Activation Time of Cardiac Tissue In Response to a Linear Array of Spatial Alternating Bipolar Electrodes

NASA Astrophysics Data System (ADS)

Mashburn, David; Wikswo, John

2007-11-01

Prevailing theories about the response of the heart to high field shocks predict that local regions of high resistivity distributed throughout the heart create multiple small virtual electrodes that hyperpolarize or depolarize tissue and lead to widespread activation. This resetting of bulk tissue is responsible for the successful functioning of cardiac defibrillators. By activating cardiac tissue with regular linear arrays of spatially alternating bipolar currents, we can simulate these potentials locally. We have studied the activation time due to distributed currents in both a 1D Beeler-Reuter model and on the surface of the whole heart, varying the strength of each source and the separation between them. By comparison with activation time data from actual field shock of a whole heart in a bath, we hope to better understand these transient virtual electrodes. Our work was done on rabbit RV using florescent optical imaging and our Phased Array Stimulator for driving the 16 current sources. Our model shows that for a total absolute current delivered to a region of tissue, the entire region activates faster if above-threshold sources are more distributed.

Normalization of a collimated 14.7 MeV neutron source in a neutron spectrometry system for benchmark experiments

NASA Astrophysics Data System (ADS)

Ofek, R.; Tsechanski, A.; Shani, G.

1988-05-01

In the present study a method used to normalize a collimated 14.7 MeV neutron beam is introduced. It combined a measurement of the fast neutron scalar flux passing through the collimator, using a copper foil activation, with a neutron transport calculation of the foil activation per unit source neutron, carried out by the discrete-ordinates transport code DOT 4.2. The geometry of the collimated neutron beam is composed of a D-T neutron source positioned 30 cm in front of a 6 cm diameter collimator, through a 120 cm thick paraffin wall. The neutron flux emitted from the D-T source was counted by an NE-213 scintillator, simultaneously with the irradiation of the copper foil. Thus, the determination of the normalization factor of the D-T source is used for an absolute flux calibration of the NE-213 scintillator. The major contributions to the uncertainty in the determination of the normalization factor, and their origins, are discussed.

Absolute measurement of (198)Au activity in gold foil using plastic scintillators and a well-type NaI(Tl) detector.

PubMed

Kim, Yun Ho; Kim, Jungho; Lee, Jong-Man; Park, Hyeonseo

2016-03-01

A beta-gamma coincidence system has been developed for measuring (198)Au activity in gold foils. The system was validated by Monte Carlo simulations and by measuring the activity of a (60)Co point-source. To study effects such as self-shielding of beta particles in gold foils, (198)Au activity measurements and simulations were performed for various scintillators and foil sizes. The measured (198)Au activities were ~1% above the reference activity, which might be due to self-shielding of beta particles. The measured and simulated (198)Au activities agreed, suggesting feasibility of precise activity measurement. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of Two Methodologies for Calibrating Satellite Instruments in the Visible and Near-Infrared

NASA Technical Reports Server (NTRS)

Barnes, Robert A.; Brown, Steven W.; Lykke, Keith R.; Guenther, Bruce; Butler, James J.; Schwarting, Thomas; Turpie, Kevin; Moyer, David; DeLuccia, Frank; Moeller, Christopher

2015-01-01

Traditionally, satellite instruments that measure Earth-reflected solar radiation in the visible and near infrared wavelength regions have been calibrated for radiance responsivity in a two-step method. In the first step, the relative spectral response (RSR) of the instrument is determined using a nearly monochromatic light source such as a lamp-illuminated monochromator. These sources do not typically fill the field-of-view of the instrument nor act as calibrated sources of light. Consequently, they only provide a relative (not absolute) spectral response for the instrument. In the second step, the instrument views a calibrated source of broadband light, such as a lamp-illuminated integrating sphere. The RSR and the sphere absolute spectral radiance are combined to determine the absolute spectral radiance responsivity (ASR) of the instrument. More recently, a full-aperture absolute calibration approach using widely tunable monochromatic lasers has been developed. Using these sources, the ASR of an instrument can be determined in a single step on a wavelength-by-wavelength basis. From these monochromatic ASRs, the responses of the instrument bands to broadband radiance sources can be calculated directly, eliminating the need for calibrated broadband light sources such as lamp-illuminated integrating spheres. In this work, the traditional broadband source-based calibration of the Suomi National Preparatory Project (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) sensor is compared with the laser-based calibration of the sensor. Finally, the impact of the new full-aperture laser-based calibration approach on the on-orbit performance of the sensor is considered.

Comparison of two methodologies for calibrating satellite instruments in the visible and near infrared

PubMed Central

Barnes, Robert A.; Brown, Steven W.; Lykke, Keith R.; Guenther, Bruce; Butler, James J.; Schwarting, Thomas; Moyer, David; Turpie, Kevin; DeLuccia, Frank; Moeller, Christopher

2016-01-01

Traditionally, satellite instruments that measure Earth-reflected solar radiation in the visible and near infrared wavelength regions have been calibrated for radiance responsivity in a two-step method. In the first step, the relative spectral response (RSR) of the instrument is determined using a nearly monochromatic light source such as a lamp-illuminated monochromator. These sources do not typically fill the field-of-view of the instrument nor act as calibrated sources of light. Consequently, they only provide a relative (not absolute) spectral response for the instrument. In the second step, the instrument views a calibrated source of broadband light, such as a lamp-illuminated integrating sphere. The RSR and the sphere absolute spectral radiance are combined to determine the absolute spectral radiance responsivity (ASR) of the instrument. More recently, a full-aperture absolute calibration approach using widely tunable monochromatic lasers has been developed. Using these sources, the ASR of an instrument can be determined in a single step on a wavelength-by-wavelength basis. From these monochromatic ASRs, the responses of the instrument bands to broadband radiance sources can be calculated directly, eliminating the need for calibrated broadband light sources such as integrating spheres. In this work, the traditional broadband source-based calibration of the Suomi National Preparatory Project (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) sensor is compared with the laser-based calibration of the sensor. Finally, the impact of the new full-aperture laser-based calibration approach on the on-orbit performance of the sensor is considered. PMID:26836861

A multicentre audit of HDR/PDR brachytherapy absolute dosimetry in association with the INTERLACE trial (NCT015662405).

PubMed

Díez, P; Aird, E G A; Sander, T; Gouldstone, C A; Sharpe, P H G; Lee, C D; Lowe, G; Thomas, R A S; Simnor, T; Bownes, P; Bidmead, M; Gandon, L; Eaton, D; Palmer, A L

2017-11-09

A UK multicentre audit to evaluate HDR and PDR brachytherapy has been performed using alanine absolute dosimetry. This is the first national UK audit performing an absolute dose measurement at a clinically relevant distance (20 mm) from the source. It was performed in both INTERLACE (a phase III multicentre trial in cervical cancer) and non-INTERLACE brachytherapy centres treating gynaecological tumours. Forty-seven UK centres (including the National Physical Laboratory) were visited. A simulated line source was generated within each centre's treatment planning system and dwell times calculated to deliver 10 Gy at 20 mm from the midpoint of the central dwell (representative of Point A of the Manchester system). The line source was delivered in a water-equivalent plastic phantom (Barts Solid Water) encased in blocks of PMMA (polymethyl methacrylate) and charge measured with an ion chamber at 3 positions (120° apart, 20 mm from the source). Absorbed dose was then measured with alanine at the same positions and averaged to reduce source positional uncertainties. Charge was also measured at 50 mm from the source (representative of Point B of the Manchester system). Source types included 46 HDR and PDR 192 Ir sources, (7 Flexisource, 24 mHDR-v2, 12 GammaMed HDR Plus, 2 GammaMed PDR Plus, 1 VS2000) and 1 HDR 60 Co source, (Co0.A86). Alanine measurements when compared to the centres' calculated dose showed a mean difference (±SD) of  +1.1% (±1.4%) at 20 mm. Differences were also observed between source types and dose calculation algorithm. Ion chamber measurements demonstrated significant discrepancies between the three holes mainly due to positional variation of the source within the catheter (0.4%-4.9% maximum difference between two holes). This comprehensive audit of absolute dose to water from a simulated line source showed all centres could deliver the prescribed dose to within 5% maximum difference between measurement and calculation.

First Absolutely Calibrated Localized Measurements of Ion Velocity in the MST in Locked and Rotating Plasmas

NASA Astrophysics Data System (ADS)

Baltzer, M.; Craig, D.; den Hartog, D. J.; Nornberg, M. D.; Munaretto, S.

2015-11-01

An Ion Doppler Spectrometer (IDS) is used on MST for high time-resolution passive and active measurements of impurity ion emission. Absolutely calibrated measurements of flow are difficult because the spectrometer records data within 0.3 nm of the C+5 line of interest, and commercial calibration lamps do not produce lines in this narrow range . A novel optical system was designed to absolutely calibrate the IDS. The device uses an UV LED to produce a broad emission curve in the desired region. A Fabry-Perot etalon filters this light, cutting transmittance peaks into the pattern of the LED emission. An optical train of fused silica lenses focuses the light into the IDS with f/4. A holographic diffuser blurs the light cone to increase homogeneity. Using this light source, the absolute Doppler shift of ion emissions can be measured in MST plasmas. In combination with charge exchange recombination spectroscopy, localized ion velocities can now be measured. Previously, a time-averaged measurement along the chord bisecting the poloidal plane was used to calibrate the IDS; the quality of these central chord calibrations can be characterized with our absolute calibration. Calibration errors may also be quantified and minimized by optimizing the curve-fitting process. Preliminary measurements of toroidal velocity in locked and rotating plasmas will be shown. This work has been supported by the US DOE.

Regulation of phosphoenolpyruvate carboxykinase and pyruvate kinase in Saccharomyces cerevisiae grown in the presence of glycolytic and gluconeogenic carbon sources and the role of mitochondrial function on gluconeogenesis.

PubMed

Wilson, A J; Bhattacharjee, J K

1986-12-01

Phosphoenolpyruvate carboxykinase (PEPCKase) and pyruvate kinase (PKase) were measured in Saccharomyces cerevisiae grown in the presence of glycolytic and gluconeogenic carbon sources. The PEPCKase activity was highest in ethanol-grown cells. However, high PEPCKase activity was also observed in cells grown in 1% glucose, especially as compared with the activity of sucrose-, maltose-, or galactose-grown cells. Activity was first detected after 12 h when glucose was exhausted from the growth medium. The PKase activity was very high in glucose-grown cells; considerable activity was also present in ethanol- and pyruvate-grown cells. The absolute requirement of respiration for gluconeogenesis was demonstrated by the absence or significantly low levels of PEPCKase and fructose-1,6-bisphosphatase activities observed in respiratory deficient mutants, as well as in wild-type S. cerevisiae cells grown in the presence of glucose and antimycin A or chloramphenicol. Obligate glycolytic and gluconeogenic enzymes were present simultaneously only in stationary phase cells, but not in exponential phase cells; hence futile cycling could not occur in log phase cells regardless of the presence of carbon source in the growth medium.

On Day-to-Day Variability of Global Lightning Activity as Quantified from Background Schumann Resonance Observations

NASA Astrophysics Data System (ADS)

Mushtak, V. C.; Williams, E. R.

2011-12-01

Among the palette of methods (satellite, VLF, ELF) for monitoring global lightning activity, observations of the background Schumann resonances (SR) provide a unique prospect for estimating the integrated activity of global lightning activity in absolute units (coul2 km2/sec). This prospect is ensured by the SR waves' low attenuation, with wavelengths commensurate with the dimensions of dominant regional lightning "chimneys", and by the accumulating methodology for background SR techniques. Another benefit is the reduction of SR measurements into a compact set of resonance characteristics (modal frequencies, intensities, and quality factors). Suggested and tested in numerical simulations by T.R. Madden in the 1960s, the idea to invert the SR characteristics for the global lightning source has been farther developed, statistically substantiated, and practically realized here on the basis of the computing power and the quantity of experimental material way beyond what the SR pioneers had at their disposal. The critical issue of the quality of the input SR parameters is addressed by implementing a statistically substantiated sanitizing procedure to dispose of the fragments of the observed time series containing unrepresentative elements - local interference of various origin and strong ELF transients originating outside the major "chimneys" represented in the source model. As a result of preliminary research, a universal empirical sanitizing criterion has been established. Due to the fact that the actual observations have been collected from a set of individually organized ELF stations with various equipment sets and calibration techniques, the relative parameters in both input (the intensities) and output (the "chimney" activities) are being used as far as possible in the inversion process to avoid instabilities caused by calibration inconsistencies. The absolute regional activities - and so the sought for global activity in absolute units - is determined in the final stage from the estimated positions and relative activities of the modeled "chimneys" using SR power spectra at the stations with the most reliable calibrations. Additional stabilization in the procedure has been achieved by exploiting the Le Come/Goltzman inversion algorithm that uses the empirically estimated statistical characteristics of the input parameters. When applied to electric and/or magnetic observations collected simultaneously in January 2009 from six ELF stations in Poland (Belsk), Japan (Moshiri), Hungary (Nagycenk), USA (Rhode Island), India (Shillong), and Antarctica (Syowa), the inversion procedure reveals a general repeatability of diurnal lightning scenarios with variations of "chimney" centroid locations by a few megameters, while the estimated regional activity has been found to vary from day to day by up to several tens of percent. A combined empirical-theoretical analysis of the collected data aimed at selecting the most reliably calibrated ELF stations is presently in progress. All the effort is being made to transform the relative lightning activity into absolute units by the time of this meeting. The authors are greatly thankful to all the experimentalists who generously provided their observations and related information for this study.

Fundamental principles of absolute radiometry and the philosophy of this NBS program (1968 to 1971)

NASA Technical Reports Server (NTRS)

Geist, J.

1972-01-01

A description is given work performed on a program to develop an electrically calibrated detector (also called absolute radiometer, absolute detector, and electrically calibrated radiometer) that could be used to realize, maintain, and transfer a scale of total irradiance. The program includes a comprehensive investigation of the theoretical basis of absolute detector radiometry, as well as the design and construction of a number of detectors. A theoretical analysis of the sources of error is also included.

A fast signal subspace approach for the determination of absolute levels from phased microphone array measurements

NASA Astrophysics Data System (ADS)

Sarradj, Ennes

2010-04-01

Phased microphone arrays are used in a variety of applications for the estimation of acoustic source location and spectra. The popular conventional delay-and-sum beamforming methods used with such arrays suffer from inaccurate estimations of absolute source levels and in some cases also from low resolution. Deconvolution approaches such as DAMAS have better performance, but require high computational effort. A fast beamforming method is proposed that can be used in conjunction with a phased microphone array in applications with focus on the correct quantitative estimation of acoustic source spectra. This method bases on an eigenvalue decomposition of the cross spectral matrix of microphone signals and uses the eigenvalues from the signal subspace to estimate absolute source levels. The theoretical basis of the method is discussed together with an assessment of the quality of the estimation. Experimental tests using a loudspeaker setup and an airfoil trailing edge noise setup in an aeroacoustic wind tunnel show that the proposed method is robust and leads to reliable quantitative results.

Absolute calibration of a hydrogen discharge lamp in the vacuum ultraviolet

NASA Technical Reports Server (NTRS)

Nealy, J. E.

1975-01-01

A low-pressure hydrogen discharge lamp was calibrated for radiant intensity in the vacuum ultraviolet spectral region on an absolute basis and was employed as a laboratory standard source in spectrograph calibrations. This calibration was accomplished through the use of a standard photodiode detector obtained from the National Bureau of Standards together with onsite measurements of spectral properties of optical components used. The stability of the light source for use in the calibration of vacuum ultraviolet spectrographs and optical systems was investigated and found to be amenable to laboratory applications. The lamp was studied for a range of operating parameters; the results indicate that with appropriate peripheral instrumentation, the light source can be used as a secondary laboratory standard source when operated under preset controlled conditions. Absolute intensity measurements were recorded for the wavelengths 127.7, 158.0, 177.5, and 195.0 nm for a time period of over 1 month, and the measurements were found to be repeatable to within 11 percent.

Mosquito larvicidal activity of Rauvolfia serpentina L. seeds against Culex quinquefasciatus Say.

PubMed

Das, Dipanwita; Chandra, Goutam

2012-01-01

To establish the larvicidal activities, if any of solvent extracts of Rauvolfia serpentina (R. serpentina) L. seeds against Culex quinquefasciatus (Cx. quinquefasciatus) Say, 1823 as target species. Seeds of R. serpentina were extracted with five solvents graded according to the polarity [viz. petroleum ether, benzene, ethyl acetate, acetone and absolute alcohol] continuing one after another with the same seeds. Mortality rate with petroleum ether extract was significantly higher than other extracts. The mortality rates of late 3rd instar larvae were 50.33±5.51, 10.00±1.00, 0.00±0.00, 21.33±1.53 and 0.00±0.00 in 100 ppm concentration of petroleum ether, benzene, ethyl acetate, acetone and absolute alcohol respectively, after 24 h of exposure period. Results of this study show that petroleum ether extract of R. serpentina seed may be considered as a potent source of mosquito larvicidal agent. Copyright © 2012 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

The Herschel Multi-Tiered Extragalactic Survey: SPIRE-mm Photometric Redshifts

NASA Technical Reports Server (NTRS)

Roseboom, I. G.; Ivison, R. J.; Greve, T. R.; Amblard, A.; Arumugam, V.; Auld, R.; Aussel, H.; Bethermin, M.; Blain, A.; Block, J.;

Accuracy of Monte Carlo photon transport simulation in characterizing brachytherapy dosimeter energy-response artefacts

NASA Astrophysics Data System (ADS)

Das, R. K.; Li, Z.; Perera, H.; Williamson, J. F.

1996-06-01

Practical dosimeters in brachytherapy, such as thermoluminescent dosimeters (TLD) and diodes, are usually calibrated against low-energy megavoltage beams. To measure absolute dose rate near a brachytherapy source, it is necessary to establish the energy response of the detector relative to that of the calibration energy. The purpose of this paper is to assess the accuracy of Monte Carlo photon transport (MCPT) simulation in modelling the absolute detector response as a function of detector geometry and photon energy. We have exposed two different sizes of TLD-100 (LiF chips) and p-type silicon diode detectors to calibrated , HDR source and superficial x-ray beams. For the Scanditronix electron-field diode, the relative detector response, defined as the measured detector readings per measured unit of air kerma, varied from (40 kVp beam) to ( beam). Similarly for the large and small chips the same quantity varied from and , respectively. Monte Carlo simulation was used to calculate the absorbed dose to the active volume of the detector per unit air kerma. If the Monte Carlo simulation is accurate, then the absolute detector response, which is defined as the measured detector reading per unit dose absorbed by the active detector volume, and is calculated by Monte Carlo simulation, should be a constant. For the diode, the absolute response is . For TLDs of size the absolute response is and for TLDs of it is . From the above results we can conclude that the absolute response function of detectors (TLDs and diodes) is directly proportional to absorbed dose by the active volume of the detector and is independent of beam quality.

Source apportionment of soil heavy metals using robust absolute principal component scores-robust geographically weighted regression (RAPCS-RGWR) receptor model.

PubMed

Qu, Mingkai; Wang, Yan; Huang, Biao; Zhao, Yongcun

2018-06-01

The traditional source apportionment models, such as absolute principal component scores-multiple linear regression (APCS-MLR), are usually susceptible to outliers, which may be widely present in the regional geochemical dataset. Furthermore, the models are merely built on variable space instead of geographical space and thus cannot effectively capture the local spatial characteristics of each source contributions. To overcome the limitations, a new receptor model, robust absolute principal component scores-robust geographically weighted regression (RAPCS-RGWR), was proposed based on the traditional APCS-MLR model. Then, the new method was applied to the source apportionment of soil metal elements in a region of Wuhan City, China as a case study. Evaluations revealed that: (i) RAPCS-RGWR model had better performance than APCS-MLR model in the identification of the major sources of soil metal elements, and (ii) source contributions estimated by RAPCS-RGWR model were more close to the true soil metal concentrations than that estimated by APCS-MLR model. It is shown that the proposed RAPCS-RGWR model is a more effective source apportionment method than APCS-MLR (i.e., non-robust and global model) in dealing with the regional geochemical dataset. Copyright © 2018 Elsevier B.V. All rights reserved.

Active wavefront control challenges of the NASA Large Deployable Reflector (LDR)

NASA Technical Reports Server (NTRS)

Meinel, Aden B.; Meinel, Marjorie P.; Manhart, Paul K.; Hochberg, Eric B.

1989-01-01

The 20-m Large Deployable Reflector will have a segmented primary mirror. Achieving diffraction-limited performance at 50 microns requires correction for the errors of tilt and piston of the primary mirror. This correction can be obtained in two ways, the use of an active primary or a correction at a demagnified pupil of the primary. A critical requirement is the means for measurement of the wavefront error and maintaining phasing during the observation of objects that may be too faint for determining the error. Absolute phasing can only be determined using a cooperative source. Maintenance of phasing can be done with an on-board source. A number of options are being explored as discussed below. The many issues concerning the assessment and control of an active segmented mirror will be addressed with an early construction of the Precision Segmented Reflector testbed.

Active wavefront control challenges of the NASA Large Deployable Reflector (LDR)

NASA Astrophysics Data System (ADS)

Meinel, Aden B.; Meinel, Marjorie P.; Manhart, Paul K.; Hochberg, Eric B.

1989-09-01

The 20-m Large Deployable Reflector will have a segmented primary mirror. Achieving diffraction-limited performance at 50 microns requires correction for the errors of tilt and piston of the primary mirror. This correction can be obtained in two ways, the use of an active primary or a correction at a demagnified pupil of the primary. A critical requirement is the means for measurement of the wavefront error and maintaining phasing during the observation of objects that may be too faint for determining the error. Absolute phasing can only be determined using a cooperative source. Maintenance of phasing can be done with an on-board source. A number of options are being explored as discussed below. The many issues concerning the assessment and control of an active segmented mirror will be addressed with an early construction of the Precision Segmented Reflector testbed.

Predicting the sensitivity of the beryllium/scintillator layer neutron detector using Monte Carlo and experimental response functions.

PubMed

Styron, J D; Cooper, G W; Ruiz, C L; Hahn, K D; Chandler, G A; Nelson, A J; Torres, J A; McWatters, B R; Carpenter, Ken; Bonura, M A

2014-11-01

A methodology for obtaining empirical curves relating absolute measured scintillation light output to beta energy deposited is presented. Output signals were measured from thin plastic scintillator using NIST traceable beta and gamma sources and MCNP5 was used to model the energy deposition from each source. Combining the experimental and calculated results gives the desired empirical relationships. To validate, the sensitivity of a beryllium/scintillator-layer neutron activation detector was predicted and then exposed to a known neutron fluence from a Deuterium-Deuterium fusion plasma (DD). The predicted and the measured sensitivity were in statistical agreement.

Activities of NIST (National Inst. of Standards and Technology)

NASA Technical Reports Server (NTRS)

1992-01-01

The Radiometric Physics Division of the NIST is responsible for the national standards in radiation thermometry, spectroradiometry, photometry, and spectrophotometry; dissemination of these standards by providing measurement services to customers requiring calibrations of the highest accuracy; and conducting fundamental and applied research to develop the scientific basis for future measurement services. Its relevance to EOS/TIR calibration includes calibrating unknown blackbody for radiance using a well-characterized NIST blackbody source by matching the radiant fluxes with an IR radiometer. The TIR Round Robin is used to verify the calibration of the sources that are used for the absolute radiometric calibration of the individual EOS sensors.

Behaviors of Absolute Densities of N, H, and NH3 at Remote Region of High-Density Radical Source Employing N2-H2 Mixture Plasmas

NASA Astrophysics Data System (ADS)

Chen, Shang; Kondo, Hiroki; Ishikawa, Kenji; Takeda, Keigo; Sekine, Makoto; Kano, Hiroyuki; Den, Shoji; Hori, Masaru

2011-01-01

For an innovation of molecular-beam-epitaxial (MBE) growth of gallium nitride (GaN), the measurements of absolute densities of N, H, and NH3 at the remote region of the radical source excited by plasmas have become absolutely imperative. By vacuum ultraviolet absorption spectroscopy (VUVAS) at a relatively low pressure of about 1 Pa, we obtained a N atom density of 9×1012 cm-3 for a pure nitrogen gas used, a H atom density of 7×1012 cm-3 for a gas composition of 80% hydrogen mixed with nitrogen gas were measured. The maximum density 2×1013 cm-3 of NH3 was measured by quadruple mass spectrometry (QMS) at H2/(N2+H2)=60%. Moreover, we found that N atom density was considerably affected by processing history, where the characteristic instability was observed during the pure nitrogen plasma discharge sequentially after the hydrogen-containing plasma discharge. These results indicate imply the importance of establishing radical-based processes to control precisely the absolute densities of N, H, and NH3 at the remote region of the radical source.

P and S wave Coda Calibration in Central Asia and South Korea

NASA Astrophysics Data System (ADS)

Kim, D.; Mayeda, K.; Gok, R.; Barno, J.; Roman-Nieves, J. I.

2017-12-01

Empirically derived coda source spectra provide unbiased, absolute moment magnitude (Mw) estimates for events that are normally too small for accurate long-period waveform modeling. In this study, we obtain coda-derived source spectra using data from Central Asia (Kyrgyzstan networks - KN and KR, and Tajikistan - TJ) and South Korea (Korea Meteorological Administration, KMA). We used a recently developed coda calibration module of Seismic WaveForm Tool (SWFT). Seismic activities during this recording period include the recent Gyeongju earthquake of Mw=5.3 and its aftershocks, two nuclear explosions from 2009 and 2013 in North Korea, and a small number of construction and mining-related explosions. For calibration, we calculated synthetic coda envelopes for both P and S waves based on a simple analytic expression that fits the observed narrowband filtered envelopes using the method outlined in Mayeda et al. (2003). To provide an absolute scale of the resulting source spectra, path and site corrections are applied using independent spectral constraints (e.g., Mw and stress drop) from three Kyrgyzstan events and the largest events of the Gyeongju sequence in Central Asia and South Korea, respectively. In spite of major tectonic differences, stable source spectra were obtained in both regions. We validated the resulting spectra by comparing the ratio of raw envelopes and source spectra from calibrated envelopes. Spectral shapes of earthquakes and explosions show different patterns in both regions. We also find (1) the source spectra derived from S-coda is more robust than that from the P-coda at low frequencies; (2) unlike earthquake events, the source spectra of explosions have a large disagreement between P and S waves; and (3) similarity is observed between 2016 Gyeongju and 2011 Virginia earthquake sequence in the eastern U.S.

A multicentre audit of HDR/PDR brachytherapy absolute dosimetry in association with the INTERLACE trial (NCT015662405)

NASA Astrophysics Data System (ADS)

Díez, P.; Aird, E. G. A.; Sander, T.; Gouldstone, C. A.; Sharpe, P. H. G.; Lee, C. D.; Lowe, G.; Thomas, R. A. S.; Simnor, T.; Bownes, P.; Bidmead, M.; Gandon, L.; Eaton, D.; Palmer, A. L.

2017-12-01

A UK multicentre audit to evaluate HDR and PDR brachytherapy has been performed using alanine absolute dosimetry. This is the first national UK audit performing an absolute dose measurement at a clinically relevant distance (20 mm) from the source. It was performed in both INTERLACE (a phase III multicentre trial in cervical cancer) and non-INTERLACE brachytherapy centres treating gynaecological tumours. Forty-seven UK centres (including the National Physical Laboratory) were visited. A simulated line source was generated within each centre’s treatment planning system and dwell times calculated to deliver 10 Gy at 20 mm from the midpoint of the central dwell (representative of Point A of the Manchester system). The line source was delivered in a water-equivalent plastic phantom (Barts Solid Water) encased in blocks of PMMA (polymethyl methacrylate) and charge measured with an ion chamber at 3 positions (120° apart, 20 mm from the source). Absorbed dose was then measured with alanine at the same positions and averaged to reduce source positional uncertainties. Charge was also measured at 50 mm from the source (representative of Point B of the Manchester system). Source types included 46 HDR and PDR 192Ir sources, (7 Flexisource, 24 mHDR-v2, 12 GammaMed HDR Plus, 2 GammaMed PDR Plus, 1 VS2000) and 1 HDR 60Co source, (Co0.A86). Alanine measurements when compared to the centres’ calculated dose showed a mean difference (±SD) of  +1.1% (±1.4%) at 20 mm. Differences were also observed between source types and dose calculation algorithm. Ion chamber measurements demonstrated significant discrepancies between the three holes mainly due to positional variation of the source within the catheter (0.4%-4.9% maximum difference between two holes). This comprehensive audit of absolute dose to water from a simulated line source showed all centres could deliver the prescribed dose to within 5% maximum difference between measurement and calculation.

The Galex Time Domain Survey. I. Selection And Classification of Over a Thousand Ultraviolet Variable Sources

NASA Technical Reports Server (NTRS)

Gezari, S.; Martin, D. C.; Forster, K.; Neill, J. D.; Huber, M.; Heckman, T.; Bianchi, L.; Morrissey, P.; Neff, S. G.; Seibert, M.;

A Grazing Incidence Spectrograph as Applied to Vacuum Ultraviolet, Soft X-Ray, Pulsed Plasma Sources.

DTIC Science & Technology

A 2.2-meter variable angle of incidence grazing incidence spectrograph is described for photographic recording of spectra down to 10A. Also a method for determining the absolute total fluence from a pulsed plasma source, knowing the absolute sensitivity of the instrument, is described. Spectra are presented from a low-inductance sliding spark gap and a 20-kj dense plasma focus . A program for spectram analysis is included. (Modified author abstract)

A tritium activity monitor for the KATRIN Experiment

NASA Astrophysics Data System (ADS)

Schmitt, Udo

2008-06-01

The KArlsruhe TRItium Neutrino experiment KATRIN is designed to measure the absolute neutrino mass scale by analyzing the endpoint region of the tritium beta-decay spectrum with a sensitivity of 0.2 eV/c2 (90 % C.L.). A high-luminous windowless gaseous tritium source with an activity of 1.7 · 1011 Bq will produce the decay electrons, their energy spectrum will be analyzed by a combination of two electrostatic retarding spectrometers with magnetic adiabatic collimation (MAC-E-filter). Fluctuations of the source column density and inelastic scattering processes within the source affect the energy distribution of the decay electrons. Hence, a precise and continuous monitoring of the source activity is necessary to correct the data taken by the main detector. A prototype of the beam monitor detector, based on a silicon drift diode, has been developed to measure an expected counting rate in the range of 106/(s · mm2). The detector element shall be moveable across the complete beam in a magnetic field of 0.8 T, resulting in a beam diameter of 20 cm. A precise sensor positioning device has been designed and built to be compatible with the primary beamline vacuum of 10-11 mbar.

Microwave Brightness Temperature and Its Relation to Atmospheric General Circulation Features

DTIC Science & Technology

1989-05-17

absolute temperature. Molecules may absorb electromagnetic radiation and transition to a higher energy level, or emit radiation and transition to a lower...Walker, 1970). In the microwave region, thermal emission is the only 10 source of radiation and is dependent on the absolute temperature of the...substance as determined by the Planck function. The relationship between absolute temperature and radiation emitted is given by Planck’s Law for a

Quadratic Optimization in the Problems of Active Control of Sound

NASA Technical Reports Server (NTRS)

Loncaric, J.; Tsynkov, S. V.; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

We analyze the problem of suppressing the unwanted component of a time-harmonic acoustic field (noise) on a predetermined region of interest. The suppression is rendered by active means, i.e., by introducing the additional acoustic sources called controls that generate the appropriate anti-sound. Previously, we have obtained general solutions for active controls in both continuous and discrete formulations of the problem. We have also obtained optimal solutions that minimize the overall absolute acoustic source strength of active control sources. These optimal solutions happen to be particular layers of monopoles on the perimeter of the protected region. Mathematically, minimization of acoustic source strength is equivalent to minimization in the sense of L(sub 1). By contrast. in the current paper we formulate and study optimization problems that involve quadratic functions of merit. Specifically, we minimize the L(sub 2) norm of the control sources, and we consider both the unconstrained and constrained minimization. The unconstrained L(sub 2) minimization is certainly the easiest problem to address numerically. On the other hand, the constrained approach allows one to analyze sophisticated geometries. In a special case, we call compare our finite-difference optimal solutions to the continuous optimal solutions obtained previously using a semi-analytic technique. We also show that the optima obtained in the sense of L(sub 2) differ drastically from those obtained in the sense of L(sub 1).

Decomposing health inequality with population-based surveys: a case study in Rwanda.

PubMed

Liu, Kai; Lu, Chunling

2018-05-10

Ensuring equal access to care and providing financial risk protection are at the center of the global health agenda. While Rwanda has made impressive progress in improving health outcomes, inequalities in medical care utilization and household catastrophic health spending (HCHS) between the impoverished and non-impoverished populations persist. Decomposing inequalities will help us understand the factors contributing to inequalities and design effective policy instruments in reducing inequalities. This study aims to decompose the inequalities in medical care utilization among those reporting illnesses and HCHS between the poverty and non-poverty groups in Rwanda. Using the 2005 and 2010 nationally representative Integrated Living Conditions Surveys, our analysis focuses on measuring contributions to inequalities from poverty status and other sources. We conducted multivariate logistic regression analysis to obtain poverty's contribution to inequalities by controlling for all observed covariates. We used multivariate nonlinear decomposition method with logistic regression models to partition the relative and absolute contributions from other sources to inequalities due to compositional or response effects. Poverty status accounted for the majority of inequalities in medical care utilization (absolute contribution 0.093 in 2005 and 0.093 in 2010) and HCHS (absolute contribution 0.070 in 2005 and 0.032 in 2010). Health insurance status (absolute contribution 0.0076 in 2005 and 0.0246 in 2010) and travel time to health centers (absolute contribution 0.0025 in 2005 and 0.0014 in 2010) were significant contributors to inequality in medical care utilization. Health insurance status (absolute contribution 0.0021 in 2005 and 0.0011 in 2010), having under-five children (absolute contribution 0.0012 in 2005 and 0.0011 in 2010), and having disabled family members (absolute contribution 0.0002 in 2005 and 0.0001 in 2010) were significant contributors to inequality in HCHS. Between 2005 and 2010, the main sources of the inequalities remained unchanged. Expanding insurance coverage and reducing travel time to health facilities for those living in poverty could be used as policy instruments to mitigate inequalities in medical care utilization and HCHS between the poverty and non-poverty groups.

Comparison of Two Methodologies for Calibrating Satellite Instruments in the Visible and Near Infrared

NASA Technical Reports Server (NTRS)

Barnes, Robert A.; Brown, Steven W.; Lykke, Keith R.; Guenther, Bruce; Xiong, Xiaoxiong (Jack); Butler, James J.

2010-01-01

Traditionally, satellite instruments that measure Earth-reflected solar radiation in the visible and near infrared wavelength regions have been calibrated for radiance response in a two-step method. In the first step, the spectral response of the instrument is determined using a nearly monochromatic light source, such a lamp-illuminated monochromator. Such sources only provide a relative spectral response (RSR) for the instrument, since they do not act as calibrated sources of light nor do they typically fill the field-of-view of the instrument. In the second step, the instrument views a calibrated source of broadband light, such as lamp-illuminated integrating sphere. In the traditional method, the RSR and the sphere spectral radiance are combined and, with the instrument's response, determine the absolute spectral radiance responsivity of the instrument. More recently, an absolute calibration system using widely tunable monochromatic laser systems has been developed, Using these sources, the absolute spectral responsivity (ASR) of an instrument can be determined on a wavelength-hy-wavelength basis. From these monochromatic ASRs. the responses of the instrument bands to broadband radiance sources can be calculated directly, eliminating the need for calibrated broadband light sources such as integrating spheres. Here we describe the laser-based calibration and the traditional broad-band source-based calibration of the NPP VIIRS sensor, and compare the derived calibration coefficients for the instrument. Finally, we evaluate the impact of the new calibration approach on the on-orbit performance of the sensor.

77 FR 47375 - Applications for New Awards; Assistive Technology Alternative Financing Program

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

... (AT) they need. In addition, programs such as Medicaid, Medicare, and vocational rehabilitation cannot... sources. Competitive Preference Priorities: Within this absolute priority, we give competitive preference... comment on the proposed absolute and competitive preference priorities under section 437(d)(1)of GEPA. The...

Cytogenetic, cytotoxic and GC-MS studies on concrete and absolute oils from Taif rose, Saudi Arabia.

PubMed

Hagag, Heba A; Bazaid, Salih A; Abdel-Hameed, El-Sayed S; Salman, Mahmood

2014-12-01

Taif rose (Rosa damascena trigintipetala Dieck) is a sort of damask rose, which is considered as one of the most important economic products of Taif. In this study, the authors investigated the possible cytotoxic, genotoxic, antimutagenic and anticancer effect of concrete and absolute rose oils. The results showed that both concrete and absolute rose oils were cytotoxically and genotoxically safe at a dose of 10 μg/ml when tested on cultures of normal human blood lymphocytes. Also, the results showed significant antimutagenic activity at p < 0.001 for absolute rose oil at the same dose level when tested on cultures of normal human blood lymphocytes supplemented with 300 ng/ml mitomycin C (MMC). On the other hand, concrete and absolute oils exerted a cytotoxic activity against two kinds of human cancer cell lines: HepG2 and MCF7. Concrete oil showed cytotoxic activity against HepG2 and MCF7 with a half maximal inhibitory concentration (IC50) of 16.28 and 18.09 μg/ml, respectively, whereas absolute rose oil showed its cytotoxic activity against HepG2 and MCF7 with an IC50 of 24.94 and 19.69, respectively. From this study, it is concluded that concrete and absolute rose oils are cytotoxically and genotoxically safe at a dose of 10 μg/ml when tested on cultures of normal human blood lymphocytes. In addition, absolute oil has an antimutagenic activity at the same dose. Further investigations are needed to study the activity of higher doses of both oils in vitro and in vivo in experimental animals in order to evaluate the capability of using these oils as therapeutic for treatment of some kinds of cancers.

An automated LS(β)- NaI(Tl)(γ) coincidence system as absolute standard for radioactivity measurements.

PubMed

Joseph, Leena; Das, A P; Ravindra, Anuradha; Kulkarni, D B; Kulkarni, M S

2018-07-01

4πβ-γ coincidence method is a powerful and widely used method to determine the absolute activity concentration of radioactive solutions. A new automated liquid scintillator based coincidence system has been designed, developed, tested and established as absolute standard for radioactivity measurements. The automation is achieved using PLC (programmable logic controller) and SCADA (supervisory control and data acquisition). Radioactive solution of 60 Co was standardized to compare the performance of the automated system with proportional counter based absolute standard maintained in the laboratory. The activity concentrations determined using these two systems were in very good agreement; the new automated system can be used for absolute measurement of activity concentration of radioactive solutions. Copyright © 2018. Published by Elsevier Ltd.

Absolute irradiance of the Moon for on-orbit calibration

USGS Publications Warehouse

Stone, T.C.; Kieffer, H.H.; ,

2002-01-01

The recognized need for on-orbit calibration of remote sensing imaging instruments drives the ROLO project effort to characterize the Moon for use as an absolute radiance source. For over 5 years the ground-based ROLO telescopes have acquired spatially-resolved lunar images in 23 VNIR (Moon diameter ???500 pixels) and 9 SWIR (???250 pixels) passbands at phase angles within ??90 degrees. A numerical model for lunar irradiance has been developed which fits hundreds of ROLO images in each band, corrected for atmospheric extinction and calibrated to absolute radiance, then integrated to irradiance. The band-coupled extinction algorithm uses absorption spectra of several gases and aerosols derived from MODTRAN to fit time-dependent component abundances to nightly observations of standard stars. The absolute radiance scale is based upon independent telescopic measurements of the star Vega. The fitting process yields uncertainties in lunar relative irradiance over small ranges of phase angle and the full range of lunar libration well under 0.5%. A larger source of uncertainty enters in the absolute solar spectral irradiance, especially in the SWIR, where solar models disagree by up to 6%. Results of ROLO model direct comparisons to spacecraft observations demonstrate the ability of the technique to track sensor responsivity drifts to sub-percent precision. Intercomparisons among instruments provide key insights into both calibration issues and the absolute scale for lunar irradiance.

Absolute colorimetric characterization of a DSLR camera

NASA Astrophysics Data System (ADS)

Guarnera, Giuseppe Claudio; Bianco, Simone; Schettini, Raimondo

2014-03-01

A simple but effective technique for absolute colorimetric camera characterization is proposed. It offers a large dynamic range requiring just a single, off-the-shelf target and a commonly available controllable light source for the characterization. The characterization task is broken down in two modules, respectively devoted to absolute luminance estimation and to colorimetric characterization matrix estimation. The characterized camera can be effectively used as a tele-colorimeter, giving an absolute estimation of the XYZ data in cd=m2. The user is only required to vary the f - number of the camera lens or the exposure time t, to better exploit the sensor dynamic range. The estimated absolute tristimulus values closely match the values measured by a professional spectro-radiometer.

Absolute Wavelength Calibration of the IDSII Spectrometer for Impurity Ion Velocity Measurements in the MST

NASA Astrophysics Data System (ADS)

Baltzer, M.; Craig, D.; den Hartog, D. J.; Nornberg, M. D.; MST Team

2014-10-01

The MST operates two Ion Doppler Spectrometers (IDS) for high time-resolution passive and active measurements of impurity ion emission. Absolutely calibrated measurements of flow are difficult because the spectrometers record data within 0.3 nm of the line of interest, and commercial calibration lamps do not produce lines in this narrow range . Four calibration methods were investigated. First, emission along the chord bisecting the poloidal plane was measured as it should have no time-averaged Doppler shift. Second, a calibrated CCD spectrometer and the IDSII were used to observe the same plasma from opposing sides so as to measure opposite Doppler shifts. The unshifted line is located halfway between the two opposing measurements. Third, the two fibers of the IDSI were positioned to take absolute flow measurements using opposing views. Substituting the IDSII for one of the IDSI fibers, absolute measurements of flow from the IDSI were used to calibrate the IDSII. Finally, an optical system was designed to filter an ultraviolet LED, providing a known wavelength source within the spectral range covered by the IDSII. The optical train is composed of an air-gapped etalon and fused silica lenses. The quality of calibration for each of these methods is analyzed and their results compared. Preliminary impurity ion velocity measurements are shown. This work has been supported by the US DOE and the NSF.

Neural Sensitivity to Absolute and Relative Anticipated Reward in Adolescents

PubMed Central

Vaidya, Jatin G.; Knutson, Brian; O'Leary, Daniel S.; Block, Robert I.; Magnotta, Vincent

2013-01-01

Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID) task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards). This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude). While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing), adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards) correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity. PMID:23544046

Antiausterity activity of arctigenin enantiomers: importance of (2R,3R)-absolute configuration.

PubMed

Awale, Suresh; Kato, Mamoru; Dibwe, Dya Fita; Li, Feng; Miyoshi, Chika; Esumi, Hiroyasu; Kadota, Shigetoshi; Tezuka, Yasuhiro

2014-01-01

From a MeOH extract of powdered roots of Wikstroemia indica, six dibenzyl-gamma-butyrolactone-type lignans with (2S,3S)-absolute configuration [(+)-arctigenin (1), (+)-matairesinol (2), (+)-trachelogenin (3), (+)-nortrachelogenin (4), (+)-hinokinin (5), and (+)-kusunokinin (6)] were isolated, whereas three dibenzyl-gamma-butyrolactone-type lignans with (2R,3R)-absolute configuration [(-)-arctigenin (1*), (-)-matairesinol (2*), (-)-trachelogenin (3*)] were isolated from Trachelospermum asiaticum. The in vitro preferential cytotoxic activity of the nine compounds was evaluated against human pancreatic PANC-1 cancer cells in nutrient-deprived medium (NDM), but none of the six lignans (1-6) with (2S,3S)-absolute configuration showed preferential cytotoxicity. On the other hand, three lignans (1*-3*) with (2R,3R)-absolute configuration exhibited preferential cytotoxicity in a concentration-dependent manner with PC50 values of 0.54, 6.82, and 5.85 microM, respectively. Furthermore, the effect of (-)- and (+)-arctigenin was evaluated against the activation of Akt, which is a key process in the tolerance to nutrition starvation. Interestingly, only (-)-arctigenin (1*) strongly suppressed the activation of Akt. These results indicate that the (2R,3R)-absolute configuration of (-)-enantiomers should be required for the preferential cytotoxicity through the inhibition of Akt activation.

Concentration Independent Calibration of β-γ Coincidence Detector Using 131mXe and 133Xe

DOE Office of Scientific and Technical Information (OSTI.GOV)

McIntyre, Justin I.; Cooper, Matthew W.; Carman, April J.

Absolute efficiency calibration of radiometric detectors is frequently difficult and requires careful detector modeling and accurate knowledge of the radioactive source used. In the past we have calibrated the b-g coincidence detector of the Automated Radioxenon Sampler/Analyzer (ARSA) using a variety of sources and techniques which have proven to be less than desirable.[1] A superior technique has been developed that uses the conversion-electron (CE) and x-ray coincidence of 131mXe to provide a more accurate absolute gamma efficiency of the detector. The 131mXe is injected directly into the beta cell of the coincident counting system and no knowledge of absolute sourcemore » strength is required. In addition, 133Xe is used to provide a second independent means to obtain the absolute efficiency calibration. These two data points provide the necessary information for calculating the detector efficiency and can be used in conjunction with other noble gas isotopes to completely characterize and calibrate the ARSA nuclear detector. In this paper we discuss the techniques and results that we have obtained.« less

Self-absorption Effects on Alpha-Induced Atmospheric Nitrogen Fluorescence Yield

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bachelor, Paula P.; Jordan, David V.; Harper, Warren W.

2009-12-01

Nitrogen fluorescence induced by alpha, beta and gamma radiation can be used to detect the presence of radioactive contamination in the environment. Successful measurement of fluorescence yield involves a number of factors, including: known fluorescence signal rate during the measurement; the effective alpha spectrum of the radioactive sources used in the measurement; optical attenuation length of the fluorescence signal in air during the measurement; the absolute throughput of the instrumentation; calibration of the instrumentation; and radiation transport modeling of the "effective" array exposure rate given the spectrum of the alpha particles. Field testing of optical instrumentation was conducted to measuremore » the nitrogen fluorescence yield from the alpha radiation generated from americium-241 (241Am) decay. The 241Am test sources were prepared by direct evaporation of ~1 mCi in nitric acid solution, and some solids were visible on the surface of the sources. A laboratory study was conducted with lower activities of 241Am to determine whether the presence of solids on the surface of the sources prepared both by direct evaporation and by electrodeposition onto stainless steel disks produced sufficient self-absorption to cause a decrease in expected fluorescence. Alpha spectroscopy was used to determine the apparent activity of the sources versus the known activity deposited on the surface. Results from the self-absorption laboratory studies were used to correct the activity values in the model and calculate the nitrogen fluorescence generated by the 241Am during the field experiments.« less

Absolute Radiometric Calibration of EUNIS-06

NASA Technical Reports Server (NTRS)

Thomas, R. J.; Rabin, D. M.; Kent, B. J.; Paustian, W.

2007-01-01

The Extreme-Ultraviolet Normal-Incidence Spectrometer (EUNIS) is a soundingrocket payload that obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. Shortly after its successful initial flight last year, a complete end-to-end calibration was carried out to determine the instrument's absolute radiometric response over its Longwave bandpass of 300 - 370A. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibrations of both SOHO/CDS and Hinode/EIS, as well as in three post-flight calibrations of our SERTS sounding rocket payload, the precursor to EUNIS. The unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) had been calibrated to an absolute accuracy of 7% (l-sigma) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is itself a primary radiometric source standard. Scans of the EUNIS aperture were made to determine the instrument's absolute spectral sensitivity to +- 25%, considering all sources of error, and demonstrate that EUNIS-06 was the most sensitive solar E W spectrometer yet flown. The results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted 'insensitive' line ratios. Coordinated observations were made during the EUNIS-06 flight by SOHO/CDS and EIT that will allow re-calibrations of those instruments as well. In addition, future EUNIS flights will provide similar calibration updates for TRACE, Hinode/EIS, and STEREO/SECCHI/EUVI.

Experimental validation of the intrinsic spatial efficiency method over a wide range of sizes for cylindrical sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortiz-Ramŕez, Pablo, E-mail: rapeitor@ug.uchile.cl; Larroquette, Philippe; Camilla, S.

The intrinsic spatial efficiency method is a new absolute method to determine the efficiency of a gamma spectroscopy system for any extended source. In the original work the method was experimentally demonstrated and validated for homogeneous cylindrical sources containing {sup 137}Cs, whose sizes varied over a small range (29.5 mm radius and 15.0 to 25.9 mm height). In this work we present an extension of the validation over a wide range of sizes. The dimensions of the cylindrical sources vary between 10 to 40 mm height and 8 to 30 mm radius. The cylindrical sources were prepared using the referencemore » material IAEA-372, which had a specific activity of 11320 Bq/kg at july 2006. The obtained results were better for the sources with 29 mm radius showing relative bias lesser than 5% and for the sources with 10 mm height showing relative bias lesser than 6%. In comparison with the obtained results in the work where we present the method, the majority of these results show an excellent agreement.« less

Schinus molle: a new source of natural fungitoxicant.

PubMed

Dikshit, A; Naqvi, A A; Husain, A

1986-05-01

The oil of Schinus molle exhibited the maximum fungitoxic activity during the screening of some essential oils against some common storage and animal pathogenic fungi. It showed absolute toxicity against animal pathogens and mild activity against storage fungi. The effective concentrations of the oil varied from 200 to 900 ppm. The toxicity of the oil persisted up to 80 degrees C and 90 days of storage but declined when autoclaved. It withstood heavy inoculum density. The oil exhibited a narrow range of activity and was found to be more effective than Multifungin, an antifungal drug. The oil was characterized by its various physicochemical properties. It was found to comprise 50 constituents. It appeared that some changes in the oil constituents during storage affected its fungitoxic potency.

Using, Seeing, Feeling, and Doing Absolute Value for Deeper Understanding

ERIC Educational Resources Information Center

Ponce, Gregorio A.

2008-01-01

Using sticky notes and number lines, a hands-on activity is shared that anchors initial student thinking about absolute value. The initial point of reference should help students successfully evaluate numeric problems involving absolute value. They should also be able to solve absolute value equations and inequalities that are typically found in…

Receptor modeling for source apportionment of polycyclic aromatic hydrocarbons in urban atmosphere.

PubMed

Singh, Kunwar P; Malik, Amrita; Kumar, Ranjan; Saxena, Puneet; Sinha, Sarita

2008-01-01

This study reports source apportionment of polycyclic aromatic hydrocarbons (PAHs) in particulate depositions on vegetation foliages near highway in the urban environment of Lucknow city (India) using the principal components analysis/absolute principal components scores (PCA/APCS) receptor modeling approach. The multivariate method enables identification of major PAHs sources along with their quantitative contributions with respect to individual PAH. The PCA identified three major sources of PAHs viz. combustion, vehicular emissions, and diesel based activities. The PCA/APCS receptor modeling approach revealed that the combustion sources (natural gas, wood, coal/coke, biomass) contributed 19-97% of various PAHs, vehicular emissions 0-70%, diesel based sources 0-81% and other miscellaneous sources 0-20% of different PAHs. The contributions of major pyrolytic and petrogenic sources to the total PAHs were 56 and 42%, respectively. Further, the combustion related sources contribute major fraction of the carcinogenic PAHs in the study area. High correlation coefficient (R2 > 0.75 for most PAHs) between the measured and predicted concentrations of PAHs suggests for the applicability of the PCA/APCS receptor modeling approach for estimation of source contribution to the PAHs in particulates.

Impact of the vaginal applicator and dummy pellets on the dosimetry parameters of Cs-137 brachytherapy source.

PubMed

Sina, Sedigheh; Faghihi, Reza; Meigooni, Ali S; Mehdizadeh, Simin; Mosleh Shirazi, M Amin; Zehtabian, Mehdi

2011-05-19

In this study, dose rate distribution around a spherical 137Cs pellet source, from a low-dose-rate (LDR) Selectron remote afterloading system used in gynecological brachytherapy, has been determined using experimental and Monte Carlo simulation techniques. Monte Carlo simulations were performed using MCNP4C code, for a single pellet source in water medium and Plexiglas, and measurements were performed in Plexiglas phantom material using LiF TLD chips. Absolute dose rate distribution and the dosimetric parameters, such as dose rate constant, radial dose functions, and anisotropy functions, were obtained for a single pellet source. In order to investigate the effect of the applicator and surrounding pellets on dosimetric parameters of the source, the simulations were repeated for six different arrangements with a single active source and five non-active pellets inside central metallic tubing of a vaginal cylindrical applicator. In commercial treatment planning systems (TPS), the attenuation effects of the applicator and inactive spacers on total dose are neglected. The results indicate that this effect could lead to overestimation of the calculated F(r,θ), by up to 7% along the longitudinal axis of the applicator, especially beyond the applicator tip. According to the results obtained in this study, in a real situation in treatment of patients using cylindrical vaginal applicator and using several active pellets, there will be a large discrepancy between the result of superposition and Monte Carlo simulations.

Neutron activation analysis of certified samples by the absolute method

NASA Astrophysics Data System (ADS)

Kadem, F.; Belouadah, N.; Idiri, Z.

2015-07-01

The nuclear reactions analysis technique is mainly based on the relative method or the use of activation cross sections. In order to validate nuclear data for the calculated cross section evaluated from systematic studies, we used the neutron activation analysis technique (NAA) to determine the various constituent concentrations of certified samples for animal blood, milk and hay. In this analysis, the absolute method is used. The neutron activation technique involves irradiating the sample and subsequently performing a measurement of the activity of the sample. The fundamental equation of the activation connects several physical parameters including the cross section that is essential for the quantitative determination of the different elements composing the sample without resorting to the use of standard sample. Called the absolute method, it allows a measurement as accurate as the relative method. The results obtained by the absolute method showed that the values are as precise as the relative method requiring the use of standard sample for each element to be quantified.

Absolute calibration of sniffer probes on Wendelstein 7-X

NASA Astrophysics Data System (ADS)

Moseev, D.; Laqua, H. P.; Marsen, S.; Stange, T.; Braune, H.; Erckmann, V.; Gellert, F.; Oosterbeek, J. W.

2016-08-01

Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of the Wendelstein 7-X empty vacuum vessel. Normalized absolute calibration coefficients agree with the cross-calibration coefficients that are obtained by the direct measurements, indicating that the measured absolute calibration coefficients and stray radiation levels in the vessel are valid. Close to the launcher, the stray radiation in the empty vessel reaches power levels up to 340 kW/m2 per MW injected beam power. Furthest away from the launcher, i.e., half a toroidal turn, still 90 kW/m2 per MW injected beam power is measured.

Absolute calibration of sniffer probes on Wendelstein 7-X.

PubMed

Moseev, D; Laqua, H P; Marsen, S; Stange, T; Braune, H; Erckmann, V; Gellert, F; Oosterbeek, J W

2016-08-01

Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of the Wendelstein 7-X empty vacuum vessel. Normalized absolute calibration coefficients agree with the cross-calibration coefficients that are obtained by the direct measurements, indicating that the measured absolute calibration coefficients and stray radiation levels in the vessel are valid. Close to the launcher, the stray radiation in the empty vessel reaches power levels up to 340 kW/m(2) per MW injected beam power. Furthest away from the launcher, i.e., half a toroidal turn, still 90 kW/m(2) per MW injected beam power is measured.

How calibration and reference spectra affect the accuracy of absolute soft X-ray solar irradiance measured by the SDO/EVE/ESP during high solar activity

NASA Astrophysics Data System (ADS)

Didkovsky, Leonid; Wieman, Seth; Woods, Thomas

2016-10-01

The Extreme ultraviolet Spectrophotometer (ESP), one of the channels of SDO's Extreme ultraviolet Variability Experiment (EVE), measures solar irradiance in several EUV and soft x-ray (SXR) bands isolated using thin-film filters and a transmission diffraction grating, and includes a quad-diode detector positioned at the grating zeroth-order to observe in a wavelength band from about 0.1 to 7.0 nm. The quad diode signal also includes some contribution from shorter wavelength in the grating's first-order and the ratio of zeroth-order to first-order signal depends on both source geometry, and spectral distribution. For example, radiometric calibration of the ESP zeroth-order at the NIST SURF BL-2 with a near-parallel beam provides a different zeroth-to-first-order ratio than modeled for solar observations. The relative influence of "uncalibrated" first-order irradiance during solar observations is a function of the solar spectral irradiance and the locations of large Active Regions or solar flares. We discuss how the "uncalibrated" first-order "solar" component and the use of variable solar reference spectra affect determination of absolute SXR irradiance which currently may be significantly overestimated during high solar activity.

Effects of Ambient Temperature and Relative Humidity on Subsurface Defect Detection in Concrete Structures by Active Thermal Imaging.

PubMed

Tran, Quang Huy; Han, Dongyeob; Kang, Choonghyun; Haldar, Achintya; Huh, Jungwon

2017-07-26

Active thermal imaging is an effective nondestructive technique in the structural health monitoring field, especially for concrete structures not exposed directly to the sun. However, the impact of meteorological factors on the testing results is considerable and should be studied in detail. In this study, the impulse thermography technique with halogen lamps heat sources is used to detect defects in concrete structural components that are not exposed directly to sunlight and not significantly affected by the wind, such as interior bridge box-girders and buildings. To consider the effect of environment, ambient temperature and relative humidity, these factors are investigated in twelve cases of testing on a concrete slab in the laboratory, to minimize the influence of wind. The results showed that the absolute contrast between the defective and sound areas becomes more apparent with an increase of ambient temperature, and it increases at a faster rate with large and shallow delaminations than small and deep delaminations. In addition, the absolute contrast of delamination near the surface might be greater under a highly humid atmosphere. This study indicated that the results obtained from the active thermography technique will be more apparent if the inspection is conducted on a day with high ambient temperature and humidity.

Absolute Distance Measurement with the MSTAR Sensor

NASA Technical Reports Server (NTRS)

Lay, Oliver P.; Dubovitsky, Serge; Peters, Robert; Burger, Johan; Ahn, Seh-Won; Steier, William H.; Fetterman, Harrold R.; Chang, Yian

2003-01-01

The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. The sensor uses a single laser in conjunction with fast phase modulators and low frequency detectors. We describe the design of the system - the principle of operation, the metrology source, beamlaunching optics, and signal processing - and show results for target distances up to 1 meter. We then demonstrate how the system can be scaled to kilometer-scale distances.

Acute effects of exercise on mood and EEG activity in healthy young subjects: a systematic review.

PubMed

Lattari, Eduardo; Portugal, Eduardo; Moraes, Helena; Machado, Sérgio; Santos, Tony M; Deslandes, Andrea C

2014-01-01

Electroencephalography has been used to establish the relationship among cortical activity, exercise and mood, such as asymmetry, absolute and relative power. The purpose of this study was to systematically review the influence of cortical activity on mood state induced by exercise. The Preferred Reporting Items in Systematic reviews and Meta-Analyses was followed in this study. The studies were retrieved from MEDLINE/PubMed, ISI Web of Knowledge and SciELO. Search was conducted in all databases using the following terms: EEG asymmetry, sLORETA, exercise, with affect, mood and emotions. Based on the defined criteria, a total of 727 articles were found in the search conducted in the literature (666 in Pubmed, 54 in ISI Web of Science, 2 in SciELO and 5 in other data sources). Total of 11 studies were selected which properly met the criteria for this review. Nine out of 11 studies used the frontal asymmetry, four used absolute and relative power and one used sLORETA. With regard to changes in cortical activity and mood induced by exercise, six studies attributed this result to different intensities, one to duration, one to type of exercise and one to fitness level. In general, EEG measures showed contradictory evidence of its ability to predict or modulate psychological mood states through exercise intervention.

Convex Curved Crystal Spectograph for Pulsed Plasma Sources.

DTIC Science & Technology

The geometry of a convex curved crystal spectrograph as applied to pulsed plasma sources is presented. Also presented are data from the dense plasma focus with particular emphasis on the absolute intensity of line radiations.

Furanodictine A and B: amino sugar analogues produced by cellular slime mold Dictyostelium discoideum showing neuronal differentiation activity.

PubMed

Kikuchi, H; Saito, Y; Komiya, J; Takaya, Y; Honma, S; Nakahata, N; Ito, A; Oshima, Y

2001-10-19

We investigated the constituents of Dictyostelium discoideum to clarify the diversity of secondary metabolites of Dictyostelium cellular slime molds and to explore biologically active substances that could be useful in the development of novel drugs. From a methanol extract of the multicellular fruit body of D. discoideum, we isolated two novel amino sugar analogues, furanodictine A (1) and B (2). They are the first 3,6-anhydrosugars to be isolated from natural sources. Their relative structures were elucidated by spectral means, and the absolute configurations were confirmed by asymmetric syntheses of 1 and 2. These furanodictines potently induce neuronal differentiation of rat pheochromocytoma (PC-12) cells.

A comparison of absolute calibrations of a radiation thermometer based on a monochromator and a tunable source

NASA Astrophysics Data System (ADS)

Keawprasert, T.; Anhalt, K.; Taubert, D. R.; Sperling, A.; Schuster, M.; Nevas, S.

2013-09-01

An LP3 radiation thermometer was absolutely calibrated at a newly developed monochromator-based set-up and the TUneable Lasers in Photometry (TULIP) facility of PTB in the wavelength range from 400 nm to 1100 nm. At both facilities, the spectral radiation of the respective sources irradiates an integrating sphere, thus generating uniform radiance across its precision aperture. The spectral irradiance of the integrating sphere is determined via an effective area of a precision aperture and a Si trap detector, traceable to the primary cryogenic radiometer of PTB. Due to the limited output power from the monochromator, the absolute calibration was performed with the measurement uncertainty of 0.17 % (k = 1), while the respective uncertainty at the TULIP facility is 0.14 %. Calibration results obtained by the two facilities were compared in terms of spectral radiance responsivity, effective wavelength and integral responsivity. It was found that the measurement results in integral responsivity at the both facilities are in agreement within the expanded uncertainty (k = 2). To verify the calibration accuracy, the absolutely calibrated radiation thermometer was used to measure the thermodynamic freezing temperatures of the PTB gold fixed-point blackbody.

A new method to calibrate the absolute sensitivity of a soft X-ray streak camera

NASA Astrophysics Data System (ADS)

Yu, Jian; Liu, Shenye; Li, Jin; Yang, Zhiwen; Chen, Ming; Guo, Luting; Yao, Li; Xiao, Shali

2016-12-01

In this paper, we introduce a new method to calibrate the absolute sensitivity of a soft X-ray streak camera (SXRSC). The calibrations are done in the static mode by using a small laser-produced X-ray source. A calibrated X-ray CCD is used as a secondary standard detector to monitor the X-ray source intensity. In addition, two sets of holographic flat-field grating spectrometers are chosen as the spectral discrimination systems of the SXRSC and the X-ray CCD. The absolute sensitivity of the SXRSC is obtained by comparing the signal counts of the SXRSC to the output counts of the X-ray CCD. Results show that the calibrated spectrum covers the range from 200 eV to 1040 eV. The change of the absolute sensitivity in the vicinity of the K-edge of the carbon can also be clearly seen. The experimental values agree with the calculated values to within 29% error. Compared with previous calibration methods, the proposed method has several advantages: a wide spectral range, high accuracy, and simple data processing. Our calibration results can be used to make quantitative X-ray flux measurements in laser fusion research.

Variation in the Gender Gap in Inactive and Active Life Expectancy by the Definition of Inactivity Among Older Adults.

PubMed

Malhotra, Rahul; Chan, Angelique; Ajay, Shweta; Ma, Stefan; Saito, Yasuhiko

2016-10-01

To assess variation in gender gap (female-male) in inactive life expectancy (IALE) and active life expectancy (ALE) by definition of inactivity. Inactivity, among older Singaporeans, was defined as follows: Scenario 1-health-related difficulty in activities of daily living (ADLs); Scenario 2-health-related difficulty in ADLs/instrumental ADLs (IADLs); Scenario 3-health-related difficulty in ADLs/IADLs or non-health-related non-performance of IADLs. Multistate life tables computed IALE and ALE at age 60, testing three hypotheses: In all scenarios, life expectancy, absolute and relative IALE, and absolute ALE are higher for females (Hypothesis 1 [H1]); gender gap in absolute and relative IALE expands, and in absolute ALE, it contracts in Scenario 2 versus 1 (Hypothesis 2 [H2]); gender gap in absolute and relative IALE decreases, and in absolute ALE, it increases in Scenario 3 versus 2 (Hypothesis 3 [H3]). H1 was supported in Scenarios 1 and 3 but not Scenario 2. Both H2 and H3 were supported. Definition of inactivity influences gender gap in IALE and ALE. © The Author(s) 2016.

Effect of γ-irradiation on the temperature coefficient of surface resistivity of two-dimensional island platinum films

NASA Astrophysics Data System (ADS)

Bishay, A. G.; El-Gamal, S.

2011-05-01

Three sets (A, B and C) of two-dimensional island platinum films (2D-I(Pt)Fs) were prepared via the thermal evaporation technique, where the substrates are corning 7059 glass slides. The mass thickness ( d m) of the films of different sets is 5, 10 and 20 Å, respectively. The Pt films were exposed to γ-rays from 137Cs (0.662 MeV) radiation source of dose rate 0.5 Gy/min. and the different doses are 100, 200, 300, 500 and 700 Gy. The dependence of the surface resistivity ( ρ) on temperature over the range of 100-300 K was undertaken at different d m and doses then the temperature coefficient of surface resistivity ( α) was deduced. It was found that; (i) for particular d m and T, the absolute value of α decreases as the dose increases (ii) for particular dose and T, the absolute value of α decreases as d m increases (iii) for particular dose and d m, the absolute value of α decreases as T increases. Qualitative interpretation for the results was offered on the ground that the electrons transfer among islands takes place by the activated tunneling mechanism and the γ-irradiation has changed the shape of islands from spherical to prolate spheroid.

Schinus molle: a new source of natural fungitoxicant.

PubMed Central

Dikshit, A; Naqvi, A A; Husain, A

1986-01-01

The oil of Schinus molle exhibited the maximum fungitoxic activity during the screening of some essential oils against some common storage and animal pathogenic fungi. It showed absolute toxicity against animal pathogens and mild activity against storage fungi. The effective concentrations of the oil varied from 200 to 900 ppm. The toxicity of the oil persisted up to 80 degrees C and 90 days of storage but declined when autoclaved. It withstood heavy inoculum density. The oil exhibited a narrow range of activity and was found to be more effective than Multifungin, an antifungal drug. The oil was characterized by its various physicochemical properties. It was found to comprise 50 constituents. It appeared that some changes in the oil constituents during storage affected its fungitoxic potency. PMID:3729389

Absolute Nuv magnitudes of Gaia DR1 astrometric stars and a search for hot companions in nearby systems

NASA Astrophysics Data System (ADS)

Makarov, V. V.

2017-10-01

Accurate parallaxes from Gaia DR1 (TGAS) are combined with GALEX visual Nuv magnitudes to produce absolute Mnuv magnitudes and an ultraviolet HR diagram for a large sample of astrometric stars. A functional fit is derived of the lower envelope main sequence of the nearest 1403 stars (distance <40 pc), which should be reddening-free. Using this empirical fit, 50 nearby stars are selected with significant Nuv excess. These are predominantly late K and early M dwarfs, often associated with X-ray sources, and showing other manifestations of magnetic activity. The sample may include systems with hidden white dwarfs, stars younger than the Pleiades, or, most likely, tight interacting binaries of the BY Dra-type. A separate collection of 40 stars with precise trigonometric parallaxes and Nuv-G colors bluer than 2 mag is presented. It includes several known novae, white dwarfs, and binaries with hot subdwarf (sdOB) components, but most remain unexplored.

Calibration of a time-resolved hard-x-ray detector using radioactive sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoeckl, C., E-mail: csto@lle.rochester.edu; Theobald, W.; Regan, S. P.

A four-channel, time-resolved, hard x-ray detector (HXRD) has been operating at the Laboratory for Laser Energetics for more than a decade. The slope temperature of the hot-electron population in direct-drive inertial confinement fusion experiments is inferred by recording the hard x-ray radiation generated in the interaction of the electrons with the target. Measuring the energy deposited by hot electrons requires an absolute calibration of the hard x-ray detector. A novel method to obtain an absolute calibration of the HXRD using single photons from radioactive sources was developed, which uses a thermoelectrically cooled, low-noise, charge-sensitive amplifier.

Frequency Measurements of Superradiance from the Strontium Clock Transition

NASA Astrophysics Data System (ADS)

Norcia, Matthew A.; Cline, Julia R. K.; Muniz, Juan A.; Robinson, John M.; Hutson, Ross B.; Goban, Akihisa; Marti, G. Edward; Ye, Jun; Thompson, James K.

2018-04-01

We present the first characterization of the spectral properties of superradiant light emitted from the ultranarrow, 1-mHz-linewidth optical clock transition in an ensemble of cold Sr 87 atoms. Such a light source has been proposed as a next-generation active atomic frequency reference, with the potential to enable high-precision optical frequency references to be used outside laboratory environments. By comparing the frequency of our superradiant source to that of a state-of-the-art cavity-stabilized laser and optical lattice clock, we observe a fractional Allan deviation of 6.7 (1 )×10-16 at 1 s of averaging, establish absolute accuracy at the 2-Hz (4 ×10-15 fractional frequency) level, and demonstrate insensitivity to key environmental perturbations.

