Monte Carlo determination of the infinite matrix dose rate correction factors for 250 μm quartz and TLD500 chip

International Nuclear Information System (INIS)

Baly, L.; Martín, G.; Quesada, I.; Padilla, F.; Arteche, R.

2015-01-01

A new approach based on the Monte Carlo simulation is used to calculate the infinite matrix dose rate correction factors of gamma, beta and internal conversion radiations for 250 μm diameter grains of quartz and TLD500 chips. Here, the dependence of the correction factor on the radiation energy is initially calculated for each type of emitted particle and with this result the correction factors for the 232 Th and 238 U series and 40 K are determined. This analysis is made for dry soil and also for different levels of water content in it. The obtained beta correction factors for quartz are in good agreement with those previously reported. For the TLD500 chip certain differences with previously reported data are found. The analysis of the gamma water correction factor for quartz based on Zimmerman equation shows the correspondence with the similar correction factor for electrons. In the case of TLD500 chip a gamma water correction factor value of 1.0 was found. - Highlights: • A new approach based on Monte Carlo simulation is used to compute infinite matrix dose rate correction factors. • Infinite matrix models with real dimensions were analyzed within 3% uncertainties. • The dependence of grain size attenuation on particle energy is determined. • The same dependence for water correction factors is also analyzed

Time-dependent phase error correction using digital waveform synthesis

Science.gov (United States)

Doerry, Armin W.; Buskirk, Stephen

2017-10-10

The various technologies presented herein relate to correcting a time-dependent phase error generated as part of the formation of a radar waveform. A waveform can be pre-distorted to facilitate correction of an error induced into the waveform by a downstream operation/component in a radar system. For example, amplifier power droop effect can engender a time-dependent phase error in a waveform as part of a radar signal generating operation. The error can be quantified and an according complimentary distortion can be applied to the waveform to facilitate negation of the error during the subsequent processing of the waveform. A time domain correction can be applied by a phase error correction look up table incorporated into a waveform phase generator.

Megavoltage photon beam attenuation by carbon fiber couch tops and its prediction using correction factors

International Nuclear Information System (INIS)

Hayashi, Naoki; Shibamoto, Yuta; Obata, Yasunori; Kimura, Takashi; Nakazawa, Hisato; Hagiwara, Masahiro; Hashizume, Chisa I.; Mori, Yoshimasa; Kobayashi, Tatsuya

2010-01-01

The purpose of this study was to evaluate the effect of megavoltage photon beam attenuation (PBA) by couch tops and to propose a method for correction of PBA. Four series of phantom measurements were carried out. First, PBA by the exact couch top (ECT, Varian) and Imaging Couch Top (ICT, BrainLAB) was evaluated using a water-equivalent phantom. Second, PBA by Type-S system (Med-Tec), ECT and ICT was compared with a spherical phantom. Third, percentage depth dose (PDD) after passing through ICT was measured to compare with control data of PDD. Forth, the gantry angle dependency of PBA by ICT was evaluated. Then, an equation for PBA correction was elaborated and correction factors for PBA at isocenter were obtained. Finally, this method was applied to a patient with hepatoma. PBA of perpendicular beams by ICT was 4.7% on average. With the increase in field size, the measured values became higher. PBA by ICT was greater than that by Type-S system and ECT. PBA increased significantly as the angle of incidence increased, ranging from 4.3% at 180 deg to 11.2% at 120 deg. Calculated doses obtained by the equation and correction factors agreed quite well with the measured doses between 120 deg and 180 deg of angles of incidence. Also in the patient, PBA by ICT was corrected quite well by the equation and correction factors. In conclusion, PBA and its gantry angle dependency by ICT were observed. This simple method using the equation and correction factors appeared useful to correct the isocenter dose when the PBA effect cannot be corrected by a treatment planning system. (author)

Energy dependence corrections to MOSFET dosimetric sensitivity

International Nuclear Information System (INIS)

Cheung, T.; Yu, P.K.N.; Butson, M.J.; Illawarra Cancer Care Centre, Crown St, Wollongong

2009-01-01

Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to reading to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

Energy dependence corrections to MOSFET dosimetric sensitivity.

Science.gov (United States)

Cheung, T; Butson, M J; Yu, P K N

2009-03-01

Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6 MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to readings to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

Correction factors for 13C-labelled substrate oxidation at whole-body and muscle level

DEFF Research Database (Denmark)

Van Hall, Gerrit

1999-01-01

acid cycle. Changes in metabolic rate induced, for example, by feeding, hormonal changes and physical activity, as well as infusion time, have been shown to affect both correction factors. The present paper explains the theoretical and physiological basis of these correction factors and makes...... for the proportion of labelled CO2 that is produced via oxidation but not excreted. Furthermore, depending on the substrate and position of the C label(s), there may also be a need to correct for labelled C from the metabolized substrate that does not appear as CO2, but rather becomes temporarily fixed in other...

Calculation of the Pitot tube correction factor for Newtonian and non-Newtonian fluids.

Science.gov (United States)

Etemad, S Gh; Thibault, J; Hashemabadi, S H

2003-10-01

This paper presents the numerical investigation performed to calculate the correction factor for Pitot tubes. The purely viscous non-Newtonian fluids with the power-law model constitutive equation were considered. It was shown that the power-law index, the Reynolds number, and the distance between the impact and static tubes have a major influence on the Pitot tube correction factor. The problem was solved for a wide range of these parameters. It was shown that employing Bernoulli's equation could lead to large errors, which depend on the magnitude of the kinetic energy and energy friction loss terms. A neural network model was used to correlate the correction factor of a Pitot tube as a function of these three parameters. This correlation is valid for most Newtonian, pseudoplastic, and dilatant fluids at low Reynolds number.

Syringe calibration factors and volume correction factors for the NPL secondary standard radionuclide calibrator

CERN Document Server

Tyler, D K

2002-01-01

The activity assay of a radiopharmaceutical administration to a patient is normally achieved via the use of a radionuclide calibrator. Because of the different geometries and elemental compositions between plastic syringes and glass vials, the calibration factors for syringes may well be significantly different from those for the glass containers. The magnitude of these differences depends on the energies of the emitted photons. For some radionuclides variations have been observed of 70 %, it is therefore important to recalibrate for syringes or use syringe calibration factors. Calibration factors and volume correction factors have been derived for the NPL secondary standard radionuclide calibrator, for a variety of commonly used syringes and needles, for the most commonly used medical radionuclide.

Correction of SiPM temperature dependencies

International Nuclear Information System (INIS)

Kaplan, A.

2009-01-01

The performance of a high granular analogue hadronic calorimeter (AHCAL) using scintillator tiles with built-in Silicon Photomultiplier (SiPM) readout is reported. A muon beam is used for the minimum ionizing particle (MIP) based calibration of the single cells. The calibration chain including corrections for the non-linearity of the SiPM is presented. The voltage and temperature dependencies of the SiPM signal have been investigated using the versatile LED system of the AHCAL. Monitoring and correction methods are discussed. Measurements from the operation 2006 and 2007 at the CERN SPS test beam and data provided by the Institute for Theoretical and Experimental Physics (ITEP) in Moscow are compared.

Source distribution dependent scatter correction for PVI

International Nuclear Information System (INIS)

Barney, J.S.; Harrop, R.; Dykstra, C.J.

1993-01-01

Source distribution dependent scatter correction methods which incorporate different amounts of information about the source position and material distribution have been developed and tested. The techniques use image to projection integral transformation incorporating varying degrees of information on the distribution of scattering material, or convolution subtraction methods, with some information about the scattering material included in one of the convolution methods. To test the techniques, the authors apply them to data generated by Monte Carlo simulations which use geometric shapes or a voxelized density map to model the scattering material. Source position and material distribution have been found to have some effect on scatter correction. An image to projection method which incorporates a density map produces accurate scatter correction but is computationally expensive. Simpler methods, both image to projection and convolution, can also provide effective scatter correction

Monte Carlo study of MOSFET dosimeter dose correction factors considering energy spectrum of radiation field in a steam generator channel head

Energy Technology Data Exchange (ETDEWEB)

Cho, Sung Koo; Choi, Sang Hyoun; Kim, Chan Hyeong [Hanyang Univ., Seoul (Korea, Republic of)

2006-12-15

In Korea, a real-time effective dose measurement system is in development. The system uses 32 high-sensitivity MOSFET dosimeters to measure radiation doses at various organ locations in an anthropomorphic physical phantom. The MOSFET dosimeters are, however, mainly made of silicon and shows some degree of energy and angular dependence especially for low energy photons. This study determines the correction factors to correct for these dependences of the MOSFET dosimeters for accurate measurement of radiation doses at organ locations in the phantom. For this, first, the dose correction factors of MOSFET dosimeters were determined for the energy spectrum in the steam generator channel of the Kori Nuclear Power Plant Unit no.1 by Monte Carlo simulations. Then, the results were compared with the dose correction factors from 0.662 MeV and 1.25 MeV mono-energetic photons. The difference of the dose correction factors were found very negligible ({<=}1.5%), which in general shows that the dose corrections factors determined from 0.662 MeV and 1.25 MeV can be in a steam general channel head of a nuclear power plant. The measured effective dose was generally found to decrease by {approx}7% when we apply the dose correction factors.

49 CFR 325.73 - Microphone distance correction factors. 1

Science.gov (United States)

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Microphone distance correction factors. 1 325.73 Section 325.73 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR... MOTOR CARRIER NOISE EMISSION STANDARDS Correction Factors § 325.73 Microphone distance correction...

Correction factor for the experimental prompt neutron decay constant

International Nuclear Information System (INIS)

Talamo, Alberto; Gohar, Y.; Sadovich, S.; Kiyavitskaya, H.; Bournos, V.; Fokov, Y.; Routkovskaya, C.

2013-01-01

Highlights: • Definition of a spatial correction factor for the experimental prompt neutron decay constant. • Introduction of a MCNP6 calculation methodology to simulate Rossi-alpha distribution for pulsed neutron sources. • Comparison of MCNP6 results with experimental data for count rate, Rossi-alpha, and Feynman-alpha distributions. • Improvement of the comparison between numerical and experimental results by taking into account the dead-time effect. - Abstract: This study introduces a new correction factor to obtain the experimental effective multiplication factor of subcritical assemblies by the point kinetics formulation. The correction factor is defined as the ratio between the MCNP6 prompt neutron decay constant obtained in criticality mode and the one obtained in source mode. The correction factor mainly takes into account the longer neutron lifetime in the reflector region and the effects of the external neutron source. For the YALINA Thermal facility, the comparison between the experimental and computational effective multiplication factors noticeably improves after the application of the correction factor. The accuracy of the MCNP6 computational model of the YALINA Thermal subcritical assembly has been verified by reproducing the neutron count rate, Rossi-α, and Feynman-α distributions obtained from the experimental data

Resistivity Correction Factor for the Four-Probe Method: Experiment II

Science.gov (United States)

Yamashita, Masato; Yamaguchi, Shoji; Nishii, Toshifumi; Kurihara, Hiroshi; Enjoji, Hideo

1989-05-01

Experimental verification of the theoretically derived resistivity correction factor F is presented. Factor F can be applied to a system consisting of a disk sample and a four-probe array. Measurements are made on isotropic graphite disks and crystalline ITO films. Factor F can correct the apparent variations of the data and lead to reasonable resistivities and sheet resistances. Here factor F is compared to other correction factors; i.e. FASTM and FJIS.

Determination of non-uniformity correction factors for cylindrical ionization chambers close to 192Ir brachytherapy sources

International Nuclear Information System (INIS)

Toelli, H.; Bielajew, A. F.; Mattsson, O.; Sernbo, G.

1995-01-01

When ionization chambers are used in brachytherapy dosimetry, the measurements must be corrected for the non-uniformity of the incident photon fluence. The theory for determination of non-uniformity correction factors, developed by Kondo and Randolph (Rad. Res. 1960) assumes that the electron fluence within the air cavity is isotropic and does not take into account material differences in the chamber wall. The theory was extended by Bielajew (PMB 1990) using an anisotropic electron angular fluence in the cavity. In contrast to the theory by Kondo and Randolph, the anisotropic theory predicts a wall material dependence in the non-uniformity correction factors. This work presents experimental determination of non-uniformity correction factors at distances between 10 and 140 mm from an Ir-192 source. The experimental work makes use of a PTW23331-chamber and Farmer-type chambers (NE2571 and NE2581) with different materials in the walls. The results of the experiments agree well with the anisotropic theory. Due to the geometrical shape of the NE-type chambers, it is shown that the full length of the these chambers, 24.1mm, is not an appropriate input parameter when theoretical non-uniformity correction factors are evaluated

Bias-corrected estimation of stable tail dependence function

DEFF Research Database (Denmark)

Beirlant, Jan; Escobar-Bach, Mikael; Goegebeur, Yuri

2016-01-01

We consider the estimation of the stable tail dependence function. We propose a bias-corrected estimator and we establish its asymptotic behaviour under suitable assumptions. The finite sample performance of the proposed estimator is evaluated by means of an extensive simulation study where...

QED radiative corrections to impact factors

International Nuclear Information System (INIS)

Kuraev, E.A.; Lipatov, L.N.; Shishkina, T.V.

2001-01-01

We consider radiative corrections to the electron and photon impact factors. The generalized eikonal representation for the e + e - scattering amplitude at high energies and fixed momentum transfers is violated by nonplanar diagrams. An additional contribution to the two-loop approximation appears from the Bethe-Heitler mechanism of fermion pair production with the identity of the fermions in the final state taken into account. The violation of the generalized eikonal representation is also related to the charge parity conservation in QED. A one-loop correction to the photon impact factor for small virtualities of the exchanged photon is obtained using the known results for the cross section of the e + e - production during photon-nuclei interactions

Calculation of the flux attenuation and multiple scattering correction factors in time of flight technique for double differential cross section measurements

International Nuclear Information System (INIS)

Martin, G.; Coca, M.; Capote, R.

1996-01-01

Using Monte Carlo method technique , a computer code which simulates the time of flight experiment to measure double differential cross section was developed. The correction factor for flux attenuation and multiple scattering, that make a deformation to the measured spectrum, were calculated. The energy dependence of the correction factor was determined and a comparison with other works is shown. Calculations for Fe 56 at two different scattering angles were made. We also reproduce the experiment performed at the Nuclear Analysis Laboratory for C 12 at 25 celsius degree and the calculated correction factor for the is measured is shown. We found a linear relation between the scatter size and the correction factor for flux attenuation

Monte Carlo and experimental determination of correction factors for gamma knife perfexion small field dosimetry measurements

Science.gov (United States)

Zoros, E.; Moutsatsos, A.; Pappas, E. P.; Georgiou, E.; Kollias, G.; Karaiskos, P.; Pantelis, E.

2017-09-01

Detector-, field size- and machine-specific correction factors are required for precise dosimetry measurements in small and non-standard photon fields. In this work, Monte Carlo (MC) simulation techniques were used to calculate the k{{Qmsr},{{Q}0}}{{fmsr},{{f}ref}} and k{{Qclin},{{Q}msr}}{{fclin},{{f}msr}} correction factors for a series of ionization chambers, a synthetic microDiamond and diode dosimeters, used for reference and/or output factor (OF) measurements in the Gamma Knife Perfexion photon fields. Calculations were performed for the solid water (SW) and ABS plastic phantoms, as well as for a water phantom of the same geometry. MC calculations for the k{{Qclin},{{Q}msr}}{{fclin},{{f}msr}} correction factors in SW were compared against corresponding experimental results for a subset of ionization chambers and diode detectors. Reference experimental OF data were obtained through the weighted average of corresponding measurements using TLDs, EBT-2 films and alanine pellets. k{{Qmsr},{{Q}0}}{{fmsr},{{f}ref}} values close to unity (within 1%) were calculated for most of ionization chambers in water. Greater corrections of up to 6.0% were observed for chambers with relatively large air-cavity dimensions and steel central electrode. A phantom correction of 1.006 and 1.024 (breaking down to 1.014 from the ABS sphere and 1.010 from the accompanying ABS phantom adapter) were calculated for the SW and ABS phantoms, respectively, adding up to k{{Qmsr},{{Q}0}}{{fmsr},{{f}ref}} corrections in water. Both measurements and MC calculations for the diode and microDiamond detectors resulted in lower than unit k{{Qclin},{{Q}msr}}{{fclin},{{f}msr}} correction factors, due to their denser sensitive volume and encapsulation materials. In comparison, higher than unit k{{Qclin},{{Q}msr}}{{fclin},{{f}msr}} results for the ionization chambers suggested field size depended dose underestimations (being significant for the 4 mm field), with magnitude depending on the combination of

Determination of epithermal flux correction factor (α) for irradiation ...

African Journals Online (AJOL)

Due to resonance that occur in the epithermal energy region of a reactor, the flux spectra in that region deviates strongly from the ideal I/E law to a I/E1+α with alpha as the correction factor. The factor has to be determined if zirconium as monitor pairs to determine the correction factor for inner irradiation channel 5 and outer ...

Absorption correction factor in X-ray fluorescent quantitative analysis

International Nuclear Information System (INIS)

Pimjun, S.

1994-01-01

An experiment on absorption correction factor in X-ray fluorescent quantitative analysis were carried out. Standard samples were prepared from the mixture of Fe 2 O 3 and tapioca flour at various concentration of Fe 2 O 3 ranging from 5% to 25%. Unknown samples were kaolin containing 3.5% to-50% of Fe 2 O 3 Kaolin samples were diluted with tapioca flour in order to reduce the absorption of FeK α and make them easy to prepare. Pressed samples with 0.150 /cm 2 and 2.76 cm in diameter, were used in the experiment. Absorption correction factor is related to total mass absorption coefficient (χ) which varied with sample composition. In known sample, χ can be calculated by conveniently the formula. However in unknown sample, χ can be determined by Emission-Transmission method. It was found that the relationship between corrected FeK α intensity and contents of Fe 2 O 3 in these samples was linear. This result indicate that this correction factor can be used to adjust the accuracy of X-ray intensity. Therefore, this correction factor is essential in quantitative analysis of elements comprising in any sample by X-ray fluorescent technique

Exercise identity as a risk factor for exercise dependence.

Science.gov (United States)

Murray, Aja L; McKenzie, Karen; Newman, Emily; Brown, Erin

2013-05-01

The aim of the study was to explore the relationship between exercise identity and exercise dependence. We hypothesized that stronger exercise identities would be associated with greater odds of experiencing exercise dependence symptoms. Logistic regression was used to assess the extent of association between exercise identity and the risk of experiencing exercise dependence symptoms. Participants (101) were recruited online via sports clubs and social networking sites and were asked to complete online measures of exercise identity and exercise dependence. The overall model fit was a significant improvement on the baseline model, but only the exercise beliefs factor was significantly associated with the odds of dependence symptoms, with higher scores on the belief scale predicting greater odds of experiencing dependence symptoms. Exercise role identity, in contrast, was not significantly associated with odds of experiencing dependence symptoms. Per cent correct classification was 55.9% for asymptomatic and 88.2% for symptomatic individuals and the overall per cent correct classification was 77.5%. The relation between identity and dependence could represent both a fruitful research avenue and a potential therapeutic target for those experiencing dependence symptoms; although our findings only showed a relationship between one of the two factors of the exercise identity measure and dependence. Longitudinal research is required to examine the relationship between identity and dependence in the context of other variables to better understand why some individuals become exercise dependent whereas others do not. What is already known on this subject? Exercise identity has been identified as an important determinant of exercise behaviour and studies within the exercise identity framework have proven elucidative with respect to the psychological processes that may underpin commitment to exercise. It has separately been established that some individuals may become

Correction factor for hair analysis by PIXE

International Nuclear Information System (INIS)

Montenegro, E.C.; Baptista, G.B.; Castro Faria, L.V. de; Paschoa, A.S.

1980-01-01

The application of the Particle Induced X-ray Emission (PIXE) technique to analyse quantitatively the elemental composition of hair specimens brings about some difficulties in the interpretation of the data. The present paper proposes a correction factor to account for the effects of the energy loss of the incident particle with penetration depth, and X-ray self-absorption when a particular geometrical distribution of elements in hair is assumed for calculational purposes. The correction factor has been applied to the analysis of hair contents Zn, Cu and Ca as a function of the energy of the incident particle. (orig.)

Correction factor for hair analysis by PIXE

International Nuclear Information System (INIS)

Montenegro, E.C.; Baptista, G.B.; Castro Faria, L.V. de; Paschoa, A.S.

1979-06-01

The application of the Particle Induced X-ray Emission (PIXE) technique to analyse quantitatively the elemental composition of hair specimens brings about some difficulties in the interpretation of the data. The present paper proposes a correction factor to account for the effects of energy loss of the incident particle with penetration depth, and x-ray self-absorption when a particular geometrical distribution of elements in hair is assumed for calculational purposes. The correction factor has been applied to the analysis of hair contents Zn, Cu and Ca as a function of the energy of the incident particle.(Author) [pt

Correction factors for the NMi free-air ionization chamber for medium-energy x-rays calculated with the Monte Carlo method

International Nuclear Information System (INIS)

Grimbergen, T.W.M.; Dijk, E. van; Vries, W. de

1998-01-01

A new method is described for the determination of x-ray quality dependent correction factors for free-air ionization chambers. The method is based on weighting correction factors for mono-energetic photons, which are calculated using the Monte Carlo method, with measured air kerma spectra. With this method, correction factors for electron loss, scatter inside the chamber and transmission through the diaphragm and front wall have been calculated for the NMi free-air chamber for medium-energy x-rays for a wide range of x-ray qualities in use at NMi. The newly obtained correction factors were compared with the values in use at present, which are based on interpolation of experimental data for a specific set of x-ray qualities. For x-ray qualities which are similar to this specific set, the agreement between the correction factors determined with the new method and those based on the experimental data is better than 0.1%, except for heavily filtered x-rays generated at 250 kV. For x-ray qualities dissimilar to the specific set, differences up to 0.4% exist, which can be explained by uncertainties in the interpolation procedure of the experimental data. Since the new method does not depend on experimental data for a specific set of x-ray qualities, the new method allows for a more flexible use of the free-air chamber as a primary standard for air kerma for any x-ray quality in the medium-energy x-ray range. (author)

77 FR 22565 - Advisory Council on Dependents' Education; Open Meeting Notice; Correction

Science.gov (United States)

2012-04-16

... DEPARTMENT OF DEFENSE Office of the Secretary Advisory Council on Dependents' Education; Open Meeting Notice; Correction AGENCY: Department of Defense Education Activity (DoDEA), DoD. ACTION: Open meeting notice; correction. SUMMARY: On February 28, 2012 (77 FR 12039), the Advisory Council on...

Economic benefits of power factor correction at a nuclear facility

International Nuclear Information System (INIS)

Boger, R.M.; Dalos, W.; Juguilon, M.E.

1986-01-01

The economic benefits of correcting poor power factor at an operating nuclear facility are shown. A project approach for achieving rapid return of investment without disrupting plant availability is described. Examples of technical problems associated with using capacitors for power factor correction are presented

Spectral correction factors for conventional neutron dosemeters used in high-energy neutron environments

International Nuclear Information System (INIS)

Lee, K.W.; Sheu, R.J.

2015-01-01

High-energy neutrons (>10 MeV) contribute substantially to the dose fraction but result in only a small or negligible response in most conventional moderated-type neutron detectors. Neutron dosemeters used for radiation protection purpose are commonly calibrated with 252 Cf neutron sources and are used in various workplace. A workplace-specific correction factor is suggested. In this study, the effect of the neutron spectrum on the accuracy of dose measurements was investigated. A set of neutron spectra representing various neutron environments was selected to study the dose responses of a series of Bonner spheres, including standard and extended-range spheres. By comparing 252 Cf-calibrated dose responses with reference values based on fluence-to-dose conversion coefficients, this paper presents recommendations for neutron field characterisation and appropriate correction factors for responses of conventional neutron dosemeters used in environments with high-energy neutrons. The correction depends on the estimated percentage of high-energy neutrons in the spectrum or the ratio between the measured responses of two Bonner spheres (the 4P6-8 extended-range sphere versus the 6'' standard sphere). (authors)

Effects of Velocity-Dependent Force on the Magnetic Form Factors of Odd-Z Nuclei

International Nuclear Information System (INIS)

Tie-Kuang, Dong; Zhong-Zhou, Ren

2008-01-01

We investigate the effects of the velocity-dependent force on the magnetic form factors and magnetic moments of odd-Z nuclei. The form factors are calculated with the harmonic-oscillator wavefunctions. It is found that the contributions of the velocity-dependent force manifest themselves in the very large momentum transfer region (q ≥ 4fm- 1 ). In the low and medium q region the contributions of the velocity-dependent force are very small compared with those without this force. However, in the high-q region the contributions of the velocity-dependent force are larger than the normal form factors. The diffraction structures beyond the existing experimental data are found after the contributions of the velocity-dependent force are included. The formula of the correction to the single particle magnetic moment due to the velocity-dependent force is reproduced exactly in the long-wavelength limit (q = 0) of the M1 form factor

Volume correction factor in time dose relationships in brachytherapy

International Nuclear Information System (INIS)

Supe, S.J.; Sasane, J.B.

1987-01-01

Paterson's clinical data about the maximum tolerance doses for various volumes of interstitial implants with Ra-226 delivered in seven days was made use of in deriving volume correction factors for TDF and CRE concepts respectively for brachytherapy. The derived volume correction factors for TDF and for CRE differ fromthe one assumed for CRE by Kirk et al. and implied for TDF by Goitein. A normalising volume of 70 cc has been suggested for both CRE and TDF concepts for brachytherapy. A table showing the volume corrected TDF is presented for various volumes and dose rates for continuous irradiation. The use of this table is illustrated with examples. (orig.) [de

Derivation of Batho's correction factor for heterogeneities

International Nuclear Information System (INIS)

Lulu, B.A.; Bjaerngard, B.E.

1982-01-01

Batho's correction factor for dose in a heterogeneous, layered medium is derived from the tissue--air ratio method (TARM). The reason why the Batho factor is superior to the TARM factor at low energy is ascribed to the fact that it accounts for the distribution of the scatter-generating matter along the centerline. The poor behavior of the Batho factor at high energies is explained as a consequence of the lack of electron equilibrium at appreciable depth below the surface. Key words: Batho factor, heterogeneity, inhomogeneity, tissue--air ratio method

Corrections to the bag factor in B- anti B-mixing

Energy Technology Data Exchange (ETDEWEB)

Grozin, Andrey G. [BINP, Novosibirsk (Russian Federation); Klein, Rebecca; Mannel, Thomas; Pivovarov, Alexei A. [Universitaet Siegen (Germany)

2016-07-01

B- anti B-Mixing is parameterized by the matrix elements of local operators O{sub i}. For the computation of these matrix elements a bag factor B{sub i} can be introduced left angle anti B vertical stroke O{sub i} vertical stroke B right angle =B{sub i} left angle anti B vertical stroke O{sub i} vertical stroke B right angle {sup fac}, which is unity in naive factorization. Any deviation from unity describes the accuracy of the naive factorization prescription. Corrections to B{sub i} emerge from QCD radiative corrections and from nonperturbative contributions at order 1/m{sub b}. We present the current status of these corrections to B{sub i}.

Evaluation of off-axis wedge correction factor using diode dosimeters for estimation of delivered dose in external radiotherapy

International Nuclear Information System (INIS)

Allahverdi, Mahmoud; Shirazi, Alireza; Geraily, Ghazale; Mohammadkarim, Alireza; Esfehani, Mahbod; Nedaie, Hasanali

2012-01-01

An in vivo dosimetry system, using p-type diode dosimeters, was characterized for clinical applications of treatment machines ranging in megavoltage energies. This paper investigates two different models of diodes for externally wedged beams and explains a new algorithm for the calculation of the target dose at various tissue depths in external radiotherapy. The values of off-axis wedge correction factors were determined at two different positions in the wedged (toward the thick and thin edges) and in the non-wedged directions on entrance and exit surfaces of a polystyrene phantom in 60 Co and 6 MV photon beams. Depth transmission was defined on the entrance and exit surfaces to obtain the off-axis wedge correction factor at any depth. As the sensitivity of the diodes depends on physical characteristics (field size, source-skin distance (SSD), thickness, backscatter), correction factors were applied to the diode reading when measuring conditions different from calibration situations. The results indicate that needful correction factors for 60 Co wedged photons are usually larger than those for 6 MV wedged photon beams. In vivo dosimetry performed with the proposed algorithms at externally wedged beams has negligible probable errors (less than 0.5%) and is a reliable method for patient dose control. (author)

Evaluation of off-axis wedge correction factor using diode dosimeters for estimation of delivered dose in external radiotherapy

Directory of Open Access Journals (Sweden)

Mahmoud Allahverdi

2012-01-01

Full Text Available An in vivo dosimetry system, using p-type diode dosimeters, was characterized for clinical applications of treatment machines ranging in megavoltage energies. This paper investigates two different models of diodes for externally wedged beams and explains a new algorithm for the calculation of the target dose at various tissue depths in external radiotherapy. The values of off-axis wedge correction factors were determined at two different positions in the wedged (toward the thick and thin edges and in the non-wedged directions on entrance and exit surfaces of a polystyrene phantom in 60 Co and 6 MV photon beams. Depth transmission was defined on the entrance and exit surfaces to obtain the off-axis wedge correction factor at any depth. As the sensitivity of the diodes depends on physical characteristics [field size, source-skin distance (SSD, thickness, backscatter], correction factors were applied to the diode reading when measuring conditions different from calibration situations . The results indicate that needful correction factors for 60 Co wedged photons are usually larger than those for 6 MV wedged photon beams. In vivo dosimetry performed with the proposed algorithms at externally wedged beams has negligible probable errors (less than 0.5% and is a reliable method for patient dose control.

The determination of beam quality correction factors: Monte Carlo simulations and measurements.

Science.gov (United States)

González-Castaño, D M; Hartmann, G H; Sánchez-Doblado, F; Gómez, F; Kapsch, R-P; Pena, J; Capote, R

2009-08-07

Modern dosimetry protocols are based on the use of ionization chambers provided with a calibration factor in terms of absorbed dose to water. The basic formula to determine the absorbed dose at a user's beam contains the well-known beam quality correction factor that is required whenever the quality of radiation used at calibration differs from that of the user's radiation. The dosimetry protocols describe the whole ionization chamber calibration procedure and include tabulated beam quality correction factors which refer to 60Co gamma radiation used as calibration quality. They have been calculated for a series of ionization chambers and radiation qualities based on formulae, which are also described in the protocols. In the case of high-energy photon beams, the relative standard uncertainty of the beam quality correction factor is estimated to amount to 1%. In the present work, two alternative methods to determine beam quality correction factors are prescribed-Monte Carlo simulation using the EGSnrc system and an experimental method based on a comparison with a reference chamber. Both Monte Carlo calculations and ratio measurements were carried out for nine chambers at several radiation beams. Four chamber types are not included in the current dosimetry protocols. Beam quality corrections for the reference chamber at two beam qualities were also measured using a calorimeter at a PTB Primary Standards Dosimetry Laboratory. Good agreement between the Monte Carlo calculated (1% uncertainty) and measured (0.5% uncertainty) beam quality correction factors was obtained. Based on these results we propose that beam quality correction factors can be generated both by measurements and by the Monte Carlo simulations with an uncertainty at least comparable to that given in current dosimetry protocols.

Scattering amplitudes and static atomic correction factors for the composition-sensitive 002 reflection in sphalerite ternary III-V and II-VI semiconductors.

Science.gov (United States)

Schowalter, M; Müller, K; Rosenauer, A

2012-01-01

Modified atomic scattering amplitudes (MASAs), taking into account the redistribution of charge due to bonds, and the respective correction factors considering the effect of static atomic displacements were computed for the chemically sensitive 002 reflection for ternary III-V and II-VI semiconductors. MASAs were derived from computations within the density functional theory formalism. Binary eight-atom unit cells were strained according to each strain state s (thin, intermediate, thick and fully relaxed electron microscopic specimen) and each concentration (x = 0, …, 1 in 0.01 steps), where the lattice parameters for composition x in strain state s were calculated using continuum elasticity theory. The concentration dependence was derived by computing MASAs for each of these binary cells. Correction factors for static atomic displacements were computed from relaxed atom positions by generating 50 × 50 × 50 supercells using the lattice parameter of the eight-atom unit cells. Atoms were randomly distributed according to the required composition. Polynomials were fitted to the composition dependence of the MASAs and the correction factors for the different strain states. Fit parameters are given in the paper.

Personality Assessment Inventory scale characteristics and factor structure in the assessment of alcohol dependency.

Science.gov (United States)

Schinka, J A

1995-02-01

Individual scale characteristics and the inventory structure of the Personality Assessment Inventory (PAI; Morey, 1991) were examined by conducting internal consistency and factor analyses of item and scale score data from a large group (N = 301) of alcohol-dependent patients. Alpha coefficients, mean inter-item correlations, and corrected item-total scale correlations for the sample paralleled values reported by Morey for a large clinical sample. Minor differences in the scale factor structure of the inventory from Morey's clinical sample were found. Overall, the findings support the use of the PAI in the assessment of personality and psychopathology of alcohol-dependent patients.

Perturbative corrections to B → D form factors in QCD

Science.gov (United States)

Wang, Yu-Ming; Wei, Yan-Bing; Shen, Yue-Long; Lü, Cai-Dian

2017-06-01

We compute perturbative QCD corrections to B → D form factors at leading power in Λ/ m b , at large hadronic recoil, from the light-cone sum rules (LCSR) with B-meson distribution amplitudes in HQET. QCD factorization for the vacuum-to- B-meson correlation function with an interpolating current for the D-meson is demonstrated explicitly at one loop with the power counting scheme {m}_c˜ O(√{Λ {m}_b}) . The jet functions encoding information of the hard-collinear dynamics in the above-mentioned correlation function are complicated by the appearance of an additional hard-collinear scale m c , compared to the counterparts entering the factorization formula of the vacuum-to- B-meson correction function for the construction of B → π from factors. Inspecting the next-to-leading-logarithmic sum rules for the form factors of B → Dℓν indicates that perturbative corrections to the hard-collinear functions are more profound than that for the hard functions, with the default theory inputs, in the physical kinematic region. We further compute the subleading power correction induced by the three-particle quark-gluon distribution amplitudes of the B-meson at tree level employing the background gluon field approach. The LCSR predictions for the semileptonic B → Dℓν form factors are then extrapolated to the entire kinematic region with the z-series parametrization. Phenomenological implications of our determinations for the form factors f BD +,0 ( q 2) are explored by investigating the (differential) branching fractions and the R( D) ratio of B → Dℓν and by determining the CKM matrix element |V cb | from the total decay rate of B → Dμν μ .

Influence factors and corrections of low-energy γ-ray penetration in ash analysis

International Nuclear Information System (INIS)

Cheng Bo; Tuo Xianguo; Zhou Jianbin; Tong Yunfu

2002-01-01

The author introduces the system of the coal ash analyzer. This system is based on the low-energy γ-ray source 241 Am emitted two kinds of energy peaks 26.4 keV and 59.6 keV to analyze the ash in coal with the penetration way. The author also offers the factors to influence the accuracy of ash analysis, such as the size of coal, the environmental temperature, the important elements in coal, and water in coal too. At the same time, depending on the cause of the factors, it offer some methods of correction such as the way of the auto-hold energy peak, the way of the auto-compensation way, and so on. The author also mentions the other influence factors of the measurement accuracy to be noticed during the experiment. All these aim at clearing off the influence factors of measurement accuracy through the experiments

Theoretical determination of gamma spectrometry systems efficiency based on probability functions. Application to self-attenuation correction factors

Energy Technology Data Exchange (ETDEWEB)

Barrera, Manuel, E-mail: manuel.barrera@uca.es [Escuela Superior de Ingeniería, University of Cadiz, Avda, Universidad de Cadiz 10, 11519 Puerto Real, Cadiz (Spain); Suarez-Llorens, Alfonso [Facultad de Ciencias, University of Cadiz, Avda, Rep. Saharaui s/n, 11510 Puerto Real, Cadiz (Spain); Casas-Ruiz, Melquiades; Alonso, José J.; Vidal, Juan [CEIMAR, University of Cadiz, Avda, Rep. Saharaui s/n, 11510 Puerto Real, Cádiz (Spain)

2017-05-11

A generic theoretical methodology for the calculation of the efficiency of gamma spectrometry systems is introduced in this work. The procedure is valid for any type of source and detector and can be applied to determine the full energy peak and the total efficiency of any source-detector system. The methodology is based on the idea of underlying probability of detection, which describes the physical model for the detection of the gamma radiation at the particular studied situation. This probability depends explicitly on the direction of the gamma radiation, allowing the use of this dependence the development of more realistic and complex models than the traditional models based on the point source integration. The probability function that has to be employed in practice must reproduce the relevant characteristics of the detection process occurring at the particular studied situation. Once the probability is defined, the efficiency calculations can be performed in general by using numerical methods. Monte Carlo integration procedure is especially useful to perform the calculations when complex probability functions are used. The methodology can be used for the direct determination of the efficiency and also for the calculation of corrections that require this determination of the efficiency, as it is the case of coincidence summing, geometric or self-attenuation corrections. In particular, we have applied the procedure to obtain some of the classical self-attenuation correction factors usually employed to correct for the sample attenuation of cylindrical geometry sources. The methodology clarifies the theoretical basis and approximations associated to each factor, by making explicit the probability which is generally hidden and implicit to each model. It has been shown that most of these self-attenuation correction factors can be derived by using a common underlying probability, having this probability a growing level of complexity as it reproduces more precisely

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

Science.gov (United States)

Palmans, H; Al-Sulaiti, L; Andreo, P; Shipley, D; Lühr, A; Bassler, N; Martinkovič, J; Dobrovodský, 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 + 0.0024·zw-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 + 0.0024·zw-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

Investigation of electron-loss and photon scattering correction factors for FAC-IR-300 ionization chamber

Science.gov (United States)

Mohammadi, S. M.; Tavakoli-Anbaran, H.; Zeinali, H. Z.

2017-02-01

The parallel-plate free-air ionization chamber termed FAC-IR-300 was designed at the Atomic Energy Organization of Iran, AEOI. This chamber is used for low and medium X-ray dosimetry on the primary standard level. In order to evaluate the air-kerma, some correction factors such as electron-loss correction factor (ke) and photon scattering correction factor (ksc) are needed. ke factor corrects the charge loss from the collecting volume and ksc factor corrects the scattering of photons into collecting volume. In this work ke and ksc were estimated by Monte Carlo simulation. These correction factors are calculated for mono-energy photon. As a result of the simulation data, the ke and ksc values for FAC-IR-300 ionization chamber are 1.0704 and 0.9982, respectively.

Analytic representation of the backscatter correction factor at the exit of high energy photon beams

International Nuclear Information System (INIS)

Kappas, K.; Rosenwald, J.C.

1991-01-01

In high-energy X-ray beams, the dose calculated near the exit surface under electronic equilibrium conditions is generally over-estimated since it is derived from measurements performed in water with large thickness of backscattering material. The resulting error depends on a number of parameters such as beam energy, field dimension, thickness of overlying and underlying material. The authors have systematically measured for 4 different energies and for different para- meters and for different combinations of the above parameters, the reduction of dose due to backscatter. This correction is expressed as a multiplicative factor, called 'Backscatter Correction Factor' (BCF). This BCF is larger for lower energies, larger field sizes and larger depths. The BCF has been represented by an analytical expression which involves an exponential function of the backscattering thickness and linear relationships with depth field size and beam quality index. Using this expression, the BCF can be calculated within 0.5% for any conditions in the energy range investigated. (author). 14 refs.; 4 figs.; 3 tabs

Correction factors for assessing immersion suits under harsh conditions.

Science.gov (United States)

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. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Leaked filters for energetic and angular dependence corrections of thermoluminescent response

International Nuclear Information System (INIS)

Manzoli, Jose Eduardo; Shammas, Gabriel Issa Jabra; Campos, Vicente de Paulo de

2007-01-01

Many thermoluminescent materials has been developed and used for photon personal dosimetry but no one has all desired characteristics alone. These characteristics include robustness, high sensitivity, energy photon independence, large range of photon energy detection, good reproducibility and small fading. The phosphors advantages begin to be more required and its disadvantages have became more apparent, in a global market more and more competitive. Calcium Sulfate Dysprosium doped (CaSO 4 :Dy) and Calcium Fluoride Manganese doped (CaF 2 :Mn) phosphor Thermoluminescent Dosimeters (TLDs) have been used by many laboratories. They are used in environmental and area monitoring, once they present more sensibility than other phosphors, like LiF:Mg. Theirs main disadvantage is the strong energetic dependence response, which must be corrected for theirs application in routine, where the kind of photon radiation is unknown a priori. An interesting way to make this correction is to interject a leaked filter between the beam and the phosphor, where the beam could strike the phosphor at any angle. In order to reduce the energetic dependence on any incidence angle, this work presents experimental and simulation studies on some filter geometries. It was made TL readings and simulations on TL responses to photon irradiations with gamma rays of 60 Co and X-rays of 33; 48 and 118 keV, on many incidence angles from zero to ninety degrees. The results pointed out the best filter thicknesses and widths, in order to optimize the correction of energetic dependence for the studied geometries. (author)

Attenuation correction factors for cylindrical, disc and box geometry

International Nuclear Information System (INIS)

Agarwal, Chhavi; Poi, Sanhita; Mhatre, Amol; Goswami, A.; Gathibandhe, M.

2009-01-01

In the present study, attenuation correction factors have been experimentally determined for samples having cylindrical, disc and box geometry and compared with the attenuation correction factors calculated by Hybrid Monte Carlo (HMC) method [ C. Agarwal, S. Poi, A. Goswami, M. Gathibandhe, R.A. Agrawal, Nucl. Instr. and. Meth. A 597 (2008) 198] and with the near-field and far-field formulations available in literature. It has been observed that the near-field formulae, although said to be applicable at close sample-detector geometry, does not work at very close sample-detector configuration. The advantage of the HMC method is that it is found to be valid for all sample-detector geometries.

Investigation of electron-loss and photon scattering correction factors for FAC-IR-300 ionization chamber

International Nuclear Information System (INIS)

Mohammadi, S.M.; Tavakoli-Anbaran, H.; Zeinali, H.Z.

2017-01-01

The parallel-plate free-air ionization chamber termed FAC-IR-300 was designed at the Atomic Energy Organization of Iran, AEOI. This chamber is used for low and medium X-ray dosimetry on the primary standard level. In order to evaluate the air-kerma, some correction factors such as electron-loss correction factor (k e ) and photon scattering correction factor (k sc ) are needed. k e factor corrects the charge loss from the collecting volume and k sc factor corrects the scattering of photons into collecting volume. In this work k e and k sc were estimated by Monte Carlo simulation. These correction factors are calculated for mono-energy photon. As a result of the simulation data, the k e and k sc values for FAC-IR-300 ionization chamber are 1.0704 and 0.9982, respectively.

Power factor correction (PFC) converters feeding brushless DC ...

African Journals Online (AJOL)

DR OKE

1Department of Electrical Engineering, Indian Institute of Technology Delhi, INDIA ... Hence, power factor correction (PFC) converters are used for achieving a unity ...... He is currently working as a Systems Engineer (Power IC) in AvantGarde ...

Electron fluence correction factors for various materials in clinical electron beams

International Nuclear Information System (INIS)

Olivares, M.; Blois, F. de; Podgorsak, E.B.; Seuntjens, J.P.

2001-01-01

correction factors for open electron beams are approximately proportional to the electron density of the phantom material and only weakly dependent on electron beam energy

Application of workplace correction factors to dosemeter results for the assessment of personal doses at nuclear facilities

International Nuclear Information System (INIS)

Lindborg, L.; Bolognese-Milsztajn, T.; Boschung, M.; Coeck, M.; Curzio, G.; D'Errico, F.; Fiechtner, A.; Hallfarth, D.; Lievens, B.; Lillhoek, J. E.; Loevefors-Daun, A.; Lacoste, V.; Luszik-Bhadra, M.; Reginatto, M.; Schuhmacher, H.; Tanner, R.; Vanhavere, F.

2007-01-01

Ratios of H p (10) and H*(10) were determined with reference instruments in a number of workplace fields within the nuclear industry and used to derive workplace-specific correction factors. When commercial survey meter results together with these factors were applied to the results of the locally used personal dosemeters their results improved and became within 0.7 and 1.7 of the reference values or better depending on the response of the survey meter. A similar result was obtained when a correction was determined with a prototype reference instrument for H p (10) after adjustment of its response. Commercially available survey instruments both for photon and neutron H*(10) measurements agreed with the reference instruments in most cases to within 0.5-1.5. Those conclusions are derived from results reported within the EC supported EVIDOS contract. (authors)

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

Science.gov (United States)

2010-02-03

... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration 49 CFR Parts...: Control Room Management/Human Factors, Correction AGENCY: Pipeline and Hazardous Materials Safety... following correcting amendments: PART 192--TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM...

Resistivity Correction Factor for the Four-Probe Method: Experiment I

Science.gov (United States)

Yamashita, Masato; Yamaguchi, Shoji; Enjoji, Hideo

1988-05-01

Experimental verification of the theoretically derived resistivity correction factor (RCF) is presented. Resistivity and sheet resistance measurements by the four-probe method are made on three samples: isotropic graphite, ITO film and Au film. It is indicated that the RCF can correct the apparent variations of experimental data to yield reasonable resistivities and sheet resistances.

Volume corrections factors in the measurement of 99mTc and 123I activities in radionuclide calibrators

International Nuclear Information System (INIS)

Correia, Amanda Ribeiro; Rezende, Eduarda Alexandre; Iwahara, Akira; Oliveira, Antonio Eduardo de; Oliveira, Estela Maria de; Tauhata, Luiz; Chaves, Taina Olivieri

2012-01-01

To determine correction factors for the variation in volume of radiopharmaceuticals in containers of different geometries, comparing the influence of such factors on the determination of 99m Tc and 123 I activity with two types of calibrators - one with ionization chamber and another with Geiger-Mueller (G-M) detector -; and to evaluate calibrators performance in the measurement of 99m Tc and 1 '2 3 I activities. Materials and Methods: Eight calibrators, 10R glass vials, 3 and 5 mL plastic syringes and 99m Tc and 123 I solutions were utilized. The correction factors were determined with basis on practical measurements of the variation in the calibrators' response according to the volume of radionuclide solution in the glass vials. The performance was evaluated according to the acceptance criterion of +- 10% accuracy required by the Brazilian standard. Results: The variation of the calibrators' response according to the variation in radionuclide volume was reasonably greater in the calibrator with G-M detector. It was also greater for 123 I than for 99m Tc. Conclusion: The results confirm that the calibrators' response depends on the radionuclide volume contained in the vials. Such dependence is more critical for the calibrators equipped with G-M detector and for 123 I as compared with 99m Tc. (author)

Power factor correction (PFC) converters feeding brushless DC ...

African Journals Online (AJOL)

This paper presents a comprehensive study of power factor correction (PFC) converters for feeding brushless DC (BLDC) motor drive. This work explores various configurations of PFC converters which are classified into five different categories of non-isolated, bridgeless (BL) non-isolated, isolated, BL-isolated PFC ...

TH-AB-201-08: Ion Chamber Dose Measurements - Problems with the Temperature-Pressure Correction Factor

Energy Technology Data Exchange (ETDEWEB)

Bourgouin, A [Carleton University, Ottawa, Ontario (Canada); McEwen, M [National Research Council, Ottawa, ON (Canada)

2016-06-15

Purpose: To investigate the behavior of ionization chambers over a wide pressure range. Methods: Three cylindrical and two parallel-plate designs of ion chamber were investigated. The ion chambers were placed in vessel where the pressure was varied from atmospheric (101 kPa) down to 5 kPa. Measurements were made using 60Co and high-energy electron beams. The pressure was measured to better than 0.1% and multiple data sets were obtained for each chamber at both polarities to investigate pressure cycling and dependency on the sign of the charge collected. Results: For all types of chamber, the ionization current, corrected using the standard PTP, showed a similar behaviour. Deviations from the standard theory were generally small for Co-60 but very significant for electron beams, up to 20 % below P = 10 kPa. The effect was found to be always larger when collecting negative charge, suggesting a dependence on free-electron collection. The most likely source of such electrons is low-energy electrons emitted from the electrodes. This signal would be independent of air pressure within the chamber cavity. The data was analyzed to extract this signal and it was found to be a non-negligible component of the ionization current at atmospheric pressure. In the case of the parallel plate chambers, the effect was approximately 0.25 %. For the cylindrical chambers the effect was larger - up to 1.2 % - and dependent on the chamber type, which would be consistent with electron emission from different wall materials. For the electron beams, the correction factor was dependent on the electron energy and approximately double that observed in 60Co. Conclusion: Measurements have indicated significant deviations of the standard pressure correction that are consistent with electron emission from chamber electrodes. This has implications for both primary standard and reference ion chamber-based dosimetry.

