infrared radiation temperature measurement of semitransparent object is developed taking account by the effects of the atmosphere, surroundings, radiation of transmissivity and many other factors. The effects of the emissivity, transmissivity and measurement error are analysed on temperature measurement error of the infrared thermography. The measurement error of semitransparent object are compared with that of opaque object. The countermeasures to reduce the measurement error are also discussed.

  11. Correction for thermal lag in dynamic temperature measurements using resistance thermometers.

    PubMed

    Tomczuk, Krzysztof; Werszko, Radoslaw

    2013-07-01

    Periodical changes of temperature in the autoclave for the purpose of automatic control are measured with the aid of an encased resistance thermometer. To minimize dynamic errors of this thermometer, two different correcting algorithms have been employed: a known single time-constant one and an algorithm proposed by the authors-two time-constant one. The verification and comparison of the two algorithms was done using a physical model of the autoclave and a real thermometer. Additionally, three methods for the determination of time constants of the second order model were compared and factors influencing the algorithms accuracy, including time constants and sampling time, were analysed. The presented methods make possible to increase both the bandwidth of dynamical temperature measurements and its precision with relatively limited increase in computational complexity of the correction algorithm. PMID:23902092

  12. Finite-temperature electron correlations in the framework of a dynamic local-field correction

    SciTech Connect

    Schweng, H.K.; Boehm, H.M. )

    1993-07-15

    The quantum-mechanical version of the Singwi-Tosi-Land-Sjoelander (STLS) approximation is applied to finite temperatures. This approximation has two main advantages. First, it includes a dynamic local-field correction and second, it gives positive values for the pair-distribution function in the short-range region at zero temperature. This is even valid for rather low densities. After a description of the numerical difficulties arising with the use of a dynamic approximation, the results for the static-structure factor and the pair-distribution function are discussed thoroughly. Detailed work is performed on the static part of the local-field correction, with special emphasis put on the investigation of its structure. A peak is found at a wave vector [ital q][approx]2.8 (in units of the Fermi wave vector) for small temperatures, which tends towards higher values of [ital q] with increasing temperature. This peak causes an attractive particle-hole interaction in a certain [ital q] region and thus gives rise to the appearance of a charge-density wave. A parametric description is given for the static local-field correction in order to simplify further applications. Furthermore, the exchange-and-correlation free energy is considered. The results are compared with the STLS results and with the modified convolution approach.

  13. Temperature effects on pitfall catches of epigeal arthropods: a model and method for bias correction.

    PubMed

    Saska, Pavel; van der Werf, Wopke; Hemerik, Lia; Luff, Martin L; Hatten, Timothy D; Honek, Alois; Pocock, Michael

    2013-02-01

    Carabids and other epigeal arthropods make important contributions to biodiversity, food webs and biocontrol of invertebrate pests and weeds. Pitfall trapping is widely used for sampling carabid populations, but this technique yields biased estimates of abundance ('activity-density') because individual activity - which is affected by climatic factors - affects the rate of catch. To date, the impact of temperature on pitfall catches, while suspected to be large, has not been quantified, and no method is available to account for it. This lack of knowledge and the unavailability of a method for bias correction affect the confidence that can be placed on results of ecological field studies based on pitfall data.Here, we develop a simple model for the effect of temperature, assuming a constant proportional change in the rate of catch per C change in temperature, r, consistent with an exponential Q10 response to temperature. We fit this model to 38 time series of pitfall catches and accompanying temperature records from the literature, using first differences and other detrending methods to account for seasonality. We use meta-analysis to assess consistency of the estimated parameter r among studies.The mean rate of increase in total catch across data sets was 00863 00058 per C of maximum temperature and 00497 00107 per C of minimum temperature. Multiple regression analyses of 19 data sets showed that temperature is the key climatic variable affecting total catch. Relationships between temperature and catch were also identified at species level. Correction for temperature bias had substantial effects on seasonal trends of carabid catches.Synthesis and Applications. The effect of temperature on pitfall catches is shown here to be substantial and worthy of consideration when interpreting results of pitfall trapping. The exponential model can be used both for effect estimation and for bias correction of observed data. Correcting for temperature-related trapping bias is straightforward and enables population estimates to be more comparable. It may thus improve data interpretation in ecological, conservation and monitoring studies, and assist in better management and conservation of habitats and ecosystem services. Nevertheless, field ecologists should remain vigilant for other sources of bias. PMID:23539634

  14. Production of element correction factors for thermoluminescent dosimeters

    SciTech Connect

    Plato, P.; Miklos, J.

    1985-11-01

    Approximately 80 processors of personal dosimetry in the United States use thermoluminescent dosimeters (TLDs). Recent demands that dosimetry processors be able to measure radiation doses to within +/- 50% of the correct value have focused attention on the reproducibility of the TL elements within each TLD. The phosphors for these TLDs are manufactured by three companies. A dosimetry processor faces three options concerning the quality of the TL elements purchased; trust the supplier's quality control program, screen new TL elements and discard those that are extremely bad, or use element correction factors (ECFs). The first option results in dosimetry processors failing the +/- 50% accuracy requirement due to excessive variability among the TL elements. The second option still permits large precision errors that come close to the +/- 50% accuracy requirement. This paper advocates the third option and presents a 10-step procedure to produce ECFs. The procedure ensures that the ECFs represent only variations among the TL elements and not variations caused by stability problems with the TLD reader. Following is an example of ECF production for 3000 TLDs.

  15. [Research on spectrum correction algorithm of temperature measurement system based on FBG].

    PubMed

    Liu, Zhi-Chao; Yang, Jin-Hua; Wang, Gao

    2014-07-01

    In order to solve the problem that temperature sensor laying is complex and maintenance cost is high in the large-scale, multi-point real-time temperature monitoring process, the temperature monitoring system based on Fiber Bragg Grating was designed and developed. Using wavelength selectivity by optical fiber diffraction grating, a function of temperature and wavelength was established. Temperature of the measured position was inversed by calculating the wavelength variation through the optical fiber Bragg grating. Due to environmental, materials and other factors, the spectral distribution and temperature changes do not satisfy linear relationship. Therefore, designed the spectrum correction algorithm was designed, and function curve fitting of wavelength and temperature was completed with a degree of fitting greater than 99.7%. Experiments used FB136L-IAC-proof oven, LPT-200 diode, and 1 550 nm optical fiber to detect 20 to 280 degrees C temperature range of multi-point in real-time. The results show that when the temperature is changed by 1 degrees C, the corresponding center wavelength shifts about 0.04 nm to longer wavelengths. Compared with the test data from standard device, the error is less than +/- 0.3 degrees C. Meanwhile, the spectral correction algorithm was applied to the system to further improve the uniformity and accuracy of the temperature detection. Because the system uses fiber-optic sensor network, it has a strong anti-electromagnetic interference capability. The diffraction grating can achieve precise measurements, so it has big dynamic range and high accuracy. The innovation of the system is to ensure high-precision measurements, while still satisfy large-scale, multi-point, high anti-jamming capability of rapid laying, and has a strong practical value. PMID:25269282

  16. Predictors and grouping for bias correction of radiosonde temperature observations

    NASA Astrophysics Data System (ADS)

    Milan, M.; Haimberger, L.

    2015-10-01

    Due to various causes, artificial biases can be found in meteorological observations. The use of biased observations in the assimilation process leads to systematic errors in the resulting analysis unless special measures are taken during the data assimilation. One such method that avoids the assumption of unbiased input observations is the variational bias correction (VarBC), which is used successfully within the (European Centre for Medium-range Weather Forecasts) operational system, mainly to deal with satellite radiance data. In VarBC the bias of the given observation is estimated using a linear predictor model based on a small number of predefined predictors and the corresponding unknown bias parameters. These are estimated together with the model state by including a bias term in the cost function of the variational analysis. The radiosonde temperature biases depend mainly on pressure, on solar elevation, and on the instrumentation used. The optimal choice of the grouping of radiosonde stations (to get larger samples) and of the bias models is not obvious. While the method should be used in a 4D-VAR setting, its properties can be estimated off-line with much less computational effort. In this paper different methods for the grouping and the bias model are investigated, both using and not using metadata. At the same time the statistics are compared with the output of two independent homogeneity adjustment algorithms. The major outcome of this work is, apart from the development of predictors model suitable for VarBC, the detection of the high variability in the bias using grouping based on metadata.

  17. Temperature-correction of abdominal impedance: improved relationship between impedance and postmortem interval.

    PubMed

    Querido, D

    2000-03-13

    The relationship between extracellular abdominal impedance and postmortem interval (PMI) reflects the combined effects, on impedance, of postmortem cooling of the tissues and of autolysis per se. This study was performed in order to eliminate temperature change as a major factor contributing to the time course of postmortem change in abdominal impedance. Dissociation of thermal and autolytic influences was achieved by recording deep abdominal temperature at the time of impedance measurement, followed by correction of all measured impedances to their theoretically predicted values at an arbitrarily chosen temperature of 40 degrees C. Uncorrected abdominal impedance increased from 82+/-12 Ohmz, 1 h after death, to 108+/-21 Ohmz after 12 h. Impedance then decreased to 96+/-23, 89+/-22, 75+/-19, 66+/-21 and 59+/-19 Ohmz at postmortem intervals of 24, 36, 48, 60 and 72 h, respectively. In contrast, corrected abdominal impedance decreased progressively from 63+/-7 Ohmz, 1 h after death, to 61+/-9, 56+/-11, 51+/-10, 46+/-10, 39+/-11 and 35+/-10 Ohmz at postmortem intervals of 12, 24, 36, 48, 60 and 72 h, respectively. The improved relationship between (corrected) abdominal impedance and PMI is of potential value in estimating time since death. PMID:10759070

  18. Surface temperature correction for active infrared reflectance measurements of natural materials.

    PubMed

    Snyder, W C; Wan, Z

    1996-05-01

    Land surface temperature algorithms for the moderate resolution imaging spectroradiometer satellite instrument will require the spectral bidirectional reflectance distribution function (BRDF) of natural surfaces in the thermal infrared. We designed the spectral infrared bidirectional reflectance and emissivity instrument to provide such measurements by the use of a Fourier transform infrared spectrometer. A problem we encountered is the unavoidable surface heating caused by the source irradiance. For our system, the effects of the heating can cause a 30% error in the measured BRDF The error caused by heating is corrected by temporally curve fitting the radiance signal. This curve-fitting technique isolates the radiance caused by reflected irradiance. With this correction, other factors dominate the BRDF error. It is now ~5% and can be improved further. The method is illustrated with measurements of soil BRDF. PMID:21085353

  19. piggyBac-mediated phenotypic correction of factor VIII deficiency

    PubMed Central

    Staber, Janice M; Pollpeter, Molly J; Arensdorf, Angela; Sinn, Patrick L; Rutkowski, D Thomas; McCray, Paul B

    2014-01-01

    Hemophilia A, caused by a deficiency in factor VIII (FVIII), is the most severe inherited bleeding disorder. Hemophilia A is an attractive gene therapy candidate because even small increases in FVIII levels will positively alter the phenotype. While several vectors are under investigation, gene addition from an integrated transgene offers the possibility of long term expression. We engineered the DNA transposon-based vector, piggyBac (PB), to carry a codon-optimized B-domain deleted human FVIII cDNA. Evaluation of gene transfer efficiency in FVIII null mice demonstrated that PB containing the FVIII cDNA, delivered via hydrodynamic injection to immunocompetent hemophilia mice, conferred persistent gene expression, attaining mean FVIII activity of approximately 60% with 3/19 developing inhibitors. In addition to efficacious expression, a goal of gene transfer-based therapies is to develop vectors with low toxicity. To assess endoplasmic reticulum stress in hepatocytes stably expressing the transgene, we evaluated levels of ER stress markers via qPCR and found no evidence of cell stress. To evaluate phenotypic correction, a tail clip assay performed at the end of the study revealed reduced blood loss. These data demonstrate that PB can be used to achieve sustained FVIII expression and long-term therapeutic benefit in a mouse model. PMID:26015980

  20. [Study on temperature correctional models of quantitative analysis with near infrared spectroscopy].

    PubMed

    Zhang, Jun; Chen, Hua-cai; Chen, Xing-dan

    2005-06-01

    Effect of enviroment temperature on near infrared spectroscopic quantitative analysis was studied. The temperature correction model was calibrated with 45 wheat samples at different environment temperaturs and with the temperature as an external variable. The constant temperature model was calibated with 45 wheat samples at the same temperature. The predicted results of two models for the protein contents of wheat samples at different temperatures were compared. The results showed that the mean standard error of prediction (SEP) of the temperature correction model was 0.333, but the SEP of constant temperature (22 degrees C) model increased as the temperature difference enlarged, and the SEP is up to 0.602 when using this model at 4 degrees C. It was suggested that the temperature correctional model improves the analysis precision. PMID:16201365

  1. Apparatus and method for temperature correction and expanded count rate of inorganic scintillation detectors

    DOEpatents

    Ianakiev, Kiril D.; Hsue, Sin Tao; Browne, Michael C.; Audia, Jeffrey M.

    2006-07-25

    The present invention includes an apparatus and corresponding method for temperature correction and count rate expansion of inorganic scintillation detectors. A temperature sensor is attached to an inorganic scintillation detector. The inorganic scintillation detector, due to interaction with incident radiation, creates light pulse signals. A photoreceiver processes the light pulse signals to current signals. Temperature correction circuitry that uses a fast light component signal, a slow light component signal, and the temperature signal from the temperature sensor to corrected an inorganic scintillation detector signal output and expanded the count rate.

  2. High temperature image correction in DIC measurement due to thermal radiation

    NASA Astrophysics Data System (ADS)

    Wang, Shen; Yao, Xue Feng; Su, Yun Quan; Ma, Yin Ji

    2015-09-01

    In this article, the basic principle of high temperature image correction due to thermal radiation and its application in DIC high temperature measurement are investigated. First, the basic principle of high temperature image and the image gray level model due to thermal radiation are analyzed. Second, the high temperature image correction method in DIC measurement is proposed and the relationship between the gray level of high temperature image and the thermal radiation is established. Finally, the simulated high temperature image is corrected to validate the effectiveness of eliminating the thermal radiation effect in high temperature DIC, and a high temperature DIC experiment using a SiC specimen is performed to extract the high temperature displacement with high accuracy.

  3. A New Correction Technique for Strain-Gage Measurements Acquired in Transient-Temperature Environments

    NASA Technical Reports Server (NTRS)

    Richards, W. Lance

    1996-01-01

    Significant strain-gage errors may exist in measurements acquired in transient-temperature environments if conventional correction methods are applied. As heating or cooling rates increase, temperature gradients between the strain-gage sensor and substrate surface increase proportionally. These temperature gradients introduce strain-measurement errors that are currently neglected in both conventional strain-correction theory and practice. Therefore, the conventional correction theory has been modified to account for these errors. A new experimental method has been developed to correct strain-gage measurements acquired in environments experiencing significant temperature transients. The new correction technique has been demonstrated through a series of tests in which strain measurements were acquired for temperature-rise rates ranging from 1 to greater than 100 degrees F/sec. Strain-gage data from these tests have been corrected with both the new and conventional methods and then compared with an analysis. Results show that, for temperature-rise rates greater than 10 degrees F/sec, the strain measurements corrected with the conventional technique produced strain errors that deviated from analysis by as much as 45 percent, whereas results corrected with the new technique were in good agreement with analytical results.

  4. Experimental validation of beam quality correction factors for proton beams.

    PubMed

    Gomà, Carles; Hofstetter-Boillat, Bénédicte; Safai, Sairos; Vörös, Sándor

    2015-04-21

    This paper presents a method to experimentally validate the beam quality correction factors (kQ) tabulated in IAEA TRS-398 for proton beams and to determine the kQ of non-tabulated ionization chambers (based on the already tabulated values). The method is based exclusively on ionometry and it consists in comparing the reading of two ionization chambers under the same reference conditions in a proton beam quality Q and a reference beam quality (60)Co. This allows one to experimentally determine the ratio between the kQ of the two ionization chambers. In this work, 7 different ionization chamber models were irradiated under the IAEA TRS-398 reference conditions for (60)Co beams and proton beams. For the latter, the reference conditions for both modulated beams (spread-out Bragg peak field) and monoenergetic beams (pseudo-monoenergetic field) were studied. For monoenergetic beams, it was found that the experimental kQ values obtained for plane-parallel chambers are consistent with the values tabulated in IAEA TRS-398; whereas the kQ values obtained for cylindrical chambers are not consistent--being higher than the tabulated values. These results support the suggestion (of previous publications) that the IAEA TRS-398 reference conditions for monoenergetic proton beams should be revised so that the effective point of measurement of cylindrical ionization chambers is taken into account when positioning the reference point of the chamber at the reference depth. For modulated proton beams, the tabulated kQ values of all the ionization chambers studied in this work were found to be consistent with each other--except for the IBA FC65-G, whose experimental kQ value was found to be 0.6% lower than the tabulated one. The kQ of the PTW Advanced Markus chamber, which is not tabulated in IAEA TRS-398, was found to be 0.997 ± 0.042 (k = 2), based on the tabulated value of the PTW Markus chamber. PMID:25813370

  5. Experimental validation of beam quality correction factors for proton beams

    NASA Astrophysics Data System (ADS)

    Gom, Carles; Hofstetter-Boillat, Bndicte; Safai, Sairos; Vrs, Sndor

    2015-04-01

    This paper presents a method to experimentally validate the beam quality correction factors (kQ) tabulated in IAEA TRS-398 for proton beams and to determine the kQ of non-tabulated ionization chambers (based on the already tabulated values). The method is based exclusively on ionometry and it consists in comparing the reading of two ionization chambers under the same reference conditions in a proton beam quality Q and a reference beam quality 60Co. This allows one to experimentally determine the ratio between the kQ of the two ionization chambers. In this work, 7 different ionization chamber models were irradiated under the IAEA TRS-398 reference conditions for 60Co beams and proton beams. For the latter, the reference conditions for both modulated beams (spread-out Bragg peak field) and monoenergetic beams (pseudo-monoenergetic field) were studied. For monoenergetic beams, it was found that the experimental kQ values obtained for plane-parallel chambers are consistent with the values tabulated in IAEA TRS-398; whereas the kQ values obtained for cylindrical chambers are not consistentbeing higher than the tabulated values. These results support the suggestion (of previous publications) that the IAEA TRS-398 reference conditions for monoenergetic proton beams should be revised so that the effective point of measurement of cylindrical ionization chambers is taken into account when positioning the reference point of the chamber at the reference depth. For modulated proton beams, the tabulated kQ values of all the ionization chambers studied in this work were found to be consistent with each otherexcept for the IBA FC65-G, whose experimental kQ value was found to be 0.6% lower than the tabulated one. The kQ of the PTW Advanced Markus chamber, which is not tabulated in IAEA TRS-398, was found to be 0.997 0.042 (k = 2), based on the tabulated value of the PTW Markus chamber.

  6. Corrections.

    PubMed

    2015-07-01

    Griffi n MR, Grijalva CG. Restraining the pneumococcus. Lancet Infect Dis 2015; 15: 49192This linked Comment should have been accessible as Gold Open Access (CC BY) since March 19, 2015. This correction has been made to the online version as of May 22, 2015. PMID:26122438

  7. Protein folding kinetics exhibit an Arrhenius temperature dependence when corrected for the temperature dependence of protein stability

    PubMed Central

    Scalley, Michelle L.; Baker, David

    1997-01-01

    The anomalous temperature dependence of protein folding has received considerable attention. Here we show that the temperature dependence of the folding of protein L becomes extremely simple when the effects of temperature on protein stability are corrected for; the logarithm of the folding rate is a linear function of 1/T on constant stability contours in the temperaturedenaturant plane. This convincingly demonstrates that the anomalous temperature dependence of folding derives from the temperature dependence of the interactions that stabilize proteins, rather than from the super Arrhenius temperature dependence predicted for the configurational diffusion constant on a rough energy landscape. However, because of the limited temperature range accessible to experiment, the results do not rule out models with higher order temperature dependences. The significance of the slope of the stability-corrected Arrhenius plots is discussed. PMID:9380687

  8. Air Temperature Error Correction Based on Solar Radiation in an Economical Meteorological Wireless Sensor Network

    PubMed Central

    Sun, Xingming; Yan, Shuangshuang; Wang, Baowei; Xia, Li; Liu, Qi; Zhang, Hui

    2015-01-01

    Air temperature (AT) is an extremely vital factor in meteorology, agriculture, military, etc., being used for the prediction of weather disasters, such as drought, flood, frost, etc. Many efforts have been made to monitor the temperature of the atmosphere, like automatic weather stations (AWS). Nevertheless, due to the high cost of specialized AT sensors, they cannot be deployed within a large spatial density. A novel method named the meteorology wireless sensor network relying on a sensing node has been proposed for the purpose of reducing the cost of AT monitoring. However, the temperature sensor on the sensing node can be easily influenced by environmental factors. Previous research has confirmed that there is a close relation between AT and solar radiation (SR). Therefore, this paper presents a method to decrease the error of sensed AT, taking SR into consideration. In this work, we analyzed all of the collected data of AT and SR in May 2014 and found the numerical correspondence between AT error (ATE) and SR. This corresponding relation was used to calculate real-time ATE according to real-time SR and to correct the error of AT in other months. PMID:26213941

  9. Air Temperature Error Correction Based on Solar Radiation in an Economical Meteorological Wireless Sensor Network.

    PubMed

    Sun, Xingming; Yan, Shuangshuang; Wang, Baowei; Xia, Li; Liu, Qi; Zhang, Hui

    2015-01-01

    Air temperature (AT) is an extremely vital factor in meteorology, agriculture, military, etc., being used for the prediction of weather disasters, such as drought, flood, frost, etc. Many efforts have been made to monitor the temperature of the atmosphere, like automatic weather stations (AWS). Nevertheless, due to the high cost of specialized AT sensors, they cannot be deployed within a large spatial density. A novel method named the meteorology wireless sensor network relying on a sensing node has been proposed for the purpose of reducing the cost of AT monitoring. However, the temperature sensor on the sensing node can be easily influenced by environmental factors. Previous research has confirmed that there is a close relation between AT and solar radiation (SR). Therefore, this paper presents a method to decrease the error of sensed AT, taking SR into consideration. In this work, we analyzed all of the collected data of AT and SR in May 2014 and found the numerical correspondence between AT error (ATE) and SR. This corresponding relation was used to calculate real-time ATE according to real-time SR and to correct the error of AT in other months. PMID:26213941

  10. Factors Affecting Student Success in Postsecondary Academic Correctional Education Programs

    ERIC Educational Resources Information Center

    Meyer, Stephen J.

    2011-01-01

    Research in correctional education has focused on examining outcomes for participants and identifying principles and guidelines that reflect best practice. Relatively few studies have focused on postsecondary education programs and fewer still have sought to relate program implementation to student outcomes to inform program design and improve

  11. Real-Gas Correction Factors for Hypersonic Flow Parameters in Helium

    NASA Technical Reports Server (NTRS)

    Erickson, Wayne D.

    1960-01-01

    The real-gas hypersonic flow parameters for helium have been calculated for stagnation temperatures from 0 F to 600 F and stagnation pressures up to 6,000 pounds per square inch absolute. The results of these calculations are presented in the form of simple correction factors which must be applied to the tabulated ideal-gas parameters. It has been shown that the deviations from the ideal-gas law which exist at high pressures may cause a corresponding significant error in the hypersonic flow parameters when calculated as an ideal gas. For example the ratio of the free-stream static to stagnation pressure as calculated from the thermodynamic properties of helium for a stagnation temperature of 80 F and pressure of 4,000 pounds per square inch absolute was found to be approximately 13 percent greater than that determined from the ideal-gas tabulation with a specific heat ratio of 5/3.

  12. Temperature Dependence of Factors Controlling Isoprene Emissions

    NASA Technical Reports Server (NTRS)

    Duncan, Bryan N.; Yoshida, Yasuko; Damon, Megan R.; Douglass, Anne R.; Witte, Jacquelyn C.

    2009-01-01

    We investigated the relationship of variability in the formaldehyde (HCHO) columns measured by the Aura Ozone Monitoring Instrument (OMI) to isoprene emissions in the southeastern United States for 2005-2007. The data show that the inferred, regional-average isoprene emissions varied by about 22% during summer and are well correlated with temperature, which is known to influence emissions. Part of the correlation with temperature is likely associated with other causal factors that are temperature-dependent. We show that the variations in HCHO are convolved with the temperature dependence of surface ozone, which influences isoprene emissions, and the dependence of the HCHO column to mixed layer height as OMI's sensitivity to HCHO increases with altitude. Furthermore, we show that while there is an association of drought with the variation in HCHO, drought in the southeastern U.S. is convolved with temperature.

  13. Spatial correction factors for YALINA Booster facility loaded with medium and low enriched fuels

    SciTech Connect

    Talamo, A.; Gohar, Y.; Bournos, V.; Fokov, Y.; Kiyavitskaya, H.; Routkovskaya, C.

    2012-07-01

    The Bell and Glasstone spatial correction factor is used in analyses of subcritical assemblies to correct the experimental reactivity as function of the detector position. Besides the detector position, several other parameters affect the correction factor: the energy weighting function of the detector, the detector size, the energy-angle distribution of source neutrons, and the reactivity of the subcritical assembly. This work focuses on the dependency of the correction factor on the detector material and it investigates the YALINA Booster subcritical assembly loaded with medium (36%) and low (10%) enriched fuels. (authors)

  14. Ionization correction factors for H II regions in blue compact dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Holovatyi, V. V.; Melekh, B. Ya.

    2002-08-01

    Energy distributions in the spectra of the ionizing nuclei of H II regions beyond ? <= 91.2 nm were calculated. A grid of photoionization models of 270 H II regions was constructed. The free parameters of the model grid are the hydrogen density nH in the nebular gas, filling factor, energy Lc-spectrum of ionizing nuclei, and metallicity. The chemical composition from the studies of Izotov et al. were used for model grid initialization. The integral linear spectra calculated for the photoionization models were used to determine the concentration ne, temperatures Te of electrons, and ionic concentrations n(A+i)/n(H+) by the nebular gas diagnostic method. The averaged relative ionic abundances n(A+i)/n(H+) thus calculated were used to determine new expressions for ionization correction factors which we recommend for the determination of abundances in the H II regions of blue compact dwarf galaxies.

  15. Obtaining the correct sea surface temperature: bias correction of regional climate model data for the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Macias, Diego; Garcia-Gorriz, Elisa; Dosio, Alessandro; Stips, Adolf; Keuler, Klaus

    2016-02-01

    Here, the COSMO Climate Limited-area Modelling (CCLM) regional climate model (RCM) is used as external forcing for a Mediterranean basin-scale ocean model based on the general estuarine transport model (GETM). CCLM is forced by different global climate models (GCMs) (MPI and EcEarth) and by the ERA-interim (ERAin) reanalysis. Sea surface temperatures (SST) simulated by the different runs of the ocean model are compared with satellite measurements. As a substantial cold bias in simulated SST is found, a simple bias-correction methodology is applied to the RCM atmospheric variables, namely (1) air temperature (which is usually underestimated for the region by RCMs runs), (2) cloud cover (typically overestimated) and (3) wind intensity (as zonal wind intensity is usually overestimated). The performed analysis identifies wind velocity as the most important variable to correct in order to satisfactorily obtain Mediterranean SST. For many of the RCM realizations significant improvement in the simulated SST are only achieved when wind intensity values were bias-corrected towards observed values. Air temperature and cloud cover had a more marginal importance in reducing the SST bias observed in RCM-forced runs of the ocean model. By comparing the ERAin-driven run and the GCMs driven runs, our analyses suggest that the main source of observed bias is related with the GCMs being used as lateral boundary condition for the RCM realizations. However, a relative simple bias-correction methodology is sufficient to reduce a large part of the induced bias in SST and to improve the vertical water stratification characteristics within the Mediterranean basin that will allow to analyze current and future biogeochemical conditions of the studied basin.

  16. Temperature effect corrections for URAGAN based on CAO, GDAS, NOAA data

    NASA Astrophysics Data System (ADS)

    Dmitrieva, A.; Ampilogov, N.; Astapov, I.; Barbashina, N.; Borog, V.; Chernov, D.; Kovylyaeva, A.; Kokoulin, R.; Kompaniets, K.; Mannocchi, G.; Mishutina, Yu; Petrukhin, A.; Saavedra, O.; Shutenko, V.; Sit'ko, O.; Trinchero, G.; Yakovleva, E.; Yashin, I.

    2015-08-01

    For the analysis of muon flux variations caused by extra-atmospheric processes it is necessary to introduce corrections for meteorological effects. For temperature effect (TE) correction it is necessary to know the temperature profile of the atmosphere. As a rule, this profile is measured by meteorological balloons two or four times a day. Alternative sources are satellite observations and data obtained from models of atmosphere used for weather forecasting. Vertical temperature profiles obtained from NOAA satellites, GDAS (Global Data Assimilation System) and CAO data (Central Aerological Observatory, Russia) for standard isobaric levels were compared. Mean value of temperature difference for most levels does not exceed 1 K. Comparison of URAGAN data corrected for TE with CAO information, satellites and GDAS shows a good agreement. Counting rate and anisotropy of the muon flux corrected for meteorological effects for 2007-2014 are presented.

  17. Parameterized nonuniformity corrections (NUC) for non-temperature stabilized InGaAs SWIR sensing

    NASA Astrophysics Data System (ADS)

    Battaglia, Jesse; Burzi, Vincent; Moyer, Bruce; Sudol, Thomas; Passe, Joseph

    2010-04-01

    Military applications for conventional InGaAs SWIR sensing have been limited by the requirement of thermoelectric cooler (TEC) temperature stabilization for nonuniformity correction (NUC). TEC operation restricts the operating temperature range and size, weight, and power (SWAP) of these systems. For battery-powered man portable and micro UAV applications elimination of the TEC is critical. This paper discusses the advantages of our non-TEC temperature parameterized NUC corrections algorithms versus TEC stabilized architectures. The corrections algorithms enable performance-tuned polynomial order correction of both pixel uniformity and temperature parameterization for each SWIR sensor. These advances enable SWIR InGaAs sensing to meet the SWAP requirements of next generation military applications.

  18. Beta and Gamma Correction Factors for the Eberline R0-20 Ionization Chamber Survey Instrument

    SciTech Connect

    Johnson, Michelle L.; Rathbone, Bruce A.; Bratvold, Thomas E.

    2001-08-10

    This technical document provides details of derived correction factors for the Eberline R0-20 survey meter, which uses an ionization chamber to measure ambient exposure rates. A thin end window allows the instrument to measure exposure rates from non-penetrating radiation (i.e., beta radiation). Correction factors are provided for contact measurements with beta and gamma disk sources, gamma beams and, finally, general area beta fields. Beta correction factors are based on the instrument's response to 204Tl, selected as the most conservative isotope for beta correction factors, as indicated in previous studies of similar instruments using 204Tl, 147Pm, and 90Sr(Y) isotopes (LANL 1982). Gamma correction factors are based on 137Cs, considered the predominant source of gamma radiation on the Hanford Site.

  19. Correction

    NASA Astrophysics Data System (ADS)

    1998-12-01

    Alleged mosasaur bite marks on Late Cretaceous ammonites are limpet (patellogastropod) home scars Geology, v. 26, p. 947 950 (October 1998) This article had the following printing errors: p. 947, Abstract, line 11, “sepia” should be “septa” p. 947, 1st paragraph under Introduction, line 2, “creep” should be “deep” p. 948, column 1, 2nd paragraph, line 7, “creep” should be “deep” p. 949, column 1, 1st paragraph, line 1, “creep” should be “deep” p. 949, column 1, 1st paragraph, line 5, “19774” should be “1977)” p. 949, column 1, 4th paragraph, line 7, “in particular” should be “In particular” CORRECTION Mammalian community response to the latest Paleocene thermal maximum: An isotaphonomic study in the northern Bighorn Basin, Wyoming Geology, v. 26, p. 1011 1014 (November 1998) An error appeared in the References Cited. The correct reference appears below: Fricke, H. C., Clyde, W. C., O'Neil, J. R., and Gingerich, P. D., 1998, Evidence for rapid climate change in North America during the latest Paleocene thermal maximum: Oxygen isotope compositions of biogenic phosphate from the Bighorn Basin (Wyoming): Earth and Planetary Science Letters, v. 160, p. 193 208.

  20. Correction.

    PubMed

    2015-05-22

    The Circulation Research article by Keith and Bolli (String Theory of c-kitpos Cardiac Cells: A New Paradigm Regarding the Nature of These Cells That May Reconcile Apparently Discrepant Results. Circ Res. 2015:116:1216-1230. doi: 10.1161/CIRCRESAHA.116.305557) states that van Berlo et al (2014) observed that large numbers of fibroblasts and adventitial cells, some smooth muscle and endothelial cells, and rare cardiomyocytes originated from c-kit positive progenitors. However, van Berlo et al reported that only occasional fibroblasts and adventitial cells derived from c-kit positive progenitors in their studies. Accordingly, the review has been corrected to indicate that van Berlo et al (2014) observed that large numbers of endothelial cells, with some smooth muscle cells and fibroblasts, and more rarely cardiomyocytes, originated from c-kit positive progenitors in their murine model. The authors apologize for this error, and the error has been noted and corrected in the online version of the article, which is available at http://circres.ahajournals.org/content/116/7/1216.full ( PMID:25999426

  1. Correction.

    PubMed

    2015-04-01

    In the article by Eicken et al (Eicken A, Schubert S, Hager A, Hrer J, McElhinney DB, Hess J, Ewert P, Berger F. Percutaneous trcuspid valve implantation: two-center experience with midterm results. Circ Cardiovasc Interv. 2015;8:e002155. DOI: 10.1161/CIRCINTERVENTIONS.114.002155.), which published online April 14, 2015, and appears in the April 2015 issue of the journal, a correction was needed. On page 1, in the affiliations footnote, Klinik fr Herz-und Gefschirurgie (S.S., F.B.), Deutsches Herzzentrum Mnchen, Technische Universitt Mnchen, Munich, Germany; Klinik fr Kinderkardiologie und angeborene Herzfehler, Deutsches Herzzentrum Berlin, Berlin, Germany (J. Hrer), has been changed to read, Klinik fr Herz-und Gefschirurgie (J. Hrer), Deutsches Herzzentrum Mnchen, Munich, Germany; Klinik fr Kinderkardiologie und angeborene Herzfehler, Deutsches Herzzentrum Berlin, Berlin, Germany (S.S., F.B.). The authors regret the error. This correction has been made to the online version of the article, which is available at http:// circinterventions.ahajournals.org/content/8/4/e002155. PMID:25954778

  2. Temperature gain correction for CsI(Tl) detection systems based on digital pulse shape analysis

    NASA Astrophysics Data System (ADS)

    Silva, J.; Fiori, E.; Isaak, J.; Lher, B.; Savran, D.; Vencelj, M.; Wamers, F.

    2015-03-01

    In this paper we propose a pulse shape based method for monitoring the interior temperature of a CsI(Tl) crystal in order to correct the temperature dependence in the energy calibration of the corresponding detector system. The gain dependence on temperature of the CsI(Tl) detector was measured using both, a photomultiplier tube (PMT) and an avalanche photodiode (APD) readout photosensor. The analysis shows that the gain shifts due to temperature variations can be corrected to a precision of better than 1% with both the PMT and the APD, well below the CsI(Tl) intrinsic energy resolution for ~1 MeV ?-rays.

  3. Correction.

    PubMed

    2015-10-01

    In the article by Quintavalle et al (Quintavalle C, Anselmi CV, De Micco F, Roscigno G, Visconti G, Golia B, Focaccio A, Ricciardelli B, Perna E, Papa L, Donnarumma E, Condorelli G, Briguori C. Neutrophil gelatinaseassociated lipocalin and contrast-induced acute kidney injury. Circ Cardiovasc Interv. 2015;8:e002673. DOI: 10.1161/CIRCINTERVENTIONS.115.002673.), which published online September 2, 2015, and appears in the September 2015 issue of the journal, a correction was needed. On page 1, the institutional affiliation for Elvira Donnarumma, PhD, SDN Foundation, has been changed to read, IRCCS SDN, Naples, Italy. The institutional affiliation for Laura Papa, PhD, Institute for Endocrinology and Experimental Oncology, National Research Council, Naples, Italy, has been changed to read, Institute of Genetics and Biomedical Research, Milan Unit, Milan, Italy and Humanitas Research Hospital, Rozzano, Italy. The authors regret this error. PMID:26420816

  4. Experimental verification of Theodorsen's theoretical jet-boundary correction factors

    NASA Technical Reports Server (NTRS)

    Schliestett, George Van

    1934-01-01

    Prandtl's suggested use of a doubly infinite arrangement of airfoil images in the theoretical determination of wind-tunnel jet-boundary corrections was first adapted by Glauert to the case of closed rectangular jets. More recently, Theodorsen, using the same image arrangement but a different analytical treatment, has extended this work to include not only closed but also partly closed and open tunnels. This report presents the results of wind-tunnel tests conducted at the Georgia School of Technology for the purpose of verifying the five cases analyzed by Theodorsen. The tests were conducted in a square tunnel and the results constitute a satisfactory verification of his general method of analysis. During the preparation of the data two minor errors were discovered in the theory and these have been rectified.

  5. A method to correct for temperature dependence and measure simultaneously dose and temperature using a plastic scintillation detector.

    PubMed

    Therriault-Proulx, Francois; Wootton, Landon; Beddar, Sam

    2015-10-21

    Plastic scintillation detectors (PSDs) work well for radiation dosimetry. However, they show some temperature dependence, and a priori knowledge of the temperature surrounding the PSD is required to correct for this dependence. We present a novel approach to correct PSD response values for temperature changes instantaneously and without the need for prior knowledge of the temperature value. In addition to rendering the detector temperature-independent, this approach allows for actual temperature measurement using solely the PSD apparatus. With a temperature-controlled water tank, the temperature was varied from room temperature to more than 40 C and the PSD was used to measure the dose delivered from a cobalt-60 photon beam unit to within an average of 0.72% from the expected value. The temperature was measured during each acquisition with the PSD and a thermocouple and values were within 1 C of each other. The depth-dose curve of a 6 MV photon beam was also measured under warm non-stable conditions and this curve agreed to within an average of??-0.98% from the curve obtained at room temperature. The feasibility of rendering PSDs temperature-independent was demonstrated with our approach, which also enabled simultaneous measurement of both dose and temperature. This novel approach improves both the robustness and versatility of PSDs. PMID:26407188

  6. A method to correct for temperature dependence and measure simultaneously dose and temperature using a plastic scintillation detector

    NASA Astrophysics Data System (ADS)

    Therriault-Proulx, Francois; Wootton, Landon; Beddar, Sam

    2015-10-01

    Plastic scintillation detectors (PSDs) work well for radiation dosimetry. However, they show some temperature dependence, and a priori knowledge of the temperature surrounding the PSD is required to correct for this dependence. We present a novel approach to correct PSD response values for temperature changes instantaneously and without the need for prior knowledge of the temperature value. In addition to rendering the detector temperature-independent, this approach allows for actual temperature measurement using solely the PSD apparatus. With a temperature-controlled water tank, the temperature was varied from room temperature to more than 40 C and the PSD was used to measure the dose delivered from a cobalt-60 photon beam unit to within an average of 0.72% from the expected value. The temperature was measured during each acquisition with the PSD and a thermocouple and values were within 1 C of each other. The depth-dose curve of a 6 MV photon beam was also measured under warm non-stable conditions and this curve agreed to within an average of??-0.98% from the curve obtained at room temperature. The feasibility of rendering PSDs temperature-independent was demonstrated with our approach, which also enabled simultaneous measurement of both dose and temperature. This novel approach improves both the robustness and versatility of PSDs.

  7. Individualized correction factors in the preselection of hearing aids.

    PubMed

    Fikret-Pasa, S; Revit, L J

    1992-04-01

    This study investigated three issues involving corrections for individual ear acoustics in hearing aid prescriptions: (a) the extent to which inconsistencies in the sound-field reference position can affect comparative corrections for the real-ear unaided response (REUR); (b) the extent to which individual variability in the real-ear-to-coupler level difference (RECD) supports the use of individual measurements as opposed to an average-ear estimate; and (c) the adequacy of using KEMAR estimates of the effects of the location of the hearing aid microphone. In Experiment 1, KEMAR REURs using over-the-ear and under-the-ear reference positions were compared with KEMAR REURs using a center-of-head reference position. Maximum differences of 4-9 dB were found in the 1500- to 5000-Hz range, depending on test conditions. In Experiment 2, the ear canal response of an insert earphone was compared to the 2-cc coupler response of the same earphone to calculate the RECD. Individual RECDs for a population of hearing aid candidates were compared to the RECD for KEMAR. For 8 of the 15 subjects (9 of 18 ears), the RECD was more than 4 dB different from KEMAR at two or more third-octave frequencies between 500 and 4000 Hz. In Experiment 3, the effect of the location of the hearing aid microphone for in-the-ear (ITE) and in-the-canal (ITC) locations was compared with the over-the-ear (OTE) location for 18 ears and for KEMAR. The effects varied across individual ears, but all ears and KEMAR showed positive gain in the high frequencies for the ITE and ITC locations. The relevance of these results to hearing aid prescription practices is discussed. PMID:1573878

  8. LIGHT-DUTY DIESEL EMISSION CORRECTION FACTORS FOR AMBIENT CONDITIONS

    EPA Science Inventory

    Since emission measurements from passenger cars are performed at one standard set of ambient conditions and since emission rates of HC, CO, and NOx are sensitive to temperature and humidity, it is necessary to determine the influence of ambient conditions on emissions from major ...

  9. 49 CFR 325.73 - Microphone distance correction factors. 1

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... factors. 1 1 Table 1, in 325.7 is a tabulation of the maximum allowable sound level readings taking into... target point is other than 50 feet (15.2 m), the maximum observed sound level reading generated by the... observed sound level readings generated by the motor vehicle in accordance with 325.59 of this part...

  10. An ultrasonic air temperature measurement system with self-correction function for humidity

    NASA Astrophysics Data System (ADS)

    Tsai, Wen-Yuan; Chen, Hsin-Chieh; Liao, Teh-Lu

    2005-02-01

    This paper proposes an ultrasonic measurement system for air temperature with high accuracy and instant response. It can measure the average temperature of the environmental air by detecting the changes of the speed of the ultrasound in the air. The changes of speed of sound are computed from combining variations of time-of-flight (TOF) from a binary frequency shift-keyed (BFSK) ultrasonic signal and phase shift from continuous waves [11]. In addition, another proposed technique for the ultrasonic air temperature measurement is the self-correction functionality within a highly humid environment. It utilizes a relative humidity/water vapour sensor and applies the theory of how sound speed changes in a humid environment. The proposed new ultrasonic air temperature measurement has the capability of self-correction for the environment variable of humidity. Especially under the operational environment with high fluctuations of various humidity levels, the proposed system can accurately self-correct the errors on the conventional ultrasonic thermometer caused by the changing density of the vapours in the air. Including the high humidity effect, a proof-of-concept experiment demonstrates that in dry air (relative humidity, RH = 10%) without humidity correction, it is accurate to 0.4 C from 0 C to 80 C, while in highly humid air (relative humidity, RH = 90%) with self-correction functionality, it is accurate to 0.3 C from 0 C to 80 C with 0.05% resolution and temperature changes are instantly reflected within 100 ms.

  11. Quantum gravitational correction to the Hawking temperature from the Lemaitre-Tolman-Bondi model

    SciTech Connect

    Banerjee, Rabin; Majhi, Bibhas Ranjan; Kiefer, Claus

    2010-08-15

    We solve the quantum constraint equations of the Lemaitre-Tolman-Bondi model in a semiclassical approximation in which an expansion is performed with respect to the Planck length. We recover in this way the standard expression for the Hawking temperature as well as its first quantum gravitational correction. We then interpret this correction in terms of the one-loop trace anomaly of the energy-momentum tensor and thereby make contact with earlier work on quantum black holes.

  12. Correction of factor XI deficiency by liver transplantation.

    PubMed

    Gupta, Eva; Finn, Laura; Johns, Gretchen; Pruthi, Rajiv K; Roy, Vivek

    2015-12-01

    Orthotopic liver transplantation for other diseases typically results in a coincidental cure for hemophilia A and B; however, long-term outcomes of liver transplant in hemophilia C are not very well described. Herein, the authors report a patient of severe congenital factor XI (FXI) deficiency who received an orthotopic liver transplant. The authors discuss the perioperative management and long-term outcomes. The normalization of his FXI levels confirms that the liver is the most clinically relevant site of synthesis of FXI. PMID:26196192

  13. Global analysis of proton elastic form factor data with two-photon exchange corrections

    SciTech Connect

    J. Arrington; W. Melnitchouk; J. A. Tjon

    2007-09-01

    We use the world's data on elastic electron-proton scattering and calculations of two-photon exchange effects to extract corrected values of the proton's electric and magnetic form factors over the full Q^2 range of the existing data. Our analysis combines the corrected Rosenbluth cross section and polarization transfer data, and is the first extraction of G_Ep and G_Mp including explicit two-photon exchange corrections and their associated uncertainties. In addition, we examine the angular dependence of the corrected cross sections, and discuss the possible nonlinearities of the cross section as a function of epsilon.

  14. New look at displacement factor and point of measurement corrections in ionization chamber dosimetry

    SciTech Connect

    Awschalom, M.; Rosenberg, I.; Ten Haken, R.K.

    1983-05-01

    A new technique is presented for determination of the effective point of measurement when cavity ionization chambers are used to measure the absorbed dose due to ionizing radiation in a dense medium. An algorithm is derived relating the effective point of measurement to the displacement correction factor. This algorithm relates variations of the displacement factor to the radiation field gradient. The technique is applied to derive the magnitudes of the corrections for several chambers in a p(66)Be(49) neutron therapy beam.

  15. Self-attenuation correction factors for bioindicators measured by ? spectrometry for energies <100 keV

    NASA Astrophysics Data System (ADS)

    Manduci, L.; Tenailleau, L.; Trolet, J. L.; De Vismes, A.; Lopez, G.; Piccione, M.

    2010-01-01

    The mass attenuation coefficients for a number of marine and terrestrial bioindicators were measured using ? spectrometry for energies between 22 and 80 keV. These values were then used to find the correction factor k for the apparent radioactivity. The experimental results were compared with a Monte Carlo simulation performed using PENELOPE in order to evaluate the reliability of the simplified calculation and to determine the correction factors.

  16. Temperature correction of arterial blood-gas parameters: A comparative review of methodology.

    PubMed

    Andritsch, R F; Muravchick, S; Gold, M I

    1981-09-01

    The need for accurate clinical diagnosis and appropriate intervention requires that a modern blood-gas laboratory have the means to correct for significant discrepancies between patient temperature and the temperature at which in vitro blood samples are analyzed. Recent advances in mini- and microcomputer technology permit application of any or all of the correction formulas above at modest cost and minimal inconvenience (See the Appendix). An expanded program for a TI-59 desk-top calculator and P-100C printer which gives labeled hard-copy readout of temperature-corrected pH, PCO2, PO2, and hemoglobin saturation values, as well as bicarbonate concentration and in vivo base excess is in daily clinical use in our operating room and is available from the authors upon request. PMID:6791530

  17. Calibration auto-correction method in Raman distributed temperature sensing system using fiber coil configuration

    NASA Astrophysics Data System (ADS)

    Pan, Liang; Liu, Tiegen; Jiang, Junfeng; Liu, Kun; Chen, Qinnan; Ma, Chunyu

    2015-08-01

    A novel method to auto-correct the fluctuation of calibration in Raman distributed temperature sensor is proposed in this paper. The proposed scheme combines a fiber coil configuration with a Pt-resistance in the front section to cancel out the impact of fluctuation generated by perturbations of the laser and APD, instability of power supply and environment temperature changes. The sensor performance is significantly improved by exploiting the fiber coil and Pt-resistance to correct the temperature calibration. Our theoretical analysis shows that with the calibration of temperature autocorrection method the sensing system is more suitable for various environments and provides low uncertainty in long term operation, and it has the potential to accurate temperature calibration with simple equipment and to reduce costs of the system.

  18. Note: A new truncation correction for the configurational temperature extends its applicability to interaction potentials with a discontinuous force.

    PubMed

    Lervik, Anders; Wilhelmsen, ivind; Trinh, Thuat T; Blokhuis, Edgar M

    2016-02-01

    We present a simple truncation correction for the configurational temperature which, unlike previous corrections, works even at low truncation values for the shifted and truncated Lennard-Jones potential. The success of the new correction suggests that the expression for the configurational temperature is valid also for interaction potentials with a discontinuous force, given that the discontinuity is properly accounted for. PMID:26851934

  19. Temperature corrections to the thermodynamic functions of a degenerate neutron gas in a magnetic field

    SciTech Connect

    Skobelev, V. V.

    2011-08-15

    Temperature corrections to the basic thermodynamic functions calculated in our earlier publication for a degenerate neutron gas in a magnetic field are determined taking into account the anomalous magnetic moment of a neutron. The heat capacity and entropy of the degenerate neutron gas, as well as the temperature correction to the magnetic susceptibility, are also calculated. Additional arguments supporting the effect of an increase in the pulse frequency of pulsars mentioned in the previous publication are formulated; the results of that publication are refined.

  20. The perturbation correction factor of ionisation chambers in beta-radiation fields.

    PubMed

    Böhm, J

    1980-01-01

    In determining the absorbed dose in a solid medium by means of gas-filled ionisation chambers, the perturbation of the radiation field by the chamber needs to be taken into account. So far, an appropriate correction factor has neither been calculated nor measured for beta-radiation. This work describes its experimental determination for an extrapolation chamber and beta-radiation fields of 147Pm, 204Tl, and 90Sr + 90Y. The results show that the correction factor may be assumed to be the product of a shield factor and a scatter factor the magnitudes of which depend on the chamber geometry and the radiation field. The change of the perturbation correction factor with phantom depth is important for the measurement of depth dose curves. This is demonstrated by an example. PMID:7360793

  1. Evaluating sedimentary basins for geothermal power production potential and bottom-hole temperature corrections

    NASA Astrophysics Data System (ADS)

    Crowell, Anna M.

    At present, the risks and costs associated with geothermal energy wildcat exploration are prohibitive. With improved technology, the future may be brighter, and a play fairway analysis, for geothermal exploration can guide development. Comparing geophysical data with geothermal gradient allows identification of potentially economic areas of interest. The play fairway analysis is a common tool used by the petroleum industry to identify areas for potential exploration. The analysis identifies areas in the Denver, Illinois, Michigan, and Williston Basins with the highest development potential. A great deal of data have potential for a play fairway analysis, but data quality is problematic due to systematic errors in bottom-hole temperatures (BHTs). Corrections to bottom-hole temperatures are necessary due to the perturbation of temperature caused by the drilling mud, and can range from 5 to 30 C. Correction schemes for bottom-hole temperatures can be applied to both the energy-in-place estimates and play fairway analyses. The Harrison equation is the most accurate for basins less than 4.5 km deep. The Kehle correction is the most accurate for basins deeper than 4.5 km. Chapter II explains why BHTs grouped by depth are more statistically robust than those grouped by geochronological unit. Chapter III demonstrates why the Harrison Equation is the best correction method to use for BHTs. Chapters IV and V give the volumetric energy-in-place for the Denver, Illinois, and Michigan Basins for discrete temperature ranges, and Chapter 6 provides the final Play Fairway Favorability maps.

  2. Reproduction of surface air temperature over South Korea using dynamical downscaling and statistical correction

    NASA Astrophysics Data System (ADS)

    Ahn, J.; Lee, J.; Shim, K.; Kim, Y.

    2013-12-01

    In spite of dense meteorological observation conducting over South Korea (The average distance between stations: ~ 12.7km), the detailed topographical effect is not reflected properly due to its mountainous terrains and observation sites mostly situated on low altitudes. A model represents such a topographical effect well, but due to systematic biases in the model, the general temperature distribution is sometimes far different from actual observation. This study attempts to produce a detailed mean temperature distribution for South Korea through a method combining dynamical downscaling and statistical correction. For the dynamical downscaling, a multi-nesting technique is applied to obtain 3-km resolution data with a focus on the domain for the period of 10 years (1999-2008). For the correction of systematic biases, a perturbation method divided into the mean and the perturbation part was used with a different correction method being applied to each part. The mean was corrected by a weighting function while the perturbation was corrected by the self-organizing maps method. The results with correction agree well with the observed pattern compared to those without correction, improving the spatial and temporal correlations as well as the RMSE. In addition, they represented detailed spatial features of temperature including topographic signals, which cannot be expressed properly by gridded observation. Through comparison with in-situ observation with gridded values after objective analysis, it was found that the detailed structure correctly reflected topographically diverse signals that could not be derived from limited observation data. We expect that the correction method developed in this study can be effectively used for the analyses and projections of climate downscaled by using region climate models. Acknowledgements This work was carried out with the support of Korea Meteorological Administration Research and Development Program under Grant CATER 2012-3083 and Rural Development Administration Cooperative Research Program for Agriculture Science and Technology Development under Grant Project No. PJ009353, Republic of Korea. Reference Ahn, J.-B., Lee, J.-L., and Im, E.-S., 2012: The reproducibility of surface air temperature over South Korea using dynamical downscaling and statistical correction, J. Meteor. Soc. Japan, 90, 493-507, doi: 10.2151/jmsj.2012-404

  3. Comparison between CARS and corrected thermocouple temperature measurements in a diffusion flame

    SciTech Connect

    Farrow, R.L.; Mattern, P.L.; Rahn, L.A.

    1982-09-01

    Coherent anti-Stokes Raman spectroscopy (CARS) has been used to obtain radial temperature profiles in an axisymmetric methane diffusion flame. Temperatures were obtained from analysis of background-free nitrogen Q- and O-branch spectra. The spectra were analyzed with a nonlinear least-squares CARS fitting program and compared to measurements from radiation- and conduction-corrected thermocouples. Excellent agreement was obtained in regions of relatively constant temperature, whereas improved CARS spatial resolution was required to obtain agreement near steep temperature gradients.

  4. Statistical Correction of Air Temperature Forecasts for City and Road Weather Applications

    NASA Astrophysics Data System (ADS)

    Mahura, Alexander; Petersen, Claus; Sass, Bent; Gilet, Nicolas

    2014-05-01

    The method for statistical correction of air /road surface temperatures forecasts was developed based on analysis of long-term time-series of meteorological observations and forecasts (from HIgh Resolution Limited Area Model & Road Conditions Model; 3 km horizontal resolution). It has been tested for May-Aug 2012 & Oct 2012 - Mar 2013, respectively. The developed method is based mostly on forecasted meteorological parameters with a minimal inclusion of observations (covering only a pre-history period). Although the st iteration correction is based taking into account relevant temperature observations, but the further adjustment of air and road temperature forecasts is based purely on forecasted meteorological parameters. The method is model independent, e.g. it can be applied for temperature correction with other types of models having different horizontal resolutions. It is relatively fast due to application of the singular value decomposition method for matrix solution to find coefficients. Moreover, there is always a possibility for additional improvement due to extra tuning of the temperature forecasts for some locations (stations), and in particular, where for example, the MAEs are generally higher compared with others (see Gilet et al., 2014). For the city weather applications, new operationalized procedure for statistical correction of the air temperature forecasts has been elaborated and implemented for the HIRLAM-SKA model runs at 00, 06, 12, and 18 UTCs covering forecast lengths up to 48 hours. The procedure includes segments for extraction of observations and forecast data, assigning these to forecast lengths, statistical correction of temperature, one-&multi-days statistical evaluation of model performance, decision-making on using corrections by stations, interpolation, visualisation and storage/backup. Pre-operational air temperature correction runs were performed for the mainland Denmark since mid-April 2013 and shown good results. Tests also showed that the CPU time required for the operational procedure is relatively short (less than 15 minutes including a large time spent for interpolation). These also showed that in order to start correction of forecasts there is no need to have a long-term pre-historical data (containing forecasts and observations) and, at least, a couple of weeks will be sufficient when a new observational station is included and added to the forecast point. Note for the road weather application, the operationalization of the statistical correction of the road surface temperature forecasts (for the RWM system daily hourly runs covering forecast length up to 5 hours ahead) for the Danish road network (for about 400 road stations) was also implemented, and it is running in a test mode since Sep 2013. The method can also be applied for correction of the dew point temperature and wind speed (as a part of observations/ forecasts at synoptical stations), where these both meteorological parameters are parts of the proposed system of equations. The evaluation of the method performance for improvement of the wind speed forecasts is planned as well, with considering possibilities for the wind direction improvements (which is more complex due to multi-modal types of such data distribution). The method worked for the entire domain of mainland Denmark (tested for 60 synoptical and 395 road stations), and hence, it can be also applied for any geographical point within this domain, as through interpolation to about 100 cities' locations (for Danish national byvejr forecasts). Moreover, we can assume that the same method can be used in other geographical areas. The evaluation for other domains (with a focus on Greenland and Nordic countries) is planned. In addition, a similar approach might be also tested for statistical correction of concentrations of chemical species, but such approach will require additional elaboration and evaluation.

  5. Automatic air and surface temperature measure by IR thermography with perspective correction

    NASA Astrophysics Data System (ADS)

    Bison, Paolo G.; Bressan, Chiara; Grinzato, Ermanno G.; Marinetti, Sergio

    1993-05-01

    Large building quantitative inspection needs both automatic correction of perspective distortion and precise air and surface temperature measurement. Unfortunately these operations are heavily time consuming if performed manually by a human operator. We present a dedicated algorithm devoted to this task. The procedure first of all detects suitable reference structures put in the field of view, by means of a visual image processing and identifies the 3D position of the wall. The second step matches the thermogram with the visual image of the object. The third step performs an inverse perspective projection applying a thermal camera model, the output is a corrected radiance field. The fourth step measures the air temperature on the reference and the surface temperature map. The surface temperature can be obtained by absolute, relative or differential methods mainly depending on object emissivity value and its spatial distribution.

  6. Correction of detector nonlinearity in Fourier transform spectroscopy with a low-temperature blackbody.

    PubMed

    Fiedler, Lars; Newman, Stuart; Bakan, Stephan

    2005-09-01

    The nonlinearity of a mercury cadmium telluride photoconductive detector, an integral part of a modified commercial interferometer used for airborne research, has been analyzed and evaluated against a number of correction schemes. A high-quality blackbody with accurate temperature control has been used as a stable and well-characterized radiation source. The detector nonlinearity was established as a function of scene temperature between 194 and 263 K. Second- and third-order corrections to the measured interferogram have been tested by analyzing the measured signal both within and outside the spectral response region of the detector. A combined correction scheme is proposed that best represents the real nonlinear response of the detector. PMID:16149357

  7. OBSERVATIONS OF SIMILARITY THEORY STABILITY CORRECTION TERMS FOR MOMENTUM AND TEMPERATURE, OVER AGRICULTURAL FIELDS AND FORESTS.

    EPA Science Inventory

    Many observations of temperature and wind speed profiles have been taken over "ideal" terrain and analyzed to develop the stability correction terms which are commonly used in the application of similarity theory. Fewer observations have been taken and analyzed in this manner ov...

  8. An improved method for correction of air temperature measured using different radiation shields

    NASA Astrophysics Data System (ADS)

    Cheng, Xinghong; Su, Debin; Li, Deping; Chen, Lu; Xu, Wenjing; Yang, Meilin; Li, Yongcheng; Yue, Zhizhong; Wang, Zijing

    2014-11-01

    The variation of air temperature measurement errors using two different radiation shields (DTR502B Vaisala, Finland, and HYTFZ01, Huayun Tongda Satcom, China) was studied. Datasets were collected in the field at the Daxing weather station in Beijing from June 2011 to May 2012. Most air temperature values obtained with these two commonly used radiation shields were lower than the reference records obtained with the new Fiber Reinforced Polymers (FRP) Stevenson screen. In most cases, the air temperature errors when using the two devices were smaller on overcast and rainy days than on sunny days; and smaller when using the imported rather than the Chinese shield. The measured errors changed sharply at sunrise and sunset, and reached maxima at noon. Their diurnal variation characteristics were, naturally, related to changes in solar radiation. The relationships between the record errors, global radiation, and wind speed were nonlinear. An improved correction method was proposed based on the approach described by Nakamura and Mahrt (2005) (NM05), in which the impact of the solar zenith angle (SZA) on the temperature error is considered and extreme errors due to changes in SZA can be corrected effectively. Measurement errors were reduced significantly after correction by either method for both shields. The error reduction rate using the improved correction method for the Chinese and imported shields were 3.3% and 40.4% higher than those using the NM05 method, respectively.

  9. Implementation of Coupled Skin Temperature Analysis and Bias Correction in a Global Atmospheric Data Assimilation System

    NASA Technical Reports Server (NTRS)

    Radakovich, Jon; Bosilovich, M.; Chern, Jiun-dar; daSilva, Arlindo

    2004-01-01

    The NASA/NCAR Finite Volume GCM (fvGCM) with the NCAR CLM (Community Land Model) version 2.0 was integrated into the NASA/GMAO Finite Volume Data Assimilation System (fvDAS). A new method was developed for coupled skin temperature assimilation and bias correction where the analysis increment and bias correction term is passed into the CLM2 and considered a forcing term in the solution to the energy balance. For our purposes, the fvDAS CLM2 was run at 1 deg. x 1.25 deg. horizontal resolution with 55 vertical levels. We assimilate the ISCCP-DX (30 km resolution) surface temperature product. The atmospheric analysis was performed 6-hourly, while the skin temperature analysis was performed 3-hourly. The bias correction term, which was updated at the analysis times, was added to the skin temperature tendency equation at every timestep. In this presentation, we focus on the validation of the surface energy budget at the in situ reference sites for the Coordinated Enhanced Observation Period (CEOP). We will concentrate on sites that include independent skin temperature measurements and complete energy budget observations for the month of July 2001. In addition, MODIS skin temperature will be used for validation. Several assimilations were conducted and preliminary results will be presented.

  10. Skin Temperature Analysis and Bias Correction in a Coupled Land-Atmosphere Data Assimilation System

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Radakovich, Jon D.; daSilva, Arlindo; Todling, Ricardo; Verter, Frances

    2006-01-01

    In an initial investigation, remotely sensed surface temperature is assimilated into a coupled atmosphere/land global data assimilation system, with explicit accounting for biases in the model state. In this scheme, an incremental bias correction term is introduced in the model's surface energy budget. In its simplest form, the algorithm estimates and corrects a constant time mean bias for each gridpoint; additional benefits are attained with a refined version of the algorithm which allows for a correction of the mean diurnal cycle. The method is validated against the assimilated observations, as well as independent near-surface air temperature observations. In many regions, not accounting for the diurnal cycle of bias caused degradation of the diurnal amplitude of background model air temperature. Energy fluxes collected through the Coordinated Enhanced Observing Period (CEOP) are used to more closely inspect the surface energy budget. In general, sensible heat flux is improved with the surface temperature assimilation, and two stations show a reduction of bias by as much as 30 Wm(sup -2) Rondonia station in Amazonia, the Bowen ratio changes direction in an improvement related to the temperature assimilation. However, at many stations the monthly latent heat flux bias is slightly increased. These results show the impact of univariate assimilation of surface temperature observations on the surface energy budget, and suggest the need for multivariate land data assimilation. The results also show the need for independent validation data, especially flux stations in varied climate regimes.

  11. 75 FR 5536 - Pipeline Safety: Control Room Management/Human Factors, Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-03

    ... . SUPPLEMENTARY INFORMATION: On December 3, 2009, PHMSA published a final rule in the Federal Register (74 FR... Safety: Control Room Management/Human Factors, Correction AGENCY: Pipeline and Hazardous Materials Safety... Regulations to address human factors and other aspects of control room management for pipelines...

  12. Correction of temperature influence on the wind retrieval from a mobile Rayleigh Doppler lidar

    NASA Astrophysics Data System (ADS)

    Zhao, Ruo-Can; Xia, Hai-Yun; Dou, Xian-Kang; Sun, Dong-Song; Han, Yu-Li; Shangguan, Ming-Jia; Guo, Jie; Shu, Zhi-Feng

    2015-02-01

    A mobile Rayleigh Doppler lidar based on double-edge technique is implemented for simultaneously observing wind and temperature at heights of 15 km-60 km away from ground. Before the inversion of the Doppler shift due to wind, the Rayleigh response function should be calculated, which is a convolution of the laser spectrum, Rayleigh backscattering function, and the transmission function of the Fabry-Perot interferometer used as the frequency discriminator in the lidar. An analysis of the influence of the temperature on the accuracy of the line-of-sight winds shows that real-time temperature profiles are needed because the bandwidth of the Rayleigh backscattering function is temperature-dependent. An integration method is employed in the inversion of the temperature, where the convergence of this method and the high signal-to-noise ratio below 60 km ensure the accuracy and precision of the temperature profiles inverted. Then, real-time and on-site temperature profiles are applied to correct the wind instead of using temperature profiles from a numerical prediction system or atmosphere model. The corrected wind profiles show satisfactory agreement with the wind profiles acquired from radiosondes, proving the reliability of the method. Project supported by the National Natural Science Foundation of China (Grant Nos. 41174130, 41174131, 41274151, and 41304123).

  13. Elevation correction of ERA-Interim temperature data in complex terrain

    NASA Astrophysics Data System (ADS)

    Gao, L.; Bernhardt, M.; Schulz, K.

    2012-12-01

    Air temperature controls a large variety of environmental processes, and is an essential input parameter for land surface models, for example in hydrology, ecology and climatology. However, meteorological networks, which can provide the necessary information, are commonly sparse in complex terrains, especially in high mountainous regions. In order to provide temperature data in an adequate temporal and spatial resolution for local scale applications a new elevation correction method has been developed that is able to downscale 3-hourly ERA-Interim temperature data. The scheme is based on model internal vertical lapse rates derived from different ERA-Interim pressure levels and has been validated for twelve meteorological stations in the German and Swiss Alps. The method was also compared with two other statistical, lapse rate based correction approaches. The results indicate that the use of model internal ERA-Interim lapse rates can significantly improve the downscaling performance when compared to the standard procedure of using fixed lapse rates.

  14. Communication: The effect of dispersion corrections on the melting temperature of liquid water

    NASA Astrophysics Data System (ADS)

    Yoo, Soohaeng; Xantheas, Sotiris S.

    2011-03-01

    The melting temperature (Tm) of liquid water with the Becke-Lee-Yang-Parr (BLYP) density functional including dispersion corrections (BLYP-D) and the Thole-type, version 3 (TTM3-F) ab-initio based flexible, polarizable classical potential is reported via constant pressure and constant enthalpy (NPH) molecular dynamics simulations of an ice Ih-liquid coexisting system. Dispersion corrections to BLYP lower Tm to about 360 K, a large improvement over the value of Tm > 400 K previously obtained with the original BLYP functional under the same simulation conditions. For TTM3-F, Tm = 248 K from classical molecular dynamics simulations.

  15. Temperature corrected transepithelial electrical resistance (TEER) measurement to quantify rapid changes in paracellular permeability.

    TOXLINE Toxicology Bibliographic Information

    Blume LF; Denker M; Gieseler F; Kunze T

    2010-01-01

    Determining the transepithelial electrical resistance (TEER) is a widely used method to functionally analyze tight junction dynamics in cell culture models of physiological barriers. Changes in temperature are known to have strong effects on TEER and can pose problems during the process of TEER measurements in cell culture vessels, complicating comparisons of TEER data across different experiments and studies. Here, we set out to devise a strategy to obtain temperature-independent TEER values based on the physical correlation between parameters such as TEER, temperature, medium viscosity and pore size of the cell culture inserts. By measuring the impact of temperature and different electrode types on TEER measurements on Caco-2 and HPDE (normal human pancreatic ductal epithelium) monolayers, we were able to derive a mathematical method that is suitable for the correction of TEER values for temperature changes. Applying this method to raw TEER values yields temperature-corrected TEER (tcTEER) values. Validity of tcTEER was demonstrated by showing a direct correlation with permeability of monolayers as determined by flux of RITC dextran. Taken together, the mathematical solution presented here allows for a simple and accurate determination of paracellular permeability independent of temperature variation during the process of TEER recording.

  16. Temperature corrected transepithelial electrical resistance (TEER) measurement to quantify rapid changes in paracellular permeability.