SU-G-BRB-15: Verifications of Absolute and Relative Dosimetry of a Novel Stereotactic Breast Device: GammaPodTM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Becker, S; Mossahebi, S; Yi, B

Purpose: A dedicated stereotactic breast radiotherapy device, GammaPod, was developed to treat early stage breast cancer. The first clinical unit was installed and commissioned at University of Maryland. We report our methodology of absolute dosimetry in multiple calibration conditions and dosimetric verifications of treatment plans produced by the system. Methods: GammaPod unit is comprised of a rotating hemi-spherical source carrier containing 36 Co-60 sources and a concentric tungsten collimator providing beams of 15 and 25 mm. Absolute dose calibration formalism was developed with modifications to AAPM protocols for unique geometry and different calibration medium (acrylic, polyethylene or liquid water). Breastmore » cup-size specific and collimator output factors were measured and verified with respect to Monte-Carlo simulations for single isocenter plans. Multiple isocenter plans were generated for various target size, location and cup-sizes in phantoms and 20 breast cancer patients images. Stereotactic mini-farmer chamber, OSL and TLD detectors as well as radio-chromic films were used for dosimetric measurements. Results: At the time of calibration (1/14/2016), absolute dose rate of the GammaPod was established to be 2.10 Gy/min in acrylic for 25 mm for sources installed in March 2011. Output factor for 15 mm collimator was measured to be 0.950. Absolute dose calibration was independently verified by IROC-Houston with a TLD/Institution ratio of 0.99. Cup size specific output measurements in liquid water for single isocenter were found to be within 3.0% of MC simulations. Point-dose measurements of multiple isocenter treatment plans were found to be within −1.0 ± 1.2 % of treatment planning system while 2-dimensional gamma analysis yielded a pass rate of 97.9 ± 2.2 % using gamma criteria of 3% and 2mm. Conclusion: The first GammaPod treatment unit for breast stereotactic radiotherapy was successfully installed, calibrated and commissioned for patient treatments. An absolute dosimetry and dosimetric verification protocols were successfully created.« less

Chandra X-Ray Observations of the Two Brightest Unidentified High Galactic Latitude Fermi-LAT Gamma-Ray Sources

NASA Technical Reports Server (NTRS)

Cheung, C. C.; Donato, D.; Gehrels, N.; Sokolovsky, K. V.; Giroletti, M.

2012-01-01

We present Chandra ACIS-I X-ray observations of 0FGL J1311.9-3419 and 0FGL J1653.4-0200, the two brightest high Galactic latitude (absolute value (beta) >10 deg) gamma-ray sources from the three-month Fermi Large Area Telescope (LAT) bright source list that are still unidentified. Both were also detected previously by EGRET, and despite dedicated multi-wavelength follow-up, they are still not associated with established classes of gamma-ray emitters like pulsars or radio-loud active galactic nuclei. X-ray sources found in the ACIS-I fields of view are cataloged, and their basic properties are determined. These are discussed as candidate counterparts to 0FGL J1311.9-3419 and 0FGL J1653.4-0200, with particular emphasis on the brightest of the 9 and 13 Chandra sources detected within the respective Fermi-LAT 95% confidence regions. Further follow-up studies, including optical photometric and spectroscopic observations, are necessary to identify these X-ray candidate counterparts in order to ultimately reveal the nature of these enigmatic gamma-ray objects.

Evaluation of absolute measurement using a 4π plastic scintillator for the 4πβ-γ coincidence counting method.

PubMed

Unno, Y; Sanami, T; Sasaki, S; Hagiwara, M; Yunoki, A

2018-04-01

Absolute measurement by the 4πβ-γ coincidence counting method was conducted by two photomultipliers facing across a plastic scintillator to be focused on β ray counting efficiency. The detector was held with a through-hole-type NaI(Tl) detector. The results include absolutely determined activity and its uncertainty especially about extrapolation. A comparison between the obtained and known activities showed agreement within their uncertainties. Copyright © 2017 Elsevier Ltd. All rights reserved.

The PMA Catalogue: 420 million positions and absolute proper motions

NASA Astrophysics Data System (ADS)

Akhmetov, V. S.; Fedorov, P. N.; Velichko, A. B.; Shulga, V. M.

2017-07-01

We present a catalogue that contains about 420 million absolute proper motions of stars. It was derived from the combination of positions from Gaia DR1 and 2MASS, with a mean difference of epochs of about 15 yr. Most of the systematic zonal errors inherent in the 2MASS Catalogue were eliminated before deriving the absolute proper motions. The absolute calibration procedure (zero-pointing of the proper motions) was carried out using about 1.6 million positions of extragalactic sources. The mean formal error of the absolute calibration is less than 0.35 mas yr-1. The derived proper motions cover the whole celestial sphere without gaps for a range of stellar magnitudes from 8 to 21 mag. In the sky areas where the extragalactic sources are invisible (the avoidance zone), a dedicated procedure was used that transforms the relative proper motions into absolute ones. The rms error of proper motions depends on stellar magnitude and ranges from 2-5 mas yr-1 for stars with 10 mag < G < 17 mag to 5-10 mas yr-1 for faint ones. The present catalogue contains the Gaia DR1 positions of stars for the J2015 epoch. The system of the PMA proper motions does not depend on the systematic errors of the 2MASS positions, and in the range from 14 to 21 mag represents an independent realization of a quasi-inertial reference frame in the optical and near-infrared wavelength range. The Catalogue also contains stellar magnitudes taken from the Gaia DR1 and 2MASS catalogues. A comparison of the PMA proper motions of stars with similar data from certain recent catalogues has been undertaken.

Determining the 13C(α, n)16O absolute cross section through the concurrent application of ANC and THM and astrophysical consequences for the s-process in AGB-LMSs.

NASA Astrophysics Data System (ADS)

Trippella, Oscar; La Cognata, Marco

2018-01-01

The 13C(α, n)16O reaction is considered to be the most important neutron source for the s-process main component in low-mass asymptotic giant branch stars. No direct experimental data exist at very low energies and measurements performed through direct techniques show inconsistent results, mostly in their absolute values. In this context, we reversed the usual normalization procedure combining two indirect approaches, the asymptotic normalization coefficient and the Trojan Horse Method, to unambiguously determine the absolute value of the 13C(α, n)16O astrophysical S(E)-factor in the most relevant energy-region for astrophysics. Adopting the new reaction rate for the n-source in the NEWTON s-process nucleosynthesis code, astrophysical calculations show only limited variations, less than 1%, for those nuclei whose production is considered to be totally due to slow neutron captures.

Characterization of the graphite pile as a source of thermal neutrons

NASA Astrophysics Data System (ADS)

Vykydal, Zdenek; Králík, Miloslav; Jančář, Aleš; Kopecký, Zdeněk; Dressler, Jan; Veškrna, Martin

2015-11-01

A new graphite pile designed to serve as a standard source of thermal neutrons has been built at the Czech Metrology Institute. Actual dimensions of the pile are 1.95 m (W)×1.95 m (L)×2.0 m (H). At its center, there is a measurement channel whose dimensions are 0.4 m×0.4 m×1.25 m (depth). The channel is equipped with a calibration bench, which allows reproducible placement of the tested/calibrated device. At a distance of 80 cm from the channel axis, six holes are symmetrically located allowing the placement of radionuclide neutron sources of Pu-Be and/or Am-Be type. Spatial distribution of thermal neutron fluence in the cavity was calculated in detail with the MCNP neutron transport code. Experimentally, it was measured with two active detectors: a small 3He proportional detector by the French company LMT, type 0.5 NH 1/1 KF, and a silicon pixel detector Timepix with 10B converter foil. The relative values of thermal neutron fluence rate obtained with active detectors were converted to absolute ones using thermal neutron fluence rates measured by means of gold foil activation. The quality of thermal neutron field was characterized by the cadmium ratio.

Electric discharge in water as a source of UV radiation, ozone and hydrogen peroxide

NASA Astrophysics Data System (ADS)

Anpilov, A. M.; Barkhudarov, E. M.; Bark, Yu B.; Zadiraka, Yu V.; Christofi, M.; Kozlov, Yu N.; Kossyi, I. A.; Kop'ev, V. A.; Silakov, V. P.; Taktakishvili, M. I.; Temchin, S. M.

2001-03-01

Results are presented from investigations of multispark electric discharge in water excited along multielectrode metal-dielectric systems with gas supply into the interelectrode gaps. The intensity distribution of discharge radiation in the region covering the biologically active soft UV (190≤λ≤430 nm) has been determined and the absolute number of quanta in this wavelength interval has been measured. The potentiality of the slipping surface discharge in water for its disinfection is analysed. The energy expenditure for water cleansing is estimated to be as low as ~10-4 kWh l-1.

Design and Fabrication of Cherenkov Counters for the Detection of SNM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, Anna S.; Lanza, Richard; Galaitsis, Anthony

2011-12-13

The need for large-size detectors for long-range active interrogation (AI) detection of SNM has generated interest in water-based detector technologies. Water Cherenkov Detectors (WCD) were selected for this research because of their transportability, scalability, and an inherent energy threshold. The detector design and analysis was completed using the Geant4 toolkit. It was demonstrated both computationally and experimentally that it is possible to use WCD to detect and characterize gamma rays. Absolute efficiency of the detector (with no energy cuts applied) was determined to be around 30% for a {sup 60}Co source.

Energy cost of activities in preschool-aged children

USDA-ARS?s Scientific Manuscript database

The absolute energy cost of activities in children increase with age due to greater muscle mass and physical capability associated with growth and developmental maturation; however, there is a paucity of data in preschool-aged children. Study aims were 1) to describe absolute and relative energy cos...

40 CFR Appendix D to Part 52 - Determination of Sulfur Dioxide Emissions From Stationary Sources by Continuous Monitors

Code of Federal Regulations, 2012 CFR

2012-07-01

... confidence interval using Equations D-1 and D-2. Report the zero drift as the sum of the absolute mean value... confidence interval using Equations D-1 and D-2. Report the zero drift as the sum of the absolute mean and... operation when the pollutant concentration at the time for the measurement is zero. 1.6Calibration Drift...

40 CFR Appendix D to Part 52 - Determination of Sulfur Dioxide Emissions From Stationary Sources by Continuous Monitors

Code of Federal Regulations, 2014 CFR

2014-07-01

... confidence interval using Equations D-1 and D-2. Report the zero drift as the sum of the absolute mean value... confidence interval using Equations D-1 and D-2. Report the zero drift as the sum of the absolute mean and... operation when the pollutant concentration at the time for the measurement is zero. 1.6Calibration Drift...

40 CFR Appendix D to Part 52 - Determination of Sulfur Dioxide Emissions From Stationary Sources by Continuous Monitors

Code of Federal Regulations, 2013 CFR

2013-07-01

... confidence interval using Equations D-1 and D-2. Report the zero drift as the sum of the absolute mean value... confidence interval using Equations D-1 and D-2. Report the zero drift as the sum of the absolute mean and... operation when the pollutant concentration at the time for the measurement is zero. 1.6Calibration Drift...

Improved absolute calibration of LOPES measurements and its impact on the comparison with REAS 3.11 and CoREAS simulations

NASA Astrophysics Data System (ADS)

Apel, W. D.; Arteaga-Velázquez, J. C.; Bähren, L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Cantoni, E.; Chiavassa, A.; Daumiller, K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Fuchs, B.; Gemmeke, H.; Grupen, C.; Haungs, A.; Heck, D.; Hiller, R.; Hörandel, J. R.; Horneffer, A.; Huber, D.; Huege, T.; Isar, P. G.; Kampert, K.-H.; Kang, D.; Krömer, O.; Kuijpers, J.; Link, K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.; Melissas, M.; Morello, C.; Nehls, S.; Oehlschläger, J.; Palmieri, N.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth, M.; Rühle, C.; Saftoiu, A.; Schieler, H.; Schmidt, A.; Schoo, S.; Schröder, F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Weindl, A.; Wochele, J.; Zabierowski, J.; Zensus, J. A.

2016-02-01

LOPES was a digital antenna array detecting the radio emission of cosmic-ray air showers. The calibration of the absolute amplitude scale of the measurements was done using an external, commercial reference source, which emits a frequency comb with defined amplitudes. Recently, we obtained improved reference values by the manufacturer of the reference source, which significantly changed the absolute calibration of LOPES. We reanalyzed previously published LOPES measurements, studying the impact of the changed calibration. The main effect is an overall decrease of the LOPES amplitude scale by a factor of 2.6 ± 0.2, affecting all previously published values for measurements of the electric-field strength. This results in a major change in the conclusion of the paper 'Comparing LOPES measurements of air-shower radio emission with REAS 3.11 and CoREAS simulations' published by Apel et al. (2013) : With the revised calibration, LOPES measurements now are compatible with CoREAS simulations, but in tension with REAS 3.11 simulations. Since CoREAS is the latest version of the simulation code incorporating the current state of knowledge on the radio emission of air showers, this new result indicates that the absolute amplitude prediction of current simulations now is in agreement with experimental data.

Ratio of He{sup 2+}/He{sup +} from 80 to 800 eV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samson, J.A.R.; Stolte, W.C.; He, Z.X.

1997-04-01

The importance of studying the double ionization of He by single photons lies in the fact that He presents the simplest structure for the study of electron correlation processes. Even so it has proved a challenging problem to understand and describe theoretically. Surprisingly, it has also proved difficult to agree experimentally on the absolute values of the He{sup 2+}/He{sup +} ratios. The availability of new synchrotron facilities with high intensity light outputs have increased the experimental activity in this area. However, by the very nature of those continuum sources systematic errors occur due to the presence of higher order spectramore » and great care must be exercised. The authors have measured the He{sup 2+}/He{sup +} ratios over a period of 5 years, the last three at the ALS utilizing beamlines 9.0.1 and 6.3.2. The sources of systematic errors that they have considered include: scattered light, higher order spectra, detector sensitivity to differently charged ions, discriminator levels in the counting equipment, gas purity, and stray electrons from filters and metal supports. The measurements have been made at three different synchrotron facilities with different types of monochromators and their potential for different sources of systematic errors. However, the authors data from all these different measurements agree within a few percent of each other. From the above results and their precision total photoionization cross sections for He, the authors can obtain the absolute photoionization cross section for He{sup 2+}. They find similar near perfect agreement with several of the latest calculations.« less

Fully distributed absolute blood flow velocity measurement for middle cerebral arteries using Doppler optical coherence tomography

PubMed Central

Qi, Li; Zhu, Jiang; Hancock, Aneeka M.; Dai, Cuixia; Zhang, Xuping; Frostig, Ron D.; Chen, Zhongping

2016-01-01

Doppler optical coherence tomography (DOCT) is considered one of the most promising functional imaging modalities for neuro biology research and has demonstrated the ability to quantify cerebral blood flow velocity at a high accuracy. However, the measurement of total absolute blood flow velocity (BFV) of major cerebral arteries is still a difficult problem since it is related to vessel geometry. In this paper, we present a volumetric vessel reconstruction approach that is capable of measuring the absolute BFV distributed along the entire middle cerebral artery (MCA) within a large field-of-view. The Doppler angle at each point of the MCA, representing the vessel geometry, is derived analytically by localizing the artery from pure DOCT images through vessel segmentation and skeletonization. Our approach could achieve automatic quantification of the fully distributed absolute BFV across different vessel branches. Experiments on rodents using swept-source optical coherence tomography showed that our approach was able to reveal the consequences of permanent MCA occlusion with absolute BFV measurement. PMID:26977365

Fully distributed absolute blood flow velocity measurement for middle cerebral arteries using Doppler optical coherence tomography.

PubMed

Qi, Li; Zhu, Jiang; Hancock, Aneeka M; Dai, Cuixia; Zhang, Xuping; Frostig, Ron D; Chen, Zhongping

2016-02-01

Doppler optical coherence tomography (DOCT) is considered one of the most promising functional imaging modalities for neuro biology research and has demonstrated the ability to quantify cerebral blood flow velocity at a high accuracy. However, the measurement of total absolute blood flow velocity (BFV) of major cerebral arteries is still a difficult problem since it is related to vessel geometry. In this paper, we present a volumetric vessel reconstruction approach that is capable of measuring the absolute BFV distributed along the entire middle cerebral artery (MCA) within a large field-of-view. The Doppler angle at each point of the MCA, representing the vessel geometry, is derived analytically by localizing the artery from pure DOCT images through vessel segmentation and skeletonization. Our approach could achieve automatic quantification of the fully distributed absolute BFV across different vessel branches. Experiments on rodents using swept-source optical coherence tomography showed that our approach was able to reveal the consequences of permanent MCA occlusion with absolute BFV measurement.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moseev, D., E-mail: dmitry.moseev@ipp.mpg.de; Laqua, H. P.; Marsen, S.

Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of the Wendelstein 7-X empty vacuum vessel. Normalized absolute calibration coefficients agree with the cross-calibration coefficients that are obtained by the direct measurements, indicating that the measured absolute calibration coefficients and stray radiation levels in the vessel are valid. Close to the launcher, the stray radiation in the empty vessel reaches power levels up tomore » 340 kW/m{sup 2} per MW injected beam power. Furthest away from the launcher, i.e., half a toroidal turn, still 90 kW/m{sup 2} per MW injected beam power is measured.« less

Spectral purity and tunability of terahertz quantum cascade laser sources based on intracavity difference-frequency generation.

PubMed

Consolino, Luigi; Jung, Seungyong; Campa, Annamaria; De Regis, Michele; Pal, Shovon; Kim, Jae Hyun; Fujita, Kazuue; Ito, Akio; Hitaka, Masahiro; Bartalini, Saverio; De Natale, Paolo; Belkin, Mikhail A; Vitiello, Miriam Serena

2017-09-01

Terahertz sources based on intracavity difference-frequency generation in mid-infrared quantum cascade lasers (THz DFG-QCLs) have recently emerged as the first monolithic electrically pumped semiconductor sources capable of operating at room temperature across the 1- to 6-THz range. Despite tremendous progress in power output, which now exceeds 1 mW in pulsed and 10 μW in continuous-wave regimes at room temperature, knowledge of the major figure of merits of these devices for high-precision spectroscopy, such as spectral purity and absolute frequency tunability, is still lacking. By exploiting a metrological grade system comprising a terahertz frequency comb synthesizer, we measure, for the first time, the free-running emission linewidth (LW), the tuning characteristics, and the absolute center frequency of individual emission lines of these sources with an uncertainty of 4 × 10 -10 . The unveiled emission LW (400 kHz at 1-ms integration time) indicates that DFG-QCLs are well suited to operate as local oscillators and to be used for a variety of metrological, spectroscopic, communication, and imaging applications that require narrow-LW THz sources.

Source identification and apportionment of heavy metals in urban soil profiles.

PubMed

Luo, Xiao-San; Xue, Yan; Wang, Yan-Ling; Cang, Long; Xu, Bo; Ding, Jing

2015-05-01

Because heavy metals (HMs) occurring naturally in soils accumulate continuously due to human activities, identifying and apportioning their sources becomes a challenging task for pollution prevention in urban environments. Besides the enrichment factors (EFs) and principal component analysis (PCA) for source classification, the receptor model (Absolute Principal Component Scores-Multiple Linear Regression, APCS-MLR) and Pb isotopic mixing model were also developed to quantify the source contribution for typical HMs (Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn) in urban park soils of Xiamen, a representative megacity in southeast China. Furthermore, distribution patterns of their concentrations and sources in 13 soil profiles (top 20 cm) were investigated by different depths (0-5, 5-10, 10-20 cm). Currently the principal anthropogenic source for HMs in urban soil of China is atmospheric deposition from coal combustion rather than vehicle exhaust. Specifically for Pb source by isotopic model ((206)Pb/(207)Pb and (208)Pb/(207)Pb), the average contributions were natural (49%)>coal combustion (45%)≫traffic emissions (6%). Although the urban surface soils are usually more contaminated owing to recent and current human sources, leaching effects and historic vehicle emissions can also make deep soil layer contaminated by HMs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of basal and induced cytochromes P450 in 6 species of waterfowl

USGS Publications Warehouse

Melancon, M.J.; Rattner, B.A.; Hoffman, D.J.; Beeman, D.; Day, D.; Custer, T.

1999-01-01

Cytochrome P450-associated monooxygenase activities were measured in control and prototype inducer-treated mallard duck, black duck, wood duck, lesser scaup, Canada goose and mute swan. Ages of the birds ranged from pipping embryos (that were treated approximately 3 days before pipping) to adults. Three or more of the following hepatic microsomal monooxygenases were assayed in each species: Benzyloxyresorufin-O-dealkylase (BROD), Ethoxyresorufin-O-dealkylase (EROD), methoxyresorufin-O-dealkylase (MROD), and pentoxyresorufin-O-dealkylase (PROD). Baseline activities differed between species, but because of differences in ages, sources of the eggs or birds, and diets, these cannot be viewed as absolute differences. The cytochrome P450 inducers utilized were beta-naphthoflavone (BNF), 3-methylcholanthrene (3MC) and phenobarbital (PB). In general, there was little response to PB; only lesser scaup were induced to greater than three times control level and most species were well under this. Responses to BNF and 3MC occurred in each species studied, but differed in which of the monooxygenases was most induced (absolute values and ratios to control values) and in relative induction between species. BROD frequently had an induction ratio EROD. Overall, lesser scaup were the most responsive, canada geese the least responsive, and the other species intermediate in responsiveness to the cytochrome P450 inducers studied.

A method for in situ absolute DD yield calibration of neutron time-of-flight detectors on OMEGA using CR-39-based proton detectors.

PubMed

Waugh, C J; Rosenberg, M J; Zylstra, A B; Frenje, J A; Séguin, F H; Petrasso, R D; Glebov, V Yu; Sangster, T C; Stoeckl, C

2015-05-01

Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition, comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.

A method for in situ absolute DD yield calibration of neutron time-of-flight detectors on OMEGA using CR-39-based proton detectors

DOE PAGES

Waugh, C. J.; Rosenberg, M. J.; Zylstra, A. B.; ...

2015-05-27

Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition,more » comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.« less

A method for in situ absolute DD yield calibration of neutron time-of-flight detectors on OMEGA using CR-39-based proton detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waugh, C. J.; Rosenberg, M. J.; Zylstra, A. B.

Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition,more » comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.« less

A method for in situ absolute DD yield calibration of neutron time-of-flight detectors on OMEGA using CR-39-based proton detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waugh, C. J., E-mail: cjwaugh@mit.edu; Zylstra, A. B.; Frenje, J. A.

2015-05-15

Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition,more » comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.« less

Debiased estimates for NEO orbits, absolute magnitudes, and source regions

NASA Astrophysics Data System (ADS)

Granvik, Mikael; Morbidelli, Alessandro; Jedicke, Robert; Bolin, Bryce T.; Bottke, William; Beshore, Edward C.; Vokrouhlicky, David; Nesvorny, David; Michel, Patrick

2017-10-01

The debiased absolute-magnitude and orbit distributions as well as source regions for near-Earth objects (NEOs) provide a fundamental frame of reference for studies on individual NEOs as well as on more complex population-level questions. We present a new four-dimensional model of the NEO population that describes debiased steady-state distributions of semimajor axis (a), eccentricity (e), inclination (i), and absolute magnitude (H). We calibrate the model using NEO detections by the 703 and G96 stations of the Catalina Sky Survey (CSS) during 2005-2012 corresponding to objects with 17

A frequency-stabilized light source at 399 nm using an Yb hollow-cathode lamp

NASA Astrophysics Data System (ADS)

Tanabe, Takehiko; Akamatsu, Daisuke; Inaba, Hajime; Okubo, Sho; Kobayashi, Takumi; Yasuda, Masami; Hosaka, Kazumoto; Hong, Feng-Lei

2018-06-01

We demonstrate a diode laser system operating at 399 nm that is stabilized to the 6s2 1S0–6s6p 1P1 electric dipole transition in ytterbium (Yb) atoms in a hollow-cathode lamp. The frequency stability of the laser reached 1.1 × 10‑11 at an averaging time of τ = 1 s. We performed an absolute frequency measurement using an optical frequency comb and determined that the absolute frequency of the laser stabilized to the 1S0–1P1 transition in 174Yb was 751 526 522.26(9) MHz. We also investigated several systematic frequency shifts while changing some of the light source parameters and measured several isotope shifts. The measured laser frequency will provide useful information regarding the practical use of the frequency-stabilized light source at 399 nm.

Neutron skyshine from intense 14-MeV neutron source facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, T.; Hayashi, K.; Takahashi, A.

1985-07-01

The dose distribution and the spectrum variation of neutrons due to the skyshine effect have been measured with the high-efficiency rem counter, the multisphere spectrometer, and the NE-213 scintillator in the environment surrounding an intense 14-MeV neutron source facility. The dose distribution and the energy spectra of neutrons around the facility used as a skyshine source have also been measured to enable the absolute evaluation of the skyshine effect. The skyshine effect was analyzed by two multigroup Monte Carlo codes, NIMSAC and MMCR-2, by two discrete ordinates S /sub n/ codes, ANISN and DOT3.5, and by the shield structure designmore » code for skyshine, SKYSHINE-II. The calculated results show good agreement with the measured results in absolute values. These experimental results should be useful as benchmark data for shyshine analysis and for shielding design of fusion facilities.« less

Calibration Against the Moon. I: A Disk-Resolved Lunar Model for Absolute Reflectance Calibration

DTIC Science & Technology

2010-01-01

average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and...3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Calibration against the Moon I: A disk- resolved lunar model for absolute reflectance...of the disk- resolved Moon at visible to near infrared wavelengths. It has been developed in order to use the Moon as a calibration reference

EEG activity during estral cycle in the rat.

PubMed

Corsi-Cabrera, M; Juárez, J; Ponce-de-León, M; Ramos, J; Velázquez, P N

1992-10-01

EEG activity was recorded from right and left parietal cortex in adult female rats daily during 6 days. Immediately after EEG recording vaginal smears were taken and were microscopically analyzed to determine the estral stage. Absolute and relative powers and interhemispheric correlation of EEG activity were calculated and compared between estral stages. Interhemispheric correlation was significantly lower during diestrous as compared to proestrous and estrous. Absolute and relative powers did not show significant differences between estral stages. Absolute powers of alpha1, alpha2, beta1 and beta2 bands were significantly higher at the right parietal cortex. Comparisons of the same EEG records with estral stages randomly grouped showed no significant differences for any of the EEG parameters. EEG activity is a sensitive tool to study functional changes related to the estral cycle.

Detection efficiency calculation for photons, electrons and positrons in a well detector. Part I: Analytical model

NASA Astrophysics Data System (ADS)

Pommé, S.

2009-06-01

An analytical model is presented to calculate the total detection efficiency of a well-type radiation detector for photons, electrons and positrons emitted from a radioactive source at an arbitrary position inside the well. The model is well suited to treat a typical set-up with a point source or cylindrical source and vial inside a NaI well detector, with or without lead shield surrounding it. It allows for fast absolute or relative total efficiency calibrations for a wide variety of geometrical configurations and also provides accurate input for the calculation of coincidence summing effects. Depending on its accuracy, it may even be applied in 4π-γ counting, a primary standardisation method for activity. Besides an accurate account of photon interactions, precautions are taken to simulate the special case of 511 keV annihilation quanta and to include realistic approximations for the range of (conversion) electrons and β -- and β +-particles.

A measurement of the absolute neutron beam polarization produced by an optically pumped 3He neutron spin filter

NASA Astrophysics Data System (ADS)

Rich, D. R.; Bowman, J. D.; Crawford, B. E.; Delheij, P. P. J.; Espy, M. A.; Haseyama, T.; Jones, G.; Keith, C. D.; Knudson, J.; Leuschner, M. B.; Masaike, A.; Masuda, Y.; Matsuda, Y.; Penttilä, S. I.; Pomeroy, V. R.; Smith, D. A.; Snow, W. M.; Szymanski, J. J.; Stephenson, S. L.; Thompson, A. K.; Yuan, V.

2002-04-01

The capability of performing accurate absolute measurements of neutron beam polarization opens a number of exciting opportunities in fundamental neutron physics and in neutron scattering. At the LANSCE pulsed neutron source we have measured the neutron beam polarization with an absolute accuracy of 0.3% in the neutron energy range from 40 meV to 10 eV using an optically pumped polarized 3He spin filter and a relative transmission measurement technique. 3He was polarized using the Rb spin-exchange method. We describe the measurement technique, present our results, and discuss some of the systematic effects associated with the method.

A vibration-insensitive optical cavity and absolute determination of its ultrahigh stability.

PubMed

Zhao, Y N; Zhang, J; Stejskal, A; Liu, T; Elman, V; Lu, Z H; Wang, L J

2009-05-25

We use the three-cornered-hat method to evaluate the absolute frequency stabilities of three different ultrastable reference cavities, one of which has a vibration-insensitive design that does not even require vibration isolation. An Nd:YAG laser and a diode laser are implemented as light sources. We observe approximately 1 Hz beat note linewidths between all three cavities. The measurement demonstrates that the vibration-insensitive cavity has a good frequency stability over the entire measurement time from 100 ms to 200 s. An absolute, correlation-removed Allan deviation of 1.4 x 10(-15) at s of this cavity is obtained, giving a frequency uncertainty of only 0.44 Hz.

Absolute versus relative intensity of physical activity in a dose-response context.

PubMed

Shephard, R J

2001-06-01

To examine the importance of relative versus absolute intensities of physical activity in the context of population health. A standard computer-search of the literature was supplemented by review of extensive personal files. Consensus reports (Category D Evidence) have commonly recommended moderate rather than hard physical activity in the context of population health. Much of the available literature provides Category C Evidence. It has often confounded issues of relative intensity with absolute intensity or total weekly dose of exercise. In terms of cardiovascular health, there is some evidence for a threshold intensity of effort, perhaps as high as 6 METs, in addition to a minimum volume of physical activity. Decreases in blood pressure and prevention of stroke seem best achieved by moderate rather than high relative intensities of physical activity. Many aspects of metabolic health depend on the total volume of activity; moderate relative intensities of effort are more effective in mobilizing body fat, but harder relative intensities may help to increase energy expenditures postexercise. Hard relative intensities seem needed to augment bone density, but this may reflect an associated increase in volume of activity. Hard relative intensities of exercise induce a transient immunosuppression. The optimal intensity of effort, relative or absolute, for protection against various types of cancer remains unresolved. Acute effects of exercise on mood state also require further study; long-term benefits seem associated with a moderate rather than a hard relative intensity of effort. The importance of relative versus absolute intensity of effort depends on the desired health outcome, and many issues remain to be resolved. Progress will depend on more precise epidemiological methods of assessing energy expenditures and studies that equate total energy expenditures between differing relative intensities. There is a need to focus on gains in quality-adjusted life expectancy.

Performance of Different Light Sources for the Absolute Calibration of Radiation Thermometers

NASA Astrophysics Data System (ADS)

Martín, M. J.; Mantilla, J. M.; del Campo, D.; Hernanz, M. L.; Pons, A.; Campos, J.

2017-09-01

The evolving mise en pratique for the definition of the kelvin (MeP-K) [1, 2] will, in its forthcoming edition, encourage the realization and dissemination of the thermodynamic temperature either directly (primary thermometry) or indirectly (relative primary thermometry) via fixed points with assigned reference thermodynamic temperatures. In the last years, the Centro Español de Metrología (CEM), in collaboration with the Instituto de Óptica of Consejo Superior de Investigaciones Científicas (IO-CSIC), has developed several setups for absolute calibration of standard radiation thermometers using the radiance method to allow CEM the direct dissemination of the thermodynamic temperature and the assignment of the thermodynamic temperatures to several fixed points. Different calibration facilities based on a monochromator and/or a laser and an integrating sphere have been developed to calibrate CEM's standard radiation thermometers (KE-LP2 and KE-LP4) and filter radiometer (FIRA2). This system is based on the one described in [3] placed in IO-CSIC. Different light sources have been tried and tested for measuring absolute spectral radiance responsivity: a Xe-Hg 500 W lamp, a supercontinuum laser NKT SuperK-EXR20 and a diode laser emitting at 6473 nm with a typical maximum power of 120 mW. Their advantages and disadvantages have been studied such as sensitivity to interferences generated by the laser inside the filter, flux stability generated by the radiant sources and so forth. This paper describes the setups used, the uncertainty budgets and the results obtained for the absolute temperatures of Cu, Co-C, Pt-C and Re-C fixed points, measured with the three thermometers with central wavelengths around 650 nm.

The influence of maturation, body size and physical self-perceptions on longitudinal changes in physical activity in adolescent girls.

PubMed

Fawkner, Samantha; Henretty, Joan; Knowles, Ann-Marie; Nevill, Alan; Niven, Ailsa

2014-01-01

The aim of this study was to adopt a longitudinal design to explore the direct effects of both absolute and relative maturation and changes in body size on physical activity, and explore if, and how, physical self-perceptions might mediate this effect. We recruited 208 girls (11.8 ± 0.4 years) at baseline. Data were collected at three subsequent time points, each 6 months apart. At 18 months, 119 girls remained in the study. At each time point, girls completed the Physical Activity Questionnaire for Children, the Pubertal Development Scale (from which, both a measure of relative and absolute maturation were defined) and the Physical Self-Perception Profile, and had physical size characteristics assessed. Multilevel modelling for physical activity indicated a significant negative effect of age, positive effect for physical condition and sport competence and positive association for relatively early maturers. Absolute maturation, body mass, waist circumference and sum of skinfolds did not significantly contribute to the model. Contrary to common hypotheses, relatively more mature girls may, in fact, be more active than their less mature peers. However, neither changes in absolute maturation nor physical size appear to directly influence changes in physical activity in adolescent girls.

Method and apparatus for making absolute range measurements

DOEpatents

Earl, Dennis D [Knoxville, TN; Allison, Stephen W [Knoxville, TN; Cates, Michael R [Oak Ridge, TN; Sanders, Alvin J [Knoxville, TN

2002-09-24

This invention relates to a method and apparatus for making absolute distance or ranging measurements using Fresnel diffraction. The invention employs a source of electromagnetic radiation having a known wavelength or wavelength distribution, which sends a beam of electromagnetic radiation through a screen at least partially opaque at the wavelength. The screen has an aperture sized so as to produce a Fresnel diffraction pattern. A portion of the beam travels through the aperture to a detector spaced some distance from the screen. The detector detects the central intensity of the beam as well as a set of intensities displaced from a center of the aperture. The distance from the source to the target can then be calculated based upon the known wavelength, aperture radius, and beam intensity.

Measurements of the properties of solar wind plasma relevant to studies of its coronal sources

NASA Technical Reports Server (NTRS)

Neugebauer, M.

1982-01-01

Interplanetary measurements of the speeds, densities, abundances, and charge states of solar wind ions are diagnostic of conditions in the source region of the solar wind. The absolute values of the mass, momentum, and energy fluxes in the solar wind are not known to an accuracy of 20%. The principal limitations on the absolute accuracies of observations of solar wind protons and alpha particles arise from uncertain instrument calibrations, from the methods used to reduce the data, and from sampling biases. Sampling biases are very important in studies of alpha particles. Instrumental resolution and measurement ambiguities are additional major problems for the observation of ions heavier than helium. Progress in overcoming some of these measurement inadequacies is reviewed.

Artifact correction and absolute radiometric calibration techniques employed in the Landsat 7 image assessment system

USGS Publications Warehouse

Boncyk, Wayne C.; Markham, Brian L.; Barker, John L.; Helder, Dennis

1996-01-01

The Landsat-7 Image Assessment System (IAS), part of the Landsat-7 Ground System, will calibrate and evaluate the radiometric and geometric performance of the Enhanced Thematic Mapper Plus (ETM +) instrument. The IAS incorporates new instrument radiometric artifact correction and absolute radiometric calibration techniques which overcome some limitations to calibration accuracy inherent in historical calibration methods. Knowledge of ETM + instrument characteristics gleaned from analysis of archival Thematic Mapper in-flight data and from ETM + prelaunch tests allow the determination and quantification of the sources of instrument artifacts. This a priori knowledge will be utilized in IAS algorithms designed to minimize the effects of the noise sources before calibration, in both ETM + image and calibration data.

Mapping hemispheric symmetries, relative asymmetries, and absolute asymmetries underlying the auditory laterality effect.

PubMed

Westerhausen, René; Kompus, Kristiina; Hugdahl, Kenneth

2014-01-01

Functional hemispheric differences for speech and language processing have been traditionally studied by using verbal dichotic-listening paradigms. The commonly observed right-ear preference for the report of dichotically presented syllables is taken to reflect the left hemispheric dominance for speech processing. However, the results of recent functional imaging studies also show that both hemispheres - not only the left - are engaged by dichotic listening, suggesting a more complex relationship between behavioral laterality and functional hemispheric activation asymmetries. In order to more closely examine the hemispheric differences underlying dichotic-listening performance, we report an analysis of functional magnetic resonance imaging (fMRI) data of 104 right-handed subjects, for the first time combining an interhemispheric difference and conjunction analysis. This approach allowed for a distinction of homotopic brain regions which showed symmetrical (i.e., brain region significantly activated in both hemispheres and no activation difference between the hemispheres), relative asymmetrical (i.e., activated in both hemispheres but significantly stronger in one than the other hemisphere), and absolute asymmetrical activation patterns (i.e., activated only in one hemisphere and this activation is significantly stronger than in the other hemisphere). Symmetrical activation was found in large clusters encompassing temporal, parietal, inferior frontal, and medial superior frontal regions. Relative and absolute left-ward asymmetries were found in the posterior superior temporal gyrus, located adjacent to symmetrically activated areas, and creating a lateral-medial gradient from symmetrical towards absolute asymmetrical activation within the peri-Sylvian region. Absolute leftward asymmetry was also found in the post-central and medial superior frontal gyri, while rightward asymmetries were found in middle temporal and middle frontal gyri. We conclude that dichotic listening engages a bihemispheric cortical network, showing a symmetrical and mostly leftward asymmetrical pattern. The here obtained functional (a)symmetry map might serve as a basis for future studies which - by studying the relevance of the here identified regions - clarify the relationship between behavioral laterality measures and hemispheric asymmetry. © 2013 Elsevier Inc. All rights reserved.

Simulated cosmic microwave background maps at 0.5 deg resolution: Unresolved features

NASA Technical Reports Server (NTRS)

Kogut, A.; Hinshaw, G.; Bennett, C. L.

1995-01-01

High-contrast peaks in the cosmic microwave background (CMB) anisotropy can appear as unresolved sources to observers. We fit simluated CMB maps generated with a cold dark matter model to a set of unresolved features at instrumental resolution 0.5 deg-1.5 deg to derive the integral number density per steradian n (greater than absolute value of T) of features brighter than threshold temperature absolute value of T and compare the results to recent experiments. A typical medium-scale experiment observing 0.001 sr at 0.5 deg resolution would expect to observe one feature brighter than 85 micro-K after convolution with the beam profile, with less than 5% probability to observe a source brighter than 150 micro-K. Increasing the power-law index of primordial density perturbations n from 1 to 1.5 raises these temperature limits absolute value of T by a factor of 2. The MSAM features are in agreement with standard cold dark matter models and are not necessarily evidence for processes beyond the standard model.

Ethanol used as an environmentally sustainable energy resource for thermal power plants

NASA Astrophysics Data System (ADS)

Markov, V. A.; Biryukov, V. V.; Kas'kov, S. I.

2016-09-01

Justification of using renewable energy sources and a brief analysis of their application prospects is given. The most common renewable energy sources for mobile thermal power plants are presented. The possibilities and ways of using ethanol as an energy source for such plants with diesel engines are analyzed. It is shown that it is feasible to add small amounts of ethanol to oil diesel fuel (DF) for obtaining an environmentally sustainable energy source for diesel engines. Therewith, a stable mixture of components can be obtained by adding anhydrous (absolute) ethanol to the oil fuel. The authors studied a mixture containing 4% (by volume) of absolute ethanol and 96% of oil DF. The physicochemical properties of the mixture and each of its components are presented. Diesel engine of the type D-245.12S has been experimentally studied using the mixture of DF and ethanol. The possibility of reducing the toxicity level of the exhaust emissions when using this mixture as an energy source for diesel engines of mobile power plants is shown. Transition of the studied diesel engine from oil DF to its mixture with ethanol made it possible to reduce the smoke capacity of the exhaust gases by 15-25% and to decrease the specific mass emissions of nitrogen oxides by 17.4%. In this case, we observed a slight increase in the exhaust gas emissions of carbon monoxide and light unburned hydrocarbons, which, however, can easily be eliminated by providing the exhaust system of a diesel engine with a catalytic converter. It is noted that the studied mixture composition should be optimized. The conclusion is made that absolute ethanol is a promising ecofriendly additive to oil diesel fuel and should be used in domestic diesel engines.

Design of high pressure oxygen filter for extravehicular activity life support system, volume 1

NASA Technical Reports Server (NTRS)

Wilson, B. A.

1977-01-01

The experience of the National Aeronautics and Space Administration (NASA) with extravehicular activity life support emergency oxygen supply subsystems has shown a large number of problems associated with particulate contamination. These problems have resulted in failures of high pressure oxygen component sealing surfaces. A high pressure oxygen filter was designed which would (a) control the particulate contamination level in the oxygen system to a five-micron glass bead rating, ten-micron absolute condition (b) withstand the dynamic shock condition resulting from the sudden opening of 8000 psi oxygen system shutoff valve. Results of the following program tasks are reported: (1) contaminant source identification tests, (2) dynamic system tests, (3) high pressure oxygen filter concept evaluation, (4) design, (5) fabrication, (6) test, and (7) application demonstration.

The relationship between poverty and fertility in some less developed countries.

PubMed

Chin Ptc

1985-12-01

The author investigates the extent to which both absolute and relative poverty affect population growth in developing countries. Aggregate data from U.N. sources for 26 countries at various stages of the fertility transition are used. The results indicate that the most significant steps in reducing fertility would be more effective provision of basic human needs and reforms in land tenure. The need to distinguish between absolute and relative poverty in formulating population policies is noted.

Mosher Amides: Determining the Absolute Stereochemistry of Optically-Active Amines

ERIC Educational Resources Information Center

Allen, Damian A.; Tomaso, Anthony E., Jr.; Priest, Owen P.; Hindson, David F.; Hurlburt, Jamie L.

2008-01-01

The use of chiral reagents for the derivatization of optically-active amines and alcohols for the purpose of determining their enantiomeric purity or absolute configuration is a tool used by many chemists. Among the techniques used, Mosher's amide and Mosher's ester analyses are among the most reliable and one of the most often used. Despite this,…

SU-E-T-68: A Quality Assurance System with a Web Camera for High Dose Rate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueda, Y; Hirose, A; Oohira, S

Purpose: The purpose of this work was to develop a quality assurance (QA) system for high dose rate (HDR) brachytherapy to verify the absolute position of an 192Ir source in real time and to measure dwell time and position of the source simultaneously with a movie recorded by a web camera. Methods: A web camera was fixed 15 cm above a source position check ruler to monitor and record 30 samples of the source position per second over a range of 8.0 cm, from 1425 mm to 1505 mm. Each frame had a matrix size of 480×640 in the movie.more » The source position was automatically quantified from the movie using in-house software (built with LabVIEW) that applied a template-matching technique. The source edge detected by the software on each frame was corrected to reduce position errors induced by incident light from an oblique direction. The dwell time was calculated by differential processing to displacement of the source. The performance of this QA system was illustrated by recording simple plans and comparing the measured dwell positions and time with the planned parameters. Results: This QA system allowed verification of the absolute position of the source in real time. The mean difference between automatic and manual detection of the source edge was 0.04 ± 0.04 mm. Absolute position error can be determined within an accuracy of 1.0 mm at dwell points of 1430, 1440, 1450, 1460, 1470, 1480, 1490, and 1500 mm, in three step sizes and dwell time errors, with an accuracy of 0.1% in more than 10.0 sec of planned time. The mean step size error was 0.1 ± 0.1 mm for a step size of 10.0 mm. Conclusion: This QA system provides quick verifications of the dwell position and time, with high accuracy, for HDR brachytherapy. This work was supported by the Japan Society for the Promotion of Science Core-to-Core program (No. 23003)« less

Information Foraging for Perceptual Decisions

PubMed Central

2016-01-01

We tested an information foraging framework to characterize the mechanisms that drive active (visual) sampling behavior in decision problems that involve multiple sources of information. Experiments 1 through 3 involved participants making an absolute judgment about the direction of motion of a single random dot motion pattern. In Experiment 4, participants made a relative comparison between 2 motion patterns that could only be sampled sequentially. Our results show that: (a) Information (about noisy motion information) grows to an asymptotic level that depends on the quality of the information source; (b) The limited growth is attributable to unequal weighting of the incoming sensory evidence, with early samples being weighted more heavily; (c) Little information is lost once a new source of information is being sampled; and (d) The point at which the observer switches from 1 source to another is governed by online monitoring of his or her degree of (un)certainty about the sampled source. These findings demonstrate that the sampling strategy in perceptual decision-making is under some direct control by ongoing cognitive processing. More specifically, participants are able to track a measure of (un)certainty and use this information to guide their sampling behavior. PMID:27819455

A comparison study on various low energy sources in interstitial prostate brachytherapy

PubMed Central

Bakhshabadi, Mahdi; Ghorbani, Mahdi; Knaup, Courtney; Meigooni, Ali S.

2016-01-01

Purpose Low energy sources are routinely used in prostate brachytherapy. 125I is one of the most commonly used sources. Low energy 131Cs source was introduced recently as a brachytherapy source. The aim of this study is to compare dose distributions of 125I, 103Pd, and 131Cs sources in interstitial brachytherapy of prostate. Material and methods ProstaSeed 125I brachytherapy source was simulated using MCNPX Monte Carlo code. Additionally, two hypothetical sources of 103Pd and 131Cs were simulated with the same geometry as the ProstaSeed 125I source, while having their specific emitted gamma spectra. These brachytherapy sources were simulated with distribution of forty-eight seeds in a phantom including prostate. The prostate was considered as a sphere with radius of 1.5 cm. Absolute and relative dose rates were obtained in various distances from the source along the transverse and longitudinal axes inside and outside the tumor. Furthermore, isodose curves were plotted around the sources. Results Analyzing the initial dose profiles for various sources indicated that with the same time duration and air kerma strength, 131Cs delivers higher dose to tumor. However, relative dose rate inside the tumor is higher and outside the tumor is lower for the 103Pd source. Conclusions The higher initial absolute dose in cGy/(h.U) of 131Cs brachytherapy source is an advantage of this source over the others. The higher relative dose inside the tumor and lower relative dose outside the tumor for the 103Pd source are advantages of this later brachytherapy source. Based on the total dose the 125I source has advantage over the others due to its longer half-life. PMID:26985200

A comparison study on various low energy sources in interstitial prostate brachytherapy.

PubMed

Bakhshabadi, Mahdi; Ghorbani, Mahdi; Khosroabadi, Mohsen; Knaup, Courtney; Meigooni, Ali S

2016-02-01

Low energy sources are routinely used in prostate brachytherapy. (125)I is one of the most commonly used sources. Low energy (131)Cs source was introduced recently as a brachytherapy source. The aim of this study is to compare dose distributions of (125)I, (103)Pd, and (131)Cs sources in interstitial brachytherapy of prostate. ProstaSeed (125)I brachytherapy source was simulated using MCNPX Monte Carlo code. Additionally, two hypothetical sources of (103)Pd and (131)Cs were simulated with the same geometry as the ProstaSeed (125)I source, while having their specific emitted gamma spectra. These brachytherapy sources were simulated with distribution of forty-eight seeds in a phantom including prostate. The prostate was considered as a sphere with radius of 1.5 cm. Absolute and relative dose rates were obtained in various distances from the source along the transverse and longitudinal axes inside and outside the tumor. Furthermore, isodose curves were plotted around the sources. Analyzing the initial dose profiles for various sources indicated that with the same time duration and air kerma strength, (131)Cs delivers higher dose to tumor. However, relative dose rate inside the tumor is higher and outside the tumor is lower for the (103)Pd source. The higher initial absolute dose in cGy/(h.U) of (131)Cs brachytherapy source is an advantage of this source over the others. The higher relative dose inside the tumor and lower relative dose outside the tumor for the (103)Pd source are advantages of this later brachytherapy source. Based on the total dose the (125)I source has advantage over the others due to its longer half-life.

Error Analysis of non-TLD HDR Brachytherapy Dosimetric Techniques

NASA Astrophysics Data System (ADS)

Amoush, Ahmad

The American Association of Physicists in Medicine Task Group Report43 (AAPM-TG43) and its updated version TG-43U1 rely on the LiF TLD detector to determine the experimental absolute dose rate for brachytherapy. The recommended uncertainty estimates associated with TLD experimental dosimetry include 5% for statistical errors (Type A) and 7% for systematic errors (Type B). TG-43U1 protocol does not include recommendation for other experimental dosimetric techniques to calculate the absolute dose for brachytherapy. This research used two independent experimental methods and Monte Carlo simulations to investigate and analyze uncertainties and errors associated with absolute dosimetry of HDR brachytherapy for a Tandem applicator. An A16 MicroChamber* and one dose MOSFET detectors† were selected to meet the TG-43U1 recommendations for experimental dosimetry. Statistical and systematic uncertainty analyses associated with each experimental technique were analyzed quantitatively using MCNPX 2.6‡ to evaluate source positional error, Tandem positional error, the source spectrum, phantom size effect, reproducibility, temperature and pressure effects, volume averaging, stem and wall effects, and Tandem effect. Absolute dose calculations for clinical use are based on Treatment Planning System (TPS) with no corrections for the above uncertainties. Absolute dose and uncertainties along the transverse plane were predicted for the A16 microchamber. The generated overall uncertainties are 22%, 17%, 15%, 15%, 16%, 17%, and 19% at 1cm, 2cm, 3cm, 4cm, and 5cm, respectively. Predicting the dose beyond 5cm is complicated due to low signal-to-noise ratio, cable effect, and stem effect for the A16 microchamber. Since dose beyond 5cm adds no clinical information, it has been ignored in this study. The absolute dose was predicted for the MOSFET detector from 1cm to 7cm along the transverse plane. The generated overall uncertainties are 23%, 11%, 8%, 7%, 7%, 9%, and 8% at 1cm, 2cm, 3cm, and 4cm, 5cm, 6cm, and 7cm, respectively. The Nucletron Freiburg flap applicator is used with the Nucletron remote afterloader HDR machine to deliver dose to surface cancers. Dosimetric data for the Nucletron 192Ir source were generated using Monte Carlo simulation and compared with the published data. Two dimensional dosimetric data were calculated at two source positions; at the center of the sphere of the applicator and between two adjacent spheres. Unlike the TPS dose algorithm, The Monte Carlo code developed for this research accounts for the applicator material, secondary electrons and delta particles, and the air gap between the skin and the applicator. *Standard Imaging, Inc., Middleton, Wisconsin USA † OneDose MOSFET, Sicel Technologies, Morrisville NC ‡ Los Alamos National Laboratory, NM USA

Radio polarization properties of quasars and active galaxies at high redshifts

NASA Astrophysics Data System (ADS)

Vernstrom, T.; Gaensler, B. M.; Vacca, V.; Farnes, J. S.; Haverkorn, M.; O'Sullivan, S. P.

2018-04-01

We present the largest ever sample of radio polarization properties for z > 4 sources, with 14 sources having significant polarization detections. Using wide-band data from the Karl G. Jansky Very Large Array, we obtained the rest-frame total intensity and polarization properties of 37 radio sources, nine of which have spectroscopic redshifts in the range 1 ≤ z ≤ 1.4, with the other 28 having spectroscopic redshifts in the range 3.5 ≤ z ≤ 6.21. Fits are performed for the Stokes I and fractional polarization spectra, and Faraday rotation measures are derived using rotation measure synthesis and QU fitting. Using archival data of 476 polarized sources, we compare high-redshift (z > 3) source properties to a 15 GHz rest-frame luminosity matched sample of low-redshift (z < 3) sources to investigate if the polarization properties of radio sources at high redshifts are intrinsically different than those at low redshift. We find a mean of the rotation measure absolute values, corrected for Galactic rotation, of 50 ± 22 rad m-2 for z > 3 sources and 57 ± 4 rad m-2 for z < 3. Although there is some indication of lower intrinsic rotation measures at high-z possibly due to higher depolarization from the high-density environments, using several statistical tests we detect no significant difference between low- and high-redshift sources. Larger samples are necessary to determine any true physical difference.

Accumulation degree and source apportionment of trace metals in smaller than 63 μm road dust from the areas with different land uses: A case study of Xi'an, China.

PubMed

Shi, Dongqi; Lu, Xinwei

2018-09-15

Finer urban dusts have more serious environmental detriment and health risk than coarser urban dusts. The trace metals Pb, Cu, Zn, Cr, Co, Ba, Mn, Ni, V, Y, Rb, Ga, Hf, and Zr were analyzed using X-ray fluorescence spectrometry in smaller than 63 μm road dust collected from the areas with different land use types and human activities in Xi'an city. The purposes of this study were to reveal the impact of human activities on the environment through element enrichment factor, and to determine the sources of trace metals measured by multivariate statistical analysis and multiple liner regression of absolute principal component scores. The results indicated that the smaller than 63 μm road dust in Xi'an, in comparison to the element background value of local soil, had higher Cu, Pb, Zn, Cr, Y, Hf and Zr concentrations. Trace metals had different variations in the dusts, while the anthropogenic trace metals had no significant difference in the four areas owing to the wide existing of human activities. The accumulation level of Pb was the highest, followed by Cr, Cu and Zn, and then was Hf and Zr, while the other trace metals were deficient or deficient to minimal enrichment in the finer road dust. Source analysis results indicated that Co, Ga, Mn, Ni, V, Rb and Y mainly originated from natural source, which accounted about 57%-87% for these metals' concentration. Ba, Cr, Pb, Cu and Zn primarily derived from traffic source, which contributed approximately 59%-79% to these metals' content. Hf and Zr were mainly from construction source, which contributed 74.6% to Hf concentration and 78.2% to Zr concentration. The study indicated that traffic and construction activities had a predominant influence on local environment. Copyright © 2018 Elsevier B.V. All rights reserved.

Water Quality Assessment of River Soan (Pakistan) and Source Apportionment of Pollution Sources Through Receptor Modeling.

PubMed

Nazeer, Summya; Ali, Zeshan; Malik, Riffat Naseem

2016-07-01

The present study was designed to determine the spatiotemporal patterns in water quality of River Soan using multivariate statistics. A total of 26 sites were surveyed along River Soan and its associated tributaries during pre- and post-monsoon seasons in 2008. Hierarchical agglomerative cluster analysis (HACA) classified sampling sites into three groups according to their degree of pollution, which ranged from least to high degradation of water quality. Discriminant function analysis (DFA) revealed that alkalinity, orthophosphates, nitrates, ammonia, salinity, and Cd were variables that significantly discriminate among three groups identified by HACA. Temporal trends as identified through DFA revealed that COD, DO, pH, Cu, Cd, and Cr could be attributed for major seasonal variations in water quality. PCA/FA identified six factors as potential sources of pollution of River Soan. Absolute principal component scores using multiple regression method (APCS-MLR) further explained the percent contribution from each source. Heavy metals were largely added through industrial activities (28 %) and sewage waste (28 %), nutrients through agriculture runoff (35 %) and sewage waste (28 %), organic pollution through sewage waste (27 %) and urban runoff (17 %) and macroelements through urban runoff (39 %), and mineralization and sewage waste (30 %). The present study showed that anthropogenic activities are the major source of variations in River Soan. In order to address the water quality issues, implementation of effective waste management measures are needed.

Spectral purity and tunability of terahertz quantum cascade laser sources based on intracavity difference-frequency generation

PubMed Central

Consolino, Luigi; Jung, Seungyong; Campa, Annamaria; De Regis, Michele; Pal, Shovon; Kim, Jae Hyun; Fujita, Kazuue; Ito, Akio; Hitaka, Masahiro; Bartalini, Saverio; De Natale, Paolo; Belkin, Mikhail A.; Vitiello, Miriam Serena

2017-01-01

Terahertz sources based on intracavity difference-frequency generation in mid-infrared quantum cascade lasers (THz DFG-QCLs) have recently emerged as the first monolithic electrically pumped semiconductor sources capable of operating at room temperature across the 1- to 6-THz range. Despite tremendous progress in power output, which now exceeds 1 mW in pulsed and 10 μW in continuous-wave regimes at room temperature, knowledge of the major figure of merits of these devices for high-precision spectroscopy, such as spectral purity and absolute frequency tunability, is still lacking. By exploiting a metrological grade system comprising a terahertz frequency comb synthesizer, we measure, for the first time, the free-running emission linewidth (LW), the tuning characteristics, and the absolute center frequency of individual emission lines of these sources with an uncertainty of 4 × 10−10. The unveiled emission LW (400 kHz at 1-ms integration time) indicates that DFG-QCLs are well suited to operate as local oscillators and to be used for a variety of metrological, spectroscopic, communication, and imaging applications that require narrow-LW THz sources. PMID:28879235

Approaches on calibration of bolometer and establishment of bolometer calibration device

NASA Astrophysics Data System (ADS)

Xia, Ming; Gao, Jianqiang; Ye, Jun'an; Xia, Junwen; Yin, Dejin; Li, Tiecheng; Zhang, Dong

2015-10-01

Bolometer is mainly used for measuring thermal radiation in the field of public places, labor hygiene, heating and ventilation and building energy conservation. The working principle of bolometer is under the exposure of thermal radiation, temperature of black absorbing layer of detector rise after absorption of thermal radiation, which makes the electromotive force produced by thermoelectric. The white light reflective layer of detector does not absorb thermal radiation, so the electromotive force produced by thermoelectric is almost zero. A comparison of electromotive force produced by thermoelectric of black absorbing layer and white reflective layer can eliminate the influence of electric potential produced by the basal background temperature change. After the electromotive force which produced by thermal radiation is processed by the signal processing unit, the indication displays through the indication display unit. The measurement unit of thermal radiation intensity is usually W/m2 or kW/m2. Its accurate and reliable value has important significance for high temperature operation, labor safety and hygiene grading management. Bolometer calibration device is mainly composed of absolute radiometer, the reference light source, electric measuring instrument. Absolute radiometer is a self-calibration type radiometer. Its working principle is using the electric power which can be accurately measured replaces radiation power to absolutely measure the radiation power. Absolute radiometer is the standard apparatus of laser low power standard device, the measurement traceability is guaranteed. Using the calibration method of comparison, the absolute radiometer and bolometer measure the reference light source in the same position alternately which can get correction factor of irradiance indication. This paper is mainly about the design and calibration method of the bolometer calibration device. The uncertainty of the calibration result is also evaluated.

Passive and active vibration isolation systems using inerter

NASA Astrophysics Data System (ADS)

Alujević, N.; Čakmak, D.; Wolf, H.; Jokić, M.

2018-03-01

This paper presents a theoretical study on passive and active vibration isolation schemes using inerter elements in a two degree of freedom (DOF) mechanical system. The aim of the work is to discuss basic capabilities and limitations of the vibration control systems at hand using simple and physically transparent models. Broad frequency band dynamic excitation of the source DOF is assumed. The purpose of the isolator system is to prevent vibration transmission to the receiving DOF. The frequency averaged kinetic energy of the receiving mass is used as the metric for vibration isolation quality. It is shown that the use of inerter element in the passive vibration isolation scheme can enhance the isolation effect. In the active case, a feedback disturbance rejection scheme is considered. Here, the error signal is the receiving body absolute velocity which is directly fed to a reactive force actuator between the source and the receiving bodies. In such a scheme, the so-called subcritical vibration isolation problems exist. These problems are characterised by the uncoupled natural frequency of the receiving body larger than the uncoupled natural frequency of the source body. In subcritical vibration isolation problems, the performance of the active control is limited by poor stability margins. This is because the stable feedback gain is restricted in a narrow range between a minimum and a maximum. However, with the inclusion of an inerter in the isolator, one of the two stability margins can be opened. This enables large, theoretically unlimited negative feedback gains and large active damping of the receiving body vibration. A simple expression for the required inertance is derived.

Conditional associative memory for musical stimuli in nonmusicians: implications for absolute pitch.

PubMed

Bermudez, Patrick; Zatorre, Robert J

2005-08-24

A previous positron emission tomography (PET) study of musicians with and without absolute pitch put forth the hypothesis that the posterior dorsolateral prefrontal cortex is involved in the conditional associative aspect of the identification of a pitch. In the work presented here, we tested this hypothesis by training eight nonmusicians to associate each of four different complex musical sounds (triad chords) with an arbitrary number in a task designed to have limited analogy to absolute-pitch identification. Each subject under-went a functional magnetic resonance imaging scanning procedure both before and after training. Active condition (identification of chords)-control condition (amplitude-matched noise bursts) comparisons for the pretraining scan showed no significant activation maxima. The same comparison for the posttraining scan revealed significant peaks of activation in posterior dorsolateral prefrontal, ventrolateral prefrontal, and parietal areas. A conjunction analysis was performed to show that the posterior dorsolateral prefrontal activity in this study is similar to that observed in the aforementioned PET study. We conclude that the posterior dorsolateral prefrontal cortex is selectively involved in the conditional association aspect of our task, as it is in the attribution of a verbal label to a note by absolute-pitch musicians.

Social care and support for elderly men and women in an urban and a rural area of Nepal.

PubMed

Kshetri, Dan Bahadur Baidwar; Smith, Cairns S; Khadka, Mira

2012-09-01

This study has aimed to describe the care and support for urban and rural elderly people of Bhaktapur district, Nepal. Efforts were made to identify the feeling of some features of general well-beings associated to mental health, person responsible for care and support, capability to perform daily routine activities, sources of finance and ownership to the property. More than half of the respondents were found having single or multiple features of loneliness, anxiety, depression and insomnia. The rate of point prevalence loneliness was found higher in the above 80 years of age, urban respondents. Almost 9 in 10 respondents were capable themselves to dress, walk and maintain personal hygiene and majority of them were assisted by spouse, son/daughter-in-laws. Family support was common sources of income and ownership to the property was absolutely high.

Anchoring historical sequences using a new source of astro-chronological tie-points

NASA Astrophysics Data System (ADS)

Dee, Michael W.; Pope, Benjamin J. S.

2016-08-01

The discovery of past spikes in atmospheric radiocarbon activity, caused by major solar energetic particle events, has opened up new possibilities for high-precision chronometry. The two spikes, or Miyake Events, have now been widely identified in tree-rings that grew in the years 775 and 994 CE. Furthermore, all other plant material that grew in these years would also have incorporated the anomalously high concentrations of radiocarbon. Crucially, some plant-based artefacts, such as papyrus documents, timber beams and linen garments, can also be allocated to specific positions within long, currently unfixed, historical sequences. Thus, Miyake Events represent a new source of tie-points that could provide the means for anchoring early chronologies to the absolute timescale. Here, we explore this possibility, outlining the most expeditious approaches, the current challenges and obstacles, and how they might best be overcome.

The population, magnitudes, and sizes of Jupiter family comets

NASA Astrophysics Data System (ADS)

Fernández, J. A.; Tancredi, G.; Rickman, H.; Licandro, J.

1999-12-01

We analyze the sample of measured nuclear magnitudes of the observed Jupiter family (JF) comets (taken as those with orbital periods P < 20 years and Tisserand parameters T > 2). We find a tendency of the measured nuclear magnitudes to be fainter as JF comets are observed with CCD detectors attached to medium- and large-size telescopes (e.g. Spacewatch Telescope). However, a few JF comets observed very far from the Sun (4-7 AU) show a wide dispersion of their derived absolute nuclear magnitudes which suggests that either these JF comets keep active all along the orbit, so the reported unusually bright distant magnitudes were strongly contaminated by a coma, or some of the measured ``nuclear magnitudes'' were grossly overestimated (i.e. their brightness underestimated). The cumulative mass distribution of JF comets is found to follow a power-law of index s = - 0.88 +/- 0.08, suggesting a distribution significantly steeper than that for both small main-belt asteroids and near-Earth asteroids. The cumulative mass distribution of JF comets with q < 2 AU tends to flatten for absolute (visual) nuclear magnitudes H_N > 16, which is probably due to incompleteness of discovery of fainter comets and/or a real scarcity of small comets due, perhaps, to much shorter physical lifetimes. In particular, no JF comets fainter than H_N ~ 19.5 are found in the sample, suggesting that the critical size for a comet to be still active may be of about 0.4 km radius for an assumed geometric albedo of 0.04. Possibly, smaller comet nuclei disintegrate very quickly into meteor streams. Most absolute nuclear magnitudes are found in the range 15-18, corresponding to nuclear radii in the range 0.8-3.3 km (for the same geometric albedo). We find that a large majority of JF comets with perihelion distances q > 2.5 AU are brighter than absolute nuclear magnitude H_N = 16, suggesting that only a very small fraction (a few percent) of the population of the JF comets with large q has so far been detected. A similar trend is noted for the corresponding absolute total magnitudes H_T taken from Kresák & Kresáková's (1994) catalog. By analyzing the H_N and H_T data, and trends in the discovery rate of JF comets as a function of their perihelion distances, the overall population of JF comets within Jupiter's region (q < 5.2 AU) up to an absolute nuclear magnitude H_N = 18.5 is estimated to be from several thousand to about 104 members. The q-distribution of JF comets shows a steep increase with q, which is consistent with JF comets coming from a flat intermediate source in the Jupiter-Saturn region.

Ultrahigh-Repetition Pulse Train with Absolute-Phase Control Produced by AN Adiabatic Raman Process

NASA Astrophysics Data System (ADS)

Katsuragawa, M.; Suzuki, T.; Shiraga, K.; Arakawa, M.; Onose, T.; Yokoyama, K.; Hong, F. L.; Misawa, K.

2010-02-01

We describe the generation of an ultrahigh-repetition-rate train of ultrashort pulses on the basis of an adiabatic Raman process. We also describe recent progress in studies toward the ultimate regime: realization of an ultrahigh-repetition-rate train of monocycle pulses with control of the absolute phase. We comment on the milestones expected in the near future in terms of the study of such novel light sources and the new field of optical science stimulated by their development.

Absolute Bunch Length Measurements at the ALS by Incoherent Synchrotron Radiation Fluctuation Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filippetto, D.; /Frascati; Sannibale, F.

2008-01-24

By analyzing the pulse to pulse intensity fluctuations of the radiation emitted by a charge particle in the incoherent part of the spectrum, it is possible to extract information about the spatial distribution of the beam. At the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory, we have developed and tested a simple scheme based on this principle that allows for the absolute measurement of the bunch length. A description of the method and the experimental results are presented.

A temporal discriminability account of children's eyewitness suggestibility.

PubMed

Bright-Paul, Alexandra; Jarrold, Christopher

2009-07-01

Children's suggestibility is typically measured using a three-stage 'event-misinformation-test' procedure. We examined whether suggestibility is influenced by the time delays imposed between these stages, and in particular whether the temporal discriminability of sources (event and misinformation) predicts performance. In a novel approach, the degree of source discriminability was calculated as the relative magnitude of two intervals (the ratio of event-misinformation and misinformation-test intervals), based on an adaptation of existing 'ratio-rule' accounts of memory. Five-year-olds (n =150) watched an event, and were exposed to misinformation, before memory for source was tested. The absolute event-test delay (12 versus 24 days) and the 'ratio' of event-misinformation/misinformation-test intervals (11:1, 3:1, 1:1, 1:3 and 1:11) were manipulated across participants. The temporal discriminability of sources, measured by the ratio, was indeed a strong predictor of suggestibility. Most importantly, if the ratio was constant (e.g. 18/6 versus 9/3 days), performance was remarkably similar despite variations in absolute delay (e.g. 24 versus 12 days). This intriguing finding not only extends the ratio-rule of distinctiveness to misinformation paradigms, but also serves to illustrate a new empirical means of differentiating between explanations of suggestibility based on interference between sources and disintegration of source information over time.

Volatile Organic Compounds: Characteristics, distribution and sources in urban schools

NASA Astrophysics Data System (ADS)

Mishra, Nitika; Bartsch, Jennifer; Ayoko, Godwin A.; Salthammer, Tunga; Morawska, Lidia

2015-04-01

Long term exposure to organic pollutants, both inside and outside school buildings may affect children's health and influence their learning performance. Since children spend significant amount of time in school, air quality, especially in classrooms plays a key role in determining the health risks associated with exposure at schools. Within this context, the present study investigated the ambient concentrations of Volatile Organic Compounds (VOCs) in 25 primary schools in Brisbane with the aim to quantify the indoor and outdoor VOCs concentrations, identify VOCs sources and their contribution, and based on these; propose mitigation measures to reduce VOCs exposure in schools. One of the most important findings is the occurrence of indoor sources, indicated by the I/O ratio >1 in 19 schools. Principal Component Analysis with Varimax rotation was used to identify common sources of VOCs and source contribution was calculated using an Absolute Principal Component Scores technique. The result showed that outdoor 47% of VOCs were contributed by petrol vehicle exhaust but the overall cleaning products had the highest contribution of 41% indoors followed by air fresheners and art and craft activities. These findings point to the need for a range of basic precautions during the selection, use and storage of cleaning products and materials to reduce the risk from these sources.

Using an interference spectrum as a short-range absolute rangefinder with fiber and wideband source

NASA Astrophysics Data System (ADS)

Hsieh, Tsung-Han; Han, Pin

2018-06-01

Recently, a new type of displacement instrument using spectral-interference has been found, which utilizes fiber and a wideband light source to produce an interference spectrum. In this work, we develop a method that measures the absolute air-gap distance by taking wavelengths at two interference spectra minima. The experimental results agree with the theoretical calculations. It is also utilized to produce and control the spectral switch, which is much easier than other previous methods using other control mechanisms. A scanning mode of this scheme for stepped surface measurement is suggested, which is verified by a standard thickness gauge test. Our scheme is different to one available on the market that may use a curve-fitting method, and some comparisons are made between our scheme and that one.

Depth encoded three-beam swept source Doppler optical coherence tomography

NASA Astrophysics Data System (ADS)

Wartak, Andreas; Haindl, Richard; Trasischker, Wolfgang; Baumann, Bernhard; Pircher, Michael; Hitzenberger, Christoph K.

2016-03-01

A novel approach for investigation of human retinal and choroidal blood flow by the means of multi-channel swept source Doppler optical coherence tomography (SS-D-OCT) system is being developed. We present preliminary in vitro measurement results for quantification of the 3D velocity vector of scatterers in a flow phantom. The absolute flow velocity of moving scatterers can be obtained without prior knowledge of flow orientation. In contrast to previous spectral domain (SD-) D-OCT investigations, that already proved the three-channel D-OCT approach to be suitable for in vivo retinal blood flow evaluation, this current work aims for a similar functional approach by means of a differing technique. To the best of our knowledge, this is the first three-channel D-OCT setup featuring a wavelength tunable laser source. Furthermore, we present a modification of our setup allowing a reduction of the former three active illumination channels to one active illumination channel and two passive channels, which only probe the illuminated sample. This joint aperture (JA) approach provides the advantage of not having to divide beam power among three beams to meet corresponding laser safety limits. The in vitro measurement results regarding the flow phantom show good agreement between theoretically calculated and experimentally obtained flow velocity values.