Higgs mass dependence of electroweak radiative corrections and the triviality bound

NARCIS (Netherlands)

Cortese, S.; Pallante, E.; Petronzio, R.

1993-01-01

We discuss how the existence of a triviality bound for the Higgs sector of the standard model does influence the dependence of radiative corrections upon the Higgs mass. The lowering of the Landau pole with increasing Higgs mass implies that the sensitivity to Higgs mass values beyond ≈ 500 GeV is

Correction factors for photon beam quality for cylindrical ionization chambers: Monte Carlo calculations by using the PENELOPE code

International Nuclear Information System (INIS)

Barreras Caballero, A. A.; Hernandez Garcia, J.J.; Alfonso Laguardia, R.

2009-01-01

Were directly determined correction factors depending on the type camera beam quality, k, Q, and kQ, Qo, instead of the product (w, air p) Q, for three type cylindrical ionization chambers Pinpoint and divergent monoenergetic beams of photons in a wide range of energies (4-20 MV). The method of calculation used dispenses with the approaches taken in the classic procedure considered independent of braking power ratios and the factors disturbance of the camera. A detailed description of the geometry and materials chambers were supplied by the manufacturer and used as data input for the system 2006 of PENELOPE Monte Carlo calculation using a User code that includes correlated sampling, and forced interactions division of particles. We used a photon beam Co-60 as beam reference for calculating the correction factors for beam quality. No data exist for the cameras PTW 31014, 31015 and 31016 in the TRS-398 at they do not compare the results with data calculated or determined experimentally by other authors. (author)

Topographic Correction Module at Storm (TC@Storm)

Science.gov (United States)

Zaksek, K.; Cotar, K.; Veljanovski, T.; Pehani, P.; Ostir, K.

2015-04-01

Different solar position in combination with terrain slope and aspect result in different illumination of inclined surfaces. Therefore, the retrieved satellite data cannot be accurately transformed to the spectral reflectance, which depends only on the land cover. The topographic correction should remove this effect and enable further automatic processing of higher level products. The topographic correction TC@STORM was developed as a module within the SPACE-SI automatic near-real-time image processing chain STORM. It combines physical approach with the standard Minnaert method. The total irradiance is modelled as a three-component irradiance: direct (dependent on incidence angle, sun zenith angle and slope), diffuse from the sky (dependent mainly on sky-view factor), and diffuse reflected from the terrain (dependent on sky-view factor and albedo). For computation of diffuse irradiation from the sky we assume an anisotropic brightness of the sky. We iteratively estimate a linear combination from 10 different models, to provide the best results. Dependent on the data resolution, we mask shades based on radiometric (image) or geometric properties. The method was tested on RapidEye, Landsat 8, and PROBA-V data. Final results of the correction were evaluated and statistically validated based on various topography settings and land cover classes. Images show great improvements in shaded areas.

Importance of Lorentz structure in the parton model: Target mass corrections, transverse momentum dependence, positivity bounds

International Nuclear Information System (INIS)

D'Alesio, U.; Leader, E.; Murgia, F.

2010-01-01

We show that respecting the underlying Lorentz structure in the parton model has very strong consequences. Failure to insist on the correct Lorentz covariance is responsible for the existence of contradictory results in the literature for the polarized structure function g 2 (x), whereas with the correct imposition we are able to derive the Wandzura-Wilczek relation for g 2 (x) and the target-mass corrections for polarized deep inelastic scattering without recourse to the operator product expansion. We comment briefly on the problem of threshold behavior in the presence of target-mass corrections. Careful attention to the Lorentz structure has also profound implications for the structure of the transverse momentum dependent parton densities often used in parton model treatments of hadron production, allowing the k T dependence to be derived explicitly. It also leads to stronger positivity and Soffer-type bounds than usually utilized for the collinear densities.

Refined shear correction factor for very thick simply supported and uniformly loaded isosceles right triangular auxetic plates

International Nuclear Information System (INIS)

Lim, Teik-Cheng

2016-01-01

For moderately thick plates, the use of First order Shear Deformation Theory (FSDT) with a constant shear correction factor of 5/6 is sufficient to take into account the plate deflection arising from transverse shear deformation. For very thick plates, the use of Third order Shear Deformation Theory (TSDT) is preferred as it allows the shear strain distribution to be varied through the plate thickness. Therefore no correction factor is required in TSDT, unlike FSDT. Due to the complexity involved in TSDT, this paper obtains a more accurate shear correction factor for use in FSDT of very thick simply supported and uniformly loaded isosceles right triangular plates based on the TSDT. By matching the maximum deflections for this plate according to FSDT and TSDT, a variable shear correction factor is obtained. Results show that the shear correction factor for the simplified TSDT, i.e. 14/17, is least accurate. The commonly adopted shear correction factor of 5/6 in FSDT is valid only for very thin or highly auxetic plates. This paper provides a variable shear correction for FSDT deflection that matches the plate deflection by TSDT. This variable shear correction factor allows designers to justify the use of a commonly adopted shear correction factor of 5/6 even for very thick plates as long as the Poisson’s ratio of the plate material is sufficiently negative. (paper)

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

Science.gov (United States)

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

Empirical Derivation of Correction Factors for Human Spiral Ganglion Cell Nucleus and Nucleolus Count Units.

Science.gov (United States)

Robert, Mark E; Linthicum, Fred H

2016-01-01

Profile count method for estimating cell number in sectioned tissue applies a correction factor for double count (resulting from transection during sectioning) of count units selected to represent the cell. For human spiral ganglion cell counts, we attempted to address apparent confusion between published correction factors for nucleus and nucleolus count units that are identical despite the role of count unit diameter in a commonly used correction factor formula. We examined a portion of human cochlea to empirically derive correction factors for the 2 count units, using 3-dimensional reconstruction software to identify double counts. The Neurotology and House Histological Temporal Bone Laboratory at University of California at Los Angeles. Using a fully sectioned and stained human temporal bone, we identified and generated digital images of sections of the modiolar region of the lower first turn of cochlea, identified count units with a light microscope, labeled them on corresponding digital sections, and used 3-dimensional reconstruction software to identify double-counted count units. For 25 consecutive sections, we determined that double-count correction factors for nucleus count unit (0.91) and nucleolus count unit (0.92) matched the published factors. We discovered that nuclei and, therefore, spiral ganglion cells were undercounted by 6.3% when using nucleolus count units. We determined that correction factors for count units must include an element for undercounting spiral ganglion cells as well as the double-count element. We recommend a correction factor of 0.91 for the nucleus count unit and 0.98 for the nucleolus count unit when using 20-µm sections. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

Improvements to the Chebyshev expansion of attenuation correction factors for cylindrical samples

International Nuclear Information System (INIS)

Mildner, D.F.R.; Carpenter, J.M.

1990-01-01

The accuracy of the Chebyshev expansion coefficients used for the calculation of attenuation correction factors for cylinderical samples has been improved. An increased order of expansion allows the method to be useful over a greater range of attenuation. It is shown that many of these coefficients are exactly zero, others are rational numbers, and others are rational frations of π -1 . The assumptions of Sears in his asymptotic expression of the attenuation correction factor are also examined. (orig.)

The effect of correction factors on internal bremsstrahlung spectrum

International Nuclear Information System (INIS)

Elias, M.M.

1985-01-01

Correction factors affecting the experimental spectrum of internal bremsstrahlung (IB) accompanying B-decay have been studied. A wide survey of previous experimental studies, show a discrepancy between experimental results and the available theories of IB production especially for heavy nuclides and forbidden B-transitions, with some agreement in bounded regions in IB spectrum. This is due to the uncertainity in evaluating correction factors and neglecting others. The experimental distributions of IB from 147 Pm, 204 Tl and 90 Y are measured by using two different crystals of NaI(Tl) scintillators (2''x2'' and 3'''x3'') with suitable geometrical arrangements designed to minimize the effect of several factors. The present study covers overlapped ranges of energy from 0.05 to 2.2 MeV to observe the effect of these factors along this wide region of energy. The experimental probabilities are compared with theories. It agrees fairly well with Lewis and Ford theory in case of 14 '7Pm, 204 Tl, and with detour transitions theory in the intermediate region of energies of IB spectrum from 90 Y. Deviation of our results from theories is less than all previous experimental work. 20 tabs.; 43 figs.; 84 refs.; 5 apps

SU-E-T-552: Monte Carlo Calculation of Correction Factors for a Free-Air Ionization Chamber in Support of a National Air-Kerma Standard for Electronic Brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Mille, M; Bergstrom, P [National Institute of Standards and Technology, Gaithersburg, MD (United States)

2015-06-15

Purpose: To use Monte Carlo radiation transport methods to calculate correction factors for a free-air ionization chamber in support of a national air-kerma standard for low-energy, miniature x-ray sources used for electronic brachytherapy (eBx). Methods: The NIST is establishing a calibration service for well-type ionization chambers used to characterize the strength of eBx sources prior to clinical use. The calibration approach involves establishing the well-chamber’s response to an eBx source whose air-kerma rate at a 50 cm distance is determined through a primary measurement performed using the Lamperti free-air ionization chamber. However, the free-air chamber measurements of charge or current can only be related to the reference air-kerma standard after applying several corrections, some of which are best determined via Monte Carlo simulation. To this end, a detailed geometric model of the Lamperti chamber was developed in the EGSnrc code based on the engineering drawings of the instrument. The egs-fac user code in EGSnrc was then used to calculate energy-dependent correction factors which account for missing or undesired ionization arising from effects such as: (1) attenuation and scatter of the x-rays in air; (2) primary electrons escaping the charge collection region; (3) lack of charged particle equilibrium; (4) atomic fluorescence and bremsstrahlung radiation. Results: Energy-dependent correction factors were calculated assuming a monoenergetic point source with the photon energy ranging from 2 keV to 60 keV in 2 keV increments. Sufficient photon histories were simulated so that the Monte Carlo statistical uncertainty of the correction factors was less than 0.01%. The correction factors for a specific eBx source will be determined by integrating these tabulated results over its measured x-ray spectrum. Conclusion: The correction factors calculated in this work are important for establishing a national standard for eBx which will help ensure that dose

Monte Carlo correction factors for a Farmer 0.6 cm3 ion chamber dose measurement in the build-up region of the 6 MV clinical beam

International Nuclear Information System (INIS)

Pena, J; Sanchez-Doblado, F; Capote, R; Terron, J A; Gomez, F

2006-01-01

Reference dosimetry of photon fields is a well-established subject and currently available protocols (such as the IAEA TRS-398 and AAPM TG-51) provide methods for converting the ionization chamber (IC) reading into dose to water, provided reference conditions of charged particle equilibrium (CPE) are fulfilled. But these protocols cannot deal with the build-up region, where the lack of CPE limits the applicability of the cavity theorems and so the chamber correction factors become depth dependent. By explicitly including the IC geometry in the Monte Carlo simulations, depth-dependent dose correction factors are calculated for a PTW 30001 0.6 cm 3 ion chamber in the build-up region of the 6 MV photon beam. The corrected percentage depth dose (PDD) agrees within 2% with that measured using the NACP 02 plane-parallel ion chamber in the build-up region at depths greater than 0.4 cm, where the Farmer chamber wall reaches the phantom surface

Correction of a Depth-Dependent Lateral Distortion in 3D Super-Resolution Imaging.

Directory of Open Access Journals (Sweden)

Lina Carlini

Full Text Available Three-dimensional (3D localization-based super-resolution microscopy (SR requires correction of aberrations to accurately represent 3D structure. Here we show how a depth-dependent lateral shift in the apparent position of a fluorescent point source, which we term `wobble`, results in warped 3D SR images and provide a software tool to correct this distortion. This system-specific, lateral shift is typically > 80 nm across an axial range of ~ 1 μm. A theoretical analysis based on phase retrieval data from our microscope suggests that the wobble is caused by non-rotationally symmetric phase and amplitude aberrations in the microscope's pupil function. We then apply our correction to the bacterial cytoskeletal protein FtsZ in live bacteria and demonstrate that the corrected data more accurately represent the true shape of this vertically-oriented ring-like structure. We also include this correction method in a registration procedure for dual-color, 3D SR data and show that it improves target registration error (TRE at the axial limits over an imaging depth of 1 μm, yielding TRE values of < 20 nm. This work highlights the importance of correcting aberrations in 3D SR to achieve high fidelity between the measurements and the sample.

Power Factor Correction for Thyristor Equipment in Glass Industry ...

African Journals Online (AJOL)

Thyristor power controllers are now widely used in the glass industry for controlling furnace temperature. While offering a number of operational advantages, they operate at lagging power factors which require correction for minimum power cost. Harmonic resonance with the utility feed, however, complicate the use of ...

Relationship between γ detection dead-time and count correction factor

International Nuclear Information System (INIS)

Wu Huailong; Zhang Jianhua; Chu Chengsheng; Hu Guangchun; Zhang Changfan; Hu Gen; Gong Jian; Tian Dongfeng

2015-01-01

The relationship between dead-time and count correction factor was investigated by using interference source for purpose of high γ activity measurement. The count rates maintain several 10 s"-"l with γ energy of 0.3-1.3 MeV for 10"4-10"5 Bq radioactive source. It is proved that the relationship between count loss and dead-time is unconcerned at various energy and various count intensities. The same correction formula can be used for any nuclide measurement. (authors)

Monte Carlo study of correction factors for the use of plastic phantoms in clinical electron dosimetry

International Nuclear Information System (INIS)

Araki, Fujio

2007-01-01

In some recent dosimetry protocols, plastic is allowed as a phantom material for the determination of an absorbed dose to water in electron beams, especially for low energy with beam qualities R 50 2 . In electron dosimetry with plastic, a depth-scaling factor, c pl , and a chamber-dependent fluence correction factor, h pl , are needed to convert the dose measured at a water-equivalent reference depth in plastic to a dose at a reference depth in water. The purpose of this study is to calculate correction factors for the use of plastic phantoms for clinical electron dosimetry using the EGSnrc Monte Carlo code system. RMI-457 and WE-211 were investigated as phantom materials. First the c pl values for plastic materials were calculated as a function of a half-value depth of maximum ionization, I 50 , in plastic. The c pl values for RMI-457 and WE-211 varied from 0.992 to 1.002 and from 0.971 to 0.979, respectively, in a range of nominal energies from 4 MeV to 18 MeV, and varied slightly as a function of I 50 in plastic. Since h pl values depend on the wall correction factor, P wall , of the chamber used, they are evaluated using a pure electron fluence correction factor, φ pl w , and P wall w and P wall pl for a combination of water or plastic phantoms and plane-parallel ionization chambers (NACP-02, Markus and Roos). The φ pl w and P wall (P wall w and P wall pl ) values were calculated as a function of the water-equivalent depth in plastic materials and at a reference depth as a function of R 50 in water, respectively. The φ pl w values varied from 1.024 at 4 MeV to 1.013 at 18 MeV for RMI-457, and from 1.025 to 1.016 for WE-211. P wall w values for plane-parallel chambers showed values in the order of 1.5% to 2% larger than unity at 4 MeV, consistent with earlier results. The P wall pl values of RMI-457 and WE-211 were close to unity for all the energy beams. Finally, calculated h pl values of RMI-457 ranged from 1.009 to 1.005, from 1.010 to 1.003 and from 1

Determination of true coincidence correction factors using Monte-Carlo simulation techniques

Directory of Open Access Journals (Sweden)

Chionis Dionysios A.

2014-01-01

Full Text Available Aim of this work is the numerical calculation of the true coincidence correction factors by means of Monte-Carlo simulation techniques. For this purpose, the Monte Carlo computer code PENELOPE was used and the main program PENMAIN was properly modified in order to include the effect of the true coincidence phenomenon. The modified main program that takes into consideration the true coincidence phenomenon was used for the full energy peak efficiency determination of an XtRa Ge detector with relative efficiency 104% and the results obtained for the 1173 keV and 1332 keV photons of 60Co were found consistent with respective experimental ones. The true coincidence correction factors were calculated as the ratio of the full energy peak efficiencies was determined from the original main program PENMAIN and the modified main program PENMAIN. The developed technique was applied for 57Co, 88Y, and 134Cs and for two source-to-detector geometries. The results obtained were compared with true coincidence correction factors calculated from the "TrueCoinc" program and the relative bias was found to be less than 2%, 4%, and 8% for 57Co, 88Y, and 134Cs, respectively.

Relativistic and QED corrections to the g factor of Li-like ions

International Nuclear Information System (INIS)

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

2004-01-01

Calculations of various corrections to the g factor of Li-like ions are presented, which result in a significant improvement of the theoretical accuracy in the region Z=6-92. The configuration-interaction Dirac-Fock method is employed for the evaluation of the interelectronic-interaction correction of order 1/Z 2 and higher. This correction is combined with the 1/Z interelectronic-interaction term derived within a rigorous QED approach. The one-electron QED correction of first order in α is obtained by employing our recent results for the self-energy term and by evaluating the vacuum-polarization contribution. The screening of QED corrections is taken into account to the leading orders in αZ and 1/Z

Improved scatter correction with factor analysis for planar and SPECT imaging

Science.gov (United States)

Knoll, Peter; Rahmim, Arman; Gültekin, Selma; Šámal, Martin; Ljungberg, Michael; Mirzaei, Siroos; Segars, Paul; Szczupak, Boguslaw

2017-09-01

Quantitative nuclear medicine imaging is an increasingly important frontier. In order to achieve quantitative imaging, various interactions of photons with matter have to be modeled and compensated. Although correction for photon attenuation has been addressed by including x-ray CT scans (accurate), correction for Compton scatter remains an open issue. The inclusion of scattered photons within the energy window used for planar or SPECT data acquisition decreases the contrast of the image. While a number of methods for scatter correction have been proposed in the past, in this work, we propose and assess a novel, user-independent framework applying factor analysis (FA). Extensive Monte Carlo simulations for planar and tomographic imaging were performed using the SIMIND software. Furthermore, planar acquisition of two Petri dishes filled with 99mTc solutions and a Jaszczak phantom study (Data Spectrum Corporation, Durham, NC, USA) using a dual head gamma camera were performed. In order to use FA for scatter correction, we subdivided the applied energy window into a number of sub-windows, serving as input data. FA results in two factor images (photo-peak, scatter) and two corresponding factor curves (energy spectra). Planar and tomographic Jaszczak phantom gamma camera measurements were recorded. The tomographic data (simulations and measurements) were processed for each angular position resulting in a photo-peak and a scatter data set. The reconstructed transaxial slices of the Jaszczak phantom were quantified using an ImageJ plugin. The data obtained by FA showed good agreement with the energy spectra, photo-peak, and scatter images obtained in all Monte Carlo simulated data sets. For comparison, the standard dual-energy window (DEW) approach was additionally applied for scatter correction. FA in comparison with the DEW method results in significant improvements in image accuracy for both planar and tomographic data sets. FA can be used as a user

SU-F-T-67: Correction Factors for Monitor Unit Verification of Clinical Electron Beams

Energy Technology Data Exchange (ETDEWEB)

Haywood, J [Mercy Health Partners, Muskegon, MI (United States)

2016-06-15

Purpose: Monitor units calculated by electron Monte Carlo treatment planning systems are often higher than TG-71 hand calculations for a majority of patients. Here I’ve calculated tables of geometry and heterogeneity correction factors for correcting electron hand calculations. Method: A flat water phantom with spherical volumes having radii ranging from 3 to 15 cm was created. The spheres were centered with respect to the flat water phantom, and all shapes shared a surface at 100 cm SSD. D{sub max} dose at 100 cm SSD was calculated for each cone and energy on the flat phantom and for the spherical volumes in the absence of the flat phantom. The ratio of dose in the sphere to dose in the flat phantom defined the geometrical correction factor. The heterogeneity factors were then calculated from the unrestricted collisional stopping power for tissues encountered in electron beam treatments. These factors were then used in patient second check calculations. Patient curvature was estimated by the largest sphere that aligns to the patient contour, and appropriate tissue density was read from the physical properties provided by the CT. The resulting MU were compared to those calculated by the treatment planning system and TG-71 hand calculations. Results: The geometry and heterogeneity correction factors range from ∼(0.8–1.0) and ∼(0.9–1.01) respectively for the energies and cones presented. Percent differences for TG-71 hand calculations drop from ∼(3–14)% to ∼(0–2)%. Conclusion: Monitor units calculated with the correction factors typically decrease the percent difference to under actionable levels, < 5%. While these correction factors work for a majority of patients, there are some patient anatomies that do not fit the assumptions made. Using these factors in hand calculations is a first step in bringing the verification monitor units into agreement with the treatment planning system MU.

Neutron activation analysis of copper traces: a study for sodium correction factor

International Nuclear Information System (INIS)

Tripathi, A.B.R.; Bhadkambekar, C.A.; Basu, A.K.; Chattopadhyay, N.

2007-01-01

Peak ratio correction factors for accurate quantitative determination of copper by NAA via 64 Cu radioisotope in presence of high 24 Na radioactivities has been established. Copper is the principal element as a marker of bullet residues on targets in connection to forensic ballistics cases. Reliable and precise estimation of copper by NAA either via non-destructive way or by resorting to radiochemical separation is of importance in forensic analysis for arriving at definitive inferences. However, majority of samples originating from wearing apparels, paper, leather, skin, glass or any other metal exhibit matrices contain high levels of sodium. The NAA scheme for determination of copper rests on measurements of net counts at 511 KeV which is the positron annihilation peak of 64 Cu. 24 Na also contributes significantly exactly at 511 KeV of gamma energy albeit by different mechanism i.e., by pair production. Therefore, total signal at 511 KeV is contributed by both. The easiest approach for correct estimation of copper traces has been established by the peak ratio correction factor. This has significance as both 64 Cu and 24 Na have comparable half lives, hence, as such time gap measurements cannot improve the situation. The consistency of peak ratio correction factor could be established for a particular geometry. (author)

Factors influencing workplace violence risk among correctional health workers: insights from an Australian survey.

Science.gov (United States)

Cashmore, Aaron W; Indig, Devon; Hampton, Stephen E; Hegney, Desley G; Jalaludin, Bin B

2016-11-01

Little is known about the environmental and organisational determinants of workplace violence in correctional health settings. This paper describes the views of health professionals working in these settings on the factors influencing workplace violence risk. All employees of a large correctional health service in New South Wales, Australia, were invited to complete an online survey. The survey included an open-ended question seeking the views of participants about the factors influencing workplace violence in correctional health settings. Responses to this question were analysed using qualitative thematic analysis. Participants identified several factors that they felt reduced the risk of violence in their workplace, including: appropriate workplace health and safety policies and procedures; professionalism among health staff; the presence of prison guards and the quality of security provided; and physical barriers within clinics. Conversely, participants perceived workplace violence risk to be increased by: low health staff-to-patient and correctional officer-to-patient ratios; high workloads; insufficient or underperforming security staff; and poor management of violence, especially horizontal violence. The views of these participants should inform efforts to prevent workplace violence among correctional health professionals.

Self-Excited Single-Stage Power Factor Correction Driving Circuit for LED Lighting

Directory of Open Access Journals (Sweden)

Yong-Nong Chang

2014-01-01

Full Text Available This pa\tper proposes a self-excited single-stage high power factor LED lighting driving circuit. Being featured with power factor correction capability without needing any control devices, the proposed circuit structure is with low cost and suitable for commercial production. The power factor correction function is accomplished by using inductor in combination with a half-bridge quasi resonant converter to achieve active switching and yield out voltage regulation according to load requirement. Furthermore, the zero-voltage switching in the half-bridge converter can be attained to promote the overall performance efficiency of the proposed circuit. Finally, the validity and production availability of the proposed circuit will be verified as well.

1/mQ corrections to form factors and extraction of |Vcb|

International Nuclear Information System (INIS)

Liu, J.; Chao, K.

1997-01-01

Form factors for 0 - →0 - and 0 - →1 - mesonic transitions in the heavy quark limit and the 1/m Q corrections are analyzed model independently within the Bethe-Salpeter (BS) formalism. The analysis shows that the BS formalism has spin-flavor symmetry in the heavy quark limit and respects Luke's theorem when the 1/m Q corrections are taken into account. All form factors for B→D (*) transitions beyond the zero recoil point are estimated in a relativistic constituent quark model based on the BS formalism. Using these form factors we calculate the branching ratios for the semileptonic decays B→D (*) l + ν l and extract the Cabibbo-Kobayashi-Maskawa matrix element |V cb |. We get |V cb |=0.042±0.003 which is consistent with the current world average. copyright 1997 The American Physical Society

Impact of hadronic and nuclear corrections on global analysis of spin-dependent parton distributions

Energy Technology Data Exchange (ETDEWEB)

Jimenez-Delgado, Pedro [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Accardi, Alberto [Hampton University, Hampton, VA (United States); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Melnitchouk, Wally [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2014-02-01

We present the first results of a new global next-to-leading order analysis of spin-dependent parton distribution functions from the most recent world data on inclusive polarized deep-inelastic scattering, focusing in particular on the large-x and low-Q^2 regions. By directly fitting polarization asymmetries we eliminate biases introduced by using polarized structure function data extracted under nonuniform assumptions for the unpolarized structure functions. For analysis of the large-x data we implement nuclear smearing corrections for deuterium and 3He nuclei, and systematically include target mass and higher twist corrections to the g_1 and g_2 structure functions at low Q^2. We also explore the effects of Q^2 and W^2 cuts in the data sets, and the potential impact of future data on the behavior of the spin-dependent parton distributions at large x.

A proposed parameterization of interface discontinuity factors depending on neighborhood for pin-by-pin diffusion computations for LWR

International Nuclear Information System (INIS)

Herrero, Jose Javier; Garcia-Herranz, Nuria; Ahnert, Carol

2011-01-01

There exists an interest in performing full core pin-by-pin computations for present nuclear reactors. In such type of problems the use of a transport approximation like the diffusion equation requires the introduction of correction parameters. Interface discontinuity factors can improve the diffusion solution to nearly reproduce a transport solution. Nevertheless, calculating accurate pin-by-pin IDF requires the knowledge of the heterogeneous neutron flux distribution, which depends on the boundary conditions of the pin-cell as well as the local variables along the nuclear reactor operation. As a consequence, it is impractical to compute them for each possible configuration. An alternative to generate accurate pin-by-pin interface discontinuity factors is to calculate reference values using zero-net-current boundary conditions and to synthesize afterwards their dependencies on the main neighborhood variables. In such way the factors can be accurately computed during fine-mesh diffusion calculations by correcting the reference values as a function of the actual environment of the pin-cell in the core. In this paper we propose a parameterization of the pin-by-pin interface discontinuity factors allowing the implementation of a cross sections library able to treat the neighborhood effect. First results are presented for typical PWR configurations. (author)

A proposed parameterization of interface discontinuity factors depending on neighborhood for pin-by-pin diffusion computations for LWR

Energy Technology Data Exchange (ETDEWEB)

Herrero, Jose Javier; Garcia-Herranz, Nuria; Ahnert, Carol, E-mail: herrero@din.upm.es, E-mail: nuria@din.upm.es, E-mail: carol@din.upm.es [Departamento de Ingenieria Nuclear, Universidad Politecnica de Madrid (Spain)

2011-07-01

There exists an interest in performing full core pin-by-pin computations for present nuclear reactors. In such type of problems the use of a transport approximation like the diffusion equation requires the introduction of correction parameters. Interface discontinuity factors can improve the diffusion solution to nearly reproduce a transport solution. Nevertheless, calculating accurate pin-by-pin IDF requires the knowledge of the heterogeneous neutron flux distribution, which depends on the boundary conditions of the pin-cell as well as the local variables along the nuclear reactor operation. As a consequence, it is impractical to compute them for each possible configuration. An alternative to generate accurate pin-by-pin interface discontinuity factors is to calculate reference values using zero-net-current boundary conditions and to synthesize afterwards their dependencies on the main neighborhood variables. In such way the factors can be accurately computed during fine-mesh diffusion calculations by correcting the reference values as a function of the actual environment of the pin-cell in the core. In this paper we propose a parameterization of the pin-by-pin interface discontinuity factors allowing the implementation of a cross sections library able to treat the neighborhood effect. First results are presented for typical PWR configurations. (author)

Relativistic corrections to the form factors of Bc into P-wave orbitally excited charmonium

Science.gov (United States)

Zhu, Ruilin

2018-06-01

We investigated the form factors of the Bc meson into P-wave orbitally excited charmonium using the nonrelativistic QCD effective theory. Through the analytic computation, the next-to-leading order relativistic corrections to the form factors were obtained, and the asymptotic expressions were studied in the infinite bottom quark mass limit. Employing the general form factors, we discussed the exclusive decays of the Bc meson into P-wave orbitally excited charmonium and a light meson. We found that the relativistic corrections lead to a large correction for the form factors, which makes the branching ratios of the decay channels B (Bc ± →χcJ (hc) +π± (K±)) larger. These results are useful for the phenomenological analysis of the Bc meson decays into P-wave charmonium, which shall be tested in the LHCb experiments.

Determination of correction factor of radioelement content data generated from Exploranium GR-320 Gamma spectrometer

International Nuclear Information System (INIS)

Nasrun, S; Syamsul-Hadi, M; Sumardi

2000-01-01

Gamma-ray Spectrometer Exploranium GR-320 is the instrument radiometric survey which is able to measure radioelement content directly in field based on partial gamma-ray energy of elements. Because of the instrument is new and it was granted from the lAEA, so it is necessarily to create a correction factor for the instrument due to be gaining the better data. Correction factor was generated from comparing gamma spectrometer's radioelement content to those of chemical analysed data of calibration pad. The correction factor for Potassium (K) is 1.31, uranium is 1.46, and thorium is 0.39

Sequence correction of random coil chemical shifts: correlation between neighbor correction factors and changes in the Ramachandran distribution

DEFF Research Database (Denmark)

Kjærgaard, Magnus; Poulsen, Flemming Martin

2011-01-01

Random coil chemical shifts are necessary for secondary chemical shift analysis, which is the main NMR method for identification of secondary structure in proteins. One of the largest challenges in the determination of random coil chemical shifts is accounting for the effect of neighboring residues....... The contributions from the neighboring residues are typically removed by using neighbor correction factors determined based on each residue's effect on glycine chemical shifts. Due to its unusual conformational freedom, glycine may be particularly unrepresentative for the remaining residue types. In this study, we...... in the conformational ensemble are an important source of neighbor effects in disordered proteins. Glutamine derived random coil chemical shifts and correction factors modestly improve our ability to predict (13)C chemical shifts of intrinsically disordered proteins compared to existing datasets, and may thus improve...

Deep subcritical levels measurements dependents upon kinetic distortion factors

International Nuclear Information System (INIS)

Pan Shibiao; Li Xiang; Fu Guo'en; Huang Liyuan; Mu Keliang

2013-01-01

The measurement of deep subcritical levels, with the increase of subcriticality, showed that the results impact on the kinetic distortion effect, along with neutron flux strongly deteriorated. Using the diffusion theory, calculations have been carried out to quantify the kinetic distortion correction factors in subcritical systems, and these indicate that epithermal neutron distributions are strongly affected by kinetic distortion. Subcriticality measurements in four different rod-state combination at the zero power device was carried out. The test data analysis shows that, with increasing subcriticality, kinetic distortion effect correction factor gradually increases from 1.052 to 1.065, corresponding reactive correction amount of 0.78β eff ∼ 3.01β eff . Thus, it is necessary to consider the kinetic distortion effect in the deep subcritical reactivity measurements. (authors)

Power correction to the asymptotics of the pion electromagnetic form factor

International Nuclear Information System (INIS)

Geshkenbein, B.V.; Terentyev, M.V.

1982-01-01

The contribution of the power correction approximately (μ 2 /Q 2 ) 2 enhanced by the factor approximately μ 2 /anti m 2 , to the pion form factor (FF) is calculated (here μ is the pion mass, anti m=1/2(msub(u)+msub(α)) is the mean value of the u- and d-quark masses, Q 2 =-(p-p') 2 > 0, where p, p' are meson momenta at initial and final state. It is shown that the only source of large corrections is due to the contribution of the local pseudoscalar current. The main (approximately 1/Q 2 ) asymptotics of FF associated with the axial current contribution, is derived. The contribution (approximately 1/Q 4 ) of the pseudoscalar current is calculated

Ionization chamber correction factors for MR-linacs.

Science.gov (United States)

Pojtinger, Stefan; Dohm, Oliver Steffen; Kapsch, Ralf-Peter; Thorwarth, Daniela

2018-06-07

Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor k B . The purpose of this study is to systematically investigate k B for a typical reference setup for commercially available ionization chambers with different magnetic field strengths. The Monte Carlo simulation tool EGSnrc was used to simulate eight commercially available ionization chambers in magnetic fields whose magnetic flux density was in the range of 0-2.5 T. To validate the simulation, the influence of the magnetic field was experimentally determined for a PTW30013 Farmer-type chamber for magnetic flux densities between 0 and 1.425 T. Changes in the detector response of up to 8% depending on the magnetic flux density, on the chamber geometry and on the chamber orientation were obtained. In the experimental setup, a maximum deviation of less than 2% was observed when comparing measured values with simulated values. Dedicated values for two MR-linac systems (ViewRay MRIdian, ViewRay Inc, Cleveland, United States, 0.35 T/ 6 MV and Elekta Unity, Elekta AB, Stockholm, Sweden, 1.5 T/7 MV) were determined for future use in reference dosimetry. Simulated values for thimble-type chambers are in good agreement with experiments as well as with the results of previous publications. After further experimental validation, the results can be considered for definition of standard protocols for purposes of reference dosimetry in MRgRT.

Ionization chamber correction factors for MR-linacs

Science.gov (United States)

Pojtinger, Stefan; Steffen Dohm, Oliver; Kapsch, Ralf-Peter; Thorwarth, Daniela

2018-06-01

Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor k B. The purpose of this study is to systematically investigate k B for a typical reference setup for commercially available ionization chambers with different magnetic field strengths. The Monte Carlo simulation tool EGSnrc was used to simulate eight commercially available ionization chambers in magnetic fields whose magnetic flux density was in the range of 0–2.5 T. To validate the simulation, the influence of the magnetic field was experimentally determined for a PTW30013 Farmer-type chamber for magnetic flux densities between 0 and 1.425 T. Changes in the detector response of up to 8% depending on the magnetic flux density, on the chamber geometry and on the chamber orientation were obtained. In the experimental setup, a maximum deviation of less than 2% was observed when comparing measured values with simulated values. Dedicated values for two MR-linac systems (ViewRay MRIdian, ViewRay Inc, Cleveland, United States, 0.35 T/ 6 MV and Elekta Unity, Elekta AB, Stockholm, Sweden, 1.5 T/7 MV) were determined for future use in reference dosimetry. Simulated values for thimble-type chambers are in good agreement with experiments as well as with the results of previous publications. After further experimental validation, the results can be considered for definition of standard protocols for purposes of reference dosimetry in MRgRT.

Development of the Heated Length Correction Factor

International Nuclear Information System (INIS)

Park, Ho-Young; Kim, Kang-Hoon; Nahm, Kee-Yil; Jung, Yil-Sup; Park, Eung-Jun

2008-01-01

The Critical Heat Flux (CHF) on a nuclear fuel is defined by the function of flow channel geometry and flow condition. According to the selection of the explanatory variable, there are three hypotheses to explain CHF at uniformly heated vertical rod (inlet condition hypothesis, exit condition hypothesis, local condition hypothesis). For inlet condition hypothesis, CHF is characterized by function of system pressure, rod diameter, rod length, mass flow and inlet subcooling. For exit condition hypothesis, exit quality substitutes for inlet subcooling. Generally the heated length effect on CHF in exit condition hypothesis is smaller than that of other variables. Heated length is usually excluded in local condition hypothesis to describe the CHF with only local fluid conditions. Most of commercial plants currently use the empirical CHF correlation based on local condition hypothesis. Empirical CHF correlation is developed by the method of fitting the selected sensitive local variables to CHF test data using the multiple non-linear regression. Because this kind of method can not explain physical meaning, it is difficult to reflect the proper effect of complex geometry. So the recent CHF correlation development strategy of nuclear fuel vendor is making the basic CHF correlation which consists of basic flow variables (local fluid conditions) at first, and then the geometrical correction factors are compensated additionally. Because the functional forms of correction factors are determined from the independent test data which represent the corresponding geometry separately, it can be applied to other CHF correlation directly only with minor coefficient modification

Role of humidity and other correction factors in the AAPM TG-21 dosimetry protocol

International Nuclear Information System (INIS)

Rogers, D.W.; Ross, C.K.

1988-01-01

A detailed derivation is presented of the formulas required to determine Ngas and Dmed in the AAPM TG-21 dosimetry protocol. This protocol specifies how to determine the absorbed dose in an electron or photon beam when using exposure or absorbed dose calibrated ion chambers. It is shown that the expression given in TG-21's recent letter of clarification is incorrect. Accounting for humidity correctly increases, by 0.4%, all absorbed dose determinations using an exposure calibrated ion chamber. Taking into account other correction factors in the equation for exposure could also have varying, but significant effects (possibly over 1%). These are the stem scatter correction, the axial nonuniformity correction and the electrode correction for electrodes made of different materials from the wall. Attention is drawn to differences in the definitions of the exposure and absorbed dose calibration factors, Nx and ND, respectively, as supplied by the NBS and the NRCC

Impact of the neutron detector choice on Bell and Glasstone spatial correction factor for subcriticality measurement

Energy Technology Data Exchange (ETDEWEB)

Talamo, Alberto, E-mail: alby@anl.gov [Argonne National Laboratory, 9700S. Cass Avenue, Argonne, IL 60439 (United States); Gohar, Y.; Cao, Y.; Zhong, Z. [Argonne National Laboratory, 9700S. Cass Avenue, Argonne, IL 60439 (United States); Kiyavitskaya, H.; Bournos, V.; Fokov, Y.; Routkovskaya, C. [Joint Institute for Power and Nuclear Research-Sosny, National Academy of Sciences of Belarus, 99 acad. Krasin str., Minsk 220109 (Belarus)

2012-03-11

In subcritical assemblies, the Bell and Glasstone spatial correction factor is used to correct the measured reactivity from different detector positions. In addition to the measuring position, several other parameters affect the correction factor: the detector material, the detector size, and the energy-angle distribution of source neutrons. The effective multiplication factor calculated by computer codes in criticality mode slightly differs from the average value obtained from the measurements in the different experimental channels of the subcritical assembly, which are corrected by the Bell and Glasstone spatial correction factor. Generally, this difference is due to (1) neutron counting errors; (2) geometrical imperfections, which are not simulated in the calculational model, and (3) quantities and distributions of material impurities, which are missing from the material definitions. This work examines these issues and it focuses on the detector choice and the calculation methodologies. The work investigated the YALINA Booster subcritical assembly of Belarus, which has been operated with three different fuel enrichments in the fast zone either: high (90%) and medium (36%), medium (36%), or low (21%) enriched uranium fuel.

Impact of the neutron detector choice on Bell and Glasstone spatial correction factor for subcriticality measurement

International Nuclear Information System (INIS)

Talamo, Alberto; Gohar, Y.; Cao, Y.; Zhong, Z.; Kiyavitskaya, H.; Bournos, V.; Fokov, Y.; Routkovskaya, C.

2012-01-01

In subcritical assemblies, the Bell and Glasstone spatial correction factor is used to correct the measured reactivity from different detector positions. In addition to the measuring position, several other parameters affect the correction factor: the detector material, the detector size, and the energy-angle distribution of source neutrons. The effective multiplication factor calculated by computer codes in criticality mode slightly differs from the average value obtained from the measurements in the different experimental channels of the subcritical assembly, which are corrected by the Bell and Glasstone spatial correction factor. Generally, this difference is due to (1) neutron counting errors; (2) geometrical imperfections, which are not simulated in the calculational model, and (3) quantities and distributions of material impurities, which are missing from the material definitions. This work examines these issues and it focuses on the detector choice and the calculation methodologies. The work investigated the YALINA Booster subcritical assembly of Belarus, which has been operated with three different fuel enrichments in the fast zone either: high (90%) and medium (36%), medium (36%), or low (21%) enriched uranium fuel.

Simulation study of the photon quality correction factors of ionization chambers for FiR 1 epithermal neutron beam

International Nuclear Information System (INIS)

Koivunoro, H.; Uusi-Simola, J.; Savolainen, S.; Kotiluoto, P.; Auterinen, I.; Kosunen, A.

2006-01-01

At FiR 1 BNCT facility in Finland, neutron-insensitive Mg(Ar) ionization chambers are used for photon dose measurements in an epithermal neutron beam. Previously, photon sensitivity factors for the chamber for the measurements in a water phantom in FiR 1 beam have been determined experimentally from measurements in 60 Co gamma and in a 6 MV clinical accelerator photon beams. However, the response of the ionization chamber in a water phantom depends on energy spectrum and angle of the photons and the secondary electrons created inside the phantom and may differ depending on type of the irradiation source (accelerator vs. an epithermal neutron beam). Also, the experimental sensitivity factor does not take into account the possible perturbations in the photon production in phantom caused by the ionization chamber materials. Therefore, it is necessary to determine the photon quality correction factors (k Qγ ) for the Mg(Ar) chamber at the FiR 1 beam through computer simulations. In this study, the k Qγ factors have been determined for Mg(Ar) chamber from Monte Carlo calculations of absorbed photon dose at two depths in a water phantom using MCNP code. The k qγ factors obtained with this method are compared to the sensitivity factors determined with measurements in an accelerator photon beam and to the k Qγ factors published previously. (author)

Determination of the air attenuation correction factor for a free air ionization chamber

International Nuclear Information System (INIS)

Silva, Natalia F.; Cintra, Felipe B.; Castro, Maysa C. de; Caldas, Linda V.E.

2016-01-01

The objective of this work is to present the experimental and simulation results for the air attenuation correction factor for a free air ionization chamber with concentric cylinders of Victoreen, model 481-5. This correction factor was obtained for the standard mammography qualities established in the Instrument Calibration Laboratory (LCI) of IPEN. The values were compared with the results from the German primary standard laboratory Physikalisch- Technische Bundesanstalt (PTB), and maximum differences of 0.40% in relation to the experimental value and 0.31% in relation to the simulated value were obtained. (author)

Evaluation of the uniformity of wide circular reference source and application of correction factors

International Nuclear Information System (INIS)

Silva Junior, I.A.; Xavier, M.; Siqueira, P.T.D.; Sordi, G.A.A.; Potiens, M.P.A.

2017-01-01

In this work the uniformity of wide circular reference sources is evaluated. This kind of reference source is still widely used in Brazil. In previous works wide rectangular reference sources were analyzed and it was shown the importance of the application of correction factors in calibration procedures of radiation monitors. Now a transposition of the methods used formerly is performed, evaluating the uniformities of circular reference sources and calculating the associated correction factors. (author)

Corrective Jaw Surgery

Medline Plus

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Status of the NLO Corrections to the Photon Impact Factor

OpenAIRE

Gieseke, Stefan

2002-01-01

We present the status of the programme of calculating the next-to-leading order corrections to the virtual photon impact factor. In particular, we discuss new results for the transversely polarized photon. We briefly outline the definition of infrared finite terms and the subtraction of the leading logarithmic parts.

Efficiency and attenuation correction factors determination in gamma spectrometric assay of bulk samples using self radiation

International Nuclear Information System (INIS)

Haddad, Kh.

2009-02-01

Gamma spectrometry forms the most important and capable tool for measuring radioactive materials. Determination of the efficiency and attenuation correction factors is the most tedious problem in the gamma spectrometric assay of bulk samples. A new experimental and easy method for these correction factors determination using self radiation was proposed in this work. An experimental study of the correlation between self attenuation correction factor and sample thickness and its practical application was also introduced. The work was performed on NORM and uranyl nitrate bulk sample. The results of proposed methods agreed with those of traditional ones.(author)

Non-linear corrections to the cosmological matter power spectrum and scale-dependent galaxy bias: implications for parameter estimation

International Nuclear Information System (INIS)

Hamann, Jan; Hannestad, Steen; Melchiorri, Alessandro; Wong, Yvonne Y Y

2008-01-01

We explore and compare the performances of two non-linear correction and scale-dependent biasing models for the extraction of cosmological information from galaxy power spectrum data, especially in the context of beyond-ΛCDM (CDM: cold dark matter) cosmologies. The first model is the well known Q model, first applied in the analysis of Two-degree Field Galaxy Redshift Survey data. The second, the P model, is inspired by the halo model, in which non-linear evolution and scale-dependent biasing are encapsulated in a single non-Poisson shot noise term. We find that while the two models perform equally well in providing adequate correction for a range of galaxy clustering data in standard ΛCDM cosmology and in extensions with massive neutrinos, the Q model can give unphysical results in cosmologies containing a subdominant free-streaming dark matter whose temperature depends on the particle mass, e.g., relic thermal axions, unless a suitable prior is imposed on the correction parameter. This last case also exposes the danger of analytic marginalization, a technique sometimes used in the marginalization of nuisance parameters. In contrast, the P model suffers no undesirable effects, and is the recommended non-linear correction model also because of its physical transparency

Non-linear corrections to the cosmological matter power spectrum and scale-dependent galaxy bias: implications for parameter estimation

Science.gov (United States)

Hamann, Jan; Hannestad, Steen; Melchiorri, Alessandro; Wong, Yvonne Y. Y.

2008-07-01

We explore and compare the performances of two non-linear correction and scale-dependent biasing models for the extraction of cosmological information from galaxy power spectrum data, especially in the context of beyond-ΛCDM (CDM: cold dark matter) cosmologies. The first model is the well known Q model, first applied in the analysis of Two-degree Field Galaxy Redshift Survey data. The second, the P model, is inspired by the halo model, in which non-linear evolution and scale-dependent biasing are encapsulated in a single non-Poisson shot noise term. We find that while the two models perform equally well in providing adequate correction for a range of galaxy clustering data in standard ΛCDM cosmology and in extensions with massive neutrinos, the Q model can give unphysical results in cosmologies containing a subdominant free-streaming dark matter whose temperature depends on the particle mass, e.g., relic thermal axions, unless a suitable prior is imposed on the correction parameter. This last case also exposes the danger of analytic marginalization, a technique sometimes used in the marginalization of nuisance parameters. In contrast, the P model suffers no undesirable effects, and is the recommended non-linear correction model also because of its physical transparency.

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

Science.gov (United States)

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).

Fretting fatigue life estimation using fatigue damage gradient correction factor in various contact configurations

Energy Technology Data Exchange (ETDEWEB)

Hwang, Dong Hyeon; Cho, Sung-San [Hongik University, Seoul (Korea, Republic of)

2017-03-15

A fretting fatigue life estimation method that takes into account the stress gradient effect was developed by the authors [Journal of Mechanical Science and Technology, 28 (2014) 2153-2159]. In the developed method, fatigue damage value at the cracking location is corrected with fatigue damage gradient and the corrected value is compared directly with the plain fatigue data for life estimation. In other words, the correction factor is the ratio of plain fatigue damage to fretting fatigue damage at the same life and a function of fatigue damage gradient. Since reliability of the method was verified only for cylinder-on-flat contact configuration in the previous study, the present study extends application of the method to flat-on-flat contact configurations by developing the correction factor for both the contact configuration. Fretting fatigue experiments were conducted to obtain fatigue life data for various fretting pads. Finite element analyses were conducted to evaluate the Smith-Watson-Topper (SWT) fatigue damage parameter in the cracking region. It is revealed that the SWT parameter in fat-on-flat contact configuration decreases exponentially away from the surface as in cylinder-on-flat contact configuration, and thus the SWT gradient at the surface can be evaluated reliably. Moreover, it is found that decrease in the SWT parameter around the cracking location can be expressed by piecewise exponential curves. If the gradient of SWT at the surface is used as a representative value of SWT gradient, it is impossible to establish functional relationship between the SWT gradient and the correction factor for both the contact configurations although it was possible for cylinder-on-flat contact configuration. However, if weighted average of the SWT gradient values obtained from each exponential curve in the piecewise exponential curve is used as a representative value, the correction factor for both the contact configurations becomes a function of the SWT gradient

Seasonal correction factors in radon exposure assessment: are they help or hindrance?