    PubMed

    Blume, L-F; Denker, M; Gieseler, F; Kunze, T

    2010-01-01

    Determining the transepithelial electrical resistance (TEER) is a widely used method to functionally analyze tight junction dynamics in cell culture models of physiological barriers. Changes in temperature are known to have strong effects on TEER and can pose problems during the process of TEER measurements in cell culture vessels, complicating comparisons of TEER data across different experiments and studies. Here, we set out to devise a strategy to obtain temperature-independent TEER values based on the physical correlation between parameters such as TEER, temperature, medium viscosity and pore size of the cell culture inserts. By measuring the impact of temperature and different electrode types on TEER measurements on Caco-2 and HPDE (normal human pancreatic ductal epithelium) monolayers, we were able to derive a mathematical method that is suitable for the correction of TEER values for temperature changes. Applying this method to raw TEER values yields temperature-corrected TEER (tcTEER) values. Validity of tcTEER was demonstrated by showing a direct correlation with permeability of monolayers as determined by flux of RITC dextran. Taken together, the mathematical solution presented here allows for a simple and accurate determination of paracellular permeability independent of temperature variation during the process of TEER recording. PMID:20187574

  17. Equivalence of computer codes for calculation of coincidence summing correction factors.

    PubMed

    Vidmar, T; Capogni, M; Hult, M; Hurtado, S; Kastlander, J; Lutter, G; Lpy, M-C; Martinkovi?, J; Ramebck, H; Sima, O; Tzika, F; Vidmar, G

    2014-05-01

    The aim of the study was to check for equivalence of computer codes that can perform calculations of true coincidence summing correction factors. All calculations were performed for a set of well-defined detector and sample parameters, without any reference to empirical data. For a p-type detector model the application of different codes resulted in satisfactory agreement in the calculated correction factors. For high-efficiency geometries in combination with an n-type detector and a radionuclide emitting abundant X-rays the results were scattered. PMID:24332343

  18. New look at displacement factor and point of measurement corrections in ionization chamber dosimetry

    SciTech Connect

    Awschalom, M.; Rosenberg, I.; Ten Haken, R.K.

    1983-01-01

    A new technique is presented for determination of the effective point of measurement when cavity ionization chambers are used to measure the absorbed dose due to ionizing radiation in a dense medium. An algorithm is derived relating the effective point of measurement to the displacement correction factor. This algorithm relates variations of the displacement factor to the radiation field gradient. The technique is applied to derive the magnitudes of the corrections for several chambers in a p(66)Be(49) neutron therapy beam. 30 references, 4 figures, 1 table.

  19. Equivalence of computer codes for calculation of coincidence summing correction factors - Part II.

    PubMed

    Vidmar, T; Camp, A; Hurtado, S; Jäderström, H; Kastlander, J; Lépy, M-C; Lutter, G; Ramebäck, H; Sima, O; Vargas, A

    2016-03-01

    The aim of this study was to check for equivalence of computer codes that are capable of performing calculations of true coincidence summing (TCS) correction factors. All calculations were performed for a set of well-defined detector parameters, sample parameters and decay scheme data. The studied geometry was a point source of (133)Ba positioned directly on the detector window of a low-energy (n-type) detector. Good agreement was established between the TCS correction factors computed by the different codes. PMID:26651169

  20. Correction factor for ablation algorithms used in corneal refractive surgery with gaussian-profile beams

    NASA Astrophysics Data System (ADS)

    Jimenez, Jose Ramn; Gonzlez Anera, Rosario; Jimnez del Barco, Luis; Hita, Enrique; Prez-Ocn, Francisco

    2005-01-01

    We provide a correction factor to be added in ablation algorithms when a Gaussian beam is used in photorefractive laser surgery. This factor, which quantifies the effect of pulse overlapping, depends on beam radius and spot size. We also deduce the expected post-surgical corneal radius and asphericity when considering this factor. Data on 141 eyes operated on LASIK (laser in situ keratomileusis) with a Gaussian profile show that the discrepancy between experimental and expected data on corneal power is significantly lower when using the correction factor. For an effective improvement of post-surgical visual quality, this factor should be applied in ablation algorithms that do not consider the effects of pulse overlapping with a Gaussian beam.

  1. Bias correction of temperature produced by the Community Climate System Model using Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Moghim, S.; Hsu, K.; Bras, R. L.

    2013-12-01

    General Circulation Models (GCMs) are used to predict circulation and energy transfers between the atmosphere and the land. It is known that these models produce biased results that will have impact on their uses. This work proposes a new method for bias correction: the equidistant cumulative distribution function-artificial neural network (EDCDFANN) procedure. The method uses artificial neural networks (ANNs) as a surrogate model to estimate bias-corrected temperature, given an identification of the system derived from GCM models output variables. A two-layer feed forward neural network is trained with observations during a historical period and then the adjusted network can be used to predict bias-corrected temperature for future periods. To capture the extreme values this method is combined with the equidistant CDF matching method (EDCDF, Li et al. 2010). The proposed method is tested with the Community Climate System Model (CCSM3) outputs using air and skin temperature, specific humidity, shortwave and longwave radiation as inputs to the ANN. This method decreases the mean square error and increases the spatial correlation between the modeled temperature and the observed one. The results indicate the EDCDFANN has potential to remove the biases of the model outputs.

  2. Correction of Proton Resonance Frequency Shift Temperature Maps for Magnetic Field Disturbances Caused by Breathing

    NASA Astrophysics Data System (ADS)

    Shmatukha, Andriy V.; Bakker, Chris J. G.

    2006-05-01

    Respiratory Induced Resonance Offset (RIRO) is a periodic disturbance of the magnetic field due to breathing. Such disturbances handicap the accuracy of the Proton Resonance Frequency Shift (PRFS) method of MRI temperature mapping in anatomies situated nearby the lungs and chest wall. In this work, we propose a method capable of minimizing errors caused by RIRO in PRFS temperature maps. In this method, a set of baseline images characterizing RIRO at a variety of respiratory cycle instants is acquired before the thermal treatment starts. During the treatment, the temperature evolution is found from two successive images. Then, the calculated temperature changes are corrected for the additional contribution caused by RIRO using the pre-treatment baseline images acquired at the identical instances of the respiratory cycle. Our method is shown to improve the accuracy and stability of PRFS temperature maps in the presence of RIRO and motion in phantom and volunteer experiments.

  3. Evaluating atmospheric correction models for retrieving surface temperatures from the AVHRR over a tallgrass prairie

    NASA Technical Reports Server (NTRS)

    Cooper, D. I.; Asrar, G.

    1989-01-01

    The effects of atmospheric attenuation on surface radiative temperatures obtained by the AVHRR over a tallgrass prairie area in the Flint Hills of Kansas are examined. Six atmospheric correction models developed primarily for sea-surface temperature studies are used to test their utility for retrieval of radiative temperatures over the land surface. An uncertainty of + or - 3.0 C was found for the AVHRR data, and used to evaluate the performance of a given model. When the difference between in situ and AVHRR surface temperatures was smaller than the uncertainty, the model was judged to be adequate. Among the six models evaluated, only the NOAA split-window model consistently adjusted the AVHRR surface temperatures within + or - 3.0 C of the in situ measurements.

  4. Factors affecting SFHR gene correction efficiency with single-stranded DNA fragment

    SciTech Connect

    Tsuchiya, Hiroyuki; Harashima, Hideyoshi; Kamiya, Hiroyuki . E-mail: hirokam@pharm.hokudai.ac.jp

    2005-11-04

    A 606-nt single-stranded (ss) DNA fragment, prepared by restriction enzyme digestion of ss phagemid DNA, improves the gene correction efficiency by 12-fold as compared with a PCR fragment, which is the conventional type of fragment used in the small fragment homologous replacement method [H. Tsuchiya, H. Harashima, H. Kamiya, Increased SFHR gene correction efficiency with sense single-stranded DNA, J. Gene Med. 7 (2005) 486-493]. To reveal the characteristic features of this gene correction with the ss DNA fragment, the effects on the gene correction in CHO-K1 cells of the chain length, 5'-phosphate, adenine methylation, and transcription were studied. Moreover, the possibility that the ss DNA fragment is integrated into the target DNA was examined with a radioactively labeled ss DNA fragment. The presence of methylated adenine, but not the 5'-phosphate, enhanced the gene correction efficiency, and the optimal length of the ss DNA fragment ({approx}600 nt) was determined. Transcription of the target gene did not affect the gene correction efficiency. In addition, the target DNA recovered from the transfected CHO-K1 cells was radioactive. The results obtained in this study indicate that length and adenine methylation were important factors affecting the gene correction efficiency, and that the ss DNA fragment was integrated into the double-stranded target DNA.

  5. QCD factorization for hadronic B decays: Proofs and higher-order corrections

    NASA Astrophysics Data System (ADS)

    Pecjak, Benjamin Dale

    Several issues related to the QCD factorization approach to exclusive hadronic B decays are discussed. This includes a proof of factorization in B ? K*gamma using the soft-collinear effective theory, and an examination of higher-order corrections to QCD factorization for two-body decays into heavy-light states, such as B ? Dpi, and light-light final states, such as B ? Kpi,pipi. The proof of factorization in B ? K*gamma is arguably the most complicated QCD factorization formula proven so far. It is shown that reparameterization invariance in the intermediate effective theory restricts the appearance of transverse momentum components and 3-particle Fock states to operators that can be absorbed into the QCD from factor. This proof also includes an extension of SCET to deal with two collinear directions. The examination of higher-order corrections to QCD factorization has implications for using this technique to extract CP violating weal; phases from data taken at the B factories. The renormalon calculus is used to calculate the b0a2s contributions to the hard scattering kernels, and also to analyze the strength of power corrections due to soft gluon exchange. It is shown that while power corrections are generally small, the higher-order perturbative contributions to the hard scattering kernels have much larger imaginary parts than those at next-to-leading order (NLO). This significantly enhances some CP asymmetries compared to the NLO results, which is an effect that would survive a two-loop calculation unless there were large multi-loop corrections not related to the b0a2s terms of the perturbative expansion.

  6. Temperature effects and corrections in volume measurements based on liquid-level detection

    SciTech Connect

    Suda, S.; Keisch, B.

    1993-08-01

    Temperature changes affect volume measurements in several ways. The dimensions of the tank, and the density and level of the liquid it contains vary with temperature. In addition, the response signal of the sensor and hence the response of the liquid-level detection device may change with temperature. Level measurement devices can be grouped according to four measurement points of reference: tip of probe, response proportional to the length of probe, top of tank, and liquid surface. This paper describes the physical principles of pressure, capacitance probe, sonic reflections, and visual scales. These are representative of the four types of liquid level detection techniques. Development of the temperature correction algorithm requires that the measurement process be clearly defined, conditions or limitations specified, and that a temperature-effects test be run. Although not difficult or necessarily time-consuming to run, good practice requires a test plan following demonstrated guidelines. Measurement control procedures for remeasurement of the process solution in the tank during normal operation can provide data to validate temperature correction algorithms.

  7. Shear Correction Factors in Creep-Damage Analysis of Beams, Plates and Shells

    NASA Astrophysics Data System (ADS)

    Altenbach, Holm; Naumenko, Konstantin

    Modern design rules for thin-walled structures which operate at elevated temperatures are based on the demand that the creep and may be the damage behaviour should be taken into account. In the last four decades various models including the scalar or tensor valued hardening and damage variables are established. These models reflect the influence of the deformation or the damage induced anisotropy on the creep response. One problem in creep analysis of thin-walled structures is the selection of the structural mechanics model which has to be adequate to the choice of the constitutive equations. Considering complex loading conditions the structural mechanics model has to reflect for instance the different constitutive behaviour in tension and compression. Below the applicability of classical engineering models for beams, plates and shells to the creep-damage analysis is discussed. It will be shown that a first improvement of the classical approach can be given within the assumptions of the first order shear deformation theory. Based on the beam equations we demonstrate that the shear correction factors have to be modified within the time-step analysis.

  8. Communication: The Effect of Dispersion Corrections on the Melting Temperature of Liquid Water

    SciTech Connect

    Yoo, Soohaeng; Xantheas, Sotiris S.

    2011-03-28

    We report the results of the melting temperature (Tm) of liquid water for the Becke-Lee- Yang-Parr (BLYP) density functional including Dispersion corrections (BLYP-D) and the TTM3-F ab-initio based classical potential via constant pressure and constant enthalpy (NPH) ensemble molecular dynamics simulations of an ice Ih-liquid coexisting system. The inclusion of dispersion corrections to BLYP lowers the melting temperature of liquid water to Tm=360 K, which is a large improvement over the value of Tm > 400 K obtained with the original BLYP functional. The ab-initio based flexible, polarizable Thole-type model (TTM3-F) produces Tm=248 K from classical molecular dynamics simulations.

  9. Characterization and Correction of Aquarius Long Term Calibration Drift Using On-Earth Brightness Temperature Refernces

    NASA Technical Reports Server (NTRS)

    Brown, Shannon; Misra, Sidharth

    2013-01-01

    The Aquarius/SAC-D mission was launched on June 10, 2011 from Vandenberg Air Force Base. Aquarius consists of an L-band radiometer and scatterometer intended to provide global maps of sea surface salinity. One of the main mission objectives is to provide monthly global salinity maps for climate studies of ocean circulation, surface evaporation and precipitation, air/sea interactions and other processes. Therefore, it is critical that any spatial or temporal systematic biases be characterized and corrected. One of the main mission requirements is to measure salinity with an accuracy of 0.2 psu on montly time scales which requires a brightness temperature stability of about 0.1K, which is a challenging requirement for the radiometer. A secondary use of the Aquarius data is for soil moisture applications, which requires brightness temperature stability at the warmer end of the brightness temperature dynamic range. Soon after launch, time variable drifts were observed in the Aquarius data compared to in-situ data from ARGO and models for the ocean surface salinity. These drifts could arise from a number of sources, including the various components of the retrieval algorithm, such as the correction for direct and reflected galactic emission, or from the instrument brightness temperature calibration. If arising from the brightness temperature calibration, they could have gain and offset components. It is critical that the nature of the drifts be understood before a suitable correction can be implemented. This paper describes the approach that was used to detect and characterize the components of the drift that were in the brightness temperature calibration using on-Earth reference targets that were independent of the ocean model.

  10. In-flight calibration of NOAA POES proton detectorsDerivation of the MEPED correction factors

    NASA Astrophysics Data System (ADS)

    Sandanger, Marit Irene; degaard, Linn-Kristine Glesnes; Nesse Tyssy, Hilde; Stadsnes, Johan; Sraas, Finn; Oksavik, Kjellmar; Aarsnes, Kjell

    2015-11-01

    The MEPED instruments on board the NOAA POES and MetOp satellites have been continuously measuring energetic particles in the magnetosphere since 1978. However, degradation of the proton detectors over time leads to an increase in the energy thresholds of the instrument and imposes great challenges to studies of long-term variability in the near-Earth space environment as well as a general quantification of the proton fluxes. By comparing monthly mean accumulated integral flux from a new and an old satellite at the same magnetic local time (MLT) and time period, we estimate the change in energy thresholds. The first 12 monthly energy spectra of the new satellite are used as a reference, and the derived monthly correction factors over a year for an old satellite show a small spread, indicating a robust calibration procedure. The method enables us to determine for the first time the correction factors also for the highest-energy channels of the proton detector. In addition, we make use of the newest satellite in orbit (MetOp-01) to find correction factors for 2013 for the NOAA 17 and MetOp-02 satellites. Without taking into account the level of degradation, the proton data from one satellite cannot be used quantitatively for more than 2 to 3 years after launch. As the electron detectors are vulnerable to contamination from energetic protons, the corrected proton measurements will be of value for electron flux measurements too. Thus, the correction factors ensure the correctness of both the proton and electron measurements.

  11. The accuracy of climate models' simulated season lengths and the effectiveness of grid scale correction factors

    DOE PAGESBeta

    Winterhalter, Wade E.

    2011-09-01

    Global climate change is expected to impact biological populations through a variety of mechanisms including increases in the length of their growing season. Climate models are useful tools for predicting how season length might change in the future. However, the accuracy of these models tends to be rather low at regional geographic scales. Here, I determined the ability of several atmosphere and ocean general circulating models (AOGCMs) to accurately simulate historical season lengths for a temperate ectotherm across the continental United States. I also evaluated the effectiveness of regional-scale correction factors to improve the accuracy of these models. I foundmore » that both the accuracy of simulated season lengths and the effectiveness of the correction factors to improve the model's accuracy varied geographically and across models. These results suggest that regional specific correction factors do not always adequately remove potential discrepancies between simulated and historically observed environmental parameters. As such, an explicit evaluation of the correction factors' effectiveness should be included in future studies of global climate change's impact on biological populations.« less

  12. The accuracy of climate models' simulated season lengths and the effectiveness of grid scale correction factors

    SciTech Connect

    Winterhalter, Wade E.

    2011-09-01

    Global climate change is expected to impact biological populations through a variety of mechanisms including increases in the length of their growing season. Climate models are useful tools for predicting how season length might change in the future. However, the accuracy of these models tends to be rather low at regional geographic scales. Here, I determined the ability of several atmosphere and ocean general circulating models (AOGCMs) to accurately simulate historical season lengths for a temperate ectotherm across the continental United States. I also evaluated the effectiveness of regional-scale correction factors to improve the accuracy of these models. I found that both the accuracy of simulated season lengths and the effectiveness of the correction factors to improve the model's accuracy varied geographically and across models. These results suggest that regional specific correction factors do not always adequately remove potential discrepancies between simulated and historically observed environmental parameters. As such, an explicit evaluation of the correction factors' effectiveness should be included in future studies of global climate change's impact on biological populations.

  13. Correction factor for continuous monitoring of wood smoke fine particulate matter

    PubMed Central

    McNamara, Marcy L.; Noonan, Curtis W.; Ward, Tony J.

    2012-01-01

    The US Environmental Protection Agency (EPA) has designated a handful of instruments as Federal Reference or Federal Equivalency Methods (FRM and FEM, respectively) for the monitoring of fine particulate matter (PM2.5). More commonly used for indoor exposure assessment studies are optical scanning devices such as the DustTrak (TSI) due to the their portability and affordability. It is recommended by the manufacturer of these instruments that a correction factor be applied when assessing source-specific conditions. In this study, DustTraks were collocated with multiple samplers in various environments in an effort to establish an indoor, wood smoke-source specific correction factor. The DustTrak was found to report PM2.5 levels on average 1.6 times higher than a filter based method in two indoor sampling programs. The DustTrak also reported indoor PM2.5 concentrations 1.7 times higher than a FRM sampler during a regional forest fire event. These real-world scenarios give a correction factor within a reasonable range of the results of a controlled laboratory experiment in which DustTraks reported PM2.5 approximately 2 times higher than a FEM. Our indoor wood smoke-specific correction factor of 1.65 will allow for DustTraks to be confidently used in quantifying PM2.5 exposures within indoor environments predominantly impacted by wood smoke. PMID:25364330

  14. Correction factor to dye-measured flow velocity under varying water and sediment discharges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dye-tracing technique was a widely used method to measure velocity of overland flow in soil erosion studies under both laboratory and field conditions. Few studies were performed to quantify the effects of sediment load on correction factor on steep slopes. The objective was to investigate the poten...

  15. Simulation of a Wireless Power Transfer System for Electric Vehicles with Power Factor Correction

    SciTech Connect

    Pickelsimer, Michael C; Tolbert, Leon M; Ozpineci, Burak; Miller, John M

    2012-01-01

    Wireless power transfer has been a popular topic of recent research. Most research has been done to address the limitations of coil-to-coil efficiency. However, little has been done to address the problem associated with the low input power factor with which the systems operate. This paper details the steps taken to analyze a wireless power transfer system from the view of the power grid under a variety of loading conditions with and without power factor correction.

  16. Power corrections in the quark-antiquark potential at finite temperature

    SciTech Connect

    Megias, E.; Arriola, E. Ruiz; Salcedo, L. L.

    2007-05-15

    A recently proposed phenomenological model, which includes nonperturbative effects from dimension two gluon condensates, is applied to analyze the available lattice data for the heavy quark free energy in the deconfined phase of quenched QCD. For large qq separations, we recover previous results for the Polyakov loop, exhibiting unequivocal power corrections in the temperature. For the qq potential at finite temperature and finite separation, we find that a good overall description of the lattice data can be achieved once the condensate is properly accounted for. In addition, the model predicts a duality between the zero temperature potential as a function of the qq separation, on the one hand, and the quark self-energy as a function of the temperature, on the other, which turns out to be satisfied to a high degree by the lattice data.

  17. Radiative recoil corrections to hyperfine splitting: Polarization insertions in the electron factor

    SciTech Connect

    Eides, M. I.; Shelyuto, V. A.

    2010-01-15

    We consider three-loop radiative recoil corrections to hyperfine splitting in muonium due to insertions of the one-loop polarization operator in the electron factor. The contribution generated by electron polarization insertions is a cubic polynomial in the large logarithm of the electron-muon mass ratio. The leading logarithm cubed and logarithm squared terms are well known for some time. We calculate all single-logarithmic and nonlogarithmic radiative recoil corrections of the order {alpha}{sup 3}(m/M)E{sub F} generated by diagrams with the electron and muon polarization insertions.

  18. Correcting gene expression data when neither the unwanted variation nor the factor of interest are observed

    PubMed Central

    Jacob, Laurent; Gagnon-Bartsch, Johann A.; Speed, Terence P.

    2016-01-01

    When dealing with large scale gene expression studies, observations are commonly contaminated by sources of unwanted variation such as platforms or batches. Not taking this unwanted variation into account when analyzing the data can lead to spurious associations and to missing important signals. When the analysis is unsupervised, e.g. when the goal is to cluster the samples or to build a corrected version of the dataset—as opposed to the study of an observed factor of interest—taking unwanted variation into account can become a difficult task. The factors driving unwanted variation may be correlated with the unobserved factor of interest, so that correcting for the former can remove the latter if not done carefully. We show how negative control genes and replicate samples can be used to estimate unwanted variation in gene expression, and discuss how this information can be used to correct the expression data. The proposed methods are then evaluated on synthetic data and three gene expression datasets. They generally manage to remove unwanted variation without losing the signal of interest and compare favorably to state-of-the-art corrections. All proposed methods are implemented in the bioconductor package RUVnormalize. PMID:26286812

  19. Many-electron QED corrections to the g factor of lithiumlike ions.

    PubMed

    Volotka, A V; Glazov, D A; Shabaev, V M; Tupitsyn, I I; Plunien, G

    2014-06-27

    A rigorous QED evaluation of the two-photon exchange corrections to the g factor of lithiumlike ions is presented. The screened self-energy corrections are calculated for the intermediate-Z region, and its accuracy for the high-Z region is essentially improved in comparison with that of previous calculations. As a result, the theoretical accuracy of the g factor of lithiumlike ions is significantly increased. The theoretical prediction obtained for the g factor of (28)Si(11+) g(th) = 2.000?889?892(8) is in an excellent agreement with the corresponding experimental value g(exp) = 2.000?889?889?9(21) [A. Wagner et al., Phys. Rev. Lett. 110, 033003 (2013). PMID:25014810

  20. Monte Carlo calculated correction factors for diodes and ion chambers in small photon fields.

    PubMed

    Czarnecki, D; Zink, K

    2013-04-21

    The application of small photon fields in modern radiotherapy requires the determination of total scatter factors Scp or field factors ?(f(clin), f(msr))(Q(clin), Q(msr)) with high precision. Both quantities require the knowledge of the field-size-dependent and detector-dependent correction factor k(f(clin), f(msr))(Q(clin), Q(msr)). The aim of this study is the determination of the correction factor k(f(clin), f(msr))(Q(clin), Q(msr)) for different types of detectors in a clinical 6 MV photon beam of a Siemens KD linear accelerator. The EGSnrc Monte Carlo code was used to calculate the dose to water and the dose to different detectors to determine the field factor as well as the mentioned correction factor for different small square field sizes. Besides this, the mean water to air stopping power ratio as well as the ratio of the mean energy absorption coefficients for the relevant materials was calculated for different small field sizes. As the beam source, a Monte Carlo based model of a Siemens KD linear accelerator was used. The results show that in the case of ionization chambers the detector volume has the largest impact on the correction factor k(f(clin), f(msr))(Q(clin), Q(msr)); this perturbation may contribute up to 50% to the correction factor. Field-dependent changes in stopping-power ratios are negligible. The magnitude of k(f(clin), f(msr))(Q(clin), Q(msr)) is of the order of 1.2 at a field size of 1 1 cm(2) for the large volume ion chamber PTW31010 and is still in the range of 1.05-1.07 for the PinPoint chambers PTW31014 and PTW31016. For the diode detectors included in this study (PTW60016, PTW 60017), the correction factor deviates no more than 2% from unity in field sizes between 10 10 and 1 1 cm(2), but below this field size there is a steep decrease of k(f(clin), f(msr))(Q(clin), Q(msr)) below unity, i.e. a strong overestimation of dose. Besides the field size and detector dependence, the results reveal a clear dependence of the correction factor on the accelerator geometry for field sizes below 1 1 cm(2), i.e. on the beam spot size of the primary electrons hitting the target. This effect is especially pronounced for the ionization chambers. In conclusion, comparing all detectors, the unshielded diode PTW60017 is highly recommended for small field dosimetry, since its correction factor k(f(clin), f(msr))(Q(clin), Q(msr)) is closest to unity in small fields and mainly independent of the electron beam spot size. PMID:23514734

  1. Radiative corrections to the Casimir Pressure under the influence of temperature and external fields

    SciTech Connect

    Robaschik, D.; Scharonhorst, K.; Wieczorek, E.

    1987-03-01

    Generalizing the quantum field theory (QFT) with boundary conditions in covariant gauge to the case of finite temperature, we develop the quantum electrodynamics (QED) with boundary conditions in the Matsubara approach as well as in the thermofield formulation. We rederive the known results of the free-field theory for the pressure and the free energy of the Casimir problem. For infinitely thin plates we calculate the radiative corrections in second-order perturbation theory at finite temperature. Thereby it turns out that the calculation in of the vacuum energy at the vanishing temperature via the Z functional is much simplier than the calculation via the energy momentum tensor. This observation allows determination of the influence of static electromagnetic fields on the Casimir problem. copyright 1987 Academic Press, Inc.

  2. Pressure and temperature effect corrections of atmospheric muon data in the Belgrade cosmic-ray station

    NASA Astrophysics Data System (ADS)

    Savi?, M.; Maleti?, D.; Jokovi?, D.; Veselinovi?, N.; Banjanac, R.; Udovi?i?, V.; Dragi?, A.

    2015-08-01

    We present results of continuous monitoring of the cosmic-ray muon intensity at the ground and shallow underground level at the Belgrade cosmic-ray station. The cosmic-ray muon measurements have been performed since 2002, by means of plastic scintillation detectors. The scintillator counts are corrected for atmospheric pressure for the whole period of measurements and, as well, for vertical temperature profile for the period of the last six years. The results are compared with other correction methods available. One-hour time series of the cosmic-ray muon intensity at the ground level are checked for correlation with European neutron monitors, with emphasis on occasional extreme solar events, e.g. Forbush decreases.

  3. A physics-based correction model for homogenizing sub-daily temperature series

    NASA Astrophysics Data System (ADS)

    Auchmann, R.; BrNnimann, S.

    2012-09-01

    A new physics-based technique for correcting inhomogeneities present in sub-daily temperature records is proposed. The approach accounts for changes in the sensor-shield characteristics that affect the energy balance dependent on ambient weather conditions (radiation, wind). An empirical model is formulated that reflects the main atmospheric processes and can be used in the correction step of a homogenization procedure. The model accounts for short- and long-wave radiation fluxes (including a snow cover component for albedo calculation) of a measurement system, such as a radiation shield. One part of the flux is further modulated by ventilation. The model requires only cloud cover and wind speed for each day, but detailed site-specific information is necessary. The final model has three free parameters, one of which is a constant offset. The three parameters can be determined, e.g., using the mean offsets for three observation times. The model is developed using the example of the change from the Wild screen to the Stevenson screen in the temperature record of Basel, Switzerland, in 1966. It is evaluated based on parallel measurements of both systems during a sub-period at this location, which were discovered during the writing of this paper. The model can be used in the correction step of homogenization to distribute a known mean step-size to every single measurement, thus providing a reasonable alternative correction procedure for high-resolution historical climate series. It also constitutes an error model, which may be applied, e.g., in data assimilation approaches.

  4. Correcting infrared satellite estimates of sea surface temperature for atmospheric water vapor attenuation

    NASA Technical Reports Server (NTRS)

    Emery, William J.; Yu, Yunyue; Wick, Gary A.; Schluessel, Peter; Reynolds, Richard W.

    1994-01-01

    A new satellite sea surface temperature (SST) algorithm is developed that uses nearly coincident measurements from the microwave special sensor microwave imager (SSM/I) to correct for atmospheric moisture attenuation of the infrared signal from the advanced very high resolution radiometer (AVHRR). This new SST algorithm is applied to AVHRR imagery from the South Pacific and Norwegian seas, which are then compared with simultaneous in situ (ship based) measurements of both skin and bulk SST. In addition, an SST algorithm using a quadratic product of the difference between the two AVHRR thermal infrared channels is compared with the in situ measurements. While the quadratic formulation provides a considerable improvement over the older cross product (CPSST) and multichannel (MCSST) algorithms, the SSM/I corrected SST (called the water vapor or WVSST) shows overall smaller errors when compared to both the skin and bulk in situ SST observations. Applied to individual AVHRR images, the WVSST reveals an SST difference pattern (CPSST-WVSST) similar in shape to the water vapor structure while the CPSST-quadratic SST difference appears unrelated in pattern to the nearly coincident water vapor pattern. An application of the WVSST to week-long composites of global area coverage (GAC) AVHRR data demonstrates again the manner in which the WVSST corrects the AVHRR for atmospheric moisture attenuation. By comparison the quadratic SST method underestimates the SST corrections in the lower latitudes and overestimates the SST in th e higher latitudes. Correlations between the AVHRR thermal channel differences and the SSM/I water vapor demonstrate the inability of the channel difference to represent water vapor in the midlatitude and high latitudes during summer. Compared against drifting buoy data the WVSST and the quadratic SST both exhibit the same general behavior with the relatively small differences with the buoy temperatures.

  5. Stress Intensity Factor Plasticity Correction for Flaws in Stress Concentration Regions

    SciTech Connect

    Friedman, E.; Wilson, W.K.

    2000-02-01

    Plasticity corrections to elastically computed stress intensity factors are often included in brittle fracture evaluation procedures. These corrections are based on the existence of a plastic zone in the vicinity of the crack tip. Such a plastic zone correction is included in the flaw evaluation procedure of Appendix A to Section XI of the ASME Boiler and Pressure Vessel Code. Plasticity effects from the results of elastic and elastic-plastic explicit flaw finite element analyses are examined for various size cracks emanating from the root of a notch in a panel and for cracks located at fillet fadii. The results of these caluclations provide conditions under which the crack-tip plastic zone correction based on the Irwin plastic zone size overestimates the plasticity effect for crack-like flaws embedded in stress concentration regions in which the elastically computed stress exceeds the yield strength of the material. A failure assessment diagram (FAD) curve is employed to graphically c haracterize the effect of plasticity on the crack driving force. The Option 1 FAD curve of the Level 3 advanced fracture assessment procedure of British Standard PD 6493:1991, adjusted for stress concentration effects by a term that is a function of the applied load and the ratio of the local radius of curvature at the flaw location to the flaw depth, provides a satisfactory bound to all the FAD curves derived from the explicit flaw finite element calculations. The adjusted FAD curve is a less restrictive plasticity correction than the plastic zone correction of Section XI for flaws embedded in plastic zones at geometric stress concentrators. This enables unnecessary conservatism to be removed from flaw evaluation procedures that utilize plasticity corrections.

  6. Thermocouple error correction for measuring the flame temperature with determination of emissivity and heat transfer coefficient.

    PubMed

    Hindasageri, V; Vedula, R P; Prabhu, S V

    2013-02-01

    Temperature measurement by thermocouples is prone to errors due to conduction and radiation losses and therefore has to be corrected for precise measurement. The temperature dependent emissivity of the thermocouple wires is measured by the use of thermal infrared camera. The measured emissivities are found to be 20%-40% lower than the theoretical values predicted from theory of electromagnetism. A transient technique is employed for finding the heat transfer coefficients for the lead wire and the bead of the thermocouple. This method does not require the data of thermal properties and velocity of the burnt gases. The heat transfer coefficients obtained from the present method have an average deviation of 20% from the available heat transfer correlations in literature for non-reacting convective flow over cylinders and spheres. The parametric study of thermocouple error using the numerical code confirmed the existence of a minimum wire length beyond which the conduction loss is a constant minimal. Temperature of premixed methane-air flames stabilised on 16 mm diameter tube burner is measured by three B-type thermocouples of wire diameters: 0.15 mm, 0.30 mm, and 0.60 mm. The measurements are made at three distances from the burner tip (thermocouple tip to burner tip/burner diameter = 2, 4, and 6) at an equivalence ratio of 1 for the tube Reynolds number varying from 1000 to 2200. These measured flame temperatures are corrected by the present numerical procedure, the multi-element method, and the extrapolation method. The flame temperatures estimated by the two-element method and extrapolation method deviate from numerical results within 2.5% and 4%, respectively. PMID:23464237

  7. Determination of ion recombination correction factors for a liquid ionization chamber in megavoltage photon beams

    NASA Astrophysics Data System (ADS)

    Choi, Sang Hyoun; Kim, Kum-Bae; Ji, Young Hoon; Kim, Chan Hyeong; Kim, Seonghoon; Huh, Hyun Do

    2015-05-01

    The aim of this study is to determine the ion recombination correction factor for a liquid ionization chamber in a high energy photon beam by using our experimental method. The ion recombination correction factors were determined by using our experimental method and were compared with theoretical and experimental methods proposed by using the theoretical method (Greening, Johansson) and the two-dose rate method in a cobalt beam and a high energy photon beam. In order to apply the liquid ionization chamber in a reference and small field dosimetry, we acquired the absorbed dose to water correction coefficient, the beam quality correction factor, and the influence quantities for the microLion chamber according to the TRS-398 protocol and applied the results to a high energy photon beam used in clinical fields. As a result, our experimental method for ion recombination in a cobalt beam agreed with the results from the heoretical method (Greening theory) better than it did with the results from the two-dose rate method. For high energy photon beams, the two-dose rate and our experimental methods were in good agreement, less than 2% deviation, while the theoretical general collection efficiency (Johansson et al.) deviated greatly from the experimental values. When we applied the factors for the absorbed dose to water measurement, the absorbed dose to water for the microLion chamber was in good agreement, within 1%, compared with the values for the PTW 30013 chamber in 6 and 10 MV Clinac iX and 6 and 15 MV Oncor impression. With these results, not only can the microLion ionization chamber be used to measure the absorbed dose to water in a reference condition, it can also be used to a the chamber for small, non-standard field dosimetry.

  8. Totem-Pole Power-Factor-Correction Converter under Critical-Conduction-Mode Interleaved Operation

    NASA Astrophysics Data System (ADS)

    Firmansyah, Eka; Tomioka, Satoshi; Abe, Seiya; Shoyama, Masahito; Ninomiya, Tamotsu

    This paper proposes a new power-factor-correction (PFC) topology, and explains its operation principle, its control mechanism, related application problems followed by experimental results. In this proposed topology, critical-conduction-mode (CRM) interleaved technique is applied to a bridgeless PFC in order to achieve high efficiency by combining benefits of each topology. This application is targeted toward low to middle power applications that normally employs continuous-conduction-mode boost converter.

  9. Born-corrections to weak lensing of the cosmic microwave background temperature and polarization anisotropies

    NASA Astrophysics Data System (ADS)

    Hagstotz, Steffen; Schäfer, Björn Malte; Merkel, Philipp M.

    2015-11-01

    Many weak-lensing calculations make use of the Born approximation where the light ray is approximated by a straight path. We examine the effect of Born-corrections for lensing of the cosmic microwave background (CMB) in an analytical approach by taking perturbative corrections to the geodesic into account. The resulting extra power in the lensing potential spectrum is comparable to the power generated by non-linear structure formation and affects especially the polarization spectra, leading to relative changes of the order of 10-3 for the E-mode spectrum and several per cent on all scales to the B-mode spectrum. In contrast, there is only little change of spectra involving the CMB temperature. Additionally, the corrections excite one more degree of freedom resulting in a deflection component which cannot be described as a gradient of the lensing potential as it is related to image rotation in lens-lens coupling. We estimate the magnitude of this effect on the CMB spectra and find it to be negligible.

  10. Estimation of absolute water surface temperature based on atmospherically corrected thermal infrared multispectral scanner digital data

    NASA Technical Reports Server (NTRS)

    Anderson, James E.

    1986-01-01

    Airborne remote sensing systems, as well as those on board Earth orbiting satellites, sample electromagnetic energy in discrete wavelength regions and convert the total energy sampled into data suitable for processing by digital computers. In general, however, the total amount of energy reaching a sensor system located at some distance from the target is composed not only of target related energy, but, in addition, contains a contribution originating from the atmosphere itself. Thus, some method must be devised for removing or at least minimizing the effects of the atmosphere. The LOWTRAN-6 Program was designed to estimate atmospheric transmittance and radiance for a given atmospheric path at moderate spectral resolution over an operational wavelength region from 0.25 to 28.5 microns. In order to compute the Thermal Infrared Multispectral Scanner (TIMS) digital values which were recorded in the absence of the atmosphere, the parameters derived from LOWTRAN-6 are used in a correction equation. The TIMS data were collected at 1:00 a.m. local time on November 21, 1983, over a recirculating cooling pond for a power plant in southeastern Mississippi. The TIMS data were analyzed before and after atmospheric corrections were applied using a band ratioing model to compute the absolute surface temperature of various points on the power plant cooling pond. The summarized results clearly demonstrate the desirability of applying atmospheric corrections.

  11. Factors Associated with Recidivism among Corrections-Based Treatment Participants in Rural and Urban Areas.

    PubMed

    Staton-Tindall, Michele; Harp, Kathi L H; Winston, Erin; Webster, J Matthew; Pangburn, Kevin

    2015-09-01

    The majority of corrections-based treatment outcome studies focus on individuals paroling to urban areas; thus there is a significant gap in the literature on outcomes, including recidivism, among individuals paroling to non-urban and rural communities. This study examines differences in factors associated with recidivism among former corrections-based treatment participants living in urban and rural communities following release. Analyses focused on secondary data collected from treatment participants in one southeastern state over a four year period between July 2006 and June 2010 including both baseline (treatment intake) and follow-up data (12-months post-release). Findings indicated that individuals in urban areas were 2.4 times more likely to recidivate than rural individuals. Other factors identified in separate rural and urban analyses also emerged as significant predictors in the overall model including age, gender, race, employment and drug use. Overall, these findings suggest that corrections-based treatment participants living in urban and rural areas following release may share similar risk factors for recidivism. However, rural areas may be protective for returning to custody despite the presence of some of these risks. PMID:25858761

  12. Analysis, compensation, and correction of temperature effects on FBG strain sensors

    NASA Astrophysics Data System (ADS)

    Haber, T. C.; Ferguson, S.; Guthrie, D.; Graver, T. W.; Soller, B. J.; Mendez, Alexis

    2013-05-01

    One of the most common fiber optic sensor (FOS) types used are fiber Bragg gratings (FBG), and the most frequently measured parameter is strain. Hence, FBG strain sensors are one of the most prevalent FOS devices in use today in structural sensing and monitoring in civil engineering, aerospace, marine, oil and gas, composites and smart structure applications. However, since FBGs are simultaneously sensitive to both temperature and strain, it becomes essential to utilize sensors that are either fully temperature insensitive or, alternatively, properly temperature compensated to avoid erroneous measurements. In this paper, we introduce the concept of measured "total strain", which is inherent and unique to optical strain sensors. We review and analyze the temperature and strain sensitivities of FBG strain sensors and decompose the total measured strain into thermal and non-thermal components. We explore the differences between substrate CTE and System Thermal Response Coefficients, which govern the type and quality of thermal strain decomposition analysis. Finally, we present specific guidelines to achieve proper temperature-insensitive strain measurements by combining adequate installation, sensor packaging and data correction techniques.

  13. Method and apparatus for correcting eddy current signal voltage for temperature effects

    DOEpatents

    Kustra, Thomas A. (N. Huntingdon, PA); Caffarel, Alfred J. (Pittsburgh, PA)

    1990-01-01

    An apparatus and method for measuring physical characteristics of an electrically conductive material by the use of eddy-current techniques and compensating measurement errors caused by changes in temperature includes a switching arrangement connected between primary and reference coils of an eddy-current probe which allows the probe to be selectively connected between an eddy current output oscilloscope and a digital ohm-meter for measuring the resistances of the primary and reference coils substantially at the time of eddy current measurement. In this way, changes in resistance due to temperature effects can be completely taken into account in determining the true error in the eddy current measurement. The true error can consequently be converted into an equivalent eddy current measurement correction.

  14. Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

    NASA Technical Reports Server (NTRS)

    Blankenship, Clay; Zavodsky, Brad; Blackwell, William

    2014-01-01

    Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. This paper will describe the bias correction technique and results from forecasts evaluated by validation against a Total Precipitable Water (TPW) product from CIRA and against Global Forecast System (GFS) analyses.

  15. Electron fluence correction factors for conversion of dose in plastic to dose in water.

    PubMed

    Ding, G X; Rogers, D W; Cygler, J E; Mackie, T R

    1997-02-01

    In radiation dosimetry protocols, plastic is allowed as a phantom material for the determination of absorbed dose to water in electron beams. The electron fluence correction factor is needed in conversion of dose measured in plastic to dose in water. There are large discrepancies among recommended values as well as measured values of electron fluence correction factors when polystyrene is used as a phantom material. Using the Monte Carlo technique, we have calculated electron fluence correction factors for incident clinical beam energies between 5 and 50 MeV as a function of depth for clear polystyrene, white polystyrene and PMMA phantom materials and compared the results with those recommended in protocols as well as experimental values from published data. In the Monte Carlo calculations, clinical beams are simulated using the EGS4 user-code BEAM for a variety of medical accelerators. The study shows that our calculated fluence correction factor, phi pw, is a function of depth and incident beam energy Eo with little dependence on other aspects of beam quality. However the phi pw values at dmax are indirectly influenced by the beam quality since they vary with depth and dmax also varies with the beam quality. Calculated phi pw values at dmax are in a range of 1.005-1.045 for a clear polystyrene phantom, 1.005-1.038 for a white polystyrene phantom and 0.996-1.016 for a PMMA phantom. Our values of phi pw are about 1-2% higher than those determined according to the AAPM TG-25 protocol at dmax for clear or white polystyrene. Our calculated values of phi pw also explain some of the variations of measured data because of its depth dependence. A simple formula is derived which gives the electron fluence correction factor phi pw as a function of R50 at dmax or at the depth of 0.6R50-0.1 for any clinical electron beam with energy between 5 and 25 MeV for three plastics: clear polystyrene, white polystyrene and PMMA. The study also makes a careful distinction between phi pw and the corresponding IAEA Code of Practice quantity, hm. PMID:9048356

  16. Correction factors for source strength determination in HDR brachytherapy using the in-phantom method.

    PubMed

    Ubrich, Frank; Wulff, Jrg; Engenhart-Cabillic, Rita; Zink, Klemens

    2014-05-01

    For the purpose of clinical source strength determination for HDR brachytherapy sources, the German society for Medical Physics (DGMP) recommends in their report 13 the usage of a solid state phantom (Krieger-phantom) with a thimble ionization chamber. In this work, the calibration chain for the determination of the reference air-kerma rate Ka,100 and reference dose rate to waterDw,1 by ionization chamber measurement in the Krieger-phantom was modeled via Monte Carlo simulations. These calculations were used to determine global correction factors k(tot), which allows a user to directly convert the reading of an ionization chamber calibrated in terms of absorbed dose to water, into the desired quantity Ka,100 or Dw,1. The factor k(tot) was determined for four available (192)Ir sources and one (60)Co source with three different thimble ionization chambers. Finally, ionization chamber measurements on three ?Selectron V2 HDR sources within the Krieger-phantom were performed and Ka,100 was determined according to three different methods: 1) using a calibration factor in terms of absorbed dose to water with the global correction factor [Formula: see text] according DGMP 13 2) using a global correction factor calculated via Monte Carlo 3) using a direct reference air-kerma rate calibration factor determined by the national metrology institute PTB. The comparison of Monte Carlo based [Formula: see text] with those from DGMP 13 showed that the DGMP data were systematically smaller by about 2-2.5%. The experimentally determined [Formula: see text] , based on the direct Ka,100 calibration were also systematically smaller by about 1.5%. Despite of these systematical deviations, the agreement of the different methods was in almost all cases within the 1? level of confidence of the interval of their respective uncertainties in a Gaussian distribution. The application of Monte Carlo based [Formula: see text] for the determination of Ka,100 for three ?Selectron V2 sources revealed the smallest deviation to the manufacturer's source certificate. With the calculated [Formula: see text] for a (60)Co source, the user is now able to accurately determine Ka,100 of a HDR (60)Co source via in-phantom measurement. Moreover, using the presented global correction factor [Formula: see text] , the user is able to determine the future source specification quantity Dw,1 with the same in-phantom setup. PMID:24021956

  17. Perturbative corrections to Λ b → Λ form factors from QCD light-cone sum rules

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Ming; Shen, Yue-Long

    2016-02-01

    We compute radiative corrections to Λ b → Λ from factors, at next-to-leading logarithmic accuracy, from QCD light-cone sum rules with Λ b -baryon distribution amplitudes. Employing the diagrammatic approach factorization of the vacuum-to-Λ b -baryon correlation function is justified at leading power in Λ /m b , with the aid of the method of regions. Hard functions entering the factorization formulae are identical to the corresponding matching coefficients of heavy-to-light currents from QCD onto soft-collinear effective theory. The universal jet function from integrating out the hard-collinear fluctuations exhibits richer structures compared with the one involved in the factorization expressions of the vacuum-to- B-meson correlation function. Based upon the QCD resummation improved sum rules we observe that the perturbative corrections at {O}({α}_s) shift the Λ b → Λ from factors at large recoil significantly and the dominant contribution originates from the next-to-leading order jet function instead of the hard coefficient functions. Having at hand the sum rule predictions for the Λ b → Λ from factors we further investigate several decay observables in the electro-weak penguin Λ b → Λ ℓ + ℓ - transitions in the factorization limit (i.e., ignoring the "non-factorizable" hadronic effects which cannot be expressed in terms of the Λ b → Λ from factors), including the invariant mass distribution of the lepton pair, the forward-backward asymmetry in the dilepton system and the longitudinal polarization fraction of the leptonic sector.

  18. SU-E-T-469: A Practical Approach for the Determination of Small Field Output Factors Using Published Monte Carlo Derived Correction Factors

    SciTech Connect

    Calderon, E; Siergiej, D

    2014-06-01

    Purpose: Output factor determination for small fields (less than 20 mm) presents significant challenges due to ion chamber volume averaging and diode over-response. Measured output factor values between detectors are known to have large deviations as field sizes are decreased. No set standard to resolve this difference in measurement exists. We observed differences between measured output factors of up to 14% using two different detectors. Published Monte Carlo derived correction factors were used to address this challenge and decrease the output factor deviation between detectors. Methods: Output factors for Elekta's linac-based stereotactic cone system were measured using the EDGE detector (Sun Nuclear) and the A16 ion chamber (Standard Imaging). Measurements conditions were 100 cm SSD (source to surface distance) and 1.5 cm depth. Output factors were first normalized to a 10.4 cm 10.4 cm field size using a daisy-chaining technique to minimize the dependence of field size on detector response. An equation expressing the relation between published Monte Carlo correction factors as a function of field size for each detector was derived. The measured output factors were then multiplied by the calculated correction factors. EBT3 gafchromic film dosimetry was used to independently validate the corrected output factors. Results: Without correction, the deviation in output factors between the EDGE and A16 detectors ranged from 1.3 to 14.8%, depending on cone size. After applying the calculated correction factors, this deviation fell to 0 to 3.4%. Output factors determined with film agree within 3.5% of the corrected output factors. Conclusion: We present a practical approach to applying published Monte Carlo derived correction factors to measured small field output factors for the EDGE and A16 detectors. Using this method, we were able to decrease the percent deviation between both detectors from 14.8% to 3.4% agreement.

  19. Water temperature-influential factors, field measurement, and data presentation

    USGS Publications Warehouse

    Stevens, Herbert H.; Ficke, John F.; Smoot, George F.

    1975-01-01

    This manual contains suggested procedures for collecting and reporting of water-temperature data on streams, lakes and reservoirs, estuaries, and ground water. Among the topics discussed are the selection of equipment and measuring sites, objectives and accuracy of measurements, and data processing and presentation. Background information on the influence of temperature on water quality and the factors influencing water temperature are also presented.

  20. Monte Carlo calculations of correction factors for plastic phantoms in clinical photon and electron beam dosimetry

    SciTech Connect

    Araki, Fujio; Hanyu, Yuji; Fukuoka, Miyoko; Matsumoto, Kenji; Okumura, Masahiko; Oguchi, Hiroshi

    2009-07-15

    The purpose of this study is to calculate correction factors for plastic water (PW) and plastic water diagnostic-therapy (PWDT) phantoms in clinical photon and electron beam dosimetry using the EGSnrc Monte Carlo code system. A water-to-plastic ionization conversion factor k{sub pl} for PW and PWDT was computed for several commonly used Farmer-type ionization chambers with different wall materials in the range of 4-18 MV photon beams. For electron beams, a depth-scaling factor c{sub pl} and a chamber-dependent fluence correction factor h{sub pl} for both phantoms were also calculated in combination with NACP-02 and Roos plane-parallel ionization chambers in the range of 4-18 MeV. The h{sub pl} values for the plane-parallel chambers were evaluated from the electron fluence correction factor {phi}{sub pl}{sup w} and wall correction factors P{sub wall,w} and P{sub wall,pl} for a combination of water or plastic materials. The calculated k{sub pl} and h{sub pl} values were verified by comparison with the measured values. A set of k{sub pl} values computed for the Farmer-type chambers was equal to unity within 0.5% for PW and PWDT in photon beams. The k{sub pl} values also agreed within their combined uncertainty with the measured data. For electron beams, the c{sub pl} values computed for PW and PWDT were from 0.998 to 1.000 and from 0.992 to 0.997, respectively, in the range of 4-18 MeV. The {phi}{sub pl}{sup w} values for PW and PWDT were from 0.998 to 1.001 and from 1.004 to 1.001, respectively, at a reference depth in the range of 4-18 MeV. The difference in P{sub wall} between water and plastic materials for the plane-parallel chambers was 0.8% at a maximum. Finally, h{sub pl} values evaluated for plastic materials were equal to unity within 0.6% for NACP-02 and Roos chambers. The h{sub pl} values also agreed within their combined uncertainty with the measured data. The absorbed dose to water from ionization chamber measurements in PW and PWDT plastic materials corresponds to that in water within 1%. Both phantoms can thus be used as a substitute for water for photon and electron dosimetry.

  1. Determination of small-field correction factors for cylindrical ionization chambers using a semiempirical method

    NASA Astrophysics Data System (ADS)

    Park, Kwangwoo; Bak, Jino; Park, Sungho; Choi, Wonhoon; Park, Suk Won

    2016-02-01

    A semiempirical method based on the averaging effect of the sensitive volumes of different air-filled ionization chambers (ICs) was employed to approximate the correction factors for beam quality produced from the difference in the sizes of the reference field and small fields. We measured the output factors using several cylindrical ICs and calculated the correction factors using a mathematical method similar to deconvolution; in the method, we modeled the variable and inhomogeneous energy fluence function within the chamber cavity. The parameters of the modeled function and the correction factors were determined by solving a developed system of equations as well as on the basis of the measurement data and the geometry of the chambers. Further, Monte Carlo (MC) computations were performed using the Monaco® treatment planning system to validate the proposed method. The determined correction factors (k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} ) were comparable to the values derived from the MC computations performed using Monaco®. For example, for a 6 MV photon beam and a field size of 1  ×  1 cm2, k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} was calculated to be 1.125 for a PTW 31010 chamber and 1.022 for a PTW 31016 chamber. On the other hand, the k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} values determined from the MC computations were 1.121 and 1.031, respectively; the difference between the proposed method and the MC computation is less than 2%. In addition, we determined the k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} values for PTW 30013, PTW 31010, PTW 31016, IBA FC23-C, and IBA CC13 chambers as well. We devised a method for determining k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} from both the measurement of the output factors and model-based mathematical computation. The proposed method can be useful in case the MC simulation would not be applicable for the clinical settings.

  2. Photon quality correction factors for ionization chambers in an epithermal neutron beam.

    PubMed

    Munck af Rosenschld, P M; Ceberg, C P; Giusti, V; Andreo, P

    2002-07-21

    Photon quality correction factors (kQy) for ionization chamber photon dosimetry in an epithermal neutron beam were determined according to a modified absorbed dose to water formalism which was extended to mixed radiation fields. We have studied two commercially available ionization chambers in the epithermal neutron beam optimized for BNCT at the facility at Studsvik, Sweden. One of the chambers is nominally neutron insensitive; a magnesium-walled detector flushed with pure argon gas (denoted by Mg/Ar). The second chamber has approximately the same sensitivity for neutrons and photons; it is considered a 'tissue equivalent' detector, with A-150 walls flushed with methane-based tissue-equivalent gas (denoted by TE/TE). The kQy-factors in epithermal neutron beams have previously been assumed to be equal to unity or estimated from measurements in clinical accelerator produced photon beams. In this work the kQy-factors have been determined from absorbed dose calculations using cavity theory together with Monte Carlo derived electron fluences obtained with the MCNP4c system for water and PMMA phantoms. The calculated quality correction factors differ substantially from unity, being in the order of 10% for the Mg/Ar detector at shallow phantom depths, and between 2 and 4% for other depths and for the TE/TE chamber. PMID:12171330

  3. Photon quality correction factors for ionization chambers in an epithermal neutron beam

    NASA Astrophysics Data System (ADS)

    Rosenschld, P. M. Munck af; Ceberg, C. P.; Giusti, V.; Andreo, P.

    2002-07-01

    Photon quality correction factors (kQ?) for ionization chamber photon dosimetry in an epithermal neutron beam were determined according to a modified absorbed dose to water formalism which was extended to mixed radiation fields. We have studied two commercially available ionization chambers in the epithermal neutron beam optimized for BNCT at the facility at Studsvik, Sweden. One of the chambers is nominally neutron insensitive; a magnesium-walled detector flushed with pure argon gas (denoted by Mg/Ar). The second chamber has approximately the same sensitivity for neutrons and photons; it is considered a 'tissue equivalent' detector, with A-150 walls flushed with methane-based tissue-equivalent gas (denoted by TE/TE). The kQ?-factors in epithermal neutron beams have previously been assumed to be equal to unity or estimated from measurements in clinical accelerator produced photon beams. In this work the kQ?-factors have been determined from absorbed dose calculations using cavity theory together with Monte Carlo derived electron fluences obtained with the MCNP4c system for water and PMMA phantoms. The calculated quality correction factors differ substantially from unity, being in the order of 10% for the Mg/Ar detector at shallow phantom depths, and between 2 and 4% for other depths and for the TE/TE chamber.

  4. Burnout among corrections-based drug treatment staff: impact of individual and organizational factors.

    PubMed

    Garner, Bryan R; Knight, Kevin; Simpson, D Dwayne

    2007-10-01

    As a result of limited budgets, many treatment programs are forced to operate for extended periods at or beyond their capacity. The resulting pressure and stress on treatment staff can be taxing and lead to serious problems, including job burnout. Although the concept of burnout within other social service professions has been broadly researched, less attention has been given to burnout among drug abuse treatment staff, especially among corrections-based drug treatment staff. The goal of this article is to extend this area of research by exploring the impact of individual factors and organizational factors on burnout. Findings revealed that although a number of factors were related to staff burnout, younger counselor age, lower adaptability, poorer clarity of agency mission, and higher stress were most significant. Ways in which treatment programs might address these issues affecting staff burnout are discussed. PMID:17615435

  5. Break Correction of Swiss Daily and Sub-Daily Temperature Series

    NASA Astrophysics Data System (ADS)

    Auchmann, Renate; Kuglitsch, Franz; Toreti, Andrea; Brnnimann, Stefan

    2014-05-01

    Many applications in climate science require high-quality, long-term data at a high temporal resolution. However, such records are often affected by artificial breaks. The challenging task of homogenizing daily and sub-daily data has only been partially addressed in recent years. Therefore, the number of available datasets providing homogeneous daily and sub-daily series is still small compared to the volume of monthly or annual data. In this study, series of daily maximum (Tmax), daily minimum (Tmin), morning (Tmorn), noon (Tnoon) and evening (Teve), and daily mean (Tmean) temperatures measured in 61 stations of the Swiss climate observation network were corrected for artificial breaks. The break detection for the above mentioned series was accomplished in a former study by using a combination of three different break detection methods. Here the previously determined breakpoints are corrected by applying the method of higher-order moments for autocorrelated data (HOMAD), which is an improved version of the higher-order moments method (HOM), providing an objective choice of regression parameters.

  6. Partial correction of murine hemophilia A with neo-antigenic murine factor VIII.

    PubMed

    Sarkar, R; Gao, G P; Chirmule, N; Tazelaar, J; Kazazian, H H

    2000-04-10

    We have previously reported a factor VIII knockout (FVIII KO) mouse model for hemophilia A. Here we demonstrate the presence of nonfunctional heavy chain factor VIII protein in the mouse, making it an excellent model for cross-reacting material (CRM)-positive hemophilia A patients, who express normal levels of a dysfunctional FVIII protein. We attempted to correct these mice phenotypically by transduction of wild-type mouse factor VIII cDNA delivered in an E1/E3-deleted adenoviral vector by tail vein injection. All treated mice displayed initial high-level FVIII expression that diminished after 1 month. Ten of 12 mice administered between 6 x 10(9) and 1 x 10(11) particles/mouse along with anti-CD4 antibody showed long-term FVIII activity (0.03-0.05 IU/ml, equivalent to 3-5% of normal FVIII) that corrected the phenotype. Wild-type murine FVIII was a neo-antigen to the KO mice, generating both cytotoxic and humoral immune responses. Immune suppression with anti-CD4 antibody abrogated these immune responses. These data demonstrate that despite the presence of endogenous FVIII protein the immune system still recognizes a species-specific transgene protein as a neo-antigen, eliciting a cytotoxic T cell response. This phenomenon may exist in the treatment of other genetic disorders by gene therapy. PMID:10779165

  7. Correction factors for low perturbation in vivo diodes used in the determination of entrance doses in high energy photon beams

    SciTech Connect

    Roberts, Ralph; Philp, Amanda

    2008-01-15

    Purpose--Low perturbation diodes, with thin buildup caps, can be used to reduce perturbations to the delivered dose. The literature states that additional correction factors are required for low perturbation diodes, however, there are few reported studies into their use. This report measured the dose perturbations and correction factors for diodes with varying buildup cap thicknesses. Methods and materials--Scanditronix EDP15, EDD5, and EDD2 diodes were investigated. Dose perturbations and correction factors for field size, source-surface distance (SSD), obliquity, and wedge were measured in megavoltage photon beams. Results--EDP15 produces a 6% dose perturbation. EDD5 produces a perturbation between 1% and 2%. EDD2 perturbation is negligible. The variation of correction factors for the full buildup EDP15 diode is small and consistent with the literature. The low perturbation diode EDD2 has large correction factors. The field size correction factor varies from 1.38 to 0.87 for 10 MV. The SSD correction factor varies from 0.92 to 1.09 for 10 MV. At the maximum angle measured, the obliquity correction factor is 0.73 for 10 MV. Intermediate results were observed for the EDD5 diode. Conclusions--It is expected that it will be very difficult to achieve accurate in vivo dosimetry using the EDD2 diode. The EDD5 diode may represent a reasonable compromise between EDD2 and the full buildup EDP15. The EDD5 dose perturbation is small and the correction factors are not as large as for EDD2, so accurate in vivo dosimetry may be possible as long as the obliquity is below 45 degrees.

  8. Measured inhomogeneity correction factors for lung in electron beam treatments of the chest wall

    SciTech Connect

    Moldon, C.; El-Khatib, E. )

    1989-01-01

    A set of clinically relevant measurements of percentage depth dose and inhomogeneity correction factors for electron beam irradiation of the chest wall and underlying lung is given. Electron beam nominal energies of 9, 12, 15, and 18 MeV and lung densities of 0.22 g/cm{sup 3} and 0.404 g/cm{sup 3} are considered. This data can serve in treatment planning to indicate the penetration of the beam into the lung and serve as a comparison for calculation algorithms which are used to calculate electron dose absorption in heterogeneous phantoms.

  9. Lengthwise Measurement of Chromatic Dispersion along an Optical Fiber Transmission Link with Enhanced Correction Factor

    NASA Astrophysics Data System (ADS)

    Baig, Mirza Imran; Nahhas, Ahmed M.

    2015-12-01

    In recent years optical time domain reflectometer (OTDR)-based techniques have become a known practice for measuring chromatic dispersion (CD) distribution along an optical fiber transmission link. In this paper, a measurement technique which uses a four-wavelength bidirectional OTDR to evaluate the CD distribution along the length of an optical fiber transmission system has been presented. A novel formulation has been developed for this nondestructive technique to improve the correction factor, which leads to an improvement in the CD and mode field diameter (MFD) measurement. The obtained experimental outcomes are in good agreement with those obtained by the interferometric technique.

  10. Reliability of IGBT in a STATCOM for Harmonic Compensation and Power Factor Correction

    SciTech Connect

    Gopi Reddy, Lakshmi Reddy; Tolbert, Leon M; Ozpineci, Burak; Xu, Yan; Rizy, D Tom

    2012-01-01

    With smart grid integration, there is a need to characterize reliability of a power system by including reliability of power semiconductors in grid related applications. In this paper, the reliability of IGBTs in a STATCOM application is presented for two different applications, power factor correction and harmonic elimination. The STATCOM model is developed in EMTP, and analytical equations for average conduction losses in an IGBT and a diode are derived and compared with experimental data. A commonly used reliability model is used to predict reliability of IGBT.

  11. A Passive Radio-Frequency Identification (RFID) Gas Sensor With Self-Correction Against Fluctuations of Ambient Temperature

    PubMed Central

    Potyrailo, Radislav A.; Surman, Cheryl

    2013-01-01

    Uncontrolled fluctuations of ambient temperature in the field typically greatly reduce accuracy of gas sensors. In this study, we developed an approach for the self-correction against fluctuations of ambient temperature of individual gas and vapor sensors. The main innovation of our work is in the temperature correction which is accomplished without the need for a separate uncoated reference sensor or a separate temperature sensor. Our sensors are resonant inductor-capacitor-resistor (LCR) transducers coated with sensing materials and operated as multivariable passive (battery-free) radio-frequency identification (RFID) sensors. Using our developed approach, we performed quantitation of an exemplary vapor over the temperature range from 25 to 40 C. This technical solution will be attractive in numerous applications where temperature stabilization of a gas sensor or addition of auxiliary temperature or uncoated reference sensors is prohibitive. PMID:23956496

  12. BENDING RADIOGRAPHS AS A PREDICTIVE FACTOR IN SURGICAL CORRECTION OF ADOLESCENT IDIOPATHIC SCOLIOSIS

    PubMed Central

    Gotfryd, Alberto Ofenhejm; Franzin, Fernando José; Poletto, Patrícia Rios; de Laura, Alexandre Spertini; da Silva, Luis Carlos Ferreira

    2015-01-01

    Objective: To evaluate the use of x-rays in dorsal decubitus, as a predictive factor for surgical correction of the main thoracic curve using pedicle screws, on patients with idiopathic adolescent scoliosis. Method: Twenty patients with idiopathic adolescent scoliosis of Lenke types 1A and 1B who were operated using a technique only involving pedicle screws by means of the posterior route were evaluated clinically and radiographically. The curve flexibility was calculated by means of active supine lateral oblique radiographs. The postoperative values for the main thoracic curve were included in a mathematical equation proposed by Cheung et al., with the aim of predicting the expected angular result from the surgical correction. The difference between the expected and actual postoperative results was then investigated regarding its statistical significance. Results: There was statistical significance for all the cases studied, between the values predicted before the operation and the radiographic findings immediately after the operation (p < 0.005). Conclusions: It is possible to predict the percentage surgical correction of the main thoracic curve that will be achieved using pedicle screws in patients with idiopathic adolescent scoliosis of Lenke types 1A and 1B, by means of preoperative supine oblique radiographs.

  13. Factors Associated with Correct and Consistent Insecticide Treated Curtain Use in Iquitos, Peru.

    PubMed

    Paz-Soldan, Valerie A; Bauer, Karin; Morrison, Amy C; Cordova Lopez, Jhonny J; Izumi, Kiyohiko; Scott, Thomas W; Elder, John P; Alexander, Neal; Halsey, Eric S; McCall, Philip J; Lenhart, Audrey

    2016-03-01

    Dengue is an arthropod-borne virus of great public health importance, and control of its mosquito vectors is currently the only available method for prevention. Previous research has suggested that insecticide treated curtains (ITCs) can lower dengue vector infestations in houses. This observational study investigated individual and household-level socio-demographic factors associated with correct and consistent use of ITCs in Iquitos, Peru. A baseline knowledge, attitudes, and practices (KAP) survey was administered to 1,333 study participants, and ITCs were then distributed to 593 households as part of a cluster-randomized trial. Follow up KAP surveys and ITC-monitoring checklists were conducted at 9, 18, and 27 months post-ITC distribution. At 9 months post-distribution, almost 70% of ITCs were hanging properly (e.g. hanging fully extended or tied up), particularly those hung on walls compared to other locations. Proper ITC hanging dropped at 18 months to 45.7%. The odds of hanging ITCs correctly and consistently were significantly greater among those participants who were housewives, knew three or more correct symptoms of dengue and at least one correct treatment for dengue, knew a relative or close friend who had had dengue, had children sleeping under a mosquito net, or perceived a change in the amount of mosquitoes in the home. Additionally, the odds of recommending ITCs in the future were significantly greater among those who perceived a change in the amount of mosquitoes in the home (e.g. perceived the ITCs to be effective). Despite various challenges associated with the sustained effectiveness of the selected ITCs, almost half of the ITCs were still hanging at 18 months, suggesting a feasible vector control strategy for sustained community use. PMID:26967157

  14. Factors Associated with Correct and Consistent Insecticide Treated Curtain Use in Iquitos, Peru

    PubMed Central

    Scott, Thomas W.; Elder, John P.; Alexander, Neal; Halsey, Eric S.; McCall, Philip J.

    2016-01-01

    Dengue is an arthropod-borne virus of great public health importance, and control of its mosquito vectors is currently the only available method for prevention. Previous research has suggested that insecticide treated curtains (ITCs) can lower dengue vector infestations in houses. This observational study investigated individual and household-level socio-demographic factors associated with correct and consistent use of ITCs in Iquitos, Peru. A baseline knowledge, attitudes, and practices (KAP) survey was administered to 1,333 study participants, and ITCs were then distributed to 593 households as part of a cluster-randomized trial. Follow up KAP surveys and ITC-monitoring checklists were conducted at 9, 18, and 27 months post-ITC distribution. At 9 months post-distribution, almost 70% of ITCs were hanging properly (e.g. hanging fully extended or tied up), particularly those hung on walls compared to other locations. Proper ITC hanging dropped at 18 months to 45.7%. The odds of hanging ITCs correctly and consistently were significantly greater among those participants who were housewives, knew three or more correct symptoms of dengue and at least one correct treatment for dengue, knew a relative or close friend who had had dengue, had children sleeping under a mosquito net, or perceived a change in the amount of mosquitoes in the home. Additionally, the odds of recommending ITCs in the future were significantly greater among those who perceived a change in the amount of mosquitoes in the home (e.g. perceived the ITCs to be effective). Despite various challenges associated with the sustained effectiveness of the selected ITCs, almost half of the ITCs were still hanging at 18 months, suggesting a feasible vector control strategy for sustained community use. PMID:26967157

  15. THE CALCULATION OF BURNABLE POISON CORRECTION FACTORS FOR PWR FRESH FUEL ACTIVE COLLAR MEASUREMENTS

    SciTech Connect

    Croft, Stephen; Favalli, Andrea; Swinhoe, Martyn T.