Absolute reactivity calibration of accelerator-driven systems after RACE-T experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jammes, C. C.; Imel, G. R.; Geslot, B.

2006-07-01

The RACE-T experiments that were held in november 2005 in the ENEA-Casaccia research center near Rome allowed us to improve our knowledge of the experimental techniques for absolute reactivity calibration at either startup or shutdown phases of accelerator-driven systems. Various experimental techniques for assessing a subcritical level were inter-compared through three different subcritical configurations SC0, SC2 and SC3, about -0.5, -3 and -6 dollars, respectively. The area-ratio method based of the use of a pulsed neutron source appears as the most performing. When the reactivity estimate is expressed in dollar unit, the uncertainties obtained with the area-ratio method were lessmore » than 1% for any subcritical configuration. The sensitivity to measurement location was about slightly more than 1% and always less than 4%. Finally, it is noteworthy that the source jerk technique using a transient caused by the pulsed neutron source shutdown provides results in good agreement with those obtained from the area-ratio technique. (authors)« less

Cyclic Diarylheptanoids from Corylus avellana Green Leafy Covers: Determination of Their Absolute Configurations and Evaluation of Their Antioxidant and Antimicrobial Activities.

PubMed

Cerulli, Antonietta; Lauro, Gianluigi; Masullo, Milena; Cantone, Vincenza; Olas, Beata; Kontek, Bogdan; Nazzaro, Filomena; Bifulco, Giuseppe; Piacente, Sonia

2017-06-23

The methanol extract of the leafy covers of Corylus avellana, source of the Italian PGI (protected geographical indication) product "Nocciola di Giffoni", afforded two new cyclic diarylheptanoids, giffonins T and U (2 and 3), along with two known cyclic diarylheptanoids, a quinic acid, flavonoid-, and citric acid derivatives. The structures of giffonins T and U were determined as highly hydroxylated cyclic diarylheptanoids by 1D and 2D NMR experiments. Their relative configurations were assigned by a combined quantum mechanical/NMR approach, comparing the experimental 13 C/ 1 H NMR chemical shift data and the related predicted values. The absolute configurations of carpinontriol B (1) and giffonins T and U (2 and 3) were assigned by comparison of their experimental electronic circular dichroism curves with the TDDFT-predicted curves. The ability of the compounds to inhibit the lipid peroxidation induced by H 2 O 2 and H 2 O 2 /Fe 2+ was determined by measuring the concentration of thiobarbituric acid reactive substances. Furthermore, the antimicrobial activity of the methanol extract of leafy covers of C. avellana and of the isolated compounds against the Gram-positive strains Bacillus cereus and Staphylococcus aureus and the Gram-negative strains Escherichia coli and Pseudomonas aeruginosa was evaluated. Carpinontriol B (1) and giffonin U (3) at 40 μg/disk caused the formation of zones of inhibition.

Verification of a Schumann Resonance Inversion Method for Global Lightning Activity in Absolute Units

NASA Astrophysics Data System (ADS)

Williams, E. R.; Guha, A.; Liu, Y.; Boldi, R. A.; Pracser, E.; Said, R.; Satori, G.; Bozoki, T.; Bor, J.; Atkinson, M.; Beggan, C.; Cummer, S.; Lyu, F.; Fain, B.; Hobara, Y.; Alexander, K.; Kulak, A.; McCraty, R.; Mlynarczyk, J.; Montanya, J.; Moore, R. C.; Neska, M.; Ortega, P.; Price, C. G.; Rawat, R.; Sato, M.; Sinha, A. K.; Yampolski, Y.

2017-12-01

The global reach of single, calibrated ELF receivers operating in the Schumann resonance (SR) band (3-50 Hz) has been verified by global maps of energetic Q-burst locations and vertical charge moment change, and by locations of independently verified transient luminous events in a wide variety of locations worldwide. It has also been previously shown that with as few as six ELF receivers in widely separated locations, multi-station, multi-modal SR parameters extracted from the SR "background" signal can be inverted to provide the centroid locations of continental lightning "chimneys" (Asia, Africa, Americas) and their respective lightning activities in absolute units (coul2 km2/sec). This inversion method involves a propagation model for the Earth-ionosphere cavity with day-night asymmetry. The Earth is now populated with more than 30 calibrated ELF receivers making continuous time series observations. This circumstance is exploited in the present study to verify the findings of the ELF inversion method. During the period May 17-20 and 23-24, 2015, two independent sets of nine ELF receivers each, in widely-separated geographical locations (first set: Antarctica (3 sites), Hungary, Japan (2 sites), Poland, Spitzbergen, and USA; second set: Antarctica, Canada, Cape Verde Island, Lithuania, New Zealand, Saudi Arabia, Scotland, Tahiti, and USA), are used to compare the locations and source strengths of lightning chimneys. Detailed comparisons will be shown over Universal Time for selected days.

Diagnostic Application of Absolute Neutron Activation Analysis in Hematology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamboni, C.B.; Oliveira, L.C.; Dalaqua, L. Jr.

2004-10-03

The Absolute Neutron Activation Analysis (ANAA) technique was used to determine element concentrations of Cl and Na in blood of healthy group (male and female blood donators), select from Blood Banks at Sao Paulo city, to provide information which can help in diagnosis of patients. This study permitted to perform a discussion about the advantages and limitations of using this nuclear methodology in hematological examinations.

Total Synthesis and Absolute Configuration of Laurenditerpenol: A Hypoxia Inducible Factor-1 Activation Inhibitor

PubMed Central

Chittiboyina, Amar G.; Kumar, Gundluru Mahesh; Carvalho, Paulo B.; Liu, Yang; Zhou, Yu-Dong; Nagle, Dale G.

2010-01-01

The absolute stereo structure of the natural product laurenditerpenol (1S, 6R, 7S, 10R, 11R, 14S, 15R) has been accomplished from eight plausible stereoisomers by its first asymmetric total synthesis in a highly convergent and flexible synthetic pathway. Six stereoisomers of laurenditerpenol were synthesized and evaluated for their biological activity. PMID:18004798

Physical fitness and performance. Cardiorespiratory fitness in girls-change from middle to high school.

PubMed

Pfeiffer, Karin A; Dowda, Marsha; Dishman, Rod K; Sirard, John R; Pate, Russell R

2007-12-01

To determine how factors are related to change in cardiorespiratory fitness (CRF) across time in middle school girls followed through high school. Adolescent girls (N = 274, 59% African American, baseline age = 13.6 +/- 0.6 yr) performed a submaximal fitness test (PWC170) in 8th, 9th, and 12th grades. Height, weight, sports participation, and physical activity were also measured. Moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) were determined by the number of blocks reported on the 3-Day Physical Activity Recall (3DPAR). Individual differences and developmental change in CRF were assessed simultaneously by calculating individual growth curves for each participant, using growth curve modeling. Both weight-relative and absolute CRF increased from 8th to 9th grade and decreased from 9th to 12th grade. On average, girls lost 0.16 kg.m.min.kg.yr in weight-relative PWC170 scores (P < 0.01) and gained 10.3 kg.m.min.yr in absolute PWC170 scores. Girls reporting two or more blocks of MVPA or one or more blocks of VPA at baseline showed an average increase in PWC170 scores of 0.40-0.52 kg.m.min.kg.yr (weight relative) and 22-28 kg.m.min.yr (absolute) in CRF. In weight-relative models, girls with higher BMI showed lower CRF (approximately 0.37 g.m.min.kg.yr), but this was not shown in absolute models. In absolute models, white girls (approximately 40 kg.m.min.yr) and sport participants (approximately 28 kg.m.min.yr) showed an increase in CRF over time. Although there were fluctuations in PWC170 scores across time, average scores decreased during 4 yr. Physical activity was related to change in CRF over time; BMI, race, and sport participation were also important factors related to change over time in CRF (depending on expression of CRF-weight-relative vs absolute). Subsequent research should focus on explaining the complex longitudinal interactions between CRF, physical activity, race, BMI, and sports participation.

Absolute Calibration of the AXAF Telescope Effective Area

NASA Technical Reports Server (NTRS)

Kellogg, E.; Cohen, L.; Edgar, R.; Evans, I.; Freeman, M.; Gaetz, T.; Jerius, D.; McDermott, W. C.; McKinnon, P.; Murray, S.;

10 CFR 36.21 - Performance criteria for sealed sources.

Code of Federal Regulations, 2014 CFR

2014-01-01

... to an external pressure (absolute) of 2 million newtons per square meter. (d) Impact. A 2-kilogram steel weight, 2.5 centimeters in diameter, must be dropped from a height of 1 meter onto the test source... from 25 hertz to 500 hertz with a peak amplitude of 5 times the acceleration of gravity. In addition...

10 CFR 36.21 - Performance criteria for sealed sources.

Code of Federal Regulations, 2012 CFR

2012-01-01

... to an external pressure (absolute) of 2 million newtons per square meter. (d) Impact. A 2-kilogram steel weight, 2.5 centimeters in diameter, must be dropped from a height of 1 meter onto the test source... from 25 hertz to 500 hertz with a peak amplitude of 5 times the acceleration of gravity. In addition...

10 CFR 36.21 - Performance criteria for sealed sources.

Code of Federal Regulations, 2013 CFR

2013-01-01

... to an external pressure (absolute) of 2 million newtons per square meter. (d) Impact. A 2-kilogram steel weight, 2.5 centimeters in diameter, must be dropped from a height of 1 meter onto the test source... from 25 hertz to 500 hertz with a peak amplitude of 5 times the acceleration of gravity. In addition...

10 CFR 36.21 - Performance criteria for sealed sources.

Code of Federal Regulations, 2011 CFR

2011-01-01

... to an external pressure (absolute) of 2 million newtons per square meter. (d) Impact. A 2-kilogram steel weight, 2.5 centimeters in diameter, must be dropped from a height of 1 meter onto the test source... from 25 hertz to 500 hertz with a peak amplitude of 5 times the acceleration of gravity. In addition...

The State Policy of Funding Higher Education under Public Budget Constraints

ERIC Educational Resources Information Center

Abankina, I. V.; Vynaryk, V. A.; Filatova, L. M.

2017-01-01

This article describes the changing face of institutions of higher education in Russia in comparison with other countries. It is shown that the ratios of funding sources for higher education in Russia are similar in structure to those in other countries. However, the absolute amounts of funding from these sources are three times less in Russia…

Results from Source-Based and Detector-Based Calibrations of a CLARREO Calibration Demonstration System

NASA Technical Reports Server (NTRS)

Angal, Amit; Mccorkel, Joel; Thome, Kurt

2016-01-01

The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission is formulated to determine long-term climate trends using SI-traceable measurements. The CLARREO mission will include instruments operating in the reflected solar (RS) wavelength region from 320 nm to 2300 nm. The Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer (SOLARIS) is the calibration demonstration system (CDS) for the reflected solar portion of CLARREO and facilitates testing and evaluation of calibration approaches. The basis of CLARREO and SOLARIS calibration is the Goddard Laser for Absolute Measurement of Response (GLAMR) that provides a radiance-based calibration at reflective solar wavelengths using continuously tunable lasers. SI-traceability is achieved via detector-based standards that, in GLAMRs case, are a set of NIST-calibrated transfer radiometers. A portable version of the SOLARIS, Suitcase SOLARIS is used to evaluate GLAMRs calibration accuracies. The calibration of Suitcase SOLARIS using GLAMR agrees with that obtained from source-based results of the Remote Sensing Group (RSG) at the University of Arizona to better than 5 (k2) in the 720-860 nm spectral range. The differences are within the uncertainties of the NIST-calibrated FEL lamp-based approach of RSG and give confidence that GLAMR is operating at 5 (k2) absolute uncertainties. Limitations of the Suitcase SOLARIS instrument also discussed and the next edition of the SOLARIS instrument (Suitcase SOLARIS- 2) is expected to provide an improved mechanism to further assess GLAMR and CLARREO calibration approaches. (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Absolutely relative or relatively absolute: violations of value invariance in human decision making.

PubMed

Teodorescu, Andrei R; Moran, Rani; Usher, Marius

2016-02-01

Making decisions based on relative rather than absolute information processing is tied to choice optimality via the accumulation of evidence differences and to canonical neural processing via accumulation of evidence ratios. These theoretical frameworks predict invariance of decision latencies to absolute intensities that maintain differences and ratios, respectively. While information about the absolute values of the choice alternatives is not necessary for choosing the best alternative, it may nevertheless hold valuable information about the context of the decision. To test the sensitivity of human decision making to absolute values, we manipulated the intensities of brightness stimuli pairs while preserving either their differences or their ratios. Although asked to choose the brighter alternative relative to the other, participants responded faster to higher absolute values. Thus, our results provide empirical evidence for human sensitivity to task irrelevant absolute values indicating a hard-wired mechanism that precedes executive control. Computational investigations of several modelling architectures reveal two alternative accounts for this phenomenon, which combine absolute and relative processing. One account involves accumulation of differences with activation dependent processing noise and the other emerges from accumulation of absolute values subject to the temporal dynamics of lateral inhibition. The potential adaptive role of such choice mechanisms is discussed.

Absolute calibration of optical streak cameras on picosecond time scales using supercontinuum generation

DOE PAGES

Patankar, S.; Gumbrell, E. T.; Robinson, T. S.; ...

2017-08-17

Here we report a new method using high stability, laser-driven supercontinuum generation in a liquid cell to calibrate the absolute photon response of fast optical streak cameras as a function of wavelength when operating at fastest sweep speeds. A stable, pulsed white light source based around the use of self-phase modulation in a salt solution was developed to provide the required brightness on picosecond timescales, enabling streak camera calibration in fully dynamic operation. The measured spectral brightness allowed for absolute photon response calibration over a broad spectral range (425-650nm). Calibrations performed with two Axis Photonique streak cameras using the Photonismore » P820PSU streak tube demonstrated responses which qualitatively follow the photocathode response. Peak sensitivities were 1 photon/count above background. The absolute dynamic sensitivity is less than the static by up to an order of magnitude. We attribute this to the dynamic response of the phosphor being lower.« less

Note: An absolute X-Y-Θ position sensor using a two-dimensional phase-encoded binary scale

NASA Astrophysics Data System (ADS)

Kim, Jong-Ahn; Kim, Jae Wan; Kang, Chu-Shik; Jin, Jonghan

2018-04-01

This Note presents a new absolute X-Y-Θ position sensor for measuring planar motion of a precision multi-axis stage system. By analyzing the rotated image of a two-dimensional phase-encoded binary scale (2D), the absolute 2D position values at two separated points were obtained and the absolute X-Y-Θ position could be calculated combining these values. The sensor head was constructed using a board-level camera, a light-emitting diode light source, an imaging lens, and a cube beam-splitter. To obtain the uniform intensity profiles from the vignette scale image, we selected the averaging directions deliberately, and higher resolution in the angle measurement could be achieved by increasing the allowable offset size. The performance of a prototype sensor was evaluated in respect of resolution, nonlinearity, and repeatability. The sensor could resolve 25 nm linear and 0.001° angular displacements clearly, and the standard deviations were less than 18 nm when 2D grid positions were measured repeatedly.

Conception and realization of a parallel-plate free-air ionization chamber for the absolute dosimetry of an ultrasoft X-ray beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Groetz, J.-E., E-mail: jegroetz@univ-fcomte.fr; Mavon, C.; Fromm, M.

2014-08-15

We report the design of a millimeter-sized parallel plate free-air ionization chamber (IC) aimed at determining the absolute air kerma rate of an ultra-soft X-ray beam (E = 1.5 keV). The size of the IC was determined so that the measurement volume satisfies the condition of charged-particle equilibrium. The correction factors necessary to properly measure the absolute kerma using the IC have been established. Particular attention was given to the determination of the effective mean energy for the 1.5 keV photons using the PENELOPE code. Other correction factors were determined by means of computer simulation (COMSOL™and FLUKA). Measurements of airmore » kerma rates under specific operating parameters of the lab-bench X-ray source have been performed at various distances from that source and compared to Monte Carlo calculations. We show that the developed ionization chamber makes it possible to determine accurate photon fluence rates in routine work and will constitute substantial time-savings for future radiobiological experiments based on the use of ultra-soft X-rays.« less

Noninvasive assessment of testicular torsion in rabbits using frequency-domain near-infrared spectroscopy: prospects for pediatric urology

NASA Astrophysics Data System (ADS)

Hallacoglu, Bertan; Matulewicz, Richard S.; Paltiel, Harriet J.; Padua, Horacio; Gargollo, Patricio; Cannon, Glenn; Alomari, Ahmad; Sassaroli, Angelo; Fantini, Sergio

2009-09-01

We present a quantitative near-IR spectroscopy study of the absolute values of oxygen saturation of hemoglobin before and after surgically induced testicular torsion in adult rabbits. Unilateral testicular torsions (0, 540, or 720 deg) on experimental testes and contralateral sham surgery on control testes are performed in four adult rabbits. A specially designed optical probe for measurements at multiple source-detector distances and a commercial frequency-domain tissue spectrometer are used to measure absolute values of testicular hemoglobin saturation. Our results show: (1) a consistent baseline absolute tissue hemoglobin saturation value of 78+/-5%, (2) a comparable tissue hemoglobin saturation of 77+/-6% after sham surgery, and (3) a significantly lower tissue hemoglobin saturation of 36+/-2% after 540- and 720-deg testicular torsion surgery. Our findings demonstrate the feasibility of performing frequency-domain, multidistance near-IR spectroscopy for absolute testicular oximetry in the assessment of testicular torsion. We conclude that near-IR spectroscopy has potential to serve as a clinical diagnostic and monitoring tool for the assessment of absolute testicular hemoglobin desaturation caused by torsion, with the possibility of serving as a complement to conventional color and spectral Doppler ultrasonography.

Absolute Calibration of Image Plate for electrons at energy between 100 keV and 4 MeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, H; Back, N L; Eder, D C

2007-12-10

The authors measured the absolute response of image plate (Fuji BAS SR2040) for electrons at energies between 100 keV to 4 MeV using an electron spectrometer. The electron source was produced from a short pulse laser irradiated on the solid density targets. This paper presents the calibration results of image plate Photon Stimulated Luminescence PSL per electrons at this energy range. The Monte Carlo radiation transport code MCNPX results are also presented for three representative incident angles onto the image plates and corresponding electron energies depositions at these angles. These provide a complete set of tools that allows extraction ofmore » the absolute calibration to other spectrometer setting at this electron energy range.« less

Absolute charge calibration of scintillating screens for relativistic electron detection

NASA Astrophysics Data System (ADS)

Buck, A.; Zeil, K.; Popp, A.; Schmid, K.; Jochmann, A.; Kraft, S. D.; Hidding, B.; Kudyakov, T.; Sears, C. M. S.; Veisz, L.; Karsch, S.; Pawelke, J.; Sauerbrey, R.; Cowan, T.; Krausz, F.; Schramm, U.

2010-03-01

We report on new charge calibrations and linearity tests with high-dynamic range for eight different scintillating screens typically used for the detection of relativistic electrons from laser-plasma based acceleration schemes. The absolute charge calibration was done with picosecond electron bunches at the ELBE linear accelerator in Dresden. The lower detection limit in our setup for the most sensitive scintillating screen (KODAK Biomax MS) was 10 fC/mm2. The screens showed a linear photon-to-charge dependency over several orders of magnitude. An onset of saturation effects starting around 10-100 pC/mm2 was found for some of the screens. Additionally, a constant light source was employed as a luminosity reference to simplify the transfer of a one-time absolute calibration to different experimental setups.

Detrital and volcanic zircon U-Pb ages from southern Mendoza (Argentina): An insight on the source regions in the northern part of the Neuquén Basin

NASA Astrophysics Data System (ADS)

Naipauer, Maximiliano; Tapia, Felipe; Mescua, José; Farías, Marcelo; Pimentel, Marcio M.; Ramos, Victor A.

2015-12-01

The infill of the Neuquén Basin recorded the Meso-Cenozoic geological and tectonic evolution of the southern Central Andes being an excellent site to investigate how the pattern of detrital zircon ages varies trough time. In this work we analyze the U-Pb (LA-MC-ICP-MS) zircon ages from sedimentary and volcanic rocks related to synrift and retroarc stages of the northern part of the Neuquén Basin. These data define the crystallization age of the synrift volcanism at 223 ± 2 Ma (Cerro Negro Andesite) and the maximum depositional age of the original synrift sediments at ca. 204 Ma (El Freno Formation). Two different pulses of rifting could be recognized according to the absolute ages, the oldest developed during the Norian and the younger during the Rhaetian-Sinemurian. The source regions of the El Freno Formation show that the Choiyoi magmatic province was the main source rock of sediment supply. An important amount of detrital zircons with Triassic ages was identified and interpreted as a source area related to the synrift magmatism. The maximum depositional age calculated for the Tordillo Formation in the Atuel-La Valenciana depocenter is at ca. 149 Ma; as well as in other places of the Neuquén Basin, the U-Pb ages calculated in the Late Jurassic Tordillo Formation do not agree with the absolute age of the Kimmeridgian-Tithonian boundary (ca. 152 Ma). The main source region of sediment in the Tordillo Formation was the Andean magmatic arc. Basement regions were also present with age peaks at the Carboniferous, Neoproterozoic, and Mesoproterozoic; these regions were probably located to the east in the San Rafael Block. The pattern of zircon ages summarized for the Late Jurassic Tordillo and Lagunillas formations were interpreted as a record of the magmatic activity during the Triassic and Jurassic in the southern Central Andes. A waning of the magmatism is inferred to have happened during the Triassic. The evident lack of ages observed around ca. 200 Ma suggests cessation of the synrift magmatism. The later increase in magmatic activity during the Early Jurassic is attributed to the onset of Andean subduction, with maximum peaks at ca. 191 and 179 Ma. The trough at ca. 165 Ma and the later increase in the Late Jurassic could be explained by changes in the relative convergence rate in the Andean subduction regime, or by the shift to a more mafic composition of the magmatism with minor zircon fertility.

Resting-State Oscillatory Activity in Children Born Small for Gestational Age: An MEG Study

PubMed Central

Boersma, Maria; de Bie, Henrica M. A.; Oostrom, Kim J.; van Dijk, Bob W.; Hillebrand, Arjan; van Wijk, Bernadette C. M.; Delemarre-van de Waal, Henriëtte A.; Stam, Cornelis J.

2013-01-01

Growth restriction in utero during a period that is critical for normal growth of the brain, has previously been associated with deviations in cognitive abilities and brain anatomical and functional changes. We measured magnetoencephalography (MEG) in 4- to 7-year-old children to test if children born small for gestational age (SGA) show deviations in resting-state brain oscillatory activity. Children born SGA with postnatally spontaneous catch-up growth [SGA+; six boys, seven girls; mean age 6.3 year (SD = 0.9)] and children born appropriate for gestational age [AGA; seven boys, three girls; mean age 6.0 year (SD = 1.2)] participated in a resting-state MEG study. We calculated absolute and relative power spectra and used non-parametric statistics to test for group differences. SGA+ and AGA born children showed no significant differences in absolute and relative power except for reduced absolute gamma band power in SGA children. At the time of MEG investigation, SGA+ children showed significantly lower head circumference (HC) and a trend toward lower IQ, however there was no association of HC or IQ with absolute or relative power. Except for reduced absolute gamma band power, our findings suggest normal brain activity patterns at school age in a group of children born SGA in which spontaneous catch-up growth of bodily length after birth occurred. Although previous findings suggest that being born SGA alters brain oscillatory activity early in neonatal life, we show that these neonatal alterations do not persist at early school age when spontaneous postnatal catch-up growth occurs after birth. PMID:24068993

Determination of the Absolute Number of Cytokine mRNA Molecules within Individual Activated Human T Cells

NASA Technical Reports Server (NTRS)

Karr, Laurel J.; Marshall, Gwen; Hockett, Richard D.; Bucy, R. Pat; Curreri, Peter A. (Technical Monitor)

2002-01-01

A primary function of activated T cells is the expression and subsequent secretion of cytokines, which orchestrate the differentiation of other lymphocytes, modulate antigen presenting cell activity, and alter vascular endothelium to mediate an immune response. Since many features of immune regulation probably result from modest alterations of endogenous rates of multiple interacting processes, quantitative analysis of the frequency and specific activity of individual T cells is critically important. Using a coordinated set of quantitative methods, the absolute number of molecules of several key cytokine mRNA species in individual T cells has been determined. The frequency of human blood T cells activated in vitro by mitogens and recall protein antigens was determined by intracellular cytokine protein staining, in situ hybridization for cytokine mRNA, and by limiting dilution analysis for cytokine mRNA+ cells. The absolute number of mRNA molecules was simultaneously determined in both homogenates of the entire population of cells and in individual cells obtained by limiting dilution, using a quantitative, competitive RT-PCR assay. The absolute numbers of mRNA molecules in a population of cells divided by the frequency of individual positive cells, yielded essentially the same number of mRNA molecules per cell as direct analysis of individual cells by limiting dilution analysis. Mean numbers of mRNA per positive cell from both mitogen and antigen activated T cells, using these stimulation conditions, were 6000 for IL-2, 6300 for IFN-gamma, and 1600 for IL-4.

A mechanism of midlatitude noontime foE long-term variations inferred from European observations

NASA Astrophysics Data System (ADS)

Mikhailov, A. V.; Perrone, L.; Nusinov, A. A.

2017-04-01

Manually scaled June noontime monthly median foE values at three European stations Rome, Juliusruh, and Slough/Chilton were used to understand the mechanism of foE long-term variations. The 11 year running mean smoothed foE manifests long-term (for some solar cycles) variations with the rising phase at the end of 1960-1985 and the falling phase after 1985. A close relationship (even in details) between (foEave)11y and (R12)11y variations with the correlation coefficient of 0.996 (absolutely significant according to Fisher F criterion) suggests that the Sun is the source of these (foEave)11y long-term variations. After removing solar activity long-term variations the residual (foEave)11y trend is very small ( 0.029% per decade) being absolutely insignificant. This means that all (foEave)11y variations are removed with one solar activity index, (R12)11y, i.e., this means that long-term variations are fully controlled by solar activity. Theory of midlatitude daytime E region tells us that long-term variations of solar EUV in two lines λ = 977 Å (CIII) and λ = 1025.7 Å (HLyβ) and X-ray radiation with λ < 100 Å (both manifesting the same long-term variations with the rising phase at the end of 1960-1985 and the falling phase after 1985) are responsible for the observed (foEave)11y variations. Therefore, the observed daytime midlatitude foE long-term variations have a natural (not anthropogenic) origin related to long-term variations of solar activity. No peculiarities in relation with the last deep solar minimum in 2008-2009 have been revealed.

Calculated performance of a mercury-compressor-jet powered airplane using a nuclear reactor as an energy source

NASA Technical Reports Server (NTRS)

Doyle, R B

1951-01-01

An analysis was made at a flight Mach number of 1.5, an altitude of 45,000 feet, a turbine-inlet temperature of 1460 degrees R, of a mercury compressor-jet powered airplane using a nuclear reactor as an energy source. The calculations covered a range of turbine-exhaust and turbine-inlet pressures and condenser-inlet Mach numbers. For a turbine--inlet pressure of 40 pounds per square inch absolute, a turbine-exhaust pressure of 14 pounds per square inch absolute, and a condenser-inlet Mach number of 0.23 the calculated airplane gross weight required to carry a 20,000 pound payload was 322000 pounds and the reactor heat release per unit volume was 8.9 kilowatts per cubic inch. These do not represent optimum operating conditions.

Radiometric properties of the NS001 Thematic Mapper Simulator aircraft multispectral scanner

NASA Technical Reports Server (NTRS)

Markham, Brian L.; Ahmad, Suraiya P.

1990-01-01

Laboratory tests of the NS001 TM are described emphasizing absolute calibration to determine the radiometry of the simulator's reflective channels. In-flight calibration of the data is accomplished with the NS001 internal integrating-sphere source because instabilities in the source can limit the absolute calibration. The data from 1987-89 indicate uncertainties of up to 25 percent with an apparent average uncertainty of about 15 percent. Also identified are dark current drift and sensitivity changes along the scan line, random noise, and nonlinearity which contribute errors of 1-2 percent. Uncertainties similar to hysteresis are also noted especially in the 2.08-2.35-micron range which can reduce sensitivity and cause errors. The NS001 TM Simulator demonstrates a polarization sensitivity that can generate errors of up to about 10 percent depending on the wavelength.

An analysis of MCNP cross-sections and tally methods for low-energy photon emitters.

PubMed

Demarco, John J; Wallace, Robert E; Boedeker, Kirsten

2002-04-21

Monte Carlo calculations are frequently used to analyse a variety of radiological science applications using low-energy (10-1000 keV) photon sources. This study seeks to create a low-energy benchmark for the MCNP Monte Carlo code by simulating the absolute dose rate in water and the air-kerma rate for monoenergetic point sources with energies between 10 keV and 1 MeV. The analysis compares four cross-section datasets as well as the tally method for collision kerma versus absorbed dose. The total photon attenuation coefficient cross-section for low atomic number elements has changed significantly as cross-section data have changed between 1967 and 1989. Differences of up to 10% are observed in the photoelectric cross-section for water at 30 keV between the standard MCNP cross-section dataset (DLC-200) and the most recent XCOM/NIST tabulation. At 30 keV, the absolute dose rate in water at 1.0 cm from the source increases by 7.8% after replacing the DLC-200 photoelectric cross-sections for water with those from the XCOM/NIST tabulation. The differences in the absolute dose rate are analysed when calculated with either the MCNP absorbed dose tally or the collision kerma tally. Significant differences between the collision kerma tally and the absorbed dose tally can occur when using the DLC-200 attenuation coefficients in conjunction with a modern tabulation of mass energy-absorption coefficients.

Laboratory Studies in UV and EUV Solar Physics

NASA Technical Reports Server (NTRS)

Wagner, William J. (Technical Monitor); Kohl, John L.

2005-01-01

A new 5 GHZ Electron Cyclotron Resonance (ECR) ion source for SAO's Ion Beam Experiment was designed, built and tested. Absolute cross sections were measured for electron impact excitation (EIE) in C(2+) (2s2p (3)P(sup o) - 2p(sup 2) (3)P), and empirical EIE rate coefficients were derived. The absolute cross section for EIE in Si(2+) (3s3p (3)P(sup o) - 3s3p (1)P(sup o)) was measured, and our experimental values for absolute cross sections for EIE in C(3+) (2s (2)S - 2p (2)P(sup o)) were reanalyzed and compared to values obtained by other experimental methods and by theory. In addition, a paper was published. The development and testing of the new ion source, the Si(2+) EIE measurements, and the reevaluation of the cross sections for C(3+) resulted from the Ph.D. research of Paul H. Janzen who completed the degree requirements for the Harvard University Department of Physics in 2002. John Kohl served as the Ph.D.Thesis Advisor. Because of delays in bringing the new ion source on line, the measurements of EIE in C(2+) (2s2p (3)P(sup o) - (2)p(sup 2) (3)P) were not completed until 2004. Preparations for measurements of EIE in C(2+) (1s(sup 2) (1)S - 2s2p (1)P(sup o)) are currently underway.

Dosimetry of 192Ir sources used for endovascular brachytherapy

NASA Astrophysics Data System (ADS)

Reynaert, N.; Van Eijkeren, M.; Taeymans, Y.; Thierens, H.

2001-02-01

An in-phantom calibration technique for 192Ir sources used for endovascular brachytherapy is presented. Three different source lengths were investigated. The calibration was performed in a solid phantom using a Farmer-type ionization chamber at source to detector distances ranging from 1 cm to 5 cm. The dosimetry protocol for medium-energy x-rays extended with a volume-averaging correction factor was used to convert the chamber reading to dose to water. The air kerma strength of the sources was determined as well. EGS4 Monte Carlo calculations were performed to determine the depth dose distribution at distances ranging from 0.6 mm to 10 cm from the source centre. In this way we were able to convert the absolute dose rate at 1 cm distance to the reference point chosen at 2 mm distance. The Monte Carlo results were confirmed by radiochromic film measurements, performed with a double-exposure technique. The dwell times to deliver a dose of 14 Gy at the reference point were determined and compared with results given by the source supplier (CORDIS). They determined the dwell times from a Sievert integration technique based on the source activity. The results from both methods agreed to within 2% for the 12 sources that were evaluated. A Visual Basic routine that superimposes dose distributions, based on the Monte Carlo calculations and the in-phantom calibration, onto intravascular ultrasound images is presented. This routine can be used as an online treatment planning program.

Volumetric vessel reconstruction method for absolute blood flow velocity measurement in Doppler OCT images

NASA Astrophysics Data System (ADS)

Qi, Li; Zhu, Jiang; Hancock, Aneeka M.; Dai, Cuixia; Zhang, Xuping; Frostig, Ron D.; Chen, Zhongping

2017-02-01

Doppler optical coherence tomography (DOCT) is considered one of the most promising functional imaging modalities for neuro biology research and has demonstrated the ability to quantify cerebral blood flow velocity at a high accuracy. However, the measurement of total absolute blood flow velocity (BFV) of major cerebral arteries is still a difficult problem since it not only relates to the properties of the laser and the scattering particles, but also relates to the geometry of both directions of the laser beam and the flow. In this paper, focusing on the analysis of cerebral hemodynamics, we presents a method to quantify the total absolute blood flow velocity in middle cerebral artery (MCA) based on volumetric vessel reconstruction from pure DOCT images. A modified region growing segmentation method is first used to localize the MCA on successive DOCT B-scan images. Vessel skeletonization, followed by an averaging gradient angle calculation method, is then carried out to obtain Doppler angles along the entire MCA. Once the Doppler angles are determined, the absolute blood flow velocity of each position on the MCA is easily found. Given a seed point position on the MCA, our approach could achieve automatic quantification of the fully distributed absolute BFV. Based on experiments conducted using a swept-source optical coherence tomography system, our approach could achieve automatic quantification of the fully distributed absolute BFV across different vessel branches in the rodent brain.

[Tracing Sources of Sulfate Aerosol in Nanjing Northern Suburb Using Sulfur and Oxygen Isotopes].

PubMed

Wei, Ying; Guo, Zhao-bing; Ge, Xin; Zhu, Sheng-nan; Jiang, Wen-juan; Shi, Lei; Chen, Shu

2015-04-01

Abstract: To trace the sources of sulfate contributing to atmospheric aerosol, PM2.5 samples for isotopic analysis were collected in Nanjing northern suburb during January 2014. The sulfur and oxygen isotopic compositions of sulfate from these samples were determined by EA-IRMS. Source identification and apportionment were carried out using stable isotopic and chemical evidences, combined with absolute principal component analysis (APCA) method. The Δ34S values of aerosol sulfate ranged from 2.7 per thousand to 6.4 per thousand, with an average of 5.0 per thousand ± 0.9 per thousand, while the Δ18O values ranged from 10.6 per thousand to 16.1 per thousand, with an average of 12.5 per thousand ± 1.37 per thousand. In conjunction with air mass trajectories, the results suggested that aerosol sulfates were controlled by a dominance of local anthropogenic sulfate, followed by the contributions of long-distance transported sulfate. There was a minor effect of some other low-Δ34S valued sulfates, which might be expected from biogenic sources. Absolute principal component analysis results showed that the contributions of anthropogenic sulfate and long-distance transported sulfate were 46.74% and 31.54%, respectively.

MEANS FOR VISUALIZING FLUID FLOW PATTERNS

DOEpatents

Lynch, F.E.; Palmer, L.D.; Poppendick, H.F.; Winn, G.M.

1961-05-16

An apparatus is given for determining both the absolute and relative velocities of a phosphorescent fluid flowing through a transparent conduit. The apparatus includes a source for exciting a narrow trsnsverse band of the fluid to phosphorescence, detecting means such as a camera located downstream from the exciting source to record the shape of the phosphorescent band as it passes, and a timer to measure the time elapsed between operation of the exciting source and operation of the camera.

Groundwater quality assessment and pollution source apportionment in an intensely exploited region of northern China.

PubMed

Zhang, Qianqian; Wang, Huiwei; Wang, Yanchao; Yang, Mingnan; Zhu, Liang

2017-07-01

Deterioration in groundwater quality has attracted wide social interest in China. In this study, groundwater quality was monitored during December 2014 at 115 sites in the Hutuo River alluvial-pluvial fan region of northern China. Results showed that 21.7% of NO 3 - and 51.3% of total hardness samples exceeded grade III of the national quality standards for Chinese groundwater. In addition, results of gray relationship analysis (GRA) show that 64.3, 10.4, 21.7, and 3.6% of samples were within the I, II, IV, and V grades of groundwater in the Hutuo River region, respectively. The poor water quality in the study region is due to intense anthropogenic activities as well as aquifer vulnerability to contamination. Results of principal component analysis (PCA) revealed three major factors: (1) domestic wastewater and agricultural runoff pollution (anthropogenic activities), (2) water-rock interactions (natural processes), and (3) industrial wastewater pollution (anthropogenic activities). Using PCA and absolute principal component scores-multivariate linear regression (APCS-MLR), results show that domestic wastewater and agricultural runoff are the main sources of groundwater pollution in the Hutuo River alluvial-pluvial fan area. Thus, the most appropriate methods to prevent groundwater quality degradation are to improve capacities for wastewater treatment and to optimize fertilization strategies.

Spectroscopic characterization of H 2 and D 2 helicon plasmas generated by a resonant antenna for neutral beam applications in fusion

NASA Astrophysics Data System (ADS)

Marini, C.; Agnello, R.; Duval, B. P.; Furno, I.; Howling, A. A.; Jacquier, R.; Karpushov, A. N.; Plyushchev, G.; Verhaegh, K.; Guittienne, Ph.; Fantz, U.; Wünderlich, D.; Béchu, S.; Simonin, A.

2017-03-01

A new generation of neutral beam systems will be required in future fusion reactors, such as DEMO, able to deliver high power (up to 50 MW) with high (800 keV or higher) neutral energy. Only negative ion beams may be able to attain this performance, which has encouraged a strong research focus on negative ion production from both surface and volumetric plasma sources. A novel helicon plasma source, based on the resonant birdcage network antenna configuration, is currently under study at the Swiss Plasma Centre before installation on the Cybele negative ion source at the Institute for Magnetic Fusion Research, CEA, Cadarache, France. This source is driven by up to 10 kW at 13.56 MHz, and is being tested on a linear resonant antenna ion device. Passive spectroscopic measurements of the first three Balmer lines α, β and γ and of the Fulcher-α bands were performed with an f/2 spectrometer, for both hydrogen and deuterium. Multiple viewing lines and an absolute intensity calibration were used to determine the plasma radiance profile, with a spatial resolution  <3 mm. A minimum Fisher regularization algorithm was applied to obtain the absolute emissivity profile for each emission line for cylindrical symmetry, which was experimentally confirmed. An uncertainty estimate of the inverted profiles was performed using a Monte Carlo approach. Finally, a radiofrequency-compensated Langmuir probe was inserted to measured the electron temperature and density profiles. The absolute line emissivities are interpreted using the collisional-radiative code YACORA which estimates the degree of dissociation and the distribution of the atomic and molecular species, including the negative ion density. This paper reports the results of a power scan up to 5 kW in conditions satisfying Cybele requirements for the plasma source, namely a low neutral pressure, p≤slant 0.3 Pa and magnetic field B≤slant 150 G.

Theory of Maxwell's fish eye with mutually interacting sources and drains

NASA Astrophysics Data System (ADS)

Leonhardt, Ulf; Sahebdivan, Sahar

2015-11-01

Maxwell's fish eye is predicted to image with a resolution not limited by the wavelength of light. However, interactions between sources and drains may ruin the subwavelength imaging capabilities of this and similar absolute optical instruments. Nevertheless, as we show in this paper, at resonance frequencies of the device, an array of drains may resolve a single source, or alternatively, a single drain may scan an array of sources, no matter how narrowly spaced they are. It seems that near-field information can be obtained from far-field distances.

Monitoring environmental burden reduction from household waste prevention.

PubMed

Matsuda, Takeshi; Hirai, Yasuhiro; Asari, Misuzu; Yano, Junya; Miura, Takahiro; Ii, Ryota; Sakai, Shin-Ichi

2018-01-01

In this study, the amount of prevented household waste in Kyoto city was quantified using three methods. Subsequently, the greenhouse gas (GHG) emission reduction by waste prevention was calculated in order to monitor the impact of waste prevention. The methods of quantification were "relative change from baseline year (a)," "absolute change from potential waste generation (b)," and "absolute amount of activities (c)." Method (a) was popular for measuring waste prevention, but method (b) was the original approach to determine the absolute amount of waste prevention by estimating the potential waste generation. Method (c) also provided the absolute value utilizing the information of activities. Methods (b) and (c) enable the evaluation of the waste prevention activities with a similar baseline for recycling. Methods (b) and (c) gave significantly higher GHG reductions than method (a) because of the difference in baseline between them. Therefore, setting a baseline is very important for evaluating waste prevention. In practice, when focusing on the monitoring of a specific policy or campaign, method (a) is an appropriate option. On the other hand, when comparing the total impact of waste prevention to that of recycling, methods (b) and (c) should be applied. Copyright © 2017 Elsevier Ltd. All rights reserved.

Non-destructive method for determining neutron exposure

DOEpatents

Gold, R.; McElroy, W.N.

1983-11-01

A non-destructive method for determination of neutron exposure in an object, such as a reactor pressure vessel, is based on the observation of characteristic gamma-rays emitted by activation products in the object by using a unique continuous gamma-ray spectrometer. The spectrometer views the object through appropriate collimators to determine the absolute emission rate of these characteristic gamma-rays, thereby ascertaining the absolute activity of given activation products in the object. These data can then be used to deduce the spatial and angular dependence of neutron exposure at regions of interest within the object.

Instrument demonstration effort for the CLARREO mission

NASA Astrophysics Data System (ADS)

Grandmont, Frédéric; Moreau, Louis; Bourque, Hugo; Taylor, Joe; Girard, Frédéric; Larouche, Martin; Veilleux, James

2017-11-01

NASA and other national agencies ask the National Research Council (NRC) once every decade to look out ten or more years into the future and prioritize research areas, observations, and notional missions to make those observations. The latest such scientific community consultation referred to as the Decadal Survey (DS), was completed in 2007 [1]. DS thematic panels developed 35 missions from more than 100 missions proposed, from which the DS Executive Committee synthesized 17 missions, with suggested order presented in three time-phased blocks. The first block with aim for near term launch (2010-2013) included four missions. The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission is one of them. The CLARREO mission was classified as a Small Mission to be contained in a 300 M US$ budgetary envelope. CLARREO will provide a benchmark climate record that is global, accurate in perpetuity, tested against independent strategies that reveal systematic errors, and pinned to international standards. The long term objective thus suggests that NOAA or NASA will fly the CLARREO instrument suite on an operational basis following the first scientific experiment The CLARREO missions will conduct the following observations: 1. Absolute spectrally-resolved measurements of terrestrial thermal emission with an absolute accuracy of 0.1 K in brightness temperature (3σ or 99% confidence limits.) The measurements should cover most of the thermal spectrum. 2. Absolute spectrally-resolved measurements of the solar radiation reflected from Earth. The measurements should cover the part of the solar spectrum most important to climate, including the near-ultraviolet, visible, and near-infrared. 3. Independent measurements of atmospheric temperature, pressure, and humidity using Global Positioning System (GPS) occultation measurements of atmospheric refraction. 4. Serve as a high accuracy calibration standard for use by the broadband CERES instruments on-orbit. Following the DS conclusion, and considering the early development stage of the mission, NASA funded three Instrument Incubator Programs (IIP) to push instrument concepts to a higher level of maturity. A joint proposal between University of Wisconsin (UW) and Harvard University was selected to address the first above objective and part of the fourth one in the corresponding spectral region. In order to achieve this goal, four complementary technologies are to be developed [2]: (1) On-orbit Absolute Radiance Standard (OARS), a high emissivity blackbody source that uses multiple miniature phase-change cells to provide a revolutionary on-orbit standard with absolute temperature accuracy proven over a wide range of temperatures. (2) On-orbit Cavity Emissivity Modules (OCEMs), providing a source (quantum cascade laser, QCL, or "Heated Halo") to measure any change in the cavity emissivity of the OARS. (3) On-orbit Spectral Response Module (OSRM), a source for spectral response measurements using a nearly monochromatic QCL source configured to uniformly fill the sensor field-of-view. (4) Dual Absolute Radiance Interferometers (DARI), providing spectral coverage from 3.3 to 50 μm that can be inter-compared to dissect any unexpected systematic errors in overlapping spectral regions. ABB's GFI (Generic Flight Interferometer) has been selected as the favoured architecture for the DARI, mainly due to the maturity of the design and its space heritage. A GFI with commercial grade components was optimised for the selected spectral range. The architecture of the GFI will ensure a high response stability between calibrations.

Proprioceptive deficit in individuals with unilateral tearing of the anterior cruciate ligament after active evaluation of the sense of joint position.

PubMed

Cossich, Victor; Mallrich, Frédéric; Titonelli, Victor; de Sousa, Eduardo Branco; Velasques, Bruna; Salles, José Inácio

2014-01-01

To ascertain whether the proprioceptive deficit in the sense of joint position continues to be present when patients with a limb presenting a deficient anterior cruciate ligament (ACL) are assessed by testing their active reproduction of joint position, in comparison with the contralateral limb. Twenty patients with unilateral ACL tearing participated in the study. Their active reproduction of joint position in the limb with the deficient ACL and in the healthy contralateral limb was tested. Meta-positions of 20% and 50% of the maximum joint range of motion were used. Proprioceptive performance was determined through the values of the absolute error, variable error and constant error. Significant differences in absolute error were found at both of the positions evaluated, and in constant error at 50% of the maximum joint range of motion. When evaluated in terms of absolute error, the proprioceptive deficit continues to be present even when an active evaluation of the sense of joint position is made. Consequently, this sense involves activity of both intramuscular and tendon receptors.

Longitudinal Changes in AbsoluteVO2peak, Physical Activity Level, Body Mass Index, and Overweightedness among Adolescents in Vocational and Non-Vocational Studies

PubMed Central

Lagestad, Pål; Floan, Oddbjørn; Moa, Ivar Fossland

2017-01-01

The purpose of the study was to examine differences in physical activity level, physical fitness, body mass index, and overweight among adolescents in vocational and non-vocational studies, at the age of 14, 16, and 19, using a 5-year longitudinal design. Students in sport studies had the highest absoluteVO2peak and higher physical activity levels, than students in vocational subjects and students with a specialization in general studies. However, there were no significant differences between students in vocational subjects and students with a specialization in general studies according to absoluteVO2peak and physical activity levels. Students in vocational subjects were significantly more overweight/obese at 19 years of age, compared with the other students. Our findings support previous research pointing to overweightedness as being more widespread among adolescents in vocational programs than in non-vocational programs. However, differences in the physical activity level and physical fitness do not seem to explain these differences. PMID:28871279

The brightest high-latitude 12-micron IRAS sources

NASA Technical Reports Server (NTRS)

Hacking, P.; Beichman, C.; Chester, T.; Neugebauer, G.; Emerson, J.

1985-01-01

The Infrared Astronomical Satellite (IRAS) Point Source catalog was searched for sources brighter than 28 Jy (0 mag) at 12 microns with absolute galactic latitude greater than 30 deg excluding the Large Magellanic Cloud. The search resulted in 269 sources, two of which are the galaxies NGC 1068 and M82. The remaining 267 sources are identified with, or have infrared color indices consistent with late-type stars some of which show evidence of circumstellar dust shells. Seven sources are previously uncataloged stars. K and M stars without circumstellar dust shells, M stars with circumstellar dust shells, and carbon stars occupy well-defined regions of infrared color-color diagrams.

Quasar spectral variability from the XMM-Newton serendipitous source catalogue

NASA Astrophysics Data System (ADS)

Serafinelli, R.; Vagnetti, F.; Middei, R.

2017-04-01

Context. X-ray spectral variability analyses of active galactic nuclei (AGN) with moderate luminosities and redshifts typically show a "softer when brighter" behaviour. Such a trend has rarely been investigated for high-luminosity AGNs (Lbol ≳ 1044 erg/s), nor for a wider redshift range (e.g. 0 ≲ z ≲ 5). Aims: We present an analysis of spectral variability based on a large sample of 2700 quasars, measured at several different epochs, extracted from the fifth release of the XMM-Newton Serendipitous Source Catalogue. Methods: We quantified the spectral variability through the parameter β defined as the ratio between the change in the photon index Γ and the corresponding logarithmic flux variation, β = -ΔΓ/Δlog FX. Results: Our analysis confirms a softer when brighter behaviour for our sample, extending the previously found general trend to high luminosity and redshift. We estimate an ensemble value of the spectral variability parameter β = -0.69 ± 0.03. We do not find dependence of β on redshift, X-ray luminosity, black hole mass or Eddington ratio. A subsample of radio-loud sources shows a smaller spectral variability parameter. There is also some change with the X-ray flux, with smaller β (in absolute value) for brighter sources. We also find significant correlations for a small number of individual sources, indicating more negative values for some sources.

Measurement of the absolute neutron beam polarization from a supermirror polarizer and the absolute efficiency of a neutron spin rotator for the NPDGamma experiment using a polarized 3He neutron spin-filter

NASA Astrophysics Data System (ADS)

Musgrave, M. M.; Baeßler, S.; Balascuta, S.; Barrón-Palos, L.; Blyth, D.; Bowman, J. D.; Chupp, T. E.; Cianciolo, V.; Crawford, C.; Craycraft, K.; Fomin, N.; Fry, J.; Gericke, M.; Gillis, R. C.; Grammer, K.; Greene, G. L.; Hamblen, J.; Hayes, C.; Huffman, P.; Jiang, C.; Kucuker, S.; McCrea, M.; Mueller, P. E.; Penttilä, S. I.; Snow, W. M.; Tang, E.; Tang, Z.; Tong, X.; Wilburn, W. S.

2018-07-01

Accurately measuring the neutron beam polarization of a high flux, large area neutron beam is necessary for many neutron physics experiments. The Fundamental Neutron Physics Beamline (FnPB) at the Spallation Neutron Source (SNS) is a pulsed neutron beam that was polarized with a supermirror polarizer for the NPDGamma experiment. The polarized neutron beam had a flux of ∼ 109 neutrons per second per cm2 and a cross sectional area of 10 × 12 cm2. The polarization of this neutron beam and the efficiency of a RF neutron spin rotator installed downstream on this beam were measured by neutron transmission through a polarized 3He neutron spin-filter. The pulsed nature of the SNS enabled us to employ an absolute measurement technique for both quantities which does not depend on accurate knowledge of the phase space of the neutron beam or the 3He polarization in the spin filter and is therefore of interest for any experiments on slow neutron beams from pulsed neutron sources which require knowledge of the absolute value of the neutron polarization. The polarization and spin-reversal efficiency measured in this work were done for the NPDGamma experiment, which measures the parity violating γ-ray angular distribution asymmetry with respect to the neutron spin direction in the capture of polarized neutrons on protons. The experimental technique, results, systematic effects, and applications to neutron capture targets are discussed.

Absolute Configuration from Different Multifragmentation Pathways in Light-Induced Coulomb Explosion Imaging.

PubMed

Pitzer, Martin; Kastirke, Gregor; Kunitski, Maksim; Jahnke, Till; Bauer, Tobias; Goihl, Christoph; Trinter, Florian; Schober, Carl; Henrichs, Kevin; Becht, Jasper; Zeller, Stefan; Gassert, Helena; Waitz, Markus; Kuhlins, Andreas; Sann, Hendrik; Sturm, Felix; Wiegandt, Florian; Wallauer, Robert; Schmidt, Lothar Ph H; Johnson, Allan S; Mazenauer, Manuel; Spenger, Benjamin; Marquardt, Sabrina; Marquardt, Sebastian; Schmidt-Böcking, Horst; Stohner, Jürgen; Dörner, Reinhard; Schöffler, Markus; Berger, Robert

2016-08-18

The absolute configuration of individual small molecules in the gas phase can be determined directly by light-induced Coulomb explosion imaging (CEI). Herein, this approach is demonstrated for ionization with a single X-ray photon from a synchrotron light source, leading to enhanced efficiency and faster fragmentation as compared to previous experiments with a femtosecond laser. In addition, it is shown that even incomplete fragmentation pathways of individual molecules from a racemic CHBrClF sample can give access to the absolute configuration in CEI. This leads to a significant increase of the applicability of the method as compared to the previously reported complete break-up into atomic ions and can pave the way for routine stereochemical analysis of larger chiral molecules by light-induced CEI. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optoelectronic device for the measurement of the absolute linear position in the micrometric displacement range

NASA Astrophysics Data System (ADS)

Morlanes, Tomas; de la Pena, Jose L.; Sanchez-Brea, Luis M.; Alonso, Jose; Crespo, Daniel; Saez-Landete, Jose B.; Bernabeu, Eusebio

2005-07-01

In this work, an optoelectronic device that provides the absolute position of a measurement element with respect to a pattern scale upon switch-on is presented. That means that there is not a need to perform any kind of transversal displacement after the startup of the system. The optoelectronic device is based on the process of light propagation passing through a slit. A light source with a definite size guarantees the relation of distances between the different elements that constitute our system and allows getting a particular optical intensity profile that can be measured by an electronic post-processing device providing the absolute location of the system with a resolution of 1 micron. The accuracy of this measuring device is restricted to the same limitations of any incremental position optical encoder.

Multiwavelength Observations of the Dwarf Seyfert 1 Galaxy POX 52

NASA Astrophysics Data System (ADS)

Thornton, Carol E.; Barth, A. J.; Ho, L. C.; Rutledge, R. E.; Greene, J. E.

2006-12-01

POX 52 is an unusual narrow-line Seyfert 1 galaxy, having an estimated black hole mass of order 105 solar masses and a dwarf host galaxy with an absolute magnitude of only MV = -17.6, which gives us a unique opportunity to study black hole-bulge relations in the low-mass regime. We present new observations from a multiwavelength campaign to study its active nucleus and host galaxy. The data include observations from the Chandra and XMM-Newton Observatories, the Hubble Space Telescope, and the Very Large Array. Chandra data show a highly variable point source with a 2.0 10.0 keV luminosity of 0.7 * 1042 ergs/s. We will also describe the X-ray spectral shape, the structure of the host galaxy as determined from GALFIT modeling of the HST ACS/HRC images, and the spectral energy distribution of the active nucleus.

Dimensional Error in Rapid Prototyping with Open Source Software and Low-cost 3D-printer

PubMed Central

Andrade-Delgado, Laura; Telich-Tarriba, Jose E.; Fuente-del-Campo, Antonio; Altamirano-Arcos, Carlos A.

2018-01-01

Summary: Rapid prototyping models (RPMs) had been extensively used in craniofacial and maxillofacial surgery, especially in areas such as orthognathic surgery, posttraumatic or oncological reconstructions, and implantology. Economic limitations are higher in developing countries such as Mexico, where resources dedicated to health care are limited, therefore limiting the use of RPM to few selected centers. This article aims to determine the dimensional error of a low-cost fused deposition modeling 3D printer (Tronxy P802MA, Shenzhen, Tronxy Technology Co), with Open source software. An ordinary dry human mandible was scanned with a computed tomography device. The data were processed with open software to build a rapid prototype with a fused deposition machine. Linear measurements were performed to find the mean absolute and relative difference. The mean absolute and relative difference was 0.65 mm and 1.96%, respectively (P = 0.96). Low-cost FDM machines and Open Source Software are excellent options to manufacture RPM, with the benefit of low cost and a similar relative error than other more expensive technologies. PMID:29464171

Dimensional Error in Rapid Prototyping with Open Source Software and Low-cost 3D-printer.

PubMed

Rendón-Medina, Marco A; Andrade-Delgado, Laura; Telich-Tarriba, Jose E; Fuente-Del-Campo, Antonio; Altamirano-Arcos, Carlos A

2018-01-01

Rapid prototyping models (RPMs) had been extensively used in craniofacial and maxillofacial surgery, especially in areas such as orthognathic surgery, posttraumatic or oncological reconstructions, and implantology. Economic limitations are higher in developing countries such as Mexico, where resources dedicated to health care are limited, therefore limiting the use of RPM to few selected centers. This article aims to determine the dimensional error of a low-cost fused deposition modeling 3D printer (Tronxy P802MA, Shenzhen, Tronxy Technology Co), with Open source software. An ordinary dry human mandible was scanned with a computed tomography device. The data were processed with open software to build a rapid prototype with a fused deposition machine. Linear measurements were performed to find the mean absolute and relative difference. The mean absolute and relative difference was 0.65 mm and 1.96%, respectively ( P = 0.96). Low-cost FDM machines and Open Source Software are excellent options to manufacture RPM, with the benefit of low cost and a similar relative error than other more expensive technologies.

A radio telescope for the calibration of radio sources at 32 gigahertz

NASA Technical Reports Server (NTRS)

Gatti, M. S.; Stewart, S. R.; Bowen, J. G.; Paulsen, E. B.

1994-01-01

A 1.5-m-diameter radio telescope has been designed, developed, and assembled to directly measure the flux density of radio sources in the 32-GHz (Ka-band) frequency band. The main goal of the design and development was to provide a system that could yield the greatest absolute accuracy yet possible with such a system. The accuracy of the measurements have a heritage that is traceable to the National Institute of Standards and Technology. At the present time, the absolute accuracy of flux density measurements provided by this telescope system, during Venus observations at nearly closest approach to Earth, is plus or minus 5 percent, with an associated precision of plus or minus 2 percent. Combining a cooled high-electron mobility transistor low-noise amplifier, twin-beam Dicke switching antenna, and accurate positioning system resulted in a state-of-the-art system at 32 GHz. This article describes the design and performance of the system as it was delivered to the Owens Valley Radio Observatory to support direct calibrations of the strongest radio sources at Ka-band.

Gravity increase before the 2015 Mw 7.8 Nepal earthquake

NASA Astrophysics Data System (ADS)

Chen, Shi; Liu, Mian; Xing, Lelin; Xu, Weimin; Wang, Wuxing; Zhu, Yiqing; Li, Hui

2016-01-01

The 25 April 2015 Nepal earthquake (Mw 7.8) ruptured a segment of the Himalayan front fault zone. Four absolute gravimetric stations in southern Tibet, surveyed from 2010/2011 to 2013 and corrected for secular variations, recorded up to 22.40 ± 1.11 μGal/yr of gravity increase during this period. The gravity increase is distinct from the long-wavelength secular trends of gravity decrease over the Tibetan Plateau and may be related to interseismic mass change around the locked plate interface under the Himalayan-Tibetan Plateau. We modeled the source region as a disk of 580 km in diameter, which is consistent with the notion that much of the southern Tibetan crust is involved in storing strain energy that drives the Himalayan earthquakes. If validated in other regions, high-precision ground measurements of absolute gravity may provide a useful method for monitoring mass changes in the source regions of potential large earthquakes.

The NIST Detector-Based Luminous Intensity Scale

PubMed Central

Cromer, C. L.; Eppeldauer, G.; Hardis, J. E.; Larason, T. C.; Ohno, Y.; Parr, A. C.

1996-01-01

The Système International des Unités (SI) base unit for photometry, the candela, has been realized by using absolute detectors rather than absolute sources. This change in method permits luminous intensity calibrations of standard lamps to be carried out with a relative expanded uncertainty (coverage factor k = 2, and thus a 2 standard deviation estimate) of 0.46 %, almost a factor-of-two improvement. A group of eight reference photometers has been constructed with silicon photodiodes, matched with filters to mimic the spectral luminous efficiency function for photopic vision. The wide dynamic range of the photometers aid in their calibration. The components of the photometers were carefully measured and selected to reduce the sources of error and to provide baseline data for aging studies. Periodic remeasurement of the photometers indicate that a yearly recalibration is required. The design, characterization, calibration, evaluation, and application of the photometers are discussed. PMID:27805119

Novel single photon sources for new generation of quantum communications

DTIC Science & Technology

2017-06-13

be used as building blocks for quantum cryptography and quantum key distribution There were numerous important achievements for the projects in the...single photon sources that will be used as build- ing blocks for quantum cryptography and quantum key distribution There were numerous im- portant...and enable absolutely secured information transfer between distant nodes – key prerequisite for quantum cryptography . Experiment: the experimental

Marine natural products. XXXII. Absolute configurations of C-4 of the manoalide family, biologically active sesterterpenes from the marine sponge Hyrtios erecta.

PubMed

Kobayashi, M; Okamoto, T; Hayashi, K; Yokoyama, N; Sasaki, T; Kitagawa, I

1994-02-01

Cytotoxic sesterterpenes, manoalide 25-acetals (1a, 1b), seco-manoalide (2), (E)-neomanoalide (3), (Z)-neomanoalide (4), and heteronemin (6), were isolated from the marine sponge Hyrtios erecta (collected at Amami Island, Kagoshima Prefecture, Japan) by bioassay-guided separation and the absolute configurations of these manoalide family members have been determined. Manoalide 25-acetals (1a, 1b) were shown to exhibit in vivo antitumor activity and to inhibit the DNA-relaxing activity of mouse DNA topoisomerase I and the DNA-unknotting activity of calf thymus DNA topoisomerase II.

Spatiotemporal imaging of complexity

PubMed Central

Robinson, Stephen E.; Mandell, Arnold J.; Coppola, Richard

2013-01-01

What are the functional neuroimaging measurements required for more fully characterizing the events and locations of neocortical activity? A prime assumption has been that modulation of cortical activity will inevitably be reflected in changes in energy utilization (for the most part) changes of glucose and oxygen consumption. Are such a measures complete and sufficient? More direct measures of cortical electrophysiological activity show event or task-related modulation of amplitude or band-limited oscillatory power. Using magnetoencephalography (MEG), these measures have been shown to correlate well with energy utilization sensitive BOLD fMRI. In this paper, we explore the existence of state changes in electrophysiological cortical activity that can occur independently of changes in averaged amplitude, source power or indices of metabolic rates. In addition, we demonstrate that such state changes can be described by applying a new measure of complexity, rank vector entropy (RVE), to source waveform estimates from beamformer-processed MEG. RVE is a non-parametric symbolic dynamic informational entropy measure that accommodates the wide dynamic range of measured brain signals while resolving its temporal variations. By representing the measurements by their rank values, RVE overcomes the problem of defining embedding space partitions without resorting to signal compression. This renders RVE-independent of absolute signal amplitude. In addition, this approach is robust, being relatively free of tunable parameters. We present examples of task-free and task-dependent MEG demonstrating that RVE provides new information by uncovering hidden dynamical structure in the apparent turbulent (or chaotic) dynamics of spontaneous cortical activity. PMID:23355820

Amplification and gas-dynamic parameters of the active oxygen-iodine medium produced by an ejector nozzle unit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zagidullin, M V; Nikolaev, V D; Svistun, M I

2001-08-31

The gain, the temperature, and the absolute velocity of the supersonic active oxygen-iodine medium produced by an ejector nozzle unit were determined by the technique of high-resolution diode laser spectroscopy. The gain in the active medium is formed at less than 44 mm from the nozzle unit for an absolute flow velocity {nu} {approx} 600 m s{sup -1}. Upon dilution of oxygen by primary nitrogen in the ratio of 1 : 6.9, the gain of the active medium amounts to 7x10{sup -3} cm{sup -1}, the temperature of the active medium to 200 K, the absolute flow velocity to 580 mmore » s{sup -1}, and the pressure to 58 Torr. As the dilution is increased to 1 : 13.5, the gain reduces to 4.5x10{sup -3} cm{sup -1}, the temperature lowers to 180 K, the velocity of the active medium increases to 615 m s{sup -1}, and the pressure increases to 88 Torr. The increase in the initial content of water vapour in the oxygen flow results in an increase in the temperature and a decrease in the gain of the active medium. (active media)« less

Lightning Mapping Observations During DC3 in Northern Colorado

NASA Astrophysics Data System (ADS)

Krehbiel, P. R.; Rison, W.; Thomas, R. J.

2012-12-01

The Deep Convective Clouds and Chemistry Experiment (DC3) was conducted in three regions covered by Lightning Mapping Arrays (LMAs): Oklahoma and west Texas, northern Alabama, and northern Colorado. In this and a companion presentation, we discuss results obtained from the newly-deployed North Colorado LMA. The CO LMA revealed a surprising variety of lightning-inferred electrical structures, ranging from classic tripolar, normal polarity storms to several variations of anomalously electrified systems. Storms were often characterized by a pronounced lack or deficit of cloud-to-ground discharges (negative or positive), both in relative and absolute terms compared to the large amount of intracloud activity revealed by the LMA. Anomalous electrification was observed in small, localized storms as well as in large, deeply convective and severe storms. Another surprising observation was the frequent occurrence of embedded convection in the downwind anvil/outflow region of large storm systems. Observations of discharges in low flash rate situations over or near the network are sufficiently detailed to enable branching algorithms to estimate total channel lengths for modeling NOx production. However, this will not be possible in large or distant storm systems where the lightning was essentially continuous and structurally complex, or spatially noisy. Rather, a simple empirical metric for characterizing the lightning activity can be developed based on the number of located VHF radiation sources, weighted for example by the peak source power, source altitude, and temporal duration.

Effects of energetic restriction diet on butyrylcholinesterase in obese women from southern Brazil - A longitudinal study.

PubMed

Santos, Willian Dos; Tureck, Luciane Viater; Saliba, Louise Farah; Schenknecht, Caroline Schovanz; Scaraboto, Débora; Souza, Ricardo Lehtonen R; Furtado-Alle, Lupe

2017-01-01

Butyrylcholinesterase (BChE) activity has been associated with obesity, lipid concentrations, and CHE2 locus phenotypes. This, the aim of this study was to evaluate the effects of an energetic restriction diet intervention on anthropometrical and biochemical variables and on absolute and relative BChE activity in CHE2 C5+ and CHE2 C5- individuals. One hundred eleven premenopausal obese women from Southern Brazil participated in an energetic restriction diet intervention (deficit of 2500 kJ/day) for 8 weeks. Their anthropometric and biochemical parameters were evaluated before and after the intervention. Plasma BChE activity was measured, and BChE bands in plasma and CHE2 locus phenotypes were detected by electrophoresis. The dietetic intervention decreased anthropometric and biochemical parameters as well as absolute BChE activity and relative activity of the G4 band. The CHE2 C5+ phenotype presented a different effect when compared with the CHE2 C5- phenotype. The CHE2 C5+ phenotype showed an effect in absolute BChE activity and in the relative activity of the G4 form, maintaining higher BChE activity regardless of the metabolic changes. In our study, 8 weeks was not sufficient time to lower the body mass index to normal, but it was enough to significantly reduce the absolute BChE activity, which became similar to the levels in nonobese individuals. CHE2 C5+ individuals were resistant to the decrease in BChE activity compared to CHE2 C5- individuals. This shows that the diet did not affect the CHE2 and G4 fraction complex and that the products of the CHE2 locus in association with BChE have a role in energy metabolism, maintaining high levels of enzymatic activity even after dietary intervention.

The Absolute Measurement of Beta Activities; SOBRE LA MEDIDA ABSOLUTA DE ACTIVIDADES BETA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Del Rio, C.S.; Reynaldo, O.J.; Mayquez, E.R.

1956-01-01

A new method for the absolute beta counting of solid samples is given. The measurements are made with an inside Geiger-Muller tube of new construction. The backscattering correction, when using an "infinite" thick mounting, is discussed and results for different materials given. (auth)

Perceived appraisals by others, self-esteem, and anxiety.

PubMed

Lundgren, D C; Schwab, M R

1977-11-01

Questionnaire data from 595 male and female college students were used to test four hypotheses regarding interpersonal sources of anxiety--i.e., that high anxiety occurs as a function of (a) low subjective public-esteem (perceived negative appraisals of self by others); (b) low self-esteem; (c) discrepancies where subjective public-esteem is more negative than self-esteem; and (d) absolute discrepancies between subjective public-esteem and self-esteem, regardless of evaluative direction. The results suggested that level of self-esteem and absolute discrepancies between subjective public-esteem and self-esteem are important and relatively independent factors in anxiety.

A rack-mounted precision waveguide-below-cutoff attenuator with an absolute electronic readout

NASA Technical Reports Server (NTRS)

Cook, C. C.

1974-01-01

A coaxial precision waveguide-below-cutoff attenuator is described which uses an absolute (unambiguous) electronic digital readout of displacement in inches in addition to the usual gear driven mechanical counter-dial readout in decibels. The attenuator is rack-mountable and has the input and output RF connectors in a fixed position. The attenuation rate for 55, 50, and 30 MHz operation is given along with a discussion of sources of errors. In addition, information is included to aid the user in making adjustments on the attenuator should it be damaged or disassembled for any reason.

Measurements of UV-A radiation and hazard limits from some types of outdoor lamps

NASA Astrophysics Data System (ADS)

El-Moghazy, Essam; Abd-Elmageed, Alaa-Eldin; Reda, Sameh

2015-05-01

Illumination using artificial light sources is common in these days. Many manufactures are paying for the design of lamps depending on high efficacy and low UV hazards. This research is focusing on the most useable lamps in the Egyptian markets; High Pressure Mercury (HPM), Metal Halide (MH), and High Pressure Sodium (HPS). A set up for relative spectral power distribution based on single monochromator and UVA silicon detector for absolute irradiance measurements are used. The absolute irradiance in (W/m2) in UVA region of the lamps and their accompanied standard uncertainty are evaluated.

Determination of absolute chemiluminescence quantum yields for reactions of bis-(pentachlorophenyl) oxalate, hydrogen peroxide and fluorescent compounds.

PubMed

Catherall, C L; Palmer, T F; Cundall, R B

1989-01-01

Absolute chemiluminescence quantum yields (phi CL) for reactions of bis-(pentachlorophenyl) oxalate (PCPO), hydrogen peroxide (H2O2) and 9:10 diphenyl anthracene (DPA) have been determined. A fully corrected chemiluminescence monitoring spectrometer was calibrated for spectral sensitivity using the chemiluminescence of the bis-(pentachlorophenyl) oxalate system as a liquid light source, the total photon output of which had previously been determined by chemical actinometry. At high (PCPO)/(H2O2) ratios phi CL was found to be independent of PCPO and H2O2 concentrations.