International Nuclear Information System (INIS)

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

2008-01-01

Northern Hemisphere radon levels are generally higher in Winter than in Summer, primarily due to the increased interior/exterior temperature difference during the heating season, which results in greater atmospheric pressure differential and enhanced radon ingress. Following a survey of domestic radon levels in the United Kingdom (UK), the former National Radiological Protection Board (NRPB) established measurement protocols and promulgated nationally-applicable Seasonal Correction Factors (SCF). These factors convert a one-month or three-month radon concentration measurement, commencing in any month of the year, to an annual mean radon concentration. Subsequent study suggests that this approach may not be sufficiently sensitive to local conditions, and a major independent investigation reported seasonal correction factors specific to nine geographic regions, together with a composite set applicable to all regions. Similar geographical variability has been observed in other countries. In a recent evaluation of the applicability of short-term exposures in quantifying long-term domestic radon levels, radon levels in 34 houses were monitored over a 12-month period with 1-week, 1-month and 3-month exposures. Radon concentration variation departed significantly from that expected on the basis of the recommended SCFs, with year-end discontinuities at all exposure durations. Weekly monitoring with electrets was continued in three of these locations for four years. Short-term variations in radon levels were observed, particularly during the shorter exposures, and this dataset has also shown year-on-year variations. Overall, SCFs derived from this dataset are significantly lower than those recommended, but are comparable with other results from the UK and elsewhere, particularly those that recognise geological diversity and are consequently prepared on a regional rather than a national basis. These findings call into question the validity of using nationally

Learning time-dependent noise to reduce logical errors: real time error rate estimation in quantum error correction

Science.gov (United States)

Huo, Ming-Xia; Li, Ying

2017-12-01

Quantum error correction is important to quantum information processing, which allows us to reliably process information encoded in quantum error correction codes. Efficient quantum error correction benefits from the knowledge of error rates. We propose a protocol for monitoring error rates in real time without interrupting the quantum error correction. Any adaptation of the quantum error correction code or its implementation circuit is not required. The protocol can be directly applied to the most advanced quantum error correction techniques, e.g. surface code. A Gaussian processes algorithm is used to estimate and predict error rates based on error correction data in the past. We find that using these estimated error rates, the probability of error correction failures can be significantly reduced by a factor increasing with the code distance.

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

Science.gov (United States)

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 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 EKF method.

Calculations of electron fluence correction factors using the Monte Carlo code PENELOPE

International Nuclear Information System (INIS)

Siegbahn, E A; Nilsson, B; Fernandez-Varea, J M; Andreo, P

2003-01-01

In electron-beam dosimetry, plastic phantom materials may be used instead of water for the determination of absorbed dose to water. A correction factor φ water plastic is then needed for converting the electron fluence in the plastic phantom to the fluence at an equivalent depth in water. The recommended values for this factor given by AAPM TG-25 (1991 Med. Phys. 18 73-109) and the IAEA protocols TRS-381 (1997) and TRS-398 (2000) disagree, in particular at large depths. Calculations of the electron fluence have been done, using the Monte Carlo code PENELOPE, in semi-infinite phantoms of water and common plastic materials (PMMA, clear polystyrene, A-150, polyethylene, Plastic water TM and Solid water TM (WT1)). The simulations have been carried out for monoenergetic electron beams of 6, 10 and 20 MeV, as well as for a realistic clinical beam. The simulated fluence correction factors differ from the values in the AAPM and IAEA recommendations by up to 2%, and are in better agreement with factors obtained by Ding et al (1997 Med. Phys. 24 161-76) using EGS4. Our Monte Carlo calculations are also in good accordance with φ water plastic values measured by using an almost perturbation-free ion chamber. The important interdependence between depth- and fluence-scaling corrections for plastic phantoms is discussed. Discrepancies between the measured and the recommended values of φ water plastic may then be explained considering the different depth-scaling rules used

Design of The High Efficiency Power Factor Correction Circuit for Power Supply

Directory of Open Access Journals (Sweden)

Atiye Hülya OBDAN

2017-12-01

Full Text Available Designing power factor correction circuits for switched power supplies has become important in recent years in terms of efficient use of energy. Power factor correction techniques play a significant role in high power density and energy efficiency. For these purposes, bridgeless PFC topologies and control strategies have been developed alongside basic boost PFC circuits. The power density can be increased using bridgeless structures by means of reducing losses in the circuit. This article examines bridgeless PFC structures and compares their performances in terms of losses and power factor. A semi-bridgeless PFC, which is widely used at high power levels, was analyzed and simulated. The designed circuit simulation using the current mode control method was performed in the PSIM program. A prototype of a 900 W semi-bridgeless PFC circuit was implemented and the results obtained from the circuit are presented

Correction factors for photon spectrometry in nuclear parameters study

International Nuclear Information System (INIS)

Patrao, Karla Cristina de Souza

2004-10-01

The goal of this work was the determination, using metrologic severity, the factors of correction for coincidences XX, Xγ and γγ and the factors of transference of efficiency for use in gamma spectrometry. On this way, it was carried through by determination of nuclear parameters of a nuclide used in medicine diagnostic ( 201 Tl) and the standardization of two environmental samples, of regular and irregular geometry, proceeding from the residual (ashes and slag) from the nuclear industry. The results shows that this adopted methodology is valid, and it allows its application for many different nuclides, including complex decay schema nuclides, using only photons spectrometry techniques on semiconductor detectors. (author)

Gauge dependence and new kind of two-dimensional gravity theory with trivial quantum corrections

International Nuclear Information System (INIS)

Banin, A.T.; Shapiro, I.L.

1993-12-01

We search for the new kinds of classical potentials in two-dimensional induced gravity, which provide the triviality of the one-loop quantum corrections. First of all the gauge dependence of the effective potential is studied. The unique effective potential, introduced by Vilkovisly in 1984 is found to manifest the gauge dependence due to some unusual properties of the theory under consideration. Then we take the gauge of harmonical type, which provides the one-loop finiteness off shell, and then the solution for the required classical potential is found. (author). 35 refs

Determination of velocity correction factors for real-time air velocity monitoring in underground mines.

Science.gov (United States)

Zhou, Lihong; Yuan, Liming; Thomas, Rick; Iannacchione, Anthony

2017-12-01

When there are installations of air velocity sensors in the mining industry for real-time airflow monitoring, a problem exists with how the monitored air velocity at a fixed location corresponds to the average air velocity, which is used to determine the volume flow rate of air in an entry with the cross-sectional area. Correction factors have been practically employed to convert a measured centerline air velocity to the average air velocity. However, studies on the recommended correction factors of the sensor-measured air velocity to the average air velocity at cross sections are still lacking. A comprehensive airflow measurement was made at the Safety Research Coal Mine, Bruceton, PA, using three measuring methods including single-point reading, moving traverse, and fixed-point traverse. The air velocity distribution at each measuring station was analyzed using an air velocity contour map generated with Surfer ® . The correction factors at each measuring station for both the centerline and the sensor location were calculated and are discussed.

A study of coarse mesh collision probability correction factors in slab lattices

International Nuclear Information System (INIS)

Buckler, A.N.

1975-07-01

Calculations of collision probability leakage estimates are performed in one dimensional slab geometry with one neutron group to gain some insight into methods of correction for the coarseness of the mesh H. The chief result is that the correction factor, beta, can be written as CD/H where C → 4 for the diffusion limit. An explicit expression for C is derived in terms of the E 3 function, for a linear flux variation across the slabs. (author)

The non-uniformity correction factor for the cylindrical ionization chambers in dosimetry of an HDR 192Ir brachytherapy source

International Nuclear Information System (INIS)

Majumdar, Bishnu; Patel, Narayan Prasad; Vijayan, V.

2006-01-01

The aim of this study is to derive the non-uniformity correction factor for the two therapy ionization chambers for the dose measurement near the brachytherapy source. The two ionization chambers of 0.6 cc and 0.1 cc volume were used. The measurement in air was performed for distances between 0.8 cm and 20 cm from the source in specially designed measurement jig. The non-uniformity correction factors were derived from the measured values. The experimentally derived factors were compared with the theoretically calculated non-uniformity correction factors and a close agreement was found between these two studies. The experimentally derived non-uniformity correction factor supports the anisotropic theory. (author)

Regression dilution bias: tools for correction methods and sample size calculation.

Science.gov (United States)

Berglund, Lars

2012-08-01

Random errors in measurement of a risk factor will introduce downward bias of an estimated association to a disease or a disease marker. This phenomenon is called regression dilution bias. A bias correction may be made with data from a validity study or a reliability study. In this article we give a non-technical description of designs of reliability studies with emphasis on selection of individuals for a repeated measurement, assumptions of measurement error models, and correction methods for the slope in a simple linear regression model where the dependent variable is a continuous variable. Also, we describe situations where correction for regression dilution bias is not appropriate. The methods are illustrated with the association between insulin sensitivity measured with the euglycaemic insulin clamp technique and fasting insulin, where measurement of the latter variable carries noticeable random error. We provide software tools for estimation of a corrected slope in a simple linear regression model assuming data for a continuous dependent variable and a continuous risk factor from a main study and an additional measurement of the risk factor in a reliability study. Also, we supply programs for estimation of the number of individuals needed in the reliability study and for choice of its design. Our conclusion is that correction for regression dilution bias is seldom applied in epidemiological studies. This may cause important effects of risk factors with large measurement errors to be neglected.

Self-attenuation correction factors for bioindicators measured by γ spectrometry for energies <100keV

International Nuclear Information System (INIS)

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 γ 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.

Novel scatter compensation with energy and spatial dependent corrections in positron emission tomography

International Nuclear Information System (INIS)

Guerin, Bastien

2010-01-01

We developed and validated a fast Monte Carlo simulation of PET acquisitions based on the SimSET program modeling accurately the propagation of gamma photons in the patient as well as the block-based PET detector. Comparison of our simulation with another well validated code, GATE, and measurements on two GE Discovery ST PET scanners showed that it models accurately energy spectra (errors smaller than 4.6%), the spatial resolution of block-based PET scanners (6.1%), scatter fraction (3.5%), sensitivity (2.3%) and count rates (12.7%). Next, we developed a novel scatter correction incorporating the energy and position of photons detected in list-mode. Our approach is based on the reformulation of the list-mode likelihood function containing the energy distribution of detected coincidences in addition to their spatial distribution, yielding an EM reconstruction algorithm containing spatial and energy dependent correction terms. We also proposed using the energy in addition to the position of gamma photons in the normalization of the scatter sinogram. Finally, we developed a method for estimating primary and scatter photons energy spectra from total spectra detected in different sectors of the PET scanner. We evaluated the accuracy and precision of our new spatio-spectral scatter correction and that of the standard spatial correction using realistic Monte Carlo simulations. These results showed that incorporating the energy in the scatter correction reduces bias in the estimation of the absolute activity level by ∼ 60% in the cold regions of the largest patients and yields quantification errors less than 13% in all regions. (author)

Experimental determination of the weighting factor for the energy window subtraction-based downscatter correction for I-123 in brain SPECT studies

DEFF Research Database (Denmark)

de Nijs, Robin; Holm, Søren; Thomsen, Gerda

2010-01-01

Correction for downscatter in I-123 SPECT can be performed by the subtraction of a secondary energy window from the main window, as in the triple-energy window method. This is potentially noise sensitive. For studies with limited amount of counts (e.g. dynamic studies), a broad subtraction window...... were investigated in this study. Energy windows with a width of 32 keV were centered at 159 keV and 200 keV. The weighting factor was measured both with an I-123 point source and in a dopamine transporter brain SPECT study in 10 human subjects (5 healthy subjects and 5 patients) by minimizing...... the background outside the head. Weighting factors ranged from 1.11 to 1.13 for the point source and from 1.16 to 1.18 for human subjects. Point source measurements revealed no position dependence. After correction, the measured specific binding ratio (image contrast) increased significantly for healthy subjects...

Integrals of random fields treated by the model correction factor method

DEFF Research Database (Denmark)

Franchin, P.; Ditlevsen, Ove Dalager; Kiureghian, Armen Der

2002-01-01

The model correction factor method (MCFM) is used in conjunction with the first-order reliability method (FORM) to solve structural reliability problems involving integrals of non-Gaussian random fields. The approach replaces the limit-state function with an idealized one, in which the integrals ...

A transient, Hex-Z nodal code corrected by discontinuity factors

International Nuclear Information System (INIS)

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

1993-01-01

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

Time dependent deadtime and pile-up corrections for gamma-ray spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Roscoe, B A; Furr, A K [Virginia Polytechnic Inst. and State Univ., Blacksburg (USA)

1977-01-15

The losses of pulses in gamma spectroscopy due to the analog-to-digital (ADC) conversion process and due to pulse pile-up is a major problem in quantitative gamma ray spectroscopy. It is especially serious if the count rate varies significantly during the counting interval and if the nuclear events of interest are associated with an isotope with a half-life shorter than or comparable to the counting interval as is often the case for isotopes with half-lives of the order of 10 min or less. The count rates at which dead time losses become a problem depend upon the available equipment but, in the present work, the problem became acute at count rates in excess of 25000 cps. A technique developed at VPI and SU is discussed in the present work which very satisfactorily corrects for both ADC and pile-up losses and is dependent upon the half-life of the decaying radioisotope.

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

International Nuclear Information System (INIS)

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

Determination of correction and conversion factor of exposure rate generated Gamma spectrometer GR-320 to Victoreen data

International Nuclear Information System (INIS)

Supardjo-AS; Mappa, Djody-Rachim; Nasrun-Syamsul; Syamsul-Hadi

2000-01-01

Exposure rate data of Muria Peninsula were generated from Victoreen-491 measurement and calculation of radioelement content in soil which were measured by Exploranium GR-320, using IAEA formula. However those data are not be comparable so the exposure rate calculated from Gamma Spectrometer data necessarily to be corrected. The correction factor was determinate by measuring the exposure rate of at the NMDC's back yard selected location using Victoreen-491 and Gamma Spectrometer Exploranium GR-320 . Correction factor was created by comparing mean exposure rate data that calculated from 30 data measured by Gamma Spectrometer instrument and to those Victoreen's exposure rate. Conversion factor was gained from comparing of total count data of Gamma Spectrometer Exploranium GR-320 to Victoreen's exposure rate data. The correction factor of Exploranium GR-320's exposure rate is 0.34 μR/hours, and the conversion factor of total count is 0.0092 μR/hours per c/m. Deviation Victoreen 491 = 4.7 % and Gamma Spectrometer Exploranium GR-320 8.6 %

Validity and factor structure of the bodybuilding dependence scale.

Science.gov (United States)

Smith, D; Hale, B

2004-04-01

To investigate the factor structure, validity, and reliability of the bodybuilding dependence scale and to investigate differences in bodybuilding dependence between men and women and competitive and non-competitive bodybuilders. Seventy two male competitive bodybuilders, 63 female competitive bodybuilders, 87 male non-competitive bodybuilders, and 63 non-competitive female bodybuilders completed the bodybuilding dependence scale (BDS), the exercise dependence questionnaire (EDQ), and the muscle dysmorphia inventory (MDI). Confirmatory factor analysis of the BDS supported a three factor model of bodybuilding dependence, consisting of social dependence, training dependence, and mastery dependence (Q = 3.16, CFI = 0.98, SRMR = 0.04). Internal reliability of all three subscales was high (Cronbach's alpha = 0.92, 0.92, and 0.93 respectively). Significant (pbodybuilders scored significantly (pbodybuilders. However, there were no significant sex differences on any of the BDS subscales (p>0.05). The three factor BDS appears to be a reliable and valid measure of bodybuilding dependence. Symptoms of bodybuilding dependence are more prevalent in competitive bodybuilders than non-competitive ones, but there are no significant sex differences in bodybuilding dependence.

Applicability of perturbative QCD and NLO power corrections for the pion form factor

International Nuclear Information System (INIS)

Yeh Tsungwen

2002-01-01

As is well recognized, the asymptotic of the perturbative QCD prediction for the pion form factor is much smaller than the upper end of the data. We investigate this problem. We first evaluate the next-to-leading-order (NLO) power correction for the pion form factor. The corrected form factor contains nonperturbative parameters which are determined from a χ 2 fit to the data. Interpreting these parameters leads to the fact that the involved strong interaction coupling constant should be identified as an effective coupling constant under a nonperturbative QCD vacuum. If the scale associated with the effective coupling constant is identified as 2 Q 2 , then Q 2 , the momentum transfer square for the pion form factor to be measured, can have a value about 1 GeV 2 , and , the averaged momentum fraction variable, can locate around 0.5. This circumstance is consistent with the asymptotic model for the pion wave function

Sci—Fri AM: Mountain — 01: Validation of a new formulism and the related correction factors on output factor determination for small photon fields

Energy Technology Data Exchange (ETDEWEB)

Wang, Yizhen; Younge, Kelly; Nielsen, Michelle; Mutanga, Theodore [Peel Regional Cancer Center, Trillium Health Partners, Mississauga, ON (Canada); Cui, Congwu [Peel Regional Cancer Center, Trillium Health Partners, Mississauga, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Das, Indra J. [Radiation Oncology Dept., Indiana University- School of Medicine, Indianapolis, IN (United States)

2014-08-15

Small field dosimetry measurements including output factors are difficult due to lack of charged-particle equilibrium, occlusion of the radiation source, the finite size of detectors, and non-water equivalence of detector components. With available detectors significant variations could be measured that will lead to incorrect delivered dose to patients. IAEA/AAPM have provided a framework and formulation to correct the detector response in small photon fields. Monte Carlo derived correction factors for some commonly used small field detectors are now available, however validation has not been performed prior to this study. An Exradin A16 chamber, EDGE detector and SFD detector were used to perform the output factor measurement for a series of conical fields (5–30mm) on a Varian iX linear accelerator. Discrepancies up to 20%, 10% and 6% were observed for 5, 7.5 and 10 mm cones between the initial output factors measured by the EDGE detector and the A16 ion chamber, while the discrepancies for the conical fields larger than 10 mm were less than 4%. After the application of the correction, the output factors agree well with each other to within 1%. Caution is needed when determining the output factors for small photon fields, especially for fields 10 mm in diameter or smaller. More than one type of detector should be used, each with proper corrections applied to the measurement results. It is concluded that with the application of correction factors to appropriately chosen detectors, output can be measured accurately for small fields.

An improved correlated sampling method for calculating correction factor of detector

International Nuclear Information System (INIS)

Wu Zhen; Li Junli; Cheng Jianping

2006-01-01

In the case of a small size detector lying inside a bulk of medium, there are two problems in the correction factors calculation of the detectors. One is that the detector is too small for the particles to arrive at and collide in; the other is that the ratio of two quantities is not accurate enough. The method discussed in this paper, which combines correlated sampling with modified particle collision auto-importance sampling, and has been realized on the MCNP-4C platform, can solve these two problems. Besides, other 3 variance reduction techniques are also combined with correlated sampling respectively to calculate a simple calculating model of the correction factors of detectors. The results prove that, although all the variance reduction techniques combined with correlated sampling can improve the calculating efficiency, the method combining the modified particle collision auto-importance sampling with the correlated sampling is the most efficient one. (authors)

Next to Leading Order QCD Corrections to Polarized $\\Lambda$ Production in DIS

CERN Document Server

de Florian, D

1997-01-01

We calculate next to leading order QCD corrections to semi-inclusive polarized deep inelastic scattering and $e^+e^-$ annihilation cross sections for processes where the polarization of the identified final-state hadron can also be determined. Using dimensional regularization and the HVBM prescription for the $\\gamma_5$ matrix, we compute corrections for different spin-dependent observables, both in the $\\overline{MS}$ and $\\overline{MS_p}$ factorization schemes, and analyse their structure. In addition to the well known corrections to polarized parton distributions, we also present those for final-state polarized fracture functions and polarized fragmentation functions, in a consistent factorization scheme.

Long-term correction of canine hemophilia B by gene transfer of blood coagulation factor IX mediated by adeno-associated viral vector.

Science.gov (United States)

Herzog, R W; Yang, E Y; Couto, L B; Hagstrom, J N; Elwell, D; Fields, P A; Burton, M; Bellinger, D A; Read, M S; Brinkhous, K M; Podsakoff, G M; Nichols, T C; Kurtzman, G J; High, K A

1999-01-01

Hemophilia B is a severe X-linked bleeding diathesis caused by the absence of functional blood coagulation factor IX, and is an excellent candidate for treatment of a genetic disease by gene therapy. Using an adeno-associated viral vector, we demonstrate sustained expression (>17 months) of factor IX in a large-animal model at levels that would have a therapeutic effect in humans (up to 70 ng/ml, adequate to achieve phenotypic correction, in an animal injected with 8.5x10(12) vector particles/kg). The five hemophilia B dogs treated showed stable, vector dose-dependent partial correction of the whole blood clotting time and, at higher doses, of the activated partial thromboplastin time. In contrast to other viral gene delivery systems, this minimally invasive procedure, consisting of a series of percutaneous intramuscular injections at a single timepoint, was not associated with local or systemic toxicity. Efficient gene transfer to muscle was shown by immunofluorescence staining and DNA analysis of biopsied tissue. Immune responses against factor IX were either absent or transient. These data provide strong support for the feasibility of the approach for therapy of human subjects.

How important is self-consistency for the dDsC density dependent dispersion correction?

Energy Technology Data Exchange (ETDEWEB)

Brémond, Éric; Corminboeuf, Clémence, E-mail: clemence.corminboeuf@epfl.ch [Laboratory for Computational Molecular Design, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Golubev, Nikolay [Laboratory for Computational Molecular Design, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Steinmann, Stephan N., E-mail: sns25@duke.edu [Laboratory for Computational Molecular Design, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States)

2014-05-14

The treatment of dispersion interactions is ubiquitous but computationally demanding for seamless ab initio approaches. A highly popular and simple remedy consists in correcting for the missing interactions a posteriori by adding an attractive energy term summed over all atom pairs to standard density functional approximations. These corrections were originally based on atom pairwise parameters and, hence, had a strong touch of empiricism. To overcome such limitations, we recently proposed a robust system-dependent dispersion correction, dDsC, that is computed from the electron density and that provides a balanced description of both weak inter- and intramolecular interactions. From the theoretical point of view and for the sake of increasing reliability, we here verify if the self-consistent implementation of dDsC impacts ground-state properties such as interaction energies, electron density, dipole moments, geometries, and harmonic frequencies. In addition, we investigate the suitability of the a posteriori scheme for molecular dynamics simulations, for which the analysis of the energy conservation constitutes a challenging tests. Our study demonstrates that the post-SCF approach in an excellent approximation.

Conduction Losses and Common Mode EMI Analysis on Bridgeless Power Factor Correction

DEFF Research Database (Denmark)

Li, Qingnan; Andersen, Michael Andreas E.; Thomsen, Ole Cornelius

2009-01-01

In this paper, a review of Bridgeless Boost power factor correction (PFC) converters is presented at first. Performance comparison on conduction losses and common mode electromagnetic interference (EMI) are analyzed between conventional Boost PFC converter and members of Bridgeless PFC family...

Socio-emotional factors in alcohol dependence.

Science.gov (United States)

Tikka, Deyashini Lahiri; Ram, Daya; Dubey, Indu; Tikka, Sai Krishna

2014-04-01

Alcohol-dependent patients are traditionally believed to have insecure attachment styles, higher anger expression, and lower self-esteem. There is a need to study them together. To understand the relationships amongst various of the socio-emotional factors. Forty male patients with Alcohol dependence syndrome and 40 matched healthy controls (General Health Questionnaire-12 score Relationship Scale Questionnaire), anger domains (on State Trait Anger Expression Inventory), and self-esteem (on Rosenberg Self-esteem Scale). Comparison using independent samples t test and chi square test; correlation using Pearson's correlation coefficient. Patients had significantly higher anger expression, 'anger in' and 'anger out,' and lower self-esteem than healthy controls. Severity of alcohol dependence had significant correlation with 'anger out,' and self-esteem had significant negative correlation with anger expression. The present study suggests that the socio-emotional factors studied are developmentally linked to each other.

An efficient dose-compensation method for proximity effect correction

International Nuclear Information System (INIS)

Wang Ying; Han Weihua; Yang Xiang; Zhang Yang; Yang Fuhua; Zhang Renping

2010-01-01

A novel simple dose-compensation method is developed for proximity effect correction in electron-beam lithography. The sizes of exposed patterns depend on dose factors while other exposure parameters (including accelerate voltage, resist thickness, exposing step size, substrate material, and so on) remain constant. This method is based on two reasonable assumptions in the evaluation of the compensated dose factor: one is that the relation between dose factors and circle-diameters is linear in the range under consideration; the other is that the compensated dose factor is only affected by the nearest neighbors for simplicity. Four-layer-hexagon photonic crystal structures were fabricated as test patterns to demonstrate this method. Compared to the uncorrected structures, the homogeneity of the corrected hole-size in photonic crystal structures was clearly improved. (semiconductor technology)

Low Capacitive Inductors for Fast Switching Devices in Active Power Factor Correction Applications

DEFF Research Database (Denmark)

Hernandez Botella, Juan Carlos; Petersen, Lars Press; Andersen, Michael A. E.

2014-01-01

This paper examines different winding strategies for reduced capacitance inductors in active power factor correction circuits (PFC). The effect of the parasitic capacitance is analyzed from an electro magnetic compatibility (EMI) and efficiency point of views. The purpose of this work is to inves......This paper examines different winding strategies for reduced capacitance inductors in active power factor correction circuits (PFC). The effect of the parasitic capacitance is analyzed from an electro magnetic compatibility (EMI) and efficiency point of views. The purpose of this work...... is to investigate different winding approaches and identify suitable solutions for high switching frequency/high speed transition PFC designs. A low parasitic capacitance PCB based inductor design is proposed to address the challenges imposed by high switching frequency PFC Boost converters....

Analysis of the principal factors that intervene in the quantification of planar images of uniform distributions of 99mTc by the conjugate view method with background correction by simple subtraction

International Nuclear Information System (INIS)

Mora Araya, Luis Diego

2013-01-01

The activity of uniform distributions of 99m Tc was quantified by the conjugate view method. The necessary factors of calibration and transmission were calculated to realize the quantification. The dependence of the estimated number of accounts within the source region and variability of the value of the transmission factor were determined, according to the size established for the region of interest, keeping constant its geometry. The images of all acquisitions were corrected by environmental background radiation and radiation dispersed, by the dual energy window method (DEW). The impact of corrections in the image were checked, both qualitatively and quantitative. The acquisition to obtain the calibration factor was realized with the same configuration and the same conditions that were used to realize the acquisition for quantification; in which, the same volume and the same geometry were used to contain the distribution of the activity of 99m Tc. The volume and geometry of the same medium attenuator have obtained a calibration factor exactly in the same circumstances in which have quantified. The behavior of the estimation of the calibration factor of the gamma camera was analyzed, according to the decay corrections of the activity and the attenuation that are applied. The dependence of the calibration factors and transmission were analyzed, according to the region of interest used in the corresponding images to estimate their values. The behavior of the estimation of the activity was determined, according to all possible combinations of the factors studied that have intervened in the quantification algorithm of conjugate view, namely, the size of the region of interest corresponding to the source region, the transmission factor , the calibration factor and background correction by simple subtraction. The results obtained of the estimates of the activity were compared. A tendency is established, indicating which have been combinations of the studied factors that

Gamma camera correction system and method for using the same

International Nuclear Information System (INIS)

Inbar, D.; Gafni, G.; Grimberg, E.; Bialick, K.; Koren, J.

1986-01-01

A gamma camera is described which consists of: (a) a detector head that includes photodetectors for producing output signals in response to radiation stimuli which are emitted by a radiation field and which interact with the detector head and produce an event; (b) signal processing circuitry responsive to the output signals of the photodetectors for producing a sum signal that is a measure of the total energy of the event; (c) an energy discriminator having a relatively wide window for comparison with the sum signal; (d) the signal processing circuitry including coordinate computation circuitry for operating on the output signals, and calculating an X,Y coordinate of an event when the sum signal lies within the window of the energy discriminator; (e) an energy correction table containing spatially dependent energy windows for producing a validation signal if the total energy of an event lies within the window associated with the X,Y coordinates of the event; (f) the signal processing circuitry including a dislocation correction table containing spatially dependent correction factors for converting the X,Y coordinates of an event to relocated coordinates in accordance with correction factors determined by the X,Y coordinates; (g) a digital memory for storing a map of the radiation field; and (h) means for recording an event at its relocated coordinates in the memory if the energy correction table produces a validation signal

Corrections in clinical Magnetic Resonance Spectroscopy and SPECT

DEFF Research Database (Denmark)

de Nijs, Robin

infants. In Iodine-123 SPECT the problem of downscatter was addressed. This thesis is based on two papers. Paper I deals with the problem of motion in Single Voxel Spectroscopy. Two novel methods for the identification of outliers in the set of repeated measurements were implemented and compared...... a detrimental effect of the extra-uterine environment on brain development. Paper II describes a method to correct for downscatter in low count Iodine-123 SPECT with a broad energy window above the normal imaging window. Both spatial dependency and weight factors were measured. As expected, the implicitly...... be performed by the subtraction of an energy window, a method was developed to perform scatter and downscatter correction simultaneously. A phantom study has been performed, where the in paper II described downscatter correction was extended with scatter correction. This new combined correction was compared...

Socio-emotional factors in alcohol dependence

OpenAIRE

Deyashini Lahiri Tikka; Daya Ram; Indu Dubey; Sai Krishna Tikka

2014-01-01

Background: Alcohol-dependent patients are traditionally believed to have insecure attachment styles, higher anger expression, and lower self-esteem. There is a need to study them together. Aim: To understand the relationships amongst various of the socio-emotional factors. Materials and Methods: Forty male patients with Alcohol dependence syndrome and 40 matched healthy controls (General Health Questionnaire-12 score

Correction factors for {gamma}-ray relative intensities in the {sup 66}Ga radioisotope

Energy Technology Data Exchange (ETDEWEB)

Schmid, G.J. [Duke Univ., Durham, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Chasteler, R.M. [Duke Univ., Durham, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Laymon, C.M. [Duke Univ., Durham, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Weller, H.R. [Duke Univ., Durham, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Moore, E.F. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Bybee, C.R. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Drake, J.M. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Tilley, D.R. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Vavrina, G. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Wallace, P.M. [Triangle Universities Nuclear Lab., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States)

1996-09-16

We present here strong evidence that recently published values for the relative intensities of {gamma}-ray lines in the {sup 66}Ga({beta}{sup +}+EC){sup 66}Zn decay are incorrect at the higher energies ({proportional_to}30% too low at 4.8 MeV). In particular, we find that our current results are consistent with a set of correction factors which were first suggested 20 years ago, but have gone largely ignored until now. Our validation of these little known correction factors will have bearing on experiments which use the {sup 66}Ga radioisotope to extrapolate absolute detector efficiencies to higher energies. In particular, we discuss the conclusions of a recent D(p, {gamma}){sup 3}He experiment which will be strongly affected by our current results. The astrophysical S-factor data derived from this D(p, {gamma}){sup 3}He experiment are now seen to be systematically too low by {proportional_to}30%. (orig.).

Experimental validation of gallium production and isotope-dependent positron range correction in PET

Energy Technology Data Exchange (ETDEWEB)

Fraile, L.M., E-mail: lmfraile@ucm.es [Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Herraiz, J.L.; Udías, J.M.; Cal-González, J.; Corzo, P.M.G.; España, S.; Herranz, E.; Pérez-Liva, M.; Picado, E.; Vicente, E. [Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Muñoz-Martín, A. [Centro de Microanálisis de Materiales, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Vaquero, J.J. [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid (Spain)

2016-04-01

Positron range (PR) is one of the important factors that limit the spatial resolution of positron emission tomography (PET) preclinical images. Its blurring effect can be corrected to a large extent if the appropriate method is used during the image reconstruction. Nevertheless, this correction requires an accurate modelling of the PR for the particular radionuclide and materials in the sample under study. In this work we investigate PET imaging with {sup 68}Ga and {sup 66}Ga radioisotopes, which have a large PR and are being used in many preclinical and clinical PET studies. We produced a {sup 68}Ga and {sup 66}Ga phantom on a natural zinc target through (p,n) reactions using the 9-MeV proton beam delivered by the 5-MV CMAM tandetron accelerator. The phantom was imaged in an ARGUS small animal PET/CT scanner and reconstructed with a fully 3D iterative algorithm, with and without PR corrections. The reconstructed images at different time frames show significant improvement in spatial resolution when the appropriate PR is applied for each frame, by taking into account the relative amount of each isotope in the sample. With these results we validate our previously proposed PR correction method for isotopes with large PR. Additionally, we explore the feasibility of PET imaging with {sup 68}Ga and {sup 66}Ga radioisotopes in proton therapy.

Chromaticity correction for the SSC collider rings

International Nuclear Information System (INIS)

Sen, T.; Nosochkov, Y.; Pilat, F.; Stiening, R.; Ritson, D.M.

1993-01-01

The authors address the issue of correcting higher order chromaticities of the collider with one or more low β insertions. The chromaticity contributed by the interaction regions (IRs) depends crucially on the maximum value of β in the two IRs in a cluster, the phase advance between adjacent interaction points (IPs), and the choice of global tune. They propose a correction scheme in which the linear chromaticity is corrected by a global distribution of sextupoles and the second order chromaticity of each IR is corrected by a more local set of sextupoles. Compared to the case where only the linear chromaticity is corrected, this configuration increases the momentum aperture more than three times and also reduces the β beat by this factor. With this scheme, the tune can be chosen to satisfy other constraints and the two IRs in a cluster can be operated independently at different luminosities without affecting the chromatic properties of the ring

Chromaticity correction for the SSC Collider Rings

International Nuclear Information System (INIS)

Sen, T.; Nosochkov, Y.; Pilat, F.; Stiening, R.; Ritson, D.M.

1993-05-01

We address the issue of correcting higher order chromaticities of the collider with one or more low β insertions. The chromaticity contributed by the interaction regions (IRS) depends crucially on the maximum value of β in the two IRs in a cluster, the phase advance between adjacent interaction points (IPs), and the choice of global tune. We propose a correction scheme in which the linear chromaticity is corrected by a global distribution of sextupoles and the second order chromaticity of each IR is corrected by a more local set of sextupoles. Compared to the case where only the linear chromaticity is corrected, this configuration increases the momentum aperture more than three times and also reduces the β beat by this factor. With this scheme, the tune can be chosen to satisfy other constraints and the two IRs in a cluster can be operated independently at different luminosities without affecting the chromatic properties of the ring

Hydrophone area-averaging correction factors in nonlinearly generated ultrasonic beams

International Nuclear Information System (INIS)

Cooling, M P; Humphrey, V F; Wilkens, V

2011-01-01

The nonlinear propagation of an ultrasonic wave can be used to produce a wavefield rich in higher frequency components that is ideally suited to the calibration, or inter-calibration, of hydrophones. These techniques usually use a tone-burst signal, limiting the measurements to harmonics of the fundamental calibration frequency. Alternatively, using a short pulse enables calibration at a continuous spectrum of frequencies. Such a technique is used at PTB in conjunction with an optical measurement technique to calibrate devices. Experimental findings indicate that the area-averaging correction factor for a hydrophone in such a field demonstrates a complex behaviour, most notably varying periodically between frequencies that are harmonics of the centre frequency of the original pulse and frequencies that lie midway between these harmonics. The beam characteristics of such nonlinearly generated fields have been investigated using a finite difference solution to the nonlinear Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation for a focused field. The simulation results are used to calculate the hydrophone area-averaging correction factors for 0.2 mm and 0.5 mm devices. The results clearly demonstrate a number of significant features observed in the experimental investigations, including the variation with frequency, drive level and hydrophone element size. An explanation for these effects is also proposed.

Hydrophone area-averaging correction factors in nonlinearly generated ultrasonic beams

Science.gov (United States)

Cooling, M. P.; Humphrey, V. F.; Wilkens, V.

2011-02-01

The nonlinear propagation of an ultrasonic wave can be used to produce a wavefield rich in higher frequency components that is ideally suited to the calibration, or inter-calibration, of hydrophones. These techniques usually use a tone-burst signal, limiting the measurements to harmonics of the fundamental calibration frequency. Alternatively, using a short pulse enables calibration at a continuous spectrum of frequencies. Such a technique is used at PTB in conjunction with an optical measurement technique to calibrate devices. Experimental findings indicate that the area-averaging correction factor for a hydrophone in such a field demonstrates a complex behaviour, most notably varying periodically between frequencies that are harmonics of the centre frequency of the original pulse and frequencies that lie midway between these harmonics. The beam characteristics of such nonlinearly generated fields have been investigated using a finite difference solution to the nonlinear Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation for a focused field. The simulation results are used to calculate the hydrophone area-averaging correction factors for 0.2 mm and 0.5 mm devices. The results clearly demonstrate a number of significant features observed in the experimental investigations, including the variation with frequency, drive level and hydrophone element size. An explanation for these effects is also proposed.

75 FR 72739 - Compliance Testing Procedures: Correction Factor for Room Air Conditioners

Science.gov (United States)

2010-11-26

...: Correction Factor for Room Air Conditioners AGENCY: Office of the General Counsel, Department of Energy (DOE... air conditioners. The petition seeks temporary enforcement forbearance, or in the alternative, a... procedures for room air conditioners. Public comment is requested on whether DOE should grant the petition...

Continuous quantum error correction for non-Markovian decoherence

International Nuclear Information System (INIS)

Oreshkov, Ognyan; Brun, Todd A.

2007-01-01

We study the effect of continuous quantum error correction in the case where each qubit in a codeword is subject to a general Hamiltonian interaction with an independent bath. We first consider the scheme in the case of a trivial single-qubit code, which provides useful insights into the workings of continuous error correction and the difference between Markovian and non-Markovian decoherence. We then study the model of a bit-flip code with each qubit coupled to an independent bath qubit and subject to continuous correction, and find its solution. We show that for sufficiently large error-correction rates, the encoded state approximately follows an evolution of the type of a single decohering qubit, but with an effectively decreased coupling constant. The factor by which the coupling constant is decreased scales quadratically with the error-correction rate. This is compared to the case of Markovian noise, where the decoherence rate is effectively decreased by a factor which scales only linearly with the rate of error correction. The quadratic enhancement depends on the existence of a Zeno regime in the Hamiltonian evolution which is absent in purely Markovian dynamics. We analyze the range of validity of this result and identify two relevant time scales. Finally, we extend the result to more general codes and argue that the performance of continuous error correction will exhibit the same qualitative characteristics

Systematic uncertainties in the Monte Carlo calculation of ion chamber replacement correction factors

Energy Technology Data Exchange (ETDEWEB)

Wang, L. L. W.; La Russa, D. J.; Rogers, D. W. O. [Ottawa Carleton Institute of Physics, Carleton University, Campus Ottawa, Ottawa, Ontario KIS 5B6 (Canada)

2009-05-15

In a previous study [Med. Phys. 35, 1747-1755 (2008)], the authors proposed two direct methods of calculating the replacement correction factors (P{sub repl} or p{sub cav}p{sub dis}) for ion chambers by Monte Carlo calculation. By ''direct'' we meant the stopping-power ratio evaluation is not necessary. The two methods were named as the high-density air (HDA) and low-density water (LDW) methods. Although the accuracy of these methods was briefly discussed, it turns out that the assumption made regarding the dose in an HDA slab as a function of slab thickness is not correct. This issue is reinvestigated in the current study, and the accuracy of the LDW method applied to ion chambers in a {sup 60}Co photon beam is also studied. It is found that the two direct methods are in fact not completely independent of the stopping-power ratio of the two materials involved. There is an implicit dependence of the calculated P{sub repl} values upon the stopping-power ratio evaluation through the choice of an appropriate energy cutoff {Delta}, which characterizes a cavity size in the Spencer-Attix cavity theory. Since the {Delta} value is not accurately defined in the theory, this dependence on the stopping-power ratio results in a systematic uncertainty on the calculated P{sub repl} values. For phantom materials of similar effective atomic number to air, such as water and graphite, this systematic uncertainty is at most 0.2% for most commonly used chambers for either electron or photon beams. This uncertainty level is good enough for current ion chamber dosimetry, and the merits of the two direct methods of calculating P{sub repl} values are maintained, i.e., there is no need to do a separate stopping-power ratio calculation. For high-Z materials, the inherent uncertainty would make it practically impossible to calculate reliable P{sub repl} values using the two direct methods.

High efficiency three-phase power factor correction rectifier using SiC switches

DEFF Research Database (Denmark)

Kouchaki, Alireza; Nymand, Morten

2017-01-01

This paper presents designing procedure of a high efficiency 5 kW silicon-carbide (SiC) based threephase power factor correction (PFC). SiC switches present low capacitive switching loss compared to the alternative Si switches. Therefore, the switching frequency can be increased and hence the siz...

Correction Factor Analysis Of Foil Activation And The Effect Of Neglecting The Correction On Neutron Flux And Spectrum Measurement; ANALISIS FAKTOR KOREKSI KEPING AKTIVASI DAN PENGARUH PENGABAIANNYA PADA PENGUKURAN FLUKS DAN SPEKTRUM NEUTRON

Energy Technology Data Exchange (ETDEWEB)

Radiyanti, Ita Budi; Hamzah, Amir; Pinem, Surian [Multipurpose Reactor Centre Indonesia, Serpong, (Indonesia)

1996-04-15

Foil activation method is commonly used in flux and neutron spectrum measurement in nuclear reactor and other research. The effect of the thickness, type of foil material and neutron spectrum shape on the self shielding correction and activities correction on the edges of the foil have been analyzed. Also the effect of neglecting those correction factors on neutron flux and spectrum measurement were analyzed. The calculation of the correction factor has been done by using the program which had been verified for several foils. The foils used are Au, In. Cu, Co and Dy of 0.00254 cm -0.127 cm thickness and 1.27 cm diameter. The result showed that the correction factor foils were not similar due to the variation of activation cross section and neutron spectrum shape. For the neutron spectrum in RS-2 multi purpose reactor GAS using foils of 0.00254 cm thick. The effect of neglecting correction factor on thermal flux measurement for Au, In, Co and Cu were less than -6%, for Dy was about -25%. On epithermal flux measurement for Au and In were about -60%, Co and Dy was -12% and -6%, for Cu less than -2%. The effect of neglecting correction factor on spectrum measurement was the change on the neutron flux density values along neutron energy region.

SU-F-I-13: Correction Factor Computations for the NIST Ritz Free Air Chamber for Medium-Energy X Rays

International Nuclear Information System (INIS)

Bergstrom, P

2016-01-01

Purpose: The National Institute of Standards and Technology (NIST) uses 3 free-air chambers to establish primary standards for radiation dosimetry at x-ray energies. For medium-energy × rays, the Ritz free-air chamber is the main measurement device. In order to convert the charge or current collected by the chamber to the radiation quantities air kerma or air kerma rate, a number of correction factors specific to the chamber must be applied. Methods: We used the Monte Carlo codes EGSnrc and PENELOPE. Results: Among these correction factors are the diaphragm correction (which accounts for interactions of photons from the x-ray source in the beam-defining diaphragm of the chamber), the scatter correction (which accounts for the effects of photons scattered out of the primary beam), the electron-loss correction (which accounts for electrons that only partially expend their energy in the collection region), the fluorescence correction (which accounts for ionization due to reabsorption ffluorescence photons and the bremsstrahlung correction (which accounts for the reabsorption of bremsstrahlung photons). We have computed monoenergetic corrections for the NIST Ritz chamber for the 1 cm, 3 cm and 7 cm collection plates. Conclusion: We find good agreement with other’s results for the 7 cm plate. The data used to obtain these correction factors will be used to establish air kerma and it’s uncertainty in the standard NIST x-ray beams.

SU-F-I-13: Correction Factor Computations for the NIST Ritz Free Air Chamber for Medium-Energy X Rays

Energy Technology Data Exchange (ETDEWEB)

Bergstrom, P [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 (United States)

2016-06-15

Purpose: The National Institute of Standards and Technology (NIST) uses 3 free-air chambers to establish primary standards for radiation dosimetry at x-ray energies. For medium-energy × rays, the Ritz free-air chamber is the main measurement device. In order to convert the charge or current collected by the chamber to the radiation quantities air kerma or air kerma rate, a number of correction factors specific to the chamber must be applied. Methods: We used the Monte Carlo codes EGSnrc and PENELOPE. Results: Among these correction factors are the diaphragm correction (which accounts for interactions of photons from the x-ray source in the beam-defining diaphragm of the chamber), the scatter correction (which accounts for the effects of photons scattered out of the primary beam), the electron-loss correction (which accounts for electrons that only partially expend their energy in the collection region), the fluorescence correction (which accounts for ionization due to reabsorption ffluorescence photons and the bremsstrahlung correction (which accounts for the reabsorption of bremsstrahlung photons). We have computed monoenergetic corrections for the NIST Ritz chamber for the 1 cm, 3 cm and 7 cm collection plates. Conclusion: We find good agreement with other’s results for the 7 cm plate. The data used to obtain these correction factors will be used to establish air kerma and it’s uncertainty in the standard NIST x-ray beams.

On the use of Gaia magnitudes and new tables of bolometric corrections

Science.gov (United States)

Casagrande, L.; VandenBerg, Don A.

2018-06-01

The availability of reliable bolometric corrections and reddening estimates, rather than the quality of parallaxes will be one of the main limiting factors in determining the luminosities of a large fraction of Gaia stars. With this goal in mind, we provide Gaia GBP, G, and GRP synthetic photometry for the entire MARCS grid, and test the performance of our synthetic colours and bolometric corrections against space-borne absolute spectrophotometry. We find indication of a magnitude-dependent offset in Gaia DR2 G magnitudes, which must be taken into account in high accuracy investigations. Our interpolation routines are easily used to derive bolometric corrections at desired stellar parameters, and to explore the dependence of Gaia photometry on Teff, log g, {[Fe/H]}, [α /{Fe}] and E(B - V). Gaia colours for the Sun and Vega, and Teff-dependent extinction coefficients, are also provided.

Determination of the self-attenuation correction factor for environmental samples analysis in gamma spectrometry

International Nuclear Information System (INIS)

Santos, Talita O.; Rocha, Zildete; Knupp, Eliana A.N.; Kastner, Geraldo F.; Oliveira, Arno H. de; Oliveira, Arno H. de

2015-01-01

Gamma spectrometry technique has been used in order to obtain the activity concentrations of natural and artificial radionuclides in environmental samples of different origins, compositions and densities. These samples characteristics may influence the calibration condition by the self-attenuation effect. The sample density has been considered the most important factor. For reliable results, it is necessary to determine self-attenuation correction factor which has been subject of great interest due to its effect on activity concentration. In this context, the aim of this work is to show the calibration process considering the correction by self-attenuation in the evaluation of the concentration of each radionuclide to a gamma HPGEe detector spectrometry system. (author)

SU-F-J-219: Predicting Ventilation Change Due to Radiation Therapy: Dependency On Pre-RT Ventilation and Effort Correction

Energy Technology Data Exchange (ETDEWEB)

Patton, T; Du, K; Bayouth, J [University of Wisconsin, Madison, WI (United States); Christensen, G; Reinhardt, J [University of Iowa, Iowa City, IA (United States)

2016-06-15

Purpose: Ventilation change caused by radiation therapy (RT) can be predicted using four-dimensional computed tomography (4DCT) and image registration. This study tested the dependency of predicted post-RT ventilation on effort correction and pre-RT lung function. Methods: Pre-RT and 3 month post-RT 4DCT images were obtained for 13 patients. The 4DCT images were used to create ventilation maps using a deformable image registration based Jacobian expansion calculation. The post-RT ventilation maps were predicted in four different ways using the dose delivered, pre-RT ventilation, and effort correction. The pre-RT ventilation and effort correction were toggled to determine dependency. The four different predicted ventilation maps were compared to the post-RT ventilation map calculated from image registration to establish the best prediction method. Gamma pass rates were used to compare the different maps with the criteria of 2mm distance-to-agreement and 6% ventilation difference. Paired t-tests of gamma pass rates were used to determine significant differences between the maps. Additional gamma pass rates were calculated using only voxels receiving over 20 Gy. Results: The predicted post-RT ventilation maps were in agreement with the actual post-RT maps in the following percentage of voxels averaged over all subjects: 71% with pre-RT ventilation and effort correction, 69% with no pre-RT ventilation and effort correction, 60% with pre-RT ventilation and no effort correction, and 58% with no pre-RT ventilation and no effort correction. When analyzing only voxels receiving over 20 Gy, the gamma pass rates were respectively 74%, 69%, 65%, and 55%. The prediction including both pre- RT ventilation and effort correction was the only prediction with significant improvement over using no prediction (p<0.02). Conclusion: Post-RT ventilation is best predicted using both pre-RT ventilation and effort correction. This is the only prediction that provided a significant

Determination of corrective factors for an ultrasonic flow measuring method in pipes accounting for perturbations

International Nuclear Information System (INIS)

Etter, S.