    2012-06-19

    Verification of commercial low enriched uranium light water reactor fuel takes place at the fuel fabrication facility as part of the overall international nuclear safeguards solution to the civilian use of nuclear technology. The fissile mass per unit length is determined nondestructively by active neutron coincidence counting using a neutron collar. A collar comprises four slabs of high density polyethylene that surround the assembly. Three of the slabs contain {sup 3}He filled proportional counters to detect time correlated fission neutrons induced by an AmLi source placed in the fourth slab. Historically, the response of a particular collar design to a particular fuel assembly type has been established by careful cross-calibration to experimental absolute calibrations. Traceability exists to sources and materials held at Los Alamos National Laboratory for over 35 years. This simple yet powerful approach has ensured consistency of application. Since the 1980's there has been a steady improvement in fuel performance. The trend has been to higher burn up. This requires the use of both higher initial enrichment and greater concentrations of burnable poisons. The original analytical relationships to correct for varying fuel composition are consequently being challenged because the experimental basis for them made use of fuels of lower enrichment and lower poison content than is in use today and is envisioned for use in the near term. Thus a reassessment of the correction factors is needed. Experimental reassessment is expensive and time consuming given the great variation between fuel assemblies in circulation. Fortunately current modeling methods enable relative response functions to be calculated with high accuracy. Hence modeling provides a more convenient and cost effective means to derive correction factors which are fit for purpose with confidence. In this work we use the Monte Carlo code MCNPX with neutron coincidence tallies to calculate the influence of Gd{sub 2}O{sub 3} burnable poison on the measurement of fresh pressurized water reactor fuel. To empirically determine the response function over the range of historical and future use we have considered enrichments up to 5 wt% {sup 235}U/{sup tot}U and Gd weight fractions of up to 10 % Gd/UO{sub 2}. Parameterized correction factors are presented.

  16. A new model for the estimation of time of death from vitreous potassium levels corrected for age and temperature.

    PubMed

    Zilg, B; Bernard, S; Alkass, K; Berg, S; Druid, H

    2015-09-01

    Analysis of potassium concentration in the vitreous fluid of the eye is frequently used by forensic pathologists to estimate the postmortem interval (PMI), particularly when other methods commonly used in the early phase of an investigation can no longer be applied. The postmortem rise in vitreous potassium has been recognized for several decades and is readily explained by a diffusion of potassium from surrounding cells into the vitreous fluid. However, there is no consensus regarding the mathematical equation that best describes this increase. The existing models assume a linear increase, but different slopes and starting points have been proposed. In this study, vitreous potassium levels, and a number of factors that may influence these levels, were examined in 462 cases with known postmortem intervals that ranged from 2h to 17 days. We found that the postmortem rise in potassium followed a non-linear curve and that decedent age and ambient temperature influenced the variability by 16% and 5%, respectively. A long duration of agony and a high alcohol level at the time of death contributed less than 1% variability, and evaluation of additional possible factors revealed no detectable impact on the rise of vitreous potassium. Two equations were subsequently generated, one that represents the best fit of the potassium concentrations alone, and a second that represents potassium concentrations with correction for decedent age and/or ambient temperature. The former was associated with narrow confidence intervals in the early postmortem phase, but the intervals gradually increased with longer PMIs. For the latter equation, the confidence intervals were reduced at all PMIs. Therefore, the model that best describes the observed postmortem rise in vitreous potassium levels includes potassium concentration, decedent age, and ambient temperature. Furthermore, the precision of these equations, particularly for long PMIs, is expected to gradually improve by adjusting the constants as more reference data are added over time. A web application that facilitates this calculation process and allows for such future modifications has been developed. PMID:26232848

  17. Beyond the Boltzmann factor for corrections to scaling in ferromagnetic materials and critical fluids

    NASA Astrophysics Data System (ADS)

    Chamberlin, R. V.; Vermaas, J. V.; Wolf, G. H.

    2009-09-01

    The Boltzmann factor comes from the linear change in entropy of an infinite heat bath during a local fluctuation; small systems have significant nonlinear terms. We present theoretical arguments, experimental data, and Monte-Carlo simulations indicating that nonlinear terms may also occur when a particle interacts directly with a finite number of neighboring particles, forming a local region that fluctuates independent of the infinite bath. A possible mechanism comes from the net force necessary to change the state of a particle while conserving local momentum. These finite-sized local regions yield nonlinear fluctuation constraints, beyond the Boltzmann factor. One such fluctuation constraint applied to simulations of the Ising model lowers the energy, makes the entropy extensive, and greatly improves agreement with the corrections to scaling measured in ferromagnetic materials and critical fluids.

  18. Self-energy correction to the hyperfine splitting and the electron g factor in hydrogenlike ions

    SciTech Connect

    Yerokhin, Vladimir A.; Jentschura, Ulrich D.

    2010-01-15

    The hyperfine structure (hfs) and the g factor of a bound electron are caused by external magnetic fields. For the hfs, the magnetic field is due to the nuclear spin. A uniform-in-space and constant-in-time magnetic field is used to probe the bound-electron g factor. The self-energy corrections to these effects are more difficult to evaluate than those to the Lamb shift. Here, we describe a numerical approach for both effects in the notoriously problematic regime of hydrogenlike bound systems with low nuclear charge numbers. The calculation is nonperturbative in the binding Coulomb field. Accurate numerical values for the remainder functions are provided for 2P states and for nS states with n=1,2,3.

  19. QCD corrections to B ? ? form factors from light-cone sum rules

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Ming; Shen, Yue-Long

    2015-09-01

    We compute perturbative corrections to B ? ? form factors from QCD light-cone sum rules with B-meson distribution amplitudes. Applying the method of regions we demonstrate factorization of the vacuum-to-B-meson correlation function defined with an interpolating current for pion, at one-loop level, explicitly in the heavy quark limit. The short-distance functions in the factorization formulae of the correlation function involves both hard and hard-collinear scales; and these functions can be further factorized into hard coefficients by integrating out the hard fluctuations and jet functions encoding the hard-collinear information. Resummation of large logarithms in the short-distance functions is then achieved via the standard renormalization-group approach. We further show that structures of the factorization formulae for fB?+ (q2) and fB?0 (q2) at large hadronic recoil from QCD light-cone sum rules match that derived in QCD factorization. In particular, we perform an exploratory phenomenological analysis of B ? ? form factors, paying attention to various sources of perturbative and systematic uncertainties, and extract |Vub | = (3.05-0.38+0.54|th. 0.09|exp.) 10-3 with the inverse moment of the B-meson distribution amplitude ?B+ (?) determined by reproducing fB?+ (q2 = 0) obtained from the light-cone sum rules with ? distribution amplitudes. Furthermore, we present the invariant-mass distributions of the lepton pair for B ? ???? (? = ?, ?) in the whole kinematic region. Finally, we discuss non-valence Fock state contributions to the B ? ? form factors fB?+ (q2) and fB?0 (q2) in brief.

  20. A correction factor for the impact of cluster randomized sampling and its applications.

    PubMed

    Cousineau, Denis; Laurencelle, Louis

    2016-03-01

    Cluster randomized sampling is 1 method for sampling a population. It requires recruiting subgroups of participants from the population of interest (e.g., whole classes from schools) instead of individuals solicited independently. Here, we demonstrate how clusters affect the standard error of the mean. The presence of clusters influences 2 quantities, the variance of the means and the expected variance. Ignoring clustering produces spurious statistical significance and reduces statistical power when effect sizes are moderate to large. Here, we propose a correction factor. It can be used to estimate standard errors and confidence intervals of the mean under cluster randomized sampling. This correction factor is easy to integrate into regular tests of means and effect sizes. It can also be used to determine sample size needed to reach a prespecified power. Finally, this approach is an easy-to-use alternative to linear mixed modeling and hierarchical linear modeling when there are only 2 levels and no covariates. (PsycINFO Database Record PMID:26651985

  1. Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

    NASA Technical Reports Server (NTRS)

    Blakenship, Clay; Zavodsky, Bradley; Blackwell, William

    2014-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. Forecasts are against ERA reanalyses.

  2. Experimental setup for the determination of the correction factors of the neutron doseratemeters in fast neutron fields

    SciTech Connect

    Iliescu, Elena; Bercea, Sorin; Dudu, Dorin; Celarel, Aurelia

    2013-12-16

    The use of the U-120 Cyclotron of the IFIN-HH allowed to perform a testing bench with fast neutrons in order to determine the correction factors of the doseratemeters dedicated to neutron measurement. This paper deals with researchers performed in order to develop the irradiation facility testing the fast neutrons flux generated at the Cyclotron. This facility is presented, together with the results obtain in determining the correction factor for a doseratemeter dedicated to the neutron dose equivalent rate measurement.

  3. Determination of the thermodynamic correction factor of fluids confined in nano-metric slit pores from molecular simulation

    SciTech Connect

    Collell, Julien; Galliero, Guillaume

    2014-05-21

    The multi-component diffusive mass transport is generally quantified by means of the Maxwell-Stefan diffusion coefficients when using molecular simulations. These coefficients can be related to the Fick diffusion coefficients using the thermodynamic correction factor matrix, which requires to run several simulations to estimate all the elements of the matrix. In a recent work, Schnell et al. [“Thermodynamics of small systems embedded in a reservoir: A detailed analysis of finite size effects,” Mol. Phys. 110, 1069–1079 (2012)] developed an approach to determine the full matrix of thermodynamic factors from a single simulation in bulk. This approach relies on finite size effects of small systems on the density fluctuations. We present here an extension of their work for inhomogeneous Lennard Jones fluids confined in slit pores. We first verified this extension by cross validating the results obtained from this approach with the results obtained from the simulated adsorption isotherms, which allows to determine the thermodynamic factor in porous medium. We then studied the effects of the pore width (from 1 to 15 molecular sizes), of the solid-fluid interaction potential (Lennard Jones 9-3, hard wall potential) and of the reduced fluid density (from 0.1 to 0.7 at a reduced temperature T* = 2) on the thermodynamic factor. The deviation of the thermodynamic factor compared to its equivalent bulk value decreases when increasing the pore width and becomes insignificant for reduced pore width above 15. We also found that the thermodynamic factor is sensitive to the magnitude of the fluid-fluid and solid-fluid interactions, which softens or exacerbates the density fluctuations.

  4. Determination of the thermodynamic correction factor of fluids confined in nano-metric slit pores from molecular simulation

    NASA Astrophysics Data System (ADS)

    Collell, Julien; Galliero, Guillaume

    2014-05-01

    The multi-component diffusive mass transport is generally quantified by means of the Maxwell-Stefan diffusion coefficients when using molecular simulations. These coefficients can be related to the Fick diffusion coefficients using the thermodynamic correction factor matrix, which requires to run several simulations to estimate all the elements of the matrix. In a recent work, Schnell et al. ["Thermodynamics of small systems embedded in a reservoir: A detailed analysis of finite size effects," Mol. Phys. 110, 1069-1079 (2012)] developed an approach to determine the full matrix of thermodynamic factors from a single simulation in bulk. This approach relies on finite size effects of small systems on the density fluctuations. We present here an extension of their work for inhomogeneous Lennard Jones fluids confined in slit pores. We first verified this extension by cross validating the results obtained from this approach with the results obtained from the simulated adsorption isotherms, which allows to determine the thermodynamic factor in porous medium. We then studied the effects of the pore width (from 1 to 15 molecular sizes), of the solid-fluid interaction potential (Lennard Jones 9-3, hard wall potential) and of the reduced fluid density (from 0.1 to 0.7 at a reduced temperature T* = 2) on the thermodynamic factor. The deviation of the thermodynamic factor compared to its equivalent bulk value decreases when increasing the pore width and becomes insignificant for reduced pore width above 15. We also found that the thermodynamic factor is sensitive to the magnitude of the fluid-fluid and solid-fluid interactions, which softens or exacerbates the density fluctuations.

  5. Correction factors for the INER-improved free-air ionization chambers calculated with the Monte Carlo method.

    PubMed

    Lin, Uei-Tyng; Chu, Chien-Hau

    2006-05-01

    Monte Carlo method was used to simulate the correction factors for electron loss and scattered photons for two improved cylindrical free-air ionization chambers (FACs) constructed at the Institute of Nuclear Energy Research (INER, Taiwan). The method is based on weighting correction factors for mono-energetic photons with X-ray spectra. The newly obtained correction factors for the medium-energy free-air chamber were compared with the current values, which were based on a least-squares fit to experimental data published in the NBS Handbook 64 [Wyckoff, H.O., Attix, F.H., 1969. Design of free-air ionization chambers. National Bureau Standards Handbook, No. 64. US Government Printing Office, Washington, DC, pp. 1-16; Chen, W.L., Su, S.H., Su, L.L., Hwang, W.S., 1999. Improved free-air ionization chamber for the measurement of X-rays. Metrologia 36, 19-24]. The comparison results showed the agreement between the Monte Carlo method and experimental data is within 0.22%. In addition, mono-energetic correction factors for the low-energy free-air chamber were calculated. Average correction factors were then derived for measured and theoretical X-ray spectra at 30-50 kVp. Although the measured and calculated spectra differ slightly, the resulting differences in the derived correction factors are less than 0.02%. PMID:16427292

  6. Monte Carlo calculated and experimentally determined output correction factors for small field detectors in Leksell Gamma Knife Perfexion beams.

    PubMed

    Benmakhlouf, H; Johansson, J; Paddick, I; Andreo, P

    2015-05-21

    The measurement of output factors (OF) for the small photon beams generated by Leksell Gamma Knife® (LGK) radiotherapy units is a challenge for the physicist due to the under or over estimation of these factors by a vast majority of the detectors commercially available. Output correction factors, introduced in the international formalism published by Alfonso (2008 Med. Phys. 35 5179-86), standardize the determination of OFs for small photon beams by correcting detector-reading ratios to yield OFs in terms of absorbed-dose ratios. In this work output correction factors for a number of detectors have been determined for LGK Perfexion™ (60)Co γ-ray beams by Monte Carlo (MC) calculations and measurements. The calculations were made with the MC system PENELOPE, scoring the energy deposited in the active volume of the detectors and in a small volume of water; the detectors simulated were two silicon diodes, one liquid ionization chamber (LIC), alanine and TLD. The calculated LIC output correction factors were within ± 0.4%, and this was selected as the reference detector for experimental determinations where output correction factors for twelve detectors were measured, normalizing their readings to those of the LIC. The MC-calculated and measured output correction factors for silicon diodes yielded corrections of up to 5% for the smallest LGK collimator size of 4 mm diameter. The air ionization chamber measurements led to extremely large output correction factors, caused by the well-known effect of partial volume averaging. The corrections were up to 7% for the natural diamond detector in the 4 mm collimator, also due to partial volume averaging, and decreased to within about ± 0.6% for the smaller synthetic diamond detector. The LIC, showing the smallest corrections, was used to investigate machine-to-machine output factor differences by performing measurements in four LGK units with different dose rates. These resulted in OFs within ± 0.6% and ± 0.2% for the 4 mm and 8 mm collimators, respectively, providing evidence for the use of generic OFs for these LGK beams. Using the experimentally derived output correction factors, OFs can be measured using a wide range of commercially available detectors. PMID:25909660

  7. Monte Carlo calculated and experimentally determined output correction factors for small field detectors in Leksell Gamma Knife Perfexion beams

    NASA Astrophysics Data System (ADS)

    Benmakhlouf, H.; Johansson, J.; Paddick, I.; Andreo, P.

    2015-05-01

    The measurement of output factors (OF) for the small photon beams generated by Leksell Gamma Knife® (LGK) radiotherapy units is a challenge for the physicist due to the under or over estimation of these factors by a vast majority of the detectors commercially available. Output correction factors, introduced in the international formalism published by Alfonso (2008 Med. Phys. 35 5179-86), standardize the determination of OFs for small photon beams by correcting detector-reading ratios to yield OFs in terms of absorbed-dose ratios. In this work output correction factors for a number of detectors have been determined for LGK Perfexion™ 60Co γ-ray beams by Monte Carlo (MC) calculations and measurements. The calculations were made with the MC system PENELOPE, scoring the energy deposited in the active volume of the detectors and in a small volume of water; the detectors simulated were two silicon diodes, one liquid ionization chamber (LIC), alanine and TLD. The calculated LIC output correction factors were within ± 0.4%, and this was selected as the reference detector for experimental determinations where output correction factors for twelve detectors were measured, normalizing their readings to those of the LIC. The MC-calculated and measured output correction factors for silicon diodes yielded corrections of up to 5% for the smallest LGK collimator size of 4 mm diameter. The air ionization chamber measurements led to extremely large output correction factors, caused by the well-known effect of partial volume averaging. The corrections were up to 7% for the natural diamond detector in the 4 mm collimator, also due to partial volume averaging, and decreased to within about ± 0.6% for the smaller synthetic diamond detector. The LIC, showing the smallest corrections, was used to investigate machine-to-machine output factor differences by performing measurements in four LGK units with different dose rates. These resulted in OFs within ± 0.6% and ± 0.2% for the 4 mm and 8 mm collimators, respectively, providing evidence for the use of generic OFs for these LGK beams. Using the experimentally derived output correction factors, OFs can be measured using a wide range of commercially available detectors.

  8. A revision factor to the Cutshall self-attenuation correction in (210)Pb gamma-spectrometry measurements.

    PubMed

    Jod?owski, Pawe?

    2016-03-01

    The Cutshall transmission method of determination of self-attenuation correction in (210)Pb measurements by gamma-spectrometry gives the results burdened with errors of up to 10%. The author proposes introducing into the Cutshall correction Cs,Cuts an additional revision factor CCs,Cuts to eliminate errors. The proposed formula of the revision factor describes the CCs,Cuts value depending on the experimentally obtained Cs,Cuts correction. Formula holds true in wide ranges of the measurement geometries and linear attenuation coefficients of both the standard and the sample. PMID:26702546

  9. Coulomb corrections to the extraction of the density and temperature in non-relativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Zheng, Hua; Giuliani, Gianluca; Bonasera, Aldo

    2014-05-01

    We address the role of Coulomb interaction in the determination of densities and temperatures of hot sources produced in heavy ion collisions. Such quantities can be obtained from the quadrupole momentum and multiplicity fluctuations of the emitted light particles. In this paper we modify the method by taking explicitly into account Coulomb corrections. The classical and quantum limits for fermions are discussed. In the classical case we find that the temperatures determined from 3H and 3He, after the Coulomb correction, are very similar to those obtained from neutrons within the constrained molecular dynamics approach. In the quantum case, the proton temperature becomes very similar to neutrons, while densities are not sensitive to the Coulomb corrections.

  10. Factors Affecting Clinical Results after Corrective Osteotomy for Lumbar Degenerative Kyphosis

    PubMed Central

    Kim, Whoan Jeang; Kang, Sung Il; Sung, Hwan Il; Park, Kun Young; Park, Jae Guk; Kwon, Won Cho; Choy, Won Sik

    2010-01-01

    Study Design This study is a prospective, clinical study for lumbar degenerative kyphosis. Purpose To determine the factors affecting postoperative clinical outcomes in patients who undergo corrective osteotomy for lumbar degenerative kyphosis. Overview of Literature Only a small number of studies have reported clinical results for surgery for lumbar degenerative kyphosis. There are almost no studies about prognostic factors that predict postoperative clinical results. Methods This study involved 25 patients who were diagnosed with lumbar degenerative kyphosis and who underwent corrective osteotomy following gait analysis. A pedicle subtraction osteotomy was done at the third lumbar vertebra (L 3). Regarding the fusion level, surgery was done within a range from T10 proximally to S1 distally. Of these, for rigid fixation of a distal part, an iliac screw was used. Pain was evaluated using a 10-point pain scale and a questionnaire about activities. We also evaluated cosmesis and subjective satisfaction using a modified version of the Scoliosis Research Society Outcome-22 (SRS-22) instrument. This assessment was done using a 5-point scale which was designed by us. We assigned patients to group A (good clinical outcomes) if their postoperative pain score was lower than 4 (of 10 points) and if scores indicating activity, cosmesis and subjective satisfaction were higher than 11 (of 15 points). All other patients were assigned to group B (poor clinical outcomes). Results Clinical outcomes were good in 64% of patients (16/25) and poor in 36% (9/25). Regarding cosmesis and subjective satisfaction, there were significant differences between the two groups. There were also significant differences in physical factors of individual patients such as body mass index (BMI): 23.78 2.79 in group A and 26.44 2.75 in group B. On gait analysis, there was a significant difference in the dynamic pelvic tilt: 7.5 3.3 in group A and 11.72 1.89 in group B. Conclusions There is no correlation between preoperative degree of kyphotic deformity and clinical outcomes. The degree of anterior rotation of pelvic tilt does not change significantly; rather, compensatory mechanisms of the pelvis and BMI were found to have more influence. Because neither the degree of satisfaction with clinical outcomes nor the increased activity was relatively higher, a more sincere decision should be made before recommending corrective osteotomy for degenerative lumbar kyphosis. PMID:20622949

  11. A novel correction factor based on extended volume to complement the conformity index

    PubMed Central

    Jin, F; Wang, Y; Wu, Y-Z

    2012-01-01

    Objective We propose a modified conformity index (MCI), based on extended volume, that improves on existing indices by correcting for the insensitivity of previous conformity indices to reference dose shape to assess the quality of high-precision radiation therapy and present an evaluation of its application. Methods In this paper, the MCI is similar to the conformity index suggested by Paddick (CIPaddick), but with a different correction factor. It is shown for three cases: with an extended target volume, with an extended reference dose volume and without an extended volume. Extended volume is generated by expanding the original volume by 0.11.1 cm isotropically. Focusing on the simulation model, measurements of MCI employ a sphere target and three types of reference doses: a sphere, an ellipsoid and a cube. We can constrain the potential advantage of the new index by comparing MCI with CIPaddick. The measurements of MCI in headneck cancers treated with intensity-modulated radiation therapy and volumetric-modulated arc therapy provide a window on its clinical practice. Results The results of MCI for a simulation model and clinical practice are presented and the measurements are corrected for limited spatial resolution. The three types of MCI agree with each other, and comparisons between the MCI and CIPaddick are also provided. Conclusion The results from our analysis show that the proposed MCI can provide more objective and accurate conformity measurement for high-precision radiation therapy. In combination with a dosevolume histogram, it will be a more useful conformity index. PMID:22128127

  12. Evaluation of inhomogeneity correction factors for 6 MV flattening filter-free beams with brass compensators.

    PubMed

    Robinson, Joshua; Opp, Daniel; Zhang, Geoffrey; Feygelman, Vladimir

    2013-01-01

    The 6 MV flattening filter-free (FFF) beam has been commissioned for use with compensators at our institution. This novel combination promises advantages in mitigating tumor motion due to the reduced treatment time made possible by the greatly increased dose rate of the FFF beam. Given the different energy spectrum of the FFF beam and the beam hardening effect of the compensator, the accuracy of the treatment planning system (TPS) model in the presence of low-density heterogeneities cannot be assumed. Therefore, inhomogeneity correction factors (ICF) for an FFF beam attenuated by brass slabs were measured and compared to the TPS calculations in this work. The ICF is the ratio of the point dose in the presence of inhomogeneity to the dose in the same point in a homogeneous medium. The ICFs were measured with an ion chamber at a number of points in a flat water-equivalent slab phantom containing a 7.5 cm deep heterogeneity (air or 0.27 g/cm3 wood). Comparisons for the FFF beam were carried out for the field sizes from 5 5 to 20 20 cm2 with the brass slabs ranging from 0 to 5 cm in thickness. For a low-density wood heterogeneity in a slab phantom, with the exception of the point 1cm beyond the proximal buildup interface, the TPS handles the inhomogeneity correction with the brass-filtered 6 MV FFF beam at the requisite 2% error level. The combinations of field sizes and compensator thicknesses when the error exceeds 2% (2.6% maximum) are not likely to be experienced in clinical practice. In terms of heterogeneity corrections, the beam model is adequate for clinical use. PMID:23652238

  13. Seroprevalence and Risk Factors of Hepatitis C Virus among Juveniles in Correctional Center in Isfahan, Iran

    PubMed Central

    Nokhodian, Zary; Ataei, Behrooz; Kassaian, Nazila; Yaran, Majid; Hassannejad, Razieh; Adibi, Peyman

    2012-01-01

    Objectives: Juveniles in custody are affected by blood borne viruses due to high rates of risk behaviors. Therefore, they have a disproportionate burden of infectious diseases, such as hepatitis C virus (HCV) infection. The purpose of the present study was to determine prevalence and associated characteristics of hepatitis C infection in inmates of a correctional center in Isfahan, Iran. Methods: We conducted a cross-sectional study of HCV infection in 160 youths, who were admitted to correctional center in Isfahan during 2008-2009. Subjects were asked questions regarding behaviors that might put them at high risk for acquiring HCV and blood was drawn for this test. Sera were analyzed for HCV Ab and RIBA test was performed on antibody-positive HCV. We used Chi-square test and logistic regression model to analyze data and P < 0.05 was considered statistically significant. Results: A total of 160 young prisoners (147 boys and 13 girls) were studied. The mean age of the inmates was 16.59 1.24 year. A history of intravenous drug addiction was reported in 3.8% of them. HCV infection was detected in 7 (4.4%) subjects. This study revealed that history of IDU was the main risk factor for HCV (OR, 134.44; 95% confidence interval [CI], 7.29-2481.03). Conclusions: To prevent HCV transmission, proper drug prevention educations should be performed in young age prisoners. PMID:22826752

  14. Shell correction to the ThomasFermi statistical model of plasma with different atomic composition at high and low temperatures

    NASA Astrophysics Data System (ADS)

    Shpatakovskaya, G. V.; Karpov, V. Ya

    2015-11-01

    The refined semiclassical method based on the Thomas-Fermi statistical model takes into account the shell effects by means of an additive correction. The method has been verified in the calculations of a plasma equation of state at high temperatures. To expand its application range to low temperatures some assumptions are revised that have been made to obtain the simple formula for a shell correction. The validity of the assumptions is discussed and the results of their refusal are analyzed. As examples, a number of single-particle states in the ideal plasma of a few elements with strongly differing atomic numbers is calculated.

  15. [Simplified correction factor for the calculation of heart ventricle volume by angiography].

    PubMed

    Malkun, C; María, E; Vargas, A; Hurtado, R; Rangel, A

    1987-01-01

    To measure cardiac volumes from the cineventriculographic silhouette, a calibration factor (fc) is needed to correct the X rays' distorsion and amplification. In the past, several methods have been described in order to obtain this fc, whose determination is often trouble-some, and time consuming, because of the necessity of planimetry, and calibration grid use. In this paper, we describe a method to calculate the fc: after RAO left ventriculography was obtained, a metalic sphere, whose diameter is well known, is filmed at the same incidence and distance of the left ventricle from the X ray tube and image intensifier. A good correlation was found when ventricular volumes estimated by the sphere, plannimetry of a grid, and ellipsoid axes measuring methods were compared (p less than 0.01). Methodology of the three procedures is being discussed and sphere method is recommended, because it avoids the grid use or planimetry performance and because it makes easier the fc determination. PMID:2952086

  16. Design and real time implementation of single phase boost power factor correction converter.

    PubMed

    Bouafassa, Amar; Rahmani, Lazhar; Mekhilef, Saad

    2015-03-01

    This paper presents a real time implementation of the single-phase power factor correction (PFC) AC-DC boost converter. A combination of higher order sliding mode controller based on super twisting algorithm and predictive control techniques are implemented to improve the performance of the boost converter. Due to the chattering effects, the higher order sliding mode control (HOSMC) is designed. Also, the predictive technique is modified taking into account the large computational delays. The robustness of the controller is verified conducting simulation in MATLAB, the results show good performances in both steady and transient states. An experiment is conducted through a test bench based on dSPACE 1104. The experimental results proved that the proposed controller enhanced the performance of the converter under different parameters variations. PMID:25457043

  17. Systematic comparison of beta spectra calculations using improved analytical screening correction with experimental shape factors.

    PubMed

    Mougeot, X

    2016-03-01

    From a review of the available literature, a database of experimental shape factors from measured beta spectra was created in previous work. Classical assumptions applied in beta spectra calculations which avoid the determination of the electron and nuclear wave functions were tested by comparison with each measured spectrum present in the database. From this systematic comparison, it was demonstrated that the typical assumption λk=1 is inappropriate for all forbidden unique transitions. Moreover, the equally common ξ-approximation was also proved to be incorrect for about half of the listed first forbidden non-unique transitions and for all second non-unique ones. In present work, this study has been performed once again using an improved analytical screening correction. General results from previous study still remain the same. Except for allowed transitions, the mean energies in current nuclear databases are expected to be erroneous. Some selected beta spectra are also given to illustrate these results. PMID:26631454

  18. Early Cenozoic benthic foraminiferal isotopes: Species reliability and interspecies correction factors

    NASA Astrophysics Data System (ADS)

    Katz, Miriam E.; Katz, David R.; Wright, James D.; Miller, Kenneth G.; Pak, Dorothy K.; Shackleton, Nicholas J.; Thomas, Ellen

    2003-06-01

    Oxygen and carbon isotope records are important tools used to reconstruct past ocean and climate conditions, with those of benthic foraminifera providing information on the deep oceans. Reconstructions are complicated by interspecies isotopic offsets that result from microhabitat preferences (carbonate precipitation in isotopically distinct environments) and vital effects (species-specific metabolic variation in isotopic fractionation). We provide correction factors for early Cenozoic benthic foraminifera commonly used for isotopic measurements (Cibicidoides spp., Nuttallides truempyi, Oridorsalis spp., Stensioina beccariiformis, Hanzawaia ammophila, and Bulimina spp.), showing that most yield reliable isotopic proxies of environmental change. The statistical methods and larger data sets used in this study provide more robust correction factors than do previous studies. Interspecies isotopic offsets appear to have changed through the Cenozoic, either (1) as a result of evolutionary changes or (2) as an artifact of different statistical methods and data set sizes used to determine the offsets in different studies. Regardless of the reason, the assumption that isotopic offsets have remained constant through the Cenozoic has introduced an 1-2C uncertainty into deep sea paleotemperature calculations. In addition, we compare multiple species isotopic data from a western North Atlantic section that includes the Paleocene-Eocene thermal maximum to determine the most reliable isotopic indicator for this event. We propose that Oridorsalis spp. was the most reliable deepwater isotopic recorder at this location because it was best able to withstand the harsh water conditions that existed at this time; it may be the best recorder at other locations and for other extreme events also.

  19. Error Detection, Factorization and Correction for Multi-View Scene Reconstruction from Aerial Imagery

    SciTech Connect

    Hess-Flores, M

    2011-11-10

    Scene reconstruction from video sequences has become a prominent computer vision research area in recent years, due to its large number of applications in fields such as security, robotics and virtual reality. Despite recent progress in this field, there are still a number of issues that manifest as incomplete, incorrect or computationally-expensive reconstructions. The engine behind achieving reconstruction is the matching of features between images, where common conditions such as occlusions, lighting changes and texture-less regions can all affect matching accuracy. Subsequent processes that rely on matching accuracy, such as camera parameter estimation, structure computation and non-linear parameter optimization, are also vulnerable to additional sources of error, such as degeneracies and mathematical instability. Detection and correction of errors, along with robustness in parameter solvers, are a must in order to achieve a very accurate final scene reconstruction. However, error detection is in general difficult due to the lack of ground-truth information about the given scene, such as the absolute position of scene points or GPS/IMU coordinates for the camera(s) viewing the scene. In this dissertation, methods are presented for the detection, factorization and correction of error sources present in all stages of a scene reconstruction pipeline from video, in the absence of ground-truth knowledge. Two main applications are discussed. The first set of algorithms derive total structural error measurements after an initial scene structure computation and factorize errors into those related to the underlying feature matching process and those related to camera parameter estimation. A brute-force local correction of inaccurate feature matches is presented, as well as an improved conditioning scheme for non-linear parameter optimization which applies weights on input parameters in proportion to estimated camera parameter errors. Another application is in reconstruction pre-processing, where an algorithm detects and discards frames that would lead to inaccurate feature matching, camera pose estimation degeneracies or mathematical instability in structure computation based on a residual error comparison between two different match motion models. The presented algorithms were designed for aerial video but have been proven to work across different scene types and camera motions, and for both real and synthetic scenes.

  20. Replacement correction factors for plane-parallel ion chambers in electron beams

    SciTech Connect

    Wang, Lilie L. W.; Rogers, David W. O.

    2010-02-15

    Purpose: Plane-parallel chambers are recommended by dosimetry protocols for measurements in (especially low-energy) electron beams. In dosimetry protocols, the replacement correction factor P{sub repl} is assumed unity for ''well-guarded'' plane-parallel chambers in electron beams when the front face of the cavity is the effective point of measurement. There is experimental evidence that ion chambers which are not well-guarded (e.g., Markus) have nonunity P{sub repl} values. Monte Carlo simulations are employed in this study to investigate the replacement correction factors for plane-parallel chambers in electron beams. Methods: Using previously established Monte Carlo calculation methods, the values of P{sub repl} are calculated with high statistical precision for the cavities of a variety of plane-parallel chambers in a water phantom irradiated by various electron beams. The dependences of the values of P{sub repl} on the beam quality, phantom depth, as well as the guard ring width are studied. Results: In the dose fall-off region for low-energy beams, the P{sub repl} values are very sensitive to depth. It is found that this is mainly due to the gradient effect, which originates from the fact that the effective point of measurement for many plane-parallel chambers should not be at the front face of the cavity but rather shifted toward the center of the cavity by a fraction of a millimeter. Using the front face of the cavity as the effective point of measurement, the calculated values of P{sub repl} at d{sub ref} are not unity for some well-guarded plane-parallel chambers. The calculated P{sub repl} values for the Roos chamber are close to 1 for all electron beams. The calculation results for the Markus chamber are in good agreement with the measured values. Conclusions: The appropriate selection of the effective point of measurement for plane-parallel chambers in electron beams is an important issue. If the effective point of measurement is correctly accounted for, the P{sub repl} values would be almost independent of depth. Both the guard ring width and the ratio of the collecting volume diameter to the cavity thickness can influence the values of P{sub repl}. For a diameter to thickness ratio of 5 (e.g., NACP02 chamber), the guard width has to be 6 mm for the chamber to be considered as well-guarded, i.e., have a P{sub repl} value of 1.00.

  1. Temperature regulation of virulence factors in the pathogen Vibrio coralliilyticus.

    PubMed

    Kimes, Nikole E; Grim, Christopher J; Johnson, Wesley R; Hasan, Nur A; Tall, Ben D; Kothary, Mahendra H; Kiss, Hajnalka; Munk, A Christine; Tapia, Roxanne; Green, Lance; Detter, Chris; Bruce, David C; Brettin, Thomas S; Colwell, Rita R; Morris, Pamela J

    2012-04-01

    Sea surface temperatures (SST) are rising because of global climate change. As a result, pathogenic Vibrio species that infect humans and marine organisms during warmer summer months are of growing concern. Coral reefs, in particular, are already experiencing unprecedented degradation worldwide due in part to infectious disease outbreaks and bleaching episodes that are exacerbated by increasing SST. For example, Vibrio coralliilyticus, a globally distributed bacterium associated with multiple coral diseases, infects corals at temperatures above 27 C. The mechanisms underlying this temperature-dependent pathogenicity, however, are unknown. In this study, we identify potential virulence mechanisms using whole genome sequencing of V. coralliilyticus ATCC (American Type Culture Collection) BAA-450. Furthermore, we demonstrate direct temperature regulation of numerous virulence factors using proteomic analysis and bioassays. Virulence factors involved in motility, host degradation, secretion, antimicrobial resistance and transcriptional regulation are upregulated at the higher virulent temperature of 27 C, concurrent with phenotypic changes in motility, antibiotic resistance, hemolysis, cytotoxicity and bioluminescence. These results provide evidence that temperature regulates multiple virulence mechanisms in V. coralliilyticus, independent of abundance. The ecological and biological significance of this temperature-dependent virulence response is reinforced by climate change models that predict tropical SST to consistently exceed 27 C during the spring, summer and fall seasons. We propose V. coralliilyticus as a model Gram-negative bacterium to study temperature-dependent pathogenicity in Vibrio-related diseases. PMID:22158392

  2. Calibration of Gyros with Temperature Dependent Scale Factors

    NASA Technical Reports Server (NTRS)

    Belur, Sheela V.; Harman, Richard

    2001-01-01

    The general problem of gyro calibration can be stated as the estimation of the scale factors, misalignments, and drift-rate biases of the gyro using the on-orbit sensor measurements. These gyro parameters have been traditionally treated as temperature-independent in the operational flight dynamics ground systems at NASA Goddard Space Flight Center (GSFC), a scenario which has been successfully applied in the gyro calibration of a large number of missions. A significant departure from this is the Microwave Anisotropy Probe (MAP) mission where, due to the high thermal variations expected during the mission phase, it is necessary to model the scale factors as functions of temperature. This paper addresses the issue of gyro calibration for the MAP gyro model using a manufacturer-supplied model of the variation of scale factors with temperature. The problem is formulated as a least squares problem and solved using the Levenberg-Marquardt algorithm in the MATLAB(R) library function NLSQ. The algorithm was tested on simulated data with Gaussian noise for the quaternions as well as the gyro rates and was found to consistently converge close to the true values. Significant improvement in accuracy was noticed due to the estimation of the temperature-dependent scale factors as against constant scale factors.

  3. Chiral corrections to the scalar form factor in B{sub q}{yields}D{sub q} transitions

    SciTech Connect

    Eeg, Jan O.; Fajfer, Svjetlana; Kamenik, Jernej F.

    2008-10-01

    We consider chiral loop corrections to the scalar form factor in B{sub q}{yields}D{sub q}l{nu} decays. First we consider chiral corrections to the 1/m{sub Q} suppressed operators and then we propose a procedure for the extraction of the relevant form factor using lattice QCD results. In particular, the extraction of a B*{yields}D* matrix element on the lattice can be used to determine all the necessary 1/m{sub Q} suppressed contributions to the scalar form factor in B{yields}D transitions. In the case of (B{sub s}{yields}D{sub s})/(B{yields}D) decay rate ratios we speculate that effects of kinematics and chiral corrections tend to cancel for the scalar form factor contributions. In particular the 1/m{sub Q} suppression of chiral corrections is compensated by the potentially large SU(3) flavor symmetry breaking corrections. The calculated corrections are relevant for the precise determination of possible new physics effects in B{sub q}{yields}D{sub q}l{nu} decays.

  4. Region of validity of the finitetemperature ThomasFermi model with respect to quantum and exchange corrections

    SciTech Connect

    Dyachkov, Sergey; Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow Region 141700 ; Levashov, Pavel; Tomsk State University, 36 Lenin Prospekt, Tomsk 634050

    2014-05-15

    We determine the region of applicability of the finitetemperature ThomasFermi model and its thermal part with respect to quantum and exchange corrections. Very high accuracy of computations has been achieved by using a special approach for the solution of the boundary problem and numerical integration. We show that the thermal part of the model can be applied at lower temperatures than the full model. Also we offer simple approximations of the boundaries of validity for practical applications.

  5. A Power Factor Corrected SMPS with Improved Power Quality for Welding Applications

    NASA Astrophysics Data System (ADS)

    Narula, Swati; Singh, Bhim; Bhuvaneswari, G.; Pandey, Rahul

    2015-04-01

    This paper presents the analysis, design and implementation of a power factor corrected Arc Welding Power Supply (AWPS) with a boost converter at the front end and three full-bridge (FB) converters connected in parallel at the load end. The modular arrangement of the FB converters offers several meritorious features like usage of power devices with comparatively lower voltage and current ratings, ease of power expandability, easy maintenance, etc. The boost converter operates in continuous conduction mode minimizing the input current ripple and leading to the lowest RMS current thereby improving the input power quality. Individual control loops are designed for each power stage. A dual loop control scheme is employed to incorporate over-current limit on the proposed AWPS which ensures excellent weld bead quality. The proposed AWPS is implemented to validate its performance over a wide range of line/load variations. Test results confirm its fast parametrical response to load and source voltage variations and over-current protection leading to improved welding performance and weld bead quality. The system is found to perform extremely well with very low input current THD and unity power factor, adhering to international power quality norms.

  6. Correction of xeroderma pigmentosum repair defect by basal transcription factor BTF2 (TFIIH).

    PubMed Central

    van Vuuren, A J; Vermeulen, W; Ma, L; Weeda, G; Appeldoorn, E; Jaspers, N G; van der Eb, A J; Bootsma, D; Hoeijmakers, J H; Humbert, S

    1994-01-01

    ERCC3 was initially identified as a gene correcting the nucleotide excision repair (NER) defect of xeroderma pigmentosum complementation group B (XP-B). The recent finding that its gene product is identical to the p89 subunit of basal transcription factor BTF2(TFIIH), opened the possibility that it is not directly involved in NER but that it regulates the transcription of one or more NER genes. Using an in vivo microinjection repair assay and an in vitro NER system based on cell-free extracts we demonstrate that ERCC3 in BTF2 is directly implicated in excision repair. Antibody depletion experiments support the idea that the p62 BTF2 subunit and perhaps the entire transcription factor function in NER. Microinjection experiments suggest that exogenous ERCC3 can exchange with ERCC3 subunits in the complex. Expression of a dominant negative K436-->R ERCC3 mutant, expected to have lost all helicase activity, completely abrogates NER and transcription and concomitantly induces a dramatic chromatin collapse. These findings establish the role of ERCC3 and probably the entire BTF2 complex in transcription in vivo which was hitherto only demonstrated in vitro. The results strongly suggest that transcription itself is a critical component for maintenance of chromatin structure. The remarkable dual role of ERCC3 in NER and transcription provides a clue in understanding the complex clinical features of some inherited repair syndromes. Images PMID:8157004

  7. Phenotypic correction of hemophilia A by ectopic expression of activated factor VII in platelets.

    PubMed

    Ohmori, Tsukasa; Ishiwata, Akira; Kashiwakura, Yuji; Madoiwa, Seiji; Mitomo, Katsuyuki; Suzuki, Hidenori; Hasegawa, Mamoru; Mimuro, Jun; Sakata, Yoichi

    2008-08-01

    Platelets are receiving much attention as novel target cells to secrete a coagulation factor for hemophilia gene therapy. In order to extend the application of platelet-directed gene therapy, we examined whether ectopic expression of activated factor VII (FVIIa) in platelets would result in an efficient bypass therapy to induce sufficient thrombin generation on platelet surfaces in mice with hemophilia A. Transduction of bone marrow cells with a simian immunodeficiency virus (SIV)-based lentiviral vector harboring the platelet-specific GPIb alpha promoter resulted in efficient transgene expression in platelets. FVIIa antigen was expressed in platelets by this SIV system; FVII transgene products were found to localize in the cytoplasm and translocate toward the sub-membrane zone and cell surface after activation. Although FVII antigen levels in platelets did not reach the therapeutic levels seen with FVIIa infusion therapy, whole-blood coagulation, as assessed by thromboelastography, was significantly improved in mice with hemophilia A. Further, we observed correction of the bleeding phenotype in mice with hemophilia A after transplantation, even in the presence of FVIII-neutralizing antibodies. Our results demonstrate that FVIIa-expressing platelets can strengthen hemostatic function and may be useful in treating hemophilia and other inherited bleeding disorders. These findings are comparable to the proven therapeutic effects of FVIIa infusion. PMID:18523449

  8. Output correction factors for nine small field detectors in 6 MV radiation therapy photon beams: A PENELOPE Monte Carlo study

    SciTech Connect

    Benmakhlouf, Hamza; Sempau, Josep; Andreo, Pedro

    2014-04-15

    Purpose: To determine detector-specific output correction factors,k{sub Q} {sub c{sub l{sub i{sub n}}}} {sub ,Q} {sub m{sub s{sub r}}} {sup f{sub {sup {sub c}{sub l}{sub i}{sub n}{sub {sup ,f{sub {sup {sub m}{sub s}{sub r}{sub ,}}}}}}}} in 6 MV small photon beams for air and liquid ionization chambers, silicon diodes, and diamond detectors from two manufacturers. Methods: Field output factors, defined according to the international formalism published byAlfonso et al. [Med. Phys. 35, 5179–5186 (2008)], relate the dosimetry of small photon beams to that of the machine-specific reference field; they include a correction to measured ratios of detector readings, conventionally used as output factors in broad beams. Output correction factors were calculated with the PENELOPE Monte Carlo (MC) system with a statistical uncertainty (type-A) of 0.15% or lower. The geometries of the detectors were coded using blueprints provided by the manufacturers, and phase-space files for field sizes between 0.5 × 0.5 cm{sup 2} and 10 × 10 cm{sup 2} from a Varian Clinac iX 6 MV linac used as sources. The output correction factors were determined scoring the absorbed dose within a detector and to a small water volume in the absence of the detector, both at a depth of 10 cm, for each small field and for the reference beam of 10 × 10 cm{sup 2}. Results: The Monte Carlo calculated output correction factors for the liquid ionization chamber and the diamond detector were within about ±1% of unity even for the smallest field sizes. Corrections were found to be significant for small air ionization chambers due to their cavity dimensions, as expected. The correction factors for silicon diodes varied with the detector type (shielded or unshielded), confirming the findings by other authors; different corrections for the detectors from the two manufacturers were obtained. The differences in the calculated factors for the various detectors were analyzed thoroughly and whenever possible the results were compared to published data, often calculated for different accelerators and using the EGSnrc MC system. The differences were used to estimate a type-B uncertainty for the correction factors. Together with the type-A uncertainty from the Monte Carlo calculations, an estimation of the combined standard uncertainty was made, assigned to the mean correction factors from various estimates. Conclusions: The present work provides a consistent and specific set of data for the output correction factors of a broad set of detectors in a Varian Clinac iX 6 MV accelerator and contributes to improving the understanding of the physics of small photon beams. The correction factors cannot in general be neglected for any detector and, as expected, their magnitude increases with decreasing field size. Due to the reduced number of clinical accelerator types currently available, it is suggested that detector output correction factors be given specifically for linac models and field sizes, rather than for a beam quality specifier that necessarily varies with the accelerator type and field size due to the different electron spot dimensions and photon collimation systems used by each accelerator model.

  9. Intraosseous delivery of lentiviral vectors targeting factor VIII expression in platelets corrects murine hemophilia A.

    PubMed

    Wang, Xuefeng; Shin, Simon C; Chiang, Andy F J; Khan, Iram; Pan, Dao; Rawlings, David J; Miao, Carol H

    2015-04-01

    Intraosseous (IO) infusion of lentiviral vectors (LVs) for in situ gene transfer into bone marrow may avoid specific challenges posed by ex vivo gene delivery, including, in particular, the requirement of preconditioning. We utilized IO delivery of LVs encoding a GFP or factor VIII (FVIII) transgene directed by ubiquitous promoters (a MND or EF-1?-short element; M-GFP-LV, E-F8-LV) or a platelet-specific, glycoprotein-1b? promoter (G-GFP-LV, G-F8-LV). A single IO infusion of M-GFP-LV or G-GFP-LV achieved long-term and efficient GFP expression in Lineage(-)Sca1(+)c-Kit(+) hematopoietic stem cells and platelets, respectively. While E-F8-LV produced initially high-level FVIII expression, robust anti-FVIII immune responses eliminated functional FVIII in circulation. In contrast, IO delivery of G-F8-LV achieved long-term platelet-specific expression of FVIII, resulting in partial correction of hemophilia A. Furthermore, similar clinical benefit with G-F8-LV was achieved in animals with pre-existing anti-FVIII inhibitors. These findings further support platelets as an ideal FVIII delivery vehicle, as FVIII, stored in ?-granules, is protected from neutralizing antibodies and, during bleeding, activated platelets locally excrete FVIII to promote clot formation. Overall, a single IO infusion of G-F8-LV was sufficient to correct hemophilia phenotype for long term, indicating that this approach may provide an effective means to permanently treat FVIII deficiency. PMID:25655313

  10. INTRINSIC COLORS, TEMPERATURES, AND BOLOMETRIC CORRECTIONS OF PRE-MAIN-SEQUENCE STARS

    SciTech Connect

    Pecaut, Mark J.; Mamajek, Eric E.

    2013-09-01

    We present an analysis of the intrinsic colors and temperatures of 5-30 Myr old pre-main-sequence (pre-MS) stars using the F0- through M9-type members of nearby, negligibly reddened groups: the η Cha cluster, the TW Hydra Association, the β Pic Moving Group, and the Tucana-Horologium Association. To check the consistency of spectral types from the literature, we estimate new spectral types for 52 nearby pre-MS stars with spectral types F3 through M4 using optical spectra taken with the SMARTS 1.5 m telescope. Combining these new types with published spectral types and photometry from the literature (Johnson-Cousins BVI{sub C} , 2MASS JHK{sub S} and WISE W1, W2, W3, and W4), we derive a new empirical spectral type-color sequence for 5-30 Myr old pre-MS stars. Colors for pre-MS stars match dwarf colors for some spectral types and colors, but for other spectral types and colors, deviations can exceed 0.3 mag. We estimate effective temperatures (T {sub eff}) and bolometric corrections (BCs) for our pre-MS star sample through comparing their photometry to synthetic photometry generated using the BT-Settl grid of model atmosphere spectra. We derive a new T {sub eff} and BC scale for pre-MS stars, which should be a more appropriate match for T Tauri stars than often-adopted dwarf star scales. While our new T {sub eff} scale for pre-MS stars is within ≅100 K of dwarfs at a given spectral type for stars

  11. The effect of temperature on attenuation-correction schemes in rain using polarization propagation differential phase shift

    NASA Technical Reports Server (NTRS)

    Jameson, A. R.

    1992-01-01

    The study elucidates and quantifies differences in the response of the rate of change of polarization propagation differential phase shift Phi, the rate of attenuation for a horizontally/vertically polarized wave A(H,V), and the rate of polarization differential attenuation A(H-V) to temperature. It is shown that if the effects of temperature when estimating A(H) and A(H-V) from Phi are neglected, the average fractional standard error increases only slightly at 9 GHz but significantly at 5 and 3 GHz. Errors at 5 and 3 GHz are about two to three times those at 9 GHz. The performance of Phi-based schemes of attenuation correction at these lower frequencies is much more significantly degraded by temperature uncertainty than at 9 GHz. It is concluded that it is best to use Phi to correct for attenuation at the least-attenuating frequencies.

  12. Real-time prediction of seismic ground motion (II): real-time correction of frequency-dependent site amplification factors

    NASA Astrophysics Data System (ADS)

    Hoshiba, M.

    2013-05-01

    In Part I, real-time estimation of wavefield using data assimilation and time evolutional prediction using Kirchhoff integral are discussed. For actual application of them in Earthquake Early Warning (EEW), site amplification factor should be corrected in real time. Site amplification is an important factor in addition to source and propagation factors which control the amplitude of seismic waves. The site factor has frequency dependence, and the amplification of high frequency waves is usually different from that of low frequency waves. In many EEW systems, the site amplification factor has been considered as scalar value ignoring the frequency dependence, in which amplification of PGA (or PGV) or increment of seismic intensity is used. The frequency-dependent site amplification factor has not yet fully taken into account. Data assimilation and Kirchhoff integral are powerful techniques for time evolutional prediction. For the application in EEW, frequency-dependent site amplification factors should be corrected in real time (inverse filtering) at observation points, and then should be applied in real time (simulation filtering) for evaluation of ground motion at a target point. A method is proposed in which the frequency dependent site factor can be corrected in real time. The frequency-dependent site factor is modeled by the linear system of the first and second order low-pass and high-pass filters. A causal recursive IIR filter in time domain is estimated from the linear system using bilinear transform and pre-warping methods of digital filtering technique. Using the causal filter, the site amplification factor is corrected in real time even when the site factor has strong frequency dependence. The causal filter enables us to predict the waveforms at target point when the seismic wave start to be observed at the observation point, if the site amplification factor of the target point relative to that of the observation point is known. Instead of rapid estimation of hypocentral location and magnitude, time evolutional prediction is a powerful method for real-time prediction of ground motion for EEW, which is applicable even for cases of strong rupture directivity and large source extent. Techniques of data assimilation and real time correction of site amplification factors will be applied for the time evolutional prediction. An example of the real time correction of the frequency-dependent site factors is presented using data from borehole seismometer (depth: 504m), and also using data of neighboring stations (distance: 28km) in the Kanto region, Japan. Waveforms of the target point are reproduced well from the waveform at the observation point by using the approach of the time evolutional prediction.

  13. Determination of ?Pu airborne concentration alpha correction factor for a zinc sulfide detector via ambient Rn progeny air sampling.

    PubMed

    Hale, Alan C; Tries, Mark A

    2011-02-01

    This research empirically determined the ?Pu airborne concentration alpha correction factor for an ADM-300 zinc sulfide detection system via ambient Rn progeny air sampling using a RADeCO high volume air sampler. Radon progeny air samples were collected on a four inch glass fiber filter and evaluated on both a high purity germanium detector and the ADM?-300 simultaneously using the three count method. These data were analyzed to obtain a loss fraction in the glass fiber filter for the ?Bi collected. The ?Bi response then was used to estimate a loss fraction for ?Pu. The ?Pu airborne concentration alpha correction factor for the ADM-300 detection system was found to be 445 47 dpm ft cpm? m? as compared to a previously published correction factor of 500 dpm ft cpm? m?. PMID:21399436

  14. Method for the rapid temperature correction of a transmission in an inhomogeneous atmosphere

    NASA Technical Reports Server (NTRS)

    Varnava, V. A.; Karasev, A. B.; Sapunov, V. V.; Fedichev, O. B.

    1979-01-01

    The value of the transmission function in a heterogeneous atmosphere is determined by iterative correction of values in particular layers. The iterative equation and a set of absolute values of errors is presented in two tables.

  15. Detector to detector corrections: A comprehensive experimental study of detector specific correction factors for beam output measurements for small radiotherapy beams

    SciTech Connect

    Azangwe, Godfrey Grochowska, Paulina; Izewska, Joanna; Meghzifene, Ahmed; Georg, Dietmar; Hopfgartner, Johannes; Lechner, Wolfgang; Mizuno, Hideyuki; Fukumura, Akifumi; Yajima, Kaori; Gouldstone, Clare; Sharpe, Peter; Palmans, Hugo

    2014-07-15

    Purpose: The aim of the present study is to provide a comprehensive set of detector specific correction factors for beam output measurements for small beams, for a wide range of real time and passive detectors. The detector specific correction factors determined in this study may be potentially useful as a reference data set for small beam dosimetry measurements. Methods: Dose response of passive and real time detectors was investigated for small field sizes shaped with a micromultileaf collimator ranging from 0.6 × 0.6 cm{sup 2} to 4.2 × 4.2 cm{sup 2} and the measurements were extended to larger fields of up to 10 × 10 cm{sup 2}. Measurements were performed at 5 cm depth, in a 6 MV photon beam. Detectors used included alanine, thermoluminescent dosimeters (TLDs), stereotactic diode, electron diode, photon diode, radiophotoluminescent dosimeters (RPLDs), radioluminescence detector based on carbon-doped aluminium oxide (Al{sub 2}O{sub 3}:C), organic plastic scintillators, diamond detectors, liquid filled ion chamber, and a range of small volume air filled ionization chambers (volumes ranging from 0.002 cm{sup 3} to 0.3 cm{sup 3}). All detector measurements were corrected for volume averaging effect and compared with dose ratios determined from alanine to derive a detector correction factors that account for beam perturbation related to nonwater equivalence of the detector materials. Results: For the detectors used in this study, volume averaging corrections ranged from unity for the smallest detectors such as the diodes, 1.148 for the 0.14 cm{sup 3} air filled ionization chamber and were as high as 1.924 for the 0.3 cm{sup 3} ionization chamber. After applying volume averaging corrections, the detector readings were consistent among themselves and with alanine measurements for several small detectors but they differed for larger detectors, in particular for some small ionization chambers with volumes larger than 0.1 cm{sup 3}. Conclusions: The results demonstrate how important it is for the appropriate corrections to be applied to give consistent and accurate measurements for a range of detectors in small beam geometry. The results further demonstrate that depending on the choice of detectors, there is a potential for large errors when effects such as volume averaging, perturbation and differences in material properties of detectors are not taken into account. As the commissioning of small fields for clinical treatment has to rely on accurate dose measurements, the authors recommend the use of detectors that require relatively little correction, such as unshielded diodes, diamond detectors or microchambers, and solid state detectors such as alanine, TLD, Al{sub 2}O{sub 3}:C, or scintillators.

  16. CORRIGENDUM: Diaphragm correction factors for free-air chamber standards for air kerma in x-rays Diaphragm correction factors for free-air chamber standards for air kerma in x-rays

    NASA Astrophysics Data System (ADS)

    Burns, D. T.; Kessler, C.

    2009-07-01

    The paper describes the Monte Carlo calculation of diaphragm correction factors for free-air ionization chamber standards. Although not submitted for publication until December 2008, this work was carried out in 2006 and preliminary results were presented at the World Congress on Medical Physics and Biomedical Engineering of that year (Kessler 2006). Subsequently, Mainegra-Hing et al (2008) published the results of similar calculations for their own standard. In retrospect, the authors regret that they did not take the opportunity to revise their manuscript to include a citation to the work of Mainegra-Hing et al. The following sentence should be added at the end of the second paragraph of section 7 (Discussion) on page 2744 (following the text '...correction for diaphragm scatter.'): 'In a more recent work, Mainegra-Hing et al (2008) calculated a combined correction for diaphragm transmission and scatter of 0.9984 for their 250 kV measurement conditions. This is in agreement with the value 0.9983(3) obtained in the present work.' References Kessler C 2006 Calculation of the aperture scatter and transmission correction factors for the BIPM free-air chamber standards using the code PENELOPE World Congress on Medical Physics and Biomedical Engineering (27 August-1 September 2006, Seoul, Korea) Mainegra-Hing E, Reynaert N and Kawrakow I 2008 Novel approach for the Monte Carlo calculation of free-air chamber correction factors Med. Phys. 35 3650-60

  17. Temperature can interact with landscape factors to affect songbird productivity.

    PubMed

    Cox, W Andrew; Thompson, Frank R; Reidy, Jennifer L; Faaborg, John

    2013-04-01

    Increased temperatures and more extreme weather patterns associated with global climate change can interact with other factors that regulate animal populations, but many climate change studies do not incorporate other threats to wildlife in their analyses. We used 20 years of nest-monitoring data from study sites across a gradient of habitat fragmentation in Missouri, USA, to investigate the relative influence of weather variables (temperature and precipitation) and landscape factors (forest cover and edge density) on the number of young produced per nest attempt (i.e., productivity) for three species of songbirds. We detected a strong forest cover × temperature interaction for the Acadian Flycatcher (Empidonax virescens) on productivity. Greater forest cover resulted in greater productivity because of reduced brood parasitism and increased nest survival, whereas greater temperatures reduced productivity in highly forested landscapes because of increased nest predation but had no effect in less forested landscapes. The Indigo Bunting (Passerina cyanea) exhibited a similar pattern, albeit with a marginal forest cover × temperature interaction. By contrast, productivity of the Northern Cardinal (Cardinalis cardinalis) was not influenced by landscape effects or temperature. Our results highlight a potential difficulty of managing wildlife in response to global change such as habitat fragmentation and climate warming, as the habitat associated with the greatest productivity for flycatchers was also that most negatively influenced by high temperatures. The influence of high temperatures on nest predation (and therefore, nest predators) underscores the need to acknowledge the potential complexity of species' responses to climate change by incorporating a more thorough consideration of community ecology in the development of models of climate impacts on wildlife. PMID:23504884

  18. Correction analysis for a supersonic water cooled total temperature probe tested to 1370 K

    NASA Technical Reports Server (NTRS)

    Lagen, Nicholas T.; Seiner, John M.

    1991-01-01

    The authors address the thermal analysis of a water cooled supersonic total temperature probe tested in a Mach 2 flow, up to 1366 K total temperature. The goal of this experiment was the determination of high-temperature supersonic jet mean flow temperatures. An 8.99 cm exit diameter water cooled nozzle was used in the tests. It was designed for exit Mach 2 at 1366 K exit total temperature. Data along the jet centerline were obtained for total temperatures of 755 K, 1089 K, and 1366 K. The data from the total temperature probe were affected by the water coolant. The probe was tested through a range of temperatures between 755 K and 1366 K with and without the cooling system turned on. The results were used to develop a relationship between the indicated thermocouple bead temperature and the freestream total temperature. The analysis and calculated temperatures are presented.

  19. Sulphur abundance determinations in star-forming regions - I. Ionization correction factor

    NASA Astrophysics Data System (ADS)

    Dors, O. L.; Pérez-Montero, E.; Hägele, G. F.; Cardaci, M. V.; Krabbe, A. C.

    2016-03-01

    In this work, we used a grid of photoionization models combined with stellar population synthesis models to derive reliable ionization correction factors (ICFs) for the sulphur in star-forming regions. These models cover a large range of nebular parameters and yielding ionic abundances in consonance with those derived through optical and infrared observational data of star-forming regions. From our theoretical ICFs, we suggested an α value of 3.27 ± 0.01 in the classical Stasińska formulae. We compared the total sulphur abundance in the gas phase of a large sample of objects by using our theoretical ICF and other approaches. In average, the differences between the determinations via the use of the different ICFs considered are similar to the uncertainties in the S/H estimations. Nevertheless, we noted that for some objects it could reach up to about 0.3 dex for the low-metallicity regime. Despite of the large scatter of the points, we found a trend of S/O ratio to decrease with the metallicity, independently of the ICF used to compute the sulphur total abundance.

  20. Control of Dual-Opposed Stirling Convertors with Active Power Factor Correction Controllers

    NASA Technical Reports Server (NTRS)

    Regan, Timothy F.; Lewandowski, Edward J.; Schreiber, Jeffrey G.

    2007-01-01

    When using recently-developed active power factor correction (APFC) controllers in power systems comprised of dual-opposed free-piston Stirling convertors, a variety of configurations of the convertors and controller(s) can be considered, with configuration ultimately selected based on benefits of efficiency, reliability, and robust operation. The configuration must not only achieve stable control of the two convertors, but also synchronize and regulate motion of the pistons to minimize net dynamic forces. The NASA Glenn Research Center (GRC) System Dynamic Model (SDM) was used to study ten configurations of dual-opposed convertor systems. These configurations considered one controller with the alternators connected in series or in parallel, and two controllers with the alternators not connected (isolated). For the configurations where the alternators were not connected, several different approaches were evaluated to synchronize the two convertors. In addition, two thermodynamic configurations were considered: two convertors with isolated working spaces and convertors with a shared expansion space. Of the ten configurations studied, stable operating modes were found for four. Three of those four had a common expansion space. One stable configuration was found for the dual-opposed convertors with separate working spaces. That configuration required isochronous control of both convertors, and two APFC controllers were used to accomplish this. A frequency/phase control loop was necessary to allow each APFC controller to synchronize its associated convertor with a common frequency.

  1. Continuous correction of differential path length factor in near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Talukdar, Tanveer; Moore, Jason H.; Diamond, Solomon G.

    2013-05-01

    In continuous-wave near-infrared spectroscopy (CW-NIRS), changes in the concentration of oxyhemoglobin and deoxyhemoglobin can be calculated by solving a set of linear equations from the modified Beer-Lambert Law. Cross-talk error in the calculated hemodynamics can arise from inaccurate knowledge of the wavelength-dependent differential path length factor (DPF). We apply the extended Kalman filter (EKF) with a dynamical systems model to calculate relative concentration changes in oxy- and deoxyhemoglobin while simultaneously estimating relative changes in DPF. Results from simulated and experimental CW-NIRS data are compared with results from a weighted least squares (WLSQ) method. The EKF method was found to effectively correct for artificially introduced errors in DPF and to reduce the cross-talk error in simulation. With experimental CW-NIRS data, the hemodynamic estimates from EKF differ significantly from the WLSQ (p<0.001). The cross-correlations among residuals at different wavelengths were found to be significantly reduced by the EKF method compared to WLSQ in three physiologically relevant spectral bands 0.04 to 0.15 Hz, 0.15 to 0.4 Hz and 0.4 to 2.0 Hz (p<0.001). This observed reduction in residual cross-correlation is consistent with reduced cross-talk error in the hemodynamic estimates from the proposed EKF method.

  2. Continuous correction of differential path length factor in near-infrared spectroscopy.

    PubMed

    Talukdar, Tanveer; Moore, Jason H; Diamond, Solomon G

    2013-05-01

    In continuous-wave near-infrared spectroscopy (CW-NIRS), changes in the concentration of oxyhemoglobin and deoxyhemoglobin can be calculated by solving a set of linear equations from the modified Beer-Lambert Law. Cross-talk error in the calculated hemodynamics can arise from inaccurate knowledge of the wavelength-dependent differential path length factor (DPF). We apply the extended Kalman filter (EKF) with a dynamical systems model to calculate relative concentration changes in oxy- and deoxyhemoglobin while simultaneously estimating relative changes in DPF. Results from simulated and experimental CW-NIRS data are compared with results from a weighted least squares (WLSQ) method. The EKF method was found to effectively correct for artificially introduced errors in DPF and to reduce the cross-talk error in simulation. With experimental CW-NIRS data, the hemodynamic estimates from EKF differ significantly from the WLSQ (p < 0.001). The cross-correlations among residuals at different wavelengths were found to be significantly reduced by the EKF method compared to WLSQ in three physiologically relevant spectral bands 0.04 to 0.15 Hz, 0.15 to 0.4 Hz and 0.4 to 2.0 Hz (p < 0.001). This observed reduction in residual cross-correlation is consistent with reduced cross-talk error in the hemodynamic estimates from the proposed EKF method. PMID:23640027

  3. Control of Dual-Opposed Stirling Convertors with Active Power Factor Correction Controllers

    NASA Technical Reports Server (NTRS)

    Regan, Timothy F.; Lewandowski, Edward J.; Schreiber, Jeffrey G.

    2006-01-01

    When using recently-developed active power factor correction (APFC) controllers in power systems comprised of dual-opposed free-piston Stirling convertors, a variety of configurations of the convertors and controller(s) can be considered, with configuration ultimately selected based on benefits of efficiency, reliability, and robust operation. The configuration must not only achieve stable control of the two convertors, but also synchronize and regulate motion of the pistons to minimize net dynamic forces. The NASA Glenn Research Center (GRC) System Dynamic Model (SDM) was used to study ten configurations of dual-opposed convertor systems. These configurations considered one controller with the alternators connected in series or in parallel, and two controllers with the alternators not connected (isolated). For the configurations where the alternators were not connected, several different approaches were evaluated to synchronize the two convertors. In addition, two thermodynamic configurations were considered: two convertors with isolated working spaces and convertors with a shared expansion space. Of the ten configurations studied, stable operating modes were found for four. Three of those four had a common expansion space. One stable configuration was found for the dual-opposed convertors with separate working spaces. That configuration required isochronous control of both convertors, and two APFC controllers were used to accomplish this. A frequency/phase control loop was necessary to allow each APFC controller to synchronize its associated convertor with a common frequency.

  4. Investigation of systematic uncertainties in Monte Carlo-calculated beam quality correction factors.

    PubMed

    Wulff, J; Heverhagen, J T; Zink, K; Kawrakow, I

    2010-08-21

    Modern Monte Carlo codes allow for the calculation of ion chamber specific beam quality correction factors k(Q), which are needed for dosimetry in radiotherapy. While statistical (type A) uncertainties of the calculated data can be minimized sufficiently, the influence of systematic (type B) uncertainties is mostly unknown. This study presents an investigation of systematic uncertainties of Monte Carlo-based k(Q) values for a NE2571 thimble ion chamber, calculated with the EGSnrc system. Starting with some general investigation on transport parameter settings, the influence of geometry and source variations is studied. Furthermore, a systematic examination of uncertainties due to cross section is introduced by determining the sensitivity of k(Q) results to changes in cross section data. For this purpose, single components of the photon cross sections and the mean excitation energy I in the electron stopping powers are varied. The corresponding sensitivities are subsequently applied with information of standard uncertainties for the cross section data found in the literature. It turns out that the calculation of k(Q) factors with EGSnrc is mostly insensitive to transport settings within the statistical uncertainties of approximately 0.1%. Severe changes in the dimensions of the chamber lead to comparatively small, insignificant changes. Further, the inclusion of realistic beam models, delivering a complete phase space instead of simple photon spectra, does not significantly influence the result. However, the uncertainties in electron cross sections have an impact on the final uncertainty of k(Q) to a comparatively large degree. For the NE2571 chamber investigated in this work, this uncertainty amounts to 0.4% at 24 MV, decreasing to 0.2% at 6 MV. PMID:20668340

  5. Myopia Stabilization and Associated Factors Among Participants in the Correction of Myopia Evaluation Trial (COMET)

    PubMed Central

    2013-01-01

    Purpose. To use the Gompertz function to estimate the age and the amount of myopia at stabilization and to evaluate associated factors in the Correction of Myopia Evaluation Trial (COMET) cohort, a large ethnically diverse group of myopic children. Methods. The COMET enrolled 469 ethnically diverse children aged 6 to younger than 12 years with spherical equivalent refraction between ?1.25 and ?4.50 diopters (D). Noncycloplegic refraction was measured semiannually for 4 years and annually thereafter. Right eye data were fit to individual Gompertz functions in participants with at least 6 years of follow-up and at least seven refraction measurements over 11 years. Function parameters were estimated using a nonlinear least squares procedure. Associated factors were evaluated using linear regression. Results. In total, 426 participants (91%) had valid Gompertz curve fits. The mean (SD) age at myopia stabilization was 15.61 (4.17) years, and the mean (SD) amount of myopia at stabilization was ?4.87 (2.01) D. Ethnicity (P < 0.0001) but not sex or the number of myopic parents was associated with the age at stabilization. Ethnicity (P = 0.02) and the number of myopic parents (P = 0.01) but not sex were associated with myopia magnitude at stabilization. At stabilization, African Americans were youngest (mean age, 13.82 years) and had the least myopia (mean, ?4.36 D). Participants with two versus no myopic parents had approximately 1.00 D more myopia at stabilization. The age and the amount of myopia at stabilization were correlated (r = ?0.60, P < 0.0001). Conclusions. The Gompertz function provides estimates of the age and the amount of myopia at stabilization in an ethnically diverse cohort. These findings should provide guidance on the time course of myopia and on decisions regarding the type and timing of interventions. PMID:24159085

  6. Fluence correction factors for graphite calorimetry in a low-energy clinical proton beam: I. Analytical and Monte Carlo simulations.