Isotope specific arbitrary material flow meter

DOEpatents

Barty, Christopher P. J.; Post, John C.; Jones, Edwin

2016-10-25

A laser-based mono-energetic gamma-ray source is used to provide non-destructive and non-intrusive, quantitative determination of the absolute amount of a specific isotope contained within pipe as part of a moving fluid or quasi-fluid material stream.

Absolute activity measurements with the windowless 4π-CsI(Tl)-sandwich spectrometer

NASA Astrophysics Data System (ADS)

Denecke, B.

1994-01-01

The windowless 4π-CsI(Tl)-sandwich spectrometer consists of two scintillation crystals sandwiching radioactive sources deposited on thin plastic foils. This configuration has a solid angle very close to 4π sr. The detectors are sensitive to charged particles with energies > 15 keV and measure photons of 15-200 keV with a probability > 98%. Disintegration rates of samples of radionuclides with complex decay modes can be determined directly from the measured count rates with uncertainties below 0.3%. Radionuclide solutions of 57Co, 109Cd, 125I, 152Eu and 192Ir were standardised, partly in the framework of international comparisons. A detailed description of the spectrometer and the measurement procedure is given.

Effect of essential oil and supercritical carbon dioxide extract from the root of Angelica gigas on human EEG activity.

PubMed

Sowndhararajan, Kandhasamy; Seo, Min; Kim, Minju; Kim, Heeyeon; Kim, Songmun

2017-08-01

The present study aimed to investigate the effect of inhalation of essential oil (EO) and supercritical carbon dioxide extract (SC-CO 2 ) from the root of A. gigas on human electroencephalographic (EEG) activity. For this purpose, the EO was obtained from the root of A. gigas by steam distillation and SC-CO 2 was obtained at 50 °C and 400 bar for 1 h. The EEG readings were recorded using the QEEG-8 system from 8 electrode sites according to the International 10-20 system. In the EEG study, the absolute low beta (left temporal and left parietal) activity significantly increased during the inhalation of EO. In the case of SC-CO 2 inhalation, there was no significant change in absolute waves. The results revealed that the EO of A. gigas root produced significant changes in the absolute low beta activity and these changes may enhance the language learning abilities of human brain. Copyright © 2017. Published by Elsevier Ltd.

Absolute calibration of the Agfa Structurix series films at energies between 2.7 and 6.2 keV.

PubMed

Lanier, N E; Cowan, J S

2014-11-01

Although photo-emulsion technology is many decades old, x-ray film still remains a key asset for diagnosing hydrodynamic features in High-Energy Density (HED) experiments. For decades, the preferred option had been Kodak's direct exposure film. After its discontinuance in 2004, the push to find alternatives began. In many situations, the Agfa Structurix series offers the most favorable substitute, but being new to the HED community, its characterization was lacking. To remedy this, recent experiments, conducted at Brookhaven's National Synchrotron Light Source, provide absolute, monochromatic calibration data for the Agfa Structurix series films at K-shell backlighter energies between 2.7 and 6.2 keV. Absolute response curves are presented for Agfa D8, D7, D4, D4sc, D3, and D2. Moreover, the transmission of each film type is also measured.

Absolute sensitivity calibration of an extreme ultraviolet spectrometer for tokamak measurements

NASA Astrophysics Data System (ADS)

Guirlet, R.; Schwob, J. L.; Meyer, O.; Vartanian, S.

2017-01-01

An extreme ultraviolet spectrometer installed on the Tore Supra tokamak has been calibrated in absolute units of brightness in the range 10-340 Å. This has been performed by means of a combination of techniques. The range 10-113 Å was absolutely calibrated by using an ultrasoft-X ray source emitting six spectral lines in this range. The calibration transfer to the range 113-182 Å was performed using the spectral line intensity branching ratio method. The range 182-340 Å was calibrated thanks to radiative-collisional modelling of spectral line intensity ratios. The maximum sensitivity of the spectrometer was found to lie around 100 Å. Around this wavelength, the sensitivity is fairly flat in a 80 Å wide interval. The spatial variations of sensitivity along the detector assembly were also measured. The observed trend is related to the quantum efficiency decrease as the angle of the incoming photon trajectories becomes more grazing.

Absolute calibration of the Agfa Structurix series films at energies between 2.7 and 6.2 keVa)

NASA Astrophysics Data System (ADS)

Lanier, N. E.; Cowan, J. S.

2014-11-01

Although photo-emulsion technology is many decades old, x-ray film still remains a key asset for diagnosing hydrodynamic features in High-Energy Density (HED) experiments. For decades, the preferred option had been Kodak's direct exposure film. After its discontinuance in 2004, the push to find alternatives began. In many situations, the Agfa Structurix series offers the most favorable substitute, but being new to the HED community, its characterization was lacking. To remedy this, recent experiments, conducted at Brookhaven's National Synchrotron Light Source, provide absolute, monochromatic calibration data for the Agfa Structurix series films at K-shell backlighter energies between 2.7 and 6.2 keV. Absolute response curves are presented for Agfa D8, D7, D4, D4sc, D3, and D2. Moreover, the transmission of each film type is also measured.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patankar, S.; Gumbrell, E. T.; Robinson, T. S.

Here we report a new method using high stability, laser-driven supercontinuum generation in a liquid cell to calibrate the absolute photon response of fast optical streak cameras as a function of wavelength when operating at fastest sweep speeds. A stable, pulsed white light source based around the use of self-phase modulation in a salt solution was developed to provide the required brightness on picosecond timescales, enabling streak camera calibration in fully dynamic operation. The measured spectral brightness allowed for absolute photon response calibration over a broad spectral range (425-650nm). Calibrations performed with two Axis Photonique streak cameras using the Photonismore » P820PSU streak tube demonstrated responses which qualitatively follow the photocathode response. Peak sensitivities were 1 photon/count above background. The absolute dynamic sensitivity is less than the static by up to an order of magnitude. We attribute this to the dynamic response of the phosphor being lower.« less

Determination of absolute configuration in 4-aryl-3, 4-dihydro-2(1H)-pyrimidones by high performance liquid chromatography and CD spectroscopy.

PubMed

Krenn, W; Verdino, P; Uray, G; Faber, K; Kappe, C O

1999-01-01

The absolute configuration of three 4-aryl-3, 4-dihydro-2(1H)-pyrimidones (Biginelli compounds, DHPMs) was established by comparison of the typical circular dichroism (CD) spectra of individual enantiomers with reference samples of known absolute configuration. The enantiomers were obtained by semipreparative separation of racemic mixtures on a Chiralcel OD-H chiral stationary phase. The method was used to establish the enantiopreference of various lipases in biocatalytic kinetic resolution experiments employing activated DHPM esters. Copyright 1999 Wiley-Liss, Inc.

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Science.gov Websites

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Identification of Active Galactic Nuclei through HST optical variability in the GOODS South field

NASA Astrophysics Data System (ADS)

Pouliasis, Ektoras; Georgantopoulos; Bonanos, A.; HCV Team

2016-08-01

This work aims to identify AGN in the GOODS South deep field through optical variability. This method can easily identify low-luminosity AGN. In particular, we use images in the z-band obtained from the Hubble Space Telescope with the ACS/WFC camera over 5 epochs separated by ~45 days. Aperture photometry has been performed using SExtractor to extract the lightcurves. Several variability indices, such as the median absolute deviation, excess variance, and sigma were applied to automatically identify the variable sources. After removing artifacts, stars and supernovae from the variable selected sample and keeping only those sources with known photometric or spectroscopic redshift, the optical variability was compared to variability in other wavelengths (X-rays, mid-IR, radio). This multi-wavelength study provides important constraints on the structure and the properties of the AGN and their relation to their hosts. This work is a part of the validation of the Hubble Catalog of Variables (HCV) project, which has been launched at the National Observatory of Athens by ESA, and aims to identify all sources (pointlike and extended) showing variability, based on the Hubble Source Catalog (HSC, Whitmore et al. 2015). The HSC version 1 was released in February 2015 and includes 80 million sources imaged with the WFPC2, ACS/WFC, WFC3/UVIS and WFC3/IR cameras.

Advances in the Metrology of Absolute Value Assignments to Isotopic Reference Materials: Consequences from the Avogadro Project

NASA Astrophysics Data System (ADS)

Vocke, Robert; Rabb, Savelas

2015-04-01

All isotope amount ratios (hereafter referred to as isotope ratios) produced and measured on any mass spectrometer are biased. This unfortunate situation results mainly from the physical processes in the source area where ions are produced. Because the ionized atoms in poly-isotopic elements have different masses, such processes are typically mass dependent and lead to what is commonly referred to as mass fractionation (for thermal ionization and electron impact sources) and mass bias (for inductively coupled plasma sources.) This biasing process produces a measured isotope ratio that is either larger or smaller than the "true" ratio in the sample. This has led to the development of numerous fractionation "laws" that seek to correct for these effects, many of which are not based on the physical processes giving rise to the biases. The search for tighter and reproducible precisions has led to two isotope ratio measurement systems that exist side-by-side. One still seeks to measure "absolute" isotope ratios while the other utilizes an artifact based measurement system called a delta-scale. The common element between these two measurement systems is the utilization of isotope reference materials (iRMs). These iRMs are used to validate a fractionation "law" in the former case and function as a scale anchor in the latter. Many value assignments of iRMs are based on "best measurements" by the original groups producing the reference material, a not entirely satisfactory approach. Other iRMs, with absolute isotope ratio values, have been produced by calibrated measurements following the Atomic Weight approach (AW) pioneered by NBS nearly 50 years ago. Unfortunately, the AW is not capable of calibrating the new generation of iRMs to sufficient precision. So how do we get iRMs with isotope ratios of sufficient precision and without bias? Such a focus is not to denigrate the extremely precise delta-scale measurements presently being made on non-traditional and tradition stable isotope systems. But even absolute isotope ratio measurements have an important role to play in delta-scale schemes. Highly precise and unbiased measurements of the artifact anchor for any scale facilitates the replacement of that scale's anchor once the initial supply of the iRM is exhausted. Absolute isotope ratio measurements of artifacts at the positive and negative extremes of a delta-scale will allow the appropriate assignment of delta-values to these normalizing iRMs, thereby minimizing any scale contractions or expansions to either side of the anchor artifact. And finally, absolute values for critical iRMs with also allow delta-scale results to be used in other scientific disciplines that employ other units of measure. Precise absolute isotope ratios of Si has been one of the consequences of the Avogadro Project (an international effort to replace the original kilogram artifact with a natural constant, the Planck constant.) We will present the results of applying such measurements to the principal iRMs for the Si isotope system (SRM 990, Big Batch and Diatomite) and its consequences for their delta-Si29 and delta-Si30 values.

Localised excitation of a single photon source by a nanowaveguide.

PubMed

Geng, Wei; Manceau, Mathieu; Rahbany, Nancy; Sallet, Vincent; De Vittorio, Massimo; Carbone, Luigi; Glorieux, Quentin; Bramati, Alberto; Couteau, Christophe

2016-01-29

Nowadays, integrated photonics is a key technology in quantum information processing (QIP) but achieving all-optical buses for quantum networks with efficient integration of single photon emitters remains a challenge. Photonic crystals and cavities are good candidates but do not tackle how to effectively address a nanoscale emitter. Using a nanowire nanowaveguide, we realise an hybrid nanodevice which locally excites a single photon source (SPS). The nanowire acts as a passive or active sub-wavelength waveguide to excite the quantum emitter. Our results show that localised excitation of a SPS is possible and is compared with free-space excitation. Our proof of principle experiment presents an absolute addressing efficiency ηa ~ 10(-4) only ~50% lower than the one using free-space optics. This important step demonstrates that sufficient guided light in a nanowaveguide made of a semiconductor nanowire is achievable to excite a single photon source. We accomplish a hybrid system offering great potentials for electrically driven SPSs and efficient single photon collection and detection, opening the way for optimum absorption/emission of nanoscale emitters. We also discuss how to improve the addressing efficiency of a dipolar nanoscale emitter with our system.

Localised excitation of a single photon source by a nanowaveguide

PubMed Central

Geng, Wei; Manceau, Mathieu; Rahbany, Nancy; Sallet, Vincent; De Vittorio, Massimo; Carbone, Luigi; Glorieux, Quentin; Bramati, Alberto; Couteau, Christophe

2016-01-01

Nowadays, integrated photonics is a key technology in quantum information processing (QIP) but achieving all-optical buses for quantum networks with efficient integration of single photon emitters remains a challenge. Photonic crystals and cavities are good candidates but do not tackle how to effectively address a nanoscale emitter. Using a nanowire nanowaveguide, we realise an hybrid nanodevice which locally excites a single photon source (SPS). The nanowire acts as a passive or active sub-wavelength waveguide to excite the quantum emitter. Our results show that localised excitation of a SPS is possible and is compared with free-space excitation. Our proof of principle experiment presents an absolute addressing efficiency ηa ~ 10−4 only ~50% lower than the one using free-space optics. This important step demonstrates that sufficient guided light in a nanowaveguide made of a semiconductor nanowire is achievable to excite a single photon source. We accomplish a hybrid system offering great potentials for electrically driven SPSs and efficient single photon collection and detection, opening the way for optimum absorption/emission of nanoscale emitters. We also discuss how to improve the addressing efficiency of a dipolar nanoscale emitter with our system. PMID:26822999

Changing Conceptions of Activation Energy.

ERIC Educational Resources Information Center

Pacey, Philip D.

1981-01-01

Provides background material which relates to the concept of activation energy, fundamental in the study of chemical kinetics. Compares the related concepts of the Arrhenius activation energy, the activation energy at absolute zero, the enthalpy of activation, and the threshold energy. (CS)

Non-destructive method for determining neutron exposure and constituent concentrations of a body

DOEpatents

Gold, Raymond; McElroy, William N.

1986-01-01

A non-destructive method for determination of neutron exposure and constituent concentrations in an object, such as reactor pressure vessel, is based on the observation of characteristic gamma-rays emitted by activation products in the object by using a unique continuous gamma-ray spectrometer. The spectrometer views the object through appropriate collimators to determine the absolute emission rate of these characteristic gamma-rays, thereby ascertaining the absolute activity of given activation products in the object. These data can then be used to deduce the spatial and angular dependence of neutron exposure or the spatial constituent concentration at regions of interest within the object.

Non-destructive method for determining neutron exposure and constituent concentrations of a body

DOEpatents

Gold, R.; McElroy, W.N.

1984-02-22

A non-destructive method for determination of neutron exposure and constituent concentrations in an object, such as a reactor pressure vessel, is based on the observation of characteristic gamma-rays emitted by activation products in the object by using a unique continuous gamma-ray spectrometer. The spectrometer views the object through appropriate collimators to determine the absolute emission rate of these characteristic gamma-rays, thereby ascertaining the absolute activity of given activation products in the object. These data can then be used to deduce the spatial and angular dependence of neutron exposure or the spatial constituent concentrations at regions of interest within the object.

Vacuum ultraviolet photoionization cross section of the hydroxyl radical.

PubMed

Dodson, Leah G; Savee, John D; Gozem, Samer; Shen, Linhan; Krylov, Anna I; Taatjes, Craig A; Osborn, David L; Okumura, Mitchio

2018-05-14

The absolute photoionization spectrum of the hydroxyl (OH) radical from 12.513 to 14.213 eV was measured by multiplexed photoionization mass spectrometry with time-resolved radical kinetics. Tunable vacuum ultraviolet (VUV) synchrotron radiation was generated at the Advanced Light Source. OH radicals were generated from the reaction of O( 1 D) + H 2 O in a flow reactor in He at 8 Torr. The initial O( 1 D) concentration, where the atom was formed by pulsed laser photolysis of ozone, was determined from the measured depletion of a known concentration of ozone. Concentrations of OH and O( 3 P) were obtained by fitting observed time traces with a kinetics model constructed with literature rate coefficients. The absolute cross section of OH was determined to be σ(13.436 eV) = 3.2 ± 1.0 Mb and σ(14.193 eV) = 4.7 ± 1.6 Mb relative to the known cross section for O( 3 P) at 14.193 eV. The absolute photoionization spectrum was obtained by recording a spectrum at a resolution of 8 meV (50 meV steps) and scaling to the single-energy cross sections. We computed the absolute VUV photoionization spectrum of OH and O( 3 P) using equation-of-motion coupled-cluster Dyson orbitals and a Coulomb photoelectron wave function and found good agreement with the observed absolute photoionization spectra.

Vacuum ultraviolet photoionization cross section of the hydroxyl radical

NASA Astrophysics Data System (ADS)

Dodson, Leah G.; Savee, John D.; Gozem, Samer; Shen, Linhan; Krylov, Anna I.; Taatjes, Craig A.; Osborn, David L.; Okumura, Mitchio

2018-05-01

The absolute photoionization spectrum of the hydroxyl (OH) radical from 12.513 to 14.213 eV was measured by multiplexed photoionization mass spectrometry with time-resolved radical kinetics. Tunable vacuum ultraviolet (VUV) synchrotron radiation was generated at the Advanced Light Source. OH radicals were generated from the reaction of O(1D) + H2O in a flow reactor in He at 8 Torr. The initial O(1D) concentration, where the atom was formed by pulsed laser photolysis of ozone, was determined from the measured depletion of a known concentration of ozone. Concentrations of OH and O(3P) were obtained by fitting observed time traces with a kinetics model constructed with literature rate coefficients. The absolute cross section of OH was determined to be σ(13.436 eV) = 3.2 ± 1.0 Mb and σ(14.193 eV) = 4.7 ± 1.6 Mb relative to the known cross section for O(3P) at 14.193 eV. The absolute photoionization spectrum was obtained by recording a spectrum at a resolution of 8 meV (50 meV steps) and scaling to the single-energy cross sections. We computed the absolute VUV photoionization spectrum of OH and O(3P) using equation-of-motion coupled-cluster Dyson orbitals and a Coulomb photoelectron wave function and found good agreement with the observed absolute photoionization spectra.

Analysis of standard reference materials by absolute INAA

NASA Astrophysics Data System (ADS)

Heft, R. E.; Koszykowski, R. F.

1981-07-01

Three standard reference materials: flyash, soil, and ASI 4340 steel, are analyzed by a method of absolute instrumental neutron activation analysis. Two different light water pool-type reactors were used to produce equivalent analytical results even though the epithermal to thermal flux ratio in one reactor was higher than that in the other by a factor of two.

Directional responding of C57BL/6J mice in the Morris water maze is influenced by visual and vestibular cues and is dependent upon the anterior thalamic nuclei

PubMed Central

Stackman, Robert W.; Lora, Joan C.; Williams, Sidney B.

2012-01-01

Recent findings indicate that rats navigate in spatial tasks such as the Morris water maze (MWM) using a local cue-based reference frame rather than a distal cue-based reference frame. Specifically, rats swim in a particular direction to a location relative to pool-based cues, rather than to an absolute location defined by room-based cues. Neural mechanisms supporting this bias in rodents for relative responding in spatial tasks are not yet understood. Anterior thalamic neurons discharge according to the current directional heading of the animal. The contribution of head direction (HD) cell activity to navigation has been difficult to elucidate. We found that male C57BL/6J mice trained for 4 or 7 days in the MWM exhibited an overwhelming preference for swimming in a direction relative to pool-based cues over absolute responding during a platform-less probe test. Rotation of extra-maze cues caused a corresponding rotation of the direction mice swam during probe test, suggesting that both pool- and room-based reference frames guide platform search. However, disorienting the mice before the probe test disturbed relative responding. Therefore, relative responding is guided by both internal and external cue sources. Selective inactivation of anterior thalamic nuclei (ATN) by microinfusion of muscimol or fluorophore-conjugated muscimol caused a near complete shift in preference from relative to absolute responding. Interestingly, inactivation of the dorsal CA1 region of the hippocampus did not affect relative responding. These data suggest that ATN, and HD cells therein, may guide relative responding in the MWM, a task considered by most to reflect hippocampal processing. PMID:22836256

Is there a Stobbs factor in atomic-resolution STEM-EELS mapping?

PubMed

Xin, Huolin L; Dwyer, Christian; Muller, David A

2014-04-01

Recent work has convincingly argued that the Stobbs factor-disagreement in contrast between simulated and experimental atomic-resolution images-in ADF-STEM imaging can be accounted for by including the incoherent source size in simulation. However, less progress has been made for atomic-resolution STEM-EELS mapping. Here we have performed carefully calibrated EELS mapping experiments of a [101] DyScO3 single-crystal specimen, allowing atomic-resolution EELS signals to be extracted on an absolute scale for a large range of thicknesses. By simultaneously recording the elastic signal, also on an absolute scale, and using it to characterize the source size, sample thickness and inelastic mean free path, we eliminate all free parameters in the simulation of the core-loss signals. Coupled with double channeling simulations that incorporate both core-loss inelastic scattering and dynamical elastic and thermal diffuse scattering, the present work enables a close scrutiny of the scattering physics in the inelastic channel. We found that by taking into account the effective source distribution determined from the ADF images, both the absolute signal and the contrast in atomic-resolution Dy-M5 maps can be closely reproduced by the double-channeling simulations. At lower energy losses, discrepancies are present in the Sc-L2,3 and Dy-N4,5 maps due to the energy-dependent spatial distribution of the background spectrum, core-hole effects, and omitted complexities in the final states. This work has demonstrated the possibility of using quantitative STEM-EELS for element-specific column-by-column atom counting at higher energy losses and for atomic-like final states, and has elucidated several possible improvements for future theoretical work. Copyright © 2014 Elsevier B.V. All rights reserved.

Statistical study of interplanetary condition effect on geomagnetic storms: 2. Variations of parameters

NASA Astrophysics Data System (ADS)

Yermolaev, Yu. I.; Lodkina, I. G.; Nikolaeva, N. S.; Yermolaev, M. Yu.

2011-02-01

We investigate the behavior of mean values of the solar wind’s and interplanetary magnetic field’s (IMF) parameters and their absolute and relative variations during the magnetic storms generated by various types of the solar wind. In this paper, which is a continuation of paper [1], we, on the basis of the OMNI data archive for the period of 1976-2000, have analyzed 798 geomagnetic storms with D st ≤ -50 nT and their interplanetary sources: corotating interaction regions CIR, compression regions Sheath before the interplanetary CMEs; magnetic clouds MC; “Pistons” Ejecta, and an uncertain type of a source. For the analysis the double superposed epoch analysis method was used, in which the instants of the magnetic storm onset and the minimum of the D st index were taken as reference times. It is shown that the set of interplanetary sources of magnetic storms can be sub-divided into two basic groups according to their slowly and fast varying characteristics: (1) ICME (MC and Ejecta) and (2) CIR and Sheath. The mean values, the absolute and relative variations in MC and Ejecta for all parameters appeared to be either mean or lower than the mean value (the mean values of the electric field E y and of the B z component of IMF are higher in absolute value), while in CIR and Sheath they are higher than the mean value. High values of the relative density variation sN/< N> are observed in MC. At the same time, the high values for relative variations of the velocity, B z component, and IMF magnitude are observed in Sheath and CIR. No noticeable distinctions in the relationships between considered parameters for moderate and strong magnetic storms were observed.

Characteristics of ultrasonic acoustic emissions from walnut branches during freeze-thaw-induced embolism formation.

PubMed

Kasuga, Jun; Charrier, Guillaume; Uemura, Matsuo; Améglio, Thierry

2015-04-01

Ultrasonic acoustic emission (UAE) methods have been applied for the detection of freeze-thaw-induced embolism formation in water conduits of tree species. Until now, however, the exact source(s) of UAE has not been identified especially in angiosperm species, in which xylem tissues are composed of diverse types of cells. In this study, UAE was recorded from excised branches of walnut (Juglans regia cv. Franquette) during freeze-thaw cycles, and attempts were made to characterize UAEs generated by cavitation events leading to embolism formation according to their properties. During freeze-thaw cycles, a large number of UAEs were generated from the sample segments. However, the cumulative numbers of total UAE during freeze-thawing were not correlated with the percentage loss of hydraulic conductivity after thawing, suggesting that the sources of UAE were not only cavitation leading to embolism formation in vessels. Among the UAEs, cumulative numbers of UAEs with absolute energy >10.0 fJ strongly correlated with the increase in percentage loss of hydraulic conductivity. The high absolute energy of the UAEs might reflect the formation of large bubbles in the large lumen of vessels. Therefore, UAEs generated by cavitation events in vessels during freeze-thawing might be distinguished from other signals according to their magnitudes of absolute energy. On the other hand, the freezing of xylem parenchyma cells was followed by a certain number of UAEs. These results indicate the possibility that UAE methods can be applied to the detection of both freeze-thaw-induced embolism and supercooling breakdown in parenchyma cells in xylem. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Analysis of sewage sludge using an experimental prompt gamma neutron activation analysis (pgnaa) set-up with an am-be source

NASA Astrophysics Data System (ADS)

Idiri, Z.; Redjem, F.; Beloudah, N.

2016-09-01

An experimental PGNAA set-up using a 1 Ci Am-Be source has been developed and used for analysis of bulk sewage sludge samples issued from a wastewater treatment plant situated in an industrial area of Algiers. The sample dimensions were optimized using thermal neutron flux calculations carried out with the MCNP5 Monte Carlo Code. A methodology is then proposed to perform quantitative analysis using the absolute method. For this, average thermal neutron flux inside the sludge samples is deduced using average thermal neutron flux in reference water samples and thermal flux measurements with the aid of a 3He neutron detector. The average absolute gamma detection efficiency is determined using the prompt gammas emitted by chlorine dissolved in a water sample. The gamma detection efficiency is normalized for sludge samples using gamma attenuation factors calculated with the MCNP5 code for water and sludge. Wet and dehydrated sludge samples were analyzed. Nutritive elements (Ca, N, P, K) and heavy metals elements like Cr and Mn were determined. For some elements, the PGNAA values were compared to those obtained using Atomic Absorption Spectroscopy (AAS) and Inductively Coupled Plasma (ICP) methods. Good agreement is observed between the different values. Heavy element concentrations are very high compared to normal values; this is related to the fact that the wastewater treatment plant is treating not only domestic but also industrial wastewater that is probably rejected by industries without removal of pollutant elements. The detection limits for almost all elements of interest are sufficiently low for the method to be well suited for such analysis.

Absolute cross sections of the 86Sr(α,n)89Zr reaction at energies of astrophysical interest

NASA Astrophysics Data System (ADS)

Oprea, Andreea; Glodariu, Tudor; Filipescu, Dan; Gheorghe, Ioana; Mitu, Andreea; Boromiza, Marian; Bucurescu, Dorel; Costache, Cristian; Cata-Danil, Irina; Florea, Nicoleta; Ghita, Dan Gabriel; Ionescu, Alina; Marginean, Nicolae; Marginean, Raluca; Mihai, Constantin; Mihai, Radu; Negret, Alexandru; Nita, Cristina; Olacel, Adina; Pascu, Sorin; Sotty, Cristophe; Suvaila, Rares; Stan, Lucian; Stroe, Lucian; Serban, Andreea; Stiru, Irina; Toma, Sebastian; Turturica, Andrei; Ujeniuc, Sorin

2017-09-01

Absolute cross sections for the 86Sr(α,n)89Zr reaction at energies close to the Gamow window are reported. Three thin SrF2 targets were irradiated using the 9 MV Tandem facility in IFIN-HH Bucharest that delivered α beams for the activation process. Two high-purity Germanium detectors were used to measure the induced activity of 89Zr in a low background environment. The experimental results are in very good agreement with Hauser-Feshbach statistical model calculations performed with the TALYS code.

Electromagnetic waves with frequencies near the local proton gyrofrequency: ISEE-3 1 AU observations

NASA Technical Reports Server (NTRS)

Tsurutani, Bruce T.; Arballo, John K.; Mok, John; Smith, Edward J.; Mason, Glenn M.; Tan, Lun C.

1994-01-01

Low Frequency (LF) electromagnetic waves with periods near the local proton gyrofrequency have been detected in interplanetary space by the magnetometer onboard International-Sun-Earth-Explorer-3 (ISEE-3). Transverse peak-to-peak amplitudes as large as delta vector B/absolute value of B approximately 0.4 have been noted with compressional components (Delta absolute value of B/absolute value of B) typically less than or = 0.1. Generally, the waves have even smaller amplitudes, or are not detectable within the solar wind turbulence. The waves are elliptically/linearly polarized and are often, but not always, found to propagate nearly along vector B(sub zero). Both right- and left-hand polarizations in the spacecraft-frame have been detected. The waves are observed during all orientations of the interplanetary magnetic field, with the Parker spiral orientation being the most common case. Because the waves are detected at and near the local proton cyclotron frequency, the generation mechanism must almost certainly be solar wind pickup of freshly created hydrogen ions. Possible sources for the hydrogen are the Earth's atmosphere, coronal mass ejections from the Sun, comets and interstellar neutral atoms. At this time it is not obvious which potential source is the correct one. Statistical tests employing over one year of ISEE-3 data will be done in the near future to eliminate/confirm some of these possibilities.

Towards an Absolute Chronology for the Aegean Iron Age: New Radiocarbon Dates from Lefkandi, Kalapodi and Corinth

PubMed Central

Toffolo, Michael B.; Fantalkin, Alexander; Lemos, Irene S.; Felsch, Rainer C. S.; Niemeier, Wolf-Dietrich; Sanders, Guy D. R.; Finkelstein, Israel; Boaretto, Elisabetta

2013-01-01

The relative chronology of the Aegean Iron Age is robust. It is based on minute stylistic changes in the Submycenaean, Protogeometric and Geometric styles and their sub-phases. Yet, the absolute chronology of the time-span between the final stages of Late Helladic IIIC in the late second millennium BCE and the archaic colonization of Italy and Sicily toward the end of the 8th century BCE lacks archaeological contexts that can be directly related to events carrying absolute dates mentioned in Egyptian/Near Eastern historical sources, or to well-dated Egyptian/Near Eastern rulers. The small number of radiocarbon dates available for this time span is not sufficient to establish an absolute chronological sequence. Here we present a new set of short-lived radiocarbon dates from the sites of Lefkandi, Kalapodi and Corinth in Greece. We focus on the crucial transition from the Submycenaean to the Protogeometric periods. This transition is placed in the late 11th century BCE according to the Conventional Aegean Chronology and in the late 12th century BCE according to the High Aegean Chronology. Our results place it in the second half of the 11th century BCE. PMID:24386150

Depth-encoded dual beam phase-resolved Doppler OCT for Doppler-angle-independent flow velocity measurement

NASA Astrophysics Data System (ADS)

Qian, Jie; Cheng, Wei; Cao, Zhaoyuan; Chen, Xinjian; Mo, Jianhua

2017-02-01

Phase-resolved Doppler optical coherence tomography (PR-D-OCT) is a functional OCT imaging technique that can provide high-speed and high-resolution depth-resolved measurement on flow in biological materials. However, a common problem with conventional PR-D-OCT is that this technique often measures the flow motion projected onto the OCT beam path. In other words, it needs the projection angle to extract the absolute velocity from PR-D-OCT measurement. In this paper, we proposed a novel dual-beam PR-D-OCT method to measure absolute flow velocity without separate measurement on the projection angle. Two parallel light beams are created in sample arm and focused into the sample at two different incident angles. The images produced by these two beams are encoded to different depths in single B-scan. Then the Doppler signals picked up by the two beams together with the incident angle difference can be used to calculate the absolute velocity. We validated our approach in vitro on an artificial flow phantom with our home-built 1060 nm swept source OCT. Experimental results demonstrated that our method can provide an accurate measurement of absolute flow velocity with independency on the projection angle.

Quantification of intensity variations in functional MR images using rotated principal components

NASA Astrophysics Data System (ADS)

Backfrieder, W.; Baumgartner, R.; Sámal, M.; Moser, E.; Bergmann, H.

1996-08-01

In functional MRI (fMRI), the changes in cerebral haemodynamics related to stimulated neural brain activity are measured using standard clinical MR equipment. Small intensity variations in fMRI data have to be detected and distinguished from non-neural effects by careful image analysis. Based on multivariate statistics we describe an algorithm involving oblique rotation of the most significant principal components for an estimation of the temporal and spatial distribution of the stimulated neural activity over the whole image matrix. This algorithm takes advantage of strong local signal variations. A mathematical phantom was designed to generate simulated data for the evaluation of the method. In simulation experiments, the potential of the method to quantify small intensity changes, especially when processing data sets containing multiple sources of signal variations, was demonstrated. In vivo fMRI data collected in both visual and motor stimulation experiments were analysed, showing a proper location of the activated cortical regions within well known neural centres and an accurate extraction of the activation time profile. The suggested method yields accurate absolute quantification of in vivo brain activity without the need of extensive prior knowledge and user interaction.

Desmopressin therapy to assist the functional identification and characterisation of von Willebrand disease: differential utility from combining two (VWF:CB and VWF:RCo) von Willebrand factor activity assays?

PubMed

Favaloro, Emmanuel J; Thom, Jim; Patterson, David; Just, Sarah; Dixon, Tracy; Koutts, Jerry; Baccala, Maria; Rowell, John; Baker, Ross

2009-04-01

We performed a retrospective audit of desmopressin (DDAVP) usage to assist in the functional characterisation of von Willebrand disease (VWD). Data was evaluated for 208 patients, comprising those with VWD (Type 1 [n=160], Type 2A [n=19], Type 2M [n=10]), plus 19 individuals with haemophilia or carriers of haemophilia. Laboratory testing comprised pre- and post-DDAVP evaluation of factor VIII (FVIII:C), von Willebrand factor (VWF) antigen (VWF:Ag), VWF ristocetin cofactor (VWF:RCo) activity, VWF collagen binding (VWF:CB) activity, and in one laboratory an alternate VWF activity assay. In brief, combined usage of VWF:RCo and VWF:CB appears to provide improved functional characterisation and/or 'classification' of VWD types, in particular better differentiation of Type 2A and 2M VWD, and clearer validation of a Type 1 VWD diagnosis. Thus, (i) Type 1 VWD displayed generally good absolute and relative rises in all test parameters, although relative rises were greatest for FVIII:C and VWF:CB, and CB/Ag ratio increases overshadowed those for RCo/Ag; (ii) Type 2A VWD patients showed good absolute and relative rises in both FVIII:C and VWF:Ag, but poor absolute rises in both VWF:CB and VWF:RCo; although small rises in both CB/Ag and RCo/Ag were also observed, both ratios tended to remain below 0.7; (iii) finally, Type 2 M VWD patients generally showed good absolute and relative rises in FVIII:C, VWF:Ag and VWF:CB, but a poor absolute and relative rise in VWF:RCo; thus, there were good rises in CB/Ag ratios but little change in RCo/Ag, which tended to remain below 0.7. Future multi-centre prospective investigations are warranted to validate these findings and to investigate their therapeutic implications.

Immunomodulatory constituents from an Ascomycete, Eupenicillium crustaceum, and revised absolute structure of macrophorin D.

PubMed

Fujimoto, H; Nakamura, E; Kim, Y P; Okuyama, E; Ishibashi, M; Sassa, T

2001-09-01

Fractionation guided by immunomodulatory activity of the EtOAc extract of the Ascomycete Eupenicillium crustaceum has afforded two new naturally occurring products, 4'-oxomacrophorin D (1) and 4'-oxomacrophorin A (2), as the immunosuppressive components of this fungus [1: 3-hydroxy-3-methylglutaryl (HMG) conjugate of 2]. The structures including the absolute configurations of 1 and 2 have been determined on the basis of chemical correlation of 1 with macrophorin D (3). The absolute configuration of the HMG moiety in 3 has been revised from 3R to 3S.

Neutron skyshine measurements at Fermilab.

PubMed

Cossairt, J D; Coulson, L V

1985-02-01

Neutron skyshine has been a significant source of environmental radiation exposure at many high-energy proton accelerators. A particularly troublesome source of skyshine neutrons has existed at Fermilab during operation of the 400-GeV high-energy physics program. This paper reports on several measurements of this source made with a DePangher precision long counter at large distances. The spatial distribution of the neutron skyshine can approximately be described as an inverse square law dependence multiplied by an exponential with an approximate attenuation length of 1200 +/- 300 m. The absolute magnitude of the distributions can be matched directly to the conventionally measured absorbed dose distribution near the source.

Reliability of quantitative EEG (qEEG) measures and LORETA current source density at 30 days.

PubMed

Cannon, Rex L; Baldwin, Debora R; Shaw, Tiffany L; Diloreto, Dominic J; Phillips, Sherman M; Scruggs, Annie M; Riehl, Timothy C

2012-06-14

There is a growing interest for using quantitative EEG and LORETA current source density in clinical and research settings. Importantly, if these indices are to be employed in clinical settings then the reliability of these measures is of great concern. Neuroguide (Applied Neurosciences) is sophisticated software developed for the analyses of power, and connectivity measures of the EEG as well as LORETA current source density. To date there are relatively few data evaluating topographical EEG reliability contrasts for all 19 channels and no studies have evaluated reliability for LORETA calculations. We obtained 4 min eyes-closed and eyes-opened EEG recordings at 30-day intervals. The EEG was analyzed in Neuroguide and FFT power, coherence and phase was computed for traditional frequency bands (delta, theta, alpha and beta) and LORETA current source density was calculated in 1 Hz increments and summed for total power in eight regions of interest (ROI). In order to obtain a robust measure of reliability we utilized a random effects model with an absolute agreement definition. The results show very good reproducibility for total absolute power and coherence. Phase shows lower reliability coefficients. LORETA current source density shows very good reliability with an average 0.81 for ECB and 0.82 for EOB. Similarly, the eight regions of interest show good to very good agreement across time. Implications for future directions and use of qEEG and LORETA in clinical populations are discussed. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

44 CFR 67.6 - Basis of appeal.

Code of Federal Regulations, 2010 CFR

2010-10-01

... absolute (except where mathematical or measurement error or changed physical conditions can be demonstrated... a mathematical or measurement error or changed physical conditions, then the specific source of the... registered professional engineer or licensed land surveyor, of the new data necessary for FEMA to conduct a...

48 CFR 932.7003 - Policies.

Code of Federal Regulations, 2010 CFR

2010-10-01

... contract has been awarded as a result of competitive bidding should not, of itself, render the loan... that the materials or services to be provided cannot readily be acquired from alternative sources does not require the finding that the materials or services are absolutely unobtainable elsewhere. The...

Absolute Effective Area of the Chandra High-Resolution Mirror Assembly

NASA Technical Reports Server (NTRS)

Schwartz, D. A.; David, L. P.; Donnelly, R. H.; Edgar, R. J.; Gaetz, T. J.; Jerius, D.; Juda, M.; Kellogg, E. M.; McNamara, B. R.; Dewey, D.

2000-01-01

The Chandra X-ray Observatory was launched in July 1999, and is returning exquisite sub-arcsecond x-ray images of star groups, supernova remnants, galaxies, quasars, and clusters of galaxies. In addition to being the premier X-ray observatory in terms of angular and spectral resolution, Chandra is the best calibrated X-ray facility ever flown. We discuss here the calibration of the effective area of the High Resolution Mirror Assembly. Because we do not know the absolute X-ray flux density of any celestial source, this must be based primarily on ground measurements and on modeling. In particular, we must remove the calibrated modeled responses of the detectors and gratings to obtain the mirror area. For celestial sources which may be assumed to have smoothly varying spectra, such as the Crab Nebula, we may verify the continuity of the area calibration as a function of energy. This is of significance in energy regions such as the Ir M-edges, or near the critical grazing angle cutoff of the various mirror shells.

Absolute Dimensions of the F-type Eclipsing Binary V2154 Cygni

NASA Astrophysics Data System (ADS)

Bright, Jane C.; Torres, Guillermo

2017-11-01

We report spectroscopic observations of the 2.63 day, detached, F-type main-sequence eclipsing binary V2154 Cyg. We use our observations together with existing uvby photometric measurements to derive accurate absolute masses and radii for the stars that are good to better than 1.5%. We obtain masses of {M}1=1.269+/- 0.017 {M}⊙ and {M}2=0.7542+/- 0.0059 {M}⊙ , radii of {R}1=1.477+/- 0.012 {R}⊙ and {R}2=0.7232+/- 0.0091 {R}⊙ , and effective temperatures of 6770 ± 150 K and 5020 ± 150 K for the primary and secondary stars, respectively. Both components appear to have their rotations synchronized with the motion in the circular orbit. A comparison of the properties of the primary with current stellar evolution models gives good agreement for a metallicity of [{Fe}/{{H}}]=-0.17, which is consistent with photometric estimates, and an age of about 2.2 Gyr. On the other hand, the K2 secondary is larger than predicted for its mass by about 4%. Similar discrepancies are known to exist for other cool stars, and are generally ascribed to stellar activity. The system is in fact an X-ray source, and we argue that the main site of the activity is the secondary star. Indirect estimates give a strength of about 1 kG for the average surface magnetic field on that star. A previously known close visual companion to V2154 Cyg is shown to be physically bound, making the system a hierarchical triple.

Effect of essential oils on Aspergillus spore germination, growth and mycotoxin production: a potential source of botanical food preservative

PubMed Central

Gemeda, Negero; Woldeamanuel, Yimtubezinash; Asrat, Daniel; Debella, Asfaw

2014-01-01

Objective To investigate effect of essential oils on Aspergillus spore germination, growth and mycotoxin production. Method In vitro antifungal and antiaflatoxigenic activity of essential oils was carried out using poisoned food techniques, spore germination assay, agar dilution assay, and aflatoxin arresting assay on toxigenic strains of Aspergillus species. Results Cymbopogon martinii, Foeniculum vulgare and Trachyspermum ammi (T. ammi) essential oils were tested against toxicogenic isolates of Aspergillus species. T. ammi oil showed highest antifungal activity. Absolute mycelial inhibition was recorded at 1 µl/mL by essential oils of T. ammi. The oil also showed, complete inhibition of spore germination at a concentration of 2 µl/mL. In addition, T. ammi oil showed significant antiaflatoxigenic potency by totally inhibiting aflatoxin production from Aspergillus niger and Aspergillus flavus at 0.5 and 0.75 µl/mL, respectively. Cymbopogon martinii, Foeniculum vulgare and T. ammi oils as antifungal were found superior over synthetic preservative. Moreover, a concentration of 5 336.297 µl/kg body weight was recorded for LC50 on mice indicating the low mammalian toxicity and strengthening its traditional reputations. Conclusions In conclusion, the essential oils from T. ammi can be a potential source of safe natural food preservative for food commodities contamination by storage fungi. PMID:25183114

Low Energy X-Ray and Electron Physics and Technology for High-Temperature Plasma Diagnostics

DTIC Science & Technology

1987-10-01

This program in low-energy x-ray physics and technology has expanded into a major program with the principal objective of supporting research and application programs at the new large x-ray source facilities, particularly the high temperature plasma and synchrotron radiation sources. This program addresses the development of absolute x-ray diagnostics for the fusion energy and x-ray laser research and development. The new laboratory includes five specially designed

Turbulent mass inhomogeneities induced by a point-source

NASA Astrophysics Data System (ADS)

Thalabard, Simon

2018-03-01

We describe how turbulence distributes tracers away from a localized source of injection, and analyze how the spatial inhomogeneities of the concentration field depend on the amount of randomness in the injection mechanism. For that purpose, we contrast the mass correlations induced by purely random injections with those induced by continuous injections in the environment. Using the Kraichnan model of turbulent advection, whereby the underlying velocity field is assumed to be shortly correlated in time, we explicitly identify scaling regions for the statistics of the mass contained within a shell of radius r and located at a distance ρ away from the source. The two key parameters are found to be (i) the ratio s 2 between the absolute and the relative timescales of dispersion and (ii) the ratio Λ between the size of the cloud and its distance away from the source. When the injection is random, only the former is relevant, as previously shown by Celani et al (2007 J. Fluid Mech. 583 189–98) in the case of an incompressible fluid. It is argued that the space partition in terms of s 2 and Λ is a robust feature of the injection mechanism itself, which should remain relevant beyond the Kraichnan model. This is for instance the case in a generalized version of the model, where the absolute dispersion is prescribed to be ballistic rather than diffusive.

Relation between aerosol sources and meteorological parameters for inhalable atmospheric particles in Sao Paulo City, Brazil

NASA Astrophysics Data System (ADS)

Andrade, Fatima; Orsini, Celso; Maenhaut, Willy

Stacked filter units were used to collect atmospheric particles in separate coarse and fine fractions at the Sao Paulo University Campus during the winter of 1989. The samples were analysed by particle-induced X-ray emission (PIXE) and the data were subjected to an absolute principal component analysis (APCA). Five sources were identified for the fine particles: industrial emissions, which accounted for 13% of the fine mass; emissions from residual oil and diesel, explaining 41%; resuspended soil dust, with 28%; and emissions of Cu and of Mg, together with 18%. For the coarse particles, four sources were identified: soil dust, accounting for 59% of the coarse mass; industrial emissions, with 19%; oil burning, with 8%; and sea salt aerosol, with 14% of the coarse mass. A data set with various meteorological parameters was also subjected to APCA, and a correlation analysis was performed between the meteorological "absolute principal component scores" (APCS) and the APCS from the fine and coarse particle data sets. The soil dust sources for the fine and coarse aerosol were highly correlated with each other and were anticorrelated with the sea breeze component. The industrial components in the fine and coarse size fractions were also highly positively correlated. Furthermore, the industrial component was related with the northeasterly wind direction and, to a lesser extent, with the sea breeze component.

High frequency source localization in a shallow ocean sound channel using frequency difference matched field processing.

PubMed

Worthmann, Brian M; Song, H C; Dowling, David R

2015-12-01

Matched field processing (MFP) is an established technique for source localization in known multipath acoustic environments. Unfortunately, in many situations, particularly those involving high frequency signals, imperfect knowledge of the actual propagation environment prevents accurate propagation modeling and source localization via MFP fails. For beamforming applications, this actual-to-model mismatch problem was mitigated through a frequency downshift, made possible by a nonlinear array-signal-processing technique called frequency difference beamforming [Abadi, Song, and Dowling (2012). J. Acoust. Soc. Am. 132, 3018-3029]. Here, this technique is extended to conventional (Bartlett) MFP using simulations and measurements from the 2011 Kauai Acoustic Communications MURI experiment (KAM11) to produce ambiguity surfaces at frequencies well below the signal bandwidth where the detrimental effects of mismatch are reduced. Both the simulation and experimental results suggest that frequency difference MFP can be more robust against environmental mismatch than conventional MFP. In particular, signals of frequency 11.2 kHz-32.8 kHz were broadcast 3 km through a 106-m-deep shallow ocean sound channel to a sparse 16-element vertical receiving array. Frequency difference MFP unambiguously localized the source in several experimental data sets with average peak-to-side-lobe ratio of 0.9 dB, average absolute-value range error of 170 m, and average absolute-value depth error of 10 m.

Nitrogen and Carbon Status Are Integrated at the Transcriptional Level by the Nitrogen Regulator NtrC In Vivo

PubMed Central

Schumacher, Jörg; Behrends, Volker; Pan, Zhensheng; Brown, Dan R.; Heydenreich, Franziska; Lewis, Matthew R.; Bennett, Mark H.; Razzaghi, Banafsheh; Komorowski, Michal; Barahona, Mauricio; Stumpf, Michael P. H.; Wigneshweraraj, Sivaramesh; Bundy, Jacob G.; Buck, Martin

2013-01-01

ABSTRACT Nitrogen regulation in Escherichia coli is a model system for gene regulation in bacteria. Growth on glutamine as a sole nitrogen source is assumed to be nitrogen limiting, inferred from slow growth and strong NtrB/NtrC-dependent gene activation. However, we show that under these conditions, the intracellular glutamine concentration is not limiting but 5.6-fold higher than in ammonium-replete conditions; in addition, α-ketoglutarate concentrations are elevated. We address this glutamine paradox from a systems perspective. We show that the dominant role of NtrC is to regulate glnA transcription and its own expression, indicating that the glutamine paradox is not due to NtrC-independent gene regulation. The absolute intracellular NtrC and GS concentrations reveal molecular control parameters, where NtrC-specific activities were highest in nitrogen-starved cells, while under glutamine growth, NtrC showed intermediate specific activity. We propose an in vivo model in which α-ketoglutarate can derepress nitrogen regulation despite nitrogen sufficiency. PMID:24255125

Plurality in Translation.

ERIC Educational Resources Information Center

Farahzad, Farzaneh

This paper discusses factors contributing to differing translations of the same source text, arguing that translation occurs on a continuum rather than having absolute criteria and procedures. Issues examined include the formal properties of the text, the text's "invariant core of meaning," stability in the semantic elements of the text, the text…

Pluralism--With Intelligence: A Challenge to Education and Society.

ERIC Educational Resources Information Center

Brown, Arthur

With the rise of absolutism and determinism, conformity--the conformity generated by bureaucratized social institutions, entrenched economic and political interests, monopolized sources of information, and moral majoritarianism--has begun to pose a major threat to democratic community in America. This paper focuses on the conceptual relationships…

Absolute, Extreme-Ultraviolet Solar Spectral Irradiance Monitor (AESSIM)

DTIC Science & Technology

1994-04-01

molecular constituents [Meier 1991]. This radiation is the principal source of energy for producing and maintaining the complex, time-dependent, thermal...158.4 nm emisions for interstellar wind studies. After -2005, there is unlikely to be sufficient power to provide the requisite heating of the scan

Stratospheric gravity waves at southern hemisphere orographic hotspots: 2003-2014 AIRS/Aqua observations

NASA Astrophysics Data System (ADS)

Hoffmann, Lars; Grimsdell, Alison W.; Alexander, M. Joan

2017-04-01

Stratospheric gravity waves from small-scale orographic sources are currently not well-represented in general circulation models. This may be a reason why many simulations have difficulty reproducing the dynamical behaviour of the southern hemisphere polar vortex in a realistic manner. Here we discuss a 12-year record (2003 - 2014) of stratospheric gravity wave activity at southern hemisphere orographic hotspots as observed by the Atmospheric InfraRed Sounder (AIRS) aboard the National Aeronautics and Space Administration's (NASA's) Aqua satellite. We introduce a simple and effective approach, referred to as the 'two-box method', to detect gravity wave activity from infrared nadir sounder measurements and to discriminate between gravity waves from orographic and other sources. From austral mid fall to mid spring (April - October) the contributions of orographic sources to the observed gravity wave occurrence frequencies were found to be largest for the Andes (90%), followed by the Antarctic Peninsula (76%), Kerguelen Islands (73%), Tasmania (70%), New Zealand (67%), Heard Island (60%), and other hotspots (24 - 54%). Mountain wave activity was found to be closely correlated with peak terrain altitudes, and with zonal winds in the lower troposphere and mid stratosphere. We propose a simple model to predict the occurrence of mountain wave events in the AIRS observations using zonal wind thresholds at 3 hPa and 750 hPa. The model has significant predictive skill for hotspots where gravity wave activity is primarily due to orographic sources. It typically reproduces seasonal variations of the mountain wave occurrence frequencies at the Antarctic Peninsula and Kerguelen Islands from near zero to over 60% with mean absolute errors of 4 - 5 percentage points. The prediction model can be used to disentangle upper level wind effects on observed occurrence frequencies from low level source and other influences. The data and methods presented here can help to identify interesting case studies in the vast amount of AIRS data, which could then be further explored to study the specific characteristics of stratospheric gravity waves from orographic sources and to support model validation. Reference: Hoffmann, L., Grimsdell, A. W., and Alexander, M. J.: Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003-2014 AIRS/Aqua observations, Atmos. Chem. Phys., 16, 9381-9397, doi:10.5194/acp-16-9381-2016, 2016.

On recontamination and directional-bias problems in Monte Carlo simulation of PDF turbulence models. [probability density function

NASA Technical Reports Server (NTRS)

Hsu, Andrew T.

1992-01-01

Turbulent combustion can not be simulated adequately by conventional moment closure turbulent models. The probability density function (PDF) method offers an attractive alternative: in a PDF model, the chemical source terms are closed and do not require additional models. Because the number of computational operations grows only linearly in the Monte Carlo scheme, it is chosen over finite differencing schemes. A grid dependent Monte Carlo scheme following J.Y. Chen and W. Kollmann has been studied in the present work. It was found that in order to conserve the mass fractions absolutely, one needs to add further restrictions to the scheme, namely alpha(sub j) + gamma(sub j) = alpha(sub j - 1) + gamma(sub j + 1). A new algorithm was devised that satisfied this restriction in the case of pure diffusion or uniform flow problems. Using examples, it is shown that absolute conservation can be achieved. Although for non-uniform flows absolute conservation seems impossible, the present scheme has reduced the error considerably.

Calibration of the Reflected Solar Instrument for the Climate Absolute Radiance and Refractivity Observatory

NASA Technical Reports Server (NTRS)

Thome, Kurtis; Barnes, Robert; Baize, Rosemary; O'Connell, Joseph; Hair, Jason

2010-01-01

The Climate Absolute Radiance and Refractivity Observatory (CLARREO) plans to observe climate change trends over decadal time scales to determine the accuracy of climate projections. The project relies on spaceborne earth observations of SI-traceable variables sensitive to key decadal change parameters. The mission includes a reflected solar instrument retrieving at-sensor reflectance over the 320 to 2300 nm spectral range with 500-m spatial resolution and 100-km swath. Reflectance is obtained from the ratio of measurements of the earth s surface to those while viewing the sun relying on a calibration approach that retrieves reflectance with uncertainties less than 0.3%. The calibration is predicated on heritage hardware, reduction of sensor complexity, adherence to detector-based calibration standards, and an ability to simulate in the laboratory on-orbit sources in both size and brightness to provide the basis of a transfer to orbit of the laboratory calibration including a link to absolute solar irradiance measurements.

[A correlation between diffusion kurtosis imaging and the proliferative activity of brain glioma].

PubMed

Tonoyan, A S; Pronin, I N; Pitshelauri, D I; Shishkina, L V; Fadeeva, L M; Pogosbekyan, E L; Zakharova, N E; Shults, E I; Khachanova, N V; Kornienko, V N; Potapov, A A

2015-01-01

The aim of the study was to assess the capabilities of diffusion kurtosis imaging (DKI) in diagnosis of the glioma proliferative activity and to evaluate a relationship between the glioma proliferative activity index and diffusion parameters of the contralateral normal appearing white matter (CNAWM). The study included 47 patients with newly diagnosed brain gliomas (23 low grade, 13 grade III, and 11 grade IV gliomas). We determined a relationship between absolute and normalized parameters of the diffusion tensor (mean (MD), axial (AD), and radial (RD) diffusivities; fractional (FA) and relative (RA) anisotropies) and diffusion kurtosis (mean (MK), axial (AK), and radial (RK) kurtosis; kurtosis anisotropy (KA)) and the proliferative activity index in the most malignant glioma parts (p<0.05). We also established a relationship between the tensor and kurtosis parameters of CNAWM and the glioma proliferative activity index (p<0.05). The correlation between all the absolute and normalized diffusion parameters and the glioma proliferative activity index, except absolute and normalized FA and RA values, was found to be statistically significant (p<0.05). Kurtosis (MK, AK, and RK) and anisotropy (KA, FA, RA) values increased, and diffusivity (MD, AD, RD) values decreased as the glioma proliferative activity index increased. A strong correlation between the proliferative activity index and absolute RK (r=0,71; p=0.000001) and normalized values of MK (r=0.8; p=0.000001), AK (r=0.71; p=0.000001), RK (r=0.81; p=0.000001), and RD (r=-0.71; p=0.000001) was found. A weak, but statistically significant correlation between the glioma proliferative activity index and diffusion values RK (r=-0.36; p=0.014), KA (r=-0.39; p=0.007), RD (r=0.35; p=0.017), FA (r=-0.42; p=0.003), and RA (r=-0.41; p=0.004) of CNAWM was found. DKI has good capabilities to detect immunohistochemical changes in gliomas. DKI demonstrated a high sensitivity in detection of microstructural changes in the contralateral normal appearing white matter in patients with brain gliomas.

Demonstrating the Error Budget for the Climate Absolute Radiance and Refractivity Observatory Through Solar Irradiance Measurements

NASA Technical Reports Server (NTRS)

Thome, Kurtis; McCorkel, Joel; McAndrew, Brendan

2016-01-01

The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission addresses the need to observe highaccuracy, long-term climate change trends and to use decadal change observations as a method to determine the accuracy of climate change. A CLARREO objective is to improve the accuracy of SI-traceable, absolute calibration at infrared and reflected solar wavelengths to reach on-orbit accuracies required to allow climate change observations to survive data gaps and observe climate change at the limit of natural variability. Such an effort will also demonstrate National Institute of Standards and Technology (NIST) approaches for use in future spaceborne instruments. The current work describes the results of laboratory and field measurements with the Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer (SOLARIS) which is the calibration demonstration system (CDS) for the reflected solar portion of CLARREO. SOLARIS allows testing and evaluation of calibration approaches, alternate design and/or implementation approaches and components for the CLARREO mission. SOLARIS also provides a test-bed for detector technologies, non-linearity determination and uncertainties, and application of future technology developments and suggested spacecraft instrument design modifications. Results of laboratory calibration measurements are provided to demonstrate key assumptions about instrument behavior that are needed to achieve CLARREO's climate measurement requirements. Absolute radiometric response is determined using laser-based calibration sources and applied to direct solar views for comparison with accepted solar irradiance models to demonstrate accuracy values giving confidence in the error budget for the CLARREO reflectance retrieval.

Pharmaceutical container/closure integrity. I: Mass spectrometry-based helium leak rate detection for rubber-stoppered glass vials.

PubMed

Kirsch, L E; Nguyen, L; Moeckly, C S

1997-01-01

The development of mass spectrometry-based leak detection for pharmaceutical container integrity was undertaken to provide an alternative to microbial challenge testing. Standard 10-mL vials were modified to contain pinholes (0.5 to 10 microns) by affixing micropipettes with epoxy into 2-mm vial side wall holes. The absolute leak rate was determined using vials that were sealed in a tracer (helium) environment with butyl rubber stoppers and crimps. Alternatively leak rates were determined using vials that were sealed in room air and exposed to tracer under pressure (charging or bombing). Tracer leak rates were measured with mass spectrometry leak rate detectors. The absolute leak rate was correlated the squared nominal leak radius which suggested that the mode of gas flow through the glass pipette leaks was more turbulent than viscous even at low leak rates typically associated with viscous flow. The minimum observed absolute leak rate was about 10(-6.6) std cc/sec and was likely due to helium permeation through the rubber stoppers. Heat-stressed rubber stoppers did not affect the baseline absolute leak rate. Adsorption of helium tracer to the test unit surfaces was found to confound baseline leak rate measurement reliability but was eliminated as a source of variation by exposing the test units to ambient air for > or = 12 hours. The absolute leak rate and the leak rate measured after charging were related in a mathematically predictable way.

Device for determining carbon activity through pressure

DOEpatents

Roche, Michael F.

1976-01-01

A hollow iron capsule of annular shape having an interior layer of Fe.sub.0.947 0 and a near absolute internal vacuum is submersed within a molten metal with the inner chamber of the capsule connected to a pressure sensor. Carbon present in the molten metal diffuses through the capsule wall and reacts with the Fe.sub.0.947 0 layer to generate a CO.sub.2 --CO gas mixture within the internal chamber. The total absolute pressure of the gas measured by the pressure sensor is directly proportional to the carbon activity of the molten metal.

A combined approach for the evaluation of a volatile organic compound emissions inventory.

PubMed

Choi, Yu-Jin; Calabrese, Richard V; Ehrman, Sheryl H; Dickerson, Russell R; Stehr, Jeffrey W

2006-02-01

Emissions inventories significantly affect photochemical air quality model performance and the development of effective control strategies. However, there have been very few studies to evaluate their accuracy. Here, to evaluate a volatile organic compound (VOC) emissions inventory, we implemented a combined approach: comparing the ratios of carbon bond (CB)-IV VOC groups to nitrogen oxides (NOx) or carbon monoxide (CO) using an emission preprocessing model, comparing the ratios of VOC source contributions from a source apportionment technique to NOx or CO, and comparing ratios of CB-IV VOC groups to NOx or CO and the absolute concentrations of CB-IV VOC groups using an air quality model, with the corresponding ratios and concentrations observed at three sites (Maryland, Washington, DC, and New Jersey). The comparisons of the ethene/NOx ratio, the xylene group (XYL)/NOx ratio, and ethene and XYL concentrations between estimates and measurements showed some differences, depending on the comparison approach, at the Maryland and Washington, DC sites. On the other hand, consistent results at the New Jersey site were observed, implying a possible overestimation of vehicle exhaust. However, in the case of the toluene group (TOL), which is emitted mainly from surface coating and printing sources in the solvent utilization category, the ratios of TOL/ NOx or CO, as well as the absolute concentrations revealed an overestimate of these solvent sources by a factor of 1.5 to 3 at all three sites. In addition, the overestimate of these solvent sources agreed with the comparisons of surface coating and printing source contributions relative to NOx from a source apportionment technique to the corresponding value of estimates at the Maryland site. Other studies have also suggested an overestimate of solvent sources, implying a possibility of inaccurate emission factors in estimating VOC emissions from surface coating and printing sources. We tested the impact of these overestimates with a chemical transport model and found little change in ozone but substantial changes in calculated secondary organic aerosol concentrations.

Characterization of polarimetric and total intensity behaviour of a complete sample of PACO radio sources in the radio bands

NASA Astrophysics Data System (ADS)

Galluzzi, V.; Massardi, M.; Bonaldi, A.; Casasola, V.; Gregorini, L.; Trombetti, T.; Burigana, C.; Bonato, M.; De Zotti, G.; Ricci, R.; Stevens, J.; Ekers, R. D.; Bonavera, L.; di Serego Alighieri, S.; Liuzzo, E.; López-Caniego, M.; Paladino, R.; Toffolatti, L.; Tucci, M.; Callingham, J. R.

2018-03-01

We present high sensitivity (σP ≃ 0.6 mJy) polarimetric observations in seven bands, from 2.1 to 38 GHz, of a complete sample of 104 compact extragalactic radio sources brighter than 200 mJy at 20 GHz. Polarization measurements in six bands, in the range 5.5-38 GHz, for 53 of these objects were reported by Galluzzi et al. We have added new measurements in the same six bands for another 51 sources and measurements at 2.1 GHz for the full sample of 104 sources. Also, the previous measurements at 18, 24, 33, and 38 GHz were re-calibrated using the updated model for the flux density absolute calibrator, PKS1934-638, not available for the earlier analysis. The observations, carried out with the Australia Telescope Compact Array, achieved a 90 per cent detection rate (at 5σ) in polarization. 89 of our sources have a counterpart in the 72-231 MHz GLEAM (GaLactic and Extragalactic All-sky Murchison Widefield Array) survey, providing an unparalleled spectral coverage of 2.7 decades of frequency for these sources. While the total intensity data from 5.5 to 38 GHz could be interpreted in terms of single component emission, a joint analysis of more extended total intensity spectra presented here, and of the polarization spectra, reveals that over 90 per cent of our sources show clear indications of at least two emission components. We interpret this as an evidence of recurrent activity. Our high sensitivity polarimetry has allowed a 5σ detection of the weak circular polarization for ˜ 38 per cent of the data set, and a deeper estimate of 20 GHz polarization source counts than has been possible so far.

Measurement of absolute gamma emission probabilities

NASA Astrophysics Data System (ADS)

Sumithrarachchi, Chandana S.; Rengan, Krish; Griffin, Henry C.

2003-06-01

The energies and emission probabilities (intensities) of gamma-rays emitted in radioactive decays of particular nuclides are the most important characteristics by which to quantify mixtures of radionuclides. Often, quantification is limited by uncertainties in measured intensities. A technique was developed to reduce these uncertainties. The method involves obtaining a pure sample of a nuclide using radiochemical techniques, and using appropriate fractions for beta and gamma measurements. The beta emission rates were measured using a liquid scintillation counter, and the gamma emission rates were measured with a high-purity germanium detector. Results were combined to obtain absolute gamma emission probabilities. All sources of uncertainties greater than 0.1% were examined. The method was tested with 38Cl and 88Rb.

Absolute calibration of Doppler coherence imaging velocity images

NASA Astrophysics Data System (ADS)

Samuell, C. M.; Allen, S. L.; Meyer, W. H.; Howard, J.

2017-08-01

A new technique has been developed for absolutely calibrating a Doppler Coherence Imaging Spectroscopy interferometer for measuring plasma ion and neutral velocities. An optical model of the interferometer is used to generate zero-velocity reference images for the plasma spectral line of interest from a calibration source some spectral distance away. Validation of this technique using a tunable diode laser demonstrated an accuracy better than 0.2 km/s over an extrapolation range of 3.5 nm; a two order of magnitude improvement over linear approaches. While a well-characterized and very stable interferometer is required, this technique opens up the possibility of calibrated velocity measurements in difficult viewing geometries and for complex spectral line-shapes.

Absolute photoionization cross sections of two cyclic ketones: cyclopentanone and cyclohexanone.

PubMed

Price, Chelsea; Fathi, Yasmin; Meloni, Giovanni

2017-05-01

Absolute photoionization cross sections for cyclopentanone and cyclohexanone, as well as partial ionization cross sections for the dissociative ionized fragments, are presented in this investigation. Experiments are performed via a multiplexed photoionization mass spectrometer utilizing vacuum ultraviolet (VUV) synchrotron radiation supplied by the Advanced Light Source of Lawrence Berkeley National Laboratory. These results allow the quantification of these species that is relevant to investigate the kinetics and combustion reactions of potential biofuels. The CBS-QB3 calculated values for the adiabatic ionization energies agree well with the experimental values, and the identification of possible dissociative fragments is discussed for both systems. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Absolute measurements of fast neutrons using yttrium.

PubMed

Roshan, M V; Springham, S V; Rawat, R S; Lee, P; Krishnan, M

2010-08-01

Yttrium is presented as an absolute neutron detector for pulsed neutron sources. It has high sensitivity for detecting fast neutrons. Yttrium has the property of generating a monoenergetic secondary radiation in the form of a 909 keV gamma-ray caused by inelastic neutron interaction. It was calibrated numerically using MCNPX and does not need periodic recalibration. The total yttrium efficiency for detecting 2.45 MeV neutrons was determined to be f(n) approximately 4.1x10(-4) with an uncertainty of about 0.27%. The yttrium detector was employed in the NX2 plasma focus experiments and showed the neutron yield of the order of 10(8) neutrons per discharge.

America’s First Amphetamine Epidemic 1929–1971

PubMed Central

Rasmussen, Nicolas

2008-01-01

Using historical research that draws on new primary sources, I review the causes and course of the first, mainly iatrogenic amphetamine epidemic in the United States from the 1940s through the 1960s. Retrospective epidemiology indicates that the absolute prevalence of both nonmedical stimulant use and stimulant dependence or abuse have reached nearly the same levels today as at the epidemic’s peak around 1969. Further parallels between epidemics past and present, including evidence that consumption of prescribed amphetamines has also reached the same absolute levels today as at the original epidemic’s peak, suggest that stricter limits on pharmaceutical stimulants must be considered in any efforts to reduce amphetamine abuse today. PMID:18445805

Factors affecting the accuracy of near-infrared spectroscopy concentration calculations for focal changes in oxygenation parameters

NASA Technical Reports Server (NTRS)

Strangman, Gary; Franceschini, Maria Angela; Boas, David A.; Sutton, J. P. (Principal Investigator)

2003-01-01

Near-infrared spectroscopy (NIRS) can be used to noninvasively measure changes in the concentrations of oxy- and deoxyhemoglobin in tissue. We have previously shown that while global changes can be reliably measured, focal changes can produce erroneous estimates of concentration changes (NeuroImage 13 (2001), 76). Here, we describe four separate sources for systematic error in the calculation of focal hemoglobin changes from NIRS data and use experimental methods and Monte Carlo simulations to examine the importance and mitigation methods of each. The sources of error are: (1). the absolute magnitudes and relative differences in pathlength factors as a function of wavelength, (2). the location and spatial extent of the absorption change with respect to the optical probe, (3). possible differences in the spatial distribution of hemoglobin species, and (4). the potential for simultaneous monitoring of multiple regions of activation. We found wavelength selection and optode placement to be important variables in minimizing such errors, and our findings indicate that appropriate experimental procedures could reduce each of these errors to a small fraction (<10%) of the observed concentration changes.

Derivational Suffixes as Cues to Stress Position in Reading Greek

ERIC Educational Resources Information Center

Grimani, Aikaterini; Protopapas, Athanassios

2017-01-01

Background: In languages with lexical stress, reading aloud must include stress assignment. Stress information sources across languages include word-final letter sequences. Here, we examine whether such sequences account for stress assignment in Greek and whether this is attributable to absolute rules involving accenting morphemes or to…

Alaska national hydrography dataset positional accuracy assessment study

USGS Publications Warehouse

Arundel, Samantha; Yamamoto, Kristina H.; Constance, Eric; Mantey, Kim; Vinyard-Houx, Jeremy

2013-01-01

Initial visual assessments Wide range in the quality of fit between features in NHD and these new image sources. No statistical analysis has been performed to actually quantify accuracy Determining absolute accuracy is cost prohibitive (must collect independent, well defined test points) Quantitative analysis of relative positional error is feasible.

On Fences, Forms and Mathematical Modeling

ERIC Educational Resources Information Center

Lege, Jerry

2009-01-01

The white picket fence is an integral component of the iconic American townscape. But, for mathematics students, it can be a mathematical challenge. Picket fences in a variety of styles serve as excellent sources to model constant, step, absolute value, and sinusoidal functions. "Principles and Standards for School Mathematics" (NCTM 2000)…

Contemplation and the "Performative Absolute": Submission and Identity in Managerial Modernity

ERIC Educational Resources Information Center

Roberts, Richard H.

2013-01-01

Practices derived from the "vita contemplativa" and other spiritual sources are drawn upon by management, but as the power of human resources management (HRM) is extended so the relationship between "contemplation" and the surrender of self-identity required by HRM demands critical examination. The conscious construction of the…

Macromolecular Design Strategies for Preventing Active-Material Crossover in Non-Aqueous All-Organic Redox-Flow Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doris, Sean E.; Ward, Ashleigh L.; Baskin, Artem

Intermittent energy sources, including solar and wind, require scalable, low-cost, multi-hour energy storage solutions in order to be effectively incorporated into the grid. All-Organic non-aqueous redox-flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox-active species across the battery's membrane. In this paper, we show that active-species crossover is arrested by scaling the membrane's pore size to molecular dimensions and in turn increasing the size of the active material above the membrane's pore-size exclusion limit. When oligomeric redox-active organics (RAOs) were paired with microporous polymer membranes, the ratemore » of active-material crossover was reduced more than 9000-fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm -2 day -1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. Finally, this strategy was generalizable to both high and low-potential RAOs in a variety of non-aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next-generation redox-flow batteries.« less

Macromolecular Design Strategies for Preventing Active-Material Crossover in Non-Aqueous All-Organic Redox-Flow Batteries.