1982-01-01

By current ultrasonic flow measuring equipment (UFME) the mean velocity is measured for one or two measuring paths. This mean velocity is not equal to the velocity averaged over the flow cross-section, by means of which the flow rate is calculated. This difference will be found already for axially symmetrical, fully developed velocity profiles and, to a larger extent, for disturbed profiles varying in flow direction and for nonsteady flow. Corrective factors are defined for steady and nonsteady flows. These factors can be derived from the flow profiles within the UFME. By mathematical simulation of the entrainment effect the influence of cross and swirl flows on various ultrasonic measuring methods is studied. The applied UFME with crossed measuring paths is shown to be largely independent of cross and swirl flows. For evaluation in a computer of velocity network measurements in circular cross-sections the equations for interpolation and integration are derived. Results of the mathematical method are the isotach profile, the flow rate and, for fully developed flow, directly the corrective factor. In the experimental part corrective factors are determined in nonsteady flow in a measuring plane before and in form measuring planes behind a perturbation. (orig./RW) [de

Evaluation on correction factor for in-line X-ray phase contrast computed tomography

Energy Technology Data Exchange (ETDEWEB)

Jin, Mingli; Huang, Zhifeng; Zhang, Li; Zhang, Ran [Tsinghua Univ., Beijing (China). Dept. of Engineering Physics; Ministry of Education, Beijing (China). Key Laboratory of Particle and Radiation Imaging; Yin, Hongxia; Liu, Yunfu; Wang, Zhenchang [Capital Medical Univ., Beijing (China). Medical Imaging Center; Xiao, Tiqiao [Chinese Academy of Sciences, Shanghai (China). Shanghai Inst. of Applied Physics

2011-07-01

X-ray in-line phase contrast computed tomography (CT) is an effective nondestructive tool, providing 3D distribution of the refractive index of weakly absorbing low-Z object with high resolution and image contrast, especially with high-brilliance third-generation synchrotron radiation sources. Modified Bronnikov's algorithm (MBA), one of the in-line phase contrast CT reconstruction algorithms, can reconstruct the refractive index distribution of a pure phase object with a single computed tomographic data set. The key idea of the MBA is to use a correction factor in the filter function to stabilize the behavior at low frequencies. In this paper, we evaluate the influences of the correction factor to the final reconstruction results of the absorption-phase-mixed objects with analytical simulation and actual experiments. The limitations of the MBA are discussed finally. (orig.)

Three-loop corrections to the soft anomalous dimension in multileg scattering

CERN Document Server

Almelid, Øyvind; Gardi, Einan

2016-01-01

We present the three-loop result for the soft anomalous dimension governing long-distance singularities of multi-leg gauge-theory scattering amplitudes of massless partons. We compute all contributing webs involving semi-infinite Wilson lines at three loops and obtain the complete three-loop correction to the dipole formula. We find that non-dipole corrections appear already for three coloured partons, where the correction is a constant without kinematic dependence. Kinematic dependence appears only through conformally-invariant cross ratios for four coloured partons or more, and the result can be expressed in terms of single-valued harmonic polylogarithms of weight five. While the non-dipole three-loop term does not vanish in two-particle collinear limits, its contribution to the splitting amplitude anomalous dimension reduces to a constant, and it only depends on the colour charges of the collinear pair, thereby preserving strict collinear factorization properties. Finally we verify that our result is consi...

The real corrections to the virtual photon impact factor

International Nuclear Information System (INIS)

Kyrieleis, A.

2003-10-01

We investigate the interaction of two virtual photons in the high energy limit of quantum chromodynamics (QCD). We are motivated by two closely linked problems: the calculation of the γ * γ * total cross section, σ γ * γ * , in the framework NLO BFKL and the NLO extensions to the colour dipole picture. We calculate the squared amplitude for the process γ * + q → qqg + q in arbitrary space-time dimensions for both longitudinal and transverse photon polarisation. In transverse configuration space the result is found to factorise supporting in this way the photon wave function interpretation. This is the first step in the calculation of the qqg Fock component of the γ * wave function. The squared vertex for the transition Reggeon-γ * → qqg is extracted in order to calculate the NLO real corrections to the γ * impact factor. Together with the virtual corrections this will allow for the calculation of σ γ * γ * . The infrared divergences are dimensionally regularised and their cancellation against those from the virtual corrections is performed. After the introduction of Feynman parameters in each Feynman diagram, part of the qqg phase space integration is performed analytically. The various divergences emerging due to the independent treatment of the diagrams are regularised. A procedure is worked out to obtain for each diagram a finite phase space integral. In the case of longitudinal photon polarisation, this method is implemented in a computer program and the full phase space integration is carried out numerically. First numerical tests of the calculation are successfully performed. (orig.)

Interleaved segment correction achieves higher improvement factors in using genetic algorithm to optimize light focusing through scattering media

Science.gov (United States)

Li, Runze; Peng, Tong; Liang, Yansheng; Yang, Yanlong; Yao, Baoli; Yu, Xianghua; Min, Junwei; Lei, Ming; Yan, Shaohui; Zhang, Chunmin; Ye, Tong

2017-10-01

Focusing and imaging through scattering media has been proved possible with high resolution wavefront shaping. A completely scrambled scattering field can be corrected by applying a correction phase mask on a phase only spatial light modulator (SLM) and thereby the focusing quality can be improved. The correction phase is often found by global searching algorithms, among which Genetic Algorithm (GA) stands out for its parallel optimization process and high performance in noisy environment. However, the convergence of GA slows down gradually with the progression of optimization, causing the improvement factor of optimization to reach a plateau eventually. In this report, we propose an interleaved segment correction (ISC) method that can significantly boost the improvement factor with the same number of iterations comparing with the conventional all segment correction method. In the ISC method, all the phase segments are divided into a number of interleaved groups; GA optimization procedures are performed individually and sequentially among each group of segments. The final correction phase mask is formed by applying correction phases of all interleaved groups together on the SLM. The ISC method has been proved significantly useful in practice because of its ability to achieve better improvement factors when noise is present in the system. We have also demonstrated that the imaging quality is improved as better correction phases are found and applied on the SLM. Additionally, the ISC method lowers the demand of dynamic ranges of detection devices. The proposed method holds potential in applications, such as high-resolution imaging in deep tissue.

On self-attenuation corrections in gamma-ray spectrometry

International Nuclear Information System (INIS)

Bolivar, J.P.; Garcia-Leon, M.; Garcia-Tenorio, R.

1997-01-01

In this paper we discuss and justify the dependence on the sample density and gamma energy of the self-attenuation correction factor, f, in the transmission method for the full energy peak efficiency calibration of Ge detectors. It is suggested as a method for the direct computing of f in the case that the sample composition is known. (Author)

SU-F-T-23: Correspondence Factor Correction Coefficient for Commissioning of Leipzig and Valencia Applicators with the Standard Imaging IVB 1000

International Nuclear Information System (INIS)

Donaghue, J; Gajdos, S

2016-01-01

Purpose: To determine the correction factor of the correspondence factor for the Standard Imaging IVB 1000 well chamber for commissioning of Elekta’s Leipzig and Valencia skin applicators. Methods: The Leipzig and Valencia applicators are designed to treat small skin lesions by collimating irradiation to the treatment area. Published output factors are used to calculate dose rates for clinical treatments. To validate onsite applicators, a correspondence factor (CFrev) is measured and compared to published values. The published CFrev is based on well chamber model SI HDR 1000 Plus. The CFrev is determined by correlating raw values of the source calibration setup (Rcal,raw) and values taken when each applicator is mounted on the same well chamber with an adapter (Rapp,raw). The CFrev is calculated by using the equation CFrev =Rapp,raw/Rcal,raw. The CFrev was measured for each applicator in both the SI HDR 1000 Plus and the SI IVB 1000. A correction factor, CFIVB for the SI IVB 1000 was determined by finding the ratio of CFrev (SI IVB 1000) and CFrev (SI HDR 1000 Plus). Results: The average correction factors at dwell position 1121 were found to be 1.073, 1.039, 1.209, 1.091, and 1.058 for the Valencia V2, Valencia V3, Leipzig H1, Leipzig H2, and Leipzig H3 respectively. There were no significant variations in the correction factor for dwell positions 1119 through 1121. Conclusion: By using the appropriate correction factor, the correspondence factors for the Leipzig and Valencia surface applicators can be validated with the Standard Imaging IVB 1000. This allows users to correlate their measurements with the Standard Imaging IVB 1000 to the published data. The correction factor is included in the equation for the CFrev as follows: CFrev= Rapp,raw/(CFIVB*Rcal,raw). Each individual applicator has its own correction factor, so care must be taken that the appropriate factor is used.

Device-dependent activity estimation and decay correction of radionuclide mixtures with application to Tc-94m PET studies

International Nuclear Information System (INIS)

Smith, Mark F.; Daube-Witherspoon, Margaret E.; Plascjak, Paul S.; Szajek, Lawrence P.; Carson, Richard E.; Everett, James R.; Green, Shielah L.; Territo, Paul R.; Balaban, Robert S.; Bacharach, Stephen L.; Eckelman, William C.

2001-01-01

Multi-instrument activity estimation and decay correction techniques were developed for radionuclide mixtures, motivated by the desire for accurate quantitation of Tc-94m positron emission tomography (PET) studies. Tc-94m and byproduct Tc isotopes were produced by proton irradiation of enriched Mo-94 and natural Mo targets. Mixture activities at the end of bombardment were determined with a calibrated high purity germanium detector. The activity fractions of the greatest mixture impurities relative to 100% for Tc-94m averaged 10.0% (Tc-94g) and 3.3% (Tc-93) for enriched targets and 10.1% (Tc-94g), 11.0% (Tc-95), 255.8% (Tc-96m), and 7.2% (Tc-99m) for natural targets. These radioisotopes have different half-lives (e.g., 52.5 min for Tc-94m, 293 min for Tc-94g), positron branching ratios (e.g., 0.72 for Tc-94m, 0.11 for Tc-94g) and gamma ray emissions for themselves and their short-lived, excited Mo daughters. This complicates estimation of injected activity with a dose calibrator, in vivo activity with PET and blood sample activity with a gamma counter. Decay correction using only the Tc-94m half-life overestimates activity and is inadequate. For this reason analytic formulas for activity estimation and decay correction of radionuclide mixtures were developed. Isotope-dependent sensitivity factors for a PET scanner, dose calibrator, and gamma counter were determined using theoretical sensitivity models and fits of experimental decay curves to sums of exponentials with fixed decay rates. For up to 8 h after the end of bombardment with activity from enriched and natural Mo targets, decay-corrected activities were within 3% of the mean for three PET studies of a uniform cylinder, within 3% of the mean for six dose calibrator decay studies, and within 6% of the mean for four gamma counter decay studies. Activity estimation and decay correction for Tc-94m mixtures enable routine use of Tc-94m in quantitative PET, as illustrated by application to a canine Tc-94m sestamibi

Study of the replacement correction factors for ionization chamber dosimetry by Monte Carlo simulations

Science.gov (United States)

Wang, Lilie

In ionization chamber radiation dosimetry, the introduction of the ion chamber into medium will unavoidably distort the radiation field near the chamber because the chamber cavity material (air) is different from the medium. A replacement correction factor, Prepl was introduced in order to correct the chamber readings to give an accurate radiation dose in the medium without the presence of the chamber. Generally it is very hard to measure the values of Prepl since they are intertwined with the chamber wall effect. In addition, the P repl values always come together with the stopping-power ratio of the two media involved. This makes the problem of determining the P repl values even more complicated. Monte Carlo simulation is an ideal method to investigate the replacement correction factors. In this study, four different methods of calculating the values of Prepl by Monte Carlo simulation are discussed. Two of the methods are designated as 'direct' methods in the sense that the evaluation of the stopping-power ratio is not necessary. The systematic uncertainties of the two direct methods are estimated to be about 0.1-0.2% which comes from the ambiguous definition of the energy cutoff Delta used in the Spencer-Attix cavity theory. The two direct methods are used to calculate the values of P repl for both plane-parallel chambers and cylindrical thimble chambers in either electron beams or photon beams. The calculation results are compared to measurements. For electron beams, good agreements are obtained. For thimble chambers in photon beams, significant discrepancies are observed between calculations and measurements. The experiments are thus investigated and the procedures are simulated by the Monte Carlo method. It is found that the interpretation of the measured data as the replacement correction factors in dosimetry protocols are not correct. In applying the calculation to the BIPM graphite chamber in a 60Co beam, the calculated values of P repl differ from those

Time dependent view factor methods

International Nuclear Information System (INIS)

Kirkpatrick, R.C.

1998-03-01

View factors have been used for treating radiation transport between opaque surfaces bounding a transparent medium for several decades. However, in recent years they have been applied to problems involving intense bursts of radiation in enclosed volumes such as in the laser fusion hohlraums. In these problems, several aspects require treatment of time dependence

Determination of velocity correction factors for real-time air velocity monitoring in underground mines

OpenAIRE

Zhou, Lihong; Yuan, Liming; Thomas, Rick; Iannacchione, Anthony

2017-01-01

When there are installations of air velocity sensors in the mining industry for real-time airflow monitoring, a problem exists with how the monitored air velocity at a fixed location corresponds to the average air velocity, which is used to determine the volume flow rate of air in an entry with the cross-sectional area. Correction factors have been practically employed to convert a measured centerline air velocity to the average air velocity. However, studies on the recommended correction fac...

Photon energy-fluence correction factor in low energy brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Antunes, Paula C.G.; Yoriyaz, Hélio [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Vijande, Javier; Giménez-Alventosa, Vicent; Ballester, Facundo, E-mail: pacrisguian@gmail.com [Department of Atomic, Molecular, and Nuclear Physics and Instituto de Física Corpuscular (UV-CSIC), University of Valencia (Spain)

2017-07-01

The AAPM TG-43 brachytherapy dosimetry formalism has become a standard for brachytherapy dosimetry worldwide; it implicitly assumes that charged-particle equilibrium (CPE) exists for the determination of absorbed dose to water at different locations. At the time of relating dose to tissue and dose to water, or vice versa, it is usually assumed that the photon fluence in water and in tissues are practically identical, so that the absorbed dose in the two media can be related by their ratio of mass energy-absorption coefficients. The purpose of this work is to study the influence of photon energy-fluence in different media and to evaluate a proposal for energy-fluence correction factors for the conversion between dose-to-tissue (D{sub tis}) and dose-to-water (D{sub w}). State-of-the art Monte Carlo (MC) calculations are used to score photon fluence differential in energy in water and in various human tissues (muscle, adipose and bone) in two different codes, MCNP and PENELOPE, which in all cases include a realistic modeling of the {sup 125}I low-energy brachytherapy seed in order to benchmark the formalism proposed. A correction is introduced that is based on the ratio of the water-to-tissue photon energy-fluences using the large-cavity theory. In this work, an efficient way to correlate absorbed dose to water and absorbed dose to tissue in brachytherapy calculations at clinically relevant distances for low-energy photon emitting seed is proposed. The energy-fluence based corrections given in this work are able to correlate absorbed dose to tissue and absorbed dose to water with an accuracy better than 0.5% in the most critical cases. (author)

Photon energy-fluence correction factor in low energy brachytherapy

International Nuclear Information System (INIS)

Antunes, Paula C.G.; Yoriyaz, Hélio; Vijande, Javier; Giménez-Alventosa, Vicent; Ballester, Facundo

2017-01-01

The AAPM TG-43 brachytherapy dosimetry formalism has become a standard for brachytherapy dosimetry worldwide; it implicitly assumes that charged-particle equilibrium (CPE) exists for the determination of absorbed dose to water at different locations. At the time of relating dose to tissue and dose to water, or vice versa, it is usually assumed that the photon fluence in water and in tissues are practically identical, so that the absorbed dose in the two media can be related by their ratio of mass energy-absorption coefficients. The purpose of this work is to study the influence of photon energy-fluence in different media and to evaluate a proposal for energy-fluence correction factors for the conversion between dose-to-tissue (D tis ) and dose-to-water (D w ). State-of-the art Monte Carlo (MC) calculations are used to score photon fluence differential in energy in water and in various human tissues (muscle, adipose and bone) in two different codes, MCNP and PENELOPE, which in all cases include a realistic modeling of the 125 I low-energy brachytherapy seed in order to benchmark the formalism proposed. A correction is introduced that is based on the ratio of the water-to-tissue photon energy-fluences using the large-cavity theory. In this work, an efficient way to correlate absorbed dose to water and absorbed dose to tissue in brachytherapy calculations at clinically relevant distances for low-energy photon emitting seed is proposed. The energy-fluence based corrections given in this work are able to correlate absorbed dose to tissue and absorbed dose to water with an accuracy better than 0.5% in the most critical cases. (author)

Identifying influential factors of business process performance using dependency analysis

Science.gov (United States)

Wetzstein, Branimir; Leitner, Philipp; Rosenberg, Florian; Dustdar, Schahram; Leymann, Frank

2011-02-01

We present a comprehensive framework for identifying influential factors of business process performance. In particular, our approach combines monitoring of process events and Quality of Service (QoS) measurements with dependency analysis to effectively identify influential factors. The framework uses data mining techniques to construct tree structures to represent dependencies of a key performance indicator (KPI) on process and QoS metrics. These dependency trees allow business analysts to determine how process KPIs depend on lower-level process metrics and QoS characteristics of the IT infrastructure. The structure of the dependencies enables a drill-down analysis of single factors of influence to gain a deeper knowledge why certain KPI targets are not met.

Perturbative corrections to Λ_b→Λ form factors from QCD light-cone sum rules

International Nuclear Information System (INIS)

Wang, Yu-Ming; Shen, Yue-Long

2016-01-01

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.

Theoretical study of band gap in CuAlO2: Pressure dependence and self-interaction correction

International Nuclear Information System (INIS)

Nakanishi, Akitaka; Katayama-Yoshida, Hiroshi

2012-01-01

By using first-principles calculations, we studied the energy gaps of delafossite CuAlO 2 : (1) pressure dependence and (2) self-interaction correction (SIC). Our simulation shows that CuAlO 2 transforms from a delafossite structure to a leaning delafossite structure at 60 GPa. The energy gap of CuAlO 2 increases through the structural transition due to the enhanced covalency of Cu 3d and O 2p states. We implemented a self-interaction correction (SIC) into first-principles calculation code to go beyond local density approximation and applied it to CuAlO 2 . The energy gap calculated within the SIC is close to experimental data while one calculated without the SIC is about 1 eV smaller than the experimental data.

Advanteges of using Two-Switch Forward in Single-Stage Power Factor Corrected Power Supplies

DEFF Research Database (Denmark)

Petersen, Lars

2000-01-01

A single-Stage power factor corrected power supply using a two-switch forward is proposed to increase efficiency. The converter is operated in the DCM (Discontinues Conduction Mode). This will insure the intermediate DC-bus to be controlled only by means of circuit parameters and therefore...... power supply has been implemented. The measured efficiency and power factor are about 87% and 0.96 respectively....

The temperature dependence of the static structure factor for liquid 4He below Tsub(lambda)

International Nuclear Information System (INIS)

Puoskari, M.; Kallio, A.; Pollari, P.

1984-01-01

The temperature dependence of the structure factor S(k,T) is studied based on an assumption that the anomalous behaviour of S(k,T) below Tsub(lambda) is due to thermally excited rotons and phonons. The calculation of S(k,T) is performed with the help of the HNC-equation from a model density matrix of Penrose which in turn is obtained from a quasiparticle Hamiltonian describing elementary excitations of liquid helium (both phonons and rotons). The results are in qualitative agreement with recent neutron and X-ray scattering experiments below Tsub(lambda). The theoretical temperature correction is used to deduce S(k,T=0) separately from the most recent X-ray and neutron scattering experiments. (Auth.)

Tissue factor-dependent activation of tritium-labeled factor IX and factor X in human plasma

International Nuclear Information System (INIS)

Morrison, S.A.; Jesty, J.

1984-01-01

A comparism was made of the tissue factor-dependent activation of tritium-labeled factor IX and factor X in a human plasma system and a study was made of the role of proteases known to stimulate factor VII activity. Plasma was defibrinated by heating and depleted of its factors IX and X by passing it through antibody columns. Addition of human brain thromboplastin, Ca2+, and purified 3H-labeled factor X to the plasma resulted, after a short lag, in burst-like activation of the factor X, measured as the release of radiolabeled activation peptide. The progress of activation was slowed by both heparin and a specific inhibitor of factor Xa but factor X activation could not be completely abolished by such inhibitors. In the case of 3H-factor IX activation, the rate also increased for approximately 3 min after addition of thromboplastin, but was not subsequently curtailed. A survey of proteases implicated as activators of factor VII in other settings showed that both factor Xa and factor IXa could accelerate the activation of factor IX. However, factor Xa was unique in obliterating activation when present at concentrations greater than approximately 1 nM. Heparin inhibited the tissue factor-dependent activation of factor IX almost completely, apparently through the effect of antithrombin on the feedback reactions of factors Xa and IXa on factor VII. These results suggest that a very tight, biphasic control of factor VII activity exists in human plasma, which is modulated mainly by factor Xa. At saturation of factor VIIa/tissue factor, factor IX activation was significantly more rapid than was previously found in bovine plasma under similar conditions. The activation of factor X at saturation was slightly more rapid than in bovine plasma, despite the presence of heparin

Determination of small field synthetic single-crystal diamond detector correction factors for CyberKnife, Leksell Gamma Knife Perfexion and linear accelerator.

Science.gov (United States)

Veselsky, T; Novotny, J; Pastykova, V; Koniarova, I

2017-12-01

The aim of this study was to determine small field correction factors for a synthetic single-crystal diamond detector (PTW microDiamond) for routine use in clinical dosimetric measurements. Correction factors following small field Alfonso formalism were calculated by comparison of PTW microDiamond measured ratio M Qclin fclin /M Qmsr fmsr with Monte Carlo (MC) based field output factors Ω Qclin,Qmsr fclin,fmsr determined using Dosimetry Diode E or with MC simulation itself. Diode measurements were used for the CyberKnife and Varian Clinac 2100C/D linear accelerator. PTW microDiamond correction factors for Leksell Gamma Knife (LGK) were derived using MC simulated reference values from the manufacturer. PTW microDiamond correction factors for CyberKnife field sizes 25-5 mm were mostly smaller than 1% (except for 2.9% for 5 mm Iris field and 1.4% for 7.5 mm fixed cone field). The correction of 0.1% and 2.0% for 8 mm and 4 mm collimators, respectively, needed to be applied to PTW microDiamond measurements for LGK Perfexion. Finally, PTW microDiamond M Qclin fclin /M Qmsr fmsr for the linear accelerator varied from MC corrected Dosimetry Diode data by less than 0.5% (except for 1 × 1 cm 2 field size with 1.3% deviation). Regarding low resulting correction factor values, the PTW microDiamond detector may be considered an almost ideal tool for relative small field dosimetry in a large variety of stereotactic and radiosurgery treatment devices. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Exploitation of jet properties for energy scale corrections for the CMS calorimeters

International Nuclear Information System (INIS)

Kirschenmann, Henning

2011-02-01

Jets form important event signatures in proton-proton collisions at the Large Hadron Collider (LHC) and the precise measurement of their energy is a crucial premise for a manifold of physics studies. Jets, which are reconstructed exclusively from calorimeter information, have been widely used within the CMS collaboration. However, the response of the calorimeters to incident particles depends heavily on their energy. In addition, it has been observed at previous experiments that the charged particle multiplicity and the radial distribution of constituents differ for jets induced by light quarks or by gluons. In conjunction with the non-linearity of the CMS calorimeters, this contributes to a mean energy response deviating from unity for calorimeter jets, depending on the jet-flavour. This thesis describes a jet-energy correction to be applied in addition to the default corrections within the CMS collaboration. This correction aims at decreasing the flavour dependence of the jet-energy response and improving the energy resolution. As many different effects contribute to the observed jet-energy response, a set of observables are introduced and corrections based on these observables are tested with respect to the above aims. A jet-width variable, which is defined from energy measured in the calorimeter, shows the best performance: A correction based on this observable improves the energy resolution by up to 20% at high transverse momenta in the central detector region and decreases the flavour dependence of the jet-energy response by a factor of two. A parametrisation of the correction is both derived from and validated on simulated data. First results from experimental data, to which the correction has been applied, are presented. The proposed jet-width correction shows a promising level of performance. (orig.)

Exploitation of jet properties for energy scale corrections for the CMS calorimeters

Energy Technology Data Exchange (ETDEWEB)

Kirschenmann, Henning

2011-02-15

Jets form important event signatures in proton-proton collisions at the Large Hadron Collider (LHC) and the precise measurement of their energy is a crucial premise for a manifold of physics studies. Jets, which are reconstructed exclusively from calorimeter information, have been widely used within the CMS collaboration. However, the response of the calorimeters to incident particles depends heavily on their energy. In addition, it has been observed at previous experiments that the charged particle multiplicity and the radial distribution of constituents differ for jets induced by light quarks or by gluons. In conjunction with the non-linearity of the CMS calorimeters, this contributes to a mean energy response deviating from unity for calorimeter jets, depending on the jet-flavour. This thesis describes a jet-energy correction to be applied in addition to the default corrections within the CMS collaboration. This correction aims at decreasing the flavour dependence of the jet-energy response and improving the energy resolution. As many different effects contribute to the observed jet-energy response, a set of observables are introduced and corrections based on these observables are tested with respect to the above aims. A jet-width variable, which is defined from energy measured in the calorimeter, shows the best performance: A correction based on this observable improves the energy resolution by up to 20% at high transverse momenta in the central detector region and decreases the flavour dependence of the jet-energy response by a factor of two. A parametrisation of the correction is both derived from and validated on simulated data. First results from experimental data, to which the correction has been applied, are presented. The proposed jet-width correction shows a promising level of performance. (orig.)

Home radon levels and seasonal correction factors for the Isle of Man

International Nuclear Information System (INIS)

Grainger, P.; Preece, A.W.; Goodfellow, S.A.

2000-01-01

Ionizing radiation dose levels due to home radon can rise to levels that would be illegal for workers in the nuclear industry. It is well known that radon levels within homes and from home to home, and also from month to month, vary considerably. To define an Isle of Man radon seasonal correction factor, readings were taken in eight homes over a 12 month period. An average island indoor exposure of 48 Bq m -3 (range 4-518 Bq m -3 ) was determined from 285 homes selected from a cohort of 1300 families participating in the European Longitudinal Study of Pregnancy and Childhood (ELSPAC) in the Isle of Man. This compares with a UK home average of 20 Bq m -3 and a European Union average (excluding UK) of 68 Bq m -3 . Ten homes of those measured were found to have radon levels above the National Radiological Protection Board 200 Bq m -3 action level. There are 29 377 homes on the Isle of Man, suggesting that there could be some 900 or more homes above the action level. No statistical difference was found between the NRPB and Isle of Man seasonal correction factors. (author)

Communication: Orbital instabilities and triplet states from time-dependent density functional theory and long-range corrected functionals

Science.gov (United States)

Sears, John S.; Koerzdoerfer, Thomas; Zhang, Cai-Rong; Brédas, Jean-Luc

2011-10-01

Long-range corrected hybrids represent an increasingly popular class of functionals for density functional theory (DFT) that have proven to be very successful for a wide range of chemical applications. In this Communication, we examine the performance of these functionals for time-dependent (TD)DFT descriptions of triplet excited states. Our results reveal that the triplet energies are particularly sensitive to the range-separation parameter; this sensitivity can be traced back to triplet instabilities in the ground state coming from the large effective amounts of Hartree-Fock exchange included in these functionals. As such, the use of standard long-range corrected functionals for the description of triplet states at the TDDFT level is not recommended.

Transverse spin dependent Drell Yan in QCD to O(αs2) at large pΤ. 1: Virtual corrections and methods for the real emissions

International Nuclear Information System (INIS)

Chang, S.; Coriano, C.; Elwood, J.K.

1997-01-01

The authors investigate the role of the transverse spin dependence in Drell Yan lepton pair production to NLO in QCD at parton level. In the analysis the authors deal with the large p Τ distributions. They give very compact expressions for the virtual O(α s 2 ) corrections to the cross section and show that the singularities factorize. The study is performed in the MS scheme in Dimensional Regularization, and with the t'Hooft-Veltman prescription for γ 5 . A discussion of the structure of the real emissions is included, and detailed methods for the study of these contributions are formulated

Do leukocyte telomere length dynamics depend on baseline telomere length? An analysis that corrects for ‘regression to the mean’

International Nuclear Information System (INIS)

Verhulst, Simon; Aviv, Abraham; Benetos, Athanase; Berenson, Gerald S.; Kark, Jeremy D.

2013-01-01

Leukocyte telomere length (LTL) shortens with age. Longitudinal studies have reported accelerated LTL attrition when baseline LTL is longer. However, the dependency of LTL attrition on baseline LTL might stem from a statistical artifact known as regression to the mean (RTM). To our knowledge no published study of LTL dynamics (LTL and its attrition rate) has corrected for this phenomenon. We illustrate the RTM effect using replicate LTL measurements, and show, using simulated data, how the RTM effect increases with a rise in stochastic measurement variation (representing LTL measurement error), resulting in spurious increasingly elevated dependencies of attrition on baseline values. In addition, we re-analyzed longitudinal LTL data collected from four study populations to test the hypothesis that LTL attrition depends on baseline LTL. We observed that the rate of LTL attrition was proportional to baseline LTL, but correction for the RTM effect reduced the slope of the relationship by 57 % when measurement error was low (coefficient of variation ∼2 %). A modest but statistically significant effect remained however, indicating that high baseline LTL is associated with higher LTL attrition even when correcting for the RTM effect. Baseline LTL explained 1.3 % of the variation in LTL attrition, but this effect, which differed significantly between the study samples, appeared to be primarily attributable to the association in men (3.7 %)

Correction factors for safe performance of API X65 pipeline steel

International Nuclear Information System (INIS)

Hashemi, Sayyed H.

2009-01-01

Prediction of required Charpy energy for fracture arrest is vital for safe performance of gas transportation pipelines. This is commonly estimated through failure models calibrated in the past on fracture data from combined Charpy tests and full-thickness burst experiments. Unfortunately, such pipeline failure models are unable to correctly predict the minimum arrest toughness of thermo-mechanical controlled rolled (TMCR) steels. To refine the existing failure models, different empirical adjustments have been proposed in recent years. In this paper, similar correction factors were derived from fracture information of instrumented Charpy impact tests on API X65 steel. The contribution of different fracture mechanisms of impact test specimens was determined through energy partitioning analysis. Parts of the energy contribution were correlated then to the source of uncertainty observed in similar experiments. The applied technique was similar to that of previous studies on X70 and X100 steels, and proved to be encouraging in giving consistent results compared to available test data.

Correction of X-ray diffraction profiles in linear-type PSPC by position factor

International Nuclear Information System (INIS)

Takahashi, Toshio

1992-01-01

PSPC (Position Sensitive Proportional Counter) makes it possible to obtain one-dimentional diffraction profiles without mechanical scanning. In a linear-type PSPC, the obtained profiles need correcting, because the position factor influences the intensity of the diffracted X-ray beam and the counting rate at each position on PSPC. The distances from the specimen are not the same at the center and at the edge of the detector, and the intensity decreases at the edge because of radiation and absorption. The counting rate varies with the incident angle of the diffracted beam at each position on PSPC. The position factor f i at channel i of the multichannel-analyser is given by f i = cos 4 α i ·exp{-μR(1/cosα i -1)} where R is the distance between the specimen and the center of PSPC, μ is the linear absorption coefficient and α i is the incident angle of the diffracted beam at channel i. The background profiles of silica gel powder were measured with CrKα and CuKα. The parameters of the model function were fitted to the profiles by the non-linear least squares method. The agreement between these parameters and the calculated values shows that the position factor can correct the measured profiles properly. (author)

Correction factors of commercial radionuclide calibrators for several measurement geometries of radiopharmaceuticals

International Nuclear Information System (INIS)

Correia, Amanda Ribeiro

2011-01-01

In order to reach therapy and diagnosis objectives, the activity must be determined with high accuracy to administer a radiopharmaceutical to a patient. Initially, a glass vial with the radiopharmaceutical is placed into the radionuclide calibrator to determine its activity. Subsequently, an aliquot is transferred to a syringe and again its activity is measured on the calibrator before being administered to the patient. The glass vial and the syringe are different in many aspects as the calibration factors too, which may cause incorrect activities administered to the patient. This study aims to determine the correction factors, as well as the values of the uncertainties associated to two distinct models of calibrators: one that uses ionization chamber and another Geiger-Mueller as detectors. The radionuclides chosen were 99 Tc m and 123 1 and the containers were glass vials (type lOR and P6) and plastic syringes of 3 and 5 mL. The correction factors for each type of vials or syringe were determined as a function of volume and type of calibrator. Activity measurements comparison was also made involving several radionuclide calibrators of different models belonging to four nuclear medicine hospitals and to National Metrology Laboratory of lionizing Radiation (LNMRI). In the measurements of activity values larger than allowed by CNEN NN-3.05 norm, results have shown deviations for syringes in calibrator with Geiger-Mueller detectors and for both radionuclides. (author)

Current s - quark mass corrections to the form factors of D - meson semileptonic decays

International Nuclear Information System (INIS)

Hussain, F.; Ivanov, A.N.; Troitskaya, N.I.

1994-11-01

The infinite mass effective theory, when a heavy quark mass tends to infinity, and Chiral perturbation theory at the quark level, based on the extended Nambu - Jona - Lasinio model with linear realization of chiral U(3) x U(3) symmetry, are applied to the calculations of current s - quark mass corrections to the form factors of the D → K-bar e + ν e and D → K-bar * e + ν e decays. These corrections turn out to be quite significant, of the order of 7 - 20%. The theoretical results are compared with experimental data. (author). 17 refs

Quality correction factors of composite IMRT beam deliveries: Theoretical considerations

International Nuclear Information System (INIS)

Bouchard, Hugo

2012-01-01

Purpose: In the scope of intensity modulated radiation therapy (IMRT) dosimetry using ionization chambers, quality correction factors of plan-class-specific reference (PCSR) fields are theoretically investigated. The symmetry of the problem is studied to provide recommendable criteria for composite beam deliveries where correction factors are minimal and also to establish a theoretical limit for PCSR delivery k Q factors. Methods: The concept of virtual symmetric collapsed (VSC) beam, being associated to a given modulated composite delivery, is defined in the scope of this investigation. Under symmetrical measurement conditions, any composite delivery has the property of having a k Q factor identical to its associated VSC beam. Using this concept of VSC, a fundamental property of IMRT k Q factors is demonstrated in the form of a theorem. The sensitivity to the conditions required by the theorem is thoroughly examined. Results: The theorem states that if a composite modulated beam delivery produces a uniform dose distribution in a volume V cyl which is symmetric with the cylindrical delivery and all beams fulfills two conditions in V cyl : (1) the dose modulation function is unchanged along the beam axis, and (2) the dose gradient in the beam direction is constant for a given lateral position; then its associated VSC beam produces no lateral dose gradient in V cyl , no matter what beam modulation or gantry angles are being used. The examination of the conditions required by the theorem lead to the following results. The effect of the depth-dose gradient not being perfectly constant with depth on the VSC beam lateral dose gradient is found negligible. The effect of the dose modulation function being degraded with depth on the VSC beam lateral dose gradient is found to be only related to scatter and beam hardening, as the theorem holds also for diverging beams. Conclusions: The use of the symmetry of the problem in the present paper leads to a valuable theorem showing

Hadron mass corrections in semi-inclusive deep inelastic scattering

International Nuclear Information System (INIS)

Accardi, A.; Hobbs, T.; Melnitchouk, W.

2009-01-01

We derive mass corrections for semi-inclusive deep inelastic scattering of leptons from nucleons using a collinear factorization framework which incorporates the initial state mass of the target nucleon and the final state mass of the produced hadron h. The hadron mass correction is made by introducing a generalized, finite-Q 2 scaling variable ζ h for the hadron fragmentation function, which approaches the usual energy fraction z h = E h /ν in the Bjorken limit. We systematically examine the kinematic dependencies of the mass corrections to semi-inclusive cross sections, and find that these are even larger than for inclusive structure functions. The hadron mass corrections compete with the experimental uncertainties at kinematics typical of current facilities, Q 2 2 and intermediate x B > 0.3, and will be important to efforts at extracting parton distributions from semi-inclusive processes at intermediate energies.

Uncertainties in the correction factors as the dose polarization and recombination at different energies

International Nuclear Information System (INIS)

Alejo Luque, L.; Rodriguez Romero, R.; Castro Tejero, P.; Fandino Lareo, J. M.

2011-01-01

This paper discusses the measures and uncertainties of the correction factors for dose-polarization (k, 1) and recombination (k,) of different ionization chambers plane-parallel and cylindrical. The values ??have been obtained using photon and electron beams of various energies generated by linear accelerators nominal Varian 21EX CLJNAC Tomotherapy Hi-Art and JI. We study the cases in which you can avoid the application of the factors obtained, according to the criteria proposed

Model correction factor method for reliability problems involving integrals of non-Gaussian random fields

DEFF Research Database (Denmark)

Franchin, P.; Ditlevsen, Ove Dalager; Kiureghian, Armen Der

2002-01-01

The model correction factor method (MCFM) is used in conjunction with the first-order reliability method (FORM) to solve structural reliability problems involving integrals of non-Gaussian random fields. The approach replaces the limit-state function with an idealized one, in which the integrals ...

A Novel Bridgeless Power Factor Correction with Interleaved Boost Stages in Continous Current Mode

DEFF Research Database (Denmark)

Li, Qingnan; Andersen, Michael A. E.; Thomsen, Ole Cornelius

2011-01-01

The operation and trade-off of Bridgeless Power Factor Correction (BPFC) circuit with interleaved Boost stages are investigated. By using interleaved BPFC, an overall reduction of the size of EMI filter can be achieved without increasing the switching frequency of the converter. And higher...

How to simplify transmission-based scatter correction for clinical application

International Nuclear Information System (INIS)

Baccarne, V.; Hutton, B.F.

1998-01-01

Full text: The performances of ordered subsets (OS) EM reconstruction including attenuation, scatter and spatial resolution correction are evaluated using cardiac Monte Carlo data. We demonstrate how simplifications in the scatter model allow one to correct SPECT data for scatter in terms of quantitation and quality in a reasonable time. Initial reconstruction of the 20% window is performed including attenuation correction (broad beam μ values), to estimate the activity quantitatively (accuracy 3%), but not spatially. A rough reconstruction with 2 iterations (subset size: 8) is sufficient for subsequent scatter correction. Estimation of primary photons is obtained by projecting the previous distribution including attenuation (narrow beam μ values). Estimation of the scatter is obtained by convolving the primary estimates by a depth dependent scatter kernel, and scaling the result by a factor calculated from the attenuation map. The correction can be accelerated by convolving several adjacent planes with the same kernel, and using an average scaling factor. Simulation of the effects of the collimator during the scatter correction was demonstrated to be unnecessary. Final reconstruction is performed using 6 iterations OSEM, including attenuation (narrow beam μ values) and spatial resolution correction. Scatter correction is implemented by incorporating the estimated scatter as a constant offset in the forward projection step. The total correction + reconstruction (64 proj. 40x128 pixel) takes 38 minutes on a Sun Sparc 20. Quantitatively, the accuracy is 7% in a reconstructed slice. The SNR inside the whole myocardium (defined from the original object), is equal to 2.1 and 2.3 - in the corrected and the primary slices respectively. The scatter correction preserves the myocardium to ventricle contrast (primary: 0.79, corrected: 0.82). These simplifications allow acceleration of correction without influencing the quality of the result

Development of the heated length to diameter correction factor on critical heat flux using the artificial neural networks

Energy Technology Data Exchange (ETDEWEB)

Lee, Yong Ho; Baek, Won Pil; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Chun, Tae Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1999-12-31

With using artificial neural networks (ANNs), an analytical study related to the heated length effect on critical heat flux (CHF) has been carried out to make an improvement of the CHF prediction accuracy based on local condition correlations or table. It has been carried out to suggest a feasible criterion of the threshold length-to-diameter (L/D) value in which heated length could affect CHF. And within the criterion, a L/D correction factor has been developed through conventional regression. In order to validate the developed L/D correction factor, CHF experiments for various heated lengths have been carried out under low and intermediate pressure conditions. The developed threshold L/D correlation provides a new feasible criterion of L/D threshold value. The developed correction factor gives a reasonable accuracy for the original database, showing the error of -2.18% for average and 27.75% for RMS, and promising results for new experimental data. 7 refs., 12 figs., 1 tab. (Author)

Development of the heated length to diameter correction factor on critical heat flux using the artificial neural networks

Energy Technology Data Exchange (ETDEWEB)

Lee, Yong Ho; Baek, Won Pil; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Chun, Tae Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1998-12-31

With using artificial neural networks (ANNs), an analytical study related to the heated length effect on critical heat flux (CHF) has been carried out to make an improvement of the CHF prediction accuracy based on local condition correlations or table. It has been carried out to suggest a feasible criterion of the threshold length-to-diameter (L/D) value in which heated length could affect CHF. And within the criterion, a L/D correction factor has been developed through conventional regression. In order to validate the developed L/D correction factor, CHF experiments for various heated lengths have been carried out under low and intermediate pressure conditions. The developed threshold L/D correlation provides a new feasible criterion of L/D threshold value. The developed correction factor gives a reasonable accuracy for the original database, showing the error of -2.18% for average and 27.75% for RMS, and promising results for new experimental data. 7 refs., 12 figs., 1 tab. (Author)

Proximity formulae for folding potentials. [Saxon-Woods form factors, first order corrections

Energy Technology Data Exchange (ETDEWEB)

Schechter, H; Canto, L F [Rio de Janeiro Univ. (Brazil). Inst. de Fisica

1979-03-05

The proximity formulae of Brink and Stancu are applied to folding potentials. A numerical study is made for the case of single folding potentials with Saxon-Woods form factors. It is found that a proximity formula is accurate to 1-2% at separations of the order of the radius of the Coulomb barrier and that first order corrections due to first curvature are important. The approximations involved are discussed.

Validity and factor structure of the bodybuilding dependence scale

OpenAIRE

Smith, D; Hale, B

2004-01-01

Objectives: To investigate the factor structure, validity, and reliability of the bodybuilding dependence scale and to investigate differences in bodybuilding dependence between men and women and competitive and non-competitive bodybuilders.

ac driving amplitude dependent systematic error in scanning Kelvin probe microscope measurements: Detection and correction

International Nuclear Information System (INIS)

Wu Yan; Shannon, Mark A.

2006-01-01

The dependence of the contact potential difference (CPD) reading on the ac driving amplitude in scanning Kelvin probe microscope (SKPM) hinders researchers from quantifying true material properties. We show theoretically and demonstrate experimentally that an ac driving amplitude dependence in the SKPM measurement can come from a systematic error, and it is common for all tip sample systems as long as there is a nonzero tracking error in the feedback control loop of the instrument. We further propose a methodology to detect and to correct the ac driving amplitude dependent systematic error in SKPM measurements. The true contact potential difference can be found by applying a linear regression to the measured CPD versus one over ac driving amplitude data. Two scenarios are studied: (a) when the surface being scanned by SKPM is not semiconducting and there is an ac driving amplitude dependent systematic error; (b) when a semiconductor surface is probed and asymmetric band bending occurs when the systematic error is present. Experiments are conducted using a commercial SKPM and CPD measurement results of two systems: platinum-iridium/gap/gold and platinum-iridium/gap/thermal oxide/silicon are discussed

Tension-Induced Error Correction and Not Kinetochore Attachment Status Activates the SAC in an Aurora-B/C-Dependent Manner in Oocytes.

Science.gov (United States)

Vallot, Antoine; Leontiou, Ioanna; Cladière, Damien; El Yakoubi, Warif; Bolte, Susanne; Buffin, Eulalie; Wassmann, Katja

2018-01-08

Cell division with partitioning of the genetic material should take place only when paired chromosomes named bivalents (meiosis I) or sister chromatids (mitosis and meiosis II) are correctly attached to the bipolar spindle in a tension-generating manner. For this to happen, the spindle assembly checkpoint (SAC) checks whether unattached kinetochores are present, in which case anaphase onset is delayed to permit further establishment of attachments. Additionally, microtubules are stabilized when they are attached and under tension. In mitosis, attachments not under tension activate the so-named error correction pathway depending on Aurora B kinase substrate phosphorylation. This leads to microtubule detachments, which in turn activates the SAC [1-3]. Meiotic divisions in mammalian oocytes are highly error prone, with severe consequences for fertility and health of the offspring [4, 5]. Correct attachment of chromosomes in meiosis I leads to the generation of stretched bivalents, but-unlike mitosis-not to tension between sister kinetochores, which co-orient. Here, we set out to address whether reduction of tension applied by the spindle on bioriented bivalents activates error correction and, as a consequence, the SAC. Treatment of oocytes in late prometaphase I with Eg5 kinesin inhibitor affects spindle tension, but not attachments, as we show here using an optimized protocol for confocal imaging. After Eg5 inhibition, bivalents are correctly aligned but less stretched, and as a result, Aurora-B/C-dependent error correction with microtubule detachment takes place. This loss of attachments leads to SAC activation. Crucially, SAC activation itself does not require Aurora B/C kinase activity in oocytes. Copyright © 2017 Elsevier Ltd. All rights reserved.