    PubMed

    Palmans, H; Al-Sulaiti, L; Andreo, P; Shipley, D; Lhr, A; Bassler, N; Martinkovi?, J; Dobrovodsk, J; Rossomme, S; Thomas, R A S; Kacperek, A

    2013-05-21

    The conversion of absorbed dose-to-graphite in a graphite phantom to absorbed dose-to-water in a water phantom is performed by water to graphite stopping power ratios. If, however, the charged particle fluence is not equal at equivalent depths in graphite and water, a fluence correction factor, kfl, is required as well. This is particularly relevant to the derivation of absorbed dose-to-water, the quantity of interest in radiotherapy, from a measurement of absorbed dose-to-graphite obtained with a graphite calorimeter. In this work, fluence correction factors for the conversion from dose-to-graphite in a graphite phantom to dose-to-water in a water phantom for 60 MeV mono-energetic protons were calculated using an analytical model and five different Monte Carlo codes (Geant4, FLUKA, MCNPX, SHIELD-HIT and McPTRAN.MEDIA). In general the fluence correction factors are found to be close to unity and the analytical and Monte Carlo codes give consistent values when considering the differences in secondary particle transport. When considering only protons the fluence correction factors are unity at the surface and increase with depth by 0.5% to 1.5% depending on the code. When the fluence of all charged particles is considered, the fluence correction factor is about 0.5% lower than unity at shallow depths predominantly due to the contributions from alpha particles and increases to values above unity near the Bragg peak. Fluence correction factors directly derived from the fluence distributions differential in energy at equivalent depths in water and graphite can be described by kfl = 0.9964 + 0.0024zw-eq with a relative standard uncertainty of 0.2%. Fluence correction factors derived from a ratio of calculated doses at equivalent depths in water and graphite can be described by kfl = 0.9947 + 0.0024zw-eq with a relative standard uncertainty of 0.3%. These results are of direct relevance to graphite calorimetry in low-energy protons but given that the fluence correction factor is almost solely influenced by non-elastic nuclear interactions the results are also relevant for plastic phantoms that consist of carbon, oxygen and hydrogen atoms as well as for soft tissues. PMID:23629423

  7. The value of Seasonal Correction Factors in assessing the health risk from domestic radon: a case study in Northamptonshire, UK.

    PubMed

    Denman, A R; Crockett, R G M; Groves-Kirkby, C J; Phillips, P S; Gillmore, G K; Woolridge, A C

    2007-01-01

    Following an intensive survey of domestic radon levels in the United Kingdom (UK), the former National Radiological Protection Board (NRPB), now the Radiation Protection Division of the Health Protection Agency (HPA-RPD), established a measurement protocol and promulgated Seasonal Correction Factors applicable to the country as a whole. Radon levels in the domestic built environment are assumed to vary systematically and repeatably during the year, being generally higher in winter. The Seasonal Correction Factors therefore comprise a series of numerical multipliers, which convert a 1-month or 3-month radon concentration measurement, commencing in any month of the year, to an effective annual mean radon concentration. In a recent project undertaken to assess the utility of short-term exposures in quantifying domestic radon levels, a comparative assessment of a number of integrating detector types was undertaken, with radon levels in 34 houses on common geology monitored over a 12-month period using dose-integrating track-etch detectors exposed in pairs (one upstairs, one downstairs) at 1-month and 3-month resolution. Seasonal variability of radon concentrations departed significantly from that expected on the basis of the HPA-RPD Seasonal Correction Factor set, with year-end discontinuities at both 1-month and 3-month measurement resolutions. Following this study, monitoring with electrets was continued in four properties, with weekly radon concentration data now available for a total duration in excess of three and a half years. Analysis of this data has permitted the derivation of reliable local Seasonal Correction Factors. Overall, these are significantly lower than those recommended by HPA-RPD, but are comparable with other results from the UK and from abroad, particularly those that recognise geological diversity and are consequently prepared on a regional rather than a national basis. This finding calls into question the validity of using nationally aggregated Seasonal Correction Factors, especially for shorter exposures, and the universal applicability of these corrections is discussed in detail. PMID:16899293

  8. Correction Factor for Determining the London Penetration Depth from Strip Resonators

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.

    1995-01-01

    A significant disagreement is often seen between the theoretical temperature dependent magnetic penetration depth profile and experimentally derived calculations based on stripline type resonators. This short paper shows that the disagreement can be attributed to the susceptance coupled into the resonator from the gap discontinuity as well as the feed line. When the effect is taken into account, the natural resonant frequency of the resonator is increased, and the frequency shift due to kinetic inductance can be calculated much more accurately. While it is necessary to include this effect to determine the penetration depth, it is shown that the impact on unloaded quality factor is generally negligible. The situation when the strip characteristic impedance is not matched to the generator is included.

  9. A Physically Based Algorithm for Non-Blackbody Correction of Cloud-Top Temperature and Application to Convection Study

    NASA Technical Reports Server (NTRS)

    Wang, Chunpeng; Lou, Zhengzhao Johnny; Chen, Xiuhong; Zeng, Xiping; Tao, Wei-Kuo; Huang, Xianglei

    2014-01-01

    Cloud-top temperature (CTT) is an important parameter for convective clouds and is usually different from the 11-micrometers brightness temperature due to non-blackbody effects. This paper presents an algorithm for estimating convective CTT by using simultaneous passive [Moderate Resolution Imaging Spectroradiometer (MODIS)] and active [CloudSat 1 Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)] measurements of clouds to correct for the non-blackbody effect. To do this, a weighting function of the MODIS 11-micrometers band is explicitly calculated by feeding cloud hydrometer profiles from CloudSat and CALIPSO retrievals and temperature and humidity profiles based on ECMWF analyses into a radiation transfer model.Among 16 837 tropical deep convective clouds observed by CloudSat in 2008, the averaged effective emission level (EEL) of the 11-mm channel is located at optical depth; approximately 0.72, with a standard deviation of 0.3. The distance between the EEL and cloud-top height determined by CloudSat is shown to be related to a parameter called cloud-top fuzziness (CTF), defined as the vertical separation between 230 and 10 dBZ of CloudSat radar reflectivity. On the basis of these findings a relationship is then developed between the CTF and the difference between MODIS 11-micrometers brightness temperature and physical CTT, the latter being the non-blackbody correction of CTT. Correction of the non-blackbody effect of CTT is applied to analyze convective cloud-top buoyancy. With this correction, about 70% of the convective cores observed by CloudSat in the height range of 6-10 km have positive buoyancy near cloud top, meaning clouds are still growing vertically, although their final fate cannot be determined by snapshot observations.

  10. Allometric Scaling of Therapeutic Monoclonal Antibodies Using Antigen Concentration as a Correction Factor: Application to the Human Clearance Prediction.

    PubMed

    Wang, Lei; Qiang, Wei; Cheng, Zeneng

    2016-03-01

    Allometric scaling has been widely used for predictions of human pharmacokinetic (PK) parameters in the development of monoclonal antibody (mAb) drugs, and some correction factors have been proposed to improve the estimations. However, classic correction factors fail to offer a complete explanation of the additional differences among species besides the body weight and, thus, lack enough power to further improve the predictions. In this study, the antigen concentration was initially set as a new correction factor to predict the human clearance (CL) of mAbs. Bevacizumab was intravenously injected into 2 animal species and humans to obtain PK data to predict human CL from the animal data. Additionally, a new approach was also validated with data from 3 other mAbs which were collected through a literature review of published work. Accordingly, allometric scaling with a correction factor of the antigen concentration generated accurate estimations of the human CL of 4 mAbs, which were superior to the results obtained by other classic scaling methods. More importantly, the proposed method also achieved good predictions of individual human CL of bevacizumab. In conclusion, the potential of this method as a powerful tool for human PK estimation of mAbs in species translation has been demonstrated. PMID:26886347

  11. Determination of the ion recombination correction factor for intraoperative electron beams.

    PubMed

    Ghorbanpour Besheli, Majid; Simiantonakis, Ioannis; Zink, Klemens; Budach, Wilfried

    2016-03-01

    The ion recombination correction factor (ks) is determined for the Advanced Markus chamber exposed to electron beams produced by a dedicated intraoperative radiation therapy (IORT) accelerator at medium dose-per-pulse values. The authors evaluate five different methods. Three of them are known as Boag's modified expressions, which are based on the two-voltage-analysis method and include the free-electron component. In the fourth method the IAEA TRS-398 protocol is applied, which uses the same two-voltage-analysis method but ignores the free-electron component, and finally the fifth approach is known as the Jaffé plot. ks values were obtained in the range of 4 mGy/pulse to 42 mGy/pulse and were compared with ks values determined by means of radiochromic films, which are independent of the dose rate. It was found that ks values that resulted from the three Boag's modified expressions and the TRS-398 protocol deviated by on average 1.5% and 1.4%, respectively, from the reference ks values based on film dosimetry. These results are within the estimated relative uncertainty of ±3%. On the other hand, the absolute deviation of each method depends on the dose-per-pulse value at which the method is investigated. In conclusion, in the medium dose-per-pulse range all Boag's modified expressions could be used for ks determination. Above a dose-per-pulse value of 35 mGy/pulse, the TRS-398 approach should be avoided. At 27 mGy/pulse and a maximum operation voltage of 300 V the ks value resulting from the Jaffé plot showed a 0.3% deviation from the reference value. More investigation on the Jaffé plot is necessary at higher dose-per-pulse values. PMID:26164499

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

    SciTech Connect

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

    2013-01-15

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

  13. Quantum corrections to temperature dependent electrical conductivity of ZnO thin films degenerately doped with Si

    SciTech Connect

    Das, Amit K. Ajimsha, R. S.; Kukreja, L. M.

    2014-01-27

    ZnO thin films degenerately doped with Si (Si{sub x}Zn{sub 1?x}O) in the concentrations range of ?0.5% to 5.8% were grown by sequential pulsed laser deposition on sapphire substrates at 400?C. The temperature dependent resistivity measurements in the range from 300 to 4.2?K revealed negative temperature coefficient of resistivity (TCR) for the 0.5%, 3.8%, and 5.8% doped Si{sub x}Zn{sub 1?x}O films in the entire temperature range. On the contrary, the Si{sub x}Zn{sub 1?x}O films with Si concentrations of 1.0%, 1.7%, and 2.0% showed a transition from negative to positive TCR with increasing temperature. These observations were explained using weak localization based quantum corrections to conductivity.

  14. Correction factors for on-line microprobe analysis of multielement alloy systems

    NASA Technical Reports Server (NTRS)

    Unnam, J.; Tenney, D. R.; Brewer, W. D.

    1977-01-01

    An on-line correction technique was developed for the conversion of electron probe X-ray intensities into concentrations of emitting elements. This technique consisted of off-line calculation and representation of binary interaction data which were read into an on-line minicomputer to calculate variable correction coefficients. These coefficients were used to correct the X-ray data without significantly increasing computer core requirements. The binary interaction data were obtained by running Colby's MAGIC 4 program in the reverse mode. The data for each binary interaction were represented by polynomial coefficients obtained by least-squares fitting a third-order polynomial. Polynomial coefficients were generated for most of the common binary interactions at different accelerating potentials and are included. Results are presented for the analyses of several alloy standards to demonstrate the applicability of this correction procedure.

  15. Shutterless solution for simultaneous focal plane array temperature estimation and nonuniformity correction in uncooled long-wave infrared camera.

    PubMed

    Cao, Yanpeng; Tisse, Christel-Loic

    2013-09-01

    In uncooled long-wave infrared (LWIR) microbolometer imaging systems, temperature fluctuations of the focal plane array (FPA) result in thermal drift and spatial nonuniformity. In this paper, we present a novel approach based on single-image processing to simultaneously estimate temperature variances of FPAs and compensate the resulting temperature-dependent nonuniformity. Through well-controlled thermal calibrations, empirical behavioral models are derived to characterize the relationship between the responses of microbolometer and FPA temperature variations. Then, under the assumption that strong dependency exists between spatially adjacent pixels, we estimate the optimal FPA temperature so as to minimize the global intensity variance across the entire thermal infrared image. We make use of the estimated FPA temperature to infer an appropriate nonuniformity correction (NUC) profile. The performance and robustness of the proposed temperature-adaptive NUC method are evaluated on realistic IR images obtained by a 640 × 512 pixels uncooled LWIR microbolometer imaging system operating in a significantly changed temperature environment. PMID:24085086

  16. 27 CFR 30.67 - Table 7, for correction of volume of spirituous liquors to 60 degrees Fahrenheit.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... temperature. Where the spirits to be corrected are of an odd temperature, one-half of the difference, if any... factor for next lower proof), or if it is also necessary to correct the factor because of odd...

  17. 27 CFR 30.67 - Table 7, for correction of volume of spirituous liquors to 60 degrees Fahrenheit.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... temperature. Where the spirits to be corrected are of an odd temperature, one-half of the difference, if any... factor for next lower proof), or if it is also necessary to correct the factor because of odd...

  18. 27 CFR 30.67 - Table 7, for correction of volume of spirituous liquors to 60 degrees Fahrenheit.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... temperature. Where the spirits to be corrected are of an odd temperature, one-half of the difference, if any... factor for next lower proof), or if it is also necessary to correct the factor because of odd...

  19. Temperature and stiffness correction of SAW devices for wireless strain sensing

    NASA Astrophysics Data System (ADS)

    Oppenheim, Irving J.; Carey, Nicola S.; Chin, T.-L.; Zheng, Peng; Greve, David W.

    2011-04-01

    Surface acoustic wave (SAW) devices are solid-state components in which a wave propagates along the surface of a piezoelectric material. Changes in strain or temperature cause shifts in the acoustic wave speed and/or the path length, enabling SAW devices to act as sensors. We present experimental studies on lithium niobate SAW devices acting as passively-powered devices. Sensitivity, reproducibility, and linearity are excellent when measuring strain at constant temperature, but the devices are also sensitive to temperature changes. We show experimental results of strain measurement incorporating temperature compensation.

  20. Fatigue Crack Growth Rate and Stress-Intensity Factor Corrections for Out-of-Plane Crack Growth

    NASA Technical Reports Server (NTRS)

    Forth, Scott C.; Herman, Dave J.; James, Mark A.

    2003-01-01

    Fatigue crack growth rate testing is performed by automated data collection systems that assume straight crack growth in the plane of symmetry and use standard polynomial solutions to compute crack length and stress-intensity factors from compliance or potential drop measurements. Visual measurements used to correct the collected data typically include only the horizontal crack length, which for cracks that propagate out-of-plane, under-estimates the crack growth rates and over-estimates the stress-intensity factors. The authors have devised an approach for correcting both the crack growth rates and stress-intensity factors based on two-dimensional mixed mode-I/II finite element analysis (FEA). The approach is used to correct out-of-plane data for 7050-T7451 and 2025-T6 aluminum alloys. Results indicate the correction process works well for high DeltaK levels but fails to capture the mixed-mode effects at DeltaK levels approaching threshold (da/dN approximately 10(exp -10) meter/cycle).

  1. Physical factors in cataractogenesis: ambient ultraviolet radiation and temperature

    SciTech Connect

    Sliney, D.H.

    1986-05-01

    A number of environmental cofactors have been implicated in cataracto-genesis. Two have received the greatest attention: ultraviolet radiation (UVR) and ambient temperature. Unfortunately, both temperature and UVR levels vary similarly with geographical latitude. Careful attention to several more refined physical variables and the geometry of exposure may permit investigators to separate the contributory effects of these two physical agents. This paper briefly reviews the available data, estimates the variation of lenticular temperature with ambient temperature, and provides measurements of short-wavelength (UV-B) UVR exposure to the human eye with different meterological conditions. The study attempts to provide epidemiological investigators with more detailed information necessary to perform more accurate studies of cataract and other ocular pathologies that appear to be related to environmental factors. Ocular UV-B radiation exposure levels were measured at nine locations in the USA near 40 degrees latitude at elevations from sea level to 8000 ft. Terrain reflectance is shown to be much more important than terrain elevation; cloud cover and haze may actually increase ocular exposure; and the value of wearing brimmed hats and spectacles varies with the environment. Several avenues for future research are suggested.

  2. Reference dosimetry condition and beam quality correction factor for CyberKnife beam

    SciTech Connect

    Kawachi, Toru; Saitoh, Hidetoshi; Inoue, Mitsuhiro; Katayose, Tetsurou; Myojoyama, Atsushi; Hatano, Kazuo

    2008-10-15

    This article is intended to improve the certainty of the absorbed dose determination for reference dosimetry in CyberKnife beams. The CyberKnife beams do not satisfy some conditions of the standard reference dosimetry protocols because of its unique treatment head structure and beam collimating system. Under the present state of affairs, the reference dosimetry has not been performed under uniform conditions and the beam quality correction factor k{sub Q} for an ordinary 6 MV linear accelerator has been temporally substituted for the k{sub Q} of the CyberKnife in many sites. Therefore, the reference conditions and k{sub Q} as a function of the beam quality index in a new way are required. The dose flatness and the error of dosimeter reading caused by radiation fields and detector size were analyzed to determine the reference conditions. Owing to the absence of beam flattening filter, the dose flatness of the CyberKnife beam was inferior to that of an ordinary 6 MV linear accelerator. And if the absorbed dose is measured with an ionization chamber which has cavity length of 2.4, 1.0 and 0.7 cm in reference dosimetry, the dose at the beam axis for a field of 6.0 cm collimator was underestimated 1.5%, 0.4%, and 0.2% on a calculation. Therefore, the maximum field shaped with a 6.0 cm collimator and ionization chamber which has a cavity length of 1.0 cm or shorter were recommended as the conditions of reference dosimetry. Furthermore, to determine the k{sub Q} for the CyberKnife, the realistic energy spectrum of photons and electrons in water was simulated with the BEAMnrc. The absence of beam flattening filter also caused softer photon energy spectrum than that of an ordinary 6 MV linear accelerator. Consequently, the k{sub Q} for ionization chambers of a suitable size were determined and tabulated as a function of measurable beam quality indexes in the CyberKnife beam.

  3. Separating temperature from other factors in phenological measurements

    NASA Astrophysics Data System (ADS)

    Schwartz, Mark D.; Hanes, Jonathan M.; Liang, Liang

    2014-09-01

    Phenological observations offer a simple and effective way to measure climate change effects on the biosphere. While some species in northern mixed forests show a highly sensitive site preference to microenvironmental differences (i.e., the species is present in certain areas and absent in others), others with a more plastic environmental response (e.g., Acer saccharum, sugar maple) allow provisional separation of the universal "background" phenological variation caused by in situ (possibly biological/genetic) variation from the microclimatic gradients in air temperature. Moran's I tests for spatial autocorrelation among the phenological data showed significant ( α ≤ 0.05) clustering across the study area, but random patterns within the microclimates themselves, with isolated exceptions. In other words, the presence of microclimates throughout the study area generally results in spatial autocorrelation because they impact the overall phenological development of sugar maple trees. However, within each microclimate (where temperature conditions are relatively uniform) there is little or no spatial autocorrelation because phenological differences are due largely to randomly distributed in situ factors. The phenological responses from 2008 and 2009 for two sugar maple phenological stages showed the relationship between air temperature degree-hour departure and phenological change ranged from 0.5 to 1.2 days earlier for each additional 100 degree-hours. Further, the standard deviations of phenological event dates within individual microclimates (for specific events and years) ranged from 2.6 to 3.8 days. Thus, that range of days is inferred to be the "background" phenological variation caused by factors other than air temperature variations, such as genetic differences between individuals.

  4. The effect of empirical-statistical correction of intensity-dependent model errors on the temperature climate change signal

    NASA Astrophysics Data System (ADS)

    Gobiet, A.; Suklitsch, M.; Heinrich, G.

    2015-10-01

    This study discusses the effect of empirical-statistical bias correction methods like quantile mapping (QM) on the temperature change signals of climate simulations. We show that QM regionally alters the mean temperature climate change signal (CCS) derived from the ENSEMBLES multi-model data set by up to 15 %. Such modification is currently strongly discussed and is often regarded as deficiency of bias correction methods. However, an analytical analysis reveals that this modification corresponds to the effect of intensity-dependent model errors on the CCS. Such errors cause, if uncorrected, biases in the CCS. QM removes these intensity-dependent errors and can therefore potentially lead to an improved CCS. A similar analysis as for the multi-model mean CCS has been conducted for the variance of CCSs in the multi-model ensemble. It shows that this indicator for model uncertainty is artificially inflated by intensity-dependent model errors. Therefore, QM also has the potential to serve as an empirical constraint on model uncertainty in climate projections. However, any improvement of simulated CCSs by empirical-statistical bias correction methods can only be realized if the model error characteristics are sufficiently time-invariant.

  5. Finite temperature application of the corrected propagator method to reactive dynamics in a condensed-phase environment

    PubMed Central

    Gelman, David; Schwartz, Steven D.

    2011-01-01

    The recently proposed mixed quantum-classical method is extended to applications at finite temperatures. The method is designed to treat complex systems consisting of a low-dimensional quantum part (the primary system) coupled to a dissipative bath described classically. The method is based on a formalism showing how to systematically correct the approximate zeroth-order evolution rule. The corrections are defined in terms of the total quantum Hamiltonian and are taken to the classical limit by introducing the frozen Gaussian approximation for the bath degrees of freedom. The evolution of the primary system is governed by the corrected propagator yielding the exact quantum dynamics. The method has been tested on a standard model system describing proton transfer in a condensed-phase environment: a symmetric double-well potential bilinearly coupled to a bath of harmonic oscillators. Flux correlation functions and thermal rate constants have been calculated at two different temperatures for a range of coupling strengths. The results have been compared to the fully quantum simulations of Topaler and Makri [J. Chem. Phys. 101, 7500 (1994)] with the real path integral method. PMID:21261332

  6. Voluntary STD testing and treatment program at a metropolitan correctional facility: evaluation of test acceptability and associated risk factors.

    PubMed

    Brown, Christopher K; Earley, Mary; Shaikh, Raees; Fickenscher, Jillian; Ott, Jessica; Person, Austin; Islam, K M Monirul; Simonsen, Kari; Sandkovsky, Uriel; Kaiser, Katherine Laux; Foxall, Mark; Margalit, Ruth

    2014-01-01

    Few studies have addressed challenges of diagnosis and treatment of sexually transmitted diseases (STDs) within correctional facilities. Initiatives that screen all inmates can be cost-prohibitive, while symptom-based screening undoubtedly fails to recognize significant numbers of asymptomatically infected persons. This study discusses a voluntary STD screening and treatment program developed at the Douglas County (Nebraska) Department of Corrections where student volunteers interviewed, screened, and educated 456 inmates. Inmate urine samples and interview responses about risk behaviors and motivators for participation in the screening program were analyzed. The results support the ongoing project method to screen and treat inmates in the community correctional facility. Risk factor analysis suggests that targeted testing and treatment efforts may have a role in providing cost-effective care for STD among the incarcerated population. PMID:24352406

  7. Recovery and radiation corrections and time constants of several sizes of shielded and unshielded thermocouple probes for measuring gas temperature

    NASA Technical Reports Server (NTRS)

    Glawe, G. E.; Holanda, R.; Krause, L. N.

    1978-01-01

    Performance characteristics were experimentally determined for several sizes of a shielded and unshielded thermocouple probe design. The probes are of swaged construction and were made of type K wire with a stainless steel sheath and shield and MgO insulation. The wire sizes ranged from 0.03- to 1.02-mm diameter for the unshielded design and from 0.16- to 0.81-mm diameter for the shielded design. The probes were tested through a Mach number range of 0.2 to 0.9, through a temperature range of room ambient to 1420 K, and through a total-pressure range of 0.03 to 0.2.2 MPa (0.3 to 22 atm). Tables and graphs are presented to aid in selecting a particular type and size. Recovery corrections, radiation corrections, and time constants were determined.

  8. Single-image-based solution for optics temperature-dependent nonuniformity correction in an uncooled long-wave infrared camera.

    PubMed

    Cao, Yanpeng; Tisse, Christel-Loic

    2014-02-01

    In this Letter, we propose an efficient and accurate solution to remove temperature-dependent nonuniformity effects introduced by the imaging optics. This single-image-based approach computes optics-related fixed pattern noise (FPN) by fitting the derivatives of correction model to the gradient components, locally computed on an infrared image. A modified bilateral filtering algorithm is applied to local pixel output variations, so that the refined gradients are most likely caused by the nonuniformity associated with optics. The estimated bias field is subtracted from the raw infrared imagery to compensate the intensity variations caused by optics. The proposed method is fundamentally different from the existing nonuniformity correction (NUC) techniques developed for focal plane arrays (FPAs) and provides an essential image processing functionality to achieve completely shutterless NUC for uncooled long-wave infrared (LWIR) imaging systems. PMID:24487887

  9. TEMPERATURE CORRECTION FORMULAE FOR ADJUSTING ESTIMATES OF EMISSIONS FROM AUTOMOBILES. VOLUME I

    EPA Science Inventory

    This report describes an analysis of the effects of temperature on the emissions of hydrocarbons, carbon monoxide, and oxides of nitrogen from autombiles. The analysis was conducted by Vector Research, Incorporated, (VRI) For the Environmental Protection Agency (EPA). The analysi...

  10. Experimental determination of field factors ([Formula: see text]) for small radiotherapy beams using the daisy chain correction method.

    PubMed

    Lárraga-Gutiérrez, José Manuel

    2015-08-01

    Recently, Alfonso et al proposed a new formalism for the dosimetry of small and non-standard fields. The proposed new formalism is strongly based on the calculation of detector-specific beam correction factors by Monte Carlo simulation methods, which accounts for the difference in the response of the detector between the small and the machine specific reference field. The correct calculation of the detector-specific beam correction factors demands an accurate knowledge of the linear accelerator, detector geometry and composition materials. The present work shows that the field factors in water may be determined experimentally using the daisy chain correction method down to a field size of 1 cm × 1 cm for a specific set of detectors. The detectors studied were: three mini-ionization chambers (PTW-31014, PTW-31006, IBA-CC01), three silicon-based diodes (PTW-60018, IBA-SFD and IBA-PFD) and one synthetic diamond detector (PTW-60019). Monte Carlo simulations and experimental measurements were performed for a 6 MV photon beam at 10 cm depth in water with a source-to-axis distance of 100 cm. The results show that the differences between the experimental and Monte Carlo calculated field factors are less than 0.5%-with the exception of the IBA-PFD-for field sizes between 1.5 cm × 1.5 cm and 5 cm × 5 cm. For the 1 cm × 1 cm field size, the differences are within 2%. By using the daisy chain correction method, it is possible to determine measured field factors in water. The results suggest that the daisy chain correction method is not suitable for measurements performed with the IBA-PFD detector. The latter is due to the presence of tungsten powder in the detector encapsulation material. The use of Monte Carlo calculated [Formula: see text] is encouraged for field sizes less than or equal to 1 cm × 1 cm for the dosimeters used in this work. PMID:26161448

  11. Critical Factors in Mental Health Programming for Juveniles in Corrections Facilities

    ERIC Educational Resources Information Center

    Underwood, Lee A.; Phillips, Annie; von Dresner, Kara; Knight, Pamela D.

    2006-01-01

    Juveniles with mental health and other specialized needs are overrepresented in the juvenile justice system, and while juvenile corrections have not historically provided standardized and evidence-based mental health services for its incarcerated youth, the demand is evident. The reality is that juveniles with serious mental illness are committed…

  12. Comprehensive wind correction for a Rayleigh Doppler lidar from atmospheric temperature and pressure influences and Mie contamination

    NASA Astrophysics Data System (ADS)

    Shangguan, Ming-Jia; Xia, Hai-Yun; Dou, Xian-Kang; Wang, Chong; Qiu, Jia-Wei; Zhang, Yun-Peng; Shu, Zhi-Feng; Xue, Xiang-Hui

    2015-09-01

    A correction considering the effects of atmospheric temperature, pressure, and Mie contamination must be performed for wind retrieval from a Rayleigh Doppler lidar (RDL), since the so-called Rayleigh response is directly related to the convolution of the optical transmission of the frequency discriminator and the Rayleigh-Brillouin spectrum of the molecular backscattering. Thus, real-time and on-site profiles of atmospheric pressure, temperature, and aerosols should be provided as inputs to the wind retrieval. Firstly, temperature profiles under 35 km and above the altitude are retrieved, respectively, from a high spectral resolution lidar (HSRL) and a Rayleigh integration lidar (RIL) incorporating to the RDL. Secondly, the pressure profile is taken from the European Center for Medium range Weather Forecast (ECMWF) analysis, while radiosonde data are not available. Thirdly, the Klett-Fernald algorithms are adopted to estimate the Mie and Rayleigh components in the atmospheric backscattering. After that, the backscattering ratio is finally determined in a nonlinear fitting of the transmission of the atmospheric backscattering through the Fabry-Perot interferometer (FPI) to a proposed model. In the validation experiments, wind profiles from the lidar show good agreement with the radiosonde in the overlapping altitude. Finally, a continuous wind observation shows the stability of the correction scheme. Project supported by the National Natural Science Foundation of China (Grant Nos. 41174131, 41274151, 41304123, 41121003 and 41025016).

  13. Monte Carlo calculation of beam quality correction factors in proton beams using detailed simulation of ionization chambers.

    PubMed

    Gomà, Carles; Andreo, Pedro; Sempau, Josep

    2016-03-21

    This work calculates beam quality correction factors (k Q ) in monoenergetic proton beams using detailed Monte Carlo simulation of ionization chambers. It uses the Monte Carlo code penh and the electronic stopping powers resulting from the adoption of two different sets of mean excitation energy values for water and graphite: (i) the currently ICRU 37 and ICRU 49 recommended [Formula: see text] and [Formula: see text] and (ii) the recently proposed [Formula: see text] and [Formula: see text]. Twelve different ionization chambers were studied. The k Q factors calculated using the two different sets of I-values were found to agree with each other within 1.6% or better. k Q factors calculated using current ICRU I-values were found to agree within 2.3% or better with the k Q factors tabulated in IAEA TRS-398, and within 1% or better with experimental values published in the literature. k Q factors calculated using the new I-values were also found to agree within 1.1% or better with the experimental values. This work concludes that perturbation correction factors in proton beams-currently assumed to be equal to unity-are in fact significantly different from unity for some of the ionization chambers studied. PMID:26943497

  14. Small field diode correction factors derived using an air core fibre optic scintillation dosimeter and EBT2 film.

    PubMed

    Ralston, Anna; Liu, Paul; Warrener, Kirbie; McKenzie, David; Suchowerska, Natalka

    2012-05-01

    There is no commercially available real-time dosimeter that can accurately measure output factors for field sizes down to 4 mm without the use of correction factors. Silicon diode detectors are commonly used but are not dosimetrically water equivalent, resulting in energy dependence and fluence perturbation. In contrast, plastic scintillators are nearly dosimetrically water equivalent. A fibre optic dosimeter (FOD) with a 0.8 mm(3) plastic scintillator coupled to an air core light guide was used to measure the output factors for Novalis/BrainLab stereotactic cones of diameter 4-30 mm and Novalis MLC fields of width 5-100 mm. The FOD data matched the output factors measured by a 0.125 cm(3) Semiflex ion chamber for the MLC fields above 30 mm and those measured with the EBT2 radiochromic film for the cones and MLC fields below 30 mm. Relative detector readings were obtained with four diode types (IBA SFD, EFD, PFD, PTW 60012) for the same fields. Empirical diode correction factors were determined by taking the ratio of FOD output factors to diode relative detector readings. The diodes were found to over-respond by 3%-16% for the smallest field. There was good agreement between different diodes of the same model number. PMID:22505592

  15. Monte Carlo calculation of beam quality correction factors in proton beams using detailed simulation of ionization chambers

    NASA Astrophysics Data System (ADS)

    Gomà, Carles; Andreo, Pedro; Sempau, Josep

    2016-03-01

    This work calculates beam quality correction factors (k Q ) in monoenergetic proton beams using detailed Monte Carlo simulation of ionization chambers. It uses the Monte Carlo code penh and the electronic stopping powers resulting from the adoption of two different sets of mean excitation energy values for water and graphite: (i) the currently ICRU 37 and ICRU 49 recommended {{I}\\text{w}}=75~\\text{eV} and {{I}\\text{g}}=78~\\text{eV} and (ii) the recently proposed {{I}\\text{w}}=78~\\text{eV} and {{I}\\text{g}}=81.1~\\text{eV} . Twelve different ionization chambers were studied. The k Q factors calculated using the two different sets of I-values were found to agree with each other within 1.6% or better. k Q factors calculated using current ICRU I-values were found to agree within 2.3% or better with the k Q factors tabulated in IAEA TRS-398, and within 1% or better with experimental values published in the literature. k Q factors calculated using the new I-values were also found to agree within 1.1% or better with the experimental values. This work concludes that perturbation correction factors in proton beams—currently assumed to be equal to unity—are in fact significantly different from unity for some of the ionization chambers studied.

  16. Method to determine the position-dependant metal correction factor for dose-rate equivalent laser testing of semiconductor devices

    DOEpatents

    Horn, Kevin M.

    2013-07-09

    A method reconstructs the charge collection from regions beneath opaque metallization of a semiconductor device, as determined from focused laser charge collection response images, and thereby derives a dose-rate dependent correction factor for subsequent broad-area, dose-rate equivalent, laser measurements. The position- and dose-rate dependencies of the charge-collection magnitude of the device are determined empirically and can be combined with a digital reconstruction methodology to derive an accurate metal-correction factor that permits subsequent absolute dose-rate response measurements to be derived from laser measurements alone. Broad-area laser dose-rate testing can thereby be used to accurately determine the peak transient current, dose-rate response of semiconductor devices to penetrating electron, gamma- and x-ray irradiation.

  17. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in degrees...

  18. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in...

  19. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in...

  20. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in...

  1. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in degrees...

  2. Correct determination of low-temperature free-exciton diffusion profiles in GaAs

    NASA Astrophysics Data System (ADS)

    Bieker, S.; Kiessling, T.; Ossau, W.; Molenkamp, L. W.

    2015-09-01

    We report on low-temperature spatially resolved photoluminescence (SRPL) experiments to study the diffusion of free excitons in a 1.5 -? m -thick layer of high-purity epitaxial GaAs. Extending previous SRPL experiments, we analyze the stationary diffusion profiles detected on the second LO-phonon replica of the free exciton. This allows us to circumvent the inherent interpretation ambiguities of the free-exciton zero-phonon line. Moreover, a spatially resolved line shape analysis of the (F X ) -2 ? ?LO replica provides direct experimental access to the pump-induced exciton temperature profile. We demonstrate that only resonant optical excitation prevents the buildup of a temperature gradient in the carrier system, which otherwise severely distorts the stationary and time-resolved free-exciton diffusion profiles.

  3. Conversion and correction factors for historical measurements of Iodine-131 in Hanford-area vegetation, 1945--1947: Draft

    SciTech Connect

    Mart, E.I.; Denham, D.H.; Thiede, M.E.

    1993-05-01

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the US Department of Energy's (DOE) Hanford Site near Richland, Washington. The report describes in detail the reconstructed conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation which was collected from the beginning of October 1945 through the end of December 1947.

  4. Quantum corrections to resistance of microblock tellurium at ultralow temperatures under phonon freezing conditions

    SciTech Connect

    Farbshtein, I. I. Chernyaev, A. V.; Shamshur, D. V.; Averkiev, N. S.

    2010-08-15

    The low-temperature magnetoresistance of bulk tellurium samples with a microcrystalline structure is investigated. At ultralow temperatures T {<=} 1 K, an anomalous positive magnetoresistance (APMR), viz. the antilocalization effect, is observed. It is shown that this effect can be explained using the weak localization theory. The characteristic parameters of the theory are determined. It is concluded that charge carriers produce a predominant effect on the phase breakdown time in the APMR mode of elastic scattering from structure defects, which leads to intervalley transitions without spin flip.

  5. Photon beam quality correction factors for the NE2571A and NE2581A thimble ionization chambers using PENELOPE.

    PubMed

    Erazo, Fabián; Lallena, Antonio M

    2016-01-01

    The beam quality correction factor [Formula: see text] and the perturbation factor pQ for photon beams were calculated for the NE2571A and NE2581A ionization chambers, using the Monte Carlo simulation code PENELOPE. Results are compared to those quoted for the NE2571 and NE2581 chambers in previous works. Both [Formula: see text] and pQ obtained for NE2571A and NE2581A chambers agree with those of their predecessors NE2571 and NE2581 ones. PMID:26602965

  6. Influence of Clinical Factors and Magnification Correction on Normal Thickness Profiles of Macular Retinal Layers Using Optical Coherence Tomography

    PubMed Central

    Higashide, Tomomi; Ohkubo, Shinji; Hangai, Masanori; Ito, Yasuki; Shimada, Noriaki; Ohno-Matsui, Kyoko; Terasaki, Hiroko; Sugiyama, Kazuhisa; Chew, Paul; Li, Kenneth K. W.; Yoshimura, Nagahisa

    2016-01-01

    Purpose To identify the factors which significantly contribute to the thickness variabilities in macular retinal layers measured by optical coherence tomography with or without magnification correction of analytical areas in normal subjects. Methods The thickness of retinal layers {retinal nerve fiber layer (RNFL), ganglion cell layer plus inner plexiform layer (GCLIPL), RNFL plus GCLIPL (ganglion cell complex, GCC), total retina, total retina minus GCC (outer retina)} were measured by macular scans (RS-3000, NIDEK) in 202 eyes of 202 normal Asian subjects aged 20 to 60 years. The analytical areas were defined by three concentric circles (1-, 3- and 6-mm nominal diameters) with or without magnification correction. For each layer thickness, a semipartial correlation (sr) was calculated for explanatory variables including age, gender, axial length, corneal curvature, and signal strength index. Results Outer retinal thickness was significantly thinner in females than in males (sr2, 0.07 to 0.13) regardless of analytical areas or magnification correction. Without magnification correction, axial length had a significant positive sr with RNFL (sr2, 0.12 to 0.33) and a negative sr with GCLIPL (sr2, 0.22 to 0.31), GCC (sr2, 0.03 to 0.17), total retina (sr2, 0.07 to 0.17) and outer retina (sr2, 0.16 to 0.29) in multiple analytical areas. The significant sr in RNFL, GCLIPL and GCC became mostly insignificant following magnification correction. Conclusions The strong correlation between the thickness of inner retinal layers and axial length appeared to result from magnification effects. Outer retinal thickness may differ by gender and axial length independently of magnification correction. PMID:26814541

  7. Impacts of climate change on temperature, precipitation and hydrology in Finland - studies using bias corrected Regional Climate Model data

    NASA Astrophysics Data System (ADS)

    Olsson, T.; Jakkila, J.; Veijalainen, N.; Backman, L.; Kaurola, J.; Vehvilinen, B.

    2015-07-01

    Assessment of climate change impacts on climate and hydrology on catchment scale requires reliable information about the average values and climate fluctuations of the past, present and future. Regional climate models (RCMs) used in impact studies often produce biased time series of meteorological variables. In this study bias correction (BC) of RCM temperature and precipitation for Finland is carried out using different versions of the distribution based scaling (DBS) method. The DBS-adjusted RCM data are used as input of a hydrological model to simulate changes in discharges of four study catchments in different parts of Finland. The annual mean discharges and seasonal variation simulated with the DBS-adjusted temperature and precipitation data are sufficiently close to observed discharges in the control period 1961-2000 and produce more realistic projections for mean annual and seasonal changes in discharges than the uncorrected RCM data. Furthermore, with most scenarios the DBS method used preserves the temperature and precipitation trends of the uncorrected RCM data during 1961-2100. However, if the biases in the mean or the standard deviation of the uncorrected temperatures are large, significant biases after DBS adjustment may remain or temperature trends may change, increasing the uncertainty of climate change projections. The DBS method influences especially the projected seasonal changes in discharges and the use of uncorrected data can produce unrealistic seasonal discharges and changes. The projected changes in annual mean discharges are moderate or small, but seasonal distribution of discharges will change significantly.

  8. Impacts of climate change on temperature, precipitation and hydrology in Finland - studies using bias corrected Regional Climate Model data

    NASA Astrophysics Data System (ADS)

    Olsson, T.; Jakkila, J.; Veijalainen, N.; Backman, L.; Kaurola, J.; Vehvilinen, B.

    2015-03-01

    Assessment of climate change impacts on climate and hydrology on catchment scale requires reliable information about the average values and climate fluctuations of the past, present and future. Regional Climate Models (RCMs) used in impact studies often produce biased time series of meteorological variables. In this study bias correction of RCM temperature and precipitation for Finland is carried out using different versions of distribution based scaling (DBS) method. The DBS adjusted RCM data is used as input of a hydrological model to simulate changes in discharges in four study catchments in different parts of Finland. The annual mean discharges and seasonal variation simulated with the DBS adjusted temperature and precipitation data are sufficiently close to observed discharges in the control period (1961-2000) and produce more realistic projections for mean annual and seasonal changes in discharges than the uncorrected RCM data. Furthermore, with most scenarios the DBS method used preserves the temperature and precipitation trends of the uncorrected RCM data during 1961-2100. However, if the biases in the mean or the SD of the uncorrected temperatures are large, significant biases after DBS adjustment may remain or temperature trends may change, increasing the uncertainty of climate change projections. The DBS method influences especially the projected seasonal changes in discharges and the use of uncorrected data can produce unrealistic seasonal discharges and changes. The projected changes in annual mean discharges are moderate or small, but seasonal distribution of discharges will change significantly.

  9. Influence and correction of temperature on optical measurement for fat and protein contents in a complex food model system

    NASA Astrophysics Data System (ADS)

    Zhang, Xuedian; Chang, Min; Xu, Kexin

    2009-11-01

    Near infrared spectroscopy has been proposed as an effective way for measuring complex component compositions noninvasively. However temperature-induced spectral variation can cause accuracy problems if not taken care of in a proper manner. The influence of temperature on optical measurements has been studied for determining fat and protein contents in complex food systems. A model system consisting of mixtures of fat, protein, water and emulsion was developed to create an imitation of complex food systems. The changes in optical properties, including the absorbance coefficients and reduced scattering coefficients, of the system from 25C to 40C were measured in the wavelength from 1100 to 1670 nm. Complex changes in the absorbance coefficient and decreasing changes in the reduced scattering coefficients with the increasing temperature were founded. The mechanisms of the influences were analyzed. In order to correct the effect, a statistical method was needed. Then, a method called global robust temperature calibration model is proposed. Accordingly, the validating experiments using the samples made up of 54 complex food systems were executed. The experimental results indicated that the method can significantly reduce the temperature effect on optical measurement.

  10. Factors affecting characterization of bulk high-temperature superconductors

    SciTech Connect

    Hull, J.R.

    1997-11-01

    Three major factors affect the characterization of bulk high-temperature superconductors in terms of their levitation properties during interaction with permanent magnets. First, the appropriate parameter for the permanent magnet is internal magnetization, not the value of the magnetic field measured at the magnet`s surface. Second, although levitation force grows with superconductor thickness and surface area, for a given permanent magnet size, comparison of levitation force between samples is meaningful when minimum values are assigned to the superconductor size parameters. Finally, the effect of force creep must be considered when time-averaging the force measurements. In addition to levitational force, the coefficient of friction of a levitated rotating permanent magnet may be used to characterize the superconductor.

  11. Correction Factors Applied to Finger Dosimetry: A Theoretical Assessment of Appropriate Values for Use in Handling Radiopharmaceuticals

    SciTech Connect

    Sherbini, Sami; Ilas, Dan; Eckerman, Keith F; DeCicco, Joseph

    2011-01-01

    United States Nuclear Regulatory Commission (USNRC) regulations limit the dose to the skin to 500 mSv per year. This is also the dose limit recommended by the International Commission on Radiological Protection (ICRP). The operational quantity recommended by ICRP for quantifying dose to the skin is the personal dose equivalent, Hp(0.07) and is identical to NRC s shallow dose equivalent, Hs, also measured at a skin depth of 7 mg cm 2. However, whereas ICRP recommends averaging the dose to the skin over an area of 1 cm2 regardless of the size of the exposed area of skin, USNRC requires the shallow dose equivalent to be averaged over 10 cm2. To monitor dose to the skin of the hands of workers handling radioactive materials and particularly in radiopharmaceutical manufacturing facilities, which is the focus of this work, workers are frequently required to wear finger ring dosimeters. The dosimeters monitor the dose at the location of the sensitive element, but this is not the dose required to show compliance (i.e., the dose averaged over the highest exposed contiguous 10 cm2 of skin). Therefore, it may be necessary to apply a correction factor that enables estimation of the required skin dose from the dosimeter reading. This work explored the effects of finger ring placement and of the geometry of the radioactive materials being handled by the worker on the relationship between the dosimeter reading and the desired average dose. A mathematical model of the hand was developed for this purpose that is capable of positioning the fingers in any desired grasping configuration, thereby realistically modeling manipulation of any object. The model was then used with the radiation transport code MCNP to calculate the dose distribution on the skin of the hand when handling a variety of radioactive vials and syringes, as well as the dose to the dosimeter element. Correction factors were calculated using the results of these calculations and examined for any patterns that may be useful in establishing an appropriate correction factor for this type of work. It was determined that a correction factor of one applied to the dosimeter reading, with the dosimeter placed at the base of the middle finger, provides an adequate estimate of the required average dose during a monitoring period for most commonly encountered geometries. Different correction factors may be required for exceptional or unusual source geometries and must be considered on a case-by-case basis.

  12. SU-E-T-464: On the Equivalence of the Quality Correction Factor for Pencil Beam Scanning Proton Therapy

    SciTech Connect

    Sorriaux, J; Paganetti, H; Testa, M; Giantsoudi, D; Schuemann, J; Bertrand, D; Orban de Xivry, J.; Lee, J; Palmans, H; Vynckier, S; Sterpin, E

    2014-06-01

    Purpose: In current practice, most proton therapy centers apply IAEA TRS-398 reference dosimetry protocol. Quality correction factors (kQ) take into account in the dose determination process the differences in beam qualities used for calibration unit and for treatment unit. These quality correction factors are valid for specific reference conditions. TRS-398 reference conditions should be achievable in both scattered proton beams (i.e. DS) and scanned proton beams (i.e. PBS). However, it is not a priori clear if TRS-398 kQ data, which are based on Monte Carlo (MC) calculations in scattered beams, can be used for scanned beams. Using TOPAS-Geant4 MC simulations, the study aims to determine whether broad beam quality correction factors calculated in TRS-398 can be directly applied to PBS delivery modality. Methods: As reference conditions, we consider a 10×10×10 cm{sup 3} homogeneous dose distribution delivered by PBS system in a water phantom (32/10 cm range/modulation) and an air cavity placed at the center of the spread-out-Bragg-peak. In order to isolate beam differences, a hypothetical broad beam is simulated. This hypothetical beam reproduces exactly the same range modulation, and uses the same energy layers than the PBS field. Ion chamber responses are computed for the PBS and hypothetical beams and then compared. Results: For an air cavity of 2×2×0.2 cm{sup 3}, the ratio of ion chamber responses for the PBS and hypothetical beam qualities is 0.9991 ± 0.0016. Conclusion: Quality correction factors are insensitive to the delivery pattern of the beam (broad beam or PBS), as long as similar dose distributions are achieved. This investigation, for an air cavity, suggests that broad beam quality correction factors published in TRS-398 can be applied for scanned beams. J. Sorriaux is financially supported by a public-private partnership involving the company Ion Beam Applications (IBA)

  13. Magnetic field corrections to the repulsive Casimir effect at finite temperature

    NASA Astrophysics Data System (ADS)

    Erdas, Andrea

    2016-02-01

    I investigate the finite temperature Casimir effect for a charged and massless scalar field satisfying mixed (Dirichlet-Neumann) boundary conditions on a pair of plane parallel plates of infinite size. The effect of a uniform magnetic field, perpendicular to the plates, on the Helmholtz free energy and Casimir pressure is studied. The ζ-function regularization technique is used to obtain finite results. Simple analytic expressions are obtained for the zeta function and the free energy, in the limits of small plate distance, high temperature and strong magnetic field. The Casimir pressure is obtained in each of the three limits and the situation of a magnetic field present between and outside the plates, as well as that of a magnetic field present only between the plates is examined. It is discovered that, in the small plate distance and high temperature limits, the repulsive pressure is less when the magnetic field is present between the plates but not outside, than it is when the magnetic field is present between and outside the plates.

  14. A Fourier approach for estimating and correcting the topographic perturbation of low-temperature thermochronological data

    NASA Astrophysics Data System (ADS)

    Glotzbach, C.; Braun, J.; van der Beek, P.

    2015-05-01

    Thermochronology is a unique tool to reconstruct the long-term exhumation history of outcropping rocks. Pronounced (palaeo-) topography can markedly perturb near-surface isotherms, which can result in erroneous exhumation histories derived from age-elevation relationships but also offers the possibility to reconstruct palaeo-topography. Here we use a synthetic dataset to illustrate the complex non-linear relationships between the degree of topographic perturbation of thermochronological ages on one hand, and exhumation rate, geothermal gradient, and topographic wavelength and relief on the other. The dataset reveals that, in theory, relief changes can be retrieved for wavelengths as low as 5 km, and wavelength changes are possible to detect for relief as low as 0.5 km. In addition, the data attest that even in regions characterised by very slow exhumation rates (e.g. 0.03 km/Ma), changes in palaeo-topography can be successfully retrieved. Coupling of this dataset with a Fast Fourier Transform (FFT) algorithm to decompose complex 2D topography into sinusoidal functions allows a rapid and accurate estimation of the topographic perturbation and resulting thermochronological ages assuming steady-state exhumation. This coupled method was successfully implemented to (i) predict most promising sample sites for the estimation of palaeo-topography and (ii) correct exhumation rates derived from non-vertical age-elevation profiles.

  15. A proposed correction of a systematic bias in early instrumental temperature series in Central Europe.

    NASA Astrophysics Data System (ADS)

    Bhm, R.; Jones, P. D.; Hiebl, J.; Frank, D.; Brunetti, M.; Maugeri, M.

    2009-04-01

    The instrumental period in climatology usually is regarded to have started shortly after the mid 19th century. Respective benchmarks are the starting point of the global mean temperature timeseries in the 1850s or the founding of many of the national meteorological services in the following 2 to 3 decades. But there is a considerable and valuable amount of measured climate data decades to a century earlier. The added value of having another century of directly measured climate information is great, particularly as these data bridge the pre-anthropogenic to anthropogenic forcing eras. But the demands on these early instrumental data in terms of their comparability with modern data are increasingly difficult to fulfil progressively back in time. Decreasing network density makes mathematical homogeneity testing and adjusting less reliable and the equipment as well as the measuring and data processing philosophy were in some aspects rather different to the recent one. The proposed contribution shows one of these "early instrumental" (EI) problems and proposes a solution for a region which may be regarded the richest in EI-data globally. Instrumental temperature recording in the Greater Alpine Region (GAR, 4-19E, 43-49N) began in the year 1760. Prior to the 1850-1870 period, after which screens of different types protected the instruments, thermometers were insufficiently sheltered from direct sunlight so were normally placed on north-facing walls or windows. It is likely that temperatures recorded in the summer half of the year were biased warm and those in the winter half biased cold, with the summer effect dominating. Because the changeover to screens often occurred at similar times, it has been difficult to determine the scale of the problem through relative homogeneity testing, as all neighbour sites were likely to be similarly affected. This study uses simultaneous measurements taken for eight recent years at the old and modern site at Kremsmnster, Austria to assess the issue. The temperature differences between the two locations (screened and unscreened) have caused a change in the diurnal cycle, which depends on the time of year. Using the orientation angle of the buildings (sites across the GAR in the range from NE to NW) different adjustments to the diurnal cycle are developed for each location. The effect on the 32 sites across the GAR varies due to different formulae being used by NMSs to calculate monthly means from the two or more observations made at each site each day. These formulae also changed over the years, so considerable amounts of additional metadata have had to be collected to apply the adjustments across the whole network. Overall, the results indicate that summer (April to September) average temperatures are cooled by about 0.4C before 1850, with winters (October to March) staying much the same. The effects on monthly temperature averages are largest in June (a cooling from 0.21 to 0.93C, depending on location) to a slight warming (up to 0.3C) of some sites in February. In addition to revising the temperature evolution during the past centuries, the results have important implications for the calibration of proxy climatic data in the region (such as tree ring indices and documentary data such as grape harvest dates). A difference series across the 32 sites in the GAR indicates that summers since 1760 have warmed by about 1C less than winters.

  16. [Measurement of peak correction factor of Farmer chamber for calibration of flattening filter free (FFF) clinical photon beams].

    PubMed

    Kontra, Gábor; Major, Tibor; Polgár, Csaba

    2015-06-01

    Farmer-type ionization chambers are considered the most reliable detectors and for this reason they are most frequently used for the calibration of photon beams of medical linear accelerators. Flattening filter free (FFF) photon beams of linear accelerators have recently started to be used in radiotherapy. The dose profile of FFF beams is peaked in the center of the field and the dose distribution will be inhomogeneous along the axis of the 2.3 cm long measuring volume of the Farmer chamber. The peaked radiation field will result in volume averaging effects in the large Farmer chamber, therefore this chamber will underestimate the true central axis dose. Our objective was to determine the value of the peak correction factor (Kp) of Farmer-type chamber with measurements to avoid the underestimation of the central axis dose during the calibration of FFF radiation fields. Measurements were made with 6 MV and 10 MV flattened (6X and 10X) and FFF beams (6XFFF and 10XFFF) of a Varian TrueBeam medical linear accelerator in a solid water phantom at 10 cm depth. The source surface distance (SSD) was 100 cm, the field size was 10×10 cm and the dose rate was always 400 MU/min during the measurements. We delivered 100 MU in each measurement and the absorbed dose to water was calculated according to the IAEA TRS-398 dosimetry protocol. The measured signals of the ionization chambers were always corrected for the ion recombination loss. The ion recombination correction factors (Kr) were determined with the two-voltage method separately for the used ion chambers and for flattened and unflattened beams. First, we measured the dose to water with PTW TM30012 Farmer chamber in 6XFFF and 6X beams, then calculated the ratio of doses of 6XFFF and 6X beams (R6,Farmer). Immediately after this we repeated the above measurements with PTW TM31010 Semiflex chamber and determined the ratio of doses of 6XFFF and 6X beams again (R6,Semiflex). The length of the sensitive volume of the Semiflex chamber is only 6.5 mm. According to our dose profile measurements the peak correction factor of this chamber equals to unity for both photon energies. As a consequence R6,Semiflex is larger than R6,Farmer and Kp6XFFF = R6,Semiflex / R6,Farmer, where Kp6XFFF is the peak correction factor of the Farmer chamber in 6XFFF beam. The advantage of this method is that we have to calculate ratio of doses, so it is not necessary to know the calibration factors of the chambers. Repeating the above measurements with 10X and 10XFFF beams we determined the peak correction factor of Farmer chamber for 10XFFF beam, too (Kp10XFFF). According to our measurements Kp6XFFF = 1.0025 and Kp10XFFF = 1.009. The bigger peak correction factor for 10XFFF beam is in accordance with the fact that the peak of dose profile is steeper for higher photon energy. The above described method for the determination of Kp can be used for other photon energies and other large volume ionization chambers. PMID:26035159

  17. Factors related to correctional facility incarceration among active injection drug users in Baltimore, MD

    PubMed Central

    Severtson, Stevan Geoffrey; Latimer, William W.

    2009-01-01

    Aim We investigated the moderating effect of impulse control on the association between drug use and incarceration among active injection drug users (IDU). Methods The study sample consisted of 282 IDUs aged 15 to 50 years from the Baltimore metropolitan region who reported injection drug use within the past 6 months and indicated that heroin or speedball was their drug of choice. Impulse control was measured using commission error standardized scores from the Test of Variables of Attention (TOVA). Incarceration was obtained using self-reported lifetime history of incarceration in correctional facilities. Results Findings indicated that impulse control moderated the association between years of injection drug use and incarceration in correctional facilities adjusting for ethnicity, gender, estimated pre-morbid intelligence, and age of first injection use. Specifically, among individuals that were intact in impulse control, four or more years of injection drug use was associated with incarceration (AOR=4.97, 95% CI: 2.0212.23). This finding was not observed among individuals with impaired impulse control (AOR=0.57, 95% CI: 0.103.23). Furthermore, impulse control moderated the association between regular cocaine use and incarceration. Among individuals that had a history of cocaine use, individuals with low impulse control but not impaired were more likely to have reported time in a correctional facility (AOR=6.28, 95% CI: 1.6823.60). There was no association among individuals with impaired or intact impulse control. Conclusion Results highlight the importance of considering cognitive measures of impulse control in addressing negative outcomes associated with drug use. PMID:18082337

  18. Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions.

    PubMed

    Nefiodov, A V; Plunien, G; Soff, G

    2002-08-19

    The influence of nuclear polarization on the bound-electron g factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron g factor in highly charged ions. PMID:12190457

  19. Correction of measured Gamma-Knife output factors for angular dependence of diode detectors and PinPoint ionization chamber.

    PubMed

    Hršak, Hrvoje; Majer, Marija; Grego, Timor; Bibić, Juraj; Heinrich, Zdravko

    2014-12-01

    Dosimetry for Gamma-Knife requires detectors with high spatial resolution and minimal angular dependence of response. Angular dependence and end effect time for p-type silicon detectors (PTW Diode P and Diode E) and PTW PinPoint ionization chamber were measured with Gamma-Knife beams. Weighted angular dependence correction factors were calculated for each detector. The Gamma-Knife output factors were corrected for angular dependence and end effect time. For Gamma-Knife beams angle range of 84°-54°. Diode P shows considerable angular dependence of 9% and 8% for the 18 mm and 14, 8, 4 mm collimator, respectively. For Diode E this dependence is about 4% for all collimators. PinPoint ionization chamber shows angular dependence of less than 3% for 18, 14 and 8 mm helmet and 10% for 4 mm collimator due to volumetric averaging effect in a small photon beam. Corrected output factors for 14 mm helmet are in very good agreement (within ±0.3%) with published data and values recommended by vendor (Elekta AB, Stockholm, Sweden). For the 8 mm collimator diodes are still in good agreement with recommended values (within ±0.6%), while PinPoint gives 3% less value. For the 4 mm helmet Diodes P and E show over-response of 2.8% and 1.8%, respectively. For PinPoint chamber output factor of 4 mm collimator is 25% lower than Elekta value which is generally not consequence of angular dependence, but of volumetric averaging effect and lack of lateral electronic equilibrium. Diodes P and E represent good choice for Gamma-Knife dosimetry. PMID:25266988

  20. Geometrical factor correction in grazing incident x-ray fluorescence experiment

    SciTech Connect

    Li Wenbin; Zhu Jingtao; Ma Xiaoying; Li Haochuan; Wang Hongchang; Wang Zhanshan; Sawhney, Kawal J. S.

    2012-05-15

    The geometrical factor in the grazing incident x-ray fluorescence analysis is an important angle-dependent term, which can have a great effect on the measured data. In this paper, the effects of the geometrical factor on the florescence yield have been demonstrated. A formula is presented to estimate the geometrical factor, which includes the experimental parameters of the beam and setup. The validity of this formula is proven by the good agreement between the calculated fluorescence yields with the experimental results in grazing incident x-ray fluorescence analysis.

  1. A transient, Hex-Z nodal code corrected by discontinuity factors. Volume 1: The transient nodal code; Final report

    SciTech Connect

    Shatilla, Y.A.M.; Henry, A.F.

    1993-12-31

    This document constitutes Volume 1 of the Final Report of a three-year study supported by the special Research Grant Program for Nuclear Energy Research set up by the US Department of Energy. The original motivation for the work was to provide a fast and accurate computer program for the analysis of transients in heavy water or graphite-moderated reactors being considered as candidates for the New Production Reactor. Thus, part of the funding was by way of pass-through money from the Savannah River Laboratory. With this intent in mind, a three-dimensional (Hex-Z), general-energy-group transient, nodal code was created, programmed, and tested. In order to improve accuracy, correction terms, called {open_quotes}discontinuity factors,{close_quotes} were incorporated into the nodal equations. Ideal values of these factors force the nodal equations to provide node-integrated reaction rates and leakage rates across nodal surfaces that match exactly those edited from a more exact reference calculation. Since the exact reference solution is needed to compute the ideal discontinuity factors, the fact that they result in exact nodal equations would be of little practical interest were it not that approximate discontinuity factors, found at a greatly reduced cost, often yield very accurate results. For example, for light-water reactors, discontinuity factors found from two-dimensional, fine-mesh, multigroup transport solutions for two-dimensional cuts of a fuel assembly provide very accurate predictions of three-dimensional, full-core power distributions. The present document (volume 1) deals primarily with the specification, programming and testing of the three-dimensional, Hex-Z computer program. The program solves both the static (eigenvalue) and transient, general-energy-group, nodal equations corrected by user-supplied discontinuity factors.

  2. Partial correction of a severe molecular defect in hemophilia A, because of errors during expression of the factor VIII gene

    SciTech Connect

    Young, M.; Antonarakis, S.E.; Inaba, Hiroshi

    1997-03-01

    Although the molecular defect in patients in a Japanese family with mild to moderately severe hemophilia A was a deletion of a single nucleotide T within an A{sub 8}TA{sub 2} sequence of exon 14 of the factor VIII gene, the severity of the clinical phenotype did not correspond to that expected of a frameshift mutation. A small amount of functional factor VIII protein was detected in the patient`s plasma. Analysis of DNA and RNA molecules from normal and affected individuals and in vitro transcription/translation suggested a partial correction of the molecular defect, because of the following: (i) DNA replication/RNA transcription errors resulting in restoration of the reading frame and/or (ii) {open_quotes}ribosomal frameshifting{close_quotes} resulting in the production of normal factor VIII polypeptide and, thus, in a milder than expected hemophilia A. All of these mechanisms probably were promoted by the longer run of adenines, A{sub 10} instead of A{sub 8}TA{sub 2}, after the delT. Errors in the complex steps of gene expression therefore may partially correct a severe frameshift defect and ameliorate an expected severe phenotype. 36 refs., 6 figs.

  3. [Indicators of exchange of bile pigments under the action of ecopathogenic factors on the organism and correction with liposomes].

    PubMed

    Mel'nychuk, D O; Hryshchenko, V A; Vesel'sky?, S P

    2014-01-01

    High levels of anthropogenic impact on the environment requires a detailed study of the features of the influence of heavy metals and ionizing radiation on living organisms, and provides for the development and use of effective means of protecting the body from its negative influence. The purpose of the work was to study the characteristics of the exchange of bile pigments of rats under the action of ecopathogenic factors (ionizing radiation and cadmium) on the organism and the corrective properties of liposomes on the basis of milk phospholipids. An analysis of the chromatographic studies of bilirubin and derivatives (nonconjugated bilirubin, bilirubin sulfate, billirubin glucuronide, urobilin and stercobilin) in the whole blood, liver, jejunum contents and feces under the action on the animal organism of ecopathogenic factors (ionizing radiation and cadmium) indicate material violation of the exchange bile pigments that may be due to the destabilization of the structural and functional hot hepatocytes. Correction of the liposomal form of biologically active additive (BAA) FLP-MD is recommended; the latter is a mixture of phospholipids isolated from milk, with a mixture of unsaturated fatty acids (oleic, linoleic, linolenic) and antioxidants (alpha-tocopherol and retinol acetate). The additive components exhibit the reparative effect of the action in respect of the damaged membrane structures with simultaneous improving of cholepoietic and billiation liver function, and therefore contribute to the normalization of exchange og bile pigments in terms of action on the body ecopathogenic factors. PMID:25033562

  4. Gas turbine parameter corrections

    SciTech Connect

    Volponi, A.J.

    1999-10-01

    The various parameters appearing along an engine's gas path, such as flows, pressures, temperatures, speeds, etc., not only vary with power condition but also with the ambient conditions at the engine's inlet. Since a change in inlet temperature and/or pressure will contribute to an attendant change in a gas path parameter's value, it would be difficult to characterize the aero-thermodynamic relationships between gas turbine engine parameters, (even at a constant engine operating point) unless the ambient conditions are somehow accounted for. This is usually accomplished through the use of corrected engine parameters. Although, most of these corrections are well known by practitioners in the industry, knowledge of their origin does not appear to be as commonplace. The purpose of this paper is to fill that gap and furnish a summary of the commonly used corrections for the major gas path parameters that are used in performance analysis, diagnostics, and control design, and to offer a derivation of these corrections. The author suggests both an analytic approach as well as an empirical approach. The latter can be used to establish the correction for parameters not directly addressed in this paper, as well as to fine tune the correction factors when actual engine data is available.

  5. In Vivo Gene Therapy of Hemophilia B: Sustained Partial Correction in Factor IX-Deficient Dogs

    NASA Astrophysics Data System (ADS)

    Kay, Mark A.; Rothenberg, Steven; Landen, Charles N.; Bellinger, Dwight A.; Leland, Frances; Toman, Carol; Finegold, Milton; Thompson, Arthur R.; Read, M. S.; Brinkhous, Kenneth M.; Woo, Savio L. C.

    1993-10-01

    The liver represents a model organ for gene therapy. A method has been developed for hepatic gene transfer in vivo by the direct infusion of recombinant retroviral vectors into the portal vasculature, which results in the persistent expression of exogenous genes. To determine if these technologies are applicable for the treatment of hemophilia B patients, preclinical efficacy studies were done in a hemophilia B dog model. When the canine factor IX complementary DNA was transduced directly into the hepatocytes of affected dogs in vivo, the animals constitutively expressed low levels of canine factor IX for more than 5 months. Persistent expression of the clotting. factor resulted in reductions of whole blood clotting and partial thromboplastin times of the treated animals. Thus, long-term treatment of hemophilia B patients may be feasible by direct hepatic gene therapy in vivo.

  6. An Improvement on Horn's Parallel Analysis Methodology for Selecting the Correct Number of Factors to Retain.

    ERIC Educational Resources Information Center

    Glorfeld, Louis W.

    1995-01-01

    A modification of Horn's parallel analysis is introduced that is based on the Monte Carlo simulation of the null distributions of the eigenvalues generated from a population correlation identity matrix. This modification reduces the tendency of the parallel analysis procedure to overextract or to extract poorly defined factors. (SLD)

  7. Determination of the quenching correction factors for plastic scintillation detectors in therapeutic high-energy proton beams

    NASA Astrophysics Data System (ADS)

    Wang, L. L. W.; Perles, L. A.; Archambault, L.; Sahoo, N.; Mirkovic, D.; Beddar, S.

    2012-12-01

    Plastic scintillation detectors (PSDs) have many advantages over other detectors in small field dosimetry due to their high spatial resolution, excellent water equivalence and instantaneous readout. However, in proton beams, the PSDs undergo a quenching effect which makes the signal level reduced significantly when the detector is close to the Bragg peak where the linear energy transfer (LET) for protons is very high. This study measures the quenching correction factor (QCF) for a PSD in clinical passive-scattering proton beams and investigates the feasibility of using PSDs in depth-dose measurements in proton beams. A polystyrene-based PSD (BCF-12, ?0.5 mm 4 mm) was used to measure the depth-dose curves in a water phantom for monoenergetic unmodulated proton beams of nominal energies 100, 180 and 250 MeV. A Markus plane-parallel ion chamber was also used to get the dose distributions for the same proton beams. From these results, the QCF as a function of depth was derived for these proton beams. Next, the LET depth distributions for these proton beams were calculated by using the MCNPX Monte Carlo code, based on the experimentally validated nozzle models for these passive-scattering proton beams. Then the relationship between the QCF and the proton LET could be derived as an empirical formula. Finally, the obtained empirical formula was applied to the PSD measurements to get the corrected depth-dose curves and they were compared to the ion chamber measurements. A linear relationship between the QCF and LET, i.e. Birks' formula, was obtained for the proton beams studied. The result is in agreement with the literature. The PSD measurements after the quenching corrections agree with ion chamber measurements within 5%. PSDs are good dosimeters for proton beam measurement if the quenching effect is corrected appropriately.