PubMed

Doris, Sean E; Ward, Ashleigh L; Baskin, Artem; Frischmann, Peter D; Gavvalapalli, Nagarjuna; Chénard, Etienne; Sevov, Christo S; Prendergast, David; Moore, Jeffrey S; Helms, Brett A

2017-02-01

Intermittent energy sources, including solar and wind, require scalable, low-cost, multi-hour energy storage solutions in order to be effectively incorporated into the grid. All-Organic non-aqueous redox-flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox-active species across the battery's membrane. Here we show that active-species crossover is arrested by scaling the membrane's pore size to molecular dimensions and in turn increasing the size of the active material above the membrane's pore-size exclusion limit. When oligomeric redox-active organics (RAOs) were paired with microporous polymer membranes, the rate of active-material crossover was reduced more than 9000-fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm -2  day -1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. This strategy was generalizable to both high and low-potential RAOs in a variety of non-aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next-generation redox-flow batteries. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Macromolecular Design Strategies for Preventing Active-Material Crossover in Non-Aqueous All-Organic Redox-Flow Batteries

DOE PAGES

Doris, Sean E.; Ward, Ashleigh L.; Baskin, Artem; ...

2017-01-10

Intermittent energy sources, including solar and wind, require scalable, low-cost, multi-hour energy storage solutions in order to be effectively incorporated into the grid. All-Organic non-aqueous redox-flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox-active species across the battery's membrane. In this paper, we show that active-species crossover is arrested by scaling the membrane's pore size to molecular dimensions and in turn increasing the size of the active material above the membrane's pore-size exclusion limit. When oligomeric redox-active organics (RAOs) were paired with microporous polymer membranes, the ratemore » of active-material crossover was reduced more than 9000-fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm -2 day -1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. Finally, this strategy was generalizable to both high and low-potential RAOs in a variety of non-aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next-generation redox-flow batteries.« less

Association between absolute tumor burden and serum bone-specific alkaline phosphatase in canine appendicular osteosarcoma.

PubMed

Sternberg, R A; Pondenis, H C; Yang, X; Mitchell, M A; O'Brien, R T; Garrett, L D; Helferich, W G; Hoffmann, W E; Fan, T M

2013-01-01

In dogs with appendicular osteosarcoma (OSA), increased pretreatment serum bone-specific alkaline phosphatase (BALP) activity is a negative prognostic factor, associated with shorter disease-free intervals and survival times, but a biologic basis for observed differential serum BALP activities in canine OSA patients remains incompletely defined. Serum BALP activity will correlate with absolute tumor burden in dogs with OSA. This study included 96 client-owned dogs with appendicular OSA. In canine OSA cell lines, the expression and membranous release of BALP was evaluated in vitro. The correlation between serum BALP activity and radiographic primary tumor size was evaluated in OSA-bearing dogs. In dogs developing visceral OSA metastases, serial changes in serum BALP activities were evaluated in relation to progression of macroscopic metastases, and visceral metastatic OSA cells were evaluated for BALP expression. In vitro, BALP expression was not associated with either tumorigenic or metastatic phenotype, rather the quantity of membranous BALP released was proportional with cell density. In dogs devoid of macroscopic metastases, there was a positive correlation between serum BALP activity and absolute primary tumor size. In dogs with progressive OSA metastases, serum BALP activity increased and coincided with the development of macroscopic metastases. OSA cells derived from visceral metastatic lesions retained BALP expression. Tumor burden is a determinant of serum BALP activity in dogs with appendicular OSA. The association between increased pretreatment BALP activity and negative clinical prognosis may simply be attributed to greater initial tumor burden, and consequently more advanced tumor stage. Copyright © 2013 by the American College of Veterinary Internal Medicine.

Effect of Absolute From Hibiscus syriacus L. Flower on Wound Healing in Keratinocytes.

PubMed

Yoon, Seok Won; Lee, Kang Pa; Kim, Do-Yoon; Hwang, Dae Il; Won, Kyung-Jong; Lee, Dae Won; Lee, Hwan Myung

2017-01-01

Proliferation and migration of keratinocytes are essential for the repair of cutaneous wounds. Hibiscus syriacus L. has been used in Asian medicine; however, research on keratinocytes is inadequate. To establish the dermatological properties of absolute from Hibiscus syriacus L. flower (HSF) and to provide fundamental research for alternative medicine. We identified the composition of HSF absolute using gas chromatography-mass spectrometry analysis. We also examined the effect of HSF absolute in HaCaT cells using the XTT assay, Boyden chamber assay, sprout-out growth assay, and western blotting. We conducted an in-vivo wound healing assay in rat tail-skin. Ten major active compounds were identified from HSF absolute. As determined by the XTT assay, Boyden chamber assay, and sprout-out growth assay results, HSF absolute exhibited similar effects as that of epidermal growth factor on the proliferation and migration patterns of keratinocytes (HaCaT cells), which were significantly increased after HSF absolute treatment. The expression levels of the phosphorylated signaling proteins relevant to proliferation, including extracellular signal-regulated kinase 1/2 (Erk 1/2) and Akt, were also determined by western blot analysis. These results of our in-vitro and ex-vivo studies indicate that HSF absolute induced cell growth and migration of HaCaT cells by phosphorylating both Erk 1/2 and Akt. Moreover, we confirmed the wound-healing effect of HSF on injury of the rat tail-skin. Therefore, our results suggest that HSF absolute is promising for use in cosmetics and alternative medicine. Hisbiscus syriacus L. flower absolute increases HaCaT cell migration and proliferation. Hisbiscus syriacus L. flower absolute regulates phosphorylation of ERK 1/2 and Akt in HaCaT cell.Treatment with Hisbiscus syriacus L. flower induced sprout outgrowth.The wound in the tail-skin of rat was reduced by Hisbiscus syriacus L. flower absolute Abbreviations used: HSF: Hibiscus syriacus L. flower, Erk 1/2: extracellular signal-regulated kinase 1/2, EGF: epidermal growth factor, GC/MS: gas chromatography-mass spectrometry, DMEM: dulbecco's modified eagle medium, FBS: fetal bovine serum, BSA: bovine serum albumin, p-Akt: phosphorylation of Akt, p-Erk 1/2: phosphorylation of Erk 1/2.

Preparation by enzymolysis and bioactivity of iron complex of fish protein hydrolysate (Fe-FPH) from low value fish

NASA Astrophysics Data System (ADS)

Deng, Shanggui; Huo, Jiancong; Xie, Chao

2008-08-01

Preparation of Fe2+ chelate of fish protein hydrolysate (Fe-FPH) obtained from low value fish proteins was introduced and its bioactivity was studied by compound enzymolysis. The optimum conditions for hydrolysate chelating Fe2+ are DH (degree of hydrolysis) at 5%, pH 7.0, 20°C and 15 min chelating time for FM (material not being defatted). Four types of Fe-FPH including CA (deposit after chelating), CB (deposit in 50% of absolute ethanol solution), CC (suspended deposit in 80% of absolute ethanol solution), and CD (bottom deposit in 80% of absolute ethanol solution) were fractionated with absolute ethanol from FM. Structural analysis through infra-red spectrum revealed that Fe2+ was combined strongly with amino-group and carboxyl-group in each chelate and each Fe2+ could form two five-member ring structures. All of the four chelates were shown more significant antioxidative activity and can be used as natural hydrophobic and hydrophilic antioxidant. Among all the chelates, the CB possesses the most effective antioxidative activity at 92% as high as that of a-tocopherol. Among all Fe-FPHs, only CD showed the most effective antibacterial activity against Escherichia coli, Staphylococcus aureus, Salmonella typhi, and Bacillus subtilis and can be used as natural antibacterial. It provides a more effective way for utilization of low value fish proteins and key information of Fe-FPH as additive in food industry.

Calibration of time of flight detectors using laser-driven neutron source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mirfayzi, S. R.; Kar, S., E-mail: s.kar@qub.ac.uk; Ahmed, H.

2015-07-15

Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil.

Calibration of time of flight detectors using laser-driven neutron source.

PubMed

Mirfayzi, S R; Kar, S; Ahmed, H; Krygier, A G; Green, A; Alejo, A; Clarke, R; Freeman, R R; Fuchs, J; Jung, D; Kleinschmidt, A; Morrison, J T; Najmudin, Z; Nakamura, H; Norreys, P; Oliver, M; Roth, M; Vassura, L; Zepf, M; Borghesi, M

2015-07-01

Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil.

Calibration of time of flight detectors using laser-driven neutron source

NASA Astrophysics Data System (ADS)

Mirfayzi, S. R.; Kar, S.; Ahmed, H.; Krygier, A. G.; Green, A.; Alejo, A.; Clarke, R.; Freeman, R. R.; Fuchs, J.; Jung, D.; Kleinschmidt, A.; Morrison, J. T.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Oliver, M.; Roth, M.; Vassura, L.; Zepf, M.; Borghesi, M.

2015-07-01

Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil.

Analysing seismic-source mechanisms by linear-programming methods.

USGS Publications Warehouse

Julian, B.R.

1986-01-01

Linear-programming methods are powerful and efficient tools for objectively analysing seismic focal mechanisms and are applicable to a wide range of problems, including tsunami warning and nuclear explosion identification. The source mechanism is represented as a point in the 6-D space of moment-tensor components. The present method can easily be extended to fit observed seismic-wave amplitudes (either signed or absolute) subject to polarity constraints, and to assess the range of mechanisms consistent with a set of measured amplitudes. -from Author

Site Response for Micro-Zonation from Small Earthquakes

NASA Astrophysics Data System (ADS)

Gospe, T. B.; Hutchings, L.; Liou, I. Y. W.; Jarpe, S.

2017-12-01

We have developed a method to obtain absolute geologic site response from small earthquakes using inexpensive instrumentation that enables us to perform micro-zonation inexpensively and in a short amount of time. We record small earthquakes (M<3) at several sites simultaneously and perform inversion to obtain actual absolute site response. The key to the inversion is that recordings at several stations from an earthquake have the same moment, source corner frequency and whole path Q effect on their spectra, but have individual Kappa and spectral amplification as a function of frequency. When these source and path effects are removed and corrections for different propagation distances are performed, we are left with actual site response. We develop site response functions from 0.5 to 25.0 Hz. Cities situated near active and dangerous faults experience small earthquakes on a regular basis. We typically record at least ten small earthquakes over time to stabilize the uncertainly. Of course, dynamic soil modeling is necessary to scale our linear site response to non-linear regime for large earthquakes. Our instrumentation is very inexpensive and virtually disposable, and can be placed throughout a city at a high density. Operation only requires turning on a switch, and data processing is automated to minimize human labor. We have installed a test network and implemented our full methodology in upper Napa Valley, California where there is variable geology and nearby rock outcrop sites, and a supply of small earthquakes from the nearby Geysers development area. We test several methbods of obtaining site response. We found that rock sites have a site response of their own and distort the site response estimate based upon spectral ratios with soil sites. Also, rock sites may not even be available near all sites throughout a city. Further, H/V site response estimates from earthquakes are marginally better, but vertical motion also has a site response of its own. H/V spectral ratios of noise don't provide accurate site response estimates either. Vs30 only provides one amplification number and doesn't account for the variable three-dimensional structure beneath sites. We conclude that absolute site response obtained directly from earthquakes is the best, and possibly, the only way to get accurate site response estimates.

The Effect of Coastline Changes to Local Community's Social-Economic

NASA Astrophysics Data System (ADS)

Hassan, M. I.; Rahmat, N. H.

2016-09-01

The coastal area is absolutely essential for the purposes of resident, recreation, tourism, fisheries and agriculture as a source of socio-economic development of local community. Some of the activities will affect the coastline changes. Coastline changes may occur due to two main factors include natural factors and also by the factor of human activities in coastal areas. Sea level rise, erosion and sedimentation are among the factors that can contribute to the changes in the coastline naturally, while the reclamation and development in coastal areas are factors of coastline changes due to human activities. Resident area and all activities in coastal areas will provide economic resources to the residents of coastal areas. However, coastline changes occur in the coastal areas will affect socio-economic for local community. A significant effect can be seen through destruction of infrastructure, loss of land, and destroy of crops. Batu Pahat is an area with significant changes of coastline. The changes of coastline from 1985 to 2013 can be determined by using topographical maps in 1985 and satellite images where the changes images are taken in 2011 and 2013 respectively. To identify the changes of risk areas, Coastal Vulnerability Index (CVI) is used to indicate vulnerability for coastal areas. This change indirectly affects the source of income in their agricultural cash crops such as oil palm and coconut. Their crops destroyed and reduced due to impact of changes in the coastline. Identification of risk coastal areas needs to be done in order for the society and local authorities to be prepared for coastline changes.

Cyclic dipeptides from rhabditid entomopathogenic nematode-associated Bacillus cereus have antimicrobial activities.

PubMed

Nishanth Kumar, S; Nath, Vishnu Sukumari; Pratap Chandran, R; Nambisan, Bala

2014-02-01

The cell free culture filtrate of Bacillus cereus associated with an entomopathogenic nematode, Rhabditis (Oscheius) sp. exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by silica gel column chromatography to obtain four bioactive compounds. The structure and absolute stereochemistry of these compounds were determined based on extensive spectroscopic analyses (FABMS, (1)H NMR, (13)C NMR, (1)H-(1)H COSY, (1)H-(13)C HMBC) and Marfey's method. The compounds were identified as cyclic dipeptides (CDPs): cyclo(L-Pro-L-Trp), cyclo(L-Leu-L-Val), cyclo(D-Pro-D-Met), and cyclo(D-Pro-D-Phe), respectively. Compounds recorded significant antibacterial activity against all the test bacteria (Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant S. aureus) except cyclo(L-Leu-L-Val). Cyclo(L-Leu-L-Val) recorded activity only against Gram positive bacteria. Best antibacterial activity was recorded by cyclo(L-Pro-L-Trp) against S. aureus (4 μg/ml). The four compounds were active against all the five fungi tested (Trichophyton rubrum, Aspergillus flavus, Candida albicans, Candida tropicalis and Cryptococcus neoformans) and the activity was compared with amphotericin B, the standard fungicide. The highest activity of 1 μg/ml by cyclo(L-Pro-L-Trp) was recorded against T. rubrum, a human pathogen responsible for causing athlete's foot, jock itch, and ringworm. The activity of cyclo(L-Pro-L-Trp) against T. rubrum, C. neoformans and C. albicans were better than amphotericin B, the standard antifungal agent. To our knowledge, this is the first report of antifungal activity of CDPs against the human pathogenic fungi T. rubrum and C. neoformans. The four CDPs are nontoxic to healthy human cell line up to 200 μg/ml. We conclude that the bacterium associated with entomopathogenic nematode is promising sources of natural antimicrobial secondary metabolites, which may receive greater benefit as potential sources of new drugs in the pharmaceutical industry.

Structural and Psycho-Social Limits to Climate Change Adaptation in the Great Barrier Reef Region

PubMed Central

Evans, Louisa S.; Hicks, Christina C.; Adger, W. Neil; Barnett, Jon; Perry, Allison L.; Fidelman, Pedro; Tobin, Renae

2016-01-01

Adaptation, as a strategy to respond to climate change, has limits: there are conditions under which adaptation strategies fail to alleviate impacts from climate change. Research has primarily focused on identifying absolute bio-physical limits. This paper contributes empirical insight to an emerging literature on the social limits to adaptation. Such limits arise from the ways in which societies perceive, experience and respond to climate change. Using qualitative data from multi-stakeholder workshops and key-informant interviews with representatives of the fisheries and tourism sectors of the Great Barrier Reef region, we identify psycho-social and structural limits associated with key adaptation strategies, and examine how these are perceived as more or less absolute across levels of organisation. We find that actors experience social limits to adaptation when: i) the effort of pursuing a strategy exceeds the benefits of desired adaptation outcomes; ii) the particular strategy does not address the actual source of vulnerability, and; iii) the benefits derived from adaptation are undermined by external factors. We also find that social limits are not necessarily more absolute at higher levels of organisation: respondents perceived considerable opportunities to address some psycho-social limits at the national-international interface, while they considered some social limits at the local and regional levels to be effectively absolute. PMID:26960200

Structural and Psycho-Social Limits to Climate Change Adaptation in the Great Barrier Reef Region.

PubMed

Evans, Louisa S; Hicks, Christina C; Adger, W Neil; Barnett, Jon; Perry, Allison L; Fidelman, Pedro; Tobin, Renae

2016-01-01

Adaptation, as a strategy to respond to climate change, has limits: there are conditions under which adaptation strategies fail to alleviate impacts from climate change. Research has primarily focused on identifying absolute bio-physical limits. This paper contributes empirical insight to an emerging literature on the social limits to adaptation. Such limits arise from the ways in which societies perceive, experience and respond to climate change. Using qualitative data from multi-stakeholder workshops and key-informant interviews with representatives of the fisheries and tourism sectors of the Great Barrier Reef region, we identify psycho-social and structural limits associated with key adaptation strategies, and examine how these are perceived as more or less absolute across levels of organisation. We find that actors experience social limits to adaptation when: i) the effort of pursuing a strategy exceeds the benefits of desired adaptation outcomes; ii) the particular strategy does not address the actual source of vulnerability, and; iii) the benefits derived from adaptation are undermined by external factors. We also find that social limits are not necessarily more absolute at higher levels of organisation: respondents perceived considerable opportunities to address some psycho-social limits at the national-international interface, while they considered some social limits at the local and regional levels to be effectively absolute.

Gastroprotective effects and antimicrobial activity of Lithraea molleoides and isolated compounds against Helicobacter pylori.

PubMed

Garro, María Filomena; Salinas Ibáñez, Angel Gabriel; Vega, Alba Edith; Arismendi Sosa, Andrea Celeste; Pelzer, Lilian; Saad, José Roberto; Maria, Alejandra Olivia

2015-12-24

Lithraea molleoides (Vell.) Engl. (Anacardiaceae) is a medicinal plant traditionally used in South America to treat various ailments, including diseases of the digestive system. To evaluate the in vivo antiulcer and antimicrobial activities against Helicobacter pylori of L. molleoides and its isolated compounds. Methanolic extract 250 and 500 mg/kg, (LmE 250 and LmE 500, respectively) and infusions, 10 g and 20 g en 100mL (LmI 10 and LmI 20, respectively) of L. molleoides was evaluated for antiulcer activity against 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol-induced gastric ulcers in rats. The degree of erosion in the glandular part of the stomach was assessed from a scoring system. Acute toxicity in mice was also evaluated. The antiulcer effect of the isolated compounds (catechol, mannitol, rutin, gallic acid, ferulic acid and caffeic acid, 100mg/kg) was evaluated against absolute ethanol-induced gastric ulcers in rats. The anti-Helicobacter pylori activity of L. molleoides and isolated compounds was performed using broth dilution methods. The LmE 250, LmE 500, LmI 10 and LmI 20 produced significant inhibition on the ulcer index in 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol- induced gastric ulcers in rats. The isolated compounds, catechol, mannitol, rutin, ferulic acid and caffeic acid were active in absolute ethanol- induced gastric ulcers in rats. L. molleoides and different compounds showed antimicrobial activity in all strains tested. The lowest MIC value (0. 5 μg/mL) was obtained with catechol in six of eleven strains assayed. No signs of toxicity were observed with doses up to 2g/kg in an acute toxicity assay. These findings indicate that L. molleoides displays potential antiulcerogenic and antimicrobial activities and the identification of active principles could support the use of this plant for the treatment of digestive affections. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

242Pu absolute neutron-capture cross section measurement

NASA Astrophysics Data System (ADS)

Buckner, M. Q.; Wu, C. Y.; Henderson, R. A.; Bucher, B.; Chyzh, A.; Bredeweg, T. A.; Baramsai, B.; Couture, A.; Jandel, M.; Mosby, S.; O'Donnell, J. M.; Ullmann, J. L.

2017-09-01

The absolute neutron-capture cross section of 242Pu was measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. During target fabrication, a small amount of 239Pu was added to the active target so that the absolute scale of the 242Pu(n,γ) cross section could be set according to the known 239Pu(n,f) resonance at En,R = 7.83 eV. The relative scale of the 242Pu(n,γ) cross section covers four orders of magnitude for incident neutron energies from thermal to ≈ 40 keV. The cross section reported in ENDF/B-VII.1 for the 242Pu(n,γ) En,R = 2.68 eV resonance was found to be 2.4% lower than the new absolute 242Pu(n,γ) cross section.

Calibration and deployment of a new NIST transfer radiometer for broadband and spectral calibration of space chambers (MDXR)

NASA Astrophysics Data System (ADS)

Jung, Timothy M.; Carter, Adriaan C.; Woods, Solomon I.; Kaplan, Simon G.

2011-06-01

The Low-Background Infrared (LBIR) facility at NIST has performed on-site calibration and initial off-site deployments of a new infrared transfer radiometer with an integrated cryogenic Fourier transform spectrometer (Cryo- FTS). This mobile radiometer can be deployed to customer sites for broadband and spectral calibrations of space chambers and low-background hardware-in-the-loop testbeds. The Missile Defense Transfer Radiometer (MDXR) has many of the capabilities of a complete IR calibration facility and replaces our existing filter-based transfer radiometer (BXR) as the NIST standard detector deployed to customer facilities. The MDXR features numerous improvements over the BXR, including: a cryogenic Fourier transform spectrometer, an on-board absolute cryogenic radiometer (ACR) and an internal blackbody reference source with an integrated collimator. The Cryo-FTS can be used to measure high resolution spectra from 3 to 28 micrometers, using a Si:As blocked-impurity-band (BIB) detector. The on-board ACR can be used for self-calibration of the MDXR BIB as well as for absolute measurements of external infrared sources. A set of filter wheels and a rotating polarizer within the MDXR allow for filter-based and polarization-sensitive measurements. The optical design of the MDXR makes both radiance and irradiance measurements possible and enables calibration of both divergent and collimated sources. Results of on-site calibration of the MDXR using its internal blackbody source and an external reference source will be discussed, as well as the performance of the new radiometer in its initial deployments to customer sites.

A 2 epoch proper motion catalogue from the UKIDSS Large Area Survey

NASA Astrophysics Data System (ADS)

Smith, Leigh; Lucas, Phil; Burningham, Ben; Jones, Hugh; Pinfield, David; Smart, Ricky; Andrei, Alexandre

2013-04-01

The UKIDSS Large Area Survey (LAS) began in 2005, with the start of the UKIDSS program as a 7 year effort to survey roughly 4000 square degrees at high galactic latitudes in Y, J, H and K bands. The survey also included a significant quantity of 2-epoch J band observations, with epoch baselines ranging from 2 to 7 years. We present a proper motion catalogue for the 1500 square degrees of the 2 epoch LAS data, which includes some 800,000 sources with motions detected above the 5σ level. We developed a bespoke proper motion pipeline which applies a source-unique second order polynomial transformation to UKIDSS array coordinates of each source to counter potential local non-uniformity in the focal plane. Our catalogue agrees well with the proper motion data supplied in the current WFCAM Science Archive (WSA) DR9 catalogue where there is overlap, and in various optical catalogues, but it benefits from some improvements. One improvement is that we provide absolute proper motions, using LAS galaxies for the relative to absolute correction. Also, by using unique, local, 2nd order polynomial tranformations, as opposed to the linear transformations in the WSA, we correct better for any local distortions in the focal plane, not including the radial distortion that is removed by their pipeline.

Comparison of measured and modelled negative hydrogen ion densities at the ECR-discharge HOMER

NASA Astrophysics Data System (ADS)

Rauner, D.; Kurutz, U.; Fantz, U.

2015-04-01

As the negative hydrogen ion density nH- is a key parameter for the investigation of negative ion sources, its diagnostic quantification is essential in source development and operation as well as for fundamental research. By utilizing the photodetachment process of negative ions, generally two different diagnostic methods can be applied: via laser photodetachment, the density of negative ions is measured locally, but only relatively to the electron density. To obtain absolute densities, the electron density has to be measured additionally, which induces further uncertainties. Via cavity ring-down spectroscopy (CRDS), the absolute density of H- is measured directly, however LOS-averaged over the plasma length. At the ECR-discharge HOMER, where H- is produced in the plasma volume, laser photodetachment is applied as the standard method to measure nH-. The additional application of CRDS provides the possibility to directly obtain absolute values of nH-, thereby successfully bench-marking the laser photodetachment system as both diagnostics are in good agreement. In the investigated pressure range from 0.3 to 3 Pa, the measured negative hydrogen ion density shows a maximum at 1 to 1.5 Pa and an approximately linear response to increasing input microwave powers from 200 up to 500 W. Additionally, the volume production of negative ions is 0-dimensionally modelled by balancing H- production and destruction processes. The modelled densities are adapted to the absolute measurements of nH- via CRDS, allowing to identify collisions of H- with hydrogen atoms (associative and non-associative detachment) to be the dominant loss process of H- in the plasma volume at HOMER. Furthermore, the characteristic peak of nH- observed at 1 to 1.5 Pa is identified to be caused by a comparable behaviour of the electron density with varying pressure, as ne determines the volume production rate via dissociative electron attachment to vibrationally excited hydrogen molecules.

Comparison of absolute gain photometric calibration between Planck/HFI and Herschel/SPIRE at 545 and 857 GHz

NASA Astrophysics Data System (ADS)

Bertincourt, B.; Lagache, G.; Martin, P. G.; Schulz, B.; Conversi, L.; Dassas, K.; Maurin, L.; Abergel, A.; Beelen, A.; Bernard, J.-P.; Crill, B. P.; Dole, H.; Eales, S.; Gudmundsson, J. E.; Lellouch, E.; Moreno, R.; Perdereau, O.

2016-04-01

We compare the absolute gain photometric calibration of the Planck/HFI and Herschel/SPIRE instruments on diffuse emission. The absolute calibration of HFI and SPIRE each relies on planet flux measurements and comparison with theoretical far-infrared emission models of planetary atmospheres. We measure the photometric cross calibration between the instruments at two overlapping bands, 545 GHz/500 μm and 857 GHz/350 μm. The SPIRE maps used have been processed in the Herschel Interactive Processing Environment (Version 12) and the HFI data are from the 2015 Public Data Release 2. For our study we used 15 large fields observed with SPIRE, which cover a total of about 120 deg2. We have selected these fields carefully to provide high signal-to-noise ratio, avoid residual systematics in the SPIRE maps, and span a wide range of surface brightness. The HFI maps are bandpass-corrected to match the emission observed by the SPIRE bandpasses. The SPIRE maps are convolved to match the HFI beam and put on a common pixel grid. We measure the cross-calibration relative gain between the instruments using two methods in each field, pixel-to-pixel correlation and angular power spectrum measurements. The SPIRE/HFI relative gains are 1.047 (±0.0069) and 1.003 (±0.0080) at 545 and 857 GHz, respectively, indicating very good agreement between the instruments. These relative gains deviate from unity by much less than the uncertainty of the absolute extended emission calibration, which is about 6.4% and 9.5% for HFI and SPIRE, respectively, but the deviations are comparable to the values 1.4% and 5.5% for HFI and SPIRE if the uncertainty from models of the common calibrator can be discounted. Of the 5.5% uncertainty for SPIRE, 4% arises from the uncertainty of the effective beam solid angle, which impacts the adopted SPIRE point source to extended source unit conversion factor, highlighting that as a focus for refinement.

Spectral radiance source based on supercontinuum laser and wavelength tunable bandpass filter: the spectrally tunable absolute irradiance and radiance source.

PubMed

Levick, Andrew P; Greenwell, Claire L; Ireland, Jane; Woolliams, Emma R; Goodman, Teresa M; Bialek, Agnieszka; Fox, Nigel P

2014-06-01

A new spectrally tunable source for calibration of radiometric detectors in radiance, irradiance, or power mode has been developed and characterized. It is termed the spectrally tunable absolute irradiance and radiance source (STAIRS). It consists of a supercontinuum laser, wavelength tunable bandpass filter, power stabilization feedback control scheme, and output coupling optics. It has the advantages of relative portability and a collimated beam (low étendue), and is an alternative to conventional sources such as tungsten lamps, blackbodies, or tunable lasers. The supercontinuum laser is a commercial Fianium SC400-6-02, which has a wavelength range between 400 and 2500 nm and a total power of 6 W. The wavelength tunable bandpass filter, a PhotonEtc laser line tunable filter (LLTF), is tunable between 400 and 1000 nm and has a bandwidth of 1 or 2 nm depending on the wavelength selected. The collimated laser beam from the LLTF filter is converted to an appropriate spatial and angular distribution for the application considered (i.e., for radiance, irradiance, or power mode calibration of a radiometric sensor) with the output coupling optics, for example, an integrating sphere, and the spectral radiance/irradiance/power of the source is measured using a calibration optical sensor. A power stabilization feedback control scheme has been incorporated that stabilizes the source to better than 0.01% for averaging times longer than 100 s. The out-of-band transmission of the LLTF filter is estimated to be < -65 dB (0.00003%), and is sufficiently low for many end-user applications, for example the spectral radiance calibration of earth observation imaging radiometers and the stray light characterization of array spectrometers (the end-user optical sensor). We have made initial measurements of two end-user instruments with the STAIRS source, an array spectrometer and ocean color radiometer.

The Seventh SeaWiFS Intercalibration Round-Robin Experiment (SIRREX-7), March 1999

NASA Technical Reports Server (NTRS)

Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); McLean, Scott; Sherman, Jennifer; Small, Mark; Lazin, Gordana; Zibordi, Giuseppe; Brown, James W.; McClain, Charles R. (Technical Monitor)

2002-01-01

This report documents the scientific activities during the seventh SeaWiFS Intercalibration Round-Robin Experiment (SIRREX-7) held at Satlantic, Inc. (Halifax, Canada). The overall objective of SIRREX-7 was to determine the uncertainties of radiometric calibrations and measurements at a single calibration facility. Specifically, this involved the estimation of the uncertainties in a) lamp standards, b) plaque standards (including the uncertainties associated with plaque illumination non-uniformity), c) radiance calibrations, and d) irradiance calibrations. The investigation of the uncertainties in lamp standards included a comparison between a calibration of a new FEL by the National Institute of Standards and Technology (NIST) and Optronic Laboratories, Inc. In addition, the rotation and polarization sensitivity of radiometers were determined, and a procedure for transferring an absolute calibration to portable light sources was defined and executed.

Crucial role of neutrinos in the electroweak symmetry breaking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smetana, Adam

2013-12-30

Not only the top-quark condensate appears to be the natural significant source of dynamical electroweak symmetry breaking. Provided the seesaw scenario, the neutrinos can have their Dirac masses large enough so that their condensates contribute significantly to the electroweak scale as well. We address the question of a phenomenological feasibility of the top-quark and neutrino condensation conspiracy against the electroweak symmetry within the simplifying two-composite-Higgs-doublet model. Mandatory is to reproduce the masses of electroweak gauge bosons, the top-quark mass and the recently observed scalar mass of 125 GeV, and to satisfy the upper limits on absolute value of active neutrinomore » masses. To accomplish that, the number of right-handed neutrinos participating on the seesaw mechanism turns out to be rather large, O(100–1000)« less

Jasmine absolute (Jasminum grandiflora L.) and its mode of action on guinea-pig ileum in vitro.

PubMed

Lis-Balchin, M; Hart, S; Wan Hang Lo, B

2002-08-01

Jasmine (Jasminum grandiflorum L.) is used in aromatherapy as a holistic treatment for apathy, hysteria, uterine disorders and childbirth, muscle relaxation and coughs. Its stimulant nature, on inhalation, has been shown both in animals and man. Jasmine has a spasmolytic activity on guinea-pig ileum and rat uterus in vitro. The mechanism of action of the spasmolytic activity, studied in vitro using a guinea-pig ileum smooth muscle preparation, was postsynaptic and not atropine-like. The spasmolytic effect of jasmine absolute was most likely to be mediated through cAMP, and not through cGMP. The mode of action in vitro resembled that of geranium, lavender and peppermint oils. The contradictory effect in vitro and in vivo is probably due to the solely physiological effects of jasmine absolute in vitro (producing a relaxation) compared with that in vivo, where it has a strong psychological input, producing a stimulant effect in man and enhanced movement in animals. Copyright 2002 John Wiley & Sons, Ltd.

Optimization of KOH etching parameters for quantitative defect recognition in n- and p-type doped SiC

NASA Astrophysics Data System (ADS)

Sakwe, S. A.; Müller, R.; Wellmann, P. J.

2006-04-01

We have developed a KOH-based defect etching procedure for silicon carbide (SiC), which comprises in situ temperature measurement and control of melt composition. As benefit for the first time reproducible etching conditions were established (calibration plot, etching rate versus temperature and time); the etching procedure is time independent, i.e. no altering in KOH melt composition takes place, and absolute melt temperature values can be set. The paper describes this advanced KOH etching furnace, including the development of a new temperature sensor resistant to molten KOH. We present updated, absolute KOH etching parameters of n-type SiC and new absolute KOH etching parameters for low and highly p-type doped SiC, which are used for quantitative defect analysis. As best defect etching recipes we found T=530 °C/5 min (activation energy: 16.4 kcal/mol) and T=500 °C/5 min (activation energy: 13.5 kcal/mol) for n-type and p-type SiC, respectively.

Measuring THz QCL feedback using an integrated monolithic transceiver.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wanke, Michael Clement

2010-08-01

THz quantum cascade lasers are of interest for use as solid-state local-oscillators in THz heterodyne receiver systems, especially for frequencies exceeding 2 THz and for use with non-cryogenic mixers which require mW power levels. Among other criteria, to be a good local oscillator, the laser must have a narrow linewidth and excellent frequency stability. Recent phase locking measurements of THz QCLs to high harmonics of microwave frequency reference sources as high as 2.7 THz demonstrate that the linewidth and frequency stability of QCLs can be more than adequate. Most reported THz receivers employing QCLs have used discrete source and detectormore » components coupled via mechanically aligned free-space quasioptics. Unfortunately, retroreflections of the laser off of the detecting element can lead to deleterious feedback effects. Using a monolithically integrated transceiver with a Schottky diode monolithically integrated into a THz QCL, we have begun to explore the sensitivity of the laser performance to feedback due to retroreflections of the THz laser radiation. The transceiver allows us to monitor the beat frequency between internal Fabry-Perot modes of the QCL or between a QCL mode and external radiation incident on the transceiver. When some of the power from a free running Fabry-Perot type QCL is retroreflected with quasi-static optics we observe frequency pulling, mode splitting and chaos. Given the lack of calibrated frequency sources with sufficient stability and power to phase lock a QCL above a couple THz, attempts have been made to lock the absolute laser frequency by locking the beat frequency of a multimoded laser. We have phase locked the beat frequency between Fabry-Perot modes to an {approx}13 GHz microwave reference source with a linewidth less than 1 Hz, but did not see any improvment in stability of the absolute frequency of the laser. In this case, when some laser power is retroreflected back into the laser, the absolute frequency can be pulled significantly as a function of the external path length.« less

Automated control of linear constricted plasma source array

DOEpatents

Anders, Andre; Maschwitz, Peter A.

2000-01-01

An apparatus and method for controlling an array of constricted glow discharge chambers are disclosed. More particularly a linear array of constricted glow plasma sources whose polarity and geometry are set so that the contamination and energy of the ions discharged from the sources are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a plasma with contamination below practical detection limits. The quality of film along deposition "tracks" opposite the plasma sources can be measured and compared to desired absolute or relative values by optical and/or electrical sensors. Plasma quality can then be adjusted by adjusting the power current values, gas feed pressure/flow, gas mixtures or a combination of some or all of these to improve the match between the measured values and the desired values.

A practical approach to reduce interference due to in-source collision-induced dissociation of acylglucuronides in LC-MS/MS.

PubMed

Mess, Jean-Nicholas; Bérubé, Eugénie-Raphaelle; Furtado, Milton; Garofolo, Fabio

2011-08-01

In LC-MS/MS, glucuronide conjugated metabolites may convert back to the parent drug due to in-source collision-induced dissociation (CID). During the bioanalysis of naproxen, it was noticed that naproxen acylglucuronide exhibited intense in-source CID to the naproxen [M+H](+) ion under positive ESI. However, no in-source CID of the acylglucuronide to the naproxen [M+NH(4)](+) adduct was observed. Furthermore, absolutely no in-source CID was detected under negative ESI. This phenomenon was not only observed for naproxen acylglucuronide but for eight other acylglucuronides compounds. We have shown that monitoring the parent drug [M-H](-) or [M+NH(4)](+) whenever possible could be an easy approach used by bioanalytical scientists to minimize the impact of in-source CID of acylglucuronides to the parent drug.

Background risk of breast cancer and the association between physical activity and mammographic density.

PubMed

Trinh, Thang; Eriksson, Mikael; Darabi, Hatef; Bonn, Stephanie E; Brand, Judith S; Cuzick, Jack; Czene, Kamila; Sjölander, Arvid; Bälter, Katarina; Hall, Per

2015-04-02

High physical activity has been shown to decrease the risk of breast cancer, potentially by a mechanism that also reduces mammographic density. We tested the hypothesis that the risk of developing breast cancer in the next 10 years according to the Tyrer-Cuzick prediction model influences the association between physical activity and mammographic density. We conducted a population-based cross-sectional study of 38,913 Swedish women aged 40-74 years. Physical activity was assessed using the validated web-questionnaire Active-Q and mammographic density was measured by the fully automated volumetric Volpara method. The 10-year risk of breast cancer was estimated using the Tyrer-Cuzick (TC) prediction model. Linear regression analyses were performed to assess the association between physical activity and volumetric mammographic density and the potential interaction with the TC breast cancer risk. Overall, high physical activity was associated with lower absolute dense volume. As compared to women with the lowest total activity level (<40 metabolic equivalent hours [MET-h] per day), women with the highest total activity level (≥50 MET-h/day) had an estimated 3.4 cm(3) (95% confidence interval, 2.3-4.7) lower absolute dense volume. The inverse association was seen for any type of physical activity among women with <3.0% TC 10-year risk, but only for total and vigorous activities among women with 3.0-4.9% TC risk, and only for vigorous activity among women with ≥5.0% TC risk. The association between total activity and absolute dense volume was modified by the TC breast cancer risk (P interaction = 0.05). As anticipated, high physical activity was also associated with lower non-dense volume. No consistent association was found between physical activity and percent dense volume. Our results suggest that physical activity may decrease breast cancer risk through reducing mammographic density, and that the physical activity needed to reduce mammographic density may depend on background risk of breast cancer.

Omega Dante Soft X-Ray Power Diagnostic Component Calibration at the National Synchrotron Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, K; Weber, F; Dewald, E

2004-04-15

The Dante soft x-ray spectrometer installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester is a twelve-channel filter-edge defined x-ray power diagnostic. It is used to measure the absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Calibration efforts using two beam lines, U3C (50eV-1keV) and X8A (1keV-6keV) at the National Synchrotron Light Source (NSLS) have been implemented to insure the accuracy of these measurements. We have calibrated vacuum x-ray diodes, mirrors and filters.

Estimating the reliability of glycemic index values and potential sources of methodological and biological variability

USDA-ARS?s Scientific Manuscript database

Background: The utility of glycemic index (GI) values for chronic disease risk management remains controversial. While absolute GI value determinations for individual foods have been shown to vary significantly in individuals with diabetes, there is a dearth of data on the reliability of GI value de...

Quantum efficiency measurement of the Transiting Exoplanet Survey Satellite (TESS) CCD detectors

NASA Astrophysics Data System (ADS)

Krishnamurthy, A.; Villasenor, J.; Thayer, C.; Kissel, S.; Ricker, G.; Seager, S.; Lyle, R.; Deline, A.; Morgan, E.; Sauerwein, T.; Vanderspek, R.

2016-07-01

Very precise on-ground characterization and calibration of TESS CCD detectors will significantly assist in the analysis of the science data from the mission. An accurate optical test bench with very high photometric stability has been developed to perform precise measurements of the absolute quantum efficiency. The setup consists of a vacuum dewar with a single MIT Lincoln Lab CCID-80 device mounted on a cold plate with the calibrated reference photodiode mounted next to the CCD. A very stable laser-driven light source is integrated with a closed-loop intensity stabilization unit to control variations of the light source down to a few parts-per-million when averaged over 60 s. Light from the stabilization unit enters a 20 inch integrating sphere. The output light from the sphere produces near-uniform illumination on the cold CCD and on the calibrated reference photodiode inside the dewar. The ratio of the CCD and photodiode signals provides the absolute quantum efficiency measurement. The design, key features, error analysis, and results from the test campaign are presented.

Atmospheric Longwave Irradiance Uncertainty: Pyrgeometers Compared to an Absolute Sky-Scanning Radiometer, Atmospheric Emitted Radiance Interferometer, and Radiative Transfer Model Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Philipona, J. R.; Dutton, Ellsworth G.; Stoffel, T.

2001-06-04

Because atmospheric longwave radiation is one of the most fundamental elements of an expected climate change, there has been a strong interest in improving measurements and model calculations in recent years. Important questions are how reliable and consistent are atmospheric longwave radiation measurements and calculations and what are the uncertainties? The First International Pyrgeometer and Absolute Sky-scanning Radiometer Comparison, which was held at the Atmospheric Radiation Measurement program's Souther Great Plains site in Oklahoma, answers these questions at least for midlatitude summer conditions and reflects the state of the art for atmospheric longwave radiation measurements and calculations. The 15 participatingmore » pyrgeometers were all calibration-traced standard instruments chosen from a broad international community. Two new chopped pyrgeometers also took part in the comparison. And absolute sky-scanning radiometer (ASR), which includes a pyroelectric detector and a reference blackbody source, was used for the first time as a reference standard instrument to field calibrate pyrgeometers during clear-sky nighttime measurements. Owner-provided and uniformly determined blackbody calibration factors were compared. Remarkable improvements and higher pyrgeometer precision were achieved with field calibration factors. Results of nighttime and daytime pyrgeometer precision and absolute uncertainty are presented for eight consecutive days of measurements, during which period downward longwave irradiance varied between 260 and 420 W m-2. Comparisons between pyrgeometers and the absolute ASR, the atmospheric emitted radiance interferometer, and radiative transfer models LBLRTM and MODTRAN show a surprisingly good agreement of <2 W m-2 for nighttime atmospheric longwave irradiance measurements and calculations.« less

Lunar Spectral Irradiance and Radiance (LUSI): New Instrumentation to Characterize the Moon as a Space-Based Radiometric Standard

PubMed Central

Smith, Allan W.; Lorentz, Steven R.; Stone, Thomas C.; Datla, Raju V.

2012-01-01

The need to understand and monitor climate change has led to proposed radiometric accuracy requirements for space-based remote sensing instruments that are very stringent and currently outside the capabilities of many Earth orbiting instruments. A major problem is quantifying changes in sensor performance that occur from launch and during the mission. To address this problem on-orbit calibrators and monitors have been developed, but they too can suffer changes from launch and the harsh space environment. One solution is to use the Moon as a calibration reference source. Already the Moon has been used to remove post-launch drift and to cross-calibrate different instruments, but further work is needed to develop a new model with low absolute uncertainties capable of climate-quality absolute calibration of Earth observing instruments on orbit. To this end, we are proposing an Earth-based instrument suite to measure the absolute lunar spectral irradiance to an uncertainty1 of 0.5 % (k=1) over the spectral range from 320 nm to 2500 nm with a spectral resolution of approximately 0.3 %. Absolute measurements of lunar radiance will also be acquired to facilitate calibration of high spatial resolution sensors. The instruments will be deployed at high elevation astronomical observatories and flown on high-altitude balloons in order to mitigate the effects of the Earth’s atmosphere on the lunar observations. Periodic calibrations using instrumentation and techniques available from NIST will ensure traceability to the International System of Units (SI) and low absolute radiometric uncertainties. PMID:26900523

Lunar Spectral Irradiance and Radiance (LUSI): New Instrumentation to Characterize the Moon as a Space-Based Radiometric Standard.

PubMed

Smith, Allan W; Lorentz, Steven R; Stone, Thomas C; Datla, Raju V

2012-01-01

The need to understand and monitor climate change has led to proposed radiometric accuracy requirements for space-based remote sensing instruments that are very stringent and currently outside the capabilities of many Earth orbiting instruments. A major problem is quantifying changes in sensor performance that occur from launch and during the mission. To address this problem on-orbit calibrators and monitors have been developed, but they too can suffer changes from launch and the harsh space environment. One solution is to use the Moon as a calibration reference source. Already the Moon has been used to remove post-launch drift and to cross-calibrate different instruments, but further work is needed to develop a new model with low absolute uncertainties capable of climate-quality absolute calibration of Earth observing instruments on orbit. To this end, we are proposing an Earth-based instrument suite to measure the absolute lunar spectral irradiance to an uncertainty(1) of 0.5 % (k=1) over the spectral range from 320 nm to 2500 nm with a spectral resolution of approximately 0.3 %. Absolute measurements of lunar radiance will also be acquired to facilitate calibration of high spatial resolution sensors. The instruments will be deployed at high elevation astronomical observatories and flown on high-altitude balloons in order to mitigate the effects of the Earth's atmosphere on the lunar observations. Periodic calibrations using instrumentation and techniques available from NIST will ensure traceability to the International System of Units (SI) and low absolute radiometric uncertainties.

Sub-nanometer periodic nonlinearity error in absolute distance interferometers

NASA Astrophysics Data System (ADS)

Yang, Hongxing; Huang, Kaiqi; Hu, Pengcheng; Zhu, Pengfei; Tan, Jiubin; Fan, Zhigang

2015-05-01

Periodic nonlinearity which can result in error in nanometer scale has become a main problem limiting the absolute distance measurement accuracy. In order to eliminate this error, a new integrated interferometer with non-polarizing beam splitter is developed. This leads to disappearing of the frequency and/or polarization mixing. Furthermore, a strict requirement on the laser source polarization is highly reduced. By combining retro-reflector and angel prism, reference and measuring beams can be spatially separated, and therefore, their optical paths are not overlapped. So, the main cause of the periodic nonlinearity error, i.e., the frequency and/or polarization mixing and leakage of beam, is eliminated. Experimental results indicate that the periodic phase error is kept within 0.0018°.

Absolute photoionization cross sections of furanic fuels: 2-ethylfuran, 2-acetylfuran and furfural.

PubMed

Smith, Audrey R; Meloni, Giovanni

2015-11-01

Absolute photoionization cross sections of the molecules 2-ethylfuran, 2-acetylfuran and furfural, including partial ionization cross sections for the dissociative ionized fragments, are measured for the first time. These measurements are important because they allow fuel quantification via photoionization mass spectrometry and the development of quantitative kinetic modeling for the complex combustion of potential fuels. The experiments are carried out using synchrotron photoionization mass spectrometry with an orthogonal time-of-flight spectrometer used for mass analysis at the Advanced Light Source of Lawrence Berkeley National Laboratory. The CBS-QB3 calculations of adiabatic ionization energies and appearance energies agree well with the experimental results. Several bond dissociation energies are also derived and presented. Copyright © 2015 John Wiley & Sons, Ltd.

Complete Hexose Isomer Identification with Mass Spectrometry

NASA Astrophysics Data System (ADS)

Nagy, Gabe; Pohl, Nicola L. B.

2015-04-01

The first analytical method is presented for the identification and absolute configuration determination of all 24 aldohexose and 2-ketohexose isomers, including the D and L enantiomers for allose, altrose, galactose, glucose, gulose, idose, mannose, talose, fructose, psicose, sorbose, and tagatose. Two unique fixed ligand kinetic method combinations were discovered to create significant enough energetic differences to achieve chiral discrimination among all 24 hexoses. Each of these 24 hexoses yields unique ratios of a specific pair of fragment ions that allows for simultaneous determination of identification and absolute configuration. This mass spectrometric-based methodology can be readily employed for accurate identification of any isolated monosaccharide from an unknown biological source. This work provides a key step towards the goal of complete de novo carbohydrate analysis.

Absolute measurement of undulator radiation in the extreme ultraviolet

NASA Astrophysics Data System (ADS)

Maezawa, H.; Mitani, S.; Suzuki, Y.; Kanamori, H.; Tamamushi, S.; Mikuni, A.; Kitamura, H.; Sasaki, T.

1983-04-01

The spectral brightness of undulator radiation emitted by the model PMU-1 incorporated in the SOR-RING, the dedicated synchrotron radiation source in Tokyo, has been studied in the extreme ultraviolet region from 21.6 to 72.9 eV as a function of the electron energy γ, the field parameter K, and the angle of observation ϴ in the absolute scale. A series of measurements covering the first and the second harmonic component of undulator radiation was compared with the fundamental formula λ n= {λ 0}/{2nγ 2}( {1+K 2}/{2}+γϴ 2 and the effects of finite emittance were studied. The brightness at the first peak was smaller than the theoretical value, while an enhanced second harmonic component was observed.

Design of a cavity ring-down spectroscopy diagnostic for negative ion rf source SPIDER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasqualotto, R.; Alfier, A.; Lotto, L.

2010-10-15

The rf source test facility SPIDER will test and optimize the source of the 1 MV neutral beam injection systems for ITER. Cavity ring-down spectroscopy (CRDS) will measure the absolute line-of-sight integrated density of negative (H{sup -} and D{sup -}) ions, produced in the extraction region of the source. CRDS takes advantage of the photodetachment process: negative ions are converted to neutral hydrogen atoms by electron stripping through absorption of a photon from a laser. The design of this diagnostic is presented with the corresponding simulation of the expected performance. A prototype operated without plasma has provided CRDS reference signals,more » design validation, and results concerning the signal-to-noise ratio.« less

An infrared sky model based on the IRAS point source data

NASA Technical Reports Server (NTRS)

Cohen, Martin; Walker, Russell; Wainscoat, Richard; Volk, Kevin; Walker, Helen; Schwartz, Deborah

1990-01-01

A detailed model for the infrared point source sky is presented that comprises geometrically and physically realistic representations of the galactic disk, bulge, spheroid, spiral arms, molecular ring, and absolute magnitudes. The model was guided by a parallel Monte Carlo simulation of the Galaxy. The content of the galactic source table constitutes an excellent match to the 12 micrometer luminosity function in the simulation, as well as the luminosity functions at V and K. Models are given for predicting the density of asteroids to be observed, and the diffuse background radiance of the Zodiacal cloud. The model can be used to predict the character of the point source sky expected for observations from future infrared space experiments.

Separation of Betti Reaction Product Enantiomers: Absolute Configuration and Inhibition of Botulinum Neurotoxin A

DTIC Science & Technology

2011-03-01

of Betti Reaction Product Enantiomers : Absolute Configuration and Inhibition of Botulinum Neurotoxin A John H. Cardellina II,† Rebecca C. Vieira...observing sufficient resolution of the two enantiomers on a Chiralcel OD column to permit semipreparative purification of adequate quantities of (þ)-1...comparison of the botulinum neurotoxin serotype A (BoNT/A) inhibitory activity of the (þ) and () enantiomers of 1 was accomplished via an HPLC-based assay

Betaine synthesis from radioactive precursors in attached, water-stressed barley leaves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, A.D.; Scott, N.A.

1980-08-01

In wilted barley leaves, betaine accumulates at about 200 nanomoles per 10 centimeters leaf per day. Results with /sup 14/C-labeled precursors were qualitatively and quantitatively consistent with de novo synthesis of this betaine from serine via ethanolamine, choline, and betaine aldehyde and indicated that water stress may increase the activities of all steps in this pathway except the last. Doses (I micromole) of each /sup 14/C-labeled precursor were supplied as droplets to the tips of attached, 10-centimeter, second-leaf blades of turgid and wilted plants, and the incorporation of /sup 14/C into betaine was followed. From the rates of betaine labeling,more » estimates were made of the potential capacities (nanomoles per 10 centimeters leaf per day) for the methylation and oxidation steps. Labeling of betaine from absolute value /sup 14/C choline, absolute value /sup 14/C ethanolamine, and absolute value /sup 14/C serine was about 7- to 10-fold greater in leaves wilted for 2 days than in turgid leaves, whereas label from absolute value /sup 14/C betaine aldehyde appeared in betaine at about the same rate in both turgid and wilted leaves. In leaves wilted for 2 days, the potential capacities for converting absolute value /sup 14/C ethanolamine, absolute value /sup 14/C choline, and absolute value /sup 14/C betaine aldehyde to betaine all approached or exceeded the rate of betain accumulation (about 200 nanomoles per 10 centimeters leaf per day); in turgid leaves, only the potential for converting betaine aldehyde to betaine exceeded this rate. The rate of conversion of absolute value /sup 14/C ethanolamine to betaine increased 4-fold after 6 to 10 hours of wilting, which was soon enough to account for the onset of betaine accumulation.« less

Detection of radioactive particles offshore by γ-ray spectrometry Part I: Monte Carlo assessment of detection depth limits

NASA Astrophysics Data System (ADS)

Maučec, M.; de Meijer, R. J.; Rigollet, C.; Hendriks, P. H. G. M.; Jones, D. G.

2004-06-01

A joint research project between the British Geological Survey and Nuclear Geophysics Division of the Kernfysisch Versneller Instituut, Groningen, the Netherlands, was commissioned by the United Kingdom Atomic Energy Authority to establish the efficiency of a towed seabed γ-ray spectrometer for the detection of 137Cs-containing radioactive particles offshore Dounreay, Scotland. Using the MCNP code, a comprehensive Monte Carlo feasibility study was carried out to model various combinations of geological matrices, particle burial depth and lateral displacement, source activity and detector material. To validate the sampling and absolute normalisation procedures of MCNP for geometries including multiple (natural and induced) heterogeneous sources in environmental monitoring, a benchmark experiment was conducted. The study demonstrates the ability of seabed γ-ray spectrometry to locate radioactive particles offshore and to distinguish between γ count rate increases due to particles from those due to enhanced natural radioactivity. The information presented in this study will be beneficial for estimation of the inventory of 137Cs particles and their activity distribution and for the recovery of particles from the sea floor. In this paper, the Monte Carlo assessment of the detection limits is presented. The estimation of the required towing speed and acquisition times and their application to radioactive particle detection and discrimination offshore formed a supplementary part of this study.

Effect of Absolute From Hibiscus syriacus L. Flower on Wound Healing in Keratinocytes

PubMed Central

Yoon, Seok Won; Lee, Kang Pa; Kim, Do-Yoon; Hwang, Dae Il; Won, Kyung-Jong; Lee, Dae Won; Lee, Hwan Myung

2017-01-01

Background: Proliferation and migration of keratinocytes are essential for the repair of cutaneous wounds. Hibiscus syriacus L. has been used in Asian medicine; however, research on keratinocytes is inadequate. Objective: To establish the dermatological properties of absolute from Hibiscus syriacus L. flower (HSF) and to provide fundamental research for alternative medicine. Materials and Methods: We identified the composition of HSF absolute using gas chromatography-mass spectrometry analysis. We also examined the effect of HSF absolute in HaCaT cells using the XTT assay, Boyden chamber assay, sprout-out growth assay, and western blotting. We conducted an in-vivo wound healing assay in rat tail-skin. Results: Ten major active compounds were identified from HSF absolute. As determined by the XTT assay, Boyden chamber assay, and sprout-out growth assay results, HSF absolute exhibited similar effects as that of epidermal growth factor on the proliferation and migration patterns of keratinocytes (HaCaT cells), which were significantly increased after HSF absolute treatment. The expression levels of the phosphorylated signaling proteins relevant to proliferation, including extracellular signal-regulated kinase 1/2 (Erk 1/2) and Akt, were also determined by western blot analysis. Conclusion: These results of our in-vitro and ex-vivo studies indicate that HSF absolute induced cell growth and migration of HaCaT cells by phosphorylating both Erk 1/2 and Akt. Moreover, we confirmed the wound-healing effect of HSF on injury of the rat tail-skin. Therefore, our results suggest that HSF absolute is promising for use in cosmetics and alternative medicine. SUMMARY Hisbiscus syriacus L. flower absolute increases HaCaT cell migration and proliferation.Hisbiscus syriacus L. flower absolute regulates phosphorylation of ERK 1/2 and Akt in HaCaT cell.Treatment with Hisbiscus syriacus L. flower induced sprout outgrowth.The wound in the tail-skin of rat was reduced by Hisbiscus syriacus L. flower absolute Abbreviations used: HSF: Hibiscus syriacus L. flower, Erk 1/2: extracellular signal-regulated kinase 1/2, EGF: epidermal growth factor, GC/MS: gas chromatography-mass spectrometry, DMEM: dulbecco's modified eagle medium, FBS: fetal bovine serum, BSA: bovine serum albumin, p-Akt: phosphorylation of Akt, p-Erk 1/2: phosphorylation of Erk 1/2. PMID:28216888

Six New Polyketide Decalin Compounds from Mangrove Endophytic Fungus Penicillium aurantiogriseum 328#

PubMed Central

Ma, Yanhong; Li, Jing; Huang, Meixiang; Liu, Lan; Wang, Jun; Lin, Yongcheng

2015-01-01

Six new compounds with polyketide decalin ring, peaurantiogriseols A–F (1–6), along with two known compounds, aspermytin A (7), 1-propanone,3-hydroxy-1-(1,2,4a,5,6,7,8,8a-octahydro-2,5-dihydroxy-1,2,6-trimethyl-1-naphthalenyl) (8), were isolated from the fermentation products of mangrove endophytic fungus Penicillium aurantiogriseum 328#. Their structures were elucidated based on their structure analysis. The absolute configurations of compounds 1 and 2 were determined by 1H NMR analysis of their Mosher esters; the absolute configurations of 3–6 were determined by using theoretical calculations of electronic circular dichroism (ECD). Compounds 1–8 showed low inhibitory activity against human aldose reductase, no activity of inducing neurite outgrowth, nor antimicrobial activity. PMID:26473887

Status of use of lunar irradiance for on-orbit calibration

USGS Publications Warehouse

Stone, T.C.; Kieffer, H.H.; Anderson, J.M.; ,

2002-01-01

Routine observations of the Moon have been acquired by the Robotic Lunar Observatory (ROLO) for over four years. The ROLO instruments measure lunar radiance in 23 VNIR (Moon diameter ???500 pixels) and 9 SWIR (???250 pixels) passbands every month when the Moon is at phase angle less than 90 degrees. These are converted to exoatmospheric values at standard distances using an atmospheric extinction model based on observations of standard stars and a NIST-traceable absolute calibration source. Reduction of the stellar images also provides an independent pathway for absolute calibration. Comparison of stellar-based and lamp-based absolute calibrations of the lunar images currently shows unacceptably large differences. An analytic model of lunar irradiance as a function of phase angle and viewing geometry is derived from the calibrated lunar images. Residuals from models which fit hundreds of observations at each wavelength average less than 2%. Comparison with SeaWiFS observations over three years reveals a small quasi-periodic change in SeaWiFS responsivity that correlates with distance from the Sun for the first two years, then departs from this correlation.

Experimental benchmark of the NINJA code for application to the Linac4 H- ion source plasma

NASA Astrophysics Data System (ADS)

Briefi, S.; Mattei, S.; Rauner, D.; Lettry, J.; Tran, M. Q.; Fantz, U.

2017-10-01

For a dedicated performance optimization of negative hydrogen ion sources applied at particle accelerators, a detailed assessment of the plasma processes is required. Due to the compact design of these sources, diagnostic access is typically limited to optical emission spectroscopy yielding only line-of-sight integrated results. In order to allow for a spatially resolved investigation, the electromagnetic particle-in-cell Monte Carlo collision code NINJA has been developed for the Linac4 ion source at CERN. This code considers the RF field generated by the ICP coil as well as the external static magnetic fields and calculates self-consistently the resulting discharge properties. NINJA is benchmarked at the diagnostically well accessible lab experiment CHARLIE (Concept studies for Helicon Assisted RF Low pressure Ion sourcEs) at varying RF power and gas pressure. A good general agreement is observed between experiment and simulation although the simulated electron density trends for varying pressure and power as well as the absolute electron temperature values deviate slightly from the measured ones. This can be explained by the assumption of strong inductive coupling in NINJA, whereas the CHARLIE discharges show the characteristics of loosely coupled plasmas. For the Linac4 plasma, this assumption is valid. Accordingly, both the absolute values of the accessible plasma parameters and their trends for varying RF power agree well in measurement and simulation. At varying RF power, the H- current extracted from the Linac4 source peaks at 40 kW. For volume operation, this is perfectly reflected by assessing the processes in front of the extraction aperture based on the simulation results where the highest H- density is obtained for the same power level. In surface operation, the production of negative hydrogen ions at the converter surface can only be considered by specialized beam formation codes, which require plasma parameters as input. It has been demonstrated that this input can be provided reliably by the NINJA code.

Lack of active follow-up of cancer patients in Chennai, India: implications for population-based survival estimates

PubMed Central

Rama, Ranganathan; Shanta, Viswanathan

2008-01-01

Abstract Objective To measure the bias in absolute cancer survival estimates in the absence of active follow-up of cancer patients in developing countries. Methods Included in the study were all incident cases of the 10 most common cancers and corresponding subtypes plus all tobacco-related cancers not ranked among the top 10 that were registered in the population-based cancer registry in Chennai, India, during 1990–1999 and followed through 2001. Registered incident cases were first matched with those in the all-cause mortality database from the vital statistics division of the Corporation of Chennai. Unmatched incident cancer cases were then actively followed up to determine their survival status. Absolute survival was estimated by using an actuarial method and applying different assumptions regarding the survival status (alive/dead) of cases under passive and active follow-up. Findings Before active follow-up, matches between cases ranged from 20% to 66%, depending on the site of the primary tumour. Active follow-up of unmatched incident cases revealed that 15% to 43% had died by the end of the follow-up period, while the survival status of 4% to 38% remained unknown. Before active follow-up of cancer patients, 5-year absolute survival was estimated to be between 22% and 47% higher, than when conventional actuarial assumption methods were applied to cases that were lost to follow-up. The smallest survival estimates were obtained when cases lost to follow-up were excluded from the analysis. Conclusion Under the conditions that prevail in India and other developing countries, active follow-up of cancer patients yields the most reliable estimates of cancer survival rates. Passive case follow-up alone or applying standard methods to estimate survival is likely to result in an upward bias. PMID:18670662

Theoretical studies of tone noise from a fan rotor

NASA Technical Reports Server (NTRS)

Rao, G. V. R.; Chu, W. T.; Digumarthi, R. V.

1973-01-01

An analytical study was made of some possible rotor alone noise sources of dipole, quadrapole and monopole characters which generate discrete tone noise. Particular emphasis is given to the tone noise caused by fan inlet flow distortion and turbulence. Analytical models are developed to allow prediction of absolute levels. Experimental data measured on a small scale fan is presented which indicates inlet turbulence interaction with a fan rotor can be a source of tone noise. Predicted and measured tone noise for the small scale rotor are shown to be in reasonable agreement.

Update on the diagnostic radiologist employment market: findings through 2004.

PubMed

Saket, Daniel D; Nwanze, Chukwuemeka C; Maynard, C Douglas; Sunshine, Jonathan H; Forman, Howard P

2005-12-01

The objective of this article is to summarize the latest information concerning the diagnostic radiologist employment market. Three sources of data are presented and compared with previous data: vacancies in academic radiology departments as of July; the ratio of job listings to job seekers at a major placement service; and the number of positions advertised in Radiology and the American Journal of Roentgenology. Vacancies in academic radiology departments averaged 3.9 in 2004, down 29%, and decreased for all subspecialties as compared with 2001, but the number of vacancies remained very similar to that for 2003. Job listings per job seeker were 1.1 in 2004, stable over the past 2 years but at the lowest level since 1997. The overall number of positions advertised declined by 14% in 2003 compared with 2002 and by an additional 17% in 2004, reaching the lowest level since 1998. In 2004, 45.3% of positions advertised were academic. Comparing 2003-2004 with 2001-2002, all geographic regions exhibited absolute declines in advertisements except the Northeast, which showed a 1.5% increase. Absolute increases occurred for musculoskeletal and emergency radiology positions. Statistically significant proportional decreases occurred for general radiology, vascular/interventional radiology, and pediatric radiology. Three separate data sources confirm a substantial and broad-based multiyear decline in the strength of the demand for diagnostic radiologists, with some shifting in relative demand for subspecialties. It is not clear if the decrease continued in 2004 or if 2004 demand was similar to that of 2003. Data are relative and do not indicate the employment market is weak in absolute terms.

THE ACUTE EFFECTS OF CONCENTRIC VERSUS ECCENTRIC MUSCLE FATIGUE ON SHOULDER ACTIVE REPOSITIONING SENSE

PubMed Central

2017-01-01

Purpose/Background Shoulder proprioception is essential in the activities of daily living as well as in sports. Acute muscle fatigue is believed to cause a deterioration of proprioception, increasing the risk of injury. The purpose of this study was to evaluate if fatigue of the shoulder external rotators during eccentric versus concentric activity affects shoulder joint proprioception as determined by active reproduction of position. Study design Quasi-experimental trial. Methods Twenty-two healthy subjects with no recent history of shoulder pathology were randomly allocated to either a concentric or an eccentric exercise group for fatiguing the shoulder external rotators. Proprioception was assessed before and after the fatiguing protocol using an isokinetic dynamometer, by measuring active reproduction of position at 30 ° of shoulder external rotation, reported as absolute angular error. The fatiguing protocol consisted of sets of fifteen consecutive external rotator muscle contractions in either the concentric or eccentric action. The subjects were exercised until there was a 30% decline from the peak torque of the subjects’ maximal voluntary contraction over three consecutive muscle contractions. Results A one-way analysis of variance test revealed no statistical difference in absolute angular error (p > 0.05) between concentric and eccentric groups. Moreover, no statistical difference (p > 0.05) was found in absolute angular error between pre- and post-fatigue in either group. Conclusions Eccentric exercise does not seem to acutely affect shoulder proprioception to a larger extent than concentric exercise. Level of evidence 2b PMID:28515976

Absolute determination of copper and silver in ancient coins using 14 MeV neutrons

NASA Astrophysics Data System (ADS)

Chalouhi, Ch.; Hourani, E.; Loos, R.; Melki, S.

1982-09-01

A method for absolute determination of copper and silver in ancient coins is described. Activation analysis by 14 MeV neutrons is performed. In the experimental procedure emphasis is placed on corrections for neutrons and gamma attenuation. In the analytical procedure, a multi linear-regression calculation is used to separate different contributions to the 511 keV gamma peak. The precision in the absolute determination of Cu and Ag is better than 2% in recent coins of definite shapes, whereas it is a somewhat lower in ancient coins of irregular shapes. The method was applied to ancient coins provided by the Museum of the American University of Beirut. Overall consistency and suitability of the method were obtained.

Absolute calibration of Kodak Biomax-MS film response to x rays in the 1.5- to 8-keV energy range

NASA Astrophysics Data System (ADS)

Marshall, F. J.; Knauer, J. P.; Anderson, D.; Schmitt, B. L.

2006-10-01

The absolute response of Kodak Biomax-MS film to x rays in the range from 1.5- to 8-keV has been measured using a laboratory electron-beam generated x-ray source. The measurements were taken at specific line energies by using Bragg diffraction to produce monochromatic beams of x rays. Multiple exposures were taken on Biomax MS film up to levels exceeding optical densities of 2 as measured by a microdensitometer. The absolute beam intensity for each exposure was measured with a Si (Li) detector. Additional response measurements were taken with Kodak direct exposure film (DEF) so as to compare the results of this technique to previously published calibrations. The Biomax-MS results have been fitted to a semiempirical mathematical model (Knauer et al., these proceedings). Users of the model can infer absolute fluences from observed exposure levels at either interpolated or extrapolated energies. To summarize the results: Biomax MS has comparable sensitivity to DEF film below 3keV but has reduced sensitivity above 3keV (˜50%). The lower exposure results from thinner emulsion layers, designed for use with phosphor screens. The ease with which Biomax-MS can be used in place of DEF (same format film, same developing process, and comparable sensitivity) makes it a good replacement.

Absolute calibration of Kodak Biomax-MS film response to x rays in the 1.5- to 8-keV energy range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, F. J.; Knauer, J. P.; Anderson, D.

2006-10-15

The absolute response of Kodak Biomax-MS film to x rays in the range from 1.5- to 8-keV has been measured using a laboratory electron-beam generated x-ray source. The measurements were taken at specific line energies by using Bragg diffraction to produce monochromatic beams of x rays. Multiple exposures were taken on Biomax MS film up to levels exceeding optical densities of 2 as measured by a microdensitometer. The absolute beam intensity for each exposure was measured with a Si(Li) detector. Additional response measurements were taken with Kodak direct exposure film (DEF) so as to compare the results of this techniquemore » to previously published calibrations. The Biomax-MS results have been fitted to a semiempirical mathematical model (Knauer et al., these proceedings). Users of the model can infer absolute fluences from observed exposure levels at either interpolated or extrapolated energies. To summarize the results: Biomax MS has comparable sensitivity to DEF film below 3 keV but has reduced sensitivity above 3 keV ({approx}50%). The lower exposure results from thinner emulsion layers, designed for use with phosphor screens. The ease with which Biomax-MS can be used in place of DEF (same format film, same developing process, and comparable sensitivity) makes it a good replacement.« less

Prediction of Short-Distance Aerial Movement of Phakopsora pachyrhizi Urediniospores Using Machine Learning.

PubMed

Wen, L; Bowen, C R; Hartman, G L

2017-10-01

Dispersal of urediniospores by wind is the primary means of spread for Phakopsora pachyrhizi, the cause of soybean rust. Our research focused on the short-distance movement of urediniospores from within the soybean canopy and up to 61 m from field-grown rust-infected soybean plants. Environmental variables were used to develop and compare models including the least absolute shrinkage and selection operator regression, zero-inflated Poisson/regular Poisson regression, random forest, and neural network to describe deposition of urediniospores collected in passive and active traps. All four models identified distance of trap from source, humidity, temperature, wind direction, and wind speed as the five most important variables influencing short-distance movement of urediniospores. The random forest model provided the best predictions, explaining 76.1 and 86.8% of the total variation in the passive- and active-trap datasets, respectively. The prediction accuracy based on the correlation coefficient (r) between predicted values and the true values were 0.83 (P < 0.0001) and 0.94 (P < 0.0001) for the passive and active trap datasets, respectively. Overall, multiple machine learning techniques identified the most important variables to make the most accurate predictions of movement of P. pachyrhizi urediniospores short-distance.