SU-F-BRD-15: Quality Correction Factors in Scanned Or Broad Proton Therapy Beams Are Indistinguishable

International Nuclear Information System (INIS)

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

2015-01-01

Purpose: The IAEA TRS-398 code of practice details the reference conditions for reference dosimetry of proton beams using ionization chambers and the required beam quality correction factors (kQ). Pencil beam scanning (PBS) requires multiple spots to reproduce the reference conditions. The objective is to demonstrate, using Monte Carlo (MC) calculations, that kQ factors for broad beams can be used for scanned beams under the same reference conditions with no significant additional uncertainty. We consider hereafter the general Alfonso formalism (Alfonso et al, 2008) for non-standard beam. Methods: To approach the reference conditions and the associated dose distributions, PBS must combine many pencil beams with range modulation and shaping techniques different than those used in passive systems (broad beams). This might lead to a different energy spectrum at the measurement point. In order to evaluate the impact of these differences on kQ factors, ion chamber responses are computed with MC (Geant4 9.6) in a dedicated scanned pencil beam (Q-pcsr) producing a 10×10cm2 composite field with a flat dose distribution from 10 to 16 cm depth. Ion chamber responses are also computed by MC in a broad beam with quality Q-ds (double scattering). The dose distribution of Q -pcsr matches the dose distribution of Q-ds. k-(Q-pcsr,Q-ds) is computed for a 2×2×0.2cm 3 idealized air cavity and a realistic plane-parallel ion chamber (IC). Results: Under reference conditions, quality correction factors for a scanned composite field versus a broad beam are the same for air cavity dose response, k-(Q-pcsr,Q-ds) =1.001±0.001 and for a Roos IC, k-(Q-pcsr,Q-ds) =0.999±0.005. Conclusion: Quality correction factors for ion chamber response in scanned and broad proton therapy beams are identical under reference conditions within the calculation uncertainties. The results indicate that quality correction factors published in IAEA TRS-398 can be used for scanned beams in the SOBP of a high

SU-F-BRD-15: Quality Correction Factors in Scanned Or Broad Proton Therapy Beams Are Indistinguishable

Energy Technology Data Exchange (ETDEWEB)

Sorriaux, J; Lee, J [Molecular Imaging Radiotherapy & Oncology, Universite Catholique de Louvain, Brussels (Belgium); ICTEAM Institute, Universite catholique de Louvain, Louvain-la-Neuve (Belgium); Testa, M; Paganetti, H [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, Massachusetts (United States); Bertrand, D; Orban de Xivry, J [Ion Beam Applications, Louvain-la-neuve, Brabant Wallon (Belgium); Palmans, H [EBG MedAustron GmbH, Wiener Neustadt (Austria); National Physical Laboratory, Teddington (United Kingdom); Vynckier, S [Cliniques Universitaires Saint-Luc, Brussels (Belgium); Sterpin, E [Molecular Imaging Radiotherapy & Oncology, Universite Catholique de Louvain, Brussels (Belgium)

2015-06-15

Purpose: The IAEA TRS-398 code of practice details the reference conditions for reference dosimetry of proton beams using ionization chambers and the required beam quality correction factors (kQ). Pencil beam scanning (PBS) requires multiple spots to reproduce the reference conditions. The objective is to demonstrate, using Monte Carlo (MC) calculations, that kQ factors for broad beams can be used for scanned beams under the same reference conditions with no significant additional uncertainty. We consider hereafter the general Alfonso formalism (Alfonso et al, 2008) for non-standard beam. Methods: To approach the reference conditions and the associated dose distributions, PBS must combine many pencil beams with range modulation and shaping techniques different than those used in passive systems (broad beams). This might lead to a different energy spectrum at the measurement point. In order to evaluate the impact of these differences on kQ factors, ion chamber responses are computed with MC (Geant4 9.6) in a dedicated scanned pencil beam (Q-pcsr) producing a 10×10cm2 composite field with a flat dose distribution from 10 to 16 cm depth. Ion chamber responses are also computed by MC in a broad beam with quality Q-ds (double scattering). The dose distribution of Q -pcsr matches the dose distribution of Q-ds. k-(Q-pcsr,Q-ds) is computed for a 2×2×0.2cm{sup 3} idealized air cavity and a realistic plane-parallel ion chamber (IC). Results: Under reference conditions, quality correction factors for a scanned composite field versus a broad beam are the same for air cavity dose response, k-(Q-pcsr,Q-ds) =1.001±0.001 and for a Roos IC, k-(Q-pcsr,Q-ds) =0.999±0.005. Conclusion: Quality correction factors for ion chamber response in scanned and broad proton therapy beams are identical under reference conditions within the calculation uncertainties. The results indicate that quality correction factors published in IAEA TRS-398 can be used for scanned beams in the SOBP of a

Refitting density dependent relativistic model parameters including Center-of-Mass corrections

International Nuclear Information System (INIS)

Avancini, Sidney S.; Marinelli, Jose R.; Carlson, Brett Vern

2011-01-01

Full text: Relativistic mean field models have become a standard approach for precise nuclear structure calculations. After the seminal work of Serot and Walecka, which introduced a model Lagrangian density where the nucleons interact through the exchange of scalar and vector mesons, several models were obtained through its generalization, including other meson degrees of freedom, non-linear meson interactions, meson-meson interactions, etc. More recently density dependent coupling constants were incorporated into the Walecka-like models, which are then extensively used. In particular, for these models a connection with the density functional theory can be established. Due to the inherent difficulties presented by field theoretical models, only the mean field approximation is used for the solution of these models. In order to calculate finite nuclei properties in the mean field approximation, a reference set has to be fixed and therefore the translational symmetry is violated. It is well known that in such case spurious effects due to the center-of-mass (COM) motion are present, which are more pronounced for light nuclei. In a previous work we have proposed a technique based on the Pierls-Yoccoz projection operator applied to the mean-field relativistic solution, in order to project out spurious COM contributions. In this work we obtain a new fitting for the density dependent parameters of a density dependent hadronic model, taking into account the COM corrections. Our fitting is obtained taking into account the charge radii and binding energies for He 4 , O 16 , Ca 40 , Ca 48 , Ni 56 , Ni 68 , Sn 100 , Sn 132 and Pb 208 . We show that the nuclear observables calculated using our fit are of a quality comparable to others that can be found in the literature, with the advantage that now a translational invariant many-body wave function is at our disposal. (author)

Power Factor Correction Capacitors for Multiple Parallel Three-Phase ASD Systems

DEFF Research Database (Denmark)

Yang, Yongheng; Blaabjerg, Frede

2017-01-01

Today’s three-phase Adjustable Speed Drive (ASD) systems still employ Diode Rectifiers (DRs) and Silicon-Controlled Rectifiers (SCRs) as the front-end converters due to structural and control simplicity, small volume, low cost, and high reliability. However, the uncontrollable DRs and phase......-controllable SCRs bring side-effects by injecting high harmonics to the grid, which will degrade the system performance in terms of lowering the overall efficiency and overheating the system if remain uncontrolled or unattenuated. For multiple ASD systems, certain harmonics in the entire system can be mitigated...... the power factor, passive capacitors can be installed, which yet can trigger the system resonance. Hence, this paper analyzes the resonant issues in multiple ASD systems with power factor correction capacitors. Potential damping solutions are summarized. Simulations are carried out, while laboratory tests...

Calculation of beam quality correction factor using Monte Carlo simulation

International Nuclear Information System (INIS)

Kawachi, T.; Saitoh, H.; Myojoyama, A.; Katayose, T.; Kojima, T.; Fukuda, K.; Inoue, M.

2005-01-01

In recent years, a number of the CyberKnife systems (Accuray C., U.S.) have been increasing significantly. However, the CyberKnife has unique treatment head structure and beam collimating system. Therefore, the global standard protocols can not be adopted for absolute absorbed dose dosimetry in CyberKnife beam. In this work, the energy spectrum of photon and electron from CyberKnife treatment head at 80 cm SSD and several depths in water are simulated with conscientious geometry using by the EGS Monte Carlo method. Furthermore, for calculation of the beam quality correction factor k Q , the mean restricted mass stopping power and the mass energy absorption coefficient of air, water and several chamber wall and waterproofing sleeve materials are calculated. As a result, the factors k Q CyberKnife beam for several ionization chambers are determined. And the relationship between the beam quality index PDD(10) x in CyberKnife beam and k Q is described in this report. (author)

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

International Nuclear Information System (INIS)

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

2014-01-01

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 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 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)

Conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation 1948--1951

International Nuclear Information System (INIS)

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

Factors related to stability following the surgical correction of skeletal open bite.

Science.gov (United States)

Ito, Goshi; Koh, Myongsun; Fujita, Tadashi; Shirakura, Maya; Ueda, Hiroshi; Tanne, Kazuo

2014-05-01

If a skeletal anterior open bite malocclusion is treated by orthognathic surgery directed only at the mandible, the lower jaw is repositioned upward in a counter-clockwise rotation. However, this procedure has a high risk of relapse. In the present study, the key factors associated with post-surgical stability of corrected skeletal anterior open bite malocclusions were investigated. Eighteen orthognathic patients were subjected to cephalometric analysis to assess the dental and skeletal changes following mandibular surgery for the correction of an anterior open bite. The patients were divided into two groups, determined by an increase or decrease in nasion-menton (N-Me) distance as a consequence of surgery. Changes in overbite, the displacements of molars and positional changes in Menton were evaluated immediately before and after surgery and after a minimum of one year post-operatively. The group with a decreased N-Me distance exhibited a significantly greater backward positioning of the mandible. The group with an increased N-Me distance experienced significantly greater dentoalveolar extrusion of the lower molars. A sufficient mandibular backward repositioning is an effective technique in the prevention of open bite relapse. In addition, it is important not to induce molar extrusion during post-surgical orthodontic treatment to preserve stability of the surgical open bite correction.

SU-C-201-06: Small Field Correction Factors for the MicroDiamond Detector in the Gamma Knife-Model C Derived Using Monte Carlo Methods

International Nuclear Information System (INIS)

Barrett, J C; Knill, C

2016-01-01

Purpose: To determine small field correction factors for PTW’s microDiamond detector in Elekta’s Gamma Knife Model-C unit. These factors allow the microDiamond to be used in QA measurements of output factors in the Gamma Knife Model-C; additionally, the results also contribute to the discussion on the water equivalence of the relatively-new microDiamond detector and its overall effectiveness in small field applications. Methods: The small field correction factors were calculated as k correction factors according to the Alfonso formalism. An MC model of the Gamma Knife and microDiamond was built with the EGSnrc code system, using BEAMnrc and DOSRZnrc user codes. Validation of the model was accomplished by simulating field output factors and measurement ratios for an available ABS plastic phantom and then comparing simulated results to film measurements, detector measurements, and treatment planning system (TPS) data. Once validated, the final k factors were determined by applying the model to a more waterlike solid water phantom. Results: During validation, all MC methods agreed with experiment within the stated uncertainties: MC determined field output factors agreed within 0.6% of the TPS and 1.4% of film; and MC simulated measurement ratios matched physically measured ratios within 1%. The final k correction factors for the PTW microDiamond in the solid water phantom approached unity to within 0.4%±1.7% for all the helmet sizes except the 4 mm; the 4 mm helmet size over-responded by 3.2%±1.7%, resulting in a k factor of 0.969. Conclusion: Similar to what has been found in the Gamma Knife Perfexion, the PTW microDiamond requires little to no corrections except for the smallest 4 mm field. The over-response can be corrected via the Alfonso formalism using the correction factors determined in this work. Using the MC calculated correction factors, the PTW microDiamond detector is an effective dosimeter in all available helmet sizes. The authors would like to

SU-C-201-06: Small Field Correction Factors for the MicroDiamond Detector in the Gamma Knife-Model C Derived Using Monte Carlo Methods

Energy Technology Data Exchange (ETDEWEB)

Barrett, J C [Wayne State University, Detroit, MI (United States); Karmanos Cancer Institute McLaren-Macomb, Clinton Township, MI (United States); Knill, C [Wayne State University, Detroit, MI (United States); Beaumont Hospital, Canton, MI (United States)

2016-06-15

Purpose: To determine small field correction factors for PTW’s microDiamond detector in Elekta’s Gamma Knife Model-C unit. These factors allow the microDiamond to be used in QA measurements of output factors in the Gamma Knife Model-C; additionally, the results also contribute to the discussion on the water equivalence of the relatively-new microDiamond detector and its overall effectiveness in small field applications. Methods: The small field correction factors were calculated as k correction factors according to the Alfonso formalism. An MC model of the Gamma Knife and microDiamond was built with the EGSnrc code system, using BEAMnrc and DOSRZnrc user codes. Validation of the model was accomplished by simulating field output factors and measurement ratios for an available ABS plastic phantom and then comparing simulated results to film measurements, detector measurements, and treatment planning system (TPS) data. Once validated, the final k factors were determined by applying the model to a more waterlike solid water phantom. Results: During validation, all MC methods agreed with experiment within the stated uncertainties: MC determined field output factors agreed within 0.6% of the TPS and 1.4% of film; and MC simulated measurement ratios matched physically measured ratios within 1%. The final k correction factors for the PTW microDiamond in the solid water phantom approached unity to within 0.4%±1.7% for all the helmet sizes except the 4 mm; the 4 mm helmet size over-responded by 3.2%±1.7%, resulting in a k factor of 0.969. Conclusion: Similar to what has been found in the Gamma Knife Perfexion, the PTW microDiamond requires little to no corrections except for the smallest 4 mm field. The over-response can be corrected via the Alfonso formalism using the correction factors determined in this work. Using the MC calculated correction factors, the PTW microDiamond detector is an effective dosimeter in all available helmet sizes. The authors would like to

Correcting atmospheric effects on InSAR with MERIS water vapour data and elevation-dependent interpolation model

KAUST Repository

Li, Z. W.; Xu, Wenbin; Feng, G. C.; Hu, J.; Wang, C. C.; Ding, X. L.; Zhu, J. J.

2012-01-01

The propagation delay when radar signals travel from the troposphere has been one of the major limitations for the applications of high precision repeat-pass Interferometric Synthetic Aperture Radar (InSAR). In this paper, we first present an elevation-dependent atmospheric correction model for Advanced Synthetic Aperture Radar (ASAR—the instrument aboard the ENVISAT satellite) interferograms with Medium Resolution Imaging Spectrometer (MERIS) integrated water vapour (IWV) data. Then, using four ASAR interferometric pairs over Southern California as examples, we conduct the atmospheric correction experiments with cloud-free MERIS IWV data. The results show that after the correction the rms differences between InSAR and GPS have reduced by 69.6 per cent, 29 per cent, 31.8 per cent and 23.3 per cent, respectively for the four selected interferograms, with an average improvement of 38.4 per cent. Most importantly, after the correction, six distinct deformation areas have been identified, that is, Long Beach–Santa Ana Basin, Pomona–Ontario, San Bernardino and Elsinore basin, with the deformation velocities along the radar line-of-sight (LOS) direction ranging from −20 mm yr−1 to −30 mm yr−1 and on average around −25 mm yr−1, and Santa Fe Springs and Wilmington, with a slightly low deformation rate of about −10 mm yr−1 along LOS. Finally, through the method of stacking, we generate a mean deformation velocity map of Los Angeles over a period of 5 yr. The deformation is quite consistent with the historical deformation of the area. Thus, using the cloud-free MERIS IWV data correcting synchronized ASAR interferograms can significantly reduce the atmospheric effects in the interferograms and further better capture the ground deformation and other geophysical signals.

Correcting atmospheric effects on InSAR with MERIS water vapour data and elevation-dependent interpolation model

KAUST Repository

Li, Z. W.

2012-05-01

The propagation delay when radar signals travel from the troposphere has been one of the major limitations for the applications of high precision repeat-pass Interferometric Synthetic Aperture Radar (InSAR). In this paper, we first present an elevation-dependent atmospheric correction model for Advanced Synthetic Aperture Radar (ASAR—the instrument aboard the ENVISAT satellite) interferograms with Medium Resolution Imaging Spectrometer (MERIS) integrated water vapour (IWV) data. Then, using four ASAR interferometric pairs over Southern California as examples, we conduct the atmospheric correction experiments with cloud-free MERIS IWV data. The results show that after the correction the rms differences between InSAR and GPS have reduced by 69.6 per cent, 29 per cent, 31.8 per cent and 23.3 per cent, respectively for the four selected interferograms, with an average improvement of 38.4 per cent. Most importantly, after the correction, six distinct deformation areas have been identified, that is, Long Beach–Santa Ana Basin, Pomona–Ontario, San Bernardino and Elsinore basin, with the deformation velocities along the radar line-of-sight (LOS) direction ranging from −20 mm yr−1 to −30 mm yr−1 and on average around −25 mm yr−1, and Santa Fe Springs and Wilmington, with a slightly low deformation rate of about −10 mm yr−1 along LOS. Finally, through the method of stacking, we generate a mean deformation velocity map of Los Angeles over a period of 5 yr. The deformation is quite consistent with the historical deformation of the area. Thus, using the cloud-free MERIS IWV data correcting synchronized ASAR interferograms can significantly reduce the atmospheric effects in the interferograms and further better capture the ground deformation and other geophysical signals.

Analytical Design of Passive LCL Filter for Three-phase Two-level Power Factor Correction Rectifiers

DEFF Research Database (Denmark)

Kouchaki, Alireza; Nymand, Morten

2017-01-01

This paper proposes a comprehensive analytical LCL filter design method for three-phase two-level power factor correction rectifiers (PFCs). The high frequency converter current ripple generates the high frequency current harmonics that need to be attenuated with respect to the grid standards...

Determination of recombination and polarity correction factors, kS and kP, for small cylindrical ionization chambers PTW 31021 and PTW 31022 in pulsed filtered and unfiltered beams.

Science.gov (United States)

Bruggmoser, Gregor; Saum, Rainer; Kranzer, Rafael

2018-01-12

The aim of this technical communication is to provide correction factors for recombination and polarity effect for two new ionization chambers PTW PinPoint 3D (type 31022) and PTW Semiflex 3D (type 31021). The correction factors provided are for the (based on the) German DIN 6800-2 dosimetry protocol and the AAPM TG51 protocol. The measurements were made in filtered and unfiltered high-energy photon beams in a water equivalent phantom at maximum depth of the PDD and a field size on the surface of 10cm×10cm. The design of the new chamber types leads to an ion collection efficiency and a polarity effect that are well within the specifications requested by pertinent dosimetry protocols including the addendum of TG-51. It was confirmed that the recombination effect of both chambers mainly depends on dose per pulse and is independent of the filtration of the photon beam. Copyright © 2018. Published by Elsevier GmbH.

Profile correction to electron temperature and enhancement factor in soft-x-ray pulse-height-analysis measurements in tokamaks

International Nuclear Information System (INIS)

Sesnic, S.; Diesso, M.; Hill, K.; Holland, A.; Pohl, F.

1988-01-01

Because soft-x-ray pulse-height-analysis spectra contain chordal information, the electron temperature and the radiation intensity (enhancement factor) measurements do not represent the local values. The correction factors for the electron temperature and the enhancement factor as a function of the temperature and density profile parameters and the energy are obtained. The spectrum distortion due to pulse pileup effects is also evaluated. A set of curves is given from which the distortion of the spectrum can be obtained if the electron temperature, the Be filter thickness, and the electronic parameters of the acquisition system are known. PG 1810,1812 ID 131801CON N X-ray diagnostics TT Profile correction to electron temperature and enhancement factor in soft-x-ray pulse-height-analysis measurements in tokamaks AU S. Sesnic, M. Diesso, K. Hill, and A. Holland LO Princeton University, Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 AU F. Pohl LO Max-Planck Institut fuer Plasmaphysik, 8046-Garching, Federal Republic of Germany SD (Presented on 16 March 1988) AB Because soft-x-ray pulse-height-analysis spectra contain chordal information, the electron temperature and the radiation intensity (enhancement factor) measurements do not represent the local values. The correction factors for the electron temperature and the enhancement factor as a function of the temperature and density profile parameters and the energy are obtained. The spectrum distortion due to pulse pileup effects is also evaluated. A set of curves is given from which the distortion of the spectrum can be obtained if the electron tempe

NLO supersymmetric QCD corrections to tt-bar h0 associated production at hadron colliders

International Nuclear Information System (INIS)

Wu Peng; Ma Wengan; Hou Hongsheng; Zhang Renyou; Han Liang; Jiang Yi

2005-01-01

We calculate NLO QCD corrections to the lightest neutral Higgs boson production associated with top quark pair at hadron colliders in the minimal supersymmetric standard model (MSSM). Our calculation shows that the total QCD correction significantly reduces its dependence on the renormalization/factorization scale. The relative correction from the SUSY QCD part approaches to be a constant, if either M S or m g- bar is heavy enough. The corrections are generally moderate (in the range of few percent to 20%) and under control in most of the SUSY parameter space. The relative correction is obviously related to m g- bar , A t and μ, but not very sensitive to tanβ, M S at both the Tevatron and the LHC with our specified parameters

Inhibition of factor-dependent transcription termination in ...

Indian Academy of Sciences (India)

Inhibition of factor-dependent transcription termination in Escherichia coli might relieve xenogene silencing by abrogating. H-NS-DNA interactions in vivo. DEEPTI CHANDRAPRAKASH and ASWIN SAI NARAIN SESHASAYEE. Chromatin immunoprecipitation. MG1655 hns::3xFLAG cells were grown in liquid LB me-.

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

International Nuclear Information System (INIS)

Soh, R; Lee, J; Harianto, F

2014-01-01

Purpose: To determine and compare the correction factors obtained for TLDs in 2 × 2cm 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 3 , 2.64g/cm 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 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 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 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

All-cause mortality in HIV-positive adults starting combination antiretroviral therapy: correcting for loss to follow-up.

Science.gov (United States)

Anderegg, Nanina; Johnson, Leigh F; Zaniewski, Elizabeth; Althoff, Keri N; Balestre, Eric; Law, Matthew; Nash, Denis; Shepherd, Bryan E; Yiannoutsos, Constantin T; Egger, Matthias

2017-04-01

To estimate mortality in HIV-positive patients starting combination antiretroviral therapy (ART) and to discuss different approaches to calculating correction factors to account for loss to follow-up. A total of 222 096 adult HIV-positive patients who started ART 2009-2014 in clinics participating in the International epidemiology Databases to Evaluate AIDS collaboration in 43 countries in sub-Saharan Africa, Asia Pacific, Latin America, and North America were included. To allow for underascertainment of deaths due to loss to follow-up, two correction factors (one for the period 0-6 months on ART and one for later periods) or 168 correction factors (combinations of two sexes, three time periods after ART initiation, four age groups, and seven CD4 groups) based on tracing patients lost in Kenya and data linkages in South Africa were applied. Corrected mortality rates were compared with a worst case scenario assuming all patients lost to follow-up had died. Loss to follow-up differed between regions; rates were lowest in central Africa and highest in east Africa. Compared with using two correction factors (1.64 for the initial ART period and 2.19 for later), applying 168 correction factors (range 1.03-4.75) more often resulted in implausible mortality rates that exceeded the worst case scenario. Corrected mortality rates varied widely, ranging from 0.2 per 100 person-years to 54 per 100 person-years depending on region and covariates. Implausible rates were less common with the simpler approach based on two correction factors. The corrected mortality rates will be useful to international agencies, national programmes, and modellers.

Field size dependence of wedge factor: miniphantom vs full phantom measurements

International Nuclear Information System (INIS)

Allen Li, X.; Szanto, J.; Soubra, M.; Gerig, L. H.

1995-01-01

It is empirically known that the transmission factor for wedge in a high-energy photon beam is dependent upon field size and depth of measurement. The field-size dependence of wedge factors may be attributed to changes in (i) head scatter, (ii) phantom scatter, and (iii) backscatter from the wedge into the linac monitor chamber. In this work we present the results of studies designed to examine each of these factors in isolation. The wedge factors for wedges with nominal wedge angles of 15 deg. , 30 deg. , 45 deg. and 60 deg. were measured with a 3-g/cm 2 -diameter narrow cylindrical phantom (miniphantom), a brass cap with 1.5-g/cm 2 side-wall thickness and a full water phantom for 6-, 10- and 18-MV photon beams. The measurements were performed with and without flattening filter in place. The wedge factors measured with the miniphantom and the brass cap exclude the phantom scatter contribution. It has been found that the field-size behaviour of wedge factor measured with full water phantom is similar to that measured with the miniphantom and cap. This indicates that the head scatter radiation is the major contributor to the field size dependence of wedge factors. Wedge factors measured with water phantom are up to 5.0% smaller than those measured with miniphantom. This difference increases with wedge angle. When Measured with the flattening filter removed, the field size dependence of the wedge factor is reduced. This justify that the flattening filter is one of the major contributors to head scatters. The measurement results made with the brass cap agree well with those made by using the miniphantom. By measuring the monitor chamber output, it is found that the backscatters from the wedge into the linac ion chamber have little effect on the field size dependence of the wedge factor

DETECTING AND CORRECTING MOTION BLUR FROM IMAGES SHOT WITH CHANNEL-DEPENDENT EXPOSURE TIME

Directory of Open Access Journals (Sweden)

L. Lelégard

2012-07-01

Full Text Available This article describes a pipeline developed to automatically detect and correct motion blur due to the airplane motion in aerial images provided by a digital camera system with channel-dependent exposure times. Blurred images show anisotropy in their Fourier Transform coefficients that can be detected and estimated to recover the characteristics of the motion blur. To disambiguate the anisotropy produced by a motion blur from the possible spectral anisotropy produced by some periodic patterns present in a sharp image, we consider the phase difference of the Fourier Transform of two channel shot with different exposure times (i.e. with different blur extensions. This is possible because of the deep correlation between the three visible channels ensures phase coherence of the Fourier Transform coefficients in sharp images. In this context, considering the phase difference constitutes both a good detector and estimator of the motion blur parameters. In order to improve on this estimation, the phase difference is performed on local windows in the image where the channels are more correlated. The main lobe of the phase difference, where the phase difference between two channels is close to zero actually imitates an ellipse which axis ratio discriminates blur and which orientation and minor axis give respectively the orientation and the blur kernel extension of the long exposure-time channels. However, this approach is not robust to the presence in the phase difference of minor lobes due to phase sign inversions in the Fourier transform of the motion blur. They are removed by considering the polar representation of the phase difference. Based on the blur detection step, blur correction is eventually performed using two different approaches depending on the blur extension size: using either a simple frequency-based fusion for small blur or a semi blind iterative method for larger blur. The higher computing costs of the latter method make it only

Prevalence and risk factors for Sick Building Syndrome among Italian correctional officers: A pilot study

Directory of Open Access Journals (Sweden)

Francesco Chirico

2017-03-01

Full Text Available Introduction: Over the past two decades, numerous studies on indoor air and the Sick Building Syndrome (SBS have been conducted, mostly in office environments. However, there is little knowledge about SBS in police officers. This study was aimed to fill this gap. Methods: A cross-sectional questionnaire survey was conducted in 2016 at the Triveneto Penitentiary Center, Northern Italy. Chi-square was used to test the difference of prevalence between office workers (OWs and correctional officers (COs of personal characteristics, cases of SBS, and general and mucocutaneous symptoms associated with SBS. A binary logistic regression was used to identify among individual, environmental, and psychosocial characteristics, factors associated with correctional officers’ Sick Building Syndrome. Results: Chi-squared analyses revealed that there were statistically significant differences in the estimated prevalence of SBS general symptoms (χ2 (1 = 12.22, P < .05, SBS mucocutaneous symptoms (χ2 (1 = 9.04, P < .05, and cases of SBS (χ2 (1 = 4.39, P <.05 between COs and OWs. COs reported that their health had been affected by the passive smoking (β = 2.34, P < .05 and unpleasant odour (β = 2.51, P < .05 as environmental risk factors; work-family conflict (β = 2.14, P < .05, psychological and physical isolation (β = 2.07, P < .05, and negative public image (β = 2.06, P < .05 as psychosocial risk factors. Finally, atopy (β = 2.02, P < .05 and to be current smoker (β = 2.02, P < .05 were statistically significant behavioral predictors of SBS among correctional officers. Discussion: Our survey showed that symptoms compatible with the sick building syndrome are common in correctional officers and that psychosocial work climate and exposure to passive smoking could have a strong influence on the prevalence of both general and mucocutaneous symptoms associated with SBS. A health policy for passive tobacco smoking within prisons, and for work-related stress

Next-to-Leading-Order QCD Corrections to Higgs Boson Plus Jet Production with Full Top-Quark Mass Dependence

Science.gov (United States)

Jones, S. P.; Kerner, M.; Luisoni, G.

2018-04-01

We present the next-to-leading-order QCD corrections to the production of a Higgs boson in association with one jet at the LHC including the full top-quark mass dependence. The mass of the bottom quark is neglected. The two-loop integrals appearing in the virtual contribution are calculated numerically using the method of sector decomposition. We study the Higgs boson transverse momentum distribution, focusing on the high pt ,H region, where the top-quark loop is resolved. We find that the next-to-leading-order QCD corrections are large but that the ratio of the next-to-leading-order to leading-order result is similar to that obtained by computing in the limit of large top-quark mass.

DIAGNOSIS OF RISK FACTORS FOR BEER DEPENDENCE IN YOUNG PEOPLE

Directory of Open Access Journals (Sweden)

G. A. Novikova

2017-10-01

Full Text Available In the article the approach to identification of factors influencing beer consumption by young people. Describes the author’s methodology, identifying biological, social, psychological, pedagogical and economic risk factors of development of beer dependence in young people. The data obtained using the proposed methodology can be used to identify risk groups according to the dependent behavior and planning of preventive measures.

Attenuation correction using simultaneous emission - transmission tomography

International Nuclear Information System (INIS)

Ljubenov, V.; Marinkovic, P.

1998-01-01

In order to reduce degrading influence of attenuation on SPECT image quality, possibility for correction, based on simultaneous emission / transmission measurements, is discussed. Numerical photon transport simulations through the phantom and acquisition of of tomographic projections are performed by using Monte Carlo code MCNP-4A. Amount of contamination in transmission data due to photon Compton scattering for emission energy window is specially analyzed and appropriate spatial depending 'noise / signal' factors for three different external sources, applied with Tc-99m, are determined (author)

Perancangan Zeta Converter yang dilengkapi Power Factor Correction pada Aplikasi Pengaturan Kecepatan Motor Brushless DC

Directory of Open Access Journals (Sweden)

Adhika Prajna Nandiwardhana

2017-01-01

Full Text Available Penggunaan motor brushless DC telah banyak digunakan dalam berbagai bidang seperti peralatan rumah tangga maupun industri dikarenakan motor ini memiliki struktur yang sederhana, efisiensi dan torsi yang tinggi, serta menggunakan konsep komutasi elektris yang berbeda dari motor DC lainnya. Namun pengoperasian pada umumnya yang menggunakan sumber AC, penyearah serta inverter membuat tingginya nilai harmonisa arus (THD sebesar 73,33% dan power factor sebesar 0,803 dimana nilai ini kurang baik dalam pengaplikasiannya. Pada penelitian ini akan dikaji mengenai proses power factor correction yang mereduksi harmonisa arus (THD sumber AC dengan menggunakan zeta converter dalam pengaplikasian motor brushless DC, serta pengoperasian motor dengan mengamati respon motor terhadap kecepatan referensi yang berubah-ubah dan mengamati kestabilan motor terhadap pembebanan yang bervariasi. Dalam menerapkan metode yang dilakukan pada penelitian ini, pengoperasian motor brushless DC yang telah dirancang dapat bekerja dengan baik meliputi respon motor yang dapat mengikuti kecepatan referensi yang berubah-ubah, serta kestabilan motor dalam mempertahankan kecepatannya pada pembebanan yang bervariasi. Proses power factor correction dapat meningkatkan kualitas daya pada berbagai kecepatan dan mode penerapan yang berbeda-beda, dimana peningkatan tersebut membuktikan kinerja yang baik dalam sistem ini dan memiliki nilai kualitas daya yang baik.

Fault of the correction factor for pressure and temperature kPT in the atmospheric conditions of Dosimetric Calibration Lab. - LSCD of ININ - Mexico

International Nuclear Information System (INIS)

Alvarez R, Jose T.; Jesus Cejudo, A.; La Cruz H., Daniel de; Tovar M, Victor M.

2013-01-01

The realization of the operational quantities H*, Hp y/0 H'(0.07) for estimating the effective dose E, usually is done by measuring the air kerma Ka air within the field of ionizing radiation of interest and was subsequently applied appropriate conversion factors for both the quality of radiation and the operational quantity of interest. However, the SSDL in performing the Ka to environmental conditions of ININ (3000 m above sea level, P ∼ 710 hPa) with ionization chambers has found that the pressure correction factor and kPT temperature is not sufficient to correct the change in air density. Indeed, in the case of 60 Co the discrepancy between the measurement of a primary standard graphite walls Ka (BEV CC01 be 131) and a side of the plastic walls (Exradin A12) is on the order of 0.4% for the case of the RX BIPM qualities to 100,135, 180 and 250 kV. It was found that for a camera model 30001 PTW (PMMA graphite wall) is needed an additional correction factor k PT ranging from 0.4% to 1.5%, correction factor calculated by MC simulation. For Sk of 125 I brachytherapy sources was given an additional correction lower in 11% compared to conventional k PT value measured with a well chamber Standard Imaging HDR 1000 plus. Finally, it is in the process of studying the behavior of this additional correction factor to the case of 137 Cs

Monte Carlo study of thermal flux profiles and body correction factors for body protein measurements of obese subjects

International Nuclear Information System (INIS)

McGregor, B.J.; Allen, B.J.

1991-01-01

In previous calculations for total body nitrogen measurements of children, the anterior/posterior thermal neutron flux profile with depth was found to be fairly flat after an initial rise. However, for obese adults significant variations are found in the flux profile with the central flux value being as low as 20% of the peak value. The significance of these flux variations is examined. Correction factors are calculated for the varying attenuation of the nitrogen and hydrogen photons by a range of obese bodies. The calculations included the effect of the thermal flux profile as well as that of an outer layer of low nitrogen content adipose tissue. The bodies are assumed to have a homogeneous hydrogen content. A study of four obese body models with varying sex and fat content shows that the correction factors do not vary much between males and females. This is surprising since the female models are assumed to have a surface fat layer twice as thick as for the male models. The correction factors are found to be only slightly sensitive to the thermal flux variations with depth. 5 refs., 1 tab., 4 figs

DMPD: Type I interferon [corrected] gene induction by the interferon regulatory factorfamily of transcription factors. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 16979567 Type I interferon [corrected] gene induction by the interferon regulatory factorfamily...ng) (.svg) (.html) (.csml) Show Type I interferon [corrected] gene induction by the interferon regulatory factorfamily...orrected] gene induction by the interferon regulatory factorfamily of transcription factors. Authors Honda K

Description of corrections on electrode polarization impedance using isopotential interface factor

Directory of Open Access Journals (Sweden)

John Alexander Gomez Sanchez

2012-08-01

Full Text Available In this paper, we propose an equation and define the Isopotential Interface Factor (IIF to quantify the contribution of electrode polarization impedance in two tetrapolar electrode shapes. The first tetrapolar electrode geometry shape was adjacent and the second axial concentric, both probes were made of stainless steel (AISI 304. The experiments were carried out with an impedance analyzer (Solartron 1260 using a frequency range between 0.1 Hz and 8 MHz. Based on a theoretical simplification, the experimental results show a lower value of the IIF in the axial concentric tetrapolar electrode system which caused a lower correction of interface value. The higher value of the IIF in the adjacent electrode system was KEEI (1Hz, 0.28 mS/cm = 1.41 and decreased when the frequency and conductance were increased, whereas in the axial concentric electrode system was KEEI (1Hz, 0.28 mS/cm = 0.08. The average isopotential interface factor throughout the whole range of conductivities and frequencies was 0.23 in the adjacent electrode system and 0.02 in the axial concentric electrode system. The index of inherent electrical anisotropy (IEA was used to present an analysis of electrical anisotropy of biceps brachii muscle in vitro using the corrections of both tetrapolar electrode systems. A higher IEA was present in lower frequency where the variation below 1 kHz was 15 % in adjacent electrode configuration and 26 % in the axial concentric probe with respect to full range. The IIF is then shown that it can be used to describe the quality of an electrode system.

Domain shape dependence of semiclassical corrections to energy

International Nuclear Information System (INIS)

Kwiatkowski, Grzegorz

2017-01-01

Stationary solution of a one-dimensional sine-Gordon system is embedded in a multidimensional theory with an explicitly finite domain in the added spatial dimensions. Semiclassical corrections to energy are calculated for a static kink solution with emphasis on the impact of the scale of the domain as well as the choice of boundary conditions on the results for a rectangular cross-section. (paper)

Correction of magnetization sextupole in one-meter long dipole magnets using passing superconductor

International Nuclear Information System (INIS)

Green, M.A.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Gilbert, W.S.; Green, M.I.; Scanlan, R.M.

1990-03-01

The generation of higher multipoles due to the magnetization of the superconductor in the dipoles of the SSC is a problem during injection of the beam into the machine. The use of passive superconductor was proposed some years ago to correct the magnetization sextupole in the dipole magnet. This paper presents the LBL test results in which the magnetization sextupole was greatly reduced in two one-meter long dipole magnets by the use of passive superconductor mounted on the magnet bore tube. The magnetization sextupole was reduced a factor of five on one magnet and a factor of eight on the other magnet using this technique. Magnetization decapole was also reduced by the passive superconductor. The passive superconductor method of correction also reduced the temperature dependence of the magnetization multipoles. In addition, the drift in the magnetization sextupole due to flux creep was also reduced. Passive superconductor correction appears to be a promising method of correcting out the effects of superconductor magnetization in SSC dipoles and quadrupoles. 10 refs., 6 figs

The spin-dependent neutralino-nucleus form factor for 127I

International Nuclear Information System (INIS)

Ressell, M.T.

1996-01-01

We present the results of detailed shell model calculations of the spin-dependent elastic form factor for the nucleus 127 I. the calculations were performed in extremely large model spaces which adequately describe the configuration mixing in this nucleus. Good agreement between the calculated and experimental values of the magnetic moment are found. Other nuclear observables are also compared to experiment. The dependence of the form factor upon the model space and effective interaction is discussed

Finite size vertex correction to the strong decay of ηc and χc states and a determination of αs(mc)

International Nuclear Information System (INIS)

Ping Ronggang; Jiang Huanqing; Zou Bingsong

2002-01-01

In previous calculations of the strong decay of a charmonium, the first-order momentum dependence of the quark propagator is kept. It was found that the finite-size vertex correction to the Γ(J/ψ→3g) process is large. The authors calculate the two-gluon decay widths of η e , χ c0 and χ c2 by including the full momentum dependence of the quark propagator. Comparing to the zero-order calculation the authors find that the finite-size vertex correction factor to the two-gluon decay widths of η c is 1.32, and for the two-gluon decays of χ c0 and χ c2 , the vertex correction factors are 1.45 and 1.26, respectively. With the corrected decay widths Γ(η c →2g) authors extract the value as α s (m c ) = 0.28 +- 0.05 which agrees with that calculated from the Γ(J/ψ→3g) process with the same correction. The finite-size vertex correction to the process Γ(η c →3g) is not as large as that to the process Γ(J/ψ→3g)

Temperature Dependence of Factors Controlling Isoprene Emissions

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

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

Three-dimensional photon dose distributions with and without lung corrections for tangential breast intact treatments

International Nuclear Information System (INIS)

Chin, L.M.; Cheng, C.W.; Siddon, R.L.; Rice, R.K.; Mijnheer, B.J.; Harris, J.R.

1989-01-01

The influence of lung volume and photon energy on the 3-dimensional dose distribution for patients treated by intact breast irradiation is not well established. To investigate this issue, we studied the 3-dimensional dose distributions calculated for an 'average' breast phantom for 60Co, 4 MV, 6 MV, and 8 MV photon beams. For the homogeneous breast, areas of high dose ('hot spots') lie along the periphery of the breast near the posterior plane and near the apex of the breast. The highest dose occurs at the inferior margin of the breast tissue, and this may exceed 125% of the target dose for lower photon energies. The magnitude of these 'hot spots' decreases for higher energy photons. When lung correction is included in the dose calculation, the doses to areas at the left and right margin of the lung volume increase. The magnitude of the increase depends on energy and the patient anatomy. For the 'average' breast phantom (lung density 0.31 g/cm3), the correction factors are between 1.03 to 1.06 depending on the energy used. Higher energy is associated with lower correction factors. Both the ratio-of-TMR and the Batho lung correction methods can predict these corrections within a few percent. The range of depths of the 100% isodose from the skin surface, measured along the perpendicular to the tangent of the skin surface, were also energy dependent. The range was 0.1-0.4 cm for 60Co and 0.5-1.4 cm for 8 MV. We conclude that the use of higher energy photons in the range used here provides lower value of the 'hot spots' compared to lower energy photons, but this needs to be balanced against a possible disadvantage in decreased dose delivered to the skin and superficial portion of the breast

A Systematic Analysis of Factors Localized to Damaged Chromatin Reveals PARP-Dependent Recruitment of Transcription Factors.

Science.gov (United States)

Izhar, Lior; Adamson, Britt; Ciccia, Alberto; Lewis, Jedd; Pontano-Vaites, Laura; Leng, Yumei; Liang, Anthony C; Westbrook, Thomas F; Harper, J Wade; Elledge, Stephen J

2015-06-09

Localization to sites of DNA damage is a hallmark of DNA damage response (DDR) proteins. To identify DDR factors, we screened epitope-tagged proteins for localization to sites of chromatin damaged by UV laser microirradiation and found >120 proteins that localize to damaged chromatin. These include the BAF tumor suppressor complex and the amyotrophic lateral sclerosis (ALS) candidate protein TAF15. TAF15 contains multiple domains that bind damaged chromatin in a poly-(ADP-ribose) polymerase (PARP)-dependent manner, suggesting a possible role as glue that tethers multiple PAR chains together. Many positives were transcription factors; > 70% of randomly tested transcription factors localized to sites of DNA damage, and of these, ∼90% were PARP dependent for localization. Mutational analyses showed that localization to damaged chromatin is DNA-binding-domain dependent. By examining Hoechst staining patterns at damage sites, we see evidence of chromatin decompaction that is PARP dependent. We propose that PARP-regulated chromatin remodeling at sites of damage allows transient accessibility of DNA-binding proteins. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

A Systematic Analysis of Factors Localized to Damaged Chromatin Reveals PARP-Dependent Recruitment of Transcription Factors

Directory of Open Access Journals (Sweden)

Lior Izhar

2015-06-01

Full Text Available Localization to sites of DNA damage is a hallmark of DNA damage response (DDR proteins. To identify DDR factors, we screened epitope-tagged proteins for localization to sites of chromatin damaged by UV laser microirradiation and found >120 proteins that localize to damaged chromatin. These include the BAF tumor suppressor complex and the amyotrophic lateral sclerosis (ALS candidate protein TAF15. TAF15 contains multiple domains that bind damaged chromatin in a poly-(ADP-ribose polymerase (PARP-dependent manner, suggesting a possible role as glue that tethers multiple PAR chains together. Many positives were transcription factors; > 70% of randomly tested transcription factors localized to sites of DNA damage, and of these, ∼90% were PARP dependent for localization. Mutational analyses showed that localization to damaged chromatin is DNA-binding-domain dependent. By examining Hoechst staining patterns at damage sites, we see evidence of chromatin decompaction that is PARP dependent. We propose that PARP-regulated chromatin remodeling at sites of damage allows transient accessibility of DNA-binding proteins.

Positional dependence of the SNPP VIIRS SD BRDF degradation factor

Science.gov (United States)

Lei, Ning; Chen, Xuexia; Chang, Tiejun; Xiong, Xiaoxiong

2017-09-01

The Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (SNPP) satellite is a passive scanning radiometer and an imager. The VIIRS regularly performs on-orbit radiometric calibration of its reflective solar bands (RSBs) through observing an onboard sunlit solar diffuser (SD). The reflectance of the SD changes over time and the change is denoted as the SD bidirectional reflectance distribution function degradation factor. The degradation factor, measured by an onboard solar diffuser stability monitor, has been shown to be both incident sunlight and outgoing direction dependent. In this Proceeding, we investigate the factor's dependence on SD position. We develop a model to relate the SD degradation factor with the amount of solar exposure. We use Earth measurements to evaluate the effectiveness of the model.

Saturation and Energy Corrections for TeV Electrons and Photons

CERN Document Server

Clerbaux, Barbara; Mahmoud, Tariq; Marage, Pierre Edouard

2006-01-01

This note presents a study of the response of the CMS electromagnetic calorimeter ECAL to high energy electrons and photons (from 500 to 4000 GeV), using the full simulation of the CMS detector. The longitudinal containment and the lateral extension of high energy showers are discussed, and energy and eta dependent correction factors F(E_meas, eta), where E_meas = E_ECAL + E_HCAL, are determined in order to reconstruct the incident particle energy, using the energies measured in the ECAL and in the hadronic calorimeter HCAL. For ECAL barrel crystals with energy deposit higher than 1700 GeV, improvements are proposed to techniques aimed at correcting for the effects of electronics saturation.

Smartphone dependence classification using tensor factorization

Science.gov (United States)

Kim, Yejin; Yook, In Hye; Yu, Hwanjo; Kim, Dai-Jin

2017-01-01

Excessive smartphone use causes personal and social problems. To address this issue, we sought to derive usage patterns that were directly correlated with smartphone dependence based on usage data. This study attempted to classify smartphone dependence using a data-driven prediction algorithm. We developed a mobile application to collect smartphone usage data. A total of 41,683 logs of 48 smartphone users were collected from March 8, 2015, to January 8, 2016. The participants were classified into the control group (SUC) or the addiction group (SUD) using the Korean Smartphone Addiction Proneness Scale for Adults (S-Scale) and a face-to-face offline interview by a psychiatrist and a clinical psychologist (SUC = 23 and SUD = 25). We derived usage patterns using tensor factorization and found the following six optimal usage patterns: 1) social networking services (SNS) during daytime, 2) web surfing, 3) SNS at night, 4) mobile shopping, 5) entertainment, and 6) gaming at night. The membership vectors of the six patterns obtained a significantly better prediction performance than the raw data. For all patterns, the usage times of the SUD were much longer than those of the SUC. From our findings, we concluded that usage patterns and membership vectors were effective tools to assess and predict smartphone dependence and could provide an intervention guideline to predict and treat smartphone dependence based on usage data. PMID:28636614

Smartphone dependence classification using tensor factorization.

Directory of Open Access Journals (Sweden)

Jingyun Choi

Full Text Available Excessive smartphone use causes personal and social problems. To address this issue, we sought to derive usage patterns that were directly correlated with smartphone dependence based on usage data. This study attempted to classify smartphone dependence using a data-driven prediction algorithm. We developed a mobile application to collect smartphone usage data. A total of 41,683 logs of 48 smartphone users were collected from March 8, 2015, to January 8, 2016. The participants were classified into the control group (SUC or the addiction group (SUD using the Korean Smartphone Addiction Proneness Scale for Adults (S-Scale and a face-to-face offline interview by a psychiatrist and a clinical psychologist (SUC = 23 and SUD = 25. We derived usage patterns using tensor factorization and found the following six optimal usage patterns: 1 social networking services (SNS during daytime, 2 web surfing, 3 SNS at night, 4 mobile shopping, 5 entertainment, and 6 gaming at night. The membership vectors of the six patterns obtained a significantly better prediction performance than the raw data. For all patterns, the usage times of the SUD were much longer than those of the SUC. From our findings, we concluded that usage patterns and membership vectors were effective tools to assess and predict smartphone dependence and could provide an intervention guideline to predict and treat smartphone dependence based on usage data.

Smartphone dependence classification using tensor factorization.

Science.gov (United States)

Choi, Jingyun; Rho, Mi Jung; Kim, Yejin; Yook, In Hye; Yu, Hwanjo; Kim, Dai-Jin; Choi, In Young

2017-01-01

Excessive smartphone use causes personal and social problems. To address this issue, we sought to derive usage patterns that were directly correlated with smartphone dependence based on usage data. This study attempted to classify smartphone dependence using a data-driven prediction algorithm. We developed a mobile application to collect smartphone usage data. A total of 41,683 logs of 48 smartphone users were collected from March 8, 2015, to January 8, 2016. The participants were classified into the control group (SUC) or the addiction group (SUD) using the Korean Smartphone Addiction Proneness Scale for Adults (S-Scale) and a face-to-face offline interview by a psychiatrist and a clinical psychologist (SUC = 23 and SUD = 25). We derived usage patterns using tensor factorization and found the following six optimal usage patterns: 1) social networking services (SNS) during daytime, 2) web surfing, 3) SNS at night, 4) mobile shopping, 5) entertainment, and 6) gaming at night. The membership vectors of the six patterns obtained a significantly better prediction performance than the raw data. For all patterns, the usage times of the SUD were much longer than those of the SUC. From our findings, we concluded that usage patterns and membership vectors were effective tools to assess and predict smartphone dependence and could provide an intervention guideline to predict and treat smartphone dependence based on usage data.

Perturbative corrections to Λ{sub b}→Λ form factors from QCD light-cone sum rules

Energy Technology Data Exchange (ETDEWEB)

Wang, Yu-Ming [Fakultät für Physik, Universität Wien,Boltzmanngasse 5, 1090 Vienna (Austria); Physik Department T31, Technische Universität München,James-Franck-Straße 1, D-85748 Garching (Germany); Shen, Yue-Long [College of Information Science and Engineering, Ocean University of China,Songling Road 238, Qingdao, Shandong 266100 (China)

2016-02-29

We compute radiative corrections to Λ{sub b}→Λ from factors, at next-to-leading logarithmic accuracy, from QCD light-cone sum rules with Λ{sub b}-baryon distribution amplitudes. Employing the diagrammatic approach factorization of the vacuum-to-Λ{sub b}-baryon correlation function is justified at leading power in Λ/m{sub 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{sub s}) shift the Λ{sub 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{sub b}→Λ from factors we further investigate several decay observables in the electro-weak penguin Λ{sub b}→Λ ℓ{sup +}ℓ{sup −} transitions in the factorization limit (i.e., ignoring the “non-factorizable' hadronic effects which cannot be expressed in terms of the Λ{sub 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.

An analytical inductor design procedure for three-phase PWM converters in power factor correction applications

DEFF Research Database (Denmark)

Kouchaki, Alireza; Niroumand, Farideh Javidi; Haase, Frerk

2015-01-01

This paper presents an analytical method for designing the inductor of three-phase power factor correction converters (PFCs). The complex behavior of the inductor current complicates the inductor design procedure as well as the core loss and copper loss calculations. Therefore, this paper analyze...... to calculate the core loss in the PFC application. To investigate the impact of the dc link voltage level, two inductors for different dc voltage levels are designed and the results are compared.......This paper presents an analytical method for designing the inductor of three-phase power factor correction converters (PFCs). The complex behavior of the inductor current complicates the inductor design procedure as well as the core loss and copper loss calculations. Therefore, this paper analyzes...... circuit is used to provide the inductor current harmonic spectrum. Therefore, using the harmonic spectrum, the low and high frequency copper losses are calculated. The high frequency minor B-H loops in one switching cycle are also analyzed. Then, the loss map provided by the measurement setup is used...