  8. Nerve growth factor corrects developmental impairments of basal forebrain cholinergic neurons in the trisomy 16 mouse.

    PubMed Central

    Corsi, P; Coyle, J T

    1991-01-01

    The trisomy 16 (Ts16) mouse, which shares genetic and phenotypic homologies with Down syndrome, exhibits impaired development of the basal forebrain cholinergic system. Basal forebrains obtained from Ts16 and euploid littermate fetuses at 15 days of gestation were dissociated and cultured in completely defined medium, with cholinergic neurons identified by choline acetyltransferase (ChAT) immunoreactivity. The Ts16 cultures exhibited fewer ChAT-immunoreactive neurons, which were smaller and emitted shorter, smoother, and more simplified neurites than those from euploid littermates. Whereas the addition of beta-nerve growth factor (100 ng/ml) augmented the specific activity of ChAT and neuritic extension for both Ts16 and euploid cholinergic neurons, only Ts16 cultures exhibited an increase in the number and size of ChAT-immunoreactive neurons. Furthermore, Ts16 ChAT-immunoreactive neurites formed varicosities only in the presence of beta-nerve growth factor. Images PMID:2000385

  9. Assessment of ionization chamber correction factors in photon beams using a time saving strategy with PENELOPE code.

    PubMed

    Reis, C Q M; Nicolucci, P

    2016-02-01

    The purpose of this study was to investigate Monte Carlo-based perturbation and beam quality correction factors for ionization chambers in photon beams using a saving time strategy with PENELOPE code. Simulations for calculating absorbed doses to water using full spectra of photon beams impinging the whole water phantom and those using a phase-space file previously stored around the point of interest were performed and compared. The widely used NE2571 ionization chamber was modeled with PENELOPE using data from the literature in order to calculate absorbed doses to the air cavity of the chamber. Absorbed doses to water at reference depth were also calculated for providing the perturbation and beam quality correction factors for that chamber in high energy photon beams. Results obtained in this study show that simulations with phase-space files appropriately stored can be up to ten times shorter than using a full spectrum of photon beams in the input-file. Values of kQ and its components for the NE2571 ionization chamber showed good agreement with published values in the literature and are provided with typical statistical uncertainties of 0.2%. Comparisons to kQ values published in current dosimetry protocols such as the AAPM TG-51 and IAEA TRS-398 showed maximum percentage differences of 0.1% and 0.6% respectively. The proposed strategy presented a significant efficiency gain and can be applied for a variety of ionization chambers and clinical photon beams. PMID:26873785

  10. On the importance of high-frequency air-temperature fluctuations for spectroscopic corrections of open-path carbon dioxide flux measurements

    NASA Astrophysics Data System (ADS)

    Bogoev, Ivan; Helbig, Manuel; Sonnentag, Oliver

    2015-04-01

    A growing number of studies report systematic differences in CO2 flux estimates obtained with the two main types of gas analyzers: compared to eddy-covariance systems based on closed-path (CP) gas analyzers, systems with open-path (OP) gas analyzers systematically overestimate CO2 uptake during daytime periods with high positive sensible heat fluxes, while patterns for differences in nighttime CO2 exchange are less obvious. These biases have been shown to correlate with the sign and the magnitude of the sensible heat flux and to introduce large uncertainties when calculating annual CO2 budgets. In general, CP and OP gas analyzers commonly used to measure the CO2 density in the atmosphere operate on the principle of infrared light absorption approximated by Beer-Lambert's law. Non-dispersive interference-based optical filter elements are used to select spectral bands with strong attenuation of light transmission, characteristic to the gas of interest. The intensity of the light passing through the optical sensing path depends primarily on the amount of absorber gas in the measurement volume. Besides the density of the gas, barometric pressure and air temperature are additional factors affecting the strength and the half-width of the absorption lines. These so-called spectroscopic effects are accounted for by measuring barometric pressure and air temperature in the sensing path and scaling the light-intensity measurements before applying the calibration equation. This approach works well for CP gas analyzers with an intake tube that acts as a low-pass filter on fast air-temperature fluctuations. Low-frequency response temperature sensors in the measurement cell are therefore sufficient to account for spectroscopic temperature effects. In contrast, OP gas analyzers are exposed to high-frequency air-temperature fluctuations associated with the atmospheric surface-layer turbulent heat exchange. If not corrected adequately, these fast air-temperature variations can cause systematic errors in the CO2 density measurements. Under conditions of high positive or negative sensible heat flux, air-temperature fluctuations are correlated with fluctuations of the vertical wind component and can lead to significant biases in the CO2 flux estimates. This study demonstrates that sonically derived fast-response air temperature in the optical sensing path of an OP gas analyzer can replace the slow-response measurements from the temperature sensor as a scaling parameter in the calibration model to correct for these air temperature-induced spectroscopic effects. Our approach is evaluated by comparison between different OP and CP gas analyzer-based eddy-covariance systems in ecosystems with low CO2 uptake under a range of sensible heat flux regimes and varying meteorological parameters. We show that ignoring high-frequency spectroscopic effects can lead to false interpretations of net ecosystem CO2 exchange for specific site and environmental conditions.

  11. Novel, cyclic heat dissipation method for the correction of natural temperature gradients in sap flow measurements. Part 2. Laboratory validation.

    PubMed

    Reyes-Acosta, J Leonardo; Vandegehuchte, Maurits W; Steppe, Kathy; Lubczynski, Maciek W

    2012-07-01

    Sap flow measurements conducted with thermal dissipation probes (TDPs) are vulnerable to natural temperature gradient (NTG) bias. Few studies, however, attempted to explain the dynamics underlying the NTG formation and its influence on the sensors' signal. This study focused on understanding how the TDP signals are affected by negative and positive temperature influences from NTG and tested the novel cyclic heat dissipation (CHD) method to filter out the NTG bias. A series of three experiments were performed in which gravity-driven water flow was enforced on freshly cut stem segments of Fagus sylvatica L., while an artificial temperature gradient (ATG) was induced. The first experiment sought to confirm the incidence of the ATG on sensors. The second experiment established the mis-estimations caused by the biasing effect of the ATG on standard TDP measurements. The third experiment tested the accuracy of the CHD method to account for the ATG biasing effect, as compared with other cyclic correction methods. During experiments, sap flow measured by TDP was assessed against gravimetric measurements. The results show that negative and positive ATGs were comparable in pattern but substantially larger than field NTGs. Second, the ATG bias caused an overestimation of the standard TDP sap flux density of ?17 cm(3) cm(-2) h(-1) by 76%, and the sap flux density of ?2 cm(3) cm(-2) h(-1) by over 800%. Finally, the proposed CHD method successfully reduced the max. ATG bias to 25% at ?11 cm(3) cm(-2) h(-1) and to 40% at ?1 cm(3) cm(-2) h(-1). We concluded that: (i) the TDP method is susceptible to NTG especially at low flows; (ii) the CHD method successfully corrected the TDP signal and resulted in generally more accurate sap flux density estimates (mean absolute percentage error ranging between 11 and 21%) than standard constant power TDP method and other cyclic power methods; and (iii) the ATG enforcing system is a suitable way of re-creating NTG for future tests. PMID:22659459

  12. Malabsorption of hemoglobin iron in pernicious anemia: correction with intrinsic factorcontaining substances

    PubMed Central

    Waxman, Samuel; Pratt, Peter; Herbert, Victor

    1968-01-01

    Hemoglobin iron absorption in patients with treated prenicious anemia (PA) and concomitant iron deficiency was low compared to absorption in patients with iron deficiency alone. Crude and purified hog intrinsic factor (IF) concentrates doubled the absorption of hemoglobin iron in these patients as did normal (neutralized depepsinized) human gastric juice. Hemoglobin iron absorption was not significantly enhanced by PA gastric juice. Absorption of heme iron, like that of hemoglobin iron, was enhanced by normal neutralized depepsinized gastric juice. No enhancement of hemoglobin iron absorption by these substances was obtained in the normal or iron-deficient non-PA control subjects. Preincubation of the hog IF concentrate with antisera to IF significantly reduced the enhancement of hemoglobin iron absorption due to the concentrate. In vitro studies suggest that heme complexes with a substance present in IF-containing materials. Whether a gastric glycoprotein similar to IF serves as an intestinal transport factor for heme, similar to transport of vitamin B12, or whether normal gastric juice acts by another mechanism cannot be determined at this time. Images PMID:5666112

  13. Deconvolution and chromatic aberration corrections in quantifying colocalization of a transcription factor in three-dimensional cellular space.

    PubMed

    Abraham, Thomas; Allan, Sarah E; Levings, Megan K

    2010-08-01

    In the realm of multi-dimensional confocal microscopy, colocalization analysis of fluorescent emission signals has proven to be an invaluable tool for detecting molecular interactions between biological macromolecules at the subcellular level. We show here that image processing operations such as the deconvolution and chromatic corrections play a crucial role in the accurate determination of colocalization between biological macromolecules particularly when the fluorescent signals are faint, and when the fluorescent signals are in the blue and red emission regions. The cellular system presented here describes quantification of an activated forkhead box P3 (FOXP3) transcription factor in three-dimensional (3D) cellular space. 293T cells transfected with a conditionally active form of FOXP3 were stained for anti-FOXP3 conjugated to a fluorescent red dye (Phycoerythrin), and counterstained for DNA (nucleus) with fluorescent blue dye (Hoechst). Due to the broad emission spectra of these dyes, the fluorescent signals were collected only from peak regions and were acquired sequentially. Since the PE signal was weak, a confocal pinhole size of two Airy size was used to collect the 3D image data sets. The raw images supplemented with the spectral data show the preferential association of activated FOXP3 molecules with the nucleus. However, the PE signals were found to be highly diffusive and colocalization quantification from these raw images was not possible. In order to deconvolve the 3D raw image data set, point spread functions (PSFs) of these emissions were measured. From the measured PSF, we found that chromatic shifts between the blue and red colors were quite considerable. Followed by the applications of both the axial and lateral chromatic corrections, colocalization analysis performed on the deconvolved-chromatic corrected-3D image data set showed that 98% of DNA molecules were associated with FOXP3 molecules, whereas only 66% of FOXP3 molecules were colocalized with DNA molecules. In conclusion, our studies clearly demonstrate the importance of PSF measurements, chromatic aberration corrections followed by deconvolution in the accurate determination of transcription factors in the 3D cellular space. The reported imaging and processing methods can be a practical guide for quantitative fluorescence imaging of similar cellular systems and can provide a basis for further development. PMID:20392647

  14. Single-Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications

    SciTech Connect

    Chinthavali, Madhu Sudhan; Onar, Omer C; Miller, John M; Tang, Lixin

    2013-01-01

    Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance. To understand the power flow through the system this paper presents a novel approach to the system model and the impact of different control parameters on the load power. The implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation is also discussed.

  15. Factor IX ectopically expressed in platelets can be stored in ?-granules and corrects the phenotype of hemophilia B mice

    PubMed Central

    Zhang, Guowei; Shi, Qizhen; Fahs, Scot A.; Kuether, Erin L.; Walsh, Christopher E.

    2010-01-01

    We developed 2bF9 transgenic mice in a hemophilia B mouse model with the expression of human factor IX (FIX) under control of the platelet-specific integrin ?IIb promoter, to determine whether ectopically expressing FIX in megakaryocytes can enable the storage of FIX in platelet ?-granules and corrects the murine hemophilia B phenotype. FIX was detected in the platelets and plasma of 2bF9 transgenic mice by both antigen and activity assays. Approximately 90% of total FIX in blood was stored in platelets, most of which is releasable on activation of platelets. Immunostaining demonstrated that FIX was expressed in platelets and megakaryocytes and stored in ?-granules. All 2bF9 transgenic mice survived tail clipping, suggesting that platelet-derived FIX normalizes hemostasis in the hemophilia B mouse model. This protection can be transferred by bone marrow transplantation or platelet transfusion. However, unlike our experience with platelet FVIII, the efficacy of platelet-derived FIX was limited in the presence of anti-FIX inhibitory antibodies. These results demonstrate that releasable FIX can be expressed and stored in platelet ?-granules and that platelet-derived FIX can correct the bleeding phenotype in hemophilia B mice. Our studies suggest that targeting FIX expression to platelets could be a new gene therapy strategy for hemophilia B. PMID:20445020

  16. Factor VIII delivered by haematopoietic stem cell-derived B cells corrects the phenotype of haemophilia A mice.

    PubMed

    Ramezani, Ali; Zweier-Renn, Lynnsey A; Hawley, Robert G

    2011-04-01

    The main impediments to clinical application of haematopoietic stem cell (HSC) gene therapy for treatment of haemophilia A are the bone marrow transplant-related risks and the potential for insertional mutagenesis caused by retroviral vectors. To circumvent these limitations, we have adapted a non-myeloablative conditioning regimen and directed factor VIII (FVIII) protein synthesis to B lineage cells using an insulated lentiviral vector containing an immunoglobulin heavy chain enhancer-promoter. Transplantation of lentiviral vector-modified HSCs resulted in therapeutic levels of FVIII in the circulation of all transplanted mice for the duration of the study (six months). Immunostaining of spleen cells showed that the majority of FVIII was synthesised by B220+ B cells and CD138+ plasma cells. Subsequent challenge with recombinant FVIII elicited at most a minor anti-FVIII antibody response, demonstrating induction of immune hyporesponsiveness. All transplant recipients exhibited clot formation and survived tail clipping, indicating correction of their haemophilic phenotype. Therapeutic levels of FVIII could be transferred to secondary recipients by bone marrow transplantation, confirming gene transfer into long-term repopulating HSCs. Moreover, short-term therapeutic FVIII levels could also be achieved in secondary recipients by adoptive transfer of HSC-derived splenic B cells. Our findings support pursuit of B cell-directed protein delivery as a potential clinical approach to treat haemophilia A and other disorders correctable by systemically distributed proteins. PMID:21264447

  17. Correction of Hypertension by Normalization of Endothelial Levels of Fibroblast Growth Factor and Nitric Oxide Synthase in Spontaneously Hypertensive Rats

    NASA Astrophysics Data System (ADS)

    Cuevas, Pedro; Garcia-Calvo, Margarita; Carceller, Fernando; Reimers, Diana; Zazo, Mercedes; Cuevas, Begona; Munoz-Willery, Isabel; Martinez-Coso, Victoria; Lamas, Santiago; Gimenez-Gallego, Guillermo

    1996-10-01

    Acidic and basic fibroblast growth factors (FGFs) share a wide range of diverse biological activities. To date, low levels of FGF have not been correlated with a pathophysiologic state. We report that blood vessels of spontaneously hypertensive rats are shown to be associated with a marked decrement in endothelial basic FGF content. This decrement correlates both with hypertension and with a decrease in the endothelial content of nitric oxide synthase. restoration of FGF to physiological levels in the vascular wall, either by systemic administration or by in vivo gene transfer, significantly augmented the number of endothelial cells with positive immunostaining for nitric oxide synthase, corrected hypertension, and ameliorated endothelial-dependent responses to vasoconstrictors. These results suggest an important role for FGFs in blood pressure homeostasis and open new avenues for the understanding of the etiology and treatment of hypertension.

  18. SU-F-BRE-01: A Rapid Method to Determine An Upper Limit On a Radiation Detector's Correction Factor During the QA of IMRT Plans

    SciTech Connect

    Kamio, Y; Bouchard, H

    2014-06-15

    Purpose: Discrepancies in the verification of the absorbed dose to water from an IMRT plan using a radiation dosimeter can be wither caused by 1) detector specific nonstandard field correction factors as described by the formalism of Alfonso et al. 2) inaccurate delivery of the DQA plan. The aim of this work is to develop a simple/fast method to determine an upper limit on the contribution of composite field correction factors to these discrepancies. Methods: Indices that characterize the non-flatness of the symmetrised collapsed delivery (VSC) of IMRT fields over detector-specific regions of interest were shown to be correlated with IMRT field correction factors. The indices introduced are the uniformity index (UI) and the mean fluctuation index (MF). Each one of these correlation plots have 10 000 fields generated with a stochastic model. A total of eight radiation detectors were investigated in the radial orientation. An upper bound on the correction factors was evaluated by fitting values of high correction factors for a given index value. Results: These fitted curves can be used to compare the performance of radiation dosimeters in composite IMRT fields. Highly water-equivalent dosimeters like the scintillating detector (Exradin W1) and a generic alanine detector have been found to have corrections under 1% over a broad range of field modulations (0 0.12 for MF and 0 0.5 for UI). Other detectors have been shown to have corrections of a few percent over this range. Finally, a full Monte Carlo simulations of 18 clinical and nonclinical IMRT field showed good agreement with the fitted curve for the A12 ionization chamber. Conclusion: This work proposes a rapid method to evaluate an upper bound on the contribution of correction factors to discrepancies found in the verification of DQA plans.

  19. Basic factors controlling pest in high temperature systems

    NASA Technical Reports Server (NTRS)

    Berkowitz-Mattuck, J.; Rossetti, M.

    1971-01-01

    The catastrophic disintegration in air at intermediate temperatures of refractory materials which are very resistant to oxidation at high temperatures is known as pest. A study was undertaken to determine whether the mechanism proposed for pest failure in silicides might also be responsible for pest failure in NbAl3. The aim was to correlate oxidation kinetics in the range where disintegration of NbAl3 is observed with delayed failure data obtained under similar conditions. Studies were also undertaken to develop some understanding of deformation mechanisms in both silicides and aluminides.

  20. A monomeric von Willebrand factor fragment, Leu-504--Lys-728, inhibits von Willebrand factor interaction with glycoprotein Ib-IX [corrected

    PubMed Central

    Gralnick, H R; Williams, S; McKeown, L; Kramer, W; Krutzsch, H; Gorecki, M; Pinet, A; Garfinkel, L I

    1992-01-01

    von Willebrand factor interaction with glycoprotein Ib alpha (GPIb alpha) plays a critical role in the initial phase of platelet adhesion at high shear rates, and it may also play a role in platelet thrombus formation in partially occluded arteries. Previous studies have indicated that two peptides, Cys-474--Pro-488 (peptide 153) and Ser-692--Pro-708 (peptide 154), inhibit von Willebrand factor--GPIb alpha interaction. We have expressed a recombinant fragment of von Willebrand factor, Leu-504--Lys-728 [corrected], with a single intrachain disulfide bond linking residues Cys-509--Cys-695 and examined its ability to inhibit von Willebrand factor--GPIb alpha interactions and platelet adhesion at high shear forces. This recombinant fragment, named VCL, inhibits ristocetin-induced, botrocetin-induced, and asialo-von Willebrand factor-induced platelet aggregation and binding to platelets at an IC50 = 0.011-0.260 microM, significantly lower than the IC50 of peptide 153 or 154, IC50 = 86-700 microM. Peptides 153 and 154 did not result in any inhibition of platelet adhesion (IC50 greater than 500 microM). In contrast, VCL inhibited 50% of platelet adhesion at 0.94 microM and at 7.6 microM inhibited greater than 80% of platelet adhesion to human umbilical artery subendothelium at high shear forces. VCL inhibited the contact and spreading of platelets and also caused a marked decrease in thrombus formation. These studies indicate that VCL may be an effective antithrombotic agent in preventing arterial thrombus formation in areas of high shear force. PMID:1518808

  1. Correction of the equilibrium temperature caused by slight evaporation of water in protein crystal growth cells during long-term space experiments at International Space Station

    NASA Astrophysics Data System (ADS)

    Fujiwara, Takahisa; Suzuki, Yoshihisa; Yoshizaki, Izumi; Tsukamoto, Katsuo; Murayama, Kenta; Fukuyama, Seijiro; Hosokawa, Kouhei; Oshi, Kentaro; Ito, Daisuke; Yamazaki, Tomoya; Tachibana, Masaru; Miura, Hitoshi

    2015-08-01

    The normal growth rates of the {110} faces of tetragonal hen egg-white lysozyme crystals, R, were measured as a function of the supersaturation σ parameter using a reflection type interferometer under μG at the International Space Station (NanoStep Project). Since water slightly evaporated from in situ observation cells during a long-term space station experiment for several months, equilibrium temperature Te changed, and the actual σ, however, significantly increased mainly due to the increase in salt concentration Cs. To correct σ, the actual Cs and protein concentration Cp, which correctly represent the measured Te value in space, were first calculated. Second, a new solubility curve with the corrected Cs was plotted. Finally, the revised σ was obtained from the new solubility curve. This correction method successfully revealed that the 2.8% water was evaporated from the solution, leading to 2.8% increase in the Cs and Cp of the solution.

  2. PHYSICOCHEMICAL FACTORS AFFECTING TOXICITY IN FRESHWATER: HARDNESS, PH, AND TEMPERATURE

    EPA Science Inventory

    A search of the literature for effects of hardness, pH, or temperature on the toxicity of chemicals to freshwater organisms suggested that the amount of reliable and useful data is limited. uch of the disparity among results reported in the literature was caused by improperly des...

  3. Correction of murine hemophilia A and immunological differences of factor VIII variants delivered by helper-dependent adenoviral vectors.

    PubMed

    Cerullo, Vincenzo; Seiler, Michael P; Mane, Viraj; Cela, Racel; Clarke, Christian; Kaufman, Randal J; Pipe, Steven W; Lee, Brendan

    2007-12-01

    Bioengineering of the factor VIII (FVIII) molecule has led to the production of variants that overcome poor secretion and/or rapid inactivation. We tested six modified FVIII variants for in vivo efficacy by expressing them from helper-dependent adenoviral (HD-Ad) vectors. We constructed a wild-type (WT) variant, a B-domain-deleted (BDD) variant, a point mutant for improved secretion (F309S), a variant with a partial B-domain deletion for improved secretion (N6), a combination of the point mutant and partial BDD variant (F309N6), and an inactivation-resistant (IR8) FVIII variant. All the constructs expressed functional protein after injection of high-dose HD-Ad. Activity ranged from 20 to 50% with WT, to approximately 100% with the N6 and F309N6 variants. Interestingly, mice treated with N6 showed long-term FVIII activity and phenotypic correction for up to 74 weeks, with low anti-FVIII antibody titer. Importantly, the N6 variant was therapeutically efficacious even after a 50% reduction of viral dose, thereby indicating that transgene modification itself can improve the dose efficacy of HD-Ad. This finding is significant, because dose efficacy is a key factor in clinical application. In summary, bioengineering of the FVIII molecule may be an effective approach to improving the safety, immunogenicity, and efficacy of HD-Ad gene therapy in hemophilia A (HA). PMID:17848960

  4. The effects and correction of the geometric factor for the POES/MEPED electron flux instrument using a multisatellite comparison

    NASA Astrophysics Data System (ADS)

    Whittaker, Ian C.; Rodger, Craig J.; Clilverd, Mark A.; Sauvaud, Jean-Andr

    2014-08-01

    Measurements from the Polar-Orbiting Environmental Satellite (POES) Medium Energy Proton and Electron Detector (MEPED) instrument are widely used in studies into radiation belt dynamics and atmospheric coupling. However, this instrument has been shown to have a complex energy-dependent response to incident particle fluxes, with the additional possibility of low-energy protons contaminating the electron fluxes. We test the recent Monte Carlo theoretical simulation of the instrument by comparing the responses against observations from an independent experimental data set. Our study examines the reported geometric factors for the MEPED electron flux instrument against the high-energy resolution Instrument for Detecting Particles (IDPs) on the Detection of Electromagnetic Emissions Transmitted from Earthquake Regions satellite when they are located at similar locations and times, thereby viewing the same quasi-trapped population of electrons. We find that the new Monte Carlo-produced geometric factors accurately describe the response of the POES MEPED instrument. We go on to develop a set of equations such that integral electron fluxes of a higher accuracy are obtained from the existing MEPED observations. These new MEPED integral fluxes correlated very well with those from the IDP instrument (>99.9% confidence level). As part of this study we have also tested a commonly used algorithm for removing proton contamination from MEPED instrument observations. We show that the algorithm is effective, providing confirmation that previous work using this correction method is valid.

  5. Long-term phenotypic correction in factor IX knockout mice by using ?C31 integrase-mediated gene therapy.

    PubMed

    Keravala, A; Chavez, C L; Hu, G; Woodard, L E; Monahan, P E; Calos, M P

    2011-08-01

    Hemophilia B, a hereditary bleeding disorder caused by a deficiency of coagulation factor IX (FIX), is an excellent candidate for gene therapy. However, to date, success in hemophilia gene therapy clinical trials has been limited due to failure to achieve or sustain therapeutic levels of factor expression. The ?C31 integrase system efficiently integrates plasmid DNA carrying a transgene and an attB site into a limited number of endogenous pseudo attP sites in mammalian genomes, leading to robust, sustained transgene expression. A strategy utilizing plasmid DNA integrated with ?C31 integrase may offer a facile and safe alternative for sustained human FIX (hFIX) expression. Hydrodynamic tail vein injection was used for delivery of plasmids encoding ?C31 integrase and hFIX to the liver of FIX knockout mice. We demonstrated prolonged therapeutic levels of hFIX in this knockout mouse model of hemophilia B over a 6-month time course when ?C31 integrase was used. Additionally, we observed sustained FIX activity in plasma and phenotypic correction of bleeding after tail clip in ?C31-treated mice. In the livers that received integrase, we also demonstrated prolonged hFIX expression in hepatocytes by immunohistochemistry and documented sequence-specific genomic integration of the hFIX plasmid. These studies suggest the possibility that a similar approach in large animals and humans could lead to a simple and successful gene therapy for hemophilia. PMID:21412285

  6. Quantitative measurement of temperature by proton resonance frequency shift at low field: a general method to correct non-linear spatial and temporal phase deformations

    NASA Astrophysics Data System (ADS)

    Grimault, S.; Lucas, T.; Quellec, S.; Mariette, F.

    2004-09-01

    MRI thermometry methods are usually based on the temperature dependence of the proton resonance frequency. Unfortunately, these methods are very sensitive to the phase drift induced by the instability of the scanner which prevents any temperature mapping over long periods of time. A general method based on 3D spatial modelling of the phase drift as a function of time is presented. The MRI temperature measurements were validated on gel samples with uniform and constant temperature and with a linear temperature gradient. In the case of uniform temperature conditions, correction of the phase drift proved to be essential when long periods of acquisition were required, as bias could reach values of up to 200 C in its absence. The temperature uncertainty measured by MRI was 1.2 C in average over 290 min. This accuracy is coherent with the requirements for food applications especially when thermocouples are useless.

  7. Temperature Data Assimilation with Salinity Corrections: Validation for the NSIPP Ocean Data Assimilation System in the Tropical Pacific Ocean, 1993-1998

    NASA Technical Reports Server (NTRS)

    Troccoli, Alberto; Rienecker, Michele M.; Keppenne, Christian L.; Johnson, Gregory C.

    2003-01-01

    The NASA Seasonal-to-Interannual Prediction Project (NSIPP) has developed an Ocean data assimilation system to initialize the quasi-isopycnal ocean model used in our experimental coupled-model forecast system. Initial tests of the system have focused on the assimilation of temperature profiles in an optimal interpolation framework. It is now recognized that correction of temperature only often introduces spurious water masses. The resulting density distribution can be statically unstable and also have a detrimental impact on the velocity distribution. Several simple schemes have been developed to try to correct these deficiencies. Here the salinity field is corrected by using a scheme which assumes that the temperature-salinity relationship of the model background is preserved during the assimilation. The scheme was first introduced for a zlevel model by Troccoli and Haines (1999). A large set of subsurface observations of salinity and temperature is used to cross-validate two data assimilation experiments run for the 6-year period 1993-1998. In these two experiments only subsurface temperature observations are used, but in one case the salinity field is also updated whenever temperature observations are available.

  8. Correction of temperature and bulk electrical conductivity effects on soil water content measurements using ECH2O EC-5, TE and 5TE sensors

    NASA Astrophysics Data System (ADS)

    Rosenbaum, Ulrike; Huisman, Sander; Vrba, Jan; Vereecken, Harry; Bogena, Heye

    2010-05-01

    For a monitoring of dynamic spatiotemporal soil moisture patterns at the catchment scale, automated and continuously measuring systems that provide spatial coverage and high temporal resolution are needed. Promising techniques like wireless sensor networks (e.g. SoilNet) have to integrate low-cost electromagnetic soil water content sensors [1], [2]. However, the measurement accuracy of such sensors is often deteriorated by effects of temperature and soil bulk electrical conductivity. The objective of this study is to derive and validate correction functions for such temperature and electrical conductivity effects for the ECH2O EC-5, TE and 5TE sensors. We used dielectric liquids with known dielectric properties for two different laboratory experiments. In the first experiment, the temperature of eight reference liquids with permittivity ranging from 7 to 42 was varied from 5 to 40C. All sensor types showed an underestimation of permittivity for low temperatures and an overestimation for high temperatures. In the second experiment, the conductivity of the reference liquids was increased by adding NaCl. The highest deviations occurred for high permittivity and electrical conductivity between ~0.8 and 1.5 dS/m (underestimation from 8 to 16 permittivity units depending on sensor type). For higher electrical conductivity (2.5 dS/m), the permittivity was overestimated (10 permittivity units for the EC-5 and 7 for the 5TE sensor). Based on these measurements on reference liquids, we derived empirical correction functions that are able to correct thermal and conductivity effects on measured sensor response. These correction functions were validated using three soil samples (coarse sand, silty clay loam and bentonite). For the temperature correction function, the results corresponded better with theoretical predictions after correction for temperature effects on the sensor circuitry. It was also shown that the application of the conductivity correction functions improved the accuracy of the soil water content predictions considerably. References: [1] Bogena, H.R., J.A. Huisman, C. Oberdrster, H. Vereecken (2007): Evaluation of a low-cost soil water content sensor for wireless network applications. Journal of Hydrology: 344, 32- 42. [2] Rosenbaum, U., Huisman, J.A., Weuthen, A., Vereecken, H. and Bogena, H.R. (2010): Quantification of sensor-to-sensor variability of the ECH2O EC-5, TE and 5TE sensors in dielectric liquids. Accepted for publication in VZJ (09/2009).

  9. Mutual correction of faulty PCNA subunits in temperature-sensitive lethal mus209 mutants of Drosophila melanogaster.

    PubMed Central

    Henderson, D S; Wiegand, U K; Norman, D G; Glover, D M

    2000-01-01

    Proliferating cell nuclear antigen (PCNA) functions in DNA replication as a processivity factor for polymerases delta and epsilon, and in multiple DNA repair processes. We describe two temperature-sensitive lethal alleles (mus209(B1) and mus209(2735)) of the Drosophila PCNA gene that, at temperatures permissive for growth, result in hypersensitivity to DNA-damaging agents, suppression of position-effect variegation, and female sterility in which ovaries are underdeveloped and do not produce eggs. We show by mosaic analysis that the sterility of mus209(B1) is partly due to a failure of germ-line cells to proliferate. Strikingly, mus209(B1) and mus209(2735) interact to restore partial fertility to heteroallelic females, revealing additional roles for PCNA in ovarian development, meiotic recombination, and embryogenesis. We further show that, although mus209(B1) and mus209(2735) homozygotes are each defective in repair of transposase-induced DNA double-strand breaks in somatic cells, this defect is substantially reversed in the heteroallelic mutant genotype. These novel mutations map to adjacent sites on the three-dimensional structure of PCNA, which was unexpected in the context of this observed interallelic complementation. These mutations, as well as four others we describe, reveal new relationships between the structure and function of PCNA. PMID:10747065

  10. Factors Controlling Elevated Temperature Strength Degradation of Silicon Carbide Composites

    NASA Technical Reports Server (NTRS)

    2005-01-01

    For 5 years, the cooperative agreement NCC3-763 has focused on the development and understanding of Sic-based composites. Most of the work was performed in the area of SiC fiber-reinforced composites for UEET and NGLT and in collaboration with Goodrich Corporation under a partially reimbursable Space Act Agreement. A smaller amount of work was performed on C fiber-reinforced SiC matrix composites for NGLT. Major accomplishments during this agreement included: Improvements to the interphase used in melt-infiltrated (MI) SiC/SiC composites which increases the life under stressed-oxidation at intermediate temperatures referred to as "outside-debonding". This concept is currently in the patent process and received a Space Act Award. Mechanistic-based models of intermediate temperature degradation for MI SiC/SiC Quantification and relatively robust relationships for matrix crack evolution under stress in SiC/SiC composites which serve as the basis for stress-strain and elevated temperature life models The furthering of acoustic emission as a useful tool in composite damage evolution and the extension of the technique to other composite systems Development of hybrid C-SiC fiber-reinforced SiC matrix composites Numerous presentations at conferences, industry partners, and government centers and publications in recognized proceedings and journals. Other recognition of the author's accomplishments by NASA with a TGIR award (2004), NASA's Medal for Public Service (2004), and The American Ceramic Society s Richard M. Fulrath Award (2005). The following will briefly describe the work of the past five years in the three areas of interest: SiC/SiC composite development, mechanistic understanding and modeling of SiC/SiC composites, and environmental durability of C/SiC composites. More detail can be found in the publications cited at the end of this report.

  11. Anomalous Temperature Dependence of the Quality Factor in a Superconducting Coplanar Waveguide Resonator

    NASA Astrophysics Data System (ADS)

    Zhou, Pin-Jia; Wang, Yi-Wen; Wei, Lian-Fu

    2014-06-01

    We present the measurements of the temperature dependence of the internal quality factor (Qi) of a microwave resonator, well below the superconducting transition temperature. The device is a quarter-wavelength niobium (Tc = 9.2 K) coplanar waveguide resonator. The measured |S21| parameter shows typically the skewed Lorentzian distributions, from which the fitted quality factor monotonically decreases with the temperature increasing from 30 mK to 900 mK. It is observed that for the lower temperature range (i.e., at T < 700 mK) the temperature dependence of the fitted Qi deviates significantly from the predictions of the usual MattisBardeen theory. The measured 3 dB internal quality factor Q'i also verifies such an anomalous temperature dependence. Physically, this phenomenon could be attributed dominantly to the effects of the two-level systems in the device, rather than the usual temperature-dependent complex conductance.

  12. One-Electron Energy Levels Based on the Temperature-Dependent Thomas-Fermi-Dirac-Weizscker Model of Atoms with a Correlation Correction

    NASA Astrophysics Data System (ADS)

    Yonei, Katsumi

    1988-05-01

    Using an effective potential determined from the temperature-dependent Thomas-Fermi-Dirac-Weizscker theory with a correlation correction, the bound state one-electron energies of atoms embedded in a neutral medium are calculated. In evaluating the energy eigenvalues, use is made of the WKB approximation. As an example to illustrate the temperature and the compression effects on the one-electron energies, the calculated results for Fe at temperatures ranging from 0 to 1000 eV under fixed compressions ?/?0{=}1, 10 and 100 are presented. The results are in good agreement with available data from SCF methods.

  13. Field calibration of multi-scattering correction factor for aethalometer aerosol absorption coefficient during CAPMEX Campaign, 2008

    NASA Astrophysics Data System (ADS)

    Kim, J. H.; Kim, S. W.; Yoon, S. C.; Park, R.; Ogren, J. A.

    2014-12-01

    Filter-based instrument, such as aethalometer, is being widely used to measure equivalent black carbon(EBC) mass concentration and aerosol absorption coefficient(AAC). However, many other previous studies have poited that AAC and its aerosol absorption angstrom exponent(AAE) are strongly affected by the multi-scattering correction factor(C) when we retrieve AAC from aethalometer EBC mass concentration measurement(Weingartner et al., 2003; Arnott et al., 2005; Schmid et al., 2006; Coen et al., 2010). We determined the C value using the method given in Weingartner et al. (2003) by comparing 7-wavelngth aethalometer (AE-31, Magee sci.) to 3-wavelength Photo-Acoustic Soot Spectrometer (PASS-3, DMT) at Gosan climate observatory, Korea(GCO) during Cheju ABC plume-asian monsoon experiment(CAPMEX) campaign(August and September, 2008). In this study, C was estimated to be 4.04 ± 1.68 at 532 nm and AAC retrieved with this value was decreased as approximately 100% as than that retrieved with soot case value from Weingartner et al (2003). We compared the AAC determined from aethalomter measurements to that from collocated Continuous Light Absorption Photometer (CLAP) measurements from January 2012 to December 2013 at GCO and found good agreement in both AAC and AAE. This result suggests the determination of site-specific C is crucially needed when we calculate AAC from aethalometer measurements.

  14. SU-E-T-101: Determination and Comparison of Correction Factors Obtained for TLDs in Small Field Lung Heterogenous Phantom Using Acuros XB and EGSnrc

    SciTech Connect

    Soh, R; Lee, J; Harianto, F

    2014-06-01

    Purpose: To determine and compare the correction factors obtained for TLDs in 2 × 2cm{sup 2} small field in lung heterogenous phantom using Acuros XB (AXB) and EGSnrc. Methods: This study will simulate the correction factors due to the perturbation of TLD-100 chips (Harshaw/Thermoscientific, 3 × 3 × 0.9mm{sup 3}, 2.64g/cm{sup 3}) in small field lung medium for Stereotactic Body Radiation Therapy (SBRT). A physical lung phantom was simulated by a 14cm thick composite cork phantom (0.27g/cm{sup 3}, HU:-743 ± 11) sandwiched between 4cm thick Plastic Water (CIRS,Norfolk). Composite cork has been shown to be a good lung substitute material for dosimetric studies. 6MV photon beam from Varian Clinac iX (Varian Medical Systems, Palo Alto, CA) with field size 2 × 2cm{sup 2} was simulated. Depth dose profiles were obtained from the Eclipse treatment planning system Acuros XB (AXB) and independently from DOSxyznrc, EGSnrc. Correction factors was calculated by the ratio of unperturbed to perturbed dose. Since AXB has limitations in simulating actual material compositions, EGSnrc will also simulate the AXB-based material composition for comparison to the actual lung phantom. Results: TLD-100, with its finite size and relatively high density, causes significant perturbation in 2 × 2cm{sup 2} small field in a low lung density phantom. Correction factors calculated by both EGSnrc and AXB was found to be as low as 0.9. It is expected that the correction factor obtained by EGSnrc wlll be more accurate as it is able to simulate the actual phantom material compositions. AXB have a limited material library, therefore it only approximates the composition of TLD, Composite cork and Plastic water, contributing to uncertainties in TLD correction factors. Conclusion: It is expected that the correction factors obtained by EGSnrc will be more accurate. Studies will be done to investigate the correction factors for higher energies where perturbation may be more pronounced.

  15. Dependence of reliability of GaN LEDs on their junction temperatures and ideal factors

    NASA Astrophysics Data System (ADS)

    Shen, Haiping; Zhou, Xiaoli; Zhang, Wanlu; Liu, Muqing

    2010-12-01

    The relationship between the reliability of GaN LEDs and their junction temperatures and ideal factors is investigated. 20 groups of both blue and white GaN LEDs are tested. Their ideal factors and junction temperatures under 700mA operating current are measured. The measurement methods are introduced. After the measurement, 700mA high current accelerated life test is carried out on the LEDs. Analysis results show that the reliability of the LEDs is strongly dependent on their junction temperatures and ideal factors. For most of the unreliable LEDs with their 50% ALT life less than 400 hours, their ideal factors are higher than 10, or the junction temperatures of the blue LEDs under 700mA are higher than 130°C, and the junction temperatures of the white LEDs under 700mA are higher than 120°C.

  16. Period-doubling bifurcation in two-stage power factor correction converters using the method of incremental harmonic balance and Floquet theory

    NASA Astrophysics Data System (ADS)

    Wang, Fa-Qiang; Zhang, Hao; Ma, Xi-Kui

    2012-02-01

    In this paper, period-doubling bifurcation in a two-stage power factor correction converter is analyzed by using the method of incremental harmonic balance (IHB) and Floquet theory. A two-stage power factor correction converter typically employs a cascade configuration of a pre-regulator boost power factor correction converter with average current mode control to achieve a near unity power factor and a tightly regulated post-regulator DCDC Buck converter with voltage feedback control to regulate the output voltage. Based on the assumption that the tightly regulated post-regulator DCDC Buck converter is represented as a constant power sink and some other assumptions, the simplified model of the two-stage power factor correction converter is derived and its approximate periodic solution is calculated by the method of IHB. And then, the stability of the system is investigated by using Floquet theory and the stable boundaries are presented on the selected parameter spaces. Finally, some experimental results are given to confirm the effectiveness of the theoretical analysis.

  17. Correction factors kE and kQ for LiF-TLDs for dosimetry in megavoltage electron and photon beams.

    TOXLINE Toxicology Bibliographic Information

    Bruggmoser G; Saum R; Saum F; Gainey M; Pychlau C; Kapsch RP; Zink K

    2015-06-01

    For the determination of absorbed dose to water D,using thermolumeniscence (TL) probes in a beam different from that used for calibration, correction factors for radiation type and radiation quality kE and kQ are needed. Values for kE and kQ for two different shapes of LiF probes (rods and disks) were obtained for high-energy photon and electron beams. The relation between the absorbed dose to the medium (water) D, measured by ion-chambers according to DIN 6800-2, 2008 and TL-probes having a (60)Co-calibration factor, leads for each shape and each batch of LiF probes to correction factors for radiation type and radiation quality kE and kQ.. The influence of the shape on the correction factor of the probes amounts in our experiment up to 2%. Therefore, it is recommended that the correction factors kE and kQ for rods and disks should be checked for each batch of LiF-detectors.

  18. Low temperature coefficient of resistance and high gage factor in beryllium-doped silicon

    NASA Technical Reports Server (NTRS)

    Robertson, J. B.; Littlejohn, M. A.

    1974-01-01

    The gage factor and resistivity of p-type silicon doped with beryllium was studied as a function of temperature, crystal orientation, and beryllium doping concentration. It was shown that the temperature coefficient of resistance can be varied and reduced to zero near room temperature by varying the beryllium doping level. Similarly, the magnitude of the piezoresistance gage factor for beryllium-doped silicon is slightly larger than for silicon doped with a shallow acceptor impurity such as boron, whereas the temperature coefficient of piezoresistance is about the same for material containing these two dopants. These results are discussed in terms of a model for the piezoresistance of compensated p-type silicon.

  19. Constraints on hard spectator scattering and annihilation corrections in Bu,d → PV decays within QCD factorization

    NASA Astrophysics Data System (ADS)

    Sun, Junfeng; Chang, Qin; Hu, Xiaohui; Yang, Yueling

    2015-04-01

    In this paper, we investigate the contributions of hard spectator scattering and annihilation in B → PV decays within the QCD factorization framework. With available experimental data on B → πK* , ρK , πρ and Kϕ decays, comprehensive χ2 analyses of the parameters XA,Hi,f (ρA,Hi,f, ϕA,Hi,f) are performed, where XAf (XAi) and XH are used to parameterize the endpoint divergences of the (non)factorizable annihilation and hard spectator scattering amplitudes, respectively. Based on χ2 analyses, it is observed that (1) The topology-dependent parameterization scheme is feasible for B → PV decays; (2) At the current accuracy of experimental measurements and theoretical evaluations, XH = XAi is allowed by B → PV decays, but XH ≠ XAf at 68% C.L.; (3) With the simplification XH = XAi, parameters XAf and XAi should be treated individually. The above-described findings are very similar to those obtained from B → PP decays. Numerically, for B → PV decays, we obtain (ρA,Hi ,ϕA,Hi [ ° ]) = (2.87-1.95+0.66 , -145-21+14) and (ρAf, ϕ A f [ ° ]) = (0.91-0.13+0.12 , -37-9+10) at 68% C.L. With the best-fit values, most of the theoretical results are in good agreement with the experimental data within errors. However, significant corrections to the color-suppressed tree amplitude α2 related to a large ρH result in the wrong sign for ACPdir (B- →π0K*-) compared with the most recent BABAR data, which presents a new obstacle in solving "ππ" and "πK" puzzles through α2. A crosscheck with measurements at Belle (or Belle II) and LHCb, which offer higher precision, is urgently expected to confirm or refute such possible mismatch.

  20. The NLO contributions to the scalar pion form factors and the O (αs2) annihilation corrections to the B → ππ decays

    NASA Astrophysics Data System (ADS)

    Cheng, Shan; Zhang, Ya-Lan; Xiao, Zhen-Jun

    2015-07-01

    In this paper, by employing the kT factorization theorem, we made the first calculation for the space-like scalar pion form factor Q2 F (Q2) at the leading order (LO) and the next-to-leading order (NLO) level, and then found the time-like scalar pion form factor Fa,I‧ (1) by analytic continuation from the space-like one. From the analytical evaluations and the numerical results, we found the following points: (a) the NLO correction to the space-like scalar pion form factor has an opposite sign with the LO one but is very small in magnitude, can produce at most 10% decrease to the LO result in the considered Q2 region; (b) the NLO time-like scalar pion form factor Fa,I‧ (1) describes the O (αs2) contribution to the factorizable annihilation diagrams of the considered B → ππ decays, i.e. the NLO annihilation correction; (c) the NLO part of the form factor Fa,I‧ (1) is very small in size, and is almost independent of the variation of cutoff scale μ0, but this form factor has a large strong phase around - 55 ° and may play an important role in producing large CP violation for B → ππ decays; and (d) for B0 →π+π- and π0π0 decays, the newly known NLO annihilation correction can produce only a very small enhancement to their branching ratios, less than 3% in magnitude, and therefore we could not interpret the well-known ππ-puzzle by the inclusion of this NLO correction to the factorizable annihilation diagrams.

  1. High School 9th Grade Students' Understanding Level and Misconceptions about Temperature and Factors Affecting It

    ERIC Educational Resources Information Center

    Akbas, Yavuz

    2012-01-01

    The purpose of this study is to explore students' understanding levels and misconceptions about temperature and factors affecting it. The concept of the study was chosen from Geography National Curriculum. In this study, a questionnaire was developed after a pilot study with an aim to ascertain the students' understanding levels of temperature and…

  2. Short-term correction of factor VIII deficiency in a murine model of hemophilia A after delivery of adenovirus murine factor VIII in utero.

    PubMed

    Lipshutz, G S; Sarkar, R; Flebbe-Rehwaldt, L; Kazazian, H; Gaensler, K M

    1999-11-01

    Development of in utero gene transfer approaches may provide therapies for genetic disorders with perinatal morbidity. In hemophilia A, prenatal and postnatal bleeding may be catastrophic, and modest increments in factor VIII (FVIII) activity are therapeutic. We performed transuterine i.p. gene transfer at day 15 of gestation in a murine model of hemophilia A. Normal, carrier (X(H)X), and FVIII-deficient (X(H)Y and X(H)X(H)) fetuses injected with adenoviral vectors carrying luciferase or beta-galactosidase reporter genes showed high-level gene expression with 91% fetal survival. The live-born rates of normal and FVIII-deficient animals injected in utero with adenovirus murine FVIII (3.3 x 10(5) plaque-forming units) was 87%. FVIII activity in plasma was 50.7 +/- 10.5% of normal levels at day 2 of life, 7.2 +/- 2.2% by day 15 of life, and no longer detectable at day 21 of life in hemophilic animals. Injection of higher doses of murine FVIII adenovirus at embryonic day 15 produced supranormal levels of FVIII activity in the neonatal period. PCR analysis identified viral genomes primarily in the liver, intestine, and spleen, although adenoviral DNA was detected in distal tissues when higher doses of adenovirus were administered. These studies show that transuterine i.p. injection of adenoviral vectors produces therapeutic levels of circulating FVIII throughout the neonatal period. The future development of efficient and persisting vectors that produce long-term gene expression may allow for in utero correction of genetic diseases originating in the fetal liver, hematopoietic stem cells, as well as other tissues. PMID:10557319

  3. An algorithm for temperature correcting substrate moisture measurements: aligning substrate moisture responses with environmental drivers in polytunnel-grown strawberry plants

    NASA Astrophysics Data System (ADS)

    Goodchild, Martin; Janes, Stuart; Jenkins, Malcolm; Nicholl, Chris; Kühn, Karl

    2015-04-01

    The aim of this work is to assess the use of temperature corrected substrate moisture data to improve the relationship between environmental drivers and the measurement of substrate moisture content in high porosity soil-free growing environments such as coir. Substrate moisture sensor data collected from strawberry plants grown in coir bags installed in a table-top system under a polytunnel illustrates the impact of temperature on capacitance-based moisture measurements. Substrate moisture measurements made in our coir arrangement possess the negative temperature coefficient of the permittivity of water where diurnal changes in moisture content oppose those of substrate temperature. The diurnal substrate temperature variation was seen to range from 7° C to 25° C resulting in a clearly observable temperature effect in substrate moisture content measurements during the 23 day test period. In the laboratory we measured the ML3 soil moisture sensor (ThetaProbe) response to temperature in Air, dry glass beads and water saturated glass beads and used a three-phase alpha (α) mixing model, also known as the Complex Refractive Index Model (CRIM), to derive the permittivity temperature coefficients for glass and water. We derived the α value and estimated the temperature coefficient for water - for sensors operating at 100MHz. Both results are good agreement with published data. By applying the CRIM equation with the temperature coefficients of glass and water the moisture temperature coefficient of saturated glass beads has been reduced by more than an order of magnitude to a moisture temperature coefficient of

  4. Selecting the correct weighting factors for linear and quadratic calibration curves with least-squares regression algorithm in bioanalytical LC-MS/MS assays and impacts of using incorrect weighting factors on curve stability, data quality, and assay performance.

    PubMed

    Gu, Huidong; Liu, Guowen; Wang, Jian; Aubry, Anne-Franoise; Arnold, Mark E

    2014-09-16

    A simple procedure for selecting the correct weighting factors for linear and quadratic calibration curves with least-squares regression algorithm in bioanalytical LC-MS/MS assays is reported. The correct weighting factor is determined by the relationship between the standard deviation of instrument responses (?) and the concentrations (x). The weighting factor of 1, 1/x, or 1/x(2) should be selected if, over the entire concentration range, ? is a constant, ?(2) is proportional to x, or ? is proportional to x, respectively. For the first time, we demonstrated with detailed scientific reasoning, solid historical data, and convincing justification that 1/x(2) should always be used as the weighting factor for all bioanalytical LC-MS/MS assays. The impacts of using incorrect weighting factors on curve stability, data quality, and assay performance were thoroughly investigated. It was found that the most stable curve could be obtained when the correct weighting factor was used, whereas other curves using incorrect weighting factors were unstable. It was also found that there was a very insignificant impact on the concentrations reported with calibration curves using incorrect weighting factors as the concentrations were always reported with the passing curves which actually overlapped with or were very close to the curves using the correct weighting factor. However, the use of incorrect weighting factors did impact the assay performance significantly. Finally, the difference between the weighting factors of 1/x(2) and 1/y(2) was discussed. All of the findings can be generalized and applied into other quantitative analysis techniques using calibration curves with weighted least-squares regression algorithm. PMID:25157966

  5. Correction of the equilibrium temperature caused by slight evaporation of water in protein crystal growth cells during long-term space experiments at International Space Station.

    PubMed

    Fujiwara, Takahisa; Suzuki, Yoshihisa; Yoshizaki, Izumi; Tsukamoto, Katsuo; Murayama, Kenta; Fukuyama, Seijiro; Hosokawa, Kouhei; Oshi, Kentaro; Ito, Daisuke; Yamazaki, Tomoya; Tachibana, Masaru; Miura, Hitoshi

    2015-08-01

    The normal growth rates of the {110} faces of tetragonal hen egg-white lysozyme crystals, R, were measured as a function of the supersaturation σ parameter using a reflection type interferometer under μG at the International Space Station (NanoStep Project). Since water slightly evaporated from in situ observation cells during a long-term space station experiment for several months, equilibrium temperature T(e) changed, and the actual σ, however, significantly increased mainly due to the increase in salt concentration C(s). To correct σ, the actual C(s) and protein concentration C(p), which correctly represent the measured T(e) value in space, were first calculated. Second, a new solubility curve with the corrected C(s) was plotted. Finally, the revised σ was obtained from the new solubility curve. This correction method successfully revealed that the 2.8% water was evaporated from the solution, leading to 2.8% increase in the C(s) and C(p) of the solution. PMID:26329200

  6. Factors Influencing the Completion of the GED in a Federal Correctional Setting a Multiple Regression Correlation-Predictive Study

    ERIC Educational Resources Information Center

    Akers, Kimberly

    2013-01-01

    Correctional education's primary goal is to reduce recidivism and increase employment among ex-offenders. The Bureau of Prison's practical goal in its mandatory GED program is to maximize the number of inmates obtaining the GED in a given time period. The purpose of this research is to model the number of instructional hours an inmate

  7. Correcting artifacts in transition to a wound optic fiber: Example from high-resolution temperature profiling in the Dead Sea

    NASA Astrophysics Data System (ADS)

    Arnon, Ali; Selker, John; Lensky, Nadav

    2014-06-01

    Spatial resolution fiber-optic cables allow for detailed observation of thermally complex heterogeneous hydrologic systems. A commercially produced high spatial resolution helically wound optic fiber sensing cable is employed in the Dead Sea, in order to study the dynamics of thermal stratification of the hypersaline lake. Structured spatial artifacts were found in the data from the first 10 m of cable (110 m of fiber length) following the transition from straight fiber optic. The Stokes and Anti-Stokes signals indicate that this is the result of differential attenuation, thought to be due to cladding losses. Though the overall spatial form of the loss was consistent, the fine structure of the loss changed significantly in time, and was strongly asymmetrical, and thus was not amenable to standard calibration methods. Employing the fact that the cable was built with a duplex construction, and using high-precision sensors mounted along the cable, it was possible to correct the artifact in space and time, while retaining the high-quality of data obtained in the early part of the cable (prior to significant optical attenuation). The defect could easily be overlooked; however, reanalyzing earlier experiments, we have observed the same issue with installations employing similar cables in Oregon and France, so with this note we both alert the community to this persistent concern and provide an approach to correct the data in case of similar problems.

  8. Influence of environmental factors on infrared eye temperature measurements in cattle.

    PubMed

    Church, J S; Hegadoren, P R; Paetkau, M J; Miller, C C; Regev-Shoshani, G; Schaefer, A L; Schwartzkopf-Genswein, K S

    2014-02-01

    Environmental factors were evaluated to determine potential limitations in using cattle eye temperatures obtained through infrared thermography (IRT) for early disease detection systems or in animal welfare research studies. The effects of the following factors on IRT eye temperatures in cattle and a fabricated surrogate "eye" were evaluated: camera to object distance, wind speed, camera settings (distance, emissivity, and humidity), and solar loading. Wind speed in both live animals and using a surrogate "eye" was found to decrease the IRT temperature. In the presence of ∼ 7 km/h wind, the mean IRT eye temperature decreased by 0.43 ± 0.13 °C and; at higher wind speeds (∼ 12 km/h), the temperature decreased by 0.78 ± 0.33 °C. Direct sunlight was found to increase the IRT eye temperature by 0.56 ± 0.36 °C. It was determined that environmental factors impact IRT temperature measurements significantly and therefore must be managed to ensure reproducible and accurate readings. PMID:24290729

  9. Conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation 1948--1951. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Denham, D.H.; Mart, E.I.; Thiede, M.E.

    1993-09-01

    This report is a part of the Hanford Environmental Dose Reconstruction (HEDR) Project, whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. The key radionuclide emitted that would affect the radiation dose was iodine-131 (Napier 1992). Because the early methods of measuring iodine-131 were not comparable to later techniques, conversion and correction factors are needed to convert the historical measurement data into concentration values that would be determined using today`s knowledge and technologies. This report describes the conversion and correction factors developed for reconstructing historical measurements of iodine-131 in Hanford-area vegetation, which was collected from 1948 through the end of December 1951.

  10. A physically based algorithm for non-blackbody correction of the cloud top temperature for the convective clouds

    NASA Astrophysics Data System (ADS)

    Wang, C.; Luo, Z. J.; Chen, X.; Zeng, X.; Tao, W.; Huang, X.

    2012-12-01

    Cloud top temperature is a key parameter to retrieval in the remote sensing of convective clouds. Passive remote sensing cannot directly measure the temperature at the cloud tops. Here we explore a synergistic way of estimating cloud top temperature by making use of the simultaneous passive and active remote sensing of clouds (in this case, CloudSat and MODIS). Weighting function of the MODIS 11?m band is explicitly calculated by feeding cloud hydrometer profiles from CloudSat retrievals and temperature and humidity profiles based on ECMWF ERA-interim reanalysis into a radiation transfer model. Among 19,699 tropical deep convective clouds observed by the CloudSat in 2008, the averaged effective emission level (EEL, where the weighting function attains its maximum) is at optical depth 0.91 with a standard deviation of 0.33. Furthermore, the vertical gradient of CloudSat radar reflectivity, an indicator of the fuzziness of convective cloud top, is linearly proportional to, d_{CTH-EEL}, the distance between the EEL of 11?m channel and cloud top height (CTH) determined by the CloudSat when d_{CTH-EEL}<0.6km. Beyond 0.6km, the distance has little sensitivity to the vertical gradient of CloudSat radar reflectivity. Based on these findings, we derive a formula between the fuzziness in the cloud top region, which is measurable by CloudSat, and the MODIS 11?m brightness temperature assuming that the difference between effective emission temperature and the 11?m brightness temperature is proportional to the cloud top fuzziness. This formula is verified using the simulated deep convective cloud profiles by the Goddard Cumulus Ensemble model. We further discuss the application of this formula in estimating cloud top buoyancy as well as the error characteristics of the radiative calculation within such deep-convective clouds.

  11. Conversion and correction factors for historical measurements of Iodine-131 in Hanford-area vegetation, 1945--1947: Draft. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Mart, E.I.; Denham, D.H.; Thiede, M.E.

    1993-05-01

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. The report describes in detail the reconstructed conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation which was collected from the beginning of October 1945 through the end of December 1947.

  12. Clinical Practice Variability in Temperature Correction of Arterial Blood Gas Measurements and Outcomes in Hypothermia-Treated Patients After Cardiac Arrest.

    PubMed

    Terman, Samuel Waller; Nicholas, Katherine S; Hume, Benjamin; Silbergleit, Robert

    2015-09-01

    Mechanical ventilation in patients treated with mild therapeutic hypothermia (MTH) for the postcardiac arrest syndrome may be challenging given changes in solubility of arterial blood gases (ABGs) with cooling. Whether ABG measurements should be temperature corrected (TC) remain unknown. We sought to describe practice variability in TC at a single institution and explored the association between TC and neurological outcome. We conducted a retrospective cohort study reviewing electronic health records of all patients treated with MTH after cardiac arrest. We examined whether the percentage of TC ABGs relative to total number of ABGs drawn for each subject during hypothermia was associated with the neurological outcome at hospital discharge and 6-12-month follow-up. The cerebral performance category of 1-2 was defined as a favorable outcome in the logistic regression models. 1223 ABGs were obtained during MTH on 122 subjects over 6 years. TC was never used in 72 subjects (59%; no TC group), made available in 1-74% of ABGs in 17 subjects (14%; intermediate TC group), and made available in ≥75% of ABGs in 33 subjects (27%; mostly TC group). Groups differed in the proportion of subjects with shockable presenting rhythms (47% vs. 47% vs. 76%, p=0.02) and admitting ICU (p=0.005). Favorable 6-month outcomes were more common in the mostly TC than no TC group (48% vs. 25%; OR [95% CI]: 2.9 [1.2-7.1]), but not after adjustment (OR 1.5, 95% CI 0.33-6.9). There was substantial practice variability in the temperature correction strategy. Availability of temperature-corrected ABGs was not associated with improved neurological outcomes after adjusting for covariates. PMID:26172837

  13. Application of the Exradin W1 scintillator to determine Ediode 60017 and microDiamond 60019 correction factors for relative dosimetry within small MV and FFF fields

    NASA Astrophysics Data System (ADS)

    Underwood, T. S. A.; Rowland, B. C.; Ferrand, R.; Vieillevigne, L.

    2015-09-01

    In this work we use EBT3 film measurements at 10 MV to demonstrate the suitability of the Exradin W1 (plastic scintillator) for relative dosimetry within small photon fields. We then use the Exradin W1 to measure the small field correction factors required by two other detectors: the PTW unshielded Ediode 60017 and the PTW microDiamond 60019. We consider on-axis correction-factors for small fields collimated using MLCs for four different TrueBeam energies: 6 FFF, 6 MV, 10 FFF and 10 MV. We also investigate percentage depth dose and lateral profile perturbations. In addition to high-density effects from its silicon sensitive region, the Ediode exhibited a dose-rate dependence and its known over-response to low energy scatter was found to be greater for 6 FFF than 6 MV. For clinical centres without access to a W1 scintillator, we recommend the microDiamond over the Ediode and suggest that limits of usability, field sizes below which a detector introduces unacceptable errors, can form a practical alternative to small-field correction factors. For a dosimetric tolerance of 2% on-axis, the microDiamond might be utilised down to 10?mm and 15?mm field sizes for 6 MV and 10 MV, respectively.

  14. A trapezoid approach for the experimental total-to-peak efficiency curve used in the determination of true coincidence summing correction factors in a HPGe detector

    NASA Astrophysics Data System (ADS)

    ?ahiner, Eren; Meri, Niyazi

    2014-03-01

    In this work, a simple method for true coincidence correction is suggested for a voluminous source measured in close detection geometry for a HPGe detector. TrueCoinc program based on Sudr's algorithm was used to determine true coincidence summing correction (TCS) factors by using full energy peak (FEP) efficiency, and total-to-peak (TTP) efficiency curves in which experimental efficiencies are obtained from almost coincident-free radionuclides such as 54Mn, 57Co, 65Zn, 109Cd, 137Cs and 241Am. In order to calculate TTP efficiency curve three different approaches were tested. One of them is new and here called trapezoid approach which was used successfully in determining total count of spectrum for the TTP efficiency curves. According to different TTP determination methods, the changes in true coincidence factors are observed. The FEP efficiency curves are also established for a cylindrical source. Then, TCS factors were determined for the particular peaks of daughters of 226Ra, 238U, and 232Th using the suggested method. Those activities measured from some certified reference materials such as IAEA RGU-1 and RGTh-1 are used to validate the present TCS correction procedure.

  15. A method for determining an effective porosity correction factor for thermal conductivity in fast reactor uranium-plutonium oxide fuel pellets

    NASA Astrophysics Data System (ADS)

    Inoue, Masaki; Abe, Kazuyuki; Sato, Isamu

    2000-10-01

    A reliable method has been developed for determining an effective porosity correction factor for calculating a realistic thermal conductivity for fast reactor uranium-plutonium (mixed) oxide fuel pellets. By using image analysis of the ceramographs of transverse sections of mixed-oxide fuel pellets, the fuel morphology could be classified into two basic types. One is a 'two-phase' type that consists of small pores dispersed in the fuel matrix. The other is a 'three-phase' type that has large pores in addition to the small pores dispersed in the fuel matrix. The pore sizes are divided into two categories, large and small, at the 30 ?m area equivalent diameter. These classifications lead to an equation for calculating an effective porosity correction factor by accounting for the small and large pore volume fractions and coefficients. This new analytical method for determining the effective porosity correction factor for calculating the realistic thermal conductivity of mixed-oxide fuel was also experimentally confirmed for high-, medium- and low-density fuel pellets.

  16. Application of the Exradin W1 scintillator to determine Ediode 60017 and microDiamond 60019 correction factors for relative dosimetry within small MV and FFF fields.

    PubMed

    Underwood, T S A; Rowland, B C; Ferrand, R; Vieillevigne, L

    2015-09-01

    In this work we use EBT3 film measurements at 10 MV to demonstrate the suitability of the Exradin W1 (plastic scintillator) for relative dosimetry within small photon fields. We then use the Exradin W1 to measure the small field correction factors required by two other detectors: the PTW unshielded Ediode 60017 and the PTW microDiamond 60019. We consider on-axis correction-factors for small fields collimated using MLCs for four different TrueBeam energies: 6 FFF, 6 MV, 10 FFF and 10 MV. We also investigate percentage depth dose and lateral profile perturbations. In addition to high-density effects from its silicon sensitive region, the Ediode exhibited a dose-rate dependence and its known over-response to low energy scatter was found to be greater for 6 FFF than 6 MV. For clinical centres without access to a W1 scintillator, we recommend the microDiamond over the Ediode and suggest that 'limits of usability', field sizes below which a detector introduces unacceptable errors, can form a practical alternative to small-field correction factors. For a dosimetric tolerance of 2% on-axis, the microDiamond might be utilised down to 10 mm and 15 mm field sizes for 6 MV and 10 MV, respectively. PMID:26271097

  17. Correction factors for A1SL ionization chamber dosimetry in TomoTherapy: Machine-specific, plan-class, and clinical fields

    SciTech Connect

    Gago-Arias, Araceli; Rodriguez-Romero, Ruth; Sanchez-Rubio, Patricia; Miguel Gonzalez-Castano, Diego; Gomez, Faustino; Nunez, Luis; Palmans, Hugo; Sharpe, Peter; Pardo-Montero, Juan

    2012-04-15

    Purpose: Recently, an international working group on nonstandard fields presented a new formalism for ionization chamber reference dosimetry of small and nonstandard fields [Alfonso et al., Med. Phys. 35, 5179-5186 (2008)] which has been adopted by AAPM TG-148. This work presents an experimental determination of the correction factors for reference dosimetry with an Exradin A1SL thimble ionization chamber in a TomoTherapy unit, focusing on: (i) machine-specific reference field, (ii) plan-class-specific reference field, and (iii) two clinical treatments. Methods: Ionization chamber measurements were performed in the TomoTherapy unit for intermediate (machine-specific and plan-class-specific) calibration fields, based on the reference conditions defined by AAPM TG-148, and two clinical treatments (lung and head-and-neck). Alanine reference dosimetry was employed to determine absorbed dose to water at the point of interest for the fields under investigation. The corresponding chamber correction factors were calculated from alanine to ionization chamber measurements ratios. Results: Two different methods of determining the beam quality correction factor k{sub Q,Q{sub 0}} for the A1SL ionization chamber in this TomoTherapy unit, where reference conditions for conventional beam quality determination cannot be met, result in consistent values. The observed values of overall correction factors obtained for intermediate and clinical fields are consistently around 0.98 with a typical expanded relative uncertainty of 2% (k = 2), which when considered make such correction factors compatible with unity. However, all of them are systematically lower than unity, which is shown to be significant when a hypothesis test assuming a t-student distribution is performed (p=1.8x10{sup -2}). Correction factors k{sub Q{sub c{sub l{sub i{sub n,Q{sub p{sub c{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub p}{sub c}{sub s}{sub r}}}}}}}}}} and k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, which are needed for the computation of field factors for relative dosimetry of clinical beams, have been found to be very close to unity for two clinical treatments. Conclusions: The results indicate that the helical field deliveries in this study (including two clinical fields) do not introduce changes on the ion chamber correction factors for dosimetry. For those two specific clinical cases, ratios of chamber readings accurately represent field output factors. The values observed here for intermediate calibration fields are in agreement with previously published data based on alanine dosimetry but differ from values recently reported obtained via radiochromic dosimetry.

  18. Temperature and donor concentration dependence of the conduction electron Lande g-factor in silicon

    SciTech Connect

    Konakov, Anton A.; Ezhevskii, Alexander A.; Soukhorukov, Andrey V.; Guseinov, Davud V.; Popkov, Sergey A.; Burdov, Vladimir A.

    2013-12-04

    Temperature and donor concentration dependence of the conduction electron g-factor in silicon has been investigated both experimentally and theoretically. We performed electron spin resonance experiments on Si samples doped with different densities of phosphorus and lithium. Theoretical consideration is based on the renormalization of the electron energy in a weak magnetic field by the interaction with possible perturbing agents, such as phonons and impurity centers. In the second-order perturbation theory interaction of the electron subsystem with the lattice vibrations as well as ionized donors results in decreasing the conduction electron g-factor, which becomes almost linear function both of temperature and impurity concentration.