Assessing the Uncertainties on Seismic Source Parameters: Towards Realistic Estimates of Moment Tensor Determinations

NASA Astrophysics Data System (ADS)

Magnoni, F.; Scognamiglio, L.; Tinti, E.; Casarotti, E.

2014-12-01

Seismic moment tensor is one of the most important source parameters defining the earthquake dimension and style of the activated fault. Moment tensor catalogues are ordinarily used by geoscientists, however, few attempts have been done to assess possible impacts of moment magnitude uncertainties upon their own analysis. The 2012 May 20 Emilia mainshock is a representative event since it is defined in literature with a moment magnitude value (Mw) spanning between 5.63 and 6.12. An uncertainty of ~0.5 units in magnitude leads to a controversial knowledge of the real size of the event. The possible uncertainty associated to this estimate could be critical for the inference of other seismological parameters, suggesting caution for seismic hazard assessment, coulomb stress transfer determination and other analyses where self-consistency is important. In this work, we focus on the variability of the moment tensor solution, highlighting the effect of four different velocity models, different types and ranges of filtering, and two different methodologies. Using a larger dataset, to better quantify the source parameter uncertainty, we also analyze the variability of the moment tensor solutions depending on the number, the epicentral distance and the azimuth of used stations. We endorse that the estimate of seismic moment from moment tensor solutions, as well as the estimate of the other kinematic source parameters, cannot be considered an absolute value and requires to come out with the related uncertainties and in a reproducible framework characterized by disclosed assumptions and explicit processing workflows.

Is an absolute level of cortical beta suppression required for proper movement? Magnetoencephalographic evidence from healthy aging.

PubMed

Heinrichs-Graham, Elizabeth; Wilson, Tony W

2016-07-01

Previous research has connected a specific pattern of beta oscillatory activity to proper motor execution, but no study to date has directly examined how resting beta levels affect motor-related beta oscillatory activity in the motor cortex. Understanding this relationship is imperative to determining the basic mechanisms of motor control, as well as the impact of pathological beta oscillations on movement execution. In the current study, we used magnetoencephalography (MEG) and a complex movement paradigm to quantify resting beta activity and movement-related beta oscillations in the context of healthy aging. We chose healthy aging as a model because preliminary evidence suggests that beta activity is elevated in older adults, and thus by examining older and younger adults we were able to naturally vary resting beta levels. To this end, healthy younger and older participants were recorded during motor performance and at rest. Using beamforming, we imaged the peri-movement beta event-related desynchronization (ERD) and extracted virtual sensors from the peak voxels, which enabled absolute and relative beta power to be assessed. Interestingly, absolute beta power during the pre-movement baseline was much stronger in older relative to younger adults, and older adults also exhibited proportionally large beta desynchronization (ERD) responses during motor planning and execution compared to younger adults. Crucially, we found a significant relationship between spontaneous (resting) beta power and beta ERD magnitude in both primary motor cortices, above and beyond the effects of age. A similar link was found between beta ERD magnitude and movement duration. These findings suggest a direct linkage between beta reduction during movement and spontaneous activity in the motor cortex, such that as spontaneous beta power increases, a greater reduction in beta activity is required to execute movement. We propose that, on an individual level, the primary motor cortices have an absolute threshold of beta power that must be reached in order to move, and that an inability to suppress beta power to this threshold results in an increase in movement duration. Copyright © 2016 Elsevier Inc. All rights reserved.

Neutron activation measurements over an extremely wide dynamic range (invited) (abstract)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnes, C.W.

1997-01-01

The DT program at the Tokamak Fusion Test Reactor (TFTR) created requirements on 14 MeV neutron measurements to measure from 10{sup 6} n/cm{sup 2} (for triton burnup and Ohmic tritium plasmas) to {gt}10{sup 12} n/cm{sup 2} (characteristic of {gt}10 MW DT plasmas) with an accuracy of 7% (one-sigma).1 To maintain an absolute calibration over this dynamic range with active neutron detectors required one to go from some absolute standard at one fluence level to a measurement at a much higher fluence. Maintaining accuracy requires an extremely linear set of measurements not systematically affected over this dynamic range. Neutron activation canmore » provide such linearity when care is taken with a number of effects such as gamma-ray detection efficiency and sample contamination.2 Absolutely calibrated neutron yield measurements using dosimetric (well-known cross section) reactions with thin (low-mass) elemental foils is be described. This technique makes the detector comparison to an absolute standard of gamma-ray activity correspond to all neutron fluences by reducing the sample mass while keeping the activation detectors operating in a linear counting mode; i.e., low count rates which minimize pileup effects. The International Thermonuclear Experimental Reactor is projected to have 1000 s burn durations at fluxes of few 10{sup 13} n/cm{sup 2}s, or more neutron fluence {ital per second} than entire TFTR discharges. Extrapolating neutron activation to these higher fluences will require yet more care. Some of the issues at such high fluences will be discussed.3 The National Ignition Facility (NIF) is projected to yield 10 MJ of fusion energy, or up to 10{sup 12} n/cm{sup 2} at the vacuum vessel wall, similar to TFTR DT conditions. It is expected that much interesting physics will be performed at yields far less than those from ignition, covering an even greater dynamic range than needed on TFTR. Thin foil techniques do not have the sensitivity required at low fluences.« less

Absolute photoionization cross section of the ethyl radical in the range 8-11.5 eV: synchrotron and vacuum ultraviolet laser measurements.

PubMed

Gans, Bérenger; Garcia, Gustavo A; Boyé-Péronne, Séverine; Loison, Jean-Christophe; Douin, Stéphane; Gaie-Levrel, François; Gauyacq, Dolores

2011-06-02

The absolute photoionization cross section of C(2)H(5) has been measured at 10.54 eV using vacuum ultraviolet (VUV) laser photoionization. The C(2)H(5) radical was produced in situ using the rapid C(2)H(6) + F → C(2)H(5) + HF reaction. Its absolute photoionization cross section has been determined in two different ways: first using the C(2)H(5) + NO(2) → C(2)H(5)O + NO reaction in a fast flow reactor, and the known absolute photoionization cross section of NO. In a second experiment, it has been measured relative to the known absolute photoionization cross section of CH(3) as a reference by using the CH(4) + F → CH(3) + HF and C(2)H(6) + F → C(2)H(5) + HF reactions successively. Both methods gave similar results, the second one being more precise and yielding the value: σ(C(2)H(5))(ion) = (5.6 ± 1.4) Mb at 10.54 eV. This value is used to calibrate on an absolute scale the photoionization curve of C(2)H(5) produced in a pyrolytic source from the C(2)H(5)NO(2) precursor, and ionized by the VUV beam of the DESIRS beamline at SOLEIL synchrotron facility. In this latter experiment, a recently developed ion imaging technique is used to discriminate the direct photoionization process from dissociative ionization contributions to the C(2)H(5)(+) signal. The imaging technique applied on the photoelectron signal also allows a slow photoelectron spectrum with a 40 meV resolution to be extracted, indicating that photoionization around the adiabatic ionization threshold involves a complex vibrational overlap between the neutral and cationic ground states, as was previously observed in the literature. Comparison with earlier photoionization studies, in particular with the photoionization yield recorded by Ruscic et al. is also discussed. © 2011 American Chemical Society

Towards absolute laser spectroscopic CO2 isotope ratio measurements

NASA Astrophysics Data System (ADS)

Anyangwe Nwaboh, Javis; Werhahn, Olav; Ebert, Volker

2017-04-01

Knowledge of isotope composition of carbon dioxide (CO2) in the atmosphere is necessary to identify sources and sinks of this key greenhouse gas. In the last years, laser spectroscopic techniques such as cavity ring-down spectroscopy (CRDS) and tunable diode laser absorption spectroscopy (TDLAS) have been shown to perform accurate isotope ratio measurements for CO2 and other gases like water vapour (H2O) [1,2]. Typically, isotope ratios are reported in literature referring to reference materials provided by e.g. the International Atomic Energy Agency (IAEA). However, there could be some benefit if field deployable absolute isotope ratio measurement methods were developed to address issues such as exhausted reference material like the Pee Dee Belemnite (PDB) standard. Absolute isotope ratio measurements would be particularly important for situations where reference materials do not even exist. Here, we present CRDS and TDLAS-based absolute isotope ratios (13C/12C ) in atmospheric CO2. We demonstrate the capabilities of the used methods by measuring CO2 isotope ratios in gas standards. We compare our results to values reported for the isotope certified gas standards. Guide to the expression of uncertainty in measurement (GUM) compliant uncertainty budgets on the CRDS and TDLAS absolute isotope ratio measurements are presented, and traceability is addressed. We outline the current impediments in realizing high accuracy absolute isotope ratio measurements using laser spectroscopic methods, propose solutions and the way forward. Acknowledgement Parts of this work have been carried out within the European Metrology Research Programme (EMRP) ENV52 project-HIGHGAS. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. References [1] B. Kühnreich, S. Wagner, J. C. Habig,·O. Möhler, H. Saathoff, V. Ebert, Appl. Phys. B 119:177-187 (2015). [2] E. Kerstel, L. Gianfrani, Appl. Phys. B 92, 439-449 (2008).

Alpha absolute power measurement in panic disorder with agoraphobia patients.

PubMed

de Carvalho, Marcele Regine; Velasques, Bruna Brandão; Freire, Rafael C; Cagy, Maurício; Marques, Juliana Bittencourt; Teixeira, Silmar; Rangé, Bernard P; Piedade, Roberto; Ribeiro, Pedro; Nardi, Antonio Egidio; Akiskal, Hagop Souren

2013-10-01

Panic attacks are thought to be a result from a dysfunctional coordination of cortical and brainstem sensory information leading to heightened amygdala activity with subsequent neuroendocrine, autonomic and behavioral activation. Prefrontal areas may be responsible for inhibitory top-down control processes and alpha synchronization seems to reflect this modulation. The objective of this study was to measure frontal absolute alpha-power with qEEG in 24 subjects with panic disorder and agoraphobia (PDA) compared to 21 healthy controls. qEEG data were acquired while participants watched a computer simulation, consisting of moments classified as "high anxiety"(HAM) and "low anxiety" (LAM). qEEG data were also acquired during two rest conditions, before and after the computer simulation display. We observed a higher absolute alpha-power in controls when compared to the PDA patients while watching the computer simulation. The main finding was an interaction between the moment and group factors on frontal cortex. Our findings suggest that the decreased alpha-power in the frontal cortex for the PDA group may reflect a state of high excitability. Our results suggest a possible deficiency in top-down control processes of anxiety reflected by a low absolute alpha-power in the PDA group while watching the computer simulation and they highlight that prefrontal regions and frontal region nearby the temporal area are recruited during the exposure to anxiogenic stimuli. © 2013 Elsevier B.V. All rights reserved.

Missing Rings, Synchronous Growth, and Ecological Disturbance in a 36-Year Pitch Pine (Pinus rigida) Provenance Study

Treesearch

Caroline Leland; John Hom; Nicholas Skowronski; F. Thomas Ledig; Paul J. Krusic; Edward R. Cook; Dario Martin-Benito; Javier Martin-Fernandez; Neil Pederson; Dusan Gomory

2016-01-01

Provenance studies are an increasingly important analog for understanding how trees adapted to particular climatic conditions might respond to climate change. Dendrochronological analysis can illuminate differences among trees from different seed sources in terms of absolute annual growth and sensitivity to external growth factors. We analyzed annual radial growth of...

How Should "Self-Regard" Be Treated in Moral Education

ERIC Educational Resources Information Center

Hu, Zhongping

2007-01-01

One of the main reasons of the fact that Chinese moral education could hardly get out of its predicament is that "self-regard" has been simply and unilaterally interpreted as the absolute opposite to morality, where "self-regard" is merely regarded as the source of "everything evil", and the fact that it is also the…

Precise Absolute Astrometry from the VLBA Imaging and Polarimetry Survey at 5 GHz

NASA Technical Reports Server (NTRS)

Petrov, L.; Taylor, G. B.

2011-01-01

We present accurate positions for 857 sources derived from the astrometric analysis of 16 eleven-hour experiments from the Very Long Baseline Array imaging and polarimetry survey at 5 GHz (VIPS). Among the observed sources, positions of 430 objects were not previously determined at milliarcsecond-level accuracy. For 95% of the sources the uncertainty of their positions ranges from 0.3 to 0.9 mas, with a median value of 0.5 mas. This estimate of accuracy is substantiated by the comparison of positions of 386 sources that were previously observed in astrometric programs simultaneously at 2.3/8.6 GHz. Surprisingly, the ionosphere contribution to group delay was adequately modeled with the use of the total electron content maps derived from GPS observations and only marginally affected estimates of source coordinates.

[A Quality Assurance (QA) System with a Web Camera for High-dose-rate Brachytherapy].

PubMed

Hirose, Asako; Ueda, Yoshihiro; Oohira, Shingo; Isono, Masaru; Tsujii, Katsutomo; Inui, Shouki; Masaoka, Akira; Taniguchi, Makoto; Miyazaki, Masayoshi; Teshima, Teruki

2016-03-01

The quality assurance (QA) system that simultaneously quantifies the position and duration of an (192)Ir source (dwell position and time) was developed and the performance of this system was evaluated in high-dose-rate brachytherapy. This QA system has two functions to verify and quantify dwell position and time by using a web camera. The web camera records 30 images per second in a range from 1,425 mm to 1,505 mm. A user verifies the source position from the web camera at real time. The source position and duration were quantified with the movie using in-house software which was applied with a template-matching technique. This QA system allowed verification of the absolute position in real time and quantification of dwell position and time simultaneously. It was evident from the verification of the system that the mean of step size errors was 0.31±0.1 mm and that of dwell time errors 0.1±0.0 s. Absolute position errors can be determined with an accuracy of 1.0 mm at all dwell points in three step sizes and dwell time errors with an accuracy of 0.1% in more than 10.0 s of the planned time. This system is to provide quick verification and quantification of the dwell position and time with high accuracy at various dwell positions without depending on the step size.

Precision absolute-value amplifier for a precision voltmeter

DOEpatents

Hearn, W.E.; Rondeau, D.J.

1982-10-19

Bipolar inputs are afforded by the plus inputs of first and second differential input amplifiers. A first gain determining resistor is connected between the minus inputs of the differential amplifiers. First and second diodes are connected between the respective minus inputs and the respective outputs of the differential amplifiers. First and second FETs have their gates connected to the outputs of the amplifiers, while their respective source and drain circuits are connected between the respective minus inputs and an output lead extending to a load resistor. The output current through the load resistor is proportional to the absolute value of the input voltage difference between the bipolar input terminals. A third differential amplifier has its plus input terminal connected to the load resistor. A second gain determining resistor is connected between the minus input of the third differential amplifier and a voltage source. A third FET has its gate connected to the output of the third amplifier. The source and drain circuit of the third transistor is connected between the minus input of the third amplifier and a voltage-frequency converter, constituting an output device. A polarity detector is also provided, comprising a pair of transistors having their inputs connected to the outputs of the first and second differential amplifiers. The outputs of the polarity detector are connected to gates which switch the output of the voltage-frequency converter between up and down counting outputs.

Precision absolute value amplifier for a precision voltmeter

DOEpatents

Hearn, William E.; Rondeau, Donald J.

1985-01-01

Bipolar inputs are afforded by the plus inputs of first and second differential input amplifiers. A first gain determining resister is connected between the minus inputs of the differential amplifiers. First and second diodes are connected between the respective minus inputs and the respective outputs of the differential amplifiers. First and second FETs have their gates connected to the outputs of the amplifiers, while their respective source and drain circuits are connected between the respective minus inputs and an output lead extending to a load resister. The output current through the load resister is proportional to the absolute value of the input voltage difference between the bipolar input terminals. A third differential amplifier has its plus input terminal connected to the load resister. A second gain determining resister is connected between the minus input of the third differential amplifier and a voltage source. A third FET has its gate connected to the output of the third amplifier. The source and drain circuit of the third transistor is connected between the minus input of the third amplifier and a voltage-frequency converter, constituting an output device. A polarity detector is also provided, comprising a pair of transistors having their inputs connected to the outputs of the first and second differential amplifiers. The outputs of the polarity detector are connected to gates which switch the output of the voltage-frequency converter between up and down counting outputs.

Performance assessment of the BEBIG MultiSource® high dose rate brachytherapy treatment unit

NASA Astrophysics Data System (ADS)

Palmer, Antony; Mzenda, Bongile

2009-12-01

A comprehensive system characterisation was performed of the Eckert & Ziegler BEBIG GmbH MultiSource® High Dose Rate (HDR) brachytherapy treatment unit with an 192Ir source. The unit is relatively new to the UK market, with the first installation in the country having been made in the summer of 2009. A detailed commissioning programme was devised and is reported including checks of the fundamental parameters of source positioning, dwell timing, transit doses and absolute dosimetry of the source. Well chamber measurements, autoradiography and video camera analysis techniques were all employed. The absolute dosimetry was verified by the National Physical Laboratory, UK, and compared to a measurement based on a calibration from PTB, Germany, and the supplied source certificate, as well as an independent assessment by a visiting UK centre. The use of the 'Krieger' dosimetry phantom has also been evaluated. Users of the BEBIG HDR system should take care to avoid any significant bend in the transfer tube, as this will lead to positioning errors of the source, of up to 1.0 mm for slight bends, 2.0 mm for moderate bends and 5.0 mm for extreme curvature (depending on applicators and transfer tube used) for the situations reported in this study. The reason for these errors and the potential clinical impact are discussed. Users should also note the methodology employed by the system for correction of transit doses, and that no correction is made for the initial and final transit doses. The results of this investigation found that the uncorrected transit doses lead to small errors in the delivered dose at the first dwell position, of up to 2.5 cGy at 2 cm (5.6 cGy at 1 cm) from a 10 Ci source, but the transit dose correction for other dwells was accurate within 0.2 cGy. The unit has been mechanically reliable, and source positioning accuracy and dwell timing have been reproducible, with overall performance similar to other existing HDR equipment. The unit is capable of high quality brachytherapy treatment delivery, taking the above factors into account.

Source apportionment of exposures to volatile organic compounds. I. Evaluation of receptor models using simulated exposure data

NASA Astrophysics Data System (ADS)

Miller, Shelly L.; Anderson, Melissa J.; Daly, Eileen P.; Milford, Jana B.

Four receptor-oriented source apportionment models were evaluated by applying them to simulated personal exposure data for select volatile organic compounds (VOCs) that were generated by Monte Carlo sampling from known source contributions and profiles. The exposure sources modeled are environmental tobacco smoke, paint emissions, cleaning and/or pesticide products, gasoline vapors, automobile exhaust, and wastewater treatment plant emissions. The receptor models analyzed are chemical mass balance, principal component analysis/absolute principal component scores, positive matrix factorization (PMF), and graphical ratio analysis for composition estimates/source apportionment by factors with explicit restriction, incorporated in the UNMIX model. All models identified only the major contributors to total exposure concentrations. PMF extracted factor profiles that most closely represented the major sources used to generate the simulated data. None of the models were able to distinguish between sources with similar chemical profiles. Sources that contributed <5% to the average total VOC exposure were not identified.

NOTE: A Monte Carlo study of dose rate distribution around the specially asymmetric CSM3-a 137Cs source

NASA Astrophysics Data System (ADS)

Pérez-Calatayud, J.; Lliso, F.; Ballester, F.; Serrano, M. A.; Lluch, J. L.; Limami, Y.; Puchades, V.; Casal, E.

2001-07-01

The CSM3 137Cs type stainless-steel encapsulated source is widely used in manually afterloaded low dose rate brachytherapy. A specially asymmetric source, CSM3-a, has been designed by CIS Bio International (France) substituting the eyelet side seed with an inactive material in the CSM3 source. This modification has been done in order to allow a uniform dose level over the upper vaginal surface when this `linear' source is inserted at the top of the dome vaginal applicators. In this study the Monte Carlo GEANT3 simulation code, incorporating the source geometry in detail, was used to investigate the dosimetric characteristics of this special CSM3-a 137Cs brachytherapy source. The absolute dose rate distribution in water around this source was calculated and is presented in the form of an along-away table. Comparison of Sievert integral type calculations with Monte Carlo results are discussed.

Omega Dante soft x-ray power diagnostic component calibration at the National Synchrotron Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, K.M.; Weber, F.A.; Dewald, E.L.

2004-10-01

The Dante soft x-ray spectrometer, installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester, is a 12-channel filter-edge defined soft x-ray power diagnostic. It is used to measure the spectrally resolved, absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Dante component calibration efforts using two beam lines, U3C (50 eV-1 keV) and X8A (1-6 keV) at the National Synchrotron Light Source have been implemented to improve the accuracy of these measurements. We have calibrated metallic vacuum x-ray diodes, mirrors and filters.

Observation of pick-up ions in the solar wind: Evidence for the source of the anomalous cosmic ray component?

NASA Technical Reports Server (NTRS)

Hovestadt, D.; Moebius, E.; Klecker, B.; Scholer, M.; Gloeckler, G.; Ipavich, F. M.

1985-01-01

Singly ionized energetic helium has been observed in the solar wind by using the time of flight spectrometer SULEICA on the AMPTE/IRM satellite between September and December, 1984. The energy density spectrum shows a sharp cut off which is strongly correlated with the four fold solar wind bulk energy. The absolute flux of the He(+)ions of about 10000 ion/sq cm.s is present independent of the IPL magnetic field orientation. The most likely source is the neutral helium of the interstellar wind which is ionized by solar UV radiation. It is suggested that these particles represent the source of the anomalous cosmic ray component.

The effects of knee direction, physical activity and age on knee joint position sense.

PubMed

Relph, Nicola; Herrington, Lee

2016-06-01

Previous research has suggested a decline in knee proprioception with age. Furthermore, regular participation in physical activity may improve proprioceptive ability. However, there is no large scale data on uninjured populations to confirm these theories. The aim of this study was to provide normative knee joint position data (JPS) from healthy participants aged 18-82years to evaluate the effects of age, physical activity and knee direction. A sample of 116 participants across five age groups was used. The main outcome measures were knee JPS absolute error scores into flexion and extension, Tegner activity levels and General Practitioner Physical Activity Questionnaire results. Absolute error scores in to knee flexion were 3.6°, 3.9°, 3.5°, 3.7° and 3.1° and knee extension were 2.7°, 2.5°, 2.9°, 3.4° and 3.9° for ages 15-29, 30-44, 45-59, 60-74 and 75 years old respectively. Knee extension and flexion absolute error scores were significantly different when age group data were pooled. There was a significant effect of age and activity level on joint position sense into knee extension. Age and lower Tegner scores were also negatively correlated to joint position sense into knee extension. The results provide some evidence for a decline in knee joint position sense with age. Further, active populations may have heightened static proprioception compared to inactive groups. Normative knee joint position sense data is provided and may be used by practitioners to identify patients with reduced proprioceptive ability. Copyright © 2016 Elsevier B.V. All rights reserved.

Status of the KATRIN experiment and prospects to search for keV-mass sterile neutrinos in tritium β-decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mertens, Susanne

In this contribution the current status and future perspectives of the Karlsruhe Tritium Neutrino (KATRIN) Experiment are presented. The prime goal of this single β-decay experiment is to probe the absolute neutrino mass scale with a sensitivity of 200 meV (90% CL). We discuss first results of the recent main spectrometer commissioning measurements, successfully verifying the spectrometer’s basic vacuum, transmission and background properties. We also discuss the prospects of making use of the KATRIN tritium source, to search for sterile neutrinos in the multi-keV mass range constituting a classical candidate for Warm Dark Matter. Due to the very high sourcemore » luminosity, a statistical sensitivity down to active-sterile mixing angles of sin² θ < 1 · 10⁻⁷ (90% CL) could be reached.« less

Status of the KATRIN experiment and prospects to search for keV-mass sterile neutrinos in tritium β-decay

DOE PAGES

Mertens, Susanne

2015-03-24

In this contribution the current status and future perspectives of the Karlsruhe Tritium Neutrino (KATRIN) Experiment are presented. The prime goal of this single β-decay experiment is to probe the absolute neutrino mass scale with a sensitivity of 200 meV (90% CL). We discuss first results of the recent main spectrometer commissioning measurements, successfully verifying the spectrometer’s basic vacuum, transmission and background properties. We also discuss the prospects of making use of the KATRIN tritium source, to search for sterile neutrinos in the multi-keV mass range constituting a classical candidate for Warm Dark Matter. Due to the very high sourcemore » luminosity, a statistical sensitivity down to active-sterile mixing angles of sin² θ < 1 · 10⁻⁷ (90% CL) could be reached.« less

Comparison of cytotoxicity and genotoxicity induced by the extracts of methanol and gasoline engine exhausts.

PubMed

Zhang, Zunzhen; Che, Wangjun; Liang, Ying; Wu, Mei; Li, Na; Shu, Ya; Liu, Fang; Wu, Desheng

2007-09-01

Gasoline engine exhaust has been considered a major source of air pollution in China, and methanol is considered as a potential substitute for gasoline fuel. In this study, the genotoxicity and cytotoxicity of organic extracts of condensate, particulate matters (PM) and semivolatile organic compounds (SVOC) of gasoline and absolute methanol engine exhaust were examined by using MTT assay, micronucleus assay, comet assay and Ames test. The results have showed that gasoline engine exhaust exhibited stronger cytotoxicity to human lung carcinoma cell lines (A549 cell) than methanol engine exhaust. Furthermore, gasoline engine exhaust increased micronucleus formation, induced DNA damage in A549 cells and increased TA98 revertants in the presence of metabolic activating enzymes in a concentration-dependent manner. In contrast, methanol engine exhaust failed to exhibit these adverse effects. The results suggest methanol may be used as a cleaner fuel for automobile.

The Marine Sponge, Diacarnus bismarckensis, as a Source of Peroxiterpene Inhibitors of Trypanosoma brucei, the Causative Agent of Sleeping Sickness

PubMed Central

Rubio, Brent K.; Tenney, Karen; Ang, Kean-Hooi; Abdulla, Maha; Arkin, Michelle; McKerrow, James H.; Crews, Phillip

2009-01-01

Human African trypanosomiasis (HAT), also known as African sleeping sickness, is a neglected tropical disease with inadequate therapeutic options. We have launched a collaborative new lead discovery venture using our repository of extracts and natural product compounds as input into our growth inhibition primary screen against Trypanosoma brucei. Careful evaluation of the spectral data of the natural products and derivatives allowed for the elucidation of the absolute configuration (using the modified Mosher’s method) of two new peroxiterpenes: (+)-muqubilone B (1a) and (−)-ent-muqubilone (3a). Five known compounds were also isolated: (+)-sigmosceptrellin A (4a), (+)-sigmosceptrellin A methyl ester (4b), (−)-sigmosceptrellin B (5), (+)-epi-muqubillin A (6) and (−)-epi-nuapapuin B methyl ester (7). The isolated peroxiterpenes demonstrated activities in the range from IC50 = 0.2 – 2 μg/mL. PMID:19159277

Reader variability in breast density estimation from full-field digital mammograms: the effect of image postprocessing on relative and absolute measures.

PubMed

Keller, Brad M; Nathan, Diane L; Gavenonis, Sara C; Chen, Jinbo; Conant, Emily F; Kontos, Despina

2013-05-01

Mammographic breast density, a strong risk factor for breast cancer, may be measured as either a relative percentage of dense (ie, radiopaque) breast tissue or as an absolute area from either raw (ie, "for processing") or vendor postprocessed (ie, "for presentation") digital mammograms. Given the increasing interest in the incorporation of mammographic density in breast cancer risk assessment, the purpose of this study is to determine the inherent reader variability in breast density assessment from raw and vendor-processed digital mammograms, because inconsistent estimates could to lead to misclassification of an individual woman's risk for breast cancer. Bilateral, mediolateral-oblique view, raw, and processed digital mammograms of 81 women were retrospectively collected for this study (N = 324 images). Mammographic percent density and absolute dense tissue area estimates for each image were obtained from two radiologists using a validated, interactive software tool. The variability of interreader agreement was not found to be affected by the image presentation style (ie, raw or processed, F-test: P > .5). Interreader estimates of relative and absolute breast density are strongly correlated (Pearson r > 0.84, P < .001) but systematically different (t-test, P < .001) between the two readers. Our results show that mammographic density may be assessed with equal reliability from either raw or vendor postprocessed images. Furthermore, our results suggest that the primary source of density variability comes from the subjectivity of the individual reader in assessing the absolute amount of dense tissue present in the breast, indicating the need to use standardized tools to mitigate this effect. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

Studies of Secondary Melanoma on C57BL/6J Mouse Liver Using 1H NMR Metabolomics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Ju; Isern, Nancy G.; Burton, Sarah D.

2013-10-31

NMR metabolomics, consisting of solid state high resolution (hr) magic angle spinning (MAS) 1H NMR (1H hr-MAS), liquid state high resolution 1H-NMR, and principal components analysis (PCA) has been used to study secondary metastatic B16-F10 melanoma in C57BL/6J mouse liver . The melanoma group can be differentiated from its control group by PCA analysis of the absolute concentrations or by the absolute peak intensities of metabolites from either 1H hr-MAS NMR data on intact liver tissues or liquid state 1H-NMR spectra on liver tissue extracts. In particular, we found that the absolute concentrations of alanine, glutamate, creatine, creatinine, fumarate andmore » cholesterol are elevated in the melanoma group as compared to controls, while the absolute concentrations of succinate, glycine, glucose, and the family of linear lipids including long chain fatty acids, total choline and acylglycerol are decreased. The ratio of glycerophosphocholine to phosphocholine is increased by about 1.5 fold in the melanoma group, while the absolute concentration of total choline is actually lower in melanoma mice. These results suggest the following picture in secondary melanoma metastasis: Linear lipid levels are decreased by beta oxidation in the melanoma group, which contributes to an increase in the synthesis of cholesterol, and also provides an energy source input for TCA cycle. These findings suggest a link between lipid oxidation, the TCA cycle and the hypoxia-inducible factors (HIF) signal pathway in tumor metastases. Thus this study indicates that the metabolic profile derived from NMR analysis can provide a valuable bio-signature of malignancy and cell hypoxia in metastatic melanoma.« less

Unilateral lower limb suspension does not mimic bed rest or spaceflight effects on human muscle fiber function

NASA Technical Reports Server (NTRS)

Widrick, J. J.; Trappe, S. W.; Romatowski, J. G.; Riley, D. A.; Costill, D. L.; Fitts, R. H.

2002-01-01

We used Ca2+-activated skinned muscle fibers to test the hypothesis that unilateral lower leg suspension (ULLS) alters cross-bridge mechanisms of muscle contraction. Soleus and gastrocnemius biopsies were obtained from eight subjects before ULLS, immediately after 12 days of ULLS (post-0 h), and after 6 h of reambulation (post-6 h). Post-0 h soleus fibers expressing type I myosin heavy chain (MHC) showed significant reductions in diameter, absolute and specific peak Ca2+-activated force, unloaded shortening velocity, and absolute and normalized peak power. Fibers obtained from the gastrocnemius were less affected by ULLS, particularly fibers expressing fast MHC isoforms. Post-6 h soleus fibers produced less absolute and specific peak force than did post-0 h fibers, suggesting that reambulation after ULLS induced cell damage. Like bed rest and spaceflight, ULLS primarily affects soleus over gastrocnemius fibers. However, in contrast to these other models, slow soleus fibers obtained after ULLS showed a decrease in unloaded shortening velocity and a greater reduction in specific force.

Radiometric calibration of an airborne multispectral scanner. [of Thematic Mapper Simulator

NASA Technical Reports Server (NTRS)

Markham, Brian L.; Ahmad, Suraiya P.; Jackson, Ray D.; Moran, M. S.; Biggar, Stuart F.; Gellman, David I.; Slater, Philip N.

1991-01-01

The absolute radiometric calibration of the NS001 Thematic Mapper Simulator reflective channels was examined based on laboratory tests and in-flight comparisons to ground measurements. The NS001 data are calibrated in-flight by reference to the NS001 internal integrating sphere source. This source's power supply or monitoring circuitry exhibited greater instability in-flight during 1988-1989 than in the laboratory. Extrapolating laboratory behavior to in-flight data resulted in 7-20 percent radiance errors relative to ground measurements and atmospheric modeling. Assuming constancy in the source's output between laboraotry and in-flight resulted in generally smaller errors. Upgrades to the source's power supply and monitoring circuitry in 1990 improved its in-flight stability, though in-flight ground reflectance based calibration tests have not yet been performed.

Ultrahigh precision nonlinear reflectivity measurement system for saturable absorber mirrors with self-referenced fluence characterization.

PubMed

Orsila, Lasse; Härkönen, Antti; Hyyti, Janne; Guina, Mircea; Steinmeyer, Günter

2014-08-01

Measurement of nonlinear optical reflectivity of saturable absorber devices is discussed. A setup is described that enables absolute accuracy of reflectivity measurements better than 0.3%. A repeatability within 0.02% is shown for saturable absorbers with few-percent modulation depth. The setup incorporates an in situ knife-edge characterization of beam diameters, making absolute reflectivity estimations and determination of saturation fluences significantly more reliable. Additionally, several measures are discussed to substantially improve the reliability of the reflectivity measurements. At its core, the scheme exploits the limits of state-of-the-art digital lock-in technology but also greatly benefits from a fiber-based master-oscillator power-amplifier source, the use of an integrating sphere, and simultaneous comparison with a linear reflectivity standard.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morrison, H; Menon, G; Sloboda, R

The purpose of this study was to investigate the accuracy of radiochromic film calibration procedures used in external beam radiotherapy when applied to I-125 brachytherapy sources delivering higher doses, and to determine any necessary modifications to achieve similar accuracy in absolute dose measurements. GafChromic EBT3 film was used to measure radiation doses upwards of 35 Gy from 6 MV, 75 kVp and (∼28 keV) I-125 photon sources. A custom phantom was used for the I-125 irradiations to obtain a larger film area with nearly constant dose to reduce the effects of film heterogeneities on the optical density (OD) measurements. RGBmore » transmission images were obtained with an Epson 10000XL flatbed scanner, and calibration curves relating OD and dose using a rational function were determined for each colour channel and at each energy using a non-linear least square minimization method. Differences found between the 6 MV calibration curve and those for the lower energy sources are large enough that 6 MV beams should not be used to calibrate film for low-energy sources. However, differences between the 75 kVp and I-125 calibration curves were quite small; indicating that 75 kVp is a good choice. Compared with I-125 irradiation, this gives the advantages of lower type B uncertainties and markedly reduced irradiation time. To obtain high accuracy calibration for the dose range up to 35 Gy, two-segment piece-wise fitting was required. This yielded absolute dose measurement accuracy above 1 Gy of ∼2% for 75 kVp and ∼5% for I-125 seed exposures.« less

Development of a software package for solid-angle calculations using the Monte Carlo method

NASA Astrophysics Data System (ADS)

Zhang, Jie; Chen, Xiulian; Zhang, Changsheng; Li, Gang; Xu, Jiayun; Sun, Guangai

2014-02-01

Solid-angle calculations play an important role in the absolute calibration of radioactivity measurement systems and in the determination of the activity of radioactive sources, which are often complicated. In the present paper, a software package is developed to provide a convenient tool for solid-angle calculations in nuclear physics. The proposed software calculates solid angles using the Monte Carlo method, in which a new type of variance reduction technique was integrated. The package, developed under the environment of Microsoft Foundation Classes (MFC) in Microsoft Visual C++, has a graphical user interface, in which, the visualization function is integrated in conjunction with OpenGL. One advantage of the proposed software package is that it can calculate the solid angle subtended by a detector with different geometric shapes (e.g., cylinder, square prism, regular triangular prism or regular hexagonal prism) to a point, circular or cylindrical source without any difficulty. The results obtained from the proposed software package were compared with those obtained from previous studies and calculated using Geant4. It shows that the proposed software package can produce accurate solid-angle values with a greater computation speed than Geant4.

Systems analysis of a maize leaf developmental gradient redefines the current C4 model and provides candidates for regulation.

PubMed

Pick, Thea R; Bräutigam, Andrea; Schlüter, Urte; Denton, Alisandra K; Colmsee, Christian; Scholz, Uwe; Fahnenstich, Holger; Pieruschka, Roland; Rascher, Uwe; Sonnewald, Uwe; Weber, Andreas P M

2011-12-01

We systematically analyzed a developmental gradient of the third maize (Zea mays) leaf from the point of emergence into the light to the tip in 10 continuous leaf slices to study organ development and physiological and biochemical functions. Transcriptome analysis, oxygen sensitivity of photosynthesis, and photosynthetic rate measurements showed that the maize leaf undergoes a sink-to-source transition without an intermediate phase of C(3) photosynthesis or operation of a photorespiratory carbon pump. Metabolome and transcriptome analysis, chlorophyll and protein measurements, as well as dry weight determination, showed continuous gradients for all analyzed items. The absence of binary on-off switches and regulons pointed to a morphogradient along the leaf as the determining factor of developmental stage. Analysis of transcription factors for differential expression along the leaf gradient defined a list of putative regulators orchestrating the sink-to-source transition and establishment of C(4) photosynthesis. Finally, transcriptome and metabolome analysis, as well as enzyme activity measurements, and absolute quantification of selected metabolites revised the current model of maize C(4) photosynthesis. All data sets are included within the publication to serve as a resource for maize leaf systems biology.

Quantum-mechanical ab initio simulation of the Raman and IR spectra of Mn3Al2Si3O12 spessartine

NASA Astrophysics Data System (ADS)

Valenzano, Loredana; Meyer, Alessio; Demichelis, Raffaella; Civalleri, Bartolomeo; Dovesi, Roberto

2009-07-01

The IR and Raman spectra of spessartine garnet Mn3Al2Si3O12, are simulated with the periodic ab initio CRYSTAL code by adopting an all-electron Gaussian-type basis set and the B3LYP Hamiltonian. The frequencies of the 25 Raman active modes (3 of A 1 g , 8 of E g and 14 of F 2 g symmetry) and of the two sets of 17 F 1 u transverse-optical and longitudinal-optical frequencies are generated, as well as the IR oscillator strength. The agreement between calculated and experimental data is excellent: for the IR and Raman sets, the mean absolute difference overline{|Updelta|} is 4.0 and 6.8 cm-1, respectively. Isotopic substitution permits to highlight the Mn, Al and Si participation to the various zones of the spectrum. Graphical animation, available on the authors’ web-site ( http://www.crystal.unito.it/vibs/garnets/spessartine/ ), provides a very readable description of the movement of atoms and groups in each vibrational mode.

Systems Analysis of a Maize Leaf Developmental Gradient Redefines the Current C4 Model and Provides Candidates for Regulation[W][OA

PubMed Central

Pick, Thea R.; Bräutigam, Andrea; Schlüter, Urte; Denton, Alisandra K.; Colmsee, Christian; Scholz, Uwe; Fahnenstich, Holger; Pieruschka, Roland; Rascher, Uwe; Sonnewald, Uwe; Weber, Andreas P.M.

2011-01-01

We systematically analyzed a developmental gradient of the third maize (Zea mays) leaf from the point of emergence into the light to the tip in 10 continuous leaf slices to study organ development and physiological and biochemical functions. Transcriptome analysis, oxygen sensitivity of photosynthesis, and photosynthetic rate measurements showed that the maize leaf undergoes a sink-to-source transition without an intermediate phase of C3 photosynthesis or operation of a photorespiratory carbon pump. Metabolome and transcriptome analysis, chlorophyll and protein measurements, as well as dry weight determination, showed continuous gradients for all analyzed items. The absence of binary on–off switches and regulons pointed to a morphogradient along the leaf as the determining factor of developmental stage. Analysis of transcription factors for differential expression along the leaf gradient defined a list of putative regulators orchestrating the sink-to-source transition and establishment of C4 photosynthesis. Finally, transcriptome and metabolome analysis, as well as enzyme activity measurements, and absolute quantification of selected metabolites revised the current model of maize C4 photosynthesis. All data sets are included within the publication to serve as a resource for maize leaf systems biology. PMID:22186372

Effect of carbon sources on the aggregation of photo fermentative bacteria induced by L-cysteine for enhancing hydrogen production.

PubMed

Xie, Guo-Jun; Liu, Bing-Feng; Ding, Jie; Wang, Qilin; Ma, Chao; Zhou, Xu; Ren, Nan-Qi

2016-12-01

Poor flocculation of photo fermentative bacteria resulting in continuous biomass washout from photobioreactor is a critical challenge to achieve rapid and stable hydrogen production. In this work, the aggregation of Rhodopseudomonas faecalis RLD-53 was successfully developed in a photobioreactor and the effects of different carbon sources on hydrogen production and aggregation ability were investigated. Extracellular polymeric substances (EPS) production by R. faecalis RLD-53 cultivated using different carbon sources were stimulated by addition of L-cysteine. The absolute ζ potentials of R. faecalis RLD-53 were considerably decreased with addition of L-cysteine, and aggregation barriers based on DLVO dropped to 15-43 % of that in control groups. Thus, R. faecalis RLD-53 flocculated effectively, and aggregation abilities of strain RLD-53 cultivated with acetate, propionate, lactate and malate reached 29.35, 32.34, 26.07 and 24.86 %, respectively. In the continuous test, hydrogen-producing activity was also promoted and reached 2.45 mol H 2 /mol lactate, 3.87 mol H 2 /mol propionate and 5.10 mol H 2 /mol malate, respectively. Therefore, the aggregation of R. faecalis RLD-53 induced by L-cysteine is independent on the substrate types, which ensures the wide application of this technology to enhance hydrogen recovery from wastewater dominated by different organic substrates.

Restoration of the ASCA Source Position Accuracy

NASA Astrophysics Data System (ADS)

Gotthelf, E. V.; Ueda, Y.; Fujimoto, R.; Kii, T.; Yamaoka, K.

2000-11-01

We present a calibration of the absolute pointing accuracy of the Advanced Satellite for Cosmology and Astrophysics (ASCA) which allows us to compensate for a large error (up to 1') in the derived source coordinates. We parameterize a temperature dependent deviation of the attitude solution which is responsible for this error. By analyzing ASCA coordinates of 100 bright active galactic nuclei, we show that it is possible to reduce the uncertainty in the sky position for any given observation by a factor of 4. The revised 90% error circle radius is then 12", consistent with preflight specifications, effectively restoring the full ASCA pointing accuracy. Herein, we derive an algorithm which compensates for this attitude error and present an internet-based table to be used to correct post facto the coordinate of all ASCA observations. While the above error circle is strictly applicable to data taken with the on-board Solid-state Imaging Spectrometers (SISs), similar coordinate corrections are derived for data obtained with the Gas Imaging Spectrometers (GISs), which, however, have additional instrumental uncertainties. The 90% error circle radius for the central 20' diameter of the GIS is 24". The large reduction in the error circle area for the two instruments offers the opportunity to greatly enhance the search for X-ray counterparts at other wavelengths. This has important implications for current and future ASCA source catalogs and surveys.

Jasminum polyanthum Franch. as a natural source of (-)-methyl jasmonate: an alternative to the use of the synthetic standard.

PubMed

Blanch, Gracia Patricia; Flores, Gema; Caja, Maria del Mar; Ruiz del Castillo, Maria Luisa

2009-01-01

Methyl jasmonate (MJ) contains two chiral centres at C-3 and C-7 in its chemical structure, which implies that it can exist in four possible stereoisomeric forms, namely (+)-MJ, (-)-MJ, (+)-epiMJ and (-)-epiMJ. The absolute configuration of the two side chains of MJ affects the biological activity associated with this compound. To isolate pure (-)-MJ from a natural source, Jasminum polyanthum Franch., with the intention of increasing the knowledge about its biological properties, including its effect on the biosynthesis of plant metabolites. The method used was based on steam distillation extraction (SDE) as an extraction technique followed by high-performance liquid chromatography (HPLC) as a purification procedure. The HPLC flow-rate as well as the number of fractions accumulated were optimised to achieve the concentration and purity required. The employment of 0.3 mL/min as HPLC flow-rate and the accumulation of three HPLC fractions allowed the required enantiomeric purity (95%) and concentration (0.36 mg/L in each HPLC fraction) to efficiently obtain (-)-methyl jasmonate from Jasminum polyanthum Franch. to be achieved. The approach proposed may enable the properties and effect of pure (-)-MJ on plant responses to be studied. The use of a natural source to obtain (-)-MJ is presented as an alternative to the enantioselective synthesis and enantiomeric resolution from the standard racaemic mixture.

Measurement and source characteristics of carbonyl compounds in the atmosphere in Kaohsiung city, Taiwan.

PubMed

Wang, H K; Huang, C H; Chen, K S; Peng, Y P; Lai, C H

2010-07-15

The concentrations of eighteen atmospheric carbonyls species were measured by the LpDNPH-Cartridge and the microcomputer air sampling device at Nan-Chie (northern part) and Hsiung-Kong (southern part) sites in Kaohsiung city, southern Taiwan. These samples were then analyzed using a high performance liquid chromatography (HPLC). Measurements showed that the highest concentrations of carbonyls were formaldehyde (18.33 and 18.74 microg m(-3)) at the Nan-Chie and Hsiung-Kong site, followed by acetaldehyde (14.90 and 15.71 microg m(-3)). The concentrations of total carbonyls were higher at Hsiung-Kong site (66.96 microg m(-3)) than at Nan-Chie site (60.41 microg m(-3)). The concentrations of total carbonyls at Nan-Chie site (or Hsiung-Kong site) were 74.06 microg m(-3) (89.99 microg m(-3)) in summer and 37.14 microg m(-3) (46.50 microg m(-3)) in winter, due to the fact that photochemical activities are stronger in summer than in winter. The results of principal component analysis (PCA)/absolute principal component scores (APCS) suggest that the primary pollution sources at Nan-Chie were vehicle exhausts (gasoline and diesel engines), stationary emissions (petrochemical and food industry) and restaurant emissions, and the primary pollution sources at Hsiung-Kong were vehicle exhausts (gasoline and diesel engines), stationary emissions (metal assembly and petrochemical industry) and restaurant emissions. 2010 Elsevier B.V. All rights reserved.

Measuring the absolute deuterium-tritium neutron yield using the magnetic recoil spectrometer at OMEGA and the NIF.

PubMed

Casey, D T; Frenje, J A; Gatu Johnson, M; Séguin, F H; Li, C K; Petrasso, R D; Glebov, V Yu; Katz, J; Knauer, J P; Meyerhofer, D D; Sangster, T C; Bionta, R M; Bleuel, D L; Döppner, T; Glenzer, S; Hartouni, E; Hatchett, S P; Le Pape, S; Ma, T; MacKinnon, A; McKernan, M A; Moran, M; Moses, E; Park, H-S; Ralph, J; Remington, B A; Smalyuk, V; Yeamans, C B; Kline, J; Kyrala, G; Chandler, G A; Leeper, R J; Ruiz, C L; Cooper, G W; Nelson, A J; Fletcher, K; Kilkenny, J; Farrell, M; Jasion, D; Paguio, R

2012-10-01

A magnetic recoil spectrometer (MRS) has been installed and extensively used on OMEGA and the National Ignition Facility (NIF) for measurements of the absolute neutron spectrum from inertial confinement fusion implosions. From the neutron spectrum measured with the MRS, many critical implosion parameters are determined including the primary DT neutron yield, the ion temperature, and the down-scattered neutron yield. As the MRS detection efficiency is determined from first principles, the absolute DT neutron yield is obtained without cross-calibration to other techniques. The MRS primary DT neutron measurements at OMEGA and the NIF are shown to be in excellent agreement with previously established yield diagnostics on OMEGA, and with the newly commissioned nuclear activation diagnostics on the NIF.

The use of J-coupling as a sole criterion to assign the total absolute stereochemistry of new pyrrolidinone class synthetic analogs, derived from S-pyroglutamic acid

NASA Astrophysics Data System (ADS)

Kellici, Tahsin F.; Ntountaniotis, Dimitrios; Vanioti, Marianna; Golic Grdadolnik, Simona; Simcic, Mihael; Michas, Georgios; Moutevelis-Minakakis, Panagiota; Mavromoustakos, Thomas

2017-02-01

During the synthesis of new pyrrolidinone analogs possessing biological activity it is intriguing to assign their absolute stereochemistry as it is well known that drug potency is influenced by the stereochemistry. The combination of J-coupling information with theoretical results was used in order to establish their total stereochemistry when the chiral center of the starting material has known absolute stereochemistry. The J-coupling can be used as a sole criterion for novel synthetic analogs to identify the right stereochemistry. This approach is extremely useful especially in the case of analogs whose 2D NOESY spectra cannot provide this information. Few synthetic examples are given to prove the significance of this approach.

First identification of O,S-diethyl Thiocarbonate in Indian Cress absolute and odor evaluation of its synthesized homologues by GC-sniffing.

PubMed

Breme, Katharina; Guillamon, Nadine; Fernandez, Xavier; Tournayre, Pascal; Brevard, Hugues; Joulain, Daniel; Berdagué, Jean Louis; Meierhenrich, Uwe J

2009-03-25

Indian cress (Tropaeolum majus L.) absolute was studied by GC-olfactometry (VIDEO-Sniff method) in order to identify odor-active aroma compounds. Because of its fruity-sulfury odor note, a compound that has never been identified in plant extracts before stood out: O,S-diethyl thiocarbonate, present at 0.1% (percentage of the total GC/FID area) in the extract. GCxGC-TOFMS allowed for a clean mass spectrum to be obtained, and isolation by preparative GC followed by NMR studies allowed its identification. Here, we report on the first detection of O,S-diethyl thiocarbonate in Indian cress absolute by GC-olfactometry/VIDEO-Sniff and on its isolation and identification. The synthesis and odor evaluation of its homologues are presented.

Sources of organic nitrogen at the serpentinite-hosted Lost City hydrothermal field.

PubMed

Lang, S Q; Früh-Green, G L; Bernasconi, S M; Butterfield, D A

2013-03-01

The reaction of ultramafic rocks with water during serpentinization at moderate temperatures results in alkaline fluids with high concentrations of reduced chemical compounds such as hydrogen and methane. Such environments provide unique habitats for microbial communities capable of utilizing these reduced compounds in present-day and, possibly, early Earth environments. However, these systems present challenges to microbial communities as well, particularly due to high fluid pH and possibly the availability of essential nutrients such as nitrogen. Here we investigate the source and cycling of organic nitrogen at an oceanic serpentinizing environment, the Lost City hydrothermal field (30°N, Mid-Atlantic Ridge). Total hydrolizable amino acid (THAA) concentrations in the fluids range from 736 to 2300 nm and constitute a large fraction of the dissolved organic carbon (2.5-15.1%). The amino acid distributions, and the relative concentrations of these compounds across the hydrothermal field, indicate they most likely derived from chemolithoautotrophic production. Previous studies have identified the presence of numerous nitrogen fixation genes in the fluids and the chimneys. Organic nitrogen in actively venting chimneys has δ(15) N values as low as 0.1‰ which is compatible with biological nitrogen fixation. Total hydrolizable amino acids in the chimneys are enriched in (13) C by 2-7‰ compared to bulk organic matter. The distribution and absolute δ(13) C(THAA) values are compatible with a chemolithoautotrophic source, an attribution also supported by molar organic C/N ratios in most active chimneys (4.1-5.5) which are similar to those expected for microbial communities. In total, these data indicate nitrogen is readily available to microbial communities at Lost City. © 2013 Blackwell Publishing Ltd.

A New Tool for CME Arrival Time Prediction using Machine Learning Algorithms: CAT-PUMA

NASA Astrophysics Data System (ADS)

Liu, Jiajia; Ye, Yudong; Shen, Chenglong; Wang, Yuming; Erdélyi, Robert

2018-03-01

Coronal mass ejections (CMEs) are arguably the most violent eruptions in the solar system. CMEs can cause severe disturbances in interplanetary space and can even affect human activities in many aspects, causing damage to infrastructure and loss of revenue. Fast and accurate prediction of CME arrival time is vital to minimize the disruption that CMEs may cause when interacting with geospace. In this paper, we propose a new approach for partial-/full halo CME Arrival Time Prediction Using Machine learning Algorithms (CAT-PUMA). Via detailed analysis of the CME features and solar-wind parameters, we build a prediction engine taking advantage of 182 previously observed geo-effective partial-/full halo CMEs and using algorithms of the Support Vector Machine. We demonstrate that CAT-PUMA is accurate and fast. In particular, predictions made after applying CAT-PUMA to a test set unknown to the engine show a mean absolute prediction error of ∼5.9 hr within the CME arrival time, with 54% of the predictions having absolute errors less than 5.9 hr. Comparisons with other models reveal that CAT-PUMA has a more accurate prediction for 77% of the events investigated that can be carried out very quickly, i.e., within minutes of providing the necessary input parameters of a CME. A practical guide containing the CAT-PUMA engine and the source code of two examples are available in the Appendix, allowing the community to perform their own applications for prediction using CAT-PUMA.

Saturated fats: a perspective from lactation and milk composition.

PubMed

German, J Bruce; Dillard, Cora J

2010-10-01

For recommendations of specific targets for the absolute amount of saturated fat intake, we need to know what dietary intake is most appropriate? Changing agricultural production and processing to lower the relative quantities of macronutrients requires years to accomplish. Changes can have unintended consequences on diets and the health of subsets of the population. Hence, what are the appropriate absolute amounts of saturated fat in our diets? Is the scientific evidence consistent with an optimal intake of zero? If not, is it also possible that a finite intake of saturated fats is beneficial to overall health, at least to a subset of the population? Conclusive evidence from prospective human trials is not available, hence other sources of information must be considered. One approach is to examine the evolution of lactation, and the composition of milks that developed through millennia of natural selective pressure and natural selection processes. Mammalian milks, including human milk, contain 50% of their total fatty acids as saturated fatty acids. The biochemical formation of a single double bond converting a saturated to a monounsaturated fatty acid is a pathway that exists in all eukaryotic organisms and is active within the mammary gland. In the face of selective pressure, mammary lipid synthesis in all mammals continues to release a significant content of saturated fatty acids into milk. Is it possible that evolution of the mammary gland reveals benefits to saturated fatty acids that current recommendations do not consider?

Calibration strategies for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Gaug, Markus; Berge, David; Daniel, Michael; Doro, Michele; Förster, Andreas; Hofmann, Werner; Maccarone, Maria C.; Parsons, Dan; de los Reyes Lopez, Raquel; van Eldik, Christopher

2014-08-01

The Central Calibration Facilities workpackage of the Cherenkov Telescope Array (CTA) observatory for very high energy gamma ray astronomy defines the overall calibration strategy of the array, develops dedicated hardware and software for the overall array calibration and coordinates the calibration efforts of the different telescopes. The latter include LED-based light pulsers, and various methods and instruments to achieve a calibration of the overall optical throughput. On the array level, methods for the inter-telescope calibration and the absolute calibration of the entire observatory are being developed. Additionally, the atmosphere above the telescopes, used as a calorimeter, will be monitored constantly with state-of-the-art instruments to obtain a full molecular and aerosol profile up to the stratosphere. The aim is to provide a maximal uncertainty of 10% on the reconstructed energy-scale, obtained through various independent methods. Different types of LIDAR in combination with all-sky-cameras will provide the observatory with an online, intelligent scheduling system, which, if the sky is partially covered by clouds, gives preference to sources observable under good atmospheric conditions. Wide-field optical telescopes and Raman Lidars will provide online information about the height-resolved atmospheric extinction, throughout the field-of-view of the cameras, allowing for the correction of the reconstructed energy of each gamma-ray event. The aim is to maximize the duty cycle of the observatory, in terms of usable data, while reducing the dead time introduced by calibration activities to an absolute minimum.

Pre-service teachers' perceived value of general pedagogical knowledge for practice: Relations with epistemic beliefs and source beliefs.

PubMed

Merk, Samuel; Rosman, Tom; Rueß, Julia; Syring, Marcus; Schneider, Jürgen

2017-01-01

Pre-service teachers tend to devalue general pedagogical knowledge (GPK) as a valid source for deriving successful teaching practices. The present study investigated beliefs about knowledge sources and epistemic beliefs as predictors for students' perceived value of GPK. Three pre-registered hypotheses were tested. We expected beliefs that GPK originates from scientific sources to entail a devaluation of GPK (Hypothesis 1). Concerning epistemic beliefs, we expected absolute beliefs to positively, and multiplistic beliefs to negatively predict pre-service teachers' perceived practical value of GPK (Hypothesis 2). Finally, we expected relationships between epistemic beliefs and pre-service teachers' perceived practical value of GPK to be confounded by epistemic trustworthiness, perceived topic-specific consistency and topic-specific familiarity (Hypothesis 3). In a study using a split plot design, 365 pre-service teachers were presented with four texts on different educational research topics. For each topic, three text versions were constructed. Even though they were invariant in content, these versions varied in a way that the results were allegedly generated by a practitioner, an expert or by means of a scientific study. Unexpectedly, results showed that research findings allegedly generated by means of a scientific study were associated with a higher perceived value of (topic-specific) GPK for practice (Hypothesis 1). As expected, the perceived value of GPK for practice was predicted by topic-specific multiplism and domain-specific absolutism (Hypothesis 2). These predictive effects were confounded by expertise evaluations of the source and the consistency of prior beliefs with the presented research results (Hypothesis 3). In summary, our results suggest that source beliefs might not be responsible for the devaluation of GPK, but that beliefs on the nature and structure of GPK (i.e., epistemic beliefs) might play an even more important role in this respect. Implications for research and practice are discussed.

Pre-service teachers’ perceived value of general pedagogical knowledge for practice: Relations with epistemic beliefs and source beliefs

PubMed Central

Rosman, Tom; Rueß, Julia; Syring, Marcus; Schneider, Jürgen

2017-01-01

Pre-service teachers tend to devalue general pedagogical knowledge (GPK) as a valid source for deriving successful teaching practices. The present study investigated beliefs about knowledge sources and epistemic beliefs as predictors for students’ perceived value of GPK. Three pre-registered hypotheses were tested. We expected beliefs that GPK originates from scientific sources to entail a devaluation of GPK (Hypothesis 1). Concerning epistemic beliefs, we expected absolute beliefs to positively, and multiplistic beliefs to negatively predict pre-service teachers’ perceived practical value of GPK (Hypothesis 2). Finally, we expected relationships between epistemic beliefs and pre-service teachers’ perceived practical value of GPK to be confounded by epistemic trustworthiness, perceived topic-specific consistency and topic-specific familiarity (Hypothesis 3). In a study using a split plot design, 365 pre-service teachers were presented with four texts on different educational research topics. For each topic, three text versions were constructed. Even though they were invariant in content, these versions varied in a way that the results were allegedly generated by a practitioner, an expert or by means of a scientific study. Unexpectedly, results showed that research findings allegedly generated by means of a scientific study were associated with a higher perceived value of (topic-specific) GPK for practice (Hypothesis 1). As expected, the perceived value of GPK for practice was predicted by topic-specific multiplism and domain-specific absolutism (Hypothesis 2). These predictive effects were confounded by expertise evaluations of the source and the consistency of prior beliefs with the presented research results (Hypothesis 3). In summary, our results suggest that source beliefs might not be responsible for the devaluation of GPK, but that beliefs on the nature and structure of GPK (i.e., epistemic beliefs) might play an even more important role in this respect. Implications for research and practice are discussed. PMID:28934358

Physical activity and pregnancy: cardiovascular adaptations, recommendations and pregnancy outcomes.

PubMed

Melzer, Katarina; Schutz, Yves; Boulvain, Michel; Kayser, Bengt

2010-06-01

Regular physical activity is associated with improved physiological, metabolic and psychological parameters, and with reduced risk of morbidity and mortality. Current recommendations aimed at improving the health and well-being of nonpregnant subjects advise that an accumulation of > or =30 minutes of moderate physical activity should occur on most, if not all, days of the week. Regardless of the specific physiological changes induced by pregnancy, which are primarily developed to meet the increased metabolic demands of mother and fetus, pregnant women benefit from regular physical activity the same way as nonpregnant subjects. Changes in submaximal oxygen uptake (VO(2)) during pregnancy depend on the type of exercise performed. During maternal rest or submaximal weight-bearing exercise (e.g. walking, stepping, treadmill exercise), absolute maternal VO(2) is significantly increased compared with the nonpregnant state. The magnitude of change is approximately proportional to maternal weight gain. When pregnant women perform submaximal weight-supported exercise on land (e.g. level cycling), the findings are contradictory. Some studies reported significantly increased absolute VO(2), while many others reported unchanged or only slightly increased absolute VO(2) compared with the nonpregnant state. The latter findings may be explained by the fact that the metabolic demand of cycle exercise is largely independent of the maternal body mass, resulting in no absolute VO(2) alteration. Few studies that directly measured changes in maternal maximal VO(2) (VO(2max)) showed no difference in the absolute VO(2max) between pregnant and nonpregnant subjects in cycling, swimming or weight-bearing exercise. Efficiency of work during exercise appears to be unchanged during pregnancy in non-weight-bearing exercise. During weight-bearing exercise, the work efficiency was shown to be improved in athletic women who continue exercising and those who stop exercising during pregnancy. When adjusted for weight gain, the increased efficiency is maintained throughout the pregnancy, with the improvement being greater in exercising women. Regular physical activity has been proven to result in marked benefits for mother and fetus. Maternal benefits include improved cardiovascular function, limited pregnancy weight gain, decreased musculoskeletal discomfort, reduced incidence of muscle cramps and lower limb oedema, mood stability, attenuation of gestational diabetes mellitus and gestational hypertension. Fetal benefits include decreased fat mass, improved stress tolerance, and advanced neurobehavioural maturation. In addition, few studies that have directly examined the effects of physical activity on labour and delivery indicate that, for women with normal pregnancies, physical activity is accompanied with shorter labour and decreased incidence of operative delivery. However, a substantial proportion of women stop exercising after they discover they are pregnant, and only few begin participating in exercise activities during pregnancy. The adoption or continuation of a sedentary lifestyle during pregnancy may contribute to the development of certain disorders such as hypertension, maternal and childhood obesity, gestational diabetes, dyspnoea, and pre-eclampsia. In view of the global epidemic of sedentary behaviour and obesity-related pathology, prenatal physical activity was shown to be useful for the prevention and treatment of these conditions. Further studies with larger sample sizes are required to confirm the association between physical activity and outcomes of labour and delivery.

RXTE All-Sky Slew Survey. Catalog of X-Ray Sources at B Greater Than 10 deg

NASA Technical Reports Server (NTRS)

Revnivtsev, M.; Sazonov, S.; Jahoda, K.; Gilfanov, M.

2004-01-01

We report results of a serendipitous hard X-ray (3-20 keV), nearly all-sky (absolute value of b greater than l0 deg.) survey based on RXTE/PCA observations performed during satellite reorientations in 1996-2002. The survey is 80% (90%) complete to a 4(sigma) limiting flux of approx. = 1.8 (2.5) x 10(exp -l1) erg/s sq cm in the 3-20 keV band. The achieved sensitivity in the 3-8 keV and 8-20 keV subbands is similar to and an order of magnitude higher than that of the previously record HEAO-1 A1 and HEAO-1 A4 all-sky surveys, respectively. A combined 7 x 10(exp 3) sq. deg area of the sky is sampled to flux levels below l0(exp -11) erg/ s sq cm (3-20 keV). In total 294 sources are detected and localized to better than 1 deg. 236 (80%) of these can be confidently associated with a known astrophysical object; another 22 likely result from the superposition of 2 or 3 closely located known sources. 35 detected sources remain unidentified, although for 12 of these we report a likely soft X-ray counterpart from the ROSAT all-sky survey bright source catalog. Of the reliably identified sources, 63 have local origin (Milky Way, LMC or SMC), 64 are clusters of galaxies and 100 are active galactic nuclei (AGN). The fact that the unidentified X-ray sources have hard spectra suggests that the majority of them are AGN, including highly obscured ones (N(sub H) greater than l0(exp 23)/sq cm). For the first time we present a log N-log S diagram for extragalactic sources above 4 x l0(exp -12) erg/ s sq cm at 8-20 keV. Key words. cosmo1ogy:observations - diffuse radiation - X-rays general

Frequency domain near-infrared multiwavelength imager design using high-speed, direct analog-to-digital conversion

NASA Astrophysics Data System (ADS)

Zimmermann, Bernhard B.; Fang, Qianqian; Boas, David A.; Carp, Stefan A.

2016-01-01

Frequency domain near-infrared spectroscopy (FD-NIRS) has proven to be a reliable method for quantification of tissue absolute optical properties. We present a full-sampling direct analog-to-digital conversion FD-NIR imager. While we developed this instrument with a focus on high-speed optical breast tomographic imaging, the proposed design is suitable for a wide-range of biophotonic applications where fast, accurate quantification of absolute optical properties is needed. Simultaneous dual wavelength operation at 685 and 830 nm is achieved by concurrent 67.5 and 75 MHz frequency modulation of each laser source, respectively, followed by digitization using a high-speed (180 MS/s) 16-bit A/D converter and hybrid FPGA-assisted demodulation. The instrument supports 25 source locations and features 20 concurrently operating detectors. The noise floor of the instrument was measured at <1.4 pW/√Hz, and a dynamic range of 115+ dB, corresponding to nearly six orders of magnitude, has been demonstrated. Titration experiments consisting of 200 different absorption and scattering values were conducted to demonstrate accurate optical property quantification over the entire range of physiologically expected values.

Frequency domain near-infrared multiwavelength imager design using high-speed, direct analog-to-digital conversion

PubMed Central

Zimmermann, Bernhard B.; Fang, Qianqian; Boas, David A.; Carp, Stefan A.

2016-01-01

Abstract. Frequency domain near-infrared spectroscopy (FD-NIRS) has proven to be a reliable method for quantification of tissue absolute optical properties. We present a full-sampling direct analog-to-digital conversion FD-NIR imager. While we developed this instrument with a focus on high-speed optical breast tomographic imaging, the proposed design is suitable for a wide-range of biophotonic applications where fast, accurate quantification of absolute optical properties is needed. Simultaneous dual wavelength operation at 685 and 830 nm is achieved by concurrent 67.5 and 75 MHz frequency modulation of each laser source, respectively, followed by digitization using a high-speed (180  MS/s) 16-bit A/D converter and hybrid FPGA-assisted demodulation. The instrument supports 25 source locations and features 20 concurrently operating detectors. The noise floor of the instrument was measured at <1.4  pW/√Hz, and a dynamic range of 115+ dB, corresponding to nearly six orders of magnitude, has been demonstrated. Titration experiments consisting of 200 different absorption and scattering values were conducted to demonstrate accurate optical property quantification over the entire range of physiologically expected values. PMID:26813081

High intensity 5 eV atomic oxygen source and Low Earth Orbit (LEO) simulation facility

NASA Technical Reports Server (NTRS)

Cross, J. B.; Spangler, L. H.; Hoffbauer, M. A.; Archuleta, F. A.; Leger, Lubert; Visentine, James

1987-01-01

An atomic oxygen exposure facility has been developed for studies of material degradation. The goal of these studies is to provide design criteria and information for the manufacture of long life (20 to 30 years) construction materials for use in LEO. The studies that are being undertaken using the facility will provide: absolute reaction cross sections for use in engineering design problems; formulations of reaction mechanisms; and calibration of flight hardware (mass spectrometers, etc.) in order to directly relate experiments performed in LEO to ground based investigations. The facility consists of: (1) a CW laser sustained discharge source of O atoms having a variable energy up to 5 eV and an intensity between 10(15) and 10(17) O atoms s(-1) cm(-2); (2) an atomic beam formation and diagnostics system consisting of various stages of differential pumping, a mass spectrometer detector, and a time of flight analyzer; (3) a spinning rotor viscometer for absolute O atom flux measurements; and (4) provision for using the system for calibration of actual flight instruments. Surface analysis equipment is available for the characterization of material surfaces before and after exposure to O atoms.

Determination of photoionization cross-sections of different organic molecules using gas chromatography coupled to single-photon ionization (SPI) time-of-flight mass spectrometry (TOF-MS) with an electron-beam-pumped rare gas excimer light source (EBEL): influence of molecular structure and analytical implications.

PubMed

Eschner, Markus S; Zimmermann, Ralf

2011-07-01

This work describes a fast and reliable method for determination of photoionization cross-sections (PICS) by means of gas chromatography (GC) coupled to single-photon ionization mass spectrometry (SPI-MS). Photoionization efficiency (PIE) data for 69 substances was obtained at a photon energy of 9.8 ± 0.4 eV using an innovative electron-beam-pumped rare gas excimer light source (EBEL) filled with argon. The investigated analytes comprise 12 alkylbenzenes as well as 11 other substituted benzenes, 23 n-alkanes, ten polyaromatic hydrocarbons, seven aromatic heterocycles, and six polyaromatic heterocycles. Absolute PICS for each substance at 9.8 eV are calculated from the relative photoionization efficiencies of the compounds with respect to benzene, whose photoionization cross-section data is well known. Furthermore, a direct correlation between the type of benzene substituents and their absolute PICS is presented and discussed in depth. Finally, comparison of previously measured photoionization cross-sections for 20 substances shows good agreement with the data of the present work.

Tropical Gravity Wave Momentum Fluxes and Latent Heating Distributions

NASA Technical Reports Server (NTRS)

Geller, Marvin A.; Zhou, Tiehan; Love, Peter T.

2015-01-01

Recent satellite determinations of global distributions of absolute gravity wave (GW) momentum fluxes in the lower stratosphere show maxima over the summer subtropical continents and little evidence of GW momentum fluxes associated with the intertropical convergence zone (ITCZ). This seems to be at odds with parameterizations forGWmomentum fluxes, where the source is a function of latent heating rates, which are largest in the region of the ITCZ in terms of monthly averages. The authors have examined global distributions of atmospheric latent heating, cloud-top-pressure altitudes, and lower-stratosphere absolute GW momentum fluxes and have found that monthly averages of the lower-stratosphere GW momentum fluxes more closely resemble the monthly mean cloud-top altitudes rather than the monthly mean rates of latent heating. These regions of highest cloud-top altitudes occur when rates of latent heating are largest on the time scale of cloud growth. This, plus previously published studies, suggests that convective sources for stratospheric GW momentum fluxes, being a function of the rate of latent heating, will require either a climate model to correctly model this rate of latent heating or some ad hoc adjustments to account for shortcomings in a climate model's land-sea differences in convective latent heating.