Correction factor to determine total hydrogen+deuterium concentration obtained by inert gas fusion-thermal conductivity detection (IGF- TCD) technique

International Nuclear Information System (INIS)

Ramakumar, K.L.; Sesha Sayi, Y.; Shankaran, P.S.; Chhapru, G.C; Yadav, C.S.; Venugopal, V.

2004-01-01

The limitation of commercially available dedicated equipment based on Inert Gas Fusion- Thermal Conductivity Detection (IGF - TCD) for the determination of hydrogen+deuterium is described. For a given molar concentration, deuterium is underestimated vis a vis hydrogen because of lower thermal conductivity and not considering its molecular weight in calculations. An empirical correction factor based on the differences between the thermal conductivities of hydrogen, deuterium and the carrier gas argon, and the mole fraction of deuterium in the sample has been derived to correct the observed hydrogen+deuterium concentration. The corrected results obtained by IGF - TCD technique have been validated by determining hydrogen and deuterium contents in a few samples using an independent method based on hot vacuum extraction-quadrupole mass spectrometry (HVE-QMS). Knowledge of mole fraction of deuterium (XD) is necessary to effect the correction. The correction becomes insignificant at low X D values (XD < 0.2) as the precision in the IGF measurements is comparable with the extent of correction. (author)

Quantum Critical Scaling and Temperature-Dependent Logarithmic Corrections in the Spin-Half Heisenberg Chain

International Nuclear Information System (INIS)

Starykh, O.; Singh, R.; Sandvik, A.

1997-01-01

Low temperature dynamics of the S=(1)/(2) Heisenberg chain is studied via a simple ansatz generalizing the conformal mapping and analytic continuation procedures to correlation functions with multiplicative logarithmic factors. Closed form expressions for the dynamic susceptibility and the NMR relaxation rates 1/T 1 and 1/T 2G are obtained, and are argued to improve the agreement with recent experiments. Scaling in q/T and ω/T are violated due to these logarithmic terms. Numerical results show that the logarithmic corrections are very robust. While not yet in the asymptotic low temperature regime, they provide striking qualitative confirmation of the theoretical results. copyright 1997 The American Physical Society

Precise method for correcting count-rate losses in scintillation cameras

International Nuclear Information System (INIS)

Madsen, M.T.; Nickles, R.J.

1986-01-01

Quantitative studies performed with scintillation detectors often require corrections for lost data because of the finite resolving time of the detector. Methods that monitor losses by means of a reference source or pulser have unacceptably large statistical fluctuations associated with their correction factors. Analytic methods that model the detector as a paralyzable system require an accurate estimate of the system resolving time. Because the apparent resolving time depends on many variables, including the window setting, source distribution, and the amount of scattering material, significant errors can be introduced by relying on a resolving time obtained from phantom measurements. These problems can be overcome by curve-fitting the data from a reference source to a paralyzable model in which the true total count rate in the selected window is estimated from the observed total rate. The resolving time becomes a free parameter in this method which is optimized to provide the best fit to the observed reference data. The fitted curve has the inherent accuracy of the reference source method with the precision associated with the observed total image count rate. Correction factors can be simply calculated from the ratio of the true reference source rate and the fitted curve. As a result, the statistical uncertainty of the data corrected by this method is not significantly increased

Correcting human heart 31P NMR spectra for partial saturation. Evidence that saturation factors for PCr/ATP are homogeneous in normal and disease states

Science.gov (United States)

Bottomley, Paul A.; Hardy, Christopher J.; Weiss, Robert G.

Heart PCr/ATP ratios measured from spatially localized 31P NMR spectra can be corrected for partial saturation effects using saturation factors derived from unlocalized chest surface-coil spectra acquired at the heart rate and approximate Ernst angle for phosphor creatine (PCr) and again under fully relaxed conditions during each 31P exam. To validate this approach in studies of normal and disease states where the possibility of heterogeneity in metabolite T1 values between both chest muscle and heart and normal and disease states exists, the properties of saturation factors for metabolite ratios were investigated theoretically under conditions applicable in typical cardiac spectroscopy exams and empirically using data from 82 cardiac 31P exams in six study groups comprising normal controls ( n = 19) and patients with dilated ( n = 20) and hypertrophic ( n = 5) cardiomyopathy, coronary artery disease ( n = 16), heart transplants ( n = 19), and valvular heart disease ( n = 3). When TR ≪ T1,(PCr), with T1(PCr) ⩾ T1(ATP), the saturation factor for PCr/ATP lies in the range 1.5 ± 0.5, regardless of the T1 values. The precise value depends on the ratio of metabolite T1 values rather than their absolute values and is insensitive to modest changes in TR. Published data suggest that the metabolite T1 ratio is the same in heart and muscle. Our empirical data reveal that the saturation factors do not vary significantly with disease state, nor with the relative fractions of muscle and heart contributing to the chest surface-coil spectra. Also, the corrected myocardial PCr/ATP ratios in each normal or disease state bear no correlation with the corresponding saturation factors nor the fraction of muscle in the unlocalized chest spectra. However, application of the saturation correction (mean value, 1.36 ± 0.03 SE) significantly reduced scatter in myocardial PCr/ATP data by 14 ± 11% (SD) ( p ⩽ 0.05). The findings suggest that the relative T1 values of PCr and ATP are

A method for determining an effective porosity correction factor for thermal conductivity in fast reactor uranium-plutonium oxide fuel pellets

International Nuclear Information System (INIS)

Inoue, Masaki; Abe, Kazuyuki; Sato, Isamu

2000-01-01

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 μm 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

The Temperature Dependence of the Debye-Waller Factor of Magnesium

DEFF Research Database (Denmark)

Sledziewska-Blocka, D.; Lebech, Bente

1976-01-01

The temperature dependence of the average Debye-Waller factor for magnesium was measured by means of neutron diffraction spectrometry. The experimental results obtained in the temperature range from 5 to 256 K are compared with theoretical calculations, using the harmonic and quasi-harmonic appro......The temperature dependence of the average Debye-Waller factor for magnesium was measured by means of neutron diffraction spectrometry. The experimental results obtained in the temperature range from 5 to 256 K are compared with theoretical calculations, using the harmonic and quasi......-harmonic approximations and results of previous experiments....

Scheme and scale dependences of leading electroweak corrections

International Nuclear Information System (INIS)

Kniehl, B.A.; Sirlin, A.

1996-01-01

The scheme and scale dependences of leading M t -dependent contributions to Δρ, Δr, and τ, which arise because of the truncation of the perturbative series, are investigated by comparing expressions in the on-shell and MS schemes of renormalization, and studying their scale variations. Starting from the conventional on-shell formulae, we find rather large scheme and scale dependences. We then propose a simple, physically motivated modification of the conventional expressions and show that it leads to a sharp reduction in the scheme and scale dependences. Implications for electroweak physics are discussed. (orig.)

Development of a correction factor for Xe-133 vials for use with a dose calibrator

International Nuclear Information System (INIS)

Gels, G.L.; Piltingsrud, H.V.

1982-01-01

Manufacturers of dose calibrators who give calibration settings for various radionuclies sometimes do not specify the type of radionuclide container the calibration is for. The container, moreover, may not be of the same type as those a user might purchase. When these factors are not considered, the activity administered to the patient may be significantly different from that intended. An experiment is described in which calibration factors are determined for measurement of Xe-133 activity in vials in a dose calibrator. This was accomplished by transferring the Xe-133 from the commercial vials to standard NBS calibration ampules. Based on ten such transfers, the resulting correction factor for the dose calibrator was 1.22

Path dependence in social and psychological risk factors for dementia

Directory of Open Access Journals (Sweden)

Hiroko Matsuoka

Full Text Available Abstract This article focuses on social and psychological risk factors for Alzheimer's disease, dementia, and cognitive impairment and presents some key points for prevention in developing countries based on previous studies, a social science theory, and our preliminary survey. Previous population-based studies found that educational and occupational attainment, income, participation in social and mental activities, and psychological distress were associated with dementia risk. According to the theory of path dependence, earlier factors largely determine successive ones, where education is one of these early experiences in life. Our preliminary survey suggested that education sets a path that several psychosocial risk factors are dependent on. The expansion of basic education is indispensable. Resources for prevention should be concentrated on individuals with a low level of education. In order to break from a path creating self-reinforcement of risk factors, it is necessary to implement early and active interventions.

CTE Corrections for WFPC2 and ACS

Science.gov (United States)

Dolphin, Andrew

2003-07-01

The error budget for optical broadband photometry is dominated by three factors: CTE corrections, long-short anomaly corrections, and photometric zero points. Questions about the dependencies of the CTE have largely been resolved, and my CTE corrections have been included in the WFPC2 handbook and tutorial. What remains to be done is the determination of the "final" CTE correction at the end of the WFPC2 mission, which will increase the accuracy of photometry obtained in the final few cycles. The long-short anomaly is still the subject of much debate, as it remains unclear whethere or not this effect is real and, if so, what its size and nature is. Photometric zero points have likewise varied by over 0.05 magnitudes in the literature, and will likely remain unresolved until the long-short anomaly is addressed {given that most calibration exposures are short while most science exposures are long}. It is also becoming apparent that similar issues will affect the accuracy of ACS photometry, and consequently that an ACS CTE study analogous to my WFPC2 work would significantly improve the calibration of ACS. I therefore propose to use archival WFPC2 images of omega Cen and ACS images of 47 Tuc to continue my HST calibration work. I also propose to begin work on "next-generation" CTE corrections, in which corrections are applied to the images based on accurate charge-trapping models rather than to the reduced photometry. This technique will allow for more accurate CTE corrections in certain cases {such as a star above a bright star or on a variable background}, improved PSF-fitting photometry of faint stars, and image restoration for accurate analysis of extended objects.

High Efficiency Three-phase Power Factor Correction Rectifier using Wide Band-Gap Devices

DEFF Research Database (Denmark)

Kouchaki, Alireza

Improving the conversion efficiency of power factor correction (PFC) rectifiers has become compelling due to their wide applications such as adjustable speed drives, uninterruptible power supplies (UPS), and battery chargers for electric vehicles (EVs). The attention to PFCs has increased even more....... Therefore, current controllers are also important to be investigated in this project. In this PhD research work, a comprehensive design of a two-level three-phase PFC rectifier using silicon-carbide (SiC) switches to achieve high efficiency is presented. The work is divided into two main parts: 1) Optimum...

Three-loop massive form factors: complete light-fermion corrections for the vector current

Science.gov (United States)

Lee, Roman N.; Smirnov, Alexander V.; Smirnov, Vladimir A.; Steinhauser, Matthias

2018-03-01

We compute the three-loop QCD corrections to the massive quark-anti-quark-photon form factors F 1 and F 2 involving a closed loop of massless fermions. This subset is gauge invariant and contains both planar and non-planar contributions. We perform the reduction using FIRE and compute the master integrals with the help of differential equations. Our analytic results can be expressed in terms of Goncharov polylogarithms. We provide analytic results for all master integrals which are not present in the large- N c calculation considered in refs. [1, 2].

Thermal nucleation of kink-antikink pairs in a deformable chain: Influence of the non-Gaussian correction

International Nuclear Information System (INIS)

Woulache, R.L.; Kofane, T.C.; Yemele, D.

2005-08-01

Thermal nucleation of kink-antikink pairs in a nonlinear Klein- Gordon model with Remoissenet-Peyrard substrate potential coupled to an applied field is analyzed in the limits of moderate temperature and strong damping. We derive analytically the non- Gaussian correction to the nucleation rate formula of kink- antikink pairs previously calculated by Yemele and Kofane and show that the correction factor depends on the intensity of the applied field, the temperature of the system and the shape of the substrate potential. (author)

Real-Gas Correction Factors for Hypersonic Flow Parameters in Helium

Science.gov (United States)

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.

[Factors associated with involuntary hospital admissions in technology-dependent children].

Science.gov (United States)

Okido, Aline Cristiane Cavicchioli; Pina, Juliana Coelho; Lima, Regina Aparecida Garcia

2016-02-01

To identify the factors associated with involuntary hospital admissions of technology-dependent children, in the municipality of Ribeirão Preto, São Paulo State, Brazil. A cross-sectional study, with a quantitative approach. After an active search, 124 children who qualified under the inclusion criteria, that is to say, children from birth to age 12, were identified. Data was collected in home visits to mothers or the people responsible for the children, through the application of a questionnaire. Analysis of the data followed the assumptions of the Generalized Linear Models technique. 102 technology-dependent children aged between 6 months and 12 years participated in the study, of whom 57% were male. The average number of involuntary hospital admissions in the previous year among the children studied was 0.71 (±1.29). In the final model the following variables were significantly associated with the outcome: age (OR=0.991; CI95%=0.985-0.997), and the number of devices (OR=0.387; CI95%=0.219-0.684), which were characterized as factors of protection and quantity of medications (OR=1.532; CI95%=1.297-1.810), representing a risk factor for involuntary hospital admissions in technology-dependent children. The results constitute input data for consideration of the process of care for technology-dependent children by supplying an explanatory model for involuntary hospital admissions for this client group.

An analytical evaluation for spatial-dependent intra-pebble Dancoff factor and escape probability

International Nuclear Information System (INIS)

Kim, Songhyun; Kim, Hong-Chul; Kim, Jong Kyung; Kim, Soon Young; Noh, Jae Man

2009-01-01

The analytical evaluation of spatial-dependent intra-pebble Dancoff factors and their escape probabilities is pursued by the model developed in this study. Intra-pebble Dancoff factors and their escape probabilities are calculated as a function of fuel kernel radius, number of fuel kernels, and fuel region radius. The method in this study can be easily utilized to analyze the tendency of spatial-dependent intra-pebble Dancoff factor and spatial-dependent fuel region escape probability for the various geometries because it is faster than the MCNP method as well as good accuracy. (author)

Process evaluation of two participatory approaches: Implementing total worker health® interventions in a correctional workforce.

Science.gov (United States)

Dugan, Alicia G; Farr, Dana A; Namazi, Sara; Henning, Robert A; Wallace, Kelly N; El Ghaziri, Mazen; Punnett, Laura; Dussetschleger, Jeffrey L; Cherniack, Martin G

2016-10-01

Correctional Officers (COs) have among the highest injury rates and poorest health of all the public safety occupations. The HITEC-2 (Health Improvement Through Employee Control-2) study uses Participatory Action Research (PAR) to design and implement interventions to improve health and safety of COs. HITEC-2 compared two different types of participatory program, a CO-only "Design Team" (DT) and "Kaizen Event Teams" (KET) of COs and supervisors, to determine differences in implementation process and outcomes. The Program Evaluation Rating Sheet (PERS) was developed to document and evaluate program implementation. Both programs yielded successful and unsuccessful interventions, dependent upon team-, facility-, organizational, state-, facilitator-, and intervention-level factors. PAR in corrections, and possibly other sectors, depends upon factors including participation, leadership, continuity and timing, resilience, and financial circumstances. The new PERS instrument may be useful in other sectors to assist in assessing intervention success. Am. J. Ind. Med. 59:897-918, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Process Evaluation of Two Participatory Approaches: Implementing Total Worker Health® Interventions in a Correctional Workforce

Science.gov (United States)

Dugan, Alicia G.; Farr, Dana A.; Namazi, Sara; Henning, Robert A.; Wallace, Kelly N.; El Ghaziri, Mazen; Punnett, Laura; Dussetschleger, Jeffrey L.; Cherniack, Martin G.

2018-01-01

Background Correctional Officers (COs) have among the highest injury rates and poorest health of all the public safety occupations. The HITEC-2 (Health Improvement Through Employee Control-2) study uses Participatory Action Research (PAR) to design and implement interventions to improve health and safety of COs. Method HITEC-2 compared two different types of participatory program, a CO-only “Design Team” (DT) and “Kaizen Event Teams” (KET) of COs and supervisors, to determine differences in implementation process and outcomes. The Program Evaluation Rating Sheet (PERS) was developed to document and evaluate program implementation. Results Both programs yielded successful and unsuccessful interventions, dependent upon team-, facility-, organizational, state-, facilitator-, and intervention-level factors. Conclusions PAR in corrections, and possibly other sectors, depends upon factors including participation, leadership, continuity and timing, resilience, and financial circumstances. The new PERS instrument may be useful in other sectors to assist in assessing intervention success. PMID:27378470

Temperature dependence of plastic scintillators

Science.gov (United States)

Peralta, L.

2018-03-01

Plastic scintillator detectors have been studied as dosimeters, since they provide a cost-effective alternative to conventional ionization chambers. Several articles have reported undesired response dependencies on beam energy and temperature, which provides the motivation to determine appropriate correction factors. In this work, we studied the light yield temperature dependency of four plastic scintillators, BCF-10, BCF-60, BC-404, RP-200A and two clear fibers, BCF-98 and SK-80. Measurements were made using a 50 kVp X-ray beam to produce the scintillation and/or radioluminescence signal. The 0 to 40 °C temperature range was scanned for each scintillator, and temperature coefficients were obtained.

Measured attenuation correction methods

International Nuclear Information System (INIS)

Ostertag, H.; Kuebler, W.K.; Doll, J.; Lorenz, W.J.

1989-01-01

Accurate attenuation correction is a prerequisite for the determination of exact local radioactivity concentrations in positron emission tomography. Attenuation correction factors range from 4-5 in brain studies to 50-100 in whole body measurements. This report gives an overview of the different methods of determining the attenuation correction factors by transmission measurements using an external positron emitting source. The long-lived generator nuclide 68 Ge/ 68 Ga is commonly used for this purpose. The additional patient dose from the transmission source is usually a small fraction of the dose due to the subsequent emission measurement. Ring-shaped transmission sources as well as rotating point or line sources are employed in modern positron tomographs. By masking a rotating line or point source, random and scattered events in the transmission scans can be effectively suppressed. The problems of measured attenuation correction are discussed: Transmission/emission mismatch, random and scattered event contamination, counting statistics, transmission/emission scatter compensation, transmission scan after administration of activity to the patient. By using a double masking technique simultaneous emission and transmission scans become feasible. (orig.)

Correction of gene expression data: Performance-dependency on inter-replicate and inter-treatment biases.

Science.gov (United States)

Darbani, Behrooz; Stewart, C Neal; Noeparvar, Shahin; Borg, Søren

2014-10-20

This report investigates for the first time the potential inter-treatment bias source of cell number for gene expression studies. Cell-number bias can affect gene expression analysis when comparing samples with unequal total cellular RNA content or with different RNA extraction efficiencies. For maximal reliability of analysis, therefore, comparisons should be performed at the cellular level. This could be accomplished using an appropriate correction method that can detect and remove the inter-treatment bias for cell-number. Based on inter-treatment variations of reference genes, we introduce an analytical approach to examine the suitability of correction methods by considering the inter-treatment bias as well as the inter-replicate variance, which allows use of the best correction method with minimum residual bias. Analyses of RNA sequencing and microarray data showed that the efficiencies of correction methods are influenced by the inter-treatment bias as well as the inter-replicate variance. Therefore, we recommend inspecting both of the bias sources in order to apply the most efficient correction method. As an alternative correction strategy, sequential application of different correction approaches is also advised. Copyright © 2014 Elsevier B.V. All rights reserved.

Risk of alcohol dependence: prevalence, related problems and socioeconomic factors

Directory of Open Access Journals (Sweden)

Juliana Gabrielle Martins-Oliveira

2016-01-01

Full Text Available Abstract The present study evaluated the possible alcohol dependence and related problems among adolescents and determined possible associations with socioeconomic factors and gender. A cross-sectional study was conducted with a representative sample of 936 adolescents aged 15 to 19 years enrolled at public and private schools in the city of Belo Horizonte, Brazil. Data related to alcohol consumption and associated problems were collected using the Alcohol Use Disorder Identification Test (AUDIT. The Social Vulnerability Index (SVI, mother's schooling and type of school were used to assess socioeconomic factors. Statistical analysis involved the chi-square test (p < 0.05 and Poisson regression. The prevalence of possible dependence was 16.4%, 52.1% reported concern of a family member regarding the adolescent's alcohol consumption. Female adolescents were less likely to exhibit possible dependence in comparison to males. Participants with living in a low vulnerability area were more likely to consume alcohol in comparison to those living in underprivileged areas. The results of the present study demonstrate that possible dependence was significantly associated with the male gender and low social vulnerability.

Core-dependent and ligand-dependent relativistic corrections to the nuclear magnetic shieldings in MH4-n Y n (n = 0-4; M = Si, Ge, Sn, and Y = H, F, Cl, Br, I) model compounds.

Science.gov (United States)

Maldonado, Alejandro F; Aucar, Gustavo A; Melo, Juan I

2014-09-01

The nuclear magnetic shieldings of Si, Ge, and Sn in MH(4-n) Y(n) (M = Si, Ge, Sn; Y = F, Cl, Br, I and n = 1-4) molecular systems are highly influenced by the substitution of one or more hydrogens by heavy-halogen atoms. We applied the linear response elimination of small components (LRESC) formalism to calculate those shieldings and learn whether including only a few of the leading relativistic correction terms is sufficient to be able to quantitatively reproduce the full relativistic value. It was observed that the nuclear magnetic shieldings change as the number of heavy halogen substituents and their weights vary, and the pattern of σ(M) generally does not exhibit the normal halogen dependence (NHD) behavior that can be seen in similar molecular systems containing carbon atoms. We also analyzed each relativistic correction afforded by the LRESC method and split them in two: core-dependent and ligand-dependent contributions; we then looked for the electronic mechanisms involved in the different relativistic effects and in the total relativistic value. Based on this analysis, we were able to study the electronic mechanism involved in a recently proposed relativistic effect, the "heavy atom effect on vicinal heavy atom" (HAVHA), in more detail. We found that the main electronic mechanism is the spin-orbit or σ p (T(3)) correction, although other corrections such as σ p (S(1)) and σ p (S(3)) are also important. Finally, we analyzed proton magnetic shieldings and found that, for molecules containing Sn as the central atom, σ(H) decreases as the number of heavy halogen substituents (of the same type: either F, Cl, or Br) increases, albeit at different rates for different halogens. σ(H) only increase as the number of halogen substituents increases if the halogen is iodine.

Generalized Efficient Inference on Factor Models with Long-Range Dependence

DEFF Research Database (Denmark)

Ergemen, Yunus Emre

. Short-memory dynamics are allowed in the common factor structure and possibly heteroskedastic error term. In the estimation, a generalized version of the principal components (PC) approach is proposed to achieve efficiency. Asymptotics for efficient common factor and factor loading as well as long......A dynamic factor model is considered that contains stochastic time trends allowing for stationary and nonstationary long-range dependence. The model nests standard I(0) and I(1) behaviour smoothly in common factors and residuals, removing the necessity of a priori unit-root and stationarity testing...

Social factors and readmission after inpatient detoxification in older alcohol-dependent patients

NARCIS (Netherlands)

van den Berg, Julia F.; van den Brink, Wim; Kist, Nicolien; Hermes, Jolanda S. J.; Kok, Rob M.

2015-01-01

Alcohol dependence is often a chronic relapsing disorder with frequent admissions to inpatient facilities. This study in older alcohol-dependent inpatients investigates the role of social factors in readmissions after inpatient detoxification. In a prospective study, 132 older alcohol-dependent

Calculation of the Energy Dependence of Dosimeter Response to Ionizing Photons

DEFF Research Database (Denmark)

Miller, Arne; McLaughlin, W. L.

1982-01-01

Using a program in BASIC applied to a desk-top calculator, simplified calculations provide approximate energy dependence correction factors of dosimeter readings of absorbed dose according to Bragg-Gray cavity theories. Burlin's general cavity theory is applied in the present calculations, and ce...

Ratio-based vs. model-based methods to correct for urinary creatinine concentrations.

Science.gov (United States)

Jain, Ram B

2016-08-01

Creatinine-corrected urinary analyte concentration is usually computed as the ratio of the observed level of analyte concentration divided by the observed level of the urinary creatinine concentration (UCR). This ratio-based method is flawed since it implicitly assumes that hydration is the only factor that affects urinary creatinine concentrations. On the contrary, it has been shown in the literature, that age, gender, race/ethnicity, and other factors also affect UCR. Consequently, an optimal method to correct for UCR should correct for hydration as well as other factors like age, gender, and race/ethnicity that affect UCR. Model-based creatinine correction in which observed UCRs are used as an independent variable in regression models has been proposed. This study was conducted to evaluate the performance of ratio-based and model-based creatinine correction methods when the effects of gender, age, and race/ethnicity are evaluated one factor at a time for selected urinary analytes and metabolites. It was observed that ratio-based method leads to statistically significant pairwise differences, for example, between males and females or between non-Hispanic whites (NHW) and non-Hispanic blacks (NHB), more often than the model-based method. However, depending upon the analyte of interest, the reverse is also possible. The estimated ratios of geometric means (GM), for example, male to female or NHW to NHB, were also compared for the two methods. When estimated UCRs were higher for the group (for example, males) in the numerator of this ratio, these ratios were higher for the model-based method, for example, male to female ratio of GMs. When estimated UCR were lower for the group (for example, NHW) in the numerator of this ratio, these ratios were higher for the ratio-based method, for example, NHW to NHB ratio of GMs. Model-based method is the method of choice if all factors that affect UCR are to be accounted for.

Radiative corrections to neutrino deep inelastic scattering revisited

International Nuclear Information System (INIS)

Arbuzov, Andrej B.; Bardin, Dmitry Yu.; Kalinovskaya, Lidia V.

2005-01-01

Radiative corrections to neutrino deep inelastic scattering are revisited. One-loop electroweak corrections are re-calculated within the automatic SANC system. Terms with mass singularities are treated including higher order leading logarithmic corrections. Scheme dependence of corrections due to weak interactions is investigated. The results are implemented into the data analysis of the NOMAD experiment. The present theoretical accuracy in description of the process is discussed

Energy dependence of the zero-range DWBA normalization of the /sup 58/Ni(/sup 3/He,. cap alpha. )/sup 57/Ni reaction. [15 to 205 GeV, finite-range and nonlocality corrections

Energy Technology Data Exchange (ETDEWEB)

Shepard, J R; Zimmerman, W R; Kraushaar, J J [Colorado Univ., Boulder (USA). Dept. of Physics and Astrophysics

1977-01-04

Strong transitions in the /sup 58/Ni(/sup 3/He,..cap alpha..)/sup 57/Ni reaction were analyzed using both the zero-range and exact finite-range DWBA. Data considered covered a range of bombarding energies from 15 to 205 MeV. The zero-range DWBA described all data well when finite-range and non-locality corrections were included in the local energy approximation. Comparison of zero-range and exact finite-range calculations showed the local energy approximation correction to be very accurate over the entire energy region. Empirically determined D/sub 0/ values showed no energy dependence. A theoretical D/sub 0/ value calculated using an ..cap alpha.. wave function which reproduced the measured ..cap alpha.. rms charge radius and the elastic electron scattering form factor agreed well the empirical values. Comparison was made between these values and D/sub 0/ values quoted previously in the literature.

Color correction optimization with hue regularization

Science.gov (United States)

Zhang, Heng; Liu, Huaping; Quan, Shuxue

2011-01-01

Previous work has suggested that observers are capable of judging the quality of an image without any knowledge of the original scene. When no reference is available, observers can extract the apparent objects in an image and compare them with the typical colors of similar objects recalled from their memories. Some generally agreed upon research results indicate that although perfect colorimetric rendering is not conspicuous and color errors can be well tolerated, the appropriate rendition of certain memory colors such as skin, grass, and sky is an important factor in the overall perceived image quality. These colors are appreciated in a fairly consistent manner and are memorized with slightly different hues and higher color saturation. The aim of color correction for a digital color pipeline is to transform the image data from a device dependent color space to a target color space, usually through a color correction matrix which in its most basic form is optimized through linear regressions between the two sets of data in two color spaces in the sense of minimized Euclidean color error. Unfortunately, this method could result in objectionable distortions if the color error biased certain colors undesirably. In this paper, we propose a color correction optimization method with preferred color reproduction in mind through hue regularization and present some experimental results.

Planar imaging quantification using 3D attenuation correction data and Monte Carlo simulated buildup factors

International Nuclear Information System (INIS)

Miller, C.; Filipow, L.; Jackson, S.; Riauka, T.

1996-01-01

A new method to correct for attenuation and the buildup of scatter in planar imaging quantification is presented. The method is based on the combined use of 3D density information provided by computed tomography to correct for attenuation and the application of Monte Carlo simulated buildup factors to correct for buildup in the projection pixels. CT and nuclear medicine images were obtained for a purpose-built nonhomogeneous phantom that models the human anatomy in the thoracic and abdominal regions. The CT transverse slices of the phantom were converted to a set of consecutive density maps. An algorithm was developed that projects the 3D information contained in the set of density maps to create opposing pairs of accurate 2D correction maps that were subsequently applied to planar images acquired from a dual-head gamma camera. A comparison of results obtained by the new method and the geometric mean approach based on published techniques is presented for some of the source arrangements used. Excellent results were obtained for various source - phantom configurations used to evaluate the method. Activity quantification of a line source at most locations in the nonhomogeneous phantom produced errors of less than 2%. Additionally, knowledge of the actual source depth is not required for accurate activity quantification. Quantification of volume sources placed in foam, Perspex and aluminium produced errors of less than 7% for the abdominal and thoracic configurations of the phantom. (author)

Detection unit with corrected energy dependence

International Nuclear Information System (INIS)

Viererbl, L.

1989-01-01

The detection unit consists of a plastic scintillator with a layer of a powder semicrystalline scintillator deposited on its surface. An inorgaic monocrystalline scintillator is placed inside the plastic scintillator and surrounded with an absorption layer, except for the window. The advantage of the detection unit is a reduced energy dependence of response, especially in the energy range 100 to 400 keV. (E.J.). 3 figs

Heavy meson form factors from QCD

International Nuclear Information System (INIS)

Falk, A.F.; Georgi, H.; Grinstein, B.

1990-01-01

We calculate the leading QCD radiative corrections to the relations which follow from the decoupling of the heavy quark spin as the quark mass goes infinity and from the symmetry between systems with different heavy quarks. One of the effects we calculate gives the leading q 2 -dependence of the form factor of a heavy quark, which in turn dominates the q 2 -dependence of the form factors of bound states of the heavy quark with light quarks. This, combined with the normalization of the form factor provided by symmetry, gives us a first principles calculation of the heavy meson (or baryon) form factors in the limit of very large heavy quark mass. (orig.)

Determination of the Kwall correction factor for a cylindrical ionization chamber to measure air-kerma in 60Co gamma beams

International Nuclear Information System (INIS)

Laitano, R.F.; Toni, M.P.; Pimpinella, M.; Bovi, M.

2002-01-01

The factor K wall to correct for photon attenuation and scatter in the wall of ionization chambers for 60 Co air-kerma measurement has been traditionally determined by a procedure based on a linear extrapolation of the chamber current to zero wall thickness. Monte Carlo calculations by Rogers and Bielajew (1990 Phys. Med. Biol. 35 1065-78) provided evidence, mostly for chambers of cylindrical and spherical geometry, of appreciable deviations between the calculated values of K wall and those obtained by the traditional extrapolation procedure. In the present work an experimental method other than the traditional extrapolation procedure was used to determine the K wall factor. In this method the dependence of the ionization current in a cylindrical chamber was analysed as a function of an effective wall thickness in place of the physical (radial) wall thickness traditionally considered in this type of measurement. To this end the chamber wall was ideally divided into distinct regions and for each region an effective thickness to which the chamber current correlates was determined. A Monte Carlo calculation of attenuation and scatter effects in the different regions of the chamber wall was also made to compare calculation to measurement results. The K wall values experimentally determined in this work agree within 0.2% with the Monte Carlo calculation. The agreement between these independent methods and the appreciable deviation (up to about 1%) between the results of both these methods and those obtained by the traditional extrapolation procedure support the conclusion that the two independent methods providing comparable results are correct and the traditional extrapolation procedure is likely to be wrong. The numerical results of the present study refer to a cylindrical cavity chamber like that adopted as the Italian national air-kerma standard at INMRI-ENEA (Italy). The method used in this study applies, however, to any other chamber of the same type. (author)

Theoretical foundations of the correction factors for the analysis of the relative variations of 13C/12C and 18O/16O ratios, by mass spectrometry

International Nuclear Information System (INIS)

Ducatti, C.; Salati, E.

1982-01-01

A review is made of analytical procedures to calculate correction factors, proposed by CRAIG (1957) to determine isotopic enrichment relating to the international PBD standard sample, obtained from analysis of carbon dioxide gas samples by mass spectrometry. Using such correction factors, the isotopic composition of the secondary CENA-standard sample is characterized through calculation of the main isotopic ratios of this sample. It is then possible to obtain correction factors for the determination of the isotopic enrichment relating to the secondary CENA-standard sample itself. New correction factors are proposed taking into account the interference of various isotopic species and the variability in sample and secondary standard preparation, that make possible the detemination of carbon-13 and oxygen-18 isotopic enrichment relating to the international PBD standard sample, with a total analytical error σ = + - 0.2 0 /00 in normal routine work. (Author) [pt

Retroviral restriction and dependency factors in primates and carnivores

Science.gov (United States)

Fadel, Hind J.; Poeschla, Eric M.

2014-01-01

Recent studies have extended the rapidly developing retroviral restriction factor field to cells of carnivore species. Carnivoran genomes, and the domestic cat genome in particular, are revealing intriguing properties vis-à;-vis the primate and feline lentiviruses, not only with respect to their repertoires of virus-blocking restriction factors but also replication-enabling dependency factors. Therapeutic application of restriction factors is envisioned for human immunodeficiency virus (HIV) disease and the feline immunodeficiency virus (FIV) model has promise for testing important hypotheses at the basic and translational level. Feline cell-tropic HIV-1 clones have also been generated by a strategy of restriction factor evasion. We review progress in this area in the context of what is known about retroviral restriction factors such as TRIM5alpha, TRIMCyp, APOBEC3 proteins and BST-2/Tetherin. PMID:21715018

Reliability Analysis of Offshore Jacket Structures with Wave Load on Deck using the Model Correction Factor Method

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard; Friis-Hansen, P.; Nielsen, J.S.

2006-01-01

failure/collapse of jacket type platforms with wave in deck loads using the so-called Model Correction Factor Method (MCFM). A simple representative model for the RSR measure is developed and used in the MCFM technique. A realistic example is evaluated and it is seen that it is possible to perform...

Higher order QCD corrections in small x physics

International Nuclear Information System (INIS)

Chachamis, G.

2006-11-01

We study higher order QCD corrections in small x Physics. The numerical implementation of the full NLO photon impact factor is the remaining necessary piece for the testing of the NLO BFKL resummation against data from physical processes, such as γ * γ * collisions. We perform the numerical integration over phase space for the virtual corrections to the NLO photon impact factor. This, along with the previously calculated real corrections, makes feasible in the near future first estimates for the γ*γ* total cross section, since the convolution of the full impact factor with the NLO BFKL gluon Green's function is now straightforward. The NLO corrections for the photon impact factor are sizeable and negative. In the second part of this thesis, we estimate higher order correction to the BK equation. We are mainly interested in whether partonic saturation delays or not in rapidity when going beyond the leading order. In our investigation, we use the so called 'rapidity veto' which forbid two emissions to be very close in rapidity, to 'switch on' higher order corrections to the BK equation. From analytic and numerical analysis, we conclude that indeed saturation does delay in rapidity when higher order corrections are taken into account. In the last part, we investigate higher order QCD corrections as additional corrections to the Electroweak (EW) sector. The question of whether BFKL corrections are of any importance in the Regge limit for the EW sector seems natural; although they arise in higher loop level, the accumulation of logarithms in energy s at high energies, cannot be dismissed without an investigation. We focus on the process γγ→ZZ. We calculate the pQCD corrections in the forward region at leading logarithmic (LL) BFKL accuracy, which are of the order of few percent at the TeV energy scale. (orig.)

Higher order QCD corrections in small x physics

Energy Technology Data Exchange (ETDEWEB)

Chachamis, G.

2006-11-15

We study higher order QCD corrections in small x Physics. The numerical implementation of the full NLO photon impact factor is the remaining necessary piece for the testing of the NLO BFKL resummation against data from physical processes, such as {gamma}{sup *}{gamma}{sup *} collisions. We perform the numerical integration over phase space for the virtual corrections to the NLO photon impact factor. This, along with the previously calculated real corrections, makes feasible in the near future first estimates for the {gamma}*{gamma}* total cross section, since the convolution of the full impact factor with the NLO BFKL gluon Green's function is now straightforward. The NLO corrections for the photon impact factor are sizeable and negative. In the second part of this thesis, we estimate higher order correction to the BK equation. We are mainly interested in whether partonic saturation delays or not in rapidity when going beyond the leading order. In our investigation, we use the so called 'rapidity veto' which forbid two emissions to be very close in rapidity, to 'switch on' higher order corrections to the BK equation. From analytic and numerical analysis, we conclude that indeed saturation does delay in rapidity when higher order corrections are taken into account. In the last part, we investigate higher order QCD corrections as additional corrections to the Electroweak (EW) sector. The question of whether BFKL corrections are of any importance in the Regge limit for the EW sector seems natural; although they arise in higher loop level, the accumulation of logarithms in energy s at high energies, cannot be dismissed without an investigation. We focus on the process {gamma}{gamma}{yields}ZZ. We calculate the pQCD corrections in the forward region at leading logarithmic (LL) BFKL accuracy, which are of the order of few percent at the TeV energy scale. (orig.)

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

Science.gov (United States)

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

2012-08-01

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. In this paper, the MCI is similar to the conformity index suggested by Paddick (CI(Paddick)), 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 0.1-1.1 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 CI(Paddick). The measurements of MCI in head-neck cancers treated with intensity-modulated radiation therapy and volumetric-modulated arc therapy provide a window on its clinical practice. 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 CI(Paddick) are also provided. 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 dose-volume histogram, it will be a more useful conformity index.

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

Energy Technology Data Exchange (ETDEWEB)

Hess-Flores, Mauricio [Univ. of California, Davis, CA (United States)

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

Establishment of regression dependences. Linear and nonlinear dependences

International Nuclear Information System (INIS)

Onishchenko, A.M.

1994-01-01

The main problems of determination of linear and 19 types of nonlinear regression dependences are completely discussed. It is taken into consideration that total dispersions are the sum of measurement dispersions and parameter variation dispersions themselves. Approaches to all dispersions determination are described. It is shown that the least square fit gives inconsistent estimation for industrial objects and processes. The correction methods by taking into account comparable measurement errors for both variable give an opportunity to obtain consistent estimation for the regression equation parameters. The condition of the correction technique application expediency is given. The technique for determination of nonlinear regression dependences taking into account the dependence form and comparable errors of both variables is described. 6 refs., 1 tab

A method to identify dependencies between organizational factors using statistical independence test

International Nuclear Information System (INIS)

Kim, Y.; Chung, C.H.; Kim, C.; Jae, M.; Jung, J.H.

2004-01-01

A considerable number of studies on organizational factors in nuclear power plants have been made especially in recent years, most of which have assumed organizational factors to be independent. However, since organizational factors characterize the organization in terms of safety and efficiency etc. and there would be some factors that have close relations between them. Therefore, from whatever point of view, if we want to identify the characteristics of an organization, the dependence relationships should be considered to get an accurate result. In this study the organization of a reference nuclear power plant in Korea was analyzed for the trip cases of that plant using 20 organizational factors that Jacobs and Haber had suggested: 1) coordination of work, 2) formalization, 3) organizational knowledge, 4) roles and responsibilities, 5) external communication, 6) inter-department communications, 7) intra-departmental communications, 8) organizational culture, 9) ownership, 10) safety culture, 11) time urgency, 12) centralization, 13) goal prioritization, 14) organizational learning, 15) problem identification, 16) resource allocation, 17) performance evaluation, 18) personnel selection, 19) technical knowledge, and 20) training. By utilizing the results of the analysis, a method to identify the dependence relationships between organizational factors is presented. The statistical independence test for the analysis result of the trip cases is adopted to reveal dependencies. This method is geared to the needs to utilize many kinds of data that has been obtained as the operating years of nuclear power plants increase, and more reliable dependence relations may be obtained by using these abundant data

Bias correction for rainrate retrievals from satellite passive microwave sensors

Science.gov (United States)

Short, David A.

1990-01-01

Rainrates retrieved from past and present satellite-borne microwave sensors are affected by a fundamental remote sensing problem. Sensor fields-of-view are typically large enough to encompass substantial rainrate variability, whereas the retrieval algorithms, based on radiative transfer calculations, show a non-linear relationship between rainrate and microwave brightness temperature. Retrieved rainrates are systematically too low. A statistical model of the bias problem shows that bias correction factors depend on the probability distribution of instantaneous rainrate and on the average thickness of the rain layer.

Application of geometry correction factors for low-level waste package dose measurements. Revision 1

International Nuclear Information System (INIS)

Chandler, M.C.; Parish, B.

1995-01-01

Plans are to determine the Cs-137 content of low-level waste packages generated in High-Level Waste by measuring the radiation level at a specified distance from the package with a hand-held radiation instrument. The measurement taken at this specified distance, either 3 or 5 feet, is called the far-field measurement. This report documents a method for adjusting the gamma exposure rate (mR/hr) reading used in dose-to-curie determinations when the far-field measurement equals the background reading. This adjustment is necessary to reduce the conservatism resulting from using a minimum detection limit exposure rate for the dose-to-curie determination for the far-field measurement position. To accomplish this adjustment, the near-field (5 cm) measurement is multiplied by a geometry correction factor to obtain an estimate of the far field exposure rate (which is below instrument sensitivity). This estimate of the far field exposure rate is used to estimate the Cs-137 curie content of the package. This report establishes the geometry correction factors for the dose-to-curie determination when the far-field gamma exposure measurement equals the background reading. This report also provides a means of demonstrating compliance to 1S Manual requirements for exposure rate readings at different locations from waste packages while specifying only two measurement positions. This demonstration of compliance is necessary to minimize the number of locations exposure rate measurements that are required, i.e., ALARA

Estimation of the self-attenuation correction factor for gamma rays emission from nuclear materials

International Nuclear Information System (INIS)

Badawy, A.; El-Gammal, W.A.

2001-01-01

This work presents an investigation of the self-attenuation of gamma-rays emission from nuclear materials (NMs) for measuring the U-235 enrichment, U-235 mass content and isotopic composition of NMs by non-destructive assay technique [NDA]. The measurements then would not need the use of suitable NM Standards which may not be available in many situations. The self-attenuation correction factor (F) may be estimated by the use of the linear attenuation factor of the assayed sample, the geometrical configuration of the assay set-up and the position of the assayed sample relative to the detector. A developed mathematical analysis makes use of specific parameters which affect the estimation of the self-attenuation of the source-detector system which emits passive gamma-rays at certain prominent signatures

Stress Management in Correctional Recreation.

Science.gov (United States)

Card, Jaclyn A.

Current economic conditions have created additional sources of stress in the correctional setting. Often, recreation professionals employed in these settings also add to inmate stress. One of the major factors limiting stress management in correctional settings is a lack of understanding of the value, importance, and perceived freedom, of leisure.…

Temperature dependent structural and vibrational properties of liquid indium

Science.gov (United States)

Patel, A. B.; Bhatt, N. K.

2018-05-01

The influence of the temperature effect on both the structure factor and the phonon dispersion relation of liquid indium have been investigated by means of pseudopotential theory. The Percus-Yevick Hard Sphere reference system is applied to describe the structural calculation. The effective electron-ion interaction is explained by using modified empty core potential due to Hasegawa et al. along with a local field correction function due to Ichimaru-Utsumi (IU). The temperature dependence of pair potential needed at higher temperatures was achieved by multiplying the damping factor exp(- π/kBT2k F r ) in the pair potential. Very close agreement of static structure factor, particularly, at elevated temperatures confirms the validity of the local potential. A positive dispersion is found in low-q region and the correct trend of phonon dispersion branches like the experimental; shows all broad features of collective excitations in liquid metals.

State-dependent factors and attention in Whiplash Associated Disorder

NARCIS (Netherlands)

Blokhorst, Mariëtte G.B.G.

2005-01-01

The main aim of this thesis is to investigate the relationship between state- dependent factors (headache, neck pain, fatigue, distress) and attention in WAD patients. Furthermore, the focus is on ‘noise-distractibility’ and ‘noise- intolerance’, which are symptoms related to attention and often

Research on Power Factor Correction Boost Inductor Design Optimization – Efficiency vs. Power Density

DEFF Research Database (Denmark)

Li, Qingnan; Andersen, Michael A. E.; Thomsen, Ole Cornelius

2011-01-01

Nowadays, efficiency and power density are the most important issues for Power Factor Correction (PFC) converters development. However, it is a challenge to reach both high efficiency and power density in a system at the same time. In this paper, taking a Bridgeless PFC (BPFC) as an example......, a useful compromise between efficiency and power density of the Boost inductors on 3.2kW is achieved using an optimized design procedure. The experimental verifications based on the optimized inductor are carried out from 300W to 3.2kW at 220Vac input....

Determination of self absorption correction factor (SAF) for gross alpha measurement in water samples by BIS method

International Nuclear Information System (INIS)

Raveendran, Nanda; Baburajan, A.; Ravi, P.M.

2018-01-01

The laboratories accredited by AERB undertake the measurement of gross alpha and gross beta in packaged drinking water from manufactures across the country and analyze as per the procedure of Bureau of Indian standards. The accurate measurements of gross alpha in the drinking water sample is a challenge due to the self absorption of alpha particle from varying precipitate (Fe(OH) 3 +BaSO 4 ) thickness and total dissolved solids (TDS). This paper deals with a study on tracer recovery generation and self absorption correction factor (SAF). ESL, Tarapur has participated in an inter-laboratory comparison exercise conducted by IDS, RSSD, BARC as per the recommendation of AERB for the accredited laboratories. The thickness of the precipitate is an important aspect which affected the counting process. The activity was reported after conducting multiple experiments with uranium tracer recovery and precipitate thickness. Later on to make our efforts simplified, an average tracer recovery and Self Absorption correction Factor (SAF) was derived by the present experiment and the same was used for the re-calculation of activity from the count rate reported earlier

Specificity of genetic and environmental risk factors for symptoms of cannabis, cocaine, alcohol, caffeine, and nicotine dependence.

Science.gov (United States)

Kendler, Kenneth S; Myers, John; Prescott, Carol A

2007-11-01

Although genetic risk factors have been found to contribute to dependence on both licit and illicit psychoactive substances, we know little of how these risk factors interrelate. To clarify the structure of genetic and environmental risk factors for symptoms of dependence on cannabis, cocaine, alcohol, caffeine, and nicotine in males and females. Lifetime history by structured clinical interview. General community. Four thousand eight hundred sixty-five members of male-male and female-female pairs from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders. Main Outcome Measure Lifetime symptoms of abuse of and dependence on cannabis, cocaine, alcohol, caffeine, and nicotine. Controlling for greater symptom prevalence in males, genetic and environmental parameters could be equated across sexes. Two models explained the data well. The best-fit exploratory model contained 2 genetic factors and 1 individual environmental factor contributing to all substances. The first genetic factor loaded strongly on cocaine and cannabis dependence; the second, on alcohol and nicotine dependence. Nicotine and caffeine had high substance-specific genetic effects. A confirmatory model, which also fit well, contained 1 illicit drug genetic factor--loading only on cannabis and cocaine--and 1 licit drug genetic factor loading on alcohol, caffeine, and nicotine. However, these factors were highly intercorrelated (r = + 0.82). Large substance-specific genetic effects remained for nicotine and caffeine. The pattern of genetic and environmental risk factors for psychoactive substance dependence was similar in males and females. Genetic risk factors for dependence on common psychoactive substances cannot be explained by a single factor. Rather, 2 genetic factors-one predisposing largely to illicit drug dependence, the other primarily to licit drug dependence-are needed. Furthermore, a large proportion of the genetic influences on nicotine and particularly caffeine dependence

Recombination clumping factor during cosmic reionization

International Nuclear Information System (INIS)

Kaurov, Alexander A.; Gnedin, Nickolay Y.

2014-01-01

We discuss the role of recombinations in the intergalactic medium, and the related concept of the clumping factor, during cosmic reionization. The clumping factor is, in general, a local quantity that depends on both the local overdensity and the scale below which the baryon density field can be assumed smooth. That scale, called the filtering scale, depends on over-density and local thermal history. We present a method for building a self-consistent analytical model of inhomogeneous reionization, assuming the linear growth rate of the density fluctuation, which simultaneously accounts for these effects. We show that taking into account the local clumping factor introduces significant corrections to the total recombination rate, compared to the model with a globally uniform clumping factor.