  19. Identification of possible factors influencing temperatures elevation during implant site preparation with piezoelectric technique

    PubMed Central

    Lamazza, Luca; Laurito, Domenica; Lollobrigida, Marco; Brugnoletti, Orlando; Garreffa, Girolamo; De Biase, Alberto

    2014-01-01

    Summary Background Overheating during implant site preparation negatively affects the osseointegration process as well the final outcome of implant rehabilitations. Piezoelectric techniques seem to provide to a gentle implant preparation although few scientific reports have investigated the heat generation and its underlying factors. Purpose To investigate, through a proper methodological approach, the main factors influencing temperature rise during piezoelectric implant site preparation. Materials and methods Different piezoelectric tips (IM1s, IM2, P2-3, IM3, Mectron Medical Technology, Carasco, Italy) have been tested. The experimental set-up consisted in a mechanical positioning device equipped with a load cell and a fluoroptic thermometer. Results The first tip of the sequence (IM1s) generated the highest temperature increasing (?T). The diamond tips (IM1s and P2-3) determined higher ?T values than the smooth tips (IM2 and IM3). Further tests with IM1s suggested that the temperature elevation during the first thirty seconds may be predictive of the maximal temperature as well as of the overall thermal impact. Conclusions Working load, working movements management and bone features resulted to be the main factors influencing temperature rise during piezoelectric implant site preparation. Irrigant temperature and clogging effect may also synergically contribute to the heat generation. PMID:25774245

  20. Do current models correctly predict the L-band terrestrial brightness temperature when crops begin to senesce?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The microwave terrestrial brightness temperature is sensitive to soil moisture, the water content of the first few centimeters of Earth's surface. The European Space Agency will soon launch the Soil Moisture and Ocean Salinity (SMOS) mission, the world's first soil moisture satellite that will measu...

  1. Some factors influencing the sensitivity of body temperature to activity in neonates.

    PubMed

    Waterhouse, J; Weinert, D; Nevill, A; Atkinson, G; Reilly, T

    2000-09-01

    In adult humans, core temperature is influenced by activity; the sensitivity of core temperature to such effects shows a phase dependence and is also influenced by the environment and whether the individual is asleep or awake. We have investigated if similar effects are evident in neonates, in whom thermoregulation and the circadian rhythm of core temperature are not fully developed. Eleven full-term, healthy babies were studied singly (light 07:00-19:00) at 2 days of age and again 4 weeks after birth; between these times, they were tended routinely on a communal ward. On study days, 10-minute recordings were made of rectal and skin (abdominal) temperature, heart rate (HR), and behavioral state. Sensitivities of the temperatures to activity ("arousal") were assessed throughout the 24h by measuring the gradient of (temperature/HR). Sensitivities measured at 01:00, 05:00, 09:00, 13:00, 17:00, and 21:00 were used as dependent variables in stepwise regression and linear regression analyses, with "subjects," "light versus dark," "behavioral state," and "difference between time of measurement and the acrophase of the endogenous component of the temperature rhythm" (ignoring sign) as possible predictors. (Acrophases of the temperature rhythms had been estimated from 24h data purified using the behavioral state record.) Light versus dark acted as a significant predictor of the sensitivity of rectal temperature to arousal on day 2 and week 4, the sensitivity increasing in the light, and there was limited evidence for behavioral state acting as a predictor on day 2. Neither factor was a significant predictor when the sensitivity of the babies' skin temperatures to arousal was investigated. There was also some evidence that the difference between the time of measurement and the temperature acrophase acted as a predictor of sensitivity to arousal in both rectal (day 2) and skin (week 4) temperature, with larger differences decreasing the sensitivity. These results indicate that there are masking effects on body temperature due to arousal in neonates, the size of which depends on both internal and external factors. However, this sensitivity of temperature to arousal shows differences from the sensitivity of temperature to physical activity in both adult humans and adult mice. One possible explanation of this result is that temperature regulation and the circadian system are not fully developed in humans at this age. PMID:11023215

  2. The role of demagnetization factor in determining the true value of the Curie temperature

    SciTech Connect

    Zverev, V.I.; Gimaev, R.R.; Tishin, A.M.; Mudryk, Ya; Gschneidner, Jr., K.A.; Pecharsky, V.K.

    2011-05-20

    The Curie temperature, T{sub c}, is the temperature above which a material loses its long-range ferromagnetic order. Considering the equation of state of a ferromagnet in the mean-field approximation it has been shown theoretically that the value of the demagnetization factor N has a significant influence on the perceived location of T{sub c} on the temperature scale. A series of precise measurements of magnetization using two differently shaped single crystals of high-purity gadolinium was carried out to prove this result experimentally and develop a procedure leading to the 'true' value of T{sub c}.

  3. Temperature-averaged and total free-free Gaunt factors for ? and Maxwellian distributions of electrons

    NASA Astrophysics Data System (ADS)

    de Avillez, Miguel A.; Breitschwerdt, Dieter

    2015-08-01

    Aims: Optically thin plasmas may deviate from thermal equilibrium and thus, electrons (and ions) are no longer described by the Maxwellian distribution. Instead they can be described by ?-distributions. The free-free spectrum and radiative losses depend on the temperature-averaged (over the electrons distribution) and total Gaunt factors, respectively. Thus, there is a need to calculate and make available these factors to be used by any software that deals with plasma emission. Methods: We recalculated the free-free Gaunt factor for a wide range of energies and frequencies using hypergeometric functions of complex arguments and the Clenshaw recurrence formula technique combined with approximations whenever the difference between the initial and final electron energies is smaller than 10-10 in units of z2Ry. We used double and quadruple precisions. The temperature-averaged and total Gaunt factors calculations make use of the Gauss-Laguerre integration with 128 nodes. Results: The temperature-averaged and total Gaunt factors depend on the ? parameter, which shows increasing deviations (with respect to the results obtained with the use of the Maxwellian distribution) with decreasing ?. Tables of these Gaunt factors are provided. Appendices are available in electronic form at http://www.aanda.org

  4. Extrahepatic sources of factor VIII potentially contribute to the coagulation cascade correcting the bleeding phenotype of mice with hemophilia A.

    PubMed

    Zanolini, Diego; Merlin, Simone; Feola, Maria; Ranaldo, Gabriella; Amoruso, Angela; Gaidano, Gianluca; Zaffaroni, Mauro; Ferrero, Alessandro; Brunelleschi, Sandra; Valente, Guido; Gupta, Sanjeev; Prat, Maria; Follenzi, Antonia

    2015-07-01

    A large fraction of factor VIII in blood originates from liver sinusoidal endothelial cells although extrahepatic sources also contribute to plasma factor VIII levels. Identification of cell-types other than endothelial cells with the capacity to synthesize and release factor VIII will be helpful for therapeutic approaches in hemophilia A. Recent cell therapy and bone marrow transplantation studies indicated that Kpffer cells, monocytes and mesenchymal stromal cells could synthesize factor VIII in sufficient amount to ameliorate the bleeding phenotype in hemophilic mice. To further establish the role of blood cells in expressing factor VIII, we studied various types of mouse and human hematopoietic cells. We identified factor VIII in cells isolated from peripheral and cord blood, as well as bone marrow. Co-staining for cell type-specific markers verified that factor VIII was expressed in monocytes, macrophages and megakaryocytes. We additionally verified that factor VIII was expressed in liver sinusoidal endothelial cells and endothelial cells elsewhere, e.g., in the spleen, lungs and kidneys. Factor VIII was well expressed in sinusoidal endothelial cells and Kpffer cells isolated from human liver, whereas by comparison isolated human hepatocytes expressed factor VIII at very low levels. After transplantation of CD34(+) human cord blood cells into NOD/SCID?Null-hemophilia A mice, fluorescence activated cell sorting of peripheral blood showed >40% donor cells engrafted in the majority of mice. In these animals, plasma factor VIII activity 12 weeks after cell transplantation was up to 5% and nine of 12 mice survived after a tail clip-assay. In conclusion, hematopoietic cells, in addition to endothelial cells, express and secrete factor VIII: this information should offer further opportunities for understanding mechanisms of factor VIII synthesis and replenishment. PMID:25911555

  5. Extrahepatic sources of factor VIII potentially contribute to the coagulation cascade correcting the bleeding phenotype of mice with hemophilia A

    PubMed Central

    Zanolini, Diego; Merlin, Simone; Feola, Maria; Ranaldo, Gabriella; Amoruso, Angela; Gaidano, Gianluca; Zaffaroni, Mauro; Ferrero, Alessandro; Brunelleschi, Sandra; Valente, Guido; Gupta, Sanjeev; Prat, Maria; Follenzi, Antonia

    2015-01-01

    A large fraction of factor VIII in blood originates from liver sinusoidal endothelial cells although extrahepatic sources also contribute to plasma factor VIII levels. Identification of cell-types other than endothelial cells with the capacity to synthesize and release factor VIII will be helpful for therapeutic approaches in hemophilia A. Recent cell therapy and bone marrow transplantation studies indicated that Küpffer cells, monocytes and mesenchymal stromal cells could synthesize factor VIII in sufficient amount to ameliorate the bleeding phenotype in hemophilic mice. To further establish the role of blood cells in expressing factor VIII, we studied various types of mouse and human hematopoietic cells. We identified factor VIII in cells isolated from peripheral and cord blood, as well as bone marrow. Co-staining for cell type-specific markers verified that factor VIII was expressed in monocytes, macrophages and megakaryocytes. We additionally verified that factor VIII was expressed in liver sinusoidal endothelial cells and endothelial cells elsewhere, e.g., in the spleen, lungs and kidneys. Factor VIII was well expressed in sinusoidal endothelial cells and Küpffer cells isolated from human liver, whereas by comparison isolated human hepatocytes expressed factor VIII at very low levels. After transplantation of CD34+ human cord blood cells into NOD/SCIDγNull-hemophilia A mice, fluorescence activated cell sorting of peripheral blood showed >40% donor cells engrafted in the majority of mice. In these animals, plasma factor VIII activity 12 weeks after cell transplantation was up to 5% and nine of 12 mice survived after a tail clip-assay. In conclusion, hematopoietic cells, in addition to endothelial cells, express and secrete factor VIII: this information should offer further opportunities for understanding mechanisms of factor VIII synthesis and replenishment. PMID:25911555

  6. Novel, cyclic heat dissipation method for the correction of natural temperature gradients in sap flow measurements. Part 1. Theory and application.

    PubMed

    Lubczynski, Maciek W; Chavarro-Rincon, Diana; Roy, Jean

    2012-07-01

    Natural temperature gradient (NTG) can be a significant problem in thermal sap flow measurements, particularly in dry environments with sparse vegetation. To resolve this problem, we propose a novel correction method called cyclic heat dissipation (CHD) in its thermal dissipation probe (TDP) application. The CHD method is based on cyclic, switching ON/OFF power schema measurements and a three-exponential model, extrapolating measured signal to steady state thermal equilibrium. The extrapolated signal OFF represents NTG, whereas the extrapolated signal ON represents standard TDP signal, biased by NTG. Therefore, subtraction of the OFF signal from the ON signal allows defining the unbiased TDP signal, finally processed according to standard Granier calibration. The in vivo Kalahari measurements were carried out in three steps on four different tree species, first as NTG, then as standard TDP and finally in CHD mode, each step for ?1-2 days. Afterwards, each tree was separated from its stem following modified Roberts' (1977) procedure, and CHD verification was applied. The typical NTG varying from ?0.5 C during night-time to -1 C during day-time, after CHD correction, resulted in significant reduction of sap flux densities (J(p)) as compared with the standard TDP, particularly distinct for low J(p). The verification of the CHD method indicated ?20% agreement with the reference method, largely dependent on the sapwood area estimate. The proposed CHD method offers the following advantages: (i) in contrast to any other NTG correction method, it removes NTG bias from the measured signal by using in situ, extrapolated to thermal equilibrium signal; (ii) it does not need any specific calibration making use of the standard Granier calibration; (iii) it provides a physical background to the proposed NTG correction; (iv) it allows for power savings; (v) it is not tied to TDP, and so can be adapted to other thermal methods. In its current state, the CHD data processing is not yet fully automated. PMID:22611074

  7. Functional Correction of Large Factor VIII Gene Chromosomal Inversions in Hemophilia A Patient-Derived iPSCs Using CRISPR-Cas9.

    PubMed

    Park, Chul-Yong; Kim, Duk Hyoung; Son, Jeong Sang; Sung, Jin Jea; Lee, Jaehun; Bae, Sangsu; Kim, Jong-Hoon; Kim, Dong-Wook; Kim, Jin-Soo

    2015-08-01

    Hemophilia A is an X-linked genetic disorder caused by mutations in the F8 gene, which encodes the blood coagulation factor VIII. Almost half of all severe hemophilia A cases result from two gross (140-kbp or 600-kbp) chromosomal inversions that involve introns 1 and 22 of the F8 gene, respectively. We derived induced pluripotent stem cells (iPSCs) from patients with these inversion genotypes and used CRISPR-Cas9 nucleases to revert these chromosomal segments back to the WT situation. We isolated inversion-corrected iPSCs with frequencies of up to 6.7% without detectable off-target mutations based on whole-genome sequencing or targeted deep sequencing. Endothelial cells differentiated from corrected iPSCs expressed the F8 gene and functionally rescued factor VIII deficiency in an otherwise lethal mouse model of hemophilia. Our results therefore provide a proof of principle for functional correction of large chromosomal rearrangements in patient-derived iPSCs and suggest potential therapeutic applications. PMID:26212079

  8. Factors associated with survival in the herd for dairy cows following surgery to correct left displaced abomasum.

    PubMed

    Reynen, Jennifer L; Kelton, David F; LeBlanc, Stephen J; Newby, Nathalie C; Duffield, Todd F

    2015-06-01

    Left displaced abomasum (LDA) is a common problem in dairy cows. There have been numerous studies focused on predicting prognosis for right displaced abomasal corrective surgery, but a paucity of studies exist focused on more common LDA surgeries. Our objective was to determine if survival to 60 d or 1 yr after surgery could be predicted from the physical exam findings, periparturient disease status, and a biochemical profile from a blood sample obtained at the time of LDA diagnosis. Blood β-hydroxybutyrate (BHBA) concentrations were measured immediately using a hand-held meter. Data obtained from CanWest DHI (Guelph, ON, Canada) for all of the study subjects (n=179 cases, by 24 veterinarians from 4 clinics), including cull date, cull reason, and test-day milk production. Cows were classified based on whether or not they were culled within 60 d or 1 yr of surgery. Based on logistic regression, cows that had dystocia [odds ratio (OR)=13, 95% confidence interval (CI)=7-26] or were not ketotic (blood BHBA<1.2 mmol/L; OR=3, 95% CI=1.03-9) at the time of corrective surgery were more likely to be culled within 60 d. Higher serum concentrations of BHBA (OR=0.95, 95% CI=0.92-0.98), nonesterified fatty acids (OR=0.81, 95% CI=0.75-0.88), and Mg (OR=0.49, 95% CI=0.35-0.68) all had a protective effect against culling within 1 yr of LDA surgery. Based on survival analysis, longevity in the herd for 365 d following corrective surgery was associated with higher BHBA and Mg at the time of LDA diagnosis before surgery, as well as milk production following surgery. PMID:25892696

  9. Temperature as a determinant factor for increased and reproducible in vitro pollen germination in Arabidopsis thaliana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite much effort, a robust protocol for in vitro germination of Arabidopsis thaliana pollen was still elusive. Here we show that controlled temperatures, a largely disregarded factor in previous studies, and a simple optimized medium, solidified or liquid, yielded pollen germination rates above 8...

  10. Temperature trumps light: Teasing apart interactive factors controlling non-indigenous Zostera japonica growth

    EPA Science Inventory

    In the Pacific Northwest Zostera marina and Z. japonica co-exist by occupying separate elevation niches. We conducted two mesocosm experiments to evaluate light and temperature as factors controlling the disjunct distribution of congeners. The first study tests the hypothesis t...

  11. Relations of Tualatin River water temperatures to natural and human-caused factors

    USGS Publications Warehouse

    Risley, John C.

    1997-01-01

    Aquatic research has long shown that the survival of cold-water fish, such as salmon and trout, decreases markedly as water temperatures increase above a critical threshold, particularly during sensitive life stages of the fish. In an effort to improve the overall health of aquatic ecosystems, the State of Oregon in 1996 adopted a maximum water-temperature standard of 17.8 degrees Celsius (68 degrees Fahrenheit), based on a 7-day moving average of daily maximum temperatures, for most water bodies in the State. Anthropogenic activities are not permitted to raise the temperature of a water body above this level. In the Tualatin River, a tributary of the Willamette River located in northwestern Oregon, water temperatures periodically surpass this threshold during the low-flow summer and fall months.An investigation by the U.S. Geological Survey quantified existing seasonal, diel, and spatial patterns of water temperatures in the main stem of the river, assessed the relation of water temperatures to natural climatic conditions and anthropogenic factors (such as wastewater-treatment-plant effluent and modification of riparian shading), and assessed the impact of various flow management practices on stream temperatures. Half-hourly temperature measurements were recorded at 13 monitoring sites from river mile (RM) 63.9 to RM 3.4 from May to November of 1994. Four synoptic water- temperature surveys also were conducted in the upstream and downstream vicinities of two wastewater-treatment-plant outfalls. Temperature and streamflow time-series data were used to calibrate two dynamic-flow heat-transfer models, DAFLOW-BLTM (RM 63.9-38.4) and CE-QUAL-W2 (RM 38.4-3.4). Simulations from the models provided a basis for approximating 'natural' historical temperature patterns, performing effluent and riparian-shading sensitivity analyses, and evaluating mitigation management scenarios under 1994 climatic conditions. Findings from the investigation included (1) under 'natural' conditions the temperature of the river would exceed the State standard of 17.8 degrees Celsius at many locations during the low-flow season, (2) current operation of wastewater-treatment plants increases the temperature of the river downstream of the plants under low-flow conditions, (3) river temperature is significantly affected by riparian shade variations along both the tributaries and the main stem, (4) flow releases during the low-flow season from the Henry Hagg Lake reservoir decrease the river temperature in the upper section, and (5) removal of a low diversion dam at RM 3.4 would slightly decrease temperatures below RM 10.0.

  12. Factors That Affect Riverbank Filtrate Water Temperature in Daesan Plants, Changwon, Korea

    NASA Astrophysics Data System (ADS)

    Shin, J.; Lim, J.; Lee, K.; Jung, W.; Kim, H.

    2008-12-01

    City of Changwon, Korea, has been using some of riverbank filtrate water for the indoor air-conditioning of Daesan purification plants since 2006. In this method, the most important factor to determine efficiency of heating and cooling is the temperature of the filtrate water. Thus, it is required to predict the available range of groundwater temperature in the case of changing pumping rate, pumping location or in the case of long term operation. Numerical simulation of temperature profile of riverbank filtrate water in Daesan plants using HydroGeoSphere shows that the primary factor in determining filtrate water temperature is the pumping rate. Distance from the river to the wells is long enough to equalize subsurface water temperature through its penetration path and all of the well screen sections are located at the depth of 30 m below surface which is part of the local aquifer. This is why the horizontal distance from the river to each well and the installed screen depth are less important than the pumping rate to determine filtrate water temperature in this facility. It also shows that maintaining the facility operation with present pumping rate for the next 30 years will not cause any significant change of water temperature. However, following the new plan of the city to install additional 37 wells with 6 times higher pumping rate than the current rate might cause about 2? decrease in filtrate water temperature in 10 years after the extension. All of these results demonstrate that basic hydrological study such as aquifer heterogeneity or pumping capacity is prerequisite for calculating and predicting extracted water temperature in riverbank filtration system.

  13. A New Method to Measure Temperature and Burner Pattern Factor Sensing for Active Engine Control

    NASA Technical Reports Server (NTRS)

    Ng, Daniel

    1999-01-01

    The determination of the temperatures of extended surfaces which exhibit non-uniform temperature variation is very important for a number of applications including the "Burner Pattern Factor" (BPF) of turbine engines. Exploratory work has shown that use of BPF to control engine functions can result in many benefits, among them reduction in engine weight, reduction in operating cost, increase in engine life, while attaining maximum engine efficiency. Advanced engines are expected to operate at very high temperature to achieve high efficiency. Brief exposure of engine components to higher than design temperatures due to non-uniformity in engine burner pattern can reduce engine life. The engine BPF is a measure of engine temperature uniformity. Attainment of maximum temperature uniformity and high temperatures is key to maximum efficiency and long life. A new approach to determine through the measurement of just one radiation spectrum by a multiwavelength pyrometer is possible. This paper discusses a new temperature sensing approach and its application to determine the BPF.

  14. High Temperature as a Risk Factor for Infectious Diarrhea in Shanghai, China

    PubMed Central

    Zhou, Xiaodan; Zhou, Yanbing; Chen, Renjie; Ma, Wenjuan; Deng, Haiju; Kan, Haidong

    2013-01-01

    Background Recent studies indicate that ambient temperature could be a risk factor for infectious diarrhea, but evidence for such a relation is limited in China. Methods We investigated the short-term association between daily temperature and physician-diagnosed infectious diarrhea during 2008–2010 in Shanghai, China. We adopted a time-series approach to analyze the data and a quasi-Poisson regression model with a natural spline-smoothing function to adjust for long-term and seasonal trends, as well as other time-varying covariates. Results There was a significant association between temperature and outpatient visits for diarrhea. A 1°C increase in the 6-day moving average of temperature was associated with a 2.68% (95% CI: 1.83%, 3.52%) increase in outpatient visits for diarrhea. We did not find a significant association between rainfall and infectious diarrhea. Conclusions High temperature might be a risk factor for infectious diarrhea in Shanghai. Public health programs should focus on preventing diarrhea related to high temperature among city residents. PMID:23994865

  15. Proteomic comparison of Ralstonia solanacearum strains reveals temperature dependent virulence factors

    PubMed Central

    2014-01-01

    Background Ralstonia solanacearum, the causal agent of bacterial wilt, is a genetically diverse bacterial plant pathogen present in tropical and subtropical regions of the world that infects more than 200 plant species, including economically important solanaceous crops. Most strains of R. solanacearum are only pathogenic at temperatures between 25 to 30C with strains that can cause disease below 20C considered a threat to agriculture in temperate areas. Identifying key molecular factors that distinguish strains virulent at cold temperatures from ones that are not is needed to develop effective management tools for this pathogen. We compared protein profiles of two strains virulent at low temperature and two strains not virulent at low temperature when incubated in the rhizosphere of tomato seedlings at 30 and 18C using quantitative 2D DIGE gel methods. Spot intensities were quantified and compared, and differentially expressed proteins were sequenced and identified by mass spectrometry (MS/MS). Results Four hundred and eighteen (418) differentially expressed protein spots sequenced produced 101 unique proteins. The identified proteins were classified in the Gene Ontology biological processes categories of metabolism, cell processes, stress response, transport, secretion, motility, and virulence. Identified virulence factors included catalase (KatE), exoglucanase A (ChbA), drug efflux pump, and twitching motility porin (PilQ). Other proteins identified included two components of a putative type VI secretion system. We confirmed differential expression of 13 candidate genes using real time PCR techniques. Global regulators HrpB and HrpG also had temperature dependent expression when quantified by real time PCR. Conclusions The putative involvement of the identified proteins in virulence at low temperature is discussed. The discovery of a functional type VI secretion system provides a new potential virulence mechanism to explore. The global regulators HrpG and HrpB, and the protein expression profiles identified suggest that virulence at low temperatures can be partially explained by differences in regulation of virulence factors present in all the strains. PMID:24725348

  16. Correction of temperature and bulk electrical conductivity effects on dielectric permittivity measurements using ECH2O EC-5, TE and 5TE sensors

    NASA Astrophysics Data System (ADS)

    Rosenbaum, U.; Bogena, H. R.; Huisman, J. A.; Vrba, J.; Vereecken, H.

    2009-12-01

    For a monitoring of dynamic spatiotemporal soil moisture patterns at the catchment scale, automated and continuously measuring systems that provide spatial coverage and high temporal resolution are needed. Promising techniques like wireless sensor networks (e.g. SoilNet) have to integrate sensors that are able to measure dielectric permittivity accurately as the first step to an accurate soil water content determination. The measurement accuracy of low-budget electromagnetic soil water content sensors operating at a low frequency range (e.g. < 100 MHz) is often deteriorated by temperature and bulk electrical conductivity effects. The objective of this study is to derive correction functions for such temperature and bulk electrical conductivity effects on the electric circuitry of ECH2O EC-5, TE and 5TE sensors. We used dielectric standard liquids (2-isopropoxyethanol- and dioxane-dionized water mixtures) for two different laboratory experiments. In the first experiment, the temperatures of eight standard liquids with permittivities ranging from 7 to 42 were varied from 5 to 40 C. The apparent ECH2O sensor permittivity Ka was estimated by applying sensor-specific sensor response-permittivity relationships. The reference static permittivity ?s as a function of temperature was obtained by curve fitting of the Cole-Cole model to open-ended coaxial probe measurements. The difference between the sensor and reference permittivity is due to temperature effects on the sensor circuitry (?Ka). In the second experiment, the apparent ECH2O sensor permittivity as a function of bulk electrical conductivity was determined by adding NaCl to the standard liquids. The temperature experiments showed a negative gradient ??s/T that decreased further with the reference permittivity as expected from the higher water content of the high permittivity standard liquids. We found an empirical 2nd order polynomial function that accurately describes the influence of temperature and water/isopropoxyethanol volume fraction on the reference static permittivity. This relationship was used to determine the temperature effects on the sensor circuitry. The highest thermal effect was obtained for a high water volume fraction for low (permittivity underestimation of ~ 3.5) and high temperature (permittivity overestimation of ~ 2.5). This effect was similar for all three probe types. The temperature effects on the sensor circuitry can be approximated with an empirical 3rd order polynomial function. The conductivity experiment suggests that conductivity has a more distinct effect on the sensor circuitry than temperature. The highest permittivity underestimation occurs for high water volume fractions and bulk soil conductivity between 0.8 and 1.5 dS/m (~8 permittivity units for the EC-5, 5TE; ~16 permittivity units for the TE). The effect of conductivity on dielectric permittivity measurements with ECH2O sensors can be described using empirical 3rd order polynomial functions. The use of temperature and bulk electrical conductivity correction functions improves the accuracy of soil water content measurements using the ECH2O sensors.

  17. The Aquarius Scatterometer: An Active System for Measuring Surface Roughness for Sea-Surface Brightness Temperature Correction

    NASA Technical Reports Server (NTRS)

    Freedman, Adam; McWatters, Dalia; Spencer, Michael

    2006-01-01

    The Aquarius scatterometer is a total-power L-band radar system for estimating ocean surface roughness. Its measurements will enable the removal of wind effects from the Aquarius radiometer ocean-surface brightness temperature measurements being used to retrieve ocean salinity. The Aquarius scatterometer is a relatively simple, low-spatial resolution power-detecting radar, without ranging capability. But to meet its science requirement, it must be very stable, with repeatability on the order of 0.1 dB over several days, and calibrated accuracy to this level over several months. Data from this instrument over land as well as ocean areas will be available for a variety of geophysical applications.

  18. Neonatal helper-dependent adenoviral vector gene therapy mediates correction of hemophilia A and tolerance to human factor VIII.

    PubMed

    Hu, Chuhong; Cela, Racel G; Suzuki, Masataka; Lee, Brendan; Lipshutz, Gerald S

    2011-02-01

    Neonatal gene therapy is a promising strategy for treating a number of congenital diseases diagnosed shortly after birth as expression of therapeutic proteins during postnatal life may limit the pathologic consequences and result in a potential "cure." Hemophilia A is often complicated by the development of antibodies to recombinant protein resulting in treatment failure. Neonatal administration of vectors may avoid inhibitory antibody formation to factor VIII (FVIII) by taking advantage of immune immaturity. A helper-dependent adenoviral vector expressing human factor VIII was administered i.v. to neonatal hemophilia A knockout mice. Three days later, mice produced high levels of FVIII. Levels declined rapidly with animal growth to 5 wk of age with stable factor VIII expression thereafter to >1 y of age. Decline in factor VIII expression was not related to cell-mediated or humoral responses with lack of development of antibodies to capsid or human factor VIII proteins. Subsequent readministration and augmentation of expression was possible as operational tolerance was established to factor VIII without development of inhibitors; however, protective immunity to adenovirus remained. PMID:21245323

  19. Efficacy of a unique omega-3 formulation on the correction of nutritional deficiency and its effects on cardiovascular disease risk factors in a randomized controlled VASCAZEN() REVEAL Trial.

    PubMed

    Shaikh, Nisar A; Yantha, Jason; Shaikh, Sabah; Rowe, William; Laidlaw, Maggie; Cockerline, Carla; Ali, Abbas; Holub, Bruce; Jackowski, George

    2014-11-01

    Low blood levels of long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) have been reported to be associated with increased risk for cardiovascular disease (CVD) deaths. Systematic studies measuring LC n-3 PUFA blood levels (pre and post-treatment) in defined subjects, and monitoring the correction of nutritional deficiency with a pure LC n-3 PUFA formulation in sufficient doses, while monitoring CVD risk factors are lacking. We tested the efficacy of a novel LC n-3 PUFA Medical Food formulation (VASCAZEN(), > 90 % pure with a 6:1 eicosapentaenoic acid-(EPA):docosahexaenoic acid-(DHA) ratio; 6:1-OM3), to correct such deficiency and determine the concomitant effects on lipid profiles. Of 655 subjects screened, 89 % were LC n-3 PUFA deficient (Omega-Score, (OS) = blood EPA + DHA + Docosapentaenoic acid < 6.1 %). From these, a study was conducted on 110 ambulatory cardiovascular subjects. Placebo: corn oil. Primary endpoint: change in OS. Secondary endpoint: changes in blood lipid profiles. At 8 weeks of treatment with 6:1-OM3 (4 g/day), placebo-adjusted median OS levels (n = 56) significantly improved (132 %, P < 0.0001) with a decrease in AA (arachidonic acid): EPA ratio (82 %, P < 0.0001). In hypertriglyceridemic subjects (TG 2.26-5.65 mmol/L), HDL-C improved (9 %, P = 0.0069), TG-reduced (48 %, P < 0.0001), and VLDL-C reduced (30 %, P = 0.0023), without significantly affecting LDL-C levels. This study confirms that LC n-3 PUFA deficiency is prevalent in the US population, and its correction with 6:1-OM3 in CVD subjects improves lipid profiles. The purity, EPA:DHA ratio and dose are determinant factors for optimal efficacy of a formulation in reducing CVD risk factors. PMID:25185754

  20. Thermoelectric power factors of nanocarbon ensembles as a function of temperature

    NASA Astrophysics Data System (ADS)

    Gruen, D. M.; Bruno, P.; Arenal, R.; Routbort, J.; Singh, D.; Xie, M.

    2009-04-01

    Thermoelectric power factors of nanocarbon ensembles have been determined as a function of temperature from 400 to 1200 K. The ensembles, composed of mixtures of nanographite or disperse ultrananocrystalline diamond with B4C, are formed into mechanically rigid compacts by reaction at 1200 K with methane gas and subsequently annealed in an argon atmosphere at temperatures up to 2500 K. The ensembles were characterized using scanning electron microscopy, Raman, x-ray diffraction, and high resolution transmission electron microscopy techniques and found to undergo profound nanostructural changes as a function of temperature while largely preserving their nanometer sizes. The power factors increase strongly both as a function of annealing temperature and of the temperature at which the measurements are carried out reaching 1 ?W/K2 cm at 1200 K without showing evidence of a plateau. Density functional "molecular analog" calculations on systems based on stacked graphene sheets show that boron substitutional doping results in a lowering of the Fermi level and the creation of a large number of hole states within thermal energies of the Fermi level [P. C. Redfern, D. M. Greun, and L. A. Curtiss, Chem. Phys. Lett. 471, 264 (2009)]. We propose that enhancement of electronic configurational entropy due to the large number of boron configurations in the graphite lattice contributes to the observed thermoelectric properties of the ensembles.

  1. Thermoelectric power factors of nanocarbon ensembles as a function of temperature.

    SciTech Connect

    Gruen, D. M.; Bruno, P.; Arenal, R.; Routbort, J.; Singh, D.; Xie, M.; CNRS-ONERA; Michigan Technological Univ.

    2009-01-01

    Thermoelectric power factors of nanocarbon ensembles have been determined as a function of temperature from 400 to 1200 K. The ensembles, composed of mixtures of nanographite or disperse ultrananocrystalline diamond with B{sub 4}C, are formed into mechanically rigid compacts by reaction at 1200 K with methane gas and subsequently annealed in an argon atmosphere at temperatures up to 2500 K. The ensembles were characterized using scanning electron microscopy, Raman, x-ray diffraction, and high resolution transmission electron microscopy techniques and found to undergo profound nanostructural changes as a function of temperature while largely preserving their nanometer sizes. The power factors increase strongly both as a function of annealing temperature and of the temperature at which the measurements are carried out reaching 1 {mu}W/K{sup 2} cm at 1200 K without showing evidence of a plateau. Density functional 'molecular analog' calculations on systems based on stacked graphene sheets show that boron substitutional doping results in a lowering of the Fermi level and the creation of a large number of hole states within thermal energies of the Fermi level [P. C. Redfern, D. M. Greun, and L. A. Curtiss, Chem. Phys. Lett. 471, 264 (2009)]. We propose that enhancement of electronic configurational entropy due to the large number of boron configurations in the graphite lattice contributes to the observed thermoelectric properties of the ensembles.

  2. Low-temperature-induced transcription factors in grapevine enhance cold tolerance in transgenic Arabidopsis plants.

    PubMed

    Takuhara, Yuki; Kobayashi, Masayuki; Suzuki, Shunji

    2011-06-15

    We report the characterization of low-temperature-induced transcription factors in grapevine (Vitis vinifera). Four transcription factors were identified in low-temperature-treated grapevine. The expression of V. vinifera C-repeat-binding factors, VvCBF2, VvCBF4, and VvCBFL, and V. vinifera B-box-type zinc finger protein, VvZFPL, was immediately induced and upregulated in leaves by the low-temperature treatment. Similar induction of the gene expression was observed in low-temperature-treated stems and flowers, although VvZFPL was constitutively expressed in flowers. Tendrils expressed all the four genes constitutively. In berry skin, VvCBF2 and VvCBFL were induced by the low-temperature treatment before the onset of vraison, while only VvCBF2 was induced under the low-temperature condition after the onset of vraison. The overexpression of VvCBF2 and VvZFPL in Arabidopsis plants led to longer hypocotyls than the control plants. The rosette leaves of these plants were smaller and had lower chlorophyll contents than those of the control plants, resulting in a pale green color. Finally, the VvCBF2- and VvZFPL-overexpressing plants revealed growth retardation. These results suggest that VvCBF2 and VvZFPL may affect photomorphogenesis and growth in grapevine. Meanwhile, no morphological changes were detected in the VvCBF4- and VvCBFL-overexpressing plants. The cold tolerance test demonstrated that all of the overexpressing plants remained viable and noticeably healthy compared with the control plants even after exposure to severe cold treatment, suggesting that VvCBF2, VvCBF4, VvCBFL, or VvZFPL may enhance cold tolerance in grapevine. PMID:21185622

  3. Conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation, 1945--1947. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Mart, E.I.; Denham, D.H.; Thiede, M.E.

    1993-12-01

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the U.S. Department of Energy`s (DOE) Hanford Site near Richland, Washington. The HEDR Project is conducted by Battelle, Pacific Northwest Laboratories (BNW). One of the radionuclides emitted that would affect the radiation dose was iodine-131. This report describes in detail the reconstructed conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation which was collected from the beginning of October 1945 through the end of December 1947.

  4. Arterial to end-tidal Pco2 difference during exercise in normoxia and severe acute hypoxia: importance of blood temperature correction

    PubMed Central

    Losa-Reyna, José; Torres-Peralta, Rafael; Henriquez, Juan José González; Calbet, José A L

    2015-01-01

    Negative arterial to end-tidal Pco2 differences ((a-ET)Pco2) have been reported in normoxia. To determine the influence of blood temperature on (a-ET)Pco2, 11 volunteers (21 ± 2 years) performed incremental exercise to exhaustion in normoxia (Nx, PIo2: 143 mmHg) and hypoxia (Hyp, PIo2: 73 mmHg), while arterial blood gases and temperature (ABT) were simultaneously measured together with end-tidal Pco2 (PETco2). After accounting for blood temperature, the (a-ET) Pco2 was reduced (in absolute values) from −4.2 ± 1.6 to −1.1 ± 1.5 mmHg in normoxia and from −1.7 ± 1.6 to 0.9 ± 0.9 mmHg in hypoxia (both P < 0.05). The temperature corrected (a-ET)Pco2 was linearly related with absolute and relative exercise intensity, VO2, VCO2, and respiratory rate (RR) in normoxia and hypoxia (R2: 0.52–0.59). Exercise CO2 production and PETco2 values were lower in hypoxia than normoxia, likely explaining the greater (less negative) (a-ET)Pco2 difference in hypoxia than normoxia (P < 0.05). At near-maximal exercise intensity the (a-ET)Pco2 lies close to 0 mmHg, that is, the mean Paco2 and the mean PETco2 are similar. The mean exercise (a-ET)Pco2 difference is closely related to the mean A-aDO2 difference (r = 0.90, P < 0.001), as would be expected if similar mechanisms perturb the gas exchange of O2 and CO2 during exercise. In summary, most of the negative (a-ET)Pco2 values observed in previous studies are due to lack of correction of Paco2 for blood temperature. The absolute magnitude of the (a-ET)Pco2 difference is lower during exercise in hypoxia than normoxia. PMID:26508736

  5. Arterial to end-tidal Pco2 difference during exercise in normoxia and severe acute hypoxia: importance of blood temperature correction.

    PubMed

    Losa-Reyna, Jos; Torres-Peralta, Rafael; Henriquez, Juan Jos Gonzlez; Calbet, Jos A L

    2015-10-01

    Negative arterial to end-tidal pco2 differences ((a-ET)pco2) have been reported in normoxia. To determine the influence of blood temperature on (a-ET)pco2, 11 volunteers (212years) performed incremental exercise to exhaustion in normoxia (Nx, Pio2: 143mmHg) and hypoxia (Hyp, Pio2: 73mmHg), while arterial blood gases and temperature (ABT) were simultaneously measured together with end-tidal pco2 (PE tco2). After accounting for blood temperature, the (a-ET) pco2 was reduced (in absolute values) from -4.21.6 to -1.11.5mmHg in normoxia and from -1.71.6 to 0.90.9mmHg in hypoxia (both P<0.05). The temperature corrected (a-ET)pco2 was linearly related with absolute and relative exercise intensity, VO2, VCO2, and respiratory rate (RR) in normoxia and hypoxia (R(2): 0.52-0.59). Exercise CO2 production and PE tco2 values were lower in hypoxia than normoxia, likely explaining the greater (less negative) (a-ET)pco2 difference in hypoxia than normoxia (P<0.05). At near-maximal exercise intensity the (a-ET)pco2 lies close to 0mmHg, that is, the mean Paco2 and the mean PE tco2 are similar. The mean exercise (a-ET)pco2 difference is closely related to the mean A-aDO2 difference (r=0.90, P<0.001), as would be expected if similar mechanisms perturb the gas exchange of O2 and CO2 during exercise. In summary, most of the negative (a-ET)pco2 values observed in previous studies are due to lack of correction of Paco2 for blood temperature. The absolute magnitude of the (a-ET)pco2 difference is lower during exercise in hypoxia than normoxia. PMID:26508736

  6. ECOC comparison exercise with identical thermal protocols after temperature offset correction - instrument diagnostics by in-depth evaluation of operational parameters

    NASA Astrophysics Data System (ADS)

    Panteliadis, P.; Hafkenscheid, T.; Cary, B.; Diapouli, E.; Fischer, A.; Favez, O.; Quincey, P.; Viana, M.; Hitzenberger, R.; Vecchi, R.; Saraga, D.; Sciare, J.; Jaffrezo, J. L.; John, A.; Schwarz, J.; Giannoni, M.; Novak, J.; Karanasiou, A.; Fermo, P.; Maenhaut, W.

    2015-02-01

    A comparison exercise on thermal-optical elemental carbon/organic carbon (ECOC) analysers was carried out among 17 European laboratories. Contrary to previous comparison exercises, the 17 participants made use of an identical instrument set-up, after correcting for temperature offsets with the application of a recently developed temperature calibration kit (Sunset Laboratory Inc, OR, US). Temperature offsets reported by participants ranged from -93 to +100 °C per temperature step. Five filter samples and two sucrose solutions were analysed with both the EUSAAR2 and NIOSH870 thermal protocols. z scores were calculated for total carbon (TC); nine outliers and three stragglers were identified. Three outliers and eight stragglers were found for EC. Overall, the participants provided results between the warning levels with the exception of two laboratories that showed poor performance, the causes of which were identified and corrected through the course of the comparison exercise. The TC repeatability and reproducibility (expressed as relative standard deviations) were 11 and 15% for EUSAAR2 and 9.2 and 12% for NIOSH870; the standard deviations for EC were 15 and 20% for EUSAAR2 and 20 and 26% for NIOSH870. TC was in good agreement between the two protocols, TCNIOSH870 = 0.98 × TCEUSAAR2 (R2 = 1.00, robust means). Transmittance (TOT) calculated EC for NIOSH870 was found to be 20% lower than for EUSAAR2, ECNIOSH870 = 0.80 × ECEUSAAR2 (R2 = 0.96, robust means). The thermograms and laser signal values were compared and similar peak patterns were observed per sample and protocol for most participants. Notable deviations from the typical patterns indicated either the absence or inaccurate application of the temperature calibration procedure and/or pre-oxidation during the inert phase of the analysis. Low or zero pyrolytic organic carbon (POC), as reported by a few participants, is suggested as an indicator of an instrument-specific pre-oxidation. A sample-specific pre-oxidation effect was observed for filter G, for all participants and both thermal protocols, indicating the presence of oxygen donors on the suspended particulate matter. POC (TOT) levels were lower for NIOSH870 than for EUSAAR2, which is related to the heating profile differences of the two thermal protocols.

  7. Correction of systematic model forcing bias of CLM using assimilation of cosmic-ray neutrons and land surface temperature: a study in the Heihe catchment, China

    NASA Astrophysics Data System (ADS)

    Han, X.; Hendricks Franssen, H.-J.; Rosolem, R.; Jin, R.; Li, X.; Vereecken, H.

    2014-07-01

    The recent development of the non-invasive cosmic-ray soil moisture sensing technique fills the gap between point scale soil moisture measurements and regional scale soil moisture measurements by remote sensing. A cosmic-ray probe measures soil moisture for a footprint with a diameter of ~600 m (at sea level) and with an effective measurement depth between 12 and 76 cm, depending on the soil humidity. In this study, it was tested whether neutron counts also allow to correct for a systematic error in the model forcings. Lack of water management data often cause systematic input errors to land surface models. Here, the assimilation procedure was tested for an irrigated corn field (Heihe Watershed Allied Telemetry Experimental Research - HiWATER, 2012) where no irrigation data were available as model input although the area a significant amount of water was irrigated. Measured cosmic-ray neutron counts and Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) products were jointly assimilated into the Community Land Model (CLM) with the Local Ensemble Transform Kalman Filter. Different data assimilation scenarios were evaluated, with assimilation of LST and/or cosmic-ray neutron counts, and possibly parameter estimation of leaf area index (LAI). The results show that the direct assimilation of cosmic-ray neutron counts can improve the soil moisture and evapotranspiration (ET) estimation significantly, correcting for lack of information on irrigation amounts. The joint assimilation of neutron counts and LST could improve further the ET estimation, but the information content of neutron counts exceeded the one of LST. Additional improvement was achieved by calibrating LAI, which after calibration was also closer to independent field measurements. It was concluded that assimilation of neutron counts was useful for ET and soil moisture estimation even if the model has a systematic bias like neglecting irrigation. However, also the assimilation of LST helped to correct the systematic model bias introduced by neglecting irrigation and LST could be used to update soil moisture with state augmentation.

  8. Real-time prediction of earthquake ground motion: time evolutional prediction using data assimilation and real-time correction of site amplification factors

    NASA Astrophysics Data System (ADS)

    Hoshiba, M.

    2012-12-01

    In this presentation, I propose a new approach for real-time prediction of seismic ground motion which is applicable to Earthquake Early Waning (EEW). Many methods of EEW are based on a network method in which hypocenter and magnitude (source parameters) are quickly determined (that is, interpretation of current wavefield), and then the ground motions are predicted, and warnings are issued depending on the strength of the predicted ground motion. In this method, though we can predict ground motions using a few parameters (location of hypocenter, magnitude, site factors) at any points, it is necessary to determine the hypocenter and magnitude at first, and error of the source parameters leads directly to the error of the prediction. It is not easy to take the effects of rupture directivity and source extent into account, and it is impossible to fully reproduce the current wavefield from the interpreted source parameters. In general, wave motion is predictable when boundary condition and initial condition are given. Time evolutional prediction is a method based on this approach using the current wavefield as an initial condition, that is u(x, t+?t)=H(u(x, t)), where u is the wave motion at location x at lapse time t, and H is the prediction operator. Future wave motion, u(x, t+?t), is predicted from the distribution of the current wave motion u(x, t) using H. For H, finite difference technique or boundary integral equation method, such as Kirchhoff integral, is used. In the time evolutional prediction, determination of detailed distribution of current wave motion is a key, so that dense seismic observation network is required. Data assimilation is a technique to produce artificially denser network, which is widely used for numerical weather prediction and oceanography. Distribution of current wave motion is estimated from not only the current real observation of u(x, t), but also the prediction of one step before, H(u(x, t-?t)). Combination of them produces denser artificial network than the real one. Data assimilation is a powerful technique for time evolutional prediction. In seismology and earthquake engineering, however, site amplification factors should be corrected beforehand for applying the data assimilation. A method is proposed in which the frequency dependent site factor can be corrected in real time. The site factor is represented by the causal filter in time domain which is estimated from bilinear transform and warping methods in digital filtering technique. Using the causal filter, the site amplification factor is corrected in real time manner. Instead of rapid estimation of hypocentral location and M, time evolutional prediction is a powerful method for real-time prediction of ground motion for EEW, which is applicable even for cases of strong rupture directivity and large source extent. Techniques of data assimilation and real time correction of site amplification factors will be applied for the time evolutional prediction. An example of the real time correction of site factors is presented using data from borehole seismometer (depth: 500m) in the Kanto region.

  9. Temperature is the key factor explaining interannual variability of Daphnia development in spring: a modelling study.

    PubMed

    Schalau, Kristine; Rinke, Karsten; Straile, Dietmar; Peeters, Frank

    2008-09-01

    Plankton succession during spring/early summer in temperate lakes is characterised by a highly predictable pattern: a phytoplankton bloom is grazed down by zooplankton (Daphnia) inducing a clear-water phase. This sequence of events is commonly understood as a cycle of consumer-resource dynamics, i.e. zooplankton growth is driven by food availability. Here we suggest, using a modelling study based on a size-structured Daphnia population model, that temperature and not food is the dominant factor driving interannual variability of Daphnia population dynamics during spring. Simply forcing this model with a seasonal temperature regime typical for temperate lakes is sufficient for generating the distinctive seasonal trajectory of Daphnia abundances observed in meso-eutrophic temperate lakes. According to a scenario analysis, a forward shift of the vernal temperature increase by 60 days will advance the timing of the Daphnia maximum on average by 54 days, while a forward shift in the start of the spring bloom by 60 days will advance the Daphnia maximum only by less than a third (17 days). Hence, the timing of temperature increase was more important for the timing of Daphnia development than the timing of the onset of algal growth. The effect of temperature is also large compared to the effect of applying different Daphnia mortality rates (0.055 or 0.1 day(-1), 38 days), an almost tenfold variation in phytoplankton carrying capacity (25 days) and a tenfold variation in Daphnia overwintering abundance (3 days). However, the standing stock of Daphnia at its peak was almost exclusively controlled by the phytoplankton carrying capacity of the habitat and seems to be essentially independent of temperature. Hence, whereas food availability determines the standing stock of Daphnia at its spring maximum, temperature appears to be the most important factor driving the timing of the Daphnia maximum and the clear-water phase in spring. PMID:18574598

  10. Should Quaternary sea-level changes be used to correct glacier ELAs, vegetation belt altitudes and sea level temperatures for inferring climate changes?

    NASA Astrophysics Data System (ADS)

    Osmaston, Henry A.

    2006-03-01

    Changes in the altitudes of glacier snowlines (ELAs) and the altitudes of montane vegetation belts (VBAs) measure Quaternary climatic change. An accepted 'correction' to such changes by deducting the amount of contemporary sea level fall is wrong, since the air displaced by the ice sheets approximately fills the space left by the falling sea level and so there is no overall downward movement of the troposphere. This also causes a reduced cooling at the lowered sea level relative to that at the former inter-glacial sea level, about 1C at the Las Glacial Maximum, which reduces the discrepancies previously noted by others between terrestrial and marine estimates of sea-level cooling. The change in temperature is indicated by the product of the ELA or VBA lowering and the environmental lapse rate (ELR). Prior estimates of ?ELA (-900 135 m) and ELR (-6 0.1C km -1) would indicate a cooling of -5.4C at interglacial sea level and -4.4C at glacial sea level, although glacial-period ELRs are not known reliably. Established ELA corrections for local epeirogenic uplift or subsidence are appropriate.

  11. MAIN-LIKE1 is a crucial factor for correct cell division and differentiation in Arabidopsis thaliana.

    PubMed

    hlken, Christine; Horvath, Beatrix; Stadler, Ruth; Sauer, Norbert; Weingartner, Magdalena

    2014-04-01

    Plant development requires accurate coordination of gene expression, both in actively dividing meristematic cells and differentiated cells. Cell fate establishment and maintenance, among others, are mediated by chromatin organization complexes that determine the stable transcriptional states of specific cell types. Here, we focus on MAIN-LIKE1 (MAIL1), one of three homologs of MAINTENANCE OF MERISTEMS (MAIN), which form a plant-specific gene family in Arabidopsis thaliana. We show that MAIL1 encodes a ubiquitously expressed nuclear protein. A mail1 loss-of-function mutant developed short primary roots, in which the meristematic cells accumulated DNA double-strand breaks and underwent massive cell death. In addition, mail1 mutant showed also cell differentiation defects in root and shoot tissues, and developed disorganized callus-like structures. The genetic interaction between main and mail1 mutants suggests that they act in the same pathway, and that both are essential for maintaining correct cell division acitivity in meristematic cells, while MAIL1 has an additional function in differentiating cells. PMID:24635680

  12. Temperature sensitivity of the cavity scale factor enhancement for a Gaussian absorption resonance

    NASA Astrophysics Data System (ADS)

    Myneni, Krishna; Smith, David D.; Chang, Hongrok; Luckay, H. A.

    2015-11-01

    We derive analytic expressions for the on-resonant cavity scale factor enhancement dependence on temperature, S0(T ) , for an intracavity medium with a Gaussian absorption resonance. Results are expressed as functions of the cavity parameters and the two resonance parameters: ?0(T ) , the peak absorption coefficient, and ??R(T ) , the resonance width. A semiempirical model is developed for the temperature-dependent absorption coefficient, ?F(? ,T ) , in an alkali-metal-atom vapor cell, and is used to compare the predicted behavior of ?0(T ) and ??R(T ) with the measured values for the D 2F =2 ?F' resonance in 87Rb, over the temperature range 298-325 K. Measurements of S0(T ) in a low-finesse ring cavity, using the same vapor cell as the intracavity dispersive medium, were performed and found to be in agreement with the temperature-dependent behavior predicted by our theory, with quantitative agreement to 2 K for the critical temperature. The practical range of S0 is found to be limited by the achievable temperature stability of the resonance parameters of the dispersive medium.

  13. SiC MOSFET Based Single Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications

    SciTech Connect

    Onar, Omer C; Tang, Lixin; Chinthavali, Madhu Sudhan; Campbell, Steven L; Miller , John M.

    2014-01-01

    Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges the utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance due to variable parameters such as battery state-of-charge, coupling factor, and coil misalignment. This paper presents the implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation. The proposed SiC MOSFET based single phase active front end rectifier with PFC resulted in >97% efficiency at 137mm air-gap and >95% efficiency at 160mm air-gap.

  14. Uptake of inorganic phosphate is a limiting factor for Saccharomyces cerevisiae during growth at low temperatures.

    PubMed

    Vicent, Isabel; Navarro, Alfonso; Mulet, Jose M; Sharma, Sukesh; Serrano, Ramn

    2015-05-01

    The fermenting ability of Saccharomyces at low temperatures is crucial for the development of alcoholic beverages, but the key factors for the cold tolerance of yeast are not well known. In this report, we present the results of a screening for genes able to confer cold tolerance by overexpression in a laboratory yeast strain auxotrophic for tryptophan. We identified genes of tryptophan permeases (TAT1 and TAT2), suggesting that the first limiting factor in the growth of tryptophan auxotrophic yeast at low temperatures is tryptophan uptake. This fact is of little relevance to industrial strains which are prototrophic for tryptophan. Then, we screened for genes able to confer growth at low temperatures in tryptophan-rich media and found several genes related to phosphate uptake (PHO84, PHO87, PHO90 and GTR1). This suggests that without tryptophan limitation, uptake of inorganic phosphate becomes the limiting factor. We have found that overexpression of the previously uncharacterized ORF YCR015c/CTO1 increases the uptake of inorganic phosphate. Also, genes involved in ergosterol biosynthesis (NSG2) cause improvement of growth at 10C, dependent on tryptophan uptake, while the gluconeogenesis gene PCK1 and the proline biosynthesis gene PRO2 cause an improvement in growth at 10C, independent of tryptophan and phosphate uptake. PMID:25725023

  15. Influence of thermochemical factors on the life of the lining of a high temperature reactor

    SciTech Connect

    Vasil'ev, V.I.; D'yakonova, L.A.; Gnedina, I.A.; Rozhdestvenskaya, T.L.

    1986-07-01

    For the purpose of development of measures directed toward increasing the life of the VTR-20, the lining failure mechanism was investigated with the use of microscopic, x-ray diffraction, and analytical chemiacl methods of analysis. It was concluded that the life of the periclase lining of a high-temperature reactor in the production of ferrochrome is determined by a combiantion of factors which includes the high process temperatures, intense interaction of the molten material in the lining, impregnation of the refractory primarily by oxides of silicon and calcium, active mass exchange in the occurence of exothermic reactions, temperature variations in the working layer related to the periodic character of service of the reactor, and the presence of joints in the lining. Maintenence on the reactor lining of an ore-slag layer increases the reactor life by 25-50%.

  16. Correction factors for the ISO rod phantom, a cylinder phantom, and the ICRU sphere for reference beta radiation fields of the BSS 2

    NASA Astrophysics Data System (ADS)

    Behrens, R.

    2015-03-01

    The International Organization for Standardization (ISO) requires in its standard ISO 6980 that beta reference radiation fields for radiation protection be calibrated in terms of absorbed dose to tissue at a depth of 0.07 mm in a slab phantom (30 cm x 30 cm x 15 cm). However, many beta dosemeters are ring dosemeters and are, therefore, irradiated on a rod phantom (1.9 cm in diameter and 30 cm long), or they are eye dosemeters possibly irradiated on a cylinder phantom (20 cm in diameter and 20 cm high), or area dosemeters irradiated free in air with the conventional quantity value (true value) being defined in a sphere (30 cm in diameter, made of ICRU tissue (International Commission on Radiation Units and Measurements)). Therefore, the correction factors for the conventional quantity value in the rod, the cylinder, and the sphere instead of the slab (all made of ICRU tissue) were calculated for the radiation fields of 147Pm, 85Kr, 90Sr/90Y, and, 106Ru/106Rh sources of the beta secondary standard BSS 2 developed at PTB. All correction factors were calculated for 0° up to 75° (in steps of 15°) radiation incidence. The results are ready for implementation in ISO 6980-3 and have recently been (partly) implemented in the software of the BSS 2.

  17. Possible factors controlling global marine temperature variations over the past century

    SciTech Connect

    Zhongxiang, Wu; Newell, R.E.; Hsiung, J. )

    1990-07-20

    Data from the Global Ocean Surface Temperature Atlas (GOSTA), which includes 60 million ship reports for the 1856-1988 period, have been used to study global night marine air temperature (MAT) and sea surface temperature (SST) interannual variations. Linear regression has been used to establish trends over two periods: 1888-1988, a period often used for land station analyses, and 1856-1988. For global MAT the trends for the century beginning in 1888 computed for these periods are 0.49C and 0.29C, respectively. Stepwise linear regression is used to relate the marine time series to three physical variables thought to influence surface temperatures, namely, changes in solar radiation output, changes in atmospheric transmission for solar radiation, and changes in the global surface pressure field. Indices of these variables used are new computations of solar irradiance, atmospheric turbidity at Sonnblick, Austria, supported by sunshine records from Japan, and the Southern Oscillation Index (SOI). When MAT and SST series are examined for the globe, northern and southern hemisphere separately, the largest fraction of the variance (45% for the global MAT, 35% for global SST) is accounted for by turbidity changes, while the tropical east Pacific shows the largest fraction (45% for MAT, 49% for SST) associated with SOI changes. Modeled solar irradiance variations contribute the second most important factor in controlling marine temperature fluctuations in the southern hemisphere. The tropical west Pacific SST is relatively insensitive to the three parameters, in accordance with previous suggestions that the temperature there is limited by evaporation. When the residuals are examined after account is taken of these factors, the global MAT trend for 1888-1988 is reduced to 0.24{degree}C.

  18. Functional adaptations of the bacterial chaperone trigger factor to extreme environmental temperatures.

    PubMed

    Godin-Roulling, Amandine; Schmidpeter, Philipp A M; Schmid, Franz X; Feller, Georges

    2015-07-01

    Trigger factor (TF) is the first molecular chaperone interacting cotranslationally with virtually all nascent polypeptides synthesized by the ribosome in bacteria. Thermal adaptation of chaperone function was investigated in TFs from the Antarctic psychrophile Pseudoalteromonas haloplanktis, the mesophile Escherichia coli and the hyperthermophile Thermotoga maritima. This series covers nearly all temperatures encountered by bacteria. Although structurally homologous, these TFs display strikingly distinct properties that are related to the bacterial environmental temperature. The hyperthermophilic TF strongly binds model proteins during their folding and protects them from heat-induced misfolding and aggregation. It decreases the folding rate and counteracts the fast folding rate imposed by high temperature. It also functions as a carrier of partially folded proteins for delivery to downstream chaperones ensuring final maturation. By contrast, the psychrophilic TF displays weak chaperone activities, showing that these functions are less important in cold conditions because protein folding, misfolding and aggregation are slowed down at low temperature. It efficiently catalyses prolyl isomerization at low temperature as a result of its increased cellular concentration rather than from an improved activity. Some chaperone properties of the mesophilic TF possibly reflect its function as a cold shock protein in E. coli. PMID:25389111

  19. ECOC comparison exercise with identical thermal protocols after temperature offsets correction - instrument diagnostics by in-depth evaluation of operational parameters

    NASA Astrophysics Data System (ADS)

    Panteliadis, P.; Hafkenscheid, T.; Cary, B.; Diapouli, E.; Fischer, A.; Favez, O.; Quincey, P.; Viana, M.; Hitzenberger, R.; Vecchi, R.; Maggos, T.; Sciare, J.; Jaffrezo, J. L.; John, A.; Schwarz, J.; Giannoni, M.; Novak, J.; Karanasiou, A.; Fermo, P.; Maenhaut, W.

    2014-08-01

    A comparison exercise on thermal-optical elemental carbon/organic carbon (ECOC) analyzers was carried out among 17 European laboratories. Contrary to previous comparison exercises, the 17 participants made use of an identical instrument set-up, after correcting for temperature offsets with the application of a recently developed temperature calibration kit (Sunset Laboratory Inc, OR, US). Five filter samples and two sucrose solutions were analyzed with both the EUSAAR2 and NIOSH870 thermal protocols. z Scores were calculated for total carbon (TC) and nine outliers and three stragglers were identified. Three outliers and eight stragglers were found for EC. Overall, the participants provided results within the warning levels with the exception of two laboratories that showed poor performance, the causes of which were identified and corrected through the course of the comparison exercise. The TC repeatability and reproducibility relative standard deviations were 11.4 and 14.6% for EUSAAR2 and 9.2 and 11.7% for NIOSH870; the standard deviations for EC were 15.3 and 19.5% for EUSAAR2 and 19.9 and 25.5% for NIOSH870. TC was in good agreement between the two protocols, TCNIOSH870 = 0.98 · TCEUSAAR2 (R2 = 1.00, normalized means). Transmittance (TOT) calculated EC for NIOSH870 was found to be 20% lower than for EUSAAR2, ECNIOSH870 = 0.80 · ECEUSAAR2 (R2 = 0.96, normalized means). The thermograms and laser signal values were compared and similar peak patterns were observed per sample and protocol for most participants. Notable deviations of plotted values indicated absence or inaccurate application of the temperature calibration procedure and/or pre-oxidation during the inert phase of the analysis. Low or no pyrolytic organic carbon (POC), as reported by a few participants, is suggested as an indicator of pre-oxidation. A sample-specific pre-oxidation effect was observed for filter G, for all participants and both thermal protocols, indicating the presence of oxygen donors on the suspended particulate matter. POC (TOT) levels were lower for NIOSH870 than for EUSAAR2, which is related to the heating profile differences of the two thermal protocols.

  20. Sustained phenotypic correction of hemophilia a mice following oncoretroviral-mediated expression of a bioengineered human factor VIII gene in long-term hematopoietic repopulating cells.

    PubMed

    Moayeri, Morvarid; Ramezani, Ali; Morgan, Richard A; Hawley, Teresa S; Hawley, Robert G

    2004-11-01

    Hematopoietic stem cells (HSCs) are an attractive target cell population for hemophilia A gene therapy because of their capacity to regenerate the hematolymphoid system permanently following transplantation. Here we transplanted bone marrow (BM) cells transduced with a splicing-optimized MSCV oncoretroviral vector expressing a secretion-improved human factor VIII gene into immunocompromised hemophilic mice that had received a reduced dose conditioning regimen. An enhanced green fluorescent protein (EGFP) reporter gene linked to an encephalomyocarditis virus internal ribosome entry site was incorporated into the vector to allow preselection of transduced cells and facile evaluation of engraftment. Sustained expression of EGFP was demonstrated in the peripheral blood, and therapeutic levels of factor VIII were detected in the plasma of the majority of the recipients for the duration of the observation period (up to 22 weeks). Coordinate expression of factor VIII and EGFP (up to 19 weeks) was transferred to secondary BM transplant recipients, indicating that long-term repopulating HSCs had been successfully gene modified. Notably, the hemophilic phenotype of all treated mice was corrected, thus demonstrating the potential of HSC-directed oncoretroviral-mediated factor VIII gene transfer as a curative therapeutic strategy for hemophilia A. PMID:15509507

  1. Spatial downscaling and correction of precipitation and temperature time series to high resolution hydrological response units in the Canadian Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Kienzle, Stefan

    2015-04-01

    Precipitation is the central driving force of most hydrological processes, and is also the most variable element of the hydrological cycle. As the precipitation to runoff ratio is non-linear, errors in precipitation estimations are amplified in streamflow simulations. Therefore, the accurate estimate of areal precipitation is essential for watershed models and relevant impacts studies. A procedure is presented to demonstrate the spatial distribution of daily precipitation and temperature estimates across the Rocky Mountains within the framework of the ACRU agro-hydrological modelling system (ACRU). ACRU (Schulze, 1995) is a physical-conceptual, semi-distributed hydrological modelling system designed to be responsive to changes in land use and climate. The model has been updated to include specific high-mountain and cold climate routines and is applied to simulate impacts of land cover and climate change on the hydrological behaviour of numerous Rocky Mountain watersheds in Alberta, Canada. Both air temperature and precipitation time series need to be downscaled to hydrological response units (HRUs), as they are the spatial modelling units for the model. The estimation of accurate daily air temperatures is critical for the separation of rain and snow. The precipitation estimation procedure integrates a spatially distributed daily precipitation database for the period 1950 to 2010 at a scale of 10 by 10 km with a 1971-2000 climate normal database available at 2 by 2 km (PRISM). Resulting daily precipitation time series are further downscaled to the spatial resolution of hydrological response units, defined by 100 m elevation bands, land cover, and solar radiation, which have an average size of about 15 km2. As snow measurements are known to have a potential under-catch of up to 40%, further adjustment of snowfall may need to be increased using a procedure by Richter (1995). Finally, precipitation input to HRUs with slopes steeper than 10% need to be further corrected, because the true, sloped area, has a larger area than the planimetric area derived from a GIS. The omission of correcting for sloped areas would result in incorrect calculations of interception volumes, soil moisture storages, groundwater recharge rates, actual evapotranspiration volumes, and runoff coefficients. Daily minimum and maximum air temperatures are estimated for each HRU by downscaling the 10km time series to the HRUs by (a) applying monthly mean lapse rates, estimated either from surrounding climate stations or from the PRISM climate normal dataset in combination with a digital elevation model, (b) adjusting further for aspect of the HRU based on monthly mean incoming solar radiation, and (c) adjusting for canopy cover using the monthly mean leaf area indices. Precipitation estimates can be verified using independent snow water equivalent measurements derived from snow pillow or snow course observations, while temperature estimates are verified against either independent temperature measurements from climate stations, or from fire observation towers.

  2. [Temperature characteristics of huang-Ryes factor of all-trans-beta-carotene].

    PubMed

    Li, Shuo; Sun, Shang; Li, Zuo-wei; Qu, Guan-nan; Liu, Tian-yuan; Sun, Cheng-lin; Fan, Li-mei

    2013-09-01

    A visible absorption and Raman spectra of all-trans-beta-beta-carotene was measured in cyclohexanol solution in the temperature range from 68 degrees C to 26 degrees C. The results indicated that the visible absorption spectra are red-shifted, Raman scattering cross section increases, Huang-Ryes factor and electron-phonon coupling constants of CC bond vibration modes decreases with the temperature decreasing. The changes are interpreted using the theory of "coherent weakly damped electronic-lattice vibration model" and "effective conjugation length model". The red shift of the absorption spectra and intensity of the Raman active are attributed to the thermal conformational change-induced increase in the effective conjugation length in all-trans-beta-carotene chains. All-trans-beta-carotene has strong coherent weakly damped CC bonds vibrational properties, which lead to large Raman scattering cross section in the solvent of low temperature. The electron-phonon coupling constants with dimension are used, which can easily establish relation with the Huang-Rhys factor and calculate the electron-phonon coupling constants of CC bond vibration modes. Effective conjugation length, the pi-electron delocalization range and the Raman scattering cross section are described by the electron-phonon coupling constants. PMID:24371847

  3. Toward accurate thermochemistry of the (24)MgH, (25)MgH, and (26)MgH molecules at elevated temperatures: corrections due to unbound states.