A Location Method Using Sensor Arrays for Continuous Gas Leakage in Integrally Stiffened Plates Based on the Acoustic Characteristics of the Stiffener

PubMed Central

Bian, Xu; Li, Yibo; Feng, Hao; Wang, Jiaqiang; Qi, Lei; Jin, Shijiu

2015-01-01

This paper proposes a continuous leakage location method based on the ultrasonic array sensor, which is specific to continuous gas leakage in a pressure container with an integral stiffener. This method collects the ultrasonic signals generated from the leakage hole through the piezoelectric ultrasonic sensor array, and analyzes the space-time correlation of every collected signal in the array. Meanwhile, it combines with the method of frequency compensation and superposition in time domain (SITD), based on the acoustic characteristics of the stiffener, to obtain a high-accuracy location result on the stiffener wall. According to the experimental results, the method successfully solves the orientation problem concerning continuous ultrasonic signals generated from leakage sources, and acquires high accuracy location information on the leakage source using a combination of multiple sets of orienting results. The mean value of location absolute error is 13.51 mm on the one-square-meter plate with an integral stiffener (4 mm width; 20 mm height; 197 mm spacing), and the maximum location absolute error is generally within a ±25 mm interval. PMID:26404316

Acute and chronic T cell dynamics in the livers of simian immunodeficiency virus-infected macaques.

PubMed

Ahsan, Muhammad H; Gill, Amy F; Lackner, Andrew A; Veazey, Ronald S

2012-05-01

The mucosal immune system, particularly the gastrointestinal tract, is critically involved in the pathogenesis of human immunodeficiency virus (HIV) infection. Since the liver drains most of the substances coming from the intestinal tract, it may also play a role in the pathogenesis of HIV infection. Here we examined the percentages and absolute numbers of T cell subsets in the liver in normal and simian immunodeficiency virus (SIV)-infected macaques. Most of the T cells in the liver were CD8(+) memory cells, and most of these had an effector memory (CD95(+) CD28(-)) phenotype. CD4(+) T cells constituted approximately 20% of the liver T cell population, but the vast majority of these were also memory (CD95(+)) CCR5(+) cells, suggesting they were potential targets for viral infection. After SIV infection, CD4(+) T cells were markedly reduced, and increased proliferation and absolute numbers of CD8(+) T cells were detected in the liver. These data suggest that the liver is a major source of antigenic stimulation for promoting CD8(+) T cells and possibly a source for early CD4(+) T cell infection and destruction.

Acute and Chronic T Cell Dynamics in the Livers of Simian Immunodeficiency Virus-Infected Macaques

PubMed Central

Ahsan, Muhammad H.; Gill, Amy F.; Lackner, Andrew A.

2012-01-01

The mucosal immune system, particularly the gastrointestinal tract, is critically involved in the pathogenesis of human immunodeficiency virus (HIV) infection. Since the liver drains most of the substances coming from the intestinal tract, it may also play a role in the pathogenesis of HIV infection. Here we examined the percentages and absolute numbers of T cell subsets in the liver in normal and simian immunodeficiency virus (SIV)-infected macaques. Most of the T cells in the liver were CD8+ memory cells, and most of these had an effector memory (CD95+ CD28−) phenotype. CD4+ T cells constituted approximately 20% of the liver T cell population, but the vast majority of these were also memory (CD95+) CCR5+ cells, suggesting they were potential targets for viral infection. After SIV infection, CD4+ T cells were markedly reduced, and increased proliferation and absolute numbers of CD8+ T cells were detected in the liver. These data suggest that the liver is a major source of antigenic stimulation for promoting CD8+ T cells and possibly a source for early CD4+ T cell infection and destruction. PMID:22379078

Ice Nucleating Particle Properties in the Saharan Air Layer Close to the Dust Source

NASA Astrophysics Data System (ADS)

Boose, Y.; Garcia, I. M.; Rodríguez, S.; Linke, C.; Schnaiter, M.; Nickovic, S.; Lohmann, U.; Kanji, Z. A.; Sierau, B.

2015-12-01

In August 2013 and 2014 measurements of ice nucleating particle (INP) concentrations, aerosol particle size distributions, chemistry and fluorescence were conducted at the Izaña Atmospheric Observatory located at 2373 m asl on Tenerife, west off the African shore. During summer, the observatory is frequently within the Saharan Air Layer and thus often exposed to dust. Absolute INP concentrations and activated fractions at T=-40 to -15°C and RHi=100-150 % were measured. In this study, we discuss the in-situ measured INP properties with respect to changes in the chemical composition, the biological content, the source regions as well as transport pathways and thus aging processes of the dust aerosol. For the first time, ice crystal residues were also analyzed with regard to biological content by means of their autofluorescence signal close to a major dust source region. Airborne dust samples were collected with a cyclone for additional offline analysis in the laboratory under similar conditions as in the field. Both, in-situ and offline dust samples were chemically characterized using single-particle mass spectrometry. The DREAM8 dust model extended with dust mineral fractions was run to simulate meteorological and dust aerosol conditions for ice nucleation. Results show that the background aerosol at Izaña was dominated by carbonaceous particles, which were hardly ice-active under the investigated conditions. When Saharan dust was present, INP concentrations increased by up to two orders of magnitude even at water subsaturated conditions at T≤-25°C. Differences in the ice-activated fraction were found between different dust periods which seem to be linked to variations in the aerosol chemical composition (dust mixed with changing fractions of sea salt and differences in the dust aerosol itself). Furthermore, two biomass burning events in 2014 were identified which led to very low INP concentrations under the investigated temperature and relative humidity conditions.

Pharmacological activity and toxicity of some neurotropic agents under conditions of experimental hypodynamia

NASA Technical Reports Server (NTRS)

Kirichek, L. T.

1980-01-01

The indices of pharmacological range, risk coefficients, ED50, LD50, the size of the area of toxic activity, and maximal tolerated and absolute lethal doses were compared in hypodynamic mice. The pharmacological activity of the test neurotropic agents exhibiting a central action underwent change, but their toxicity remained unchanged.

Differences of serum interleukin-6 levels in normotensive and preeclampsia women

NASA Astrophysics Data System (ADS)

Lumbanraja, S. N.; Junitasari, R.; Pasaribu, H. P.

2018-03-01

Red cell distribution width (RDW) has been shown higher with the increase of inflammatory activity. As CD4 count is not available in all cities in Indonesia, RDW was hoped to be the next promising marker to predict the progression of HIV infection. This study aims to find the association of RDW with aCD4 count in HIV-positive reproductive women in Indonesia. It was a prospective cross sectional study enrolled 37 consented outpatients HIV-positive reproductive women in Haji Adam Malik General Hospital, Medan, Indonesia. A 10 mL blood was taken, separated into two tubes for complete blood count and CD4 count. Data were collected and analyzed with SPSS 19.Mean CD4 absolute was lowest in >14.5% RDW group but without statistical significance. By classify CD4 absolute count, CD4 absolute ≤350/mm3 showed significantly higher RDW than CD4 absolute >350/mm3 (13.98±2.10% vs 12.79±0.88% p=0.02). No correlation was between RDW and CD4 absolute, as well as, with CD4%.In conclusion, high RDW can be a promising marker to predict the low CD4 count in HIV-positive reproductive women within antiretroviral therapy.

Use of commercial and social sources of alcohol by underage drinkers: the role of pubertal timing.

PubMed

Storvoll, Elisabet E; Pape, Hilde; Rossow, Ingeborg

2008-01-01

We have explored whether alcohol use and procurement of alcohol from commercial and social sources vary with pubertal timing. A sub-sample of 9291 Norwegian minors (13-17 year-olds) was extracted from a nationwide school survey (response rate: 92%). Adolescents who had matured early (early developers, EDs) reported higher consumption and more alcohol-related harm than those who had matured late (late developers, LDs) or at the "normal" time (on time developers, ODs). Purchases from on-premise and off-premise outlets were much more important sources of alcohol for EDs than for ODs and LDs - both in relative and absolute terms. Moreover, EDs were somewhat more likely to obtain alcohol from social sources. Taken together, the findings indicate that adolescents who mature early have access to a larger variety of sources of alcohol than adolescents who mature later - which in turn may explain their increased level of drinking.

Comparison of measured and modelled negative hydrogen ion densities at the ECR-discharge HOMER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rauner, D.; Kurutz, U.; Fantz, U.

2015-04-08

As the negative hydrogen ion density n{sub H{sup −}} is a key parameter for the investigation of negative ion sources, its diagnostic quantification is essential in source development and operation as well as for fundamental research. By utilizing the photodetachment process of negative ions, generally two different diagnostic methods can be applied: via laser photodetachment, the density of negative ions is measured locally, but only relatively to the electron density. To obtain absolute densities, the electron density has to be measured additionally, which induces further uncertainties. Via cavity ring-down spectroscopy (CRDS), the absolute density of H{sup −} is measured directly,more » however LOS-averaged over the plasma length. At the ECR-discharge HOMER, where H{sup −} is produced in the plasma volume, laser photodetachment is applied as the standard method to measure n{sub H{sup −}}. The additional application of CRDS provides the possibility to directly obtain absolute values of n{sub H{sup −}}, thereby successfully bench-marking the laser photodetachment system as both diagnostics are in good agreement. In the investigated pressure range from 0.3 to 3 Pa, the measured negative hydrogen ion density shows a maximum at 1 to 1.5 Pa and an approximately linear response to increasing input microwave powers from 200 up to 500 W. Additionally, the volume production of negative ions is 0-dimensionally modelled by balancing H{sup −} production and destruction processes. The modelled densities are adapted to the absolute measurements of n{sub H{sup −}} via CRDS, allowing to identify collisions of H{sup −} with hydrogen atoms (associative and non-associative detachment) to be the dominant loss process of H{sup −} in the plasma volume at HOMER. Furthermore, the characteristic peak of n{sub H{sup −}} observed at 1 to 1.5 Pa is identified to be caused by a comparable behaviour of the electron density with varying pressure, as n{sub e} determines the volume production rate via dissociative electron attachment to vibrationally excited hydrogen molecules.« less

Landsat-7 ETM+ radiometric stability and absolute calibration

USGS Publications Warehouse

Markham, B.L.; Barker, J.L.; Barsi, J.A.; Kaita, E.; Thome, K.J.; Helder, D.L.; Palluconi, Frank Don; Schott, J.R.; Scaramuzza, Pat; ,

2002-01-01

Launched in April 1999, the Landsat-7 ETM+ instrument is in its fourth year of operation. The quality of the acquired calibrated imagery continues to be high, especially with respect to its three most important radiometric performance parameters: reflective band instrument stability to better than ??1%, reflective band absolute calibration to better than ??5%, and thermal band absolute calibration to better than ??0.6 K. The ETM+ instrument has been the most stable of any of the Landsat instruments, in both the reflective and thermal channels. To date, the best on-board calibration source for the reflective bands has been the Full Aperture Solar Calibrator, which has indicated changes of at most -1.8% to -2.0% (95% C.I.) change per year in the ETM+ gain (band 4). However, this change is believed to be caused by changes in the solar diffuser panel, as opposed to a change in the instrument's gain. This belief is based partially on ground observations, which bound the changes in gain in band 4 at -0.7% to +1.5%. Also, ETM+ stability is indicated by the monitoring of desert targets. These image-based results for four Saharan and Arabian sites, for a collection of 35 scenes over the three years since launch, bound the gain change at -0.7% to +0.5% in band 4. Thermal calibration from ground observations revealed an offset error of +0.31 W/m 2 sr um soon after launch. This offset was corrected within the U. S. ground processing system at EROS Data Center on 21-Dec-00, and since then, the band 6 on-board calibration has indicated changes of at most +0.02% to +0.04% (95% C.I.) per year. The latest ground observations have detected no remaining offset error with an RMS error of ??0.6 K. The stability and absolute calibration of the Landsat-7 ETM+ sensor make it an ideal candidate to be used as a reference source for radiometric cross-calibrating to other land remote sensing satellite systems.

Determination of air-loop volume and radon partition coefficient for measuring radon in water sample.

PubMed

Lee, Kil Yong; Burnett, William C

A simple method for the direct determination of the air-loop volume in a RAD7 system as well as the radon partition coefficient was developed allowing for an accurate measurement of the radon activity in any type of water. The air-loop volume may be measured directly using an external radon source and an empty bottle with a precisely measured volume. The partition coefficient and activity of radon in the water sample may then be determined via the RAD7 using the determined air-loop volume. Activity ratios instead of absolute activities were used to measure the air-loop volume and the radon partition coefficient. In order to verify this approach, we measured the radon partition coefficient in deionized water in the temperature range of 10-30 °C and compared the values to those calculated from the well-known Weigel equation. The results were within 5 % variance throughout the temperature range. We also applied the approach for measurement of the radon partition coefficient in synthetic saline water (0-75 ppt salinity) as well as tap water. The radon activity of the tap water sample was determined by this method as well as the standard RAD-H 2 O and BigBottle RAD-H 2 O. The results have shown good agreement between this method and the standard methods.

Terpecurcumins A-I from the rhizomes of Curcuma longa: absolute configuration and cytotoxic activity.

PubMed

Lin, Xionghao; Ji, Shuai; Li, Rui; Dong, Yinhui; Qiao, Xue; Hu, Hongbo; Yang, Wenzhi; Guo, Dean; Tu, Pengfei; Ye, Min

2012-12-28

Terpecurcumins A-I (1-9), together with three known analogues (10-12), were isolated from the rhizomes of Curcuma longa (turmeric). They were derived from the hybridization of curcuminoids and bisabolanes. The structures and absolute configurations of 1-9 were elucidated on the basis of extensive spectroscopic data analysis, including NMR and electronic circular dichroism spectra. The configuration of 10 was further confirmed by X-ray crystallography. A plausible biogenetic relationship for 1-12 is proposed. Compounds 4, 6, 7, 10, and 11 showed higher cytotoxic activities (IC(50), 10.3-19.4 μM) than curcumin (IC(50), 31.3-49.2 μM) against human cancer cell lines (A549, HepG2, and MDA-MB-231).

Resting-state beta and gamma activity in Internet addiction.

PubMed

Choi, Jung-Seok; Park, Su Mi; Lee, Jaewon; Hwang, Jae Yeon; Jung, Hee Yeon; Choi, Sam-Wook; Kim, Dai Jin; Oh, Sohee; Lee, Jun-Young

2013-09-01

Internet addiction is the inability to control one's use of the Internet and is related to impulsivity. Although a few studies have examined neurophysiological activity as individuals with Internet addiction engage in cognitive processing, no information on spontaneous EEG activity in the eyes-closed resting-state is available. We investigated resting-state EEG activities in beta and gamma bands and examined their relationships with impulsivity among individuals with Internet addiction and healthy controls. Twenty-one drug-naïve patients with Internet addiction (age: 23.33 ± 3.50 years) and 20 age-, sex-, and IQ-matched healthy controls (age: 22.40 ± 2.33 years) were enrolled in this study. Severity of Internet addiction was identified by the total score on Young's Internet Addiction Test. Impulsivity was measured with the Barratt Impulsiveness Scale-11 and a stop-signal task. Resting-state EEG during eyes closed was recorded, and the absolute/relative power of beta and gamma bands was analyzed. The Internet addiction group showed high impulsivity and impaired inhibitory control. The generalized estimating equation showed that the Internet-addiction group showed lower absolute power on the beta band than did the control group (estimate = -3.370, p < 0.01). On the other hand, the Internet-addiction group showed higher absolute power on the gamma band than did the control group (estimate = 0.434, p < 0.01). These EEG activities were significantly associated with the severity of Internet addiction as well as with the extent of impulsivity. The present study suggests that resting-state fast-wave brain activity is related to the impulsivity characterizing Internet addiction. These differences may be neurobiological markers for the pathophysiology of Internet addiction. Copyright © 2013 Elsevier B.V. All rights reserved.

Heterotrophic Cultivation of Cyanobacteria: Study of Effect of Exogenous Sources of Organic Carbon, Absolute Amount of Nutrients, and Stirring Speed on Biomass and Lipid Productivity

PubMed Central

Meireles dos Santos, Aline; Vieira, Karem Rodrigues; Basso Sartori, Rafaela; Meireles dos Santos, Alberto; Queiroz, Maria Isabel; Queiroz Zepka, Leila; Jacob-Lopes, Eduardo

2017-01-01

The production of bioproducts from cyanobacteria with techno-economic feasibility is a challenge to these biotechnological processes. The choice of low-cost raw materials is of great importance for the overall economy of bioprocesses, as they represent a significant percentage in the final cost of the product. The objective of this work was to study the operational parameters of cultivation (exogenous sources of organic carbon and absolute amount of nutrients) to optimize productivity in bioproducts by Aphanothece microscopica Nägeli, for further evaluation of stirring speed. The experiments were performed in a bubble column bioreactor, operating at 30°C, pH of 7.6, C/N ratio of 20, 100 mg/L of inoculum, continuous aeration of 1 volume of air per volume of culture per minute (VVM), and absence of light. The results indicate that absolute amounts of 5,000/250 using cassava starch resulted in improved system performance, reaching biomass productivity of 36.66 mg/L/h in parallel with lipid productivity of 6.65 mg/L/h. Finally, experiments with variation in stirring speed indicate that 200 rpm resulted in better average rate of substrate consumption (44.01 mg/L/h), in parallel to biomass productivity of 39.27 mg/L/h. However, the increase of stirring speed had a negative effect on lipid productivity of the process. The technological route developed indicates potential to production of biomass and bulk oil, as a result of the capacity of cyanobacteria to adapt their metabolism in varying culture conditions, which provides opportunities to modify, control, and thereby maximize the formation of targeted compounds. PMID:28265559

Utilization of coincidence criteria in absolute length measurements by optical interferometry in vacuum and air

NASA Astrophysics Data System (ADS)

Schödel, R.

2015-08-01

Traceability of length measurements to the international system of units (SI) can be realized by using optical interferometry making use of well-known frequencies of monochromatic light sources mentioned in the Mise en Pratique for the realization of the metre. At some national metrology institutes, such as Physikalisch-Technische Bundesanstalt (PTB) in Germany, the absolute length of prismatic bodies (e.g. gauge blocks) is realized by so-called gauge-block interference comparators. At PTB, a number of such imaging phase-stepping interference comparators exist, including specialized vacuum interference comparators, each equipped with three highly stabilized laser light sources. The length of a material measure is expressed as a multiple of each wavelength. The large number of integer interference orders can be extracted by the method of exact fractions in which the coincidence of the lengths resulting from the different wavelengths is utilized as a criterion. The unambiguous extraction of the integer interference orders is an essential prerequisite for correct length measurements. This paper critically discusses coincidence criteria and their validity for three modes of absolute length measurements: 1) measurements under vacuum in which the wavelengths can be identified with the vacuum wavelengths, 2) measurements under air in which the air refractive index is obtained from environmental parameters using an empirical equation, and 3) measurements under air in which the air refractive index is obtained interferometrically by utilizing a vacuum cell placed along the measurement pathway. For case 3), which corresponds to PTB’s Kösters-Comparator for long gauge blocks, the unambiguous determination of integer interference orders related to the air refractive index could be improved by about a factor of ten when an ‘overall dispersion value,’ suggested in this paper, is used as coincidence criterion.

A highly accurate absolute gravimetric network for Albania, Kosovo and Montenegro

NASA Astrophysics Data System (ADS)

Ullrich, Christian; Ruess, Diethard; Butta, Hubert; Qirko, Kristaq; Pavicevic, Bozidar; Murat, Meha

2016-04-01

The objective of this project is to establish a basic gravity network in Albania, Kosovo and Montenegro to enable further investigations in geodetic and geophysical issues. Therefore the first time in history absolute gravity measurements were performed in these countries. The Norwegian mapping authority Kartverket is assisting the national mapping authorities in Kosovo (KCA) (Kosovo Cadastral Agency - Agjencia Kadastrale e Kosovës), Albania (ASIG) (Autoriteti Shtetëror i Informacionit Gjeohapësinor) and in Montenegro (REA) (Real Estate Administration of Montenegro - Uprava za nekretnine Crne Gore) in improving the geodetic frameworks. The gravity measurements are funded by Kartverket. The absolute gravimetric measurements were performed from BEV (Federal Office of Metrology and Surveying) with the absolute gravimeter FG5-242. As a national metrology institute (NMI) the Metrology Service of the BEV maintains the national standards for the realisation of the legal units of measurement and ensures their international equivalence and recognition. Laser and clock of the absolute gravimeter were calibrated before and after the measurements. The absolute gravimetric survey was carried out from September to October 2015. Finally all 8 scheduled stations were successfully measured: there are three stations located in Montenegro, two stations in Kosovo and three stations in Albania. The stations are distributed over the countries to establish a gravity network for each country. The vertical gradients were measured at all 8 stations with the relative gravimeter Scintrex CG5. The high class quality of some absolute gravity stations can be used for gravity monitoring activities in future. The measurement uncertainties of the absolute gravity measurements range around 2.5 micro Gal at all stations (1 microgal = 10-8 m/s2). In Montenegro the large gravity difference of 200 MilliGal between station Zabljak and Podgorica can be even used for calibration of relative gravimeters. The complete basic gravimetric network of these countries will be tied to these absolute stations. In this presentation all the stations and results will be presented in detail and some special results analysed.

Enantiomeric Lignans and Neolignans from Phyllanthus glaucus: Enantioseparation and Their Absolute Configurations

NASA Astrophysics Data System (ADS)

Wu, Zhaodi; Lai, Yongji; Zhou, Lei; Wu, Ye; Zhu, Hucheng; Hu, Zhengxi; Yang, Jing; Zhang, Jinwen; Wang, Jianping; Luo, Zengwei; Xue, Yongbo; Zhang, Yonghui

2016-04-01

Eight pairs of enantiomeric neolignans, norlignans, and sesquineolignans (1a/1b-8a/8b), together with five known neolignans (9a/9b and 10-12), have been isolated from 70% acetone extract of the whole plants of Phyllanthus glaucus Wall. (Euphorbiaceae). The racemic or partial racemic mixtures were successfully separated by chiral HPLC using different types of chiral columns with various mobile phases. Their structures were elucidated on the basis of extensive spectroscopic data. The absolute configurations of 2a/2b were determined by computational analysis of their electronic circular dichroism (ECD) spectrum, and the absolute configurations of other isolates were ascertained by comparing their experimental ECD spectra and optical rotation values with those of structure-relevant compounds reported in literatures. Compounds 4a/4b featured unique sesquineolignan skeletons with a novel 7-4‧-epoxy-8‧-8‧‧/7‧-2‧‧ scaffold, consisting of an aryltetrahydronaphthalene and a dihydrobenzofuran moiety. The planar structures of compounds 2, 3, 7, and 8 were documented previously; however, their absolute configurations were established for the first time in this study. The antioxidant activities of 1a/1b-8a/8b were evaluated using DPPH free radical scavenging assay, and the results demonstrated that compounds 1b and 3b showed potent DPPH radical scavenging activities with IC50 values of 5.987 ± 1.212 and 9.641 ± 0.865 μg/mL, respectively.

Absolute measurements of the triplet-triplet annihilation rate and the charge-carrier recombination layer thickness in working polymer light-emitting diodes based on polyspirobifluorene

NASA Astrophysics Data System (ADS)

Rothe, C.; Al Attar, H. A.; Monkman, A. P.

2005-10-01

The triplet exciton densities in electroluminescent devices prepared from two polyspirobifluorene derivatives have been investigated by means of time-resolved transient triplet absorption as a function of optical and electrical excitation power at 20 K. Because of the low mobility of the triplet excitons at this temperature, the triplet generation profile within the active polymer layer is preserved throughout the triplet lifetime and as a consequence the absolute triplet-triplet annihilation efficiency is not homogeneously distributed but depends on position within the active layer. This then gives a method to measure the charge-carrier recombination layer after electrical excitation relative to the light penetration depth, which is identical to the triplet generation layer after optical excitation. With the latter being obtained from ellipsometry, an absolute value of 5 nm is found for the exciton formation layer in polyspirobifluorene devices. This layer increases to 11 nm if the balance between the electron and the hole mobility is improved by chemically modifying the polymer backbone. Also, and consistent with previous work, triplet diffusion is dispersive at low temperature. As a consequence of this, the triplet-triplet annihilation rate is not a constant in the classical sense but depends on the triplet excitation dose. At 20 K and for typical excitation doses, absolute values of the latter rate are of the order of 10-14cm3s-1 .

Estimation of lower flammability limits of C-H compounds in air at atmospheric pressure, evaluation of temperature dependence and diluent effect.

PubMed

Mendiburu, Andrés Z; de Carvalho, João A; Coronado, Christian R

2015-03-21

Estimation of the lower flammability limits of C-H compounds at 25 °C and 1 atm; at moderate temperatures and in presence of diluent was the objective of this study. A set of 120 C-H compounds was divided into a correlation set and a prediction set of 60 compounds each. The absolute average relative error for the total set was 7.89%; for the correlation set, it was 6.09%; and for the prediction set it was 9.68%. However, it was shown that by considering different sources of experimental data the values were reduced to 6.5% for the prediction set and to 6.29% for the total set. The method showed consistency with Le Chatelier's law for binary mixtures of C-H compounds. When tested for a temperature range from 5 °C to 100 °C, the absolute average relative errors were 2.41% for methane; 4.78% for propane; 0.29% for iso-butane and 3.86% for propylene. When nitrogen was added, the absolute average relative errors were 2.48% for methane; 5.13% for propane; 0.11% for iso-butane and 0.15% for propylene. When carbon dioxide was added, the absolute relative errors were 1.80% for methane; 5.38% for propane; 0.86% for iso-butane and 1.06% for propylene. Copyright © 2014 Elsevier B.V. All rights reserved.

Commercial golf glove effects on golf performance and forearm muscle activity.

PubMed

Sorbie, Graeme G; Darroch, Paul; Grace, Fergal M; Gu, Yaodong; Baker, Julien S; Ugbolue, Ukadike C

2017-01-01

The study aimed to determine whether or not commercial golf gloves influence performance variables and forearm muscle activity during golf play. Fifteen golfers participated in the laboratory based study, each performing 8 golf swings with a Driver and 7-iron whilst wearing a glove and 8 without wearing the glove. Club head speed, ball speed and absolute carry distance performance variables were calculated. Surface electromyography was recorded from the flexor digitorum superficialis and extensor carpi radialis brevis on both forearm muscles. Club head speed, ball speed and absolute carry distance was significantly higher when using the Driver with the glove in comparison to the Driver without the glove (p < 0.05). No significant differences were evident when using the 7-iron and no significant differences were displayed in muscle activity in either of the conditions. Findings from this study suggest that driving performance is improved when wearing a glove.

Cultural influences on neural substrates of attentional control.

PubMed

Hedden, Trey; Ketay, Sarah; Aron, Arthur; Markus, Hazel Rose; Gabrieli, John D E

2008-01-01

Behavioral research has shown that people from Western cultural contexts perform better on tasks emphasizing independent (absolute) dimensions than on tasks emphasizing interdependent (relative) dimensions, whereas the reverse is true for people from East Asian contexts. We assessed functional magnetic resonance imaging responses during performance of simple visuospatial tasks in which participants made absolute judgments (ignoring visual context) or relative judgments (taking visual context into account). In each group, activation in frontal and parietal brain regions known to be associated with attentional control was greater during culturally nonpreferred judgments than during culturally preferred judgments. Also, within each group, activation differences in these regions correlated strongly with scores on questionnaires measuring individual differences in culture-typical identity. Thus, the cultural background of an individual and the degree to which the individual endorses cultural values moderate activation in brain networks engaged during even simple visual and attentional tasks.

Healthcare-Related Financial Burden among Families in the U.S.: The Role of Childhood Activity Limitations and Income

PubMed Central

Witt, Whitney P.; Litzelman, Kristin; Mandic, Carmen G.; Wisk, Lauren E.; Hampton, John M.; Creswell, Paul D.; Gottlieb, Carissa A.; Gangnon, Ronald E.

2011-01-01

This study examined the impact of childhood activity limitations on family financial burden in the U.S. We used ten complete panels (1996-2006) of the Medical Expenditure Panel Survey (MEPS) to evaluate the burden of out-of-pocket healthcare expenditures for 17,857 families with children aged 0-17 years. Multivariate generalized linear models were used to examine the relationship between childhood activity limitation status and both absolute and relative financial burden. Families of children with limitations had higher absolute out-of-pocket healthcare expenditures than families of children without limitations ($594.36 higher; p<0.05), and were 54% more likely to experience relative burden (p<0.05). Substantial socioeconomic disparities in financial burden were observed. Policies are needed to enable these families to access appropriate and affordable healthcare services. PMID:21552342

Laser Truss Sensor for Segmented Telescope Phasing

NASA Technical Reports Server (NTRS)

Liu, Duncan T.; Lay, Oliver P.; Azizi, Alireza; Erlig, Herman; Dorsky, Leonard I.; Asbury, Cheryl G.; Zhao, Feng

2011-01-01

A paper describes the laser truss sensor (LTS) for detecting piston motion between two adjacent telescope segment edges. LTS is formed by two point-to-point laser metrology gauges in a crossed geometry. A high-resolution (<30 nm) LTS can be implemented with existing laser metrology gauges. The distance change between the reference plane and the target plane is measured as a function of the phase change between the reference and target beams. To ease the bandwidth requirements for phase detection electronics (or phase meter), homodyne or heterodyne detection techniques have been used. The phase of the target beam also changes with the refractive index of air, which changes with the air pressure, temperature, and humidity. This error can be minimized by enclosing the metrology beams in baffles. For longer-term (weeks) tracking at the micron level accuracy, the same gauge can be operated in the absolute metrology mode with an accuracy of microns; to implement absolute metrology, two laser frequencies will be used on the same gauge. Absolute metrology using heterodyne laser gauges is a demonstrated technology. Complexity of laser source fiber distribution can be optimized using the range-gated metrology (RGM) approach.

Absolute single-photoionization cross sections of Se 2 + : Experiment and theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Macaluso, D. A.; Aguilar, A.; Kilcoyne, A. L. D.

2015-12-28

Absolute single-photoionization cross-section measurements for Se 2+ ions were performed at the Advanced Light Source at Lawrence Berkeley National Laboratory using the merged-beams photo-ion technique. Measurements were made at a photon energy resolution of 24 ± 3 meV in the photon energy range 23.5-42.5 eV, spanning the ground state and low-lying metastable state ionization thresholds. Here, to clearly resolve the resonant structure near the ground-state threshold, high-resolution measurements were made from 30.0 to 31.9 eV at a photon energy resolution of 6.7 ± 0.7 meV. Numerous resonance features observed in the experimental spectra are assigned and their energies and quantummore » defects tabulated. The high-resolution cross-section measurements are compared with large-scale, state-of-the-art theoretical cross-section calculations obtained from the Dirac Coulomb R -matrix method. Suitable agreement is obtained over the entire photon energy range investigated. In conclusion, these results are an experimental determination of the absolute photoionization cross section of doubly ionized selenium and include a detailed analysis of the photoionization resonance spectrum of this ion.« less

Revised SNAP III Training Manual

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moss, Calvin Elroy; Gonzales, Samuel M.; Myers, William L.

The Shielded Neutron Assay Probe (SNAP) technique was developed to determine the leakage neutron source strength of a radioactive object. The original system consisted of an Eberline TM Mini-scaler and discrete neutron detector. The system was operated by obtaining the count rate with the Eberline TM instrument, determining the absolute efficiency from a graph, and calculating the neutron source strength by hand. In 2003 the SNAP III, shown in Figure 1, was designed and built. It required the operator to position the SNAP, and then measure the source-to-detector and detectorto- reflector distances. Next the operator entered the distance measurements andmore » started the data acquisition. The SNAP acquired the required count rate and then calculated and displayed the leakage neutron source strength (NSS). The original design of the SNAP III is described in SNAP III Training Manual (ER-TRN-PLN-0258, Rev. 0, January 2004, prepared by William Baird) This report describes some changes that have been made to the SNAP III. One important change is the addition of a LEMO connector to provide neutron detection output pulses for input to the MC-15. This feature is useful in active interrogation with a neutron generator because the MC-15 has the capability to only record data when it is not gated off by a pulse from the neutron generator. This avoids recording of a lot of data during the generator pulses that are not useful. Another change was the replacement of the infrared RS-232 serial communication output by a similar output via a 4-pin LEMO connector. The current document includes a more complete explanation of how to estimate the amount of moderation around a neutron-emitting source.« less

Approximate supernova remnant dynamics with cosmic ray production

NASA Technical Reports Server (NTRS)

Voelk, H. J.; Drury, L. O.; Dorfi, E. A.

1985-01-01

Supernova explosions are the most violent and energetic events in the galaxy and have long been considered probably sources of Cosmic Rays. Recent shock acceleration models treating the Cosmic Rays (CR's) as test particles nb a prescribed Supernova Remnant (SNR) evolution, indeed indicate an approximate power law momentum distribution f sub source (p) approximation p(-a) for the particles ultimately injected into the Interstellar Medium (ISM). This spectrum extends almost to the momentum p = 1 million GeV/c, where the break in the observed spectrum occurs. The calculated power law index approximately less than 4.2 agrees with that inferred for the galactic CR sources. The absolute CR intensity can however not be well determined in such a test particle approximation.

Modeling the source contribution of heavy metals in surficial sediment and analysis of their historical changes in the vertical sediments of a drinking water reservoir

NASA Astrophysics Data System (ADS)

Wang, Guoqiang; A, Yinglan; Jiang, Hong; Fu, Qing; Zheng, Binghui

2015-01-01

Increasing water pollution in developing countries poses a significant threat to environmental health and human welfare. Understanding the spatial distribution and apportioning the sources of pollution are important for the efficient management of water resources. In this study, ten types of heavy metals were detected during 2010-2013 for all ambient samples and point sources samples. A pollution assessment based on the surficial sediment dataset by Enrichment Factor (EF) showed the surficial sediment was moderately contaminated. A comparison of the multivariate approach (principle components analysis/absolute principle component score, PCA/APCS) and the chemical mass balance model (CMB) shows that the identification of sources and calculation of source contribution based on the CMB were more objective and acceptable when source profiles were known and source composition was complex. The results of source apportionment for surficial heavy metals, both from PCA/APCS and CMB model, showed that the natural background (30%) was the most dominant contributor to the surficial heavy metals, followed by mining activities (29%). The contribution percentage of the natural background was negatively related to the degree of contamination. The peak concentrations of many heavy metals (Cu, Ba, Fe, As and Hg) were found in the middle layer of sediment, which is most likely due to the result of development of industry beginning in the 1970s. However, the highest concentration of Pb appeared in the surficial sediment layer, which was most likely due to the sharp increase in the traffic volume. The historical analysis of the sources based on the CMB showed that mining and the chemical industry are stable sources for all of the sections. The comparing of change rates of source contribution versus years indicated that the composition of the materials in estuary site (HF1) is sensitive to the input from the land, whereas center site (HF4) has a buffering effect on the materials from the land through a series of complex movements. These results provide information for the development of improved pollution control strategies for the lakes and reservoirs.

Method of excess fractions with application to absolute distance metrology: wavelength selection and the effects of common error sources.

PubMed

Falaggis, Konstantinos; Towers, David P; Towers, Catherine E

2012-09-20

Multiwavelength interferometry (MWI) is a well established technique in the field of optical metrology. Previously, we have reported a theoretical analysis of the method of excess fractions that describes the mutual dependence of unambiguous measurement range, reliability, and the measurement wavelengths. In this paper wavelength, selection strategies are introduced that are built on the theoretical description and maximize the reliability in the calculated fringe order for a given measurement range, number of wavelengths, and level of phase noise. Practical implementation issues for an MWI interferometer are analyzed theoretically. It is shown that dispersion compensation is best implemented by use of reference measurements around absolute zero in the interferometer. Furthermore, the effects of wavelength uncertainty allow the ultimate performance of an MWI interferometer to be estimated.

Large Magellanic Cloud Distance and Structure from Near-Infrared Red Clump Observations

NASA Astrophysics Data System (ADS)

Koerwer, Joel F.

2009-07-01

We have applied the Infrared Survey Facility Magellanic Clouds Point-Source Catalog to the mapping of the red clump (RC) distance modulus across the Large Magellanic Cloud (LMC). Using the J- (1.25 μm) and H- (1.63 μm) band data to derive a reddening free luminosity function and a theoretical RC absolute magnitude from stellar evolution libraries, we estimate a distance modulus to the LMC of μ = 18.54 ± 0.06. The best fitting plane inclination, i, and the position angle of the line of nodes, phi, have little dependence on the assumed RC absolute magnitude; we find i = 23fdg5 ± 0fdg4 and phi = 154fdg6 ± 1fdg2. It was also noted that many fields included a significant asymptotic giant branch bump population that must be accounted for.

Absolute frequency list of the ν3-band transitions of methane at a relative uncertainty level of 10(-11).

PubMed

Okubo, Sho; Nakayama, Hirotaka; Iwakuni, Kana; Inaba, Hajime; Sasada, Hiroyuki

2011-11-21

We determine the absolute frequencies of 56 rotation-vibration transitions of the ν(3) band of CH(4) from 88.2 to 90.5 THz with a typical uncertainty of 2 kHz corresponding to a relative uncertainty of 2.2 × 10(-11) over an average time of a few hundred seconds. Saturated absorption lines are observed using a difference-frequency-generation source and a cavity-enhanced absorption cell, and the transition frequencies are measured with a fiber-laser-based optical frequency comb referenced to a rubidium atomic clock linked to the international atomic time. The determined value of the P(7) F(2)((2)) line is consistent with the International Committee for Weights and Measures recommendation within the uncertainty. © 2011 Optical Society of America

Initial Characterization of Unequal-Length, Low-Background Proportional Counters for Absolute Gas-Counting Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mace, Emily K.; Aalseth, Craig E.; Bonicalzi, Ricco

Abstract. Characterization of two sets of custom unequal length proportional counters is underway at Pacific Northwest National Laboratory (PNNL). These detectors will be used in measurements to determine the absolute activity concentration of gaseous radionuclides (e.g., 37Ar). A set of three detectors has been fabricated based on previous PNNL ultra-low-background proportional counters (ULBPC) designs and now operate in PNNL’s shallow underground counting laboratory. A second set of four counters has also been fabricated using clean assembly of OFHC copper components for use in an above-ground counting laboratory. Characterization of both sets of detectors is underway with measurements of background rates,more » gas gain, energy resolution, and shielding considerations. These results will be presented along with uncertainty estimates of future absolute gas counting measurements.« less

Weak acid extractable metals in Bramble Bay, Queensland, Australia: temporal behaviour, enrichment and source apportionment.

PubMed

Brady, James P; Ayoko, Godwin A; Martens, Wayde N; Goonetilleke, Ashantha

2015-02-15

Sediment samples were taken from six sampling sites in Bramble Bay, Queensland, Australia between February and November in 2012. They were analysed for a range of heavy metals including Al, Fe, Mn, Ti, Ce, Th, U, V, Cr, Co, Ni, Cu, Zn, As, Cd, Sb, Te, Hg, Tl and Pb. Fraction analysis, Enrichment Factors and Principal Component Analysis-Absolute Principal Component Scores (PCA-APCS) were carried out in order to assess metal pollution, potential bioavailability and source apportionment. Cr and Ni exceeded the Australian Interim Sediment Quality Guidelines at some sampling sites, while Hg was found to be the most enriched metal. Fraction analysis identified increased weak acid soluble Hg and Cd during the sampling period. Source apportionment via PCA-APCS found four sources of metals pollution, namely, marine sediments, shipping, antifouling coatings and a mixed source. These sources need to be considered in any metal pollution control measure within Bramble Bay. Copyright © 2014 Elsevier Ltd. All rights reserved.

Atmospheric polycyclic aromatic hydrocarbons in the urban environment: Occurrence, toxicity and source apportionment.

PubMed

Mishra, Nitika; Ayoko, Godwin A; Morawska, Lidia

2016-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) represent a major class of toxic pollutants because of their carcinogenic and mutagenic characteristics. People living in urban areas are regularly exposed to PAHs because of abundance of their emission sources. Within this context, this study aimed to: (i) identify and quantify the levels of ambient PAHs in an urban environment; (ii) evaluate their toxicity; and (iii) identify their sources as well as the contribution of specific sources to measured concentrations. Sixteen PAHs were identified and quantified in air samples collected from Brisbane. Principal Component Analysis - Absolute Principal Component Scores (PCA-APCS) was used in order to conduct source apportionment of the measured PAHs. Vehicular emissions, natural gas combustion, petrol emissions and evaporative/unburned fuel were the sources identified; contributing 56%, 21%, 15% and 8% of the total PAHs emissions, respectively, all of which need to be considered for any pollution control measures implemented in urban areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

76 FR 25240 - Clothianidin; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-04

... neurotoxicity were exhibited in both rats (decreased arousal, motor activity and locomotor activity) and mice... (decreased body weight gains and absolute thymus weights in pups, delayed sexual maturation and an increase.../day FQPA SF = 1x day.. based on decreased body weight gains and delayed sexual maturation, decreased...

Active Travel to Primary Schools in Ireland: An Opportunistic Evaluation of a Natural Experiment.

PubMed

Lambe, Barry; Murphy, Niamh; Bauman, Adrian

2017-06-01

There is a paucity of intervention studies assessing active travel to school as a mechanism to increase physical activity. This paper describes the impact of a community-wide intervention on active travel to primary schools in 2 Irish towns. This was a repeat cross-sectional study of a natural experiment. Self-report questionnaires were completed by 5th and 6th grade students in 3 towns (n = 1038 students in 2 intervention towns; n = 419 students in 1 control town) at baseline and by a new group of students 2 years later at follow-up. The absolute change in the proportion of children walking and cycling to school (difference in differences) was calculated. There was no overall intervention effect detected for active travel to or from school. This is despite an absolute increase of 14.7% (1.6, 27.9) in the proportion of children that indicated a preference for active travel to school in the town with the most intensive intervention (town 2). Interventions designed to increase active travel to school hold some promise but should have a high-intensity mix of infrastructural and behavioral measures, be gender-specific, address car dependency and focus on travel home from school initially.

In vivo antiulcer activity of the aqueous extract of Bauhinia purpurea leaf.

PubMed

Zakaria, Z A; Abdul Hisam, E E; Rofiee, M S; Norhafizah, M; Somchit, M N; Teh, L K; Salleh, M Z

2011-09-02

Bauhinia purpurea (Fabaceae) is a medicinal plant traditionally used to treat various ailments, including ulcers. In order to establish pharmacological properties of the leaf of Bauhinia purpurea, studies were performed on antiulcer activity of the plant's aqueous extract. The Bauhinia purpurea aqueous extract (BPAE) was prepared in the doses of 100, 500 and 1,000 mg/kg. Antiulcer activity of BPAE was evaluated by absolute ethanol- and indomethacin-induced gastric ulcer, and pyloric ligation models. Acute toxicity was also carried out. BPAE, at the dose of 5,000 mg/kg, did not cause any signs of toxicity to rats when given orally. Oral administration of BPAE exhibited antiulcer activity (p<0.05) in all models used. However, the dose-dependent activity was observed only in the absolute ethanol-induced gastric ulcer model. Histological studies supported the observed antiulcer activity of BPAE. In pyloric ligation assay, BPAE increased the gastric wall mucus secretion. The BPAE exhibits antiulcer activity, which could be due to the presence of saponins or sugar-free polyphenols, and, thus, confirmed the traditional uses of Bauhinia purpurea in the treatment of ulcers. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Preliminary Investigation of Longitudinal Differences in TEC and Scintillation at Transition Latitudes

DTIC Science & Technology

1991-04-04

AIR. j NO ABSOLUTE TEC. C: NEW SATELITE WINDOWS INSERTED. j - IAPEDRIVE PROBLEM. D: SOME DATA ON CHART NOT RECORDED ON TAPE. H = NPIB INTERFASE...PROBLEM. E: SOME DATA BROKEN UP. V 2 FLOPPY DISK/DRIVE PROBLEM. F: TAPE CHANGE. W - WRONG SATELITE WINDOWS. TOTAL HOURS OF ACTIVITY LEVEL 1:300 P - POWER...0 1 0 31 1 COMMENT’S: ADDITIONAL COMMENT’S. A: TAPE STOP * L1/L2 SCINTILLATION. B: GPS SYSTEM OFF THE AIR. O= N ABSOLUTE TEC. C: NEW SATELITE WINDOWS

Demand forecasting of electricity in Indonesia with limited historical data

NASA Astrophysics Data System (ADS)

Dwi Kartikasari, Mujiati; Rohmad Prayogi, Arif

2018-03-01

Demand forecasting of electricity is an important activity for electrical agents to know the description of electricity demand in future. Prediction of demand electricity can be done using time series models. In this paper, double moving average model, Holt’s exponential smoothing model, and grey model GM(1,1) are used to predict electricity demand in Indonesia under the condition of limited historical data. The result shows that grey model GM(1,1) has the smallest value of MAE (mean absolute error), MSE (mean squared error), and MAPE (mean absolute percentage error).

Concise synthesis and PTP1B inhibitory activity of (R)- and (S)-dihydroresorcylide.

PubMed

Jiang, Cheng-Shi; Zhang, Li; Gong, Jing-Xu; Li, Jing-Ya; Yao, Li-Gong; Li, Jia; Guo, Yue-Wei

2017-12-01

The present study was designed to develop a concise synthetic route for macrolide, with the purpose of confirming the absolute configuration of natural dihydroresorcylide (1) and making it more easily accessible for biological evaluation. The absolute configuration of C-3 in natural 1 was revised to be R by comparison of the rotation sign of synthetic (R)- and (S)-1. The synthetic (R)-1 was found to be a novel highly specific PTP1B inhibitor with an IC 50 value of 17.06 μM.

Exponential bound in the quest for absolute zero

NASA Astrophysics Data System (ADS)

Stefanatos, Dionisis

2017-10-01

In most studies for the quantification of the third law of thermodynamics, the minimum temperature which can be achieved with a long but finite-time process scales as a negative power of the process duration. In this article, we use our recent complete solution for the optimal control problem of the quantum parametric oscillator to show that the minimum temperature which can be obtained in this system scales exponentially with the available time. The present work is expected to motivate further research in the active quest for absolute zero.

Exponential bound in the quest for absolute zero.

PubMed

Stefanatos, Dionisis

2017-10-01

In most studies for the quantification of the third law of thermodynamics, the minimum temperature which can be achieved with a long but finite-time process scales as a negative power of the process duration. In this article, we use our recent complete solution for the optimal control problem of the quantum parametric oscillator to show that the minimum temperature which can be obtained in this system scales exponentially with the available time. The present work is expected to motivate further research in the active quest for absolute zero.

(abstract) Absolute Flux Calibrations of Venus and Jupiter at 32 GHz

NASA Technical Reports Server (NTRS)

Gatti, Mark S.; Klein, Michael J.

1994-01-01

The microwave flux densities of Venus and Jupiter at 32 GHz have been measured using a calibration standard radio telescope system at the Owens Valley Radio Observatory (OVRO) during April and May of 1993. These measurements are part of a joint JPL/Caltech program to accurately calibrate a catalog of other radio sources using the two bright planets as flux standards.

JPRS Report, Proliferation Issues

DTIC Science & Technology

1993-03-22

delivering abroad polonium sources (with experimental physics. polonium - 210 radioisotopes) for several decades now. They are mostly used in space...the principle of unanimity, SK1303012993 Seoul YONHAP in English 0118 GMT the Japanese position effectively killed the resolution. 13 Mar 93 The APPU...and soul of effective , this would be a great mistake, our people, and disarm us," Kang said. We absolutely cannot assume the responsibility, even "The

Empirical Green's function analysis: Taking the next step

USGS Publications Warehouse

Hough, S.E.

1997-01-01

An extension of the empirical Green's function (EGF) method is presented that involves determination of source parameters using standard EGF deconvolution, followed by inversion for a common attenuation parameter for a set of colocated events. Recordings of three or more colocated events can thus be used to constrain a single path attenuation estimate. I apply this method to recordings from the 1995-1996 Ridgecrest, California, earthquake sequence; I analyze four clusters consisting of 13 total events with magnitudes between 2.6 and 4.9. I first obtain corner frequencies, which are used to infer Brune stress drop estimates. I obtain stress drop values of 0.3-53 MPa (with all but one between 0.3 and 11 MPa), with no resolved increase of stress drop with moment. With the corner frequencies constrained, the inferred attenuation parameters are very consistent; they imply an average shear wave quality factor of approximately 20-25 for alluvial sediments within the Indian Wells Valley. Although the resultant spectral fitting (using corner frequency and ??) is good, the residuals are consistent among the clusters analyzed. Their spectral shape is similar to the the theoretical one-dimensional response of a layered low-velocity structure in the valley (an absolute site response cannot be determined by this method, because of an ambiguity between absolute response and source spectral amplitudes). I show that even this subtle site response can significantly bias estimates of corner frequency and ??, if it is ignored in an inversion for only source and path effects. The multiple-EGF method presented in this paper is analogous to a joint inversion for source, path, and site effects; the use of colocated sets of earthquakes appears to offer significant advantages in improving resolution of all three estimates, especially if data are from a single site or sites with similar site response.

Design and characterization of a new high-dose-rate brachytherapy Valencia applicator for larger skin lesions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Candela-Juan, C., E-mail: ccanjuan@gmail.com; Niatsetski, Y.; Laarse, R. van der

Purpose: The aims of this study were (i) to design a new high-dose-rate (HDR) brachytherapy applicator for treating surface lesions with planning target volumes larger than 3 cm in diameter and up to 5 cm in size, using the microSelectron-HDR or Flexitron afterloader (Elekta Brachytherapy) with a {sup 192}Ir source; (ii) to calculate by means of the Monte Carlo (MC) method the dose distribution for the new applicator when it is placed against a water phantom; and (iii) to validate experimentally the dose distributions in water. Methods: The PENELOPE2008 MC code was used to optimize dwell positions and dwell times.more » Next, the dose distribution in a water phantom and the leakage dose distribution around the applicator were calculated. Finally, MC data were validated experimentally for a {sup 192}Ir mHDR-v2 source by measuring (i) dose distributions with radiochromic EBT3 films (ISP); (ii) percentage depth–dose (PDD) curve with the parallel-plate ionization chamber Advanced Markus (PTW); and (iii) absolute dose rate with EBT3 films and the PinPoint T31016 (PTW) ionization chamber. Results: The new applicator is made of tungsten alloy (Densimet) and consists of a set of interchangeable collimators. Three catheters are used to allocate the source at prefixed dwell positions with preset weights to produce a homogenous dose distribution at the typical prescription depth of 3 mm in water. The same plan is used for all available collimators. PDD, absolute dose rate per unit of air kerma strength, and off-axis profiles in a cylindrical water phantom are reported. These data can be used for treatment planning. Leakage around the applicator was also scored. The dose distributions, PDD, and absolute dose rate calculated agree within experimental uncertainties with the doses measured: differences of MC data with chamber measurements are up to 0.8% and with radiochromic films are up to 3.5%. Conclusions: The new applicator and the dosimetric data provided here will be a valuable tool in clinical practice, making treatment of large skin lesions simpler, faster, and safer. Also the dose to surrounding healthy tissues is minimal.« less

Biomass burning source characterization requirements in air quality models with and without data assimilation: challenges and opportunities

NASA Astrophysics Data System (ADS)

Hyer, E. J.; Zhang, J. L.; Reid, J. S.; Curtis, C. A.; Westphal, D. L.

2007-12-01

Quantitative models of the transport and evolution of atmospheric pollution have graduated from the laboratory to become a part of the operational activity of forecast centers. Scientists studying the composition and variability of the atmosphere put great efforts into developing methods for accurately specifying sources of pollution, including natural and anthropogenic biomass burning. These methods must be adapted for use in operational contexts, which impose additional strictures on input data and methods. First, only input data sources available in near real-time are suitable for use in operational applications. Second, operational applications must make use of redundant data sources whenever possible. This is a shift in philosophy: in a research context, the most accurate and complete data set will be used, whereas in an operational context, the system must be designed with maximum redundancy. The goal in an operational context is to produce, to the extent possible, consistent and timely output, given sometimes inconsistent inputs. The Naval Aerosol Analysis and Prediction System (NAAPS), a global operational aerosol analysis and forecast system, recently began incorporating assimilation of satellite-derived aerosol optical depth. Assimilation of satellite AOD retrievals has dramatically improved aerosol analyses and forecasts from this system. The use of aerosol data assimilation also changes the strategy for improving the smoke source function. The absolute magnitude of emissions events can be refined through feedback from the data assimilation system, both in real- time operations and in post-processing analysis of data assimilation results. In terms of the aerosol source functions, the largest gains in model performance are now to be gained by reducing data latency and minimizing missed detections. In this presentation, recent model development work on the Fire Locating and Monitoring of Burning Emissions (FLAMBE) system that provides smoke aerosol boundary conditions for NAAPS is described, including redundant integration of multiple satellite platforms and development of feedback loops between the data assimilation system and smoke source.

Biomass burning in the Amazon region: Aerosol source apportionment and associated health risk assessment

NASA Astrophysics Data System (ADS)

de Oliveira Alves, Nilmara; Brito, Joel; Caumo, Sofia; Arana, Andrea; de Souza Hacon, Sandra; Artaxo, Paulo; Hillamo, Risto; Teinilä, Kimmo; Batistuzzo de Medeiros, Silvia Regina; de Castro Vasconcellos, Pérola

2015-11-01

The Brazilian Amazon represents about 40% of the world's remaining tropical rainforest. However, human activities have become important drivers of disturbance in that region. The majority of forest fire hotspots in the Amazon arc due to deforestation are impacting the health of the local population of over 10 million inhabitants. In this study we characterize western Amazonia biomass burning emissions through the quantification of 14 Polycyclic Aromatic Hydrocarbons (PAHs), Organic Carbon, Elemental Carbon and unique tracers of biomass burning such as levoglucosan. From the PAHs dataset a toxic equivalence factor is calculated estimating the carcinogenic and mutagenic potential of biomass burning emissions during the studied period. Peak concentration of PM10 during the dry seasons was observed to reach 60 μg m-3 on the 24 h average. Conversely, PM10 was relatively constant throughout the wet season indicating an overall stable balance between aerosol sources and sinks within the filter sampling resolution. Similar behavior is identified for OC and EC components. Levoglucosan was found in significant concentrations (up to 4 μg m-3) during the dry season. Correspondingly, the estimated lung cancer risk calculated during the dry seasons largely exceeded the WHO health-based guideline. A source apportionment study was carried out through the use of Absolute Principal Factor Analysis (APFA), identifying a three-factor solution. The biomass burning factor is found to be the dominating aerosol source, having 75.4% of PM10 loading. The second factor depicts an important contribution of several PAHs without a single source class and therefore was considered as mixed sources factor, contributing to 6.3% of PM10. The third factor was mainly associated with fossil fuel combustion emissions, contributing to 18.4% of PM10. This work enhances the knowledge of aerosol sources and its impact on climate variability and local population, on a site representative of the deforestation which occupies a significant fraction of the Amazon basin.

Temporal Variations in 234U/238U Activity Ratios in Four Mississippi River Tributaries

NASA Astrophysics Data System (ADS)

Grzymko, T. J.; Marcantonio, F.

2005-05-01

In 2004 we sampled the four tributaries that are the major contributors to the Mississippi River in terms of water discharge, i.e., the Arkansas, Missouri, Upper Mississippi, and Ohio rivers. Each river was sampled four times over the course of the year at variable levels of discharge in an attempt to constrain the causes of the temporal variations of 234U/238U activity ratios in the lower Mississippi River at New Orleans. The tributary uranium data support the idea that lower river uranium isotope and elemental systematics are controlled by a simple mass balance of the source tributary discharges. Furthermore, the uranium isotope ratios of the individual tributaries show coherent patterns of variability. Specifically, the data obtained from the four sampling trips yielded similar patterns of temporal variation in the 234U/238U activity ratios of all of the rivers, although the absolute values of these ratios were distinctly different from one river to the next. The pattern was such that the highest 234U/238U activity ratios were observed during the highest flow associated with the spring freshet while the lowest ratios occurred during the summer. For example, in the Missouri River, the 234U/238U activity ratios varied from 1.51 (February 12) to 1.37 (April 14) to 1.34 (July 16) to 1.37 (November 12), while in the Ohio River the same ratios varied from 1.36 (February 12) to 1.29 (April 14) to 1.21 (July 16) to 1.23 (November 12). The apparent seasonal pattern of these ratios in each tributary has led to several ideas as to the causes of the observed trends. The first, and most obvious, is that in each individual drainage basin there are various source tributaries that contribute to the uranium isotope systematics of the main stem of the tributary of interest. It follows that the variations in the uranium activity ratios may be caused by spatial variations in the source rock chemistry of the drainage basin. Other more complex scenarios can also be envisioned and will be discussed. For example, we explore the possibility that the highest ratios associated with the spring freshet are a consequence of snow melt and the flushing of 234U from fresh surfaces created via physical weathering associated with the winter freeze-thaw cycles.

Influence of Co-57 and CT Transmission Measurements on the Quantification Accuracy and Partial Volume Effect of a Small Animal PET Scanner.

PubMed

Mannheim, Julia G; Schmid, Andreas M; Pichler, Bernd J

2017-12-01

Non-invasive in vivo positron emission tomography (PET) provides high detection sensitivity in the nano- to picomolar range and in addition to other advantages, the possibility to absolutely quantify the acquired data. The present study focuses on the comparison of transmission data acquired with an X-ray computed tomography (CT) scanner or a Co-57 source for the Inveon small animal PET scanner (Siemens Healthcare, Knoxville, TN, USA), as well as determines their influences on the quantification accuracy and partial volume effect (PVE). A special focus included the impact of the performed calibration on the quantification accuracy. Phantom measurements were carried out to determine the quantification accuracy, the influence of the object size on the quantification, and the PVE for different sphere sizes, along the field of view and for different contrast ratios. An influence of the emission activity on the Co-57 transmission measurements was discovered (deviations up to 24.06 % measured to true activity), whereas no influence of the emission activity on the CT attenuation correction was identified (deviations <3 % for measured to true activity). The quantification accuracy was substantially influenced by the applied calibration factor and by the object size. The PVE demonstrated a dependency on the sphere size, the position within the field of view, the reconstruction and correction algorithms and the count statistics. Depending on the reconstruction algorithm, only ∼30-40 % of the true activity within a small sphere could be resolved. The iterative 3D reconstruction algorithms uncovered substantially increased recovery values compared to the analytical and 2D iterative reconstruction algorithms (up to 70.46 % and 80.82 % recovery for the smallest and largest sphere using iterative 3D reconstruction algorithms). The transmission measurement (CT or Co-57 source) to correct for attenuation did not severely influence the PVE. The analysis of the quantification accuracy and the PVE revealed an influence of the object size, the reconstruction algorithm and the applied corrections. Particularly, the influence of the emission activity during the transmission measurement performed with a Co-57 source must be considered. To receive comparable results, also among different scanner configurations, standardization of the acquisition (imaging parameters, as well as applied reconstruction and correction protocols) is necessary.

Three-dimensional localization of abnormal EEG activity in migraine: a low resolution electromagnetic tomography (LORETA) study of migraine patients in the pain-free interval.

PubMed

Clemens, Béla; Bánk, József; Piros, Pálma; Bessenyei, Mónika; Veto, Sára; Tóth, Márton; Kondákor, István

2008-09-01

Investigating the brain of migraine patients in the pain-free interval may shed light on the basic cerebral abnormality of migraine, in other words, the liability of the brain to generate migraine attacks from time to time. Twenty unmedicated "migraine without aura" patients and a matched group of healthy controls were investigated in this explorative study. 19-channel EEG was recorded against the linked ears reference and was on-line digitized. 60 x 2-s epochs of eyes-closed, waking-relaxed activity were subjected to spectral analysis and a source localization method, low resolution electromagnetic tomography (LORETA). Absolute power was computed for 19 electrodes and four frequency bands (delta: 1.5-3.5 Hz, theta: 4.0-7.5 Hz, alpha: 8.0-12.5 Hz, beta: 13.0-25.0 Hz). LORETA "activity" (=current source density, ampers/meters squared) was computed for 2394 voxels and the above specified frequency bands. Group comparison was carried out for the specified quantitative EEG variables. Activity in the two groups was compared on a voxel-by-voxel basis for each frequency band. Statistically significant (uncorrected P < 0.01) group differences were projected to cortical anatomy. Spectral findings: there was a tendency for more alpha power in the migraine that in the control group in all but two (F4, C3) derivations. However, statistically significant (P < 0.01, Bonferroni-corrected) spectral difference was only found in the right occipital region. The main LORETA-finding was that voxels with P < 0.01 differences were crowded in anatomically contiguous cortical areas. Increased alpha activity was found in a cortical area including part of the precuneus, and the posterior part of the middle temporal gyrus in the right hemisphere. Decreased alpha activity was found bilaterally in medial parts of the frontal cortex including the anterior cingulate and the superior and medial frontal gyri. Neither spectral analysis, nor LORETA revealed statistically significant differences in the delta, theta, and beta bands. LORETA revealed the anatomical distribution of the cortical sources (generators) of the EEG abnormalities in migraine. The findings characterize the state of the cerebral cortex in the pain-free interval and might be suitable for planning forthcoming investigations.

Absolute configuration of podophyllotoxone and its inhibitory activity against human prostate cancer cells.

PubMed

Li, Juan; Feng, Juan; Luo, Cheng; Herman, Ho-Yung Sung; Jiang, Ren-Wang

2015-01-01

Podophyllotoxone (1) was isolated from the roots of Dysosma versipellis. The structure was determined by spectroscopic analysis in combination with single-crystal X-ray analysis. The absolute configuration of compound 1 was assigned based on the Flack parameter. It showed significant inhibitory activities against human prostate cancer cells PC3 and DU145 with IC50 values being 14.7 and 20.6 μmol·L(-1), respectively. It also arrested the cells at G2/M phase. Tubulin polymerization assay showed that it inhibited the tubulin polymerization in a dose-dependent manner, and molecular docking analysis revealed a different binding mode with tubulin as compared with those known tubulin inhibitors. Copyright © 2015 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Experimental and theoretical calculation studies on the structure elucidation and absolute configuration of calyxins from Alpinia katsumadai.

PubMed

Wang, Xiao-Bing; Yang, Chang-Shui; Luo, Jian-Guang; Zhang, Chao; Luo, Jun; Yang, Ming-Hua; Kong, Ling-Yi

2017-06-01

Six novel calyxins, named calyxin T-W, ent-calyxin T and ent-calyxin U were isolated from the seeds of Alpinia katsumadai Hayata. Their relative configurations were elucidated by means of detailed UV, IR, NMR and MS spectroscopic data. Their absolute configurations were assigned by collaborative studies on single crystal X-ray diffraction analysis, Mosher's method, electronic circular dichroism (ECD), optical rotation and theoretical calculations. These compounds are Friedel-Cranft alkylation adducts composed of coexisted diarylheptanoids and flavanone from the seeds of Alpinia katsumadai. The antiproliferative activity of the six compounds against NCI-H460, HeLa, SMMC-7721 and HCT-116 cell lines was also reported, and most of them showed moderate to strong activities. Copyright © 2017. Published by Elsevier B.V.

Volcanic Surface Deformation in Dominica From GPS Geodesy: Results From the 2007 NSF- REU Site

NASA Astrophysics Data System (ADS)

Murphy, R.; James, S.; Styron, R. H.; Turner, H. L.; Ashlock, A.; Cavness, C.; Collier, X.; Fauria, K.; Feinstein, R.; Staisch, L.; Williams, B.; Mattioli, G. S.; Jansma, P. E.; Cothren, J.

2007-12-01

GPS measurements have been collected on the island of Dominica in the Lesser Antilles between 2001 and 2007, with five month-long campaigns completed in June of each year supported in part by a NSF REU Site award for the past two years. All GPS data were collected using dual-frequency, code-phase receivers and geodetic-quality antenna, primarily choke rings. Three consecutive 24 hr observation days were normally obtained for each site. Precise station positions were estimated with GIPSY-OASISII using an absolute point positioning strategy and final, precise orbits, clocks, earth orientation parameters, and x-files. All position estimates were updated to ITRF05 and a revised Caribbean Euler pole was used to place our observations in a CAR-fixed frame. Time series were created to determine the velocity of each station. Forward and inverse elastic half-space models with planar (i.e. dike) and Mogi (i.e. point) sources were investigated. Inverse modeling was completed using a downhill simplex method of function minimization. Selected site velocities were used to create appropriate models for specific regions of Dominica, which correspond to known centers of pre-historic volcanic or recent shallow, seismic activity. Because of the current distribution of GPS sites with robust velocity estimates, we limit our models to possible magmatic activity in the northern, proximal to the volcanic centers of Morne Diablotins and Morne aux Diables, and southern, proximal to volcanic centers of Soufriere and Morne Plat Pays, regions of the island. Surface deformation data from the northernmost sites may be fit with the development of a several km-long dike trending approximately northeast- southwest. Activity in the southern volcanic centers is best modeled by an expanding point source at approximately 1 km depth.

Immunological parameters in elderly women: correlations with aerobic power, muscle strength and mood state.

PubMed

Raso, Vagner; Natale, Valéria Maria; Duarte, Alberto José da Silva; Greve, Júlia Maria D'Andrea; Shephard, Roy J

2012-05-01

Our objective was to relate immunological data for healthy but sedentary elderly women to aerobic power, strength, and mood state. We measured peak aerobic power and one-repetition maximum strength along with mood (depression and fatigue), quality of life and carbohydrate intake on 42 women aged 60-77 years. Standard immunological techniques determined natural killer cell count and cytotoxic activity (NKCA), proliferative responses to phytohemaglutinin and OKT(3), various lymphocyte subpopulations (CD3(+), CD3(-)CD19(+), CD56(+), CD4(+), CD8(+), CD56(dim) and CD56(bright)), and markers of activation, maturation, down-regulation and susceptibility to apoptosis (CD25(+), CD28(+), CD45RA(+), CD45RO(+), CD69(+), CD95(+), HLA-DR(+)). Correlations of immune parameters with aerobic power and strength were very similar for absolute and relative immunological data. In the group as a whole, the only correlation with aerobic power was -0.35 (relative CD4(+)CD69(+) count), but in subjects with values <22.6 mL kg(-1)min(-1) correlations ranged from -0.57 (relative CD4(+)CD45RO(+)) to 0.92 (absolute CD56(dim)HLA-DR(+)). In terms of muscle strength, univariate correlation coefficients ranged from -0.34 (relative and absolute CD3(+)CD4(+)CD8(+)) to +0.48 (absolute CD3(+)HLA-DR(+)) and +0.50 (absolute CD8(+)CD45RA(+)CD45RO(+)). Neither NKCA nor lymphocyte proliferation were correlated with aerobic power or muscle strength. Although mood state and quality of life can sometimes be influenced by an individual's fitness level, our multivariate analyses suggested that depression, fatigue and quality of life were more important determinants of immune profile than our fitness measures. Psychological changes associated with aging may have a substantial adverse effect upon the immune system, and immunological function may be enhanced more by addressing these issues than by focusing upon aerobic or resistance training. Copyright © 2012 Elsevier Inc. All rights reserved.

Two new pyrrolo-2-aminoimidazoles from a Myanmarese marine sponge, Clathria prolifera.

PubMed

Woo, So-Yeun; Win, Nwet Nwet; Wong, Chin Piow; Ito, Takuya; Hoshino, Shotaro; Ngwe, Hla; Aye, Aung Aung; Han, Nang Mya; Zhang, Huiping; Hayashi, Fumiaki; Abe, Ikuro; Morita, Hiroyuki

2018-06-01

Marine organisms such as marine sponges and soft corals are valuable sources of pharmacologically active secondary metabolites. In our ongoing research on the discovery of new secondary metabolites from marine organisms, two new pyrrolo-2-aminoimidazoles, clathriroles A (1) and B (2), were isolated from the water-soluble portion prepared from the methanol and acetone (2:1) extract of the marine sponge, Clathria prolifera, collected in Myanmar. The chemical structures of the isolated compounds were determined using extensive spectroscopic techniques, including NMR, HRESIMS, IR, and optical rotation, and comparisons with the reported literature. The spectroscopic analyses of 1 and 2 suggested that 1 is an enantiomer of antifungal N-methylmanzacidin C isolated from the marine sponge Axinella brevistyla, whereas 2 is a diastereomer of manzacidin D at C-11 isolated from the marine sponge Astrosclera willeyana. To the best of our knowledge, this is the first report of the isolation of the pyrrolo-2-aminoimidazole compounds from C. prolifera. Furthermore, in contrast to the potency of N-methylmanzacidin C against Saccharomyces cerevisiae, the antifungal assay revealed that 1 and 2 lack any activity against this strain. Thus, these observations may suggest that the absolute configurations at both C-9 and C-11 play an important role in controlling the antifungal activity of this type of compound.

Evaluation of von Willebrand factor in COPD patients*

PubMed Central

Bártholo, Thiago Prudente; da Costa, Cláudia Henrique; Rufino, Rogério

2014-01-01

OBJECTIVE: To compare the absolute serum von Willebrand factor (vWF) levels and relative serum vWF activity in patients with clinically stable COPD, smokers without airway obstruction, and healthy never-smokers. METHODS: The study included 57 subjects, in three groups: COPD (n = 36); smoker (n = 12); and control (n = 9). During the selection phase, all participants underwent chest X-rays, spirometry, and blood testing. Absolute serum vWF levels and relative serum vWF activity were obtained by turbidimetry and ELISA, respectively. The modified Medical Research Council scale (cut-off score = 2) was used in order to classify COPD patients as symptomatic or mildly symptomatic/asymptomatic. RESULTS: Absolute vWF levels were significantly lower in the control group than in the smoker and COPD groups: 989 ± 436 pg/mL vs. 2,220 ± 746 pg/mL (p < 0.001) and 1,865 ± 592 pg/mL (p < 0.01). Relative serum vWF activity was significantly higher in the COPD group than in the smoker group (136.7 ± 46.0% vs. 92.8 ± 34.0%; p < 0.05), as well as being significantly higher in the symptomatic COPD subgroup than in the mildly symptomatic/asymptomatic COPD subgroup (154 ± 48% vs. 119 ± 8%; p < 0.05). In all three groups, there was a negative correlation between FEV1 (% of predicted) and relative serum vWF activity (r2 = −0.13; p = 0.009). CONCLUSIONS: Our results suggest that increases in vWF levels and activity contribute to the persistence of systemic inflammation, as well as increasing cardiovascular risk, in COPD patients. PMID:25210959

Validation of the "German Inflammatory Bowel Disease Activity Index (GIBDI)": An Instrument for Patient-Based Disease Activity Assessment in Crohn's Disease and Ulcerative Colitis.