Correction of the closed orbit and vertical dispersion and the tuning and field correction system in ISABELLE

International Nuclear Information System (INIS)

Parzen, G.

1979-01-01

Each ring in ISABELLE will have 10 separately powered systematic field correction coils to make required corrections which are the same in corresponding magnets around the ring. These corrections include changing the ν-value, shaping the working line in ν-space, correction of field errors due to iron saturation effects, the conductor arrangements, the construction of the coil ends, diamagnetic effects in the superconductor and to rate-dependent induced currents. The twelve insertion quadrupoles in the insertion surrounding each crossing point will each have a quadrupole trim coil. The closed orbit will be controlled by a system of 84 horizontal dipole coils and 90 vertical dipole coils in each ring, each coil being separately powered. This system of dipole coils will also be used to correct the vertical dispersion at the crossing points. Two families of skew quadrupoles per ring will be provided for correction of the coupling between the horizontal and vertical motions. Although there will be 258 separately powered correction coils in each ring

Combination of recombinant factor VIIa and fibrinogen corrects clot formation in primary immune thrombocytopenia at very low platelet counts

DEFF Research Database (Denmark)

Larsen, Ole H; Stentoft, Jesper; Radia, Deepti

2013-01-01

Haemostatic treatment modalities alternative to platelet transfusion are desirable to control serious acute bleeds in primary immune thrombocytopenia (ITP). This study challenged the hypothesis that recombinant activated factor VII (rFVIIa) combined with fibrinogen concentrate may correct whole b...

Comparison between two methodologies for uniformity correction of extensive reference sources

International Nuclear Information System (INIS)

Junior, Iremar Alves S.; Siqueira, Paulo de T.D.; Vivolo, Vitor; Potiens, Maria da Penha A.; Nascimento, Eduardo

2016-01-01

This article presents the procedures to obtain the uniformity correction factors for extensive reference sources proposed by two different methodologies. The first methodology is presented by the Good Practice Guide of Nº 14 of the NPL, which provides a numerical correction. The second one uses the radiation transport code, MCNP5, to obtain the correction factor. Both methods retrieve very similar corrections factor values, with a maximum deviation of 0.24%. (author)

The applicability of correction factor for corneal thickness on non-contact tonometer measured intraocular pressure in LASIK treated eyes.

Science.gov (United States)

Jethani, Jitendra; Dave, Paaraj; Jethani, Monica; Desai, Yogesh; Patel, Purvi

2016-01-01

To determine the applicability of central corneal thickness (CCT) based correction factor for non-contact tonometer (NCT) measured intraocular pressure (IOP) readings. A prospective, non-randomized study involved 346 eyes of 173 consecutive patients with age ⩾21 years undergoing laser-assisted in situ keratomileusis (LASIK) for myopia and/or myopic astigmatism. The CCT and IOP were measured before and after the LASIK procedure. The IOP pre and post-LASIK was compared after applying the correction factor for CCT. Patients not completing the 3 month postoperative follow-up were excluded. The median spherical equivalent before undergoing LASIK was -4.25D (inter-quartile range, -3.25D). The mean preoperative CCT was 536.82 ± 33.71 μm which reduced to 477.55 ± 39.3 μm (p < 0.01) post-LASIK. The mean IOP reduced from a preoperative value of 14.6 ± 2.32 mmHg to 10.64 ± 2.45 mmHg postoperatively (p < 0.01). On applying correction for the corneal thickness, the pre and postoperative IOP was 15.14 ± 2.8 mmHg and 15.37 ± 2.65 mmHg (p = 0.06) respectively with a strong positive correlation (r = 0.7, p < 0.01). Three hundred eyes (86.7%) had an absolute difference in IOP of less than 3.0 mmHg post-CCT correction which is within the retest variability of NCT. Only 46 eyes (13.3%) had an absolute difference of more than 3.0 mmHg. The modified Ehler's correction algorithm used in this study can be effectively applied in the normal IOP range in a majority of patients.

Volume fraction dependence of transient absorption signal and nonlinearities in metal nanocolloids

International Nuclear Information System (INIS)

Jayabalan, J; Singh, Asha; Khan, Salahuddin; Chari, Rama

2013-01-01

Electron–lattice thermalization dynamics in metal nanoparticles or in bulk metal is usually estimated by measuring the decay time of the change in transmission following an optical excitation. Such measurements can be performed in transient absorption geometry using a femtosecond laser. We find that for silver nanoplatelet/water colloids, the decay time of the transient absorption depends on the volume fraction of silver in water. By estimating the volume fraction dependence of nonlinearities in the same samples, we show that the variation in the measured decay time is due to pump-depletion effects present in the sample. The correct correction factor for taking into account pump-depletion effects in fifth- and higher-order nonlinearities is also presented. (paper)

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.

Science.gov (United States)

Gu, Huidong; Liu, Guowen; Wang, Jian; Aubry, Anne-Françoise; 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 (σ) and the concentrations (x). The weighting factor of 1, 1/x, or 1/x(2) should be selected if, over the entire concentration range, σ is a constant, σ(2) is proportional to x, or σ 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.

Selection and optimization of spectrometric amplifiers for gamma spectrometry: part II - linearity, live time correction factors and software

International Nuclear Information System (INIS)

Moraes, Marco Antonio Proenca Vieira de; Pugliesi, Reinaldo

1996-01-01

The objective of the present work was to establish simple criteria to choose the best combination of electronic modules to achieve an adequate high resolution gamma spectrometer. Linearity, live time correction factors and softwares of a gamma spectrometric system composed by a Hp Ge detector have been studied by using several kinds of spectrometric amplifiers: Canberra 2021, Canberra 2025, Ortec 673 and Tennelec 244 and the MCA cards Ortec and Nucleus. The results showed low values of integral non-linearity for all spectrometric amplifiers connected to the Ortec and Nucleus boards. The MCA card should be able to correct amplifier dead time for 17 kcps count rates. (author)

Automated general temperature correction method for dielectric soil moisture sensors

Science.gov (United States)

Kapilaratne, R. G. C. Jeewantinie; Lu, Minjiao

2017-08-01

An effective temperature correction method for dielectric sensors is important to ensure the accuracy of soil water content (SWC) measurements of local to regional-scale soil moisture monitoring networks. These networks are extensively using highly temperature sensitive dielectric sensors due to their low cost, ease of use and less power consumption. Yet there is no general temperature correction method for dielectric sensors, instead sensor or site dependent correction algorithms are employed. Such methods become ineffective at soil moisture monitoring networks with different sensor setups and those that cover diverse climatic conditions and soil types. This study attempted to develop a general temperature correction method for dielectric sensors which can be commonly used regardless of the differences in sensor type, climatic conditions and soil type without rainfall data. In this work an automated general temperature correction method was developed by adopting previously developed temperature correction algorithms using time domain reflectometry (TDR) measurements to ThetaProbe ML2X, Stevens Hydra probe II and Decagon Devices EC-TM sensor measurements. The rainy day effects removal procedure from SWC data was automated by incorporating a statistical inference technique with temperature correction algorithms. The temperature correction method was evaluated using 34 stations from the International Soil Moisture Monitoring Network and another nine stations from a local soil moisture monitoring network in Mongolia. Soil moisture monitoring networks used in this study cover four major climates and six major soil types. Results indicated that the automated temperature correction algorithms developed in this study can eliminate temperature effects from dielectric sensor measurements successfully even without on-site rainfall data. Furthermore, it has been found that actual daily average of SWC has been changed due to temperature effects of dielectric sensors with a

Risk factors of dependency of Chilean older adults and consequences on informal caregiving

Directory of Open Access Journals (Sweden)

María Consuelo CHEIX DIEGUEZ

2015-12-01

Full Text Available  Based on the 2009 National Survey of Elderly Dependency we characterize older people who are dependent in Chile, and we compute multivariate logistic regression models to assess the factors associated with dependency. In addition to age and the presence of diseases, there are other factors that are associated with increased prevalence of dependence, such as educational level, quality of family relationships and conducting activities such as physical exercise and reading. We also characterize and describe the level of well-being of the informal caregivers of the dependent persons. Stress informal caregiver is expressed both by an increase in depressive feelings and overload, as well as by a deterioration of physical health, who also tend to be women, older, low educational levels, intensifying further vulnerability context of this group.

Proton dose distribution measurements using a MOSFET detector with a simple dose-weighted correction method for LET effects.

Science.gov (United States)

Kohno, Ryosuke; Hotta, Kenji; Matsuura, Taeko; Matsubara, Kana; Nishioka, Shie; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

2011-04-04

We experimentally evaluated the proton beam dose reproducibility, sensitivity, angular dependence and depth-dose relationships for a new Metal Oxide Semiconductor Field Effect Transistor (MOSFET) detector. The detector was fabricated with a thinner oxide layer and was operated at high-bias voltages. In order to accurately measure dose distributions, we developed a practical method for correcting the MOSFET response to proton beams. The detector was tested by examining lateral dose profiles formed by protons passing through an L-shaped bolus. The dose reproducibility, angular dependence and depth-dose response were evaluated using a 190 MeV proton beam. Depth-output curves produced using the MOSFET detectors were compared with results obtained using an ionization chamber (IC). Since accurate measurements of proton dose distribution require correction for LET effects, we developed a simple dose-weighted correction method. The correction factors were determined as a function of proton penetration depth, or residual range. The residual proton range at each measurement point was calculated using the pencil beam algorithm. Lateral measurements in a phantom were obtained for pristine and SOBP beams. The reproducibility of the MOSFET detector was within 2%, and the angular dependence was less than 9%. The detector exhibited a good response at the Bragg peak (0.74 relative to the IC detector). For dose distributions resulting from protons passing through an L-shaped bolus, the corrected MOSFET dose agreed well with the IC results. Absolute proton dosimetry can be performed using MOSFET detectors to a precision of about 3% (1 sigma). A thinner oxide layer thickness improved the LET in proton dosimetry. By employing correction methods for LET dependence, it is possible to measure absolute proton dose using MOSFET detectors.

Proton dose distribution measurements using a MOSFET detector with a simple dose‐weighted correction method for LET effects

Science.gov (United States)

Hotta, Kenji; Matsuura, Taeko; Matsubara, Kana; Nishioka, Shie; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

2011-01-01

We experimentally evaluated the proton beam dose reproducibility, sensitivity, angular dependence and depth‐dose relationships for a new Metal Oxide Semiconductor Field Effect Transistor (MOSFET) detector. The detector was fabricated with a thinner oxide layer and was operated at high‐bias voltages. In order to accurately measure dose distributions, we developed a practical method for correcting the MOSFET response to proton beams. The detector was tested by examining lateral dose profiles formed by protons passing through an L‐shaped bolus. The dose reproducibility, angular dependence and depth‐dose response were evaluated using a 190 MeV proton beam. Depth‐output curves produced using the MOSFET detectors were compared with results obtained using an ionization chamber (IC). Since accurate measurements of proton dose distribution require correction for LET effects, we developed a simple dose‐weighted correction method. The correction factors were determined as a function of proton penetration depth, or residual range. The residual proton range at each measurement point was calculated using the pencil beam algorithm. Lateral measurements in a phantom were obtained for pristine and SOBP beams. The reproducibility of the MOSFET detector was within 2%, and the angular dependence was less than 9%. The detector exhibited a good response at the Bragg peak (0.74 relative to the IC detector). For dose distributions resulting from protons passing through an L‐shaped bolus, the corrected MOSFET dose agreed well with the IC results. Absolute proton dosimetry can be performed using MOSFET detectors to a precision of about 3% (1 sigma). A thinner oxide layer thickness improved the LET in proton dosimetry. By employing correction methods for LET dependence, it is possible to measure absolute proton dose using MOSFET detectors. PACS number: 87.56.‐v

ATP-Dependent Chromatin Remodeling Factors and Their Roles in Affecting Nucleosome Fiber Composition

Directory of Open Access Journals (Sweden)

Alexandra Lusser

2011-10-01

Full Text Available ATP-dependent chromatin remodeling factors of the SNF2 family are key components of the cellular machineries that shape and regulate chromatin structure and function. Members of this group of proteins have broad and heterogeneous functions ranging from controlling gene activity, facilitating DNA damage repair, promoting homologous recombination to maintaining genomic stability. Several chromatin remodeling factors are critical components of nucleosome assembly processes, and recent reports have identified specific functions of distinct chromatin remodeling factors in the assembly of variant histones into chromatin. In this review we will discuss the specific roles of ATP-dependent chromatin remodeling factors in determining nucleosome composition and, thus, chromatin fiber properties.

Correction Technique for Raman Water Vapor Lidar Signal-Dependent Bias and Suitability for Water Wapor Trend Monitoring in the Upper Troposphere

Science.gov (United States)

Whiteman, D. N.; Cadirola, M.; Venable, D.; Calhoun, M.; Miloshevich, L; Vermeesch, K.; Twigg, L.; Dirisu, A.; Hurst, D.; Hall, E.;

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

International Nuclear Information System (INIS)

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

2014-01-01

ZnO thin films degenerately doped with Si (Si x Zn 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 x Zn 1−x O films in the entire temperature range. On the contrary, the Si x Zn 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

Volume dependence of N-body bound states

Science.gov (United States)

König, Sebastian; Lee, Dean

2018-04-01

We derive the finite-volume correction to the binding energy of an N-particle quantum bound state in a cubic periodic volume. Our results are applicable to bound states with arbitrary composition and total angular momentum, and in any number of spatial dimensions. The only assumptions are that the interactions have finite range. The finite-volume correction is a sum of contributions from all possible breakup channels. In the case where the separation is into two bound clusters, our result gives the leading volume dependence up to exponentially small corrections. If the separation is into three or more clusters, there is a power-law factor that is beyond the scope of this work, however our result again determines the leading exponential dependence. We also present two independent methods that use finite-volume data to determine asymptotic normalization coefficients. The coefficients are useful to determine low-energy capture reactions into weakly bound states relevant for nuclear astrophysics. Using the techniques introduced here, one can even extract the infinite-volume energy limit using data from a single-volume calculation. The derived relations are tested using several exactly solvable systems and numerical examples. We anticipate immediate applications to lattice calculations of hadronic, nuclear, and cold atomic systems.

Risk and Protective Factors for Nicotine Dependence in Adolescence

Science.gov (United States)

Hu, Mei-Chen; Griesler, Pamela; Schaffran, Christine; Kandel, Denise

2011-01-01

Background: We investigated the role of psychosocial and proximal contextual factors on nicotine dependence in adolescence. Methods: Data on a multiethnic cohort of 6th to 10th graders from the Chicago public schools were obtained from four household interviews conducted with adolescents over two years and one interview with mothers. Structural…

Attenuation correction method for single photon emission CT

Energy Technology Data Exchange (ETDEWEB)

Morozumi, Tatsuru; Nakajima, Masato [Keio Univ., Yokohama (Japan). Faculty of Science and Technology; Ogawa, Koichi; Yuta, Shinichi

1983-10-01

A correction method (Modified Correction Matrix method) is proposed to implement iterative correction by exactly measuring attenuation constant distribution in a test body, calculating a correction factor for every picture element, then multiply the image by these factors. Computer simulation for the comparison of the results showed that the proposed method was specifically more effective to an application to the test body, in which the rate of attenuation constant change is large, than the conventional correction matrix method. Since the actual measurement data always contain quantum noise, the noise was taken into account in the simulation. However, the correction effect was large even under the noise. For verifying its clinical effectiveness, the experiment using an acrylic phantom was also carried out. As the result, the recovery of image quality in the parts with small attenuation constant was remarkable as compared with the conventional method.

Commonalities in the psychological factors associated with problem gambling and Internet dependence.

Science.gov (United States)

Dowling, N A; Brown, M

2010-08-01

The most commonly applied conceptual approach for excessive Internet use has been as a behavioral addiction, similar to pathological or problem gambling. In order to contribute to the understanding of Internet dependence as a disorder resembling problem gambling, the current study aimed to examine the relationship between problem gambling and Internet dependence and the degree to which psychological factors associated with problem gambling are relevant to the study of Internet dependence. The factors of depression, anxiety, student stressors, loneliness, and social support were examined in a sample of university students from several Australian universities. The findings revealed that there is no overlap between the populations reporting problem gambling and Internet dependence, but that individuals with these disorders report similar psychological profiles. Although requiring replication with larger community samples and longitudinal designs, these preliminary findings suggest that problem gambling and Internet dependence may be separate disorders with common underlying etiologies or consequences. The implications of the findings in relation to the conceptualization and management of these disorders are briefly discussed.

Determination of geometry correction factors to different vials used to radiopharmaceutical activity measurements

International Nuclear Information System (INIS)

Kuahara, Lilian T.; Correa, Eduardo L.; Potiens, Maria da Penha A.

2015-01-01

The aim of this study is to present the geometry correction factors and their respective uncertainties to P6 and 10R vials and 3 mL and 5 mL plastic syringes using the reference activity meters present at the Laboratorio de Calibracao de Instrumentos (LCI), IPEN the secondary standard system Capintec NPL-CRC radionuclide calibrator, with traceability to the National Physics Laboratory (NPL), England and the work standard Capintec CRC-15BT and the Capintec CRC-25R. The procedure was made using 99m Tc, which is responsible for about 80 % of the routine procedures in a nuclear medicine service. Variations of up to 40 % between different vials using the same radionuclide were found. (author)

Factors Predicting Ventilator Dependence in Patients with Ventilator-Associated Pneumonia

Directory of Open Access Journals (Sweden)

Chia-Cheng Tseng

2012-01-01

Full Text Available Objectives. To determine risk factors associated with ventilator dependence in patients with ventilator-associated pneumonia (VAP. Study Design. A retrospective study was conducted at Chang Gung Memorial Hospital, Kaohsiung, from January 1, 2007 to January 31, 2008. Methods. This study evaluated 163 adult patients (aged ≥18 years. Eligibility was evaluated according to the criterion for VAP, Sequential Organ Failure Assessment (SOFA score, Acute Physiological Assessment and Chronic Health Evaluation II (APACHE II score. Oxygenation index, underlying comorbidities, septic shock status, previous tracheostomy status, and factors related to pneumonia were collected for analysis. Results. Of the 163 VAP patients in the study, 90 patients survived, yielding a mortality rate of 44.8%. Among the 90 surviving patients, only 36 (40% had been weaned off ventilators at the time of discharge. Multivariate logistic regression analysis was used to identify underlying factors such as congestive cardiac failure (P=0.009, initial high oxygenation index value (P=0.04, increased SOFA scores (P=0.01, and increased APACHE II scores (P=0.02 as independent predictors of ventilator dependence. Results from the Kaplan-Meier method indicate that initial therapy with antibiotics could increase the ventilator weaning rate (log Rank test, P<0.001. Conclusions. Preexisting cardiopulmonary function, high APACHE II and SOFA scores, and high oxygenation index were the strongest predictors of ventilator dependence. Initial empiric antibiotic treatment can improve ventilator weaning rates at the time of discharge.

Thermal neutron self-shielding correction factors for large sample instrumental neutron activation analysis using the MCNP code

International Nuclear Information System (INIS)

Tzika, F.; Stamatelatos, I.E.

2004-01-01

Thermal neutron self-shielding within large samples was studied using the Monte Carlo neutron transport code MCNP. The code enabled a three-dimensional modeling of the actual source and geometry configuration including reactor core, graphite pile and sample. Neutron flux self-shielding correction factors derived for a set of materials of interest for large sample neutron activation analysis are presented and evaluated. Simulations were experimentally verified by measurements performed using activation foils. The results of this study can be applied in order to determine neutron self-shielding factors of unknown samples from the thermal neutron fluxes measured at the surface of the sample

Paediatric lower limb deformity correction using the Ilizarov technique: a statistical analysis of factors affecting the complication rate.

Science.gov (United States)

Oostenbroek, Hubert J; Brand, Ronald; van Roermund, Peter M; Castelein, René M

2014-01-01

Limb length discrepancy (LLD) and other patient factors are thought to influence the complication rate in (paediatric) limb deformity correction. In the literature, information is conflicting. This study was performed to identify clinical factors that affect the complication rate in paediatric lower-limb lengthening. A consecutive group of 37 children was analysed. The median proportionate LLD was 15 (4-42)%. An analysis was carried out on several patient factors that may complicate the treatment or end result using logistic regression in a polytomous logistic regression model. The factors analysed were proportionate LLD, cause of deformity, location of corrected bone, and the classification of the deformity according to an overall classification that includes the LLD and all concomitant deformity factors. The median age at the start of the treatment was 11 (6-17) years. The median lengthening index was 1.5 (0.8-3.8) months per centimetre lengthening. The obstacle and complication rate was 69% per lengthened bone. Proportionate LLD was the only statistically significant predictor for the occurrence of complications. Concomitant deformities did not influence the complication rate. From these data we constructed a simple graph that shows the relationship between proportionate LLD and risk for complications. This study shows that only relative LLD is a predictor of the risk for complications. The additional value of this analysis is the production of a simple graph. Construction of this graph using data of a patient group (for example, your own) may allow a more realistic comparison with results in the literature than has been possible before.

Regularization scheme dependence of virtual corrections to DY and DIS

International Nuclear Information System (INIS)

Khalafi, F.; Landshoff, P.V.

1981-01-01

One loop virtual corrections to the quark photon vertex are calculated under various assumptions and their sensitivity to the manner in which infra-red and mass singularities are regularized is studied. A method based on the use of Mellin-transforms in the Feynman parametric space is developed and shown to be convenient in calculating virtual diagrams beyond the leading logarithm in perturbative QCD. (orig.)

Some recoil corrections to the hydrogen hyperfine splitting

International Nuclear Information System (INIS)

Bodwin, G.T.; Yennie, D.R.

1988-01-01

We compute all of the recoil corrections to the ground-state hyperfine splitting in hydrogen, with the exception of the proton polarizability, that are required to achieve an accuracy of 1 ppm. Our approach includes a unified treatment of the corrections that would arise from a pointlike Dirac proton and the corrections that are due to the proton's non-QED structure. Our principal new results are a calculation of the relative order-α 2 (m/sub e//m/sub p/) contributions that arise from the proton's anomalous magnetic moment and a systematic treatment of the relative order-α(m/sub e//m/sub p/) contributions that arise from form-factor corrections. In the former calculation we introduce some new technical improvements and are able to evaluate all of the expressions analytically. In the latter calculation, which has been the subject of previous investigations by other authors, we express the form-factor corrections in terms of two-dimensional integrals that are convenient for numerical evaluation and present numerical results for the commonly used dipole parametrization of the form factors. Because we use a parametrization of the form factors that differs slightly from the ones used in previous work, our numerical results are shifted from older ones by a small amount

Ambiguities in the grid-inefficiency correction for Frisch-Grid Ionization Chambers

International Nuclear Information System (INIS)

Al-Adili, A.; Hambsch, F.-J.; Bencardino, R.; Oberstedt, S.; Pomp, S.

2012-01-01

Ionization chambers with Frisch grids have been very successfully applied to neutron-induced fission-fragment studies during the past 20 years. They are radiation resistant and can be easily adapted to the experimental conditions. The use of Frisch grids has the advantage to remove the angular dependency from the charge induced on the anode plate. However, due to the Grid Inefficiency (GI) in shielding the charges, the anode signal remains slightly angular dependent. The correction for the GI is, however, essential to determine the correct energy of the ionizing particles. GI corrections can amount to a few percent of the anode signal. Presently, two contradicting correction methods are considered in literature. The first method adding the angular-dependent part of the signal to the signal pulse height; the second method subtracting the former from the latter. Both additive and subtractive approaches were investigated in an experiment where a Twin Frisch-Grid Ionization Chamber (TFGIC) was employed to detect the spontaneous fission fragments (FF) emitted by a 252 Cf source. Two parallel-wire grids with different wire spacing (1 and 2 mm, respectively), were used individually, in the same chamber side. All the other experimental conditions were unchanged. The 2 mm grid featured more than double the GI of the 1 mm grid. The induced charge on the anode in both measurements was compared, before and after GI correction. Before GI correction, the 2 mm grid resulted in a lower pulse-height distribution than the 1 mm grid. After applying both GI corrections to both measurements only the additive approach led to consistent grid independent pulse-height distributions. The application of the subtractive correction on the contrary led to inconsistent, grid-dependent results. It is also shown that the impact of either of the correction methods is small on the FF mass distributions of 235 U(n th , f).

Evaluation of design safety factors for time-dependent buckling

International Nuclear Information System (INIS)

Stone, C.M.; Nickell, R.E.

1977-02-01

The ASME Boiler and Pressure Vessel Code rules concerning time-dependent (creep) buckling for Class 1 nuclear components have recently been changed. Previous requirements for a factor of ten on service life have been replaced with a factor of safety of 1.5 on loading for load-controlled buckling. This report examines the supposed equivalence of the two rules from the standpoint of materials behavior--specifically, the secondary creep strain rate exponent. The comparison is made using results obtained numerically for an axially-loaded, cylindrical shell with varying secondary creep exponents. A computationally efficient scheme for analyzing creep buckling problems is also presented

A temperature-dependent gain control system for improving the stability of Si-PM-based PET systems

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Satomi, Junkichi; Watabe, Tadashi; Imaizumi, Masao; Shimosegawa, Eku; Hatazawa, Jun; Watabe, Hiroshi; Kanai, Yasukazu

2011-01-01

The silicon-photomultiplier (Si-PM) is a promising photodetector for the development of new PET systems due to its small size, high gain and relatively low sensitivity to the static magnetic field. One drawback of the Si-PM is that it has significant temperature-dependent gain that poses a problem for the stability of the Si-PM-based PET system. To reduce this problem, we developed and tested a temperature-dependent gain control system for the Si-PM-based PET system. The system consists of a thermometer, analog-to-digital converter, personal computer, digital-to-analog converter and variable gain amplifiers in the weight summing board of the PET system. Temperature characteristics of the Si-PM array are measured and the calculated correction factor is sent to the variable gain amplifier. Without this correction, the temperature-dependent peak channel shifts of the block detector were -55% from 20 deg. C to 35 deg.C. With the correction, the peak channel variations were corrected within ±8%. The coincidence count rate of the Si-PM-based PET system was measured using a Na-22 point source while monitoring the room temperature. Without the correction, the count rate inversely changed with the room temperature by 10% for 1.5 deg. C temperature changes. With the correction, the count rate variation was reduced to within 3.7%. These results indicate that the developed temperature-dependent gain control system can contribute to improving the stability of Si-PM-based PET systems.

Reliability Analysis of a Composite Wind Turbine Blade Section Using the Model Correction Factor Method: Numerical Study and Validation

DEFF Research Database (Denmark)

Dimitrov, Nikolay Krasimirov; Friis-Hansen, Peter; Berggreen, Christian

2013-01-01

by the composite failure criteria. Each failure mode has been considered in a separate component reliability analysis, followed by a system analysis which gives the total probability of failure of the structure. The Model Correction Factor method used in connection with FORM (First-Order Reliability Method) proved...

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

DEFF Research Database (Denmark)

Palmans, Hugo; Al-Sulaiti, L; Andreo, P

2013-01-01

, 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...

Monte Carlo calculation of correction factors for radionuclide neutron source emission rate measurement by manganese bath method

International Nuclear Information System (INIS)

Li Chunjuan; Liu Yi'na; Zhang Weihua; Wang Zhiqiang

2014-01-01

The manganese bath method for measuring the neutron emission rate of radionuclide sources requires corrections to be made for emitted neutrons which are not captured by manganese nuclei. The Monte Carlo particle transport code MCNP was used to simulate the manganese bath system of the standards for the measurement of neutron source intensity. The correction factors were calculated and the reliability of the model was demonstrated through the key comparison for the radionuclide neutron source emission rate measurements organized by BIPM. The uncertainties in the calculated values were evaluated by considering the sensitivities to the solution density, the density of the radioactive material, the positioning of the source, the radius of the bath, and the interaction cross-sections. A new method for the evaluation of the uncertainties in Monte Carlo calculation was given. (authors)

TH-CD-BRA-05: First Water Calorimetric Dw Measurement and Direct Measurement of Magnetic Field Correction Factors, KQ,B, in a 1.5 T B-Field of An MRI Linac

Energy Technology Data Exchange (ETDEWEB)

Prez, L de; Pooter, J de; Jansen, B [VSL, Delft (Netherlands); Wolthaus, J; Asselen, B van; Woodings, S; Soest, T; Kok, J; Raaymakers, B [University Medical Center Utrecht, Utrecht (Netherlands)

2016-06-15

Purpose: Reference dosimetry in MR-guided radiotherapy is performed in the presence of a B-field. As a consequence the response of ionization chambers changes considerably and depends on parameters not considered in traditional reference dosimetry. Therefore future Codes of Practices need ionization chamber correction factors to correct for both the change in beam quality and the presence of a B-field. The objective was to study the feasibility of water calorimetric absorbed-dose measurements in a 1.5 T B-field of an MRLinac and the direct measurement of kQ,B calibration of ionization chambers. Methods: Calorimetric absorbed dose to water Dw was measured with a new water calorimeter in the bore of an MRLinac (TPR20,10 of 0.702). Two waterproof ionization chambers (PTW 30013, IBA FC-65G) were calibrated inside the calorimeter phantom (ND,w,Q,B). Both measurements were normalized to a monitor ionization chamber. Ionization chamber measurements were corrected for conventional influence parameter. Based on the chambers’ Co-60 calibrations (ND,w,Q0), measured directly against the calorimeter. In this study the correction factors kQ,B was determined as the ratio of the calibration coefficients in the MRLinac and in Co-60. Additionally, kB was determined based on kQ values obtained with the IAEA TRS-398 Code of Practice. Results: The kQ,B factors of the ionization chambers mentioned above were respectively 0.9488(8) and 0.9445(8) with resulting kB factors of 0.961(13) and 0.952(13) with standard uncertainties on the least significant digit(s) between brackets. Conclusion: Calorimetric Dw measurements and calibration of waterproof ionization chambers were successfully carried out in the 1.5 T B-field of an MRLinac with a standard uncertainty of 0.7%. Preliminary kQ,B and kB factors were determined with standard uncertainties of respectively 0.8% and 1.3%. The kQ,B agrees with an alternative method within 0.4%. The feasibility of water calorimetry in the presence of B

Simultaneous analysis in renormalization and factorization scheme dependences in perturbative QCD

International Nuclear Information System (INIS)

Nakkagawa, Hisao; Niegawa, Akira.

1983-01-01

Combined and thorough investigations of both the factorization and the renormalization scheme dependences of perturbative QCD calculations are given. Our findings are that (i) by introducing a multiscale-dependent coupling the simultaneous parametrization of both scheme-dependences can be accomplished, (ii) Stevenson's optimization method works quite well so that it gives a remarkable prediction which forces us to exponentiate ''everything'' with uncorrected subprocess cross sections, and (iii) the perturbation series in QCD may converge when Stevenson's principle of minimal sensitivity is taken into account at each order of perturbative approximation. (author)

Advantages of using a two-switch forward in single-stage power factor corrected power supplies

DEFF Research Database (Denmark)

Petersen, Lars

2000-01-01

A single-stage power factor corrected power supply using a two-switch forward is proposed to increase efficiency. The converter is operated in the DCM (discontinues conduction mode) and it is shown that this operation mode ensures the intermediate DC-bus to be controlled only by means of circuit...... supply has been implemented. The measured efficiency is between 85% and 88.5% in the range 30 W-500 W and the measured power factor at full load is 0.95....... parameters and therefore independent of load variations. The DCM operation often has a diminishing effect on the efficiency but by use of the two-switch topology high efficiency with minimum circuit complexity can be achieved in this mode. A 500 W 70 V prototype of the two-switch boost-forward PFC power...

THE METALLICITY DEPENDENCE OF THE CO {yields} H{sub 2} CONVERSION FACTOR IN z {>=} 1 STAR-FORMING GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Genzel, R.; Tacconi, L. J.; Schreiber, N. M. Foerster; Gracia-Carpio, J.; Lutz, D.; Saintonge, A. [Max-Planck-Institut fuer extraterrestrische Physik (MPE), Giessenbachstr. 1, 85748 Garching (Germany); Combes, F. [Observatoire de Paris, LERMA, CNRS, 61 Av. de l' Observatoire, F-75014 Paris (France); Bolatto, A. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Neri, R.; Cox, P. [IRAM, 300 Rue de la Piscine, 38406 St. Martin d' Heres, Grenoble (France); Sternberg, A. [Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Cooper, M. C. [Department of Physics and Astronomy, Frederick Reines Hall, University of California, Irvine, CA 92697-4575 (United States); Bouche, N. [Department of Physics, University of California, Santa Barbara, Broida Hall, Santa Barbara, CA 93106 (United States); Bournaud, F. [Service d' Astrophysique, DAPNIA, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex (France); Burkert, A. [Universitaetssternwarte der Ludwig-Maximiliansuniversitaet, Scheinerstr. 1, D-81679 Muenchen (Germany); Comerford, J. [Department of Astronomy and McDonald Observatory, 1 University Station, C1402 Austin, TX 78712-0259 (United States); Davis, M.; Newman, S. [Department of Astronomy, Campbell Hall, University of California, Berkeley, CA 94720 (United States); Garcia-Burillo, S. [Observatorio Astronomico Nacional-OAN, Apartado 1143, 28800 Alcala de Henares- Madrid (Spain); Naab, T., E-mail: genzel@mpe.mpg.de, E-mail: linda@mpe.mpg.de [Max-Planck Institut fuer Astrophysik (MPA), Karl Schwarzschildstrasse 1, D-85748 Garching (Germany); and others

2012-02-10

We use the first systematic samples of CO millimeter emission in z {>=} 1 'main-sequence' star-forming galaxies to study the metallicity dependence of the conversion factor {alpha}{sub CO,} from CO line luminosity to molecular gas mass. The molecular gas depletion rate inferred from the ratio of the star formation rate (SFR) to CO luminosity, is {approx}1 Gyr{sup -1} for near-solar metallicity galaxies with stellar masses above M{sub S} {approx} 10{sup 11} M{sub Sun }. In this regime, the depletion rate does not vary more than a factor of two to three as a function of molecular gas surface density or redshift between z {approx} 0 and 2. Below M{sub S} the depletion rate increases rapidly with decreasing metallicity. We argue that this trend is not caused by starburst events, by changes in the physical parameters of the molecular clouds, or by the impact of the fundamental-metallicity-SFR-stellar mass relation. A more probable explanation is that the conversion factor is metallicity dependent and that star formation can occur in 'CO-dark' gas. The trend is also expected theoretically from the effect of enhanced photodissociation of CO by ultraviolet radiation at low metallicity. From the available z {approx} 0 and z {approx} 1-3 samples we constrain the slope of the log({alpha}{sub CO})-log (metallicity) relation to range between -1 and -2, fairly insensitive to the assumed slope of the gas-SFR relation. Because of the lower metallicities near the peak of the galaxy formation activity at z {approx} 1-2 compared to z {approx} 0, we suggest that molecular gas masses estimated from CO luminosities have to be substantially corrected upward for galaxies below M{sub S}.

Testing effort dependent software reliability model for imperfect debugging process considering both detection and correction

International Nuclear Information System (INIS)

Peng, R.; Li, Y.F.; Zhang, W.J.; Hu, Q.P.

2014-01-01

This paper studies the fault detection process (FDP) and fault correction process (FCP) with the incorporation of testing effort function and imperfect debugging. In order to ensure high reliability, it is essential for software to undergo a testing phase, during which faults can be detected and corrected by debuggers. The testing resource allocation during this phase, which is usually depicted by the testing effort function, considerably influences not only the fault detection rate but also the time to correct a detected fault. In addition, testing is usually far from perfect such that new faults may be introduced. In this paper, we first show how to incorporate testing effort function and fault introduction into FDP and then develop FCP as delayed FDP with a correction effort. Various specific paired FDP and FCP models are obtained based on different assumptions of fault introduction and correction effort. An illustrative example is presented. The optimal release policy under different criteria is also discussed

The Comparative Effect of Online Self-Correction, Peer- correction, and Teacher Correction in Descriptive Writing Tasks on Intermediate EFL Learners’ Grammar Knowledge The Prospect of Mobile Assisted Language Learning (MALL

Directory of Open Access Journals (Sweden)

Mojtaba Aghajani

2018-05-01

Full Text Available 60 participants of the study were selected based on their scores on the Nelson proficiency test and divided into three Telegram groups comprising a peer-correction, a self-correction and a teacher-correction group, each with 20 students. The pretest was administered to measure the subjects' grammar knowledge. Subsequently, three Telegram groups each with 21 members (20 students + 1 teacher were formed. Then during a course of nearly one academic term the grammatical notions were taught by the teacher. The members were required to write on the prompt in about 50 to 70 words and post it on the group. Then, their writings were corrected through self-correction, peer-correction and teacher-correction under the feedback provided by the researcher. The study used a pretest-posttest design to compare the learners’ progress after the application of three different types of treatment. One-Way between-groups ANOVA was run to test whether there was any statistically significant difference in grammar knowledge in descriptive writing of intermediate EFL learners’ who receive mobile-assisted self-correction, peer-correction and teacher-correction. The researcher also used Post-Hoc Tests to determine the exact difference between correction methods. Online self-correction, peer-correction and teacher-correction were the independent variables and grammar knowledge was the dependent variable. Examining the result of the study prove that significance level between self-correction and teacher-correction was the strongest (sig. = 0.000 but the significance level was a little less strong between peer-correction and teacher-correction whereas no significance was observed between self-correction and peer-correction.

Fatores de risco para dependência de álcool em adolescentes Factores de riesgo en adolescentes con dependencia al alcohol Risk factors for alcohol dependence in adolescents

Directory of Open Access Journals (Sweden)

Leandro Rozin

2012-01-01

Full Text Available OBJETIVO: Identificar os fatores de risco para dependência do álcool na adolescência. MÉTODOS: Revisão integrativa com 21 artigos publicados entre 2000 e 2009, capturados nas bases de dados LILACS, BVS, MEDLINE, COCHRANE e IBECS com as palavras-chave: adolescência, risco para dependência e álcool. RESULTADOS: Há evidências de que o álcool é a droga mais consumida por adolescentes, com início entre 14 a 16 anos. Os fatores de risco para dependência estão relacionados ao início precoce do uso, influência da mídia, relacionamento conturbado com os pais, uso por membro da família, abuso sexual, violência doméstica, baixa autoestima, curiosidade, pressão de colegas, entre outros. Apontam a vulnerabilidade genética para a dependência do álcool e controvérsias em relação ao gênero e classe social. CONCLUSÃO: Os serviços de saúde devem incorporar estratégias preventivas de identificação de riscos para a dependência, controle e acompanhamento específicos ao grupo de adolescentes dependentes.OBJETIVO: Identificar los factores de riesgo en adolescentes con dependencia al alcohol. MÉTODOS: Revisión integrativa realizada con 21 artículos publicados entre 2000 y 2009, identificados en las bases de datos LILACS, BVS, MEDLINE, COCHRANE e IBECS con las palabras-clave: adolescencia, riesgo a dependencia y alcohol. RESULTADOS: Hay evidencias de que el alcohol es la droga más consumida por adolescentes, con inicio entre 14 a 16 años. Los factores de riesgo para la dependencia están relacionados al inicio precoz del uso, influencia de los medios de comunicación, relacionamiento conturbado con los padres, uso por un miembro de la familia, abuso sexual, violencia doméstica, baja autoestima, curiosidad, presión de colegas, entre otros. Apuntan la vulnerabilidad genética para la dependencia al alcohol y controversias en relación al género y clase social. CONCLUSIÓN: Los servicios de salud deben incorporar estrategias

A source-independent empirical correction procedure for the fast mobility and engine exhaust particle sizers

Science.gov (United States)

Zimmerman, Naomi; Jeong, Cheol-Heon; Wang, Jonathan M.; Ramos, Manuel; Wallace, James S.; Evans, Greg J.

2015-01-01

The TSI Fast Mobility Particle Sizer (FMPS) and Engine Exhaust Particle Sizer (EEPS) provide size distributions for 6-560 nm particles with a time resolution suitable for characterizing transient particle sources; however, the accuracy of these instruments can be source dependent, due to influences of particle morphology. The aim of this study was to develop a source-independent correction protocol for the FMPS and EEPS. The correction protocol consists of: (1) broadening the >80 nm size range of the distribution to account for under-sizing by the FMPS and EEPS; (2) applying an existing correction protocol in the 8-93 nm size range; and (3) dividing each size bin by the ratio of total concentration measured by the FMPS or EEPS and a water-based Condensation Particle Counter (CPC) as a surrogate scaling factor to account for particle morphology. Efficacy of the correction protocol was assessed for three sources: urban ambient air, diluted gasoline direct injection engine exhaust, and diluted diesel engine exhaust. Linear regression against a reference instrument, the Scanning Mobility Particle Sizer (SMPS), before and after applying the correction protocol demonstrated that the correction ensured agreement within 20%.

Correction factors and performance of a 4 degrees C sealed water calorimeter.

Science.gov (United States)

Seuntjens, J; Palmans, H

1999-03-01

In the past two decades, the water calorimetry technique for determination of absorbed dose to water in several types of radiation beams has moved significantly closer to being a recognized method. In this paper we summarize the constructional details of a 4 degrees C sealed water calorimeter currently in operation at the University of Gent. This sealed water (SW) calorimeter is of the Domen type and has been improved in several aspects compared with its original design. The relevant correction factors for heat transport and for field perturbation are described. Using relative response measurements in 60Co, we experimentally verified the relative heat defect for two distinct chemical systems, using two different detection vessel arrangements. The overall 1sigma uncertainty on the absorbed dose to water at 60Co based on this system amounts to 0.7%.

Spectral correction factors for conventional neutron dose meters used in high-energy neutron environments improved and extended results based on a complete survey of all neutron spectra in IAEA-TRS-403

International Nuclear Information System (INIS)

Oparaji, U.; Tsai, Y. H.; Liu, Y. C.; Lee, K. W.; Patelli, E.; Sheu, R. J.

2017-01-01

This paper presents improved and extended results of our previous study on corrections for conventional neutron dose meters used in environments with high-energy neutrons (E n > 10 MeV). Conventional moderated-type neutron dose meters tend to underestimate the dose contribution of high-energy neutrons because of the opposite trends of dose conversion coefficients and detection efficiencies as the neutron energy increases. A practical correction scheme was proposed based on analysis of hundreds of neutron spectra in the IAEA-TRS-403 report. By comparing 252 Cf-calibrated dose responses with reference values derived from fluence-to-dose conversion coefficients, this study provides recommendations for neutron field characterization and the corresponding dose correction factors. Further sensitivity studies confirm the appropriateness of the proposed scheme and indicate that (1) the spectral correction factors are nearly independent of the selection of three commonly used calibration sources: 252 Cf, 241 Am-Be and 239 Pu-Be; (2) the derived correction factors for Bonner spheres of various sizes (6''-9'') are similar in trend and (3) practical high-energy neutron indexes based on measurements can be established to facilitate the application of these correction factors in workplaces. (authors)

Tissue factor-dependent vascular endothelial growth factor production by human fibroblasts in response to activated factor VII.

Science.gov (United States)

Ollivier, V; Bentolila, S; Chabbat, J; Hakim, J; de Prost, D

1998-04-15

The transmembrane protein tissue factor (TF) is the cell surface receptor for coagulation factor VII (FVII) and activated factor VII (FVIIa). Recently, TF has been identified as a regulator of angiogenesis, tumor growth, and metastasis. This study was designed to link the binding of FVII(a) to its receptor, TF, with the subsequent triggering of angiogenesis through vascular endothelial growth factor (VEGF) production by human lung fibroblasts. We report that incubation of fibroblasts, which express constitutive surface TF, with FVII(a) induces VEGF synthesis. FVII(a)-induced VEGF secretion, assessed by a specific enzyme-linked immunosorbent assay, was time- and concentration-dependent. VEGF secretion was maximal after 24 hours of incubation of the cells with 100 nmol/L FVII(a) and represented a threefold induction of the basal VEGF level. Reverse transcriptase-polymerase chain reaction analysis of VEGF detected three mRNA species of 180, 312, and 384 bp corresponding, respectively, to VEGF121, VEGF165, and VEGF189. A 2.5- to 3.5-fold increase was observed for the 180- and 312-bp transcripts at 12 and 24 hours, respectively. FVII(a)-dependent VEGF production was inhibited by a pool of antibodies against TF, pointing to the involvement of this receptor. On specific active-site inhibition with dansyl-glutamyl-glycinyl-arginyl chloromethyl ketone, FVIIa lost 70% of its capacity to elicit VEGF production. Consistent with this, the native form (zymogen) of FVII only had a 1.8-fold stimulating effect. Protein tyrosine kinase and protein kinase C are involved in signal transduction leading to VEGF production, as shown by the inhibitory effects of genistein and GF 109203X. The results of this study indicate that TF is essential for VIIa-induced VEGF production by human fibroblasts and that its role is mainly linked to the proteolytic activity of the TF-VIIa complex.

Finite-size corrections to the free energies of crystalline solids

NARCIS (Netherlands)

Polson, J.M.; Trizac, E.; Pronk, S.; Frenkel, D.

2000-01-01

We analyze the finite-size corrections to the free energy of crystals with a fixed center of mass. When we explicitly correct for the leading (ln N/N) corrections, the remaining free energy is found to depend linearly on 1/N. Extrapolating to the thermodynamic limit (N → ∞), we estimate the free

First positive reactions to cannabis constitute a priority risk factor for cannabis dependence.

Science.gov (United States)

Le Strat, Yann; Ramoz, Nicolas; Horwood, John; Falissard, Bruno; Hassler, Christine; Romo, Lucia; Choquet, Marie; Fergusson, David; Gorwood, Philip

2009-10-01

To assess the association between first reactions to cannabis and the risk of cannabis dependence. A cross-sectional population-based assessment in 2007. A campus in a French region (Champagne-Ardennes). A total of 1472 participants aged 18-21 years who reported at least one life-time cannabis consumption, of 3056 students who were screened initially [the Susceptibility Addiction Gene Environment (SAGE) study]. Positive and negative effects of first cannabis consumptions, present cannabis dependence and related risk factors were assessed through questionnaires.   The effects of first cannabis consumptions were associated dose-dependently with cannabis dependence at age 18-21 years, both according to the transversal approach of the SAGE study and to the prospective cohort of the Christchurch Health and Development Study (CHDS) assessed at the age of 25 years. Participants of the SAGE study who reported five positive effects of their first cannabis consumption had odds of life-time cannabis dependence that were 28.7 (95% confidence interval: 14.6-56.5) higher than those who reported no positive effects. This association remains significant after controlling for potentially confounding factors, including individual and familial variables. This study suggests an association between positive reactions to first cannabis uses and risk of life-time cannabis dependence, this variable having a central role among, and through, other risk factors. © 2009 The Authors. Journal compilation © 2009 Society for the Study of Addiction.

Method for determining correction factors induced by irradiation of ionization chamber cables in large radiation field

International Nuclear Information System (INIS)

Rodrigues, L.L.C.

1988-01-01

A simple method was developed to be suggested to hospital physicists in order to be followed during large radiation field dosimetry, to evaluate the effects of cables, connectors and extension cables irradiation and to determine correction factors for each system or geometry. All quality control tests were performed according to the International Electrotechnical Commission for three clinical dosimeters. Photon and electron irradiation effects for cables, connectors and extention cables were investigated under different experimental conditions by means of measurements of chamber sensitivity to a standard radiation source of 90 Sr. The radiation induced leakage current was also measured for cables, connectors and extension cables irradiated by photons and electrons. All measurements were performed at standard dosimetry conditions. Finally, measurements were performed in large fields. Cable factors and leakage factors were determined by the relation between chamber responses for irradiated and unirradiated cables. (author) [pt

Power corrections and renormalons in Transverse Momentum Distributions

Energy Technology Data Exchange (ETDEWEB)

Scimemi, Ignazio [Departamento de Física Teórica II, Universidad Complutense de Madrid,Ciudad Universitaria, 28040 Madrid (Spain); Vladimirov, Alexey [Institut für Theoretische Physik, Universität Regensburg,D-93040 Regensburg (Germany)

2017-03-01

We study the power corrections to Transverse Momentum Distributions (TMDs) by analyzing renormalon divergences of the perturbative series. The renormalon divergences arise independently in two constituents of TMDs: the rapidity evolution kernel and the small-b matching coefficient. The renormalon contributions (and consequently power corrections and non-perturbative corrections to the related cross sections) have a non-trivial dependence on the Bjorken variable and the transverse distance. We discuss the consistency requirements for power corrections for TMDs and suggest inputs for the TMD phenomenology in accordance with this study. Both unpolarized quark TMD parton distribution function and fragmentation function are considered.