    PubMed

    Szidarovszky, Tams; Csszr, Attila G

    2015-01-01

    The total partition functions QT and their first two moments Q(')T and Q(?)T, together with the isobaric heat capacities CpT, are computed a priori for three major MgH isotopologues on the temperature range of T = 100-3000 K using the recent highly accurate potential energy curve, spin-rotation, and non-adiabatic correction functions of Henderson et al. [J. Phys. Chem. A 117, 13373 (2013)]. Nuclear motion computations are carried out on the ground electronic state to determine the (ro)vibrational energy levels and the scattering phase shifts. The effect of resonance states is found to be significant above about 1000 K and it increases with temperature. Even very short-lived states, due to their relatively large number, have significant contributions to QT at elevated temperatures. The contribution of scattering states is around one fourth of that of resonance states but opposite in sign. Uncertainty estimates are given for the possible error sources, suggesting that all computed thermochemical properties have an accuracy better than 0.005% up to 1200 K. Between 1200 and 2500 K, the uncertainties can rise to around 0.1%, while between 2500 K and 3000 K, a further increase to 0.5% might be observed for Q(?)T and CpT, principally due to the neglect of excited electronic states. The accurate thermochemical data determined are presented in the supplementary material for the three isotopologues of (24)MgH, (25)MgH, and (26)MgH at 1 K increments. These data, which differ significantly from older standard data, should prove useful for astronomical models incorporating thermodynamic properties of these species. PMID:25573549

  4. Transcriptome-wide identification of Camellia sinensis WRKY transcription factors in response to temperature stress.

    PubMed

    Wu, Zhi-Jun; Li, Xing-Hui; Liu, Zhi-Wei; Li, Hui; Wang, Yong-Xin; Zhuang, Jing

    2016-02-01

    Tea plant [Camellia sinensis (L.) O. Kuntze] is a leaf-type healthy non-alcoholic beverage crop, which has been widely introduced worldwide. Tea is rich in various secondary metabolites, which are important for human health. However, varied climate and complex geography have posed challenges for tea plant survival. The WRKY gene family in plants is a large transcription factor family that is involved in biological processes related to stress defenses, development, and metabolite synthesis. Therefore, identification and analysis of WRKY family transcription factors in tea plant have a profound significance. In the present study, 50 putative C. sinensis WRKY proteins (CsWRKYs) with complete WRKY domain were identified and divided into three Groups (Group I-III) on the basis of phylogenetic analysis results. The distribution of WRKY family transcription factors among plantae, fungi, and protozoa showed that the number of WRKY genes increased in higher plant, whereas the number of these genes did not correspond to the evolutionary relationships of different species. Structural feature and annotation analysis results showed that CsWRKY proteins contained WRKYGQK/WRKYGKK domains and C2H2/C2HC-type zinc-finger structure: D-X18-R-X1-Y-X2-C-X4-7-C-X23-H motif; CsWRKY proteins may be associated with the biological processes of abiotic and biotic stresses, tissue development, and hormone and secondary metabolite biosynthesis. Temperature stresses suggested that the candidate CsWRKY genes were involved in responses to extreme temperatures. The current study established an extensive overview of the WRKY family transcription factors in tea plant. This study also provided a global survey of CsWRKY transcription factors and a foundation of future functional identification and molecular breeding. PMID:26308611

  5. Safety and Efficacy of Growth Factor Concentrate in the Treatment of Nasolabial Fold Correction: Split Face Pilot Study

    PubMed Central

    Sevilla, Gema P; Dhurat, Rachita S; Shetty, Geetanjali; Kadam, Prashant P; Totey, Satish M

    2015-01-01

    Background: Growth factors have long been known as an effective treatment for facial wrinkles. We developed growth factor concentrate (GFC) from the platelets and evaluated their clinical outcome in nasolabial folds. Aims and Objectives: We evaluated safety and efficacy of autologous GFC on patients with nasolabial folds. Materials and Methods: Study was conducted on 80 patients for nasolabial folds in two groups. Group I (20) received bilateral single injection of GFC and group II (60) received single injection of GFC on the right side of the face and platelet-rich plasma (PRP) on the left side of the face. Severity of nasolabial folds was determined at the baseline and 3 months of follow-up visits based on wrinkle severity rating scale (WSRS), Global aesthetic improvement scale (GAIS) and atlas photographic grading at rest and at full smile. Objective clinical assessment and subjective satisfaction scale was determined for overall improvement at the end of the study. Results: In group I, 2 subjects showed improvement after GFC treatment with the score of 3.1–4 (76–100%), 3 subjects with the score of 2.1–3 (51–75%), 14 with the score of 1.1–2 (26–50%) and 1 subject with the score of 0–1 (<25%) at the end of study. In group II, 51 subjects were evaluated at the end of study where, 34 (66%) showed superior improvements after GFC, 6 (11%) patients showed similar improvement on both side of the face, 10 (19.6%) patients showed no noticeable improvement on the either side of the face and only 1 patient (1.96%) showed superior improvement for PRP at the end of the study. Overall improvement score analysis showed that GFC was significantly superior to PRP (P < 0.001). Conclusion: Present study is a strong evidence to support the use of GFC for nasolabial folds. The results showed that the single application of GFC is highly effective and safe. PMID:26538718

  6. Small fields output factors measurements and correction factors determination for several detectors for a CyberKnife{sup Registered-Sign} and linear accelerators equipped with microMLC and circular cones

    SciTech Connect

    Bassinet, C.; Huet, C.; Derreumaux, S.; Baumann, M.; Trompier, F.; Roch, P.; Clairand, I.; Brunet, G.; Gaudaire-Josset, S.; Chea, M.; Boisserie, G.

    2013-07-15

    Purpose: The use of small photon fields is now an established practice in stereotactic radiosurgery and radiotherapy. However, due to a lack of lateral electron equilibrium and high dose gradients, it is difficult to accurately measure the dosimetric quantities required for the commissioning of such systems. Moreover, there is still no metrological dosimetric reference for this kind of beam today. In this context, the first objective of this work was to determine and to compare small fields output factors (OF) measured with different types of active detectors and passive dosimeters for three types of facilities: a CyberKnife{sup Registered-Sign} system, a dedicated medical linear accelerator (Novalis) equipped with m3 microMLC and circular cones, and an adaptive medical linear accelerator (Clinac 2100) equipped with an additional m3 microMLC. The second one was to determine the k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}} correction factors introduced in a recently proposed small field dosimetry formalism for different active detectors.Methods: Small field sizes were defined either by microMLC down to 6 Multiplication-Sign 6 mm{sup 2} or by circular cones down to 4 mm in diameter. OF measurements were performed with several commercially available active detectors dedicated to measurements in small fields (high resolution diodes: IBA SFD, Sun Nuclear EDGE, PTW 60016, PTW 60017; ionizing chambers: PTW 31014 PinPoint chamber, PTW 31018 microLion liquid chamber, and PTW 60003 natural diamond). Two types of passive dosimeters were used: LiF microcubes and EBT2 radiochromic films.Results: Significant differences between the results obtained by several dosimetric systems were observed, particularly for the smallest field size for which the difference in the measured OF reaches more than 20%. For passive dosimeters, an excellent agreement was observed (better than 2%) between EBT2 and LiF microcubes for all OF measurements. Moreover, it has been shown that these passive dosimeters do not require correction factors and can then be used as reference dosimeters. Correction factors for the active detectors have then been determined from the mean experimental OF measured by the passive dosimeters.Conclusions: Four sets of correction factors needed to apply the new small field dosimetry formalism are provided for several active detectors. A protocol for small photon beams OF determination based on passive dosimeters measurements has been recently proposed to French radiotherapy treatment centers.

  7. Correction of systematic model forcing bias of CLM using assimilation of cosmic-ray Neutrons and land surface temperature: a study in the Heihe Catchment, China

    NASA Astrophysics Data System (ADS)

    Han, X.; Franssen, H.-J. H.; Rosolem, R.; Jin, R.; Li, X.; Vereecken, H.

    2015-01-01

    The recent development of the non-invasive cosmic-ray soil moisture sensing technique fills the gap between point-scale soil moisture measurements and regional-scale soil moisture measurements by remote sensing. A cosmic-ray probe measures soil moisture for a footprint with a diameter of ~ 600 m (at sea level) and with an effective measurement depth between 12 and 76 cm, depending on the soil humidity. In this study, it was tested whether neutron counts also allow correcting for a systematic error in the model forcings. A lack of water management data often causes systematic input errors to land surface models. Here, the assimilation procedure was tested for an irrigated corn field (Heihe Watershed Allied Telemetry Experimental Research - HiWATER, 2012) where no irrigation data were available as model input although for the area a significant amount of water was irrigated. In the study, the measured cosmic-ray neutron counts and Moderate-Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) products were jointly assimilated into the Community Land Model (CLM) with the local ensemble transform Kalman filter. Different data assimilation scenarios were evaluated, with assimilation of LST and/or cosmic-ray neutron counts, and possibly parameter estimation of leaf area index (LAI). The results show that the direct assimilation of cosmic-ray neutron counts can improve the soil moisture and evapotranspiration (ET) estimation significantly, correcting for lack of information on irrigation amounts. The joint assimilation of neutron counts and LST could improve further the ET estimation, but the information content of neutron counts exceeded the one of LST. Additional improvement was achieved by calibrating LAI, which after calibration was also closer to independent field measurements. It was concluded that assimilation of neutron counts was useful for ET and soil moisture estimation even if the model has a systematic bias like neglecting irrigation. However, also the assimilation of LST helped to correct the systematic model bias introduced by neglecting irrigation and LST could be used to update soil moisture with state augmentation.

  8. Major complications and risk factors associated with surgical correction of congenital medial patellar luxation in 124 dogs.

    PubMed

    Cashmore, R G; Havlicek, M; Perkins, N R; James, D R; Fearnside, S M; Marchevsky, A M; Black, A P

    2014-01-01

    Dogs treated for congenital medial patellar luxation were reviewed for the purpose of determining the incidence of postoperative major complications requiring surgical revision and the risk factors for their occurrence. Major complications occurred in 18.5% of the patellar luxation stabilization procedures with implant associated complications being the most frequent, patellar reluxation the second, and tibial tuberosity avulsion the third most common major complication. Other complications included patellar ligament rupture and trochlear wedge displacement. When recession trochleoplasty was performed in addition to tibial tuberosity transposition, a 5.1-fold reduction in the rate of patellar reluxation was observed. Release of the cranial belly of the sartorius muscle further reduced the incidence of patellar reluxation, while patella alta (pre- or postoperative) and patellar luxation grade were not found to influence the rate of reluxation. Tibial tuberosity avulsion was 11.1-times more likely when using a single Kirschner wire to stabilize a transposition, compared with two Kirschner wires. Independent to the number of Kirschner wires used, the more caudodistally the Kirschner wires were directed, the higher the risk for tibial tuberosity avulsion. Tension bands were used in 24.4% of the transpositions with no tuberosity avulsion occurring in stifles stabilized with a tension band. Overall, grade 1 luxations had a significantly lower incidence of major complications than other grades, while body weight, age, sex, and bilateral patellar stabilization were not associated with risk of major complication development. PMID:24817090

  9. Factor Study for the Separator Plate of Mcfc Having Uniform Stiffness at Elevated Temperature

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Wook; Kim, Jung-Hyun; Jun, Joong-Hwan

    A molten carbonate fuel cell (MCFC) is composed of several stacks of unit cells. A unit cell is composed of two electrodes and a matrix that is inserted between separator plates. Separator plates should properly contact the electrodes to reduce the electricity loss arising from contact resistance. To this end, a pressure of about 2 kgf/cm2 is usually applied on the top of the stack, which results in the separator plates being somewhat compacted. Furthermore, the stiffness of the separator plates becomes degraded at elevated temperatures due to softening of the plate materials. Therefore, a nonuniform temperature distribution across the separator plates induced by exothermic reactions of the oxidant and reactant gases leads to a non-uniform plate stiffness. This study has firstly evaluated the change in separator plate stiffness as temperature changes by applying pressure to the plates. Secondly, using the Taguchi method, several design factors that affect stiffness have been investigated to determine which has the most influence. Based on these results, a new design for the separators, which allows for uniform stiffness at elevated temperatures, has been proposed.

  10. Systemic delivery of an adenoviral vector encoding canine factor VIII results in short-term phenotypic correction, inhibitor development, and biphasic liver toxicity in hemophilia A dogs.

    PubMed

    Gallo-Penn, A M; Shirley, P S; Andrews, J L; Tinlin, S; Webster, S; Cameron, C; Hough, C; Notley, C; Lillicrap, D; Kaleko, M; Connelly, S

    2001-01-01

    Canine hemophilia A closely mimics the human disease and has been used previously in the development of factor VIII (FVIII) protein replacement products. FVIII-deficient dogs were studied to evaluate an in vivo gene therapy approach using an E1/E2a/E3-deficient adenoviral vector encoding canine FVIII. Results demonstrated a high level of expression of the canine protein and complete phenotypic correction of the coagulation defect in all 4 treated animals. However, FVIII expression was short-term, lasting 5 to 10 days following vector infusion. All 4 dogs displayed a biphasic liver toxicity, a transient drop in platelets, and development of anticanine FVIII antibody. Canine FVIII inhibitor development was transient in 2 of the 4 treated animals. These data demonstrate that systemic delivery of attenuated adenoviral vectors resulted in liver toxicity and hematologic changes. Therefore, the development of further attenuated adenoviral vectors encoding canine FVIII will be required to improve vector safety and reduce the risk of immunologic sequelae, and may allow achievement of sustained phenotypic correction of canine hemophilia A. PMID:11133749

  11. Evaluation of Wall Correction Factor of INER's Air-Kerma Primary Standard Chamber and Dose Variation by Source Displacement for HDR 192Ir Brachytherapy

    PubMed Central

    Lee, J. H.; Wang, J. N.; Huang, T. T.; Su, S. H.; Chang, B. J.; Su, C. H.; Hsu, S. M.

    2013-01-01

    The aim of the present study was to estimate the wall effect of the self-made spherical graphite-walled cavity chamber with the Monte Carlo method for establishing the air-kerma primary standard of high-dose-rate (HDR) 192Ir brachytherapy sources at the Institute of Nuclear Energy Research (INER, Taiwan). The Monte Carlo method established in this paper was also employed to respectively simulate wall correction factors of the 192Ir air-kerma standard chambers used at the National Institute of Standards and Technology (NIST, USA) and the National Physical Laboratory (NPL, UK) for comparisons and verification. The chamber wall correction calculation results will be incorporated into INER's HDR 192Ir primary standard in the future. For the brachytherapy treatment in the esophagus or in the bronchi, the position of the isotope may have displacement in the cavity. Thus the delivered dose would differ from the prescribed dose in the treatment plan. We also tried assessing dose distribution due to the position displacement of HDR 192Ir brachytherapy source in a phantom with a central cavity by the Monte Carlo method. The calculated results could offer a clinical reference for the brachytherapy within the human organs with cavity. PMID:24222907

  12. Exposure levels due to WLAN devices in indoor environments corrected by a time-amplitude factor of distribution of the quasi-stochastic signals.

    PubMed

    Miclaus, Simona; Bechet, Paul; Stratakis, Dimitrios

    2014-12-01

    With the development of radiofrequency technology, radiating quasi-stochastic signals like the wireless local area networks (WLAN), a proper procedure of exposure level assessment is needed. No standardised procedure exists at the moment. While channel power measurement proved to overestimate the field strength, weighting techniques were proposed. The paper compares the exposure levels determined by three different procedures, two of them correcting the field level by weighting. Twenty-three experimental cases of WLAN traffic load are analysed in an indoor environment in controlled conditions. The results show the differences obtained when the duty cycle (DC) method is applied comparatively with the application of weighting based on an amplitude-time correction. Significant exposure level reductions of 52.6-79.2 % from the field determined by frequency domain method and of 36.5-72.8 % from the field determined by the DC weighting method were obtained by time-amplitude method. Specificities of weighting factors probability density functions were investigated and regression analysis was applied for a detailed characterisation of this procedure. PMID:24591729

  13. Factor IX ectopically expressed in platelets can be stored in alpha-granules and corrects the phenotype of hemophilia B mice.

    PubMed

    Zhang, Guowei; Shi, Qizhen; Fahs, Scot A; Kuether, Erin L; Walsh, Christopher E; Montgomery, Robert R

    2010-08-26

    We developed 2bF9 transgenic mice in a hemophilia B mouse model with the expression of human factor IX (FIX) under control of the platelet-specific integrin alphaIIb promoter, to determine whether ectopically expressing FIX in megakaryocytes can enable the storage of FIX in platelet alpha-granules and corrects the murine hemophilia B phenotype. FIX was detected in the platelets and plasma of 2bF9 transgenic mice by both antigen and activity assays. Approximately 90% of total FIX in blood was stored in platelets, most of which is releasable on activation of platelets. Immunostaining demonstrated that FIX was expressed in platelets and megakaryocytes and stored in alpha-granules. All 2bF9 transgenic mice survived tail clipping, suggesting that platelet-derived FIX normalizes hemostasis in the hemophilia B mouse model. This protection can be transferred by bone marrow transplantation or platelet transfusion. However, unlike our experience with platelet FVIII, the efficacy of platelet-derived FIX was limited in the presence of anti-FIX inhibitory antibodies. These results demonstrate that releasable FIX can be expressed and stored in platelet alpha-granules and that platelet-derived FIX can correct the bleeding phenotype in hemophilia B mice. Our studies suggest that targeting FIX expression to platelets could be a new gene therapy strategy for hemophilia B. PMID:20445020

  14. Finite element analysis of the penetration depth/tip radius ratio dependence on the correction factor ? in instrumented indentation of elastic-plastic materials

    NASA Astrophysics Data System (ADS)

    Abbes, F.; Troyon, M.; Meza, J. M.; Potiron, S.

    2010-06-01

    Measurements of mechanical properties by instrumented indentation rely heavily upon the relationship between the unloading contact stiffness, Su, the projected contact area, Ac, and the reduced modulus, Er. This relationship is written in the form Su = 2?Er(Ac/?)1/2, where ? is a correction factor that depends on the material properties, the geometry of the indenter and also the penetration depth. Most of the time a constant value of ? is used in experimental measurements, either 1.0 or a value around 1.05, which is not correct since ? strongly depends on the penetration depth as demonstrated by finite element calculations (FEC) on purely elastic materials and also experimentally on the fused quartz, which is the usual sample used for calibration of the contact area function. Here, the dependence of ? on the penetration depth and tip blunting is studied by FEC in the case of elastic-plastic materials generally encountered in engineering. The consequence of not taking into account the influence of ? on hardness and elastic modulus measurements is also investigated.

  15. Performance analysis and determination of the p(wall) correction factor for 60Co gamma-ray beams for Wellhfer Roos-type plane-parallel chambers.

    PubMed

    Palm, Asa; Czap, Ladislav; Andreo, Pedro; Mattsson, Olof

    2002-02-21

    The wall perturbation correction factor p(wall) in 60Co for Wellhfer Roos-type plane-parallel ionization chambers is determined experimentally and compared with the results of a previous study using PTW-Roos chambers (Palm et al 2000 Phys. Med. Biol. 45 971-81). Five ionization chambers of the type Wellhfer PPC-35 (or its equivalent PPC-40) are used for the analysis. Wall perturbation correction factors are obtained by assuming N(D,air) chamber factors determined by cross-calibration in a high-energy electron and in a 60Co gamma-ray beam to be equal, and by assigning any differences to the wall perturbation factor. The procedure yields a p(wall) value of 1.018 (u(c) = 0.010), which is slightly higher than the value 1.014 (u(c) = 0.010) formerly obtained for the PTW-Roos chambers using the N(D,air) method. The chamber-to-chamber variation in p(wall) for the Wellhfer-Roos chambers is found to be very small, with a maximum difference of 0.3%. The effect of using new p(cav) values for graphite-walled Farmer-type chambers used in water in electron beams is to decrease p(wall) by approximately 0.5%. The long- and short-term stability of the Roos-type chambers manufactured by Wellhfer is investigated by measurements at the IAEA Dosimetry Laboratory in Vienna, Austria, and at the Sahlgrenska University Hospital in Gteborg, Sweden. Calibrations made at the IAEA over several months show variations in the N(D,w) calibration factors larger than expected. based on previous experiences with PTW-Roos chambers. Measurements of the short-term stability of the Wellhfer-Roos chambers show a marked increase in chamber response for the time the chambers are immersed in water, pointing to a possible problem in the chamber design. As a consequence of these findings, Wellhfer is currently working on a re-design of the chamber to solve the stability problem. PMID:11900195

  16. Performance analysis and determination of the pwall correction factor for 60Co ?-ray beams for Wellhfer Roos-type plane-parallel chambers

    NASA Astrophysics Data System (ADS)

    Palm, sa; Czap, Ladislav; Andreo, Pedro; Mattsson, Olof

    2002-02-01

    The wall perturbation correction factor pwall in 60Co for Wellhfer Roos-type plane-parallel ionization chambers is determined experimentally and compared with the results of a previous study using PTW-Roos chambers (Palm et al 2000 Phys. Med. Biol. 45 971-81). Five ionization chambers of the type Wellhfer PPC-35 (or its equivalent PPC-40) are used for the analysis. Wall perturbation correction factors are obtained by assuming ND,air chamber factors determined by cross-calibration in a high-energy electron and in a 60Co ?-ray beam to be equal, and by assigning any differences to the wall perturbation factor. The procedure yields a pwall value of 1.018 (uc = 0.010), which is slightly higher than the value 1.014 (uc = 0.010) formerly obtained for the PTW-Roos chambers using the ND,air method. The chamber-to-chamber variation in pwall for the Wellhfer-Roos chambers is found to be very small, with a maximum difference of 0.3%. The effect of using new pcav values for graphite-walled Farmer-type chambers used in water in electron beams is to decrease pwall by approximately 0.5%. The long- and short-term stability of the Roos-type chambers manufactured by Wellhfer is investigated by measurements at the IAEA Dosimetry Laboratory in Vienna, Austria, and at the Sahlgrenska University Hospital in Gteborg, Sweden. Calibrations made at the IAEA over several months show variations in the ND,w calibration factors larger than expected, based on previous experiences with PTW-Roos chambers. Measurements of the short-term stability of the Wellhfer-Roos chambers show a marked increase in chamber response for the time the chambers are immersed in water, pointing to a possible problem in the chamber design. As a consequence of these findings, Wellhfer is currently working on a re-design of the chamber to solve the stability problem.

  17. Long-term monitoring of hydrogeological activation behaviour of an active landslide system using time-lapse temperature-corrected electrical resistance geophysical measurements

    NASA Astrophysics Data System (ADS)

    Merritt, Andrew; Murphy, William; Chambers, Jonathan; Wilkinson, Paul; West, Jared; Uhlemann, Sebastian

    2015-04-01

    If the effects of landslides are to be mitigated and avoided then the causes of landslide activations - and re-activations - must be better understood. The most common subsurface property change in the lead up to rainfall-triggered landslide activation is the moisture content of slope material and associated pore water pressure rises and/or consistency changes. If these characteristic subsurface physical properties can be observed in advance of activation then early warning of imminent slope activation may be possible. Recent advances in geoelectrical monitoring techniques reveal that time-lapse electrical resistivity tomography (ERT) is a useful tool, capable of observing hillslope hydrogeological processes. However, most previous studies lasted a short time-frame and compared few tomograms. Therefore, a geophysical imaging system through which the progressive wetting of the ground in response to rainfall leading to saturation and then sliding can be observed would seem to be a sensible approach to explore the forecasting of imminent landslide movement. Presented here is the analysis and interpretation of the results of a four and a half year, long-term and high temporal resolution monitoring campaign of a periodically active inland landslide, located in the UK, by a geoelectrical monitoring system called Automated time-Lapse Electrical Resistivity Tomography (ALERT). Time-lapse temperature-corrected transfer resistances reveal that the system responds very well to rises and falls in piezometric level and seasonal trends of soil desiccation during warmer, drier months and crack annealing and soil moisture accumulation in response to wetter periods. The existence of threshold slope moisture contents, and hence electrical resistances, above which the slope activates are not observed in resistance/resistivity results most probably due to the complex nature of the landslide system, the monitoring system resolution and a number of physical slope processes taking place. An exciting development is our improved understanding of shallow earthflow pre-activation hydrogeological behaviour. When interpreted alongside piezometry, an apparent increase in resistance in the months preceding earthflow activation reveals subtle geomechanical processes occurring, including slip surface drainage, due to soil dilation, as strain develops. Correlation between piezometric level fall and associated temperature-corrected resistance rise highlight the sensitivity of the geophysical monitoring system to landslide hydrogeological processes.

  18. Extremely high Q-factor mechanical modes in quartz bulk acoustic wave resonators at millikelvin temperature

    SciTech Connect

    Goryachev, M.; Creedon, D. L.; Ivanov, E. N.; Tobar, M. E.; Galliou, S.; Bourquin, R.

    2014-12-04

    We demonstrate that Bulk Acoustic Wave (BAW) quartz resonator cooled down to millikelvin temperatures are excellent building blocks for hybrid quantum systems with extremely long coherence times. Two overtones of the longitudinal mode at frequencies of 15.6 and 65.4 MHz demonstrate a maximum f.Q product of 7.810{sup 16} Hz. With this result, the Q-factor in such devices near the quantum ground state can be four orders of magnitude better than previously attained in other mechanical systems. Tested quartz resonators possess the ultra low acoustic losses crucial for electromagnetic cooling to the phonon ground state.

  19. Characterization of radiation beams used to determinate the correction factor for a CyberKnife unit reference field using ionization chambers

    NASA Astrophysics Data System (ADS)

    Aragn-Martnez, Nestor; Gmez-Muoz, Arnulfo; Massillon-JL, Guerda

    2014-11-01

    This paper aimed to characterize a 6 MV x-ray beam from a Varian iX linear accelerator in order to obtain the correction factors needed by the IAEA/AAPM new formalism1. The experiments were performed in a liquid water phantom under different irradiation conditions: a) Calibration of the reference field of 10 cm 10 cm at 90 cm SSD and 10 cm depth was carried out according to the TRS-398 protocol using three ionization chambers (IC) calibrated in different reference laboratory and b) Measurement of the absorbed dose rate at 70 cm SSD and 10 cm depth in a 10 cm 10 cm and 5.4 cm 5.4 cm fields was obtained in order to simulate the CyberKnife conditions where maximum distance between the source and the detector is equal to 80 cm and the maximum field size is 6 cm diameter. Depending where the IC was calibrated, differences between 0.16% and 2.24% in the absorbed dose rate measured in the 10 cm 10 cm field at 90 cm SSD were observed, while for the measurements at 70 cm SSD, differences between 1.27% and 3.88% were obtained. For the 5.4 cm 5.4 cm field, the absorbed dose measured with the three ICs varies between 1.37% and 3.52%. The increase in the difference on the absorbed dose when decreasing the SSD could possibly be associated to scattering radiation generated from the collimators and/or the energy dependence of the ionization chambers to low-energy radiation. The results presented in this work suggest the importance of simulating the CyberKnife conditions using other linear accelerator for obtaining the correction factors as proposed by the IAEA/AAPM new formalism in order to measure the absorbed dose with acceptable accuracy.

  20. Characterization of radiation beams used to determinate the correction factor for a CyberKnife® unit reference field using ionization chambers

    SciTech Connect

    Aragón-Martínez, Nestor Massillon-JL, Guerda; Gómez-Muñoz, Arnulfo

    2014-11-07

    This paper aimed to characterize a 6 MV x-ray beam from a Varian® iX linear accelerator in order to obtain the correction factors needed by the IAEA/AAPM new formalism{sup 1}. The experiments were performed in a liquid water phantom under different irradiation conditions: a) Calibration of the reference field of 10 cm × 10 cm at 90 cm SSD and 10 cm depth was carried out according to the TRS-398 protocol using three ionization chambers (IC) calibrated in different reference laboratory and b) Measurement of the absorbed dose rate at 70 cm SSD and 10 cm depth in a 10 cm × 10 cm and 5.4 cm × 5.4 cm fields was obtained in order to simulate the CyberKnife® conditions where maximum distance between the source and the detector is equal to 80 cm and the maximum field size is 6 cm diameter. Depending where the IC was calibrated, differences between 0.16% and 2.24% in the absorbed dose rate measured in the 10 cm × 10 cm field at 90 cm SSD were observed, while for the measurements at 70 cm SSD, differences between 1.27% and 3.88% were obtained. For the 5.4 cm × 5.4 cm field, the absorbed dose measured with the three ICs varies between 1.37% and 3.52%. The increase in the difference on the absorbed dose when decreasing the SSD could possibly be associated to scattering radiation generated from the collimators and/or the energy dependence of the ionization chambers to low-energy radiation. The results presented in this work suggest the importance of simulating the CyberKnife® conditions using other linear accelerator for obtaining the correction factors as proposed by the IAEA/AAPM new formalism in order to measure the absorbed dose with acceptable accuracy.

  1. Monte Carlo computed machine-specific correction factors for reference dosimetry of TomoTherapy static beam for several ion chambers

    SciTech Connect

    Sterpin, E.; Mackie, T. R.; Vynckier, S.

    2012-07-15

    Purpose: To determine k{sub Q{sub m{sub s{sub r,Q{sub o}{sup f{sub m}{sub s}{sub r},f{sub o}}}}}} correction factors for machine-specific reference (msr) conditions by Monte Carlo (MC) simulations for reference dosimetry of TomoTherapy static beams for ion chambers Exradin A1SL, A12; PTW 30006, 31010 Semiflex, 31014 PinPoint, 31018 microLion; NE 2571. Methods: For the calibration of TomoTherapy units, reference conditions specified in current codes of practice like IAEA/TRS-398 and AAPM/TG-51 cannot be realized. To cope with this issue, Alfonso et al. [Med. Phys. 35, 5179-5186 (2008)] described a new formalism introducing msr factors k{sub Q{sub m{sub s{sub r,Q{sub o}{sup f{sub m}{sub s}{sub r},f{sub o}}}}}} for reference dosimetry, applicable to static TomoTherapy beams. In this study, those factors were computed directly using MC simulations for Q{sub 0} corresponding to a simplified {sup 60}Co beam in TRS-398 reference conditions (at 10 cm depth). The msr conditions were a 10 Multiplication-Sign 5 cm{sup 2} TomoTherapy beam, source-surface distance of 85 cm and 10 cm depth. The chambers were modeled according to technical drawings using the egs++ package and the MC simulations were run with the egs{sub c}hamber user code. Phase-space files used as the source input were produced using PENELOPE after simulation of a simplified {sup 60}Co beam and the TomoTherapy treatment head modeled according to technical drawings. Correlated sampling, intermediate phase-space storage, and photon cross-section enhancement variance reduction techniques were used. The simulations were stopped when the combined standard uncertainty was below 0.2%. Results: Computed k{sub Q{sub m{sub s{sub r,Q{sub o}{sup f{sub m}{sub s}{sub r},f{sub o}}}}}} values were all close to one, in a range from 0.991 for the PinPoint chamber to 1.000 for the Exradin A12 with a statistical uncertainty below 0.2%. Considering a beam quality Q defined as the TPR{sub 20,10} for a 6 MV Elekta photon beam (0.661), the additional correction k{sub Q{sub m{sub s{sub r{sub ,Q}{sup f{sub m}{sub s}{sub r}{sub ,}f{sub r}{sub e}{sub f}}}}}} to k{sub Q,Q{sub o}} defined in Alfonso et al. [Med. Phys. 35, 5179-5186 (2008)] formalism was in a range from 0.997 to 1.004.Conclusion: The MC computed factors in this study are in agreement with measured factors for chamber types already studied in literature. This work provides msr correction factors for additional chambers used in reference dosimetry. All of them were close to one (within 1%).

  2. Nuclear temperature measurements with helium isotopes

    NASA Astrophysics Data System (ADS)

    Miniball/Multics Collaboration; Xi, H.; Tsang, M. B.; Huang, M. J.; Lynch, W. G.; Dinius, J. D.; Gaff, S. J.; Gelbke, C. K.; Glasmacher, T.; Kunde, G. J.; Martin, L.; Montoya, C. P.; Azzano, M.; Margagliotti, G. V.; Milazzo, P. M.; Rui, R.; Vannini, G.; Celano, L.; Colonna, N.; Tagliente, G.; D'Agostino, M.; Bruno, M.; Fiandri, M. L.; Gramegna, F.; Ferrero, A.; Iori, I.; Moroni, A.; Petruzzelli, F.; Mastinu, P. F.

    1998-07-01

    Temperatures extracted with the family of (3He, 4He) isotope ratio thermometers, THe, have been studied and cross-checked with temperatures, T(4He*) constructed from excited and ground state populations of 4He. Empirical correction factors provide baseline corrections for sequential decay effects for THe<4.5 MeV, independent of projectile, target and incident energies. After corrections for fluctuations due to sequential decay, statistical calculations predict that THe and T(4He*) should agree.

  3. WE-E-18A-05: Bremsstrahlung of Laser-Plasma Interaction at KeV Temperature: Forward Dose and Attenuation Factors

    SciTech Connect

    Saez-Beltran, M; Fernandez Gonzalez, F

    2014-06-15

    Purpose: To obtain an analytical empirical formula for the photon dose source term in forward direction from bremsstrahlung generated from laser-plasma accelerated electron beams in aluminum solid targets, with electron-plasma temperatures in the 10–100 keV energy range, and to calculate transmission factors for iron, aluminum, methacrylate, lead and concrete and air, materials most commonly found in vacuum chamber labs. Methods: Bremsstrahlung fluence is calculated from the convolution of thin-target bremsstrahlung spectrum for monoenergetic electrons and the relativistic Maxwell-Juettner energy distribution for the electron-plasma. Unattenuatted dose in tissue is calculated by integrating the photon spectrum with the mass-energy absorption coefficient. For the attenuated dose, energy dependent absorption coefficient, build-up factors and finite shielding correction factors were also taken into account. For the source term we use a modified formula from Hayashi et al., and we fitted the proportionality constant from experiments with the aid of the previously calculated transmission factors. Results: The forward dose has a quadratic dependence on electron-plasma temperature: 1 joule of effective laser energy transferred to the electrons at 1 m in vacuum yields 0,72 Sv per MeV squared of electron-plasma temperature. Air strongly filters the softer part of the photon spectrum and reduce the dose to one tenth in the first centimeter. Exponential higher energy tail of maxwellian spectrum contributes mainly to the transmitted dose. Conclusion: A simple formula for forward photon dose from keV range temperature plasma is obtained, similar to those found in kilovoltage x-rays but with higher dose per dissipated electron energy, due to thin target and absence of filtration.

  4. Two-Dimensional Thermal Boundary Layer Corrections for Convective Heat Flux Gauges

    NASA Technical Reports Server (NTRS)

    Kandula, Max; Haddad, George

    2007-01-01

    This work presents a CFD (Computational Fluid Dynamics) study of two-dimensional thermal boundary layer correction factors for convective heat flux gauges mounted in flat plate subjected to a surface temperature discontinuity with variable properties taken into account. A two-equation k - omega turbulence model is considered. Results are obtained for a wide range of Mach numbers (1 to 5), gauge radius ratio, and wall temperature discontinuity. Comparisons are made for correction factors with constant properties and variable properties. It is shown that the variable-property effects on the heat flux correction factors become significant

  5. Surface air temperature changes from 1909 to 2008 in Southeast Asia assessed by factor analysis

    NASA Astrophysics Data System (ADS)

    Chooprateep, Suree; McNeil, Nittaya

    2016-01-01

    Monthly seasonally adjusted surface temperature patterns in Southeast Asia from 1909 to 2008 were studied. The area comprised 40 regions of 10° × 10° grid boxes in latitudes 25°S to 25°N and longitudes 75°E to 160°E. Temperatures were studied for three overlapping 36-year periods, the first period 1909-1944, the second period 1941-1976 and the third period 1973-2008. The data of each 36-year period were fitted to reduce autocorrelations at lags 1 and 2 months. Factor analysis was used to account for spatial correlation between grid boxes giving six contiguous layer regions. Simple linear regression models were fitted to data within these larger regions. Temperatures were found to have increased in five from six regions over the first period with the increases ranging from 0.005 to 0.148 °C per decade, in only three regions over the second period with the increases ranging from 0.008 to 0.150 °C per decade and in six regions over the third period with the increases ranging from 0.082 to 0.222 °C per decade.

  6. Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam

    PubMed Central

    Pham, C. H.; Vu, C. C.; Sommer, S. G.; Bruun, S.

    2014-01-01

    This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank. PMID:25050049

  7. A Practical Methodology to Measure Unbiased Gas Chromatographic Retention Factor vs. Temperature Relationships

    PubMed Central

    Peng, Baijie; Kuo, Mei-Yi; Yang, Panhia; Hewitt, Joshua T.; Boswell, Paul G.

    2014-01-01

    Compound identification continues to be a major challenge. Gas chromatography-mass spectrometry (GC-MS) is a primary tool used for this purpose, but the GC retention information it provides is underutilized because existing retention databases are experimentally restrictive and unreliable. A methodology called retention projection has the potential to overcome these limitations, but it requires the retention factor (k) vs. T relationship of a compound to calculate its retention time. Direct methods of measuring k vs. T relationships from a series of isothermal runs are tedious and time-consuming. Instead, a series of temperature programs can be used to quickly measure the k vs. T relationships, but they are generally not as accurate when measured this way because they are strongly biased by non-ideal behavior of the GC system in each of the runs. In this work, we overcome that problem by using the retention times of 25 n-alkanes to back-calculate the effective temperature profile and hold-up time vs. T profiles produced in each of six temperature programs. When the profiles were measured this way and taken into account, the k vs. T relationships measured from each of two different GC-MS instruments were nearly as accurate as the ones measured isothermally, showing less than 2-fold more error. Furthermore, temperature-programmed retention times calculated in five other labs from the new k vs. T relationships had the same distribution of error as when they were calculated from k vs. T relationships measured isothermally. Free software was developed to make the methodology easy to use. The new methodology potentially provides a relatively fast and easy way to measure unbiased k vs. T relationships. PMID:25496658

  8. A practical methodology to measure unbiased gas chromatographic retention factor vs. temperature relationships.

    PubMed

    Peng, Baijie; Kuo, Mei-Yi; Yang, Panhia; Hewitt, Joshua T; Boswell, Paul G

    2014-12-29

    Compound identification continues to be a major challenge. Gas chromatography-mass spectrometry (GC-MS) is a primary tool used for this purpose, but the GC retention information it provides is underutilized because existing retention databases are experimentally restrictive and unreliable. A methodology called "retention projection" has the potential to overcome these limitations, but it requires the retention factor (k) vs. T relationship of a compound to calculate its retention time. Direct methods of measuring k vs. T relationships from a series of isothermal runs are tedious and time-consuming. Instead, a series of temperature programs can be used to quickly measure the k vs. T relationships, but they are generally not as accurate when measured this way because they are strongly biased by non-ideal behavior of the GC system in each of the runs. In this work, we overcome that problem by using the retention times of 25 n-alkanes to back-calculate the effective temperature profile and hold-up time vs. T profiles produced in each of the six temperature programs. When the profiles were measured this way and taken into account, the k vs. T relationships measured from each of two different GC-MS instruments were nearly as accurate as the ones measured isothermally, showing less than two-fold more error. Furthermore, temperature-programmed retention times calculated in five other laboratories from the new k vs. T relationships had the same distribution of error as when they were calculated from k vs. T relationships measured isothermally. Free software was developed to make the methodology easy to use. The new methodology potentially provides a relatively fast and easy way to measure unbiased k vs. T relationships. PMID:25496658

  9. Mechanism and Influencing Factors of Iron Nuggets Forming in Rotary Hearth Furnace Process at Lower Temperature

    NASA Astrophysics Data System (ADS)

    Han, Hongliang; Duan, Dongping; Chen, Siming; Yuan, Peng

    2015-10-01

    In order to improve the efficiency of slag and iron separation, a new idea of "the separation of slag (solid state) and iron (molten state) in rotary hearth furnace process at lower temperature" is put forward. In this paper, the forming process of iron nuggets has been investigated. Based on those results, the forming mechanisms and influencing factors of iron nugget at low temperature are discussed experimentally using an electric resistance furnace simulating a rotary hearth furnace process. Results show that the reduction of iron ore, carburization of reduced iron, and the composition and quantity of slag are very important for producing iron nuggets at lower temperature. Reduction reaction of carbon-containing pellets is mainly at 1273 K and 1473 K (1000 °C and 1200 °C). When the temperature is above 1473 K (1200 °C), the metallization rate of carbon-containing pellets exceeds 93 pct, and the reduction reaction is substantially complete. Direct carburization is the main method for carburization of reduced iron. This reaction occurs above 1273 K (1000 °C), with carburization degree increasing greatly at 1473 K and 1573 K (1200 °C and 1300 °C) after particular holding times. Besides, to achieve the "slag (solid state) and iron (molten state) separation," the melting point of the slag phase should be increased. Slag (solid state) and iron (molten state) separation can be achieved below 1573 K (1300 °C), and when the holding time is 20 minutes, C/O is 0.7, basicity is less than 0.5 and a Na2CO3 level of 3 pct, the recovery rate of iron can reach 90 pct, with a proportion of iron nuggets more than 3.15 mm of nearly 90 pct. This study can provide theoretical and technical basis for iron nugget production.

  10. Molecular Factors and Biochemical Pathways Induced by Febrile Temperature in Intraerythrocytic Plasmodium falciparum Parasites▿ †

    PubMed Central

    Oakley, Miranda S. M.; Kumar, Sanjai; Anantharaman, Vivek; Zheng, Hong; Mahajan, Babita; Haynes, J. David; Moch, J. Kathleen; Fairhurst, Rick; McCutchan, Thomas F.; Aravind, L.

    2007-01-01

    Intermittent episodes of febrile illness are the most benign and recognized symptom of infection with malaria parasites, although the effects on parasite survival and virulence remain unclear. In this study, we identified the molecular factors altered in response to febrile temperature by measuring differential expression levels of individual genes using high-density oligonucleotide microarray technology and by performing biological assays in asexual-stage Plasmodium falciparum parasite cultures incubated at 37°C and 41°C (an elevated temperature that is equivalent to malaria-induced febrile illness in the host). Elevated temperature had a profound influence on expression of individual genes; 336 of approximately 5,300 genes (6.3% of the genome) had altered expression profiles. Of these, 163 genes (49%) were upregulated by twofold or greater, and 173 genes (51%) were downregulated by twofold or greater. In-depth sensitive sequence profile analysis revealed that febrile temperature-induced responses caused significant alterations in the major parasite biologic networks and pathways and that these changes are well coordinated and intricately linked. One of the most notable transcriptional changes occurs in genes encoding proteins containing the predicted Pexel motifs that are exported into the host cytoplasm or inserted into the host cell membrane and are likely to be associated with erythrocyte remodeling and parasite sequestration functions. Using our sensitive computational analysis, we were also able to assign biochemical or biologic functional predictions for at least 100 distinct genes previously annotated as “hypothetical.” We find that cultivation of P. falciparum parasites at 41°C leads to parasite death in a time-dependent manner. The presence of the “crisis forms” and the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling-positive parasites following heat treatment strongly support the notion that an apoptosis-like cell death mechanism might be induced in response to febrile temperatures. These studies enhance the possibility of designing vaccines and drugs on the basis of disruption in molecules and pathways of parasite survival and virulence activated in response to febrile temperatures. PMID:17283083

  11. Environmental factors affecting the low temperature isomerization of homohopanes in acidic peat deposits, central China

    NASA Astrophysics Data System (ADS)

    Huang, Xianyu; Meyers, Philip A.; Xue, Jiantao; Gong, Linfeng; Wang, Xinxin; Xie, Shucheng

    2015-04-01

    Progressively more evidence reveals the abundant occurrence of the C31 homohopane with a 17?, 21?-configuration (C31 ??) in immature peats. This compound is commonly considered to be an indicator of thermal maturity in petroleum source rocks, but in peats it has also been interpreted to reflect the oxidation and subsequent decarboxylation reactions of bacteriohopanepolyols with microbially mediated epimerization at C-17 that is catalyzed by the acidic peat conditions. To learn more about the environmental factors that affect the low-temperature isomerization of homohopanes, we investigated the distribution patterns of homohopanes in a well-studied peat core from the Dajiuhu peatland, central China, together with data from modern surface peat samples from Dajiuhu and three other locations. From comparison with paleotemperature and paleohydrologic records in the peat core, we hypothesize that the ratio of C31 ?? hopane relative to the ?? isomer (C31 ??/??) is mainly influenced on a centennial to millennial timescale by ambient temperature with a secondary effect from redox conditions that are defined by peatland water levels. The surface peat samples revealed that relatively high C31 ??/?? values occurred under pH < 6. These results suggest that pH is indeed an important factor in the low-temperature isomerization of C31 homohopanes, although the magnitude of the pH effect may be less than those of ambient temperature and redox conditions. In both surface peat and peat horizons from the Dajiuhu peatland, the amount of the C31 ?? compound with R configuration relative to that with S configuration (C31 R/S) varied closely with C31 ??/??, suggesting that the epimerization at both C-17 and C-22 may happen synchronously and at similar rates. This study reveals that the isomerization of homohopanes has the potential to reflect paleoenvironmental changes in acidic peat deposits. In addition, acidic peat samples investigated in this and previous studies commonly have relatively high values of C31 ??/?? and C31 R/S, highlighting the potential of homohopane isomers to be tracers of the delivery and deposition of organic matter from acidic settings.

  12. Activity-based anorexia: ambient temperature has been a neglected factor.

    PubMed

    Gutirrez, Emilio; Vzquez, Reyes; Boakes, R A

    2002-06-01

    Activity-based anorexia refers to the self-starvation of rats exposed to experimental conditions that combine restricted access to food with access to an activity wheel. This paper compares previous studies of this phenomenon in relation to the ambient temperatures (AT) that were employed. On this basis, and from some more direct evidence, we argue that AT is an important, but neglected, factor in activity-based anorexia research. More attention to AT is needed in future research, since its neglect threatens the validity of conclusions drawn from those studies. Furthermore, direct examination of the effect of AT on activity-based anorexia will allow a better understanding of the mechanisms underlying this phenomenon and the possible clinical implications for the treatment of human anorexia nervosa. PMID:12120785

  13. Low temperature resistivity, thermoelectricity, and power factor of Nb doped anatase TiO2

    NASA Astrophysics Data System (ADS)

    Ja?imovi?, J.; Gal, R.; Magrez, A.; Piatek, J.; Forr, L.; Nakao, S.; Hirose, Y.; Hasegawa, T.

    2013-01-01

    The resistivity of a very high quality anatase TiO2 doped with 6% of Nb was measured from 300 K down to 40 mK. No sign of superconductivity was detected. Instead, a minute quantity of cation vacancies resulted in a Kondo scattering. Measurements of thermo-electric power and resistivity were extended up to 600 K. The calculated power factor has a peak value of 14 ?W/(K2cm) at 350 K, which is comparable to that of Bi2Te3 [Venkatasubramanian et al., Nature 413, 597 (2001)], the archetype thermolectrics. Taking the literature value for the thermal conductivity of Nb doped TiO2 thin films, the calculated figure of merit (ZT) is in the range of 0.1 above 300 K. This value is encouraging for further engineering of the material in order to reach ZT of 1 suitable for high temperature thermoelectrics.

  14. Study of effective carrier lifetime and ideality factor of BPW 21 and BPW 34B photodiodes from above room temperature to liquid nitrogen temperature

    NASA Astrophysics Data System (ADS)

    Dalapati, P.; Manik, N. B.; Basu, A. N.

    2015-01-01

    In the present work we have studied the temperature dependence of two most important characteristics of the photodiodes (BPW 21and BPW 34B), namely, the ideality factor and the carrier lifetime; both of which are found to change significantly at low temperature. The effective carrier lifetime measured by the Open Circuit Voltage Decay method (OCVD) shows a gradual increase in value from 350 K to about 250 K then sharply decreases by about thirty percent of its highest value at liquid nitrogen temperature, the trend being similar for both the devices. The dark forward current-voltage characteristics over the same temperature range yield the value of ideality factor which increases nearly by a factor of three for both the photodiodes at the liquid nitrogen temperature. The nature of variation of both the parameters has been qualitatively accounted for in terms of the recent tunneling models. The data generated for the first time for the devices and their broad theoretical understanding will help to improve design and application of the photodiodes, particularly at low temperature.

  15. Adaptation of Extremophilic Proteins with Temperature and Pressure: Evidence from Initiation Factor 6.

    PubMed

    Calligari, Paolo A; Calandrini, Vania; Ollivier, Jacques; Artero, Jean-Baptiste; Hrtlein, Michael; Johnson, Mark; Kneller, Gerald R

    2015-06-25

    In this work, we study dynamical properties of an extremophilic protein, Initiation Factor 6 (IF6), produced by the archeabacterium Methanocaldococcus jannascii, which thrives close to deep-sea hydrothermal vents where temperatures reach 80 C and the pressure is up to 750 bar. Molecular dynamics simulations (MD) and quasi-elastic neutron scattering (QENS) measurements give new insights into the dynamical properties of this protein with respect to its eukaryotic and mesophilic homologue. Results obtained by MD are supported by QENS data and are interpreted within the framework of a fractional Brownian dynamics model for the characterization of protein relaxation dynamics. IF6 from M. jannaschii at high temperature and pressure shares similar flexibility with its eukaryotic homologue from S. cerevisieae under ambient conditions. This work shows for the first time, to our knowledge, that the very common pattern of corresponding states for thermophilic protein adaptation can be extended to thermo-barophilic proteins. A detailed analysis of dynamic properties and of local structural fluctuations reveals a complex pattern for "corresponding" structural flexibilities. In particular, in the case of IF6, the latter seems to be strongly related to the entropic contribution given by an additional, C-terminal, 20 amino-acid tail which is evolutionary conserved in all mesophilic IF6s. PMID:25996652

  16. Daily and Interannual Variability of Air Temperature and Precipitation As Agricultural Factor

    NASA Astrophysics Data System (ADS)

    Sourkova, G.; Pona, C.

    The problem investigated concerns wheat growing process sensitivity to the changes in climate variability. For the sensitivity analysis five CERES-model runs are held for three stations in Italy: Decimomannu (Sardinia), Brindisi (Apulia) and Ghedi (Padana valley, Veneto). The only difference between these five experiments for each station is a weather input. All five weather inputs for each location are simulated by weather generator WXGEN. First run ("base") is forced by weather input having tempera- ture and precipitation variance equal to the present-day values (1960-1990). Then two crop simulations are made with changed "base" interannual variance of monthly to- tal precipitation by multiplicative factors 0.5 and 2. Temperature variability remains unchanged. Last two model runs are carried out with daily halved and doubled temper- ature variance, precipitation variability is the same as in "base" simulation. Investiga- tion showed that doubled precipitation variability is accompanied at all three locations by the largest amounts of yield variability for all five scenarios. Decreased precipi- tation variability is followed by yield decline and, at the same time the amplitude of yield change is the least compared with other forcings. Decreasing of precipitation variability results in noticeably raised harvest index for the years of minimum yield. For Decimomannu and Brindisi it is almost equal to that of the maximum yield years. In general, more significantly expressed response of the yield amounts occurs for pre- cipitation variability forcings. The influence of temperature variability changes seems to be less for all three locations.

  17. Stress corrosion cracking of alloy 600 in high temperature aqueous solutions: Influencing factors, mechanisms and models

    SciTech Connect

    Szklarska-Smialowska, Z.; Rebak, R.B.

    1996-12-31

    A detailed critical review of the multiple variables affecting stress corrosion cracking (SCC) of in high temperature (deaerated) aqueous solutions is given. Most of the data in the literature deals with the cracking susceptibility in the primary side; however, it is clear that similar factors and to a similar extent influence the SCC susceptibility in both primary and secondary sides. Some factors such as alkalinity of the solution or presence of lead (Pb) may be more in the secondary side and others such as partial pressure of hydrogen (H{sub 2}) in the primary side. Even though the effect of the variables on SCC susceptibility is more or less established, in models, in most of the cases there is a lack of fundamental understanding of the mechanisms involved. The different mechanisms and models proposed to explain the SCC of alloy 600 are briefly reviewed and their validity to explain the influence of the variables and to predict the crack growth rate (CGR), is assessed. It is concluded that several of the proposed models seem to give a fair estimate of the CGR values under certain conditions; however, it appears that a single mechanism cannot explain in detail the complex case of alloy 600 SCC. 113 refs., 11 figs., 3 tabs.

  18. A regional extreme low temperature event and its main atmospheric contributing factors

    NASA Astrophysics Data System (ADS)

    Gong, Zhiqiang; Feng, Guolin; Ren, Fumin; Li, Jianping

    2014-07-01

    The regional extreme low temperature event from December 30, 2010 to February 2, 2011 was a very rare and protracted cold event with the largest integrated index ( Z) since 1979. Two meteorological factors could be responsible for this extreme winter event. First, a persistent blocking pattern existed in the mid-latitudes. This not only allowed cold air to persist in southern China but also enabled each perturbation from the west propagating around the blocking high to trigger downstream cold air intrusions from the north. Second, the consistently downward negative Arctic Oscillation (AO) was favorable for the eastward moving of Rossby waves in middle latitudes, which made the upper reaches positive center in SLP and negative center in Z500 move to East Asia. This stable and consistent situation favored the polar area cold air invasion to the mid-latitude region. Of these two factors, the blocking pattern was likely to be the direct cause, the co-effects of consistently strong downward negative AO from the stratosphere, and the corresponding eastward moving wave train in Z500 and SLP might be the prophase teleconnection culprit.

  19. JAIBA, a class-II HD-ZIP transcription factor involved in the regulation of meristematic activity, and important for correct gynoecium and fruit development in Arabidopsis.

    PubMed

    Ziga-Mayo, Victor M; Marsch-Martnez, Nayelli; de Folter, Stefan

    2012-07-01

    The gynoecium is one of the most complex organs of a plant. After fertilization, it becomes a fruit, which has two important functions: to protect the seeds while they develop and to disperse them at maturity. The development and patterning of the gynoecium and later fruit must be finely regulated to ensure the survival of the species that produces them. The process that leads to successful fruit formation starts at early stages of floral meristem development and follows a series of chronologically successive events. In this work we report the functional characterization of the class-II homeodomain leucine zipper (HD-ZIP) JAIBA (JAB) gene. Mutant jab plants show sporophytic defects in male and female reproductive development, and combined with crabs claw cause defects in the floral meristem (FM) determination process and gynoecium medial tissue development. This suggests that proper FM determination is required for gynoecium medial tissue development, and indicates that JAB and CRC are necessary for both processes. Furthermore, the JAB protein interacts with transcription factors known to regulate meristematic activity, fruit development, and floral meristem determinacy. The sporophytic effect on pollen and embryo sac development might be an independent and later function of JAB. In summary, we present data that indicates that the JAB gene regulates meristematic activity in different tissues, and that it is necessary for the correct formation of the gynoecium at different stages, contributing to a crucial process in plant life: proper fruit development. PMID:22409594

  20. Long-term correction of inhibitor-prone hemophilia B dogs treated with liver-directed AAV2-mediated factor IX gene therapy.

    PubMed

    Niemeyer, Glenn P; Herzog, Roland W; Mount, Jane; Arruda, Valder R; Tillson, D Michael; Hathcock, John; van Ginkel, Frederik W; High, Katherine A; Lothrop, Clinton D

    2009-01-22

    Preclinical studies and initial clinical trials have documented the feasibility of adenoassociated virus (AAV)-mediated gene therapy for hemophilia B. In an 8-year study, inhibitor-prone hemophilia B dogs (n = 2) treated with liver-directed AAV2 factor IX (FIX) gene therapy did not have a single bleed requiring FIX replacement, whereas dogs undergoing muscle-directed gene therapy (n = 3) had a bleed frequency similar to untreated FIX-deficient dogs. Coagulation tests (whole blood clotting time [WBCT], activated clotting time [ACT], and activated partial thromboplastin time [aPTT]) have remained at the upper limits of the normal ranges in the 2 dogs that received liver-directed gene therapy. The FIX activity has remained stable between 4% and 10% in both liver-treated dogs, but is undetectable in the dogs undergoing muscle-directed gene transfer. Integration site analysis by linear amplification-mediated polymerase chain reaction (LAM-PCR) suggested the vector sequences have persisted predominantly in extrachromosomal form. Complete blood count (CBC), serum chemistries, bile acid profile, hepatic magnetic resonance imaging (MRI) and computed tomography (CT) scans, and liver biopsy were normal with no evidence for tumor formation. AAV-mediated liver-directed gene therapy corrected the hemophilia phenotype without toxicity or inhibitor development in the inhibitor-prone null mutation dogs for more than 8 years. PMID:18957684

  1. Bioengineered coagulation factor VIII enables long-term correction of murine hemophilia A following liver-directed adeno-associated viral vector delivery.

    PubMed

    Brown, Harrison C; Wright, J Fraser; Zhou, Shangzhen; Lytle, Allison M; Shields, Jordan E; Spencer, H Trent; Doering, Christopher B

    2014-01-01

    Clinical data support the feasibility and safety of adeno-associated viral (AAV) vectors in gene therapy applications. Despite several clinical trials of AAV-based gene transfer for hemophilia B, a unique set of obstacles impede the development of a similar approach for hemophilia A. These include (i) the size of the factor VIII (fVIII) transgene, (ii) humoral immune responses to fVIII, (iii) inefficient biosynthesis of human fVIII, and (iv) AAV vector immunity. Through bioengineering approaches, a novel fVIII molecule, designated ET3, was developed and shown to improve biosynthetic efficiency 10- to 100-fold. In this study, the utility of ET3 was assessed in the context of liver-directed, AAV-mediated gene transfer into hemophilia A mice. Due to the large size of the expression cassette, AAV-ET3 genomes packaged into viral particles as partial genome fragments. Despite this potential limitation, a single peripheral vein administration of AAV-ET3 into immune-competent hemophilia A mice resulted in correction of the fVIII deficiency at lower vector doses than previously reported for similarly oversized AAV-fVIII vectors. Therefore, ET3 appears to improve vector potency and mitigate at least one of the critical barriers to AAV-based clinical gene therapy for hemophilia A. PMID:26015976

  2. Bioengineered coagulation factor VIII enables long-term correction of murine hemophilia A following liver-directed adeno-associated viral vector delivery

    PubMed Central

    Brown, Harrison C; Wright, J Fraser; Zhou, Shangzhen; Lytle, Allison M; Shields, Jordan E; Spencer, H Trent; Doering, Christopher B

    2014-01-01

    Clinical data support the feasibility and safety of adeno-associated viral (AAV) vectors in gene therapy applications. Despite several clinical trials of AAV-based gene transfer for hemophilia B, a unique set of obstacles impede the development of a similar approach for hemophilia A. These include (i) the size of the factor VIII (fVIII) transgene, (ii) humoral immune responses to fVIII, (iii) inefficient biosynthesis of human fVIII, and (iv) AAV vector immunity. Through bioengineering approaches, a novel fVIII molecule, designated ET3, was developed and shown to improve biosynthetic efficiency 10- to 100-fold. In this study, the utility of ET3 was assessed in the context of liver-directed, AAV-mediated gene transfer into hemophilia A mice. Due to the large size of the expression cassette, AAV-ET3 genomes packaged into viral particles as partial genome fragments. Despite this potential limitation, a single peripheral vein administration of AAV-ET3 into immune-competent hemophilia A mice resulted in correction of the fVIII deficiency at lower vector doses than previously reported for similarly oversized AAV-fVIII vectors. Therefore, ET3 appears to improve vector potency and mitigate at least one of the critical barriers to AAV-based clinical gene therapy for hemophilia A. PMID:26015976

  3. EFFECT OF ENVIRONMENTAL FACTORS ON PHYTOPLANKTON GROWTH: TEMPERATURE AND THE INTERACTIONS OF TEMPERATURE WITH NUTRIENT LIMITATION (JOURNAL VERSION)

    EPA Science Inventory

    The combined stress of nutrient limitation and suboptimal temperature on growth was studied with turbidostat and chemostat cultures of Scenedesmus sp. and Asterionella formosa. The combined effects were greater than the sum of individual effects and were not multiplicative. In N-...

  4. Calculation of calibration figures and the volume correction factors for 90Y, 125I, 131I and 177Lu radionuclides based on Monte-Carlo ionization chamber simulation method

    NASA Astrophysics Data System (ADS)

    Kryeziu, D.; Tschurlovits, M.; Kreuziger, M.; Maringer, F.-J.

    2007-09-01

    Many metrology laboratories are dealing with activity measurements of different radionuclides with special interest in nuclear medicine as well as in radiopharmaceutical industry. In improving the accuracy of radionuclide activity measurements, a key role plays the calculation of calibration figures and the volume correction factors for the radionuclide under study. It is well known that the chamber calibration factors depend on the measurement geometry including the volume of the source and the type of the measurement vessel. In this work, the activity standards in the form of radioactive solutions are delivered in sealed Jena glass 5 ml FIOLAX ®-klar ampoule. Calculation of the calibration figures (or efficiencies) for 90Y, 125I, 131I and 177Lu radionuclides on 5 ml ampoule are presented in this paper. Additionally, their appropriate volume correction factors are determined. These calibration figures for the ISOCAL IV pressurized well re-entrant ionization chamber (IC) are pointed out based on the Monte-Carlo (MC) simulation method of such chamber using the PENELOPE-2005 MC computer simulation code. The chamber is filled with nitrogen gas pressurized to approximately 1 MPa. In determining the volume correction factors, the variation of calibration factors versus the mass of radioactive solution filling the 5 ml ampoule glass is investigated. From the point of view that impurity of 177 mLu isomer is always accompanying the 177Lu radionuclide, for making possible the correction due to presence of this impurity, the calibration factor and the volume correction factors for 177 mLu are reported as well.

  5. Energy correction factors of LiF powder TLDs irradiated in high-energy electron beams and applied to mailed dosimetry for quality assurance networks.

    PubMed

    Marre, D; Ferreira, I H; Bridier, A; Bjreland, A; Svensson, H; Dutreix, A; Chavaudra, J

    2000-12-01

    Absorbed dose determination with thermoluminescent dosimeters (TLDs) generally relies on calibration in 60Co gamma-ray reference beams. The energy correction factor fCo(E) for electron beams takes into account the difference between the response of the TLD in the beam of energy E and in the 60Co gamma-ray beam. In this work, fCo(E) was evaluated for an LiF powder irradiated in electron beams of 6 to 20 MeV (Varian 2300C/D) and 10 to 50 MeV (Racetrack MM50), and its variation with electron energy, TLD size and nature of the surrounding medium was also studied for LiF powder. The results have been applied to the ESTRO-EQUAL mailed dosimetry quality assurance network. Monte Carlo calculations (EGS4, PENELOPE) and experiments have been performed for the LiF powder (rho = 1.4 g cm3) (DTL937, Philitech, France), read on a home made reader and a PCL3 automatic reader (Fimel, France). The TLDs were calibrated using Fricke dosimetry and compared with three ionization chambers (NE2571, NACP02, ROOS). The combined uncertainties in the experimental fCo(E) factors determined in this work are less than about 0.4% (1 SD), which is appreciably smaller than the uncertainties up to 1.4% (1 SD) reported for other calculated values in the literature. Concerning the Varian 2300C/D beams, the measured fCo(E) values decrease from 1.065 to 1.049 +/- 0.004 (1 SD) when the energy at depth in water increases from 2.6 to 14.1 MeV; the agreement with Monte Carlo calculations is better than 0.5%. For the Racetrack MM50 pulsed-scanned beams, the average experimental value of fCo(E) is 1.071 +/- 0.005 (1 SD) for a mean electron energy at depth Ez ranging from 4.3 to 36.3 MeV: fCo(E) is up to 2% higher for the MM50 beams than for the 2300C/D beams in the range of the tested energies. The energy correction factor for LiF powder (3 mm diameter and 15 mm length) varies with beam quality and type (pulsed or pulsed-scanning), cavity size and nature of the surrounding medium. The fCo(E) values obtained for the LiF powder (3 mm diameter and 15 mm length) irradiated in water, have been applied to the EQUAL external audit network, leading to a good agreement between stated and measured doses, with a mean value of 1.002 +/- 0.022 (1 SD), for 170 beam outputs checked (36 electron beam energies) in 13 'reference' radiotherapy centres in Europe. Such fCo(E) data improve the accuracy of the absorbed dose TLD determination in electron beams, justifying their use for quality control in radiotherapy. PMID:11131191

  6. Sensitivity of the hydrological cycle to corrections of the sea surface temperature biases over southern Africa in a regional climate model

    NASA Astrophysics Data System (ADS)

    Weber, Torsten; Hnsler, Andreas; Jacob, Daniela

    2015-04-01

    High resolution climate change projections of the hydrological cycle are of particular importance for southern Africa since possible changes of the climate will affect the water availability and thus the lives of the people in this region. In order to obtain high resolution climate change information for the future, regional climate models (RCMs) are used to downscale climate change projections generated with general circulation models (GCMs). These GCMs are usually coupled with an ocean model providing ocean parameters such as sea surface temperature (SST) needed by GCMs. The hydrological cycle in southern Africa is strongly affected by the moisture transport from the Atlantic and Indian Ocean and, consequently, from their SSTs. In the Atlantic Ocean, the cold up-welling Benguela current flows up the west coast of southern Africa whereas the Agulhas current flows down the east coast in the Indian Ocean. Deficiencies in the description and representation of such currents in ocean models cause biases in simulated SSTs and affect the moisture uptake of lower air layers. Initially, a historical simulation conducted with the general circulation model ECHAM6 was downscaled with the regional climate model REMO to a spatial resolution of 50 x 50 km for the whole African continent. To analyse the sensitivity of the hydrological cycle to SST corrections, five experiments were carried out with REMO covering five simulation years. The five sensitivity experiments were downscaled with REMO to a spatial resolution of 25 x 25 km for southern Africa using the coarser simulation as input. In the first experiment, the entire SST in the coupled ECHAM6 simulation both of the Atlantic and Indian ocean was replaced by the SST from the ERA-Interim reanalysis data, and in two another ones, only the Atlantic Ocean with the Benguela current and the Indian Ocean including the Agulhas current were replaced by the SST from the ERA-Interim reanalysis data, respectively. Besides a control experiment, in which the SST from the coupled ECHAM6 simulation has been kept unchanged, an experiment with perturbed atmospheric conditions was performed with REMO to assess the internal model variability. The results show a distinct impact of the SST biases on the hydrological cycle in southern Africa. In particular, the contribution of the SST bias of the Atlantic Ocean is stronger, which should be taken into account for climate change projections.

  7. High-Temperature Protein G Is an Essential Virulence Factor of Leptospira interrogans

    PubMed Central

    King, Amy M.; Pretre, Gabriela; Bartpho, Thanatchaporn; Sermswan, Rasana W.; Toma, Claudia; Suzuki, Toshihiko; Eshghi, Azad; Picardeau, Mathieu; Murray, Gerald L.

    2014-01-01

    Leptospira interrogans is a global zoonotic pathogen and is the causative agent of leptospirosis, an endemic disease of humans and animals worldwide. There is limited understanding of leptospiral pathogenesis; therefore, further elucidation of the mechanisms involved would aid in vaccine development and the prevention of infection. HtpG (high-temperature protein G) is the bacterial homolog to the highly conserved molecular chaperone Hsp90 and is important in the stress responses of many bacteria. The specific role of HtpG, especially in bacterial pathogenesis, remains largely unknown. Through the use of an L. interrogans htpG transposon insertion mutant, this study demonstrates that L. interrogans HtpG is essential for virulence in the hamster model of acute leptospirosis. Complementation of the htpG mutant completely restored virulence. Surprisingly, the htpG mutant did not appear to show sensitivity to heat or oxidative stress, phenotypes common in htpG mutants in other bacterial species. Furthermore, the mutant did not show increased sensitivity to serum complement, reduced survival within macrophages, or altered protein or lipopolysaccharide expression. The underlying cause for attenuation thus remains unknown, but HtpG is a novel leptospiral virulence factor and one of only a very small number identified to date. PMID:24366253

  8. Improving source identification of Atlanta aerosol using temperature resolved carbon fractions in positive matrix factorization

    NASA Astrophysics Data System (ADS)

    Kim, Eugene; Hopke, Philip K.; Edgerton, Eric S.

    Daily integrated PM 2.5 (particulate matter ⩽2.5 μm in aerodynamic diameter) composition data including eight individual carbon fractions collected at the Jefferson Street monitoring site in Atlanta were analyzed with positive matrix factorization (PMF). Particulate carbon was analyzed using the thermal optical reflectance method that divides carbon into four organic carbon (OC), pyrolized organic carbon (OP), and three elemental carbon (EC) fractions. A total of 529 samples and 28 variables were measured between August 1998 and August 2000. PMF identified 11 sources in this study: sulfate-rich secondary aerosol I (50%), on-road diesel emissions (11%), nitrate-rich secondary aerosol (9%), wood smoke (7%), gasoline vehicle (6%), sulfate-rich secondary aerosol II (6%), metal processing (3%), airborne soil (3%), railroad traffic (3%), cement kiln/carbon-rich (2%), and bus maintenance facility/highway traffic (2%). Differences from previous studies using only the traditional OC and EC data (J. Air Waste Manag. Assoc. 53(2003a)731; Atmos Environ. (2003b)) include four traffic-related combustion sources (gasoline vehicle, on-road diesel, railroad, and bus maintenance facility) containing carbon fractions whose abundances were different between the various sources. This study indicates that the temperature resolved fractional carbon data can be utilized to enhance source apportionment study, especially with respect to the separation of diesel emissions from gasoline vehicle sources. Conditional probability functions using surface wind data and identified source contributions aid the identifications of local point sources.

  9. Dust temperature and CO ? H2 conversion factor variations in the SFR-M? plane

    NASA Astrophysics Data System (ADS)

    Magnelli, B.; Saintonge, A.; Lutz, D.; Tacconi, L. J.; Berta, S.; Bournaud, F.; Charmandaris, V.; Dannerbauer, H.; Elbaz, D.; Frster-Schreiber, N. M.; Graci-Carpio, J.; Ivison, R.; Maiolino, R.; Nordon, R.; Popesso, P.; Rodighiero, G.; Santini, P.; Wuyts, S.