PubMed

Hüppe, Angelika; Langbrandtner, Jana; Häuser, Winfried; Raspe, Heiner; Bokemeyer, Bernd

2018-05-09

 Assessment of disease activity in Crohn's disease (CD) and ulcerative colitis (UC) is usually based on the physician's evaluation of clinical symptoms, endoscopic findings, and biomarker analysis. The German Inflammatory Bowel Disease Activity Index for CD (GIBDI CD ) and UC (GIBDI UC ) uses data from patient-reported questionnaires. It is unclear to what extent the GIBDI agrees with the physicians' documented activity indices.  Data from 2 studies were reanalyzed. In both, gastroenterologists had documented disease activity in UC with the partial Mayo Score (pMS) and in CD with the Harvey Bradshaw Index (HBI). Patient-completed GIBDI questionnaires had also been assessed. The analysis sample consisted of 151 UC and 150 CD patients. Kappa coefficients were determined as agreement measurements.  Rank correlations were 0.56 (pMS, GIBDI UC ) and 0.57 (HBI, GIBDI CD ), with p < 0.001. The absolute agreement for 2 categories of disease activity (remission yes/no) was 74.2 % (UC) and 76.6 % (CD), and for 4 categories (none/mild/moderate/severe) 60.3 % (UC) and 61.9 % (CD). The kappa values ranged between 0.47 for UC (2 categories) and 0.58 for CD (4 categories).  There is satisfactory agreement of GIBDI with the physician-documented disease activity indices. GIBDI can be used in health care research without access to assessments of medical practitioners. In clinical practice, the index offers a supplementary source of information. © Georg Thieme Verlag KG Stuttgart · New York.

Characterization of earthquake-induced ground motion from the L'Aquila seismic sequence of 2009, Italy

NASA Astrophysics Data System (ADS)

Malagnini, Luca; Akinci, Aybige; Mayeda, Kevin; Munafo', Irene; Herrmann, Robert B.; Mercuri, Alessia

2011-01-01

Based only on weak-motion data, we carried out a combined study on region-specific source scaling and crustal attenuation in the Central Apennines (Italy). Our goal was to obtain a reappraisal of the existing predictive relationships for the ground motion, and to test them against the strong-motion data [peak ground acceleration (PGA), peak ground velocity (PGV) and spectral acceleration (SA)] gathered during the Mw 6.15 L'Aquila earthquake (2009 April 6, 01:32 UTC). The L'Aquila main shock was not part of the predictive study, and the validation test was an extrapolation to one magnitude unit above the largest earthquake of the calibration data set. The regional attenuation was determined through a set of regressions on a data set of 12 777 high-quality, high-gain waveforms with excellent S/N ratios (4259 vertical and 8518 horizontal time histories). Seismograms were selected from the recordings of 170 foreshocks and aftershocks of the sequence (the complete set of all earthquakes with ML≥ 3.0, from 2008 October 1 to 2010 May 10). All waveforms were downloaded from the ISIDe web page (), a web site maintained by the Istituto Nazionale di Geofisica e Vulcanologia (INGV). Weak-motion data were used to obtain a moment tensor solution, as well as a coda-based moment-rate source spectrum, for each one of the 170 events of the L'Aquila sequence (2.8 ≤Mw≤ 6.15). Source spectra were used to verify the good agreement with the source scaling of the Colfiorito seismic sequence of 1997-1998 recently described by Malagnini (2008). Finally, results on source excitation and crustal attenuation were used to produce the absolute site terms for the 23 stations located within ˜80 km of the epicentral area. The complete set of spectral corrections (crustal attenuation and absolute site effects) was used to implement a fast and accurate tool for the automatic computation of moment magnitudes in the Central Apennines.

Consequences count: against absolutism at the end of life.

PubMed

Snelling, Paul C

2004-05-01

There has been a considerable amount of debate in the nursing literature about euthanasia, and especially the distinctions between acts and omissions, and killing and letting die. These distinctions are required by opponents of euthanasia to justify allowing some cases of passive euthanasia while forbidding all cases of active euthanasia. This paper adds to the debate by arguing that the position that absolutely forbids euthanasia is theoretically inconsistent. The paper first considers the place of moral theory in analysing moral problems, within the framework of the principles of biomedical ethics. It is argued that despite a moral pluralism that operates in many areas, the legal status of euthanasia is based upon an absolute deontological position against deliberate killing, which cannot be overridden by appeals to favourable consequences. In order that certain forms of passive euthanasia can be allowed, this position allows distinctions within three pairs of concepts--acts and omissions, killing and letting die, and ordinary and extraordinary means. A further method of justifying certain actions near the end of life is the doctrine of double effect. These paired concepts and the doctrine of double effect are analysed with special reference to their consequences. The application of the doctrine of double effect and the three distinctions relies on consideration of their consequences, allowing in practice what in theory is denied. This is important because it weakens the absolute case against euthanasia, which disallows any direct consequentialist appeal. If consequences count in the application of the doctrine and the distinctions, then they should also count directly prior to their application. This strengthens the argument for active euthanasia in certain cases.

Structural Characterization and Absolute Luminescence Efficiency Evaluation of Gd2O2S High Packing Density Ceramic Screens Doped with Tb3+ and Eu3+ for further Applications in Radiology

NASA Astrophysics Data System (ADS)

Dezi, Anna; Monachesi, Elenasophie; D'Ignazio, Michela; Scalise, Lorenzo; Montalto, Luigi; Paone, Nicola; Rinaldi, Daniele; Mengucci, Paolo; Loudos, George; Bakas, Athanasios; Michail, Christos; Valais, Ioannis; Fountzoula, Christine; Fountos, George; David, Stratos

2017-11-01

Rare earth activators are impurities added in the phosphor material to enhance probability of visible photon emission during the luminescence process. The main activators employed are rare earth trivalent ions such as Ce+3, Tb+3, Pr3+ and Eu+3. In this work, four terbium-activated Gd2O2S (GOS) powder screens with different thicknesses (1049 mg/cm2, 425.41 mg/cm2, 313 mg/cm2 and 187.36 mg/cm2) and one europium-activated GOS powder screen (232.18 mg/cm2) were studied to investigate possible applications for general radiology detectors. Results presented relevant differences in crystallinity between the GOS:Tb doped screens and GOS:Eu screens in respect to the dopant agent present. The AE (Absolute efficiency) was found to rise (i) with the increase of the X-ray tube voltage with the highest peaking at 110kVp and (ii) with the decrease of the thickness among the four GOS:Tb. Comparing similar thickness values, the europium-activated powder screen showed lower AE than the corresponding terbium-activated.

Numerical study of plasma generation process and internal antenna heat loadings in J-PARC RF negative ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shibata, T., E-mail: shibat@post.j-parc.jp; Ueno, A.; Oguri, H.

A numerical model of plasma transport and electromagnetic field in the J-PARC (Japan Proton Accelerator Research Complex) radio frequency ion source has been developed to understand the relation between antenna coil heat loadings and plasma production/transport processes. From the calculation, the local plasma density increase is observed in the region close to the antenna coil. Electrons are magnetized by the magnetic field line with absolute magnetic flux density 30–120 Gauss which leads to high local ionization rate. The results suggest that modification of magnetic configuration can be made to reduce plasma heat flux onto the antenna.

Power Balance and Impurity Studies in TCS

NASA Astrophysics Data System (ADS)

Grossnickle, J. A.; Pietrzyk, Z. A.; Vlases, G. C.

2003-10-01

A "zero-dimension" power balance model was developed based on measurements of absorbed power, radiated power, absolute D_α, temperature, and density for the TCS device. Radiation was determined to be the dominant source of power loss for medium to high density plasmas. The total radiated power was strongly correlated with the Oxygen line radiation. This suggests Oxygen is the dominant radiating species, which was confirmed by doping studies. These also extrapolate to a Carbon content below 1.5%. Determining the source of the impurities is an important question that must be answered for the TCS upgrade. Preliminary indications are that the primary sources of Oxygen are the stainless steel end cones. A Ti gettering system is being installed to reduce this Oxygen source. A field line code has been developed for use in tracking where open field lines terminate on the walls. Output from this code is also used to generate grids for an impurity tracking code.

Parametric scaling of neutral and ion excited state densities in an argon helicon source

NASA Astrophysics Data System (ADS)

McCarren, D.; Scime, E.

2016-04-01

We report measurements of the absolute density and temperature of ion and neutral excited states in an argon helicon source. The excited ion state density, which depends on ion density, electron density, and electron temperature, increases sharply with increasing magnetic field in the source. The neutral argon metastable density measurements are consistent with an increasing ionization fraction with increasing magnetic field strength. The ion temperature shows no evidence of increased heating with increasing magnetic field strength (which has only been observed in helicon sources operating at driving frequencies close to the lower hybrid frequency). The measurements were obtained through cavity ring down spectroscopy, a measurement technique that does not require the target excited state to be metastable or part of a fluorescence scheme; and is therefore applicable to any laser accessible atomic or ionic transition in a plasma.

A method for the microlensed flux variance of QSOs

NASA Astrophysics Data System (ADS)

Goodman, Jeremy; Sun, Ai-Lei

2014-06-01

A fast and practical method is described for calculating the microlensed flux variance of an arbitrary source by uncorrelated stars. The required inputs are the mean convergence and shear due to the smoothed potential of the lensing galaxy, the stellar mass function, and the absolute square of the Fourier transform of the surface brightness in the source plane. The mathematical approach follows previous authors but has been generalized, streamlined, and implemented in publicly available code. Examples of its application are given for Dexter and Agol's inhomogeneous-disc models as well as the usual Gaussian sources. Since the quantity calculated is a second moment of the magnification, it is only logarithmically sensitive to the sizes of very compact sources. However, for the inferred sizes of actual quasi-stellar objects (QSOs), it has some discriminatory power and may lend itself to simple statistical tests. At the very least, it should be useful for testing the convergence of microlensing simulations.

The three-dimensional steady radial expansion of a viscous gas from a sonic source into a vacuum.

NASA Technical Reports Server (NTRS)

Bush, W. B.; Rosen, R.

1971-01-01

The three-dimensional steady radial expansion of a viscous, heat-conducting, compressible fluid from a spherical sonic source into a vacuum is analyzed using the Navier-Stokes equations as a basis. It is assumed that the model fluid is a perfect gas having constant specific heats, a constant Prandtl number of order unity, and viscosity coefficients varying as a power of the absolute temperature. Limiting forms for the flow variable solutions are studied for the Reynolds number based on the sonic source conditions, going to infinity and the Newtonian parameter both fixed and going to zero. For the case of the viscosity-temperature exponent between .5 and 1, it is shown that the velocity as well as the pressure approach zero as the radial distance goes to infinity. The formulations of the distinct regions that span the domain extending from the sonic source to the vacuum are presented.

Increased Bone Marrow (BM) Plasma Level of Soluble CD30 and Correlations with BM Plasma Level of Interferon (IFN)-γ, CD4/CD8 T-Cell Ratio and Disease Severity in Aplastic Anemia

PubMed Central

Shi, Jun; Ge, Meili; Li, Xingxin; Shao, Yingqi; Yao, Jianfeng; Zheng, Yizhou

2014-01-01

Idiopathic aplastic anemia (AA) is an immune-mediated bone marrow failure syndrome. Immune abnormalities such as decreased lymphocyte counts, inverted CD4/CD8 T-cell ratio and increased IFN-γ-producing T cells have been found in AA. CD30, a surface protein belonging to the tumor necrosis factor receptor family and releasing from cell surface as a soluble form (sCD30) after activation, marks a subset of activated T cells secreting IFN-γ when exposed to allogeneic antigens. Our study found elevated BM plasma levels of sCD30 in patients with SAA, which were closely correlated with disease severity, including absolute lymphocyte count (ALC) and absolute netrophil count (ANC). We also noted that sCD30 levels were positively correlated with plasma IFN-γ levels and CD4/CD8 T-cell ratio in patients with SAA. In order to explain these phenomena, we stimulated T cells with alloantigen in vitro and found that CD30+ T cells were the major source of IFN-γ, and induced CD30+ T cells from patients with SAA produced significantly more IFN-γ than that from healthy individuals. In addition, increased proportion of CD8+ T cells in AA showed enhanced allogeneic response by the fact that they expressed more CD30 during allogeneic stimulation. sCD30 levels decreased in patients responded to immunosuppressive therapy. In conclusion, elevated BM plasma levels of sCD30 reflected the enhanced CD30+ T cell-mediated immune response in SAA. CD30 as a molecular marker that transiently expresses on IFN-γ-producing T cells, may participate in mediating bone marrow failure in AA, which also can facilitate our understanding of AA pathogenesis to identify new therapeutic targets. PMID:25383872

Detecting free-living steps and walking bouts: validating an algorithm for macro gait analysis.

PubMed

Hickey, Aodhán; Del Din, Silvia; Rochester, Lynn; Godfrey, Alan

2017-01-01

Research suggests wearables and not instrumented walkways are better suited to quantify gait outcomes in clinic and free-living environments, providing a more comprehensive overview of walking due to continuous monitoring. Numerous validation studies in controlled settings exist, but few have examined the validity of wearables and associated algorithms for identifying and quantifying step counts and walking bouts in uncontrolled (free-living) environments. Studies which have examined free-living step and bout count validity found limited agreement due to variations in walking speed, changing terrain or task. Here we present a gait segmentation algorithm to define free-living step count and walking bouts from an open-source, high-resolution, accelerometer-based wearable (AX3, Axivity). Ten healthy participants (20-33 years) wore two portable gait measurement systems; a wearable accelerometer on the lower-back and a wearable body-mounted camera (GoPro HERO) on the chest, for 1 h on two separate occasions (24 h apart) during free-living activities. Step count and walking bouts were derived for both measurement systems and compared. For all participants during a total of almost 20 h of uncontrolled and unscripted free-living activity data, excellent relative (rho  ⩾  0.941) and absolute (ICC (2,1)   ⩾  0.975) agreement with no presence of bias were identified for step count compared to the camera (gold standard reference). Walking bout identification showed excellent relative (rho  ⩾  0.909) and absolute agreement (ICC (2,1)   ⩾  0.941) but demonstrated significant bias. The algorithm employed for identifying and quantifying steps and bouts from a single wearable accelerometer worn on the lower-back has been demonstrated to be valid and could be used for pragmatic gait analysis in prolonged uncontrolled free-living environments.

Microgravity vibration isolation: An optimal control law for the one-dimensional case

NASA Technical Reports Server (NTRS)

Hampton, Richard D.; Grodsinsky, Carlos M.; Allaire, Paul E.; Lewis, David W.; Knospe, Carl R.

1991-01-01

Certain experiments contemplated for space platforms must be isolated from the accelerations of the platform. An optimal active control is developed for microgravity vibration isolation, using constant state feedback gains (identical to those obtained from the Linear Quadratic Regulator (LQR) approach) along with constant feedforward gains. The quadratic cost function for this control algorithm effectively weights external accelerations of the platform disturbances by a factor proportional to (1/omega) exp 4. Low frequency accelerations are attenuated by greater than two orders of magnitude. The control relies on the absolute position and velocity feedback of the experiment and the absolute position and velocity feedforward of the platform, and generally derives the stability robustness characteristics guaranteed by the LQR approach to optimality. The method as derived is extendable to the case in which only the relative positions and velocities and the absolute accelerations of the experiment and space platform are available.

Microgravity vibration isolation: An optimal control law for the one-dimensional case

NASA Technical Reports Server (NTRS)

Hampton, R. D.; Grodsinsky, C. M.; Allaire, P. E.; Lewis, D. W.; Knospe, C. R.

1991-01-01

Certain experiments contemplated for space platforms must be isolated from the accelerations of the platforms. An optimal active control is developed for microgravity vibration isolation, using constant state feedback gains (identical to those obtained from the Linear Quadratic Regulator (LQR) approach) along with constant feedforward (preview) gains. The quadratic cost function for this control algorithm effectively weights external accelerations of the platform disturbances by a factor proportional to (1/omega)(exp 4). Low frequency accelerations (less than 50 Hz) are attenuated by greater than two orders of magnitude. The control relies on the absolute position and velocity feedback of the experiment and the absolute position and velocity feedforward of the platform, and generally derives the stability robustness characteristics guaranteed by the LQR approach to optimality. The method as derived is extendable to the case in which only the relative positions and velocities and the absolute accelerations of the experiment and space platform are available.

Achieving Climate Change Absolute Accuracy in Orbit

NASA Technical Reports Server (NTRS)

Wielicki, Bruce A.; Young, D. F.; Mlynczak, M. G.; Thome, K. J; Leroy, S.; Corliss, J.; Anderson, J. G.; Ao, C. O.; Bantges, R.; Best, F.;

Numerical evaluation of magnetic absolute measurements with arbitrarily distributed DI-fluxgate theodolite orientations

NASA Astrophysics Data System (ADS)

Brunke, Heinz-Peter; Matzka, Jürgen

2018-01-01

At geomagnetic observatories the absolute measurements are needed to determine the calibration parameters of the continuously recording vector magnetometer (variometer). Absolute measurements are indispensable for determining the vector of the geomagnetic field over long periods of time. A standard DI (declination, inclination) measuring scheme for absolute measurements establishes routines in magnetic observatories. The traditional measuring schema uses a fixed number of eight orientations (Jankowski et al., 1996).

We present a numerical method, allowing for the evaluation of an arbitrary number (minimum of five as there are five independent parameters) of telescope orientations. Our method provides D, I and Z base values and calculated error bars of them.

A general approach has significant advantages. Additional measurements may be seamlessly incorporated for higher accuracy. Individual erroneous readings are identified and can be discarded without invalidating the entire data set. A priori information can be incorporated. We expect the general method to also ease requirements for automated DI-flux measurements. The method can reveal certain properties of the DI theodolite which are not captured by the conventional method.

Based on the alternative evaluation method, a new faster and less error-prone measuring schema is presented. It avoids needing to calculate the magnetic meridian prior to the inclination measurements.

Measurements in the vicinity of the magnetic equator are possible with theodolites and without a zenith ocular.

The implementation of the method in MATLAB is available as source code at the GFZ Data Center Brunke (2017).

Absolute optical extinction measurements of single nano-objects by spatial modulation spectroscopy using a white lamp

NASA Astrophysics Data System (ADS)

Billaud, Pierre; Marhaba, Salem; Grillet, Nadia; Cottancin, Emmanuel; Bonnet, Christophe; Lermé, Jean; Vialle, Jean-Louis; Broyer, Michel; Pellarin, Michel

2010-04-01

This article describes a high sensitivity spectrophotometer designed to detect the overall extinction of light by a single nanoparticle (NP) in the 10-4-10-5 relative range, using a transmission measurement configuration. We focus here on the simple and low cost scheme where a white lamp is used as a light source, permitting easy and broadband extinction measurements (300-900 nm). Using a microscope, in a confocal geometry, an increased sensitivity is reached thanks to a modulation of the NP position under the light spot combined with lock-in detection. Moreover, it is shown that this technique gives access to the absolute extinction cross-sections of the single NP provided that the incident electromagnetic field distribution experienced by the NP is accurately characterized. In this respect, an experimental procedure to characterize the light spot profile in the focal plane, using a reference NP as a probe, is also laid out. The validity of this approach is discussed and confirmed by comparing experimental intensity distributions to theoretical calculations taking into account the vector character of the tightly focused beam. The calibration procedure permitting to obtain the absolute extinction cross-section of the probed NP is then fully described. Finally, the force of the present technique is illustrated through selected examples concerning spherical and slightly elongated gold and silver NPs. Absolute extinction measurements are found to be in good consistency with the NP size and shape independently obtained from transmission electron microscopy, showing that spatial modulation spectroscopy is a powerful tool to get an optical fingerprint of the NP.

A model of the 8-25 micron point source infrared sky

NASA Technical Reports Server (NTRS)

Wainscoat, Richard J.; Cohen, Martin; Volk, Kevin; Walker, Helen J.; Schwartz, Deborah E.

1992-01-01

We present a detailed model for the IR point-source sky that comprises geometrically and physically realistic representations of the Galactic disk, bulge, stellar halo, spiral arms (including the 'local arm'), molecular ring, and the extragalactic sky. We represent each of the distinct Galactic components by up to 87 types of Galactic source, each fully characterized by scale heights, space densities, and absolute magnitudes at BVJHK, 12, and 25 microns. The model is guided by a parallel Monte Carlo simulation of the Galaxy at 12 microns. The content of our Galactic source table constitutes a good match to the 12 micron luminosity function in the simulation, as well as to the luminosity functions at V and K. We are able to produce differential and cumulative IR source counts for any bandpass lying fully within the IRAS Low-Resolution Spectrometer's range (7.7-22.7 microns as well as for the IRAS 12 and 25 micron bands. These source counts match the IRAS observations well. The model can be used to predict the character of the point source sky expected for observations from IR space experiments.

Measurement of absolute response functions and detection efficiencies of an NE213 scintillator up to 600 MeV

NASA Astrophysics Data System (ADS)

Kajimoto, Tsuyoshi; Shigyo, Nobuhiro; Sanami, Toshiya; Ishibashi, Kenji; Haight, Robert C.; Fotiades, Nikolaos

2011-02-01

Absolute neutron response functions and detection efficiencies of an NE213 liquid scintillator that was 12.7 cm in diameter and 12.7 cm in thickness were measured for neutron energies between 15 and 600 MeV at the Weapons Neutron Research facility of the Los Alamos Neutron Science Center. The experiment was performed with continuous-energy neutrons on a spallation neutron source by 800-MeV proton incidence. The incident neutron flux was measured using a 238U fission ionization chamber. Measured response functions and detection efficiencies were compared with corresponding calculations using the SCINFUL-QMD code. The calculated and experimental values were in good agreement for data below 70 MeV. However, there were discrepancies in the energy region between 70 and 150 MeV. Thus, the code was partly modified and the revised code provided better agreement with the experimental data.

Absolute wavelength calibration of a Doppler spectrometer with a custom Fabry-Perot optical system

NASA Astrophysics Data System (ADS)

Baltzer, M. M.; Craig, D.; Den Hartog, D. J.; Nishizawa, T.; Nornberg, M. D.

2016-11-01

An Ion Doppler Spectrometer (IDS) is used for fast measurements of C VI line emission (343.4 nm) in the Madison Symmetric Torus. Absolutely calibrated flow measurements are difficult because the IDS records data within 0.25 nm of the line. Commercial calibration lamps do not produce lines in this narrow range. A light source using an ultraviolet LED and etalon was designed to provide a fiducial marker 0.08 nm wide. The light is coupled into the IDS at f/4, and a holographic diffuser increases homogeneity of the final image. Random and systematic errors in data analysis were assessed. The calibration is accurate to 0.003 nm, allowing for flow measurements accurate to 3 km/s. This calibration is superior to the previous method which used a time-averaged measurement along a chord believed to have zero net Doppler shift.

Light curves of 213 Type Ia supernovae from the Essence survey

DOE PAGES

Narayan, G.; Rest, A.; Tucker, B. E.; ...

2016-05-06

The ESSENCE survey discovered 213 Type Ia supernovae at redshiftsmore » $$0.1\\lt z\\lt 0.81$$ between 2002 and 2008. We present their R- and I-band photometry, measured from images obtained using the MOSAIC II camera at the CTIO Blanco, along with rapid-response spectroscopy for each object. We use our spectroscopic follow-up observations to determine an accurate, quantitative classification, and precise redshift. Through an extensive calibration program we have improved the precision of the CTIO Blanco natural photometric system. We use several empirical metrics to measure our internal photometric consistency and our absolute calibration of the survey. Here, we assess the effect of various potential sources of systematic bias on our measured fluxes, and estimate the dominant term in the systematic error budget from the photometric calibration on our absolute fluxes is ~1%.« less

Method and apparatus for ultra-high-sensitivity, incremental and absolute optical encoding

NASA Technical Reports Server (NTRS)

Leviton, Douglas B. (Inventor)

1999-01-01

An absolute optical linear or rotary encoder which encodes the motion of an object (3) with increased resolution and encoding range and decreased sensitivity to damage to the scale includes a scale (5), which moves with the object and is illuminated by a light source (11). The scale carries a pattern (9) which is imaged by a microscope optical system (13) on a CCD array (17) in a camera head (15). The pattern includes both fiducial markings (31) which are identical for each period of the pattern and code areas (33) which include binary codings of numbers identifying the individual periods of the pattern. The image of the pattern formed on the CCD array is analyzed by an image processor (23) to locate the fiducial marking, decode the information encoded in the code area, and thereby determine the position of the object.

Light curves of 213 Type Ia supernovae from the Essence survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narayan, G.; Rest, A.; Tucker, B. E.

The ESSENCE survey discovered 213 Type Ia supernovae at redshiftsmore » $$0.1\\lt z\\lt 0.81$$ between 2002 and 2008. We present their R- and I-band photometry, measured from images obtained using the MOSAIC II camera at the CTIO Blanco, along with rapid-response spectroscopy for each object. We use our spectroscopic follow-up observations to determine an accurate, quantitative classification, and precise redshift. Through an extensive calibration program we have improved the precision of the CTIO Blanco natural photometric system. We use several empirical metrics to measure our internal photometric consistency and our absolute calibration of the survey. Here, we assess the effect of various potential sources of systematic bias on our measured fluxes, and estimate the dominant term in the systematic error budget from the photometric calibration on our absolute fluxes is ~1%.« less

Radio frequency cavity analysis, measurement, and calibration of absolute Dee voltage for K-500 superconducting cyclotron at VECC, Kolkata

DOE Office of Scientific and Technical Information (OSTI.GOV)

Som, Sumit; Seth, Sudeshna; Mandal, Aditya

2013-02-15

Variable Energy Cyclotron Centre has commissioned a K-500 superconducting cyclotron for various types of nuclear physics experiments. The 3-phase radio-frequency system of superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and {+-}0.2{sup 0}, respectively. The analysis of the RF cavity has been carried out using 3D Computer Simulation Technology (CST) Microwave Studio code and various RF parameters and accelerating voltages ('Dee' voltage) are calculated from simulation. During the RF system commissioning, measurement of different RF parameters has been done and absolute Dee voltage has been calibrated using a CdTemore » X-ray detector along with its accessories and known X-ray source. The present paper discusses about the measured data and the simulation result.« less

Self-mixing instrument for simultaneous distance and speed measurement

NASA Astrophysics Data System (ADS)

Norgia, Michele; Melchionni, Dario; Pesatori, Alessandro

2017-12-01

A novel instrument based on Self-mixing interferometry is proposed to simultaneously measure absolute distance and velocity. The measurement method is designed for working directly on each kind of surface, in industrial environment, overcoming also problems due to speckle pattern effect. The laser pump current is modulated at quite high frequency (40 kHz) and the estimation of the induced fringes frequency allows an almost instantaneous measurement (measurement time equal to 25 μs). A real time digital elaboration processes the measurement data and discards unreliable measurements. The simultaneous measurement reaches a relative standard deviation of about 4·10-4 in absolute distance, and 5·10-3 in velocity measurement. Three different laser sources are tested and compared. The instrument shows good performances also in harsh environment, for example measuring the movement of an opaque iron tube rotating under a running water flow.

The PMA Catalogue as a realization of the extragalactic reference system in optical and near infrared wavelengths

NASA Astrophysics Data System (ADS)

Akhmetov, Volodymyr S.; Fedorov, Peter N.; Velichko, Anna B.

2018-04-01

We combined the data from the Gaia DR1 and Two-Micron All Sky Survey (2MASS) catalogues in order to derive the absolute proper motions more than 420 million stars distributed all over the sky in the stellar magnitude range 8 mag < G < 21 mag (Gaia magnitude). To eliminate the systematic zonal errors in position of 2MASS catalogue objects, the 2-dimensional median filter was used. The PMA system of proper motion has been obtained by direct link to 1.6 millions extragalactic sources. The short analysis of the absolute proper motion of the PMA stars Catalogue is presented in this work. From a comparison of this data with same stars from the TGAS, UCAC4 and PPMXL catalogues, the equatorial components of the mutual rotation vector of these coordinate systems are determined.

Ensuring long-term stability of infrared camera absolute calibration.

PubMed

Kattnig, Alain; Thetas, Sophie; Primot, Jérôme

2015-07-13

Absolute calibration of cryogenic 3-5 µm and 8-10 µm infrared cameras is notoriously instable and thus has to be repeated before actual measurements. Moreover, the signal to noise ratio of the imagery is lowered, decreasing its quality. These performances degradations strongly lessen the suitability of Infrared Imaging. These defaults are often blamed on detectors reaching a different "response state" after each return to cryogenic conditions, while accounting for the detrimental effects of imperfect stray light management. We show here that detectors are not to be blamed and that the culprit can also dwell in proximity electronics. We identify an unexpected source of instability in the initial voltage of the integrating capacity of detectors. Then we show that this parameter can be easily measured and taken into account. This way we demonstrate that a one month old calibration of a 3-5 µm camera has retained its validity.

Investigation on the absolute and relative photoionization cross sections of 3 potential propargylic fuels.

PubMed

Winfough, Matthew; Meloni, Giovanni

2017-12-01

Absolute photoionization cross sections for 2 potential propargylic fuels (propargylamine and dipropargyl ether) along with the partial ionization cross sections for their dissociative fragments are measured and presented for the first time via synchrotron photoionization mass spectrometry. The experimental setup consists of a multiplexed orthogonal time-of-flight mass spectrometer and is located at the Advanced Light Source facility of the Lawrence Berkeley National Laboratory in Berkeley, California. Data for a third propargylic compound (propargyl alcohol) were taken; however, because of its low signal, due to its weakly bound cation, only the dissociative ionization fragment from the H-loss channel is observed and presented. Suggested pathways leading to formation of dissociative photoionization fragments along with CBS-QB3 calculated adiabatic ionization energies and appearance energies for the dissociative fragments are also presented. Copyright © 2017 John Wiley & Sons, Ltd.

Earth Radiation Budget Experiment scanner radiometric calibration results

NASA Technical Reports Server (NTRS)

Lee, Robert B., III; Gibson, M. A.; Thomas, Susan; Meekins, Jeffrey L.; Mahan, J. R.

1990-01-01

The Earth Radiation Budget Experiment (ERBE) scanning radiometers are producing measurements of the incoming solar, earth/atmosphere-reflected solar, and earth/atmosphere-emitted radiation fields with measurement precisions and absolute accuracies, approaching 1 percent. ERBE uses thermistor bolometers as the detection elements in the narrow-field-of-view scanning radiometers. The scanning radiometers can sense radiation in the shortwave, longwave, and total broadband spectral regions of 0.2 to 5.0, 5.0 to 50.0, and 0.2 to 50.0 micrometers, respectively. Detailed models of the radiometers' response functions were developed in order to design the most suitable calibration techniques. These models guided the design of in-flight calibration procedures as well as the development and characterization of a vacuum-calibration chamber and the blackbody source which provided the absolute basis upon which the total and longwave radiometers were characterized. The flight calibration instrumentation for the narror-field-of-view scanning radiometers is presented and evaluated.

Absolute calibration of neutron detectors on the C-2U advanced beam-driven FRC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magee, R. M., E-mail: rmagee@trialphaenergy.com; Clary, R.; Korepanov, S.

2016-11-15

In the C-2U fusion energy experiment, high power neutral beam injection creates a large fast ion population that sustains a field-reversed configuration (FRC) plasma. The diagnosis of the fast ion pressure in these high-performance plasmas is therefore critical, and the measurement of the flux of neutrons from the deuterium-deuterium (D-D) fusion reaction is well suited to the task. Here we describe the absolute, in situ calibration of scintillation neutron detectors via two independent methods: firing deuterium beams into a high density gas target and calibration with a 2 × 10{sup 7} n/s AmBe source. The practical issues of each methodmore » are discussed and the resulting calibration factors are shown to be in good agreement. Finally, the calibration factor is applied to C-2U experimental data where the measured neutron rate is found to exceed the classical expectation.« less

Absolute Density Calibration Cell for Laser Induced Fluorescence Erosion Rate Measurements

NASA Technical Reports Server (NTRS)

Domonkos, Matthew T.; Stevens, Richard E.

2001-01-01

Flight qualification of ion thrusters typically requires testing on the order of 10,000 hours. Extensive knowledge of wear mechanisms and rates is necessary to establish design confidence prior to long duration tests. Consequently, real-time erosion rate measurements offer the potential both to reduce development costs and to enhance knowledge of the dependency of component wear on operating conditions. Several previous studies have used laser-induced fluorescence (LIF) to measure real-time, in situ erosion rates of ion thruster accelerator grids. Those studies provided only relative measurements of the erosion rate. In the present investigation, a molybdenum tube was resistively heated such that the evaporation rate yielded densities within the tube on the order of those expected from accelerator grid erosion. This work examines the suitability of the density cell as an absolute calibration source for LIF measurements, and the intrinsic error was evaluated.

Cosmic chirality both true and false.

PubMed

Barron, Laurence D

2012-12-01

The discrete symmetries of parity P, time reversal T, and charge conjugation C may be used to characterize the properties of chiral systems. It is well known that parity violation infiltrates into ordinary matter via an interaction between the nucleons and electrons, mediated by the Z(0) particle, that lifts the degeneracy of the mirror-image enantiomers of a chiral molecule. Being odd under P but even under T, this P-violating interaction exhibits true chirality and so may induce absolute enantioselection under all circumstances. It has been suggested that CP violation may also infiltrate into ordinary matter via a P-odd, T-odd interaction mediated by the (as yet undetected) axion. This CP-violating interaction exhibits false chirality and so may induce absolute enantioselection in processes far from equilibrium. Both true and false cosmic chirality should be considered together as possible sources of homochirality in the molecules of life. Copyright © 2012 Wiley Periodicals, Inc.

Fast and accurate read-out of interferometric optical fiber sensors

NASA Astrophysics Data System (ADS)

Bartholsen, Ingebrigt; Hjelme, Dag R.

2016-03-01

We present results from an evaluation of phase and frequency estimation algorithms for read-out instrumentation of interferometric sensors. Tests on interrogating a micro Fabry-Perot sensor made of semi-spherical stimuli-responsive hydrogel immobilized on a single mode fiber end face, shows that an iterative quadrature demodulation technique (IQDT) implemented on a 32-bit microcontroller unit can achieve an absolute length accuracy of ±50 nm and length change accuracy of ±3 nm using an 80 nm SLED source and a grating spectrometer for interrogation. The mean absolute error for the frequency estimator is a factor 3 larger than the theoretical lower bound for a maximum likelihood estimator. The corresponding factor for the phase estimator is 1.3. The computation time for the IQDT algorithm is reduced by a factor 1000 compared to the full QDT for the same accuracy requirement.

Beyond Extreme Ultra Violet (BEUV) Radiation from Spherically symmetrical High-Z plasmas

NASA Astrophysics Data System (ADS)

Yoshida, Kensuke; Fujioka, Shinsuke; Higashiguchi, Takeshi; Ugomori, Teruyuki; Tanaka, Nozomi; Kawasaki, Masato; Suzuki, Yuhei; Suzuki, Chihiro; Tomita, Kentaro; Hirose, Ryouichi; Eshima, Takeo; Ohashi, Hayato; Nishikino, Masaharu; Scally, Enda; Nshimura, Hiroaki; Azechi, Hiroshi; O'Sullivan, Gerard

2016-03-01

Photo-lithography is a key technology for volume manufacture of high performance and compact semiconductor devices. Smaller and more complex structures can be fabricated by using shorter wavelength light in the photolithography. One of the most critical issues in development of the next generation photo-lithography is to increase energy conversion efficiency (CE) from laser to shorter wavelength light. Experimental database of beyond extreme ultraviolet (BEUV) radiation was obtained by using spherically symmetrical high-Z plasmas generated with spherically allocated laser beams. Absolute energy and spectra of BEUV light emitted from Tb, Gd, and Mo plasmas were measured with a absolutely calibrated BEUV calorimeter and a transmission grating spectrometer. 1.0 x 1012 W/cm2 is the optimal laser intensity to produced efficient BEUV light source plasmas with Tb and Gd targets. Maximum CE is achieved at 0.8% that is two times higher than the published CEs obtained with planar targets.

Absolute wavelength calibration of a Doppler spectrometer with a custom Fabry-Perot optical system.

PubMed

Baltzer, M M; Craig, D; Den Hartog, D J; Nishizawa, T; Nornberg, M D

2016-11-01

An Ion Doppler Spectrometer (IDS) is used for fast measurements of C VI line emission (343.4 nm) in the Madison Symmetric Torus. Absolutely calibrated flow measurements are difficult because the IDS records data within 0.25 nm of the line. Commercial calibration lamps do not produce lines in this narrow range. A light source using an ultraviolet LED and etalon was designed to provide a fiducial marker 0.08 nm wide. The light is coupled into the IDS at f/4, and a holographic diffuser increases homogeneity of the final image. Random and systematic errors in data analysis were assessed. The calibration is accurate to 0.003 nm, allowing for flow measurements accurate to 3 km/s. This calibration is superior to the previous method which used a time-averaged measurement along a chord believed to have zero net Doppler shift.

Absolute quantitation of intracellular metabolite concentrations by an isotope ratio-based approach

PubMed Central

Bennett, Bryson D; Yuan, Jie; Kimball, Elizabeth H; Rabinowitz, Joshua D

2009-01-01

This protocol provides a method for quantitating the intracellular concentrations of endogenous metabolites in cultured cells. The cells are grown in stable isotope-labeled media to near-complete isotopic enrichment and then extracted in organic solvent containing unlabeled internal standards in known concentrations. The ratio of endogenous metabolite to internal standard in the extract is determined using mass spectrometry (MS). The product of this ratio and the unlabeled standard amount equals the amount of endogenous metabolite present in the cells. The cellular concentration of the metabolite can then be calculated on the basis of intracellular volume of the extracted cells. The protocol is exemplified using Escherichia coli and primary human fibroblasts fed uniformly with 13C-labeled carbon sources, with detection of 13C-assimilation by liquid chromatography–tandem MS. It enables absolute quantitation of several dozen metabolites over ~1 week of work. PMID:18714298

Absolute calibration of neutron detectors on the C-2U advanced beam-driven FRC.

PubMed

Magee, R M; Clary, R; Korepanov, S; Jauregui, F; Allfrey, I; Garate, E; Valentine, T; Smirnov, A

2016-11-01

In the C-2U fusion energy experiment, high power neutral beam injection creates a large fast ion population that sustains a field-reversed configuration (FRC) plasma. The diagnosis of the fast ion pressure in these high-performance plasmas is therefore critical, and the measurement of the flux of neutrons from the deuterium-deuterium (D-D) fusion reaction is well suited to the task. Here we describe the absolute, in situ calibration of scintillation neutron detectors via two independent methods: firing deuterium beams into a high density gas target and calibration with a 2 × 10 7 n/s AmBe source. The practical issues of each method are discussed and the resulting calibration factors are shown to be in good agreement. Finally, the calibration factor is applied to C-2U experimental data where the measured neutron rate is found to exceed the classical expectation.

High tonnage forest biomass production systems from southern pine energy plantations

Treesearch

P. Jernigan; T. Gallagher; Dana Mitchell; L. Teeter

2011-01-01

The topic of declining fossil fuels and the absolute need for renewable energy sources is very evident in today’s society. The utilization of bio-fuels is necessary to meet goals set forth in the Energy Independence and Security Act of 2007. Included in the act are standards in which bio-fuels will play a major role in ensuring national energy security and the...

A new network of faint calibration stars from the near infrared spectrometer (NIRS) on the IRTS

NASA Technical Reports Server (NTRS)

Freund, Minoru M.; Matsuura, Mikako; Murakami, Hiroshi; Cohen, Martin; Noda, Manabu; Matsuura, Shuji; Matsumoto, Toshio

1997-01-01

The point source extraction and calibration of the near infrared spectrometer (NIRS) onboard the Infrared Telescope in Space (IRTS) is described. About 7 percent of the sky was observed during a one month mission in the range of 1.4 micrometers to 4 micrometers. The accuracy of the spectral shape and absolute values of calibration stars provided by the NIRS/IRTS were validated.

Water Quality for Hexachlorethane

DTIC Science & Technology

1988-03-01

50,000 to 100,000 bacterial cells/mL; therefore, the teat organisms wete provided with a food source during testing . Two replicates of five animals ...liver weight was significantly in- creased. Two animals died, one each during weeks 4 and 5. Dermal sensitization tests performed on guinea pigs...absolute body waights starting at week 4 in animals exposed to 260 ppm than in control rats, Relative liver, lung, kidney, and testes weights were increased

A Theory of Conditional Information with Applications.

DTIC Science & Technology

1994-03-01

reviewing inStru#66ns, searching dsting data sources, gathering and the collection of elformation. Send comments regarding On burden estimate or any other...residing at the nexus of so final analysis all information has a common context, many intellectual subtleties that have come into scientific namely the...a A b = 0). There is all too little expli- useful in managing data bases, combining data , cit distinction made between absolutely true statements

Debiased orbit and absolute-magnitude distributions for near-Earth objects

NASA Astrophysics Data System (ADS)

Granvik, Mikael; Morbidelli, Alessandro; Jedicke, Robert; Bolin, Bryce; Bottke, William F.; Beshore, Edward; Vokrouhlický, David; Nesvorný, David; Michel, Patrick

2018-09-01

The debiased absolute-magnitude and orbit distributions as well as source regions for near-Earth objects (NEOs) provide a fundamental frame of reference for studies of individual NEOs and more complex population-level questions. We present a new four-dimensional model of the NEO population that describes debiased steady-state distributions of semimajor axis, eccentricity, inclination, and absolute magnitude H in the range 17 < H < 25. The modeling approach improves upon the methodology originally developed by Bottke et al. (2000, Science 288, 2190-2194) in that it is, for example, based on more realistic orbit distributions and uses source-specific absolute-magnitude distributions that allow for a power-law slope that varies with H. We divide the main asteroid belt into six different entrance routes or regions (ER) to the NEO region: the ν6, 3:1J, 5:2J and 2:1J resonance complexes as well as Hungarias and Phocaeas. In addition we include the Jupiter-family comets as the primary cometary source of NEOs. We calibrate the model against NEO detections by Catalina Sky Surveys' stations 703 and G96 during 2005-2012, and utilize the complementary nature of these two systems to quantify the systematic uncertainties associated to the resulting model. We find that the (fitted) H distributions have significant differences, although most of them show a minimum power-law slope at H ∼ 20. As a consequence of the differences between the ER-specific H distributions we find significant variations in, for example, the NEO orbit distribution, average lifetime, and the relative contribution of different ERs as a function of H. The most important ERs are the ν6 and 3:1J resonance complexes with JFCs contributing a few percent of NEOs on average. A significant contribution from the Hungaria group leads to notable changes compared to the predictions by Bottke et al. in, for example, the orbit distribution and average lifetime of NEOs. We predict that there are 962-56+52 (802-42+48 ×103) NEOs with H < 17.75 (H < 25) and these numbers are in agreement with the most recent estimates found in the literature (the uncertainty estimates only account for the random component). Based on our model we find that relative shares between different NEO groups (Amor, Apollo, Aten, Atira, Vatira) are (39.4,54.4,3.5,1.2,0.3)%, respectively, for the considered H range and that these ratios have a negligible dependence on H. Finally, we find an agreement between our estimate for the rate of Earth impacts by NEOs and recent estimates in the literature, but there remains a potentially significant discrepancy in the frequency of Tunguska-sized and Chelyabinsk-sized impacts.

Chemistry of neutral species in the effluent of the micro atmospheric pressure plasma jet in water-helium admixture

NASA Astrophysics Data System (ADS)

Willems, Gert; Benedikt, Jan; von Keudell, Achim

2016-09-01

A thorough understanding and good control of produced neutral and charged species by cold atmospheric plasmas is essential for potential environmental and/or bio-medical applications. In this study we use the COST reference micro plasma jet (µ-APPJ), which is a radio-frequency capacitive coupled plasma source with 1 mm electrode distance, which has been operated in helium-water vapour mixture and has been studied as a potential source of hydroxyl radicals and hydrogen peroxide molecules. The water vapour concentration was up to 1.2%. Molecular Beam mass spectrometry is used as diagnostic tool. An absolute calibration of hydrogen peroxide was conducted using a double bubbler concept, because the ionization cross section for hydrogen peroxide is not available. Additionally the effluent chemistry was investigated by use of a 0D and 2D model. Absolute densities of hydrogen peroxide and hydroxyl radicals from atmospheric plasma will be presented. Their dependency on water vapour concentration in the carrier gas as well as distance to target have been investigated. The measured density is between 5E-13 cm-3 (2.4ppm) and 1.5E-14 cm-3 (7.2ppm) for both hydrogen peroxide molecules and hydroxyl radicals. The achieved results are in good agreement with other experiments.

Interpretation of the Arcade 2 Absolute Sky Brightness Measurement

NASA Technical Reports Server (NTRS)

Seiffert, M.; Fixsen, D. J.; Kogut, A.; Levin, S. M.; Limon, M.; Lubin, P. M.; Mirel, P.; Singal, J.; Villela, T.; Wollack, E.;

Arima model and exponential smoothing method: A comparison

NASA Astrophysics Data System (ADS)

Wan Ahmad, Wan Kamarul Ariffin; Ahmad, Sabri

2013-04-01

This study shows the comparison between Autoregressive Moving Average (ARIMA) model and Exponential Smoothing Method in making a prediction. The comparison is focused on the ability of both methods in making the forecasts with the different number of data sources and the different length of forecasting period. For this purpose, the data from The Price of Crude Palm Oil (RM/tonne), Exchange Rates of Ringgit Malaysia (RM) in comparison to Great Britain Pound (GBP) and also The Price of SMR 20 Rubber Type (cents/kg) with three different time series are used in the comparison process. Then, forecasting accuracy of each model is measured by examinethe prediction error that producedby using Mean Squared Error (MSE), Mean Absolute Percentage Error (MAPE), and Mean Absolute deviation (MAD). The study shows that the ARIMA model can produce a better prediction for the long-term forecasting with limited data sources, butcannot produce a better prediction for time series with a narrow range of one point to another as in the time series for Exchange Rates. On the contrary, Exponential Smoothing Method can produce a better forecasting for Exchange Rates that has a narrow range of one point to another for its time series, while itcannot produce a better prediction for a longer forecasting period.

Sagnac delay in the Kerr-dS spacetime: Implications for Mach's principle

NASA Astrophysics Data System (ADS)

Karimov, R. Kh.; Izmailov, R. N.; Garipova, G. M.; Nandi, K. K.

2018-02-01

Relativistic twin paradox can have important implications for Mach's principle. It has been recently argued that the behavior of the time asynchrony (different aging of twins) between two flying clocks along closed loops can be attributed to the existence of an absolute spacetime, which makes Mach's principle unfeasible. In this paper, we shall revisit, and support, this argument from a different viewpoint using the Sagnac delay. This is possible since the above time asynchrony is known to be exactly the same as the Sagnac delay between two circumnavigating light rays re-uniting at the orbiting source/receiver. We shall calculate the effect of mass M and cosmological constant Λ on the delay in the general case of Kerr-de Sitter spacetime. It follows that, in the independent limits M→ 0, spin a→ 0 and Λ → 0, while the Kerr-dS metric reduces to Minkowski metric, the clocks need not tick in consonance since there will still appear a non-zero observable Sagnac delay. While we do not measure spacetime itself, we do measure the Sagnac effect, which signifies an absolute substantive Minkowski spacetime instead of a void. We shall demonstrate a completely different limiting behavior of Sagnac delay, heretofore unknown, between the case of non-geodesic and geodesic source/observer motion.

Origin of the Louisville Ridge and its relationship to the Eltanin Fracture Zone System

NASA Astrophysics Data System (ADS)

Watts, A. B.; Weissel, J. K.; Duncan, R. A.; Larson, R. L.

1988-04-01

We have combined shipboard and Seasat altimeter derived data in an intergrated geological and geophysical study of the Louisville Ridge; a 3500-km-long seamount chain extending from the Tonga trench to the Eltanin Fracture Zone. A break in the smooth trend of the ridge at latitude 37.5°S has been recognized in both bathymetric and altimetric data. The 40Ar-39Ar dating of rocks dredged either side of the break suggest that it is analogous to the bend in the Hawaiian-Emperor seamount chain. Although the general trend of the ridge can be fit by small circles about Pacific absolute motion poles determined from other seamount chains, the new bathymetric and age data allow us to refine Pacific absolute motion poles. The continuity in smooth trend of the ridge and the Eltanin Fracture Zone suggests some relationship between them. However, a major offset developed on this transform between 60 and 80 Ma, prior to the oldest dated rocks from the ridge. Although magmatism was more or less continuous on the ridge during 28-60 Ma, it probably occurred on crust with little or no offset. Thus magmatism appears to have been little influenced by the developing fracture zone. By 28 Ma, the distance between the magmatic source and the fracture zone had decreased sufficiently for a portion of the ridge to have been emplaced on crust with an offset. After about 12 Ma, however, volcanic activity on the Louisville Ridge apparently waned, despite a possible influence on the magmatism of the fracture zone.

Application of PAH concentration profiles in lake sediments as indicators for smelting activity.

PubMed

Warner, Wiebke; Ruppert, Hans; Licha, Tobias

2016-09-01

The ability of lake sediment cores to store long-term anthropogenic pollution establishes them as natural archives. In this study, we focus on the influence of copper shale mining and smelting in the Mansfeld area of Germany, using the depth profiles of two sediment cores from Lake Süßer See. The sediment cores provide a detailed chronological deposition history of polycyclic aromatic hydrocarbons (PAHs) and heavy metals in the studied area. Theisen sludge, a fine-grained residue from copper shale smelting, reaches the lake via deflation by wind or through riverine input; it is assumed to be the main source of pollution. To achieve the comparability of absolute contaminant concentrations, we calculated the influx of contaminants based on the sedimentation rate. Compared to the natural background concentrations, PAHs are significantly more enriched than heavy metals. They are therefore more sensitive and selective for source apportionment. We suggest two diagnostic ratios of PAHs to distinguish between Theisen sludge and its leachate: the ratio fluoranthene to pyrene ~2 and the ratio of PAH with logKOW<5.7 to PAH with a logKOW>5.7 converging to an even lower value than 2.3 (the characteristic of Theisen sludge) to identify the particulate input in lake environments. Copyright © 2016 Elsevier B.V. All rights reserved.

The Sea Peoples, from Cuneiform Tablets to Carbon Dating

PubMed Central

Kaniewski, David; Van Campo, Elise; Van Lerberghe, Karel; Boiy, Tom; Vansteenhuyse, Klaas; Jans, Greta; Nys, Karin; Weiss, Harvey; Morhange, Christophe; Otto, Thierry; Bretschneider, Joachim

2011-01-01

The 13th century BC witnessed the zenith of the Aegean and Eastern Mediterranean civilizations which declined at the end of the Bronze Age, ∼3200 years ago. Weakening of this ancient flourishing Mediterranean world shifted the political and economic centres of gravity away from the Levant towards Classical Greece and Rome, and led, in the long term, to the emergence of the modern western civilizations. Textual evidence from cuneiform tablets and Egyptian reliefs from the New Kingdom relate that seafaring tribes, the Sea Peoples, were the final catalyst that put the fall of cities and states in motion. However, the lack of a stratified radiocarbon-based archaeology for the Sea People event has led to a floating historical chronology derived from a variety of sources spanning dispersed areas. Here, we report a stratified radiocarbon-based archaeology with anchor points in ancient epigraphic-literary sources, Hittite-Levantine-Egyptian kings and astronomical observations to precisely date the Sea People event. By confronting historical and science-based archaeology, we establish an absolute age range of 1192–1190 BC for terminal destructions and cultural collapse in the northern Levant. This radiocarbon-based archaeology has far-reaching implications for the wider Mediterranean, where an elaborate network of international relations and commercial activities are intertwined with the history of civilizations. PMID:21687714

Frequency and amplitude modulation of ultra-compact terahertz quantum cascade lasers using an integrated avalanche diode oscillator.

PubMed

Castellano, Fabrizio; Li, Lianhe; Linfield, Edmund H; Davies, A Giles; Vitiello, Miriam S

2016-03-15

Mode-locked comb sources operating at optical frequencies underpin applications ranging from spectroscopy and ultrafast physics, through to absolute frequency measurements and atomic clocks. Extending their operation into the terahertz frequency range would greatly benefit from the availability of compact semiconductor-based sources. However, the development of any compact mode-locked THz laser, which itself is inherently a frequency comb, has yet to be achieved without the use of an external stimulus. High-power, electrically pumped quantum cascade lasers (QCLs) have recently emerged as a promising solution, owing to their octave spanning bandwidths, the ability to achieve group-velocity dispersion compensation and the possibility of obtaining active mode-locking. Here, we propose an unprecedented compact architecture to induce both frequency and amplitude self-modulation in a THz QCL. By engineering a microwave avalanche oscillator into the laser cavity, which provides a 10 GHz self-modulation of the bias current and output power, we demonstrate multimode laser emission centered around 3 THz, with distinct multiple sidebands. The resulting microwave amplitude and frequency self-modulation of THz QCLs opens up intriguing perspectives, for engineering integrated self-mode-locked THz lasers, with impact in fields such as nano- and ultrafast photonics and optical metrology.

Frequency and amplitude modulation of ultra-compact terahertz quantum cascade lasers using an integrated avalanche diode oscillator

PubMed Central

Castellano, Fabrizio; Li, Lianhe; Linfield, Edmund H.; Davies, A. Giles; Vitiello, Miriam S.

2016-01-01

Mode-locked comb sources operating at optical frequencies underpin applications ranging from spectroscopy and ultrafast physics, through to absolute frequency measurements and atomic clocks. Extending their operation into the terahertz frequency range would greatly benefit from the availability of compact semiconductor-based sources. However, the development of any compact mode-locked THz laser, which itself is inherently a frequency comb, has yet to be achieved without the use of an external stimulus. High-power, electrically pumped quantum cascade lasers (QCLs) have recently emerged as a promising solution, owing to their octave spanning bandwidths, the ability to achieve group-velocity dispersion compensation and the possibility of obtaining active mode-locking. Here, we propose an unprecedented compact architecture to induce both frequency and amplitude self-modulation in a THz QCL. By engineering a microwave avalanche oscillator into the laser cavity, which provides a 10 GHz self-modulation of the bias current and output power, we demonstrate multimode laser emission centered around 3 THz, with distinct multiple sidebands. The resulting microwave amplitude and frequency self-modulation of THz QCLs opens up intriguing perspectives, for engineering integrated self-mode-locked THz lasers, with impact in fields such as nano- and ultrafast photonics and optical metrology. PMID:26976199

Fluorescence lifetime spectroscopy in multiple-scattering environments: an application to biotechnology

NASA Astrophysics Data System (ADS)

Cerussi, Albert E.; Gratton, Enrico; Fantini, Sergio

1999-07-01

Over the past few years, there has been significant research activity devoted to the application of fluorescence spectroscopy to strongly scattering media, where photons propagate diffusely. Much of this activity focused on fluorescence as a source of contrast enhancement in optical tomography. Our efforts have emphasized the quantitative recovery of fluorescence parameters for spectroscopy. Using a frequency-domain diffusion-based model, we have successfully recovered the lifetime, the absolute quantum yield, the fluorophore concentration, and the emission spectrum of the fluorophore, as well as the absorption and the reduced scattering coefficients at the emission wavelength of the medium in different measurements. In this contribution, we present a sensitive monitor of the binding between ethidium bromide and bovine cells in fresh milk. The spectroscopic contrast was the approximately tenfold increase in the ethidium bromide lifetime upon binding to DNA. The measurement clearly demonstrated that we could quantitatively measure the density of cells in the milk, which is an application vital to the tremendous economic burden of bovine subclinical mastitis detection. Furthermore, we may in principle use the spirit of this technique as a quantitative monitor of the binding of fluorescent drugs inside tissues. This is a first step towards lifetime spectroscopy in tissues.

Effect of solvents extraction on phytochemical components and biological activities of Tunisian date seeds (var. Korkobbi and Arechti).

PubMed

Thouri, Amira; Chahdoura, Hassiba; El Arem, Amira; Omri Hichri, Amel; Ben Hassin, Rihab; Achour, Lotfi

2017-05-04

The interest in natural antioxidants, especially polyphenols, is growing more and more thanks to their positive contribution to human health. Thus, the prevention from the harmful action of oxidative stress which has been involved in many diseases such as cancer, inflammation diabetes, and cardiovascular illness. Recent research proved the bioactive compounds richness of date seeds which could be a good biological matrix of natural antioxidants. Unfortunately, an important quantity of Tunisian dates seed is discarded yearly. In this study, different solvents extraction (water, methanol, absolute acetone and aqueous acetone 80%) were used and the evaluation of its effect on phytochemical level, in vitro antioxidant activities, in vitro hyperglycemia key enzymes inhibition and in vivo anti-inflammatory proprieties were established for Tunisian date seeds. The result revealed that the polar solvent exhibited the highest amount of bioactive compounds. The correlation between polyphenol compounds and the antioxidant potentiality explains the powerful effect of used polar solvents on inflammation, TBARS and hyperglycemia inhibition. Furthermore, it showed its higher capacity to scavenge radicals. Therefore, this big waste of Tunisian seeds could be used as cheap source of natural antioxidant compounds which are considered as a health challenge for the poor countries.

PHOTOMETRIC REDSHIFTS IN THE HAWAII-HUBBLE DEEP FIELD-NORTH (H-HDF-N)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, G.; Xue, Y. Q.; Kong, X.

2015-01-01

We derive photometric redshifts (z {sub phot}) for sources in the entire (∼0.4 deg{sup 2}) Hawaii-Hubble Deep Field-North (H-HDF-N) field with the EAzY code, based on point-spread-function-matched photometry of 15 broad bands from the ultraviolet (U band) to mid-infrared (IRAC 4.5 μm). Our catalog consists of a total of 131,678 sources. We evaluate the z {sub phot} quality by comparing z {sub phot} with spectroscopic redshifts (z {sub spec}) when available, and find a value of normalized median absolute deviation σ{sub NMAD} = 0.029 and an outlier fraction of 5.5% (outliers are defined as sources having |z{sub phot} – z{sub spec} |/(1more » + z{sub spec} ) > 0.15) for non-X-ray sources. More specifically, we obtain σ{sub NMAD} = 0.024 with 2.7% outliers for sources brighter than R = 23 mag, σ{sub NMAD} = 0.035 with 7.4% outliers for sources fainter than R = 23 mag, σ{sub NMAD} = 0.026 with 3.9% outliers for sources having z < 1, and σ{sub NMAD} = 0.034 with 9.0% outliers for sources having z > 1. Our z {sub phot} quality shows an overall improvement over an earlier z {sub phot} work that focused only on the central H-HDF-N area. We also classify each object as a star or galaxy through template spectral energy distribution fitting and complementary morphological parameterization, resulting in 4959 stars and 126,719 galaxies. Furthermore, we match our catalog with the 2 Ms Chandra Deep Field-North main X-ray catalog. For the 462 matched non-stellar X-ray sources (281 having z {sub spec}), we improve their z {sub phot} quality by adding three additional active galactic nucleus templates, achieving σ{sub NMAD} = 0.035 and an outlier fraction of 12.5%. We make our catalog publicly available presenting both photometry and z {sub phot}, and provide guidance on how to make use of our catalog.« less

Compound summer temperature and precipitation extremes over central Europe

NASA Astrophysics Data System (ADS)

Sedlmeier, Katrin; Feldmann, H.; Schädler, G.

2018-02-01

Reliable knowledge of the near-future climate change signal of extremes is important for adaptation and mitigation strategies. Especially compound extremes, like heat and drought occurring simultaneously, may have a greater impact on society than their univariate counterparts and have recently become an active field of study. In this paper, we use a 12-member ensemble of high-resolution (7 km) regional climate simulations with the regional climate model COSMO-CLM over central Europe to analyze the climate change signal and its uncertainty for compound heat and drought extremes in summer by two different measures: one describing absolute (i.e., number of exceedances of absolute thresholds like hot days), the other relative (i.e., number of exceedances of time series intrinsic thresholds) compound extreme events. Changes are assessed between a reference period (1971-2000) and a projection period (2021-2050). Our findings show an increase in the number of absolute compound events for the whole investigation area. The change signal of relative extremes is more region-dependent, but there is a strong signal change in the southern and eastern parts of Germany and the neighboring countries. Especially the Czech Republic shows strong change in absolute and relative extreme events.

Effects of ranitidine (antacid), food, and formulation on the pharmacokinetics of fostamatinib: results from five phase I clinical studies.

PubMed

Flanagan, Talia; Martin, Paul; Gillen, Michael; Mathews, David; Lisbon, Eleanor; Kruusmägi, Martin

2017-02-01

Fostamatinib is an orally dosed phosphate prodrug that is cleaved by intestinal alkaline phosphatase to the active metabolite R406. Clinical studies were performed to assess the effect of food and ranitidine on exposure, to support in vitro-in vivo relationships (IVIVR) understanding and formulation transitions and to investigate absolute oral bioavailability. A series of in vitro dissolution and clinical pharmacokinetic studies were performed to support the design and introduction of a new formulation, understand the impact of changes in in vitro dissolution on in vivo performance for two fostamatinib formulations, to characterize the effects of food and ranitidine on exposure, and determine the absolute oral bioavailability. The in vivo performance of fostamatinib was generally insensitive to changes in in vitro dissolution performance, although marked slowing of the dissolution rate did impact exposures. Food and ranitidine had minor effects on R406 exposure that were not considered clinically relevant. The absolute oral bioavailability of fostamatinib was 54.6 %. The absolute oral bioavailability of fostamatinib was ~55 %. Food and ranitidine had minor effects on R406 exposure. An in vitro dissolution versus clinical performance relationship was determined that supported formulation transitions.

Cold and intense OH radical beam sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ploenes, Ludger; Meerakker, Sebastiaan Y. T. van de; Haas, Dominik

2016-05-15

We present the design and performance of two supersonic radical beam sources: a conventional pinhole-discharge source and a dielectric barrier discharge (DBD) source, both based on the Nijmegen pulsed valve. Both designs have been characterized by discharging water molecules seeded in the rare gases Ar, Kr, or Xe. The resulting OH radicals have been detected by laser-induced fluorescence. The measured OH densities are (3.0 ± 0.6) × 10{sup 11} cm{sup -3} and (1.0 ± 0.5) × 10{sup 11} cm{sup -3} for the pinhole-discharge and DBD sources, respectively. The beam profiles for both radical sources show a relative longitudinal velocity spreadmore » of about 10%. The absolute rotational ground state population of the OH beam generated from the pinhole-discharge source has been determined to be more than 98%. The DBD source even produces a rotationally colder OH beam with a population of the ground state exceeding 99%. For the DBD source, addition of O{sub 2} molecules to the gas mixture increases the OH beam density by a factor of about 2.5, improves the DBD valve stability, and allows to tune the mean velocity of the radical beam.« less

Computation and visualization of the MacAdam limits for any lightness, hue angle, and light source

NASA Astrophysics Data System (ADS)

Martínez-Verdú, Francisco; Perales, Esther; Chorro, Elisabet; de Fez, Dolores; Viqueira, Valentín; Gilabert, Eduardo

2007-06-01

We present a systematic algorithm capable of searching for optimal colors for any lightness L* (between 0 and 100), any illuminant (D65, F2, F7, F11, etc.), and any light source reported by CIE. Color solids are graphed in some color spaces (CIELAB, SVF, DIN99d, and CIECAM02) by horizontal (constant lightness) and transversal (constant hue angle) sections. Color solids plotted in DIN99d and CIECAM02 color spaces look more spherical or homogeneous than the ones plotted in CIELAB and SVF color spaces. Depending on the spectrum of the light source or illuminant, the shape of its color solid and its content (variety of distinguishable colors, with or without color correspondence) change drastically, particularly with sources whose spectrum is discontinuous and/or very peaked, with correlated color temperature lower than 5500 K. This could be used to propose an absolute colorimetric quality index for light sources comparing the volumes of their gamuts, in a uniform color space.

Non-microbial sources of microbial volatile organic compounds.

PubMed

Choi, Hyunok; Schmidbauer, Norbert; Bornehag, Carl-Gustaf

2016-07-01

The question regarding the true sources of the purported microbial volatile organic compounds (MVOCs) remains unanswered. To identify microbial, as well as non-microbial sources of 28 compounds, which are commonly accepted as microbial VOCs (i.e. primary outcome of interest is Σ 28 VOCs). In a cross-sectional investigation of 390 homes, six building inspectors assessed water/mold damage, took air and dust samples, and measured environmental conditions (i.e., absolute humidity (AH, g/m(3)), temperature (°C), ventilation rate (ACH)). The air sample was analyzed for volatile organic compounds (μg/m(3)) and; dust samples were analyzed for total viable fungal concentration (CFU/g) and six phthalates (mg/g dust). Four benchmark variables of the underlying sources were defined as highest quartile categories of: 1) the total concentration of 17 propylene glycol and propylene glycol ethers (Σ17 PGEs) in the air sample; 2) 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (TMPD-MIB) in the air sample; 3) semi-quantitative mold index; and 4) total fungal load (CFU/g). Within severely damp homes, co-occurrence of the highest quartile concentration of either Σ17 PGEs or TMPD-MIB were respectively associated with a significantly higher median concentration of Σ 28 VOCs (8.05 and 13.38μg/m(3), respectively) compared to the reference homes (4.30 and 4.86μg/m(3), respectively, both Ps ≤0.002). Furthermore, the homes within the highest quartile range for Σ fungal load as well as AH were associated with a significantly increased median Σ 28 VOCs compared to the reference group (8.74 vs. 4.32μg/m(3), P=0.001). Within the final model of multiple indoor sources on Σ 28 VOCs, one natural log-unit increase in summed concentration of Σ17 PGEs, plus TMPD-MIB (Σ 17 PGEs + TMPD-MIB) was associated with 1.8-times (95% CI, 1.3-2.5), greater likelihood of having a highest quartile of Σ 28 VOCs, after adjusting for absolute humidity, history of repainting at least one room, ventilation rate, and mold index (P-value =0.001). Homes deemed severely mold damaged (i.e., mold index =1) were associated with 1.7-times (95% CI, 0.8-3.6), greater likelihood of having a highest quartile of Σ 28 VOCs, even though such likelihood was not significant (P-value =0.164). In addition, absolute humidity appeared to positively interact with mold index to significantly elevate the prevalence of the highest quartile category of Σ 28 VOCs. The indoor concentration of Σ 28 VOCs, which are widely accepted as MVOCs, are significantly associated with the markers of synthetic (i.e. Σ17 PGEs and TMPD-MIB), and to less extent, microbial (i.e., mold index) sources. Copyright © 2016 Elsevier Inc. All rights reserved.

Different responses of influenza epidemic to weather factors among Shanghai, Hong Kong, and British Columbia.

PubMed

Wang, Xi-Ling; Yang, Lin; He, Dai-Hai; Chiu, Alice Py; Chan, Kwok-Hung; Chan, King-Pan; Zhou, Maigeng; Wong, Chit-Ming; Guo, Qing; Hu, Wenbiao

2017-06-01

Weather factors have long been considered as key sources for regional heterogeneity of influenza seasonal patterns. As influenza peaks coincide with both high and low temperature in subtropical cities, weather factors may nonlinearly or interactively affect influenza activity. This study aims to assess the nonlinear and interactive effects of weather factors with influenza activity and compare the responses of influenza epidemic to weather factors in two subtropical regions of southern China (Shanghai and Hong Kong) and one temperate province of Canada (British Columbia). Weekly data on influenza activity and weather factors (i.e., mean temperature and relative humidity (RH)) were obtained from pertinent government departments for the three regions. Absolute humidity (AH) was measured by vapor pressure (VP), which could be converted from temperature and RH. Generalized additive models were used to assess the exposure-response relationship between weather factors and influenza virus activity. Interactions of weather factors were further assessed by bivariate response models and stratification analyses. The exposure-response curves of temperature and VP, but not RH, were consistent among three regions/cities. Bivariate response model revealed a significant interactive effect between temperature (or VP) and RH (P < 0.05). Influenza peaked at low temperature or high temperature with high RH. Temperature and VP are important weather factors in developing a universal model to explain seasonal outbreaks of influenza. However, further research is needed to assess the association between weather factors and influenza activity in a wider context of social and environmental conditions.

Synthesis of (R)- and (S)-10,16-dihydroxyhexadecanoic acid: cutin stereochemistry and fungal activation.

PubMed

Ahmed, Aqeel; Crawford, Terry; Gould, Stephanie; Ha, Y S; Hollrah, Monica; Noor-E-Ain, Farhana; Dickman, Martin B; Dussault, Patrick H

2003-05-01

The first asymmetric syntheses of the cutin monomers (R)- and (S)-10,16-dihydroxyhexadecanoic acid (10,16-DHPA) and confirmation of (S)(+)-absolute configuration for 10,16-DHPA derived from tomato are reported. The individual DHPA stereoisomers display differences in their ability to activate the fungal pathogen Colletotrichum trifolii.

20 CFR 665.330 - Are the NAFTA-TAA program requirements for rapid response also required activities?

Code of Federal Regulations, 2010 CFR

2010-04-01

... TRAINING ADMINISTRATION, DEPARTMENT OF LABOR STATEWIDE WORKFORCE INVESTMENT ACTIVITIES UNDER TITLE I OF THE... members of a group of workers (including those in any agricultural firm or subdivision of an agricultural... sales or production, or both, of such firm or subdivision have decreased absolutely; and (2) Imports...