A hybrid filter to mitigate harmonics caused by nonlinear load and resonance caused by power factor correction capacitor

Science.gov (United States)

Adan, N. F.; Soomro, D. M.

2017-01-01

Power factor correction capacitor (PFCC) is commonly installed in industrial applications for power factor correction (PFC). With the expanding use of non-linear equipment such as ASDs, power converters, etc., power factor (PF) improvement has become difficult due to the presence of harmonics. The resulting capacitive impedance of the PFCC may form a resonant circuit with the source inductive reactance at a certain frequency, which is likely to coincide with one of the harmonic frequency of the load. This condition will trigger large oscillatory currents and voltages that may stress the insulation and cause subsequent damage to the PFCC and equipment connected to the power system (PS). Besides, high PF cannot be achieved due to power distortion. This paper presents the design of a three-phase hybrid filter consisting of a single tuned passive filter (STPF) and shunt active power filter (SAPF) to mitigate harmonics and resonance in the PS through simulation using PSCAD/EMTDC software. SAPF was developed using p-q theory. The hybrid filter has resulted in significant improvement on both total harmonic distortion for voltage (THDV) and total demand distortion for current (TDDI) with maximum values of 2.93% and 9.84% respectively which were within the recommended IEEE 519-2014 standard limits. Regarding PF improvement, the combined filters have achieved PF close to desired PF at 0.95 for firing angle, α values up to 40°.

Pairing correction of particle-hole state densities for two kinds of Fermions

International Nuclear Information System (INIS)

Fu, C.Y.

1985-01-01

Pairing corrections in particle-hole (exciton) state-density formulas used in precompound nuclear reaction theories are, strictly speaking, dependent on the nuclear excitation energy U and the exciton number n. A general formula for (U,n)-dependent pairing corrections has been derived in an earlier paper for exciton state-density formulas for one kind of Fermion. In the present paper, a similar derivation is made for two kinds of Fermions. It is shown that the constant-pairing-energy correction used in standard level-density formulas, such as U 0 in Gilbert and Cameron, is a limiting case of the present general (U,n)-dependent results

SU-E-T-644: Evaluation of Angular Dependence Correction for 2D Array Detector Using for Quality Assurance of Volumetric Modulated Arc Therapy

International Nuclear Information System (INIS)

Karthikeyan, N; Ganesh, K M; Vikraman, S; Shariff, MH

2014-01-01

Purpose: To evaluate the angular dependence correction for Matrix Evolution 2D array detector in quality assurance of volumetric modulated arc therapy(VMAT). Methods: Total ten patients comprising of different sites were planned for VMAT and taken for the study. Each plan was exposed on Matrix Evolution 2D array detector with Omnipro IMRT software based on the following three different methods using 6MV photon beams from Elekta Synergy linear accelerator. First method, VMAT plan was delivered on Matrix Evolution detector as it gantry mounted with dedicated holder with build-up of 2.3cm. Second, the VMAT plan was delivered with the static gantry angle on to the table mounted setup. Third, the VMAT plan was delivered with actual gantry angle on Matrix Evolution detector fixed in Multicube phantom with gantry angle sensor and angular dependence correction were applied to quantify the plan quality. For all these methods, the corresponding QA plans were generated in TPS and the dose verification was done for both point and 2D fluence analysis with pass criteria of 3% dose difference and 3mm distance to agreement. Results: The measured point dose variation for the first method was observed as 1.58±0.6% of mean and SD with TPS calculated. For second and third method, the mean and standard deviation(SD) was observed as 1.67±0.7% and 1.85±0.8% respectively. The 2D fluence analysis of measured and TPS calculated has the mean and SD of 97.9±1.1%, 97.88±1.2% and 97.55±1.3% for first, second and third methods respectively. The calculated two-tailed Pvalue for point dose and 2D fluence analysis shows the insignificance with values of 0.9316 and 0.9015 respectively, among the different methods of QA. Conclusion: The qualitative evaluation of angular dependence correction for Matrix Evolution 2D array detector shows its competency in accuracy of quality assurance measurement of composite dose distribution of volumetric modulated arc therapy

Markov model of the loan portfolio dynamics considering influence of management and external economic factors

Science.gov (United States)

Bozhalkina, Yana; Timofeeva, Galina

2016-12-01

Mathematical model of loan portfolio in the form of a controlled Markov chain with discrete time is considered. It is assumed that coefficients of migration matrix depend on corrective actions and external factors. Corrective actions include process of receiving applications, interaction with existing solvent and insolvent clients. External factors are macroeconomic indicators, such as inflation and unemployment rates, exchange rates, consumer price indices, etc. Changes in corrective actions adjust the intensity of transitions in the migration matrix. The mathematical model for forecasting the credit portfolio structure taking into account a cumulative impact of internal and external changes is obtained.

Surgical correction of postoperative astigmatism

Directory of Open Access Journals (Sweden)

Lindstrom Richard

1990-01-01

Full Text Available The photokeratoscope has increased the understanding of the aspheric nature of the cornea as well as a better understanding of normal corneal topography. This has significantly affected the development of newer and more predictable models of surgical astigmatic correction. Relaxing incisions effectively flatten the steeper meridian an equivalent amount as they steepen the flatter meridian. The net change in spherical equivalent is, therefore, negligible. Poor predictability is the major limitation of relaxing incisions. Wedge resection can correct large degrees of postkeratoplasty astigmatism, Resection of 0.10 mm of tissue results in approximately 2 diopters of astigmatic correction. Prolonged postoperative rehabilitation and induced irregular astigmatism are limitations of the procedure. Transverse incisions flatten the steeper meridian an equivalent amount as they steepen the flatter meridian. Semiradial incisions result in two times the amount of flattening in the meridian of the incision compared to the meridian 90 degrees away. Combination of transverse incisions with semiradial incisions describes the trapezoidal astigmatic keratotomy. This procedure may correct from 5.5 to 11.0 diopters dependent upon the age of the patient. The use of the surgical keratometer is helpful in assessing a proper endpoint during surgical correction of astigmatism.

A temperature dependent slip factor based thermal model for friction

Indian Academy of Sciences (India)

This paper proposes a new slip factor based three-dimensional thermal model to predict the temperature distribution during friction stir welding of 304L stainless steel plates. The proposed model employs temperature and radius dependent heat source to study the thermal cycle, temperature distribution, power required, the ...

Mass number dependence of total neutron cross section; a discussion based on the semi-classical optical model

International Nuclear Information System (INIS)

Angeli, Istvan

1990-01-01

The dependence of total neutron cross section on mass number can be calculated by the black nucleus formula, according to the optical model. The fine structure of mass number dependence is studied, and a correction factor formula is given on the basis of a semi-classical optical model. Yielding results in good agreement with experimental data. In addition to the mass number dependence, the neutron-energy dependence can also be calculated using this model. (K.A.)

Bronchopulmonary dysplasia as a predictor factor for motor alteration at 6 months corrected age in premature infants

OpenAIRE

Martins,Priscila Silveira; Mello,Rosane Reis de; Silva,Kátia Silveira da

2010-01-01

OBJECTIVE: The study aimed to assess bronchopulmonary dysplasia (BPD) as a predisposing factor for alteration in the psychomotor development index (PDI) in premature infants and verify the incidence of neuromotor alterations at 6 months corrected age. METHOD: This was a prospective cohort study that followed the neuromotor development of 152 very low birth weight premature infants, with psychomotor development index as the outcome. The study used the Bayley Scale of Infant Development at 6 mo...

Generalized radiative corrections for hadronic targets

International Nuclear Information System (INIS)

Calan, C. de; Navelet, H.; Picard, J.

1990-02-01

Besides the radiative corrections theory at the order α 2 for reactions involving an arbitrary number of particles, this report gives the complete formula for the correction factor δ in dσ = dσ Born (1 + δ). The only approximation made here - unavoidable in this formulation - is to assume that the Born amplitude can be factorized. This calculation is valid for spin zero bosons. In the 1/2 fermion case, an extra contribution appears which has been analytically computed using a minor approximation. Special care has been devoted to the 1/v divergence of the amplitude near thresholds [fr

High order corrections to the renormalon

International Nuclear Information System (INIS)

Faleev, S.V.

1997-01-01

High order corrections to the renormalon are considered. Each new type of insertion into the renormalon chain of graphs generates a correction to the asymptotics of perturbation theory of the order of ∝1. However, this series of corrections to the asymptotics is not the asymptotic one (i.e. the mth correction does not grow like m.). The summation of these corrections for the UV renormalon may change the asymptotics by a factor N δ . For the traditional IR renormalon the mth correction diverges like (-2) m . However, this divergence has no infrared origin and may be removed by a proper redefinition of the IR renormalon. On the other hand, for IR renormalons in hadronic event shapes one should naturally expect these multiloop contributions to decrease like (-2) -m . Some problems expected upon reaching the best accuracy of perturbative QCD are also discussed. (orig.)

Power corrections to exclusive processes in QCD

Energy Technology Data Exchange (ETDEWEB)

Mankiewicz, Lech

2002-02-01

In practice applicability of twist expansion crucially depends on the magnitude to power corrections to the leading-twist amplitude. I illustrate this point by considering explicit examples of two hard exclusive processes in QCD. In the case of {gamma}{sup *}{gamma} {yields} {pi}{pi} amplitude power corrections are small enough such that it should be possible to describe current experimental data by the leading-twist QCD prediction. The photon helicity-flip amplitude in DVCS on a nucleon receives large kinematical power corrections which screen the leading-twist prediction up to large values of the hard photon virtuality.

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

Energy Technology Data Exchange (ETDEWEB)

Young, M.; Antonarakis, S.E. [Univ. of Geneva (Switzerland); Inaba, Hiroshi [Tokyo Medical College (Japan)] [and others

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.

Automatic color preference correction for color reproduction

Science.gov (United States)

Tsukada, Masato; Funayama, Chisato; Tajima, Johji

2000-12-01

The reproduction of natural objects in color images has attracted a great deal of attention. Reproduction more pleasing colors of natural objects is one of the methods available to improve image quality. We developed an automatic color correction method to maintain preferred color reproduction for three significant categories: facial skin color, green grass and blue sky. In this method, a representative color in an object area to be corrected is automatically extracted from an input image, and a set of color correction parameters is selected depending on the representative color. The improvement in image quality for reproductions of natural image was more than 93 percent in subjective experiments. These results show the usefulness of our automatic color correction method for the reproduction of preferred colors.

Monte Carlo computed machine-specific correction factors for reference dosimetry of TomoTherapy static beam for several ion chambers

International Nuclear Information System (INIS)

Sterpin, E.; Mackie, T. R.; Vynckier, S.

2012-01-01

Purpose: To determine k Q msr ,Q o f msr ,f 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 Q msr ,Q o f msr ,f o for reference dosimetry, applicable to static TomoTherapy beams. In this study, those factors were computed directly using MC simulations for Q 0 corresponding to a simplified 60 Co beam in TRS-398 reference conditions (at 10 cm depth). The msr conditions were a 10 × 5 cm 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 c hamber user code. Phase-space files used as the source input were produced using PENELOPE after simulation of a simplified 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 Q msr ,Q o f msr ,f 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 20,10 for a 6 MV Elekta photon beam (0.661), the additional correction k Q msr, Q f msr, f ref to k Q,Q 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

Gamma ray auto absorption correction evaluation methodology

International Nuclear Information System (INIS)

Gugiu, Daniela; Roth, Csaba; Ghinescu, Alecse

2010-01-01

Neutron activation analysis (NAA) is a well established nuclear technique, suited to investigate the microstructural or elemental composition and can be applied to studies of a large variety of samples. The work with large samples involves, beside the development of large irradiation devices with well know neutron field characteristics, the knowledge of perturbing phenomena and adequate evaluation of correction factors like: neutron self shielding, extended source correction, gamma ray auto absorption. The objective of the works presented in this paper is to validate an appropriate methodology for gamma ray auto absorption correction evaluation for large inhomogeneous samples. For this purpose a benchmark experiment has been defined - a simple gamma ray transmission experiment, easy to be reproduced. The gamma ray attenuation in pottery samples has been measured and computed using MCNP5 code. The results show a good agreement between the computed and measured values, proving that the proposed methodology is able to evaluate the correction factors. (authors)

Adaptive topographic mass correction for satellite gravity and gravity gradient data

Science.gov (United States)

Holzrichter, Nils; Szwillus, Wolfgang; Götze, Hans-Jürgen

2014-05-01

Subsurface modelling with gravity data includes a reliable topographic mass correction. Since decades, this mandatory step is a standard procedure. However, originally methods were developed for local terrestrial surveys. Therefore, these methods often include defaults like a limited correction area of 167 km around an observation point, resampling topography depending on the distance to the station or disregard the curvature of the earth. New satellite gravity data (e.g. GOCE) can be used for large scale lithospheric modelling with gravity data. The investigation areas can include thousands of kilometres. In addition, measurements are located in the flight height of the satellite (e.g. ~250 km for GOCE). The standard definition of the correction area and the specific grid spacing around an observation point was not developed for stations located in these heights and areas of these dimensions. This asks for a revaluation of the defaults used for topographic correction. We developed an algorithm which resamples the topography based on an adaptive approach. Instead of resampling topography depending on the distance to the station, the grids will be resampled depending on its influence at the station. Therefore, the only value the user has to define is the desired accuracy of the topographic correction. It is not necessary to define the grid spacing and a limited correction area. Furthermore, the algorithm calculates the topographic mass response with a spherical shaped polyhedral body. We show examples for local and global gravity datasets and compare the results of the topographic mass correction to existing approaches. We provide suggestions how satellite gravity and gradient data should be corrected.

Gamma-ray self-attenuation corrections in environmental samples

International Nuclear Information System (INIS)

Robu, E.; Giovani, C.

2009-01-01

Gamma-spectrometry is a commonly used technique in environmental radioactivity monitoring. Frequently the bulk samples that should be measured differ with respect to composition and density from the reference sample used for efficiency calibration. Correction factors should be applied in these cases for activity measurement. Linear attenuation coefficients and self-absorption correction factors have been evaluated for soil, grass and liquid sources with different densities and geometries.(authors)

The mean photon energy anti E{sub F} at the point of measurement determines the detector-specific radiation quality correction factor k{sub Q,M} in {sup 192}Ir brachytherapy dosimetry

Energy Technology Data Exchange (ETDEWEB)

Chofor, Ndimofor; Harder, Dietrich; Selbach, Hans-Joachim; Poppe, Bjoern [University of Oldenburg and Pius-Hospital Oldenburg (Germany). Medical Radiation Physics Group

2016-11-01

The application of various radiation detectors for brachytherapy dosimetry has motivated this study of the energy dependence of radiation quality correction factor k{sub Q,M}, the quotient of the detector responses under calibration conditions at a {sup 60}Co unit and under the given non-reference conditions at the point of measurement, M, occurring in photon brachytherapy. The investigated detectors comprise TLD, radiochromic film, ESR, Si diode, plastic scintillator and diamond crystal detectors as well as ionization chambers of various sizes, whose measured response-energy relationships, taken from the literature, served as input data. Brachytherapy photon fields were Monte-Carlo simulated for an ideal isotropic {sup 192}Ir point source, a model spherical {sup 192}Ir source with steel encapsulation and a commercial HDR GammaMed Plus source. The radial source distance was varied within cylindrical water phantoms with outer radii ranging from 10 to 30 cm and heights from 20 to 60 cm. By application of this semiempirical method - originally developed for teletherapy dosimetry - it has been shown that factor k{sub Q,M} is closely correlated with a single variable, the fluence-weighted mean photon energy anti E{sub F} at the point of measurement. The radial profiles of anti E{sub F} obtained with either the commercial {sup 192}Ir source or the two simplified source variants show little variation. The observed correlations between parameters k{sub Q,M} and anti E{sub F} are represented by fitting formulae for all investigated detectors, and further variation of the detector type is foreseen. The herewith established close correlation of radiation quality correction factor k{sub Q,M} with local mean photon energy anti E{sub F} can be regarded as a simple regularity, facilitating the practical application of correction factor k{sub Q,M} for in-phantom dosimetry around {sup 192}Ir brachytherapy sources. anti E{sub F} values can be assessed by Monte Carlo simulation or

Kernel parameter dependence in spatial factor analysis

DEFF Research Database (Denmark)

Nielsen, Allan Aasbjerg

2010-01-01

kernel PCA. Shawe-Taylor and Cristianini [4] is an excellent reference for kernel methods in general. Bishop [5] and Press et al. [6] describe kernel methods among many other subjects. The kernel version of PCA handles nonlinearities by implicitly transforming data into high (even infinite) dimensional...... feature space via the kernel function and then performing a linear analysis in that space. In this paper we shall apply a kernel version of maximum autocorrelation factor (MAF) [7, 8] analysis to irregularly sampled stream sediment geochemistry data from South Greenland and illustrate the dependence...... of the kernel width. The 2,097 samples each covering on average 5 km2 are analyzed chemically for the content of 41 elements....

SELF CORRECTION WORKS BETTER THAN TEACHER CORRECTION IN EFL SETTING

Directory of Open Access Journals (Sweden)

Azizollah Dabaghi

2012-11-01

Full Text Available Learning a foreign language takes place step by step, during which mistakes are to be expected in all stages of learning. EFL learners are usually afraid of making mistakes which prevents them from being receptive and responsive. Overcoming fear of mistakes depends on the way mistakes are rectified. It is believed that autonomy and learner-centeredness suggest that in some settings learner's self-correction of mistakes might be more beneficial for language learning than teacher's correction. This assumption has been the subject of debates for some time. Some researchers believe that correction whether that of teacher's or on behalf of learners is effective in showing them how their current interlanguage differs from the target (Long &Robinson, 1998. Others suggest that correcting the students whether directly or through recasts are ambiguous and may be perceived by the learner as confirmation of meaning rather than feedback on form (Lyster, 1998a. This study is intended to investigate the effects of correction on Iranian intermediate EFL learners' writing composition in Payam Noor University. For this purpose, 90 English majoring students, studying at Isfahan Payam Noor University were invited to participate at the experiment. They all received a sample of TOFEL test and a total number of 60 participants whose scores were within the range of one standard deviation below and above the mean were divided into two equal groups; experimental and control. The experimental group went through some correction during the experiment while the control group remained intact and the ordinary processes of teaching went on. Each group received twelve sessions of two hour classes every week on advanced writing course in which some activities of Modern English (II were selected. Then after the treatment both groups received an immediate test as post-test and the experimental group took the second post-test as the delayed recall test with the same design as the

Electroweak one-loop corrections to the decay of the charged vector boson

International Nuclear Information System (INIS)

Bardin, D.Yu.; Riemann, S.; Riemann, T.

1986-01-01

The electroweak radiative corrections to the decay widths of the W-boson, GITA(W → lanti v, anti ud, anti cs), have been calculated in the standard theory. The results are presented in terms of an electroweak form factor rhosup(W), and their dependence on msub(t) and Msub(Hsub(W)) (masses of t-quark and higgs boson) is studied. Typically value of rhosup(W)-1 is of an order of one per cent. The difference rhosub(qq')sup(W) is negligible, 0.045%. The calculational scheme used is described in detail

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

Tomomi Higashide

Full Text Available 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.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.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.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.

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

Science.gov (United States)

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

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. 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. 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. 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.

Image correction for computed tomography to remove crosstalk artifacts

International Nuclear Information System (INIS)

King, K.F.

1990-01-01

A correction method and apparatus for Computed Tomography (CT) which removes ring and streak artifacts from images by correcting for data contamination by crosstalk errors comprises subtracting from the output S o of a detector, a crosstalk factor derived from outputs of adjacent detectors. The crosstalk factors are obtained by scanning an off-centre phantom. (author)

The effective family and personality factors on felony in adolescent felons of Khorramabad house of correction

Directory of Open Access Journals (Sweden)

mandana Saki

2009-04-01

Full Text Available Background: Social damage is one of the problems which destroys the active manpower and young population in the country and also prevents social development. Family is the first environment in which social ground for the child is provided.Any dispute, controversy or inferiority complex in the family may lead to wrong doings The present study aims at the effective family and personality factors on felony in felon adolescents kept in Khorramabad bouse of correction. Materials and Methods: This descriptive- analytic study was carried out on all of the adolescents in Khorramabad house of correction as case group selected using census random sampling and high school students as control group selected by cluster random sampling. Data gathering tool was a 2-part questionnaire including demographic information and standard SCL 90 questionnaire. Results: Results showed that there is a significant relationship between the place of residence, failure in school program, economic status of the family, parents presence, fathers job and education, mothers job and education, parents inter personal relationship and family conflicting. The results also showed that aggression, anxiety, depression, somatic complain, obsessive compulsive, inter personality sensitivity, Psychotic, paranoid and phobia had a significant difference in the case and control groups. Conclusion: Regarding the fact that family environment is considered as the most important educative factor and no social damage has not occurred out of family influence, so no society can claim to be healthy unless to have healthy families.

Superstring threshold corrections to Yukawa couplings

International Nuclear Information System (INIS)

Antoniadis, I.; Taylor, T.R.

1992-12-01

A general method of computing string corrections to the Kaehler metric and Yukawa couplings is developed at the one-loop level for a general compactification of the heterotic superstring theory. It also provides a direct determination of the so-called Green-Schwarz term. The matter metric has an infrared divergent part which reproduces the field-theoretical anomalous dimensions, and a moduli-dependent part which gives rise to threshold corrections in the physical Yukawa couplings. Explicit expressions are derived for symmetric orbifold compactifications. (author). 20 refs

Evaluation of relative radiometric correction techniques on Landsat 8 OLI sensor data

Science.gov (United States)

Novelli, Antonio; Caradonna, Grazia; Tarantino, Eufemia

2016-08-01

The quality of information derived from processed remotely sensed data may depend upon many factors, mostly related to the extent data acquisition is influenced by atmospheric conditions, topographic effects, sun angle and so on. The goal of radiometric corrections is to reduce such effects in order enhance the performance of change detection analysis. There are two approaches to radiometric correction: absolute and relative calibrations. Due to the large amount of free data products available, absolute radiometric calibration techniques may be time consuming and financially expensive because of the necessary inputs for absolute calibration models (often these data are not available and can be difficult to obtain). The relative approach to radiometric correction, known as relative radiometric normalization, is preferred with some research topics because no in situ ancillary data, at the time of satellite overpasses, are required. In this study we evaluated three well known relative radiometric correction techniques using two Landsat 8 - OLI scenes over a subset area of the Apulia Region (southern Italy): the IR-MAD (Iteratively Reweighted Multivariate Alteration Detection), the HM (Histogram Matching) and the DOS (Dark Object Subtraction). IR-MAD results were statistically assessed within a territory with an extremely heterogeneous landscape and all computations performed in a Matlab environment. The panchromatic and thermal bands were excluded from the comparisons.

Correction factors to convert microdosimetry measurements in silicon to tissue in 12C ion therapy.

Science.gov (United States)

Bolst, David; Guatelli, Susanna; Tran, Linh T; Chartier, Lachlan; Lerch, Michael L F; Matsufuji, Naruhiro; Rosenfeld, Anatoly B

2017-03-21

Silicon microdosimetry is a promising technology for heavy ion therapy (HIT) quality assurance, because of its sub-mm spatial resolution and capability to determine radiation effects at a cellular level in a mixed radiation field. A drawback of silicon is not being tissue-equivalent, thus the need to convert the detector response obtained in silicon to tissue. This paper presents a method for converting silicon microdosimetric spectra to tissue for a therapeutic 12 C beam, based on Monte Carlo simulations. The energy deposition spectra in a 10 μm sized silicon cylindrical sensitive volume (SV) were found to be equivalent to those measured in a tissue SV, with the same shape, but with dimensions scaled by a factor κ equal to 0.57 and 0.54 for muscle and water, respectively. A low energy correction factor was determined to account for the enhanced response in silicon at low energy depositions, produced by electrons. The concept of the mean path length [Formula: see text] to calculate the lineal energy was introduced as an alternative to the mean chord length [Formula: see text] because it was found that adopting Cauchy's formula for the [Formula: see text] was not appropriate for the radiation field typical of HIT as it is very directional. [Formula: see text] can be determined based on the peak of the lineal energy distribution produced by the incident carbon beam. Furthermore it was demonstrated that the thickness of the SV along the direction of the incident 12 C ion beam can be adopted as [Formula: see text]. The tissue equivalence conversion method and [Formula: see text] were adopted to determine the RBE 10 , calculated using a modified microdosimetric kinetic model, applied to the microdosimetric spectra resulting from the simulation study. Comparison of the RBE 10 along the Bragg peak to experimental TEPC measurements at HIMAC, NIRS, showed good agreement. Such agreement demonstrates the validity of the developed tissue equivalence correction factors and of

Multi-site Field Verification of Laboratory Derived FDOM Sensor Corrections: The Good, the Bad and the Ugly

Science.gov (United States)

Saraceno, J.; Shanley, J. B.; Aulenbach, B. T.

2014-12-01

Fluorescent dissolved organic matter (FDOM) is an excellent proxy for dissolved organic carbon (DOC) in natural waters. Through this relationship, in situ FDOM can be utilized to capture both high frequency time series and long term fluxes of DOC in small streams. However, in order to calculate accurate DOC fluxes for comparison across sites, in situ FDOM data must be compensated for matrix effects. Key matrix effects, include temperature, turbidity and the inner filter effect due to color. These interferences must be compensated for to develop a reasonable relationship between FDOM and DOC. In this study, we applied laboratory-derived correction factors to real time data from the five USGS WEBB headwater streams in order to gauge their effectiveness across a range of matrix effects. The good news is that laboratory derived correction factors improved the predicative relationship (higher r2) between DOC and FDOM when compared to uncorrected data. The relative importance of each matrix effect (i.e. temperature) varied by site and by time, implying that each and every matrix effect should be compensated for when available. In general, temperature effects were more important on longer time scales, while corrections for turbidity and DOC inner filter effects were most prevalent during hydrologic events, when the highest instantaneous flux of DOC occurred. Unfortunately, even when corrected for matrix effects, in situ FDOM is a weaker predictor of DOC than A254, a common surrogate for DOC, implying that either DOC fluoresces at varying degrees (but should average out over time), that some matrix effects (e.g. pH) are either unaccounted for or laboratory-derived correction factors do not encompass the site variability of particles and organics. The least impressive finding is that the inherent dependence on three variables in the FDOM correction algorithm increases the likelihood of record data gaps which increases the uncertainty in calculated DOC flux values.

[Possible complications of orthokeratology in myopia correction].

Science.gov (United States)

Borodina, N V; Musaeva, G M; Kobzova, M V

2011-01-01

Clinical cases representing complications (refractive, infectious and trophic) of orthokeratologic lenses (OKL) use are described. These clinical cases show that complications of OKL use can be both similar to those of routine contact correction and caused by features of mechanism of corneal refraction change as a result of OKL wear. In our opinion efficacy and safety of this option is directly depends on the correct lens fitting, patient's compliance and regular monitoring of corneal changes.

Isospin asymmetry dependence of the α spectroscopic factor for heavy nuclei

International Nuclear Information System (INIS)

Seif, W. M.; Shalaby, M.; Alrakshy, M. F.

2011-01-01

Both the valence nucleons (holes) and the isospin asymmetry dependencies of the preformation probability of an α-cluster inside parents radioactive nuclei are investigated. The calculations are employed in the framework of the density-dependent cluster model of an α-decay process for the even-even spherical parents nuclei with protons number around the closed shell Z 0 = 82 and neutrons number around the closed shells Z 0 = 82 and Z 0 = 126. The microscopic α-daughter nuclear interaction potential is calculated in the framework of the Hamiltonian energy density approach based on the SLy4 Skyrme-like effective interaction. Also, the calculations based on the realistic effective M3Y-Paris nucleon-nucleon force have been used to confirm the results. The calculations then proceed to find the assault frequency and the α penetration probability within the WKB approximation. The half-lives of the different mentioned α decays are then determined and have been used in turn to find the α spectroscopic factor. We found that the spectroscopic factor increases with increasing the isospin asymmetry of the parent nuclei if they have valence protons and neutrons. When the parent nuclei have neutron or proton holes in addition to the valence protons or neutrons, then the spectroscopic factor is found to decrease with increasing isospin asymmetry. The obtained results show also that the deduced spectroscopic factors follow individual linear behaviors as a function of the multiplication of the valence proton (N p ) and neutron (N n ) numbers. These linear dependencies are correlated with the closed shells core (Z 0 ,N 0 ). The same individual linear behaviors are obtained as a function of the multiplication of N p N n and the isospin asymmetry parameter, N p N n I. Moreover, the whole deduced spectroscopic factors are found to exhibit a nearly general linear trend with the function N p N n /(Z 0 +N 0 ).

Diffractive corrections to the muon Bremsstrahlung

International Nuclear Information System (INIS)

Kel'ner, S.R.; Fedotov, A.M.

1999-01-01

The corrections to the muon Bremsstrahlung cross section due to diffraction of hard photons on nuclei are obtained. In this process the momentum is transmitted to a nucleus not by a charged particle but by the photon the interaction of which with the nucleus can be considered as diffraction on weakly absorbing ball. The amplitude of the process interferes with the usual Bremsstrahlung amplitude, therefore in the cross section together with the diffraction correction the interference term also appears, possessing different sings for μ + and μ - . The photon emission cross section also depends on the sing of muon charge and for muon energy about 10 TeV the difference between the cross section may reach 10%. The corrections to the radiation energy loss are also calculated [ru

Author Correction: Time-dependent memory transformation along the hippocampal anterior-posterior axis.

Science.gov (United States)

Dandolo, Lisa C; Schwabe, Lars

2018-05-24

In the originally published version of this Article, the rightmost graph in Fig. 2c was inadvertently replaced with a duplicate of the central panel. This has now been corrected in both the PDF and HTML versions of the Article.

NNLO QCD corrections to jet production at hadron colliders from gluon scattering

International Nuclear Information System (INIS)

Currie, James; Ridder, Aude Gehrmann-De; Glover, E.W.N.; Pires, João

2014-01-01

We present the next-to-next-to-leading order (NNLO) QCD corrections to dijet production in the purely gluonic channel retaining the full dependence on the number of colours. The sub-leading colour contribution in this channel first appears at NNLO and increases the NNLO correction by around 10% and exhibits a p T dependence, rising from 8% at low p T to 15% at high p T . The present calculation demonstrates the utility of the antenna subtraction method for computing the full colour NNLO corrections to dijet production at the Large Hadron Collider

State-dependent neutral delay equations from population dynamics.

Science.gov (United States)

Barbarossa, M V; Hadeler, K P; Kuttler, C

2014-10-01

A novel class of state-dependent delay equations is derived from the balance laws of age-structured population dynamics, assuming that birth rates and death rates, as functions of age, are piece-wise constant and that the length of the juvenile phase depends on the total adult population size. The resulting class of equations includes also neutral delay equations. All these equations are very different from the standard delay equations with state-dependent delay since the balance laws require non-linear correction factors. These equations can be written as systems for two variables consisting of an ordinary differential equation (ODE) and a generalized shift, a form suitable for numerical calculations. It is shown that the neutral equation (and the corresponding ODE--shift system) is a limiting case of a system of two standard delay equations.

Task-dependent vestibular feedback responses in reaching.

Science.gov (United States)

Keyser, Johannes; Medendorp, W Pieter; Selen, Luc P J

2017-07-01

When reaching for an earth-fixed object during self-rotation, the motor system should appropriately integrate vestibular signals and sensory predictions to compensate for the intervening motion and its induced inertial forces. While it is well established that this integration occurs rapidly, it is unknown whether vestibular feedback is specifically processed dependent on the behavioral goal. Here, we studied whether vestibular signals evoke fixed responses with the aim to preserve the hand trajectory in space or are processed more flexibly, correcting trajectories only in task-relevant spatial dimensions. We used galvanic vestibular stimulation to perturb reaching movements toward a narrow or a wide target. Results show that the same vestibular stimulation led to smaller trajectory corrections to the wide than the narrow target. We interpret this reduced compensation as a task-dependent modulation of vestibular feedback responses, tuned to minimally intervene with the task-irrelevant dimension of the reach. These task-dependent vestibular feedback corrections are in accordance with a central prediction of optimal feedback control theory and mirror the sophistication seen in feedback responses to mechanical and visual perturbations of the upper limb. NEW & NOTEWORTHY Correcting limb movements for external perturbations is a hallmark of flexible sensorimotor behavior. While visual and mechanical perturbations are corrected in a task-dependent manner, it is unclear whether a vestibular perturbation, naturally arising when the body moves, is selectively processed in reach control. We show, using galvanic vestibular stimulation, that reach corrections to vestibular perturbations are task dependent, consistent with a prediction of optimal feedback control theory. Copyright © 2017 the American Physiological Society.

Remote Sensing of Tropical Ecosystems: Atmospheric Correction and Cloud Masking Matter

Science.gov (United States)

Hilker, Thomas; Lyapustin, Alexei I.; Tucker, Compton J.; Sellers, Piers J.; Hall, Forrest G.; Wang, Yujie

2012-01-01

Tropical rainforests are significant contributors to the global cycles of energy, water and carbon. As a result, monitoring of the vegetation status over regions such as Amazonia has been a long standing interest of Earth scientists trying to determine the effect of climate change and anthropogenic disturbance on the tropical ecosystems and its feedback on the Earth's climate. Satellite-based remote sensing is the only practical approach for observing the vegetation dynamics of regions like the Amazon over useful spatial and temporal scales, but recent years have seen much controversy over satellite-derived vegetation states in Amazônia, with studies predicting opposite feedbacks depending on data processing technique and interpretation. Recent results suggest that some of this uncertainty could stem from a lack of quality in atmospheric correction and cloud screening. In this paper, we assess these uncertainties by comparing the current standard surface reflectance products (MYD09, MYD09GA) and derived composites (MYD09A1, MCD43A4 and MYD13A2 - Vegetation Index) from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite to results obtained from the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm. MAIAC uses a new cloud screening technique, and novel aerosol retrieval and atmospheric correction procedures which are based on time-series and spatial analyses. Our results show considerable improvements of MAIAC processed surface reflectance compared to MYD09/MYD13 with noise levels reduced by a factor of up to 10. Uncertainties in the current MODIS surface reflectance product were mainly due to residual cloud and aerosol contamination which affected the Normalized Difference Vegetation Index (NDVI): During the wet season, with cloud cover ranging between 90 percent and 99 percent, conventionally processed NDVI was significantly depressed due to undetected clouds. A smaller reduction in NDVI due to increased

Effects of image distortion correction on voxel-based morphometry

International Nuclear Information System (INIS)

Goto, Masami; Abe, Osamu; Kabasawa, Hiroyuki

2012-01-01

We aimed to show that correcting image distortion significantly affects brain volumetry using voxel-based morphometry (VBM) and to assess whether the processing of distortion correction reduces system dependency. We obtained contiguous sagittal T 1 -weighted images of the brain from 22 healthy participants using 1.5- and 3-tesla magnetic resonance (MR) scanners, preprocessed images using Statistical Parametric Mapping 5, and tested the relation between distortion correction and brain volume using VBM. Local brain volume significantly increased or decreased on corrected images compared with uncorrected images. In addition, the method used to correct image distortion for gradient nonlinearity produced fewer volumetric errors from MR system variation. This is the first VBM study to show more precise volumetry using VBM with corrected images. These results indicate that multi-scanner or multi-site imaging trials require correction for distortion induced by gradient nonlinearity. (author)

A temperature-dependent theory for HeII: Application to the liquid structure factor

International Nuclear Information System (INIS)

Chela-Flores, J.; Ghassib, H.B.

1981-08-01

A temperature-dependent theory is presented for HeII, which is based on both a gauge-theoretic formulation as well as a mean-field (Hartree) approach. A simple model calculation is then performed within this framework for the liquid structure factor of the system. In particular, explicit expressions are obtained for the low-momentum-transfer and low-temperature limits, which seem to conform with the available experimental data. Further, the curvature of the structure factor is predicted, under these circumstances, to be only mildly dependent on temperature. Throughout, we compare and contrast with other theoretical attempts, including Feynman's. (author)

Correction

DEFF Research Database (Denmark)

Pinkevych, Mykola; Cromer, Deborah; Tolstrup, Martin

2016-01-01

[This corrects the article DOI: 10.1371/journal.ppat.1005000.][This corrects the article DOI: 10.1371/journal.ppat.1005740.][This corrects the article DOI: 10.1371/journal.ppat.1005679.].......[This corrects the article DOI: 10.1371/journal.ppat.1005000.][This corrects the article DOI: 10.1371/journal.ppat.1005740.][This corrects the article DOI: 10.1371/journal.ppat.1005679.]....

Squark production in R-symmetric SUSY with Dirac gluinos. NLO corrections

Energy Technology Data Exchange (ETDEWEB)

Diessner, Philip [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kotlarski, Wojciech [Technische Univ. Dresden (Germany). Inst. fuer Kern- und Teilchenphysik; Warsaw Univ. (Poland). Faculty of Physics; Liebschner, Sebastian; Stoeckinger, Dominik [Technische Univ. Dresden (Germany). Inst. fuer Kern- und Teilchenphysik

2017-11-15

R-symmetry leads to a distinct realisation of SUSY with a significantly modified coloured sector featuring a Dirac gluino and a scalar colour octet (sgluon). We present the impact of R-symmetry on squark production at the 13 TeV LHC. We study the total cross sections and their NLO corrections from all strongly interacting states, their dependence on the Dirac gluino mass and sgluon mass as well as their systematics for selected benchmark points. We find that tree-level cross sections in the R-symmetric model are reduced compared to the MSSM but the NLO K-factors are generally larger in the order of ten to twenty per cent. In the course of this work we derive the required DREG → DRED transition counterterms and necessary on-shell renormalisation constants. The real corrections are treated using FKS subtraction, with results cross checked against an independent calculation employing the two cut phase space slicing method.

Squark production in R-symmetric SUSY with Dirac gluinos. NLO corrections

International Nuclear Information System (INIS)

Diessner, Philip; Kotlarski, Wojciech; Warsaw Univ.; Liebschner, Sebastian; Stoeckinger, Dominik

2017-11-01

R-symmetry leads to a distinct realisation of SUSY with a significantly modified coloured sector featuring a Dirac gluino and a scalar colour octet (sgluon). We present the impact of R-symmetry on squark production at the 13 TeV LHC. We study the total cross sections and their NLO corrections from all strongly interacting states, their dependence on the Dirac gluino mass and sgluon mass as well as their systematics for selected benchmark points. We find that tree-level cross sections in the R-symmetric model are reduced compared to the MSSM but the NLO K-factors are generally larger in the order of ten to twenty per cent. In the course of this work we derive the required DREG → DRED transition counterterms and necessary on-shell renormalisation constants. The real corrections are treated using FKS subtraction, with results cross checked against an independent calculation employing the two cut phase space slicing method.

Method of absorbance correction in a spectroscopic heating value sensor

Science.gov (United States)

Saveliev, Alexei; Jangale, Vilas Vyankatrao; Zelepouga, Sergeui; Pratapas, John

2013-09-17

A method and apparatus for absorbance correction in a spectroscopic heating value sensor in which a reference light intensity measurement is made on a non-absorbing reference fluid, a light intensity measurement is made on a sample fluid, and a measured light absorbance of the sample fluid is determined. A corrective light intensity measurement at a non-absorbing wavelength of the sample fluid is made on the sample fluid from which an absorbance correction factor is determined. The absorbance correction factor is then applied to the measured light absorbance of the sample fluid to arrive at a true or accurate absorbance for the sample fluid.

Unit root tests for cross-sectionally dependent panels : The influence of observed factors

NARCIS (Netherlands)

Becheri, I.G.; Drost, F.C.; van den Akker, R.

This paper considers a heterogeneous panel unit root model with cross-sectional dependence generated by a factor structure—the factor common to all units being an observed covariate. The model is shown to be Locally Asymptotically Mixed Normal (LAMN), with the random part of the limiting Fisher

Mitigation of voltage sag, swell and power factor correction using solid-state transformer b

Directory of Open Access Journals (Sweden)

M.R. Banaei

2014-09-01

Full Text Available This paper presents a novel topology of solid-state transformer (SST. In the design process, the AC/DC, DC/AC and AC/AC converters have been integrated to achieve higher efficiency. To obtain higher efficiency from other SST with DC-link topologies, the AC/DC and DC/AC converters have been integrated in one matrix converter. The proposed SST performs typical functions and has advantages such as power factor correction, voltage sag and swell elimination, voltage flicker reduction and protection capability in fault situations. In addition, it has other benefits such as light weight, low volume and elimination of hazardous liquid dielectrics because it uses medium frequency transformer. The operation and some performances of the proposed SST have been verified by the simulation results.

Radiative corrections in neutrino-deuterium disintegration

International Nuclear Information System (INIS)

Kurylov, A.; Ramsey-Musolf, M.J.; Vogel, P.

2002-01-01

The radiative corrections of order α for the charged- and neutral-current neutrino-deuterium disintegration for energies relevant to the SNO experiment are evaluated. Particular attention is paid to the issue of the bremsstrahlung detection threshold. It is shown that the radiative corrections to the total cross section for the charged current reaction are independent of that threshold, as they must be for consistency, and amount to a slowly decreasing function of the neutrino energy E ν , varying from about 4% at low energies to 3% at the end of the 8 B spectrum. The differential cross section corrections, on the other hand, do depend on the bremsstrahlung detection threshold. Various choices of the threshold are discussed. It is shown that for a realistic choice of the threshold and for the actual electron energy threshold of the SNO detector, the deduced 8 B ν e flux should be decreased by about 2%. The radiative corrections to the neutral-current reaction are also evaluated

Fault of the correction factor for pressure and temperature k{sub PT} in the atmospheric conditions of Dosimetric Calibration Lab. - LSCD of ININ - Mexico; Falla del factor de correcion por presion y temperatura k{sub PT} a las condiciones atmosfericas del LSCD-ININ-Mexico

Energy Technology Data Exchange (ETDEWEB)

Alvarez R, Jose T.; Jesus Cejudo, A.; La Cruz H., Daniel de; Tovar M, Victor M., E-mail: trinidad.alvarez@inin.gob.mx, E-mail: jesus.cejudo@inin.gob.mx, E-mail: daniel.delacruz@inin.gob.mx, E-mail: victor.tovar@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares (LSCD/ININ), Ocoyoacac (Mexico). Laboratorio Secundario de Calibracion Dosimetrica

2013-07-01

The realization of the operational quantities H*, Hp y/0 H'(0.07) for estimating the effective dose E, usually is done by measuring the air kerma Ka air within the field of ionizing radiation of interest and was subsequently applied appropriate conversion factors for both the quality of radiation and the operational quantity of interest. However, the SSDL in performing the Ka to environmental conditions of ININ (3000 m above sea level, P ∼ 710 hPa) with ionization chambers has found that the pressure correction factor and kPT temperature is not sufficient to correct the change in air density. Indeed, in the case of {sup 60}Co the discrepancy between the measurement of a primary standard graphite walls Ka (BEV CC01 be 131) and a side of the plastic walls (Exradin A12) is on the order of 0.4% for the case of the RX BIPM qualities to 100,135, 180 and 250 kV. It was found that for a camera model 30001 PTW (PMMA graphite wall) is needed an additional correction factor k PT ranging from 0.4% to 1.5%, correction factor calculated by MC simulation. For Sk of {sup 125}I brachytherapy sources was given an additional correction lower in 11% compared to conventional k{sub PT} value measured with a well chamber Standard Imaging HDR 1000 plus. Finally, it is in the process of studying the behavior of this additional correction factor to the case of {sup 137}Cs.

Factores psicosociales en alcohólicos dependientes Psychological and social factors in dependent alcoholic patients

Directory of Open Access Journals (Sweden)

Aurora Revilla Cervantes

2012-07-01

Full Text Available Se presentan 4 casos clínicos de pacientes alcohólicos dependientes no complicados pertenecientes al Consultorio Médico de Familia No. 5 del Policlínico Docente "Frank País García", con vistas a identificar los factores psicosociales que influían en estos. Como principales condicionantes de la conducta adictiva en el grupo estudiado se observaron: la influencia del medio, las tradiciones culturales y la participación de eventos vitales de prevalencia negativa. Además, los afectados mostraron un fuerte arraigo a la conducta alcohólica y el deseo de continuarla.Four case reports of uncomplicated dependent alcoholic patients belonging to the Family Doctor's Office No. 5 from «Frank País García Teaching Polyclinic are presented with the aim of identifying the psychological and social factors influencing on them. As main conditions of the addictive behavior in the studied group there were: the influence of the environment, the cultural traditions and the participation in vital events of negative prevalence. Also, those affected showed a strong dependence on the alcoholic behavior and the desire of continuing it.

A longitudinal study of mental health symptoms in young prisoners: exploring the influence of personal factors and the correctional climate.

Science.gov (United States)

Gonçalves, Leonel C; Endrass, Jérôme; Rossegger, Astrid; Dirkzwager, Anja J E

2016-04-06

Despite the high prevalence rate of mental health problems among young prisoners, little is known about the longitudinal course and covariates of their mental health symptoms during incarceration, especially the influence of the correctional climate. The current study aimed: (1) to examine changes in young prisoners' mental health symptoms during incarceration, (2) to identify personal factors associated with their mental health symptoms and perceptions of the correctional climate, and (3) to test the incremental effect of perceptions of the correctional climate on mental health symptoms. Data were obtained from a sample of 75 youths (aged 17 to 22 years) detained in a Portuguese young offender prison. Data were gathered 1, 3, and 6 months after their admission in this facility. Socio-demographic, clinical and criminological variables were collected. Mental health symptoms and perceptions of the correctional climate were assessed through self-report assessment tools. Linear and logistic (multi-level) regressions and tests for differences between means were performed to analyze the data. Overall, mental health symptoms marginally declined by the sixth month in prison. Prisoners with a history of mental health treatment were more likely to have increased symptoms. Higher levels of mental health symptoms were associated with a history of mental health treatment, remand status, and a lower educational level. Better perceptions of the correctional climate were associated with Black race and participation in prison activities. A negative perception of the correctional climate was the strongest covariate of young prisoners' mental health symptoms and had incremental validity over that of personal variables. The results highlight that both characteristics of the prisoners and of the prison environment influence young prisoners' mental health. Prison management can try to reduce young prisoners' mental health problems by developing scientific procedures for their mental

A Humidity-Dependent Lifetime Derating Factor for DC Film Capacitors

DEFF Research Database (Denmark)

Wang, Huai; Reigosa, Paula Diaz; Blaabjerg, Frede

2015-01-01

accelerated testing of film capacitors under different humidity conditions, enabling a more justified lifetime prediction of film capacitors for DC-link applications under specific climatic environments. The analysis of the testing results and the detailed discussion on the derating factor with different......Film capacitors are widely assumed to have superior reliability performance than Aluminum electrolytic capacitors in DC-link design of power electronic converters. However, the assumption needs to be critically judged especially for applications under high humidity environments. This paper proposes...... a humidity-dependent lifetime derating factor for a type of plastic-boxed metallized DC film capacitors. It overcomes the limitation that the humidity impact is not considered in the state-of-the-art DC film capacitor lifetime models. The lifetime derating factor is obtained based on a total of 8,700 hours...

Country-dependent characterisation factors for acidification in Europe - A critical evaluation

NARCIS (Netherlands)

Hettelingh, JP; Posch, M; Potting, J

2005-01-01

Goal, Scope and Background. Country-dependent characterisation factors for acidification have been derived for use in life cycle assessments to describe the effect on ecosystem protection of a change in national emissions. They have recently also been used in support of European air pollution

The effect of utilising age and sex dependent factors for calculating detriment from medical irradiation

International Nuclear Information System (INIS)

Mettler, F.A.; Davis, M.; Moseley, R.D.; Kelsey, C.A.

1986-01-01

Proposals have been made for a quantity that can be used to estimate possible detriment from medical radiology better than the ICRP's collective effective dose equivalent. One such approach utilises age and sex dependent 'weighting' factors. The magnitude of the effect obtained by utilising such factors when applied to an actual population has not been previously assessed. When age and sex dependent weighting factors are applied to diagnostic medical radiology for all hospital examinations conducted in the United States in 1980, estimates of detriment are reduced by one-third. (author)

Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET-MR: Phantom and patient studies