    2012-12-01

    Deep Herschel PACS/SPIRE imaging and 12CO(2-1) line luminosities from the IRAM Plateau de Bure Interferometer are combined for a sample of 17 galaxies at z > 1 from the GOODS-N field. The sample includes galaxies both on and above the main sequence (MS) traced by star-forming galaxies in the SFR-M? plane. The far-infrared data are used to derive dust masses, Mdust, following the Draine & Li (2007, ApJ, 657, 810) models. Combined with an empirical prescription for the dependence of the gas-to-dust ratio on metallicity (?GDR(?0)), the CO luminosities and Mdust values are used to derive for each galaxy the CO-to-H2 conversion factor, ?CO. Like in the local Universe, the value of ?CO is a factor of ~5 smaller in starbursts compared to normal star-forming galaxies (SFGs). We additionally uncover a relation between ?CO and dust temperature (Tdust; ?CO decreasing with increasing Tdust) as obtained from modified blackbody fits to the far-infrared data. While the absolute normalization of the ?CO(Tdust) relation is uncertain, the global trend is robust against possible systematic biases in the determination of Mdust, ?GDR(?0) or metallicity. Although we cannot formally distinguish between a step and a smooth evolution of ?CO with the dust temperature, we can unambiguously conclude that in galaxies of near-solar metallicity, a critical value of Tdust = 30 K can be used to determine whether the appropriate ?CO is closer to the "starburst" value (1.0 M? (K km s-1 pc2)-1, when Tdust > 30 K) or closer to the Galactic value (4.35 M? (K km s-1 pc2)-1, when Tdust < 30 K). This indicator has the great advantage of being less subjective than visual morphological classifications of mergers/SFGs, which can be difficult at high z because of the clumpy nature of SFGs. Using Tdust to select the appropriate ?CO is also more indicative of ISM conditions than a fixed LIR criterion. In the absence of far-infrared data, the offset of a galaxy from the star formation main sequence (i.e., ?log (SSFR)MS = log [SSFR(galaxy)/SSFRMS(M?,z)]) can be used to identify galaxies requiring the use of an ?CO conversion factor lower than the Galactic value (i.e., when ?log (SSFR)MS ? 0.3 dex). Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). Based also on observations carried out by the Herschel space observatory. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  10. Influence of sky view factor on outdoor thermal environment and physiological equivalent temperature.

    PubMed

    He, Xiaodong; Miao, Shiguang; Shen, Shuanghe; Li, Ju; Zhang, Benzhi; Zhang, Ziyue; Chen, Xiujie

    2015-03-01

    Sky view factor (SVF), which is an indicator of urban canyon geometry, affects the surface energy balance, local air circulation, and outdoor thermal comfort. This study focused on a continuous and long-term meteorological observation system to investigate the effects of SVF on outdoor thermal conditions and physiological equivalent temperature (PET) in the central business district (CBD) of Beijing (which is located within Chaoyang District), specifically addressed current knowledge gaps for SVF-PET relationships in cities with typical continental/microthermal climates. An urban sub-domain scale model and the RayMan model were used to diagnose wind fields and to calculate SVF and long-term PET, respectively. Analytical results show that the extent of shading contributes to variations in thermal perception distribution. Highly shaded areas (SVF <0.3) typically exhibit less frequent hot conditions during summer, while enduring longer periods of cold discomfort in winter than moderately shaded areas (0.3< SVF <0.5) and slightly shaded areas (SVF >0.5), and vice versa. Because Beijing has a monsoon-influenced humid continental climate with hot summers and long, cold, windy, and dry winters, a design project that ideally provides moderate shading should be planned to balance hot discomfort in summer and cold discomfort in winter, which effectively prolongs the comfort periods in outdoor spaces throughout the entire year. This research indicate that climate zone characteristics, urban environmental conditions, and thermal comfort requirements of residents must be accounted for in local-scale scientific planning and design, i.e., for urban canyon streets and residential estates. PMID:24842520

  11. Influence of sky view factor on outdoor thermal environment and physiological equivalent temperature

    NASA Astrophysics Data System (ADS)

    He, Xiaodong; Miao, Shiguang; Shen, Shuanghe; Li, Ju; Zhang, Benzhi; Zhang, Ziyue; Chen, Xiujie

    2015-03-01

    Sky view factor (SVF), which is an indicator of urban canyon geometry, affects the surface energy balance, local air circulation, and outdoor thermal comfort. This study focused on a continuous and long-term meteorological observation system to investigate the effects of SVF on outdoor thermal conditions and physiological equivalent temperature (PET) in the central business district (CBD) of Beijing (which is located within Chaoyang District), specifically addressed current knowledge gaps for SVF-PET relationships in cities with typical continental/microthermal climates. An urban sub-domain scale model and the RayMan model were used to diagnose wind fields and to calculate SVF and long-term PET, respectively. Analytical results show that the extent of shading contributes to variations in thermal perception distribution. Highly shaded areas (SVF <0.3) typically exhibit less frequent hot conditions during summer, while enduring longer periods of cold discomfort in winter than moderately shaded areas (0.3< SVF <0.5) and slightly shaded areas (SVF >0.5), and vice versa. Because Beijing has a monsoon-influenced humid continental climate with hot summers and long, cold, windy, and dry winters, a design project that ideally provides moderate shading should be planned to balance hot discomfort in summer and cold discomfort in winter, which effectively prolongs the comfort periods in outdoor spaces throughout the entire year. This research indicate that climate zone characteristics, urban environmental conditions, and thermal comfort requirements of residents must be accounted for in local-scale scientific planning and design, i.e., for urban canyon streets and residential estates.

  12. The spliceosome assembly factor GEMIN2 attenuates the effects of temperature on alternative splicing and circadian rhythms.

    PubMed

    Schlaen, Rubn Gustavo; Mancini, Estefana; Sanchez, Sabrina Elena; Perez-Santngelo, Soledad; Rugnone, Matas L; Simpson, Craig G; Brown, John W S; Zhang, Xu; Chernomoretz, Ariel; Yanovsky, Marcelo J

    2015-07-28

    The mechanisms by which poikilothermic organisms ensure that biological processes are robust to temperature changes are largely unknown. Temperature compensation, the ability of circadian rhythms to maintain a relatively constant period over the broad range of temperatures resulting from seasonal fluctuations in environmental conditions, is a defining property of circadian networks. Temperature affects the alternative splicing (AS) of several clock genes in fungi, plants, and flies, but the splicing factors that modulate these effects to ensure clock accuracy throughout the year remain to be identified. Here we show that GEMIN2, a spliceosomal small nuclear ribonucleoprotein assembly factor conserved from yeast to humans, modulates low temperature effects on a large subset of pre-mRNA splicing events. In particular, GEMIN2 controls the AS of several clock genes and attenuates the effects of temperature on the circadian period in Arabidopsis thaliana. We conclude that GEMIN2 is a key component of a posttranscriptional regulatory mechanism that ensures the appropriate acclimation of plants to daily and seasonal changes in temperature conditions. PMID:26170331

  13. The spliceosome assembly factor GEMIN2 attenuates the effects of temperature on alternative splicing and circadian rhythms

    PubMed Central

    Schlaen, Rubén Gustavo; Mancini, Estefanía; Sanchez, Sabrina Elena; Perez-Santángelo, Soledad; Rugnone, Matías L.; Simpson, Craig G.; Brown, John W. S.; Zhang, Xu; Chernomoretz, Ariel; Yanovsky, Marcelo J.

    2015-01-01

    The mechanisms by which poikilothermic organisms ensure that biological processes are robust to temperature changes are largely unknown. Temperature compensation, the ability of circadian rhythms to maintain a relatively constant period over the broad range of temperatures resulting from seasonal fluctuations in environmental conditions, is a defining property of circadian networks. Temperature affects the alternative splicing (AS) of several clock genes in fungi, plants, and flies, but the splicing factors that modulate these effects to ensure clock accuracy throughout the year remain to be identified. Here we show that GEMIN2, a spliceosomal small nuclear ribonucleoprotein assembly factor conserved from yeast to humans, modulates low temperature effects on a large subset of pre-mRNA splicing events. In particular, GEMIN2 controls the AS of several clock genes and attenuates the effects of temperature on the circadian period in Arabidopsis thaliana. We conclude that GEMIN2 is a key component of a posttranscriptional regulatory mechanism that ensures the appropriate acclimation of plants to daily and seasonal changes in temperature conditions. PMID:26170331

  14. RECIPES FOR WRITING ALGORITHMS FOR ATMOSPHERIC CORRECTIONS AND TEMPERATURE/EMISSIVITY SEPARATIONS IN THE THERMAL REGIME FOR A MULTI-SPECTRAL SENSOR

    SciTech Connect

    C. BOREL; W. CLODIUS

    2001-04-01

    This paper discusses the algorithms created for the Multi-spectral Thermal Imager (MTI) to retrieve temperatures and emissivities. Recipes to create the physics based water temperature retrieval, emissivity of water surfaces are described. A simple radiative transfer model for multi-spectral sensors is developed. A method to create look-up-tables and the criterion of finding the optimum water temperature are covered. Practical aspects such as conversion from band-averaged radiances to brightness temperatures and effects of variations in the spectral response on the atmospheric transmission are discussed. A recipe for a temperature/emissivity separation algorithm when water surfaces are present is given. Results of retrievals of skin water temperatures are compared with in-situ measurements of the bulk water temperature at two locations are shown.

  15. Genotype-specific risk factors for Staphylococcus aureus in Swiss dairy herds with an elevated yield-corrected herd somatic cell count.

    PubMed

    Berchtold, B; Bodmer, M; van den Borne, B H P; Reist, M; Graber, H U; Steiner, A; Boss, R; Wohlfender, F

    2014-01-01

    Bovine mastitis is a frequent problem in Swiss dairy herds. One of the main pathogens causing significant economic loss is Staphylococcus aureus. Various Staph. aureus genotypes with different biological properties have been described. Genotype B (GTB) of Staph. aureus was identified as the most contagious and one of the most prevalent strains in Switzerland. The aim of this study was to identify risk factors associated with the herd-level presence of Staph. aureus GTB and Staph. aureus non-GTB in Swiss dairy herds with an elevated yield-corrected herd somatic cell count (YCHSCC). One hundred dairy herds with a mean YCHSCC between 200,000 and 300,000cells/mL in 2010 were recruited and each farm was visited once during milking. A standardized protocol investigating demography, mastitis management, cow husbandry, milking system, and milking routine was completed during the visit. A bulk tank milk (BTM) sample was analyzed by real-time PCR for the presence of Staph. aureus GTB to classify the herds into 2 groups: Staph. aureus GTB-positive and Staph. aureus GTB-negative. Moreover, quarter milk samples were aseptically collected for bacteriological culture from cows with a somatic cell count ?150,000cells/mL on the last test-day before the visit. The culture results allowed us to allocate the Staph. aureus GTB-negative farms to Staph. aureus non-GTB and Staph. aureus-free groups. Multivariable multinomial logistic regression models were built to identify risk factors associated with the herd-level presence of Staph. aureus GTB and Staph. aureus non-GTB. The prevalence of Staph. aureus GTB herds was 16% (n=16), whereas that of Staph. aureus non-GTB herds was 38% (n=38). Herds that sent lactating cows to seasonal communal pastures had significantly higher odds of being infected with Staph. aureus GTB (odds ratio: 10.2, 95% CI: 1.9-56.6), compared with herds without communal pasturing. Herds that purchased heifers had significantly higher odds of being infected with Staph. aureus GTB (rather than Staph. aureus non-GTB) compared with herds without purchase of heifers. Furthermore, herds that did not use udder ointment as supportive therapy for acute mastitis had significantly higher odds of being infected with Staph. aureus GTB (odds ratio: 8.5, 95% CI: 1.6-58.4) or Staph. aureus non-GTB (odds ratio: 6.1, 95% CI: 1.3-27.8) than herds that used udder ointment occasionally or regularly. Herds in which the milker performed unrelated activities during milking had significantly higher odds of being infected with Staph. aureus GTB (rather than Staph. aureus non-GTB) compared with herds in which the milker did not perform unrelated activities at milking. Awareness of 4 potential risk factors identified in this study guides implementation of intervention strategies to improve udder health in both Staph. aureus GTB and Staph. aureus non-GTB herds. PMID:24881801

  16. BTPS correction with dynamic spirometers.

    PubMed

    Forche, G; Harnoncourt, K; Stadlober, E; Zenker, G

    1986-01-01

    In order to determine the requirements for a proper temperature correction of expired volumes, the temperature of the expired air in the bellows of a dynamic spirometer (Vitalograph) was measured in 10 and 5 subjects at 24 and 12.2 degrees C ambient temperature, respectively. During the short period of forced expiration there was a significant temperature decrease, which showed a linear relationship to the ambient temperature. Temperature differences up to 12-15% occurred within seconds; consequently, the values obtained in bellows-type spirometers for FEV1 and FVC have to be corrected to BTPS at room temperature. There was no correlation between the degree of temperature decrease and the magnitude of expiratory volume. For routine clinical work it suffices to use the room temperature as the variable. PMID:3715213

  17. Temperature

    NASA Technical Reports Server (NTRS)

    Berenson, P. J.; Robertson, W. G.

    1973-01-01

    The problems in human comfort in heat stress are emphasized, with less emphasis placed upon cold exposure problems. Physiological parameters related to human thermal interactions are discussed, as well as data concerning thermal protective clothing. The energy balance equation, heat transfer equation, thermal comfort, heat stress, and cold stress are also considered. A two node model of human temperature regulation in FORTRAN is appended.

  18. Aureolegraph internal scattering correction.

    PubMed

    DeVore, John; Villanucci, Dennis; LePage, Andrew

    2012-11-20

    Two methods of determining instrumental scattering for correcting aureolegraph measurements of particulate solar scattering are presented. One involves subtracting measurements made with and without an external occluding ball and the other is a modification of the Langley Plot method and involves extrapolating aureolegraph measurements collected through a large range of solar zenith angles. Examples of internal scattering correction determinations using the latter method show similar power-law dependencies on scattering, but vary by roughly a factor of 8 and suggest that changing aerosol conditions during the determinations render this method problematic. Examples of corrections of scattering profiles using the former method are presented for a range of atmospheric particulate layers from aerosols to cumulus and cirrus clouds. PMID:23207299

  19. Predictive factors for obtaining a correct therapeutic range using antivitamin K anticoagulants: a tertiary center experience of patient adherence to anticoagulant therapy

    PubMed Central

    Jurcu?, Ruxandra; Militaru, Sebastian; Geavlete, Oliviana; Dr?gotoiu, Nic; Sipo?, Sergiu; Ro?ulescu, R?zvan; Ginghin?, Carmen; Jurcu?, Ciprian

    2015-01-01

    Background Patient adherence is an essential factor in obtaining efficient oral anticoagulation using vitamin K antagonists (VKAs), a situation with a narrow therapeutic window. Therefore, patient education and awareness are crucial for good management. Auditing the current situation would help to identify the magnitude of the problem and to build tailored education programs for these patients. Methods This study included 68 hospitalized chronically anticoagulated patients (mean age 62.613.1 years; males, 46%) who responded to a 26-item questionnaire to assess their knowledge on VKA therapy management. Laboratory and clinical data were used to determine the international normalized ratio (INR) at admission, as well as to calculate CHA2DS2-VASC and HAS-BLED scores for patients with atrial fibrillation. Results The majority of patients (62%) were receiving VKA for atrial fibrillation, the others for a mechanical prosthesis and previous thromboembolic disease or stroke. In the atrial fibrillation group, the mean CHA2DS2-VASC score was 3.11.5, while the average HAS-BLED score was 1.81.2. More than half of the patients (53%) had an INR outside of the therapeutic range at admission, with the majority (43%) having a low INR. A correct INR value was predicted by education level (higher education) and the diagnostic indication (patients with mechanical prosthesis being best managed). Patients presenting with a therapeutic INR had a trend toward longer treatment duration than those outside the therapeutic range (6272 months versus 3635 months, respectively, P=0.06). There was no correlation between INR at admission and the patients living conditions, INR monitoring frequency, and bleeding history. Conclusion In a tertiary cardiology center, more than half of patients receiving VKAs are admitted with an INR falling outside the therapeutic range, irrespective of the bleeding or embolic risk. Patients with a mechanical prosthesis and complex antithrombotic regimens appear to be the most careful with INR monitoring, especially if they have a higher level of education. Identifying patient groups with the lowest time interval spent in the therapeutic range could help attending physicians educate patients focusing on specific awareness issues. PMID:26388689

  20. Influence of some psychological factors on temperature dynamics of human hands

    NASA Astrophysics Data System (ADS)

    Koreneva, L. G.; Apenisheva, N. P.; Zakharov, Pavel V.; Markov, A. G.

    1993-11-01

    Temperature dynamics of the hands of human subjects was investigated by means of dynamical thermography and shown to depend on the personality and psychological conditions of the subjects. For neurotic personalities, especially under stress, the temperature is shown not to change at all in most cases. Stress resistant `independent' persons show very stable dynamics with relatively small temperature changes (about 2 degrees). The dependence of temperature patterns of `intermediate,' or `active,' personalities on the conditions of stress, mental concentration, and so on, is discussed.

  1. Overexpression of sigma factor SigB improves temperature and butanol tolerance of Synechocystis sp. PCC6803.

    PubMed

    Kaczmarzyk, Danuta; Anfelt, Josefine; Srnegrim, Amanda; Hudson, Elton P

    2014-07-20

    Among phenotypes of interest for an industrial cyanobacteria host are improved tolerance to temperature, salt, and solvent stress. Cellular responses to many stresses are controlled by the network of sensory receptors and downstream regulatory proteins. We applied transcription factor engineering to Synechocystis and tested mutant strains for tolerance to temperature and the biofuel 1-butanol. Histidine kinases (Hik), response regulators (Rre), and an RNA polymerase sigma factor (SigB) were overexpressed or deleted. Overexpression of SigB increased both temperature and butanol tolerance and lowered the intracellular concentration of reactive oxygen species. This report demonstrates that alteration of regulatory proteins in a cyanobacterium can be a useful tool to improve stress tolerance. PMID:24800959

  2. An improved temperature index model for alpine glaciers using derived degree-day factors from climatic inputs

    NASA Astrophysics Data System (ADS)

    Keeler, D. G.; Havens, A. P.; Rupper, S.; Christensen, W. F.

    2013-12-01

    Glacier melt rates are strongly affected by minor perturbations in climatic systems. Quantifying changes in glacier melt rates is therefore important, particularly in areas where melt-water contributes to hydroelectric power generation, irrigation, or flood risks. Several methods currently exist for modeling glacier melt rates, but one widely used method is temperature index modeling, also called positive degree-day modeling. This model is often applied due to its simplicity and small number of input variables, but it still depends on an empirically-measured scaling constant (the degree-day factor). These degree-day factors can vary by a factor of five from one glacier to the next, complicating the applicability of the approach to new regions, or to different time periods. Previous work suggests the degree-day factor may be a function of the surface albedo, solar radiation, and near-surface air temperature. Thus, it is possible the degree-day factor itself is predictable. In this study we present a method to derive these melt factors directly from easily obtained climatic variables, thus allowing for the ready application of temperature index modeling to a much wider suite of glaciers with greater accuracy. We used a full energy-balance model to calculate possible degree-day factors over the full range of climate conditions commonly encountered with alpine glaciers. We then constructed a statistical emulator (a linear model which considers numerous interactions and polynomial effects) using select climate variables (insolation, positive degree-days, and albedo) as inputs. The statistical model is tuned using the energy-balance output as training data. The model skill will be tested against a suite of empirically-derived degree-day factors. These results would allow for the application of more accurate glacier melt models with quantified uncertainties to under-sampled glacial regions and paleoclimate reconstructions.

  3. A CORRECTION.

    PubMed

    Johnson, D

    1940-03-22

    IN a recently published volume on "The Origin of Submarine Canyons" the writer inadvertently credited to A. C. Veatch an excerpt from a submarine chart actually contoured by P. A. Smith, of the U. S. Coast and Geodetic Survey. The chart in question is Chart IVB of Special Paper No. 7 of the Geological Society of America entitled "Atlantic Submarine Valleys of the United States and the Congo Submarine Valley, by A. C. Veatch and P. A. Smith," and the excerpt appears as Plate III of the volume fist cited above. In view of the heavy labor involved in contouring the charts accompanying the paper by Veatch and Smith and the beauty of the finished product, it would be unfair to Mr. Smith to permit the error to go uncorrected. Excerpts from two other charts are correctly ascribed to Dr. Veatch. PMID:17839404

  4. A hypothesis about factors that affect maximum stream temperatures across montane landscapes

    USGS Publications Warehouse

    Isaak, D.J.; Hubert, W.A.

    2001-01-01

    Temperature is an important variable structuring lotic biotas, but little is known about how montane landscapes function to determine stream temperatures. We developed an a priori hypothesis that was used to predict how watershed elements would interact to affect stream temperatures. The hypothesis was tested in a series of path analyses using temperature data from 26 sites on second-order to fourth-order streams across a fifth-order Rocky Mountain watershed. Based on the performance of the first hypothesis, two revised versions of the hypothesis were developed and tested that proved to be more accurate than the original hypothesis. The most plausible of the revised hypotheses accounted for 82 percent of the variation in maximum stream temperature, had a predicted data structure that did not deviate from the empirical data structure, and was the most parsimonious. The final working hypothesis suggested that stream temperature maxima were directly controlled by a large negative effect from mean basin elevation (direct effect = -0.57, p < 0.01) and smaller effects from riparian tree abundance (direct effect = -0.28, p = 0.03), and cattle density (direct effect = 0.24, p = 0.05). Watershed slope, valley constraint, and the abundance of grass across a watershed also affected temperature maxima, but these effects were indirect and mediated through cattle density and riparian trees. Three variables included in the a priori hypothesis - watershed aspect, stream width, and watershed size - had negligible effects on maximum stream temperatures and were omitted from the final working hypothesis.

  5. Effect of design factors on surface temperature and wear in disk brakes

    NASA Technical Reports Server (NTRS)

    Santini, J. J.; Kennedy, F. E.; Ling, F. F.

    1976-01-01

    The temperatures, friction, wear and contact conditions that occur in high energy disk brakes are studied. Surface and near surface temperatures were monitored at various locations in a caliper disk brake during drag type testing, with friction coefficient and wear rates also being determined. The recorded transient temperature distributions in the friction pads and infrared photographs of the rotor disk surface both showed that contact at the friction surface was not uniform, with contact areas constantly shifting due to nonuniform thermal expansion and wear. The effect of external cooling and of design modifications on friction, wear and temperatures was also investigated. It was found that significant decreases in surface temperature and in wear rate can be achieved without a reduction in friction either by slotting the contacting face of the brake pad or by modifying the design of the pad support to improve pad compliance. Both design changes result in more uniform contact conditions on the friction surface.

  6. Dominant factors affecting temperature rise in simulations of human thermoregulation during RF exposure

    NASA Astrophysics Data System (ADS)

    Laakso, Ilkka; Hirata, Akimasa

    2011-12-01

    Numerical models of the human thermoregulatory system can be used together with realistic voxel models of the human anatomy to simulate the body temperature increases caused by the power absorption from radio-frequency electromagnetic fields. In this paper, the Pennes bioheat equation with a thermoregulatory model is used for calculating local peak temperatures as well as the body-core-temperature elevation in a realistic human body model for grounded plane-wave exposures at frequencies 39, 800 and 2400 MHz. The electromagnetic power loss is solved by the finite-difference time-domain (FDTD) method, and the discretized bioheat equation is solved by the geometric multigrid method. Human thermoregulatory models contain numerous thermophysiological and computational parameterssome of which may be subject to considerable uncertaintythat affect the simulated core and local temperature elevations. The goal of this paper is to find how greatly the computed temperature is influenced by changes in various modelling parameters, such as the skin blood flow rate, models for vasodilation and sweating, and clothing and air movement. The results show that the peak temperature rises are most strongly affected by the modelling of tissue blood flow and its temperature dependence, and mostly unaffected by the central control mechanism for vasodilation and sweating. Almost the opposite is true for the body-core-temperature rise, which is however typically greatly lower than the peak temperature rise. It also seems that ignoring the thermoregulation and the blood temperature increase is a good approximation when the local 10 g averaged specific absorption rate is smaller than 10 W kg-1.

  7. Homeothermy in neonatal chicks exposed to low environmental temperature with or without intracerebroventricular administration of corticotropin-releasing factor.

    PubMed

    Mujahid, Ahmad; Furuse, Mitsuhiro

    2008-09-01

    To determine the mechanism of sensitivity to low-temperature exposure (20 degrees C for 3h) and corticotropin-releasing factor (CRF) induced increased homeothermy, we investigated gene transcripts of putative thermogenic proteins and mitochondrial fatty acid (FA)-oxidation enzymes in neonatal chicks. The hypothalamic-pituitary-adrenal (HPA) axis in low-temperature-exposed neonatal chicks was activated by central administration of CRF. Neonatal chicks showed hypothermia on exposure to low-temperature, with no enhancement of HPA axis and gene transcripts of avian adenine nucleotide translocator, avian uncoupling protein, avian peroxisome-proliferator-activated receptor-gamma co-activator-1alpha, and mitochondrial FA transport and oxidation enzymes in vital organs. However, central administration of CRF activated the HPA axis under low environmental temperature and induced increased homeothermy that was associated with the enhancement of gene transcripts and activities of mitochondrial FA-oxidation enzymes in the liver and heart. PMID:18691576

  8. Conductivity Cell Thermal Inertia Correction Revisited

    NASA Astrophysics Data System (ADS)

    Eriksen, C. C.

    2012-12-01

    Salinity measurements made with a CTD (conductivity-temperature-depth instrument) rely on accurate estimation of water temperature within their conductivity cell. Lueck (1990) developed a theoretical framework for heat transfer between the cell body and water passing through it. Based on this model, Lueck and Picklo (1990) introduced the practice of correcting for cell thermal inertia by filtering a temperature time series using two parameters, an amplitude ? and a decay time constant ?, a practice now widely used. Typically these two parameters are chosen for a given cell configuration and internal flushing speed by a statistical method applied to a particular data set. Here, thermal inertia correction theory has been extended to apply to flow speeds spanning well over an order of magnitude, both within and outside a conductivity cell, to provide predictions of ? and ? from cell geometry and composition. The extended model enables thermal inertia correction for the variable flows encountered by conductivity cells on autonomous gliders and floats, as well as tethered platforms. The length scale formed as the product of cell encounter speed of isotherms, ?, and ? can be used to gauge the size of the temperature correction for a given thermal stratification. For cells flushed by dynamic pressure variation induced by platform motion, this length varies by less than a factor of 2 over more than a decade of speed variation. The magnitude of correction for free-flow flushed sensors is comparable to that of pumped cells, but at an order of magnitude in energy savings. Flow conditions around a cell's exterior are found to be of comparable importance to thermal inertia response as flushing speed. Simplification of cell thermal response to a single normal mode is most valid at slow speed. Error in thermal inertia estimation arises from both neglect of higher modes and numerical discretization of the correction scheme, both of which can be easily quantified. Consideration of thermal inertia correction enables assessment of various CTD sampling schemes. Spot sampling by pumping a cell intermittently provides particular challenges, and may lead to biases in inferred salinity that are comparable to climate signals reported from profiling float arrays.

  9. In Situ Mosaic Brightness Correction

    NASA Technical Reports Server (NTRS)

    Deen, Robert G.; Lorre, Jean J.

    2012-01-01

    In situ missions typically have pointable, mast-mounted cameras, which are capable of taking panoramic mosaics comprised of many individual frames. These frames are mosaicked together. While the mosaic software applies radiometric correction to the images, in many cases brightness/contrast seams still exist between frames. This is largely due to errors in the radiometric correction, and the absence of correction for photometric effects in the mosaic processing chain. The software analyzes the overlaps between adjacent frames in the mosaic and determines correction factors for each image in an attempt to reduce or eliminate these brightness seams.

  10. Resource Supply Overrides Temperature as a Controlling Factor of Marine Phytoplankton Growth

    PubMed Central

    Marañón, Emilio; Cermeño, Pedro; Huete-Ortega, María; López-Sandoval, Daffne C.; Mouriño-Carballido, Beatriz; Rodríguez-Ramos, Tamara

    2014-01-01

    The universal temperature dependence of metabolic rates has been used to predict how ocean biology will respond to ocean warming. Determining the temperature sensitivity of phytoplankton metabolism and growth is of special importance because this group of organisms is responsible for nearly half of global primary production, sustains most marine food webs, and contributes to regulate the exchange of CO2 between the ocean and the atmosphere. Phytoplankton growth rates increase with temperature under optimal growth conditions in the laboratory, but it is unclear whether the same degree of temperature dependence exists in nature, where resources are often limiting. Here we use concurrent measurements of phytoplankton biomass and carbon fixation rates in polar, temperate and tropical regions to determine the role of temperature and resource supply in controlling the large-scale variability of in situ metabolic rates. We identify a biogeographic pattern in phytoplankton metabolic rates, which increase from the oligotrophic subtropical gyres to temperate regions and then coastal waters. Variability in phytoplankton growth is driven by changes in resource supply and appears to be independent of seawater temperature. The lack of temperature sensitivity of realized phytoplankton growth is consistent with the limited applicability of Arrhenius enzymatic kinetics when substrate concentrations are low. Our results suggest that, due to widespread resource limitation in the ocean, the direct effect of sea surface warming upon phytoplankton growth and productivity may be smaller than anticipated. PMID:24921945

  11. Resource supply overrides temperature as a controlling factor of marine phytoplankton growth.

    PubMed

    Maran, Emilio; Cermeo, Pedro; Huete-Ortega, Mara; Lpez-Sandoval, Daffne C; Mourio-Carballido, Beatriz; Rodrguez-Ramos, Tamara

    2014-01-01

    The universal temperature dependence of metabolic rates has been used to predict how ocean biology will respond to ocean warming. Determining the temperature sensitivity of phytoplankton metabolism and growth is of special importance because this group of organisms is responsible for nearly half of global primary production, sustains most marine food webs, and contributes to regulate the exchange of CO2 between the ocean and the atmosphere. Phytoplankton growth rates increase with temperature under optimal growth conditions in the laboratory, but it is unclear whether the same degree of temperature dependence exists in nature, where resources are often limiting. Here we use concurrent measurements of phytoplankton biomass and carbon fixation rates in polar, temperate and tropical regions to determine the role of temperature and resource supply in controlling the large-scale variability of in situ metabolic rates. We identify a biogeographic pattern in phytoplankton metabolic rates, which increase from the oligotrophic subtropical gyres to temperate regions and then coastal waters. Variability in phytoplankton growth is driven by changes in resource supply and appears to be independent of seawater temperature. The lack of temperature sensitivity of realized phytoplankton growth is consistent with the limited applicability of Arrhenius enzymatic kinetics when substrate concentrations are low. Our results suggest that, due to widespread resource limitation in the ocean, the direct effect of sea surface warming upon phytoplankton growth and productivity may be smaller than anticipated. PMID:24921945

  12. Experimental determination of field factors (\\Omega _{{{Q}_{\\text{clin}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{clin}}},{{f}_{\\text{msr}}}} ) for small radiotherapy beams using the daisy chain correction method

    NASA Astrophysics Data System (ADS)

    Lrraga-Gutirrez, Jos Manuel

    2015-08-01

    Recently, Alfonso et al proposed a new formalism for the dosimetry of small and non-standard fields. The proposed new formalism is strongly based on the calculation of detector-specific beam correction factors by Monte Carlo simulation methods, which accounts for the difference in the response of the detector between the small and the machine specific reference field. The correct calculation of the detector-specific beam correction factors demands an accurate knowledge of the linear accelerator, detector geometry and composition materials. The present work shows that the field factors in water may be determined experimentally using the daisy chain correction method down to a field size of 1?cm????1?cm for a specific set of detectors. The detectors studied were: three mini-ionization chambers (PTW-31014, PTW-31006, IBA-CC01), three silicon-based diodes (PTW-60018, IBA-SFD and IBA-PFD) and one synthetic diamond detector (PTW-60019). Monte Carlo simulations and experimental measurements were performed for a 6 MV photon beam at 10?cm depth in water with a source-to-axis distance of 100?cm. The results show that the differences between the experimental and Monte Carlo calculated field factors are less than 0.5%with the exception of the IBA-PFDfor field sizes between 1.5?cm????1.5?cm and 5?cm????5?cm. For the 1?cm????1?cm field size, the differences are within 2%. By using the daisy chain correction method, it is possible to determine measured field factors in water. The results suggest that the daisy chain correction method is not suitable for measurements performed with the IBA-PFD detector. The latter is due to the presence of tungsten powder in the detector encapsulation material. The use of Monte Carlo calculated k{{Q\\text{clin}},{{Q}\\text{msr}}}{{f\\text{clin}},{{f}\\text{msr}}} is encouraged for field sizes less than or equal to 1?cm????1?cm for the dosimeters used in this work.

  13. Factors affecting temperature variation and habitat use in free-ranging diamondback terrapins.

    PubMed

    Akins, C D; Ruder, C D; Price, S J; Harden, L A; Gibbons, J W; Dorcas, M E

    2014-08-01

    Measuring the thermal conditions of aquatic reptiles with temperature dataloggers is a cost-effective way to study their behavior and habitat use. Temperature dataloggers are a particularly useful and informative approach to studying organisms such as the estuarine diamondback terrapin (Malaclemys terrapin) that inhabits a dynamic environment often inaccessible to researchers. We used carapace-mounted dataloggers to measure hourly carapace temperature (Tc) of free-ranging terrapins in South Carolina from October 2007 to 2008 to examine the effects of month, sex, creek site, and tide on Tc and to determine the effects of month, sex, and time of day on terrapin basking frequency. Simultaneous measurements of environmental temperatures (Te; shallow mud, deep mud, water) allowed us to make inferences about terrapin microhabitat use. Terrapin Tc differed significantly among months and creek and between sexes. Terrapin microhabitat use also varied monthly, with shallow mud temperature being the best predictor of Tc November-March and water temperature being the best predictor of Tc April-October. Terrapins basked most frequently in spring and fall and males basked more frequently than females. Our study contributes to a fuller understanding of terrapin thermal biology and provides support for using dataloggers to investigate behavior and habitat use of aquatic ectotherms inhabiting dynamic environments. PMID:25086975

  14. Local tissue temperature: a critical factor in the pathogenesis of bovid herpesvirus 2.

    PubMed Central

    Letchworth, G J; Carmichael, L E

    1984-01-01

    The effect of local tissue temperature on bovid herpesvirus 2 lesions in bovine skin was studied. Two areas of thoracic skin were multiply inoculated with virus and maintained at different temperatures; one above and the other below the rectal temperature of the animal. An entire inoculation site was removed daily from each area and subjected to virus, viral antigen, and interferon titrations and both light and electron microscopic examinations. Lesions in cold skin appeared sooner after inoculation, were larger and deeper, contained more infectious virus, viral antigen, and interferon, and lasted longer than lesions in hot skin. Differences in viral titers greater than 10(9) 50% tissue culture infective doses per gram were measured on postinfection days 5 to 9. These studies have demonstrated for the first time that temperature effects on viral pathogenesis may operate at the local level rather than by systemic modification of immune responses. The results also suggest that despite the presence of virus in internal organs of bovid herpesvirus 2-infected cattle and the ability of bovid herpesvirus 2 to replicate to very high titers in these tissues in vitro, only the skin is cool enough to permit substantial viral replication and dermal lesions in vivo. The observed restriction of bovid herpesvirus 2 skin lesions to the udder and teats of cattle and the restriction of outbreaks of disease to months when the temperature is declining may also be reflections of this temperature sensitivity. Images PMID:6199299

  15. Empirical mode decomposition based dynamic error correction in SS covered 62.5/125 ?m optical fiber based distributed temperature sensor

    NASA Astrophysics Data System (ADS)

    Saxena, Manoj Kumar; Raju, S. D. V. S. Jagannadha; Arya, R.; Pachori, R. B.; Ravindranath, S. V. G.; Kher, S.; Oak, S. M.

    2015-04-01

    The design and implementation of empirical mode decomposition (EMD) based preprocessor for backscattered spontaneous Raman anti-Stokes (AS) and Stokes (St) signals obtained from a stainless steel (SS) covered, 62.5/125 ?m optical fiber based distributed temperature sensor is presented. The preprocessor dynamically minimizes the error in temperature measurement caused by the difference in attenuation to AS and St signals offered by the optical fiber. Simultaneous denoising of AS and St signals obtained by the EMD based preprocessor yields better signal to noise ratio (SNR) of these signals and allows reduced error in temperature measurement. The EMD based technique is much better than previously reported techniques in terms of simplicity and automation. Automated and dynamic self calibration of distributed temperature sensor is also possible with the proposed preprocessor in an easier way. The use of proposed preprocessor has been demonstrated to develop an optical fiber based distributed temperature sensor with an accuracy of 2.5 C in a temperature range of 25-105 C over a sensing length of 90 m with a spatial resolution of 1 m. The developed system uses a rugged stainless steel (SS) covered 62.5/125 ?m Multimode optical fiber. SS covering on the fiber makes it easier and safer to install the sensing fiber in critical field locations where normal sensing fiber cannot be used.

  16. Psychophysics of a Nociceptive Test in the Mouse: Ambient Temperature as a Key Factor for Variation

    PubMed Central

    Pincedé, Ivanne; Pollin, Bernard; Meert, Theo; Plaghki, Léon; Le Bars, Daniel

    2012-01-01

    Background The mouse is increasingly used in biomedical research, notably in behavioral neurosciences for the development of tests or models of pain. Our goal was to provide the scientific community with an outstanding tool that allows the determination of psychophysical descriptors of a nociceptive reaction, which are inaccessible with conventional methods: namely the true threshold, true latency, conduction velocity of the peripheral fibers that trigger the response and latency of the central decision-making process. Methodology/Principal Findings Basically, the procedures involved heating of the tail with a CO2 laser, recording of tail temperature with an infrared camera and stopping the heating when the animal reacted. The method is based mainly on the measurement of three observable variables, namely the initial temperature, the heating rate and the temperature reached at the actual moment of the reaction following random variations in noxious radiant heat. The initial temperature of the tail, which itself depends on the ambient temperature, very markedly influenced the behavioral threshold, the behavioral latency and the conduction velocity of the peripheral fibers but not the latency of the central decision-making. Conclusions/Significance We have validated a psychophysical approach to nociceptive reactions for the mouse, which has already been described for rats and Humans. It enables the determination of four variables, which contribute to the overall latency of the response. The usefulness of such an approach was demonstrated by providing new fundamental findings regarding the influence of ambient temperature on nociceptive processes. We conclude by challenging the validity of using as “pain index" the reaction time of a behavioral response to an increasing heat stimulus and emphasize the need for a very careful control of the ambient temperature, as a prevailing environmental source of variation, during any behavioral testing of mice. PMID:22629325

  17. Energy driven cascade recognition for selective detection of nucleic acids with high discrimination factor at room temperature.

    PubMed

    Zhang, Zhang; Li, Jun Long; Yao, Juan; Wang, Ting; Yin, Dan; Xiang, Yu; Chen, Zhongping; Xie, Guoming

    2016-05-15

    In this article, we demonstrated a cascade recognition strategy for the detection of single strand nucleic acid with high discrimination factor at room temperature. The cascade recognition strategy contains a toehold mediated strand displacement and a double-toehold mediated double strand displacement reaction, thus enable the high ability to discern point mutation of target. The discrimination factor of the model target is between 45 and 109, with the medium of 70. This strategy is homogeneous, easy operation, enzyme-free, isothermal, and can be easily adapted to high-throughput devices without the need of designing complicated instruments. PMID:26745796

  18. Ambient temperature: a factor affecting performance and physiological response of broiler chickens

    NASA Astrophysics Data System (ADS)

    Donkoh, A.

    1989-12-01

    An experiment was conducted to elucidate the influence of four constant ambient temperatures (20, 25, 30 and 35C) on the performance and physiological reactions of male commercial broiler chicks from 3 to 7 weeks of age. A 12 h light-dark cycle was operated, while relative humidity and air circulation were not controlled. Exposure of broiler chickens to the 20, 25, 30 and 35C treatments showed highly significant ( P<0.0001) depression in growth rate, food intake and efficiency of food utilization, and a significant increase in water consumption for the 30 and 35C groups. Mortality was, however, not affected by the temperature treatments. Changes in physiological status, such as increased rectal temperatures, decreased concentration of red blood cells, haemoglobin, haematocrit, and total plasma protein were observed in birds housed in the higher temperature (30 and 35C) environments. Moreover, in these broiler chickens, there was an increased blood glucose concentration and a decreased thyroid gland weight. These results indicate that continuous exposure of broiler chickens to high ambient temperatures markedly affects their performance and physiological response.

  19. Energy factors and temperature distribution in insulated built-up roofs. Technical note July 1977-January 1980

    SciTech Connect

    Keeton, J.R.; Alumbaugh, R.L.

    1981-02-01

    Surface temperatures of 4-ply built-up roofs insulated with (1) 1 inch of perlite (R = 2.8) and 2-1/2 inches of urethane (R = 19.2) and (2) 1 inch of urethane (R = 7.1) and 1-7/8 inches of glass fiber (R = 7.7) are presented. Energy factors are shown in terms of temperature-time areas defined as solar heat response, cooling (heating) required, radiative cooling, and insulation efficiency. Results indicate that for a black surface, solar heat response is significantly higher in the roof portion with the higher R-value. Solar heat response is directly affected by color of surfacing; lowest to highest values were found with white, white gravel, gray gravel, aluminum-gray, and black. Recommendations are given for reducing surface temperatures of insulated built-up roofs.

  20. Role of Hot Water System Design on Factors Influential to Pathogen Regrowth: Temperature, Chlorine Residual, Hydrogen Evolution, and Sediment

    PubMed Central

    Brazeau, Randi H.; Edwards, Marc A.

    2013-01-01

    Abstract Residential water heating is linked to growth of pathogens in premise plumbing, which is the primary source of waterborne disease in the United States. Temperature and disinfectant residual are critical factors controlling increased concentration of pathogens, but understanding of how each factor varies in different water heater configurations is lacking. A direct comparative study of electric water heater systems was conducted to evaluate temporal variations in temperature and water quality parameters including dissolved oxygen levels, hydrogen evolution, total and soluble metal concentrations, and disinfectant decay. Recirculation tanks had much greater volumes of water at temperature ranges with potential for increased pathogen growth when set at 49°C compared with standard tank systems without recirculation. In contrast, when set at the higher end of acceptable ranges (i.e., 60°C), this relationship was reversed and recirculation systems had less volume of water at risk for pathogen growth compared with conventional systems. Recirculation tanks also tended to have much lower levels of disinfectant residual (standard systems had 40–600% higher residual), 4–6 times as much hydrogen, and 3–20 times more sediment compared with standard tanks without recirculation. On demand tankless systems had very small volumes of water at risk and relatively high levels of disinfectant residual. Recirculation systems may have distinct advantages in controlling pathogens via thermal disinfection if set at 60°C, but these systems have lower levels of disinfectant residual and greater volumes at risk if set at lower temperatures. PMID:24170969

  1. The analysis of anthropogenic factors in regional temperature change over East Asia

    NASA Astrophysics Data System (ADS)

    Guan, Xiaodan; Huang, Jianping; Guo, Ruixia

    2015-04-01

    In this study, the variability of surface air temperature (SAT) over different types of regions in East Asia are studied by using observation data from 1980-2012 under fast developing in economic. We found that the warming trends of the semi-arid regions are higher than other lands, which have increased 2.42°C as compared to the global annual mean temperature increase of 1.13°C over land. To investigate the causes of Enhanced Semi-Arid Warming (ESAW), we used an advanced dynamic-adjusted method proposed by Wallace et al. (2012) to analyse the adjusted temperature change. Our results point that the aerosol maybe takes the main role in adjusted temperature, especially in cold season. The anthropogenic-warming peak over semi-arid region plays the main role in the ESAW. Such anthropogenic-warming peak may be related to the long wave radiation change induced by aerosol in the air or the reduction of snow cover due to black carbon (BC) emission by fuels for winter residential heating. Besides the impact of aerosol over semi-arid region, the agricultural mulch creation, wind farms and other types of human activities may also make attribution to local SAT changes that need to be further studied.

  2. The measurement temperature: an important factor relating physicochemical and adhesive properties of yeast cells to biomaterials.

    PubMed

    Gallardo-Moreno, A M; Gonzlez-Martn, M L; Prez-Giraldo, C; Bruque, J M; Gmez-Garca, A C

    2004-03-15

    Flow chambers applied to the study of the initial adhesion process of Candida parapsilosis are rarely found in the literature. The ability of these microorganisms to proliferate and form biofilms in environments at temperatures around 22 or 37 degrees C is reflected in the contamination of laboratory instruments and material or in human implant infections, respectively. The initial interaction between yeasts and substrata is mediated by physicochemical forces, which in turn originate from the physicochemical surface properties of both interacting phases. In this context, this work aims to relate the initial rates of adhesion rates to glass and silicone of Candida parapsilosis, strains 294 and 289, grown at 22 and 37 degrees C with the theoretical predictions of the adhesion process, expressed by the interaction free energies and calculated through the physicochemical parameters, which are also measured at 22 and 37 degrees C. The results indicate that physicochemical parameters of yeasts are changed not only by the culture temperature but also by the measurement temperature; only when the measurement temperature is equal to the growth temperature a coherent relation between in vitro adhesion data and interaction free energies can be established. In this sense, the adhesion to glass is mediated by long-range forces or, what amounts to the same thing, by Lifshitz-van der Waals interaction free energy. On the other hand, the adhesion to silicone rubber seems to be moderated by acid-base interaction free energy, which involves the presence of short-range forces. Based on these results, it can be assumed that the substratum surface properties are directly related to the kind of force acting on the initial microbial adhesion process, while cell surface properties dictate the changes in the strength of the force between different samples. PMID:14972612

  3. Temperature, Relative Humidity and Pathogen Factors Influencing Phytophthora Infestans Development on Hairy Nightshade

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hairy nightshade (Solanum sarrachoides Sendt) is a common weed that can serve as an alternate host for potato late blight. Although environmental and pathogen factors are key variables affecting the development of late blight, little is known regarding their potential effects on infection of hairy n...

  4. Assessment of factors limiting Klamath River fall Chinook salmon production potential using historical flows and temperatures

    USGS Publications Warehouse

    Bartholow, John M.; Henriksen, James A.

    2006-01-01

    We parameterized and applied a deterministic salmon production model to infer the degree to which river flows and temperatures may limit freshwater production potential of the Klamath River in California. Specific parameter requirements, data sources, and significant assumptions are discussed in detail. Model simulations covered a wide variety of historical hydrologic and meteorologic conditions for 40+ years of environmental data. The model was calibrated only qualitatively, appearing to perform well in predicted outmigrant timing, but overestimating growth. Egg-to-outmigrant survival was near that reported for other rivers north of the Klamath River. Predicted production potential appeared to be determined by multiple causes involving both regularly occurring habitat-related constraints and irregularly occurring exposure to high water temperatures. Simulated production was greatest in years of intermediate water availability and was constrained in both dry and wet years, but for different reasons. Reducing mortality associated with limitations to juvenile habitat, if possible, would be expected to have the highest payoff in increasing production. Water temperature was important in determining predicted production in some years but overall was not predicted to be as important as physical microhabitat. No single mortality cause acted as a true a??bottlenecka?? on productiona?|

  5. Physiological Fluctuations in Brain Temperature as a Factor Affecting Electrochemical Evaluations of Extracellular Glutamate and Glucose in Behavioral Experiments

    PubMed Central

    2013-01-01

    The rate of any chemical reaction or process occurring in the brain depends on temperature. While it is commonly believed that brain temperature is a stable, tightly regulated homeostatic parameter, it fluctuates within 1–4 °C following exposure to salient arousing stimuli and neuroactive drugs, and during different behaviors. These temperature fluctuations should affect neural activity and neural functions, but the extent of this influence on neurochemical measurements in brain tissue of freely moving animals remains unclear. In this Review, we present the results of amperometric evaluations of extracellular glutamate and glucose in awake, behaving rats and discuss how naturally occurring fluctuations in brain temperature affect these measurements. While this temperature contribution appears to be insignificant for glucose because its extracellular concentrations are large, it is a serious factor for electrochemical evaluations of glutamate, which is present in brain tissue at much lower levels, showing smaller phasic fluctuations. We further discuss experimental strategies for controlling the nonspecific chemical and physical contributions to electrochemical currents detected by enzyme-based biosensors to provide greater selectivity and reliability of neurochemical measurements in behaving animals. PMID:23448428

  6. Accumulation of fatty acids in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoAcarboxylase, temperature, and co-immobilization with Azospirillum brasilense [corrected].

    PubMed

    Leyva, Luis A; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae. PMID:25129521

  7. Increase of Ozone Concentrations, Its Temperature Sensitivity and the Precursor Factor in South China

    NASA Technical Reports Server (NTRS)

    Lee, Y. C.; Shindell, D. T.; Faluvegi, G.; Wenig, M.; Lam, Y. F.; Ning, Z.; Hao, S.; Lai, C. S.

    2014-01-01

    Concerns have been raised about the possible connections between the local and regional photochemical problem and global warming. The current study assesses the trend of ozone in Hong Kong and the Pearl River Delta (PRD) in South China and investigates the interannual changes of sensitivity of ozone to air temperature, as well as the trends in regional precursors. Results reveal, at the three monitoring sites from the mid-1990s to 2010, an increase in the mean ozone concentrations from 1.0 to 1.6 microgram m(exp -3) per year. The increase occurred in all seasons, with the highest rate in autumn. This is consistent with trends and temperature anomalies in the region. The increase in the sensitivity of ozone to temperature is clearly evident from the correlation between ozone (OMI [Ozone Monitoring Instrument] column amount) and surface air temperature (from the Atmospheric Infrared Sounder) displayed in the correlation maps for the PRD during the prominently high ozone period of July September. It is observed to have increased from 2005 to 2010, the latter being the hottest year on record globally. To verify this temporal change in sensitivity, the ground-level trends of correlation coefficients/regression slopes are analysed. As expected, results reveal a statistically significant upward trend over a 14-year period (19972010). While the correlation revealed in the correlation maps is in agreement with the corresponding OMI ozone maps when juxtaposed, temperature sensitivity of surface ozone also shows an association with ozone concentration, with R0.5. These characteristics of ozone sensitivity are believed to have adverse implications for the region. As shown by ground measurements and/or satellite analyses, the decrease in nitrogen oxides (NO2) and NO(sub x) in Hong Kong is not statistically significant whileNO2 of thePRD has only very slightly changed. However, carbon dioxide has remarkably declined in the whole region. While these observations concerning precursors do not seem to adequately support an increasing ozone trend, measured surface levels of formaldehyde, a proxy for volatile organic compound (VOC) emissions, have risen significantly in the PRD (20042010). Hence, the reactive VOCs in the PRD are likely to be the main culprit for the increase of ozone, as far as precursors are concerned. Despite the prevailing problem, model simulations suggest prospects for improvement in the future.

  8. Curvature-correction-based time-domain CMOS smart temperature sensor with an inaccuracy of -0.8?C-1.2?C after one-point calibration from -40?C to 120?C.

    PubMed

    Chen, Chun-Chi; Lin, Shih-Hao; Lin, Yi

    2014-06-01

    This paper proposes a time-domain CMOS smart temperature sensor featuring on-chip curvature correction and one-point calibration support for thermal management systems. Time-domain inverter-based temperature sensors, which exhibit the advantages of low power and low cost, have been proposed for on-chip thermal monitoring. However, the curvature is large for the thermal transfer curve, which substantially affects the accuracy as the temperature range increases. Another problem is that the inverter is sensitive to process variations, resulting in difficulty for the sensors to achieve an acceptable accuracy for one-point calibration. To overcome these two problems, a temperature-dependent oscillator with curvature correction is proposed to increase the linearity of the oscillatory width, thereby resolving the drawback caused by a costly off-chip second-order master curve fitting. For one-point calibration support, an adjustable-gain time amplifier was adopted to eliminate the effect of process variations, with the assistance of a calibration circuit. The proposed circuit occupied a small area of 0.073 mm(2) and was fabricated in a TSMC CMOS 0.35-?m 2P4M digital process. The linearization of the oscillator and the effect cancellation of process variations enabled the sensor, which featured a fixed resolution of 0.049?C/LSB, to achieve an optimal inaccuracy of -0.8?C to 1.2?C after one-point calibration of 12 test chips from -40?C to 120?C. The power consumption was 35 ?W at a sample rate of 10 samples/s. PMID:24985845

  9. Curvature-correction-based time-domain CMOS smart temperature sensor with an inaccuracy of -0.8 C-1.2 C after one-point calibration from -40 C to 120 C

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Chi; Lin, Shih-Hao; Lin, Yi

    2014-06-01

    This paper proposes a time-domain CMOS smart temperature sensor featuring on-chip curvature correction and one-point calibration support for thermal management systems. Time-domain inverter-based temperature sensors, which exhibit the advantages of low power and low cost, have been proposed for on-chip thermal monitoring. However, the curvature is large for the thermal transfer curve, which substantially affects the accuracy as the temperature range increases. Another problem is that the inverter is sensitive to process variations, resulting in difficulty for the sensors to achieve an acceptable accuracy for one-point calibration. To overcome these two problems, a temperature-dependent oscillator with curvature correction is proposed to increase the linearity of the oscillatory width, thereby resolving the drawback caused by a costly off-chip second-order master curve fitting. For one-point calibration support, an adjustable-gain time amplifier was adopted to eliminate the effect of process variations, with the assistance of a calibration circuit. The proposed circuit occupied a small area of 0.073 mm2 and was fabricated in a TSMC CMOS 0.35-?m 2P4M digital process. The linearization of the oscillator and the effect cancellation of process variations enabled the sensor, which featured a fixed resolution of 0.049 C/LSB, to achieve an optimal inaccuracy of -0.8 C to 1.2 C after one-point calibration of 12 test chips from -40 C to 120 C. The power consumption was 35 ?W at a sample rate of 10 samples/s.

  10. The effects of incomplete annealing on the temperature dependence of sheet resistance and gage factor in aluminum and phosphorus implanted silicon on sapphire

    NASA Technical Reports Server (NTRS)

    Pisciotta, B. P.; Gross, C.

    1976-01-01

    Partial annealing of damage to the crystal lattice during ion implantation reduces the temperature coefficient of resistivity of ion-implanted silicon, while facilitating controlled doping. Reliance on this method for temperature compensation of the resistivity and strain-gage factor is discussed. Implantation conditions and annealing conditions are detailed. The gage factor and its temperature variation are not drastically affected by crystal damage for some crystal orientations. A model is proposed to account for the effects of electron damage on the temperature dependence of resistivity and on silicon piezoresistance. The results are applicable to the design of silicon-on-sapphire strain gages with high gage factors.

  11. The time of day differently influences fatigue and locomotor activity: is body temperature a key factor?

    PubMed

    Machado, Frederico Sander Mansur; Rodovalho, Gisele Vieira; Coimbra, Cndido Celso

    2015-03-01

    The aim of this study was to verify the possible interactions between exercise capacity and spontaneous locomotor activity (SLA) during the oscillation of core body temperature (Tb) that occurs during the light/dark cycle. Wistar rats (n=11) were kept at an animal facility under a light/dark cycle of 14/10h at an ambient temperature of 23C and water and food ad libitum. Initially, in order to characterize the daily oscillation in SLA and Tb of the rats, these parameters were continuously recorded for 24h using an implantable telemetric sensor (G2 E-Mitter). The animals were randomly assigned to two progressive exercise test protocols until fatigue during the beginning of light and dark-phases. Fatigue was defined as the moment rats could not keep pace with the treadmill. We assessed the time to fatigue, workload and Tb changes induced by exercise. Each test was separated by 3days. Our results showed that exercise capacity and heat storage were higher during the light-phase (p<0.05). In contrast, we observed that both SLA and Tb were higher during the dark-phase (p<0.01). Notably, the correlation analysis between the amount of SLA and the running capacity observed at each phase of the daily cycle revealed that, regardless of the time of the day, both types of locomotor physical activity have an important inherent component (r=0.864 and r=0.784, respectively, p<0.01) without a direct relationship between them. This finding provides further support for the existence of specific control mechanisms for each type of physical activity. In conclusion, our data indicate that the relationship between the body temperature and different types of physical activity might be affected by the light/dark cycle. These results mean that, although exercise performance and spontaneous locomotor activity are not directly associated, both are strongly influenced by daily cycles of light and dark. PMID:25479573

  12. Growth, condition factor, and bioenergetics modeling link warmer stream temperatures below a small dam to reduced performance of juvenile steelhead

    USGS Publications Warehouse

    Sauter, S.T.; Connolly, P.J.

    2010-01-01

    We investigated the growth and feeding performance of juvenile steelhead Oncorhynchus mykiss using field measures and bioenergetics modeling. Juvenile steelhead populations were sampled from mid-June through August 2004 at study sites upstream and downstream of Hemlock Dam. The growth and diet of juvenile steelhead were determined for a warm (summer) and subsequent (late summer) transitional period at each study site. Empirical data on the growth and diet of juvenile steelhead and mean daily temperatures were used in a bioenergetics model to estimate the proportion of maximum consumption achieved by juvenile steelhead by site and period. Modeled estimates of feeding performance were better for juvenile steelhead at the upstream compared to the downstream site during both periods. The median condition factor of juvenile steelhead did not change over the summer at the upstream site, but showed a significant decline over time at the downstream site. A negative trend in median condition factor at the downstream site supported bioenergetics modeling results that suggested the warmer stream temperatures had a negative impact on juvenile steelhead. Bioenergetics modeling predicted a lower feeding performance for juvenile steelhead rearing downstream compared to upstream of Hemlock Dam although food availability appeared to be limited at both study sites during the warm period. Warmer water temperatures, greater diel variation, and change in diel pattern likely led to the reduced feeding performance and reduced growth, which could have affected the overall survival of juvenile steelhead downstream of Hemlock Dam. ?? 2010 by the Northwest Scientific Association.

  13. Sample weight and digestion temperature as critical factors in mercury determination in fish

    SciTech Connect

    Sadiq, M.; Zaidi, T.H.; Al-Mohana, H. )

    1991-09-01

    The concern about mercury (Hg) pollution of the marine environment started with the well publicized case of Minimata (Japan) where in the 1950s several persons died or became seriously ill after consuming fish or shellfish containing high levels of methylmercury. It is now accepted that Hg contaminated seafoods constitute a hazard to human health. To safeguard humans, accurate determination of Hg in marine biota is, therefore, very important. Two steps are involved in the determination of total Hg in biological materials: (a) decomposition of organic matrix (sample preparation), and (b) determination of Hg in aliquot samples. Although the procedures for determining Hg using the cold vapor technique are well established, sample preparation procedures have not been standardized. In general, samples of marine biota have been prepared by digesting different weights at different temperatures, by using mixtures of different chemicals and of varying quantities, and by digesting for variable durations. The objectives of the present paper were to evaluate the effects of sample weights and digestion temperatures on Hg determination in fish.

  14. Human milk antibacterial factors: the effect of temperature on defense systems.

    PubMed

    Chen, H Y; Allen, J C

    2001-01-01

    Bovine milk will eventually spoil at refrigeration temperatures, but endogenous or exogenous pathogenic or spoilage bacteria in human milk stored for delayed feeding will die. We investigated the mechanism for these antibacterial properties and their response to high-tempertature, short-time (HTST, 72 degrees C-75 degrees C, 15 sec) and low-temperature long-time (LTLT, 65 degrees C, 30 min) pasteurization. Nonpathogenic Listeria innocua (10(6) cfu/mL) was inoculated into raw and processed bovine and human milk; bacterial plate counts twice weekly determined antibacterial activities. Up to 99% of L. innocua were killed and further growth was inhibited in raw and pasteurized human milk for at least 60 days at 4 degrees C. Reactive IgA antibodies against Listeria antigens were demonstrated by enzyme immunoassay in some human milk samples; sIgA activity against Escherichia coli O antigens was significantly decreased by heat treatments (raw, 1.8; HTST, 1.1; LTLT, 1.3 activity units). Adding human lactoferrin (0.5-20 mg/mL) to the Listeria inoculum (approximately 10(7) cfu/mL) in 1% peptone water did not inhibit bacterial growth. PMID:11787700

  15. Factors affecting sorption of nitro explosives to biochar: pyrolysis temperature, surface treatment, competition, and dissolved metals.

    PubMed

    Oh, Seok-Young; Seo, Yong-Deuk

    2015-05-01

    The application of rice straw-derived biochar for removing nitro explosives, including 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), from contaminated water was investigated through batch experiments. An increase in the pyrolysis temperature from 250 to 900C in general led to higher pH, surface area, cation exchange capacity (CEC), point of zero charge, and C:O ratio of biochar. The maximum sorption capacity estimated by a mixed sorption-partition model increased when pyrolysis temperatures were elevated from 250 to 900C, indicating that C content and aromaticity of biochar were strongly related to the sorption of nitro explosives to biochar. Surface treatment with acid or oxidant increased the sorption capacity of biochar for the two strong ?-acceptor compounds (DNT and TNT) but not for RDX. However, the enhancement of sorption capacity was not directly related to increased surface area and CEC. Compared with single-sorption systems, coexistence of explosives or cationic metals resulted in decreased sorption of each explosive to biochar, suggesting that sorption of nitro explosives and cationic metals to electron-rich portions in biochar was competitive. Our results suggest that ?-? electron donor acceptor interactions are main sorption mechanisms and that changing various conditions can enhance or reduce the sorption of nitro explosives to biochar. PMID:26024263

  16. Transcriptome-based discovery of AP2/ERF transcription factors related to temperature stress in tea plant (Camellia sinensis).

    PubMed

    Wu, Zhi-Jun; Li, Xing-Hui; Liu, Zhi-Wei; Li, Hui; Wang, Yong-Xin; Zhuang, Jing

    2015-11-01

    Tea plant (Camellia sinensis) is an important natural resource for the global supply of non-alcoholic beverage production. The extension of tea plant cultivation is challenged by biotic and abiotic stresses. Transcription factors (TFs) of the APETALA 2 (AP2)/ethylene-responsive factor (ERF) family are involved in growth and anti-stresses through multifaceted transcriptional regulation in plants. This study comprehensively analyzed AP2/ERF family TFs from C. sinensis on the basis of the transcriptome sequencing data of four tea plant cultivars, namely, 'Yunnanshilixiang', 'Chawansanhao', 'Ruchengmaoyecha', and 'Anjibaicha'. A total of 89 putative AP2/ERF transcription factors with full-length AP2 domain were identified from C. sinensis and classified into five subfamilies, namely, AP2, dehydration-responsive-element-binding (DREB), ERF, related to ABI3/VP (RAV), and Soloist. All identified CsAP2/ERF genes presented relatively stable expression levels in the four tea plant cultivars. Many groups also showed cultivar specificity. Five CsAP2/ERF genes from each AP2/ERF subfamily (DREB, ERF, AP2, and RAV) were related to temperature stresses; these results indicated that AP2/ERF TFs may play important roles in abnormal temperature stress response in C. sinensis. PMID:26233577

  17. Influence of various stabilizing factors on an elemental sulfur emulsion during high-temperature leaching of nickel-pyrrhotine concentrates

    NASA Astrophysics Data System (ADS)

    Naftal', M. N.; Naboichenko, S. S.; Salimzhanova, E. V.; Bol'shakova, O. V.; Saverskaya, T. P.

    2015-03-01

    It is shown that the problems of decomposition of the three-phase sulfur emulsions that form during hydrothermal oxidation of pyrrhotine and the choice of conditions of their stabilization represent one of the main problems of the theory and practice of the pressure oxidizing leaching (POL) of nickel-pyrrhotine concentrates (NPCs) carried out at high temperatures. The character and the degree of influence of a number of stabilizing factors (mixing intensity, consumption of commercial lignosulphonates (LSNs), amount of added gangue) on the particle size distribution of elemental sulfur during POL of NPCs, which have different contents of the main components, are studied. Mathematical statistics is used to derive regression equations and response surfaces to describe the dependence of the extraction of elemental sulfur into hard-to-float particle size classes (-10 µm, +150 µm) on the factors under study. It is found that the key factor that determines the particle size distribution of elemental sulfur is the consumption of LSN surfactants during high-temperature leaching of NPCs irrespective of the chemical-mineralogical composition. A pronounced synergetic effect of a positive influence of LSN and a rock-containing addition is experimentally detected during leaching of high-sulfur NPC.

  18. Radiosondes Corrected for Inaccuracy in RH Measurements

    DOE Data Explorer

    Miloshevich, Larry

    2008-01-15

    Corrections for inaccuracy in Vaisala radiosonde RH measurements have been applied to ARM SGP radiosonde soundings. The magnitude of the corrections can vary considerably between soundings. The radiosonde measurement accuracy, and therefore the correction magnitude, is a function of atmospheric conditions, mainly T, RH, and dRH/dt (humidity gradient). The corrections are also very sensitive to the RH sensor type, and there are 3 Vaisala sensor types represented in this dataset (RS80-H, RS90, and RS92). Depending on the sensor type and the radiosonde production date, one or more of the following three corrections were applied to the RH data: Temperature-Dependence correction (TD), Contamination-Dry Bias correction (C), Time Lag correction (TL). The estimated absolute accuracy of NIGHTTIME corrected and uncorrected Vaisala RH measurements, as determined by comparison to simultaneous reference-quality measurements from Holger Voemel's (CU/CIRES) cryogenic frostpoint hygrometer (CFH), is given by Miloshevich et al. (2006).

  19. The efficiency calibration and development of environmental correction factors for an in situ high-resolution gamma spectroscopy well logging system

    SciTech Connect

    Giles, J.R.

    1996-05-01

    A Gamma Spectroscopy Logging System (GSLS) has been developed to study sub-surface radionuclide contamination. Absolute efficiency calibration of the GSLS was performed using simple cylindrical borehole geometry. The calibration source incorporated naturally occurring radioactive material (NORM) that emitted photons ranging from 186-keV to 2,614-keV. More complex borehole geometries were modeled using commercially available shielding software. A linear relationship was found between increasing source thickness and relative photon fluence rates at the detector. Examination of varying porosity and moisture content showed that as porosity increases, relative photon fluence rates increase linearly for all energies. Attenuation effects due to iron, water, PVC, and concrete cylindrical shields were found to agree with previous studies. Regression analyses produced energy-dependent equations for efficiency corrections applicable to spectral gamma-ray well logs collected under non-standard borehole conditions.

  20. Single-crystal sapphire resonator at millikelvin temperatures: Observation of thermal bistability in high-Q factor whispering gallery modes

    SciTech Connect

    Creedon, Daniel L.; Tobar, Michael E.; Le Floch, Jean-Michel; Reshitnyk, Yarema; Duty, Timothy

    2010-09-01

    Resonance modes in single crystal sapphire ({alpha}-Al{sub 2}O{sub 3}) exhibit extremely high electrical and mechanical Q factors ({approx_equal}10{sup 9} at 4 K), which are important characteristics for electromechanical experiments at the quantum limit. We report the cool down of a bulk sapphire sample below superfluid liquid-helium temperature (1.6 K) to as low as 25 mK. The electromagnetic properties were characterized at microwave frequencies, and we report the observation of electromagnetically induced thermal bistability in whispering gallery modes due to the material T{sup 3} dependence on thermal conductivity and the ultralow dielectric loss tangent. We identify ''magic temperatures'' between 80 and 2100 mK, the lowest ever measured, at which the onset of bistability is suppressed and the frequency-temperature dependence is annulled. These phenomena at low temperatures make sapphire suitable for quantum metrology and ultrastable clock applications, including the possible realization of the quantum-limited sapphire clock.

  1. Genetically distinct populations of northern shrimp, Pandalus borealis, in the North Atlantic: adaptation to different temperatures as an isolation factor.

    PubMed

    Jorde, Per Erik; Svik, Guldborg; Westgaard, Jon-Ivar; Albretsen, Jon; Andr, Carl; Hvingel, Carsten; Johansen, Torild; Sandvik, Anne Dagrun; Kingsley, Michael; Jrstad, Knut Eirik

    2015-04-01

    The large-scale population genetic structure of northern shrimp, Pandalus borealis, was investigated over the species' range in the North Atlantic, identifying multiple genetically distinct groups. Genetic divergence among sample localities varied among 10 microsatellite loci (range: FST = -0.0002 to 0.0475) with a highly significant average (FST = 0.0149; P < 0.0001). In contrast, little or no genetic differences were observed among temporal replicates from the same localities (FST = 0.0004; P = 0.33). Spatial genetic patterns were compared to geographic distances, patterns of larval drift obtained through oceanographic modelling, and temperature differences, within a multiple linear regression framework. The best-fit model included all three factors and explained approximately 29% of all spatial genetic divergence. However, geographic distance and larval drift alone had only minor effects (2.5-4.7%) on large-scale genetic differentiation patterns, whereas bottom temperature differences explained most (26%). Larval drift was found to promote genetic homogeneity in parts of the study area with strong currents, but appeared ineffective across large temperature gradients. These findings highlight the breakdown of gene flow in a species with a long pelagic larval phase (up to 3 months) and indicate a role for local adaptation to temperature conditions in promoting evolutionary diversification and speciation in the marine environment. PMID:25782085

  2. [Temperature as a